Patent ID: 8394686

Claim:
A method comprising: dry etching an amorphous silicon film that is formed on a silicon nitride film, by parallel-plate type dry etching using an etching gas including at least COF 2 ; wherein the dry etching achieves an etching rate of the silicon nitride film that is lower than an etching rate of the amorphous silicon film; wherein the amorphous silicon film comprises an intrinsic amorphous silicon film and an n-type amorphous silicon film formed on the intrinsic amorphous silicon film; wherein the method is performed in a process of manufacturing a channel-protection-film type thin film transistor of a reverse-staggered type, in which a silicon thin film is formed on a gate insulating film made of the silicon nitride film, and ohmic contact layers are formed on both sides of an upper surface of the silicon thin film; wherein the n-type amorphous silicon film and the intrinsic amorphous silicon film are sequentially dry etched to form the ohmic contact layers and the silicon thin film; wherein the etching gas is a mixed gas including COF 2 gas and chlorine gas; and wherein the amorphous silicon film is etched while using the silicon nitride film as a stopper.