FIG 17 is a schematic cross sectional diagram of {HEAD ~ a vacuum pump unit} attached to {TAIL ~ the LPCVD apparatus} of a ninth embodiment of the present embodiment, and FIG 18 is a graph illustrating output characteristics of a vacuum pump unit 
attached to
FIG 17 is a schematic cross sectional diagram of { HEAD ~ a vacuum pump unit } attached to { TAIL ~ the LPCVD apparatus } of a ninth embodiment of the present embodiment , and FIG 18 is a graph illustrating output characteristics of a vacuum pump unit
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH