WO2020140859A1 - 光刻投影物镜 - Google Patents

光刻投影物镜 Download PDF

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Publication number
WO2020140859A1
WO2020140859A1 PCT/CN2019/129760 CN2019129760W WO2020140859A1 WO 2020140859 A1 WO2020140859 A1 WO 2020140859A1 CN 2019129760 W CN2019129760 W CN 2019129760W WO 2020140859 A1 WO2020140859 A1 WO 2020140859A1
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WIPO (PCT)
Prior art keywords
lens
lens group
lenses
projection objective
lithographic projection
Prior art date
Application number
PCT/CN2019/129760
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English (en)
French (fr)
Inventor
郭银章
Original Assignee
上海微电子装备（集团）股份有限公司
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Application filed by 上海微电子装备（集团）股份有限公司 filed Critical 上海微电子装备（集团）股份有限公司
Priority to KR1020217023880A priority Critical patent/KR102659492B1/ko
Priority to JP2021538724A priority patent/JP7273162B2/ja
Priority to US17/419,967 priority patent/US11899181B2/en
Publication of WO2020140859A1 publication Critical patent/WO2020140859A1/zh

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • 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
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70216—Mask projection systems
    • G03F7/70241—Optical aspects of refractive lens systems, i.e. comprising only refractive elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/0045—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0087—Simple or compound lenses with index gradient
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces
    • G02B3/04—Simple or compound lenses with non-spherical faces with continuous faces that are rotationally symmetrical but deviate from a true sphere, e.g. so called "aspheric" lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B9/00—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
    • G02B9/60—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having five components only
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B9/00—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
    • G02B9/64—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having more than six components
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • 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
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • 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
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70216—Mask projection systems
    • G03F7/70308—Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B2003/0093—Simple or compound lenses characterised by the shape

Definitions

  • Embodiments of the present application relate to lithography technology, for example, to a lithography projection objective.
  • Optical lithography is a technique that uses light to project and reproduce a mask pattern.
  • the integrated circuit is made by a projection exposure device.
  • graphics with different mask patterns are imaged on a substrate, such as a silicon wafer or liquid crystal display (LCD) panel, which is set to manufacture integrated circuits, thin film magnetic heads, liquid crystal display panels, or microelectromechanical devices System (Micro-Electro-Mechanical System, MEMS) and other series of structures.
  • MEMS microelectromechanical devices System
  • High imaging performance requires that the lithographic projection objective can achieve a large numerical aperture (for example, greater than the numerical aperture of 0.5), and the imaging aberration is controlled within a reasonable range. In some application scenarios, high imaging performance also requires lithography The projection objective can be applied to longer wavelengths (for example, greater than or equal to 193 nm). In the related art, the lithographic projection objective needs to use more aspheric lenses under high imaging performance requirements, and the processing cost is high.
  • Embodiments of the present application provide a lithographic projection objective lens to reduce the number of aspheric lenses and reduce processing costs.
  • An embodiment of the present application provides a lithographic projection objective lens including a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group arranged in sequence along an optical axis , Both the first lens group and the third lens group have negative power, the second lens group and the fourth lens group have positive power, and the power of the fifth lens group Is 0, the sum of the powers of the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group is 0; the lithography
  • the projection objective also includes a diaphragm;
  • the first lens group, the third lens group, and the fourth lens group all include aspheric lenses, and one aspheric lens includes an aspheric surface; the number of the aspheric lenses is greater than or equal to 4 and Less than or equal to 8.
  • all the aspheric lenses have an aspheric deviation of less than 0.5 mm; there is at least one aspheric deviation in the fourth lens group that is greater than Or an aspheric lens equal to 0.5mm; or,
  • the aspheric deviation of all the aspheric lenses is equal to 0.5mm; there is at least one aspheric deviation in the third lens group greater than or equal to 0.5mm Aspheric lens;
  • the aspherical surface deviation of the aspherical lens is the axial distance between the aspherical surface of the aspherical lens and the best-fit spherical surface.
  • the second lens group includes a plurality of lenses with positive power; the power value of the lenses with positive power in the first lens group is less than any lens in the second lens group The power value of.
  • both the first lens group and the third lens group include a meniscus lens.
  • the first lens group and the fourth lens group include at least two of the meniscus lenses.
  • the third lens group includes at least two aspheric lenses.
  • the diaphragm is located between two adjacent lenses in the fourth lens group.
  • the first lens group includes 3 lenses, and 2 of the 3 lenses in the first lens group are aspheric lenses;
  • the second lens group includes 4 lenses
  • the third lens group includes 3 lenses, and 2 of the 3 lenses in the third lens group are aspheric lenses;
  • the fourth lens group includes 7 lenses, and among the 7 lenses of the fourth lens group, there are 3 or 4 aspheric lenses;
  • the fifth lens group includes 2 lenses.
