Abstract：The great difference of the failure modes between lead-containing and lead-free solder joints subjected to drop impact loading has not been well understood. In this paper, a feasible finite element approach is proposed to model the cracking behavior of lead-containing and lead-free solder joints under drop impact loading. In the model, the damage at the intermetallic compound layer/solder bulk interface is calculated by the cohesive zone model, and the failure in the intermetallic compound layer is evaluated by computing the energy release rate. The numerical simulation result shows that, for the lead-containing Sn37Pb solder joint, the damage in the intermetallic compound layer/solder bulk interface initiates earlier and much greater than that in the lead-free Sn3.5Ag solder joint. This damage can relieve the stress in the intermetallic compound layer and reduce the risk of intermetallic compound layer fracturing in the lead-containing Sn37Pb solder joint.
2013, Vol. 34 
