CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of and claims the benefit of priority of Japanese Patent Applications Nos. 2008-222723, 2008-222728, and No. 2009-165984, filed on Aug. 29, 2008, Aug. 29, 2008, and Jul. 14, 2009, with the Japanese Patent Office, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a film deposition apparatus and a film deposition method for depositing a film on a substrate by carrying out cycles of supplying in turn at least two source gases to the substrate in order to form a layer of a reaction product, and a computer readable storage medium storing a computer program for causing the film deposition apparatus to carry out the film deposition method. 
     2. Description of the Related Art 
     As a film deposition technique in a semiconductor fabrication process, there is a technique in which a first reaction gas is adsorbed on a surface of a semiconductor wafer (referred to as a wafer hereinafter) under vacuum and then a second reaction gas is adsorbed on the surface of the wafer in order to form one or more atomic or molecular layers through reaction of the first and the second reaction gases on the surface of the wafer; and such an alternating adsorption of the gases is repeated plural times, thereby depositing a film on the wafer. This technique is referred to, for example, Atomic Layer Deposition (ALD) or Molecular Layer Deposition (MLD). This technique is advantageous in that the film thickness can be controlled at higher accuracy by the number of times alternately supplying the gases, and in that the deposited film can have excellent uniformity over the wafer. Therefore, this deposition method is thought to be promising as a film deposition technique that can address further miniaturization of semiconductor devices. 
     Such a film deposition method may be preferably used, for example, for depositing a dielectric material to be used as a gate insulator. When silicon dioxide (SiO 2 ) is deposited as the gate insulator, a bis(tertiary-butylamino) silane (BTBAS) gas or the like is used as a first reaction gas (source gas) and ozone gas or the like is used as a second gas (oxidation gas). 
     In order to carry out such a deposition method, use of a single-wafer deposition apparatus is being considered. The single-wafer deposition apparatus includes a vacuum chamber having a pedestal provided therein and a shower head placed at a top portion of the vacuum chamber facing the pedestal. With such a deposition method using the deposition apparatus, reaction gases are supplied from the shower head to a wafer placed on the pedestal, and unreacted gases and by-products are evacuated from a bottom portion of the chamber. In this case, when plural reaction gases are mixed inside the vacuum chamber, reaction products are generated. This results in the formation of particles. With this deposition apparatus, it is necessary to supply, for example, inert gas as purge gas to replace one reaction gas with another. Replacing of reaction gases takes a long time and the number of cycles may reach several hundred. This results in a problem of an extremely long process time. Therefore, a deposition method and apparatus that enable high throughput is desired. 
     Under these circumstances, use of an apparatus disclosed in Patent Documents 1-4 is being considered. In schematically describing this apparatus, the apparatus has a vacuum chamber including a pedestal for placing plural wafers arranged in a circumferential direction (rotation direction) and a gas supplying part being placed above the vacuum chamber facing the pedestal for supplying process gas to the wafers. The gas supplying part is arranged, for example, in plural areas in a circumferential direction so that they correspond to the arrangement of wafers on the pedestal. 
     In order to decompress the inside of the vacuum chamber having wafers placed on the pedestal at a predetermined process pressure, the pedestal and the plural gas supplying parts are relatively rotated around a vertical axis along with heating the wafers and supplying plural kinds of gases (the above-described first and second reaction gases) on the surface of the wafers from each of the gas supplying parts. Further, in order to prevent reaction gases from mixing inside the vacuum chamber, a process area formed by the first process gas and another process area formed by the second process gas are partitioned inside the vacuum chamber by providing physical partition walls between the gas supplying parts or forming a gas curtain with inert gas. 
     Accordingly, although plural kinds of gases are simultaneously supplied into the same vacuum chamber, because the process areas are partitioned for preventing reaction gases from mixing, the first and second reaction gases, from the standpoint of the rotating wafer, can be alternately supplied via the partition walls or the gas curtain. Therefore, a film deposition process is performed using the above-described method. Accordingly, benefits such as being able to perform film deposition in a short time owing to no need for gas replacement and being able to reduce the consumption amount of inert gas (e.g., purge gas) can be attained. 
     In introducing plural kinds of reaction gases into the same vacuum chamber, this apparatus not only needs to prevent the reaction gases from mixing with each other in the vacuum chamber but also needs to maintain a constant gas flow with respect to the wafers by strictly controlling the gas flow of the reaction gases in the vacuum chamber. In other words, because this apparatus has plural process areas formed in the vacuum chamber, turbulence of the gas flow to the wafers causes the size of the process areas, that is, the reaction time between the wafer and the reaction gases, to change. This may affect the quality of the thin film formed by the film deposition. 
     In a case where turbulence of gas flow of reaction gases inside the vacuum containers is caused in an in-plane part or a space between the surfaces of the wafers (e.g., a case where a necessary amount of reaction gas is not supplied to the wafers), there is a risk of the film thickness becoming reduced due to insufficient attraction of the reaction gases or degrading of film quality due to, for example, insufficient progress of an oxidation reaction. Further, in a case where reaction gases are mixed via the partition walls or the gas curtain due to turbulence of gas flow, reaction products are generated. The generation of the reaction products causes the formation of particles. Thus, although it is necessary to strictly control the gas flow of the reaction gases, the above-described partition walls or gas curtain is insufficient. Further, even in a case where there is a turbulence of gas flow during processing, such turbulence cannot be recognized. 
     Furthermore, because this apparatus processes the wafers while maintaining the inside of the vacuum chamber at a predetermined degree of vacuum (pressure), it is necessary to control both the degree of vacuum inside the vacuum chamber and the gas flow of the reaction gases in the vacuum chamber. Therefore, control of the gas flow is extremely difficult. Furthers because the degree of vacuum inside the vacuum chamber or the flow rate of the reaction gases changes according to the recipe of the process performed on the wafers, it is necessary to control the degree of vacuum or the gas flow of the reaction gases with respect to each recipe. This further makes the control difficult. Nevertheless, no consideration is made regarding the control of the gas flow in the above-described Patent Documents. 
     Patent Document 5 discloses a method of separating a vacuum chamber into a left-side area and a right-side area, forming a gas supply opening and an evacuation opening in each of the areas, supplying different gases in each of the areas, and evacuating gases from each of the areas. However, there is no mention regarding the gas flow inside the vacuum chamber, that is, regarding the flow rate of, for example, the gas evacuated from each evacuation opening. Therefore, even in a case where evacuation flow rate changes with time (e.g., due to accumulation of particles in the evacuation passage) and results in a loss of balance of the evacuation flow rate between the left and right areas (one side evacuation), such loss of balance cannot be recognized. Further, in a case where an evacuation pump is provided to each of plural evacuation channels, a difference of evacuation performance among the evacuation pumps may occur depending on the status of each evacuation pump. However, there is no mention in Patent Document 5 regarding such difference. 
     Furthermore, Patent Documents 6 through 8 disclose a film deposition apparatus preferably used for an Atomic Layer CVD method that causes plural gases to be alternately adsorbed on a target (a wafer). In this apparatus, a susceptor that holds the wafer is rotated, while source gases and purge gases are supplied to the susceptor from above. In this apparatus, a gas curtain is formed by inert gas, and the source gases and purge gases are separately evacuated from evacuation channels  30   a  and  30   b . However, as with the Patent Document 5, there is no mention regarding the flow rate of the gas evacuated from each of the evacuation channels  30   a ,  30   b.    
     Furthermore, there is known a method of providing an evacuation channel with a valve that can have its opening adjusted and estimating the flow rate of evacuation gas flowing in an evacuation channel from the opening of the valve. This method, however, does not measure the actual flow rate of evacuation gas. Therefore, the actual flow rate of evacuation cannot be recognized in a case where, for example, there is a change in the evacuation performance of the evacuation pump as described above. 
     Patent Document 1: U.S. Pat. No. 6,634,314 
     Patent Document 2: Japanese Patent Application Laid-Open Publication No. 2001-254181 (FIGS. 1, 2) 
     Patent Document 3: Japanese Patent Publication No. 3,144,664 (FIGS. 1, 2, claim 1) 
     Patent Document 4: Japanese Patent Application Laid-Open Publication No. H4-287912 
     Patent Document 5: U.S. Pat. No. 7,153,542 (FIGS. 6A, 6B) 
     Patent Document 6: Japanese Patent Application Laid-Open Publication No. 2007-247066 (paragraphs 0023 through 0025, 0058, FIGS. 12 and 18) 
     Patent Document 7: United States Patent Publication No. 2007-218701 
     Patent Document 8: United States Patent Publication No. 2007-218702 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the above circumstances, and is directed to a film deposition apparatus, a film deposition method, and a computer-readable storage medium storing a computer program that causes the film deposition apparatus to carry out the film deposition method, which enable film deposition by alternately supplying plural reaction gases to a substrate in a vacuum chamber to produce plural layers of the reaction products of the reaction gases on the substrate and reduce the amount of separation gas supplied to separation areas provided along a circumferential direction of a rotation table on which the substrate is placed to separate a first process area to which a first reaction gas is supplied and a second process area to which a second reaction gas is supplied. 
     In order to achieve the above objective, a first aspect of the present invention provides a film deposition apparatus for depositing a film on a substrate by carrying out a cycle of alternately supplying at least two kinds of reaction gases that react with each other to the substrate to produce a layer of a reaction product in a chamber, the film deposition apparatus including: a rotation table provided in the chamber, the rotation table having a substrate receiving area for mounting the substrate thereon; a first reaction gas supplying part configured to supply a first reaction gas to one surface of the rotation table on which the substrate receiving area is provided; a second reaction gas supplying part configured to supply a second reaction gas to the one surface, the second reaction gas supplying part being separated from the first reaction gas supplying part along a circumferential direction of the rotation table; a separation area located along the circumferential direction between a first process area to which the first reaction gas is supplied and a second process area to which the second reaction gas is supplied, the separation area including a separation gas supplying part from which a separation gas is supplied; a first evacuation channel having an evacuation port between the first process area and the separation area; a second evacuation channel having an evacuation port between the second process area and the separation area; a first evacuation part connected to the first evacuation channel via a first valve; a second evacuation part connected to the second evacuation channel via a second valve; a first pressure detecting part interposed between the first valve and the first evacuation part; a second pressure detecting part interposed between the second valve and the second evacuation part; a process pressure detecting part provided in at least one of the first and second valves; and a control part configured to output a control signal for controlling opening of the first and second valves based on a pressure detection value detected from each of the first and second pressure detecting parts so that each of the pressure inside the chamber and the flow ratio between the gases flowing in the first and second evacuation channels becomes a predetermined value, respectively. 
     A second aspect of the present invention provides a film deposition apparatus for depositing a film on a substrate by carrying out a cycle of alternately supplying at least two kinds of reaction gases that react with each other to the substrate to produce a layer of a reaction product in a chamber, the film deposition apparatus including: a rotation table provided in the chamber, the rotation table having a substrate receiving area for mounting the substrate thereon; a first reaction gas supplying part configured to supply a first reaction gas to one surface of the rotation table on which the substrate receiving area is provided; a second reaction gas supplying part configured to supply a second reaction gas to the one surfacer the second reaction gas supplying part being separated from the first reaction gas supplying part along a circumferential direction of the rotation table; a separation area located along the circumferential direction between a first process area to which the first reaction gas is supplied and a second process area to which the second reaction gas is supplied, the separation area including a separation gas supplying part from which a separation gas is supplied; a first evacuation channel having an evacuation port between the first process area and the separation area; a second evacuation channel having an evacuation port between the second process area and the separation area; a first evacuation part connected to the first evacuation channel via a first valve; a second evacuation part connected to the second evacuation channel via a second valve; a first process pressure detecting part interposed between the first valve and the first evacuation part; a second process pressure detecting part interposed between the second valve and the second evacuation part; and a control part configured to output a control signal for controlling opening of the first and second valves based on a pressure detection value detected from each of the first and second pressure detecting parts so that each of the pressure inside the chamber and the pressure difference between the first and second process areas becomes a predetermined value, respectively. 
     A third aspect of the present invention provides a film deposition method for depositing a film on a substrate by carrying out a cycle of alternately supplying at least two kinds of reaction gases that react with each other to the substrate to produce a layer of a reaction product in a chamber, the film deposition method including the steps of: mounting the substrate substantially horizontally onto a rotation table provided inside the chamber; rotating the rotation table; supplying a first reaction gas to one surface of the rotation table on which a substrate receiving area is provided, from a first reaction gas supplying part; supplying a second reaction gas to the one surface from a second reaction gas supplying part, the second reaction gas supplying part being separated from the first reaction gas supplying part along a circumferential direction of the rotation table; supplying a separation gas from a separation gas supplying part provided in a separation area located between the first reaction gas supplying part and the second reaction gas supplying part; evacuating the first reaction gas of the first process area from a first evacuation part via a first evacuation channel having an evacuation port between the first process area and the separation area; evacuating the second reaction gas of the second process area from a second evacuation part via a second evacuation channel having an evacuation port between the second process area and the separation area; detecting the pressure inside the chamber, a first pressure between a first valve of the first evacuation channel and the first evacuation part, and a second pressure between a second valve of the second evacuation channel and the second evacuation port; and adjusting opening of the first and second valves based on pressure detection values detected in the detecting step so that each of the pressure inside the chamber and the flow ratio between the gases flowing in the first and second evacuation channels becomes a predetermined value, respectively. 
     A fourth aspect of the present invention provides a film deposition method for depositing a film on a substrate by carrying out a cycle of alternately supplying at least two kinds of reaction gases that react with each other to the substrate to produce a layer of a reaction product in a chamber, the film deposition method including the steps of: mounting the substrate substantially horizontally onto a rotation table provided inside the chamber; rotating the rotation table; supplying a first reaction gas to one surface of the rotation table on which a substrate receiving area is provided, from a first reaction gas supplying part; supplying a second reaction gas to the one surface from a second reaction gas supplying part, the second reaction gas supplying part being separated from the first reaction gas supplying part along a circumferential direction of the rotation table; supplying a separation gas from a separation gas supplying part provided in a separation area located between the first reaction gas supplying part and the second reaction gas supplying part; evacuating the first process area from a first evacuation part via a first evacuation channel having an evacuation port between the first process area and the separation area; evacuating the second process area from a second evacuation part via a second evacuation channel having an evacuation port between the second process area and the separation area; detecting a first pressure between a first valve of the first evacuation channel and the first evacuation part and a second pressure between a second valve of the second evacuation channel and the second evacuation port; and adjusting opening of the first and second valves based on pressure detection values detected in the detecting step so that each of the pressure inside the chamber and the pressure difference between the first process area and the second process area becomes a predetermined value, respectively. 
     A fifth aspect of the present invention provides a film deposition apparatus for depositing a film on a substrate by carrying out a cycle of alternately supplying at least two kinds of reaction gases that react with each other to the substrate to produce a layer of a reaction product in a chamber, the film deposition apparatus including: a rotation table provided in the chamber, the rotation table having a substrate receiving area for mounting the substrate thereon; a first reaction gas supplying part configured to supply a first reaction gas to one surface of the rotation table on which the substrate receiving area is provided; a second reaction gas supplying part configured to supply a second reaction gas to the one surface, the second reaction gas supplying part being separated from the first reaction gas supplying part along a circumferential direction of the rotation table; a separation area located along the circumferential direction between a first process area to which the first reaction gas is supplied and a second process area to which the second reaction gas is supplied, the separation area including a separation gas supplying part from which a separation gas is supplied; a ceiling surface located on both sides of the separation gas supplying part relative to a rotation direction for forming a narrow space between the rotation table and the ceiling surface for allowing the separation gas to flow from the separation area to the first and second process areas; a center portion area located at a center part of the chamber, the center portion area having an ejecting port for ejecting the separation gas to the one surface of the rotation table; a first evacuation channel having an evacuation port between the first process area and the separation area; a second evacuation channel having an evacuation port between the second process area and the separation area; a first evacuation part connected to the first evacuation channel; and a second evacuation part connected to the second evacuation channel. 
