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.

With the rapid development of power electronics, power modules are required to achieve higher power density, wider operating temperature ranges, faster switching speed, and improved reliability. Large area sintering (LAS), due to its high electrical and thermal conductivity, has been widely recognized as a promising interconnection technology for power module packaging. Nevertheless, several challenges remain, including copper oxidation, package warpage, organic binder burnout and gas exhaust, and other processing-related issues. This article reviews recent research and patents on LAS technology, covering its background, classification, key challenges, and possible solutions. Based on the currently dominant process conditions and sintering materials, different LAS approaches are systematically summarized. Furthermore, three critical issues are highlighted, including organic burnout and excessive exhaust remaining, power module warpage, and copper oxidation control. For each challenge, the related reliability issues, current solutions, and future research directions are reviewed.