Facet mirror for an illumination optical unit of a projection exposure apparatus

Patent metadata

Field	Value
Publication number	US-11789367-B2
Application number	US-202217695402-A
Country	US
Kind code	B2
Filing date	Mar 15, 2022
Priority date	Sep 19, 2019
Publication date	Oct 17, 2023
Grant date	Oct 17, 2023

Abstract

A facet mirror for an illumination optical unit of a projection exposure apparatus has a large number of displaceable individual facets with a facet main body and a reflection surface arranged on it. At least some of the individual facets have a displacement range such that they come into contact with a stop surface in one or more displacement positions.

First claim

What is claimed is:

1. A facet mirror, comprising:
a plurality of displaceable individual facets, each facet comprising:
a facet main body comprising at least one member selected from the group consisting of stop surfaces and stop elements; and
a reflection surface supported by the main body,

wherein:
the individual facets comprise a first facet and a second facet;
relative to an edge of the reflection surface of the first facet, the at least one member of the main body of the first facet is offset outwardly in a direction perpendicular to a tilting axis of the first facet;
relative to an edge of the reflection surface of the second facet, the at least one member of the main body of the second facet is offset outwardly in a direction perpendicular to a tilting axis of the second facet;
in a first position of the facet mirror, the first and second facets do not contact each other; and
in a second position of the facet mirror, the at least one member of the first facet contacts the main body of the second facet without the edge of the reflection surface of the first facet contacting the edge of the reflection surface of the second facet.

2. The facet mirror of claim 1 , wherein, for each of the first and second facets, when the facet mirror is in its first position and/or its second position, the facet is a distance from the at least one member of all other facets.

3. The facet mirror of claim 1 , wherein, for each facet of the first and second facets, the facet has a displacement range such that adjacent individual facets contact the facet in at least one displacement position.

4. The facet mirror of claim 1 , wherein, for each facet of the first and second facets, the facet is configured so that adjacent individual facets have a position in which they come into contact in an area of at least one member of the facet.

5. The facet mirror of claim 1 , wherein, for each facet of the first and second facets, the at least one member comprises stop surfaces.

6. The facet mirror of claim 1 , wherein, for each facet of the first and second facets, the at least one member comprises stop elements.

7. The facet mirror of claim 1 , wherein:
for each facet of the first and second facets, the at least one member comprises a stop element;
the stop elements of the first and second facets define a pair on the facet main body such that its outer envelope protrudes beyond the reflection surface in a direction in a perpendicular projection to a partial area of the reflection surface enclosed by the envelope; and
in the second position of the facet mirror, the stop elements of the first and second facets contact each other without the edge of the reflection surface of the first facet contacting the edge of the reflection surface of the second facet.

8. The facet mirror of claim 1 , further comprising a mechanism configured to limit a displacement range of the individual facets.

9. A unit, comprising:
the facet mirror of claim 1 ,
wherein the unit is an illumination optical unit.

10. A system, comprising:
a radiation source configured to produce illumination radiation; and
an illumination optical unit comprising the facet mirror of claim 1 ,
wherein the system is an illumination system.

11. A system, comprising:
an illumination optical unit comprising the facet mirror of claim 1 , the illumination optical unit configured to illuminate an object field; and
a projection optical unit configured to project the object field into an image field,
wherein the system is an optical system.

12. An apparatus, comprising:
a radiation source configured to produce illumination radiation;
an illumination optical unit comprising the facet mirror of claim 1 , the illumination optical unit configured to illuminate an object field with the illumination radiation; and
a projection optical unit configured to project the object field into an image field,
wherein the apparatus is a projection exposure apparatus.

13. A method of using a projection exposure apparatus comprising an illumination optical unit and a projection optical unit, the method comprising:
using the illumination optical unit to illuminate an image field with illumination radiation; and
using the projection optical unit to project the image field into an object field,
wherein the illumination optical unit comprises a facet mirror according to claim 1 .

14. The facet mirror of claim 1 , wherein, in the second position of the facet mirror, the at least one member of the first facet contacts the at least one member of the second facet without the edge of the reflection surface of the first facet contacting the edge of the reflection surface of the second facet.

15. The facet mirror of claim 1 , wherein:
the at least one member of the first facet comprises a first stop element;
in the second position of the facet mirror, the first stop element contacts the main body of the second facet without the edge of the reflection surface of the first facet contacting the edge of the reflection surface of the second facet.

16. The facet mirror of claim 1 , wherein:
the at least one member of the first facet comprises a first stop element;
the at least one member of the second facet comprises a second stop element;
in the second position of the facet mirror, the first stop element contacts the second stop element without the edge of the reflection surface of the first facet contacting the edge of the reflection surface of the second facet.

17. The facet mirror of claim 16 , wherein the first stop element is rounded or chamfered, and the second stop element is rounded or chamfered.

18. The facet mirror of claim 1 , wherein the at least one member of the main body of the first facet is rounded or chamfered, and the at least one member of the main body of the second facet is rounded or chamfered.

19. The facet mirror of claim 1 , wherein:
the at least one member of the first facet comprises a first stop surface;
in the second position of the facet mirror, the first stop surface contacts the main body of the second facet without the edge of the reflection surface of the first facet contacting the edge of the reflection surface of the second facet.

20. The facet mirror of claim 1 , wherein:
the at least one member of the first facet comprises a first stop surface;
the at least one member of the second facet comprises a second stop surface;
in the second position of the facet mirror, the first stop surface contacts the second stop surface without the edge of the reflection surface of the first facet contacting the edge of the reflection surface of the second facet.

21. The facet mirror of claim 1 , wherein the reflection surface is configured to reflect EUV radiation.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Anderl Willi
• Körner Christian
• Holderer Hubert
• Holz Markus
• Stompe Manuel
• Seitz Stefan

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

• G03F7/702

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

• G03F7/70983

  Optical system protection, e.g. pellicles or removable covers for protection of mask · 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