Optical system of a microlithographic projection exposure apparatus

Patent metadata

Field	Value
Publication number	US-9817317-B2
Application number	US-201414513944-A
Country	US
Kind code	B2
Filing date	Oct 14, 2014
Priority date	Apr 16, 2012
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

The invention relates to an optical system of a microlithographic projection exposure apparatus, in particular for operation in the EUV, comprising at least one polarization-influencing arrangement having a first reflection surface and a second reflection surface, wherein the first reflection surface and the second reflection surface are arranged at an angle of 0°±10° or at an angle of 90°±10° relative to one another, wherein light incident on the first reflection surface during the operation of the optical system forms an angle of 45°±5° with the first reflection surface, and wherein the polarization-influencing arrangement is rotatable about a rotation axis running parallel to the light propagation direction of light incident on the first reflection surface during the operation of the optical system.

First claim

The invention claimed is:

1. An optical system, comprising:
a polarization-influencing arrangement comprising a first reflection surface and a second reflection surface,
wherein:
the first and second reflection surfaces are arranged at an angle of 0°±10° relative to each other, or the first and second reflection surfaces are arranged at an angle of 90°±10° relative to each other;
during use of the optical system, light incident on the first reflection surface has an angle of 45°±5° relative to the first reflection surface;
the polarization-influencing arrangement is rotatable about a rotation axis which is parallel to a light propagation direction of light incident on the first reflection surface during operation of the optical system;
the polarization-influencing arrangement is configured so that, during operation of the optical system, the polarization-influencing arrangement converts unpolarized light incident on the first reflection surface into linearly polarized light emerging from the second reflection surface;
there is no reflection surface along the light path between the first and second reflection surfaces; and
the optical system is an EUV microlithographic optical system.

2. The optical system of claim 1 , wherein, during operation of the optical system, a light ray reflected by the second reflection surface is reflected in a direction which is parallel to a direction of the light incident on the first reflection surface.

3. The optical system of claim 1 , further comprising a mirror element configured so that, during operation of the optical system, light reflected at the second reflection surface is subsequently reflected by the mirror element.

4. The optical system of claim 3 , wherein the mirror element is tiltable about an axis.

5. The optical system of claim 3 , wherein the mirror element comprises an optically active surface having substantially annular geometry.

6. The optical system of claim 1 , wherein the second reflection surface is tiltable about an axis.

7. The optical system of claim 1 , wherein:
the optical system comprises an array which comprises plurality of polarization-influencing arrangements; and
for each polarization-influencing arrangement:
the polarization-influencing element comprises a first reflection surface and a second reflection surface;
the first and second reflection surfaces are arranged at an angle of 0°±10° relative to each other, or the first and second reflection surfaces are arranged at an angle of 90°±10° relative to each other;
during use of the optical system, light incident on the first reflection surface has an angle of 45°±5° relative to the first reflection surface; and
the polarization-influencing arrangement is rotatable about a rotation axis which is parallel to a light propagation direction of light incident on the first reflection surface during operation of the optical system.

8. The optical system of claim 7 , wherein the array comprises reflection surfaces adjacent to each other in one of two mutually perpendicular spatial directions which run parallel to each other.

9. The optical system of claim 7 , further comprising a mirror arrangement comprising a plurality of individual mirrors configured so that, during operation of the optical system, light emerging from the second reflection surfaces is reflected by mirror arrangement.

10. The optical system of claim 9 , wherein the individual mirrors are adjustable independently of each other.

11. The optical system of claim 1 , further comprising a mirror element, wherein during operation of the optical system:
the mirror element reflects light reflected at the second reflection surface; and
a light ray reflected by the second reflection surface is reflected in a direction which is parallel to a direction of the light incident on the first reflection surface.

12. The optical system of claim 1 , wherein, during operation of the optical system, light is incident on the first reflection surface with an angle of incidence that is within 5° of the Brewster angle for the first reflection surface at an operating wavelength of the optical system.

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

14. The device of claim 13 , comprising:
a field facet mirror comprising a plurality of field facets; and
a pupil facet mirror comprising a plurality of pupil facets,
wherein:
the device is configured so that, during use of the device, a polarization-influencing element is in a path of a light ray reflected at the field facets to influence a polarization state of the light ray.

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

16. The apparatus of claim 15 , wherein:
for each mirror arranged in the illumination device and/or in the projection lens downstream of the polarization-influencing arrangement in a light propagation direction during operation of the apparatus, a reflection surface of the mirror is arranged at an angle with respect to the light incident on the reflection surface of the mirror; and
the angle is at most 20° or the angle is 90°±10°.

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

18. The optical system of claim 1 , wherein the polarization-influencing arrangement comprises precisely two reflection surfaces.

19. The optical system of claim 1 , further comprising a mirror element configured so that, during operation of the optical system, light reflected from the mirror element impinges on the first reflection surface.

20. The optical system of claim 1 , further comprising first and second mirror elements, wherein:
the first mirror element is configured so that, during operation of the optical system, light reflected from the mirror element impinges on the first reflection surface; and
the second mirror element is configured so that, during operation of the optical system, light reflected at the second reflection surface is subsequently reflected by the mirror element.

21. An optical system, comprising:
a polarization-influencing arrangement comprising a first reflection surface and a second reflection surface; and
a mirror element configured so that, during operation of the optical system, light reflected at the second reflection surface is subsequently reflected by the mirror element,
wherein:
the mirror element comprises an optically active surface having substantially annular geometry;
the first and second reflection surfaces are arranged at an angle of 0°±10° relative to each other, or the first and second reflection surfaces are arranged at an angle of 90°±10° relative to each other;
during use of the optical system, light incident on the first reflection surface has an angle of 45°±5° relative to the first reflection surface;
the polarization-influencing arrangement is rotatable about a rotation axis which is parallel to a light propagation direction of light incident on the first reflection surface during operation

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Saenger Ingo
• Schlesener Frank

Classifications

• G03F7/70566

  Polarisation control · CPC title

• G03F7/70075

  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

• G03F7/70108

  Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides · CPC title

• G02B5/3066

  involving the reflection of light at a particular angle of incidence, e.g. Brewster's angle · CPC title

• G03F7/70191 Primary

  Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like · CPC title