A manufacturing method for a semiconductor device, including the steps of: forming a passivation film that covers a surface of a semiconductor substrate on which electrodes have been formed, in which an opening is formed so as to expose a predetermined electrode from among the electrodes; forming a diffusion prevention plug of a first metal in the vicinity of the opening in the passivation film; supplying a second metal material to the surface of the semiconductor substrate on which the diffusion prevention plug has been formed, so as to form a seed layer of the second metal; forming a resist film that covers the seed layer and in which an opening is formed so as to expose a predetermined region of the seed layer on the diffusion prevention plug; supplying a third metal material into the opening in the resist film so as to form a protrusion electrode of the third metal; removing the resist film after the step of forming a protrusion electrode; and removing the seed layer after the step of forming a protrusion electrode.