Effect of Strain-Enhanced Microstructural Coarsening on Thermal Fatigue Deformation of BGA Semiconductor Package Solder Joint

Abstract

The rate constants of the strain-induced particle growth equation were obtained from low-cycle fatigue tests. A creep constitutive equation incorporating the strain-induced particle growth equation was then implemented in a general-purpose FEM solver, and thermal fatigue analysis of solder joints in BGA semiconductor packages was performed. Thermal diffusion and strain-induced particle growth reduced the creep strength and increased inelastic strain energy range ΔW_in, the driving force for thermal fatigue failure. However, under the thermal fatigue conditions of this study, the contribution of strain-induced growth to particle growth was small, and thermal diffusion particle growth dominated the increase in ΔW_in of BGA solder joints during the ongoing thermal fatigue cycle.