Structural characterization and bonding energy analysis for plasma-activated bonding of SiCN films: A reactive molecular dynamics study

Abstract: Plasma-activated bonding of SiCN films offers high bonding strength at the hybrid-bonding interface, thereby enhancing mechanical reliability. Although experimental studies have shown that the interfacial bonding properties of SiCN films vary with SiCN composition and plasma treatment parameters, a clear correlation between these parameters and the resulting bonding properties has not yet been established. This study presents an atomistic investigation of SiCN-SiCN plasma-activated bonding with controlled SiCN composition and plasma fluence, which performs O2 plasma surface activation, surface hydroxylation, direct bonding, post-bonding annealing, and debonding using reactive molecular dynamics. The structural characterization of the plasma-activated SiCN surface, including density of various covalent bonds and surface roughness, exhibits composition- and plasma fluence-dependent chemical and morphological modification. Bonding energy evaluated from atomic traction-separation responses in cohesive zone volume elements (CZVE) during debonding simulations shows a positive correlation with the interfacial Si-O-Si density. Since the interfacial Si-O-Si density reflects the combined effects of these chemical and morphological modifications, the dependence of bonding energy on composition and plasma fluence is successfully elucidated by the structural characterization. These results establish an atomic-level material-process-property relationship and offer practical guidance for optimizing SiCN composition and plasma treatment parameters for SiCN-SiCN plasma-activated bonding.