CLAD STRIP AND ITS PRODUCTION

摘要

PURPOSE:To prevent surely defective plating in a clad strip for an IC lead frame by providing a polished surface on the surface of a base material strip for cladding and forming the polished surface to the width at which said surface is not exposed to the outside of a package. CONSTITUTION:The base material strip 1 for cladding is formed with the polished surface 1A in the central part of the short side direction of the surface by a wire brush. A striped cladding metal 2 is superposed on said strip with the surface 1A as a substrate and both materials are rolled and press-welded. The width of the clad strip is specified to W1>W2 where the width of the surface 1A is designated as W1 and the width of the metal 2 as W2. The clad strip 10 is blanked and bent to a prescribed shape, by which the metal 2 side is formed as an inside terminal part and the exposed part of the strip 1 on the opposite side thereof is formed as a leg-shaped outside terminal part. The inside terminal part and an IC chip are connected by an aluminum wire and this part is covered and protected by the package. The package is W3>W1>W2 if the width thereof is designated as W3.