Nano scale processing of IC chips has become the prime production technique as the microelectronic industry aims towards scaling down product dimensions while increasing accuracy and performance. Accurate control of temperature and a good monitoring mechanism for thickness of the deposition layers during epitaxial growth are critical parameters influencing a good yield. The two-fold objective of this thesis is to establish the feasibility of an alternative to the current pyrometric and ellipsometric techniques to simultaneously measure temperature and thickness during wafer processing. TAP-NDE is a non-contact, non-invasive, laser-based ultrasound technique that is employed in this study to contemporarily profile the thermal and spatial characteristics of the wafer. The Gabor wavelet transform allows the wave dispersion to be unraveled and the group velocity of individual frequency components to be extracted from the experimentally acquired time waveform. The thesis illustrates the formulation of a theoretical model that is used to identify the frequencies sensitive to temperature and thickness changes. The group velocity of the corresponding frequency components is determined and their corresponding changes with respect to temperature for different thickness are analytically modeled. TAP-NDE is then used to perform an experimental analysis on Silicon wafers of different thickness to determine the maximum possible resolution of TAP-NDE towards temperature sensitivity, and to demonstrate the ability to differentiate between wafers of different deposition layer thickness at temperatures up to 600?C. Temperature resolution is demonstrated for ?10?C resolution and for ?5?C resolution; while thickness differentiation is carried out with wafers carrying 4000? and 8000? of aluminum deposition layer. The experimental group velocities of a set of selected frequency components extracted using the Gabor Wavelet time-frequency analysis as compared to their corresponding theoretical group velocities show satisfactory agreement. As a result of this work, it is seen that TAP-NDE is a suitable tool to identify and characterize thickness and temperature changes simultaneously during thermal annealing that can replace the current need for separate characterization of these two important parameters in semiconductor manufacturing.

Die Arbeit stellt neu entwickelte Röntgenbeugungsmethoden vor, mit deren Hilfe der Verzerrungszustand des Kristallgitters von Halbleiter-Wafern und -Bauteilen im Detail charakterisiert werden kann. Hierzu werden die aussergewöhnlichen Eigenschaften der an modernen Synchrotrons wie der ESRF (Grenoble) verfügbaren Röntgenstrahlung genutzt. <br>Im ersten Teil der Arbeit werden Röntgen-Diffraktometrie und -Topographie zu einer Untersuchungsmethode kombiniert, mit der die makroskopische Krümmung von Halbleiter-Wafern ebenso wie ihre mikroskopische Defektstruktur abgebildet werden kann. Der zweite Teil ist der Untersuchung von epitaktisch gewachsenen und geätzten Oberflächengittern mit Abmessungen im Submikrometer-Bereich gewidmet. Die unterschiedlichen Gitterkonstanten der beteiligten Halbleitermaterialien führen zu einem inhomogenen Verzerrungsfeld in der Probe, das sich im Röntgenbild durch eine charakteristische Verformung des Beugungsmusters in der Umgebung der Bragg-Reflexe äussert. Die Analyse der experimentell gemessenen Beugungsmuster geschieht mit Hilfe eines neu entwickelten Simulationsverfahrens, das Elastizitätstheorie und eine semi-kinematische Röntgenbeugungstheorie miteinander verbindet. Durch quantitativen Vergleich der Simulationsergebnisse mit den Messdaten kann auf den genauen Verlauf des Verzerrungsfeldes in den Proben zurückgeschlossen werden. Dieses Verfahren wird erfolgreich auf verschiedene Halbleiter-Probensysteme angewendet, und schliesslich auch auf die Untersuchung von akustischen Oberflächenwellen in Halbleiterkristallen übertragen. / This thesis presents newly developed X-ray methods which can be used to characterize in detail the state of distortion of the crystal lattice in semiconductor wafers, devices and nanostructures. The methods use the extraordinary properties of the X-rays available from modern synchrotron sources such as the ESRF (Grenoble). <br>In the first part of the thesis, X-ray diffractometry and X-ray topography are combined into a new method, called X-ray rocking curve imaging, which allows to image the macroscopic curvature of semiconductor wafers as well as the underlying microscopic defect structure. The second part of the thesis deals with the investigation of epitaxially grown and subsequently etched semiconductor gratings with lateral periods below the micrometer. The lattice mismatch between the different materials used in heteroepitaxy leads to a non-uniform strain field in the sample, which is reflected in a characteristic distortion of the X-ray diffraction pattern around each Bragg peak. The experimental data are evaluated with the help of a newly developed simulation procedure which combines elasticity theory with a semi-kinematical theory of X-ray diffraction. From a quantitative comparison of measured and simulated data the detailed shape of the strain field in the samples can be deduced. This procedure is used successfully for the structural characterization of different types of semiconductor gratings, and is finally applied also to the investigation of surface acoustic waves in crystals.

