Illumination device

• US 10,459,343 B2
• Filed: 11/15/2018
• Issued: 10/29/2019
• 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:
  US16/192,208
• Publication Number:
  US 20190086812A1
• Time in Patent Office: 348 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 direct the condensed light beams onto the pattern surface; and

a light intensity distribution changing member arranged on an optical path between the light source and the fly'"'"'s eye optical system, the light intensity distribution changing member being configured to change a first light amount of a first light beam with respect to a second light amount of a second light beam, while causing the first light beam to enter at a first position on one optical surface of the plurality of optical surfaces of the fly'"'"'s eye optical system and causing the second light beam to enter at a second position located on the one optical surface and different from the first position.

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

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

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

the light intensity distribution changing member deflects at least one of the first light beam and the second light beam.

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

the light intensity distribution changing member applies a first refracting operation to an incident light beam reaching a first position on the light intensity distribution changing 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 changing 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.

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

the light intensity distribution changing 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.

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

the light intensity distribution changing 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.

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

the light intensity distribution changing 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.

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

the light intensity distribution changing 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.

9. 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.

10. An exposure method 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,

wherein in the illuminating, the pattern positioned on the pattern surface is illuminated by using the illumination optical system as set forth in claim 1.

11. A device manufacturing method comprising:

performing exposure to transfer an exposure pattern onto the workpiece, using the exposure method as set forth in claim 10;

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.

12. 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 directing the condensed light beams onto the pattern surface, by using a condenser optical system; and

using a light intensity distribution changing member arranged on an optical path between the light source and the fly'"'"'s eye optical system to change a first light amount of a first light beam with respect to a second light amount of a second light beam, while causing the first light beam to enter at a first position on one optical surface of the plurality of optical surfaces of the fly'"'"'s eye optical system, and the second light beam to enter at a second position located on the one optical surface and different from the first position.

13. The illumination method according to claim 12, further including

directing the first light beam and the second light beam from the fly'"'"'s eye optical system at different positions on the pattern surface, by using the condenser optical system.

14. The illumination method according to claim 12, wherein

the changing includes deflecting one of the first light beam and the second light beam by using the light intensity distribution changing member.

15. The illumination method according to claim 12, wherein

the changing, by using the light intensity distribution changing member, includes:

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

16. The illumination method according to claim 12, wherein

the changing, by using the light intensity distribution changing member, includes causing 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.

17. The illumination method according to claim 12, wherein

the changing includes changing a position of the light intensity distribution changing member to change each light intensity distribution of the plurality of optical surfaces of the fly'"'"'s eye optical system.

18. The illumination method according to claim 12, wherein

the changing, by using the light intensity distribution changing member, includes 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.

19. The illumination method according to claim 18, wherein

the changing, by using the light intensity distribution changing member, 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 light amount 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.

20. An exposure method using the illumination method as set forth in claim 12, 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.

21. A device manufacturing method comprising:

performing exposure to transfer an exposure pattern onto the workpiece, using the exposure method as set forth in claim 20;

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.