| 摘要 |
PROBLEM TO BE SOLVED: To provide a lead-free solder alloy having excellent falling impact resistance, to provide a solder ball using the lead-free solder alloy, and to provide an electronic member having a solder bump using the lead-free solder alloy. SOLUTION: The lead-free solder alloy has a composition comprising, by mass, 1.0 to 2.0% Ag, 0.3 to 1.0% Cu, 0.005 to 0.10% Ni, 0.0001 to 0.005% Fe and 0.005 to 0.10% Co, and the balance Sn. By the further incorporation of Ni, Fe and Co, a Cu atom site in a Cu<SB>6</SB>Sn<SB>5</SB>intermetallic compound layer produced on the grain boundary with an electrode can be substituted for atomic species having an atomic radius smaller than that of Cu, so as to relax the strain of the Cu<SB>6</SB>Sn<SB>5</SB>intermetallic compound, thus the fracture generated on the grain boundary between a Cu<SB>3</SB>Sn intermetallic compound and the Cu<SB>6</SB>Sn<SB>5</SB>intermetallic compound can be prevented. COPYRIGHT: (C)2007,JPO&INPIT |