  • the light entrance surface and the light exit surface of any lens in the fifth lens group are flat.
  • the first lens group includes an anamorphic lens compensator, the anamorphic lens compensator is a lens in the first lens group, and the diameter-thickness ratio of the anamorphic lens compensator ranges from 9-10 ,
  • the diameter-thickness ratio is the ratio of the maximum aperture of the lens to the thickness;
  • the effective aperture of the first surface of the deformed lens compensator is ⁇ 1
  • the effective aperture of the second surface of the deformed lens compensator is ⁇ 2
  • the second surface of the deformed lens compensator is located at Between the first surface of the anamorphic lens compensator and the second lens group, ⁇ 2 - ⁇ 1 >20 mm.
  • the lithographic projection objective lens is suitable for light emitted by an Argon Fluoride (ArF) excimer laser and Krypton Fluoride (KrF) excimer laser.
  • ArF Argon Fluoride
  • KrF Krypton Fluoride
  • the maximum image-side numerical aperture of the lithographic projection objective is 0.82.
  • the conjugate distance of the object image of the lithographic projection objective lens is less than or equal to 1100 mm.
  • FIG. 1 is a schematic structural diagram of a lithographic projection objective provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of an optical path of a parallel flat plate provided by an embodiment of this application.
  • FIG. 3 is a distribution diagram of wave aberration in the field of view of the lithographic projection objective shown in FIG. 1;
  • FIG. 4 is a distribution diagram of the centroid distortion of the field of view of the lithographic projection objective shown in FIG. 1;
  • FIG. 5 is a schematic structural diagram of another lithographic projection objective provided by an embodiment of the present application.
  • FIG. 6 is a distribution diagram of wave aberration in the field of view of the lithographic projection objective shown in FIG. 5;
  • FIG. 7 is a distribution diagram of the center of field distortion of the lithographic projection objective shown in FIG. 5;
  • FIG. 8 is a schematic structural diagram of still another lithographic projection objective provided by an embodiment of the present application.
  • FIG. 9 is a distribution diagram of wave aberration in the field of view of the lithographic projection objective shown in FIG. 8;
  • FIG. 10 is a distribution diagram of the centroid distortion of the field of view of the lithographic projection objective shown in FIG. 8.
  • the lithographic projection objective includes a first lens group LG1, a second lens group LG2, and a third lens arranged in sequence along an optical axis Group LG3, fourth lens group LG4 and fifth lens group LG5, first lens group LG1 and third lens group LG3 all have negative power, second lens group LG2 and fourth lens group LG4 have positive power,
  • the power of the fifth lens group LG5 is 0, and the sum of the powers of the first lens group LG1, the second lens group LG2, the third lens group LG3, the fourth lens group LG4, and the fifth lens group LG5 is 0.
  • the first lens group LG1 is the front end of the lithographic projection objective (incident end, close to the object plane), the fifth lens group LG5 is the rear end of the lithographic projection objective (exit end, close to the image plane), and the waist is located in the third lens group Within LG3.
  • the first lens group LG1 and the third lens group LG3 have negative power, and the first lens group LG1 and the third lens group LG3 may mainly include negative lenses having negative power. These negative power negative lenses appear in the relatively small aperture of the optical path of the lithographic projection objective, so that the first lens group LG1 and the third lens group LG3 can use lenses with relatively small effective apertures, and Conducive to the correction of aberration midfield curvature.
  • the lithographic projection objective can be an optical system structure with a single waist.
  • the waist represents the position where the lens aperture shrinks, so the effective aperture of the spot passing through the corresponding lens decreases.
  • the aperture of the lens in the embodiments of the present application refers to the effective aperture of the lens.
  • the optical power is equal to the difference between the convergence of the image side beam and the convergence of the object side beam, which characterizes the ability of the optical system to deflect light.
  • the larger the absolute value of the power the stronger the ability to bend light, and the smaller the absolute value of the power, the weaker the ability to bend light.
  • the refracted light is convergent; when the power is negative, the refracted light is divergent.
  • the optical power can be applied to characterize a certain refractive surface of a lens (that is, a surface of the lens), can be applied to characterize a certain lens, or can be applicable to a system formed by multiple lenses (that is, a lens group).
  • the sum of the refractive powers of the first lens group LG1, the second lens group LG2, the third lens group LG3, the fourth lens group LG4, and the fifth lens group LG5 is 0, which is favorable for reducing the high numerical aperture It is difficult to correct the image quality of lithographic projection objectives.
  • the lithographic projection objective also includes an aperture (Aperture Stop, AS).
