Study on thermal fatigue characteristics of lead-free SAC305 solder joint by RPC

Preparation of BGA micro-joint with single-double substrates used by SAC305 lead-free solder is fabricated by reflowing process based on substrate FR-4. The microstructure change and evolution law of the solder joints are studied through the method of rapid thermal fatigue. The single-base plate SAC305/Cu solder joint was tested at extreme temperature 60-200°C by rapid thermal cycle 24 hours and 36 hours respectively, it was found the IMC grow by the zigzag shape, and fatigue cracks 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.