Le collage direct est maintenant utilisé par un nombre croissant d'applications en microélectronique (Elaboration de SOI, technologie imager Back Side Illumination, technologies 3D...). C'est une technique d'assemblage permettant de coller deux surfaces sans apport de matière adhésive. Principalement utilisée pour le collage de wafers, elle vient en complément de techniques telles que l'épitaxie ou le dépôt de couches minces. Ce collage s'effectue sous certaines conditions : il faut que les surfaces soient suffisamment propres, planes et lisses pour qu'il y ait une adhésion spontanée à température et pression ambiante. Enfin, un traitement thermique est appliqué pour augmenter l'énergie d'adhérence. Pendant le processus de fabrication, il peut apparaître des défauts de collage qui sont essentiellement dus à un piégeage de particules. Ces défauts se présentent sous la forme de bulles d'air. Finalement, les défauts de collage et l'énergie de collage sont les deux caractéristiques à partir desquelles est déduite une qualité de collage.Aujourd'hui, la technique utilisée pour la mesure d'énergie de collage est le clivage au coin. C'est une technique qui consiste dans un premier temps à séparer partiellement deux wafers par une lame, et dans un second temps, à calculer l'énergie de collage à partir d'une équation comportementale qui intègre la longueur de décollement. Mis à part le fait qu'elle permette la mesure d'énergie seulement sur quelques points, il se trouve que c'est une technique destructive. Un contrôle non destructif serait très intéressant pour l'industrie microélectronique et spécialement pour les lignes d'inspection. De plus, les procédés de fabrication microélectronique n'étant pas uniforme, avoir la possibilité d'obtenir une cartographie d'énergie de collage serait un atout majeur. A ce jour, aucune technique respectant ces deux exigences n'est connue. L'objectif de cette étude est d'utiliser la microscopie acoustique pour mesurer l'énergie de collage.Dans cette étude, un modèle inspiré de la "méthode des matrices hybrides" a été développé afin de modéliser des collages de différentes qualités. Le résultat de la modélisation montrera que le coefficient de réflexion acoustique de la structure collée est influencé par la qualité d'interface. En se plaçant dans des conditions précises, une méthode expérimentale est alors réalisée pour la mesure de la qualité d'interface. En parallèle, des wafers de Silicium réalisés par collage direct ont été spécialement conçus pour valider la méthode. Sur ce principe, des cartographies bidimensionnelles d'énergie de collage sont réalisées.Dans un second temps, la technique est améliorée afin d'augmenter la résolution latérale. Pour cela, un transducteur ayant une lentille est utilisé pour focalisé les ondes ultrasonores en points du collage. Une étude théorique est tout d'abord menée en utilisant le modèle du "spectre angulaire" afin de simuler la diffraction par la lentille. Enfin, des cartographies expérimentales confirmeront la faisabilité de mesures d'énergie de collage hautes résolutions. / Direct bonding is used for many applications in microelectronics (SOI Silicon-On-Insulator technology, imager back side illumination technology, 3D technology...). It is a processes that consists in an assembly of two surfaces without any adhesive material. It is primarily used to bond silicon wafers and it is complementary with other microelectronics technique such as epitaxy, thin film deposition... Bonding requires special wafer surface conditions and preparations. The surfaces have to be clean, flat and smooth to obtain a spontaneous adhesion at ambient temperature and atmospheric pressure. A heat treatment is applied to increase the adherence energy. During the manufacturing process, bonding defects may appear which are due to trapping of particles. These bonding defects are essentially formed of air. Finally, bonding defects and bonding energy are the two main characteristics from which is deduced the bonding quality.Nowadays, the main technique that is used to measure the direct bonding energy is the double cantilever beam (DCB). The method consists in firstly partially separating the two wafers by a blade, and secondly calculating the bonding energy from an equation that integrates the debonding lenght. The major disadvantage of this technique is its destructiveness. Furthermore it is only possible to make measurements on few points.Thus a non-destructive characterisation could be very interesting especially for an industrial in-line inspection. Moreover, having the possibility to obtain a mapping of the bonding energy could lead to interesting development. Up to know, no technique can reach the both requirements. The aim of this work is to use the acoustic microscopy to measure the direct bonding energy.In this study, a model based on "hybrid matrix method" has been developed to model bonding with different qualities. The results of the modelling show that the acoustic reflection coefficient of the bonded structure is influenced by the quality of the interface. From these results, an experimental method is proposed to perform quality of the interface measurements from the reflection coefficients acquired under normal incidence. In parallel, silicon wafers have been bonded to validate the method. Finally, once the method validated, two-dimensional mappings of the interface quality are realised.Secondly, the technique is improved to increase the lateral resolution. For this, a transducer having a lens is used to focus the ultrasonic waves on the bonded structure. A theoretical study is conducted using the model of the "angular spectrum" to simulate the diffraction lens. Finally, experimental mapping confirm the feasibility of measuring bonding energy of high resolutions.

