Hot spot analysis in integrated circuit substrates by laser mirage effect

Perpiñà, X.; Jordà, X.; Vellvehı́, M.; Altet, Josep

doi:10.1063/1.3581038

Cited by 11 publications

(5 citation statements)

References 17 publications

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“…square exit geometry (Technologies for Research, Model: RT1 × 1) was used to generate a laminar and near adiabatic methane/air flame with sufficient optical access. This burner has been widely used as a test bed for laser diagnostic techniques [14][15][16][17][18][19][20]. The Hencken burner produces a unique, nearly adiabatic flame that is lifted from the burner surface since the fuel and oxidizer streams are separated until the exit of the burner.…”

Section: Methodsmentioning

confidence: 99%

Flame temperature measurements by radar resonance-enhanced multiphoton ionization of molecular oxygen

Sawyer

Adams

2012

Appl. Opt.

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Here we report nonintrusive local rotational temperature measurements of molecular oxygen, based on coherent microwave scattering (radar) from resonance-enhanced multiphoton ionization (REMPI) in room air and hydrogen/air flames. Analyses of the rotational line strengths of the two-photon molecular oxygen C(3)Π(v=2)←X(3)Σ(v'=0) transition have been used to determine the hyperfine rotational state distribution of the ground X(3)Σ(v'=0) state. Rotationally resolved 2+1 REMPI spectra of the molecular oxygen C(3)Π(v=2)←X(3)Σ(v'=0) transition at different temperatures were obtained experimentally by radar REMPI. Rotational temperatures have been determined from the resulting Boltzmann plots. The measurements in general had an accuracy of ~±60 K in the hydrogen/air flames at various equivalence ratios. Discussions about the decreased accuracy for the temperature measurement at elevated temperatures have been presented.

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Section: Methodsmentioning

confidence: 99%

Flame temperature measurements by radar resonance-enhanced multiphoton ionization of molecular oxygen

Sawyer

Adams

2012

Appl. Opt.

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“…cooling, on the other hand, is the major bottleneck for proper functioning of devices due to the formation of local hot spots with large on-chip temperature gradients [5,6].…”

Section: Nano-grooved Heat Pipesmentioning

confidence: 99%

“…It should be stated that, system-level thermal management is not the critical issue due to the availability of capable conventional cooling methods [4]. Chip-level cooling, on the other hand, is the major bottleneck for proper functioning of devices due to the formation of local hot spots with large on-chip temperature gradients [5,6].…”

Section: Introductionmentioning

confidence: 99%

A first look at the performance of nano-grooved heat pipes

Akkuş

Nguyen

Celebi

et al. 2019

International Journal of Heat and Mass Transfer

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Passive thermal spreaders utilizing liquid/vapor phase-change mechanism such as heat pipes, have been widely used in the macro-scale thermal management of electronic devices for many years. Micro-fabrication techniques enabled the fabrication micro-scale grooved heat pipes on semiconductors. Recent advances in fabrication techniques, on the other hand, enabled producing nano-andångström-scale capillaries and cavities, which renders the manufacturing of nanoscale heat pipes possible. In the present study, we have simulated nanoscale heat pipes composed of nano-grooves using molecular dynamics and evaluated their performance based on different operating parameters such as the filling ratio and heat load. Moreover, evaluation of size effect on the thermal performance is made by comparing proportionally scaled heat pipes. Simulation results reveal that efficient operation of nano-grooved heat pipes depend not only on the proper selections of filling ratio and heat load, but also on the geometrical parameters such as cross sectional dimensions and aspect ratio of the groove. The modeling strategy used in this study opens an opportunity for computational experimentation of nanoscale heat pipes. Nano-Grooved Heat PipesAkkus et al.cooling, on the other hand, is the major bottleneck for proper functioning of devices due to the formation of local hot spots with large on-chip temperature gradients [5,6].Thermal scientists have long been seeking efficient techniques to cool HHF devices. Singlephase cooling methods are impractical due to the high temperature difference and pumping needs [7]. Phase-change methods are desirable addressing their advantage in high latent heat of evaporation, which enables removal of high amount of heat with small temperature difference. Passive thermal spreaders utilizing liquid/vapor phase-change mechanism such as vapor chambers and heat pipes, are widely used in electronic cooling. Closed loop circulation of the working fluid is provided by the capillary pumping in liquid phase and density gradient in the vapor phase. While the vapor chambers have excellent hot spot removal ability by transporting the localized heat from a source to a large heat rejection surface, heat pipes function as superconductors to remove the waste heat away from the source.The first heat pipe was using wire mesh wick structure to pump the condensate to the evaporator section [8]. Then a single sealed non-circular micro-channel, whose sharp-angled corners work as liquid arteries, was proposed as micro heat pipes [9]. To increase the heat carrying capacity of a heat pipe, the number of liquid arteries should be maximized. Consequently, grooved heat pipes, which utilize multiple grooves machined on the inner wall of the base metal as the wick structures, have emerged and been widely studied in the literature due to the relative ease of their precise manufacturing and developing numerical solutions to estimate their performance [10,11,12,13,14,15,16,17]. Moreover, micro-electro-mechanical systems (MEMS) based micro-fabricat...

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“…To cover all such needs, off-chip single-shot imaging of nonelectrical observables (e.g., temperature or strain) is very promising [17], [18], [19], [20], as non-invasive testability of all internal nodes is assured while the RF-IC is under regular operation [21]. Thanks to the use combined of an RF block frequency-modulated driving and a mixer-like approach, electrical information is down converted from a higher to a lower frequency observable measured by following lock-in procedures (heterodyne technique) [20], [22], [23].…”

Section: Introductionmentioning

confidence: 99%

Output Power and Gain Monitoring in RF CMOS Class A Power Amplifiers by Thermal Imaging

Perpiñà

Reverter

León

et al. 2019

IEEE Trans. Instrum. Meas.

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 Abstract-The viability of using off-chip single-shot imaging techniques for local thermal testing in integrated Radio Frequency (RF) power amplifiers (PA's) is analyzed. With this approach, the frequency response of the output power and power gain of a Class A RF PA is measured, also deriving information about the intrinsic operation of its transistors. To carry out this case study, the PA is heterodynally driven, and its electrical behavior is down converted into a lower frequency thermal field acquirable with an InfraRed Lock-In Thermography (IR-LIT) system. After discussing the theory, the feasibility of the proposed approach is demonstrated and assessed with thermal sensors monolithically integrated in the PA. As crucial advantages to RF-testing, this local approach is noninvasive and demands less complex instrumentation than the mainstream commercially available solutions.

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Hot spot analysis in integrated circuit substrates by laser mirage effect

Cited by 11 publications

References 17 publications

Flame temperature measurements by radar resonance-enhanced multiphoton ionization of molecular oxygen

Flame temperature measurements by radar resonance-enhanced multiphoton ionization of molecular oxygen

A first look at the performance of nano-grooved heat pipes

Output Power and Gain Monitoring in RF CMOS Class A Power Amplifiers by Thermal Imaging

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