As humanity continues its expansion into space, the understanding of the near-Earth space environment has never been more critical. As the ionosphere and thermosphere form the boundary between Earth's atmosphere and outer space, characterization of these regions is critical to understanding geospace. The Ionospheric Connection Explorer (ICON), launched in 2019, sought to establish the effects of forcing on the ionosphere and thermosphere from below and above, in part by using observations of ultraviolet airglow, which have long been used as a tool for making remote sensing observations of the upper atmosphere. The Extreme Ultraviolet Spectrometer (EUV) instrument was included on ICON to measure atmospheric airglow between 54 and 88 nm in order to estimate the density and structure of the ionosphere. In this work, we analyze the EUV observations throughout the ICON mission, characterizing the signal observed at various wavelengths during normal operations and during nadir and lunar calibrations. We use the ICON EUV data to develop the first algorithm for retrieval of neutral densities from EUV airglow. / Doctor of Philosophy / As humanity continues its expansion into space, the understanding of the near-Earth space environment has never been more critical. The neutral (thermosphere) and charged (ionosphere) particles in the upper atmosphere, around the altitude where satellite orbit, play a key role as the boundary between Earth and space. The Ionospheric Connection Explorer (ICON), launched in 2019, sought to establish how the ionosphere and thermosphere change over time. It measured the density of particles using light emitted from the atmosphere by chemical reactions (airglow). Extreme Ultraviolet (EUV) light is highly energetic, almost as much as X-rays, and the EUV airglow emitted by the atmosphere at certain can be used to detect O^+. In this work, we examine the measurements from the ICON EUV detector at various wavelengths to determine what other particles can be seen. Notably, we find that the measurements contain information about neutral atomic oxygen and molecular nitrogen. We develop a technique for using the EUV airglow brightness to measure the amount of O and N_2, the first of its kind.

La lithographie électronique multifaisceaux (ou multi e-beam) en cours de développement est pressentie comme une alternative à la photolithographie 193 nm à immersion (193i nm) pour la production des circuits intégrés des noeuds technologiques avancés (14 nm et au-delà). Elle se présente également comme un concurrent potentiel à la photolithographie sous rayonnement EUV (13,5 nm) qui, elle aussi, est en cours de développement. Cependant, le développement de cette technologie doit faire face à plusieurs obstacles. Parmi eux, on a la contamination des optiques électroniques induite par le redépôt des molécules dégazées de la résine au cours de l‟exposition. Ces dépôts conduisent à la croissance d‟une couche carbonée en surface et à l‟intérieur des trous de ces optiques. Cette couche de contamination a tendance à diminuer la transmission des optiques et, par conséquent, diminuer les performances lithographiques de l‟outil (débit, uniformité des CD, rugosité, etc.). Il est donc indispensable de comprendre les mécanismes qui gouvernent le dégazage et la croissance de la couche de contamination afin d‟être en mesure de prédire son rôle sur les dérives des procédés et de l‟équipement. Tel a été l‟axe conducteur de ces travaux de thèse. Dans un premier temps, nous avons réalisé l‟état de l‟art des travaux déjà effectués dans le cas de la technique de lithographie EUV. Ensuite, nous avons conçu et fabriqué un banc de tests et développé, en parallèle, les méthodologies permettant de réaliser les études de dégazage des résines et de contamination induite sur des dispositifs simulateurs d‟optiques électroniques, appelés « mimics ». Puis, dans les conditions opératoires similaires à la plateforme Matrix développée par MAPPER Lithography, nous avons évalué le dégazage des résines de différentes formulations et mesuré la contamination induite par chacune de ces formulations sur les mimics à l‟aide du banc de tests développé. Enfin, nous avons proposé un modèle analytique permettant de prédire la croissance du film de contamination à l‟intérieur des trous du mimic en fonction des paramètres d‟exposition. / The development of multiple e-beam lithography equipment is foreseen as an alternative to the 193i nm immersion photolithography for the advanced technological node (less than 14 nm). This next generation lithography is a potential challenger to the EUV (13.5 nm) lithography which is also under development. However, this technology faces important challenges in controlling the contamination of the electron optics due to the adsorption of molecules outgassed from resist under exposure and the subsequent formation of a carbonaceous film on optics surface. This contamination layer can lead to the transmission loss of the optics and, consequently, degrade the tool lithographic performances (throughput, CD uniformity, Line Width Roughness, etc.). It is thus important to understand the resist outgassing and induced contamination mechanisms in order to predict their effect on the process drifts. That was the driver axis of these thesis works. Firstly, we performed the state of the art related to the works already published in the EUV lithography case. Secondly, we designed and built-up an experimental setup and developed, in parallel, the methods allowing to study the mechanisms of resist outgassing and induced contamination on electron optics simulators, called “mimic”. Thirdly, we assessed the outgassing of several resist formulations in the same operating conditions as in the Matrix platform developed by MAPPER Lithography. We also measured the induced contamination layer on the mimics for each resist formulation using the developed experimental setup. And finally, we proposed an analytical model that allows to predict the contamination film growth inside mimic holes during exposure.

