Développement et caractérisation des procédés de gravure plasma impliqués dans la réalisation de grille métallique de transistor pour les technologies FDSOI 14nm : contrôle dimensionnel et rugosité de bord

In a transistor manufacturing process, patterning is one of the hardest stages to control. Along with downscaling, the specifications for a transistor manufacturing have tightened up to the nanometer scale. Extreme metrology and process control are required and Critical Dimension Uniformity (CDU) and Line Width Roughness (LWR) have become two of the most important parameters to control.So far, to meet the requirements of the latest CMOS technologies, post-lithography treatments such as plasma cure treatments have been introduced to increase photo-resist stability and to improve LWR prior to pattern transfer. However, conventional post-lithography treatments are no more efficient to address the specifications of14nm gate patterning where more complicated designs are involved.In this work, we have studied limitations of cure pretreatments in 2D gate integrations. In fact, the HBr plasma post-lithography treatment was identified as being responsible of a local pattern shifting that result in a loss of the device’s electrical performance. Preliminary results show that, cure step removal helps to control pattern shifting but to the detriment of the LWR. Indeed, if no cure treatment is introduced in the gate patterning process flow, photoresist patterns undergo severe stress during the subsequent Si-ARC plasma etching in fluorocarbon based plasmas. In this work, the mechanisms that drive such resist degradation in fluorocarbon plasmas have been studied and improved SiARC etch process condition shave been proposed. Besides, we evaluate how the state-of-art gate etch process can be improved, by investigating the impact of each plasma etching step involved in the high-K metal gate patterning on both LWR and gate shifting. The goal of this study is to determine if the TiN metal gate roughness can be modified by changing the gate etch process conditions. Our research reveals that addition of N2 flash steps prevents from gate profile degradation and sidewall roughening. In revenge, the TiN microstructure as well as the HKMG etch process has no impact on the gate final roughness. The hard mask patterning process remains the main contributor for gate roughening.Dans le procédé d'élaboration d'un transistor, la définition des motifs de grilles est une des étapes les plus dures à contrôler. Avec la miniaturisation des dispositifs, les spécifications définies pour la structuration des transistors se sont resserrées jusqu'à l'échelle du nanomètre. Ainsi, le Contrôle Dimensionnel(CD) et la rugosité de bord des lignes (LWR) sont devenus les paramètres les plus importantes à contrôler. Précédemment, pour atteindre les objectifs définis pour les précédentes technologies CMOS, des traitements post-lithographiques tels que les traitements plasma à base d’HBr ont été introduits pour améliorer la résistance des résines aux plasmas de gravure et minimiser la rugosité des motifs de résine avant leur transfert dans l’empilement de grille. Cependant, ces méthodes conventionnelles ne sont plus satisfaisantes pour atteindre les spécifications des nœuds avancés 14FDSOI, qui font intervenir des schémas complexes d’intégration de motifs. Dans ces travaux, les limitations des traitements plasma HBr pour réaliser des motifs de grille bidimensionnels comme définis par les règles de dessin ont été mises en évidence. . En effet, il s’avère que les traitements par plasma HBr sont responsables d'un déplacement local du motif de grille, qui entraine sur le produit final une perte de rendement. Des résultats préliminaires montrent que le retrait de cette étape de traitement améliore le phénomène de décalage des grilles, au détriment de la rugosité des motifs de résines. En effet, les résines non traités par plasma subissent d’importantes contraintes lors de l’ étape de gravure SiARC en plasma fluorocarbonnés, ce qui génère une nette augmentation de la rugosité de la résine qui se transfère par la suite dans les couches actives du dispositif. Dans cette thèse, j’ai étudié les mécanismes de dégradation des résines dans des plasmas fluorocarbonés. Cette compréhension a abouti au développement d’une nouvelle chimie de gravure plasma de la couche de SiARC qui limite la dégradation des résines. De plus, j’ai évalué comment le procédé complet de gravure de grille métallique peut être amélioré pour éliminer la rugosité et la déformation des motifs en travaillant sur chacune des étapes impliquées. Le but de cette étude est d’identifier les étapes de gravure ayant un rôle dans la rugosité finale de la grille. Mes travaux montrent que l'ajout des étapes de nitruration limite la dégradation du profil de grille et de la rugosité des flancs. Au contraire, la microstructure du film de TiN ainsi que les procédés de gravure de grille métal n'ont pas d'impact sur la rugosité finale du dispositif. Le transfert du motif de grille lors des étapes de gravure du masque dur reste toujours le principal contributeur de la rugosité finale de grille

