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 enables high interfacial bonding strength, which is essential for the mechanical reliability of hybrid bonding technologies. While experimental studies have shown that the interfacial bonding properties of SiCN films depend on both film composition and plasma treatment conditions, the underlying atomistic correlations have not yet been established. In this work, we present an atomistic investigation of SiCN-SiCN plasma-activated bonding using reactive molecular dynamics simulations, focusing on the effects of SiCN composition and plasma fluence. The simulation model includes O2 plasma surface activation, surface hydroxylation, direct bonding, post-bonding annealing, and interfacial debonding. Structural analysis of plasma-activated SiCN surfaces reveals composition- and plasma fluence-dependent chemical and morphological modifications, characterized by changes in specific covalent bond density and surface roughness. Bonding energy, evaluated from traction-separation responses during debonding simulations, exhibits a positive correlation with the density of interfacial Si-O-Si linkages. As the interfacial Si-O-Si density reflects the combined effects of chemical activation and surface morphology, the dependence of bonding energy on both composition and plasma fluence can be interpreted at the atomic scale. These findings establish an atomic-level material-process-property relationship and provide practical guidance for selecting SiCN composition and plasma treatment conditions to enhance plasma-activated SiCN-SiCN bonding.