Hot spot mitigation using single-phase microchannel cooling for microprocessors

(2017) Liquid cooling of non-uniform heat flux of a chip circuit by subchannels. Applied Thermal Engineering, 115, pp. 558-574. (doi:10.1016Engineering, 115, pp. 558-574. (doi:10. /j.applthermaleng.2016 This is the author's final accepted version.There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it. AbstractExperimental and numerical analyses have been carried out to study the effect of using subchannels in a liquid cooled heat sink for minimising the effect of hotspots generated on a chip or circuit. Two heat sinks -with and without subchannels -were fabricated in order to investigate this effect. The first device was manufactured with normal parallel channels while the second was designed to extract more heat by dividing the main channels above the hotspot into two subchannels. The inlet and outlet manifolds were designed with two inlet ports to minimise any potential mal-distribution of mass flow rate through the channels. Three thermocouples were attached to the bottom surface of the inlet manifold and another three attached to the outlet manifold to record surface temperature. Five different mass flow rates were generated under gravity by changing water container height. The results show that adding subchannels improves the uniformity of temperature distribution and reduces the maximum temperature. Moreover, at the same pressure head 79cm the thermal resistance is reduced 20% whereas the pumping power is increased by 11%.

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“…7. The water level was altered by changing the position of the container and steps [1][2][3][4][5][6][7] repeated for the next mass flow rate.…”

Section: Experimental Methodology and Stepsmentioning

confidence: 99%

“…Chauhan et al [7] numerically investigated the effect of rearranging the chip layout. They studied three cases: first by placing high heat flux components at the inlets of the microchannels, second the flow was reversed and third counter flow was imposed between two adjacent microchannels.…”

Section: Introductionmentioning

confidence: 99%

Liquid cooling of non-uniform heat flux of a chip circuit by subchannels

Al-Waaly

Paul

Dobson

2017

Applied Thermal Engineering

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“…Extensive simulation and experimental investigations were also performed on superlattice μTEC which is attributed to a relatively higher value of TEC figure of merit, faster response time, and reduced joule heating [10]- [16]. An alternative approach to minimize the hotspot temperature by optimizing microprocessor floor planning was proposed in [17]. The functional modules on the chip are rearranged to capitalize the high heat transfer coefficient of a developing region in the microchannel heat sink while not more than one high heat flux component is allowed on the same sets of channels.…”

Section: Introductionmentioning

confidence: 99%

Hotspot Mitigating With Obliquely Finned Microchannel Heat Sink—An Experimental Study

Lee

Chou

2013

IEEE Trans. Compon., Packag. Manufact. Technol.

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Sectional oblique fins are employed, in contrast to continuous fins, in order to modulate the flow in a microchannel heat sink. The breakage of continuous fin into oblique sections leads to reinitialization of boundary layers and generation of secondary flows that significantly enhance the cooling performance of the heat sink. In addition, an oblique finned microchannel heat sink has the flexibility to tailor local heat transfer performance by varying its oblique fin pitch. Clusters of oblique fins at higher density can be created in order to promote a greater degree of boundary layer redevelopment and secondary flow generation to provide more effective cooling at the high heat-flux region. Thus, the variation of oblique fin pitch can be exploited for hotspot mitigation. Experimental studies of a silicon chip with two hotspot scenarios show that the temperature hike and the temperature difference for the enhanced microchannel heat sink with variable pitch are reduced by as much as 17.1°C and 15.4°C, respectively. As a result, temperature distribution across the silicon chip is more uniform. In addition, the associated pressure drop penalty is much smaller than the achieved heat transfer enhancement, rendering it as an effective hotspot mitigating strategy for the single-phase microchannel heat sink.Index Terms-Enhanced microchannel, hotspot cooling, oblique fins, variable pitch.

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“…Although this is a promising theoretical work, integration with ICs is not considered in their study. Chauhan et al [13] utilized single-phase flow in the microchannel coupled with the electrical design (by selecting an optimum floor plan) for mitigation of hot spots in an Intel Pentium IV microprocessor. The numerical simulations verified the effectiveness of their computational model design.…”

Section: Introductionmentioning

confidence: 99%

Reliable MOSFET operation using two-phase microfluidics in the presence of high heat flux transients

Singh¹,

Agrawal²,

Duttagupta³

2011

J. Micromech. Microeng.

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Randomly generated heat flux transients affect the reliability of advanced integrated circuits and can induce severe nonlinearity in the device response, resulting in the degradation of a gate dielectric in metal oxide field effect transistors (MOSFETs). The effect of high heat flux transients on MOSFET operation and mitigation, using single-phase and two-phase on-chip microfluidics, is reported in this paper. A prototype comprising monolithically integrated MOSFETs, resistance temperature detector (RTD) arrays, simulated transient source (microheaters) and microfluidic networks was developed. The application of a 10 s transient (153 W cm −2 ) led to the degradation of subthreshold swing (S) from 120 to 240 mV/decade. However, in the presence of water flow, effective mitigation of S (up to 75%) is observed. The rate of mitigation is higher at lower flow rates because of the higher heat-transfer efficiency for two-phase flow. Thus, an appropriate selection of flow parameters can lead to optimized cooling. Additionally, we propose a strategy to localize the transient heat sources based on the temperature profiles generated using an on-chip, distributed RTD sensor array. The proposed methodology can be applied in practical integrated circuits for localization and characterization of heat sources leading to modifications in the circuit design or process integration steps.

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Hot spot mitigation using single-phase microchannel cooling for microprocessors

Cited by 11 publications

References 10 publications

Liquid cooling of non-uniform heat flux of a chip circuit by subchannels

Liquid cooling of non-uniform heat flux of a chip circuit by subchannels

Hotspot Mitigating With Obliquely Finned Microchannel Heat Sink—An Experimental Study

Reliable MOSFET operation using two-phase microfluidics in the presence of high heat flux transients

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