| 摘要 |
PROBLEM TO BE SOLVED: To provide a lead-free solder alloy achieving satisfactory performance regarding 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 and 0.005 to 0.07% Ni, and the balance Sn with inevitable impurities. In an Sn-Ag-Cu based solder joint on a Cu electrode, a layer of a Cu<SB>3</SB>Sn intermetallic compound is formed directly on the Cu electrode, and, a Cu<SB>6</SB>Sn<SB>5</SB>intermetallic compound layer is formed thereon. By substituting the Cu atom site in the Cu<SB>6</SB>Sn<SB>5</SB>intermetallic compound layer for Ni having an atomic radius smaller than that of Cu, the strain of the Cu<SB>6</SB>Sn<SB>5</SB>intermetallic compound layer is relaxed, thus the impact resistance of the solder joint can be improved. COPYRIGHT: (C)2007,JPO&INPIT |
