GRATING BASED SPECTRAL FILTER FOR ELIMINATING OUT OF BAND RADIATION IN AN EXTREME ULTRA-VIOLET LITHOGRAPHY SYSTEM

摘要

There is provided an attenuator for attenuating electromagnetic radiation of wavelengths Unequal to a used wavelength, including a grating element having i) grating grooves that produce a grating period (p), and ii) a grating plane. The grating period (p) is least about 150 times higher than the used wavelength.