| 摘要 |
A lead-free solder material is provided, which shows a high thermal fatigue resistance and is able to effectively reduce occurrence of connection failure that would cause a function of a product to stop. A solder material comprises 1.0-4.0% by weight of Ag, 4.0-6.0% by weight of In, 0.1-1.0% by weight of Bi, 1% by weight or less (excluding 0% by weight) of a sum of one or more elements selected from the group consisting of Cu, Ni, Co, Fe and Sb, and a remainder of Sn. When a copper-containing electrode part (3a) of an electronic component (3) is connected to a copper-containing electrode land (1a) of a substrate (1) by using this solder material, a part (5b) having an excellent stress relaxation property can be formed in the solder-connecting part and a Cu-Sn intermetallic compound (5a) can be rapidly grown from the electrode land (1a) and the electrode part (3a) to form a strong blocking structure. Thus, even in a severe temperature environment, cleavage can be prevented from generating and extending, a high thermal fatigue resistance can be attained, and occurrence of connection failure can be reduced. |
