Semiconductor module

#1. Field of the Invention

#The present invention relates to a semiconductor module, and more specifically, relates to a structure for connecting a power device chip and an external electrode.

#2. Description of the Background Art

#FIG. 1 is a sectional view showing the structure of a semiconductor module of a first preferred embodiment;

#FIG. 2 is a sectional view showing the structure of a semiconductor module of a second preferred embodiment;

#FIG. 3 is a sectional view showing the structure of a semiconductor module of a third preferred embodiment; and

#First Preferred Embodiment

#FIG. 1 is a sectional view showing the structure of a semiconductor module of a first preferred embodiment. The semiconductor module includes a base plate 1 made of metal such as copper, aluminum and AlSiC, and an insulating substrate joined onto the base plate 1 through solder 31. The structure of the insulating substrate is such that patterns of metal such as copper or aluminum are formed on opposite sides of a ceramic insulating plate 2 by etching technique. A metal pattern 21 is formed on the rear surface of the insulating plate 2, and the metal pattern 21 is joined through solder 31 to the base plate 1. Metal patterns 22 and 23 are formed on the front surface of the insulating plate 2. A power device chip 3 that may be an IGBT or an MOSFET, and a free-wheeling diode chip 4 are joined on the metal pattern 22 through solder 32 and solder 34 respectively.

#A lead frame 5 is joined on the power device chip 3 and the free-wheeling diode chip 4 through solder 33 and solder 35 respectively to connect the power device chip 3 and the free-wheeling diode chip 4 in parallel. The lead frame 5 has one end joined to the power device chip 3, and the opposite end joined to the metal pattern 23 through solder 36. Using copper as the lead frame 5 can enhance the resistance of the lead frame 5 itself to heat.