Sensitivity of the structural behavior of SAC305 interconnects on the variations of creep parameters

Lead-free soldering materials have been of great interest in the field of advanced microelectronic packaging during the last decade. Compared to the eutectic tin-lead solder (Sn-Pb), the increased melting temperature influences mechanical properties that can compromise the integrity of the solder joint in a long period of working time. In the present work, a two-dimensional (2-D) Fan out Wafer Level Packaging structure was modelled with SAC305 for the soldering material. Anand creep model was utilized for the solder balls using different solder interconnect material properties determined for SAC305 taken from different literature sources. The 2-D model of the package was subjected to a cyclic thermo-mechanical load. The primary outcomes of creep behavior were studied using implicit visco-plastic analysis for the solder. Equivalent of Creep Strain (ECS), and Total Equivalent of Creep Strain (TECS) history showed different results for the various parameter sets of the same solder. Since SAC305 is one of the most widely used lead-free soldering materials, for simulation purposes, researchers must rely on the material properties obtained from experimental results. In this study, a more general view is presented regarding SAC305 visco-plastic properties.