Finite element method and experimental study on life prediction of lead-free BGA solder joints using an energy-based approach

This paper investigates the reliability of Ball Grid Array (BGA) package with different sizes and numbers of Sn3.0Ag0.5Cu solder balls from both experimental and simulation perspectives. The fatigue life of three different sizes of BGA packaged samples was obtained by conducting temperature cycling tests and simultaneously recording the resistance changes of the specimens. The characteristic life of the three types of samples was determined using the number of thermal cycles corresponding to 63.2% probability of failure in the two-parameter Weibull distribution. In order to achieve an optimal balance between the accuracy and efficiency of the simulation based on the finite element method (FEM), the submodel method is used to model the three types of samples and calculate the key variables of the life prediction model. The effect of mesh density on equivalent creep strain (CEEQ) and creep dissipated energy results was investigated. Based on the mesh-independence results, creep dissipated energy was used as a prediction parameter to obtain the Akay fatigue life prediction model under optimal mesh density. The model’s prediction accuracy is reasonably good, as validated by simulation and experimental data.