After an interlayer insulation film (1) and a CMP stopper film are formed, wiring trenches are formed. Next, after a barrier metal film (4) and a Cu film (5) are buried in the wiring trenches, the Cu film (5) and the barrier metal film (4) are planarized by CMP or the like until the CMP stopper film is exposed, whereby lower wirings (17) are formed. Next, the CMP stopper film is removed by dry etching, so that surfaces of the lower wirings (17) relatively protrude from their surrounding area. Subsequently, an etching stopper film (6) is formed on the entire surface. Thereafter, via plugs (18) are formed, and upper wirings (19) are further formed in the same manner as the lower wirings (17).
