Illumination optical assembly, exposure apparatus, and device manufacturing method

• US 10,578,973 B2
• Filed: 10/24/2016
• Issued: 03/03/2020
• Est. Priority Date: 10/24/2011
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Tanaka, Hirohisa, Ooki, Hiroshi, Nakajima, Shinichi
• Primary Examiner(s): Kim, Peter B
• Application Number:
  US15/332,890
• Publication Number:
  US 20170045824A1
• Time in Patent Office: 1,226 Days
• Field of Search: 355 71
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 5/3075 for use in the UV G02B5/3066 takes precedence
• 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
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

An illumination optical system can form a pupil intensity distribution with a desired beam profile. The illumination optical system for illuminating an illumination target surface with light from a light source is provided with a spatial light modulator which has a plurality of optical elements arrayed on a predetermined surface and individually controlled and which variably forms a light intensity distribution on an illumination pupil of the illumination optical system; a divergence angle providing member which is arranged in a conjugate space including a surface optically conjugate with the predetermined surface and which provides a divergence angle to an incident beam and emits the beam; and a polarizing member which is arranged at a position in the vicinity of the predetermined surface or in the conjugate space and which changes a polarization state of a partial beam of a propagating beam propagating in an optical path.

Claims

1. An illumination optical system which illuminates an illumination target surface with light, the illumination optical system comprising:

an optical integrator disposed in an optical path of the light on an incidence side of an illumination pupil of the illumination optical system;

a spatial light modulator having a plurality of optical elements arranged along a predetermined surface, the plurality of optical elements being disposed in the optical path of the light on an incidence side of the optical integrator;

an optical member disposed in the optical path of the light on an incidence side of the plurality of optical elements or between the plurality of optical elements and the optical integrator, the optical member being configured to variably set at least one of sizes and intensities of beams on the illumination pupil, the beams being at least a part of the light being distributed on the illumination pupil by the spatial light modulator; and

an imaging optical system arranged in the optical path of the light between the plurality of optical elements and the optical member,

wherein the optical member is located in a conjugate space in which a conjugate plane is located, the conjugate plane being a plane conjugate with the predetermined surface through the imaging optical system, and

wherein the optical member acts on at least a portion of the light such that the light includes a first beam and a second beam, the first beam having a first divergence angle, the second beam having a second divergence angle different from the first divergence angle, the first beam and the second beam being distributed at different positions on the illumination pupil.

2. The illumination optical system according to claim 1, wherein the plurality of optical elements and the optical member are substantially conjugate with each other through the imaging optical system.

3. The illumination optical system according to claim 1, wherein the optical member includes at least one of refractive, reflective and diffractive optical elements.

4. The illumination optical system according to claim 3, wherein the at least one of refractive, reflective and diffractive optical elements are arranged in an array along a plane intersecting the optical path.

5. The illumination optical system according to claim 1, wherein the optical member is configured to transform each divergence angle of at least part of the beams.

6. The illumination optical system according to claim 1, wherein the plurality of optical elements are mirrors each of which has a variably controllable posture or height relative to the predetermined surface.

7. An exposure apparatus which exposes a substrate with light from a pattern on a first plane, the exposure apparatus comprising:

the illumination optical system according to claim 1 which illuminates the pattern; and

a projection optical system which projects an image of the pattern illuminated with the light from the illumination optical system onto the substrate.

8. The exposure apparatus according to claim 7, wherein the illumination optical system is arranged so that the illumination pupil is located at a position optically conjugate with an aperture stop of the projection optical system.

9. A device manufacturing method comprising:

performing exposure of a substrate by using of the exposure apparatus according to claim 7; and

developing the substrate exposed with the exposure apparatus.