Le collage par adhérence moléculaire consiste à joindre deux surfaces entre elles sans l'utilisation de matière adhésive. Cette technologie est particulièrement utilisée pour la fabrication de systèmes optiques comme les découpeurs d'images ou les interféromètres qui sont utilisés en optique terrestre. L'objectif final dans le développement de cette technologie est d'intégrer ces assemblages dans des systèmes optiques spatiaux. Or l'environnement spatial est totalement différent de l'environnement terrestre. Un satellite peut subir des chocs, des vibrations ou de la fatigue thermique. Il est nécessaire de caractériser avec précision l'adhérence moléculaire sous ces sollicitations pour respecter les exigences de l'Agence Spatiale Européenne. Cette thèse s'attache à caractériser la tenue aux chocs de l'adhérence moléculaire. Dans ce contexte, une nouvelle machine d'essais a été développée pour mener une campagne d'essais. Ce nouveau banc d'essais consiste à générer un choc dans une éprouvette placée dans un système de type Arcan. Les premiers essais sont réalisés sur des assemblages en aluminium collé avec trois différentes colles afin de valider le comportement du banc d'essais. Puis, une campagne expérimentale est effectuée sur des éprouvettes en verre de silice adhérées par adhérence moléculaire avec différentes procédures de traitement de l'adhérence. L'énergie de rupture aux chocs est définie pour chaque type d'interface avec les essais dynamiques. Suite aux essais statique, une simulation par éléments finis permet de définir la contrainte critique à l'aide d'un critère en contrainte. Pour finir, une étude de choc sur un Coin de Cube optique est réalisée. / The fused silica glass direct bonding consists in joining two surfaces without using any adhesive. This technology is used in particular to manufacture optical systems like optical slicers or interferometers used in terrestrial optics. The final aim in the development of this technology is to integrate these assemblies in spatial optics systems. However the spatial environment is totally different from the terrestrial one. A satellite may undergo shocks, vibrations or thermal fatigue. It is necessary to characterize with accuracy the direct bonded interface under these solicitations to respect the European Space Agency requirements. The aim in this works consists to characterize the direct bonding shock resistance. In this context, a new test machine has been developed to lead on an experimental campaign. This new machine design consists to generate a shock in a specimen placed in modified Arcan device. The first tests are performed on adhesively-bonded assemblies in aluminium with three different adhesives to validate the bench behaviour. After, an experimental campaign is performed on silica glass direct bonding samples with different bonded procedure. The shock fracture energy is defined for each type of interface with dynamic tests. Following static tests, a simulation by finite elements is used to define the critical stress with a stress criterion. To finish, a shock study on a representative structure, in our case a Corner cube optic, is performed.

