Wavefront correction element for use in an optical system

Patent metadata

Field	Value
Publication number	US-10684553-B2
Application number	US-201916595800-A
Country	US
Kind code	B2
Filing date	Oct 8, 2019
Priority date	Apr 11, 2017
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

A wavefront correction element for use in an optical system, in particular in an optical system of a microlithographic projection exposure apparatus, includes a substrate ( 220, 230 ), an arrangement of electrically conductive conductor tracks ( 222, 232 ) provided on the substrate, wherein a wavefront of electromagnetic radiation incident on the wavefront correction element is manipulatable by electrical driving of the conductor tracks, and an insulating layer ( 221, 231 ), which electrically insulates the conductor tracks from one another, wherein the insulating layer has first regions and second regions, wherein the electrical breakdown strength of the insulating layer to withstand a breakdown of electrical charge through the insulating layer as far as the arrangement of conductor tracks is lower in the second regions than in the first regions by at least a factor of two.

First claim

What is claimed is:

1. A wavefront correction element for use in an optical system, comprising:
a substrate;
an arrangement of electrically conductive conductor tracks provided on the substrate and configured to be electrically driven to manipulate a wavefront of electromagnetic radiation incident on the wavefront correction element; and
an insulating layer, which electrically insulates the conductor tracks from one another;
wherein the insulating layer has first regions and second regions, wherein an electrical breakdown strength of the insulating layer to withstand a breakdown of electrical charge through the insulating layer as far as the arrangement of conductor tracks is lower in the second regions than in the first regions by at least a factor of two.

2. The wavefront correction element as claimed in claim 1 , wherein the second regions have a reduced density in comparison with a density of the first regions.

3. The wavefront correction element as claimed in claim 1 , wherein the insulating layer has channel-shaped defects extending as far as the arrangement of conductor tracks in the second regions.

4. The wavefront correction element as claimed in claim 1 , wherein the insulating layer comprises quartz glass (SiO 2 ).

5. The wavefront correction element as claimed in claim 1 and configured as a transmissive optical element.

6. The wavefront correction element as claimed in claim 1 and configured as a reflective optical element.

7. The wavefront correction element as claimed in claim 1 and configured for an operating wavelength of less than 30 nm.

8. An optical system of a microlithographic projection exposure apparatus, comprising at least one wavefront correction element which is embodied as claimed in claim 1 .

9. A microlithographic projection exposure apparatus comprising an illumination device and a projection lens, wherein at least one of the illuminating device and the projection lens comprises a wavefront correction element as claimed in claim 1 .

10. A wavefront correction element for use in an optical system, comprising:
a substrate;
an arrangement of electrically conductive conductor tracks provided on the substrate and configured to be electrically driven to manipulate a wavefront of electromagnetic radiation incident on the wavefront correction element; and
an insulating layer, which electrically insulates the conductor tracks from one another;
wherein the insulating layer has channel-shaped defects extending as far as the arrangement of conductor tracks.

11. The wavefront correction element as claimed in claim 1 , wherein the insulating layer comprises particles that disturb layer growth of the insulating layer.

12. The wavefront correction element as claimed in claim 11 and configured to operate at an operating wavelength, wherein the insulating layer comprises a first material and the particles comprise a second material, wherein refractive indices of the first material and of the second material differ from one another by a maximum of 10% at the operating wavelength.

13. The wavefront correction element as claimed in claim 12 , wherein the second material is selected from the group consisting essentially of quartz glass (SiO 2 ) and calcium fluoride (CaF 2 ).

14. A method for producing a wavefront correction element, comprising:
a) providing a substrate;
b) applying an arrangement of electrically conductive conductor tracks on the substrate; and
c) applying an insulating layer, which electrically insulates the conductor tracks from one another;
wherein applying the insulating layer comprises providing the insulating layer with first regions and with second regions, and
wherein an electrical breakdown strength of the insulating layer to withstand a breakdown of electrical charge through the insulating layer as far as the arrangement of conductor tracks is lower in the second regions than in the first regions by at least a factor of two.

15. The method as claimed in claim 14 , wherein applying the insulating layer is carried out in a coating process in which the layer-forming particles have an energy of no more than 5 eV.

16. The method as claimed in claim 15 , wherein the coating process is a plasma enhanced chemical vapor deposition process or a physical vapor deposition process.

17. The method as claimed in claim 14 , further comprising applying particles that disturb a layer growth of the insulating layer before or during the process of applying the insulating layer.

18. The method as claimed in claim 17 , further comprising providing the wavefront correction element in an optical system, wherein the insulating layer comprises a first material and the particles comprise a second material, wherein refractive indices of the first material and of the second material differ from one another by a maximum of 10% at an operating wavelength of the optical system.

19. An optical system of a microlithographic projection exposure apparatus, comprising at least one wavefront correction element which is produced by the method as claimed in claim 14 .

20. A microlithographic projection exposure apparatus comprising an illumination device and a projection lens, wherein at least one of the illuminating device and the projection lens comprises a wavefront correction element which is produced by the method as claimed in claim 14 .

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Huber Peter

Classifications

• G03F7/70891

  Temperature · 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

• G03F7/70266 Primary

  Adaptive optics, e.g. deformable optical elements for wavefront control, e.g. for aberration adjustment or correction · CPC title

• G02B26/06

  for controlling the phase of light (G02B26/08 takes precedence {, measuring optical phase difference G01J9/00}) · CPC title

• G03F7/7015

  Details of optical elements · CPC title