  • the effective aperture of the lithographic projection objective can be adjusted by adjusting the aperture AS, so the numerical aperture of the lithographic projection objective can be adjusted by adjusting the aperture AS to Adapt to different lithographic projection objective application scenarios.
  • the first lens group LG1, the third lens group LG3, and the fourth lens group LG4 each include an aspherical lens, and one aspherical lens includes an aspherical surface, and the other surface of the aspherical lens is spherical or planar. Because it is more difficult to process and detect aspheric lenses with only one aspheric surface than aspheric lenses with two aspheric surfaces, setting aspheric lenses includes an aspheric surface, which reduces the manufacturing and measurement of aspheric lenses cost.
  • the number of aspheric lenses is greater than or equal to 4 and less than or equal to 8. Among them, the aspheric lens is a lens having an aspheric surface.
  • aspheric surface should be understood as an aspheric surface with a maximum axial distance of 2 ⁇ m or more between the aspheric surface and the best-fit spherical surface. This definition is used to exclude spherical surfaces with desired deformations and aspheric surface parts that are usually introduced after lens/projection optical systems are manufactured to correct aberrations. These aberrations are usually caused by the manufacturing process rather than projection optics Inherent in the specific design of the system.
  • the lithographic projection objective provided by the embodiment of the present application includes five lens groups, and each lens group includes at least two lenses, and all control the light by means of refraction.
  • the aspheric lens in the embodiment of the present application has only one aspheric surface, which is beneficial to reduce the manufacturing and measurement costs of the aspheric lens.
  • the number of aspheric lenses is greater than or equal to 4 and less than or equal to 8, and fewer aspheric lenses are used, thereby reducing the number of aspheric lenses and reducing processing costs.
  • the maximum image-side numerical aperture of the lithographic projection objective provided by the embodiment of the present application can reach 0.82, which belongs to a lithographic projection objective with a high numerical aperture. Since the lithographic projection objective further includes the diaphragm AS, the numerical aperture of the lithographic projection objective can be realized by adjusting the diaphragm AS to 0-0.82.
  • the refractive index of the lens increases as the wavelength becomes shorter.
  • the refractive index of fused silica material in the 193nm band is 1.56, and the refractive index in the 248nm band is 1.508.
  • the lithographic projection objective provided by the embodiment of the present application may be designed based on the light (248 nm) emitted by the KrF excimer laser.
  • the lithographic projection objective provided by the embodiment of the present application may be suitable for the light emitted by the KrF excimer laser, that is, the light emitted by the KrF excimer laser is used as the exposure beam of the lithographic projection objective.
  • the lithographic projection objective can also be adapted to the light emitted by the ArF excimer laser, that is, the light emitted by the ArF excimer laser is used as the exposure beam of the lithographic projection objective.
  • all aspheric lenses have an aspheric deviation of less than or equal to 0.5 mm, and there is at least one aspheric deviation in the fourth lens group LG4 Aspheric lens greater than or equal to 0.5mm.
  • the aspherical surface deviation of the aspherical lens is the axial distance between the aspherical surface of the aspherical lens and the best-fit spherical surface.
  • the best-fit spherical surface is the spherical surface closest to the aspheric surface, and the deviation of the spherical surface and the aspheric surface in the optical axis direction is the smallest.
  • the best-fit sphere may be an envelope sphere that passes through the vertices and edges of the aspheric surface.
  • a highly aspherical lens a highly aspherical lens is a lens having an aspherical surface with a degree of deviation greater than or equal to 0.5 mm
  • the greater the degree of aspheric deviation the more difficult it is to manufacture and detect; the smaller the degree of aspheric deviation, the less difficult it is to manufacture and detect.
  • the difficulty of detection is mainly reflected in the design and manufacturing cost of computer-generated Hologram (CGH) used for correction in the detection of high-precision lens surface interferometer.
  • CGH computer-generated Hologram
  • the design and manufacturing cost of computational holograms used in the detection of surface aspherical interferometers with highly aspheric lenses is very high.
  • the embodiments of the present application not only ensure that the lithographic projection objective has good aberration correction capabilities, but also reduce the overall manufacturing cost of the aspheric lens in the lithographic projection objective.
  • the first lens group LG1 includes a first lens 1, a second lens 2, and a third lens 3 that are sequentially arranged along the optical axis.
  • the third lens group LG3 includes an eighth lens 8, a ninth lens 9, and a tenth transparent 10 that are sequentially arranged along the optical axis.
  • the eighth lens 8, the ninth lens 9 and the tenth transparent 10 are both negative lenses with negative refractive power.
  • the fourth lens group LG4 includes an eleventh lens 11, a twelfth lens 12, a thirteenth lens 13, a fourteenth lens 14, a fifteenth lens 15, a sixteenth lens 16 and a Seventeen lenses 17.