New approaches in optical lithography technology for subwavelength resolution

Advances in the semiconductor industry are mainly driven by improvements in optical lithography technology, which have enabled the continual shrinking of integrated circuit devices. However, optical lithography technology is approaching its limit, and within ten years, it may be substituted by new non-optical approaches. These may include Extreme Ultra Violet (EUV) lithography and charged particle beam projection lithography. While these technologies may have potentially better resolution, they can be very difficult to implement into manufacturing. During the course of the research presented here, the extension of optical lithography to sub 70nm resolution has been investigated. Since optical lithography is mature and well understood, extending it to allow for higher resolution can dramatically reduce manufacturing difficulties, compared to EUV or charged particle beam projection lithography. A majority of the existing infrastructure, such as photoresist materials, sources, optics, and photo-masks, remain applicable with the optical methods explored here. The avenues investigated in this research have concentrated on spatial frequency filtering in alternative Fourier Transform planes, vacuum UV wavelength lithography, and achieving ultra high numerical aperture imaging through the use of liquid immersion imaging. More specifically, novel spatial frequency filtering using angular transmission filters was developed and demonstrated. Multiple filter designs were proposed, one of which was successfully fabricated and implemented for lithographic imaging. Spatial filtering, using angular transmission filtering, proved to enhance the resolution of contact hole images by approximately 20%. Vacuum UV imaging at the 126nm wavelength was carried out but deemed likely to be less practical for commercial viability due to source, optics, and materials issues. Immersion lithography, using the 193nm wavelength ArF excimer laser, was investigated and demonstrated for very high numerical aperture imaging. Requirements for immersion lithography were established, including the necessary design of imaging fluids, optics, sources, and photoresist materials. As a development tool, an interference lithography system was built using the 193nm ArF excimer laser and water as an immersion fluid. Patterns below 70nm were printed using the process developed, which has established the potential to extend optical lithography further than was believed at the onset of this project. This research provides proof of the concept of extending optical lithography to the 70nm generation and below

Micro-machining techniques for the fabrication of fibre Fabry-Perot sensors

Fabry-Perot optical fibre sensors have been used extensively for measuring a variety of parameters such as strain, temperature, pressure and vibration. Conventional extrinsic fibre Fabry-Perot sensors are associated with problems such as calibration of the gauge length of each individual sensor, their relatively large size compared to the diameter of optical fibre and a manual manufacturing method that leads to poor reproducibility. Therefore, new designs and fabrication techniques for producing fibre Fabry-Perot sensors are required to address the problems of extrinsic fibre Fabry-Perot sensors. This thesis investigates hydrofluoric acid etching and F2-laser micro-machining of optical fibres to produce intrinsic Fabry-Perot cavities. Chemical etching of single mode fused silica fibres produced cavities across the core of the fibres due to preferential etching of the doped-region. Scanning electron microscope, interferometric surface profiler and CCD spectrometer studies showed that the optical quality of the etched cavities was adequate to produce Fabry-Perot interference. Controlled fusion splicing of etched fibres produced intrinsic Fabry-Perot cavities. These sensors were surface-mounted on composite coupons and their response to applied strain was studied using low coherence interferometry. These sensors showed linear and repeatable response with the strain measured by the electrical resistance strain gauges. To carry out F2-laser micro-machining of fused silica and sapphire substrates, a micro-machining station was designed and constructed. This involved the design of illumination optics for 157 nm laser beam delivery, the design and construction of beam delivery chamber, target alignment and monitoring systems. Ablation of fused silica and sapphire disks was carried out to determine ablation parameters suitable for micro-machining high aspect ratio microstructures that have adequate optical quality to produce Fabry-Perot interference. Cavities were micro-machined through the diameter of SMF 28 and SM 800 fibres at different energy densities. CCD interrogation of these intrinsic fibre cavities ablated at an energy density of 25 x 10 4 Jm -2 produced Fabry-Perot interference fringes. The feasibility of micro-machining high aspect ratio cavities at the cleaved end-face of the fused silica fibres and through the diameter of sapphire fibres was demonstrated. A technique based on in-situ laser-induced fluorescence monitoring was developed to determine the alignment of optical fibres and ablation depth during ablation through the fibre diameter. Ablation of cavities through the diameter of fibre Bragg gratings showed that the heat-generated inside the cavity during ablation had no effect on the peak reflection and the integrity of core and cladding of the fibre. Finally, a pH-sensor, a chemical sensor based on multiple cavities ablated in multimode fibres and a feasible design for pressure sensor fabrication based on ablated cavity in a single mode fibre were demonstrated.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

