Semiconductor device mounted on heat sink having protruded periphery

A semiconductor device, comprising:

• (a) a board having a first main surface and a second main surface opposite to the first main surface, the board including a through-hole reaching the second main surface from the first main surface, a plurality of first electrodes formed around the through-hole on the first main surface, a plurality of second electrodes formed around the through-hole on the second main surface, and a heat sink disposed inside the through-hole;
• (b) a semiconductor chip having a third main surface, on which a plurality of third electrodes are formed, and mounted on an upper surface of the heat sink;
• (c) a plurality of conductive wires electrically connecting the plurality of third electrodes of the semiconductor chip and the plurality of first electrodes of the board;
• (d) a sealing portion for sealing the semiconductor chip and the plurality of conductive wires;
• and
• (e) a plurality of external terminals formed on the plurality of second electrodes of the board, respectively,
• wherein a thickness of the heat sink is larger than a thickness of the board,
• the heat sink has a protruded portion protruding to outside from a side surface of the heat sink in a peripheral edge portion of the upper surface of the heat sink, and
• the protruded portion is located on the first main surface of the board outside the through-hole, and a lower surface of the protruded portion contacts to the first main surface of the board.