Fabrication method of wiring substrate for mounting semiconductor element and semiconductor device

A method of fabricating a wiring substrate for mounting a semiconductor element, the method comprising the steps of:

• providing a metal base, the metal base having a surface;
• forming a first resist film on the surface of the metal base, the first resist film having a negative pattern with respect to a wiring film to be subsequently formed;
• forming a second resist film on the first resist film and on the surface of the substrate, the second resist film having a negative pattern with respect to a bump to be subsequently formed at a location between a predetermined part of the wiring film and the surface of the metal base;
• forming the bump by electrolytic plating on the surface of the metal base using the second resist film as a mask;
• removing the second film by using a removal means capable of removing the second resist film and incapable of removing the first resist film;
• and
• after forming the second resist film, forming the wiring film by electrolytic plating on the surface of the metal base using the first resist film as a mask.