High Power/Heat Flux Applications and Technologies

High power applications use heat spreaders to remove 50 to 500 Watts from 1cm x 1cm or 2.54cm x 2.54cm chips. High heat flux applications use heat spreaders to reduce heat fluxes of 100 to 1,000 W/cm²  by 10 to 100X. As shown in the figure (top right), a solid heat spreader is critical to these applications because the heat flux in the device level is too high to be manageable. Unfortunately, such a heat spreader is not effective even with a diamond substrate. As a result, the relatively high heat flux after spreading needs to be carried away by an expensive approach such as liquid cooling with impinging jets.  With Kelvin Thermal's TGP, we now have an opportunity to apply the extremely high evaporation heat transfer to aborb the high heat flux and spread the heat to a large area through vapor transport. Therefore, the expensive jet cooling is not required, and a simple liquid cooling or even air cooling scheme becomes possible.

As shown in the figure (bottom right), we have demonstrated a removal of heat fluxes up to 450 W/cm² for a 0.3cm x 0.3cm chip at 35 Watts. For a larger chip, e.g. 1cm x 1cm, we demonstrated a successful removal of 120 Watts/cm² heat flux in 2018. For the larger chip, it was very challenging to supply liquid water to the center of the chip/evaporator region. It is why the heat flux level is much lower than that for the 0.3cm x 0.3cm chip. Such evaporation heat tranfser performance is not unique. The major advantage of Kelvin Thermal's TGP is that we applied an IP-protected multilayer woven mesh to achieve such impressive heat flux removal performance. Even better, we improved the performance from 120 to 250 W/cm² in 2020, and we expect to improve it further to reach 500 W/cm² by 2021.

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