  • the sixteenth lens 16 in the fourth lens group LG4 is a highly aspherical lens.
  • the first lens 1 and the second lens 2 in the first lens group LG1, the ninth lens 9, the tenth lens 10, and the eleventh lens 11 in the third lens group LG3, and the tenth in the fourth lens group LG4 The aspheric deviation of the four lenses 14 is less than 0.5 mm.
  • the first lens group LG1 mainly includes a negative lens having negative power. If all negative lenses of negative refractive power are used in the first lens group LG1, it is not easy for the first lens group LG1 to eliminate aberrations. In the embodiment of the present application, at least one lens with positive refractive power is provided in the first lens group LG1 to better eliminate aberrations.
  • the first lens 1 and the third lens 3 are negative lenses with negative power
  • the second lens 2 is a positive lens with positive power.
  • the second lens group LG2 includes a plurality of lenses with positive power, and the power value of the lenses with positive power in the first lens group LG1 is less than any of the second lens group LG2 The power value of the lens.
  • the lens with positive power in the first lens group LG1 has a relatively small power value, and the lens with positive power in the first lens group LG1 does not affect the power of the first lens group LG1 and the lithographic projection objective It has a great influence and thus plays a fine-tuning role, which is beneficial to realize the sum of the powers of the first lens group LG1, the second lens group LG2, the third lens group LG3, the fourth lens group LG4 and the fifth lens group LG5 as 0.
  • the second lens group LG2 includes a fourth lens 4, a fifth lens 5, a sixth lens 6, and a seventh lens 7 that are sequentially arranged along the optical axis, the fourth lens 4, the fifth lens 5
  • the sixth lens 6 and the seventh lens 7 are all positive lenses with positive refractive power.
  • the power of the second lens 2 is smaller than the power of the fourth lens 5, the fifth lens 6, the sixth lens 6, and the seventh lens 7.
  • the fourth lens group LG4 mainly includes a positive lens having positive power. If all positive lenses of positive power are used in the fourth lens group LG4, it is not easy for the fourth lens group LG4 to eliminate aberrations. In the embodiment of the present application, at least one lens with negative refractive power is provided in the fourth lens group LG4 to better eliminate aberrations.
  • the eleventh lens 11, the twelfth lens 12, the thirteenth lens 13, the fifteenth lens 15, the sixteenth lens 16, and the seventeenth lens 17 are all of positive power Positive lens.
  • the fourteenth lens 14 is a negative lens having negative power.
  • the first lens group LG1 and the third lens group LG3 each include a meniscus lens.
  • the meniscus lens generally consists of two spherical surfaces with a small radius of curvature and little difference in value.
  • the meniscus lens exhibits a crescent shape and is set to correct aberrations. Compared with ordinary spherical lenses, meniscus lenses are difficult to process and costly to process.
  • the first lens group LG1 and the third lens group LG3 have negative refractive power.
  • the lenses in the first lens group LG1 and the third lens group LG3 appear in a relatively small area of the spot diameter in the optical path of the lithographic projection objective, so they will
  • the meniscus lens is provided in the first lens group LG1 and the third lens group LG3, which is beneficial to reduce the aperture of the meniscus lens, reduce the processing difficulty and processing cost of the meniscus lens, and thereby reduce the processing cost of the lithographic projection objective lens.
  • the first lens group LG1 and the fourth lens group LG4 include at least two meniscus lenses. Due to the high processing difficulty and processing cost of the meniscus lens, the number of meniscus lenses used in the lithographic projection objective provided in the embodiments of the present application is small, so the processing cost of the lithographic projection objective can be reduced.
  • the third lens 3 in the first lens group LG1 is a meniscus lens
  • the fourteenth lens 14 in the fourth lens group LG4 is a meniscus lens
  • the meniscus lens used in the embodiments of the present application may also satisfy that the concentricity of the meniscus lens is less than 100 mm, where the concentricity of the meniscus lens is the distance between the spherical center points of the two surfaces of the meniscus lens.
  • the meniscus lens has a very small optical power due to the spherical center corresponding to the front surface (the front surface is a spherical surface) and the spherical center corresponding to the rear surface (the rear surface is a spherical surface).
  • the edge field of view light can form an optical path difference, so that the meniscus lens can achieve corrections such as field curvature or advanced aberrations.
  • the center of the sphere corresponding to the front surface and the center of the sphere corresponding to the rear surface are very close, which is not conducive to optical centering, and the centering and edging of the lens is not good.
  • the concentricity of the meniscus lens provided by the embodiment of the present application is less than 100 mm, which can not only realize the correction of aberrations, but also ensure the processing performance of the meniscus lens.
