In a method of manufacturing a semiconductor device which method is made up of a process of forming a wiring groove using a hard mask, a metal hard mask 107 is used to form a wiring groove 111, allowing the shape of the wiring groove 111 to be stabilized. Furthermore, a part or all of the metal hard mask 107 is removed before the formation of TaN and Cu layers in the wiring groove 111. This enables a reduction in possible damage, which may increase the dielectric constant of the surface of low-dielectric-constant film, and thus in possible inter-wire leakage current. As a result, a reliable semiconductor device can be provided.