| 摘要 |
PURPOSE:To prevent oxidation and deterioration of a tin plating film, carry out excellent bonding and prevent the generation of whisker by covering the tin plating film or the soldering film and thereby forming a gold plating film. CONSTITUTION:A tin plating film 14 is formed on an inner lead 12 and an outer lead 13. A gold plating film 16 is further formed on the tin plating film 14. As the tin plating film 14 is covered with the gold plating film 16, it is possible to prevent deterioration caused by the oxidation of the tin plating film 14 or the like and it is also possible to prevent the growth of whisker from the tin plating film 14. Furthermore, the gold plating film 16 itself is extremely stable, which makes it possible to carry out excellent bonding. Especially, the jointing of the inner lead 12 to a semiconductor device is carried out by gold-tin eutectic alloy between the tin plating film formed on the inner lead 12 and a gold bump formed on the semiconductor device. However, it is necessary to form the thickness of the gold plating film 16 so that it may not hinder the formation of gold-tin eutectic alloy. |
