US 7,463,413 B2
Spectral purity filter for a multi-layer mirror, lithographic apparatus including such multi-layer mirror, method for enlarging the ratio of desired radiation and undesired radiation, and device manufacturing method
Maarten Marinus Johannes Wilhelmus Van Herpen, Heesch (Netherlands); Levinus Pieter Bakker, Helmond (Netherlands); Vadim Yevgenyevich Banine, Helmond (Netherlands); and Derk Jan Wilfred Klunder, Geldrop (Netherlands)
Assigned to ASML Netherlands B.V., Veldhoven (Netherlands)
Filed on Jan. 24, 2006, as Appl. No. 11/337,807.
Application 11/337807 is a continuation in part of application No. 11/115406, filed on Apr. 27, 2005.
Prior Publication US 2006/0245058 A1, Nov. 02, 2006
This patent is subject to a terminal disclaimer.
Int. Cl. F21V 9/04 (2006.01); F21V 9/06 (2006.01); G02B 5/08 (2006.01); G02B 5/20 (2006.01)
U.S. Cl. 359—359  [359/588; 359/589; 355/71] 21 Claims
OG exemplary drawing
 
1. A multi-layer mirror, comprising a multi-layer stack, the multi-layer stack comprising a plurality of alternating layers with a multi-layer stack top layer and a spectral filter top layer arranged on the multi-layer stack, the spectral filter top layer comprising a first spectral purity enhancement layer comprising a first material and having a layer thickness d1 and being arranged on the multi-layer stack top layer, wherein the first material is selected from SiN, Si3N4, SiO2, ZnS, Te, diamond, CsI, Se, SiC, amorphous carbon, MgF2, CaF2, TiO2, Ge, PbF2, ZrO2, BaTiO3, LiF or NaF, wherein the first material and the layer thickness d1 are selected to enlarge the ratio of radiation having a wavelength selected from a first wavelength range of 5-20 nm and radiation having a wavelength selected from a second wavelength range of 100-400 nm in a beam of radiation of a source emitting radiation with a wavelength in each wavelength range.