Effects of solder joint shape on joint reliability in SMT

A numerical model was built up to predict the thermal fatigue lifetime of properties of SnPb joints in SMT by FEM. The thermal fatigue tests were carried out to test the numerical model. The results show that the during thermal fatigue test most of solder joint failure of pad 1 occurs from 1 440 to 1 680 cycles and the thermal fatigue lifetime of pad 1 is less than that of pad 2, it can be concluded that the predicted lifetime by FEM has a good agreement with the experimental result. Moreover, the numerical model is used to study the effects of solder joint shape on the thermal fatigue lifetime of the joints in SMT. The results can be used in lead-free solders in fixed conditions.