Reliability analysis of ceramic quad flat package under thermal cycling loading conditions by 3-D finite element method

ANSYS software was used to calculate the stress/strain distribution of ceramic quad flat package under thermal cycling. The results indicate that the stress distribution in solder joints were not uniform, the interface between lead and the heel of corner solder joint was the weakest position where the stress was hardly concentrated, the cracks should occur firstly at this point and then propagate along the interface, there appeared significant creep deformation and stress relaxation feature in the SnPb₃₇ solders under thermal cycling. The lead parameters affect stress distribution and thermal fatigue life of SnPb₃₇ solder significantly, the influence of the AgCu₂₈ solder volume cannot be ignored, which could even lead to Al₂O₃ crack. The flat-lead structure could provide longer fatigue life of SnPb₃₇ solder. The research provides data support for the reliability of ceramic packages and possess favorable guidance meaning for the package design in electronic industry.