NASA SBIR abstracts of 1992, phase 1 projects

The objectives of 346 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1992 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 346, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1992 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included

Etude du dégazage des résines pour les lithographies électronique et extrême ultraviolet

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.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

Portland Daily Press: December 08,1880

https://digitalmaine.com/pdp_1880/1334/thumbnail.jp

The characteristics and feasibility of an in-line debris control technique for KrF excimer laser ablative micromachining

To observe KrF excimer laser ablation through thin liquid film of de-ionized (DI) water and the effects thereof on debris control, equipment was designed to contain a small control volume that could be supplied with a fixed flow velocity thin film of DI water to immerse a bisphenol A polycarbonate workpiece. Using the same equipment comparison with ablation in ambient air was possible. The positional debris deposition of samples machined in ambient air was found to show modal tendency reliant on the feature shape machined and according to species size. This is proposed to be due to the interaction of multiple shockwaves at the extent of ablation plumes generated at geometry specific locations in the feature. Debris was deposited where the shockwaves collide. Ablating under a flowing thin film of DI water showed potential to modify the end position and typical size of the debris produced, as well as increased homogeneity of deposition density. Compared with a sample machined in ambient air, the use of immersion has reduced the range of debris deposition by 17% and the deposition within the boundary of the ablation plume has a comparatively even population density. Unlike samples machined in ambient air, outside the ablation plume extents positional control of deposited debris by thin film flowing DI water immersion was evidenced by rippled flow line patterns, indicating the action of transport by fluid flow. A typical increase in debris size by an order of magnitude when using DI water as an immersing liquid was measured, a result that is in line with a colloidal interaction response... cont'd

On the Development of Praseodymium-Doped Radioluminescent Nanoparticles and Their Use In X-ray Mediated Photodynamic Therapy Of Glioblastoma Cells

Despite decades of research, few advancements have been made toward improving the prognosis of patients with glioblastoma, a lethal and invasive form of brain cancer. The current standard of care is fluorescence-guided surgical resection followed by radiotherapy and chemotherapy. Fluorescence guided surgery is performed using 5-aminolevulinic acid (5-ALA), a prodrug that induces the accumulation of fluorescent protoporphyrin IX (PPIX) in malignant cells. Conveniently, 5-ALA mediated production of PPIX is also renowned as the most popular photodynamic therapy (PDT) agent in the world. PDT is a treatment that uses visible light to stimulate a photosensitizer to produce reactive oxygen species, which can damage and kill cells. However, the technique is limited by the tissue depth penetration of light. The advent of nanomedicine has enabled the possibility to achieve PDT by using luminescent nanoparticles to alter the incident excitation source. When X-rays are used to excite the nanoparticles, the process is called X-ray mediated photodynamic therapy (X-PDT). Herein, we have developed NaLuF4:Pr3+ radioluminescent nanoparticles to achieve X-PDT. The emission spectrum of Pr3+ exhibits strong spectral overlap with the absorption spectrum of PPIX, an endogenous photosensitizer. A reproducible route to synthesizing uniform NaLuF4:Pr3+ nanoparticles at sizes relevant for cell uptake was developed, and the spectroscopic properties of the nanoparticles were evaluated prior to in vitro studies. The nanoparticles were found to exhibit persistent luminescence, and a mechanism was developed to explain the charge (de-)trapping process. The nanoparticle composition was optimized for excitation of PPIX and studied in the human glioblastoma cell line called U251. We evaluated the therapeutic effect of the nanoparticles with and without 5-ALA to establish the radiosensitization capability as well as the X-PDT effect. Three nanoparticle concentrations were studied using 4 radiation doses, including those relevant for intraoperative radiotherapy which is performed on the tumor cavity immediately after resection. The effects on stress, death, damage, senescence and proliferation were studied. and demonstrate promising results at a proof-of-concept level. Throughout this work, current clinical practice guided our experimental design, providing a strong foundation toward using Pr3+-doped nanoparticles for X-PDT in an intraoperative setting using endogenous PPIX as the photosensitizer