The potential of a cascaded grating interferometer to perform Extreme Ultraviolet Interference Lithography (EUV-IL) depends on its beng coupled to a source that is bright enought to allow exposures ina reasonable time. This work presents a graphicat 2D approach that provides insight into the operation of the interferometer and simple graphical estimates for the effects of source divergence and wavefront curvature on the depth of field. A more rigorous, analytic 3D treadtment improves on these estimates and also treats the possible loss of fringe contrast due to grating misalignment and period mismatch. The results are applied to illustrate the feasibility of implementing the interferometer on a small bending magnet synchrotron source.
Citation: Applied Optics
Pub Type: Journals
interference lithography, Helmholtz equation, diffraction gratings