WAFER AREA PRESSURE CONTROL FOR PLASMA CONFINEMENT
A plasma processing chamber is provided which provides improved wafer area pressure control. The plasma processing chamber is a vacuum chamber with a device connected for generating and sustaining a plasma. Part of this device would be an etchant gas source and an exhaust port. A confinement ring defines an area above a wafer. The wafer area pressure is dependent on the pressure drop across the confinement ring. The confinement ring is part of a wafer area pressure control device that provides wafer area pressure control range greater than 100 %. Such a wafer area pressure control device may be three adjustable confinement rings and a confinement block on a holder that may be used to provide the desired wafer area pressure control.