Diffraction in proximity x-ray lithography: Comparing theory and experiment for gratings, lines, and spaces

Abstract

We investigated diffraction effects in proximity x-ray lithography, at λ = 1.3 nm, by imaging lines, spaces, and gratings of nominal 0.2, 0.3, 0.4, and 0.5 μm-width at gaps, G, that varied from 5 to 100 μm in each exposure. For the smallest features, 0.17 μm spaces and 0.23 μm lines, process latitude and image quality were reduced for G ≥ 18 μm, though the features printed for gaps of up to 35 μm. Linewidth oscillations with gap, predicted from Fresnel calculations with Kirchhoff boundary conditions, were not detected in the experiment.