A method for production of semiconductor devices which includes the steps of forming, on an interlayer insulating film formed on a substrate, a copper-containing conductive layer in such a way that its surface is exposed, performing heat treatment with a reducing gas composed mainly of hydrogen on the surface of the conductive layer, performing plasma treatment with a reducing gas on the surface of the conductive layer, thereby permitting the surface of the conductive layer to be reduced and the hydrogen adsorbed by the heat treatment to be released, and forming an oxidation resistance film that covers the surface of the conductive layer such that the surface of the conductive layer is not exposed to an oxygen-containing atmospheric gas after the plasma treatment.