Nano scale processing of IC chips has become the prime production technique as the microelectronic industry aims towards scaling down product dimensions while increasing accuracy and performance. Accurate control of temperature and a good monitoring mechanism for thickness of the deposition layers during epitaxial growth are critical parameters influencing a good yield. The two-fold objective of this thesis is to establish the feasibility of an alternative to the current pyrometric and ellipsometric techniques to simultaneously measure temperature and thickness during wafer processing. TAP-NDE is a non-contact, non-invasive, laser-based ultrasound technique that is employed in this study to contemporarily profile the thermal and spatial characteristics of the wafer. The Gabor wavelet transform allows the wave dispersion to be unraveled and the group velocity of individual frequency components to be extracted from the experimentally acquired time waveform. The thesis illustrates the formulation of a theoretical model that is used to identify the frequencies sensitive to temperature and thickness changes. The group velocity of the corresponding frequency components is determined and their corresponding changes with respect to temperature for different thickness are analytically modeled. TAP-NDE is then used to perform an experimental analysis on Silicon wafers of different thickness to determine the maximum possible resolution of TAP-NDE towards temperature sensitivity, and to demonstrate the ability to differentiate between wafers of different deposition layer thickness at temperatures up to 600?C. Temperature resolution is demonstrated for ?10?C resolution and for ?5?C resolution; while thickness differentiation is carried out with wafers carrying 4000? and 8000? of aluminum deposition layer. The experimental group velocities of a set of selected frequency components extracted using the Gabor Wavelet time-frequency analysis as compared to their corresponding theoretical group velocities show satisfactory agreement. As a result of this work, it is seen that TAP-NDE is a suitable tool to identify and characterize thickness and temperature changes simultaneously during thermal annealing that can replace the current need for separate characterization of these two important parameters in semiconductor manufacturing.

Photovoltaic manufacturing is material intensive with the cost of crystalline silicon wafer, used as the substrate, representing 40% to 60% of the solar cell cost. Consequently, there is a growing trend to reduce the silicon wafer thickness leading to new technical challenges related to manufacturing. Specifically, wafer breakage during handling and/or transfer is a significant issue. Therefore improved methods for breakage-free handling are needed to address this problem. An important pre-requisite for realizing such methods is the need for fundamental understanding of the effect of handling device variables on the deformation, stresses, and fracture of crystalline silicon wafers. This knowledge is lacking for wafer handling devices including the Bernoulli gripper, which is an air flow nozzle based device. A computational fluid dynamics model of the air flow generated by a Bernoulli gripper has been developed. This model predicts the air flow, pressure distribution and lifting force generated by the gripper. For thin silicon wafers, the fluid model is combined with a finite element model to analyze the effects of wafer flexibility on the equilibrium pressure distribution, lifting force and handling stresses. The effect of wafer flexibility on the air pressure distribution is found to be increasingly significant at higher air flow rates. The model yields considerable insight into the relative effects of air flow induced vacuum and the direct impingement of air on the wafer on the air pressure distribution, lifting force, and handling stress. The latter effect is found to be especially significant when the wafer deformation is large. In addition to silicon wafers, the model can also be used to determine the lifting force and handling stress produced in other flexible materials. Finally, a systematic approach for the analysis of the total stress state (handling plus residual stresses) produced in crystalline silicon wafers and its impact on wafer breakage during handling is presented. Results confirm the capability of the approach to predict wafer breakage during handling given the crack size, location and fracture toughness. This methodology is general and can be applied to other thin wafer handling devices besides the Bernoulli gripper.

