All-inorganic thermal nanoimprint process

The authors describe a nanoimprint method for an all-inorganic resist material, aluminum oxide phosphate. The resist is free of organic additives, water-based, environmentally benign and yields dense, amorphous, crack-, and pore-free films after annealing at 300 °C. They achieved macroscopically defect-free imprinted areas of up to 25 cm2, using flexible ethylene tetrafluoroethylene imprint molds. It is shown that, if temperature and pressure are chosen such that the residual solvent in the resist stays liquid during imprinting, macroscopically defect-free imprints can be obtained. Volumetric shrinkage due to postimprint annealing is characterized. The imprinting tests are performed on standard thermal nanoimprint equipment, but the process is believed to be scalable for large-area imprinting.