Thermal fatigue reliability enhancement of plastic ball grid array (PBGA) packages

Abstract

A combined design of experiment and numerical analysis approach is used to determine the effect of four design parameters on the thermal fatigue life of solder joints. The four parameters considered were: substrate thickness, array configuration, ball pitch, acid pad size. A full factorial experiment was designed which was conducted numerically. A validated life prediction model was then used to determine the fatigue lives for each combination. Up to a factor of five improvement in fatigue life is predicted when these parameters were changed from one level to another.