  • the third lens group LG3 includes at least two aspheric lenses. Since the first lens group LG1 has positive power, the second lens group LG2 has positive power, the third lens group LG3 has negative power, and the fourth lens group LG4 has positive power, this arrangement makes the lithographic projection objective
  • the waist is located in the third lens group LG3, the lenses in the third lens group LG3 have a smaller aperture, so at least two aspheric lenses can be provided in the third lens group LG3, thereby reducing the aperture of the aspheric lens, The processing difficulty and the detection difficulty of the aspheric lens are reduced, thereby reducing the processing cost of the lithographic projection objective lens.
  • the eighth lens 8 and the tenth lens 10 are aspheric lenses.
  • the lithographic projection objective lens further includes an aperture AS, which is located between two adjacent lenses in the fourth lens group LG4.
  • the fourth lens group LG4 has a positive refractive power.
  • the fourth lens group LG4 includes a lens with the largest aperture in the entire lithographic projection objective.
  • the aperture of the lens refers to the effective aperture.
  • the diaphragm AS is located in the fourth lens group LG4, and the diaphragm AS is closer to the lens with the largest aperture, which is helpful for adjusting the numerical aperture of the lithographic projection objective.
  • the lens with the largest aperture in the lithographic projection objective is the thirteenth lens 13 in the fourth lens group LG4, the diaphragm AS is located in the fourth lens group LG4, and is located between the thirteenth lens 13 and the fourteenth lens
  • the diaphragm AS is set in the fourth lens group LG4
  • the diaphragm AS is located between the lens with the largest aperture in the lithographic projection objective and the lens adjacent to the lens with the largest aperture in the lithographic projection objective, the diaphragm
  • the distance between the AS and the lens with the largest aperture is the shortest (no other lens between the diaphragm AS and the thirteenth lens 13), which improves the convenience of adjusting the numerical aperture of the lithographic projection objective.
  • NA numerical aperture of the lithographic projection objective
  • FIG. 2 is a schematic diagram of an optical path of a parallel flat plate provided by an embodiment of the present application.
  • the light incident surface and the light exit surface of any lens in the fifth lens group LG5 are flat. That is to say, the lenses in the fifth lens group LG5 are all parallel flat plates, for example, flat glass can be used, and the power of any lens in the fifth lens group LG5 is 0.
  • the advantage of this design is that while ensuring the minimum aberration, the beam diameter of the last end of the lithographic projection objective is minimized, so that the size of the components of the lithographic projection objective near the rear end of the image plane is smaller and more compact.
  • the first light L1 and the second light L2 propagate according to the dotted line in FIG. 2 when the flat glass P is not placed, and cross at point A; the first light L1 and the second light L2 are placed on the flat glass
  • P is irradiated to one side surface of the flat glass P, and refracted at one side surface of the flat glass P, then continue to propagate in the flat glass P, then refracted at the other side surface of the flat glass P, and then continue Spread in the air and cross at point B. Due to the refraction effect of the parallel glass P, the distance D1 between the point A and the plate glass P, and the second distance D2 between the point B and the plate glass P, D 1 >D 2 .
  • the first light L1 and the second light L2 are regarded as the edges of a beam, it is easy to see that the presence of the flat glass P reduces the beam diameter.
  • the first lens group LG1 includes an anamorphic lens compensator
  • the anamorphic lens compensator is a lens in the first lens group LG1
  • the diameter-thickness ratio of the anamorphic lens compensator is 9-10, that is, the anamorphic lens
  • the diameter-to-thickness ratio of the compensator can be any value from 9:1 to 10:1, and includes end values 9:1 and 10:1.
  • the effective aperture of the first surface of the deformed lens compensator is ⁇ 1
  • the effective aperture of the second surface of the deformed lens compensator is ⁇ 2
  • the second surface of the deformed lens compensator is located at the first of the deformed lens compensator Between the surface and the second lens group LG2, ⁇ 2 - ⁇ 1 >20 mm.
  • the first surface of the deformed lens compensator may also be referred to as the front surface of the deformed lens compensator
  • the second surface of the deformed lens compensator may also be referred to as the rear surface of the deformed lens compensator.
  • the anamorphic lens compensator provided by the embodiment of the present application has a large difference in effective aperture between the first surface and the second surface, and the range of the diameter-thickness ratio is 9-10, which can compensate for other lenses in the lithographic projection objective.
  • the deformation that occurs during the process ensures the normal use of the lithographic projection objective.
  • the diameter-thickness ratio is the ratio of the maximum aperture of the lens to the thickness.
  • the aperture of the front surface of the lens is smaller than the aperture of the rear surface of the lens, then the ratio of the diameter to the thickness of the lens is the ratio of the aperture of the rear surface of the lens to the thickness.
  • the first lens 1 in the first lens group LG is an anamorphic lens compensator.
