Numerical simulations of the influence of thermal cycling parameters on the mechanical response of SAC305 interconnects

Abstract Electronic assemblies are continuously subjected to cyclic thermal loadings during operation, which can lead to fatigue failures in solder interconnections. A typical thermal cycle is characterized by high and low dwell temperatures, dwell durations, and ramp rates. Although the effects of these cycling parameters have been discussed in the literature, a comprehensive understanding remains elusive. This article aims to investigate the impact of various thermal cycling parameters, including cycling temperature range, high dwell temperature, and dwell duration, on the thermomechanical behavior of SAC305 through extensive finite element simulations. Four thermal cycling profiles, 0/100, −40/125, −55/125, and −15/150°C, are analyzed. Additionally, three dwell durations (10, 15, and 30 min) are assessed while maintaining a constant ramp rate of 10°C/min across all cycling configurations. This study thoroughly evaluates the thermomechanical response of SAC305 interconnections in terms of stress, inelastic strains, and inelastic strain energy density. The results indicate that the mechanical response, damage accumulation, and the anticipated fatigue performance of SAC305 interconnections are significantly influenced by the cycling parameters. Notably, longer dwell durations exacerbate damage to solder interconnections, thereby reducing the number of cycles to failure. Furthermore, while accumulated strain energy may not fully capture the effects of cycling temperature range and maximum dwell temperature on solder damage, these factors are effectively reflected in the computations of inelastic strains. Consequently, study recommends the development of fatigue life estimation models that prioritize equivalent inelastic strain as a damage parameter and incorporate the effects of cycling temperature range, maximum dwell temperature, and dwell durations to enhance lifetime predictions and model generalization. The results and recommendations of the present study can be very insightful in designing reliable experiments and empirical models for the estimation of fatigue life performance of SAC305 interconnects.