High Power Thermal Test Vehicle with 2-Phase Cooling for AI Datacenters, 5G RAN, and EDGE Compute Nodes

In this paper, we introduce the design and fabrication of a high-power thermal test vehicle (TTV) equipped with a two-phase cooling system, targeting improved thermal management in Multi-Chip Modules (MCMs) for AI datacenters, 5G RAN, and EDGE compute nodes. With the rise in device integration and component power densities, conventional cooling methods fall short, prompting the need for innovative approaches to achieve efficient heat dissipation. The TTV utilizes advanced heterogeneous integration techniques on a low-temperature co-fired ceramic (LTCC) substrate, designed to reliably dissipate over 1000 W of heat. This provides a robust platform for testing advanced two-phase cooling strategies to effectively remove heat from densely packed silicon dies, thus addressing the thermal challenges inherent in modern electronics.We elaborate on the fabrication of two variations of the TTV: the first comprising six X1 MCM modules, each measuring 25 mm × 38 mm, and the second a single X6 module measuring 76 mm × 76 mm, showcasing the robustness of the process. These TTVs are engineered to manage power dissipation of up to 1008 W, with logic chips experiencing background power densities of approximately 34 W/cm^2 and hotspots peaking at 400W/cm^2, while HBM stack chips exhibit a heat flux of 16 W/cm^2. The logic chips, measuring 20 mm x 20 mm, and the HBM stacks, measuring 10 mm x 10 mm, closely replicate the specifications of cutting-edge AI hardware.The importance of this work lies in its capacity to offer a scalable and dependable testing platform for advanced thermal management strategies in high-performance computing. By leveraging two-phase cooling, it paves the way toward more reliable and efficient computing infrastructures, effectively addressing the challenges posed by high power and heat flux in contemporary electronic devices.