Patent ID: 8456001

Claim:
A pressure-contact semiconductor device comprising: a semiconductor substrate having a pair of electrodes on a front side and a back side thereof, respectively; a pair of thermal buffer plates and a pair of main electrode blocks, each electrode block having a first flange, being provided opposed to the respective electrodes on the semiconductor substrate such that the substrate is sandwiched therebetween, the main electrode blocks respectively having first outer peripheral surfaces and second outer peripheral surfaces, the first outer peripheral surfaces having diameters larger than those of the second outer peripheral surfaces, steps being formed between the first and second outer peripheral surfaces of the main electrode blocks; an insulating container provided between the first flanges of the main electrode blocks, surrounding the semiconductor substrate, and having second flanges respectively connected to each of the first flanges; O-rings, circular in shape and cross section and having innermost surfaces with inner diameters larger than a diameter of the semiconductor substrate, said innermost surfaces respectively provided in contact with the second outer peripheral surfaces of each of the main electrode blocks so that the O-rings are in contact with the steps; and a hollow cylindrical insulator, separated from the insulating container provided in contact with the O-rings, for shielding the semiconductor substrate from the second flanges and the insulating container in cooperation with the main electrode blocks and the O-rings; the semiconductor substrate being sealed in a gastight space created by joining the insulating container to the second flanges which are connected to the first flanges, wherein the first outer peripheral surfaces and the second outer peripheral surfaces are in the gastight space, the steps clamp the hollow cylindrical insulator via the O-rings, the hollow cylindrical insulator is fitted across anode and cathode sides of the second outer peripheral surfaces so that the respective O-rings are pressed against the steps in vertical directions toward the semiconductor substrate.