Dans les modules de puissance à connexion filaire de type wire-bonding (WB), les forts courants commutés (jusqu’à 200A pour une puce de 10x10mm²) imposent de faibles résistances et inductances d’interconnexion pour réduire la chute de tension et les surtensions. Pour cette raison, les concepteurs multiplient les fils de bonding de grand diamètre (jusqu’à 500μm) en parallèle. De plus, quand la surface de puce le permet, les WB sont soudés à au moins deux endroits différents pour améliorer la distribution du courant. A la différence d’un assemblage standard de type WB, dans un module de puissance de type Direct-Lead-Bonding (DLB), la puce et la diode sont généralement brasées d’un côté, via la technique du flip-chip, sur le dissipateur intégré. L’autre face est brasée ou frittée directement sur une broche (ou clip) interne large pour former la maille électrique grâce à une brasure à base d'étain, d’argent et de cuivre (SAC ou Sn-Ag-Cu), très épaisse pour éviter le claquage broche-terminaison de puce. Par conséquent, le DLB peut offrir une surface de contact plus performante sur les plans électrique et thermique que le WB, réduisant ainsi la résistance de contact d’environ 50% selon la bibliographie (d’un facteur dix selon nos simulations électromagnétiques), améliorant la distribution du courant dans les puces et homogénéisant la température au sein du composant. De plus, l’inductance parasite interne peut être atténuée de 57% comparé au WB selon la littérature. Si l’on aborde la dimension sécuritaire, la tenue en surintensité ou I²T d’un module de puissance WB rempli de gel de silicone est faible et procure un effet fusible naturel bien qu’imparfait (mode de défaut circuit-ouvert). Les fils de bonding subissent un phénomène de soulèvement même si leur design n’a pas été pensé dans ce sens. En remplaçant le gel par de la résine époxy, ce comportement se dégrade pour donner un mode de défaut intermédiaire dû à la limitation en température de la résine. A l’inverse, le DLB devrait montrer un très fort I²T et donc, un mode de défaut se rapprochant du court-circuit. Ces travaux proposent une approche innovante sur le thème du design des topologies de conversion sécurisées à tolérance de panne : pourquoi ne pas construire une topologie autour du mode de défaillance intrinsèque d’un module de puissance, au lieu de mettre en place des moyens classiques pour le contrecarrer, i.e. essayer d'isoler systématiquement le défaut avec des fusibles ? Le module de puissance DLB était le candidat idéal pour mettre à l’œuvre notre philosophie. Dans un premier temps, nous avons cherché à comparer les modes de défaillance des deux technologies, WB et DLB, grâce à des essais destructifs d’énergies maîtrisés. Les résistances de défaut, énergies critiques et I²T ont été mesurées sur un banc dédié, de même que des analyses d'endommagements des zones de défaillance ont été réalisées au sein du CNES-THALES Lab de Toulouse par une méthode non intrusive de type Lock-In-Thermography (LIT). Il a été montré que la technologie DLB pouvait présenter une résistance de défaut dix fois plus faible que celle de la technologie WB à même surface de puce et à même énergie de destruction. La présence du clip permet aussi de réduire le gradient thermique dans la région du défaut et de moins contraindre thermiquement l'encapsulant par rapport à la technologie WB. La forte épaisseur du joint de brasure broche – puce garantit aussi une meilleure métallisation par refusion de la zone de perçage et ainsi une résistance de défaut plus faible. Dans un second temps, les modules détruits WB et DLB ont subi des essais d’endurance sur 5 semaines, afin d’éprouver la robustesse et la stabilité de leur résistance de défaut à faible et fort courants. Les résultats montrent clairement la supériorité de la technologie DLB. Par la suite, une campagne de caractérisation thermique (Rth/Zth) des deux technologies WB et DLB a été réalisée sur la base d'un banc développé à cet effet. / In wire-bonding (WB) power-modules, high current commutated by fast power chips (up to 200A on a 10x10mm² chip) implies low resistance and low stray inductance interconnections in order to reduce voltage drop and overvoltage. For this purpose, designers use numerous large-diameter bonding wires (up to 500μm) in parallel. Whenever the die surface is large enough (like IGBTs), bonding wires are soldered at least in two different spots to improve current distribution. Compared to conventional WB structure, inside Direct-Lead-Bonding (DLB) power-modules, chip and diode are generally soldered on one side, using flip-chip method, to the heat spreader. The other side is directly soldered or sintered to the large inner lead (or clip) to form the electrical loop with a thick standard SAC soldering (Sn-Ag-Cu) in order to avoid electrical breakdown between chip and clip. Therefore, DLB would provide a wider bonding area than WB design, reducing the emitter