| 摘要 |
PURPOSE:To reduce deformation and breakdown of a metal plate to be welded with pressure, by enlarging the opening angle of the outer compressing surface of an annular compressing part, which is protruded in a trapezoidal shape, in a pressure welding die, so that said opening angle is larger than a specified angle. CONSTITUTION:In a sealing process of a flat type power semiconductor device, which is sealed by cold welding in an airtight manner, an opening angle of an outer compressing surface theta1 of the trapezoidal compressing part of a pressure welding die 12 is made larger than 140 deg.. Thus, warping of the outer surface part of a metal plate to be pressure-welded 3 is eliminated. The outer parts of a pair of the metal plates are contacted, and the opening between the metal plates can be substantially eliminated. Therefore, probability of deformation and breakdown of the outer surface part of the metal to be pressure-welded cab be remarkably decreased, and the mechanical strength of the device can be improved. |
