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.