A Closed Loop Submerged Jet Impingement Cooling System in Low Temperature Cofired Ceramic Substrates

A low temperature cofired ceramic (LTCC) substrate was fabricated with internal channels to allow for submerged jet impingement cooling on the backside of a simulated electronic device. Fugitive inserts and optimized lamination processes were used to fabricate internal X-Y channels with 500 micron widths and Zaxis channels of 170 micron diameter were fabricated in the substrate. The channels distributed coolant (water) to the Z-axis channels to form jets up to the backside of the active device. Reservoirs under the device captured the spent coolant, thus, forming a closed path coolant system. Single, four and nine jet configurations were tested with flow rates up to 45 mL/min at power dissipations up to 60 Watts on a 1 cm² device. The system was shown to reduce system thermal resistance from internally cooled substrates with high performance thermal via arrays by 50%, and also increased total heat flux capacity of the system. Compared to natural convection only, the jet impingement system was shown to reduce thermal resistance by two orders of magnitude and an estimated increase in heat flux capacity increase of 25times