Patent ID: 6030486
Filing Date: 2000-02-29
Classification: H01J

Abstract:
An RF plasma reactor for processing a semiconductor wafer, comprising:a reactor chamber bounded by a chamber wall, and a gas inlet for furnishing a plasma precursor gas into said chamber;an RF power source and an RF coupler proximal said chamber and connected to said RF power source for coupling RF plasma source power into said chamber;a wafer pedestal in said chamber for supporting a semiconductor wafer to be processed in said reactor;a pumping annulus adjacent a peripheral portion of said chamber and a vacuum pump coupled to said pumping annulus, said pumping annulus being coupled to said chamber through a circumferential gap between said pedestal and said chamber wall; anda closed magnetic circuit comprising:a first pair of magnetic poles of opposite magnetic polarity disposed on a first side of said gap;a second pair of magnetic poles of opposite magnetic polarity disposed on a second side of said gap, said second side opposite said first, side said first and second pairs of magnetic poles having sufficient magnetic strength to prevent plasma ions in said chamber from traveling through said gap into said pumping annulus.