No description available.

Electron beam lithography (EBL) and Nanoimprint Lithography (NIL) are the promising tools for today’s technology in terms of resolution capability, fidelity and cost of operation. Achieving highest possible resolution is a key concept for EBL where there is a huge request in applications of nanotechnology for sub-20 nm feature sizes. Defining features at these length scales is a challenge, and there is a large demand for resist that is not only capable of giving high resolution but also having low cost and ease of process. In this work I studied Polystyrene (PS) which is an alternative organic e-beam resist in terms of ease of process and resolution capability. I examined the process of electron-beam exposure and attempted to characterize the factors that affect the achieved resolution and sensitivity. Besides this work, I designed and fabricated a new type of mold for NIL since mold fabrication is a key factor for NIL technology. The resolution of NIL process depends on the mold features and polymer mold technology received great attention in terms of cost of fabrication and process, fidelity, and reliability. I used MD 700 Fluoropolymer as a new type of polymer mold which was believed to be a good candidate for the polymer mold of high throughput NIL.

Electron beam lithography (EBL) and Nanoimprint Lithography (NIL) are the promising tools for today’s technology in terms of resolution capability, fidelity and cost of operation. Achieving highest possible resolution is a key concept for EBL where there is a huge request in applications of nanotechnology for sub-20 nm feature sizes. Defining features at these length scales is a challenge, and there is a large demand for resist that is not only capable of giving high resolution but also having low cost and ease of process. In this work I studied Polystyrene (PS) which is an alternative organic e-beam resist in terms of ease of process and resolution capability. I examined the process of electron-beam exposure and attempted to characterize the factors that affect the achieved resolution and sensitivity. Besides this work, I designed and fabricated a new type of mold for NIL since mold fabrication is a key factor for NIL technology. The resolution of NIL process depends on the mold features and polymer mold technology received great attention in terms of cost of fabrication and process, fidelity, and reliability. I used MD 700 Fluoropolymer as a new type of polymer mold which was believed to be a good candidate for the polymer mold of high throughput NIL.

Probe microscopy techniques (Atomic Force Microscopy and Kelvin Force Microscopy) have been shown to be instrumental in the analysis of samples; such as resists and nanostructured materials. Through these techniques detailed surface information has been derived, including information such as surface roughness and surface charge distribution. Poly(Methylmethacrylate) (PMMA), remains at the forefront of resists utilised in e-beam lithography in the electronics industry. Surface morphology (specifically roughness) analysis remains a key parameter of investigation, particularly in the examination of polymeric films. This research aimed to investigate PMMA based electron beam resists as well as a novel (SML) resist material in terms of suitability for electron-beam lithography. Various concentrations (5, 7, 8, 9 and 11% w/v) of both PMMA and the novel resist material were spin-coated onto silica substrates. Samples were baked at 180oC for 3 minutes and examined under ultra-high vacuum using Omicron AFM/SPM to derive RMS values in order to assess roughness in addition to thickness measurements taken. SML resists were then utilised in the development of a new digital etch onto InGaAs/InAlAs wafer. The novel, SML resist material was found to offer smoother resist surface even at higher concentrations of polymer, a difference which was observed to be statistically significant (p<0.01). The SML resist was also notably thicker than the comparable PMMA resist (p>0.05) indicating that lower concentrations of the novel resist would be required to achieve the required resist thickness. Digital etching rates were found to be in agreement with previously documented findings. SML was concluded to be a superior resist in terms of thickness and smoothness, with AFM being further established as an essential characterization technique.

It’s becoming more and more difficult to make smaller, denser, and faster computer chips. There’s an increasing demand to design new materials to be applied in current lithographic process to get higher patterning performance. In this work, the aqueous developable single molecule resists were introduced, synthesized and patterned. A new group of epoxide other than glycidyl ether, cyclohexene oxide was introduced to functionalize a molecular core and 15 nm resolution was obtained. The directed self-assembly (DSA) of block copolymers as an alternative lithographic technique has received growing interest in the last several years for performing higher levels of pitch subdivision. A 3-step simplified process for DSA by using a photodefinable substrate was introduced by using a functionalized polyphenol with an energy switchable group and a crosslinkable group. Two high χ block copolymers PS-b-PAA and PS-b-PHEMA were successfully designed and synthesized via ATRP with controlled Mw and PDI. The size of the same PS-b-PAA polymer was tunable by varying the thermal annealing time. PS-b-PHEMA shows to be a suitable block polymer for the industry-friendly thermal annealing process. A self-complementary hydrogen-bonding urea group as a center group was used to facilitate the self-assembly of polymers. “Click” chemistry is promising for synthesis of PS-Urea-Urea-PMMA.

L'objectif de ce travail est de développer et d'évaluer de nouvelles résines originales biosourcées pour l'application lithographique. Pour atteindre cet objectif, nous avons sélectionné différents types de lignine et étudié l'influence du fractionnement de la lignine sur les propriétés finales de la résine obtenue. Le fractionnement de la lignine est réalisé à l’aide de solvants organiques sélectionnés pour leur polarité. Nous avons choisi ce polymère naturel en raison de la présence de nombreux groupes fonctionnels directement responsables de sa réactivité : molécules photosensibles et potentiellement réticulables. La lignine est également une bonne candidate car abondante sur Terre et sa valorisation actuelle en tant que matière première chimique est négligeable. Nous avons étudié la photoréactivité de la résine à base de lignine à 395 nm en utilisant des sources de lumière LED. Sur la base des observations FTIR et UV-VIS, nous avons étudié et quantifié les changements structurels survenus lors de l'exposition de la photorésine à la lumière. Cependant, ces changements étaient plus intenses au cours de l'irradiation conduite dans l'air par rapport à une atmosphère inerte. De plus, nous avons établi le lien entre la structure chimique de la lignine et sa réactivité décrite par les tests de sensibilité, de contraste et de résolution. Nous avons proposé des mécanismes cohérents basés sur des données de la littérature. Ainsi, la réticulation de la lignine se produit sous les photons des rayonnements UV-VIS entraînant la formation de structures intermédiaires, de chromophores ou de composés volatils de bas poids moléculaire. Enfin, nous avons démontré qu'il était possible de fabriquer par écriture laser directe des nanostructures mono-, bi- et tridimensionnelles dans la photorésine à base de lignine "juste fractionnée" par polymérisation à deux photons. / The goal of this work was to develop and to evaluate new, original and bio-based resist for lithographic application. To reach this purpose, we have selected various types of lignin and study the influence of lignin fractionation in different organic solvents on the final resist properties. We have chosen this photosensitive and crosslinkable polymer due to its great abundance and to its currently poor valorisation as a chemical feedstock, as well as the versatility of the functional groups that were directly responsible for its reactivity. We have investigated the photoreactivity of lignin-based resist at 395 nm, using LED light sources. Based on the FTIR and UV-vis monitoring, we have investigated and quantified the structural changes occurred during photoresist exposure to the light. However, they were more visible during the irradiation conducted in the air than in the inert atmosphere. Moreover, we have established the link between chemical structure of lignin and its reactivity observed by sensitivity, contrast and resolution tests. Additionally, we have proposed reasonable mechanisms based on literature data according to which lignin crosslinking occur under UV-visible photons. They comprised the formation of intermediates structures, chromophores, or low molecular weight volatile compounds, as well and crosslinking reactions. Finally, we have demonstrated that it was possible to fabricate one-, two- and three-dimensional structures from "just-fractionated" lignin photoresist by two-photon polymerisation achieved by direct laser writing.