High throughput roller type nano-pattern transfer technique on both rigid flexible substrates and mold deformation analysis under atmospheric imprint environment

This paper provides a roller type nano-pattern transfer process, which is based on UV nanoimprint lithography, for nano-patterning on both rigid and flexible substrates. By using UV-curable polymer resist, room temperature and low pressure process, which is possible to apply to flexible films, is introduced. PDMS and PVA soft molds that can have conformal contact with large area non-flat substrate surface are fabricated. The nano-scale mold patterns are duplicated from Si wafer after E-beam lithography and DRIE dry etching. A homemade roller type printing machine with an elastic buffer layer is designed and fabricated to achieve uniform printing results over entire working area. High-throughput printing process with printing speed up to 50 mm/s is demonstrated. Glass, Si wafer and PET film were tested as printing substrates. Micro and nano-patterns were transferred clearly to the polymer layer on substrates. Images from optical microscope, SEM and AFM were used to evaluate the transferred nano-patterns. Detail process flow, including mold fabrication, is described. The governing parameters in the process are discussed. Simulation and theoretical analysis on the mold deformation under atmosphere imprint environment is studied. The effect of surface property during the pattern transfer process is identified.