Solder joint lifetime evaluation of WLP and cause investigation

To examine dispersion of the packaging reliability of WLP, we grouped Weibull distribution of the temperature cycle test lifetime every tendency. And we examined in detail the cross section of the solder which is the typical sample of each group. As a result, it became clear that the lifetime and solder resist opening diameter had correlation. Furthermore, it became clear that the destruction modes which I received due to solder-resist opening diameter were different. Then, by using a crack developing simulation technology, each destruction mode of solder could be confirmed and we proposed the guideline which controls dispersion of lifetime.