Method for correcting the surface form of a mirror

Patent metadata

Field	Value
Publication number	US-2016299268-A1
Application number	US-201615135019-A
Country	US
Kind code	A1
Filing date	Apr 21, 2016
Priority date	Mar 15, 2011
Publication date	Oct 13, 2016
Grant date	—

Abstract

A minor reflecting radiation with an operating wavelength of 5-30 nm, includes a substrate and a reflective coating. The reflective coating includes a first group of layers ( 19 ) and a second group ( 5 ) of layers, such that the second group of layers is arranged between the substrate and the first group of layers. The first group and the second group of layers comprise a plurality of first and second layers ( 9, 11 ). The first layers have a refractive index for radiation having the operating wavelength which is greater than a refractive index of the second layers for radiation having the operating wavelength. A correction layer ( 13 ) has a layer thickness variation for correcting the surface form of the minor and is arranged between the second group and the first group of layers. The correction layer contains carbon, sulfur, phosphorus, fluorine or organic compounds thereof, and inorganic metal compounds.

First claim

1 . A mirror configured to reflect radiation having an operating wavelength in the range of 5-30 nm, comprising a substrate and a reflective coating,
wherein the reflective coating comprises a first group of layers and a second group of layers, wherein the second group of layers is arranged between the substrate and the first group of layers, wherein the first group and the second group of layers comprise a plurality of first and second layers arranged alternately one above another, wherein the first layers have a refractive index for radiation having the operating wavelength which is greater than a refractive index of the second layers for radiation having the operating wavelength, and wherein a correction layer having a layer thickness variation for correcting a surface form of the mirror is arranged between the second group and the first group of layers, wherein the correction layer contains at least one of the following: carbon, sulfur, phosphorus, fluorine or organic compounds based on these elements, and inorganic metal compounds.

2 . The mirror according to claim 1 , wherein
the first group of layers comprises a number of layers which is greater than 20.

3 . The mirror according to claim 1 , wherein
the second group of layers and the first group of layers are configured to reflect mutually same operating wavelengths.

4 . A projection lens for a microlithography exposure apparatus comprising a mirror as claimed in claim 1 .

5 . A microlithography projection exposure apparatus comprising a projection lens as claimed in claim 4 .

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Mueller Juergen
• Schicketanz Thomas
• Ehm Dirk Heinrich

Classifications

• G21K1/062

  Devices having a multilayer structure · CPC title

• G03F7/70166

  Capillary or channel elements, e.g. nested extreme ultraviolet [EUV] mirrors or shells, optical fibers or light guides · CPC title

• G02B5/0816 Primary

  Multilayer mirrors, i.e. having two or more reflecting layers (G02B5/0883, G02B5/0891 take precedence) · CPC title

• G02B5/0891 Primary

  Ultraviolet [UV] mirrors (apparatus for microlithography exposure G03F7/70; X-ray multilayer structures G21K1/06) · CPC title

• G03F7/70233

  Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems · CPC title