Effect of Electromigration on Interfacial Reactions in 90Sn-10Sb Pb-Free Solder Joints

The electromigration effect on interfacial reactions in Cu/90Sn-10Sb/Cu Pb-free solder joints was investigated under electric current stressing. The growth of the Cu 3 Sn and Cu 6 Sn 5 intermetallic compound (IMC) layers was enhanced at the anode but inhibited at the cathode, compared with the no-current case. The growth of the IMC at the anode followed a parabolic law. Upon increasing the temperature to about 140°C, the thickness of the Cu 6 Sn 5 IMC at the anode increased significantly. Sn 3 Sb 2 IMC coarsened in the Cu 6 Sn 5 IMC at the anode and in the β-Sn at the cathode. The possible mechanism of the electromigration effect is discussed.