The experimental and numerical investigation on shear behaviour of solder ball in a wafer level chip scale package

The shear test under high strain rate is becoming a popular approach to investigate the fracture behaviour of a thermally attached solder ball under different strain rates. However, despite a substantial number of experimental tests being conducted recently, only a few numerical simulation works have been published. The lack of high performance computational analysis methods applicable to the evaluation of such a complex material and mechanical behaviour in solder interconnection, has yielded questionable accuracy of the simulation based on experimental observation. In this study, the experimental results regarding effects of shear loading speed are illustrated, and then three-dimensional explicit finite element analysis is employed to study dynamic responses of solder joints under ball impact testing. Through a three-dimensional explicit element analysis incorporated with a cohesive model, fracturing and fragmentation mechanisms, transient fracturing of the solder joint subjected to high speed impact test is investigated.