Patent ID: 7682985

Claim:
A method of etching a polysilicon layer over a substrate, wherein the polysilicon layer has at least one doped region and at least one undoped region, comprising: placing the substrate in a processing chamber; providing an etchant gas into the processing chamber, wherein the etchant gas comprises N 2 , SF 6 , and at least one of CHF 3 and CH 2 F 2 ; and transforming the etching gas to a plasma to simultaneously etch the at least one doped region and at least one undoped region of the polysilicon layer; and directly thereafter providing a polysilicon main etch, comprising: providing an etchant gas with at least one of Cl 2 , HBr, CF 4 , and O 2 ; and transforming the etching gas to a plasma to etch the polysilicon layer.