The effect of different build-up structures on solder joint fatigue life under thermo-mechanical cyclic loading condition

In this paper, a FEA-based simulation procedure was established to evaluate the effect of different build-up structures on solder joint fatigue life under thermo-mechanical cyclic loading condition. The proposed methodology can therefore be used to select dielectric materials and core materials in build-up printed wiring boards (PWB) so that a build-up PWB board with the optimized combination of dielectrics and core material may be able to be obtained. The fatigue life of solder joint that links electronic package components to build-up PWB boards was chosen as an objective function to assess the feature of build-up PWB boards with the combinations of different dielectrics and core materials. The inelastic strain energy density-based Coffin-Manson model and the damage expression were adopted for the solder joint reliability assessment. The thermo-mechanical reliability for two selected packages assembled on eight-layer build-up (PWB) boards with five combinations of different dielectrics and core materials was investigated in terms of the framework developed. Based on the FEA results, a build-up PWB board with the optimized combination of dielectrics and core material for the selected package assemblies under thermo-mechanical cyclic loading condition was provided.