US Patent 7541667 Semiconductor device and method of manufacturing the same

A manufacturing method of a semiconductor device including preparing a lead frame having a die pad, leads arranged around the die pad and a silver plating layer formed over a first portion of each of the leads, mounting a semiconductor chip over a main surface of the die pad with a rear surface of the chip fixed to the main surface of the die pad, electrically connecting electrodes of the chip with the leads through wires, forming a molding resin sealing the die pad, the first portion, the semiconductor chip, and the wires, and forming a lead-free solder plating layer over a second portion of each of the leads exposed from the molding resin. An area of the die pad is smaller than an area of the chip, and a part of the molding resin contacts with the rear surface of the chip exposed from the die pad.