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In this research work, an innovative method for measurement of thermal conductivity of a small volume of liquids, microsphere, and the single cancer cell is demonstrated using a micro-pipette thermal sensor (MPTS). The method is based on laser point heating thermometry (LPHT) and transient heat transfer. When a single pulse of a laser beam heats the sensor tip which is in contact with the surrounding liquids or microsphere/cells, the temperature change in the sensor is reliant on the thermal properties of the surrounding sample. We developed a model for numerical analysis of the temperature change using the finite element method (FEM) in COMSOL. Then we used MATLAB to fit the simulation result with experiment data by multi-parameter fitting technique to determine the thermal conductivity. To verify the accuracy in the measurement of the thermal conductivity by the MPTS method, a 10µl sample of de-ionized (DI) water, 50%, and 70% propylene glycol solution were measured with deviation less than 2% from reported data. Also, to demonstrate that the method can be employed to measure microparticles and a single spherical cell, we measured the thermal conductivity of poly-ethylene microspheres with a deviation of less than 1% from published data. We estimated the thermal conductivity of two types of cell culture growth media for the first time and determined the thermal conductivity of cancerous Jurkat Clone E6-1 to be 0.538 W/m.K ± 2%. Using the sensor of 1-2μm tip size, we demonstrated the MPTS technique as a highly accurate technique for determining the thermal conductivity of microfluidic samples, microparticles, biological fluids, and a non-invasive method for measuring the thermal conductivity of single cancer cell. This MPTS technique can be beneficial in developing a diagnosis method for the detection of cancer at an early stage. We also compared three effective thermal conductivity models for determining the weight percentage of Jurkat cell, considering water and protein as the major constituents. We discovered that a combination of Maxwell-Euken and effective medium theory model provides the closest approximation to published data and, therefore, recommend for the prediction of the cell composition.

ON-CHIP THERMAL SENSING IN DEEP SUB-MICRON CMOS August 2007 BASAB DATTA B.S., G.G.S. INDRAPRASTHA UNIVERSITY, NEW DELHI M.S.E.C.E, UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Wayne P. Burleson Aggressive technology scaling and an increasing demand for high performance VLSI circuits has resulted in higher current densities in the interconnect lines and increasingly higher power dissipation in the substrate. Because a significant fraction of this power is converted to heat, an exponential rise in heat density is also experienced. Different activities and sleep modes of the functional blocks in high performance chips cause significant temperature gradients in the substrate and this can be expected to further increase in the GHz frequency regime. The above scenario motivates the need for a large number of lightweight, robust and power-efficient thermal sensors for accurate thermal mapping and thermal management. We propose the use of Differential Ring Oscillators (DRO) for thermal sensing at the substrate level, utilizing the temperature dependence of the oscillation frequency. They are widely used in current VLSI for frequency synthesis and on-die process characterization; hence provide scope of reusability in design. The DRO oscillation frequency decreases linearly with increase in temperature due to the decrease in current in the signal paths. In current starved inverter topology using the 45nm technology node, the DRO based thermal sensor has a resolution of 2°C and a low active power consumption of 25µW, which can be reduced further by 60-80% by power-gating the design. Current thermal scaling trends in multilevel low-k interconnect structures suggest an increasing heat density as we move from substrate to higher metal levels. Thus, the deterioration of interconnect performance at extreme temperatures has the capability to offset the degradation in device performance when operating at higher than normal temperatures. We propose using lower-level metal interconnects to perform the thermal sensing. A resolution of ~5°C is achievable for both horizontal and vertical gradient estimation (using current generation time-digitizers). The time-digitization unit is an essential component needed to perform interconnect based thermal sensing in deep nanometer designs but it adds area and power overhead to the sensor design and limits the resolution of the wire-based sensor. We propose a novel sensor design that alleviates complexities associated with time-to-digital conversion in wire-based thermal sensing. The IBOTS or Interconnect Based Oscillator for Thermal Sensing makes use of wire-segments between individual stages of a ring-oscillator to perform thermal sensing using the oscillator frequency value as the mapping to corresponding wire temperature. The frequency output can be used to generate a digital code by interfacing the IBOTS with a digital counter. In 45nm technology, it is capable of providing a resolution of 1°C while consuming an active power of 250-360µW.

