Electromigration-induced microstructural evolution in lead-free and lead–tin solders
K-L. Lin, National Cheng Kung University,Taiwan
The electromigration-induced microstructural variation at the joint interface and within the bulk of Pb-free and Pb–Sn solders is examined. The accumulation of solder alloy elements accelerates the interfacial reaction and thus the formation of interfacial intermetallic compound. The formation of intermetallic compound results in stress accumulation and enhances whisker growth within the solder. The torque induced by electron wind results in grain rotation of the solder bulk. The current stress causes the dissolution and thus supersaturation of second phase in the matrix, for example Zn in Sn ...