  • the first lens group LG1 includes three lenses, and the first lens group LG1 includes first lenses 1 and 2 arranged in sequence along the optical axis. Lens 2 and third lens 3.
  • the first lens 1 and the third lens 3 are negative lenses with negative power, and the second lens 2 is a positive lens with positive power.
  • the second lens group LG2 includes 4 lenses.
  • the second lens group LG2 includes a fourth lens 4, a fifth lens 6, a sixth lens 6, and a seventh lens 7 arranged in this order along the optical axis.
  • the lenses in the second lens group LG2 are all positive lenses with positive refractive power .
  • the third lens group LG3 includes three lenses, and the third lens group LG3 includes an eighth lens 8, a ninth lens 9, and a tenth transparent 10 that are sequentially arranged along the optical axis.
  • the lenses in the third lens group LG3 are all negative lenses with negative refractive power.
  • the three lenses of the third lens group LG3 there are two aspheric lenses, and the eighth lens 8 and the tenth transparent 10 are aspheric lenses.
  • the fourth lens group includes 7 lenses, and the fourth lens group LG4 includes eleventh lens 11, twelfth lens 12, thirteenth lens 13, fourteenth lens 14, and fifteenth lens arranged in sequence along the optical axis 15. Sixteenth lens 16 and seventeenth lens 17.
  • the fourteenth lens 14 is a negative lens having negative power, and the other lenses in the fourth lens group LG4 except the fourteenth lens 14 are positive lenses having positive power.
  • the eleventh lens 11, the fourteenth lens 14, and the sixteenth lens 16 are aspheric lenses.
  • the fifth lens group LG5 includes 2 lenses.
  • the fifth lens group LG5 includes an eighteenth lens 18 and a nineteenth lens 19 which are sequentially arranged along the optical axis.
  • the powers of the eighteenth lens 18 and the nineteenth lens 19 are all 0, and the eighteenth lens 18 and the The nineteenth lens 19 may be flat glass.
  • the numerical aperture of the lithographic projection objective provided by the embodiment of the present application can reach 0.82, the wavelength of the imaging beam can be 248.3271nm, the wavelength bandwidth is 0.35pm, the magnification is -1/4, the image side half field height is 54.6mm, and the lens
  • the maximum aperture is 274mm, the maximum aspheric lens aperture is 255mm, the number of aspheric lenses is 7, and the number of lenses is 19.
  • the average deviation of the aspheric surface is 0.21mm, the maximum deviation of the aspheric surface is 0.46mm, the telecentricity of the image side is 1.1 microradians, the average slope of the aspheric surface is 0.019, the maximum slope of the aspheric surface is 0.034, the maximum light angle is 50 degrees, and the wave image
  • the root mean square (Root Mean Square) (RMS) (in-field mean) is 0.0073 wavelengths, the distortion (in-field mean) is 1.5 nm, the diameter-thickness ratio of the deformed lens compensator is 9:1, and the lithographic projection objective is at a distance
  • the maximum at the image plane is 66mm (the example of this application takes 66mm from the image plane as an example for explanation.
  • other positions can be selected to compare the effective aperture of different lithographic projection objectives). 127.5mm.
  • the effective aperture of the lithographic projection objective at a distance of 66 mm from the image plane is usually about 170 mm.
  • the lithographic projection objective provided by the embodiment of the present application has a smaller bottom size, thus leaving more for the layout of other components Space.
  • the smaller bottom size can leave more space for the components such as the focusing and leveling device, so that the lithographic projection objective provided by the embodiments of the present application can be applied
  • a lithography machine including two workpiece tables is more effective than a lithography machine including only one workpiece table because the lithography of the workpieces on the two workpiece tables can be realized.
  • Work efficiency of the lithography machine is less than or equal to 1100 mm.
  • the object image conjugate distance is the distance between the object plane and the image plane projected by lithography.
  • the object image conjugate distance of the lithographic projection objective lens is usually around 1250 mm.
  • the lithography projection objective lens provided by the embodiment of the present application has a smaller object image conjugate distance, thereby shortening the length of the lithographic projection objective lens.
  • Table 1 A specific design value of the lithographic projection objective
  • Table 1 shows a specific design value of the lithographic projection objective.
  • the specific value can be adjusted according to product requirements, and is not a limitation of the embodiments of the present application.
  • the lithographic projection objective shown in Table 1 may be as shown in FIG. 1.
  • a lens generally includes two surfaces, each of which is a refractive surface.
  • the numbers in Table 1 are numbered according to the surfaces of multiple lenses. Among them, the serial number "1" indicates the object plane, the serial number "41" indicates the image plane, and the serial number "28” indicates the diaphragm.
