Testing of Radiation Hardness in the Extreme-Ultraviolet Spectral Region

Currently we are commissioning a second multilayer‐based beamline to study the radiation hardness of multilayers under extreme‐ultraviolet (EUV) irradiation in an oxidizing atmosphere. Multilayer lifetime is one of the most important issues for the commercialization of extreme‐ultraviolet lithography. The beamline employs a spherical multilayer mirror and a beryllium filter. The mirror demagnifies the source and reflects 13.4 nm radiation as well as visible light. The beryllium filter suppresses the visible light reflected by the mirror and provides also a barrier between the extremely clean storage ring vacuum and the water atmosphere of the test chamber.