In this research a state-of-the-art micro-thermal conductivity detector is developed based on MEMS technology. Its efficient design include a miniaturized 100×2 µm bridge from doped polysilicon, suspended 10 µm away from the single crystalline silicon substrate through a thermally grown silicon dioxide sacrificial layer. The microbridge is covered by 200 nm silicon nitride layer to provide more life time. Analytical models were developed that describe the relationship between the sensor response and ambient gas material properties. To obtain local temperature distribution and accurate predictions of the sensor response, a computational three dimensional simulation based on real geometry and minimal simplifications was prepared. It was able to handle steady-state and transient state, include multiple physics such as flow, heat transfer, electrical current and thermal stresses. Two new methods of measurement for micro TCD were developed; a time resolved method based on transient response of the detector to a step current pulse was introduced that correlates time constant of the response to the concentration of gas mixture. The other method is based on AC excitation of the micro detector; the amplitude and phase of the third harmonic of the resulting output signal is related to gas composition. Finally, the developed micro-sensor was packaged and tested in a GC system and was compared against conventional and complex FID for the detection of a mixture of VOCs. Moreover compact electronics and telemetry modules were developed that allow for highly portable applications including microGC utilization in the field.

Orientador: Prof. Dr. Wendel Andrade Alves / Tese (doutorado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2015. / Este estudo versa sobre o desenvolvimento de um compósito de silicone VMQ (metil-vinil-siloxano), do tipo HTV ("high temperature vulcanizing"), com propriedades termo-solvatocrômicas provenientes da intercalação de diferentes proporções do sal iônico [NiI3(H2O)3]- na matriz polimérica. Descreve-se aqui pela primeira vez a combinação e aplicação de um compósito cromogênico em borrachas de silicone (Polidimetilvinilsiloxano). A adição dos complexos iônicos levou à formação de estruturas estáveis, com propriedades de histerese cromática de até 5h. Após a síntese e adição do complexo [NiI3(H2O)3]-, foi realizada a caracterização do compósito por diversas técnicas analíticas envolvendo espectroscopias diversas, microscopias e métodos de raios X. Por meio destas técnicas, foi possível conhecer sua inércia química e viabilizar sua aplicação prática em nível laboratorial/industrial. Desenvolveu-se a aplicação deste sistema como um sensor adaptativo, termo-solvatocrômico, o qual se revelou como uma tecnologia simples com capacidade de indicar falhas graves em isoladores poliméricos submetidos a sobreaquecimento. Com isso, abriu-se possibilidade para uso do material em inspeções preditivas em subestações e linhas de transmissão elétrica de média e alta potência. Além do uso como sensor de temperatura em sistemas elétricos, discute-se também seu potencial para aplicações em tintas indicadoras de aquecimento, displays térmicos, atenuadores de intensidade luminosa em janelas inteligentes, entre outros. / This study reports on the development of a VMQ (methylvinyl siloxane), HTV type (high temperature vulcanizing), silicone composite with thermo-solvatochromic properties arising from the intercalation of different amounts of the ionic salt [NiI3(H2O)3]- into the polymer matrix. It is described here, for the first time, the combination and application of a chromogenic composite in silicone rubbers (poly dimetyl vinyl siloxanes). The addition of ionic complexes has led to the formation of stable structures, with remarkable properties of chromic hysteresis for periods over 5 hours. After synthesis and incorporation of [NiI3(H2O)3]-, the composite was fully characterized through a wide number of analytical techniques including spectroscopy, microscopy and X-rays methods. With these techniques, it has been possible scrutinize its chemical inertia and enable its practical application at both laboratorial and industrial levels. It has been developed its application as an adaptative thermo-solvatochromic sensor which has been found to be a simple technology able to detect serious flaws in polymeric insulators undergone to overheating. Thus, new possibilities for its usage for predictive inspections in electrical substations and power transmission lines have been uncovered. In addition to the usage as a temperature sensor in electrical plants, it is also discussed the potential of the composite for applications in heating indicator inks, thermal displays and light attenuators on smart windows, among others.

