A semiconductor package includes at least four lead frames each having an extending portion and a connecting portion, a heat dissipation plate having a top surface and a bottom surface, at least one semiconductor chip positioned on the top surface of the heat dissipation plate. At least one conductive wire electrically connects the chip to the lead frames. An encapsulation covers the lead frames, the heat dissipation plate, the semiconductor chip, and the conductive wires, while the bottom surface of the heat dissipation plate and the extending portions of the lead frames are exposed.