Prospective wavelengths for projection lithography uing synchrotron radiation

Promising wavelengths for next-generation lithography with a wavelength shorter than 13.5 nm based on a synchrotron X-ray source are discussed. Theoretical and experimental values of the reflection coefficients of multilayer X-ray mirrors providing the maximum reflectivity in the range of 11.4–3.1 nm are presented. The theoretical efficiency of multilayer optics is compared for different wavelengths.