PURPOSE: To reduce a bump pitch remarkably and to accomplish the high density ratio of the bump by a method wherein, after the base layer has been formed in pad shape using a metal layer of excellent adhesiveness and a metal layer of excellent suitability of plating in advance, a gold bump plating work is conducted.

CONSTITUTION: A metal layer 4, having excellent adhesion with the base layer and a metal layer 5, having excellent suitability for plating, are formed on the semiconductor wafer 1 which is coated with a protective film 3 excluding an Al electrode part 2, and a pad-like masking layer 6 is formed on the Al electrode part 2 using a photoresist and the like. The unnecessary parts of the metal layers 4 and 5 are removed by etching, then the masking layer 6 is removed, and a metal layer 7 having excellent suitability for plating is formed. Then, a masking layer 8, having resistance against a gold-plating solution is formed thereon excluding the Al electrode part 2, which is the gold bump formed part. A gold bump 9 is plated on the aperture part of the masking layer 8, and lastly, the masking layer 8 and the metal layer 7 are removed, and the formation of a gold bump is completed.