Prediction of Statistical Distribution of Solder Joint Fatigue Lifetime Using Hybrid Probabilistic Approach

We propose a novel hybrid approach to examine uncertain sources that cause variations in solder joint lifetimes and to predict statistical distributions of solder joint lifetimes under actual operating conditions. The uncertainty in input variables of a life prediction model is propagated to the output by an approximate integration method. The variations in the output are statistically compared to experimentally-measured lifetimes. A set of input variables that minimize the discrepancy between predicted and experimental results is obtained through the optimization technique. The proposed approach is implemented for chip resistor assemblies, and the fatigue life of solder joints under the actual operating conditions is predicted after calibration.