In one embodiment, a semiconductor device includes a first insulator. The device further includes a metal layer that includes a first metal layer provided on a surface of the first insulator, and a second metal layer provided on a surface of the first metal layer and containing a first metallic element and oxygen or containing aluminum and nitrogen, or includes a third metal layer provided on the surface of the first insulator and containing a second metallic element, aluminum and nitrogen. The device further includes an interconnect material layer provided on a surface of the metal layer.