     A sixth aspect of the present invention provides a film deposition method for depositing a film on a substrate by carrying out a cycle of alternately supplying at least two kinds of reaction gases that react with each other to the substrate to produce a layer of a reaction product in a chamber, the film deposition method including the steps of: mounting the substrate substantially horizontally onto a rotation table provided inside the chamber; rotating the rotation table; supplying a first reaction gas to one surface of the rotation table on which a substrate receiving area is provided, from a first reaction gas supplying part; supplying a second reaction gas to the one surface from a second reaction gas supplying part, the second reaction gas supplying part being separated from the first reaction gas supplying part along a circumferential direction of the rotation table; supplying a separation gas from a separation gas supplying part provided in a separation area located between the first reaction gas supplying part and the second reaction gas supplying part; diffusing the separation gas in a narrow space between the rotation table and a ceiling surface provided on both sides of the separation gas supplying part in a manner facing the rotation table by supplying the separation gas from the separation gas supplying part provided in the separation area between the first and second reaction gas supplying parts; ejecting the separation gas to the one surface of the rotation table from an ejection port formed in a center portion area located at a center part of the chamber; evacuating the separation gas and the first reaction gas from the first process area and evacuating the separation gas and the second reaction gas from the second process area by evacuating the separation gas and the first reaction gas via a first evacuation channel having an evacuation port between the first process area and the separation area and evacuating the separation gas and the second reaction gas via a second evacuation channel having an evacuation port between the second process area and the separation area; evacuating the separation gas and the first reaction gas from a first evacuation part connected to the first evacuation channel; and evacuating the separation gas and the second reaction gas from a second evacuation part connected to the second evacuation channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a vertical cross-sectional diagram of a film deposition apparatus according to a first embodiment of the present invention; 
         FIG. 2  is a perspective view illustrating a configuration of the inside of a film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 3  is a horizontal plan view of the film deposition apparatus according to the first embodiment of the present invention; 
         FIGS. 4A and 4B  are vertical cross-sectional diagrams illustrating process areas and a separation area of the film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 5  is a partial cross-sectional view of the film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 6  is a fragmentary perspective view of the film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 7  is a schematic diagram for describing the manner in which separation gas and purge gas flow in the film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 8  is a fragmentary perspective view of the film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 9  is a schematic diagram illustrating an example of a control part of the film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 10  is a flowchart illustrating an example of an overall operation performed by the film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 11  is a flowchart illustrating an example in a case of adjusting an evacuation flow rate with the film deposition apparatus according to the first embodiment of the present invention; 
         FIGS. 12A-12C  are schematic diagrams illustrating, for example, the flow rate of gas flowing in the evacuation channels of the film deposition apparatus according to the first embodiment of the present invention; 
         FIG. 13  is a schematic diagram illustrating a state of adjusting the flow rate of gas flowing in the evacuation channels of the film deposition apparatus according to the first embodiment of the present invention; 
         FIGS. 14A and 14B  is a schematic diagram illustrating, for example, the pressure in a chamber in a middle of an operation according to the first embodiment of the present invention; 
         FIG. 15  is a schematic diagram for describing a state where first and second reaction gases are separated by separation gases and evacuated according to the first embodiment of the present invention; 
         FIG. 16  is a schematic diagram illustrating an example of a film deposition apparatus according to a second embodiment of the present invention; 
         FIG. 17  is a flowchart illustrating an example in a case of adjusting an evacuation flow rate with the film deposition apparatus according to the second embodiment of the present invention; 
         FIG. 18  is a schematic diagram illustrating another example of the film deposition apparatus according to the second embodiment of the present invention; 
         FIGS. 19A and 19B  are schematic diagrams for describing measurements of a convex portion used as a separation area according to the second embodiment of the present invention; 
         FIG. 20  is a vertical cross-sectional view illustrating another example of a separation area according to the second embodiment of the present invention; 
         FIGS. 21A-21C  are vertical cross-sectional views illustrating another example of a convex portion used as a separation area according to the second embodiment of the present invention; 
         FIG. 22  is a horizontal cross-sectional view illustrating a film deposition apparatus according to an embodiment of the present invention; 
         FIG. 23  is a horizontal cross-sectional view illustrating a film deposition apparatus according to an embodiment of the present invention; 
         FIG. 24  is a perspective view illustrating a configuration of the inside of a film deposition apparatus according to an embodiment of the present invention; 
         FIG. 25  is a horizontal cross-sectional view illustrating a film deposition apparatus according to an embodiment of the present invention; 
         FIG. 26  is a vertical cross-sectional view illustrating a film deposition apparatus according to an embodiment of the present invention; 
         FIG. 27  is a plan view illustrating an example of a substrate processing system using a film deposition apparatus of the present invention; 
         FIG. 28  is a vertical cross-sectional view illustrating a film deposition apparatus according to another embodiment of the present invention; 
         FIG. 29  is a schematic diagram illustrating an example of a control part of the film deposition apparatus according to another embodiment of the present invention; 
         FIG. 30  is a flowchart illustrating an example of an overall operation performed on a substrate according to another embodiment of the present invention; 
         FIG. 31  is a flowchart illustrating an example of an overall operation performed on a substrate according to another embodiment of the present invention; 
         FIG. 32  is a vertical cross-sectional diagram taken along line I-I′ of  FIG. 34  illustrating a film deposition apparatus according to a third embodiment of the present invention; 
         FIG. 33  is a perspective view illustrating a configuration of the inside of the film deposition apparatus according to the third embodiment of the present invention; 
         FIG. 34  is a horizontal cross-sectional plan view of the film deposition apparatus according to the third embodiment of the present invention; 
         FIGS. 35A and 35B  are vertical cross-sectional views illustrating process areas and a separation area of the film deposition apparatus according to the third embodiment of the present invention; 
         FIG. 36  is a vertical cross-sectional view of a separation area of the film deposition apparatus according to the third embodiment of the present invention; 
         FIG. 37  is a perspective view of a reaction gas nozzle of the film deposition apparatus according to the third embodiment of the present invention; 
         FIG. 38  is a schematic diagram for describing a state where separation gas or purge gas flows in the film deposition apparatus according to the third embodiment of the present invention; 
         FIG. 39  is a fragmentary perspective view of the film deposition apparatus according to the third embodiment of the present invention; 
         FIG. 40  is a horizontal plan view illustrating a state where evacuation systems are provided to the film deposition apparatus according to the third embodiment of the present invention; 
         FIG. 41  is a schematic diagram for describing a state where first and second reaction gases are separated by separation gases and evacuated according to the third embodiment of the present invention; 
         FIG. 42  is a horizontal cross-sectional plan view illustrating a modified example of the film deposition apparatus according to the third embodiment of the present invention; 
         FIGS. 43A and 43B  are schematic diagrams for describing measurements of a convex portion used as a separation area according to the third embodiment of the present invention; 
         FIG. 44  is a horizontal schematic diagram illustrating a film deposition apparatus according to another embodiment of the present invention; 
         FIG. 45  is a horizontal cross-sectional plan view illustrating a film deposition apparatus according to another embodiment of the present invention; 
         FIG. 46  is a vertical cross-sectional view illustrating a film deposition apparatus according to another embodiment of the present invention; and 
         FIG. 47  is a schematic plan view illustrating another example of a substrate processing system using a film deposition apparatus of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Non-limiting, exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. In the drawings, the same or corresponding reference marks are given to the same or corresponding members or components. It is noted that the drawings are illustrative of the invention, and there is no intention to indicate scale or relative proportions among the members or components, alone or therebetween. Therefore, the specific thickness or size should be determined by a person having ordinary skill in the art in view of the following non-limiting embodiments. 
     According to the below-described embodiments of the present invention, process areas for processing plural reaction gases, which react with each other, are formed in the same vacuum chamber along a rotation direction of a rotation table. In performing thin film deposition by forming plural layers of a reaction product in the plural process areas by alternately passing a substrate through the plural process areas by using the rotation table, separation areas for supplying separation gas are provided between the process areas along with providing first and second evacuation channels with evacuation openings for separately evacuating the different reaction gases. Further, valves provided to each of the evacuation channels are adjusted so that the pressure in the vacuum chamber becomes a predetermined value, and the flow rate of the gas evacuated from each evacuation channel or the pressure difference between the process areas becomes a predetermined value. Accordingly, a suitable gas flow can be stably provided in both sides of the separation areas. Thus, because the gas flow of reaction gases on the surface of the substrate can be uniform, a thin film can be provided with a uniform film thickness and an even film quality with respect to an in-plane direction or in-between surfaces of the substrate. Further, bias of evacuation between the separation areas on both sides can be prevented. Therefore, the reaction gases can be prevented from passing through the separation areas and mixing with each other. Accordingly, reaction products can be prevented from being formed on areas other than the surface of the substrate. Thus, formation of particles can be prevented. 
     First Embodiment 
     Referring to  FIG. 1 , which is a cut-away diagram taken along I-I′ line in  FIG. 3 , a film deposition apparatus according to an embodiment of the present invention has a vacuum chamber  1  having a flattened cylinder shape, and a rotation table  2  that is located inside the chamber  1  and has a rotation center at a center of the vacuum chamber  1 . The vacuum chamber  1  is made so that a ceiling plate  11  can be separated from a chamber body  12 . The ceiling plate  11  is pressed onto the chamber body  12  via a ceiling member such as an O ring  13 , so that the vacuum chamber  1  is hermetically sealed. On the other hand, the ceiling plate  11  can be raised by a driving mechanism (not shown) when the ceiling plate  11  has to be removed from the chamber body  12 . 
     The rotation table  2  is fixed onto a cylindrically shaped core portion  21 . The core portion  21  is fixed on a top end of a rotational shaft  22  that extends in a vertical direction. The rotational shaft  22  penetrates a bottom portion  14  of the vacuum chamber  1  and is fixed at the lower end to a driving mechanism  23  that can rotate the rotational shaft  22  clockwise, in this embodiment. The rotation shaft  22  and the driving mechanism  23  are housed in a cylindrical case body  20  having an open upper surface. The case body  20  is hermetically fixed to a bottom surface of the bottom portion  14  via a flanged portion, which isolates an inner environment of the case body  20  from an outer environment. 
     As shown in  FIGS. 2 and 3 , plural (five in the illustrated example) circular concave portions  24 , each of which receives a semiconductor wafer (hereinafter referred to as “wafer”) W, are formed along a rotation direction (circumferential direction) in a top surface of the rotation table  2 , although only one wafer W is illustrated in  FIG. 3 .  FIGS. 4A and 4B  are expanded views of the rotation table  2  being cut across and horizontally expanded along its concentric circle. As shown in  FIG. 4A , the concave portion  24  has a diameter slightly larger, for example, by 4 mm than the diameter of the wafer W and a depth equal to a thickness of the wafer W. Therefore, when the wafer W is placed in the concave portion  24 , a surface of the wafer W is at the same elevation of a surface of the rotation table  2  (an area of the rotation table where the wafer W is not placed). If there is a relatively large difference in height between the surface of the wafer W and the surface of the rotation table  2 , a change of pressure occurs at the portion of the difference. Therefore, from the aspect of attaining uniformity of film thickness in the in-plane direction, it is preferable to match the elevation of the surface of the wafer W and the elevation of the surface of the rotation table  2 . While matching the elevation of the surface of the wafer W and the height of the surface of the rotation table  2  may signify that the height difference of the surfaces of the wafer W and the rotation table is less than or equal to approximately 5 mm, the difference has to be as close to zero as possible to the extent allowed by machining accuracy. In the bottom of the concave portion  24  there are formed three through holes (not shown) through which three corresponding elevation pins (see  FIG. 8 ) are raised/lowered. The elevation pins support a back surface of the wafer W and raises/lowers the wafer W. 
     The concave portions  24  are substrate receiving areas (wafer W receiving areas) provided to position the wafers W and prevent the wafers W from being thrown out by centrifugal force caused by rotation of the rotation table  2 . However, the wafer W receiving areas are not limited to the concave portions  24 , but may be performed by guide members that are provided along a circumferential direction on the surface of the rotation table  2  to hold the edges of the wafers W. In a case where the rotation table  2  is provided with a chuck mechanism (e.g., electrostatic chucks) for attracting the wafer W, the areas on which the wafers W are received by the attraction serve as the substrate receiving areas. 
     Referring again to  FIGS. 2 and 3 , the chamber  1  includes a first reaction gas nozzle  31 , a second reaction gas nozzle  32 , and separation gas nozzles  41 ,  42  above the rotation table  2 , all of which extend in radial directions and are arranged at predetermined angular intervals in a circumferential direction of the chamber  1 . With this configuration, the concave portions  24  can move through and below the nozzles  31 ,  32 ,  41 , and  42 . In the illustrated example, the second reaction gas nozzle  32 , the separation gas nozzle  41 , the first reaction gas nozzle  31 , and the separation gas nozzle  42  are arranged clockwise in this order. These gas nozzles  31 ,  32 ,  41 , and  42  penetrate the circumferential wall portion of the chamber body  12  and are supported by attaching their base ends, which are gas inlet ports  31   a ,  32   a ,  41   a ,  42   a , respectively, on the outer circumference of the wall portion. 
     Although the gas nozzles  31 ,  32 ,  41 ,  42  are introduced into the chamber  1  from the circumferential wall portion of the chamber  1  in the illustrated example, these nozzles  31 ,  32 ,  41 ,  42  may be introduced from a ring-shaped protrusion portion  5  (described later). In this case, an L-shaped conduit may be provided in order to be open on the outer circumferential surface of the protrusion portion  5  and on the outer top surface of the ceiling plate  11 . With such an L-shaped conduit, the nozzle  31  ( 32 ,  41 ,  42 ) can be connected to one opening of the L-shaped conduit inside the chamber  1  and the gas inlet port  31   a  ( 32   a ,  41   a ,  42   a ) can be connected to the other opening of the L-shaped conduit outside the chamber  1 . 
     As illustrated in  FIG. 3 , the reaction gas nozzle  31  is connected to a first gas supplying source  38   a  of bis(tertiary-butylamino) silane (BTBAS) (which is a first source gas) via a gas supply pipe  31   b  including a valve  36   a  and a flow rate adjusting part  37   a . The reaction gas nozzle  32  is connected to a second gas supplying source  38   b  of O3 (ozone) gas (which is a second source gas) via a gas supply pipe  31   b  including a valve  36   b  and a flow rate adjusting part  37   b . Further, the separation gas nozzle  41  is connected to a N2 gas supplying source  38   c  of N2 (nitrogen) (which is a separation gas as well as an inert gas) via a gas supply pipe  41   b  including a valve  36   c  and a flow rate adjusting part  37   c . The separation gas nozzle  42  is also connected to the N2 gas supplying source  38   c  via a gas supplying pipe  42   b  including a valve  36   d  and a flow rate adjusting part  37   d.    
     The gas supply pipe  31   b  provided between the reaction gas nozzle  31  and the valve  36   a  is connected to the N2 gas supplying source  38   c  via a valve  36   e  and a flow rate adjusting part  38   c . As described below, N2 gas is supplied into the chamber  1  from the reaction gas nozzle  31  in a case of adjusting the flow ratio of evacuation gas. Likewise, the gas supply pipe  32   b  provided between the reaction gas nozzle  32  and the valve  36   b  is connected to the N2 gas supplying source  38   c  via the valve  36   f  and the flow rate adjusting part  37   f . The valves  36   a - 36   f  and the flow rate adjusting parts  37   a - 37   f  constitute a gas supply system  39 . 
     The reaction gas nozzles  31 ,  32  have ejection holes  33  facing directly downward for ejecting reaction gases below. The ejection holes  33  are arranged at predetermined intervals (e.g., about 10 mm) in longitudinal directions of the reaction gas nozzles  31 ,  32 . The ejection holes  33  have an inner diameter of about 0.5 mm, for example. The reaction gas nozzles  31 ,  32  are a first reaction gas supplying portion and a second reaction gas supplying portion, respectively, in this embodiment. In addition, an area below the reaction gas nozzle  31  is a first process area  91  in which the BTBAS gas is adsorbed on the wafer W, and an area below the reaction gas nozzle  32  is a second process area  92  in which the O3 gas is adsorbed on the wafer W. 
     The separation gas nozzles  41 ,  42  are provided in separation areas D that are configured to separate the first process area  91  and the second process area  92 . As shown in  FIGS. 2 through 4 , in each of the separation areas D, a convex portion  4  is provided in a ceiling plate  11  of the chamber  1  in a manner protruding downwards. The convex portion has a top view shape of a sector. The convex portion  4  is formed by dividing a circle depicted along an inner circumferential wall of the chamber  1 . The circle has the rotation center of the rotation table  2  as its center. The convex portion  4  has a groove portion  43  provided at the circumferential center of the circle that extends in the radial direction of the circle. The separation gas nozzle  41  ( 42 ) is located in the groove portion  43 . The distance between the center axis of the separation gas nozzle  41  ( 42 ) and one side of the sector-shaped convex portion  4  (edge of the convex portion  4  towards an upstream side relative to relative to a rotation direction of the rotation table  2 ) is substantially equal to the distance between the center axis of the separation gas nozzle  41  ( 42 ) and the other side (edge of the convex portion  4  towards a downstream side relative to the rotation direction of the rotation table  2 ) of the sector-shaped convex portion  4 . 
     It is to be noted that, although the groove portion  43  is formed in a manner bisecting the convex portion  4  in this embodiment, the groove portion  42  may be formed so that an upstream side of the convex portion  4  relative to the rotation direction of the rotation table  2  is wider, in other embodiments. 
     Accordingly, in this embodiment, a flat low ceiling surface (first ceiling surface)  44  is provided as a lower surface of the convex portion  4  on both sides of the separation gas nozzle  41  ( 42 ) relative to the rotation direction of the rotation table  2 . Further, a high ceiling surface (second ceiling surface)  45 , which is positioned higher than the first ceiling surface  44 , is provided on both sides of the separation gas nozzle  41  ( 42 ) relative to the rotation direction of the rotation table  2 . The role of the convex portion  4  is to provide a separation space which is a narrow space between the convex portion  4  and the rotation table  2  for impeding the first and second reaction gases from entering the narrow space and preventing the first and second reaction gases from being mixed. 
     Taking the separation gas nozzle  41  as an example, the O3 gas from an upstream side of the rotation direction of the rotation table  2  is impeded from entering the space between the convex portion  4  and the rotation table  2 . Further, the BTBAS gas from a downstream side of the rotation direction of the rotation table  2  is impeded from entering the space between the convex portion  4  and the rotation table  2 . “Impeding the first and second reaction gases from entering” signifies that the N2 gas ejected as the separation gas from the separation gas nozzle  41  diffuses between the first ceiling surfaces  44  and the upper surfaces of the rotation table  2  and flows out to a space below the second ceiling surfaces  45 , which are adjacent to the corresponding first ceiling surfaces  44  in the illustrated example, so that the gases cannot enter the separation space from the space below the second ceiling surfaces  45 . “The gases cannot enter the separation space” not only signifies that the gases from the adjacent space below the second ceiling surfaces  45  are completely prevented from entering the space below the convex portion  4 , but that the gases from both sides cannot proceed farther toward the space below the convex portion  4  and thus be mixed with each other. Namely, as long as such effect can be attained, the separation area D can achieve the role of separating the first process area  91  and the second process area  92 . The narrowness of the narrow space is set so that the pressure difference between the narrow space (space below the convex portion  4 ) and the space adjacent to the narrow space (e.g., space below the second ceiling surface  45 ) is large enough to attain the effect of “the gases cannot enter the separation space”. The specific measurements of the narrow space differs depending on, for example, the area of the convex portion  4 . Further, the gases adsorbed on the wafer W can pass through below the convex portion  4 . Therefore, “impeding the first and second reaction gases from entering” signifies that the first and second reaction gases are in a gaseous phase. 
