高温时效下无铅焊料Sn-3.5Ag-X (X =0, 0.75Ni, 1.0Zn, 1.5In)合金与Cu板焊接界面金属间化合物的微观演变

In this paper, the microstructural evolution of IMCs in Sn-3.5Ag-X (X=0, 0.75Ni, 1.0Zn, 1.5In)/Cu solder joints and their growth mechanisms during liquid aging were investigated by microstructural observations and phase analysis. The results show that two-phase (Ni3Sn4 and Cu6Sn) IMC layers formed in Sn-3.5Ag-0.75Ni/Cu solder joints during their initial liquid aging stage (in the first 8 minutes). While after a long period of liquid aging, due to the phase transformation of the IMC layer (from Ni3Sn4 and Cu6Sn phases to a (Cu, Ni)6Sn5 phase), the rate of growth of the IMC layer in Sn-3.5Ag-0.75Ni/Cu solder joints decreased. The two Cu6Sn5 and Cu5Zn8 phases formed in Sn-3.5Ag-1.0Zn/Cu solder joints during the initial liquid aging stage and the rate of growth of the IMC layers is close to that of the IMC layer in Sn-3.5Ag/Cu solder joints. However, the phase transformation of the two phases into a Cu-Zn-Sn phase speeded up the growth of the IMC layer. The addition of In to Sn-3.5Ag solder alloy resulted in Cu6(Snx, In1-x)5 phase which speeded up the growth of the IMC layer in Sn-3.5Ag-1.5In/Cu solder joint.