Numerical analysis of spreaders with an enhancing nucleate boiling surface for immersion cooling of chips with central hot spots

Presented are the results of numerical thermal analysis of composite and plane cu spreaders for immersion cooling of an underlying 10 × 10 mm chip with a 1 × 1 mm or 2 × 2 mm CHS. The composite spreaders are comprised of a 1.6 - 3.2 mm thick cu substrate and an 80-μm thick MPC surface. The analysis varied the heat flux at CHS from 2 - 6 times the chip´s surface average outside the hot spot. Saturation nucleate boiling of PF-5060 dielectric liquid cools the surface of the spreader. Results demonstrated the effectiveness of the composite spreaders for mitigating the effect of the CHS by decreasing the chip maximum surface temperature and increasing the thermal power removed. Increasing the area and heat flux of CHS and decreasing the thickness of the cu substrate decrease the thermal power removed and the spreader footprint area. However, they increase the total thermal resistance of the spreader and the chip maximum surface temperature.