X-ray Computed Tomography (CT) is a process that produces three-dimensional x-ray images, allowing for better diagnosis and analysis of complex internal medical conditions. New advances in the optical techniques used in this process promise to produce better results while reducing patient risk. One of these developments calls for precise optical gratings that can be expensive and difficult to manufacture. This paper presents a simple process developed specifically for the production of these gratings using cost effective techniques. The process uses well understood semiconductor fabrication steps including oxidation, deep reactive ion etching and electroplating. While not entirely successful, the process presented within provides a proof of concept for development of the gratings and discusses improvements that could be made to allow for success. / Master of Science

The microelectronics industry strives for continued reduction in feature sizes to allow increased computing speed and power. This calls for continuous development of new materials. During the shift to 157 nm photolithography, it was discovered that fluorinated materials were necessary to provide sufficient transparency. Material design and synthesis to incorporate fluorine bearing norbornane based materials through an alternate means of polymerization to those used in traditional lithographic materials will be presented. Step and Flash Imprint Lithography represents a low cost alternative to optical lithography for production of nanoscale features. Sub-20 nm features have been produced using commercial tools however the contact between the imprint template and resist formulation leaves the template prone to fouling. A new imprint resist designed to facilitate wafer reworking and template cleaning is presented. The small amount of power available from deep ultraviolet light sources necessitates the use of systems that behave in a catalytic manner that is referred to as gain. The use of small molecules for gain necessitates a reliance on diffusion through the resist film and results in image bias. A polymeric material that undergoes depropagation catalyzed by a single photochemical event and causes a solubility change due to this event represents a system that possesses gain while removing diffusion bias. Progress towards such a system is presented. / text

A novel process based on the principle of layered photolithography has been proposed and tested for making real three-dimensional micro-structures. An experimental setup was designed and built for doing experiments on this micro-fabrication process. An ultraviolet (UV) excimer laser at the wavelength of 248 nm was used as the light source and a single piece of photo-mask carrying a series of two dimensional (2D) patterns sliced from a three dimensional (3D) micro-part was employed for the photolithography process. The experiments were conducted on the solidification of liquid photopolymer from single layer to multiple layers. The single-layer photolithography experiments showed that certain photopolymers could be applied for the 3D micro-fabrication, and solid layers with sharp shapes could be formed from the liquid polymer identified. By using a unique alignment technique, multiple layers of photolithography was successfully realized for a micro-gear with features at 60 microns. Electroforming was also conducted for converting the photopolymer master to a metal cavity of the micro-gear, which proved that the process is feasible for micro-molding. / Singapore-MIT Alliance (SMA)

Photolithography is a key element of the modem integrated circuit process. It is photolithography, combined with metal deposition, that allows a three dimensional circuit to be built up on a two dimensional surface. Since it is such an important part of the semiconductor manufacturing industry, a massive base of research in this area already exists. The problem with this pre-existing research is that it is geared solely toward industrial purposes, as opposed to more academic research areas. The goal of my research is to move this industrial process into the academic setting of Pomom College.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 208-216). Available also in a digital version from Dissertation Abstracts.

Laser-based techniques have become essential tools for probing biological molecules in systems that demand high spatial and temporal control. This dissertation presents the development of micro-analytical techniques based on multiphoton excitation (MPE) to promote highly localized, three-dimensional (3D) photochemistry of biologically relevant molecules on submicron dimensions. Strategies based on capillary electrophoresis (CE) have been developed for the rapid separation and spectroscopic analysis of short-lived photochemical reaction products. High-speed separation and analysis are achieved through a combination of very high electric fields and a laser-based optical system that uses MPE for both the generation and detection of hydroxyindole photoproducts on the time scale of microseconds. MPE was also used for the development of photolithographic techniques for the creation of microstructured protein-based materials with highly defined three-dimensional (3D) topographies. Specifically, a multiphoton lithographic (MPL) technique was developed that used a low-cost microchip laser for the rapid prototyping of 3D microarchitectures when combined with dynamic optical masking. Furthermore, MPL was used to create novel “smart” biomaterials that reproducibly respond with tunable actuation to changes in the local chemical and thermal environment. The utility of these materials for creating biocompatible cellular microenvironments was demonstrated and presents a novel approach for studying small populations of microorganisms. Finally, through the development of a multifocal approach that used multiple laser beams to promote the photocrosslinking of biological molecules, the speed and versatility of MPL was extended to allow both the parallel fabrication of 3D microstructures and the rapid creation of large-scale biomaterials with highly defined spatial features. / text

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.Sc.). / Written for the Dept. of Chemistry. Title from title page of PDF (viewed 2009/06/29). Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2009. / Title from PDF title page (University of Texas Digital Repository, viewed on Aug. 6, 2009). Vita. Includes bibliographical references.

Thesis (M.E.)--University of Canterbury, 2007. / Typescript (photocopy). "March 2007." Includes bibliographical references (p. 123-127). Also available via the World Wide Web.