Ce travail présente l’étude d'une méthode de recherche utilisable en milieu industriel dessources de contamination chimique des pompes à vide équipant les lithographes EUV. Cetravail porte sur la problématique d’une éventuelle contamination carbonée introduite par lesystème de pompage et, notamment, par la turbine et le stator.A partir d’une caractérisation détaillée par chromatographie et spectroscopie dephotoémission de la contamination résiduelle issue du procédé de production, une procédured’analyse par spectrométrie de masse en phase gazeuse (RGA) utilisable en milieu industriel aété mise en oeuvre. En particulier, la possibilité de varier la température de l’échantillonpendant la mesure permet de caractériser la contamination carbonée résiduelle en étudiant lesprocédés physico-chimiques qui en sont à l’origine.Après avoir démontré l’efficacité du nettoyage final à éliminer les résidus des huiles de coupet avoir identifié la contamination organique résiduelle comme résidu du seul procédé denettoyage industriel, une copie « in vitro » de ce nettoyage a été développée : cela a permis demieux le caractériser en étudiant l’impact de plusieurs paramètres.L’influence de la concentration de lessive et de la procédure de séchage sur la contaminationcarbonée résiduelle a ainsi été étudiée. Une analyse de la contamination en phase gazeuse(RGA et TD-GCMS) ainsi qu’une caractérisation XPS de la surface des échantillons ont étéfaites. L’analyse de l’ensemble de ces résultats a permis d’établir un lien direct entre laconcentration de lessive utilisée et la contamination organique résiduelle. De plus,l’importance d’un séchage à haute température a été démontrée en mettant en évidence laprésence de plusieurs facteurs qui contribuent à la contamination résiduelle. / This work presents the study of a research method of the contamination sources of EUVLturbo molecular pumps, suitable for the industrial environment. This study deals with theproblem of a possible carbon contamination due to the pumping system and in particular tothe rotor and the stator.After a detailed characterisation of the production process residual contamination by TDGCMS/FID and XPS, a RGA procedure suitable for industrial environment has beendeveloped. The possibility to change the sample temperature during the measure lets tocharacterise the residual carbon contamination by investigating its primal physic-chemicalphenomena.The identification of the whole production process residual contamination demonstrates theefficacy of the industrial cleaning step to clean lubricants residuals. In order to bettercharacterise the cleaning step residual contamination, we developed an “in vitro” copy of theindustrial cleaning step.Thanks to the temperature variable RGA analysis of the residual contamination, we couldpoint out several contributions to carbon contamination and we could connect thesecontributions to different cleaning parameters.Detergent concentration as well as different drying procedure impact on residual carboncontamination has been studied. RGA and TD-GCMS/FID analysis as well as XPS surfacecharacterization have been performed. These analyses show a direct connection between thedetergent concentration used in the cleaning step and the residual carbon contamination.Furthermore, the importance of a high temperature drying step has been demonstrated.

