A method for manufacturing a semiconductor device, includes: forming a first metal layer on a semiconductor substrate, the semiconductor substrate including a diffusion layer; forming an insulating layer having an opening on the first metal layer; forming a second metal layer on the first metal layer in the opening of the insulating layer; removing the insulating layer; covering an exposed surface of the second metal layer with a third metal layer, the third metal layer including a metal having an ionization tendency lower than that of the second metal layer; and forming an electrode interconnect including the first metal layer, the second metal layer, and the third metal layer by removing the first metal layer using the third metal layer as a mask.