An acceleration model for lead-free (SAC) solder joint reliability under thermal cycling

The electronics industry has successfully transitioned from Sn/Pb to Pb free (LF) solder for computing and consumer electronics applications. However, there is no industry-wide standardized LF solder joint reliability model (neither empirical nor FEA-based) available for solder fatigue reliability assessment. A LF solder fatigue model has been proposed in this paper based on a 3-parameter modified Coffin-Manson approach. The proposed model showed best fit to the experimental data (17 pairs of temperature cycle test data) from different sources for multiple package types and sizes including various test conditions. The model fit to the experimental data was excellent and the error was less than 6%. This analysis showed that the LF acceleration factor (AF) model is not significantly different from the Sn/Pb model and proposed model provides best fit to experimental results.