Mirror, in particular for a microlithographic projection exposure apparatus

Patent metadata

Field	Value
Publication number	US-11809085-B2
Application number	US-202117555573-A
Country	US
Kind code	B2
Filing date	Dec 20, 2021
Priority date	Jun 19, 2019
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

A microlithographic projection exposure mirror has a mirror substrate (12, 32), a reflection layer system (21, 41) for reflecting electromagnetic radiation that is incident on the mirror's optical effective surface, and at least one piezoelectric layer (16, 36), which is arranged between the mirror substrate and the reflection layer system and to which an electric field for producing a locally variable deformation is applied by a first electrode arrangement situated on the side of the piezoelectric layer facing the reflection layer system, and by a second electrode arrangement situated on the side of the piezoelectric layer facing the mirror substrate. One of the electrode arrangements is assigned a mediator layer (17, 37, 51, 52, 53, 71) for setting an at least regionally continuous profile of the electrical potential along the respective electrode arrangement. The mediator layer has at least two mutually electrically insulated regions (17a, 17b, 17c, . . . ; 37a, 37b, 37c, . . . ).

First claim

What is claimed is:

1. Mirror having an optical effective surface, comprising:
a mirror substrate;
a reflection layer system that reflects electromagnetic radiation incident on the optical effective surface;
at least one piezoelectric layer, arranged between the mirror substrate and the reflection layer system; and
a first electrode arrangement situated on a side of the piezoelectric layer facing the reflection layer system, and a second electrode arrangement situated on a side of the piezoelectric layer facing the mirror substrate;
wherein the first electrode arrangement and the second electrode arrangement are arranged to apply an electric field to the piezoelectric layer that produces a locally variable deformation in the piezoelectric layer;
wherein one of the electrode arrangements is assigned a mediator layer having an electrical conductivity less than 200 siemens/meter that sets an at least regionally continuous electrical potential profile along the respective electrode arrangement; and
wherein the mediator layer has at least two mutually electrically insulated regions, wherein the mutually electrically insulated regions of the mediator layer extend along the piezoelectric layer.

2. Mirror according to claim 1 , wherein the electrode arrangement to which the mediator layer is assigned has a plurality of electrodes, each of which is structured to have an electrical voltage relative to the respective other electrode arrangement applied via a lead.

3. Mirror according to claim 2 , wherein the mediator layer is structured to provide a plurality of mutually electrically insulated regions, wherein said the respective regions are assigned to different electrodes or to different clusters of the electrodes.

4. Mirror according to claim 3 , wherein the structuring makes possible an electric current flow across the mediator layer only between directly adjacent electrodes.

5. Mirror according to claim 3 , wherein the structuring makes possible an electric current flow across the mediator layer only between electrodes respectively associated with a same cluster.

6. Mirror according to claim 5 , wherein the number of electrodes in the respective clusters varies across the mediator layer.

7. Mirror according to claim 3 , further comprising a shielding electrode that at least partly shields the respective electrical potentials arranged between different ones of the electrodes or different ones of the clusters of the electrodes.

8. Mirror according to claim 7 , wherein the shielding electrode is provided with a defined electrical voltage or is operated with zero voltage.

9. Mirror according to claim 1 , wherein the mutually electrically insulated regions of the mediator layer are separated from one another by an electrically insulating material situated between the regions.

10. Mirror according to claim 9 , wherein the electrically insulating material situated between the regions comprises silicon dioxide (SiO 2 ) or Al 2 O 3 .

11. Mirror according to claim 1 , wherein the mutually electrically insulated regions of the mediator layer are separated from one another by a material having an electrical permittivity ε r of more than 1000.

12. Mirror according to claim 1 , wherein the piezoelectric layer extends between the mutually electrically insulated regions of the mediator layer.

13. Mirror according to claim 1 , wherein electrically insulating sections separate the mutually electrically insulated regions and have a maximum dimension of less than 10 μm in a plane parallel to the piezoelectric layer.

14. Mirror according to claim 1 , wherein the material of the mediator layer is selected from the group consisting essentially of titanium oxides, gallium nitrides, gallium oxides, aluminium nitrides, aluminium oxides and also mixed oxides comprising lanthanum (La), manganese (Mn), cobalt (Co), calcium (Ca), strontium (Sr), iron (Fe), copper (Cu) or nickel (Ni).

15. Mirror according to claim 1 , wherein the mirror is configured for an operating wavelength of less than 30 nm.

16. Mirror according to claim 1 , configured to produce a locally variable deformation in response to an electric field applied to the piezoelectric layer, wherein a maximum deviation of the deformation from a predefined desired profile is less than 2%.

17. Mirror according to claim 1 , wherein a distance between an optically used surface of the mirror and an edge of the mirror is less than 10 mm.

18. Mirror according to claim 1 , wherein the mediator layer has an average electrical sheet resistance of less than 10 kΩ.

19. Optical system configured as an illumination device or a projection lens in a microlithographic projection exposure apparatus and comprising a mirror according to claim 1 .

20. Mirror having an optical effective surface, comprising:
a mirror substrate;
a reflection layer system that reflects electromagnetic radiation incident on the optical effective surface;
at least one piezoelectric layer, arranged between the mirror substrate and the reflection layer system; and
a first electrode arrangement situated on a side of the piezoelectric layer facing the reflection layer system, and a second electrode arrangement situated on a side of the piezoelectric layer facing the mirror substrate;
wherein the first electrode arrangement and the second electrode arrangement are arranged to apply an electric field to the piezoelectric layer that produces a locally variable deformation in the piezoelectric layer;
wherein one of the electrode arrangements is assigned a mediator layer having an electrical conductivity less than 200 siemens/meter that sets an at least regionally continuous electrical potential profile along the respective electrode arrangement;
wherein the electrode arrangement to which the mediator layer is assigned has a plurality of electrodes, each of which is structured to have an electrical voltage relative to the respective other electrode arrangement applied via a lead; and
a shielding electrode that at least partly shields the respective electrical potentials arranged between different ones of the electrodes or different ones of the clusters of the electrodes.

21. Method for producing a mirror, comprising:
providing a mirror substrate;
applying a piezoelectric layer and also a first and a second electrode arrangement on the mirror substrate;
situating the first electrode arrangement on a side of the piezoelectric layer that faces away from the mirror substrate, and situating the second electrode arrangement on a side of the piezoelectric layer that faces the mirror substrate;
applying a mediator having an electrical conductivity less than 200 siemens/meter that sets an at least regionally continuous electrical potential profile along one of the electrode arrangements such that the mediator layer has at least two mutually electrically insulated regions, wherein the mutually electrically insulated regions of the mediator layer extend along the piezoelectric layer;
applying a reflection layer stack configured to reflect electromagnetic radiation having an operating wavelength that is incident on an optical effective surface of the mirror; and
applying an electric field that produces a locally variable deformation to the piezoelectric layer by way of the first electrode arrangement and the second electrode arrangement.

22. Method according to claim 21 , wherein said applying the mediator layer comprises structuring the mediator layer lithographically or using laser ablation.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Stiepan Hans Michael
• Gruner Toralf

Classifications

• G03F7/70316 Primary

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

• C03C17/10

  by deposition from the liquid phase · CPC title

• G02B5/0891

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

• G02B26/0858 Primary

  the reflecting means being moved or deformed by piezoelectric means · CPC title

• G03F7/7015

  Details of optical elements · CPC title