     In this embodiment, a wafer W having a diameter of about 300 mm is used as the target substrate. In this embodiment, at an area spaced about 140 mm from the rotation center of the rotation table  2  in the outer circumferential direction (border part between the convex portion  4  and the below-described convex portion  5 ), the convex portion  4  includes a part where the length is about 146 mm in the circumferential direction (length of arc concentric with the rotation table  2 ). Further, at an area corresponding to an outermost part of the wafer W receiving area (concave part  24 ), the convex portion includes a part where the length is about 502 mm in the circumferential direction. In the outermost part as illustrated in  FIG. 4A , the length L of convex portion  4  on each side of the separation nozzle  41  ( 42 ) with respect to the circumferential direction is about 246 mm. 
     As illustrated in  FIG. 4A , the height from a top surface of the rotation table  2  to the lower surface of the convex portion  4  (i.e. first ceiling surface  44 ) is indicated as “h”. The height h ranges from, for example, about 0.5 mm to 10 mm, and more preferably, about 4 mm. In this case, the number of rotations of the rotation table  2  is set to, for example, about 1 rpm-500 rpm. Accordingly, in order to attain a separating function at the separation area D, the size of the convex portion  4  and the height h from the surface of the rotation table  2  to the lower surface of the convex portion  4  (first ceiling surface  44 ) are to be set based on, for example, experimentation of the applicable range of the number of rotations of the rotation table  2 . 
     Not only nitrogen gas (N2) may be used as the separation gas but also inert gas such as argon (Ar) may be used. Further, other gases such as hydrogen (H 2 ) may be used. As long as the film deposition process is not affected, the kind of gas is not to be limited in particular. Further, not only inert gas such as the above-described N2 gas may be used as the gas for flow rate adjustment but also other gases may be used as long as the gas does not affect the film deposition process. In this embodiment, N2 gas is used as the separation gas as well as the inert gas; therefore, inert gas is not switched when initiating the film deposition process. Alternatively, different kinds of gases may be used for the separation gas and the inert gas. 
     A protrusion portion  5  is provided on a lower surface of the ceiling plate  11  so that the inner circumference of the protrusion portion  5  faces the outer circumference of the core portion  21 . The protrusion portion  5  opposes the rotation table  2  at an outer area of the core portion  21 . In addition, a lower surface of the protrusion portion  5  and a lower surface of the convex portion  4  form one plane surface. In other words, a height of the lower surface of the protrusion portion  5  from the rotation table  2  is the same as a height of the lower surface (ceiling surface  44 ) of the convex portion  4 .  FIGS. 4A and 4B  show the ceiling plate  11  being horizontally cut across an area including a portion substantially lower than the ceiling surface  45  but higher than the separation nozzles  41 ,  42 . The convex portion  4  may not only be formed integrally with the protrusion portion  5  but may also be formed separately from the protrusion portion  5 . 
     The configuration of the combination of the convex portion  4  and the separation nozzle  41  ( 42 ) is fabricated by forming the groove portion  43  in a sector-shaped plate to be the convex portion  4 , and locating the separation gas nozzle  41  ( 42 ) in the groove portion  43  in the above embodiment. However, two sector-shaped plates may be attached on the lower surface of the ceiling plate  11  by screws so that the two sector-shaped plates are located on both sides of the separation gas nozzle  41  ( 42 ). 
     As described above, the lower surface of the ceiling plate  11  of the chamber  1  (i.e. ceiling when viewed from the wafer receiving area (concave portion  24 ) of the rotation table  2  includes the first ceiling surface  44  and the second ceiling surface  45  provided in a circumferential direction in a manner where the second ceiling surface  45  is positioned higher than the first ceiling surface  45 .  FIG. 1  is a vertical cross-sectional view of an area having a high ceiling surface  45 .  FIG. 5  is a vertical cross-sectional view of an area having a low ceiling surface  44 . The convex portion  4  has a bent portion  46  that bends in an L-shape at the outer circumferential edge of the convex portion  4  (area at the outer rim of the chamber  1 ). The sector-shaped convex portion  4  is provided towards the ceiling plate  11  and is configured to be detachable from the chamber body  12 . Therefore, a slight gap(s) is provided between the outer peripheral surface of the bent portion and the chamber body  12 . The same as the convex portion  4 , the bent portion  46  is also provided for impeding reaction gases from entering and preventing the reaction gases from mixing. The gaps between the bent portion  46  and the rotation table  2  and between the bent portion  46  and the chamber body  12  are set to have substantially the same measurements as the height h of the ceiling surface  44  with respect to the surface of the rotation table  2 . In this embodiment, from the standpoint of the surface of the rotation table  2 , the inner surface of the bent portion  46  serves as an inner circumferential wall of the chamber  1 . 
     As illustrated in  FIG. 5 , the chamber body  12  has an inner circumferential wall formed as a vertical surface in the vicinity of the outer circumferential surface of the bent portion  46  in the separation area D. As illustrated in  FIG. 1 , in an area other than the separation area D, the chamber body  12  has a dented portion (dented towards the outer side) with a notch having a rectangular cross section. The dented portion faces, for example, an area extending from the outer circumferential surface of the rotation table  2  to a bottom surface part  14 . In the dented portion, the areas with pressure communication between the first and second process areas  91 ,  92  are referred to as first and second evacuation areas E 1  and E 2 , respectively. Accordingly, as illustrated in  FIGS. 1 and 3 , first and second evacuation ports  61  and  62  are formed at corresponding bottom parts of the first and second evacuation areas E 1  and E 2 . 
     As illustrated in  FIG. 1 , the first evacuation port  61  is connected to, for example, a vacuum pump (first evacuation part)  64   a  via a first evacuation channel  63   a . A first valve  65   a  is interposed between the first evacuation channel  63   a  and the vacuum pump  64   a . The first valve  65   a  includes, for example, an APC (Auto Pressure Controller) that can change the opening (degree in which the first valve  65   a  is opened). The flow rate of the gas flowing in the first evacuation channel  63   a  can be adjusted in correspondence with the opening of the first valve  65   a . A first process pressure detecting part  66   a  is connected to an upstream side of the first valve  65   a  (towards the chamber  1 ). A first pressure detecting part  67   a  is connected to a downstream side of the first valve  65   a  (towards the vacuum pump  64   a ). The first process pressure detecting part  66   a  and the first pressure detecting part  67   a  each includes a pressure gage. The first process pressure detecting part  66   a  is for measuring the pressure in the chamber  1  (upstream side of the first valve  65   a ). The first pressure detecting part  67   a  is for measuring the pressure between the first valve  65   a  and the vacuum pump  64   a . Based on the difference in the values detected by the first process pressure detecting part  66   a  and the first pressure detecting part  67   a , the below-described control part  80  calculates the flow rate of gas flowing inside the first evacuation channel  63   a  taking the pressure drop at the first evacuation channel  63   a  or the first valve  65   a  into consideration. The calculation may be performed using, for example, Bernoulli&#39;s law. 
     Likewise, the second evacuation port  62  is connected to, for example, a vacuum pump (first evacuation part)  64   b  via a second evacuation channel  63   b . A second valve  65   b  is interposed between the second evacuation channel  63   b  and the vacuum pump  64   b . The same as the first valve  65   a , the second valve  65   b  includes, for example, an APC (Auto Pressure Controller) that can change the opening (degree in which the second valve  65   b  is opened). The flow rate of the gas flowing in the second evacuation channel  63   b  can be adjusted in correspondence with the opening of the second valve  65   b . A second process pressure detecting part  66   b  is connected to an upstream side of the second valve  65   b  (towards the chamber  1 ). A second pressure detecting part  67   b  is connected to a downstream side of the second valve  65   b  (towards the vacuum pump  64   b ). The second process pressure detecting part  66   b  and the second pressure detecting part  67   b  each includes a pressure gage. The second process pressure detecting part  66   b  is for measuring the pressure in the chamber  1  (upstream side of the second valve  65   b ). The second pressure detecting part  67   b  is for measuring the pressure between the second valve  65   b  and the vacuum pump  64   b . Based on the difference in the values detected by the second process pressure detecting part  66   b  and the second pressure detecting part  67   b , the control part  80  calculates the flow rate of gas flowing inside the second evacuation channel  63   b  taking the pressure drop at the second evacuation channel  63   b  or the second valve  65   b  into consideration. Hereinafter, the first valve  65   a  may also be referred to as “valve M (Master)” and the second valve  65   b  may also be referred to as “valve S (Slave)”. 
     The first and second evacuation ports  61  and  62  are provided for ensuring a separating effect in the separation area D. When viewing the first and second evacuation ports  61 ,  62  from a plan position, the first and second evacuation ports  61 ,  62  are provided on both sides of the separation area D in the rotation direction. For example, when viewing the first evacuation port  61  from the rotation center of the rotation table  2 , the first evacuation port  61  is formed between the first process area  91  and the separation area D provided adjacent to the first process area  91  towards the downstream side of the first process area  91  with respect to the rotation direction. When viewing the second evacuation port  62  from the rotation center of the rotation table  2 , the second evacuation port  62  is formed between the second process area  92  and another separation area D provided adjacent to the second process area  92  towards the downstream side of the second process area  92 . Each of the evacuation ports  61 ,  62  is dedicated to evacuate a corresponding reaction gas (BTBAS gas and O3 gas). In this embodiment, the first evacuation port  61  is provided between the first reaction gas nozzle  31  and a line extending from an edge (edge towards the first reaction gas nozzle  31 ) of the separation area D provided towards the downstream side of the first process area  91  with respect to the rotation direction. The second evacuation port  62  is provided between the second reaction gas nozzle  32  and a line extending from an edge (edge towards the second reaction gas nozzle  31 ) of the separation area D provided towards the downstream side of the second process area  92  with respect to the rotation direction. In other words, as illustrated in  FIG. 3 , the first evacuation port  61  is provided between a straight line L 1  (passing through the center of the rotation table  2  and the first process area  91 ) and a straight line L 2  (passing through the center of the rotation table  2  and an upstream edge of the separation area D provided towards the downstream side of the first process area  91  with respect to the rotation direction). The second evacuation port  62  is provided between a straight line L 3  (dash-double-dot line passing through the center of the rotation table  2  and the second process area  92 ) and a straight line L 4  (dash-double-dot line passing through the center of the rotation table  2  and an upstream edge of the separation area D provided towards the downstream side of the second process area  92  with respect to the rotation direction). 
     Because the pressure detected from both the first process pressure detecting part  66   a  and the second process pressure detecting part  66   b  are substantially the same, a pressure value detected from either the first process pressure detecting part  66   a  or the second process pressure detecting part  66   b  can be used as the value of the pressure in the area upstream of the valves  65   a ,  65   b  for calculating the flow rate in each of the first and second evacuation channels  63   a ,  63   b . Because the pressure of the evacuation channels  63   a ,  63   b  located upstream of the valves  65   a ,  65   b  is substantially the same as the pressure inside the chamber  1 , a pressure value detected from another pressure detecting part provided in the chamber  1  may serve as the pressure value used to calculate the flow rate in each of the first and second evacuation channels  63   a ,  63   b  instead of using the pressure values detected by the process pressure detecting parts  66   a ,  66   b.    
     Although the two evacuation ports  61 ,  62  are made in the chamber body  12  in this embodiment, three evacuation ports may be provided in other embodiments. For example, an additional evacuation port may be made in an area between the second reaction gas nozzle  32  and the separation area D located upstream relative to the clockwise rotation of the rotation table  2  in relation to the second reaction gas nozzle  32 . In addition, a further additional evacuation port may be made somewhere in the chamber body  12 . While the evacuation ports  61 ,  62  are located below the rotation table  2  to evacuate the chamber  1  through an area between the inner circumferential wall of the chamber  1  and the outer circumferential surface of the rotation table  2  in the illustrated example, the evacuation ports may be located at a part other than the bottom portion  14  of the chamber  1 . For example, the evacuation ports may be located in the side wall of the chamber body  12 . In addition, when the evacuation ports  61 ,  62  are provided in the side wall of the chamber body  12 , the evacuation ports  61 ,  62  may be located higher than the rotation table  2 . In this case, the gases flow along the upper surface of the rotation table  2  into the evacuation ports  61 ,  62  located higher the rotation table  2 . Therefore, it is advantageous in that particles in the chamber  1  are not blown upward by the gases, compared to when the evacuation ports are provided, for example, in the ceiling plate  11 . 
     As shown in  FIGS. 1 and 6 , a heater unit (heating portion)  7  is provided in a space between the bottom portion  14  of the chamber  1  and the rotation table  2 , so that the wafers W placed on the rotation table  2  are heated through the rotation table  2  at a temperature determined by a process recipe. In addition, a cover member  71  is provided beneath the rotation table  2  and near the outer circumference of the rotation table  2  in order to surround the heater unit  7 , so that the space where the heater unit  7  is located is partitioned from the outside area of the cover member  71 . The cover member  71  has a flange portion  71   a  at the top. The flange portion  71   a  is arranged so that a slight gap is maintained between the back surface of the rotation table  2  and the flange portion in order to prevent gas from flowing inside the cover member  71 . 
     At an area located towards the bottom portion  14  and more towards the rotation center than the space where the heater unit  7  is provided, narrow spaces are provided in the vicinity of the center of the lower surface of the rotation table  2  and the core portion  21 . Further, slight gaps, which are provided at a penetration hole through which the rotation shaft  22  passes, are in communication with the inside of the case body  20 . A purge gas supplying pipe  72  is connected to the case body for supplying a purge gas such as N2 gas to the aforementioned narrow spaces. Purge gas supplying pipes  73  are connected to plural areas in the circumferential direction at the bottom portion of the chamber  1  for purging the space where the heater unit  7  is provided. 
     By providing the purge gas supplying pipes  72 ,  73 , N2 gas is purged into the space extending from the inside of the case body  20  to the area where the heater unit  7  is provided. The purge gas is evacuated from the gap between the rotation table  2  and the cover member  71  to the evacuation ports  61 ,  62  via an evacuation area E. Accordingly, because the BTBAS gas or O3 gas is prevented from circling around from one side of the first process area  91  and the second process area  92  to the other side of the first process area  91  and the second process area  92  via a lower part of the rotation table  2 , the purge gas plays the role of a separation gas. 
     A gas separation supplying pipe  51  is connected to the top center portion of the ceiling plate  11  of the chamber  1 , so that N2 gas is supplied as a separation gas to a space  52  between the ceiling plate  11  and the core portion  21 . The separation gas, which is supplied to the space  52 , is ejected towards the circumferential edges through the thin gap  50  between the protrusion portion  5  and the rotation table  2  and then along the wafer receiving area of the rotation table  2 . Because the separation gas fills the space surrounded by the protrusion portion  5 , reaction gases (BTBAS gas or O3 gas) can be prevented from mixing via the center portion of the rotation table  2  between the first process area  91  and the second process area  92 . That is, the film deposition apparatus according to this embodiment is divided into a rotation center portion of the rotation table  2  and the chamber  1  for separating the atmosphere between the first process area  91  and the second process area  92 . Further, the film deposition apparatus according to this embodiment is provided with a center area C having an ejection opening formed along a rotation direction at the center portion of the rotation table  2  for ejecting the separation gas on the surface of the rotation table  2 . The ejection opening corresponds to the narrow gap  50  between the protrusion portion  5  and the rotation table  2 . 
     As illustrated in  FIGS. 2, 3, and 3 , a transfer opening  15  is formed in a side wall of the chamber  1  for transferring a wafer W between an outside transfer arm  10  and the rotation table  2 . The transfer opening  15  is provided with a gate valve (not illustrated) by which the transfer opening  15  is opened or closed. When a concave portion (wafer receiving area)  24  of the rotation table  2  is in alignment with the transfer opening  15 , the wafer W is transferred into the chamber  1  and placed in the concave portion  24  as a wafer receiving portion of the rotation table  2  from the transfer arm  10 . In order to lower/raise the wafer W into/from the concave portion  24 , there are provided elevation pins  16  that are raised or lowered through corresponding through holes formed in the concave portion  24  of the rotation table  2  by an elevation mechanism (not illustrated). 
     As illustrated in  FIG. 9 , the film deposition apparatus according to an embodiment of the present invention includes a control part  80  including a computer for controlling overall operations of the film deposition apparatus. The control part  80  includes a CPU  81 , a memory  82 , a processing program  83 , a work memory  84 , and a timer  86 . In the memory  82 , processing conditions (e.g., flow rate Va of BTBAS gas supplied from the first reaction gas nozzle  31 , flow rate Vb of O3 gas supplied from the second reaction gas nozzle  32 , process pressure P, flow ratio F of gas evacuated from the first evacuation channel  63   a  and the second evacuation channel  63   b  (i.e. flow rate of gas flowing in the second evacuation channel/flow rate of gas flowing in the first evacuation channel) are recorded thereto with respect to each recipe. In a steady state, the flow ratio F of the gases is set so that the flow of gas supplied to the wafer W in the first and second process chambers  91 ,  92  is constant (stable) with respect to an in-plane direction or in-between surfaces of the wafers W. For example, process temperature or a process pressure is stabilized to a value of a corresponding recipe. Further, the values of the flow rate of gas evacuated from the first and second evacuation channels  63   a ,  63   b  are set to be a flow rate corresponding to the gas supplied from the first reaction gas nozzle  31  and the second reaction gas nozzle  32  (including N2 gas supplied as purge gas). 
     The processing program  83  has commands assembled thereto for processing the wafer W by loading a corresponding recipe recorded in the memory  82  to the work memory  84 , transmitting control signals to each part of the film deposition apparatus according to the recipe, and executing each of the below-described steps. The processing program  83  is for setting a value of a processing temperature read out from a recipe before the BTBAS gas or O3 gas is supplied (i.e. before a film deposition process). Further, N2 gas is supplied into the chamber  1  at a flow rate substantially the same as the total flow rate of gas supplied during processing. In this state, the opening of the first valve  65   a  and the opening of the second valve  65   b  are adjusted according to each pressure value detected by the first process pressure detecting part  66   a  ( 66   b ) and a pressure detecting part  67  so that the flow ratio F evacuated from the first and second evacuation channels  63   a  and  63   b  and the pressure P (degree of vacuum) inside the chamber  1  become predetermined values, to thereby stabilize the flow of gas supplied to the wafer W (steady state). After reaching the steady state, the processing program  83  commands a film deposition process to be executed in which BTBAS gas or O3 gas is supplied. In adjusting the flow ratio F of the evacuation gases and the pressure inside the chamber  1 , the adjustment is repeated for a predetermined time (number of times), for example, performing a first step of adjusting the pressure P inside the chamber  1  with the first valve  65   a , performing a second step of adjusting the flow ratio of the evacuation gases with the second valve  65   b , and then performing the first step again (described in detail below). Although the flow ratio F of the evacuation gases is different with respect to each recipe, the flow ratio F of the evacuation gases may be the same with respect to each recipe. 
