The present invention provides a semiconductor device which comprises a lead frame including a die pad having one or two or more openings, a substrate mounted over the die pad so as to expose a plurality of semiconductor chip connecting second electrode pads from the openings of the die pad, a plurality of semiconductor chips mounted over the die pad and the substrate, bonding wires that connect chip electrode pads of the semiconductor chip and their corresponding semiconductor chip connecting first and second electrode pads of the substrate, and a sealing portion which covers these and is provided so as to expose parts of leads.