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Sub-micron patterning is fundamental to the fabrication of numerous devices Traditional commercial manufacturing methods either lack the resolution needed to attain the appropriate size or are prohibitively expensive due to low throughput or the necessity of expensive equipment. Imprint lithography is a rapid, inexpensive alternative to making sub-micron features that can be tailored to work with a variety of materials. Imprint lithography, while traditionally used with pure polymers has been tailored to be used with nanoparticle-polymer hybrid films. This work has achieved high-fidelity pattern transfer onto polymer-nanoparticle hybrid films with feature sizes as small as 250 nm. The polymer-nanoparticle hybrid was fabricated by creating a liquid suspension of functionalized ZnO nanoparticles and poly(methyl methacrylate) (PMMA) in a solvent. The ZnO particles were functionalized by adding nonanoic acid in order to facilitate the dispersion of the particles in a non-polar solvent. This suspension was spread onto substrate, imprinted with a patterned stamp, allowed to dry, and was demolded. The final result was features ranging from 250 nm to 1 μm in size with good fidelity as determined by the accuracy of the feature replication and the surface roughness of the overall sample. The effect of the ZnO content as well as the method of combining the suspension components on the feature fidelity was studied. In general, it was found that feature fidelity is acceptable up to a dry-film composition of 15 vol% ZnO and that feature sizes above 500 nm were more tolerant of higher solids loading. The same imprint lithography method was also used to pattern a polymer-derived SiOC glass. The SiOC was shown to be have interesting shrinkage properties where the feature-level linear shrinkage was up to 5% more than that of the bulk. The features were shown to be stable during pyrolysis up to 1000°C and stable at operating temperatures up to 1000°C. A constant number Monte Carlo simulation was used to describe the suspension behavior to confirm the empirical results from the physical experiments. The effects of Van der Waals forces, steric stabilization, depletion flocculation, as well as the physical impediment of entangled polymer chains were considered. A similar agglomeration behavior was shown in the simulations compared to the physical experiments. This thesis shows that polymer-nanoparticle hybrid films are a compatible material for imprint lithography using appropriate suspension parameters. This is very important for a variety of applications and devices. Using imprint lithography to make these devices makes them cheaper and more accessible to the commercial market and can make a large number of theoretical devices a reality. / Ph. D. / Sub-micron patterning is an integral part of making many modern technologies such as memory storage devices or integrated circuits. As this technology becomes smaller and smaller, the limiting factor for making these devices has become the ability to manufacture effectively at the appropriate scale. Traditional commercial manufacturing methods lack the resolution needed to attain small enough features. Manufacturing methods that can make small enough features are often either extremely expensive or offer incomplete control of the feature morphology. Imprint lithography is a high-throughput, inexpensive alternative to making sub-micron features that can be tailored to work with a variety of materials. Imprint lithography is simple process in which a patterned stamp is pressed into a softened film of material in order to transfer the pattern of the stamp onto that material. Traditionally, imprint lithography works best with polymers and researchers have struggled to pattern nanoparticle-based materials. This work has achieved high-fidelity pattern transfer onto polymer-nanoparticle hybrid films with feature sizes on the same order as the polymer films found reported in literature. The polymer-nanoparticle hybrid was realized by creating a liquid suspension of functionalized ZnO nanoparticles and poly(methyl methacrylate) (PMMA) in a solvent. The ZnO particles were functionalized by adding nonanoic acid, allowing the normally polar particles to disperse in the non-polar solvent needed to dissolve the PMMA. This suspension was spread onto a glass substrate, imprinted with a patterned stamp, allowed to dry, and was demolded. The final result was the successful transfer of features ranging from 250 nm to 1 μm in size with good fidelity. The effect of the ZnO content as well as the method of combining the suspension components on the feature fidelity was studied. To help prove the broad applicability of this imprint method, it was adapted for use with polymer-derived ceramics. Additionally, a computer simulation was developed to help understand the behavior of the nanoparticle-polymer suspension during the imprint process.

This dissertation constitutes two major sections. In the first major section, a kinetic analysis was established to investigate the electromigration (EM), enhanced intermetallic compound (IMC) growth and void formation for Sn-based Pb-free solder joints to Cu under bump metallization (UBM). The model takes into account the interfacial intermetallic reaction, Cu-Sn interdiffusion, and current stressing. A new approach was developed to derive atomic diffusivities and effective charge numbers based on Simulated Annealing (SA) in conjunction with the kinetic model. The finite difference (FD) kinetic model based on this approach accurately predicted the intermetallic compound growth when compared to empirical observation. The ultimate electromigration failure of the solder joints was caused by extensive void formation at the intermetallic interface. The void formation mechanism was analyzed by modeling the vacancy transport under electromigration. The effects of current density and Cu diffusivity in Sn solder were also investigated with the kinetic model. The second major section describes the integration of Step and Flash Imprint Lithography (S-FIL®) into an industry standard Cu/low-k dual damascene process. The yield on a Back End Of the Line (BEOL) test vehicle that contains standard test structures such as via chains with 120 nm vias was established by electrical tests. S-FIL shows promise as a cost effective solution to patterning sub 45 nm features and is capable of simultaneously patterning two levels of interconnect structures, which provides a low cost BEOL process. The critical processing step in the integration is the reactive ion etching (RIE) process that transfers the multilevel patterns to the inter-level dielectrics (ILD). An in-situ, multistep etch process was developed that gives excellent pattern structures in two industry standard Chemical Vapor Deposited (CVD) low-k dielectrics. The etch process showed excellent pattern fidelity and a wide process window. Electrical testing was conducted on the test vehicle to show that this process renders high yield and consistent via resistance. Discussions of the failure behaviors that are characteristic to the use of S-FIL are provided. / text

