A reliable semiconductor device is provided with a layered interconnect structure that may develop no problem of voids and interconnect breakdowns, in which the layered interconnect structure includes a conductor film and a neighboring film so layered on a semiconductor substrate that the neighboring film is in contact with the conductor film. In the device, the materials for the conductor film and the neighboring film are so selected that the difference between the short side, a_p, of the rectangular unit cells that constitute the plane with minimum free energy of the conductor film and the short side, a_n, of the rectangular unit cells that constitute the plane with minimum free energy of the neighboring film, {|a_p-a_n|/a_p}100=A (%) and the difference between the long side, b_p, of the rectangular unit cells that constitute the plane with minimum free energy of the conductor film and the long side, b_n, of the rectangular unit cells that constitute the plane with minimum free energy of the neighboring film, {|b_p-b_n|/b_p}100=B (%) satisfy an inequality of {A+B(a_p/b_p)}13. In this way, the diffusion of the conductor film is retarded.