contact resistance by almost 50% in the literature (by a factor of 10 according to our simulation results), improving current uniformity in the chips and thus resulting in a uniform surface temperature distribution inside the device. Besides, DLB internal inductance could be reduced to 57% of wire-bonded modules according to literature. Considering safety aspects, the overcurrent capability of a gel-filled wire-bonding power module is low and provides a natural but imperfect wire-fuse-effect (as an open-failure mode). Lift-offs happen even if WB design is not optimized for it. Replacing the gel with an epoxy resin, this behaviour gets worse and an intermediate failure-mode is reached due to the epoxy temperature limitation. On the opposite, DLB should have a very high overcurrent capability characteristic and thus short-failure mode behaviour. This work offers a quite new approach in the field of fault-tolerant structure design: what if we use the faulty power module in a new way, instead of getting rid of it using classic methods to disconnect it, i.e. systematically isolating the power device using fuses? The DLB power module was the perfect candidate to experience our philosophy. In the first place, a comparison of both technologies has been performed through post-fault-behaviour characterisation using controlled energy failure tests. Post-fault resistances, critical energies and overcurrent capability have been measured on a dedicated test-bench, along with defect localization and analysis through micro-section thanks to the CNES-THALES Lab in Toulouse, using non-intrusive Lock-In Thermography (LIT) method. Failed DLB power-modules have showed post-fault resistances 10 times lower than wire-bonded power-modules with the same die size and the same destruction energy. The clip also reduces temperature gradient around the defect location and thus, releases the resin’s thermal constraints compared to WB technology. The very thick solder joint between clip and chip ensures a better metallic reforming and therefore a less resistive post-fault resistance. In the second place, faulty power modules under low and high destruction energy, both WB and DLB, have been tested during 5 weeks for durability and robustness. Results clearly show DLB supremacy. Then, a long campaign of thermal characterization of both designs (Rth/Zth) has been carried out thanks to another dedicated bench. We have proposed a new heating technique setting the die in its linear mode, which avoids using a high current power supply. We have modelled both designs using COMSOL Multiphysics in order for them to be simulated and compared in terms of thermal resistance and impedance, electrical resistance and inductance. The DLB thermal diffuser effect has been analysed. Thermal resistances are very similar (~0,13°C/W) meanwhile, surprisingly, WB is better than DLB in terms of thermal impedance with a maximum difference of 20% at 0.1s.

The thesis entitled “Unravelling the Nature of Halogen and Chalcogen Intermolecular Interactions by Charge Density Analysis" consists of five chapters. A basic introductory section describes the topics relevant to the work and the methods and techniques utilized. The main focus of the present work is to characterize the interaction patterns devoid of strong classical hydrogen bonds. The case studies include halogen bonds and hydrogen bonds involving bromine (as a halogen bond donor and hydrogen bond acceptor), intermolecular chalcogen bond formation involving sulphur, type I Br Br contacts, type II F F and F S interactions and S-H S hydrogen bonds. Chapter 1 discusses experimental and theoretical charge density analyses on 2,2-dibromo-2,3-dihydroinden-1-one which has been carried out to quantify the topological features of a short C Br···O halogen bond with nearly linear geometry (2.922Å, C Br···O=172.7) and to assess the strength of the interactions using the topological features of the electron density. The electrostatic potential map indicates the presence of the “- hole” on bromine while the interaction energy is comparable to that of a moderate O-H O hydrogen bond. In addition, the energetic contribution of C-H···Br interaction is demonstrated to be on par with that of the C-Br···O halogen bond in stabilizing the crystal structure. Chapter 2 discusses an organic solid, 4,7-dibromo-5,6-dinitro-2,1,3-benzothiadiazole that has been designed to serve as an illustrative example to quantitatively evaluate the relative merits of halogen and chalcogen bonding in terms of charge density features. The compound displays two polymorphic modifications, one crystall zing in a non-centrosymmetric space group (Z =1) and the other in a centrosymmetric space group with two molecules in the asymmetric unit (=2). Topological analysis based on QTAIM clearly brings out the dominance of chalcogen bond over the halogen bond along with an indication that halogen bonds are more