Dynamic Response of Interconnects in Board-Level Packaging Structure at Extremely High Strain Rates

To more accurately characterize the dynamic behavior during impact, the dynamic response of SAC305 lead-free solder and epoxy molding compound (EMC) under high strain rates was investigated. An improved Johnson-Cook constitutive model was employed to describe the constitutive behavior of SAC305 solder. The improved Johnson-Cook constitutive model characterizes the transition effect of strain rate by incorporating a parabolic function into the original constitutive framework. Given the significant rate dependence of EMC under high strain rates, a nonlinear thermoviscoelastic ZWT constitutive model was utilized to elucidate the complex deformation mechanisms. Based on the proposed high strain rate constitutive models, the integration of multiple constitutive models was achieved for the mechanical response evaluation of the complete ball grid array (BGA) packaging structure model during the impact process.