| 摘要 |
PURPOSE:To contrive to upgrade the heat-dissipating property of a semiconductor element by a method wherein a substrate to be mounted, whose mainsurface has been fusion-welded with a copper leaf, is rolled by a roller and after the surface of the copper leaf was flattened, the semiconductor element is mounted on the substrate. CONSTITUTION:When a copper leaf is fusion-welded on a ceramic substrate 1, the substrate 1 is heated close to the melting point of the copper leaf. At that time, a crystallization is promoted and grooves 7 are created in the crystal grain boundary by a chemical treatment to be performed for soil removing. The substrate 1 is rolled by a roller, the crystal grains are pressure-broken, the grooves 7 in the crystal grainboundary are filled and the surface of the copper leaf is flattened. After that, when a soldering is performed, the area of blow-holes in the solder is reduced as little as about 10%, because the surface is flat. This method is effective for upgrading the characteristics of the product, is simpler than in the case of a metal plating, and generates no trouble such as stripping. |
