| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a plating film with which growth of whiskers accompanying an external stress can be effectively suppressed and a method for forming the same. <P>SOLUTION: A tin plating film 13 composed of tin or tin alloy is formed on the front or rear of a base material 11 constituting a lead frame 10. The tin alloy is exemplified by, for example, a tin-copper alloy (content of copper: 2 mass%), a tin-bismuth alloy (content of bismuth: 2 mass%), etc. The base material 11 comprises, for example, a Cu alloy, etc. A plurality of crystal grains are irregularly arrayed in the tin plating film 13. Further, a plurality of void parts 14 exist in the tin plating film 13. Even if bending etc., are thereafter performed, the void parts 14 exist in the tin plating film 13 and therefore, the external stress is released. Consequently, the growth of the whiskers accompanying the external stress is suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
