Thermal management is becoming an increasingly important issue in integrated circuit (IC) design. The ability to cool ICs is quickly reaching a limit with today’s package-level solutions. While a number of novel cooling methods have been introduced, many of which are microfluidic approaches, these methods are unable to adaptively address the uneven thermal profiles and hot-spots generated in high performance ICs. In this paper, we present a droplet-based digital microfluidic cooling system for ICs that can adaptively cool hot-spots through real-time reprogrammable flow. This paper characterizes the effectiveness of microliter-sized droplets for cooling by determining the heat transfer coefficient of a droplet shuttling back and forth in an open system over a hot-spot at various speeds. Cooling is found to be significantly enhanced at higher flow rates of droplets. In order to further enhance cooling, the effect of varying droplet aspect ratio (width/height) in a confined system was also studied.

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