Abstract: A method for producing a semiconductor device includes solder-connecting a semiconductor chip, onto an insulating substrate including a ceramic board and having conductor layers on two surfaces thereof, with a lead-free solder; warping a radiating base such that a surface of the radiating base on a side opposite to the insulating substrate is convex; and solder-connecting the insulating substrate onto the warped radiating base with the lead-free solder so as to provide a substantially flat solder-connected radiating base.

Abstract: A method for producing a semiconductor device includes solder-connecting a semiconductor chip, onto an insulating substrate including a ceramic board and having conductor layers on two surfaces thereof, with a lead-free solder; warping a radiating base such that a surface of the radiating base on a side opposite to the insulating substrate is convex; and solder-connecting the insulating substrate onto the warped radiating base with the lead-free solder so as to provide a substantially flat solder-connected radiating base.

Abstract: A high-reliability power semiconductor device uses a lead-free solder layer to connect a semiconductor chip such as an IGBT to an insulating substrate having a ceramic board and conductor layers, and a lead-free solder layer to connect the insulating substrate to a radiating base. Before the insulating substrate and the radiating base are solder-connected, the radiating base is warped such that the surface of the radiating base on the side opposite to the insulating substrate is convex. The insulating substrate is solder-connected onto the warped radiating base with the lead-free solder so as to provide a substantially flat solder-connected radiating base. When the radiating base is attached to a cooling fin, the thermal resistances are lower, and heat from the semiconductor chip is effectively dissipated so as to prevent abnormal temperature rise.