We analyse solar extreme ultraviolet (EUV) irradiance observed by the Solar EUV Experiment (SEE) onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, and solar proxies (the F10.7 index, and Mg-II index), and compare their variability with the one of the global mean Total Electron Content (GTEC). Cross-wavelet analysis confirms the joint 27 days periodicity in GTEC and solar proxies. We focus on a comparison for solar minimum (2007-2009) and maximum (2013-2015) and find significant differences in the correlation during low and high solar activity years. GTEC is delayed by approximately 1-2 days in comparison to solar proxies during both low and high solar activity at the 27 days solar rotation period. To investigate the dynamics of the delay process, Coupled Thermosphere Ionosphere Plasmasphere electrodynamics model simulations have been performed for low and high solar activity conditions. Preliminary results using cross correlation analysis show an ionospheric delay of 1 day in GTEC with respect to the F10.7 index during low and high solar activity. / Wir analysieren vom Solar Extreme Ultraviolet Experiment (SEE) an Bord des Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) Satelliten gemessene solare EUV-Irradianzen, solare Proxies (den F10.7-Index und denMg-II-Index), und vergleichen deren Variabilität mit derjenigen des global gemittelten Gesamtelektronengehalts (GTEC). Kreuzwaveletanalysen bestätigen eine gemeinsame Variabilität im Periodenbereich der solaren Rotation (27 Tage). Wir vergleichen insbesondere den Zusammenhang während des solaren Minimums (2007- 2009) und Maximums (2013-2015), wobei signifikante Unterschiede der Korrelation zwischen solaren und ionosphärischen Parametern auftreten. Es tritt eine Verzögerung der Maxima und Minima von GTEC gegenüber denjenigen der solaren Proxies von einem Tag sowohl im solaren Minimum als auch im solaren Maximum auf.

La résonance cyclotronique ionique est utilisée dans certains modèles pour fournir la contribution nécessaire à l'accélération du vent solaire "rapide", voire pour chauffer la couronne solaire. Elle est souvent associée, dans ces modèles, à une cascade turbulente d'ondes d'Alfvén, dont les ondes cyclotroniques ioniques constituent la limite haute-fréquence. Ces modèles s'appuient en particulier sur certaines caractéristiques des distributions cinétiques ioniques observées dans la haute couronne (par spectroscopie) et dans le vent solaire (mesures in situ), telles que chauffage préférentiel en fonction du rapport charge-sur-masse (q/m), anisotropies de températures, ou vitesses différentielles. <br />L'objet principal de cette thèse consiste à mettre en évidence des signatures d'ondes d'Alfvén et d'ondes cyclotroniques dans la basse couronne solaire (<1.5 rayons solaires), dans l'intention de mieux contraindre l'énergie réellement présente sous forme d'ondes, et celle effectivement dissipée dans la couronne. <br />Pour cela, j'ai utilisé les largeurs des raies coronales appartenant à des ions de différents q/m, observées à l'aide du spectromètre SUMER opérant dans l'extrême-UV, et embarqué à bord du satellite SOHO. J'ai séparé les deux principales contributions à ces largeurs : effets Doppler thermique et "non-thermique" (lequel est potentiellement dû à la présence d'ondes d'Alfvén), en analysant le gradient des largeurs en fonction de l'altitude au dessus du limbe solaire. Lors de ce travail, j'ai montré l'importance de corriger les profils de raies observés de l'effet de la lumière diffusée instrumentale. <br />J'ai mis en évidence deux signatures de chauffage préférentiel dans un trou coronal : les ions de plus petits q/m sont plus chauds que les autres à une altitude donnée, et ils sont davantage chauffés quand l'altitude augmente. Par ailleurs, les courbes de températures en fonction de q/m présentent une tendance similaire dans un trou coronal et dans une région de "soleil calme", ce qui laisse penser que la résonance cyclotronique ionique se produit à toutes les latitudes. <br />Ces résultats me permettent de suggérer quelques pistes pour la modélisation des échanges entre ondes, ions minoritaires et protons.

