Effects of microstructure on thermal fatigue life prediction of solder joints

In the present study, effects of microstructure on the fatigue life of solder joints under thermal cycling conditions are evaluated using the finite element method. A unified, viscoplastic constitutive model for solder joints of plastic ball grid array packages is employed to improve accuracy of reliability prediction. The constitutive model is then implemented into the commercial finite element analysis software, ABAQUS, to predict the thermo-mechanical behavior of solder balls in PBGA package subjected to thermal cycling. Damage parameters are obtained from the FEA results and are used to estimate the thermal fatigue life of solder balls. The Coffin-Manson equation is employed. The predicted thermal fatigue lives are discussed in detail.