The Successive-Initiation Modeling Strategy for Modeling Damage Progression: Application to Voided Solder Interconnects

This study presents simulation of damage initiation and propagation in solder joints with voids, under thermo-mechanical loading. A three dimensional, global-local, visco-plastic FEA is conducted for a CTBAG132 assembly under thermal cycling. The displacement results of the global FEA at the top and bottom of the critical solder ball are used as the boundary conditions in a local model which focuses on the details of the critical solder ball. The local model is error-seeded with voids of different sizes and locations. A continuum cyclic creep-fatigue damage model based on energy-partitioning is used as the damage criterion. A method of successive initiation is used to model the growth of damage in critical solder joint. Damage growth is monitored for all cases. The study is conducted for voids of different sizes located close to the damage initiation site and propagation path. The results show that damage initiation life is a non-monotonic function of void size, peaking at a void area fraction of approx 15%. Propagation life, however, is a monotonic function of void size and decreases as voids become larger