METHOD FOR FORMING METAL GATE OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming a metal gate of a semiconductor device is provided to restrain the difference of stress between a substrate and a spacer by using selective oxidation processing. CONSTITUTION: A gate oxide layer(200), a polysilicon layer(300b), a tungsten film(400a) and a nitride hard mask(500a) are sequentially formed on a semiconductor substrate(100). The nitride hard mask and the tungsten film are selectively removed. The polysilicon layer(300b) is partially removed without exposing the gate oxide layer, thereby forming a gate pattern(600). A buffer layer(350) is formed by selective oxidation processing of the polysilicon layer(300b). Then, a gate spacer is formed at both sidewalls of the gate pattern.