Illumination device

• US 10,162,269 B2
• Filed: 08/11/2017
• Issued: 12/25/2018
• Est. Priority Date: 08/04/2011
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Komatsuda, Hideki
• Primary Examiner(s): Iacoletti, Michelle M
• Application Number:
  US15/675,257
• Publication Number:
  US 20170343902A1
• Time in Patent Office: 501 Days
• Field of Search: None
• CPC Class Codes: G03F 7/70058 Mask illumination systems
• CPC Class Codes: G03F 7/70075 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 Class Codes: G03F 7/70091 Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]
• CPC Class Codes: G03F 7/70191 Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like

Abstract

An object is to provide an illumination apparatus that achieves illumination with a uniform illuminance distribution, while reducing a light quantity loss. An illumination apparatus for illuminating an illumination target surface has: a deflection member configured to form an illuminance distribution with a periodic pattern along a predetermined direction on a predetermined face traversing an optical path; and an optical integrator system having a plurality of wavefront division facets arrayed on the predetermined face and configured to form secondary light sources with use of a beam from the deflection member; the deflection member forms the illuminance distribution with the periodic pattern of an integer times or a unit fraction times an array period of the plurality of wavefront division facets.

Claims

1. An illumination optical system which illuminates a pattern surface with light from a light source and is capable of being applied to an exposure apparatus for exposing an image of a pattern arranged on the pattern surface onto a workpiece, the illumination optical system comprising:

a fly'"'"'s eye optical system having a plurality of optical surfaces arranged on a surface crossing an optical path of the light from the light source;

a condenser optical system configured to condense a plurality of light beams respectively passing through the plurality of optical surfaces of the fly'"'"'s eye optical system and guide the condensed light beams onto the pattern surface; and

a light intensity distribution setting member arranged on an optical path between the light source and the fly'"'"'s eye optical system, the light intensity distribution setting member configured to cause a difference between a first light amount of a first light beam and a second light amount of a second light beam, the first light beam entering at a first position on one optical surface out of the plurality of optical surfaces of the fly'"'"'s eye optical system, the second light beam entering at a second position on the one optical surface,

wherein the condenser optical system guides the first and second light beams from the fly'"'"'s eye optical system at different positions on the pattern surface.

2. The illumination optical system according to claim 1, wherein

the light intensity distribution setting member deflects the light from the light source so that the first light amount and the second light amount differ from each other.

3. The illumination optical system according to claim 1, wherein

the light intensity distribution setting member applies a first refracting operation to an incident light beam reaching a first position on the light intensity distribution setting member, and applies a second refracting operation different from the first refracting operation to an incident light beam reaching a second position on the light intensity distribution setting member, the first refracting operation causing such a state that the first light beam enters at the first position on the one optical surface, the second refracting operation causing such a state that the second light beam enters at the second position on the one optical surface.

4. The illumination optical system according to claim 1, wherein

the light intensity distribution setting member causes a difference between a pupil intensity distribution relevant to an incident light beam reaching a first position on the pattern surface and a pupil intensity distribution relevant to an incident light beam reaching a second position on the pattern surface.

5. The illumination optical system according to claim 1, wherein

the light intensity distribution setting member is changed in a position thereof to change each light intensity distribution of the plurality of optical surfaces of the fly'"'"'s eye optical system.

6. The illumination optical system according to claim 1, wherein

the light intensity distribution setting member causes a difference between a first intensity distribution of an incident light beam reaching a first optical surface and a second intensity distribution of an incident light beam reaching a second optical surface, the first optical surface corresponding to the one optical surface, the first and second optical surfaces being different from each other and included in the plurality of optical surfaces of the fly'"'"'s eye optical system.

7. The illumination optical system according to claim 6, wherein

the light intensity distribution setting member sets the first intensity distribution so that a light amount of a third light beam entering at a third position on the first optical surface and a light amount a fourth light beam entering at a fourth position on the first optical surface are different from each other, and sets the second intensity distribution so that a light amount of a fifth light beam entering at a fifth position on the second optical surface and a light amount of a sixth light beam entering at a sixth position on the second optical surface are different from each other, the fourth position being different from the third position, the sixth position being different from the fifth position.