directional compared to chalcogen bonds. The cohesive energies calculated with the absence of both strong and weak hydrogen bonds as well as stacking interaction are indicative of the stabilities associated with the polymorphic forms. Chapter 3 discusses the role of a type I C-Br Br-C contact and what drives the contact i.e. how a dispersive interaction is stabilized by the remaining contacts in the structure. In the process we observe the role the Br2Cl motif which is quite unique in its nature. Also the role of the bromine atoms in stabilizing the stacking interactions has been shown by the electrostatic potentials which are oriented perpendicular to the plane of the benzene ring. Chapter 4 discusses the enigmatic type II C-F F-C and C-FS-C interactions in pentafluorophenyl 2,2- bithiazole. Both the interactions are shown to be realistic “-hole” interactions based on high resolution X-ray charge density analysis. As fluorine is the most electronegative element, its participation in halogen bonding wherein the electrostatic potential around the atom gets redistributed to form regions of electron depletion and accumulation had time and again been speculated but never observed. In this chapter the experimental charge dnsity analysis clearly identifies the “-hole” on fluorine and distinguishes the C-F S-C interaction as a halogen bond rather than the chalcogen bond. Chapter 5 discusses the experimental charge density analysis of the hitherto unexplored S-H S hydrogen bond in crystal structures. The work highlights how relatively small is the number of crystal structures which are constructed by the S-H S hydrogen bond compared to the X-H S hydrogen bond via Cambridge Structural Database (CSD) analysis. The potential S-H S hydrogen bond is studied in three isomeric mercaptobenzoic acids with experimental charge density collected on 2-mercaptobenzoic acid and theoretical estimates made on 3- and 4-mercaptobenzoic acid. The strength and directionality of the S-H S hydrogen bond is demonstrated to be mainly due to the conformation locking potential of intramolecular S O halogen bond.

L'adhérence moléculaire est une technique d’assemblage basée sur la mise en contact directe de deux surfaces sans utiliser aucune colle ou produit spécifique à l’interface. Une telle opération nécessite que les surfaces à coller soient suffisamment lisses et qu’elles soient suffisamment rapprochées pour provoquer l’adhérence moléculaire. La caractérisation de la tenue mécanique de ce type d’assemblage par des essais mécaniques classiques de type pelage, clivage ou double cisaillement présentent des dispersions de mesures très importantes.Le premier objectif de ce travail concerne la conception et le développement d’un nouvel essai pour l’analyse de l’amorçage de fissure permettant d’obtenir des résultats moins dispersés que les essais classiques notamment pour des colles fragiles de faible épaisseur comme l’adhésion moléculaire. Seul le mode I a été étudié et un montage de type DCB modifié a été proposé pour étudier l’amorçage pour différentes géométries de bord (homogène, concentration de contrainte élevée, …).Le second objectif se propose, en partant des différents résultats expérimentaux obtenues, de comparer des approches (PSC, CC, MZC) qui permettent de prédire l’amorçage de la fissure pour des colles fragiles et en particulier pour l’adhérence moléculaire. L’idée est de proposer une solution simple aux ingénieurs souhaitant prédire la rupture dans un assemblage collé avec une épaisseur de colle tendant vers zéro. / Direct bonding by molecular adhesion is a bonding technique based on joining two surfaces into direct contact without the use of any adhesives or additional material. Such an operation requires the surfaces that are to be bonded to be sufficiently smooth and for them to be sufficiently close together to allow contact to be initiated. Mechanical characterization of this type of assembly with classical mechanical test as for instance wedge test, cleavage test or double shear test present a highly defects sensitivity on mechanical results.The first objective of this work concerns the design and the development of a new test for the analysis of crack initiation in order to obtain results less dispersed than conventional tests particularly for fragile adhesives with small thickness as molecular bonding. Only the mode I was investigated and an experimental device based on modified DBC classical test is proposed to study crack initiation with different edge geometries (homogeneous, high stress concentration).The second objective proposed, in starting from the different experimental results obtained, to compare some approaches (PSC, CC, MZC) to predict crack initiation for fragile adhesives and in particular for molecular bonding. The idea is to propose a simple methodology for engineers in order to predict fracture in an assembly bonded with an adhesive thickness close to zero.