With device scaling, the current optical lithography technique is reaching its technological limit to print small features. Extreme Ultra-Violet (EUV) lithography has shown promise to print extremely thin lines reliably and cost-effectively. Many challenges remain before introducing EUV to large scale manufacturing. The main challenge addressed in this study is particle removal from EUV mask surfaces (CrON1, CrON2, and fused silica) and thermal oxide (SiO₂). Effective pre-clean procedures were developed for each surface. As chemical cleaning methods fail to meet SEMATECH criteria, addition of megasonic energy to EUV mask cleaning baths is seen as a promising cleaning methodology. As the requirement to print fine lines needs to be met, all materials used in EUV mask fabrication either absorb the incident EUV wavelength light or reflect it. Therefore, the masks used in the industry will be reflective instead of the conventional transmissive masks. Also, for the same reason, no protective pellicle can be used leading to all the surfaces unprotected from particle contamination. To avoid the detrimental effect of the particle contamination, a cleaning study for nano-particle removal was performed. A dark field microscope was utilized to study the removal of gold nano-particles from surfaces. The cleaning procedures utilized H₂SO₄ and NH₄OH chemistries with and without megasonic irradiation. The cleaning variables were bath concentration, temperature, and megasonic power. The contamination variables were the gold nanoparticles charge and size, from 40nm to 100nm. For 100 nm negatively charged gold nano-particles deposited on a CrON1 surface, a 1:10 H₂SO₄:DI bath at boiling temperature (101°C) without megasonics gave high particle removal efficiency (PRE) values as did a 1:10 H₂SO₄:DI bath at 35°C with 100W megasonics. Comparison of removal of poly diallyl-dimethyl ammonium chloride (PDAC) coated and uncoated gold nano-particles deposited on a CrON1 surface using dilute H₂SO₄ baths indicated that the coated, positively charged nano-particles were more difficult to remove. PRE trends for different baths indicate surface dissolution (shown to be thermodynamically favorable) as the particle removal mechanism. However, experimental etch rates indicated minimal surface etching in a 10 minute bath. Increased surface roughness indicated possible local galvanic corrosion at particle sites. Low surface etching results meet SEMATECH requirements. During the fused silica surface cleaning study, particle charge (negative) and size (100 nm) of the contamination source and cleaning bath chemistry (NH₄OH) were kept constant. Low PREs were obtained at room temperature for all NH₄OH bath concentrations; however, high PREs were obtained at an elevated temperature (78°C) without megasonics and at room temperature in more dilute chemistries with megasonic power applied. Similar PRE trends were demonstrated for thermal SiO₂ surfaces. The experimental etch rates of the thermal SiO₂ agree with published values.

L'élaboration de nouveaux revêtements interférentiels multicouches est motivée par la demande de l'astrophysique solaire et par le développement de nouvelles sources de rayons EUV (source à génération d'harmoniques d'ordre élevé, laser X, rayonnement synchrotron). Nous avons étudié et développé différents systèmes multicouches possédant à la fois des propriétés optiques optimisées (réflectivité et/ou bande passante) et une bonne stabilité temporelle et thermique pour la gamme de longueurs d'onde comprise entre l=30 nm et l=50 nm. Des multicouches destinées à la sélection d'harmonique ont été optimisées et utilisées pour la réalisation d'un interféromètre EUV. Une augmentation significative de la réflectivité des multicouches dans la gamme spectrale de 30 à 40 nm a été obtenue par l'addition d'un troisième matériau dans l'empilement. Une étude comparative des courbes de réflectivités théorique et expérimentale en fonction de la longueur d'onde a été menée. Les différences observées ont pu être expliquées notamment à l'aide de l'analyse des propriétés physique des différents matériaux en couche mince. Nous montrons également que l'utilisation de ces multicouches à trois matériaux par période permet le développement d'empilements répondant à des demandes spécifiques (miroirs à large bande passante, miroirs à double bande). Pour les longueurs d'ondes comprises entre 35 nm et 50 nm nous avons développé des multicouches à base de scandium. Cette étude a permis d'obtenir des multicouches avec de forts pouvoirs réflecteurs et une bonne stabilité temporelle. La stabilité de ces empilements a pu être améliorer à l'aide de l'insertion aux interfaces de couches barrières

