Semiconductor device with radiation plate for high radiation character and method of manufacturing the same

A semiconductor device comprising:

• a semiconductor pellet having a plurality of electrode pads;
• a radiation plate having said semiconductor pellet mounted thereon;
• a plurality of lead terminals each connected with each of said electrode pads by means of a bonding wire;
• and
• a resin member having a first surface and a second surface, said resin member encapsulating said semiconductor pellet, a part of said radiation plate, said bonding wires and a part of each of said lead terminals;
• said radiation plate comprising a unitary substantially rectangular structure including,
• a central portion,
• two opposing side portions, and
• two opposing end portions,
• said central portion rising convexly through step portions from the first surface of said resin member to the level of said two opposing side portions, and
• said two opposing side portions rising concavely through step portions to the level of said two opposing end portions at the second surface of said resin member;
• wherein the central portion of said radiation plate is exposed to the outside from the first surface of said resin member and said two end portions are exposed to the outside from the second surface of said resin member.