Stacked Silicon Microcoolers

Abstract

Traditional machining techniques limit the flow channel and fin wall dimensions of high thermal conductivity metallic cold plates. Even though the thermal conductivity of silicon is lower compared to copper or aluminum, silicon micromachining techniques allow smaller flow channel and fin wall dimensions to enhance the heat transfer. However, the silicon fin height is limited by the standard wafer thickness. In this study, we develop stacked silicon microcoolers to increase the fin heights. An analytical method is used to identify the optimal fin wall and flow channel dimensions. A method of fabricating the stacked silicon microcoolers is then described.Stacked silicon microcoolers of various flow channel and fin wall dimensions are fabricated and integrated into thermal test packages. Experimental results of thermal resistance and pressure, spanning a wide range of chip power and fluid flow rates, are presented. The results demonstrate the high-performance envelope of the stacked silicon microcoolers. Directions for further thermal performance enhancement are also identified.