| 摘要 |
PURPOSE:To obtain a semiconductor device, heat dissipation therefrom is excellent, by bonding a semiconductor chip on a metallic substrate through a cap- shaped intermediate plate in which metals having superior heat conductivity are cladded on both sides of a metal having a small thermal expansion coefficient. CONSTITUTION:A cladding plate consisting of copper, an Invar alloy (64% iron and 36% nickel) and copper is used, and a disk, the constitution of thickness is represented by 1:4:1 and a thermal expansion coefficient thereof in the lateral direction is 6.2X10<-6>/ deg.C, is press-worked, thus forming a cap-shaped intermediate plate 2. In the intermediate plate, structures in side surfaces function so as to prevent the effect of thermal expansion on a bottom of a copper substrate 1, and a thermal strain applied to a solder layer 4 between the intermediate plate 2 and a transistor chip 3 is reduced to force close by stress generated by a thermal expansion coefficient original in the cladding plate. Not more than 1.5mm. is effective as the thickness of the intermediate plate. The thermal expansion coefficient must lie between those of the semiconductor chip 3 and the substrate metal 1, and thermal resistance is also reduced when clad metals have excellent thermal conductivity. |