8. An exposure apparatus comprising the illumination optical system as set forth in claim 1, and configured to expose the workpiece with light through the pattern positioned on the pattern surface.

9. An exposure method using the illumination optical system as set forth in claim 1, comprising:

illuminating the pattern arranged on the pattern surface with the light from the light source; and

exposing the workpiece with light through the pattern.

10. A device manufacturing method comprising:

performing exposure to transfer an exposure pattern onto the workpiece, using the exposure method as set forth in claim 9;

developing the workpiece onto which the exposure pattern has been transferred, to form a mask layer in a shape corresponding to the exposure pattern on a surface of the workpiece; and

processing the surface of the workpiece through the mask layer.

11. An illumination method which illuminates a pattern surface with light from a light source and is used for exposing an image of a pattern arranged on the pattern surface onto a workpiece, the illumination method comprising:

illuminating a fly'"'"'s eye optical system with the light from the light source, the fly'"'"'s eye optical system having a plurality of optical surfaces arranged on a surface crossing an optical path of the light from the light source;

condensing a plurality of light beams respectively passing through the plurality of optical surfaces of the fly'"'"'s eye optical system and guiding the condensed light beams onto the pattern surface; and

causing a difference between a first light amount of a first light beam and a second light amount of a second light beam, the first light beam entering at a first position on one optical surface out of the plurality of optical surfaces of the fly'"'"'s eye optical system, the second light beam entering at a second position on the one optical surface,

wherein the guiding the condensed light beams includes guiding the first and second light beams from the fly'"'"'s eye optical system at different positions on the pattern surface.

12. The illumination method according to claim 11, wherein

the causing the difference between the first and second light amounts includes:

applying a first refracting operation to an incident light beam reaching a first position on a predetermined surface positioned between the light source and the fly'"'"'s eye optical system, the first refracting operation causing such a state that the first light beam enters at the first position on the one optical surface, and

applying a second refracting operation different from the first refracting operation to an incident light beam reaching a second position on the predetermined surface, the second refracting operation causing such a state that the second light beam enters at the second position on the one optical surface.

13. The illumination method according to claim 11, wherein

the causing the difference between the first and second light amounts causes a difference between a pupil intensity distribution relevant to an incident light beam reaching a first position on the pattern surface and a pupil intensity distribution relevant to an incident light beam reaching a second position on the pattern surface.

14. The illumination method according to claim 11, wherein

the causing the difference between the first and second light amounts includes changing each light intensity distribution of the plurality of optical surfaces of the fly'"'"'s eye optical system.

15. The illumination method according to claim 11, further comprising

causing a difference between a first intensity distribution of an incident light beam reaching a first optical surface and a second intensity distribution of an incident light beam reaching a second optical surface, the first optical surface corresponding to the one optical surface, the first and second optical surfaces being different from each other and included in the plurality of optical surfaces of the fly'"'"'s eye optical system.

16. The illumination method according to claim 15, wherein

the causing the difference between the first and second intensity distributions includes:

setting the first intensity distribution so that a light amount of a third light beam entering at a third position on the first optical surface and a fourth light beam entering at a fourth position on the first optical surface are different from each other, and

setting the second intensity distribution so that a light amount of a fifth light beam entering at a fifth position on the second optical surface and a light amount of a sixth light beam entering at a sixth position on the second optical surface are different from each other, the fourth position being different from the third position, the sixth position being different from the fifth position.

17. An exposure method using the illumination method as set forth in claim 11, comprising:

illuminating the pattern arranged on the pattern surface with the light from the light source; and

exposing the workpiece with light through the pattern.

18. A device manufacturing method comprising:

performing exposure to transfer an exposure pattern onto the workpiece, using the exposure method as set forth in claim 17;

developing the workpiece onto which the exposure pattern has been transferred, to form a mask layer in a shape corresponding to the exposure pattern on a surface of the workpiece; and

processing the surface of the workpiece through the mask layer.