Inspection apparatus, lithographic apparatus, lithographic processing cell and inspection method
First Claim
Patent Images
1. An inspection apparatus configured to measure a property of a substrate, the apparatus comprising:
- an illumination system configured to provide a beam of radiation;
a radiation projector configured to project the beam of radiation onto the substrate;
a numerical aperture lens;
a substrate comprising a mark with a line of symmetry that is parallel to and in alignment with a plane of symmetry of an illumination profile of the beam of radiation projected by the radiation projector,wherein the illumination profile comprises two quadrants spaced apart from each other, the two quadrants being substantially illuminated; and
a detector configured to detect the radiation beam reflected from a surface of the substrate and separately detect a zeroth diffraction order and a higher diffraction order,wherein the illumination profile is such that at least one characteristic of the mark is reconstructed using the separately detected zeroth diffraction order and the higher diffraction order.
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Accused Products
Abstract
For angular resolved spectrometry a radiation beam is used having an illumination profile having four quadrants is used. The first and third quadrants are illuminated whereas the second and fourth quadrants aren'"'"'t illuminated. The resulting pupil plane is thus also divided into four quadrants with only the zeroth order diffraction pattern appearing in the first and third quadrants and only the first order diffraction pattern appearing in the second and third quadrants.
32 Citations
27 Claims
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1. An inspection apparatus configured to measure a property of a substrate, the apparatus comprising:
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an illumination system configured to provide a beam of radiation; a radiation projector configured to project the beam of radiation onto the substrate; a numerical aperture lens; a substrate comprising a mark with a line of symmetry that is parallel to and in alignment with a plane of symmetry of an illumination profile of the beam of radiation projected by the radiation projector, wherein the illumination profile comprises two quadrants spaced apart from each other, the two quadrants being substantially illuminated; and a detector configured to detect the radiation beam reflected from a surface of the substrate and separately detect a zeroth diffraction order and a higher diffraction order, wherein the illumination profile is such that at least one characteristic of the mark is reconstructed using the separately detected zeroth diffraction order and the higher diffraction order. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A lithographic apparatus comprising:
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an illumination optical system arranged to illuminate a pattern; a projection optical system arranged to project an image of the pattern on to a substrate; and an inspection apparatus configured to measure a property of a substrate, the apparatus comprising; an illumination system configured to provide a beam of radiation; a radiation projector configured to project the beam of radiation onto the substrate; a numerical aperture lens; a substrate comprising a mark with a line of symmetry that is in parallel and in alignment with a plane of symmetry of an illumination profile of the beam of radiation projected by the radiation projector, wherein the illumination profile comprises two quadrants positioned opposite to each other, the two quadrants being substantially illuminated; and a detector configured to detect the radiation beam reflected from a surface of the substrate and separately detect a zeroth diffraction order and a higher diffraction order, wherein the illumination profile is such that at least one characteristic of the mark is reconstructed using the separately detected zeroth diffraction order and the higher diffraction order.
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12. A lithographic cell comprising:
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a coater arranged to coat substrates with a radiation sensitive layer; a lithographic apparatus arranged to expose images onto the radiation sensitive layer of substrates coated by the coater; a developer arranged to develop images exposed by the lithographic apparatus; and an inspection apparatus configured to measure a property of a substrate, the apparatus comprising; an illumination system configured to provide a beam of radiation; a radiation projector configured to project the beam of radiation onto the substrate; a numerical aperture lens; a substrate comprising a mark with a line of symmetry that is in parallel and in alignment with a plane of symmetry of an illumination profile of the beam of radiation projected by the radiation projector, wherein the illumination profile comprises two quadrants spaced apart from each other, the two quadrants being substantially illuminated; and a detector configured to detect the radiation beam reflected from a surface of the substrate and separately detect a zeroth diffraction order and a higher diffraction order, wherein the illumination profile is such that at least one characteristic of the mark is reconstructed using the separately detected zeroth diffraction order and the higher diffraction order.
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13. A method of measuring a property of a substrate, the method comprising:
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projecting a beam of radiation onto a target exposed on the substrate; aligning a line of symmetry of a mark on the substrate in parallel with a plane of symmetry of an illumination profile of the projected beam of radiation; detecting the radiation reflected by the substrate; and determining the property from the reflecting radiation, wherein; the illumination profile comprises two quadrants spaced apart from each other, the two quadrants being substantially illuminated; and the illumination profile of the beam of radiation projected by a radiation projector is such that an intensity distribution of the beam of radiation is not symmetric about an imaginary line in a pupil plane and passing through an optical axis of the radiation projector.
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14. An inspection apparatus configured to measure a property of a substrate, the apparatus comprising:
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an illumination system configured to provide a beam of radiation; a radiation projector configured to project the radiation beam onto the substrate; a numerical aperture lens; a substrate comprising a mark with a line of symmetry that is in parallel and in alignment with a plane of symmetry of an illumination profile of the beam of radiation projected by the radiation projector, wherein the illumination profile comprises two quadrants spaced apart from each other, the two quadrants being substantially illuminated; and a detector configured to detect the radiation beam reflected from a surface of the substrate and to separately detect a zeroth and a first diffraction orders, wherein the illumination profile of the radiation beam projected by the radiation projector is such that an intensity distribution of the radiation beam is not symmetric about the an imaginary line in a pupil plane and passing through an optical axis of the radiation projector. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A lithographic apparatus comprising:
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an illumination optical system arranged to illuminate a pattern; a projection optical system arranged to project an image of the pattern on to a substrate; and an inspection apparatus comprising; a substrate comprising a mark with a line of symmetry that is in parallel and in alignment with a plane of symmetry of an illumination profile of a beam of radiation projected by a radiation projector, wherein the illumination profile comprises two quadrants positioned opposite to each other, the two quadrants being substantially illuminated; and a detector configured to detect the radiation beam reflected from a surface of the substrate and to separately detect a zeroth and a first diffraction orders, wherein the illumination profile of the reflected radiation beam is such that an intensity distribution thereof is not symmetric about an imaginary line in a pupil plane and passing through an optical axis of the projection optical system.
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25. A lithographic cell comprising:
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a coater arranged to coat substrates with a radiation sensitive layer; a lithographic apparatus arranged to expose images onto the radiation sensitive layer of substrates coated by the coater; a developer arranged to develop images exposed by the lithographic apparatus; and an inspection apparatus comprising; a substrate comprising a mark with a line of symmetry that is in parallel and in alignment with a plane of symmetry of an illumination profile of a beam of radiation projected by a radiation projector, wherein the illumination profile comprises two quadrants spaced apart from each other, the two quadrants being substantially illuminated; and a detector configured to detect the radiation beam reflected from a surface of the substrate and to separately detect a zeroth and a first diffraction orders, wherein the illumination profile of the reflected radiation beam is such that an intensity distribution thereof is not symmetric about an imaginary line in a pupil plane and passing through an optical axis of the projection optical system.
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26. A method of measuring a property of a substrate, the method comprising:
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projecting, with a projection optical system, a beam of radiation onto a target exposed onto the substrate; aligning a line of symmetry of a mark on the substrate in parallel with a plane of symmetry of an illumination profile of the projected beam of radiation, wherein the illumination profile comprises two quadrants spaced apart from each other, the two quadrants being substantially illuminated; detecting radiation reflected by the substrate and separately detecting a zeroth diffraction order and a higher diffraction order; and reconstructing at least one characteristic of the mark using the separately detected zeroth diffraction order and the higher diffraction order. - View Dependent Claims (27)
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Specification