Patent ID: 7176139

Claim:
An etching method in a semiconductor processing comprising: forming a polysilicon layer, a tungsten silicide layer and an anti-reflective layer on a wafer; generating plasma while setting a bias power applied to the wafer to zero and applying a source power for about 5 to about 90 seconds using a first processing gas of CF 4 /Ar; executing an etching process onto the anti-reflective layer by setting the bias power to a first predetermined value; generating plasma while setting the bias power to zero and applying the source power for about 5 to about 90 seconds using a second processing gas of Cl 2 /SF 6 ; executing an etching process onto the tungsten silicide layer and the polysilicon layer by setting the bias power to a second predetermined value; generating plasma while setting the bias power to zero and applying the source power for about 5 to about 90 seconds using a third processing gas of HBr/O 2 ; and executing an etching process onto the polysilicon layer by setting the bias power to a third predetermined value.