Patent ID: 6030489
Filing Date: 2000-02-29
Classification: H01J,H01L

Abstract:
A plasma assisted chemical etching apparatus for doing etching operations on the surface of semiconductor wafers, comprising:a) a vacuum chamber;b) a means for generating a plasma field between a moveable upper consumable electrode and a stationary lower non-consumable electrode within said vacuum chamber;c) an interlock means for passing a wafer into said vacuum chamber;d) a wafer support means contiguous to an upper surface of the lower non-consumable electrode;e) a first port means connected to a throttle valve and to an external pumping source;f) a second port for communicating with trifurcated ports disposed circularly and spaced equally on the underside of an annular upper electrode clamp;g) a third port means for admission of a process gas from an external source;h) a first manometer means connected externally to the first port to sense the vacuum chamber pressure adjacent said lower non-consumable electrode;i) a first pressure controller implementing a pressure feedback communicated by said first manometer means;j) a throttle valve which is actuated by said first pressure controller to equalize the vacuum chamber pressure to a preset process parameter; and,k) a second pressure manometer mounted to said second port to communicate pressure from said trifurcated ports to a gap controller that repeatedly computes new gap counts based on pressure feedback from said second manometer.