" Because technology provides the tools and biology the problems, the two should enjoy a happy marriage ! "1 . Cette phrase resume parfaitement l'esprit du projet qui a motive ces travaux de these. En effet, le couplage des biotechnologies et des micro et nano technologies, resume sous le vocable < Nanobiotechnologies > est une activite en plein essor qui laisse presager de nombreuses applications en particulier dans le domaine de la biodetection. Lobjectif principal de ces travaux est dedie au developpement de strategies d'adressage de biomolecules a l'echelle nanometrique pour des applications de biodetection. Le premier aspect de ce travail est d'ordre technologique. Il concerne la fabrication de dispositifs d'adressage bases sur des reseaux de nanoelectrodes planaires. En utilisant un procede reposant sur lutilisation de la lithographie electronique haute resolution sur un microscope TEM/STEM, nous avons pu demontrer la fabrication de dispositifs a base de nanoelectrodes presentant des espaces inter-electrodes controlables entre 100 et 15nm. Une technique de lithographie alternative, la Nano-Impression est egalement presentee comme une solution possible a la replication de nanodispositifs fabriques par lithographie electronique. La deuxieme partie des travaux est dediee a la mise en place dun schema de detection de nanoparticules que nous avons developpe autour de dispositifs bases sur des reseaux delectrodes inter-digitees. Avant de nous interesser a l'utilisation de ces dispositifs pour une application biologique, nous avons etudie leur reponse electrique vis-a-vis de l'absorption de nanoparticules d'Or par interaction electrostatique. Les premiers resultats obtenus montrent que le schema de detection permet d'atteindre un niveau de sensibilite ultime au travers d'une mesure directe de la conductance des dispositifs. Certaines experiences montrent en effet la possibilite de mesurer electriquement l'adsorption d'une seule nanoparticule. Enfin, la derniere partie de ces travaux est dediee a l'adaptation de ce protocole pour la detection de biomolecules fonctionnalisees par des nanoparticules d'Or. Pour cela, nous avons employe une approche simple basee sur un systeme de reconnaissance entre une molecule cible et une molecule sonde. Ce schema a ete applique a la detection d'interaction antigene/anticorps et nous a permis de transcrire la selectivite de la reconnaissance entre les anticorps dans le depot des nanoparticules qui se traduit par une modification importante de la conductance du dispositif. Les possibilites d'integration ainsi que la compatibilite des dispositifs avec des systemes de microfluidique rendent ce schema de detection particulierement adapte pour le developpement d'un systeme integre de biodetection a tres haute sensibilite. 1 S. Fields, Proc. Natl. Acad. Sci. USA, vol 98, pp 10051-10054 (2001)

Springtails (Collembola) are wingless arthropods that are impressively adapted to cutaneous respiration in temporarily rain-flooded habitats by non-wetting skin morphology. Recapitulating the robust and effectively liquid-repellent surface characteristics of springtail skin in engineered materials may offer exciting opportunities for demanding applications. Herein, we present a strategy for mimicking morphological surface features of springtail skin in polymer membranes produced by reverse imprint lithography. We report the fabrication of multi-level silicon masters that, in turn, serve as templates for the replication of flexible polymer membranes. We examined the robust wetting characteristics of polymer membranes by in situ plastron collapse tests and condensation tests. The mechanical stability of the polymer membranes was tested using a tribometer set-up and compared with needle-shaped pillar structures made from similar material. The fabricated membranes are flexible, free-standing, and adaptable to various substrate materials and shapes that allow for emerging applications.

Springtails (Collembola) are wingless arthropods that are impressively adapted to cutaneous respiration in temporarily rain-flooded habitats by non-wetting skin morphology. Recapitulating the robust and effectively liquid-repellent surface characteristics of springtail skin in engineered materials may offer exciting opportunities for demanding applications. Herein, we present a strategy for mimicking morphological surface features of springtail skin in polymer membranes produced by reverse imprint lithography. We report the fabrication of multi-level silicon masters that, in turn, serve as templates for the replication of flexible polymer membranes. We examined the robust wetting characteristics of polymer membranes by in situ plastron collapse tests and condensation tests. The mechanical stability of the polymer membranes was tested using a tribometer set-up and compared with needle-shaped pillar structures made from similar material. The fabricated membranes are flexible, free-standing, and adaptable to various substrate materials and shapes that allow for emerging applications.