Parameter sensitivity study of cure-dependent underfill properties on flip chip failures

Abstract

A parameter sensitivity study directed to the effects of cure-dependent underfill properties on Flip Chip's die cracking and solder fatigue lifetime is presented. The cure dependent behavior is modeled with a modified version of an earlier published cure dependent viscoelastic model. In the modified model the cure-dependent "equilibrium" shear- and bulk-moduli are modified compared to the original description. The developed FEM models for die cracking and solder fatigue are integrated with a sequential type of Design of Experiments (DOE). Two response surface models (RSM's), one for die cracking, the other for solder fatigue lifetime, are established using the obtained FEM simulation results. The developed RSM's are employed to conduct a parameter sensitivity study.