Exploring thermal effects of advanced backside power delivery network beyond 3 nm node

Abstract

Backside Power Delivery Networks (BSPDNs) address scaling issues by relocating power, boosting efficiency and density. However, thermal effects pose challenges. In this work, a comprehensive thermal analysis of BSPDN is performed to elaborate the key modulation factors and possible optimization approaches, where the specific backside metal layers are constructed to investigate the impacts of operating conditions, via distribution and materials on thermal effects. To improve the simulation efficiency, the effective thermal conductivity is employed to simplify the Nanosheet (NSH) FET based front-end-of-line (FEOL) and other layers at the 3 nm technology node. Results show that non-uniform via distribution in BSPDN causes temperature fluctuations, but augmenting Backside Via counts effectively mitigates local peak temperature increases from higher power. For BSPDN, backside cooling solutions outperform frontside in efficiency, particularly at high via densities. Using high thermal conductivity inter-metal dielectric (IMD) materials significantly reduces global temperature rise and fluctuations from non-uniform vias in BSPDN, enhancing PDN design flexibility.