EUV Dark‐Field Microscopy for Defect Inspection

Abstract

An actinic EUV microscope for defect detection on mask blanks for operation in dark field using a table‐top discharge‐produced plasma source has been developed. Several test structures (pits and bumps) on multilayer mirrors were investigated by our Schwarzschild objective‐based EUV microscope at 13.5‐nm wavelength and then characterized with an atomic force microscope. Possible defect‐detection limits with large field of view and moderate magnification are discussed in terms of required irradiation dose and system performance.