| 摘要 |
PURPOSE:To prevent cracks from generating in a brazing metal for connecting a semiconductor element and a metal substrate and to prevent the brazing metal from being deteriorated by a method wherein the thermal expansibility of the metal sub strate is shrinked to a thermal expansibility approximated to the thermal expansibility of the semiconductor element by making the metal substrate into a three-layer structure of an Al plate, an invar and an Al plate. CONSTITUTION:A metal substrate 1 is formed in a way that each plate of an Al plate 2, an invar 3 and an Al plate 2 is performed a cladding treatment by a roller having a pressure of 10-30 ton/cm<2> or thereabouts in the ratio of 1:3:1, for example, and are punched in the prescribed size in a press working after being stretched until they are formed in the prescribed thickness in a rolling process. An anodizing treatment is performed on the surface of the substrate 1 and an Al oxide film 4 is formed. By making the metal substrate 1 in the three-layer structure of the Al plate 2, the invar 3 and the Al plate 2 in such a way, the thermal expansibility (alpha) of the metal substrate 1 becomes 6.6X10<-6>/ deg.C and the difference between the thermal expansibility (alpha) and the thermal expansibility (alpha), 2.4X10<-6>/ deg.C, of a semiconductor element 6 can be shrinked. As a result, cracks due to a temperature cycle are stopped from generating in the brazing metal of the connecting part of the semiconductor element and the metal substrate. |