     A timer  86  is for setting the time (number of times) for repeating the valve  65  adjustment by the processing program  83 . For example, the time for the repetition may be set to automatic or may be set by a user according to each recipe. 
     The processing program  83  may be installed to the control part  80  from a storage medium such as a hard disk, a compact disk, a magneto-optical magnetic disk, a memory card, or a flexible disk. 
     A film deposition operation according to an embodiment of the present invention is described with reference to  FIGS. 10-15 . First, a recipe is read out from the memory  82 . Then, agate valve (not illustrated) is opened, and a wafer W is transferred into the concave portion  24  of the rotation table  2  from outside via the transfer opening  15  by the transfer arm  10  (Step S 11 ). The transfer is performed by raising or lowering the elevation pins  16  from the bottom portion of the chamber  1  via the through holes formed at the bottom surface of the concave portion  24  as illustrated in  FIG. 8 . In this example, the transfer is performed by intermittently rotating the rotation table  2  and placing wafers W on five corresponding concave portions  24  of the rotation table  2 . Then, the rotation table  2  is rotated clockwise at the substantially the same number of rotations when performing film deposition (Step S 12 ). Then, the adjustment of the pressure P inside the chamber  1  and the adjustment of the flow ratio F of evacuation gases are performed in Step S 13  (described in detail in Steps S 21 -S 28 ). 
     First, the chamber  1  is evacuated by fully opening the first and second valves  65   a ,  65   b  together with heating the wafer W at a predetermined temperature (e.g., 300° C.) with the heater unit  7  (Step S 21 ). For example, the wafer W is heated to a predetermined temperature by heating the rotation table  2  beforehand to a temperature of 300° C. with the heater unit  7  and placing the wafer W on the rotation table  2 . Then, N2 gas is supplied into the chamber  1  in substantially the same flow rate as the total flow rate of gas supplied in the chamber  1  when performing the below-described film deposition process. In order to attain substantially the same flow rate as the flow rate of gas supplied from the nozzles  31 ,  32 ,  41 ,  42  during the film deposition process, each of the separation gas nozzles  41 ,  42  supplies N2 gas with a flow rate of 20000 sccm, the first reaction gas nozzle  31  supplies N2 gas with a flow rate of 100 sccm, and the second reaction gas nozzle  32  supplies N2 gas with a flow rate of 10000 sccm. Further, the separation gas supplying pipe  51  and the purge gas supplying pipe  72  also supply N2 gas with a predetermined flow rate to the center portion area C and the aforementioned narrow gaps. Further, in order to attain a predetermined value of a recipe, the pressure value P 1  is set to, for example, 1067 Pa (8 Torr), and the flow ratio F 1  is set to, for example, 1.5 (Step S 22 ). Then, the timer  86  is set for setting the time t 1  for repeating the below-described Steps S 24 -S 27  (Step S 23 ). 
     As illustrated in  FIG. 13 , in order for the pressure P in the chamber  1  to be a predetermined pressure value P 1  (e.g., 1067 Pa (8 Torr), the opening (A 1 ) of the first valve  65   a  is adjusted (Step S 24 ). For example, in order to reduce the flow rate of gas flowing in the first evacuation channel  63   a , the opening of the first valve  65   a  is reduced. The flow rate of each gas flowing in the evacuation channels  63   a ,  63   b  (Qa 1 , Qb 1 ) is calculated according to the pressure difference between the pressure of an upstream side (front) of the first valve  65   a  and the pressure of a downstream side (back) of the first valve  65   a  (ΔPa 1 ) and the pressure difference between the pressure of an upstream side (front) of the second valve  65   b  and the pressure of a downstream side (back) of the second valve  65   b  (ΔPb 1 ). Then, the gas flow ratio F (Qb 1 /Qa 1 ) is obtained based on the calculated flow rate, to thereby determine whether the flow ratio is a predetermined value F 1  (Step S 25 ). In a case where the flow ratio is equal to the predetermined value F 1 , the operation proceeds to the below-described film deposition process of Step S 14 . In a case where the flow ratio is greater than the predetermined value F 1 , the opening (B 1 ) of the second valve  65   b  is reduced so that the flow ratio equals to the predetermined value F 1  (Step S 26 ). 
     Then, it is determined whether the pressure P is deviated from a predetermine value P 1  (Step S 27 ). If the pressure P is not deviated from the predetermined value P 1 , the operation proceeds to the below-described film deposition process of Step S 14 . In a case where the pressure P is deviated from the predetermined value P 1 , it is determined whether the time used in performing the above-described steps S 24 -S 27  has reached a predetermined repetition time t 1  (Step S 28 ). The steps of S 24 -S 27  are repeated when i) the time used in performing the step S 24 -S 27  reaches the repetition time t 1 , ii) the flow ratio F equals to the predetermined value F 1  in Step S 25 , or iii) the pressure P equals to the predetermined value P 1 . For example, in a case where the pressure P is greater than P 1  by the adjustment of the opening of the valve  65   b  (Step S 26 ), the opening of the valve  65   a  is increased. In a case where the pressure P is less than P 1  by the adjustment of the opening of the valve  65   b  (Step S 26 ), the opening of the valve  65   a  is reduced. In a case where the flow ratio F is greater than F 1  by the adjustment of the opening of the valve  65   a  (Step S 24 ), the opening of the valve  65   b  is reduced. In a case where the flow ratio is less than F 1  by the adjustment of the opening of the valve  65   b  (Step S 24 ), the opening of the valve  65   b  is increased. Accordingly, by alternately adjusting the opening of the valves  65   a ,  65   b , each of the pressure P and the flow ratio F becomes closer to the corresponding predetermined values P 1 , F 1 . 
     In a case where the pressure P and the flow ratio F reach the predetermined value P 1 , F 1  by performing the steps S 24 -S 27 , the flow rate of the gas evacuated from the evacuation channels  63   a ,  63   b  become 20 sccm, 30 sccm, respectively. As illustrated in  FIG. 12B , each of the opening of the first valve  65   a  and the opening of the second valve  65   b  is set to, for example, A 2 , B 2 , respectively. Even in a case where time is up in Step S 28 , the amount of deviation between the adjusted pressure P and the predetermined value P 1  and the amount of deviation between the adjusted flow ratio F and the predetermined flow ratio F 1  becomes smaller as the aforementioned Steps S 24 -S 27  are repeated because the adjustment of the pressure P of the first pressure valve  65   a  and the adjustment of the pressure of the second pressure valve  65   b  are alternately performed. Accordingly, the pressure P and the flow ratio F are significantly close to the corresponding predetermined value P 1  and F 1  even when the time is up. Therefore, the operation proceeds to the film deposition process of Step S 14  even in the case where the time is up. 
     In order to maintain the pressure P and the flow ratio F set by performing the above-described steps, the opening of the first valve  65   a  and the opening of the second valve  65   b  are slightly adjusted. In this embodiment, a wide area is provided by cutting out (notching) the inner circumferential wall of the chamber body  12  provided at a lower side of the second ceiling surface  45 . The evacuation ports  61 ,  62  are provided below this wide space. Accordingly, the pressure in the space below the second ceiling surface  45  is lower than the pressure in the narrow space below the first ceiling surface  44  and lower than the pressure in the center portion area C. 
     Then, it is determined whether the temperature of the wafer W has reached a predetermined temperature by a temperature sensor (not illustrated) and whether the pressure P in the chamber  1  and the flow ratio F of the evacuation gases has stabilized to a steady state. Then, as  FIG. 14A  shows, the gases supplied from the first and second reaction nozzles  31 ,  32  are switched from N2 gas to BTBAS gas and O3 gas, respectively (Step S 14 ). As illustrated in  FIG. 14B , the gases are switched in a manner that the total flow rate of the gases supplied to the chamber  1  (gases supplied from the nozzles  31 ,  32 ) does not change. By switching the gases in this manner, change in the flow of gases applied to the wafer W as well as the pressure inside the chamber  1  can be restrained. Accordingly, as illustrated in  FIG. 12C , the pressure P inside the chamber  1  and the flow ratio F of evacuation gas can be maintained at predetermined values P 1  and F 1  without having to perform adjustment of the first and second valves  65   a ,  65   b  by performing the steps S 21 -S 28 . 
     Because the inside of the chamber  1  can be maintained at a steady state after gases are switched, the flow of gas with respect to an in-plane direction or in-between surfaces of the wafer W can be stabilized as illustrated in  FIG. 15 . Further, the flow of gas supplied to the wafer W during the film deposition process maintains a steady state because the opening of the valve  65   a ,  65   b  are slightly adjusted during the film deposition process in a manner that the flow ratio F of the gases evacuated from the evacuation channels  63   a ,  63   b  are maintained at the predetermined value F 1 . It is to be noted that the flow rate of each gas is schematically illustrated in  FIG. 14A . 
     Because the wafers W alternately pass through the first and second process areas  91 ,  92  by the rotation of the rotation table  2 , BTBAS gas is adsorbed to the wafer W and then O3 is adsorbed to the wafer W. Thereby, one or more layers of silicon oxide are formed on the wafer W. Accordingly, a silicon oxide film having a predetermined film thickness can be deposited by forming molecular layers of silicon oxide. 
     In this case, N2 gas is supplied between the first and second process areas  91 ,  92 . Further, N2 is also supplied to the center portion area C as separation gas. Further, the valve  65   a ,  65   b  are slightly adjusted so that the flow of gas supplied to the wafer W is stabilized. Accordingly, each of the BTBAS gas and the O3 gas can be evacuated so that the BTBAS gas and the O3 gas can be prevented from being mixed. Further, in the separation area(s), because the gap between the bent portion  46  and the outer edge surface of the rotation table  2  is narrow, the BTBAS gas and the O3 gas do not mix even via the outer side of the rotation table  2 . Therefore, the atmosphere of the first process area  91  and the atmosphere of the second process area  92  are substantially completely separated. Thus, the BTBAS gas is evacuated from the evacuation port  61  whereas the O3 gas is evacuated from the evacuation port  62 . As a result, the BTBAS gas and the O3 gas do not mix in both the atmospheres of the first and second process areas  91 ,  92  and on the surface of the wafers W. 
     In this embodiment, gas entering the evacuation area E can be prevented from passing under a lower part of the rotation table  2  because the lower part of the rotation table  2  is purged with N2 gas. Thus, for example, BTBAS gas can be prevented from entering the area where O3 gas is supplied. After the film deposition process is completed, the supply of gases are stopped and each wafer W is transferred outside in order by the transfer arm  10  (Step S 16 ). 
     An example of process parameters preferable in the film deposition apparatus according to this embodiment is listed below.
     rotational speed of the rotation table  2 : 1-500 rpm (in the case of the wafer W having a diameter of 300 mm)   flow rate of N2 gas from the separation gas pipe  51 : 5000 sccm   the number of rotations of the rotation table  2  (number of times in which the wafer W passes the process areas  91 ,  92 ): 600 rotations (depending on the film thickness required)   

     With the above-described embodiment, first and second process areas  91 ,  92  to which the reaction gases of BTSAS gases and O3 gases are supplied are formed in the same chamber in the rotation direction of the rotation table  2 . When forming a thin film by forming plural layers of reaction products by passing a wafer W through the first and second process chambers  91 ,  92  by rotating the rotation table  2 , separation gas is supplied to a separation area between the first and second process areas, separation areas D are provided between the first and second process chambers  91 ,  92  along with providing first and second evacuation channels  63   a ,  63   b  including evacuation ports  63   a ,  63   b  for separating and evacuating different reaction gases. The opening of the first valve  65   a  and the opening of the second valve  65   b  are adjusted so that the flow ratio F of the gases evacuated from the evacuation channels  63   a ,  63   b  becomes a predetermined value F 1 , and the pressure P inside the chamber  1  becomes P 1 . Therefore, the flow of gas on both sides of the separation areas can be stabilized. Thus, because the flow of the reaction gases (BATAS, O3) applied to the surface of the wafer W can be stabilized, the adsorption of BTBAS gas can be stabilized and the oxide reaction of the adsorbed molecules of O3 gas can be stabilized. As a result, the wafer W can obtain a satisfactory thin film having an even film thickness with respect to an in-plane direction or in-between surfaces of the wafer W. 
     Furthermore, because bias of evacuation on both sides of the separation areas D can be prevented, BTBAS gas and O3 gas can be prevented from passing through the separation areas and become mixed. Accordingly, reaction products can be prevented from being formed on areas besides the surface of the wafers W. Thus, formation of particles can be prevented. It is to be noted that the above-described embodiment of the present invention may be applied to a case where a single wafer is placed on the rotation table  2 . 
     In the above-described embodiment of the present invention, both the first and second valves  65   a ,  65   b  are fully evacuated in Step S 21 . Alternatively, in a case where the first valve  65   a  is adjusted in Step S 24 , the second valve  65   b  can have its opening adjusted in the same manner by calculating the opening of the second valve  65   b  and the flow rate of the gas evacuated from the second evacuation chamber  63   b . In this case, adjustment of the pressure value and adjustment of flow ratio can both be speedily performed. In this case, the pressure or the flow ratio that is adjusted becomes less (amount of change), and a reaction gas other than N2 gas may be used to adjust pressure or flow ratio. 
     In the above-described embodiment of the present invention, the flow rate of N2 gas when adjusting the pressure P or the flow ratio F is set to be substantially the same flow rate of the reaction gas when switching gases and performing film deposition. However, as long as the flow rate of N2 gas when adjusting the pressure P or the flow ratio F is near the flow rate of the reaction gas when switching gases and performing film deposition (e.g., ±5), turbulence of the gas applied to the wafer W can be suppressed. 
     In the above-described embodiment of the present invention, when time is up in Step S 28 , the operation proceeds to steps S 14  and thereafter is assumed that the pressure P and the flow ratio F are substantially close to corresponding predetermined values P 1 , F 1 . An alarm may be output for stopping a subsequent film deposition process. 
     Second Embodiment 
     In the first embodiment, the pressure in the chamber  1  and the flow ratio F of the evacuation channels  63   a ,  63   b  are controlled by relying only on the adjustments of the opening of the first and second valves  65   a ,  65   b . Alternatively, the control may be performed by further adding adjustment of the flow rate (evacuation performance) of the evacuation pump  64   b  by adjusting the number of rotations of the evacuation pump  64   b.    
     As illustrated in  FIG. 16 , the evacuation pump  64   b  is connected to an inverter  68  serving as a part for adjusting evacuation flow rate of the evacuation pump  64   b . The inverter  68  is configured to adjust the electric current flowing in the evacuation pump  64   b , that is the number of rotations (evacuation flow rate) of the evacuation pump  64   b . Accordingly, in this embodiment, the number of rotations R of the evacuation pump  64   b  is stored in correspondence with this recipe. It is to be noted that, components and effects of the film deposition apparatus according to this embodiment is substantially the same as the above-described embodiments of the present invention and further explanation thereof is omitted. 
     As illustrated in  FIG. 17 , in a case where the time is up after repeating the steps of controlling the pressure of the first valve  65   a  and controlling the flow rate of the second valve  65   b  (Step S 28 ), the third step of adjusting the number of rotations R of the evacuation pump  64   b  is performed (Step S 29 ). For example, after the flow ratio F is adjusted by the second valve  65   b  (Step S 26 ), the pressure P is determined (Step S 27 ). In a case where the pressure P is deviated from the predetermined value P 1 , the amount of evacuation of the evacuation pump  64   b  is adjusted so that the pressure P becomes the predetermined value P 1 . For example, in a case where the pressure is equal to or greater than the predetermined value P 1 , that is, in a case where the evacuation amount of the evacuation pump  64   b  is insufficient, the value of the electric current of the inverter  68  is set so that the evacuation amount of the evacuation pump  64   b  is increased by increasing the number of rotations R of the vacuum pump  64   b . On the other hand, in a case where the pressure P is less than the predetermined value P 1 , the evacuation amount of the evacuation pump  64   b  is reduced by reducing the number of rotations R of the evacuation pump  64   b.    
     Then, the above-described steps S 24 -S 27  are repeated after resetting the repetition time t 1  with the timer  86 . In a case where the pressure P and the flow ratio F are adjusted to the predetermined values P 1  and F 1  in Steps S 25  and S 27 , the operation proceeds to the film deposition process (Step S 14 ). In a case where the pressure P and the flow ratio F has not reached the predetermined values P 1  and F 1  even by the adjustment of the number of rotations R of the evacuation pump  64   b , adjustment of the number of rotations R of the evacuation pump  64   b  is repeated in Step S 29 . The steps S 24 -S 28  are repeated until the repetition time t 1  elapses or the pressure P and the flow ratio F reach the predetermined values P 1  and F 1 . It is to be noted that even in a case where the pressure P and the flow ratio F has not reached the predetermined values P 1  and F 1  after the elapse of the repetition time t 1 , the adjusted pressure P and the adjusted flow ratio F become closer towards corresponding predetermined values P 1  and F 1  becomes smaller because the opening of the valves  65   a ,  65   b  and the number of rotations R of the evacuation pump  64   b  are adjusted. Accordingly, the pressure P and the flow ratio F become close to the predetermined values P 1  and the flow ratio F even when the time is up. Thus, the operation proceeds to the film deposition process of Step S 14  even in the case where the time is up. 
