A tungsten silicide layer (104) is etched by plasma etching using Cl2+O2 gas as etching gas. When etching of the tungsten silicide layer (104) is ended substantially, etching gas is switched to Cl2+O2+NF3 and over etching is performed by plasma etching. Etching process is ended under a state where a polysilicon layer (103) formed beneath the tungsten silicide layer (104) is slightly etched uniformly. Residual quantity of the polysilicon layer (103) can be made uniform as compared with prior art and a high quality semiconductor device can be fabricated stably.