PURPOSE: To obtain bumps cheaply without the necessity of expensive facilities, by forming bumps by electrolytic plating using a conductive resin layer formed on a wafer, as an electrode.

CONSTITUTION: A conductive resin layer 14 is formed on the surface of a semiconductor wafer 11. Concerning to its formation method; it is formed by adhering a filmlike substance, or by printing or spin-coating liquid conductive resin and hardening it. Next, a photosensitive resin layer 15 is formed on the conductive resin layer 14. Next openings are formed in the photosensitive resin layer 15 on the aluminum electrodes 12 of a semiconductor wafer 11 by photolithography technique, and openings 16 are formed in the conductive resin layer 14 using the photosensitive resin layer 15 as a mask. Next, electrolytic plating of Au, Cu, etc., is performed to form bumps 17 in the openings 16, using the conductive resin layer 14 as an electrode. Next, the photosensitive resin layer 15 and the conductive resin layer 14 are removed, and the bumps 17 are left on the aluminum electrodes 12 of the semiconductor wafer 11. Consequently, it becomes possible to obtain bumps cheaply.