Solder joint crack propagation analysis of wafer-level chip scalepackage on printed circuit board assemblies

摘要

The solder-joint reliability of a low-cost wafer-level chip scalepackage (WLCSP) on printed circuit board (PCB) under thermal fatigue isstudied. The solder joints are subjected to thermal cycling and theircrack lengths at different thermal cycles are measured. Also, the stressintensity factors at the crack tip of different crack lengths in thecorner solder joint are determined by fracture mechanics with finiteelement method. Furthermore, an empirical equation for predicting thethermal-fatigue life of flip chip solder joints is proposed