Dans les processus de fabrication de semi-conducteurs, différents types des contrôles existent pour maîtriser les procédés et garantir la qualité du produit final. Ces travaux de thèse s’intéressent aux contrôles de défectivité qui visent à maîtriser le risque sur les équipements de production. L'indicateur utilisé est le nombre de produits traités par un équipement depuis la date du dernier produit contrôlé. On s’intéresse à la maîtrise et la réduction du risque sur les équipements de production. Pour cela, différentes stratégies de sélection des lots existent et peuvent être classifiées selon leur capacité à intégrer la dynamique d'une unité de fabrication. Dans les stratégies de sélection dynamique, les lots sont contrôlés en temps réel et en optimisant un critère. Ces stratégies sont récentes et sont beaucoup plus efficaces que les stratégies précédentes, mais aussi plus complexe à mettre en œuvre. Dans ce cadre, nous avons proposé et validé industriellement différents algorithmes pour identifier les lots à relâcher (à ne pas contrôler) dans les files d'attente des lots en défectivité. Nous avons aussi développé et implémenté un modèle d'optimisation de la capacité pour l’atelier de défectivité, qui permet d’évaluer l’impact de paramètres critiques (e.g. plan de production, positions des opérations de contrôles dans la gamme de fabrication, valeurs des limites de risques) dans la gestion du risque global de l'unité de fabrication. / In semiconductor manufacturing, several types of controls are required to ensure the quality of final products. In this thesis, we focus on defectivity inspections, which aim at monitoring the process for defect reduction and yield improvement. We are interested in managing and reducing the risk on process tools (i.e. number of wafers at risk) during fabrication. To reduce this risk, inspection operations are performed on products. However, because inspection operations directly impact the cycle times of products, sampling strategies are used to reduce the number of inspected lots while satisfying quality objectives. Several sampling techniques exist and can be classified according to their capability to deal with factory dynamics. Dynamic sampling strategies have recently been proposed, in which lots to inspect are selected in real time while considering the current production risk. These strategies are much more efficient than previous strategies but more complex to design and implement. In this thesis, a novel approach to select the lots to inspect is proposed. Multiple algorithms have been proposed and validated to efficiently manage the defect inspection queues by skipping (i.e. releasing) lots that do no longer bring enough information. In order to support strategic and tactical decisions, an optimization model for defect inspection capacity planning is also proposed. This model calculates the required defect inspection capacity to ensure the risk limits on process tools when the production conditions change. Industrial results show significant improvements in terms of risk reduction without increasing defect inspection capacity.

The main objective of the diploma thesis is to determine the perception of the Kolonáda brand by young people and how to become relevant for them. This would not be possible without specific knowledge of the whole market and without knowledge regarding the segments of biscuits and wafers consumers. The market segmentation is based on MML-TGI data collected by the research agency Median, five segments are revealed. I have also implemented my own questionnaire research on a sample of 480 respondents aged up to 34 years including. Based on the results of the practical part, recommendations for the Kolonáda brand are proposed -- how to become more relevant for the young consumers and stay attractive for the current consumers.

Objective: To assess the safety and effectiveness of bis-chloroethylnitrosourea (BCNU) wafers in elderly patients with recurrent glioblastoma (GBM). Methods: Patients with recurrent GBM operated on between 2007 and 2014 were divided into 3 groups: >65 years with BCNU wafer implantation, >65 years without BCNU wafer implantation, and ≤ 65 years with BCNU wafer implantation. We compared survival and complications. Results: A total of 79 patients were identified: 24 in the older BCNU group (median age 68.2 years, 33.3% with a methylated MGMT promoter), 16 in the older non-BCNU group (median age 68.6 years, 31.3% with a methylated MGMT promoter), and 39 in the younger BCNU group (median age 56.8 years). Survival after progression was 9.2 months in the elderly BCNU group and 7.6 months in the elderly non-BCNU group ( p = 0.34); overall survival was 17.2 and 15.9 months, respectively ( p = 0.35). We found a tendency toward a higher rate of seizures and pneumonia in the older BCNU group. Conclusion: BCNU wafer implantation after resection of recurrent GBM is a reasonably safe treatment in patients aged >65 years. Seizures and systemic infections may occur more frequently, but the trade-off is still favorable as survival may be influenced positively. Higher age should not be regarded as a contraindication for BCNU wafers.