The chemical reaction of the first excited electronic state of molecular nitrogen, N₂(A), with ground state atomic oxygen is an important contributor to thermospheric nitric oxide (NO).  The importance is assessed by including this reaction in a one-dimensional photochemical model.  The method is to scale the photoelectron impact ionization rate of molecular nitrogen by a Gaussian centered near 100 km. Large uncertainties remain in the temperature dependence and branching ratios of many reactions important to NO production and loss. Similarly large uncertainties are present in the solar soft x-ray irradiance, known to be the fundamental driver of the low-latitude NO.  To illustrate, it is shown that the equatorial, midday NO density measured by the Student Nitric Oxide Explorer (SNOE) satellite near the Solar Cycle 23 maximum can be recovered by the model to within the 20% measurement uncertainties using two rather different but equally reasonable chemical schemes, each with their own solar soft-xray irradiance parameterizations.  Including the N₂(A) changes the NO production rate by an average of 11%, but the NO density changes by a much larger 44%.  This is explained by tracing the direct, indirect, and catalytic contributions of N₂(A) to NO, finding them to contribute 40%, 33%, and 27% respectively. The contribution of N₂(A) relative to the total NO production and loss is assessed by tracing both back to their origins in the primary photoabsorption and photoelectron impact processes.  The photoelectron impact ionization of N₂ is shown to be the main driver of the midday NO production while the photoelectron impact dissociation of N₂ is the main NO destroyer.  The net photoelectron impact excitation rate of N₂, which is responsible for the N₂(A) production, is larger than the ionization and dissociation rates and thus potentially very important.   Although the conservative assumptions regarding the level-specific NO yield from the N₂(A)+O reaction results in N₂(A) being a somewhat minor contributor, N₂(A) production is found to be the most efficient producer of NO among the thermospheric energy deposition processes. / Ph. D.

Laser high-order harmonic generation in the presence of relatively weak interfering light is investigated. The interfering pulses intersect the primary harmonic-generating laser pulse at the laser focus. The interfering light creates a standing intensity and phase modulation on the field, which disrupts microscopic phase matching and shuts down local high harmonic production. Suppression of the 23rd harmonic (by two orders of magnitude) is observed when a counter-propagating interfering pulse of light is introduced. A sequence of counter-propagating pulses can be used to shut down harmonic production in out-of-phase zones of the generating volume to achieve quasi phase matching. Harmonic emission is enhanced in this case. A new high-power laser system with higher pulse energy has been constructed to further investigate quasi phase matching of high-order harmonics generated in difficult-to-ionize atomic gases (e.g., neon as opposed to argon). The new system can also be used to study harmonic generation in ions. A new counter-propagating beam produces a train of 5 pulses with regulated timing. In preliminary tests, the new system has produced high harmonics up to the 65th order in neon. This should increase with additional adjustments to the laser system. The high-order harmonics have also demonstrated to be useful for polarized reflectometry measurements of optical surfaces in the extreme ultraviolet (EUV) wavelength range.

Extreme ultraviolet lithography(EUVL) is being developed worldwide as the next generation technology to be inserted in ~ 2009 for the mass production of IC chips with feature sizes <35 nm. One major challenge to its implementation is the development of a 13.5 nm EUV source of radiation that meets the requirements of current roadmap designs of the source of illumination in commercial EUVL scanners. The light source must be debris-free, in a free-space environment with the imaging EUV optics that must provide sufficient, narrow spectral band EUV power to print 100 wafers/hr. To meet this need, extensive studies on emission from a laser plasma source utilizing tin-doped droplet target was conducted. Presented in this work, are the many optical techniques such as spectroscopy, radiometry, and imaging, that were employed to characterize and optimize emission from the laser plasma source State of the art EUV spectrographs were employed to observe the source's spectrum under various laser irradiation conditions. Comparing the experimental spectra to those from theory, has allowed the determination of the Sn ion stages responsible for emitting into the useful EUV bandwidth. Experimental results were compared to spectral simulations obtained using Collisional-Radiative Equilibrium (CRE) model, as well. Moreover, extensive measurements surveying source emission from 2 nm to 30 nm, which is the region of the electromagnetic spectrum defined as EUV, was accomplished. Absolutely calibrated metrology was employed with the Flying Circus instrument from which the source's conversion efficiency (CE)--from laser to the useful EUV energy--was characterized under various laser irradiation conditions. Hydrodynamic simulations of the plasma expansion together with the CRE model predicted the condition at which optimum conversion could be attained. The condition was demonstrated experimentally, with the highest CE to be slightly above 2%, which is the highest value among all EUV source contenders. In addition to laser intensity, the CE was found to depend on the laser wavelength. For better understanding, this observation is compared to results from simulations. Through a novel approach in imaging, the size of the plasma was characterized by recording images of the plasma within a narrow band, around 13.5 nm. The size, approximately 100 ìm, is safely within the etendue limit set by the optical elements in the EUV scanner. Finally, the notion of irradiating the target with multiple laser beams was explored for the possibility of improving the source's conversion efficiency.