Reliability of Various Underfills on BGA package

BGA 패키지에서의 다양한 언더필의 신뢰성 평가

In this study, the interfacial reactions and electrical properties of the Sn-35(wt%)Pb-2(wt%)Ag/Cu BGA solder joints after the thermal shock test were investigated with three different kinds of the underfill used commercially. The microstructural evolutions of the solder joints were observed using a scanning electron microscopy (SEM) and the electrical resistance of the solder joints were evaluated with the numbers of thermal shock cycle using the four-prove method. The increase in the $Cu_{6}Sn_{5}$ IMC thickness led to the increase in the electrical resistance with increasing the numbers of the thermal shock cycle. The increase in the electrical resistance of the BGA packages with the underfill was smaller than that without the underfill. The silica contained underfill led to the higher electrical resistance.