This masters thesis project, "Occupancy Sensor System", was conducted at Kungliga Tekniska Högskolan (KTH), Stockholm, Sweden, during the period 2007-04-24 – 2007-12-17. The goal of the project was to design an occupancy sensor system that determines if there exists more than one person in a defined region. The output of this system is for use in a context-aware system at the KTH Center for Wireless Systems (Wireless@KTH). The system is important because there is a need for specific input to context-aware systems concerning occupancy of spaces and because this thesis has focused on a problem that enables new complex and interesting services. Additionally, the specific problem of determining not only occupancy, but if this occupancy is zero, one, many has not been widely examined previously. The significance of zero occupants indicating an empty room has already been recognized as having economic and environmental value in terms of heating, ventilating, air-conditioning, and lighting. However, there has not been an effort to differentiate between a person being alone or if more than one person is present. A context-aware system might be able to use this later information to infer that a meeting is taking place in a meeting room, a class taking place in a classroom or that an individual is alone in a conference room, class room, etc. Thus enabling context-aware services to change their behavior based upon the differences in these situations. An occupancy sensor system prototype was designed to monitor a boundary by using a thermal detector, gumstix computer, an analog to digital converter prototype board, laptop computer, and a context broker. The testing and evaluation of the system, proved it to be sound. However, there are still further improvements and tests to be made. These improvements include: dynamic configuration of the system, communication between the different system entities, detection algorithms, and code improvements. Tests measuring accuracy of a detection algorithm and determining optimal detector placement need to be performed. The next step is to design applications that use the context information provided from the occupancy sensor system and expand the system to use multiple detectors. / Examensarbetet "Occupancy Sensor System" genomfördes på Kungliga Tekniska Högskolan (KTH), Stockholm, Sverige, under perioden 2007-04-24 – 2007-12-17. Målet med examensarbetet var att designa ett sensorsystem, som avgör om ett rum är befolkat med fler än en person i ett definierat område. Resultatet av detta system är till för användning i ett kontextmedvetet system som finns i KTH Center for Wireless Systems (Wireless@KTH). Systemet är viktigt eftersom det finns ett behov för specifik input till kontextmedvetna system som berör befolkning av rum och eftersom detta examensarbete har fokuserat på ett problem som möjliggör nya komplexa och intressanta tjänster. Dessutom har det inte tidigare undersökts i vidare bemärkelse hur man kan avgöra om ett rum befolkats av noll, en eller flera personer. Betydelsen av att ett rum är obefolkat har redan ansetts ha ekonomiskt och miljöbetingat värde vad gäller uppvärming, ventilation, luftkonditionering och belysning. Däremot har det inte gjorts ansträngningar att differentiera mellan att en ensam person eller flera är närvarande. Ett kontextmedvetet system skulle kunna använda den senare nämnda informationen för att dra slutsatsen att ett möte pågår i ett mötesrum, en lektion är igång i ett klassrum o.s.v. Detta möjliggör i sin tur för kontextmedvetna tjänster att ändra på sina beteenden baserat på skillnaderna i dessa situationer. En prototyp utvecklades för att övervaka en gräns genom användningen av en termisk detektor, gumstixdator, analog till digital signalkonverterare, bärbar dator och en context broker (kontextförmedlare). Testningar och utvärderingar av systemet visade att systemet var dugligt. Flera förbättringar och tester behöver dock göras i framtiden. Dessa förbättringar inkluderar: dynamisk konfiguration av systemet, kommunikation mellan de olika systementiteterna, detektionsalgoritmer och kodförbättringar. Återstående tester inkluderar mätning av en detektionsalgoritms tillförlitlighet samt optimal placering av detektorer. Nästa steg är att utveckla applikationer som använder kontextinformationen från systemet samt att utveckla systemet till att kunna använda flera detektorer.

Thermal management has emerged as an important design issue in a range of designs from portable devices to server systems. Internal thermal sensors are an integral part of such a management system. Process variations in CMOS circuits cause accuracy problems for thermal sensors which can be fixed by calibration tables. Stand-alone thermal sensors are calibrated to fix such problems. However, calibration requires going through temperature steps in a tester, increasing test application time and cost. Consequently, calibrating thermal sensors in typical digital designs including mainstream desktop and notebook processors increases the cost of the processor. This creates a need for design of thermal sensors whose accuracy does not vary significantly with process variations. Other qualities desired from thermal sensors include low area requirement so that many of them maybe integrated in a design as well as low power dissipation, such that the sensor itself does not become a significant source of heat. In this work, we developed a process variation tolerant thermal sensor design with (i) active compensation circuitry and (ii) signal dithering based self calibration technique to meet the above requirements in 32nm technology. Results show that we achieve 3ºC temperature accuracy, with a relatively small design which compares well with designs that are currently used.

