Optical system of a microlithographic projection exposure apparatus

Patent metadata

Field	Value
Publication number	US-9720327-B2
Application number	US-201514721426-A
Country	US
Kind code	B2
Filing date	May 26, 2015
Priority date	Dec 14, 2012
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

The invention relates to an optical system of a microlithographic projection exposure apparatus, in particular for operation in the EUV, comprising a mirror arrangement composed of a plurality of mutually independently adjustable mirror elements, and at least one polarization-influencing arrangement arranged upstream of the mirror arrangement relative to the light propagation direction, wherein the polarization-influencing arrangement has a group of first reflection surfaces and a group of second reflection surfaces, wherein the first reflection surfaces are tiltable independently of one another, and wherein, during the operation of the optical system, light reflected at respectively one of the first reflection surfaces can be directed onto the mirror arrangement via respectively a different one of the second reflection surfaces depending on the tilting of the first reflection surface.

First claim

The invention claimed is:

1. An optical system, comprising:
a mirror arrangement comprising a plurality of mutually independently adjustable mirror elements; and
a polarization-influencing arrangement upstream of the mirror arrangement along a path light follows through the optical system during use of the optical system,
wherein:
the polarization-influencing arrangement comprises a group of first reflection surfaces and a group of second reflection surfaces;
the first reflection surfaces are tiltable independently of one another;
the optical system is configured so that, during the use of the optical system, light reflected at a first reflection surface is directed onto the mirror arrangement via a second reflection surface depending on a tilt of the first reflection surface;
the optical system has a pupil plane;
the mirror arrangement is upstream of the pupil plane; and
the optical system is a microlithographic optical system.

2. The optical system of claim 1 , wherein the first reflection surfaces are tiltable independently of each other about two mutually perpendicular tilting axes.

3. The optical system of claim 1 , wherein, during use of the optical system, light is incident on the first reflection surface at an angle of incidence which is ±5° relative to the Brewster angle for the first reflection surface at an operating wavelength of the optical system.

4. The optical system of claim 3 , wherein, during use of the optical system, light is incident on the second reflection surface at an angle of incidence which is ±5° relative to the Brewster angle for the second reflection surfaces at an operating wavelength of the optical system.

5. The optical system of claim 1 , wherein, during use of the optical system, light is incident on the second reflection surface at an angle of incidence which is ±5° relative to the Brewster angle for the second reflection surface at an operating wavelength of the optical system.

6. The optical system of claim 1 , wherein, during use of the optical system, a light ray is reflected by the second reflection surface in an output direction which deviates by a maximum of ±15° from a direction of incidence of the light ray on the first reflection surface.

7. The optical system of claim 1 , wherein, during use of the optical system, a light ray is reflected by the second reflection surface in an output direction which deviates by a maximum of ±10° from a direction of incidence of the light ray on the first reflection surface.

8. The optical system of claim 1 , wherein, during use of the optical system, a light ray is reflected by the second reflection surface in an output direction which deviates by a maximum of ±5° from a direction of incidence of the light ray on the first reflection surface.

9. The optical system of claim 1 , wherein the polarization-influencing arrangement is configured so that, during use of the optical system, the light incident on the first reflection surface emerges from the second reflection surface as linearly polarized light.

10. The optical system of claim 9 , wherein, during use of the optical system, light incident on the first reflection surface is unpolarized.

11. The optical system of claim 9 , wherein, during use of the optical system, light incident on the first reflection surface is circularly polarized.

12. The optical system of claim 1 , wherein the group of first reflection surfaces comprises a strip mirror unit comprising a plurality of mutually independently adjustable strip mirrors.

13. The optical system of claim 1 , wherein the first reflection surfaces are partly transmissive to light at an operating wavelength of the optical system.

14. The optical system of claim 1 , wherein the group of second reflection surfaces is configured so that, during use of the optical system, the group of second reflection surfaces completely illuminates the mirror arrangement.

15. The optical system of claim 1 , wherein the polarization-influencing arrangement is configured to that, during use of the optical system, the first reflection surfaces do not change a polarization state of the light passing through the optical system.

16. The optical system of claim 1 , wherein the polarization-influencing arrangement is configured so that, during use of the optical system, the polarization-influencing arrangement generates an at least approximately tangential polarization distribution in the pupil plane of the optical system.

17. The optical system of claim 1 , wherein the polarization-influencing arrangement is configured so that, during use of the optical system, the polarization-influencing arrangement generates an at least approximately radial polarization distribution in the pupil plane of the optical system.

18. An illumination device, comprising:
an optical system according to claim 1 ,
wherein the illumination device is an EUV microlithographic illumination device.

19. An apparatus, comprising:
an illumination device comprising an optical system according to claim 1 ; and
a projection lens,
wherein the apparatus is an EUV microlithographic projection exposure apparatus.

20. A method of operating a microlithographic projection exposure apparatus comprising an illumination device and a projection lens, the method comprising:
using the illumination system to illuminate structures of a mask; and
using the projection lens to project the illuminated structures of the mask onto a light-sensitive material,
wherein the illumination device comprises an optical system according to claim 1 .

21. The optical system of claim 1 , wherein:
the optical system is configured so that, during use of the optical system, the optical system illuminates a reticle in an object plane; and
the mirror arrangement is in a field plane that is conjugate to the object plane.

22. An optical system, comprising:
a mirror arrangement comprising a plurality of mutually independently adjustable mirror elements; and
a polarization-influencing arrangement upstream of the mirror arrangement along a path light follows through the optical system during use of the optical system,
wherein:
the polarization-influencing arrangement comprises a group of first reflection surfaces and a group of second reflection surfaces;
the first reflection surfaces are tiltable independently of one another;
the optical system is configured so that, during the use of the optical system, light reflected at a first reflection surface is directed onto the mirror arrangement via a second reflection surface depending on a tilt of the first reflection surface;
the optical system is configured so that, during use of the optical system, the optical system illuminates a reticle in an object plane;
the mirror arrangement is in a field plane that is conjugate to the object plane; and
the optical system is a microlithographic optical system.

23. An optical system, comprising:
a mirror arrangement comprising a plurality of mutually independently adjustable mirror elements; and
a polarization-influencing arrangement upstream of the mirror arrangement along a path light follows through the optical system during use of the optical system,
wherein:
the polarization-influencing arrangement comprises a group of first reflection surfaces and a group of second reflection surfaces;
the first reflection surfaces are tiltable independently of one another;
the optical system is configured so that, during the use of the optical system;
light i

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Maul Manfred

Classifications

• G02B5/3075

  for use in the UV (G02B5/3066 takes precedence) · CPC title

• G02B27/28

  for polarising (used in stereoscopes G02B30/25) · CPC title

• G03F7/70116

  Off-axis setting using a programmable means, e.g. liquid crystal display [LCD], digital micromirror device [DMD] or pupil facets · CPC title

• G03F7/702

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

• G02B5/3091

  for use in the UV · CPC title