Patent ID: 7256125

Claim:
A manufacturing method of a semiconductor device, comprising the steps of: (a) providing a semiconductor substrate; (b) forming an insulating film over the semiconductor substrate; (c) forming a polycrystalline silicon film over the insulating film; (d) forming a W x Si y film over the polycrystalline silicon film; (e) patterning the W x Si y film and the polycrystalline silicon film; and (f) after the step (e), performing heat treatment, wherein the step (c) comprises sub-steps of: (c1) forming a second region of the polycrystalline silicon film over the insulating film; and (c2) forming a first region of the polycrystalline silicon film over the second region of the polycrystalline silicon film, with an impurity concentration of the first region of the polycrystalline silicon film being smaller than that of the second region of the polycrystalline silicon film, wherein in the step (d), the W x Si y film is formed so as to satisfy y/x≧2, and wherein the W x Si y film formed in the step (d) has a resistivity of 1000 μΩcm or greater and has a resistivity of 400 μΩcm or less after the heat treatment in the step (f).