| 摘要 |
PROBLEM TO BE SOLVED: To provide a lead-free solder of the workability, working condition, and soldering reliability equivalent to those of a conventional Sn-37 wt.% Pb eutectic solder, and a package product using the solder. SOLUTION: In the solder having a composition consisting of, by weight, 7-10% zinc,≤6% bismuth,≤0.1% silver and the balance tin, the solidus temperature is not lower than the melting point of Sn-37 wt.% Pb eutectic solder, and the difference between the liquidus temperature and the melting point of the Sn-37 wt.% Pb eutectic solder is around 10-20°C. Therefore, an electronic component can be mounted by using the same reflow furnace as that when using the conventional Sn-37 wt.% Pb eutectic solder. Silver improves the tensile strength, and suppresses generation of undesirable intermetallic compounds. As a result, a package product of more excellent mechanical strength and higher soldering reliability than those of a package product using Sn-37 wt.% Pb eutectic solder is obtained. COPYRIGHT: (C)2004,JPO
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