Method of manufacturing semiconductor device

A method of manufacturing a semiconductor device, comprising:

• preparing a heat-dissipating base that has a front surface and a rear surface;
• performing one of
• a first initial warping including
• performing shot peening on the rear surface of the heat-dissipating base to form a hardened layer, and
• subsequently plating the front surface and the rear surface of the heat-dissipating base, including the hardened layer formed thereon, with a metal material, and
• a second initial warping including
• plating the front surface and the rear surface of the heat-dissipating base with the metal material to form a plating layer, and
• subsequently performing the shot peening on the rear surface of the heat-dissipating base, including the plating layer formed thereon, with the metal material;
• and
• soldering a laminated substrate, which includes an insulating board and a circuit board provided on a front surface of the insulating board, on the heat-dissipating base after the first or second initial warping at a side of the front surface thereof, and soldering a semiconductor chip on the circuit board.