title: Infrared antireflective filtering for extreme ultraviolet multilayer Bragg reflectors.
abstract: An extreme ultraviolet multilayer mirror with an integrated spectral filter for the IR range is presented and experimentally evaluated. The system consists of an IR-transparent B4C/Si multilayer stack which is used both as EUV-reflective coating and as a phase shift layer of the resonant IR antireflective (AR) coating. The AR coating is optimized in our particular case to suppress CO2 laser radiation at a wavelength of 10.6 μm, and a suppression of more than two orders of magnitude is demonstrated. The method allows high suppression over a large angular acceptance range, relevant for application in lithography systems.
authors.affiliation: FOM Institute DIFFER, Nieuwegein, The Netherlands.
authors.forename: V V
authors.initials: VV
authors.lastname: Medvedev
authors.forename: A E
authors.initials: AE
authors.lastname: Yakshin
authors.forename: R W E
authors.initials: RW
authors.lastname: van de Kruijs
authors.forename: V M
authors.initials: VM
authors.lastname: Krivtsun
authors.forename: A M
authors.initials: AM
authors.lastname: Yakunin
authors.forename: K N
authors.initials: KN
authors.lastname: Koshelev
authors.forename: F
authors.initials: F
authors.lastname: Bijkerk