Optical assembly for increasing the etendue

Patent metadata

Field	Value
Publication number	US-9678432-B2
Application number	US-201514828603-A
Country	US
Kind code	B2
Filing date	Aug 18, 2015
Priority date	Mar 14, 2013
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

An optical system has a light source having an original etendue of less than 0.1 mm 2 for an illumination system for projection lithography. An optical assembly serves for simultaneously increasing the etendue of a used emission of the light source. The optical assembly is embodied such that an increase in the etendue by at least a factor of 10 results. A component of the optical assembly that is impinged on is displaced relative to the light source such that an impingement region of the emission of the light source on the optical component of the optical assembly varies temporally.

First claim

The invention claimed is:

1. An optical system, comprising:
a light source configured to emit light having an original etendue of less than 0.1 mm 2 ; and
an optical assembly, comprising:
an optical component; and
a medium,

wherein the optical assembly is configured so that, during use of the optical system:
the medium scatters light emitted by the light source to simultaneously increase an etendue of the light by at least a factor of 10;
the light impinges on the optical component; and
the optical component is displaced so that an impingement region of the light on the optical component of the optical assembly varies temporally.

2. The optical system of claim 1 , wherein:
the optical assembly comprises a scattering particle generator configured to generate scattering particles;
the medium comprises the scattering particles; and
the optical assembly is configured so that, during use of the optical system, the scattering particles interact with the emission of the light source to increase the etendue of the used emission of the light source.

3. The optical system of claim 2 , wherein:
the scattering particle generator comprises a raw particle generation device and a scattering particle dispersing device; and
the scattering particle generator is configured so that, during use of the optical system, raw particles initially generated in the raw particle generation device are dispersed to form the scattering particles via the scattering particle dispersing device.

4. The optical system of claim 2 , further comprising a collecting device configured so that, during use of the optical system, the collecting device collects the scattering particles in their trajectory after their interaction with the emission of the light source.

5. The optical system of claim 1 , further comprising a drive device, wherein:
the optical component comprises a body;
the medium comprises etendue-increasing structures at a surface of the body; and
the optical component and the drive device are configured so that, during use of the optical system, the optical component cooperates with the drive device to displace the optical component to temporally vary the impingement region.

6. The optical system of claim 5 , wherein the drive device is configured so that, during use of the optical system, the drive device causes a periodic displacement of the optical component and/or aperiodic displacement of the optical component.

7. The optical system of claim 5 , wherein the drive device is configured so that, during use of the optical system, the drive device performs a driven displacement so that a main deflection direction of the optical component does not change.

8. The optical system of claim 5 , wherein the optical component comprises a deflection mirror.

9. An optical system, comprising:
an optical assembly, comprising:
an optical component; and
a medium,

wherein the optical assembly is configured so that, during use of the optical system:
the medium scatters light emitted by a light source to simultaneously increase an etendue of the light by at least a factor of 10;
light impinges on the optical component; and
the optical component is displaced so that an impingement region of the light on the optical component of the optical assembly varies temporally; and

an illumination optical unit downstream of the optical assembly along a path of light through the optical system, the illumination optical unit configured to illuminate an object field.

10. The optical system of claim 9 , wherein the optical system has an intermediate focus downstream of the optical assembly.

11. The optical system of claim 9 , further comprising a free electron laser configured to generate the light.

12. The optical system of claim 9 , further comprising the light source, wherein the light source is configured to emit light having an original etendue of less than 0.1 mm 2 .

13. The optical system of claim 12 , wherein the light source comprises a free electron laser.

14. The optical system of claim 9 , wherein:
the optical assembly comprises a scattering particle generator configured to generate scattering particles;
the medium comprises the scattering particles; and
the optical assembly is configured so that, during use of the optical system, the scattering particles interact with the emission of the light source to increase the etendue of the used emission of the light source.

15. The optical system of claim 9 , further comprising a drive device, wherein:
the optical component comprises a body;
the medium comprises etendue-increasing structures at a surface of the body; and
the optical component and the drive device are configured so that, during use of the optical system, the optical component cooperates with the drive device to displace the optical component to temporally vary the impingement region.

16. An apparatus, comprising:
an optical assembly, comprising:
an optical component; and
a medium,

wherein the optical assembly is configured so that, during use of the optical system:
the medium scatters light emitted by a light source to simultaneously increase an etendue of the light by at least a factor of 10;
light impinges on the optical component; and
the optical component is displaced so that an impingement region of the light on the optical component of the optical assembly varies temporally;

an illumination optical unit downstream of the optical assembly along a path of light through the apparatus, the illumination optical unit configured to illuminate an object field; and
a projection optical unit configured to image an object in the object field into an image field, wherein the apparatus is a lithography projection exposure apparatus.

17. The apparatus of claim 16 , further comprising the light source, wherein the light source is configured to emit light having an original etendue of less than 0.1 mm 2 .

18. The apparatus of claim 17 , wherein the light source comprises a free electron laser.

19. The apparatus of claim 16 , wherein:
the optical assembly comprises a scattering particle generator configured to generate scattering particles;
the medium comprises the scattering particles; and
the optical assembly is configured so that, during use of the optical system, the scattering particles interact with the emission of the light source to increase the etendue of the used emission of the light source.

20. The apparatus of claim 16 , further comprising a drive device, wherein:
the optical component comprises a body;
the medium comprises etendue-increasing structures at a surface of the body; and
the optical component and the drive device are configured so that, during use of the optical system, the optical component cooperates with the drive device to displace the optical component to temporally vary the impingement region.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Saenger Ingo
• Hennerkes Christoph

Classifications

• G21K1/067

  using surface reflection, e.g. grazing incidence mirrors, gratings (multilayer mirrors G21K1/062) · CPC title

• G03F7/70033 Primary

  by plasma extreme ultraviolet [EUV] sources · 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

• G03F7/70191

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

• G21K1/065

  using refraction, e.g. Tomie lenses · CPC title