Chip integrated micro cooling system for high heat flux electronic cooling applications

Rapid development in VLSI Technology anticipates an urgent need for new micro cooling strategies for high heat flux electronic chips. This paper presents a novel high efficiency micropump/evaporator, based on electrohydrodynamic (EHD) forces, high heat flux electronic sensors. The device incorporates a MEMS-based active micro-evaporative surface and temperature sensors into a single package that can be directly attached to the heat source. The pump is designed to supply and maintain an ultra-thin liquid film on a 10 x 15 mm evaporative surface, which was a quartz or sapphire wafer with an array of EHD electrodes having gaps varying between 10 and 100 gm. A pumping pressure of up to 300 Pa and a cooling capacity of 25 W/cm2 were obtained at electric field strength of 4 V/mum using a 3M electronic coolant (HFE-7100) as the working fluid. The EHD power consumption in this case was only 2.5 mW for the highest heat flux. Electrical field simulations were performed using FemLab-2D software to understand the effects of electrode geometry on the electric field and on the fluid pumping effect. This work is part of an ongoing effort to develop a complete self-controlled two-phase micro cooling system for cooling single and multiple electronic components.