PURPOSE: To prevent generation of strain and fine crack to a neighbouring insulating layer, and improve the reliability of equipment, by making up a metal fine wire of copper, and making the thickness of a pad larger than that of a wiring layer.

CONSTITUTION: A bed part 1 and an external lead 2 are arranged in a lead frame, and a semiconductor substrate 3 is mounted on the bed part 1. A wiring formed on the substrate 3 is about 1μm thick which is deposited by one depositing process, and its patterning also is obtained by one PEP process. The thickness of the pad 6, t1 and that of the wiring 4, t2, have a relation of t1>t2. In the process of wire bonding to the external lead 2, the pad 6 is subjected to a thermal contact bonding to a metal thin wire 7 applying a load in an inactive atmosphere. The metal thin wire is made of Cu as a main component, and an oxide film is not coated on the surface.