Thermal Fatigue Analysis of Solder Balls in Chip-last Fan-out Chip Package

As the demand for high performance computing continues to grow, FOCoS with high heterogeneous integration has become a trend in the packaging industry. Heterogeneous integration refers to the integration of multiple small chips into higher-level components and is one of the advantages that distinguishes it from other packages. It is also the reason that the location of dangerous solder balls under this package system is not clear. Therefore, in this paper, the thermal fatigue analysis of solder balls with three different solder materials under temperature cyclic loading is performed by Workbench to discover the locations where critical solder joints occur, analyze the fatigue mechanism of the solder joints and predict the lifetime of the whole package body based on the σ-N curve. Based on the simulation results, the material coefficients that have the greatest impact on the fatigue life are determined, which is a guide to improve the thermal fatigue life of solder joints in FOCoS packages.