Influence of symmetry and duty cycles on the pattern generation in achromatic Talbot lithography

Achromatic Talbot lithography has been proved as a robust and high throughput technique for large area nanopatterning with controllable feature sizes and duty cycles. In this work, the influence of symmetry and duty cycles on the pattern generation has been investigated in detail. Compared with square lattice case, no lattice rotation and spatial frequency multiplication can be observed in hexagonal nanopattern generation. Uniform pattern distribution with a 20 nm feature size has been obtained in square and hexagonal lattices by the masks with 144 nm period and similar to 50% duty cycle. For the exposure of mask with a smaller duty cycle, nonuniform dot size distribution has been obtained in the square lattice. While, by using a smaller duty cycle hexagonal lattice mask, a highly uniform periodic hexagonal nanopattern with a 10% duty cycle has been obtained. All the experimental results were consistent with the simulation work. (C) 2017 American Vacuum Society.