基于纳米压痕法的无铅BGA焊点的循环力学行为

采用纳米压痕法通过循环加载卸载方式研究了最大载荷、循环次数及保载时间对Sn-3.0Ag-0.5Cu和Sn-0.3Ag-0.7Cu 2种钎料BGA焊点循环性能的影响.结果表明,Sn-Ag-Cu系无铅BGA焊点的循环性能具有很大的载荷依赖性,随着最大载荷的增加,BGA焊点的损伤累积增加且前几周循环中损伤累积很大,其后逐渐减小并趋于稳定;循环次数增加,使BGA焊点抵抗变形的能力稍有降低;保载时间增加,蠕变位移不断增加,蠕变和疲劳共同作用会加速焊点失效;Sn-0.3Ag-0.7Cu钎料BGA焊点的能量损耗大于Sn-3.0Ag-0.5Cu钎料BGA焊点.

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.