To prevent the destruction of the gate electrode of a semiconductor device and reduce the wiring resistance by processing the wiring of the gate electrode by a dry etching, wherein the plasma luminescent bright line of the product of the etching is used for sensing the end point of the etching, and by confirming the change of the emission intensity in the boundary between its polycrystalline silicon film and a high-melting-point metal silicide film.

After completion of the patterning of a gate electrode 11 by an anisotropy etching, when the intensity of the plasma emission bright line of a product in the case of the etching, wherein the main component is silicon tends to reduce in the vicinity of the interface between a high-melting-point metal silicide film 10 and a polycrystalline silicon film 9, it is judged that peeling of the high-melting-point metal silicide film 10 is possible in a semiconductor substrate 1, and the formation of a mask oxide film in a subsequent process is interrupted. Thereby, the high-melting-point metal silicide film 10, which is an upper layer film for forming the wiring of the gate electrode 11 is prevented in a heat treatment equipment, and the destruction of the gate electrode 11 with a polyside structure can be prevented to sufficiently reduce the resistance of the wiring.