L’imagerie multispectrale permet d’améliorer la détection et la reconnaissance de cibles dans les applications de surveillance. Elle consiste à analyser des images de la même scène acquises simultanément dans plusieurs bandes spectrales grâce à un filtrage. Cette thèse étudie la possibilité de réaliser une matrice de 4 filtres Fabry Pérot (FP) intégrés 3D et ajustables par actionnement électrostatique dans le domaine visible-proche infrarouge. Les miroirs fixes des filtres FP sont des multicouches ZnS/YF₃ déposés sur un wafer de borosilicate, et les miroirs mobiles sont des membranes multicouches PECVD SiNH/SiOH encastrées sur une structure mobile très compacte micro-usinée dans un wafer en silicium. Les performances optiques des filtres FP ont été optimisées en prenant en compte la dissymétrie et le déphasage à la réflexion des miroirs. La structure mobile a été modélisée par éléments finis pour minimiser ses déformations lors de l’actionnement. Les étapes critiques des procédés de fabrication des miroirs mobiles en technologie Si ou SOI ont été mises au point : i) la fabrication et la libération par gravures profondes DRIE et XeF₂ des membranes multicouches avec une contrainte résiduelle ajustée par recuit et une réflectance voisine de 50% dans une large gamme spectrale, ii) le contrôle des vitesse de la gravure DRIE avec des motifs temporaires permettant la gravure simultanée de motifs de largeur et de profondeur variables, et iii) la délimitation de motifs sur surfaces fortement structurées à l’aide de pochoirs alignés mécaniquement ou de films secs photosensibles. Ces travaux ouvrent la voie vers une réalisation complète d’une matrice de filtres FP intégrés 3D. / Multispectral imaging is used to improve target detection and identification in monitoring applications. It consists in analyzing images of the same scene simultaneously recorded in several spectral bands owing to a filtering. This thesis investigates the possibility to realize, an array of four 3D integrated Fabry-Perot (FP) filters that are tunable in the visible-near infrared range by electrostatic actuation. The fixed mirrors of the FP filters are ZnS/YF₃ multilayers deposited on a borosilicate wafer, and the movable mirrors are PECVD SiNH/SiOH multilayer membranes clamped in a very compact movable structure micromachined in a Si wafer. A 3rd glass wafer is used for filters packaging. Optical performances of the FP filters have been optimized by taking into account the asymmetry and the reflection phase shift of the mirrors and the mobile structure has been modeled by finite elements analysis notably to minimize its deformation during actuation. The critical steps of the movable mirrors fabrication process in Si or SOI technology have been developed : i) the fabrication and the release by DRIE and XeF₂ etching of 8 or 12 layers membranes with a residual stress tunable by annealing and a reflectance close to 50% in broad wavelength range (570-900nm), ii) the control with temporary patterns of the simultaneous deep etching of patterns with different widths and depths, and iv) various patterning techniques on highly structured surfaces based on shadow masks (with mechanical alignment) or laminated photosensitive dry films. These results open the way towards the full realization of an array of 3D integrated FP filters.

