A reliable semiconductor device is provided which comprises lower and upper IGBTs 1 and 2 preferably bonded to each other by solder, and a wire strongly connected to lower IGBT 1. The semiconductor device comprises a lower IGBT 1, a lower electrode layer 5 secured on lower IGBT 1, an upper electrode layer 6 secured on lower electrode layer 5, an upper IGBT 2 secured on upper electrode layer 6, and a solder layer 7 which connects upper electrode layer 6 and upper IGBT 2. Lower and upper electrode layers 5 and 6 are formed of different materials from each other, and upper electrode layer 6 has a notch 36 to partly define on an upper surface 5a of lower electrode layer 5 a bonding region 15 exposed to the outside through notch 36 so that one end of a wire 8 is connected to bonding region 15. Upper electrode layer 6 can be formed of one material superior in soldering, and also, lower electrode layer 5 can be formed of another material having a high adhesive strength to wire 8.