Interconnects in power module result in thermal interfaces. The thermal interfaces degrade under thermal cycling, or chemical loading. Moreover, the reliability of thermal interfaces can be especially problematic when the interconnecting area is large, which increases its predisposition to generate defects (voids, delamination, or nonuniform quality) during processing. In order to improve the quality of the bonding process, as well as to be able to accurately assess interface reliability, it would be desirable to have a simple, reliable, and nondestructive measurement technique that would produce a 2-d map of the interface thermal resistance across a large bonded area. Based on the transient thermal method of JEDEC standard 51-14, we developed a measurement technique that involves moving a thermal sensor discretely across a large-area bonded substrate and acquiring the interface thermal resistance at each location. As detailed herein, the sensor was fabricated by packaging an IGBT bare die. An analytical thermal model was built to investigate the effects of thermal sensor packaging materials and structural parameters on the sensitivity of the measurement technique. Based on this model, we increased the detection sensitivity of the sensor by modifying the size of the sensor substrate, the material of the sensor substrate, the size of the IGBT bare die, the size of the heat sink, and the thermal resistance between sample and the heat sink. The prototype of the thermal sensor was fabricated by mounting Si IGBT on copper substrate, after which the Al wires were ultrasonic bonded to connect the terminals to the electrodes. The sensor was also well protected with a 3-d printed fixture. Then the edge effect was investigated, indicating the application of the thermal sensor is suitable for samples thinner than the value in TABLE 2 3. The working principle of the movable thermal sensor – Zth measurement and its structure function analysis – was then evaluated by sequence. The Zth measurement was evaluated by measuring the Zth change of devices induced by degradation in sintered silver die-attach layer during temperature cycling. At the end of the temperature cycling, failure modes of the sintered silver layer were investigated by scanning electron microscope (SEM) and X-ray scanning, to construct a thermal model for FEA simulation. The simulation results showed good agreement with the measured Zth result, which verified the accuracy of the test setup. The sensitivity of structure function analysis was then evaluated by measuring thermal resistance (Rth) of interface layers with different thermal properties. The structure function analysis approach successfully detected the Rth change in the thermal interface layer. The movable thermal sensor was then applied for 2d-mapping of the interface Rth of a large-area bonded substrate. Examining the test coupons bonded by sintered silver showed good and uniform bonding quality. The standard deviation of Rth is about 0.005 K/W, indicating the 95% confidence interval is about 0.01 K/W, which is commonly chosen as the error of measurement. The sensitivity of the movable thermal sensor was evaluated by detecting defects/heat channels of differing sizes. The 2-d mapping confirmed that the thermal sensor was able to detect defect/heat channel sizes larger than 1x1 mm2. The accuracy of the sensitivity was verified by FEA simulation. Moreover, the simulated results were consistent with the measured results, which indicates that the movable sensor is accurate for assessing interface thermal resistance. In summary, based on structure function analysis of the transient thermal impedance, the concept of a movable thermal sensor was proposed for two-dimensional mapping of interface thermal resistance. (1) Preliminary evaluation of this method indicated both transient thermal impedance and structure function analysis were sensitive enough to detect the thermal resistance change of thermal interface layers. With the help of transient thermal impedance measurement, we non-destructively tested the reliability of sintered silver die-attach layer bonded on either Si3N4 AMB or AlN DBA substrates. (2) An analytical thermal model was constructed to evaluate the design parameters on the sensitivity and resolution of the movable thermal sensor. A detailed design flow chart was provided in this thesis. To avoid edge effect, requirements on thickness and materials of test coupon also existed. Test coupon with smaller thermal conductivity and larger thickness had a more severe edge effect. (3) The application of the movable sensor was demonstrated by measuring the 2-d thermal resistance map of interface layers. The results indicated for bonded copper plates (k = 400 W/mK) with thickness of 2 mm, the sensor was able to detect defect/heat channel with size larger than 1x1 mm2. / Doctor of Philosophy / Interconnects in power module result in thermal interfaces. The thermal interfaces degrade during operation and their reliability can be especially problematic when the interconnecting area is large. In order to improve the quality of the bonding process, as well as to be able to accurately assess interface reliability, it would be desirable to have a simple, reliable, and nondestructive measurement technique that would produce a 2-d map of the interface thermal resistance across a large bonded area. Based on the transient thermal method of JEDEC standard 51-14, we developed a measurement technique that involves moving a thermal sensor discretely across a large-area bonded substrate and acquiring the interface thermal resistance at each location. As detailed herein, the sensor was fabricated by packaging an IGBT bare die, which allowed us to get a 2-d map of the interface thermal resistance. A thermal model was also constructed to guide the design of the sensor, to increase its performance. Moreover, the preliminary test of the test setup was conducted to prove its feasibility for the sensor. Eventually, the sensor’s performance and application was demonstrated by measuring the 2-d thermal resistance map of the bonded interfaces.

