Experimental investigation of the embedded microchannel manifold cooling for power chips

Power chips with high power dissipation and high heat flux have caused serious thermal management problems. Traditional indirect cooling technologies could not satisfy the increasing heat dissipation requirements. The embedded cooling directly inside the chip is the hot spot of the current research, which bears greater cooling potential comparatively, due to the shortened heat transfer path and decreased thermal resistance. In this study, the thermal behaviors of the power chips were demonstrated using a thermal test chip (TTC), which was etched with microchannels on its substrate?s backside and bonded with a manifold which also fabricated with silicon wafer. The chip has normal thermal test function and embedded cooling function at the same time, and its size is 7 ? 7 ? 1.125 mm3. This paper mainly discussed the influence of width of microchannels and the number of manifold channels on the thermal and hydraulic performance of the embedded cooling structure in the single-phase regime. Compared with the conventional straight microchannel structure, the cooling coefficient of performance (COP) of the 8?-50(number of manifold distribution channels: 8, microchannel width: 50 ?m)structure is 3.38 times higher. It?s verified that the 8?-50 structure is capable of removing power dissipation of 300 W (heat flux: 1200 W/cm2) at a maximum junction temperature of 69.6 ? with pressure drop of less than90.8 kPa. This study is beneficial to promote the embedded cooling research, which could enable the further release of the power chips performance limited by the dissipated heat.

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Investigation of On-Chip Hot Spot Cooling Using Microchannel Heat Sink

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.455.466 ◽

2013 ◽

Vol 455 ◽

pp. 466-469

Author(s):

Yun Chuan Wu ◽

Shang Long Xu ◽

Chao Wang

Keyword(s):

Heat Flux ◽

Heat Sink ◽

Hot Spots ◽

Hot Spot ◽

High Heat ◽

High Heat Flux ◽

Microchannel Heat Sink ◽

Three Dimensional Model ◽

Spot Cooling ◽

On Chip

With the increase of performance demands, the nonuniformity of on-chip power dissipation becomes greater, causing localized high heat flux hot spots that can degrade the processor performance and reliability. In this paper, a three-dimensional model of the copper microchannel heat sink, with hot spot heating and background heating on the back, was developed and used for numerical simulation to predict the hot spot cooling performance. The hot spot is cooled by localized cross channels. The pressure drop, thermal resistance and effects of hot spot heat flux and fluid flow velocity on the cooling of on-chip hot spots, are investigated in detail.

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Thermo-Fluid-Stress-Deformation Analysis of Two-Layer Microchannels for Cooling Chips With Hot Spots

Journal of Electronic Packaging ◽

10.1115/1.4030005 ◽

2015 ◽

Vol 137 (3) ◽

Cited By ~ 4

Author(s):

Abas Abdoli ◽

George S. Dulikravich ◽

Genesis Vasquez ◽

Siavash Rastkar

Keyword(s):

Heat Flux ◽

Thermal Stresses ◽

Hot Spot ◽

Heat Removal ◽

High Heat ◽

Heat Transfer Analysis ◽

Deformation Analysis ◽

High Heat Flux ◽

Cooling Design ◽

Microchannel Cooling

Two-layer single phase flow microchannels were studied for cooling of electronic chips with a hot spot. A chip with 2.45 × 2.45 mm footprint and a hot spot of 0.5 × 0.5 mm in its center was studied in this research. Two different cases were simulated in which heat fluxes of 1500 W cm−2 and 2000 W cm−2 were applied at the hot spot. Heat flux of 1000 W cm−2 was applied on the rest of the chip. Each microchannel layer had 20 channels with an aspect ratio of 4:1. Direction of the second microchannel layer was rotated 90 deg with respect to the first layer. Fully three-dimensional (3D) conjugate heat transfer analysis was performed to study the heat removal capacity of the proposed two-layer microchannel cooling design for high heat flux chips. In the next step, a linear stress analysis was performed to investigate the effects of thermal stresses applied to the microchannel cooling design due to variations of temperature field. Results showed that two-layer microchannel configuration was capable of removing heat from high heat flux chips with a hot spot.