     With the above-described embodiment of the present invention, the following effect can be obtained. That is, even in a case where the pressure P and the flow ratio F cannot be adjusted to the predetermined values P 1  and F 1  within the repetition time (t 1 ) by adjusting the opening of the first and second valves  65   a ,  65   b , the opening of the first and second valves  65   a ,  65   b  can be re-adjusted by adjusting the number of rotations R of the evacuation pump  64   b . Therefore, even if there is a difference in the evacuation performance between the evacuation pumps  64   a ,  64   b , the pressure P and the flow ratio F can be set to become the predetermined values P 1  and F 1 . In other words, by adjusting the number of rotations R of the evacuation pump  64   b  along with adjusting the opening of the valves  65   a ,  65   b , the pressure P and the flow ratio F can be set in a wide range. 
     In the above-described embodiment, the number of rotations R of the evacuation pump  64   b  is adjusted. Alternatively, the evacuation pump  64   a  may be connected to the inverter so that the number of rotation of the evacuation pump  64   a  is adjusted instead of the evacuation pump  64   b . Alternatively, the number of rotations of both the evacuation pumps  64   a  and  64   b  may be adjusted. In a case of adjusting the number of rotations R of both the evacuation pumps  64   a  and  64   b , the number of rotations R of both the evacuation pumps  64   a  and  64   b  may be adjusted simultaneously in Step S 29 . Alternatively, in a case of adjusting the number of rotations R of both the evacuation pumps  64   a  and  64   b , the number of rotations R of the evacuation pump  64   b  is adjusted in Step S 29 , then the number of rotations R of the evacuation pump  64   a  is adjusted after the time is up in Step S 28 , then the repetition time t 1  is set in Step S 23 , and then the opening of the valves  65   a ,  65   b  are adjusted in Steps S 24 -S 28 . 
     In the above-described embodiment, the step S 29  is performed when the time is up in Step S 28 . Alternatively, the step S 29  may be performed between steps S 27  and S 28 , so that the adjustment of the opening of the valves  65   a ,  65   b  is repeated along with the adjustment of the number of rotations R of the evacuation pump  64   a , for example. Further, in the step S 27  (before repeating each step), the step S 29  may be performed before repeating the steps S 24 -S 27  in a case where, for example, the pressure P is significantly deviates from the predetermined value P 1 . 
     In the above-described embodiment, generation of reaction products inside the evacuation passages  63   a ,  63   b  and the evacuation pump  64  is prevented by separately evacuating the reaction gases from two evacuation passages  63   a ,  63   b . In a case where reaction of reaction gases is unlikely to occur where the temperature inside the evacuation passages  63   a ,  63   b  and the evacuation pump  64  is low, the evacuation pumps  64   a ,  64   b  may be formed into a shared evacuation pump  64  as illustrated in  FIG. 18 . In this case, the cost of the film deposition apparatus can be reduced. 
     As for process gases that are used in the present invention other than those of the above-described embodiments of the present invention, there are dichlorosilane (DCS), hexachlorodisilane (HCD), Trimethyl Aluminum (TMA), tris(dimethyl amino) silane (3DMAS), tetrakis-ethyl-methyl-amino-zirconium (TEMAZr), tetrakis-ethyl-methyl-amino-hafnium (TEMHf), bis(tetra methyl heptandionate) strontium (Sr(THD) 2 ), (methyl-pentadionate)(bis-tetra-methyl-heptandionate) titanium (Ti(MPD)(THD)), monoamino-silane, or the like. 
     Because gas flows toward the separation area D at a higher speed in the position closer to the outer circumference of the rotation table  2 , it is preferable that the width of an upstream area of the ceiling surface  44  of the separation area D with respect to the separation gas nozzles  41 ,  42  to be greater than the area located at the outer circumference of the rotation table  2 . In view of this, it is preferable for the convex portion  4  to have a sector-shape. 
     As illustrated in  FIGS. 19A and 19B , in a case where a wafer W having a diameter of, for example, 300 mm is used as the target substrate, the ceiling surface  44  that creates the thin space in both sides of the separation gas nozzle  41  is preferred to have a width L equal to or greater than 50 mm in the rotation direction of the rotation table  2  at a portion where the center WO of the wafer W passes. In order to effectively prevent reaction gases from entering an area below the convex portion  4  from both sides of the convex portion  4 , the distance h between the first ceiling surface  44  and the rotation table  2  is made to be short in a case where the width L is small. Further, in a case where a predetermined length is set to the distance h between the first ceiling surface  44  and the rotation table  2 , the speed of the rotation table  2  becomes faster the farther away from the rotation center of the rotation table  2 . Therefore, the width L required for attaining a reaction gas impeding effect becomes greater the farther away from the rotation center. When the width L is small, the height h of the thin space between the ceiling surface  44  and the rotation table  2  (wafer W) has to be made accordingly small in order to effectively prevent the reaction gases from flowing into the thin space. It is, therefore, necessary to reduce the vibration of the rotation table  2  as much as possible for preventing collision between the rotation table  2  or the wafer W and the ceiling surface  44  when the rotation table  2  is rotated. Further, it becomes easier for reactions gases to enter the lower part of the convex portion  4  from upstream of the convex portion  4  as the number of rotations of the rotation table  2  increases. Thus, when the width L is less than 50 mm, it becomes necessary to reduce the number of rotations of the rotation table  2  which is rather disadvantageous in terms of production throughput. Therefore, it is preferable for the width L to be equal to or greater than 50 mm. Nevertheless, the effects of the present invention may still be attained where the width L is equal to or less than 50 mm. In other words, it is preferable for the width L to be 1/10- 1/1 compared to the diameter of the wafer W, and more preferably about ⅙ or greater than the diameter of the wafer W. 
     The separation gas nozzle  41  ( 42 ) is located in the groove portion  43  formed in the convex portion  4  and the lower ceiling surfaces  44  are located in both sides of the separation gas nozzle  41  ( 42 ) in the above embodiment. However, as shown in  FIG. 20 , a conduit  47  extending along the radial direction of the rotation table  2  may be made inside the convex portion  4 , instead of the separation gas nozzle  41  ( 42 ), and plural holes  40  may be formed along the longitudinal direction of the conduit  47  so that the separation gas (N2 gas) may be ejected from the plural holes  40  in other embodiments. 
     As illustrated in  FIG. 21A , the ceiling surface  44  of the separation areas D may not only be formed as a flat surface but may also be formed as a recess, a protrusion as illustrated in  FIG. 21B , or a wave-shape as illustrated in  FIG. 21C . 
     The heating part for heating the wafer W may not only be a heater having a resistance heating element but may also be a lamp heating element. In addition, the heater unit  7  may be located above the rotation table  2 , or above and below the rotation table  2 . Further, in a case where the reaction of the reaction gases occur at a low temperature (e.g., room temperature), no heating member need to be provided. 
     Examples of the layout of the process areas  91 ,  92  and the separation areas D other than the above-described embodiments of the present invention are described below.  FIG. 22  illustrates an example where the second reaction nozzle  32  is positioned upstream from the transfer opening  15  with respect to the rotation direction of the rotation table  2 . The same effect as the above-described embodiments of the present invention can be attained even with this layout. The separation areas D may be configured having the sector-shaped convex portion  4  divided into two sector-shaped convex portions in the circumferential direction with the separation gas nozzle  41  ( 42 ) provided therebetween.  FIG. 23  illustrates a plan view of this configuration. In this case, for example, the distance between the sector-shaped convex portion  4  and the separation gas nozzle  41  ( 42 ) or the size of the sector-shaped convex portion  4  may be set to enable the separation areas D to effectively exhibit a separating effect taking the ejection flow rate of the separation gas or the ejection flow rate of the reaction gas. 
     In the above-described embodiment of the present invention, the first and second process areas  91  and  92  correspond to an area having a ceiling surface higher than the ceiling surface of the separation area D. However, in this embodiment, at least one of the first and second process areas  91  and  92  has ceiling surfaces that face the rotation table  2  on both sides of the gas supplying part relative to the rotation direction in the same manner as the separation area D to form a space for impeding gas from entering the space between the ceiling surfaces and the rotation table  2  and these ceiling surfaces are lower than the ceiling surfaces (second ceiling surfaces) on both sides of the separation area D relative to the rotation direction.  FIG. 24  illustrates an example of this configuration. In the second process area  92  (in this example, adsorption area of O3 gas), the second reaction gas nozzle  32  is provided below the sector shaped convex portion  4 . Other than providing the second reaction gas nozzle instead of the separation gas nozzle  41  ( 42 ), the second process area  92  in this embodiment is substantially the same as the separation area D. 
     In this embodiment, as illustrated in  FIG. 25 , in addition to providing low ceiling surfaces (first ceiling surfaces)  44  on both sides of the separation gas nozzle  41  ( 42 ) for forming narrow gaps, low ceiling surfaces are also provided on both sides of the reaction gas nozzle  31  ( 32 ), so that the ceiling surfaces are formed to be continuous. In other words, even in a case where the convex portion  4  is provided to the entire area facing the rotation table  2 , the same effect can be attained except at the areas other than the areas where the separation gas nozzle  41  ( 42 ) and the reaction gas nozzle  31  ( 32 ) are provided. From a different standpoint, this configuration has the first ceiling surfaces  44  on both sides of the separation gas nozzle  41  ( 42 ) extending to the reaction gas nozzle  31  ( 32 ). In this case, although the separation gas diffusing to both sides of the separation nozzle  41  ( 42 ) and separation gas diffusing to both sides of the reaction gas nozzle  31  ( 32 ) merge at a lower part of the convex portion  4  (narrow gap), the gases are evacuated from the evacuation port  61  ( 62 ) positioned between the separation gas nozzle  42  ( 41 ) and the reaction gas nozzle  31  ( 32 ). 
     In the above embodiments, the rotation shaft  22  for rotating the rotation table  2  is located in the center portion of the chamber  1 . In the above-described embodiment of the present invention, the space between the core portion  21  of the rotation table  2  and the ceiling plate  11  of the chamber  1  is purged with the separation gas. However, the chamber  1  may be configured as illustrated in  FIG. 26 . In the film deposition apparatus of  FIG. 26 , the bottom portion  14  of the chamber body  12  includes a housing space  100  of a driving portion and a concave portion  100   a  formed on the upper surface of the center portion of the chamber  1 . A pillar  101  is placed between the bottom surface of the housing space  100  and the upper surface of the concave part  100   a  at the center portion of the chamber  1  for preventing the first reaction gas (BTBAS) ejected from the first reaction gas nozzle  31  and the second reaction gas (O3) ejected from the second reaction gas nozzle  32  from being mixed through the center portion of the chamber  1 . 
     In addition, a rotation sleeve  102  is provided so that the rotation sleeve  102  coaxially surrounds the pillar  101 . A ring-shape rotation table  2  is provided along the rotation sleeve  102 . Further, a driving gear portion  104 , which is driven by a motor  103 , is provided in the housing space  100 . The rotation sleeve  102  is rotated by the driving gear portion  104  via a gear portion  105  formed on the outer surface of the rotation sleeve  82 . Reference numerals  106 ,  107 , and  108  indicate bearings. A purge gas supplying pipe  74  is connected to a bottom part of the housing space  100 , so that a purge gas is supplied into the housing space  100 . Another purge gas supplying pipe  75  is connected to an upper part of the housing space  100 , so that a purge gas is supplied between a side surface of the concave portion  100   a  and an upper edge part of the rotation sleeve  102 . Although opening parts for supplying the purge gas to the space between the side surface of the concave portion  100   a  and the upper edge part of the rotation sleeve  102  are illustrated in a manner provided on two areas (one on the left and one on the right) in  FIG. 26 , the number of the opening parts (purge gas supplying port) may be determined so that the purge gas from the BTBAS gas and the O3 gas in the vicinity of the rotation sleeve  102  can be prevented from being mixed. 
     In the embodiment illustrated in  FIG. 26 , a space between the side wall of the concave portion  80   a  and the upper end portion of the rotation sleeve  82  corresponds to the ejection hole for ejecting the separation gas. Thus, in this embodiment, the ejection hole, the rotation sleeve  102 , and the pillar  101  constitute the center portion area provided at a center part of the chamber  1 . 
     Although the two kinds of reaction gases are used in the film deposition apparatus according to the above embodiment, three or more kinds of reaction gases may be used in other film deposition apparatuses according to other embodiments of the present invention. In this case, a first reaction gas nozzle, a separation gas nozzle, a second reaction gas nozzle, a separation gas nozzle, and a third reaction gas nozzle may be arranged in this order relative to the circumferential direction of the chamber  1 , and the separation areas including respective separation nozzles may have the same configuration as those in the above-described embodiments. In this case, an evacuation channel, a pressure gage, and/or a valve may be provided in communication with each process chamber, to thereby perform the above-described adjustment of the evacuation flow rate (pressure difference between front and rear valves) in each process area. 
     The film deposition apparatus according to embodiments of the present invention may be integrated into a wafer process apparatus, an example of which is schematically illustrated in  FIG. 27 . The wafer process apparatus includes an atmospheric transfer chamber  112  in which a transfer arm  113  is provided, load lock chambers (preparation chambers)  114 ,  115  whose atmosphere is changeable between vacuum and atmospheric pressure, a vacuum transfer chamber  116  in which two transfer arms  107   a ,  107   b  are provided, and film deposition apparatuses  118 ,  119  according to embodiments of the present invention. In addition, the wafer process apparatus includes cassette stages (not shown) on which a wafer cassette  111  is placed. The wafer cassette  111  is brought onto one of the cassette stages, and connected to a transfer in/out port provided between the cassette stage and the atmospheric transfer chamber  112 . Then, a lid of the wafer cassette  111  is opened by an opening/closing mechanism (not shown) and the wafer is taken out from the wafer cassette  111  by the transfer arm  117 . Next, the wafer is transferred to the load lock chamber  114  ( 115 ). After the load lock chamber  114  ( 115 ) is evacuated, the wafer in the load lock chamber  114  ( 115 ) is transferred further to one of the film deposition apparatuses  118 ,  119  through the vacuum transfer chamber  117  by the transfer arm  107   a  ( 107   b ). In the film deposition apparatus  118  ( 119 ), a film is deposited on the wafer in such a manner as described above. Because the wafer process apparatus has two film deposition apparatuses  118 ,  119  that can house five wafers at a time, the ALD (or MLD) mode deposition can be performed at high throughput. 
     In the above-described embodiments of the present invention, in stabilizing the flow of each reaction gas in the chamber  1 , the openings of the first and second valves  65   a ,  65   b  provided in the evacuation channels  63   a ,  63   b  are adjusted so that, for example, the flow ratio F of the evacuation gas flowing inside the two evacuation channels  63   a ,  63   b  is equal. Alternatively, the opening of the first and second valves  65   a ,  65   b  may be adjusted so that the pressure difference between each of the process areas  91 ,  92  becomes smaller. In this case, a film deposition apparatus and a film deposition method are described with reference to  FIGS. 28-31 . In the below-described embodiments, like components are denoted by like reference numerals as for the above-described embodiments and are not further explained. 
     In this embodiment, as illustrated in  FIG. 28 , the first and second process pressure detecting parts  66   a ,  66   b  provided in the evacuation channels  63   a ,  63   b  are for measuring the pressure of the first and second process areas  91 ,  92 . In this embodiment, the first and second pressure detecting parts  67   a ,  67   b  do not need to be provided in the evacuation channels  63   a ,  63   b.    
     As illustrated in  FIG. 29 , instead of storing the gas flow ratio F, the pressure difference ΔP allowed between the first and second process areas  91 ,  92  is stored in the memory  82  in correspondence with each recipe. In other words, in a case where the pressure difference ΔP between each process area  91 ,  92  in the chamber  1  is large, the flow of gas may become unstable because reaction gas tends to flow from a high pressure area to a low pressure area via the separation area D between the process areas  91 ,  92 . However, in this embodiment, the flow of gas is stabilized by restraining the pressure difference ΔP between each process area  91 ,  92  to a small amount. 
     In this embodiment, in order to stabilize the flow of gas, the opening of the first and second valves  65   a ,  65   b  using nitrogen gas is adjusted before the supplying of reaction gas (Step S 13 ) as illustrated in  FIG. 30 . The differences in the method of stabilizing the flow of gas or the conditions of processing with respect to the first embodiment are described below with reference to  FIG. 31 . In step S 22 ′, the predetermined value P 1  of pressure P and a predetermined value ΔP 1  of the pressure difference ΔP between the first and second process areas  91 ,  92  are set to be, for example, 1067 Pa (8 Torr) and 13.3 Pa (0.1 Torr) respectively. Then, in step S 24 , the process pressure inside the chamber  1  is adjusted by adjusting the opening of the first valve  65   a  so that the value detected by the process pressure detecting part  66   a  becomes the predetermined value P 1 . Then, in step S 25 ′, it is determined whether the pressure difference ΔP is equal to or less than the predetermined value P 1  according to the measured (detected) results of the process pressure detecting parts  66   a ,  66   b . In a case where the pressure difference ΔP becomes equal to or less than the predetermined value P 1 , the operation proceeds to the film deposition process of step S 14 . In a case where the pressure difference ΔP is greater than ΔP 1 , the opening of the second valve  65   b  is adjusted so that the pressure difference ΔP becomes equal to or less than the predetermined value ΔP 1  (Step S 26 ). Then, in a case where the process pressure becomes the predetermined value P 1 , the thin film deposition is initiated (Step S 27 ). In a case where the process pressure does not become the predetermined value P 1 , the processes of steps S 24 -S 27  are repeated when the repletion time t 1  elapses (Step S 28 ), when the pressure difference ΔP becomes equal to or less than the predetermined value P 1  in Step S 25 , or when the process pressure reaches the predetermined value P 1  in Step S 27 . 
