Cooling future system-on-chips with diamond inter-tiers

• Published in: Cell reports physical science Vol. 4; no. 12; p. 101686
• Main Authors: Malakoutian, Mohamadali, Kasperovich, Anna, Rich, Dennis, Woo, Kelly, Perez, Christopher, Soman, Rohith, Saraswat, Devansh, Kim, Jeong-kyu, Noshin, Maliha, Chen, Michelle, Vaziri, Sam, Bao, Xinyu, Shih, Che Chi, Woon, Wei-Yen, Asheghi, Mehdi, Goodson, Kenneth E., Liao, Szuya Sandy, Mitra, Subhasish, Chowdhury, Srabanti
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 20.12.2023
• Subjects: 2D-3D SoC; BEoL compatible; diamond; diamond inter-tiers; in-plane thermal conductivity; thermal management; 2D-3D SoC; diamond; diamond inter-tiers; thermal management; BEoL compatible; in-plane thermal conductivity
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2023.101686

Heat spreading is critical in reducing the overall junction temperature of monolithic system-on-chips (SoCs) and high-heat-flux radio frequency (RF) applications. Bulk diamond has the highest thermal conductivity (TC) in nature, but its TC degrades due to the presence of smaller and highly columnar grains. Diamond thin films can be used as the back-end-of-line (BEOL) dielectrics and thermal vias for effective heat spreading if high-quality isotropic diamond growth processes are developed. In this study, we grow large-grain thin-film diamonds (0.3–25 μm) with isotropic TC (300–1,800 W/m/K). This is achieved by controlling the lateral growth and terminating smaller grains at the nucleation stage without physically damaging the substrate. The enhancement of TC is achieved by lowering grain boundary density and graphite at the grains. Thermal modeling indicates that incorporating isotropic thin diamond reduces the temperature in a realistic flip chip and a monolithic 3D deep neural net accelerator by 20% and 50%, respectively. [Display omitted] •Thin-film diamonds with isotropic thermal conductivities•Thermal conductivities equal to 10× thicker conventional diamonds•Enhanced heat dissipation for system on chips, boosting reliability•Reduced temperature of 3D deep neural net accelerators by >50 Diamond-based heat spreaders can dissipate heat away from the semiconductor devices and reduce the need for energy-intensive cooling solutions such as lossy fans or sophisticated liquid-cooling systems. Malakoutian et al. develop high thermally conductive diamond thin films that enhance cooling efficiency from the hotspot to the heat sink.