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A Mathematical Modeling Method for Capillary Limit of Micro Heat Pipe with Sintered Wick

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.175.335 ◽

2011 ◽

Vol 175 ◽

pp. 335-341

Author(s):

Xi Bing Li ◽

Chang Long Yang ◽

Gong Di Xu ◽

Wen Yuan ◽

Shi Gang Wang

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Heat Pipe ◽

Heat Dissipation ◽

High Heat ◽

Experimental Investigations ◽

High Heat Flux ◽

Micro Heat Pipe ◽

Copper Powders ◽

Capillary Limit

With heat flux increasing and cooling space decreasing in microelectronic and chemical products, micro heat pipe has become an ideal heat dissipation device in high heat-flux products. Through the analysis of its working principle, the factors that affect its heat transfer limits and the patterns in which copper powders are arrayed in circular cavity, this paper first established a mathematical model for the crucial factors in affecting heat transfer limits in a circular micro heat pipe with a sintered wick, i.e. a theoretical model for capillary limit, and then verified its validity through experimental investigations. The study lays a powerful theoretical foundation for designing and manufacturing circular micro heat pipes with sintered wicks.

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Design of Thermoelectric Modules for High Heat Flux Cooling

Journal of Electronic Packaging ◽

10.1115/1.4028118 ◽

2014 ◽

Vol 136 (4) ◽

Cited By ~ 4

Author(s):

Ram Ranjan ◽

Joseph E. Turney ◽

Charles E. Lents ◽

Virginia H. Faustino

Keyword(s):

Heat Flux ◽

Electrical Current ◽

High Heat ◽

Packing Fraction ◽

Heat Fluxes ◽

Coefficient Of Performance ◽

Shear Stresses ◽

High Heat Flux ◽

Thermoelectric Coolers ◽

Active Elements

Thermoelectric (TE) coolers work on the Seebeck effect, where an electrical current is used to drive a heat flux against a temperature gradient. They have applications for active cooling of electronic devices but have low coefficients of performance (COP < 1) at high heat fluxes (>10 W/cm2, dT = 15 K). While the active elements (TE material) in a TE cooling module lead to cooling, the nonactive elements, such as the electrical leads and headers, cause joule heating and decrease the coefficient of performance. A conventional module design uses purely horizontal leads and vertical active elements. In this work, we numerically investigate trapezoidal leads with angled active elements as a method to improve cooler performance in terms of lower parasitic resistance, higher packing fraction and higher reliability, for both supperlattice thin-film and bulk TE materials. For source and sink side temperatures of 30 °C and 45 °C, we show that, for a constant packing fraction, defined as the ratio of active element area to the couple base area, trapezoidal leads decrease electrical losses but also increase thermal resistance. We also demonstrate that trapezoidal leads can be used to increase the packing fraction to values greater than one, leading to a two times increase in heat pumping capacity. Structural analysis shows a significant reduction in both tensile and shear stresses in the TE modules with trapezoidal leads. Thus, the present work provides a pathway to engineer more reliable thermoelectric coolers (TECs) and improve their efficiency by >30% at a two times higher heat flux as compared to the state-of-the-art.

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Design of Practical Liquid Metal Cooling Device for Heat Dissipation of High Performance CPUs

Journal of Electronic Packaging ◽

10.1115/1.4002012 ◽

2010 ◽

Vol 132 (3) ◽

Cited By ~ 29

Author(s):

Yueguang Deng ◽

Jing Liu

Keyword(s):

Heat Flux ◽

Liquid Metal ◽

Thermal Resistance ◽

High Performance ◽

Heat Dissipation ◽

High Heat ◽

High Heat Flux ◽

Water Cooling ◽

Cooling Device ◽

Liquid Metal Cooling

Broad societal needs have focused attention on technologies that can effectively dissipate huge amount of heat from high power density electronic devices. Liquid metal cooling, which has been proposed in recent years, is fast emerging as a novel and promising solution to meet the requirements of high heat flux optoelectronic devices. In this paper, a design and implementation of a practical liquid metal cooling device for heat dissipation of high performance CPUs was demonstrated. GaInSn alloy with the melting point around 10°C was adopted as the coolant and a tower structure was implemented so that the lowest coolant amount was used. In order to better understand the design procedure and cooling capability, several crucial design principles and related fundamental theories were demonstrated and discussed. In the experimental study, two typical prototypes have been fabricated to evaluate the cooling performance of this liquid metal cooling device. The compared results with typical water cooling and commercially available heat pipes show that the present device could achieve excellent cooling capability. The thermal resistance could be as low as 0.13°C/W, which is competitive with most of the latest advanced CPU cooling devices in the market. Although the cost (about 70 dollars) is still relatively high, it could be significantly reduced to less than 30 dollars with the optimization of flow channel. Considering its advantages of low thermal resistance, capability to cope with extremely high heat flux, stability, durability, and energy saving characteristic when compared with heat pipe and water cooling, this liquid metal cooling device is quite practical for future application.

