PURPOSE: To obtain an aluminum laminated wiring structure where a wiring long in service life can be formed by a method wherein a dissimilar metal material layer is formed, and then the surface of the dissimilar metal layer is smoothed.

CONSTITUTION: An interlayer isolation film 3 is formed on a lower wiring or a diffusion layer 11 of a substrate 1 of Si or the like, a wafer provided with an opening 4 is set in a sputtering device, and a dissimilar metal material layer 2 of barrier metal formed of Ti/TiON/Ti is formed on the wafer concerned. Then, the wafer concerned is taken out from the sputtering device, transferred to a microwave etching device, and etched with Cl2/O2 gas as operating gas, whereby oxychloride is deposited on the recesses of the wafer, and consequently projections on the surface of the wafer are selectively etched to make the surface of the wafer smooth. In succession, Al-Si alloy is sputtered to form an Al material layer is formed. By this setup, the surface of barrier metal is smoothed, so that an Al, material layer through which a wiring high in reliability and long in service life can be formed is obtained.