Patent ID: 7943427

Claim:
A method of producing a semiconductor device, comprising the steps of: preparing a substrate for use in production of a semiconductor device, which substrate includes an adhesive sheet having a base layer and an adhesive layer provided on the base layer, and a plurality of electrically conductive portions provided on the adhesive layer of the adhesive sheet, wherein each electrically conductive portion includes a metal foil comprising copper or a copper alloy, and plating layers for an electrically conductive portion, the plating layers being provided on upper and lower portions of the metal foil, and wherein the plating layers for each electrically conductive portion provided on the upper and lower portions of the electrically conductive portion constitutes an overhanging portion which overhangs outside from the metal foil, and wherein the plating layer of the electrically conductive portion on the lower portion of the metal foil is embedded within the adhesive layer of the adhesive sheet; fixing each semiconductor element having electrodes onto the adhesive layer of the substrate for use in production of the semiconductor device, and electrically connecting the electrically conductive portions and the electrodes of the semiconductor element with wires while the plating layer of the electrically conductive portion on the lower portion of the metal foil is embedded within the adhesive layer of the adhesive sheet; sealing the semiconductor element, wires and electrically conductive portions by using a sealing resin while the plating layer of the electrically conductive portion on the lower portion of the metal foil is embedded within the adhesive layer of the adhesive sheet; separating the adhesive sheet from the sealing resin, wherein before the adhesive sheet is separated from the sealing resin, the plating layer of the electrically conductive portion on the lower portion of the metal foil is embedded within the adhesive layer of the adhesive sheet; and dividing the sealing resin into an individual piece for each semiconductor element.