Global Digital Central Logo Frontiers in Heat and Mass Transfer (FHMT)

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Mohamed S El-Genk, Amir F Ali
Frontiers in Heat and Mass Transfer (FHMT) 3 - 043001 (2012)


Advanced spreaders for cooling a 10 x 10 mm underlying computer chip with a central hot spot (CHS) remove > 85 W of dissipated thermal power at junctions’ temperature < 100 oC. The spreaders comprise 1.6 - 3.2 mm thick Cu substrate and 80-mm thick micro-porous copper (MPC) surface cooled by saturation nucleate boiling of PF-5060 dielectric liquid. Investigated are the effects of varying the heat flux at the chip’s 1 and 4 mm2 CHS and the impedance of thermal interface material (TIM) between the Cu substrate and underlying chip. Results confirmed the effectiveness of the MPC spreaders for cooling the chip and mitigating the effect of CHSs. With a TIM impedance of 0.19 oC-cm2/W, the spreader with a 3.2 mm-thick Cu substrate removes 90.1 W and 87.85 W for the chip with 1 and 4 mm2 CHS and a heat flux ratio (HFR) at CHS of 6. The maximum chip surface temperature at the CHS is 90.16oC and 96.6oC and the spreader’s footprint area is 25.5 and 25.25 cm2, respectively. Decreasing the TIM impedance to 0.02oC-cm2/W decreases the chip’s maximum surface temperature to 73.4 and 76.1oC, but slightly changes the removed thermal power to 90.3 W and 86.24W, respectively.

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ISSN: 2151-8629