Thermal effects on droplet transport in digital microfluidics with applications to chip cooling

Thermal management has emerged as a critical issue in the design of integrated circuits (ICs). As feature sizes decrease and package densities increase, current package-level cooling techniques will soon become inadequate. While a number of MEMS-based cooling solutions have been proposed to address cooling at the IC level, many are not equipped to address the problem of real-time active and "smart" cooling, where hotter thermal regions (i.e., hot areas) are detected and subsequently cooled at an increased rate. We describe an alternative cooling method, on a platform we call "digital microfluidics", where nanoliter-sized discrete liquid droplets immersed in oil are manipulated. Cooling droplets are actuated independently in user-defined patterns over an array of electrodes by electrowetting, eliminating the need for external pumps. This paper presents the effects of temperature-dependent system parameters on droplet transport in this digital