A metallic wiring film, which is not exfoliated even when exposed to plasma of hydrogen, is provided. A metallic wiring film is constituted by an adhesion layer in which Al is added to copper and a metallic low-resistance layer which is disposed on the adhesion layer and made of pure copper. When a copper alloy including Al and oxygen are included in the adhesion layer and a source electrode and a drain electrode are formed from it, copper does not precipitate at an interface between the adhesion layer and the silicon layer even when being exposed to the hydrogen plasma, which prevents the occurrence of exfoliation between the adhesion layer and the silicon layer. If the amount of Al increases, since widths of the adhesion layer and the metallic low-resistance layer largely differ after etching, the maximum addition amount for permitting the etching to be performed is the upper limit.