     Then, in performing the film deposition process where gas is switched from N2 gas to reaction gas, the flow of gas (BTBAS gas, O3 gas) becomes stable owing to the pressure difference ΔP between the process areas  91 ,  92  being equal to or less than the predetermined value ΔP 1  by the step S 21 -S 28  or the pressure difference ΔP between the process areas  91 ,  92  being substantially close to the predetermined value ΔP 1 . Therefore, the adsorption of BTBAS gas can be stabilized and the oxide reaction of the adsorbed molecules of O3 gas can be stabilized. As a result, the wafer W can obtain a satisfactory thin film having an even film thickness with respect to an in-plane direction or in-between surfaces of the wafer W. 
     Furthermore, because bias of evacuation on both sides of the separation areas D can be prevented, BTBAS gas and O3 gas can be prevented from passing through the separation areas and become mixed. Accordingly, reaction products can be prevented from being formed on areas besides the surface of the wafers W. Thus, formation of particles can be prevented. Further, because the pressure difference ΔP between the first and second process chambers  91 ,  92  can be reduced to a low value, a buoyancy of gases rising from the rotation table  2  hardly occurs, for example, when the wafer W enters the process area  91  ( 92 ) or when the wafer W exits the process area  91  ( 92 ) by the rotation of the rotation table  2 . Accordingly, the wafer W can be prevented from floating from the concave portion  24  or deviating from the concave portion  24 . Thus, the wafer W can be prevented from colliding with the ceiling plate  11  and problems can be prevented from occurring in the film deposition process. 
     Further, even in a case where there is difference in the gas flow (conductance) between the first and second process areas  91 ,  92  due to the size difference between the areas (first and second process areas  91 ,  92 ) in which the gases flow or influence the concave portion  24  formed in the rotation table  2 , the difference in the conductance of the gas flow can be restrained and the flow of gas can be positively stabilized because the pressure difference ΔP between the first and second process areas  91 ,  92  is restrained to a low value. 
     In the above-described embodiments of the present invention, in measuring (detecting) the pressure of the first and second process areas  91 ,  92 , the process pressure detecting parts  66   a ,  66   b  are provided to the evacuation channels  63   a ,  63   b . Alternatively, the process pressure detecting parts  66   a ,  66   b  in other areas pressure communicating with the first and second process areas  91 ,  92  (e.g., sidewall of the chamber  1 ). Further, in adjusting the pressure of each process area  91 ,  92 , the number of rotations R of the evacuation pump  64  may be adjusted along with adjusting the opening of the first and second valves  65   a ,  65   b . Further, the two evacuation pumps  64   a  and  64   b  may be shared (integrated). Further, although the pressure detection value of the process pressure detecting part  66   a  is used in setting the process pressure in the chamber  1  to the predetermined value P 1  according to the above-described embodiments of the present invention, the pressure detection value of the process pressure detecting part  66   a  may alternatively be used. Further, a pressure value detected from another pressure detecting part provided in the chamber  1  may serve as the pressure value used to set the process pressure in the chamber  1  to the predetermined value P 1 . 
     In the above-described embodiments, the pressure of the first and second process areas  91 ,  92  are adjusted instead of the flow ratio F of the evacuation gas for stabilizing gas flow. However, both the flow rate of the evacuation gas and the pressure of the first and second process areas  91 ,  92  may be adjusted. For example, in a case where there is a high possibility of pressure changing inside the chamber  1 , pressure in each process area  91 ,  92  is adjusted when starting the supply of reaction gas into the chamber  1  (when switching from N2 gas to reaction gas in Step S 14  and then, the flow ratio F of the evacuation gas is adjusted when a predetermined time elapses after starting a film deposition process. In this case, the flow of gas flowing into the chamber  1  can be further stabilized and the buoyancy of the wafer W can be restrained. 
     Third Embodiment 
     In the following embodiment of the present invention, a vacuum chamber having a rotation table includes a first process area to which a first reaction gas is supplied and a second process area in which a second reaction gas is supplied. Further, the first and second process areas are separated from each other in a rotation direction of the rotation table. Further, separation areas are interposed between the first and second process areas for supplying separation gas between the first and second process areas from a separation gas supplying part. A thin film deposition process is performed by rotating a rotation table having plural substrates arranged in a rotation direction and layering plural layers of reaction products with first and second reaction gases. Evacuation is performed with a first evacuation channel having an evacuation port positioned between the first process area and the separation area positioned adjacent to the first process area and located downstream of the first process area relative to the rotation direction when viewed from the rotation center of the rotation table and a second evacuation channel having an evacuation port positioned between the second process area and the separation area positioned adjacent to the second process area and located downstream of the second process area relative to the rotation direction when viewed from the rotation center of the rotation table. The evacuation system (evacuation channel, pressure control device, evacuation part) of each of the process areas is independent from the other. Accordingly, in performing the thin film deposition process, the first and second reaction gases do not mix in the evacuation systems. Therefore, the possibility of reaction products being generated in the evacuation systems is extremely low. 
     Further, a ceiling surface is provided on both sides of a separation gas supplying part for forming a narrow space that allows the separation gas to flow from the separation areas towards the process areas. Thereby, reaction gases are prevented from entering separation areas. Further, a center portion area, which is positioned at a center portion inside the chamber for separating the atmosphere of the first and second process areas, includes an ejection port that ejects separation gas towards a substrate receiving surface of the rotation table for ejecting the separation gas towards the circumferential edges of the rotation table. As a result, with the center portion area disposed in-between, different reaction gases can be prevented from mixing with each other. Accordingly, a satisfactory film deposition process can be achieved. Further, generation of particles can be prevented because no reaction products or very few reaction products are formed. 
     Referring to  FIG. 32 , which is a cut-away diagram taken along I-I′ line in  FIG. 34 , a film deposition apparatus according to an embodiment of the present invention has a vacuum chamber  201  having a flattened cylinder shape, and a rotation table  202  that is located inside the chamber  201  and has a rotation center at a center of the vacuum chamber  201 . The vacuum chamber  201  is made so that a ceiling plate  211  can be separated from a chamber body  212 . The ceiling plate  211  is pressed onto the chamber body  212  via a ceiling member such as an O-ring  213 , so that the vacuum chamber  201  is hermetically sealed. On the other hand, the ceiling plate  211  can be raised by a driving mechanism (not shown) when the ceiling plate  211  has to be removed from the chamber body  212 . 
     The rotation table  202  is fixed onto a cylindrically shaped core portion  221 . The core portion  221  is fixed on a top end of a rotational shaft  222  that extends in a vertical direction. The rotational shaft  222  penetrates a bottom portion  214  of the vacuum chamber  201  and is fixed at the lower end to a driving mechanism  223  that can rotate the rotational shaft  222  clockwise, in this embodiment. The rotation shaft  222  and the driving mechanism  223  are housed in a cylindrical case body  220  having an open upper surface. The case body  220  is hermetically fixed to a bottom surface of the bottom portion  214  via a flanged portion, which isolates an inner environment of the case body  220  from an outer environment. 
     As shown in  FIGS. 33 and 34 , plural (five in the illustrated example) circular concave portions  224 , each of which receives a semiconductor wafer W, are formed along a rotation direction (circumferential direction) in a top surface of the rotation table  202 , although only one wafer W is illustrated in  FIG. 34 .  FIGS. 35A and 35B  are expanded views of the rotation table  202  being cut across and horizontally expanded along its concentric circle. As shown in  FIG. 35A , the concave portion  224  has a diameter slightly larger, for example, by 4 mm than the diameter of the wafer W and a depth equal to a thickness of the wafer W. Therefore, when the wafer W is placed in the concave portion  224 , a surface of the wafer W is at the same elevation of a surface of the rotation table  202  (an area of the rotation table where the wafer W is not placed). If there is a relatively large difference in height between the surface of the wafer W and the surface of the rotation table  202 , a change of pressure occurs at the portion where the difference is located. Therefore, from the aspect of attaining uniformity of film thickness in the in-plane direction, it is preferable to match the elevation of the surface of the wafer W and the elevation of the surface of the rotation table  202 . While matching the elevation of the surface of the wafer W and the height of the surface of the rotation table  202  may signify that the height difference of the surfaces of the wafer W and the rotation table is less than or equal to approximately 5 mm, the difference has to be as close to zero as possible to the extent allowed by machining accuracy. In the bottom of the concave portion  224  there are formed three through holes (not shown) through which three corresponding elevation pins are raised/lowered. The elevation pins support a back surface of the wafer W and raises/lowers the wafer W. 
     The concave portions  224  are substrate receiving areas (wafer W receiving areas) provided to position the wafers W and prevent the wafers W from being thrown outwardly by the centrifugal force caused by rotation of the rotation table  202 . However, the wafer W receiving areas are not limited to the concave portions  224 , but may be performed by guide members that are provided along a circumferential direction on the surface of the rotation table  202  to hold the edges of the wafers W. In a case where the rotation table  202  is provided with a chuck mechanism (e.g., electrostatic chucks) for attracting the wafer W, the areas on which the wafers W are received by the attraction serve as the substrate receiving areas. 
     Referring again to  FIGS. 33 and 34 , the chamber  201  includes a first reaction gas nozzle  231 , a second reaction gas nozzle  232 , and separation gas nozzles  241 ,  242  above the rotation table  202 , all of which extend in radial directions and are arranged at predetermined angular intervals in a circumferential direction of the chamber  201 . With this configuration, the concave portions  224  can move through and below the nozzles  231 ,  232 ,  241 , and  242 . In the illustrated example, the second reaction gas nozzle  232 , the separation gas nozzle  241 , the first reaction gas nozzle  231 , and the separation gas nozzle  242  are arranged clockwise in this order. These gas nozzles  231 ,  232 ,  241 , and  242  penetrate the circumferential wall portion of the chamber body  212  and are supported by attaching their base ends, which are gas inlet ports  231   a ,  232   a ,  241   a ,  242   a , respectively, on the outer circumference of the wall portion. 
     Although the gas nozzles  231 ,  232 ,  241 ,  242  are introduced into the chamber  201  from the circumferential wall portion of the chamber  201  in the illustrated example, these nozzles  231 ,  232 ,  241 ,  242  may be introduced from a ring-shaped protrusion portion  205  (described later). In this case, an L-shaped conduit may be provided in order to be open on the outer circumferential surface of the protrusion portion  205  and on the outer top surface of the ceiling plate  211 . With such an L-shaped conduit, the nozzle  231  ( 232 ,  241 ,  242 ) can be connected to one opening of the L-shaped conduit inside the chamber  201  and the gas inlet port  231   a  ( 232   a ,  241   a ,  242   a ) can be connected to the other opening of the L-shaped conduit outside the chamber  201 . 
     The reaction gas nozzle  231  is connected to a gas supply source (not illustrated) of a first reaction gas (e.g., BTBAS gas) and the reaction gas nozzle  232  is connected to a gas supply source (not illustrated) of a second reaction gas (e.g., O3 gas). Further, the reaction gas nozzles  241  and  242  are each connected to a gas supply source (not illustrated) of N2 gas. Further, the reaction gas nozzles  231 ,  232  are also connected to a gas supply source (not illustrated) of N2 for supplying N2 gas to each process area  200 P 1 ,  200 P 2  as a pressure adjustment gas when operation of the film deposition apparatus is initiated. In this embodiment, the second reaction gas nozzle  232 , the separation gas nozzle  241 , the first reaction gas nozzle  231 , and the separation gas nozzle  242  are arranged in this order in a clockwise direction. 
     The reaction gas nozzles  231 ,  232  have ejection holes  233  facing directly downward for ejecting reaction gases below. The ejection holes  233  are arranged at predetermined intervals in longitudinal directions of the reaction gas nozzles  231 ,  232 . The separation gas nozzles  241 ,  242  have ejection holes  240  facing directly downward for ejecting reaction gases below. The ejection holes  233  are arranged at predetermined intervals in longitudinal directions of the reaction gas nozzles  231 ,  232 . The reaction gas nozzle  231  corresponds to a first reaction gas supplying part and the reaction gas nozzle  232  corresponds to a second reaction gas supplying part. The area below the first reaction gas supplying part corresponds to a first process area  200 P 1  for enabling BTBAS gas to be adsorbed to the wafer W. The area below the second reaction gas supplying part corresponds to a second process area  200 P 2  for enabling O3 gas to be adsorbed to the wafer W. 
     The separation gas nozzles  241 ,  242  are provided in separation areas  200 D that are configured to separate the first process area  200 P 1  and the second process area  200 P 2 . As shown in  FIGS. 33 through 35B , in each of the separation areas  200 D, a convex portion  204  is provided in a ceiling plate  211  of the chamber  201  in a manner protruding downwards. The convex portion  204  has a top view shape of a sector. The convex portion  204  is formed by dividing a circle depicted along an inner circumferential wall of the chamber  201 . The circle has the rotation center of the rotation table  202  as its center. The convex portion  204  has a groove portion  243  provided at the circumferential center of the circle that extends in the radial direction of the circle. The separation gas nozzle  241  ( 242 ) is located in the groove portion  243 . The distance between the center axis of the separation gas nozzle  241  ( 242 ) and one side of the sector-shaped convex portion  204  (edge of the convex portion  204  towards an upstream side relative to relative to a rotation direction of the rotation table  202 ) is substantially equal to the distance between the center axis of the separation gas nozzle  241  ( 242 ) and the other side (edge of the convex portion  204  towards a downstream side relative to the rotation direction of the rotation table  202 ) of the sector-shaped convex portion  204 . 
     It is to be noted that, although the groove portion  243  is formed in a manner bisecting the convex portion  204  in this embodiment, the groove portion  242  may be formed so that an upstream side of the convex portion  204  relative to the rotation direction of the rotation table  202  is wider, in other embodiments. 
     Accordingly, in this embodiment, a flat low ceiling surface (first ceiling surface)  244  is provided as a lower surface of the convex portion  204  on both sides of the separation gas nozzle  241  ( 242 ) relative to the rotation direction of the rotation table  202 . Further, a high ceiling surface (second ceiling surface)  245 , which is positioned higher than the first ceiling surface  244 , is provided on both sides of the separation gas nozzle  241  ( 242 ) relative to the rotation direction of the rotation table  202 . The role of the convex portion  204  is to provide a separation space which is a narrow space between the convex portion  204  and the rotation table  202  for impeding the first and second reaction gases from entering the narrow space and preventing the first and second reaction gases from being mixed. 
     Taking the separation gas nozzle  241  as an example, the O3 gas from an upstream side of the rotation direction of the rotation table  202  is impeded from entering the space between the convex portion  204  and the rotation table  202 . Further, the BTBAS gas from a downstream side of the rotation direction of the rotation table  202  is impeded from entering the space between the convex portion  204  and the rotation table  202 . “Impeding the first and second reaction gases from entering” signifies that the N2 gas ejected as the separation gas from the separation gas nozzle  241  diffuses between the first ceiling surfaces  244  and the upper surfaces of the rotation table  202  and flows out to a space below the second ceiling surfaces  245 , which are adjacent to the corresponding first ceiling surfaces  244  in the illustrated example, so that the gases cannot enter the separation space from the space below the second ceiling surfaces  245 . “The gases cannot enter the separation space” not only signifies that the gases from the adjacent space below the second ceiling surfaces  245  are completely prevented from entering the space below the convex portion  204 , but that the gases from both sides cannot proceed farther toward the space below the convex portion  204  and thus be mixed with each other. Namely, as long as such effect can be attained, the separation area  200 D can achieve the role of separating the first process area  291  and the second process area  292 . The narrowness of the narrow space is set so that the pressure difference between the narrow space (space below the convex portion  204 ) and the space adjacent to the narrow space (e.g., space below the second ceiling surface  245 ) is large enough to attain the effect of “the gases cannot enter the separation space”. The specific measurements of the narrow space differs depending on, for example, the area of the convex portion  204 . Further, the gases adsorbed on the wafer W can pass through below the convex portion  204 . Therefore, “impeding the first and second reaction gases from entering” signifies that the first and second reaction gases are in a gaseous phase. 
     As illustrated in  FIGS. 36 and 38 , a protrusion portion  205  is provided on a lower surface of the ceiling plate  211  so that the inner circumference of the protrusion portion  205  faces the outer circumference of the core portion  221 . The protrusion portion  205  opposes the rotation table  202  at an outer area of the core portion  221 . In addition, a lower surface of the protrusion portion  205  and a lower surface of the convex portion  204  form one plane surface. In other words, a height of the lower surface of the protrusion portion  205  from the rotation table  202  is the same as a height of the lower surface (ceiling surface  244 ) of the convex portion  204 .  FIGS. 33 and 34  show the ceiling plate  211  being horizontally cut across an area including a portion substantially lower than the ceiling surface  245  but higher than the separation nozzles  241 ,  242 . The convex portion  204  may not only be formed integrally with the protrusion portion  205  but may also be formed separately from the protrusion portion  205 . 
     The configuration of the combination of the convex portion  204  and the separation nozzle  241  ( 242 ) is fabricated by forming the groove portion  243  in a sector-shaped plate to be the convex portion  204 , and locating the separation gas nozzle  241  ( 242 ) in the groove portion  243  in the above embodiment. However, two sector-shaped plates may be attached on the lower surface of the ceiling plate  211  by screws so that the two sector-shaped plates are located on both sides of the separation gas nozzle  241  ( 242 ). 
     In this embodiment, the separation gas nozzles  241  ( 242 ) has ejection holes arranged at predetermined intervals (e.g., about 10 mm) in longitudinal directions of the separation gas nozzles  241 ,  242 . The ejection holes have an inner diameter of about 0.5 mm, for example. 
     In this embodiment, a wafer W having a diameter of about 300 mm is used as the target substrate. In this embodiment, at an area spaced about 140 mm from the rotation center of the rotation table  202  in the outer circumferential direction (border part between the convex portion  204  and the below-described convex portion  205 ), the convex portion  204  includes a part where the length is about 146 mm in the circumferential direction (length of arc concentric with the rotation table  202 ). Further, at an area corresponding to an outermost part of the wafer W receiving area (concave part  224 ), the convex portion includes a part where the length is about 502 mm in the circumferential direction. In the outermost part as illustrated in  FIG. 35A , the length L of convex portion  204  on each side of the separation nozzle  241  ( 42 ) with respect to the circumferential direction is about 246 mm. 