  • a positive radius value indicates that the center of curvature is on the side of the surface close to the image plane, and a negative radius value indicates that the center of curvature is on the side of the surface close to the object plane.
  • the value in the "Thickness” column indicates the on-axis distance from the current surface to the next surface.
  • the refractive index is the refractive index at the center wavelength of 248.3271 nm.
  • the lens material may be fused silica material, denoted as'Silica', and the space in the column of "lens material” indicates air.
  • the space in the column of "refractive index” indicates the refractive index of air.
  • the refractive index of the fused silica material is the refractive index relative to air.
  • the aspherical surface may be represented by a Q-type (Q-type) aspherical polynomial.
  • the Q-type aspheric polynomial is:
  • z is the axial height of the surface in the Z direction
  • c bfs is the curvature of the best-fit spherical surface
  • x and y are the coordinate values in the X and Y directions, respectively, and the X, Y, and Z directions conform to the Cartesian coordinate system
  • k is the cone that best fits the cone
  • u is the normalized radial distance
  • a m is the polynomial coefficient
  • It is the m-th orthogonalized Jacobi polynomial with a m as the coefficient.
  • Table 2 A specific design value of the aspheric surface in the lithographic projection objective
  • Table 2 is a specific design value of the aspherical surface in the lithographic projection objective.
  • Surface 34 correspond to the serial numbers “2", “4", "17”, “20”, “22”, “29”, and “34” in Table 1.
  • the corresponding parameters in the Q-type aspheric polynomial not given in Table 2 are well known in the art.
  • the multiple parameters in the "Parameter” column of Table 2 are consistent with the Q-type aspheric polynomial.
  • FIG. 3 is a distribution diagram of wave aberration in the field of view of the lithographic projection objective shown in FIG. 1. Referring to FIGS. 1 and 3, the aberration has been eliminated and imaging in the field of view is good.
  • FIG. 4 is a distribution diagram of the centroid distortion of the field of view of the lithographic projection objective shown in FIG. 1.
  • the distortion is eliminated, and the imaging in the field of view is good.
  • the abscissa of FIGS. 3 and 4 is the height of the X-object field of view, which represents the height of the object-side field of view in the X direction
  • the unit of the abscissa is mm
  • the ordinate of FIGS. 3 and 4 is the Y-object side view
  • the field height indicates the height of the object field of view in the Y direction
  • the unit of the ordinate is mm.
  • FIG. 5 is a schematic structural diagram of another lithographic projection objective lens provided by an embodiment of the present application.
  • the second embodiment is the same as the first embodiment, and is not described here again.
  • the reference numerals in FIG. 5 are the same as those in FIG. The marks are the same, and the same points are not repeated here.
  • the first lens group LG1 includes three lenses, and the first lens group LG1 includes the first lens 1 and the second lens arranged in sequence along the optical axis. 2 ⁇ third ⁇ 3.
  • the first lens 1, the second lens 2, and the third lens 3 are all negative lenses with negative refractive power.
  • There are two aspheric lenses among the three lenses of the first lens group LG1, and the first lens 1 and the third lens 3 in the first lens group LG1 are aspheric lenses.
  • the second lens group LG2 includes 4 lenses.
  • the third lens group LG3 includes 3 lenses. There are 2 aspherical lenses among the 3 lenses of the third lens group LG3.
  • the fourth lens group includes 7 lenses, and the fourth lens group LG4 includes eleventh lens 11, twelfth lens 12, thirteenth lens 13, fourteenth lens 14, and fifteenth lens arranged in sequence along the optical axis 15. Sixteenth lens 16 and seventeenth lens 17.
  • the fifteenth lens 15 is a negative lens having negative refractive power, and the lenses in the fourth lens group LG4 other than the fifteenth lens 15 are positive lenses having positive refractive power. There are 4 aspheric lenses among the 7 lenses of the fourth lens group LG4.
  • the eleventh lens 11, the twelfth lens 12, the fifteenth lens 15 and the seventeenth lens 17 are aspheric lenses.
  • the fifth lens group LG5 includes 2 lenses.
  • the numerical aperture of the lithographic projection objective provided by the embodiment of the present application can reach 0.82, the wavelength of the imaging beam can be 248.3271nm, the wavelength bandwidth is 0.35pm, the magnification is -1/4, the image side half field height is 54.4mm, and the lens
  • the maximum aperture is 281mm, the maximum aspheric lens aperture is 237mm, the number of aspheric lenses is 8, and the number of lenses is 19.
