| 摘要 |
PROBLEM TO BE SOLVED: To provide a composition of a solder alloy comprising 0.3 to 0.7 wt.% Cu, 0.04 to 0.1 wt.% Ni and the balance Sn which suppresses generation of micro-cracks and exerts more excellent soldering characteristics, and further imparts a fine structure to the soldered alloy after solidification. SOLUTION: The solidification mode of a Sn-Cu alloy is remarkably changed by addition of Ni, and an alloy having the composition of 0.6 to 0.7% Cu, 0.05 to 0.06% Ni most remarkably changes the solidification mechanism. When Ni is not added, the solidification advances from other contact positions. On the other hand, when an alloy has the above composition, its solidification progresses not only from other contact positions but uniformly progresses, and the soldered alloy after solidification has a fine structure so that dense and uniform solidification obtained can suppress generation of micro-cracks. COPYRIGHT: (C)2007,JPO&INPIT
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