MLHP: A High Heat Flux Localized Cooling Technology for Electronic Substrates

Abstract

A novel microscale device based on phase change technology is proposed for localized cooling of very high heat flux electronic substrates. Device physics and salient design features are elucidated and a numerical model is developed to predict device performance and optimize the design parameters. The Micro-columnated Loop Heat Pipe (MLHP) consists of evaporator and condenser sections connected by liquid and vapor microchannels, all fabricated on a silicon wafer using MEMS microfabrication techniques. A novel micro-columnated wick is designed to prevent wick dryout to enhance reliability. The MLHP operates using capillary pumping thus requiring no external power and provides enhanced localized cooling capabilities by interfacing directly with a heat producing chip. Recent studies on microscale fluid flow and heat transfer physics in microchannels are implemented in a numerical model to predict the performance of the MLHP. A detailed design optimization study is performed to maximize the device heat flux carrying capacity, which at 1400 W/cm2 is a considerable improvent on all of the existing high heat flux cooling technologies.