| 摘要 |
PROBLEM TO BE SOLVED: To provide a multi-layer-plated lead wire and a lead frame containing no noxious lead at all by plating antimony, indium, or bismuth at a specific thickness on the surface of a raw material via tin plating at a specific thickness. SOLUTION: A backing layer 3 of Sn plating is formed at the thickness 3-8μm on a metal strand 2, a surface layer 5 of Sb, In, or Bi plating is formed at the thickness 1-5μm, and the total plating thickness is set to 10μm or above to form a lead wire 1. The minimum plating thickness of the backing layer 3 capable of exerting the connecting effect of the lead wire 1 is 3μm, and the possibility that whiskers are generated is increased when the plating thickness exceeds 8μm. The minimum plating thickness of the surface layer 5 for forming the prescribed alloy via the diffusing action is 1μm, and the increase of the connecting effect is small even when the plating thickness exceeds 5μm. When the total plating thickness becomes 10μm or above, the connecting effect of the lead wire 1 can be sufficiently exterted generally. |
