Heterogeneous Integration of Diamond-on-Chip-on-Glass Interposer for Efficient Thermal Management

Thermal management poses a critical challenge in the design of modern electronic packages. This letter presents a diamond-on-chip-on-glass interposer (DoCoG) technology that incorporates polycrystalline diamond heat-spreader substrates known for their exceptional thermal conductivity. These diamonds are directly bonded to the back-side of silicon chips on a glass interposer, resulting in markedly enhanced cooling performance. The junction-to-ambient thermal resistance dropped by 28.5% due to the integration of diamond. The creation of such multi-stacked DoCoG integration and efficient cooling necessitates a diamond/chip connection that combines a minimal bonding thermal budget, high working temperature, and low thermal boundary resistance. To address this challenge, the study proposes a low-temperature bonding technique through nanolayer Cu/Au recrystallization. The effects of bonding voids on overall cooling performance were investigated. These results represent significant progress toward universal approaches for the viable integration of high-performance coolers into electronic packages, potentially enabling applications that are currently constrained by thermal limitations in heterogeneous integrations.