Crystal Plasticity Simulations of Subgrain Formation in Sn-based Solders During Thermal Cycling

Tin-based solder joints are widely used to provide high-density interconnection in microelectronic packaging. Experiments show that under repetitive temperature cycling, subgrains may nucleate in the tin phase, contributing to early degradation. We present numerical simulations on a board-level packaging stack-up during cool-down and under thermal cycling. A crystal plasticity model and thermomechanical anisotropy are utilized to study the deformation of the solder joints. With this model, we can quantify the contributions to the deformation from the joint location versus the result of thermoelastic anisotropy during thermal cycling.