ABSTRACT
Solder joint thermal fatigue is a major mechanism of electronic products failure. Previous studies had proposed several physics-of-failure models for thermal fatigue life prediction based on stress, strain, or energy. However, few models considered fatigue crack propagation. From that point of view, this paper presented a novel fatigue crack propagation model for ball grid array package solder joint thermal fatigue life prediction. Due to the difficulty of crack length measurement, experiment was conducted to explore the relationship of fatigue crack propagation and daisy chains resistances growth, where the daisy chains were created by solder joint network. Furthermore, the finite element simulation method was used to extend this model for solder joints with different dimensions and materials and the final form of the fatigue crack propagation model was obtained.
