IMC of SAC0307-xNi/Ni soldered joint and consumption of Ni coating

The microstructure of interfacial IMC and the consumption of Ni layer for SAC0307/Ni(Sn-0.3Ag-0.7Cu/Ni) soldered joint and SAC0307-0.05Ni/Ni(Sn0.3Ag-0.7Cu-0.05Ni/Ni) soldered joint after aging at 180℃ were studied by scanning electron microscope(SEM).The results indicated that the IMC layer of SAC0307/Ni and SAC0307-0.05Ni/Ni are both(Cu_1-xNi_x)₆Sn₅ after reflow soldering.With the increasing of aging time, the thickness of IMC layer increases gradually, the type of IMC is not changed, but the chemical composition changes.The morphology of IMC is storm-shaped and the thickness of IMC is much thinner when SAC0307 solder added 0.05% Ni is used.The consumption of Ni layer is nearly the same using both solders after the first time reflow soldering, but the residual thickness of the Ni layer in SAC0307/Ni solder is thinner than that in SAC0307-0.05Ni/Ni after aging for 384 h.So solders with a little Ni element can decrease the consumption rate of Ni layer effectively during aging, that is, the aging-resistant ability of Ni pad is improved obviously.