Le contrôle des écoulements vise à modifier le comportement naturel d’un écoulement fluidique. Dans le domaine des transports, contrôler les phénomènes fluidiques tels que le décollement peut permettre d’économiser du carburant, d’améliorer les performances des véhicules ou encore d’assurer davantage la sécurité des passagers. Dans ce contexte, des capteurs avec de fines résolutions temporelle et spatiale sont requis afin de connaître l’écoulement à contrôler et adapter en temps réel le contrôle. Dans ce travail, l’objectif a été de développer des micro-capteurs de frottement et de pression pour les mesures en écoulements turbulents et le contrôle de décollement. Tout d’abord un micro-capteur calorimétrique a été conçu et réalisé par des techniques de microfabrication pour mesurer simultanément le frottement pariétal et la direction de l’écoulement. Le micro-capteur a ensuite été intégré en paroi d’une soufflerie afin de réaliser son étalonnage statique et dynamique et d’étudier sa sensibilité à la direction de l’écoulement. Troisièmement, le micro-capteur calorimétrique a été utilisé pour caractériser des écoulements décollés. Plusieurs micro-capteurs avec électronique miniaturisée ont été intégrés avec succès dans une maquette de volet et des essais de contrôle actif ont été réalisés. Enfin, la quatrième partie concerne le développement d’un micro-capteur de pression et d’un micro-capteur multi-paramètres réunissant les deux technologies. L’ensemble de ces micro-capteurs ont été caractérisés avec succès et montrent des résultats prometteurs pour caractériser les écoulements turbulents et permettre la mise en place de contrôle d’écoulement en boucle fermée. / Flow control aims at artificially changing the natural behaviour of a flow. In transport industries, controlling fluidic phenomena such as boundary layer separation allows saving fuel and power, improving vehicles performances or insuring passenger’s safety. In this context, sensors with accurate spatial and temporal resolution are required. Such devices enable to estimate the flow to control and allow real-time adaptation of the control. In this work, the objective is to develop wall shear stress and pressure micro-sensors for turbulent flows measurements and flow separation control.Firstly, a calorimetric micro-sensor was designed and realized using micromachining techniques for measuring simultaneously the wall shear stress amplitude and the flow direction. Secondly, the micro-sensor was flush-mounted at the wall of a wind tunnel for static and dynamic calibrations. Thirdly, it was used to characterized separated flows. Several configurations were studied: separation on airfoil profile, separation and reattachment downstream a 2D square rib and the separation on a flap model. Several micro-sensors with embedded electronics were successfully integrated on a flap model and active flow control experiments were performed. Finally, the fourth part of the document concerns the development of a pressure micro-sensor and the development of a multi-parameter micro-sensor combining both technologies.All these micro-sensors have been successfully realized and characterized and demonstrate promising results for measuring turbulent flows and implementing closed loop reactive flow control

熱紅外波段在遙感探測中佔有相當重要的地位，因其不受日夜條件限制，且因溫度變化時常具有與自然環境相關的特殊意義，使熱紅外影像可應用於測量、環境監控、都市開發、災害防治等領域。 在判釋遙測影像之前，通常必先確定各波段影像的幾何性質一致，若想將熱紅外影像與可見光影像套疊，須先率定蒐集熱影像之儀器，使影像受儀器本身的影響減到最低。本研究以FLIR-T360紅外線熱像儀為研究對象，探討熱像儀的成像特性，且嘗試率定與改正蒐集之熱影像。 率定熱像儀的實驗可分為幾何與輻射兩方面，幾何方面使用改良型的實地率定法，以求取熱像儀的內方位參數；輻射方面則使用實地調查法，求得控制點溫度，利用拍攝控制點蒐集多筆資料，擬合出輻射改正模型；本文亦展示熱影像幾何以及輻射改正後的成果。 / Thermal infrared data is important when conducting remote sensing investigation, for it could be acquired both in day and night. The change of temperature has characteristic significance of representing. So the thermal infrared images are used not only in the domain of surveying, but also in the environment monitoring, the urban development, and the disaster prevention. Before interpreting the remote sensing data, one would make sure that each image of bands has similar image geometry. Calibrating such geometry could prove that the effect from the lens distortion had been minimized. In such case, calibrated thermal images are necessary to guarantee that the image coordinates will correspond with the space coordinates as other bands. A thermal sensor, FLIR-T360 has been calibrated in this research. Two aspects of calibration executed are geometric and radiometric. A conventional calibrated template has been improved for using in the geometric aspect. The thermal sensor’s interior orientation elements were then found by using a field method. In the radiometric aspect, in situ method has been employed to determine temperatures of the chosen control points. The result of correction in geometric and radiometric aspect are also shown and discussed in this study.