Plasma etching reactor with reduced plasma potential

Abstract

An improved plasma reactor for uniformly etching a large number of semiconductor wafers at a reduced plasma potential includes, in one embodiment, a grounded plate mounted intermediate the cathode and the top plate of a reactor chamber, the top plate and the chamber walls forming the reactor anode. The grounded plate is spaced apart from the chamber top plate a distance sufficient to allow a plasma to be established between the grounded plate and the top plate, and the distance between the grounded plate and the cathode is large enough not to disturb the field in the proximity of the wafers being etched. The plate can be apertured to facilitate etchant gas flow. According to another embodiment of the invention at least two grounded plates are employed, spaced apart from each other and from the upper surface of the reactor plasma chamber.

Dependencies are inferred from the claim text.