Theoretical simulated fabrication of nanostructure by interference of four-beam guided mode excited by 193 nm laser

This study proposed a lithography method for fabricating periodic nanostructures using the interference of four-beam TE0 guided modes excited by a 193 nm deep ultraviolet laser. The physical mechanism and normalized electric field intensity distribution of four-beam TE0 guided mode interference were theoretically analyzed and numerically simulated using the finite element method. The simulation results confirmed the ability of this method to fabricate periodic structures with a half-pitch resolution of 30.35 nm (approximately ?/6.36), an aspect ratio of 3.95, and a contrast ratio of 1. The theoretically calculated value of the resolution was consistent with the numerical simulation value. The resolution and aspect ratio of the fabricated nanostructures could be adjusted through changes to the thickness of the resist. Moreover, the shape of the fabricated nanostructures, such as the one-dimensional sub-wavelength grating structure and two-dimensional square array lattice structure, were adjustable via changes to the number and azimuth of the excited TE0 guided modes. The results obtained in this study provide valuable theoretical information for the practical manufacture of ultra-high-resolution lithography.