Patent ID: 6869885

Claim:
A method for selectively etching a substrate having a tungsten silicide layer with a resist material on portions of the tungsten silicide layer, the method comprising: introducing process gas comprising SF 6 , HBr, He, and a chlorine containing gas onto the substrate, the volumetric flow ratio of SF 6 :HB ranging from about 1:0.95 to about 1:1.85, and the volumetric flow ratio of the SF 6 :He ranging from about 1:3.95 to about 1:7.69; the volumetric flow ratio of SF 6 :chlorine containing gas ranging from about 1:0.68 to about 1:1.46; and generating a plasma to form an etch gas from the process gas, wherein the etch gas selectively etches tungsten silicide layer on the substrate.