Illumination system of a microlithographic projection exposure apparatus with a birefringent element

Patent metadata

Field	Value
Publication number	US-10151982-B2
Application number	US-201615008731-A
Country	US
Kind code	B2
Filing date	Jan 28, 2016
Priority date	Sep 14, 2007
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

The disclosure concerns an illumination system of a microlithographic projection exposure apparatus. The illumination system includes a mirror arrangement which has a plurality of mirror units and at least one element arranged in front of the mirror arrangement in the light propagation direction to produce at least two different states of polarization incident on different mirror units. The mirror units are displaceable independently of each other for altering an angle distribution of the light reflected by the mirror arrangement.

First claim

The invention claimed is:

1. An illumination system, comprising:
a mirror arrangement comprising a plurality of mirror units displaceable independently of each other to alter an angle distribution of light reflected by the mirror arrangement; and
an arrangement comprising first and second elements,
wherein:
the first element comprises a birefringent material;
the second element comprises a birefringent material;
a relative position of the first and second elements is variable;
the illumination system is configured so that adjusting respective positions of the first and second elements adjusts: a) a number and a position of mirror units that overlap with at least one of the first and second elements and b) a polarization distribution in a pupil plane of the illumination system during use of the illumination system;
the first and second elements are movable in two directions that are perpendicular to each other and perpendicular to a light propagation direction; and
the illumination system is a microlithographic illumination system.

2. The illumination system of claim 1 , wherein the first and second elements are independently movable in a plane perpendicular to a light propagation direction.

3. The illumination system of claim 1 , wherein the first and second elements are immediately upstream of a portion of the mirror arrangement.

4. The illumination system of claim 3 , wherein the illumination system is configured so that, during use of the illumination system, different polarization states existing in the light downstream of the arrangement are reflected by different mirror units and thereby directed to different positions of the pupil plane.

5. The illumination system of claim 1 , wherein the first and second elements are immediately downstream of a portion of the mirror arrangement.

6. The illumination system of claim 1 , wherein the first and second elements comprise retardation plates.

7. The illumination system of claim 6 , wherein the retardation plates have retardations of opposite sign.

8. The illumination system of claim 1 , wherein the first and second elements exhibit circular birefringence.

9. The illumination system of claim 8 , wherein the first and second elements have the same sign of optical rotation.

10. The illumination system of claim 8 , wherein the first and second elements have the opposite sign of optical rotation.

11. The illumination system of claim 8 , wherein the first and second elements comprise crystalline quartz.

12. The illumination system of claim 1 , wherein the first and second elements have a varying thickness profile measured in a light propagation direction.

13. The illumination system of claim 1 , wherein the first and second elements are wedge-shaped elements.

14. The illumination system of claim 13 , wherein one of the wedge-shaped elements comprises a light exit surface being structured according to a step function.

15. The illumination system of claim 1 , wherein the first and second elements comprise wedge-shaped elements with an optical crystal axis oriented in plane perpendicular to a light propagation and under 45° with respect to each other.

16. The illumination system of claim 1 , wherein the arrangement comprises a plurality of plane-parallel sections or blocks, and at least some of the blocks have a different thickness measured in a light propagation direction.

17. The illumination system of claim 13 , wherein the plurality of plane-parallel sections or blocks are monolithic.

18. The illumination system of claim 1 , wherein the first and second elements comprise plane-parallel elements.

19. The illumination system of claim 1 , further comprising a control device configured to move the first and second elements relative to each other.

20. The illumination system of claim 1 , wherein the illumination system is configured so that respective positions of the first and second elements are adjustable to compensate retardation produced by the optical components of the illumination system and/or birefringence introduced in the illumination system by a mask.

21. A method, comprising:
providing the illumination system of claim 1 ; and
adjusting respective positions of the first and second elements to compensate retardations produced by optical components of the illumination system and/or birefringence introduced in the system by a mask.

22. An apparatus, comprising:
an illumination system according to claim 1 ; and
a projection objective,
wherein the apparatus is a microlithographic projection exposure apparatus.

23. A method of using a microlithographic projection exposure apparatus comprising an illumination system and a projection objective, the method comprising:
using the illumination system to illuminate at least part of structures of a mask; and
using the projection objective to image at least part of the illuminated structures of the mask onto a light-sensitive material,
wherein the illumination system is an illumination system according to claim 1 .

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Fiolka Damian
• Walldorf Daniel
• Saenger Ingo

Classifications

• G03F7/70566

  Polarisation control · CPC title

• G03F7/70966

  Birefringence · CPC title

• G03F7/70191

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

• G03F7/2008 Primary

  characterised by the reflectors, diffusers, light or heat filtering means or anti-reflective means used · 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