Abstract: A tungsten silicide (WSi) film is formed of tungsten hexafluoride (WF6) and dichlorosilane (SiCl2) as main raw material on a polysilicon film by the CVD method. At the final stage of this film forming process, supply of tungsten hexafluoride is terminated to relax internal stresses. As a result, on the tungsten silicide film, an Si-rich tungsten silicide film containing chlorine ions in a high concentration is formed. Then, before coating a chemical amplification photoresist, these films along with a silicon substrate are soaked in an etching liquid containing hydrogen peroxide to remove the Si-rich tungsten silicide film so that generation of ammonia chloride, which suppresses an alkali developing action, can be controlled. Thus the tungsten silicide film can be patterned by photolithography without pattern defects.