Patent ID: 7202171

Claim:
A process for forming an opening in an insulative layer formed over a substrate in a semiconductor device, said process comprising: forming a pair of adjacent gate stacks over said substrate; forming sidewall spacers on sidewalls of said adjacent gate stacks; forming an insulative layer over said substrate; forming a patterned photoresist mask layer over said insulative layer; and, etching an opening in said insulative layer defined at least in part by said sidewall spacers through an aperture in said patterned photoresist mask layer, wherein said opening is etched through to said substrate using a combination consisting essentially of ammonia and at least one fluorocarbon, wherein said at least one fluorocarbon is selected from the group consisting of C 4 F 8 , C 4 F 6 , C 5 F 8 , CF 4 , C 2 F 6 , CHF 3 , CH 2 F 2 and C 3 F 8 , and wherein the flow rate ratio of said at least one fluorocarbon to said ammonia is from about 2:1 to about 40:1, and wherein the step of etching an opening in said insulative layer forms a protective layer on said sidewall spacers that is from about 5 to about 50 Å thick.