# US 10,120,291 B2 · Polarization-modulating element, illumination optical apparatus, exposure apparatus, and exposure method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,120,291 B2 - Document ID: US10120291B2 - Status: Granted - Kind: B2 - Application number: 13/912,832 - Filed: 2013-06-07 - Published: 2013-10-17 - Granted: 2018-11-06 - Earliest claimed: 2004-02-06 - Assignees: Nikon Corporation - Applicants: Nikon Corporation - Inventors: Osamu Tanitsu; Koji Shigematsu; Hiroyuki Hirota; Tomoyuki Matsuyama - Web page: https://patentgrep.com/patent/US10120291B2 ## CPC - G03F 7/70566: {Polarisation control} - F21V 9/14: for producing polarised light - F21V 13/02: Combinations of only two kinds of elements - 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)} - G03F 7/701: {Off-axis setting using an aperture} - G03F 7/70191: {Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like} - G03F 7/70308: {Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift} - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) - F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract There is disclosed a polarization-modulating element for modulating a polarization state of incident light into a predetermined polarization state, the polarization-modulating element being made of an optical material with optical activity and having a circumferentially varying thickness profile. ## Claims ### Claim 1 An illumination optical apparatus which illuminates an object with illumination light, the illumination optical apparatus comprising: a fly's eye lens arranged in an optical path of the illumination light so that a rear focal plane of the fly's eye lens is substantially located on an illumination pupil plane of the illumination optical apparatus; a polarization modulator made of an optical material with optical activity and provided with an uneven profile on at least one of an entrance surface and an exit surface of the polarization modulator such that the polarization modulator has different thicknesses of the optical material with respect to different positions on the entrance surface, the polarization modulator being arranged in the optical path on an incidence side of the fly's eye lens such that a direction of an optic axis of the optical material is substantially coincident with a direction of an optical axis of the illumination optical apparatus; and a plurality of optical elements arranged in the optical path on the incidence side of the fly's eye lens, the plurality of optical elements being movable relative to each other and modulating a light intensity distribution of the illumination light on the illumination pupil plane by moving the plurality of optical elements relative to each other; wherein the polarization modulator rotates a polarization direction of the illumination light and forms a linearly polarized state of the illumination light on the illumination pupil plane by rotating the polarization direction of the illumination light, the linearly polarized state having polarization directions being substantially coincident with an azimuthal direction about the optical axis or a radial direction centered around the optical axis on the illumination pupil plane. ### Claim 2 (depends on 1) The illumination optical apparatus according to claim 1, further comprising an optical system including a lens element arranged in the optical path of the illumination light from the fly's eye lens, which irradiates the object with the illumination light from the fly's eye lens in a polarization state in which a principal component is S-polarized light with respect to the object. ### Claim 3 (depends on 1) The illumination optical apparatus according to claim 1, wherein a first thickness of the polarization modulator in an optical path of a first part of the illumination light is different from a second thickness of the polarization modulator in an optical path of a second part of the illumination light, and the first part of the illumination light passes through a first portion of the pupil plane away from the optical axis, and the second part of the illumination light passes through a second portion of the illumination pupil plane away from the optical axis, the first and second portions being different from each other. ### Claim 4 (depends on 3) The illumination optical apparatus according to claim 3, further comprising a polarization state converter arranged in the optical path on an incidence side of the polarization modulator, wherein the polarization state converter converts a polarization state of the illumination light from a first polarization state including a substantially single polarization into a second polarization state different from the first polarization state. ### Claim 5 (depends on 4) The illumination optical apparatus according to claim 4, wherein a principal component of the second polarization state is linearly polarized light polarized substantially in the single direction. ### Claim 6 (depends on 4) The illumination optical apparatus according to claim 4, wherein a principal component of the first polarization state is linearly polarized light, circularly polarized light or elliptically polarized light. ### Claim 7 (depends on 4) The illumination optical apparatus according to claim 4, wherein the polarization state converter comprises at least one of a half wavelength plate and a quarter wavelength plate. ### Claim 8 (depends on 4) The illumination optical apparatus according to claim 4, wherein the first and second portions are included in an annular region about the optical axis. ### Claim 9 (depends on 4) The illumination optical apparatus according to claim 4, wherein the first and second portions are substantially discrete from each other and are aligned along a circumference about the optical axis. ### Claim 10 (depends on 3) The illumination optical apparatus according to claim 3, wherein the first and second portions are