Double-exposure lithography has shown promise as potential resolu- tion enhancement technique that is attractive because it is much cheaper than double-patterning lithography and it can be deployed on existing imaging tools. However, this technology is not possible without the development of new materials with nonlinear response to exposure dose. Several materials have been proposed to implement a nonlinear response to exposure including re- versible contrast enhancement layers (rCELs), two-photon materials, interme- diate state two-photon (ISTP) materials, and optical threshold layers (OTLs). The performance of these materials in double-exposure applications was inves- tigated through computer simulation using a custom simulator. The results from the feasibility studies revealed that the ISTP and OTL types of materials showed much more promise than the rCEL and two-photon types of materi- als. Calculations show that two-photon materials will not be feasible unless achievable laser peak power in exposure tools can be signi¯cantly increased. Although rCEL materials demonstrated nonlinear behavior in double-exposure mode, only marginal image quality and process window improvements were ob- served. Using the results from the simulation work described herein, materials development work is currently ongoing to enable potential ISTP and OTL materials for manufacturing. A new biochip platform named \Mesoscale Unaddressed Functional- ized Features INdexed by Shape" (MUFFINS) was developed in the Willson Research Group at the University of Texas at Austin as a potential method to achieve a new low-cost biosensor system. The platform uses poly(ethylene glycol) hydrogels with bioprobes covalently cross-linked into the matrix for detection. Each sensor is shape-encoded with a unique pattern such that the information of the sensor is associated with the pattern and not its position. Large quantities of individual sensors can be produced separately and then self- assembled to form random arrays. Detection occurs through hybridization of the probes with °uorescently labeled targets. The key designs of the system include parallel batch fabrication using photolithography and self-assembly, in- creased information density using multiplexing, and enhanced shape-encoding with automated pattern recognition. The development of two aspects of the platform { self-assembly mechanics and pattern recognition algorithm, and a demonstration of all the key design elements using a single array are described herein. / text

The field of organic chemistry is divided into many subfields, which include polymer design and synthesis, transition metal catalysis and organocatalysis among a variety of others. Challenges in polymer design and synthesis can be highlighted pointedly in the use of photoresists for lithographic processing. Recent challenges in development of shorter wavelength sources has led to the need to develop new photoresist materials that can be exposed twice without any development steps in between. Two methods for addressing double exposure materials will be presented. Additionally, the areas of catalysis, whether transition metal or organic in nature, are important methods in organic synthesis. The mechanism of the addition of Gilman reagents to enones has been the subject of debate, and efforts to elucidate this mechanism will be presented. Finally, organocatalysis has expanded its scope into a variety of reactions previously only conducted with transition metal catalysts. Work towards an enantioselective allylic amination reaction using organocatalysis as well as absolute stereochemistry of the product will be explored. / text

The relentless commercial drive for smaller, faster, and cheaper semi-conductor devices has pushed the existing patterning technologies to their limits. Photolithography, one of the crucial processes that determine the feature size in a microchip, is currently facing this challenge. The immaturity of next generation lithography (NGL) technology, particularly EUV, forces the semiconductor industry to explore new processing technologies that can extend the use of the existing lithographic method (i.e. ArF lithography) to enable production beyond the 32 nm node. Two new resolution enhancement techniques, double exposure lithography (DEL) and pitch division lithography (PDL), were proposed that could extend the resolution capability of the current lithography tools. This thesis describes the material and process development for these two techniques. DEL technique requires two exposure passes in a single lithographic cycle. The first exposure is performed with a mask that has a relaxed pitch, and the mask is then shifted by half pitch and re-used for the second exposure. The resolution of the resulting pattern on the wafer is doubled with respect to the features on the mask. This technique can be enabled with a type of material that functions as optical threshold layer (OTL). The key requirements for materials to be useful for OTL are a photoinduced isothermal phase transition and permeance modulation with reverse capabilities. A number of materials were designed and tested based on long alkyl side chain crystalline polymers that bear azobenzene pendant groups on the main chain. The target copolymers were synthesized and fully characterized. A proof-of-concept for the OTL design was successfully demonstrated with a series of customized analytical techniques. PDL technique doubles the line density of a grating mask with only a single exposure and is fully compatible with current lithography tools. Thus, this technique is capable of extending the resolution limit of the current ArF lithography without increasing the cost-of-ownership. Pitch division with a single exposure is accomplished by a dual-tone photoresist. This thesis presents a novel method to enable a dual-tone behavior by addition of a photobase generator (PBG) into a conventional resist formulation. The PBG was optimized to function as an exposure-dependent base quencher, which mainly neutralizes the acid generated in high dose regions but has only a minor influence in low dose regions. The resulting acid concentration profile is a parabola-like function of exposure dose, and only the medium exposure dose produces a sufficient amount of acid to switch the resist solubility. This acid response is exploited to produce pitch division patterns by creating a set of negative-tone lines in the overexposed regions in addition to the conventional positive-tone lines. A number of PBGs were synthesized and characterized, and their decomposition rate constants were studied using various techniques. Simulations were carried out to assess the feasibility of pitch division lithography. It was concluded that pitch division lithography is advantageous when the process aggressiveness factor k₁ is below 0.27. Finally, lithography evaluations of these dual-tone resists demonstrated a proof-of-concept for pitch division lithography with 45 nm pitch divided line and space patterns for a k₁ of 0.13. / text