A semiconductor device includes a solder dam for restricting the flow of solder during manufacturing. The device includes a semiconductor chip bonded to a first side of a circuit board, a metal base for dissipating heat produced by the semiconductor chip, the metal base being bonded to a second side of the circuit board, and a dam material disposed on the metal base in a predetermined pattern for restricting the flow of solder used in bonding a plurality of the circuit boards to the metal base. By employing the solder dam, solderability is not impaired, device contamination can be avoided, and a highly reliable semiconductor device can be produced.