Arrangement for actuating at least one optical element in an optical system

Patent metadata

Field	Value
Publication number	US-9665011-B2
Application number	US-201514670223-A
Country	US
Kind code	B2
Filing date	Mar 26, 2015
Priority date	Nov 29, 2012
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

The invention relates to an arrangement for actuating an element in an optical system, in particular an optical system of a projection exposure apparatus, wherein the optical element is tiltable about at least one tilting axis via at least one joint having a joint stiffness, comprising at least one actuator for exerting a force on the optical element, wherein the actuator has an actuator stiffness which at least partly compensates for the joint stiffness.

First claim

The invention claimed is:

1. An arrangement, comprising:
a joint having a joint stiffness;
an optical element that is tiltable about a tilting axis via the joint; and
an actuator configured to exert a force on the optical element,
wherein the actuator has an actuator stiffness configured to at least partly compensate for the joint stiffness, and the actuator stiffness and the joint stiffness deviate from one another in terms of absolute value by at most 50 percent of the actuator stiffness over the operating range of the actuator.

2. The arrangement of claim 1 , wherein the actuator stiffness and the joint stiffness have mutually opposite signs over an operating range of the actuator.

3. The arrangement of claim 1 , wherein the actuator stiffness and the joint stiffness deviate from one another in terms of absolute value by at most 30 percent of the actuator stiffness over the operating range of the actuator.

4. The arrangement of claim 1 , wherein the actuator stiffness and the joint stiffness deviate from one another in terms of absolute value by at most 10 percent of the actuator stiffness over the operating range of the actuator.

5. The arrangement of claim 1 , wherein the actuator stiffness and the joint stiffness deviate from one another in terms of absolute value by at most five percent of the actuator stiffness over the operating range of the actuator.

6. The arrangement of claim 1 , wherein the actuator stiffness and the joint stiffness deviate from one another in terms of absolute value by at most one percent of the actuator stiffness over the operating range of the actuator.

7. The arrangement of claim 1 , wherein the actuator comprises:
a rotor comprising a magnet; and
a stator comprising a coil configured to have electric current applied thereto during use of the actuator.

8. The arrangement of claim 7 , further comprising a separating layer between the rotor and the stator, wherein the separating layer is configured to provide a vacuum seal.

9. The arrangement of claim 8 , further comprising a parallel guide for the optical element.

10. The arrangement of claim 9 , wherein the parallel guide is configured to translate a force acting between the rotor and the stator into a force component parallel to a drive direction of the actuator so that the force component at least partly compensates for the joint stiffness.

11. The arrangement of claim 9 , wherein parallel guide comprises two leaf spring elements.

12. The arrangement of claim 1 , further comprising a parallel guide for the optical element.

13. The arrangement of claim 12 , wherein parallel guide comprises two leaf spring elements.

14. The arrangement of claim 1 , wherein the optical element is tiltable about two tilting axes.

15. The arrangement of claim 1 , wherein the optical element is tiltable about two mutually perpendicular tilting axes.

16. The arrangement of claim 1 , wherein the optical element comprises a facet mirror.

17. An apparatus, comprising:
an arrangement according to claim 1 ,
wherein the apparatus is a projection exposure apparatus.

18. The apparatus of claim 17 , wherein the apparatus is configured to operate with an operating wavelength of less than 30 nm.

19. The apparatus of claim 17 , wherein the apparatus is configured to operate with an operating wavelength of less than 15 nm.

20. An optical system, comprising:
a plurality of optical elements;
a plurality of joints; and
a plurality of actuators,
wherein:
for each of the plurality of optical elements:
the optical element has a corresponding joint and a corresponding actuator;
the optical element is tiltable about a tilting axis via its corresponding joint;
the corresponding actuator is configured to exert a force on the optical element;
the corresponding joint has a joint stiffness;
the corresponding actuator has an actuator stiffness configured to at least partly compensate for the joint stiffness of the corresponding joint; and
the actuator stiffness and the joint stiffness deviate from one another in terms of absolute value by at most 50 percent of the actuator stiffness over the operating range of the actuator.

21. The optical system of claim 20 , wherein the optical elements are independently adjustable.

22. The optical system of claim 20 , wherein the actuators are arranged in two different planes.

23. The optical system of claim 20 , wherein the actuators are arranged in three different planes.

24. The optical system of claim 20 , wherein an optical element comprises a facet mirror.

25. The optical system of claim 20 , wherein an optical element comprises a field facet mirror.

26. The optical system of claim 20 , wherein the optical system is an optical system of a microlithographic projection exposure apparatus.

27. An apparatus, comprising:
an optical system according to claim 20 ,
wherein the apparatus is a projection exposure apparatus.

28. The apparatus of claim 27 , wherein the apparatus is configured to operate with an operating wavelength of less than 30 nm.

29. The apparatus of claim 27 , wherein the apparatus is configured to operate with an operating wavelength of less than 15 nm.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Hauf Markus
• Vogler Alexander

Classifications

• G03F7/70075 Primary

  Homogenization of illumination intensity in the mask plane by using an integrator, e.g. fly's eye lens, facet mirror or glass rod, by using a diffusing optical element or by beam deflection · CPC title

• G02B26/0833

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title

• G03F7/70825

  Mounting of individual elements, e.g. mounts, holders or supports (workpiece or mask holders G03F7/707) · 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

• G02B26/0816

  by means of one or more reflecting elements · CPC title