| 摘要 |
PROBLEM TO BE SOLVED: To improve wettability of Sn-Si base alloy so as to newly obtain lead-free Sn-Si alloy solder having good jointability whose melting point is lower than an eutectic point of Sn-Ag alloy by containing a specific volume of bismuth, silver, copper, and nickel while tin is used as a main component. SOLUTION: This invention relates to Sn-Bi base alloy, whose main component is Sn, which includes 21 wt.% or less Bi, 4 wt.% or less Ag, 2 wt.% or less (including 0) Cu, and 0.2 wt.% or less Ni, and whose melting point is lower than 221 deg.C, the eutectic point of Sn-Ag alloy. It is preferable that the Sn-Bi base alloy is mainly composed of Sn and includes 21 wt.% or less Bi, 4 wt.% or less Ag, 2 wt.% or less (including 0) Cu and 0.1 wt.% Ge, or is mainly composed of Sn and includes 21 wt.% or less Bi, 4 wt.% or less Ag, 2 wt.% or less (including 0) Cu, 0.2 wt.% or less Ni, and 0.1 wt.% or less Ge. Thereby, heat resistance and fatigue strength are also improved.
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