According to the method of manufacturing a semiconductor device, a lead frame is provided wherein the thickness of a tab-side end portion of a silver plating for wire connection formed on each suspending lead 1e is smaller than that of a silver plating formed on each lead. Thereafter, a semiconductor chip is mounted onto a tab. In this case, since the entire surface of the silver plating on the suspending lead 1e is in a crushed state, it is possible to prevent contact of the semiconductor chip with the silver plating when mounting the chip onto the tab. Consequently, in a die bonding process, the semiconductor chip can slide on the tab without contacting the silver plating and thereby making it possible to diminish damage to the semiconductor chip when mounted onto the tab and hence to possibly prevent cracking or chipping of the chip when assembling the semiconductor device.