Patent ID: 7960268

Claim:
A method of manufacturing a semiconductor device, comprising the steps of: preparing a semiconductor substrate having a isolation layer to define an active region; forming a gate insulation layer on the semiconductor substrate; sequentially forming a polysilicon layer, a first metal silicide layer, a metal nitride layer and a metal layer on the gate insulation layer including the isolation layer; etching the metal layer and the metal nitride layer so that the metal layer and the metal nitride layer have a narrower width than that of a desired gate; forming a second metal silicide layer on the first metal silicide layer including the etched metal nitride layer and the metal layer; forming a hard mask on the second metal silicide layer so that the hard mask has a desired gate width; and etching the second metal silicide layer, the first metal silicide layer, the polysilicon layer and the gate insulation layer by using the hard mask as an etching barrier, so as to form a metal gate with a structure in which the metal nitride and the metal layer are enclosed with the first and second metal silicide layers.