Physical Design of 3D FPGAs Embedded with Micro-channel-based Fluidic Cooling

Through Silicon Via (TSV) based 3D integration technology is a promising technology to increase the performance of FPGAs by achieving shorter global wire-length and higher logic density. However, 3D FPGAs also suffer from severe thermal problems due to the increase in power density and thermal resistance. Moreover, past work has shown that leakage power can account for 40\% of the total power at current technology nodes and leakage power increases non-linearly with temperature. This intensifies the thermal problem in 3D FPGAs and more aggressive cooling methods such as micro-channel based fluidic cooling are required to fully exploit their benefits. The interaction between micro-channel heat sink design and the performance of a 3D FPGA is very complicated and a comprehensive approach is required to identify the optimal design of 3D FPGAs subject to thermo-electrical constraints. In this work, we propose an analysis framework for 3D FPGAs embedded with micro-channel-based fluidic cooling to study the impact of channel density on cooling and performance. According to our simulation results, we provide guidelines for designing 3D FPGAs embedded with micro-channel cooling and identify the optimal design for each benchmark. Compared to naive 3D FPGA designs which use fixed thermal heat sink, the optimal design identified using our framework can improve the operating frequency and energy efficiency by up to 80.3% and 124.0%.