Demonstrating 30-nm spatial resolution of three-multilayer-mirror objective for extreme ultraviolet microscopy: Imaging test by observing lithography mask

To confirm the high spatial resolution expected in extreme ultraviolet (EUV) microscopy, fine grating patterns with a half-pitch of less than 100 nm on a lithography mask were imaged using a full-field microscope based on a multilayer-mirror objective. When the tilted illumination technique is applied to this novel imaging system, a spatial resolution better than 20 nm can be expected at a wavelength of 13.5 nm. We demonstrated high resolution via EUV reflection images of test patterns with a half-pitch between 30 and 80 nm.