| 摘要 |
PURPOSE:To eliminate the fatigue of solder caused by variation of temperature as well as to rapidly discharge the heat generated by a heating electronic element by providing an alloy material part consisting of Cu-W alloy on the side for element mounting of the mounting circuit board. CONSTITUTION:The semiconductor device is composed of a mounting circuit board 3 which is composed of a frame part 1 made of Cu and a Cu-W alloy material 2 laminated thereon and a heating electronic element 5 fixed to said circuit board 3 through a solder layer 4. The Cu-W alloy composing the alloy material part 2 has a linear expansion coefficient close to that of Si composing the element 5 and further has a good heat conductivity. Accordingly, the repeating stress to be generated in the solder layer 4 is reduced by the alloy material part 2 so that the layer 4 can be formed extremely thin. Then, a heat resistance due to poor heat conductivity of the layer 4 is substantially reduced as well as the fatigue of the solder is prevented by the alloy material part 2.
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