High heat flux cooling for silicon hybrid multichip packaging

Recent projections have suggested that heat fluxes will reach or exceed 100 W/cm² in future integrated circuit chips. Research on the application of both liquid-jet impingement with boiling and direct liquid immersion to the cooling of silicon substrates used in hybrid multichip packaging is described. The authors report the first data on cooling of silicon substrates using direct immersion cooling in Freon-12 and compare the results to those of liquid-jet impingement cooling of the same substrates. Heater fluxes of 200 W/cm² at a maximum temperature rise of 50 K have been achieved using 16 jets impinging with a nozzle velocity of 1 m/s. Immersion cooling experiments have reached heater fluxes of 100 W/cm² with a 45-K temperature rise. Results from two-dimensional numerical simulations of the test wafer are in excellent agreement with the immersion cooling data. These results indicate that both modes of cooling will be highly useful in the cooling and packaging technology for the next generation of high-performance computer systems