In recent years supramolecular chemistry has established as one of the most active fields of science. The most significant feature of supramolecular chemistry is the use of building blocks which reversibly held together by intermolecular forces, electrostatic or H-bonding. Therefore, the synthesis of supramolecular systems using different non-covalent assemblies provides some unique architectures and features which are extremely difficult to be obtained via covalent synthesis. One main application of such influencing supramolecular systems is the preparation of self-healing materials. Among various approaches to self-healing effects, reversible bond formation has become prominent in the last years. To achieve both acceptable mechanical performance and self-healing behaviour from a polymeric material, proper balance between covalent and non-covalent bonding is important. The covalent bonding gives a basic strength to the material while the non-covalent bonding generates self-healing effects in the case of damage. The main aim of this study was to synthesize an organic moiety which is capable of forming supramolecular assemblies in the presence of suitable counterparts, followed by its incorporation on to polymer matrix and investigation of the final properties. For reversible bond forming technique H-bonding is exploited in this work. 4-substituted-2,6-diaminopyridine is selected as the organic moiety as it has a clear DAD (donor-acceptor-donor) structure and thus able to undergo self-association or triple hydrogen bonded complex formation with respective counterparts. Chichibabin reaction was utilised for the synthesis and 4-hydroxy-2,6-diamido pyridine was synthesised as the key compound. Initially different derivatives of 4-hydroxy-2,6 diamino pyridine was synthesized and utilised towards the formation of supramolecular network with a suitable monomeric counterpart. Poly (butadiene-co-maleic anhydride) is used as the base polymer as it has the possibility to introduce non-covalent bonding sites through grafting reactions on the double bonds or on maleic anhydride groups. The free amine group present in the main compound was grafted onto the backbone of poly (butadiene-co-maleic anhydride) via reaction of amine with maleic anhydride group. The main design of supramolecular self-assembly within poly (butadiene-co-maleic anhydride) with a suitable counterpart poly (butadiene-co-maleimide), is prepared and used in this thesis. The miscibility of the two polymers is proven by the presence of a single Tg in the DSC results of the mixture and also by the formation of homogeneous films with no phase separation in AFM. However the formation of hydrogen bonding within the monomer was proven by 1H NMR, IR studies. Further formation of complex between two polymers was established from the results of viscosity. Also the interactions between the complexes exert a distinct influence on the rheological behavior of the blend. Lastly the reversibility of this supramolecular blend was assured by temperature dependent viscosity values. In the final part of this work, bromobutyl rubber (BIIR) is selected as the model elastomer which has vast application in the tire industry; as the inner-liner that holds the air in the tire and also used as rubber stoppers for sealing medicine vials and bottles The bromine functionality can be substituted with an amine group making it more susceptible towards the incorporation of different organic moieties. In this way, the derivative of 2,6-diaminopyridine having a pendant amine group is incorporated in BIIR. As a counterpart uracil is used as its H-bond forming ability with diaminopyridine moieties is well established and supported by different previous research works. The supramolecular network formed between these two monomers help to generate self-healing effects within BIIR rubber. Fig. 2 represents the supramolecular network formed between chains of BIIR. The self-healing effect of the rubber material is examined through the stress-strain experiments where up to 82% healing was observed when heated up to 70 °C. With increasing temperature better healing was observed whereas at room temperature a 40% healing tendency was noticed. It is also interesting to note that the thermal and dynamic mechanical properties of this tailor made self-healing BIIR is identical with sulphur cured conventional BIIR.

