Mirror, more particularly for a microlithographic projection exposure apparatus

Patent metadata

Field	Value
Publication number	US-2016209751-A1
Application number	US-201615082555-A
Country	US
Kind code	A1
Filing date	Mar 28, 2016
Priority date	Sep 27, 2013
Publication date	Jul 21, 2016
Grant date	—

Abstract

A mirror, in particular for a microlithographic projection exposure apparatus has an optically effective surface ( 11 ), a mirror substrate ( 12 ), a reflection layer stack ( 21 ) for reflecting electromagnetic radiation that is incident on the optical effective surface, and at least two piezoelectric layers ( 16 a, 16 b, 16 c ), which are arranged successively between the mirror substrate and the reflection layer stack in the stack direction of the reflection layer stack and to which an electric field can be applied to produce a locally variable deformation, wherein at least one intermediate layer ( 22 a, 22 b ) made of crystalline material is arranged between the piezoelectric layers ( 16 a, 16 b, 16 c ), wherein the intermediate layer is designed to leave an electric field, which is present in the region of the piezoelectric layers ( 16 a, 16 b, 16 c ) that adjoin the intermediate layer ( 22 a, 22 b ) in the stack direction of the reflection layer stack ( 21 ), substantially uninfluenced.

First claim

What is claimed is:

1 . A mirror having an optically effective surface, comprising
a mirror substrate; a reflection layer stack configured to reflect electromagnetic radiation that is incident on the optically effective surface; at least a first and a second piezoelectric layer, which are arranged successively between the mirror substrate and the reflection layer stack in a stack direction of the reflection layer stack and configured to receive an electric field to produce a locally variable deformation in the piezoelectric layers; and at least one intermediate layer of crystalline material arranged between the first and the second piezoelectric layers; wherein the intermediate layer has substantially no influence on an electric field applied in a region of the piezoelectric layers that adjoin the intermediate layer in the stack direction of the reflection layer stack.

2 . The mirror as claimed in claim 1 , wherein the mirror has at least three piezoelectric layers, which are arranged successively between the mirror substrate and the reflection layer stack in the stack direction of the reflection layer stack.

3 . The mirror as claimed in claim 1 , wherein the crystalline material is selected from the group consisting of crystalline quartz (SiO 2 ), calcium niobate (CaNbO 3 ) and strontium titanate (SrTiO 3 )

4 . The mirror as claimed in claim 1 , wherein the at least one intermediate layer is made from electrically insulating material.

5 . The mirror as claimed in claim 1 , wherein the piezoelectric layers each have a thickness of less than 3.0 μm.

6 . The mirror as claimed in claim land configured for an operating wavelength of less than 30 nm.

7 . The mirror as claimed in claim 1 and configured for a microlithographic projection exposure apparatus.

8 . An optical system having a mirror as claimed in claim 1 .

9 . The optical system as claimed in claim 8 , wherein the mirror is arranged in a plane, in which a parameter P(M), which is defined as

P


(
M
)

=

D


(
SA
)

D


(
SA
)

+

D


(
CR
)

,

is at least 0.8, with D(SA) designating a subaperture diameter and D(CR) designating a maximum chief ray distance over all field points of the optically used field on the optical surface M in the relevant plane.

10 . The optical system as claimed in claim 8 , wherein the mirror is arranged in a plane, in which a parameter P(M), which is defined as

P


(
M
)

=

D


(
SA
)

D


(
SA
)

+

D


(
CR
)

,

is at most 0.2, with D(SA) designating the subaperture diameter and D(CR) designating the maximum chief ray distance over all field points of the optically used field on the optical surface M in the relevant plane.

11 . A microlithographic projection exposure apparatus comprising an illumination device and a projection lens, the projection exposure apparatus having an optical system as claimed in claim 8 .

12 . The mirror as claimed in claim 5 , wherein the piezoelectric layers each have a thickness ranging from 1 μm to 2 μm.

13 . The mirror as claimed in claim 6 and configured for an operating wavelength of less than 15 nm.

14 . The optical system as claimed in claim 8 and configured as an illumination device or a projection lens of a microlithographic projection exposure apparatus.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Gruner Toralf
• Hild Kerstin

Classifications

• G21K1/062 Primary

  Devices having a multilayer structure · CPC title

• G02B5/0816

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

• G03F7/702 Primary

  Reflective illumination, i.e. reflective optical elements other than folding mirrors, e.g. extreme ultraviolet [EUV] illumination systems · CPC title

• G02B5/0891 Primary

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

• G03F7/70316

  Details of optical elements, e.g. of Bragg reflectors, extreme ultraviolet [EUV] multilayer or bilayer mirrors or diffractive optical elements · CPC title