Illumination optical assembly, exposure device, and device manufacturing method

• US 10,353,294 B2
• Filed: 12/14/2016
• Issued: 07/16/2019
• Est. Priority Date: 06/13/2011
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Miyake, Norio, Kato, Kinya
• Primary Examiner(s): Persaud, Deoram
• Application Number:
  US15/378,582
• Publication Number:
  US 20170090297A1
• Time in Patent Office: 944 Days
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G03F 7/20 Exposure; Apparatus therefor photographic printing apparatus for making copies G03B27/00
• 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 7/70116 Off-axis setting using a programmable means, e.g. liquid crystal display [LCD], digital micromirror device [DMD] or pupil facets
• CPC Class Codes: G03F 7/7015 Details of optical elements
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

An illumination optical system includes a fly'"'"'s-eye lens having a back focal plane arranged on a pupil plane of the illumination optical system or in a vicinity of the pupil plane; a first spatial light modulator which is arranged on an incident side of the fly'"'"'s-eye lens and which includes a plurality of first mirror elements; a first optical system arranged in an optical path between the first spatial light modulator and the fly'"'"'s-eye lens; a second spatial light modulator arranged in an optical path between the first optical system and the fly'"'"'s-eye lens and which includes a plurality of second mirror elements; and a polarizing element arranged in the optical path between the first spatial light modulator and the fly'"'"'s-eye lens.

Claims

1. An illumination optical system for illuminating an object with an illumination light, the illumination optical system comprising:

a fly'"'"'s-eye lens of which back focal plane is arranged on a pupil plane of the illumination optical system or in a vicinity of the pupil plane, the pupil plane being in a substantially optical Fourier transform relation with a predetermined plane on which the object is to be arranged;

a first spatial light modulator which is arranged on an incident side of the fly'"'"'s-eye lens and which includes a plurality of first mirror elements;

a first optical system arranged in an optical path between the first spatial light modulator and the fly'"'"'s-eye lens,

a second spatial light modulator which is arranged in an optical path between the first optical system and the fly'"'"'s-eye lens and which includes a plurality of second mirror elements, the first optical system creating a substantially optical Fourier transform relation between the plurality of first mirror elements of the first spatial light modulator and the plurality of second mirror elements of the second spatial light modulator; and

a polarizing element arranged in the optical path between the first spatial light modulator and the fly'"'"'s-eye lens.

2. The illumination optical system according to claim 1, wherein the polarizing element is arranged at a position conjugate with the pupil plane or in a vicinity of the position.

3. The illumination optical system according to claim 2, wherein the polarizing element is made of an optical material having an optical activity and is arranged such that an optic axis of the polarizing element is substantially identical to an optical axis of the illumination optical system.

4. The illumination optical system according to claim 2, further comprising:

a second optical system arranged on an incident side of the first spatial light modulator; and

a third optical system arranged in an optical path between the second spatial light modulator and the fly'"'"'s-eye lens,

wherein the second and third optical systems are arranged such that an optical axis of the second optical system and an optical axis of the third optical system are substantially parallel to each other.

5. The illumination optical system according to claim 4, further comprising:

a first mirror arranged in an optical path between the third optical system and the fly'"'"'s-eye lens;

a second mirror arranged in an optical path between the fly'"'"'s-eye lens and the predetermined plane; and

a fourth optical system arranged in an optical path between the first and second mirrors and includes the fly'"'"'s-eye lens,

wherein the fourth optical system is arranged such that an optical axis of the fourth optical system is substantially orthogonal to the optical axis of the second optical system and the optical axis of the third optical system.

6. The illumination optical system according to claim 1, wherein the polarizing element is arranged in an optical path between the second spatial light modulator and the fly'"'"'s-eye lens, and the second spatial light modulator guides the illumination light to the polarizing element such that a first portion of the illumination light comes into a first region of the polarizing element and a second portion of the illumination light comes into a second region of the polarizing element, the first and second regions being different from each other.

