To perform fine interconnections by providing the interconnections of a multilayer structure formed with dry etching resistant film on a low resistant metal layer.

After a through hole is provided on the predetermined part of a first interlayer insulating film 15, interconnection material is formed by a sputtering unit, and patterned by dry etching to form the first interconnection 16. The interconnection 16 becomes, for example, a multilayer structure that an Mo layer 16a, an Au layer 16b and a carbon layer 16c are sequentially stuck. The degree of sticking of the layers 16c and 16b as a mask layer is higher as compared with that of the conventional Au layer to an SiO2 film since it is formed continuously by the same sputtering unit. Accordingly, since the layer 16c sufficiently functions as the mask layer at the time of dry etching, accurate dry etching is conducted. Thus, the microminiaturization of etching can be performed.