| 摘要 |
PURPOSE:To improve the solderability of the titled lead frame as well as to reduce the adverse effect inflicting on a semiconductor element and the like by a method wherein a copper-alloy plated film of a copper-tin alloy, copper- zinc-tin alloy, or copper-zinc alloy is formed on an external lead part. CONSTITUTION:The necessary plated film such as a precious metal plated film and the like is partially plated on a stage 2 and the external surface of the tip of an inner lead part 3, and a copper alloy plated film 7 of a copper-tin alloy, a copper-zinc-tin alloy, or a copper-zinc alloy is formed on the external surface of an external lead part 4. An oxide film is grown on the film 7 by experiencing a thermal hystereses in an assembling process, but this oxide film can be removed easily using a weak flux. The weal flux can be effectively used in the oxide film removing process which is performed as the treatment to be performed before a solder dipping operation, and the problem of lowering of reliability of the semiconductor device can be removed. Moreover, the external lead part formed as above has an excellent solderability, and also the corrosion-resisting property of the above-mentioned alloy film is also excellent. |
