This study investigates the effects of the grain size of Cu on the bonding performance of Cu-to-Cu bonding. We prepare two Cu films with different grain sizes, fine-grained (FG) and coarse-grained (CG), and bond them using various bonding conditions (temperature and pressure). We next characterize the microstructure of the bonded samples using focused ion beam-scanning electron microscopy (FIB-SEM), unfolding a superior bonding performance for the FG samples: they exhibit active bonding interface migration at 150˚C while the CG samples do not display any noticeable interface migration at temperatures below 300˚C. Further microstructure analysis using electron backscattered diffraction (EBSD) helps us disclose significant differences in grain growth behavior: the FG sample displays abnormal grain growth of some (001) grains, indicative of strain-energy-driven grain growth, whereas the CG sample shows typical curvature-driven grain growth.
Sukkyung Kang
My research focuses on the phenomena arising from the physical contact between two engineered surfaces. The goal is to develop processing technologies that can create high-value, innovative products by precisely manipulating phenomena such as friction, wear, polishing, bonding, diffusion, adhesion, and deformation.