Manufacturing method of a semiconductor device

A method of manufacturing a semiconductor device comprising the steps of:

• providing a metal substrate comprising a front surface, a rear surface opposite to the front surface, a chip fixing partition part on the front surface thereof, a depression formed into the rear surface thereof, grooves formed over the front surface, and partition parts surrounded by the grooves, the grooves being formed around the chip fixing partition part, a dimension of each of the partition parts being smaller than a dimension of the chip fixing partition part, and a bottom surface of the depression is substantially the same size as the chip fixing partition part which corresponds to the bottom surface of the depression across the metal substrate;
• providing a semiconductor chip comprising a front surface, a rear surface, electrodes formed on the front surface thereof;
• fixing the semiconductor chip over the chip fixing partition part on the front surface of the metal substrate;
• electrically connecting the electrodes of the semiconductor chip with the partition parts of the metal substrate by conductive wires, respectively;
• forming a resin body which seals the semiconductor chip, the conductive wires, each of the grooves, and the partition parts of the metal substrate;
• after the resin body forming step, etching the rear surface of the metal substrate so that the partition parts are separated from each other and a part of the resin body formed in the each of the grooves is protruded from a level of the etched rear surface of each of the partition parts, a height of each of the partition parts being lower than a height of the resin body formed in the grooves;
• and
• after the etching step, forming a solder plating film on the etched rear surface of each of the partition parts by a print-plating method, the solder plating film being thicker than a height of the part of the resin body protruded from the level of the etched rear surface of each of the partition parts.