Development of Scalable Silicon Heat Spreader for High Power Electronic Devices

A silicon heat spreader, called hexcell, is presented to develop thin, strong, interconnected, and scalable heat transfer devices for high power electronics cooling. Several key technical aspects, reflected characteristics of fabrication, thermomechanical, hermetic sealing, and heat transfer on wick structures, have been performed to underlie the system integration. The hexcell prototypes are developed through microelectromechanical system photolithography and dry-etch processes, associated with eutectic bonding to form a sealed silicon chamber. Hexcells are structurally optimized to minimize the stress, expanding the maximum operating pressure and temperature ranges. As a result, the developed hexcells can survive 0.32 MPa pressure difference and are able to sustain an operating temperature over 135°C. Experimental results of both helium and vapor leakage tests indicate that eutectic bonding with limited bonding surface area may not provide hermetic sealing. Vacuum sealing is achieved by introducing epoxy to fill the leak pine-holes on the bonding interface. The developed hexcell wick exhibits good heat and mass transport performance, reaching a maximum 300 W/cm2 cooling capacity with 35°C superheat as demonstrated with a prototype of a 2×2 mm2 heating area.

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Capillary Pumped Loop Heat Spreader for Electronics Cooling

10.1115/imece2001/htd-24405 ◽

2001 ◽

Author(s):

Jaewon Chung ◽

Costas P. Grigoropoulos ◽

Ralph Greif

Keyword(s):

Electronics Cooling ◽

Cooling Capacity ◽

Impinging Jets ◽

Heat Sinks ◽

Manufacturing Cost ◽

Air Cooling ◽

Capillary Pumped Loop ◽

Heat Spreader ◽

Vertical Orientation ◽

Thermoelectric Coolers

Abstract As cooling requirements for electronic devices, e.g. computer processor units, power modules, etc. increase beyond the capabilities of air-cooling, interest has moved to several alternatives such as thermoelectric coolers, impinging jets and heat exchangers with phase change. Included among these, the capillary pumped loop is a very competitive cooling device, because of its performance reliability, no power requirements and low manufacturing cost. In this paper, a heat spreader employing capillary pumped loop principles was made of aluminum and copper and tested. The copper CPL heat spreader with heat sinks and fans on the condenser (86mm thick, 60mm wide, 181mm long) has demonstrated a cooling capacity of 640W at atmospheric pressure in the vertical orientation and maintains a difference between TIHE (temperature of the interface between heater and evaporator) and TAMB (ambient temperature) lower than 100°C.

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Thermal Performance of Microchannels With Dimples for Electronics Cooling

ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2013-22198 ◽

2013 ◽

Cited By ~ 1

Author(s):

Hui Lu ◽

Liang Gong ◽

Minghai Xu

Keyword(s):

Heat Transfer ◽

Laminar Flow ◽

Integrated Circuits ◽

Heat Sink ◽

Electronics Cooling ◽

Cooling Capacity ◽

Constant Heat Flux ◽

Microchannel Heat Sink ◽

Transfer Enhancement ◽

Different Types

The thermal management of integrated circuits becomes more and more serious since the density of transistors grows gradually. Recently, a new cooling method is dedicated to develop microchannel heat sink with high integrated and high cooling efficiency. In view of above purpose, the heat transfer enhancement and pressure drop reduction in microchannel with dimples are investigated in this paper. A single module of 1mm×1mm×20mm with a microchannel was employed, which hydraulic diameter and aspect ratio are 500 μm and 2:1 respectively. For replacing the running integrated circuits, a constant heat flux of 1W/mm2 was arranged on the bottom of the heat sink. Six different types of microchannels with dimples were designed and numerically studied under the condition of laminar flow. The results show that dimple could enhance heat transfer and decrease flow resistance under the condition of laminar flow. Compared with traditional microchannel heat sink, dimple-microchannel heat sink has stronger cooling capacity, could be an attractive choice for cooling of future microelectronics.

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Oscillatory Streaming Flow Based Mini/Microheat Pipe Technology

Journal of Heat Transfer ◽

10.1115/1.4000443 ◽

2010 ◽

Vol 132 (5) ◽

Cited By ~ 2

Author(s):

Z. Zhang ◽

C. Liu ◽

A. Fadl ◽

D. M. L. Meyer ◽

M. Krafczyk ◽

...

Keyword(s):

Heat Transfer ◽

System Integration ◽

Cost Effective ◽

Fluid Distribution ◽

Scaling Analysis ◽

Transfer Coefficients ◽

Heat Spreader ◽

Channel Networks ◽

Mean Velocity ◽

Streaming Flow

The sustained drive for faster and smaller micro-electronic devices has led to a considerable increase in power density. The ability to effectively pump and enhance heat transfer in mini-/microchannels is of immense technological importance. Using oscillatory flow to enhance the convective heat transfer coefficients in micro-/minichannels is one of many new concepts and methodologies that have been proposed. In this paper, a novel and simple concept is presented on oscillating streaming flow based mini/microheat pipe or heat spreader technology. Phenomena of the flow streaming can be found in zero-mean velocity oscillating flows in many channel geometries. Although there is no net mass flow (zero-mean velocity) passing through the channel, discrepancy in the velocity profiles between the forward and backward flows causes fluid particles near the walls to drift toward one end while particles near the centerline drift to the other end. This unique characteristic of flow streaming could be used for various applications. Some of the advantages include enhanced heat/mass transfer, pumpless fluid propulsion, multichannel fluid distribution, easy system integration, and cost-effective operation. Preliminary work has been conducted on scaling analysis, computer simulations, and visualization experiments of fluid streaming, propulsion, and multichannel distribution by flow oscillation in minitapered channels and channel networks. Results show that streaming flow has the potential to be used as a cost-effective and reliable heat pipe and/or as a heat spreader technique when fluid thermal conductivity is low.

