Thermal conductance across bonded SiO <i>x</i> –SiO <i>x</i> interfaces in hybrid bonding process

Hybrid bonding is a pivotal technology for enabling three-dimensional integrated circuits (3D-ICs). Among the foremost challenges facing 3D-IC implementation is thermal management, where a deep understanding of heat conduction across bonded interfaces is essential for addressing heat dissipation and reliability issues. Nevertheless, the thermal conductance of bonded dielectric–dielectric interfaces remains poorly understood. In this study, we employ the low-temperature bonding technique integral to hybrid bonding to fabricate SiOx–SiOx interfaces and investigate their thermal boundary conductance (TBC) using time-domain thermoreflectance. Structural characterizations show high-quality bonded interfaces. By fitting the data with an equivalent multilayer thermal model, we establish a lower-limit TBC of 150 MW m−2 K−1 for the SiOx–SiOx interfaces, which corresponds to a thermal resistance lower than that of a 9.2-nm-thick dielectric layer. These findings offer valuable insights into thermal transport in hybrid-bonded structures and provide critical guidance for the thermal design of advanced packaging solutions.