Micromachined Jets for Liquid Impingement Cooling of VLSI Chips

Abstract

Abstract-Two-phase microjet impingement cooling is a potential solution for removing heat from high-power VLSI chips. Arrays of microjets promise to achieve more uniform chip temperatures and very high heat transfer coefficients. This paper presents the design and fabrication of single-jets and multijet arrays with circular orifice diameters ranging from 40 to 76 m, as well as integrated heater and temperature sensor test devices. The performance of the microjet heat sinks is studied using the integrated heater device as well as an industry standard 1 cm 2 thermal test chip. For single-phase, the silicon temperature distribution data are consistent with a model accounting for silicon conduction and fluid advection using convection coefficients in the range from 0.072 to 4.4 W/cm 2 K. For two-phase, the experimental results show a heat removal of up to 90 W on a 1 cm 2 heated area using a four-jet array with 76 m diameter orifices at a flowrate of 8 ml/min with a temperature rise of 100 C. The data indicate convection coefficients are not significantly different from coefficients for pool boiling, which motivates future work on optimizing flowrates and flow regimes. These microjet heat sinks are intended for eventual integration into a closed-loop electroosmotically pumped cooling system.[1186]

Interaction of scaling trends in processor architecture and cooling

“…For example, phase-change cooling [28], spot cooling for local hot spots [29], and thermal-electric couple cooling [30]. However, available data and scalability of these cooling solutions are hard to find and predict.…”

Differentiating the roles of IR measurement and simulation for power and temperature-aware design

“…There has to be a circulation mechanism to repeat the phase-change process. Examples are heatpipes in most laptop computers; droplet impingement spot cooling on hot chip surface [5]; refrigeration in data centers; phase-change heat spreader to achieve more uniform temperature across the die [15], etc.…”

Heat transfer enhancement in a small pipe by spinodal decomposition of a low viscosity, liquid?liquid, strongly non-regular mixture

“…Despite extensive research, there remain significant problems in the implementation of this technology. In contrast, two-phase jet impingement techniques have been investigated to a much lesser extent, despite the theoretical promise of very high heat transfer coefficients with high heat dissipation capability via thin film evaporation [5]. The implementation has comparable challenges.…”