Analysis of IMC evolution and nickel plating consumption of SAC305/Ni soldering joints

The study is about the interfacial intermetallic compounds (IMC) microscopic changes and nickel plating consumption on SAC305/Ni soldering joints (with four solder diameters: 200, 300, 400, 500μm) before and after isothermal aging at 160°C by scanning electron microscopy (SEM). The results indicated that the IMC are mainly the (Cu, Ni)₆Sn₅ of SAC305/Ni soldering joints after reflow. After aging, the thickness of IMC layer increases, and the larger the soldering joint size, the greater the IMC growth rate. After reflow and aging, the thickness of interfacial IMC layer is thinning with the increasing of the soldering joint size. The remaining thickness of nickel plating is thinning with the aging time prolonging. After reflow, the remaining nickel plating is thinner with the increase of the soldering joint size. After aging 96-600h, with the increase of the soldering size, the remaining thickness of the nickel plating layer is thicker.