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Design of High Packing Fraction Thermoelectric Modules for High Heat Flux Cooling

Volume 2: Thermal Management; Data Centers and Energy Efficient Electronic Systems ◽

10.1115/ipack2013-73073 ◽

2013 ◽

Cited By ~ 1

Author(s):

Ram Ranjan ◽

Joseph E. Turney ◽

Chuck E. Lents

Keyword(s):

Heat Flux ◽

Electrical Current ◽

High Heat ◽

Packing Fraction ◽

Heat Fluxes ◽

Coefficient Of Performance ◽

High Heat Flux ◽

Thermoelectric Coolers ◽

Module Design ◽

Active Elements

Thermoelectric (TE) coolers work on the Seebeck effect, where an electrical current is used to drive a heat flux against a temperature gradient. They have applications for active cooling of electronic devices but have low coefficients of performance (COP<1) at high heat fluxes (>10 W/cm2). While the active elements (thermoelectric material) in a TE cooling module lead to cooling, the non-active elements, such as the electrical leads and headers, cause joule heating and decrease the coefficient of performance. A conventional module design uses purely horizontal leads and vertical active elements. In this work, we numerically investigate trapezoidal leads with angled active elements as a method to improve cooler performance for both supperlattice thin film and bulk thermoelectric materials. We show that, for a constant packing fraction, defined as the ratio of active element area to the couple base area, trapezoidal leads decrease electrical losses but also increase thermal resistance. We also demonstrate that trapezoidal leads can be used to increase the packing fraction to values greater than one, leading to a two times increase in heat pumping capacity. Thus the present work provides a pathway to improve the efficiency of the state-of-the-art thermoelectric coolers by > 30% at a two times higher heat flux.

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Thermal Management of On-Chip Hot Spot

ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer, Volume 3 ◽

10.1115/mnhmt2009-18548 ◽

2009 ◽

Cited By ~ 4

Author(s):

Avram Bar-Cohen ◽

Peng Wang

Keyword(s):

Heat Flux ◽

Thermal Management ◽

Hot Spot ◽

High Heat ◽

High Heat Flux ◽

Switching Speed ◽

Primary Driver ◽

Management Approaches ◽

On Chip ◽

Physical Phenomena

The rapid emergence of nanoelectronics, with the consequent rise in transistor density and switching speed, has led to a steep increase in microprocessor chip heat flux and growing concern over the emergence of on-chip “hot spots”. The application of on-chip high heat flux cooling techniques is today a primary driver for innovation in the electronics industry. In this paper, the physical phenomena underpinning the most promising on-chip thermal management approaches for hot spot remediation, along with basic modeling equations and typical results are described. Attention is devoted to thermoelectric microcoolers — using mini-contcat enhancement and in-plane thermoelectric currents, orthotropic TIM’s/heat spreaders, and phase-change microgap coolers.

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Numerical Simulation of a Thermosyphon Radiator Used in Electronic Devices

Journal of Robotics and Mechanical Engineering ◽

10.53996/2770-4122.jrme.1000106 ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Liang Ding ◽

Wei Wang ◽

Bingrui Li ◽

Yong Shuai ◽

Bingxi Li

Keyword(s):

Heat Flux ◽

Numerical Model ◽

Thermal Resistance ◽

Wall Temperature ◽

Thermal Load ◽

Heat Dissipation ◽

Electronic Devices ◽

High Heat ◽

High Heat Flux ◽

Load Conditions

The heat dissipation of electronic devices is an important issue. The thermosyphon radiators have high heat dissipation performance, so they are gradually widely used in electronic devices. In this study, a numerical model of the thermosyphon is established. It is observed that simulated temperatures agree well with experimental data in the literature with a relative error no more than 4%. After the numerical model is validated, it is used in the simulation of the thermosyphon radiator. The wall temperature of the condensing section under different thermal load conditions is compared, and the thermal resistance of the condensing section is analyzed. The results show that with the increase of heating and condensing heat flux, the wall temperature fluctuation of the condensing section increases, but very small just about 5K, 6K, 7K, and 9K, respectively. The thermal resistance of the condensing section decreases, indicating that the thermosyphon radiator has a better performance under high heat flux conditions.

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