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AssigneeCarl Zeiss SMT GmbH
InventorsDaniel Krahmer, Toralf Gruner, Wilhelm Ulrich, Birgit Enkisch, Michael Gerhard, Martin Brunotte, Christian Wagner, Winfried Kaiser, Manfred Maul, Christoph Zaczek
Estimating the term…
An objective for a microlithography projection system has at least one fluoride crystal lens. The effects of birefringence, which are detrimental to the image quality, are reduced if the lens axis of the crystal lens is oriented substantially perpendicular to the {100}-planes or {100}-equivalent crystallographic planes of the fluoride crystal. If two or more fluoride crystal lenses are used, they should have lens axes oriented in the (100)-, (111)-, or (110)-direction of the crystallographic structure, and they should be oriented at rotated positions relative to each other. The birefringence-related effects are further reduced by using groups of mutually rotated (100)-lenses in combination with groups of mutually rotated (111)- or (110)-lenses. A further improvement is also achieved by applying a compensation coating to at least one optical element of the objective.
An objective comprising a plurality of lenses, wherein at least one lens consists of fluoride crystal with a cubic lattice structure and wherein said fluoride crystal lens is a (100)-lens with a lens axis oriented approximately perpendicular to the {100}-planes or to crystallographic planes that are equivalent to the {100}-planes of the fluoride crystal, wherein light rays travel inside the objective from an object plane to an image plane and at least one light ray among said light rays has a ray angle inside the (100)-lens of more than 25° relative to the lens axis.
An objective comprising a plurality of lenses, wherein at least one lens consists of fluoride crystal with a cubic lattice structure and wherein said fluoride crystal lens is a (100)-lens with a lens axis oriented approximately perpendicular to the {100}-planes or to crystallographic planes that are equivalent to the {100}-planes of the fluoride crystal, further comprising a diaphragm in a diaphragm plane, wherein the diaphragm has a diaphragm diameter and the (100)-lens has a lens diameter that is smaller than 85% of the diaphragm diameter.
An objective comprising a plurality of lenses, wherein at least one lens consists of fluoride crystal with a cubic lattice structure and wherein said fluoride crystal lens is a (100)-lens with a lens axis oriented approximately perpendicular to the {100}-planes or to crystallographic planes that are equivalent to the {100}-planes of the fluoride crystal, further comprising an image plane, wherein the (100)-lens is the lens nearest to the image plane among said plurality of lenses.
An objective comprising a plurality of lenses, wherein at least one lens consists of fluoride crystal and wherein said fluoride crystal lens is a (100)-lens with a lens axis oriented approximately perpendicular to the {100}-planes or to crystallographic planes that are equivalent to the {100}-planes of the fluoride crystal.
An objective comprising two lenses consisting of fluoride crystal material with a cubic lattice structure, wherein said lenses have lens axes oriented substantially in the crystallographic <111>-direction or a principal crystallographic direction equivalent to the <111>-direction, wherein said lenses are arranged with a 60° rotation relative to each other about the lens axes.
An objective comprising at least two lenses consisting of fluoride crystal material with a cubic lattice structure, wherein said lenses have lens axes oriented substantially in the crystallographic <111>-direction or a principal crystallographic direction equivalent to the <111>-direction, wherein said lenses are arranged with a rotation relative to each other about the lens axes to compensate for the effects of intrinsic birefringence of fluoride crystal material.
An objective comprising a plurality of lenses, wherein at least two lenses consist of fluoride crystal material with a cubic lattice structure and wherein said fluoride crystal lenses are (111)-lenses each having a lens axis oriented approximately perpendicular to the {111}-planes or to crystallographic planes that are equivalent to the {111}-planes of the fluoride crystal, wherein an image point in an image plane is formed at a convergence of a bundle of light rays each of which has an azimuth angle αR, an aperture angle θR and an optical path difference ΔOPL for two mutually orthogonal states of linear polarization, wherein said (111)-lenses are arranged with a rotation relative to each other about the lens axes in such a manner that a distribution ΔOPL(αR, θR) of the optical path differences as a function of the azimuth angle αR and the aperture angle θR has significantly reduced values of ΔOPL in comparison to an arrangement where said (111)-lenses are not arranged with said rotation relative to each other.
A method of manufacturing objectives that comprise at least two fluoride crystal lenses, wherein the term lenses means lenses as well as lens parts, wherein said fluoride crystal lenses are (111)-lenses each having a lens axis oriented approximately perpendicular to the {111}-planes or to crystallographic planes that are equivalent to the {111}-planes of the fluoride crystal, the method comprising the steps of:
An objective comprising two lenses consisting of fluoride crystal material with a cubic lattice structure, wherein said lenses have lens axes oriented substantially in the crystallographic <100>-direction or a principal crystallographic direction equivalent to the <100>-direction, wherein said lenses are arranged with a 45° rotation relative to each other about the lens axes.
