Micromachined Jet Arrays for Liquid Impingement Cooling of VLSI Chips

Abstract

Two-phase cooling of VLSI chips with microjet heat sinks promises a new, effective heat removal method. Microjet arrays can achieve improved temperature uniformity in the presence of chip hotspots. This paper describes the development and assesses the performance of micromachined single and multi-jet arrays with orifice diameters less than 100 m. The devices were tested in a confined geometry with a dedicated heater test chip, as well as in an open geometry with a standard 1 cm 2 Intel test chip. In the confined geometry, a 76 m diameter four-jet array at a flow rate of 8 ml/min removed over 90 W/cm 2 . Experimental comparisons of microjet and microchannel performance show that microjets have improved thermal uniformity, offer a significantly more stable two-phase region, and do not exhibit superheating. These advantages suggest that microjet arrays are the preferred micro heat sinks for effective device cooling.