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

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.