Fabrication of three-dimensional high-aspect-ratio structures by oblique-incidence Talbot lithography

TL;DR

This paper introduces a novel UV lithography method leveraging multi-wave interference via oblique-incidence Talbot effect to create high-aspect-ratio 3D nanostructures suitable for mass production.

Contribution

It proposes a unique UV exposure technique controlling incident angles to generate multi-wave interference, enabling fabrication of sub-wavelength high-aspect-ratio nanostructures.

Findings

Finite-difference time-domain simulations confirmed sub-wavelength fringe patterns.

Successfully fabricated structures with aspect ratio of 30 over large areas.

Demonstrated potential for scalable mass production of 3D nanostructures.

Abstract

Developing a suitable production method for three-dimensional periodic nanostructures with high aspect ratios is a subject of growing interest. For mass production, Talbot lithography offers many advantages. However, one disadvantage is that the minimum period of the light intensity distribution is limited by the period of the diffraction grating used. To enhance the aspect ratio of fabricated nanostructures, in the present study we focus on multi-wave interference between diffracted waves created using the Talbot effect. We propose a unique exposure method to generate multi-wave interference between adjacent diffraction orders by controlling the angle of incidence of an ultraviolet (UV) light source. Using finite-difference time-domain simulations, we obtain fringe patterns with a sub-wavelength period using a one-dimensional periodic grating mask. Moreover, we demonstrate the practical application of this approach by using UV lithography to fabricate sub-wavelength periodic structures with an aspect ratio of 30 in millimeter-scale areas, indicating its suitability for mass production.