To provide a semiconductor device having improved reliability by improving a coupling property between a semiconductor chip and a bonding wire. A redistribution layer is comprised of a Cu film, an Ni film, and a Pd film which have been formed successively from the side of a semiconductor substrate. The Pd film on the uppermost surface is used as an electrode pad and a bonding wire made of Cu is coupled to the upper surface of the Pd film. The thickness of the Pd film is made smaller than that of the Ni film and the thickness of the Ni film is made smaller than that of the Cu film. The Cu film, the Ni film, and the Pd film have the same pattern shape in a plan view.