Sub-wavelength optical lithography via nanoscale polymer lens array

For the first time, under exposure is employed to fabricate the patterned photoresist templates with hemispherical cross-sectional profile. The long-range highly regular polymer lens array is replicated from the photoresist templates. The polymer lens array is utilized as the soft phase shift element to produce nearly perfectly periodic nanostructures with sub-100 nm feature size across centimeter-scale areas for the first time. The light focusing capabilities of the nanoscale polymer lens are verified by both simulation and experiment. The polymer lens arrays are repeated used for many times without obvious deterioration of their structures. By adjusting the size of polymer lens and the exposure dose, the metal and negative photoresist nanostructures with the smallest feature sizes of 80 and 200 nm are generated respectively. The advantages of this nanopatterning route lie in low-cost, high yield, long-range periodicity, programmable feature size, geometry and composition.