Theoretical studies of the electron scattering effect on developed pattern profiles in x-ray lithography

Abstract

Monte Carlo calculations of the photo and Auger electron production by a monochromatic x ray of Al Kα have been performed to study the effect of their diffusion in a 1.0-μm polymethyl methacrylate resist film on replicated patterns both with and without the Si substrate. Based on both the calculated spatial distribution of the absorbed energy density and the solubility rate for mixture developers of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA), investigations were carried out on the x-ray resist sensitivity, the ultimate resolution, and the mask contrast effect on developed profiles. Typically, the ultimate resolution was found to be 1000 Å with MIBK and to be 400 Å with MIBK : IPA=1 : 3. There was no significant influence of the Si substrate on the developed patterns.