Optical system of a microlithographic projection exposure apparatus

Patent metadata

Field	Value
Publication number	US-9323156-B2
Application number	US-201213661381-A
Country	US
Kind code	B2
Filing date	Oct 26, 2012
Priority date	Jun 10, 2010
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

An optical system of a microlithographic projection exposure apparatus includes at least one mirror arrangement having a plurality of mirror elements which are displaceable independently of each other for altering an angular distribution of the light reflected by the mirror arrangement. The optical system also includes a polarization-influencing optical arrangement including a first lambda/2 plate and at least one additional lambda/2 plate.

First claim

What is claimed is:

1. An optical system, comprising:
a mirror arrangement comprising a plurality of mirror elements which are displaceable independently of each other to alter an angular distribution of light reflected by the mirror arrangement during use of the optical system; and
a polarization-influencing optical arrangement comprising a first lambda/2 plate and a second lambda/2 plate,
wherein:
the first and second lambda/2 plates are arranged in succession along a light path that the light follows through the optical system during use of the optical system;
the first and second lambda/2 plates are upstream of a pupil plane along the light path that light follows through the optical system during use of the optical system;
the first and second lambda/2 plates are displaceable relative to each other; and
the optical system is configured to be used in a microlithographic projection exposure apparatus.

2. The optical system of claim 1 , wherein the first and second lambda/2 plates are translatable relative to each other.

3. The optical system of claim 1 , wherein the first and second lambda/2 plates are rotatable relative to each other.

4. The optical system of claim 1 , wherein the first and second lambda/2 plates are translatable in mutually different spatial directions.

5. The optical system of claim 1 , wherein the first and second lambda/2 plates are displaceable relative to each other with a degree of overlap which is variable in the light propagation direction.

6. The optical system of claim 1 , wherein the first lambda/2 plate is displaceable between a first position in which the first lambda/2 plate is completely outside an optically effective region of the mirror arrangement and a second position in which the first lambda/2 plate is disposed completely within the optically effective region of the mirror arrangement.

7. The optical system of claim 1 , wherein the first lambda/2 plate has a fast axis of birefringence, the second lambda/2 plate has a fast axis of birefringence, and an orientation of the fast axis of birefringence of the first lambda/2 plate is different from an orientation of the fast axis of the second lambda/2 plate.

8. The optical system of claim 1 , wherein a fast axis of birefringence of the first lambda/2 plate and a fast axis of the second lambda/2 plate are arranged at an angle of 45° ±5° relative to each other.

9. The optical system of claim 1 , wherein a vibration plane of a first linearly polarized light beam which passes only through the first lambda/2 plate during use of the optical system is rotated through a rotary angle, a vibration plane of a second linearly polarized light beam which passes only through the second lambda/2 plate during use of the optical system is rotated through a second angle, and the first angle is different from the second angle.

10. The optical system of claim 9 , wherein the first and second angles have the same absolute value but opposite signs.

11. The optical system of claim 1 , wherein the first and second lambda/2 plates define 90° rotator in an overlap region with each other.

12. The optical system of claim 1 , wherein the polarization-influencing optical arrangement comprises precisely two lambda/2 plates.

13. The optical system of claim 1 , wherein the polarization-influencing optical arrangement comprises a third lambda/2 plate.

14. The optical system of claim 1 , wherein the polarization-influencing optical arrangement is adjustable so that, during use of the optical system, the optical system converts a linear polarization distribution with a preferential polarization direction which is constant over a cross-section of a light beam into an approximately tangential polarization distribution.

15. The optical system of claim 1 , further comprising a polarization-influencing optical element comprising an optically active material having a varying thickness profile.

16. An apparatus, comprising:
an illumination system; and
a projection objective,
wherein the illumination system and/or the projection objective comprises an optical system according to claim 1 , and apparatus is a microlithographic projection exposure apparatus.

17. A method, comprising:
using an illumination system of a microlithographic projection exposure apparatus to illuminate a mask comprising structures; and
using a projection objective of the microlithographic projection exposure apparatus to image the structures of the mask onto a light-sensitive material,
wherein the illumination system and/or the projection objective comprises an optical system according to claim 1 .

18. The optical system of claim 1 , wherein neither first lambda/2 plate nor the second lambda/2 plate is downstream of the mirror arrangement along the light path that light follows through the optical system during use of the optical system.

19. A method of operating a microlithograpic projection exposure apparatus comprising an illumination system and a projection objective, the illumination system comprising a mirror arrangement and a polarization-influencing optical arrangement, the mirror arrangement comprising a plurality of mirror elements which are displaceable independently of each other to alter an angular distribution of light reflected by the mirror arrangement during use of the optical system, the polarization-influencing optical arrangement comprising first and second lambda/2 plates, the method comprising:
interacting light with the polarization-influencing optical arrangement when the first and second lambda/2 plates have a first relative position to provide a first illumination setting in a pupil plane of the illumination system; and
interacting light with the polarization-influencing optical arrangement when the first and second lambda/2 plates have a second relative position to provide a second illumination setting in the pupil plane of the illumination system,
wherein:
the first relative position is different from the second relative position;
the first and second lambda/2 plates are arranged so that they partially mutually overlap in a light propagation direction forming at least one overlap region and at least one non-overlap region;
the first and second lambda/2 plates are upstream of a pupil plane along a path that light follows through the illumination system during use of the illumination system; and
the first illumination setting in the pupil plane differs from the second illumination setting in the pupil plane.

20. The method of claim 19 , wherein both the overlap region and also the non-overlap region are at least partially illuminated.

21. The method of claim 19 , wherein at least two beam portions which are reflected by different mirror elements of the mirror arrangement of the illumination system and which have different polarization directions as a consequence of the action of the polarization-influencing arrangement are mutually superposed.

22. The method of claim 19 , wherein neither first lambda/2 plate nor the second lambda/2 plate is downstream of the mirror arrangement along the light path that light follows through the optical system during use of the optical system.

23. An optical system, comprising:
a mirror arrangement comprising a plurality of mirror elements which are displaceable independently of each other to alter an angular distribution of light reflected by the mirror arrangement during use of the optical system; and
a polarization-influencing optical arrangement comprising a

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Saenger Ingo
• Dittmann Olaf
• Zimmermann Joerg

Classifications

• G03F7/70566

  Polarisation control · CPC title

• G03F7/70116 Primary

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

• G03F7/26 Primary

  Processing photosensitive materials; Apparatus therefor (G03F7/12 - G03F7/24 take precedence) · CPC title

• G03F7/20

  Exposure; Apparatus therefor (photographic printing apparatus for making copies G03B27/00) · CPC title