| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance bonding strength between a lead frame member and a heat plate by coating one or both of an inner lead and the heat plate to be jointed with tin or a tin alloy and then welding them by YAG laser. SOLUTION: A lead frame 1 comprises a part 2 for mounting a semiconductor chip 5, a lead frame member 3 of copper alloy having an inner lead 3a for connection with electrodes on the semiconductor chip 5 and an outer lead for connection with a printed wiring board, or the like, and a heat plate 4 of copper alloy disposed beneath the inner lead 3a. One or both of the inner lead 3a and the heat plate 4 is subjected in advance to plating of tin or tin allay and coated with a plating layer 7 of tin or tin alloy. Subsequently, the inner lead 3a and the heat plate 4 are welded at the part to be jointed by Nd<3+> YAG laser light.</p> |