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Theoretical Post-Dryout Heat Transfer Model

International Journal of Computational Physics Series ◽

10.29167/a1i1p142-150 ◽

2018 ◽

Vol 1 (1) ◽

pp. 142-150

Author(s):

Murat Tunc ◽

Ayse Nur Esen ◽

Doruk Sen ◽

Ahmet Karakas

Keyword(s):

Heat Transfer ◽

Droplet Diameter ◽

Heat Transfer Model ◽

Transfer Model ◽

Operating Pressure ◽

Vertical Pipe ◽

Two Phase ◽

Experimental Values ◽

Reactor Operating ◽

Coolant System

A theoretical post-dryout heat transfer model is developed for two-phase dispersed flow, one-dimensional vertical pipe in a post-CHF regime. Because of the presence of average droplet diameter lower bound in a two-phase sparse flow. Droplet diameter is also calculated. Obtained results are compared with experimental values. Experimental data is used two-phase flow steam-water in VVER-1200, reactor coolant system, reactor operating pressure is 16.2 MPa. On heater rod surface, dryout was detected as a result of jumping increase of the heater rod surface temperature. Results obtained display lower droplet dimensions than the experimentally obtained values.

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Heat transfer characteristic modelling and the effect of operating conditions on re-cooled cycle for a scramjet

The Aeronautical Journal ◽

10.1017/s0001924000005479 ◽

2011 ◽

Vol 115 (1164) ◽

pp. 83-90 ◽

Cited By ~ 1

Author(s):

W. Bao ◽

J. Qin ◽

W. X. Zhou

Keyword(s):

Heat Transfer ◽

Heat Sink ◽

Transfer Characteristic ◽

Cooling Capacity ◽

Sensitivity Study ◽

Performance Model ◽

Operating Conditions ◽

Inlet Temperature ◽

Fuel Flow ◽

Temperature And Pressure

Abstract A re-cooled cycle has been proposed for a regeneratively cooled scramjet to reduce the hydrogen fuel flow for cooling. Upon the completion of the first cooling, fuel can be used for secondary cooling by transferring the enthalpy from fuel to work. Fuel heat sink (cooling capacity) is thus repeatedly used and fuel heat sink is indirectly increased. Instead of carrying excess fuel for cooling or seeking for any new coolant, the cooling fuel flow is reduced, and fuel onboard is adequate to satisfy the cooling requirement for the whole hypersonic vehicle. A performance model considering flow and heat transfer is build. A model sensitivity study of inlet temperature and pressure reveals that, for given exterior heating condition and cooling panel size, fuel heat sink can be obviously increased at moderate inlet temperature and pressure. Simultaneously the low-temperature heat transfer deterioration and Mach number constrains can also be avoided.

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Investigation of heat transfer from circular cylinders in high power 10 kHz and 20 kHz acoustic resonant fields

International Journal of Thermal Sciences ◽

10.1016/s1290-0729(00)00270-2 ◽

2000 ◽

Vol 39 (8) ◽

pp. 771-779 ◽

Cited By ~ 10

Author(s):

Volker Uhlenwinkel ◽

Rongxiang Meng ◽

Klaus Bauckhage

Keyword(s):

Heat Transfer ◽

High Power ◽

Circular Cylinders

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Accurate numerical modeling of convective heat transfer coefficient for a high power PLA-core toroidal electromagnetic coupler subject to cooling

International Journal of Thermal Sciences ◽

10.1016/j.ijthermalsci.2021.107125 ◽

2021 ◽

Vol 170 ◽

pp. 107125

Author(s):

F.Z. Boudara ◽

H. Bouzekri ◽

Y. Benhammadi ◽

P.-H. Cocquet ◽

M. Rivaletto ◽

...

Keyword(s):

Heat Transfer ◽

Numerical Modeling ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Convective Heat Transfer ◽

Convective Heat ◽

High Power ◽

Convective Heat Transfer Coefficient

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Transient Heat Transfer in Microscale Porous Materials Heated by Microsecond Laser Pulse of High Power Density

Heat Transfer, Volume 7 ◽

10.1115/imece2002-32115 ◽

2002 ◽

Author(s):

Fangming Jiang ◽

Dengying Liu ◽

Jim S.-J. Chen ◽

Richard S. Cohen

Keyword(s):

Heat Transfer ◽

Heat Conduction ◽

Laser Pulse ◽

Power Density ◽

High Power ◽

Hyperbolic Model ◽

Transient Temperature ◽

Hyperbolic Heat Conduction ◽

High Power Density ◽

High Heat Transfer

A novel experimental method was developed to measure the rapid transient temperature variations (heating rate > 107 K/s) of porous samples heated by high surface heat fluxes. With a thin film (0.1 μm thick) resistance thermometer of platinum as the temperature sensor and a super-high speed digital oscilloscope (up to 100 MHz) as the data recorder, rapid transient temperature variation in a porous material heated by a microsecond laser pulse of high power density is measured. Experimental results indicate that for high heat transfer cases (q′ > 109 W/m2) with short durations (5 – 20 μs) of heating, non-Fourier heat conduction behaviors appear. The non-Fourier hyperbolic heat conduction model and the traditional Fourier parabolic model are employed to simulate this thermal case respectively and the FDM is used to perform the numerical analysis. The hyperbolic model predicts thermal wave behavior in qualitative agreement with the experimental data.

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