An objective comprising at least two lenses consisting of fluoride crystal material with a cubic lattice structure, wherein said lenses have lens axes oriented substantially in the crystallographic <100>-direction or a principal crystallographic direction equivalent to the <100>-direction, wherein said lenses are arranged with a rotation relative to each other about the lens axes to compensate for the effects of intrinsic birefringence of fluoride crystal material.
An objective comprising a plurality of lenses, wherein at least two lenses consist of fluoride crystal material with a cubic lattice structure and wherein said fluoride crystal lenses are (100)-lenses each having a lens axis oriented approximately perpendicular to the {100}-planes or to crystallographic planes that are equivalent to the {100}-planes of the fluoride crystal, wherein an image point in an image plane is formed at a convergence of a bundle of light rays each of which has an azimuth angle αR, an aperture angle θR and an optical path difference ΔOPL for two mutually orthogonal states of linear polarization, wherein said (100)-lenses are arranged with a rotation relative to each other about the lens axes in such a manner that a distributionΔOPL(αR, θR) of the optical path differences as a function of the azimuth angle αR and the aperture angle θR has significantly reduced values of ΔOPL in comparison to an arrangement where said (100)-lenses are not arranged with said rotation relative to each other.
A method of manufacturing objectives that comprise at least two fluoride crystal lenses, wherein the term lenses means lenses as well as lens parts, wherein said fluoride crystal lenses are (100)-lenses each having a lens axis oriented approximately perpendicular to the {100}-planes or to crystallographic planes that are equivalent to the {100}-planes of the fluoride crystal, the method comprising the steps of:
An objective comprising two lenses consisting of fluoride crystal material with a cubic lattice structure, wherein said two lenses have lens axes oriented substantially in the crystallographic <111>-direction or a principal crystallographic direction equivalent to the <111>-direction, wherein said two lenses are arranged with an angle of rotation γ relative to each other about the lens axes, wherein the angle of rotation γ conforms to the equation γ=l·120°±10° with l representing an integer, and wherein a light bundle originating from an object point on the optical axis has a local diameter maximum between the two lenses.
An objective comprising two lenses consisting of fluoride crystal material with a cubic lattice structure, wherein said two lenses have lens axes oriented substantially in the crystallographic <111>-direction or a principal crystallographic direction equivalent to the <111>-direction, wherein said two lenses are arranged with an angle of rotation γ relative to each other about the lens axes, wherein the angle of rotation γ conforms to the equation γ=l·120°±10° with l representing an integer, and wherein a light bundle originating from an object point on the optical axis has a local diameter minimum between the two lenses.
An objective comprising a plurality of lenses, wherein at least two lenses of at least one first group consist of fluoride crystal material with a cubic lattice structure and wherein said fluoride crystal lenses are (111)-lenses each having a lens axis oriented approximately perpendicular to the {111}-planes or to crystallographic planes that are equivalent to the {111}-planes of the fluoride crystal,
A method of manufacturing objectives that comprises a plurality of lenses, wherein at least two lenses of at least one first group consist of fluoride crystal material with a cubic lattice structure and wherein said fluoride crystal lenses are (111)-lenses each having a lens axis oriented approximately perpendicular to the {111}-planes or to crystallographic planes that are equivalent to the {111}-planes of the fluoride crystal,
An objective comprising at least two lenses consisting of fluoride crystal material, wherein the term lenses means lenses as well as lens parts, wherein said lenses have lens axes oriented substantially in a principal crystallographic direction, wherein an image point in an image plane (O′) is formed at a convergence of a bundle of light rays each of which has an azimuth angle αR, an aperture angle θR and an optical path difference ΔOPL for two mutually orthogonal states of linear polarization, wherein the lenses are arranged with a rotation relative to each other about the lens axes in such a manner that a distribution ΔOPL(αR, θR) of the optical path differences as a function of the azimuth angle αR and the aperture angle θR has significantly reduced values of ΔOPL in comparison to an arrangement where said lenses are likewise oriented in said principal crystallographic direction but are not arranged with said rotation relative to each other.
A method of manufacturing objectives that comprise at least two fluoride crystal lenses, wherein the term lenses means lenses as well as lens parts, wherein said lenses have lens axes and each of said lens axes is oriented substantially in a principal crystallographic direction, the method comprising the steps of:
An objective comprising a plurality of optical elements with optical surfaces, said optical elements including lenses of a fluoride crystal material with a cubic lattice structure, wherein the term lenses means lenses as well as lens parts, wherein an image point in an image plane is formed at a convergence of a bundle of light rays each of which has an optical path difference ΔOPL for two mutually orthogonal states of linear polarization, and wherein at least one of the optical surfaces is coated with a compensation coating (613), said compensation coating being configured in such a way that the optical path differences ΔOPL that are caused by the fluoride crystal lenses are significantly reduced in magnitude in comparison to an objective without the compensation coating.
