Patent ID: 7709947

Claim:
A semiconductor device, comprising: an insulating substrate having a planar insulating member and a conductive wiring pattern formed on an upper surface of the insulating member; a semiconductor element having a back electrode which is joined onto the wiring pattern of the insulating substrate, the semiconductor element having at least one electrode on an upper surface of the semiconductor element, the semiconductor element further having an electrode on a bottom surface of the semiconductor element as the back electrode; and an external electrode, the external electrode being implanted to a case and having a main body portion, the main body portion being buried in the case, the external electrode further having at least one joining portion protruding toward the semiconductor element from an inner side of a side wall of the case, the external electrode further having an external terminal, the external terminal being extended from an upper end portion of the case to the outside of the case, the main body portion, the joining portion and the external terminal are formed integrally within one member, the joining portion of the external electrode being directly and ultrasonically joined onto the wiring pattern of the insulating substrate so that the external electrode is electrically connected to the back electrode of the semiconductor element through the wiring pattern of the insulating substrate, the joining portion being formed thinner than the main body portion so that ultrasonic vibration and a load necessary for joining the joining portion onto the wiring pattern can be suppressed, wherein the external electrode has a plurality of branched joining portions and the plurality of joining portions are directly joined onto the wiring pattern of the insulating substrate through ultrasonic joining, respectively.