Oxidation Mechanism of Copper Layer on AMB Substrate in Power Modules

Abstract

Serving as a significant attachment component, Active Metal Brazed (AMB) substrates are prone to oxidation during storage and processing. The copper surface oxidation of AMB substrates seriously affects the reliability of high-power modules. The formation of Cu2O/CuO oxide layer on the surface degrades interfacial qualities in subsequent packaging processes, including sintering, wire-bonding, and transfer-molding. To investigate the mechanism behind, this paper constructs a physically grounded multiscale oxidation framework that explicitly bridges molecular dynamics with reactive force field (ReaxFF-MD) and mesoscale continuum modeling. For ReaxFF-MD simulations, it aims to resolve oxygen adsorption, dissociation, diffusion behavior, and Cu-O network formation on the Cu(100), Cu(110), and Cu(111) surfaces at temperatures of 300 K and 600 K. Diffusion coefficients and interface reaction kinetic parameters are then quantitatively extracted from MD simulations and transferred as a bridge in reaction-diffusion continuum model with flux damping governed by a characteristic structural thickness. The results demonstrate that the early oxidation process of the copper surface is modulated by structural evolution and orientation anisotropy. The proposed multiscale framework provides a physical mechanism basis for understanding the early oxidation mechanism of copper and its impact on the reliability of AMB packaging.