An objective comprising a plurality of optical elements with optical surfaces, said optical elements including fluoride crystal lenses, wherein the term lenses means lenses as well as lens parts, wherein an image point in an image plane (O′) is formed at a convergence of a bundle of light rays each of which has an optical path difference ΔOPL for two mutually orthogonal states of linear polarization, and wherein at least one of the optical surfaces is coated with a compensation coating, said compensation coating being configured in such a way that the optical path differences ΔOPL are significantly reduced in magnitude in comparison to an objective without the compensation coating.
A method of compensating effects caused by birefringence in an objective that has a plurality of optical elements with optical surfaces, including fluoride crystal lenses, wherein at least one of said optical elements is an interchangeable element, wherein an image point in an image plane is formed at a convergence of a bundle of light rays, each of said rays having an azimuth angle αR, an aperture angle θR and an optical path difference ΔOPL for two mutually orthogonal states of linear polarization, and wherein said method comprises the steps of
A method of manufacturing a lens by joining a plurality of plates consisting of crystal material with a cubic lattice structure, wherein each plate has optical surfaces and a normal axis, wherein said plurality of plates comprises two (111)-plates whose normal axis is oriented in the crystallographic <111>-direction or a <111>-equivalent direction, wherein said plates are arranged with an angle of rotation γ relative to each other about the normal axes, wherein the angle of rotation γ conforms to the equation γ=60°+m·120°±10° with m representing an integer, wherein the method comprises the steps of
A method of manufacturing a lens by joining a plurality of plates consisting of crystal material with a cubic lattice structure, wherein each plate has optical surfaces and a normal axis, wherein said plurality of plates comprises two (100)-plates whose normal axis is oriented in the crystallographic <100>-direction or a <100>-equivalent direction, wherein said plates are arranged with an angle of rotation γ relative to each other about the normal axes, wherein the angle of rotation γ conforms to the equation γ=45°+m·90°±10° with m representing an integer, wherein the method comprises the steps of
A method of manufacturing a lens by joining a plurality of plates consisting of crystal material with a cubic lattice structure, wherein each plate has optical surfaces and a normal axis, wherein said plurality of plates comprises two (100)-plates whose normal axis is oriented in the crystallographic <100>-direction or a <100>-equivalent direction and two (111)-plates whose normal axis is oriented in the crystallographic <111>-direction or a <111>-equivalent direction, wherein said plates are arranged with an angle of rotation γ relative to each other about the normal axes, wherein the angle of rotation γ between two (100)-plates conforms to the equation γ=45°+m·90°±10° with m representing an integer, wherein the angle of rotation γ between two (111)-plates conforms to the equation γ=60°+m·120°±10° with m representing an integer,
A method of manufacturing a lens by joining a plurality of plates consisting of crystal material, wherein each plate has optical surfaces and a normal axis, wherein the method comprises the steps of
A method of manufacturing an optical black from a block of crystal material of a cubic crystallographic structure as a preliminary stage in manufacturing a lens for an objective, wherein the term lens means a lens as well as a lens part, said method comprising the steps of
An optical blank which is made from a crystal material of a cubic crystallographic structure and which is used as an initial product stage in manufacturing a lens, wherein the term lens means a lens as well as a lens part, said optical blank comprising a mark that indicates a reference direction, said reference direction being perpendicular to a first crystallographic direction of the optical blank, and said reference direction further being coincident with a projection of a second crystallographic direction into a plane that is perpendicular to the first crystallographic direction, the first crystallographic direction running at a non-zero angle to the second crystallographic direction, wherein said mark is on one of the optical blank and a mounting element of the optical blank.
A method of making a lens from an optical blank of a crystal material with a cubic crystallographic structure, the term lens meaning a lens as well as a lens part and wherein said lens has a lens axis, wherein a first crystallographic direction has a defined orientation relative to the optical blank, said method comprising
A lens made of a crystal material for an objective, wherein the term lens means a lens as well as a lens part, said lens having a lens axis oriented in a first principal crystallographic direction and comprising a mark that indicates a reference direction which is perpendicular to the first principal crystallographic direction, wherein said reference direction is coincident with a projection of a second principal crystallographic direction into a plane that is perpendicular to the first crystallographic direction, and wherein the first crystallographic direction runs at a non-zero angle to the second crystallographic direction, wherein said mark is on one of the lens and a mounting element of the lens.
Dependencies are inferred from the claim text.