PURPOSE: To suppress the peeling from a semiconductor substrate of the contact wiring, which is made by stacking a metal in the opening later, with a step by etching the end face of the virtual silicate glass film inside the opening with etchant so as to make this step to the silicon nitride film of the middle layer.

CONSTITUTION: A silicate glass (NSG) film 2, an Si3N4 film 3, and a boron phosphorus silicate glass(BPSG) film 4 are formed on a silicon substrate 1, where elements (channel, source, drain, etc.) are made. The area aiming at formation of the contact wiring of an interlayer insulating film is etched to form an opening. In this opening, the end faces of an NSG film 2, an Si3N4 film 3, and a BPSG film 4 are exposed. The substrate is processed in buffered fluoric acid aqueous solution, and the end face of the NSG film 2 is processed so that it may be the retreated end face from the Si3N4 end face by dissolving itself. Selective tungsten growth is performed inside the opening to form contact wiring 5.