Solder bump joining structure with low resistance joining member

摘要

A semiconductor device is provided with a wiring substrate including a connection pad, a joining member joined with the connection pad, and a semiconductor chip including a connection terminal electrically connected to the connection pad via the joining member. The joining member consists of a first intermetallic compound layer formed at a boundary between the connection pad and the joining member, a second intermetallic compound layer formed at a boundary between the connection terminal and the joining member, a third intermetallic compound layer composed of an intermetallic compound of Cu₆Sn₅ or (Cu,Ni)₆Sn₅ and formed between the first intermetallic compound layer and the second intermetallic compound layer, and discrete metal grains, each being composed of a simple substance of Bi, in the third intermetallic compound layer. Surfaces of each of the metal grains are completely covered by the third intermetallic compound layer so that the metal grains do not form a layer.