     As illustrated in  FIG. 35B , the height from a top surface of the rotation table  202  to the lower surface of the convex portion  204  (i.e. first ceiling surface  244 ) is indicated as “h”. The height h ranges from, for example, about 0.5 mm to 10 mm, and more preferably, about 4 mm. In this case, the number of rotations of the rotation table  202  is set to, for example, about 1 rpm-500 rpm. Accordingly, in order to attain a separating function at the separation area  200 D, the size of the convex portion  204  and the height h from the surface of the rotation table  202  to the lower surface of the convex portion  204  (first ceiling surface  244 ) are to be set based on, for example, experimentation of the applicable range of the number of rotations of the rotation table  202 . Not only nitrogen gas (N2) may be used as the separation gas but also inert gas such as argon (Ar) may be used. Further, other gases such as hydrogen (H 2 ) may be used. As long as the film deposition process is not affected, the kind of gas is not to be limited in particular. 
     As described above, the lower surface of the ceiling plate  211  of the chamber  201  (i.e. ceiling when viewed from the wafer receiving area (concave portion  224 ) of the rotation table  202  includes the first ceiling surface  244  and the second ceiling surface  245  provided in a circumferential direction in a manner where the second ceiling surface  245  is positioned higher than the first ceiling surface  245 .  FIG. 32  is a vertical cross-sectional view of an area having a high ceiling surface  245 .  FIG. 36  is a vertical cross-sectional view of an area having a low ceiling surface  244 . The convex portion  204  has a bent portion  246  that bends in an L-shape at the outer circumferential edge of the convex portion  204  (area at the outer rim of the chamber  201 ). The sector-shaped convex portion  204  is provided towards the ceiling plate  211  and is configured to be detachable from the chamber body  212 . Therefore, a slight gap(s) is provided between the outer peripheral surface of the bent portion and the chamber body  212 . Like the convex portion  204 , the bent portion  246  is also provided for impeding reaction gases from entering and preventing the reaction gases from mixing. The gaps between the bent portion  246  and the rotation table  202  and between the bent portion  246  and the chamber body  212  are set to have substantially the same measurements as the height h of the ceiling surface  244  with respect to the surface of the rotation table  202 . In this embodiment, from the standpoint of the surface of the rotation table  202 , the inner surface of the bent portion  246  serves as an inner circumferential wall of the chamber  201 . 
     As illustrated in  FIG. 36 , the chamber body  212  has an inner circumferential wall formed as a vertical surface in the vicinity of the outer circumferential surface of the bent portion  246  in the separation area  200 D. As illustrated in  FIG. 36 , in an area other than the separation area  200 D, the chamber body  212  has a dented portion (dented towards the outer side) that is notched having a rectangular cross section. The dented portion faces, for example, an area extending from the outer circumferential surface of the rotation table  202  to a bottom surface part  214 . In the dented portion, the areas communicating with the first and second process areas  200 P 1 ,  200 P 2  are referred to as first and second evacuation areas  200 E 1  and  200 E 2 , respectively. Accordingly, as illustrated in  FIGS. 32 and 34 , first and second evacuation ports  261  and  262  are formed at corresponding bottom parts of the first and second evacuation areas  200 E 1  and  200 E 2 . 
     The first and second evacuation ports  261  and  262  are provided for ensuring a separating effect in the separation area  200 D. When viewing the first and second evacuation ports  261 ,  262  from a plan position, the first and second evacuation ports  261 ,  262  are provided on both sides of the separation area  200 D in the rotation direction. Each of the evacuation ports  261 ,  262  is dedicated to evacuate a corresponding reaction gas (BTBAS gas and O3 gas). In this example, the first evacuation port  261  is formed between the first reaction gas nozzle  231  and the separation area  200 D provided adjacent to the first reaction gas nozzle  231  towards the downstream side of the first reaction gas nozzle  231  with respect to the rotation direction. Further, the second evacuation port  262  is formed between the second reaction gas nozzle  232  and another separation area  200 D provided adjacent to the second reaction gas nozzle  232  towards the downstream side of the second reaction gas nozzle  232 . 
     In other words, as illustrated in  FIG. 34 , the first evacuation port  261  of the first evacuation channel  263   a  is provided between the first process area  200 P 1  and the separation area  200 D provided towards the downstream side of the first process area  200 P 1  with respect to the rotation direction (corresponding to area covered by the convex portion  204  at which the separation gas nozzle  242  is provided in  FIG. 34 ). That is, in  FIG. 34 , the first evacuation port  261  is positioned between a straight line L 1  (passing through the center of the rotation table  202  and the first process area  200 P 1 ) and a straight line L 2  (passing through the center of the rotation table  202  and an upstream edge of the separation area  200 D provided towards the downstream side of the first process area  200 P with respect to the rotation direction). The second evacuation port  262  of the second evacuation channel  263   b  is provided between the second process area  200 P 2  and the separation area  200 D provided towards the downstream side of the second process area  200 P 2  with respect to the rotation direction (corresponding to area covered by the convex portion  204  at which the separation gas nozzle  241  is provided in  FIG. 34 ). That is, in  FIG. 34 , the second evacuation port  262  is provided between a straight line L 3  (dash-double-dot line passing through the center of the rotation table  202  and the second process area  200 P 2 ) and a straight line L 4  (dash-double-dot line passing through the center of the rotation table  202  and an upstream edge of the separation area  200 D provided towards the downstream side of the second process area  200 P 2  with respect to the rotation direction). 
     The evacuation ports  261 ,  262  may be located at a part other than the bottom portion of the chamber  201 . For example, the evacuation ports  261 ,  262  may be located in the side wall of the chamber  201 . In addition, when the evacuation ports  261 ,  262  are provided in the side wall of the chamber  201 , the evacuation ports  261 ,  262  may be located higher than the rotation table  202 . In this case, the gases above the rotation table  202  flow towards the outer side of the rotation table  202 . Therefore, it is advantageous in that particles are not blown upward by the gases, compared to evacuating from the ceiling surface facing the rotation table  202 . 
     As illustrated in  FIG. 32 , the first evacuation port  261  is connected to a vacuum pump  264   a  via a first evacuation channel  263   a . For example, the vacuum pump  264   a  is connected to a mechanical booster pump and a dry pump. A first pressure adjusting part  265   a  is interposed between the first evacuation port  261  and the vacuum pump  264   a . Although not illustrated in the drawings, the first pressure adjusting part  265   a  has, for example, a pressure adjustment valve including a butterfly valve, a motor for opening/closing the pressure adjustment valve, and a controller for controlling operation of the motor. For example, the first pressure adjusting part  265   a  is configured as an APC (Auto Pressure Controller) that can perform pressure adjustment based on a detection result from a pressure gage  266   a  connected to the evacuation channel  263   a  provided upstream of the first pressure adjusting part  265   a . In this embodiment, the vacuum pump  264   a  corresponds to a first evacuation part. In the following, the first evacuation channel  263   a , the first pressure adjusting part  265   a , and the vacuum pump  264   a  as a whole may be referred to as a first evacuation system. 
     The pressure gage  266   a  is for measuring the pressure in the first process area  200 P 1  in the chamber (upstream side of the evacuation channel  263   a ). The first pressure adjusting part  265   a  serves to maintain the first process area  200 P 1  in a steady pressure atmosphere by adjusting pressure based on a detection result of the pressure gage  266   a.    
     Likewise, the second evacuation port  262  is connected to, for example, a vacuum pump (second evacuation part)  264   b  via a second evacuation channel  263   b . A second pressure adjusting part  265   b  is interposed between the second evacuation port  262  and the vacuum pump  264   b  for maintaining the second process area  200 P 2  in a steady pressure atmosphere. The second pressure adjusting part  265   b  enables evacuation to be performed independently from the first evacuation channel  263   a . The second pressure adjusting part  265   b  is also configured as an APC (Auto Pressure Controller) that can perform pressure adjustment based on a detection result from a pressure gage  266   b  connected to the evacuation channel  263   b  provided upstream of the second pressure adjusting part  265   b . In the following, the second evacuation channel  263   b , the second pressure adjusting part  265   b , and the vacuum pump  264   b  as a whole may be referred to as a second evacuation system. Further, as illustrated in  FIG. 40 , first and second detoxifiers  267   a ,  267   b  may be provided at each downstream side of the evacuation pumps  264   a ,  264   b  for separately detoxifying ejected matter ejected from each of the vacuum pumps  264   a ,  264   b.    
     As shown in  FIGS. 32 and 37 , a heater unit (heating portion)  207  is provided in a space between the bottom portion  214  of the chamber  201  and the rotation table  202 , so that the wafers W placed on the rotation table  202  are heated through the rotation table  202  at a temperature determined by a process recipe. A cover member  271  is provided beneath the rotation table  202  near the outer circumference of the rotation table  202  in a manner surrounding the entire circumference of the heater unit  207 , so that the atmosphere where the heater unit  207  is located is partitioned from the atmosphere extending from the upper space of the rotation table  202  to the evacuation areas  200 E 1 ,  200 E 2 . The cover member  271  has an upper edge that is bent outward to form a flange shape. Thereby, gas can be prevented from entering the cover member  271  from the outside by reducing the size of the gap between the bent upper edge and a lower surface of the rotation table  202 . 
     At an area located towards the bottom portion  214  and more towards the rotation center than the space where the heater unit  207  is provided, narrow spaces are provided in the vicinity of the center of the lower surface of the rotation table  202  and the core portion  221 . Further, slight gaps, which are provided at a penetration hole through which the rotation shaft  222  passes, are in pressure communication with the inside of the case body  220 . A purge gas supplying pipe  272  is connected to the case body for supplying a purge gas such as N2 gas to the aforementioned narrow spaces. Purge gas supplying pipes  273  are connected to plural areas in the circumferential direction at the bottom portion of the chamber  201  for purging the space where the heater unit  207  is provided. 
     By providing the purge gas supplying pipes  272 ,  273 , N2 gas is purged into the space extending from the inside of the case body  220  to the area where the heater unit  207  is provided. The purge gas is evacuated from the gap between the rotation table  202  and the cover member  271  to the evacuation ports  261 ,  262  via an evacuation area  200 E. Accordingly, because the BTBAS gas or O3 gas is prevented from circling around from one side of the first process area  200 P 1  and the second process area  200 P 2  to the other side of the first process area  200 P 1  and the second process area  200 P 1  via a lower part of the rotation table  202 , the purge gas plays the role of a separation gas. 
     A gas separation supplying pipe  251  is connected to the top center portion of the ceiling plate  211  of the chamber  201 , so that N2 gas is supplied as a separation gas to a space  252  between the ceiling plate  211  and the core portion  221 . The separation gas, which is supplied to the space  252 , is ejected towards the circumferential edges through the thin gap  250  between the protrusion portion  205  and the rotation table  202  and then along the wafer receiving area of the rotation table  202 . Because the separation gas fills the space surrounded by the protrusion portion  205 , reaction gases (BTBAS gas or O3 gas) can be prevented from mixing via the center portion of the rotation table  202  between the first process area  200 P 1  and the second process area  200 P 2 . That is, the film deposition apparatus according to this embodiment is divided into a rotation center portion of the rotation table  200  and the chamber  201  for separating the atmosphere between the first process area  200 P 1  and the second process area  200 P 2 . Further, the film deposition apparatus according to this embodiment is provided with a center area  200 C having an ejection opening formed along a rotation direction at the center portion of the rotation table  202  for ejecting the separation gas on the surface of the rotation table  202 . The ejection opening corresponds to the narrow gap  250  between the protrusion portion  205  and the rotation table  202 . 
     As illustrated in  FIGS. 33, 34, and 39 , a transfer opening  215  is formed in a side wall of the chamber  201  for transferring a wafer W between an outside transfer arm  210  and the rotation table  202 . The transfer opening  215  is provided with a gate valve (not illustrated) by which the transfer opening  215  is opened or closed. When a concave portion (wafer receiving area)  224  of the rotation table  202  is in alignment with the transfer opening  215 , the wafer W is transferred into the chamber  201  and placed in the concave portion  224  as a wafer receiving portion of the rotation table  202  from the transfer arm  210 . In order to lower/raise the wafer W into/from the concave portion  224 , there are provided elevation pins  216  that are raised or lowered through corresponding through holes formed in the concave portion  224  of the rotation table  202  by an elevation mechanism (not illustrated). 
     As illustrated in  FIGS. 32 and 34 , the film deposition apparatus according to an embodiment of the present invention includes a control part  200  including a computer for controlling overall operations of the film deposition apparatus. A program for causing operation of the film deposition apparatus is stored in a memory of the control part  200 . This program includes a group of steps for performing the below-described operation by the film deposition apparatus. This program may be installed to the control part  200  from a storage medium such as a hard disk, a compact disk, a magneto-optical magnetic disk, a memory card, or a flexible disk. 
     As illustrated in  FIG. 32 , the control part  200  is connected to the above-described first and second pressure adjusting parts  265   a  and  265   b . For example, a predetermined pressure value of the controller for each pressure adjusting part  265   a ,  265   b  can be set based on data input from a control terminal (not illustrated) by the user or data set in the memory beforehand. Further, the detection results of the pressure gages  266   a ,  266   b  are also output to the control part  200 . 
     Next, a film deposition method according to an embodiment of the present invention is described. The gate valve (not illustrated) is opened, and a wafer W is transferred into the concave portion  224  of the rotation table  202  from outside via the transfer opening  215  by the transfer arm  202 . The transfer is performed by raising or lowering the elevation pins  216  from the bottom portion of the chamber  201  via the through holes formed at the bottom surface of the concave portion  224  as illustrated in  FIG. 39 . In this example, the transfer is performed by intermittently rotating the rotation table  202  and placing wafers W on five corresponding concave portions  224  of the rotation table  202 . Then, each of the process areas  200 P 1  and  200 P 2  is evacuated to a predetermined pressure by activating the vacuum pumps  264   a ,  264   b  and fully opening the pressure adjustment valves of the first and second pressure adjusting parts  265   a ,  265   b . Further, the wafer W is heated with the heater unit  207  by rotating the rotation table  202  in a clockwise direction. For example, the rotation table  202  is heated to a temperature of approximately 300° C. with the heater unit  207  beforehand, and then the wafer W is heated by being placed on the rotation table  202 . 
     Along with the heating of the wafer W, the pressure inside the chamber  201  is adjusted by supplying N2 gas into the chamber  201  in an amount substantially equal to the amount of reaction gas, separation gas, and purge gas supplied into the chamber  201  after a film deposition process is started. For example, the first reaction gas nozzle  231  supplies N2 gas at a flow rate of 100 sccm, the second gas nozzle  232  supplies N2 gas at a flow rate of 10,000 sccm, separation gas nozzles  241 ,  242  each supplies N2 gas at a flow rate of 20,000 sccm, and the separation gas supplying pipe  251  supplies N2 gas at a flow rate of 5,000 sccm into the chamber  201 . Then, the first and second pressure adjusting parts  265   a ,  265   b  perform opening/closing of the pressure adjustment valves so that the pressure inside the process areas  200 P 1 ,  200 P 2  become the predetermined pressure value, such as 1,067 Pa (8 Torr). It is to be noted that a predetermined amount of N2 gas is also supplied from each purge gas supplying pipe  272 ,  273 . 
     Then, it is determined whether the temperature of the wafer W has reached a predetermined temperature by a temperature sensor (not illustrated) and whether the pressure P in each of the first and second process areas  200 P 1 ,  200 P 2  is a predetermined pressure. Then, the gases supplied from the first and second reaction gas nozzles  231 ,  232  are switched from N2 gas to BTBAS gas and O3 gas, respectively. Thereby, the film deposition process is performed on the wafer W. The switching of the gases of each of the first and second reaction gas nozzle  231 ,  232  is preferably performed slowly in order to prevent the total flow rate of gas supplied to the chamber  201  from steeply changing. 
     Because the wafers W alternatively pass through the first and second process areas  200 P 1 ,  200 P 2  by the rotation of the rotation table  202 , BTBAS gas is adsorbed to the wafer W and then O3 is adsorbed to the wafer W. Thereby, one or more layers of silicon oxide are formed on the wafer W. Accordingly, a silicon oxide film having a predetermined film thickness can be deposited by forming molecular layers of silicon oxide. 
     In this case, N2 gas is also supplied as a separation gas from the gas separation supplying pipe  51 . Thereby, N2 gas is ejected along the surface of the rotation table  202  from the center portion area  200 , that is, the area between the protrusion portion  5  and the center portion of the rotation table  2 . As described above, a wide area is provided by cutting out (notching) the inner circumferential wall of the chamber body  212  provided at a lower side of the second ceiling surface  245 . 
     A gas separation supplying pipe  51  is connected to the top center portion of the ceiling plate  11  of the chamber  1 , so that N2 gas is supplied as a separation gas to a space  52  between the ceiling plate  11  and the core portion  21 . The separation gas, which is supplied to the space  52 , is ejected towards the circumferential edges through the thin gap  50  between the protrusion portion  5  and the rotation table  2  and then along the wafer receiving area of the rotation table  2 . Because the separation gas fills the space surrounded by the protrusion portion  5 , reaction gases (BTBAS gas or O3 gas) can be prevented from mixing via the center portion of the rotation table  2  between the first process area  91  and the second process area  92 . That is, the film deposition apparatus according to this embodiment is divided into a rotation center portion of the rotation table  2  and the chamber  1  for separating the atmosphere between the first process area  91  and the second process area  92 . Further, the film deposition apparatus according to this embodiment is provided with a center area C having an ejection opening formed along a rotation direction at the center portion of the rotation table  2  for ejecting the separation gas on the surface of the rotation table  2 . The ejection opening corresponds to the narrow gap  50  between the protrusion portion  5  and the rotation table  2 . The evacuation ports  261 ,  262  are provided below this wide space. Accordingly, the pressure in the space below the second ceiling surface  245  is lower than the pressure in the narrow space below the first ceiling surface  244  and lower than the pressure in the center portion area  200 C.  FIG. 41  schematically illustrates the state of the flow of gases ejected from respective parts. The O3 gas being ejected to a lower side from the second reaction gas nozzle  232 , contacts the surface of the rotation table  202  (both the surface of the wafer W and the surface of non-receiving area) and flows upstream relative to the rotation direction along the surfaces. Such O3 gas is evacuated from the evacuation port  262  by flowing to the evacuation area  200 E 2  between the circumferential edge of the rotation table  202  and the inner circumferential wall of the chamber  201  as the O3 gas is forced back by the N2 gas flowing from the upstream side. 
