An impingement-based cooler has distributed coolant outlets to place the cooling liquid in direct contact with the chip. The cooler sprays the liquid perpendicular to the chip surface to ensure all the liquid on the chip surface has the same temperature and to reduce the contact time between coolant and chip. Most current impingement coolers are silicon-based, which makes them expensive, or feature nozzle diameters or processes that are not compatible with the chip packaging process flow.
Imec’s new impingement chip cooler uses polymers to achieve a cost-effective fabrication and has nozzles of only 300µm, made by high-resolution stereolithography 3D printing. This allows customization of the nozzle pattern design to match the heat map and the fabrication of complex internal structures, and prints the structure in one part to reduce production cost and time.
The cooling efficiency of the new technique shows a temperature increase of less than 15°C per 100W/cm 2 for a coolant flow rate of 1 l/min and has a pressure drop as little as 0.3 bar. It outperforms benchmark conventional cooling solutions in which the thermal interface materials alone cause a 20-50°C temperature increase. imec’s cooling solution is also much smaller than existing solutions, matching the footprint of the chip package.