Qualitative Assessment of the UV Exposition Process Near the Diffraction Limits

Abstract

Optical lithography is one of the most common microfabrication methods. A major limitation of photolithography is a diffraction phenomenon, which affects the falsities in dimensions and shape of designed structures, due to the light bending on the mask edges. In the presented work, the technological parameters that influence the shape of the resist structures are reported. The experimental results are compared with the simulations results, based on the solution of Maxwell’s equations using the RF module of COMSOL Multiphysics software. The electric field intensity distribution in the resist layer was analysed for the mask slits that are larger and comparable to the applied wavelength. The differences in wave energy absorption in the resist layer are presented and discussed. For both cases, the impact of the chromium film thickness of the mask on the pattern profile of the resist is studied, and the comparison is performed between the simulation and experimental results.