SOLDERING MATERIAL AND ELECTRONIC COMPONENT ASSEMBLY

摘要

A lead-free soldering material which shows high thermal fatigue resistance and with which it is possible to effectively reduce the occurrence of connection failures that cause a function of a product to stop. The soldering material comprises 1.0-4.0 wt.% Ag, 4.0-6.0 wt.% In, 0.1-1.0 wt.% Bi, up to 1 wt.% (excluding 0 wt.%) the sum of one or more elements selected from a group consisting of Cu, Ni, Co, Fe, and Sb, and Sn as the remainder. When a copper-containing electrode part (3a) of an electronic component (3) is bonded to a copper-containing electrode land (1a) of a substrate (1) with this soldering material, a part (5b) having excellent stress relaxation properties can be formed in the soldering area and a Cu-Sn intermetallic compound (5a) can be rapidly grown from the electrode land (1a) and the electrode part (3a) to form a tenacious blocking structure. Thus, even in a severe temperature environment, cracks can be prevented from generating and propagating and high thermal fatigue resistance can be attained. The occurrence of connection failures can hence be reduced.