Spectral filter for splitting the primary radiation from a generated beam with primary electromagnetic radiation having a wavelength in the extreme ultraviolet (EUV radiation) or soft X-ray (soft X) wavelength range and parasitic radiation having a wavelength in the infrared wavelength range (IR radiation) in an optical device, comprising a surface for reflecting electromagnetic radiation with a wavelength in the extreme ultraviolet wavelength range (EUV radiation), the surface being formed by an EUV radiation-reflecting multilayer structure, which multilayer structure has a a pattern of at least one system of concentric grooves mutually separated by concentric rings, wherin the width and depth of the grooves and the width of the rings are selected such that the concentric grooves and rings form Fresnel zones for reflecting radiation with a wavelength in the infrared wavelength range (IR radiation) incident on these grooves and rings, and method for the manufacture thereof.
|Patent number||WO 2012/023853 A1|
|Publication status||Submitted - 23 Feb 2012|
van Goor, F. A., Bijkerk, F., van den Boogaard, T., & van der Meer, R. (2012). Spectral filter for splitting a beam with electromagnetic radiation having wavelengths in the extreme ultraviolet (EUV) or soft X-Ray (Soft X) and the infrared (IR) wavelength range. Manuscript submitted for publication. (Patent No. WO 2012/023853 A1).