Ultra-thin spray cooling shows promise for high-power AI chips
A 3.5-mm-thick spray cooling device dissipates more than 600 W from a silicon-based thermal test chip, showing potential for thermal management in high-power-density electronics
image: The ultra-thin spray cooling system integrates a 3.5-mm-thick micro-nozzle array with a silicon-based thermal test chip. The image shows the device structure and assembly, together with experimental measurements demonstrating its cooling and heat transfer performance at different heat fluxes and flow rates. The compact system achieved a peak heat transfer coefficient of 9.03 W/(cm²·K) and successfully dissipated more than 600 W of heat, highlighting a potential solution for thermal management in space-constrained, high-power-density electronics such as AI and high-performance computing chips.
Credit: © Hua Chen,Wen-Long Cheng,et al. 2026.
As artificial intelligence and high-performance computing continue to drive chip power densities higher, removing large amounts of heat within increasingly limited space has become a major challenge. Spray cooling offers strong heat-transfer capabilities, but conventional systems can be difficult to integrate into compact chip architectures.
Researchers at the University of Science and Technology of China have developed an ultra-thin spray cooling heat sink only 3.5 mm thick and experimentally demonstrated its performance on a silicon-based thermal test chip. The study was published in Thermo-X.
The researchers integrated a four-nozzle spray array within a compact 17 × 17 × 3.5 mm³ module. Combined with silicon-based microfabrication, the design enables near-field spray cooling with a nozzle-to-chip distance of only 2 mm. A silicon-based thermal test chip was fabricated to evaluate the cooling performance, with deionized water used as the working fluid.
At a flow rate of 5.5 mL/s, the system handled a heat flux of 680.6 W/cm². Under this condition, the central temperature of the test chip reached 115.8 °C. Under this condition, the central temperature of the test chip reached 115.8 °C. The system achieved a heat-transfer coefficient of 9.03 W/(cm²·K) and a minimum thermal resistance of 0.11 cm²·K/W.
The experiments also revealed strong localized heat-transfer behavior. At this heat load, the temperature difference between the center and edge of the heating zone reached 68.2 °C. The researchers further observed an approximately 24 °C temperature difference between the heat-generating surface and the heat-exchange interface, which they attributed primarily to the thermal conductivity of the single-crystal silicon substrate.
These findings suggest that further improvements could be achieved by using thinner chip architectures or substrate materials with higher thermal conductivity, such as silicon carbide.
The study also identified a “premature boiling” phenomenon under lower-flow and high-heat-flux conditions. The authors attributed this behavior to localized pressure reduction in the recirculation zone, which can trigger nucleate boiling under subcooled conditions.
By integrating an ultra-thin spray array with a silicon-based thermal test chip, the study demonstrates the potential of spray cooling for high-heat-flux thermal management under severe space constraints. The approach could provide a pathway toward compact cooling solutions for future high-power-density electronics, including high-performance computing and artificial intelligence chips.