Method for production of semiconductor device

A method for the production of a semiconductor device having an electrode line formed in a semiconducting substrate is disclosed which comprises preparing a semiconducting substrate having trenches and/or contact holes formed preparatorily in a region destined to form the electrode line, forming a conductive film formed mainly of at least one member selected from among Cu, Ag, and Au on the surface of the semiconducting substrate, heat-treating the superposed Cu film while supplying at least an oxidizing gas thereto thereby flowing the Cu film to fill the trenches and/or contact holes, and removing by polishing the part of the conductive film which falls outside the region of the electrode line and completing the electrode lines consequently. During the heat treatment, a reducing gas is supplied in addition to the oxidizing gas to induce a local oxidation-reduction reaction and fluidify and/or flow the conductive film and consequently accomplish the embodiment of the conductive film in the trenches.