included in an annular region about the optical axis. ### Claim 11 (depends on 10) The illumination optical apparatus according to claim 10, wherein the first and second portions are substantially discrete from each other. ### Claim 12 (depends on 3) The illumination optical apparatus according to claim 3, wherein the first and second portions are substantially discrete from each other and are aligned along a circumference about the optical axis. ### Claim 13 (depends on 1) The illumination optical apparatus according to claim 1, further comprising a polarization state converter arranged in the optical path on an incidence side of the polarization modulator, wherein the polarization state converter converts a polarization state of the illumination light from a first polarization state including a substantially single polarization into a second polarization state different from the first polarization state. ### Claim 14 (depends on 13) The illumination optical apparatus according to claim 13, wherein a principal component of the second polarization state is linearly polarized light polarized substantially in the single direction. ### Claim 15 (depends on 13) The illumination optical apparatus according to claim 13, wherein a principal component of the first polarization state is linearly polarized light, circularly polarized light or elliptically polarized light. ### Claim 16 (depends on 13) The illumination optical apparatus according to claim 13, wherein the polarization state converter comprises at least one of a half wavelength plate and a quarter wavelength plate. ### Claim 17 (depends on 1) An exposure apparatus which exposes a substrate to light via an object having a pattern, the exposure apparatus comprising: a stage which holds the substrate, the illumination optical apparatus as defined in claim 1 which illuminates the pattern with the light; and a projection optical system which projects an image of the pattern illuminated with the light onto the substrate held by the stage. ### Claim 18 (depends on 17) The exposure apparatus according to claim 17, wherein the substrate is exposed to the light through liquid. ### Claim 19 (depends on 17) The exposure apparatus according to claim 17, wherein the illumination optical apparatus illuminates the object with the light in a polarization state in which a principal component is S-polarized light with respect to the object. ### Claim 20 (depends on 17) The exposure apparatus according to claim 17, wherein a first thickness of the polarization modulator in an optical path of a first part of the light is different from a second thickness of the polarization modulator in an optical path of a second part of the light, and the first part of the light passes through a first portion of the pupil plane away from the optical axis, and the second part of the light passes through a second portion of the illumination pupil plane away from the optical axis, the first and second portions being different from each other. ### Claim 21 (depends on 20) The exposure apparatus according to claim 20, further comprising a polarization state converter arranged in the optical path on an incidence side of the polarization modulator, wherein the polarization state converter converts a polarization state of the illumination light from a first polarization state including a substantially single polarization into a second polarization state different from the first polarization state. ### Claim 22 (depends on 21) The exposure apparatus according to claim 21, wherein a principal component of the second polarization state is linearly polarized light polarized substantially in the single direction. ### Claim 23 (depends on 21) The exposure apparatus according to claim 21, wherein a principal component of the first polarization state is linearly polarized light, circularly polarized light or elliptically polarized light. ### Claim 24 (depends on 21) The exposure apparatus according to claim 21, wherein the polarization state converter comprises at least one of a half wavelength plate and a quarter wavelength plate. ### Claim 25 (depends on 20) The exposure apparatus according to claim 20, wherein the first and second portions are included in an annular region about the optical axis. ### Claim 26 (depends on 25) The exposure apparatus according to claim 25, wherein the first and second portions are substantially discrete from each other. ### Claim 27 (depends on 20) The exposure apparatus according to claim 20, wherein the first and second portions are substantially discrete from each other and are aligned along a circumference about the optical axis. ### Claim 28 (depends on 17) A device manufacturing method, comprising: transferring a pattern to a substrate by using the exposure apparatus as defined in claim 17; and developing the substrate to which the pattern is transferred. ### Claim 29 (depends on 28) The device manufacturing method according to claim 28, wherein the pattern is transferred to the substrate with light through liquid. ### Claim 30 (depends on 1) An exposure method which exposes a substrate to light via an object having a pattern, the exposure method comprising: holding the substrate by a stage; illuminating the pattern with the light by using the illumination optical apparatus as defined in claim 1; and projecting an image of the pattern illuminated with the light onto the substrate held by the stage. ### Claim 31 (depends on 30) The exposure method according to claim 30, wherein the substrate is exposed to the light through liquid. ### Claim 32 (depends on 30) A device manufacturing method, comprising: transferring a pattern to a substrate by using the exposure method as defined in claim 30; and developing the substrate to which the pattern is transferred. ### Claim 33 (depends on 32) The device manufacturing method according to claim 32, wherein the pattern is transferred to the substrate with light through liquid.