Can surface roughness impact extreme ultraviolet lithography? This paper reports the observation of speckle patterns in EUV imaging, addressing concerns about light scattering and flare in EUV lithography. The study investigates the impact of light scattered by multilayer-coated EUV optics on image quality. Experiments using a Schwarzchild objective-based EUV microscope reveal high contrast speckle patterns in the scattered halo around the specularly reflected beam. Simulations indicate that the speckle effect is not likely to cause significant image degradation if current design goals for sub-0.5 nm roughness on mirror surfaces are met. The finding suggests that the stringent surface roughness specifications for EUV lithography systems are justified. This research contributes to the broader understanding of optics and lithography, potentially influencing the design and fabrication of future EUV systems.
Since `journal_categories` are empty, it's hard to contextualize. Returning an empty string for `journal_context` field.