Bonding strength characterization of eutectic-based WLP using molecular dynamics and wafer level shear testing

This paper investigated the bonding shear strength of eutectic-based wafer-level-packaging (WLP) for piezoresistive MEMS accelerometers. The bonding conditions were experimentally and analytically determined to realize higher shear strength without a diffusion of the solder material atoms to the adhesion layers: the energy dispersive X-ray (EDX) spectrometry and molecular dynamics (MD) simulations clarified the eutectic reaction of solder materials used in this research. Consequently, the bonding load of 9.8 kN and the temperature of 300 °C was found to be one of rational conditions because of a sufficient shear strength to endure the polishing process after the WLP and few diffusion of solder material atoms to the adhesion layer.