MEMS-enabled thermal management of high-heat-flux devices EDIFICE: embedded droplet impingement for integrated cooling of electronics

This paper reports the development of embedded droplet impingement for integrated cooling of electronics (EDIFICE). The EDIFICE project seeks to develop an integrated droplet impingement cooling device for removing chip heat fluxes in the range 70-100 W/cm(2), employing latent heat of vaporization of dielectric fluids (50-100 mum droplets) to achieve these high heat removal rates. Micro-manufacturing and micro electro-mechanical systems (MEMS) will be discussed as enabling technologies for innovative cooling schemes recently proposed. A novel feature to enable adaptive on-demand cooling is MEMS sensing (on-chip temperature, remote IR temperature and ultrasonic dielectric film thickness) and MEMS actuation. EDIFICE will be integrated within the electronics package and fabricated using advanced micro-manufacturing technology (e.g., deep reactive ion etching (DRIE) and complementary metal-oxide semiconductor (CMOS) CMU-MEMS). The development of EDIFICE involves modeling, CFD simulations, and physical experimentation on test beds. In this study, numerical simulations are performed to investigate EDIFICE jet impingement cooling with a dielectric coolant and the influence of several parameters such as jet diameter, jet velocity, and latent heat effects. This paper also presents flow visualization of micro-jet break-up, induced by MEMS micro-nozzles of irregular shapes and flow swirling to generate droplets with desirable dispersion. To enhance liquid spreading on the impingement surface and to create a thin film for effective evaporation, MEMS micro-structured surfaces are fabricated. All of these components are made from silicon and enabled by integrated-MEMS process technologies. (C) 2001 Elsevier Science Inc. All rights reserved.