Research on microstructures of double interfaces SAC305 solder joint by RPC

BGA micro-joint with double substrates used by SAC305 lead-free solder is fabricated by reflowing process based on substrate FR-4. The microstructures of the solder joints are studied through the method of rapid thermal cycling (RPC). The double-based plate Cu/SAC305/Cu solder joint was tested at extreme temperature 60-180 °C by rapid thermal cycling 48 hours and 72 hours respectively, it was found the IMC grow by the zigzag shape, and fatigue cracks greatly appear at the interface of IMC/Cu, they are initiating and propagating along the boundary, and thread through the cross section of solder joint in the end, which lead to the failure of solder joint.