Study of the effect of hybrid bonding interface defects on the copper diffusion mechanism

Three-dimensional integration technology based on hybrid bonding is an effective approach to achieving high-performance. However, misalignments arising during the bonding process can introduce defects, thereby increasing the risk of copper contamination. In this study, a cross-scale joint simulation model is developed to investigate the copper diffusion mechanism at the Cu/barrier layer/SiO2 interface, with the aim of elucidating the impact of bonding mismatches on interfacial diffusion behavior. A finite element model is established to analyze the effect of misalignment on stress distribution and types of defects. A molecular dynamics model (MD) of diffusion at the hybrid bonding interface is developed to explore the potential mechanisms of copper diffusion in silica. The MD model also investigates the effects of barrier layer and defects. The simulation results are validated through micro-characterization experiments, which are employed to confirm the types of interfacial defects and to observe copper diffusion behavior in the presence of these defects.