Power semiconductor device for surface mounting

A power semiconductor device, which comprises:

• at least one semiconductor wafer;
• a metal mounting plate having a central portion, said semiconductor wafer being mounted in thermal and electrical contact with said central portion;
• a body of isolating material on said central portion and enveloping said wafer;
• a heat-dissipating portion of said metal plate alongside said central portion and extending laterally from a first side of said body;
• conducting pins extending longitudinally from a second, opposite side of said body and extending downwardly to a level below that of said metal plate;
• legs formed from parts of said heat-dissipating portion and extending perpendicularly downward below said metal plate in a direction away from said body, said legs and said pins projecting substantially the same distance below said metal plate;
• and
• said legs extending a distance below the lower surface of said metal plate such that, during a surface mounting operation of the device by wave soldering on a substrate, a quantity of solder is enclosed by a capillary effect under the heat-dissipating portion of said metal plate, covers a major part of the lower surface of said heat-dissipating portion and is in electrical and thermal contact with a metallized portion of said substrate.