A high-efficiency three-dimensionally (3-D) shaped polymer multi-jet impingement cooler based on cost-efficient fabrication techniques is introduced for the cooling of high-power applications. State-of-the-art highly efficient multi-jet cooling solutions rely on expensive Si or ceramic fabrication techniques, while low-cost cooling solutions have been proposed for less performant single-jet impingement. In this paper, we present the concept, modeling, design, fabrication, experimental characterization, and benchmarking with literature data of a multi-jet impingement based liquid cooling solution, fabricated using low-cost polymer fabrication techniques, targeted to directly cool the backside of high-power devices. For the modeling study, unit cell model and full system level models are used to study the nozzle array scaling trends and thermal and fluidic jet-to-jet interactions. Furthermore, design guidelines for high-power electronics cooling are provided, including geometry selections, material selection, and fabrication techniques. Based on the design guidelines and cooling concept, this paper demonstrates a 3-D-shaped polymer impingement cooler with a 4 × 4 nozzle array, showing a very good thermal performance with low required pumping power. The multi-jet cooler can achieve heat transfer coefficients up to 6.25 × 10 ⁴ W/m ² ·K with a pump power as low as 0.3 W. The benchmarking study confirms furthermore that multi-jet cooling is more efficient than single-jet cooling and that direct cooling on the backside of the semiconductor device is more efficient than cooling the substrate or base plate.

This article presents the design, fabrication, experimental characterization, and modeling analysis of the chip-level hotspot targeted liquid impingement jet cooling for high-power electronics. The hotspot targeted jet impingement cooling concept is successfully demonstrated with a chip-level jet impingement cooler with a 1-mm nozzle pitch and 300-μm nozzle diameter fabricated using high-resolution stereolithography (additive manufacturing). The computational fluid dynamics (CFD) modeling and experimental analysis show that the improved hotspot targeted cooler design with fully open outlets can reduce the on-chip temperature difference by 70% compared with the full array cooler at the same pumping power of 0.03 W. The local heat transfer coefficient can achieve 15 × 10 ⁴ W/m ² K with a local flow rate per nozzle of 40 mL/min, requiring a pump power of 0.6 W. The benchmarking study proves that the hotspot targeted cooling is much more energy-efficient than uniform array cooling, with lower temperature difference and lower pump power.

In this article, we design, demonstrate, and characterize a 3-D printed package-level polymer jet impingement cooling solution on a 23×23 mm ² thermal test chip. The experimental hardware results for a nozzle pitch of 2 mm show that, with 1-kW power dissipation, at a coolant (deionized (DI) water) flow rate of 3 liters per minute (LPM), the measured average chip temperature increase is ~65 °C with a cooler pressure drop of 0.15 bar between the inlet and outlet connections. It is also shown that bare die cooling without lid [and thermal interface material (TIM)] shows better cooling performance than the lidded package. Second, an advanced 3-D printed manifold with an additional flow redistribution structure is demonstrated. The experimental results show that the improved design achieves a better chip temperature uniformity compared to the reference design, showing a reduction of the chip temperature gradient with a factor of 4 and 2.3 for a flow rate of 0.5 and 3 LPM, respectively, while no significant impact on the cooler pressure drop was measured. The numerical modeling studies predict an additional 15.4% thermal performance improvement, by reducing the nozzle pitch from 2 to 1 mm, for a flow rate of 3 LPM.