| 摘要 |
PURPOSE:To improve thermal stress absorption and heat dissipation, to reduce a cost of an igniter and to increase its life by suitably setting a thickness of high temperature solder without using a thermal stress relaxation material such as an Mo sheet on a power transistor laminated part of various types of power semiconductor devices such as an igniter. CONSTITUTION:In an igniter, a power transistor chip 1, an insulating aluminum board 3 are laminated on an aluminum base 5, and a control IC board 6 is placed on the base 5. The board 3 is connected to the base 5 by solder 4 containing 50:50 of Pb:Sn, and the chip 1 is connected to the board 3 by high temperature solder 2 containing 90% or more of Pb. The thickness of the solder 2 is computer-analyzed from a viewpoint of its life, and its thickness is set to 0.15-0.25m, which was heretofore about 0.1mm so as to provide a function of thermal stress relaxation. |
