Generation of 30-50 nm structures using easily fabricated, composite PDMS masks

This communication demonstrates an approach to generate simple nanostructures with critical dimensions down to 30 nm over cm2-sized areas using composite PDMS masks. These masks were patterned with feature sizes down to 100 nm. When used in phase-shifting lithography, these masks generated arrays of structures in photoresist with line widths as small as 30 nm, slots in metal with features down to 40 nm, and wells in epoxy with diameters as small as 100 nm. The wells were used to prepare arrays of uniformly sized nanocrystals of salts.