Les cellules photovoltaïques à base de silicium cristallin représentent plus de 90% du marché photovoltaïque mondial. Des architectures de cellules à haut rendement de conversion sont actuellement développées. Pour atteindre leurs performances maximales, ces architectures nécessitent néanmoins une amélioration des propriétés électriques des substrats de silicium cristallin. Les objectifs de cette thèse sont d’identifier les défauts limitant les propriétés électriques de ces substrats, de comprendre les mécanismes menant à leur formation et de proposer des moyens permettant leur neutralisation. Les matériaux étudiés sont des plaquettes de silicium Czochralski de type n, généralement utilisé pour les applications à haut rendement. Le four de tirage Czochralski a d’abord été modélisé afin de comprendre comment le passé thermique subi par le lingot de silicium lors de la cristallisation affecte la génération des défauts. Ces travaux ont été confirmés via des confrontations avec des données expérimentales, en utilisant une méthode originale développée dans le cadre de ce travail. Nous avons ensuite étudié l’influence du budget thermique lié aux procédés de fabrication des cellules sur la population de défauts. Nous avons ainsi pu montrer que la nature des défauts limitant les propriétés électriques du silicium était grandement modifiée selon le procédé de fabrication de cellules utilisé. Nous avons en outre mis en évidence une dégradation inattendue des propriétés électriques du silicium Czochralski de type n sous illumination, liée à la formation d’un défaut volumique inconnu. Les conditions de formation et de suppression de ce défaut ont été étudiées en profondeur. Enfin, les principaux défauts limitant les propriétés électriques du silicium ayant été identifiés et les mécanismes menant à leur formation compris, nous proposons dans un dernier chapitre des nouvelles techniques de caractérisation permettant de détecter les plaquettes défectueuses en début de ligne de production de cellules photovoltaïques, et ce à une cadence industrielle. / Photovoltaic solar cells based on crystalline silicon represent more than 90% of the worldwide photovoltaic market. High efficiency solar cell architectures are currently being developed. In order to allow their maximal performances to be reached, the electronic properties of their crystalline silicon substrate must however be enhanced. The goals of the present work are to identify the defects limiting the electronic properties of the substrate, to understand the mechanisms leading to their formation and to propose routes for their neutralization. The studied materials are n-type Czochralski silicon wafers, usually used as substrates for high efficiency photovoltaic applications. The Czochralski puller was first modeled in order to understand how the thermal history experienced by the silicon ingot during crystallization affects the defects generation. This study were validated through the comparison with experimental data using an original method developed in the frame of this work. We then studied the influence of the thermal budget associated to solar cell fabrication processes on the defects population. We thus showed that the nature of lifetime-limiting defects was completely changed depending on the solar cell fabrication process. Besides, we evidenced an unexpected degradation of the electronic properties of n-type Czochralski silicon under illumination, related to the formation of an unknown bulk defect. The formation and deactivation features of this defect were extensively studied. Finally, the main limiting defects being identified and the mechanisms resulting in their formation understood, we propose in a last chapter new characterization techniques for the detection of defective wafers at the beginning of production lines at an industrial throughput.

<p>The objective of this thesis was to investigate and characterize the interaction between blood proteins and different surfaces with emphasis on protein adsorption to bioceramics and model surfaces. Special effort was made to monitor the spontaneous and selective adsorption of proteins from human plasma and to examine the orientation, conformation and functional behavior of single proteins after adsorption. </p><p>Five different ceramic biomaterials: alumina (Al₂O₃), zirconia (ZrO₂), hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂) and two glass-ceramics, AP40 (SiO₂-CaO-Na₂O-P₂O₅-MgO-K₂O-CaF₂) and RKKP (AP40 with Ta₂O₃-La₂O₃), were exposed to human plasma and their protein binding capacities and affinities for specific proteins were studied by chromatography, protein assays, two-dimensional gel electrophoresis and Western blotting. The studies showed that all materials adsorbed approximately the same high amount of plasma proteins and that they therefore should be fully covered by proteins in an <i>in vivo</i> setting. The adsorbed proteins were different for most materials which could explain their previously observed different levels of tissue integration <i>in vivo</i>. </p><p>Four of the proteins that behaved differently, ceruloplasmin, prothrombin, α₂-HS-glycoprotein and α₁-antichymotrypsin, were selected for characterization with atomic force microscopy and ellipsometry. The studies, which were performed on ultraflat silicon wafers (silica), showed that the proteins oriented themselves with their long axis parallel to the surface or as in case of ceruloplasmin with one of its larger sides towards the surface. All of them had globular shapes but other conformational details were not resolved. Furthermore, prothrombin (none of the others) formed multilayers at high proteins concentrations. </p><p>The functional behaviour of the adsorbed proteins, referring to their cell binding and cell spreading capacity on silica and a positive cell adhesion reference surface (Thermanox®), was affected by the underlying substrate. Ceruloplasmin, α₂-HS-glycoprotein and α₁-antichymotrypsin stimulated cell attachment to silica, but suppressed attachment to Thermanox®. Prothrombin stimulated cell attachment to both surfaces. The attachment was in most cases mediated both by cell membrane-receptors (integrins) and by non-specific interactions between the cell and the material. </p><p>This thesis showed that the compositional mixture, orientation, conformation and functional behavior of the adsorbed proteins are determined by the properties of the underlying surface and if these parameters are controlled very different cellular responses can be induced.</p>