Cyclical behavior of lead-free BGA soldered joints based on nano-indentation method

Through the cycle loading test of nano-indentation method, the effects of maximum load, cycle number and holding time for two kinds BGA soldered joints of Sn-3.0Ag-0.5Cu and Sn-0.3Ag-0.7Cu on cycling performance were investigated.The results indicated that the cycling performance of Sn-Ag-Cu series lead-free BGA soldered joints was load-dependent, and the cumulative damage of BGA soldered joints increased with the increasing of maximum load, especially largely accumulated in the first few cycles, then gradually decreased and stabilized.However, with the cycle number increasing, the deformation resistance of BGA soldered joints slightly decreased;the creep displacement increased with the holding time being increased and the creep-fatigue interaction will accelerate the failure of BGA soldered joints.The energy loss of Sn-0.3Ag-0.7Cu BGA soldered joints is greater than that of the Sn-3.0Ag-0.5Cu BGA solder joints.