| 摘要 |
PROBLEM TO BE SOLVED: To reduce the possibility of outer leads from being separated off from a wiring board, when a semiconductor chip is connected in an outer lead- annexed wiring board where chip connecting therminals are formed of gold-tin solder. SOLUTION: Outer leads 21 are connected to outer lead connecting terminals 5 with a gold-tin solder 5h which is higher than a gold-tin solder 3h in liquids temperature. As gold-tin solder bumps 3h are low in liquids temperature, the outer leads 21 are restrained from being separated off, even if they are heated when a semiconductor chip is connected. Moreover, both the chip connecting terminals 3 and the outer lead connecting thermals 5 are plated with both gold and tin which are thick enough to become gold-tin eutectic solder, the gold-plate outer lead 21 is made to bear against the lead connection terminal 5, and the outer leads 21 and the connection terminals 5 are properly heated above a temperature at which a gold plating layer and a tin plating layer react on each other to become eutectic. |
