Reliability test and analysis for vibration-induced solder joint failure of PBGA assembly

In order to understand the vibration characteristic of plastic BGA solder joints, the test vehicles with daisy chain were designed, vibration reliability test platform and real-time monitoring platform were developed, a series of vibration test including sweep vibration at different levels and random vibration were conducted, and the comparative study for experiments and simulation results was carried out. And the effect of void and pad type on the maximum vibration stress of solder joint was studied. The results showed the relation between deformation of test vehicle and input accelerator represented nonlinear characteristic. The failure of solder joint was occurred firstly in the PBGA which was located on the center of board due to the maximum deformation. The solder joint failure presented the character of solder joint crack, and the crack was initiated at the soldering interface close to solder joint outmost on BGA side and propagated to the internal of solder joint. It can be known that the soldering interface close to SMD pads on BGA side had higher stress concentration and poorer adhesive strength, NSMD solder pad is useful to raise the vibration reliability of solder joint, and maximum stress of solder joint have few sensitive for the changing of solder pad thickness. The phenomenon was validated in the cross-section results. The soldering voids were easy to induce the stress concentration around the voids.