| 摘要 |
<p>PURPOSE:To reduce the electric resistance and improve the tensile strength, bending work and solder weather resistance by a method wherein the base metal of lead terminals in a semiconductor device is formed by adding by restricting a part of Cr and Zr to Cu as the main constituent and being Sn plated. CONSTITUTION:The metallic base is formed by adding at least one kind of Cr or Zr to Cu as the main constituent. The amount thereof is set 0.3<=Cr+Zr<=2 in weight %, wherein the amount of Cr does not exceed 1.5%, and that of Zr does not exceed 1.0%. Further, as the coating substance, Sn is applied to coating by means of plating, etc. The thickness of this coating is thickened to a value more than 2mum. The reason why Cr is restricted to the range of approx. 0.3- 1.5 in weight % is from the relation between the Sn coating layer, and the upper limit is restricted to 1.5% because of easy segregation of Cr. When Cr is in a large amount, the conductivity is more or less decreased, but it is little problem for this kind of electronic part, and accordingly the strength is improved resulting in the improvement of the reliability.</p> |
