Defect inspection with an EUV microscope

An actinic EUV microscope for defect detection on mask blanks for operation in dark field using table top discharge produced plasma (DPP) source has been developed. Several test structures (pits and bumps) and natural defects on multilayer mirrors were characterized with an atomic force microscope (AFM) and then investigated by our Schwarzschild Objective (SO) based EUV microscope. Possible defect detection limits with large field of view (FOV) and moderate magnification will be discussed in terms of required source photon flux and detection camera performance.