     Further, O3 gas being ejected to a lower side from the second reaction gas nozzle  232  flows toward the evacuation port  262  by the flow of N2 gas ejected from the center portion area  200 C and the drawing effect of the evacuation port  262 . However, a portion of the O3 gas flows downstream to a separation area  200 D and into a lower part of the sector-shaped convex portion  204 . Nevertheless, because the height of the ceiling surface  244  of the convex portion  204  and the length of the ceiling surface  244  of the convex portion  204  are set with measurements for preventing gas from flowing to a lower part of the ceiling surface  244  in a case where process parameters during operation (e.g., flow rate of each gas) are used, O3 gas can hardly flow into the lower part of the sector-shaped convex portion  204  or cannot reach the vicinity of the separation gas nozzle  241 . Accordingly, the O3 gas is forced back toward the upstream side relative to the rotation direction (i.e. toward the process area  200 P 2 ) by the N2 gas ejected from the separation gas nozzle  241 . Thus, the O3 gas is evacuated from the evacuation port  262  via the evacuation area  200 E 2  at the gap between the circumferential edge of the rotation table  202  and the inner circumferential wall of the chamber  201  along with the N2 gas ejected from the center portion area  200 C. 
     Further, the BTBAS gas being ejected to a lower part of the first reaction gas nozzle  231  flows towards both the upstream and downstream sides relative to the rotation direction along the surface of the rotation table  202 . Such BTBAS gas can hardly flow into the lower part of the sector-shaped convex portion  204  or is forced back towards the second process area  200 P 1 . Thus, the BTBAS gas is evacuated from the evacuation port  261  via the evacuation area  200 E 1  at the gap between the circumferential edge of the rotation table  202  and the inner circumferential wall of the chamber  201  along with the N2 gas ejected from the center portion area  200 C. In each of the separation areas  200 D, reaction gases (BTBAS gas or O3 gas) flowing in the atmosphere are prevented from entering. However, the gas molecules adsorbed to the wafer W pass the separation area, that is, the lower part of the low ceiling surface  244  of the sector-shaped convex portion  204 , to thereby contribute to film deposition. 
     Further, because the separation gases are ejected from the center portion area  200 C to the circumferential edges of the rotation table  202 , even if the BTBAS gas of the first process area  200 P 1  (O3 gas of the second process area  200 P 2 ) attempt to enter the center portion area  200 C, the separation gases impede or force back the gases (even if the gases enter to some degree). Accordingly, the gases are prevented from flowing through the center portion area  200 C and entering the second process area  200 P 2  (first process area  200 P 1 ). 
     In the separation area  200 D because the circumferential edge parts of the sector-shaped convex portions  204  are bent downward and a gap between such bent portion  246  and an outer edge surface of the rotation table  202  is made narrow, gas can be substantially stopped from passing therethrough. Therefore, BTBAS gas of the first process area  200 P 1  (O3 gas of second process area  200 P 2 ) can be prevented from flowing into the second process area  200 P 2  (first process area  200 P 1 ) via the outer side of the rotation table  202 . Therefore, the atmospheres of the first and second process areas  200 P 1 ,  200 P 2  are substantially completely separated by the two separation areas  200 D. Thus, BTBAS gas can be evacuated from the evacuation port  261  and O3 gas can be evacuated from the evacuation port  262 . As a result, even where both reaction gases (in this example, BTBAS gas and O3 gas) are in the atmosphere, the reaction gases do not mix above the wafer W. 
     In this example, because the lower part of the rotation table  202  is purged with N2 gas, BTBAS gas can be prevented from flowing into the area where O3 gas is supplied. 
     Hence, because the first and second process areas  200 P 1 ,  200 P 2  are connected to dedicated evacuation channels  263   a ,  263   b  via the evacuation areas  200 E 1 ,  200 E 2 , each type of gas flowing into the first process area  200 P 1  and the first evacuation area  200 E 1  is evacuated from the first evacuation channel  263   a  and each type of gas flowing into the second process area  200 P 2  and the second evacuation area  200 E 2  is evacuated from the second evacuation channel  263   b . Therefore, reaction gas supplied to a process area  200 P 1 ,  200 P 2  on one side can be evacuated outside of the chamber  201  without mixing with reaction gas supplied to a process area  200 P 2 ,  200 P 1  on the other side. Accordingly, after the film deposition process is finished, the transfer arm  210  sequentially transfers wafers W out of the vacuum chamber  201  in a manner opposite from the operation of transferring wafers W into the vacuum chamber  201 . 
     An example of process parameters preferable in the film deposition apparatus according to this embodiment is listed below.
     rotational speed of the rotation table  202 : 1-500 rpm (in the case of the wafer W having a diameter of 300 mm)   pressure in the chamber  201 : 1067 Pa (8 Torr)   wafer temperature: 350° C.   flow rate of BTBAS gas: 100 sccm   flow rate of O3 gas: 10000 sccm   flow rate of N2 gas from the separation gas nozzles  241 ,  242 : 20000 sccm   flow rate of N2 gas from the separation gas supplying pipe  251 : 5000 sccm   the number of rotations of the rotation table  202 : 600 rotations (depending on the film thickness required)   

     With the above-described embodiment of the present invention, the following effects can be attained. In this embodiment, there is provided a vacuum chamber  201  having a rotation table  202  includes a first process area  200 P 1  to which a first reaction gas of BTBAS gas is supplied and a second process area  200 P 2  in which a second reaction gas of O3 is supplied. Further, the first and second process areas  200 P 1 ,  200 P 2  are separated from each other in a rotation direction of the rotation table  202 . Further, separation areas  200 D are interposed between the first and second process areas  200 P 1 ,  200 P 2  for supplying separation gas between the first and second process areas  200 P 1 ,  200 P 2  from separation gas supplying parts  241 ,  242 . A thin film deposition process is performed by rotating the rotation table  202  having plural wafers W arranged in a rotation direction and layering plural silicon oxide layers of reaction products with first and second reaction gases of BTBAS gas and O3 gas. Evacuation is performed with an evacuation port  261  of a first evacuation channel  263   a  corresponding to the first process area  200 P 1  and an evacuation port  262  of a second evacuation channel  263   b  corresponding to the second process area  200 P 2 . The evacuation system (evacuation channels  263   a ,  263   b ; pressure adjusting parts  265   a ,  265   b ; evacuation pumps  264   a ,  264   b ) of each of the process areas  200 P 1 ,  200 P 2  is independent from the other. Accordingly, in performing the thin film deposition process, BTBAS gas and O3 gas do not mix in the evacuation systems. Therefore, the possibility of reaction products being generated in the evacuation systems is extremely low. 
     Further, by providing low ceiling planes on both sides of the separation nozzle  241 ,  242  relative to the rotation direction, each reaction gas can be prevented from entering the separation areas  200 D. Further, by ejecting separation gases from the center portion area  200 C (partitioned by the rotation center part of the rotation table  202  and the chamber  201 ) to the circumferential edges of the rotation table  202  and diffusing the separation gas on both sides of the separation area, the separation gas ejected from the rotation center part and the reaction gases can be evacuated via the gaps between the circumferential edges of the rotation table  202  and the inner peripheral wall of the chamber  201 . Thereby, different reaction gases can be prevented from being mixed, satisfactory film deposition can be performed, and generation of particles can be prevented. The present invention may be applied to a case of placing a single wafer W on the rotation table  202 . 
     With the film deposition apparatus according to an embodiment of the present invention, a so-called ALD (or MLD) technique is performed by arranging plural wafers W on the rotation table  202  in a rotation direction of the rotation table  202  and then rotating the rotation table  202  for allowing the wafers W to pass the first and second process areas  200 P 1  and  200 P 2  in order. Therefore, compared to the above-described single-wafer deposition method, the film deposition apparatus requires no time for purging reaction gas and is able to perform film deposition with high throughput. 
     It is to be noted that the evacuation system of the chamber  201  is not limited to two systems. For example, the film deposition apparatus illustrated in  FIG. 42  is provided with a third process area  200 P 3  by adding the convex portion  204  above the rotation table  202 . Accordingly, a third evacuation system (evacuation channel  263   c , third pressure adjusting part  265   c , vacuum pump  264 ) may be connected to the third process area  200 P 3 . In  FIG. 41 , reference numeral  310  indicates a third reaction gas nozzle, reference numeral  410  indicates a separation gas nozzle, and reference numeral  260  indicates an evacuation port. 
     Further, the number of evacuation systems connected to each process area  200 P 1 ,  200 P 2  is not limited to one system. For example, two or more evacuation systems may be connected to each process area  200 P 1 ,  200 P 2 . 
     Further, the method of operating the evacuation system is not limited to adjusting the pressure in the pressure areas  200 P 1 ,  200 P 2  corresponding to each evacuation system as described above. For example, a flow meter may be provided in each evacuation system. Thereby, the opening of the valves provided in the evacuation channels  263   a ,  263   b  can be adjusted so the amount of evacuation from each process area is a predetermined value. Further, the part used for adjusting pressure or the amount of evacuation is not limited to a valve. For example, pressure or amount of evacuation may be adjusted by changing the number of rotations of a mechanical booster pump of the vacuum pumps. 
     As for reaction gases that are used in the present invention other than those of the above-described embodiments of the present invention, there are dichlorosilane (DCS), hexachlorodisilane (HCD), Trimethyl Aluminum (TMA), tris(dimethyl amino) silane (3DMAS), tetrakis-ethyl-methyl-amino-zirconium (TEMAZr), tetrakis-ethyl-methyl-amino-hafnium (TEMHf), bis(tetra methyl heptandionate) strontium (Sr(THD) 2 ), (methyl-pentadionate)(bis-tetra-methyl-heptandionate) titanium (Ti(MPD) (THD)), monoamino-silane, or the like. 
     As illustrated in  FIGS. 43A and 43B , in a case where a wafer W having a diameter of, for example, 300 mm is used as the target substrate, the first ceiling surface  244  that creates the thin space in both sides of the separation gas nozzle  241  ( 242 ) is preferred to have a width L equal to or greater than 50 mm in the rotation direction of the rotation table  202  at a portion where the center WO of the wafer W passes. In order to effectively prevent reaction gases from entering an area below the convex portion  204  from both sides of the convex portion  204 , it is necessary to reduce the distance between the first ceiling surface  244  and the rotation table  202  in a case where the width L is small. Further, in a case where a predetermined length is set to the distance between the first ceiling surface  244  and the rotation table  202 , the speed of the rotation table  202  becomes faster the farther away from the rotation center of the rotation table  202 . Therefore, the width L required for attaining a reaction gas impeding effect becomes greater the farther away from the rotation center. When the length L is less than 50 mm, the distance between the ceiling surface  244  and the rotation table  202  is to be made significantly small. Accordingly, in order to prevent the rotation table  202  or the wafer W from colliding with the ceiling surface  244 , it is necessary to reduce the vibration of the rotation table  202  as much as possible. Further, it becomes easier for reactions gases to enter the lower part of the convex portion  204  from upstream of the convex portion  204  as the number of rotations of the rotation table  202  increases. Thus, when the width L is less than 50 mm, it becomes necessary to reduce the number of rotations of the rotation table  202  which is rather disadvantageous in terms of production throughput. Therefore, it is preferable for the width L to be equal to or greater than 50 mm. Nevertheless, the effects of the present invention may still be attained where the length L is equal to or less than 50 mm. In other words, it is preferable for the width L to be 1/10-1/1 compared to the diameter of the wafer W, and more preferably about ⅙ or greater than the diameter of the wafer W. For the sake of convenience, the concave portion  224  is not illustrated in  FIG. 43A . 
     Examples of the layout of the process areas  200 P 1 ,  200 P 2  and the separation areas  200 D other than the above-described embodiments of the present invention are described below.  FIG. 44  illustrates an example where the second reaction nozzle  232  is positioned upstream from the transfer opening  215  with respect to the rotation direction of the rotation table  202 . The same effect as the above-described embodiments of the present invention can be attained even with this layout. 
     In this embodiment, as illustrated in  FIG. 45 , in addition to providing low ceiling surfaces (first ceiling surfaces)  244  on both sides of the separation gas nozzle  241  ( 242 ) for forming narrow gaps, low ceiling surfaces are also provided on both sides of the reaction gas nozzle  231  ( 232 ), so that the ceiling surfaces are formed to be continuous. In other words, even in a case where the convex portion  204  is provided to the entire area facing the rotation table  202 , the same effect can be attained except at the areas other than the areas where the separation gas nozzle  241  ( 242 ) and the reaction gas nozzle  231  ( 232 ) are provided. From a different standpoint, this configuration has the first ceiling surfaces  244  on both sides of the separation gas nozzle  241  ( 242 ) extending to the reaction gas nozzle  231  ( 232 ). In this case, although the separation gas diffusing to both sides of the separation nozzle  241  ( 242 ) and separation gas diffusing to both sides of the reaction gas nozzle  231  ( 232 ) merge at a lower part of the convex portion  204  (narrow gap), the gases are evacuated from the evacuation port  261  ( 262 ) positioned between the separation gas nozzle  242  ( 241 ) and the reaction gas nozzle  231  ( 232 ). 
     In the above embodiments, the rotation shaft  222  for rotating the rotation table  202  is located in the center portion of the chamber  201 . In the above-described embodiment of the present invention, the space between the core portion of the rotation table  202  and the upper surface of the chamber  201  is purged with the separation gas. However, the chamber  201  may be configured as illustrated in  FIG. 46 . In the film deposition apparatus of  FIG. 46 , the bottom portion  214  of the center area of the chamber  201  includes a housing space  280  of a driving portion and a concave portion  280   a  formed on the upper surface of the center portion of the chamber  201 . A pillar  281  is placed between the bottom surface of the housing space  280  and the upper surface of the concave part  280   a  at the center portion of the chamber  201  for preventing the first reaction gas (BTBAS) ejected from the first reaction gas nozzle  231  and the second reaction gas (O3) ejected from the second reaction gas nozzle  232  from being mixed through the center portion of the chamber  201 . 
     In addition, a rotation sleeve  282  is provided so that the rotation sleeve  282  coaxially surrounds the pillar  281 . A ring-shape rotation table  202  is provided along the rotation sleeve  282 . Further, a driving gear portion  284 , which is driven by a motor  283 , is provided in the housing space  280 . The rotation sleeve  282  is rotated by the driving gear portion  284  via a gear portion  285  formed on the outer surface of the rotation sleeve  282 . Reference numerals  286 ,  287 , and  288  indicate bearings. A purge gas supplying pipe  274  is connected to a bottom part of the housing space  280 , so that a purge gas is supplied into the housing space  280 . Another purge gas supplying pipe  275  is connected to an upper part of the housing space  280 , so that a purge gas is supplied between a side surface of the concave portion  280   a  and an upper edge part of the rotation sleeve  282 . Although opening parts for supplying the purge gas to the space between the side surface of the concave portion  280   a  and the upper edge part of the rotation sleeve  282  are illustrated in a manner provided on two areas (one on the left and one on the right) in  FIG. 46 , the number of the opening parts (purge gas supplying port) may be determined so that the purge gas from the BTBAS gas and the O3 gas in the vicinity of the rotation sleeve  282  can be prevented from being mixed. 
     In the embodiment illustrated in  FIG. 46 , a space between the side wall of the concave portion  280   a  and the upper end portion of the rotation sleeve  282  corresponds to the ejection hole for ejecting the separation gas. Thus, in this embodiment, the ejection hole, the rotation sleeve  282 , and the pillar  281  constitute the center portion area provided at a center part of the chamber  201 . 
     The film deposition apparatus according to embodiments of the present invention may be integrated into a wafer process apparatus, an example of which is schematically illustrated in  FIG. 47 . The wafer process apparatus includes an atmospheric transfer chamber  292  in which a transfer arm  293  is provided, load lock chambers (preparation chambers)  294 ,  295  whose atmosphere is changeable between vacuum and atmospheric pressure, a vacuum transfer chamber  296  in which two transfer arms  297  are provided, and film deposition apparatuses  298 ,  299  according to embodiments of the present invention. In addition, the wafer process apparatus includes cassette stages (not shown) on which a wafer cassette  291  such as a Front Opening Unified Pod (FOUP) is placed. The wafer cassette  291  is brought onto one of the cassette stages, and connected to a transfer in/out port provided between the cassette stage and the atmospheric transfer chamber  292 . Then, a lid of the wafer cassette (FOUP)  291  is opened by an opening/closing mechanism (not shown) and the wafer is taken out from the wafer cassette  291  by the transfer arm  293 . Next, the wafer is transferred to the load lock chamber  294  ( 295 ). After the load lock chamber  294  ( 295 ) is evacuated, the wafer in the load lock chamber  294  ( 295 ) is transferred further to one of the film deposition apparatuses  298 ,  299  through the vacuum transfer chamber  296  by the transfer arm  297   a  ( 297   b ). In the film deposition apparatus  298  ( 299 ), a film is deposited on the wafer in such a manner as described above. Because the wafer process apparatus has two film deposition apparatuses  298 ,  299  that can house five wafers at a time, the ALD (or MLD) mode deposition can be performed at high throughput. 
     Further, the present invention is not limited to these embodiments, but variations and modifications may be made without departing from the scope of the present invention.
There is disclosed a film deposition apparatus and a film deposition method for depositing a film on a substrate by carrying out cycles of supplying in turn at least two source gases to the substrate in order to form a layer of a reaction product, and a computer readable storage medium storing a computer program for causing the film deposition apparatus to carry out the film deposition method.