Roll-to-roll nanoimprinting is expected to overcome many scalability limitations of current batch imprint techniques, including production of large imprint areas, high throughput patterning, and lower cost. There is a significant potential for creating engineered surfaces using the roll-to-roll method, which could lead to new products, such as wire-grid polarizers, anti-reflective surfaces, and nanogratings for novel color filters for use in displays. In this Scalable NanoManufacturing (SNM) project, this potential will be demonstrated by manufacturing metasurfaces which are ultrathin nanostructured films that are capable of exhibiting ultra-efficient light control and are known to find significant use in optical communication, information processing, laser systems, and to improve the efficiency of liquid crystal displays. To develop this roll-to-roll imprinting method, the project team will pursue research that involves several disciplines of science and engineering including roll-to-roll transport of flexible materials, roller nanoimprint lithography, process modeling and simulation, and structure characterization. Furthermore, this award will provide research opportunities for undergraduates, minority students, high school teachers and students and incorporate research results into undergraduate and graduate curricula. Throughout the project, the research team will collaborate on relevant technical topics with practicing engineers and scientists from industry.
This award will focus on scaling up nanoimprint lithography using ultraviolet cured resins in a roll-to-roll process to produce multilayer devices with large areas through repetitive coating and imprinting on a moving substrate. The technical challenges include determining suitable resin materials and films, uniform roll-to-roll transport of the film through the imprinting process, mold filling, process modeling and control systems to facilitate high throughput transport, metrology and inspection. The research is unique in integrating the resin characteristics, coating and imprinting processes, dynamics of roll-to-roll transport machinery with metrology into a control algorithm. This algorithm will control process and machine parameters to maintain imprint quality inferred by metrology. The goal is to improve the speed and the resolution of the current roll-to-roll nanoimprinting process and to extend the process to actual photonic device fabrication. The research team will achieve this goal by combining their expertise in modeling and simulation, material and process development and characterization, and collaboration with industry. An example is the imprint contact mechanics will induce web tension change and result in slippage/shearing of imprinted features as the web exits the imprint roller. By combining expertise of resin characteristics during curing with contact mechanics and tension control the slippage and distortion of the imprinted features can be minimized.
