Patent ID: 7675153

Claim:
A semiconductor device comprising: a circuit board having external connection electrodes; and a plurality of semiconductor chips which are stacked and mounted on the circuit board and each of which is mounted on the circuit board by means of wire bonding, wherein at least one of the semiconductor chips stacked on the circuit board includes: bonding pads which are arranged on a main surface thereof along at least one side of the semiconductor chip and electrically connected to semiconductor elements, overhung portions formed in positions of a backside of the semiconductor chip corresponding to the bonding pads, each having a start point inside the bonding pad, formed to have a surface which becomes thinner in a direction toward an outer periphery to an end point which reaches a side wall thereof, and forming a space to accommodate ball bonding portions between at least one of the overhung portions and a main surface of a semiconductor chip arranged in a lower stage, and insulating layers which are formed to cover the overhung portions and prevent contact with bonding wires of the semiconductor chip arranged in the lower stage, the semiconductor device further comprising: insulating members which fill gaps defined by the overhung portions between the stacked semiconductor chips, and also fix and seal the ball bonding portions; and a package which seals the stacked semiconductor chips, the insulating members, the bonding wires, and a mounting surface side of the circuit board, wherein the surface of each of the overhung portions is mirror-finished.