7. An exposure apparatus for exposing a substrate with an illumination light, the exposure apparatus comprising:

the illumination optical system as defined in claim 1 that illuminates a mask with the illumination light; and

a projection optical system which forms a pattern image of the mask onto the substrate,

wherein a pupil plane of the illumination optical system and a pupil plane of the projection optical system are arranged substantially conjugate with each other.

8. A device manufacture method comprising:

exposing a substrate by using the exposure apparatus as defined in claim 7; and

developing the exposed substrate.

9. A manufacturing method of an exposure apparatus for exposing a substrate with an illumination light, the manufacturing method comprising:

providing the illumination optical system as defined in claim 1 that illuminates a mask with the illumination light; and

providing a projection optical system which forms a pattern image of the mask onto the substrate,

wherein a pupil plane of the illumination optical system and a pupil plane of the projection optical system are arranged substantially conjugate with each other.

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

at least one of the first and second spatial light modulators is capable of changing an intensity distribution, of the illumination light, on the pupil plane, and is capable of forming the intensity distribution, on the pupil plane, in which at least a portion of the illumination light is distributed to an off-axis region deviated from an optical axis of the illumination optical system, and

the polarizing element changes a polarization state of the illumination light coming into the polarizing element with the polarization state in which a linearly polarized light having a polarization direction in a predetermined direction is a main component such that the at least a portion of the illumination light, in the off-axis region, is linearly polarized light having a polarizing direction in a circumferential direction around the optical axis, to make the at least the portion of the illumination light illuminated on the object via the off-axis region have a polarization state in which s-polarized light is a main component.

11. The illumination optical system according to claim 10, wherein the polarizing element is arranged in an optical path between the first and second spatial light modulators, and the first spatial light modulator guides the illumination light to the polarizing element such that a first portion of the illumination light comes into a first region of the polarizing element and a second portion of the illumination light comes into a second region of the polarizing element, the first and second regions being different from each other.

12. An exposure method for exposing a substrate with an illumination light via a mask, the exposure method comprising:

forming, on a pupil plane of an illumination optical system, an intensity distribution, of the illumination light, in which at least a portion of the illumination light is distributed in an off-axis region deviated from an optical axis of the illumination optical system by using at least one of a first spatial light modulator and a second spatial light modulator, to illuminate the mask with the illumination light via the illumination optical system including a fly'"'"'s-eye lens of which back focal plane is arranged on the pupil plane or in a vicinity of the pupil plane, the pupil plane having a substantially optical Fourier transform relation with a predetermined plane on which the mask is to be arranged, the first and second spatial light modulators being arranged on an incident side of the fly'"'"'s-eye lens and each having a plurality of mirror elements, the illumination light transmits through a first optical system via the first spatial light modulator being distributed on the pupil plane by transmitting through the fly'"'"'s-eye lens via the second spatial light modulator, the first optical system creating a substantially optical Fourier transform relation between the plurality of mirror elements of the first spatial light modulator and the plurality of mirror elements of the second spatial light modulator,

changing, by using a polarizing element arranged in an optical path between the first spatial light modulator and the fly'"'"'s-eye lens, a polarization state of the illumination light coming into the polarizing element with the polarization state in which a linearly polarized light having a polarization direction in a predetermined direction is a main component such that the at least a portion of the illumination light, in the off-axis region, is linearly polarized light having a polarizing direction in a circumferential direction around the optical axis, to make the at least the portion of the illumination light illuminated on the mask via the off-axis region have a polarization state in which s-polarized light is a main component; and

forming a pattern image of the mask on the substrate via a projection optical system of which pupil plane is arranged substantially conjugate with the pupil plane of the illumination optical system.

13. The exposure method according to claim 12, wherein the polarizing element is arranged on a position conjugate with the pupil plane or in a vicinity of the position.

14. A device manufacture method comprising:

exposing a substrate by using the exposure method as defined in claim 12; and

developing the exposed substrate.