Increasing miniaturization has led a significant increase in the current densities seen in flip-chip solder joints. This has made the study of failure in solder joints by void propagation due to electromigration and stress migration more important. In this study, we develop a phase field model for the motion of voids through a flip chip solder interconnect. We derive equations of motion for the void accounting for energetic contributions from the active factors of surface energy, stress and electric potential, taking into account both surface diffusion and transfer of the material through the bulk of the material. We describe the implementation of this model using finite elements, coupled with a commercial finite element solver to solve for the fields driving the void motion.