L’étude de ce mémoire concerne l’élaboration d'un alliage alternatif sans plomb pour l’électronique de puissance, celui-ci sera utilisé à des fins de brasures. Les brasures actuelles sont composées d’alliages comportant du plombet sont peu résistantes en cas de travail à haute température. Ces systèmes seront progressivement éliminés, ils ne respectent plus la Directive Européenne sur l’environnement (RoHS) et les normes de santé publique en raison de la toxicité du plomb (cancérogène, mutagène, accumulation dans l’environnement …). Le travail a été réalisé avec l’alliage Ag-Sn, l’objectif principal de cette thèse a été d’élaborer le composé Ag3Sn, en raison de sa grande résistance thermique (température de fusion élevée de 480°C). Ses meilleures performances sont avantageuses pour les brasures situées dans des environnements difficiles comme l’aéronautique ou l’automobile. La première partie de ce manuscrit détaille la synthèse du composé Ag3Sn réalisée via la méthode polyol, une voie de chimie douce. Il s’agit d’une technique différente des techniques classiques, comme la voie métallurgique. La synthèse a été réalisée en plusieurs étapes et une méthode d’approches successives a été utilisée afin de déterminer les paramètres de synthèse optimums.Deux protocoles particuliers se détachent et ils permettent d’élaborer des phases résistantes à haute température. Lepremier permet d’élaborer une phase pure d' Ag3Sn, tandis que le second permet d’élaborer deux phases de solutionssolides. Les composés ont été caractérisés par DRX, par imagerie MEB-FEG et MET et par analyse thermogravimétrique.La seconde partie de ce travail est la consolidation de ce composé Ag3Sn par une technique de frittage particulière :le die-bonding, afin de réaliser la connexion entre la puce électronique et un susbtrat de cuivre recouvert d'argent.Une étape de dépôt des poudres sur le substrat a été nécessaire avant de réaliser la consolidation, elle a été réalisée selon différentes techniques : le spin-coating ou le dépôt par sérigraphie. Puis, les paramètres de frittage par die-bonding ont été affinés selon les techniques de dépôt. Enfin, des essais de cisaillement ont été réalisés sur certains échantillons. / The study of this memoir concerns the development of an alternative lead-free alloy for power electronics, which will be used for solders. Nowadays, current solders are composed of alloys containing lead, and aren't resistant at high work temperature. These systems will be phased out, because they no longer comply with the European RoHS Directive and public health standards due to the toxicity of lead (carcinogenic, mutagenic, accumulation in the environment, etc.). This work was carried out with the Ag-Sn alloy, and the main objective was to develop the elaboration of the Ag3Sn compound, due to its high thermal resistance (high melting point of 480°C). Its best performance is an advantage for solders located in difficult work environments such as aeronautics or automobile. First part of this thesis describes the synthesis of Ag3Sn compound with the polyol process, a soft-chemistry routine. It is different from the conventional techniques, like the metallurgical way. Polyol synthesis was realized by following several steps. A method of successive approaches wasdetermine optimum synthesis parameters. Two specific protocols stand out, and they allow the development of high-temperature resistant phases. The first one allows the elaboration of an Ag3Sn pure phase, an the second one allows the development of two compounds of solid solutions. The compounds were characterized by XRD, FEG-SEM, TEM and thermogravimetric analysis. The second part of this work is the consolidation of the Ag3Sn compound with a special sintering technique : the die-bonding, in order to realize the connexion between the electronic chip and the copper substrate coated silver. A first step of depositing powder on the substrate was necessary before carrying out the implementation. It was carried out with various techniques : spin-coating orthe serigraphy deposition. Then, sintering parameters were refined according to the deposition techniques. Finally, shear tests were performed on different samples

The thesis is aimed at perinatal factors affecting the emotional bond between a mother and a child (boding) during the first weeks postpartum. The literature review is divided into three chapters. The first chapter discusses the childbirth, the experience of childbirth and the factors affecting a subjective evaluation of the childbirth by a parturient. The second chapter follows up with an overview of findings concerning the initial afterbirth moments, and the interaction between a mother and a child during early contact. The third chapter introduces the concept of bonding. It describes its manifestations, possible measuring methods, and factors influencing its quality. The research part analyzes perinatal factors affecting bonding on a sample of 1108 mothers with the use of generalized linear regression. The independent variables are: mode of birth, the evaluation of childbirth experience by mother, and the process of early contact between a mother and a child. The results show that bonding during the first weeks postpartum was not affected by the mode of birth or by the parturient's evaluation of the childbirth experience. A significant effect was found in the occurrence of early contact between a mother and a child; mothers who had contact with the child during the first postpartum hour reported...

