A photo-polymerization resist for UV nanoimprint lithography

A novel liquid photo-polymerization resist was prepared for nanoimprint lithography on transparent flexible plastic substrates. The resist is a mixture of polymethylmethacrylate (PMMA), methylmethacrylate (MMA), methacylic acid (MAA) and two photo-initiators, (2-isopropyl thioxanthone (ITX) and ethyl 4-(dimethylamino)benzoate (EDAB)). The resist can be imprinted at room temperature with a pressure of 0.25 kg/cm2, and then exposed from the transparent substrate side using a broad band UV lamp to obtain nano- and micro-scale patterns. Replications of high-density line and space patterns with resolution of 150 nm were obtained on a flexible indium tin oxide/poly(ethylene terephthalate) (ITO/PET) substrate. The liquid resist has low viscosity due to the liquid monomers, and low shrinkage due to the addition of PMMA as a binder.