Performance of a MEMS based micro capillary pumped loop for chip-level temperature control

Pettigrew, Kenneth; Kirshberg, Jeffrey; Yerkes, Kirk L.; Trebotich, David; Liepmann, Dorian

doi:10.1109/memsys.2001.906569

Cited by 27 publications

(23 citation statements)

References 3 publications

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“…Using aqueous or liquid-metal droplets to facilitate IC cooling is beneficial in that it has the ability to rapidly respond to changing cooling demands. Similar works can be found in [19][20][21][22].…”

Section: Ewod Applicationssupporting

confidence: 75%

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The Use of Impedance Spectroscopy in Characterizing Low Voltage Electrowetting-on-dielectric

Hu¹

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Being able to control fluid shape and flow using an external electric field alone without any mechanical parts, electrowetting-on-dielectric (EWOD) has drawn a lot of attention from researchers which leads to the the invention of many interesting applications. In the laboratory, EWOD characterization is generally conducted using direct optical observation of the droplet. While being a straight-forward method, optical techniques are laborious, slow, subject to optical distortions, and impractical in devices where the electrowetted droplet is a functional part of a larger system. In such cases, having an integrated means to interrogate the droplet configuration quickly and accurately would be highly desirable. As most EWOD experimental setups/devices have a metalinsulator-metal structure, it is possible to characterize the wetting process using electrical measurements. Prior e↵orts in characterizing EWOD electrically exhibit limitations in: 1) the dielectric layer used were relatively thick; 2) overly simplistic assumptions were made regarding the droplet shape. Because electrical characterization of EWOD is beneficial in many ways, we have investigated methods to expand its use and increase its flexibility so it could be applied to various kinds of experiments and applications. In this work, we first experimentally investigated the impedance of various EWOD configurations as a function of frequency, helping researchers to develop a framework for characterizing the impedance of an EWOD experiment using electrode properties and material parameters. Secondly, we developed methods to use electrical measurements in conjunction with known capillary bridge geometries to accurately determine unknown parameters in electrowetting (e.g., contact angle, liquid volume, interfacial tension, etc.). Lastly, we designed, built, and tested a capacitance measurement system capable of high-speed time-resolved measurements of electrowetting behavior.

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Section: Ewod Applicationssupporting

confidence: 75%

“…In Problem III, the initial zero bias contact angle ✓ 0 and the liquid/ambient surface tension are known and used for calculating the upper contact angle ✓ uj in (19). However, if one or both of these two parameters are unknown, they may still be found by the following approach.…”

Section: Problem IVmentioning

confidence: 99%

The Use of Impedance Spectroscopy in Characterizing Low Voltage Electrowetting-on-dielectric

Hu¹

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“…Some of the air-based MEMS devices include an array of microfabricated membranes actuated electromagnetically to produce air microjets for cooling of packaged ICs [2], an air impinging-jet heat exchanger [13], a micromachined microfin array heat sink to enhance hydrodynamic mixing by creating vortices to dissipate heat faster [3], and a micro capillary pumped loop where an evaporator, condenser, reservoir, and liquid lines are all integrated [8].…”

Section: Related Prior Workmentioning

confidence: 99%

Cooling of integrated circuits using droplet-based microfluidics

Pamula¹,

Chakrabarty²

2003

Proceedings of the 13th ACM Great Lakes Symposium on VLSI - GLSVLSI '03

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Decreasing feature sizes and increasing package densities are making thermal issues extremely important in IC design. Uneven thermal maps and hot spots in ICs cause physical stress and performance degradation. Many MEMS and microfluidics-based solutions were proposed in the past. We present a cooling method based on high-speed electrowetting manipulation of discrete submicroliter droplets under voltage control with volume flow rates in excess of 10 mL/min. We also propose a flow-rate feedback control where the hot areas get increased supply of droplets without the need for external sensors and electrothermocapillary control where hot areas attract droplets due to thermocapillarity and are returned to their reservoirs by electrowetting resulting in a self-contained and a self-regulated system.

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“…A few attempts at building working set-ups have been made, especially in the USA (Kirshberg et al 1999;Liepmann 2001;Pettigrew et al 2001;Meyer and Phinney 2003). Numerically, the micro-loops studied in the above articles can extract up to 4 W of heat with an evaporator surface area of 2 mm 2 and a liquid line length of 35 mm.…”

Section: Introductionmentioning

confidence: 99%

Miniaturised Capillary Pumped Loops: Design and Operating Limits

Serin

Lavieille

Miscevic

2009

Microgravity Sci. Technol.

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This paper has two main objectives: i) to propose some design changes compared to the ones available in the literature in order to improve the reliability of micro capillary pumped loop operating at steady state and ii) to demonstrate the existence of an optimum in the loop ability to extract and transport heat flux considering classical constraint of electronic devices. Numerical simulations allow the temperature profiles to be determined both in the fluid and in the substrate. Thanks to that, the heat conduction effect can be analysed. Finally, three operating limits of the system are highlighted. Consequently the heat loop performance presents a maximum according to the saturation temperature value of the working fluid.

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Performance of a MEMS based micro capillary pumped loop for chip-level temperature control

Cited by 27 publications

References 3 publications

The Use of Impedance Spectroscopy in Characterizing Low Voltage Electrowetting-on-dielectric

The Use of Impedance Spectroscopy in Characterizing Low Voltage Electrowetting-on-dielectric

Cooling of integrated circuits using droplet-based microfluidics

Miniaturised Capillary Pumped Loops: Design and Operating Limits

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