Indiana University-Purdue University Indianapolis (IUPUI) / Since their introduction in 1970, glass ionomer cements have been used in a wide variety of clinical situations in dentistry. The main advantages of glass ionomer cements are chemical bonding, fluoride release and uptake, excellent seal against microleakage, and biocompatibility. The main objective of this study was to compare the microleakage of two new paste-paste glass ionomer systems to their traditional RMGIC counterparts when conditioning the dentin with newly developed no-rinse conditioners or polyacrylic acid. Materials and methods: Standardized cavity preparations were made, centered on the cementoenamel junction of the buccal surface, on 96 extracted human molars divided in 8 groups (n = 12). G1 Ketac Nano with Ketac Nano Primer, G2 Ketac Nano with Ketac Conditioner, G3 Photac Fil with Ketac Nano Primer, G4 Photac Fil with Ketac Cavity Conditioner, G5 Fuji Filling LC with GC Self Conditioner, G6 Fuji Filling LC with GC Cavity Conditioner, G7 Fuji II LC with GC Self Conditioner, G8 Fuji II LC with GC Cavity Conditioner. The cavities were treated with either a no-rinse or polyacrylic acid conditioner and restored with a paste-paste RMGIC or traditional RMGIC from the same manufacturer (n =12). The teeth were then sealed to within 2 mm of the restoration margins and thermocycled. The teeth were immersed in 2.0-percent methylene blue and stored at room temperature for 24 hours. Then, the teeth were be embedded in resin and sectioned longitudinally in a buccolingual direction making 1 section (1 mm thick) per tooth. The occlusal and gingival restoration margins of each specimen were examined with a stereomicroscope at X10 magnification to determine the degree of microleakage. Results: Mixed-model ANOVA was used to test the fixed effect of the eight groups and cervical vs. occlusal location within each tooth sample on microleakage, with sample as the random effect. Both main effects and the interaction are significant, p < 0001 for both group and location effects, and p = 0.0013 for the interaction of group and location. The cervical interface showed more microleakage in all groups except group 8 where microleakage was the same as at the occlusal margin. No significant difference was observed among groups for microleakage at the occlusal interface. There was significant difference among groups at the cervical interface with Fuji II LC using GC Cavity Conditioner performing best. For the occlusal interface Group 4 performed the best and Group 2 performed the worst, although the difference was not significant among the groups. For the cervical interface, Group 8 performed the best followed by Group 3, Group 4 and Group 6, although these four groups were not significantly different. For the cervical interface, group 2 performed the worst followed by group 1. Based on these results we can conclude that, overall, traditional RMGIC with polyacrylic acid conditioning performed better than the new paste-paste RMGIC systems utilizing the no-rinse conditioners.

Electrostatic interactions such as halogen bonding and pnictogen bonding interactions have gained a lot of interest in the field of crystal engineering and pharmaceutical science. In the first part of this thesis, we expand our knowledge on anion coordinated halogen bonded cocrystals by looking at a series of cocrystals made from 3-iodoethynyl pyridine and 3-iodoethynylbenzoic acid. We utilize the power of mechanochemistry to create the new cocrystals made with phosphonium salts and use multinuclear solid-state nuclear magnetic resonance spectroscopy and X-ray diffraction and characterize them. We found that mechanochemistry is a fast and powerful tool to explore and synthesize new halogen bonded cocrystals and ³¹P solid-state NMR is a rapid way to identify the formation of a cocrystal. In the second part, we look at the versatility of the pnictogen atom, specifically antimony, as a pnictogen bond donor and a halogen bond acceptor. We evaluate these electrostatic interactions with nuclear quadrupolar resonance and found that nuclear quadrupole resonance is a strong spectroscopy tool to probe these types of electrostatic interactions.