The effects of Ni addition on microstructure evolution and mechanical properties of solder joints undergoing solid-liquid electromigration

The effect of solid-liquid electromigration on Cu-xNi/Sn-3.0Ag-0.5Cu/Cu-xNi (x = 0, 1.5 and 5 wt%) joints bonded at 260 degrees C with electric density of 2.89 x 10(2) A/cm(2) was investigated. The results showed that intermetallic compounds (IMCs) performed a non-interfacial growth in the Cu-5Ni/SAC305 system. The electron backscatter diffraction (EBSD) analysis revealed that the orientation of the Cu6Sn5 [1 0 0] direction parallelled to the direction of electric current, however, the addition of Ni could induce that the growth of (Cu,Ni)(6)Sn-5 grain exhibited isotropy. Additionally, the additional Ni resulted in significant reduction in grain size and enhancement in the tensile strength of joints. (C) 2019 Elsevier B.V. All rights reserved.