  • the average deviation of the aspheric surface is 0.29mm, the maximum deviation of the aspheric surface is 0.44mm, the telecentricity of the image side is 0.9 microradians, the average slope of the aspheric surface is 0.03, the maximum slope of the aspheric surface is 0.045, the maximum light angle is 51.2 degrees, the wave image
  • the difference RMS (in-field mean) is 0.0045 wavelengths
  • the distortion (in-field mean) is 1.6 nm
  • the diameter-thickness ratio of the deformed lens compensator is 9:1
  • the maximum effective light transmission of the lithographic projection objective is 66 mm from the image plane
  • the caliber is 128.9mm.
  • Table 3 shows another specific design value of the lithographic projection objective.
  • the specific numerical value can be adjusted according to product requirements, and is not a limitation of the embodiments of the present application.
  • the lithographic projection objective shown in Table 3 may be as shown in FIG. 5.
  • a lens generally includes two surfaces, each of which is a refractive surface.
  • the numbers in Table 3 are numbered according to the surfaces of multiple lenses. Among them, the serial number "1" indicates the object plane, the serial number "41" indicates the image plane, and the serial number "27” indicates the diaphragm.
  • a positive radius value indicates that the center of curvature is on the side of the surface close to the image plane, and a negative radius value indicates that the center of curvature is on the side of the surface close to the object plane.
  • the value in the "Thickness” column indicates the on-axis distance from the current surface to the next surface.
  • the refractive index is the refractive index at the center wavelength of 248.3271 nm.
  • the lens material may be fused silica material, expressed as'FS_22_N2', and the space in the column of "lens material” indicates nitrogen gas.
  • "A_22_N2" in the column of "lens material” means air.
  • the space in the column of "refractive index” indicates the refractive index of nitrogen.
  • the refractive index of the fused silica material is the refractive index relative to nitrogen.
  • the second embodiment uses the Different from the first embodiment to indicate.
  • the aspherical surface may be represented by an ordinary aspherical polynomial, specifically:
  • z is the axial height of the surface in the Z direction
  • x and y are the coordinate values in the X and Y directions, respectively, and the X, Y, and Z directions conform to the Cartesian coordinate system
  • k is the cone that best fits the cone Coefficient
  • c is the curvature of the best fitting spherical surface.
  • A, B, C, D, E, F, G, H, J are all aspheric coefficients.
  • Table 4 is another specific design value of the aspheric surface in the lithographic projection objective, and "surface 2", “surface 5", “surface 16", “surface 19”, “surface 21", “surface 23” in Table 4 ", “Surface 31” and “Surface 35” and the serial numbers “2”, “5", “16”, “19”, “21”, “23”, “31” and “35” in Table 3 correspond.
  • FIG. 6 is a distribution diagram of wave aberration in the field of view of the lithographic projection objective shown in FIG. 5. Referring to FIGS. 5 and 6, the aberration has been eliminated and the imaging in the field of view is good.
  • FIG. 7 is a distribution diagram of the centroid distortion of the field of view of the lithographic projection objective shown in FIG. 5.
  • the distortion is eliminated and the imaging in the field of view is good.
  • the abscissa of FIGS. 6 and 7 is the height of the X object side field of view, which represents the height of the object side field of view in the X direction
  • the unit of the abscissa is mm
  • the ordinate of FIGS. 6 and 7 is the Y object side view
  • the field height indicates the height of the object field of view in the Y direction
  • the unit of the ordinate is mm.
  • FIG. 8 is a schematic structural diagram of yet another lithographic projection objective provided by an embodiment of the present application.
  • the third embodiment is the same as the first embodiment, and details are not described here.
  • the reference numerals in FIG. 8 are the same as those in FIG. The figure marks are consistent, and the similarities will not be repeated here.
  • the numerical aperture of the lithographic projection objective provided by the embodiment of the present application can reach 0.82, the wavelength of the imaging beam can be 248.3271nm, the wavelength bandwidth is 0.35pm, the magnification is -1/4, the image side half field height is 54.6mm, and the lens
  • the maximum aperture is 272mm, the maximum aspheric lens aperture is 227mm, the number of aspheric lenses is 4, and the number of lenses is 19.
  • the average deviation of the aspheric surface is 0.43mm
  • the maximum deviation of the aspheric surface is 0.59mm
  • the wave aberration RMS (in-field mean) is 0.0167 wavelengths
  • the distortion (in-field mean) is 0.3nm
  • the lithographic projection objective is at a distance from the image plane
  • the maximum effective light aperture at 66mm is 126.9mm.
  • Table 5 shows another specific design value of the lithographic projection objective lens.
  • the specific numerical value can be adjusted according to product requirements, which is not a limitation of the embodiments of the present application.
  • the lithographic projection objective shown in Table 5 may be as shown in FIG. 8.
  • a lens generally includes two surfaces, each of which is a refractive surface.
  • the numbers in Table 5 are numbered according to the surfaces of multiple lenses. Among them, the serial number "1" indicates the object plane, the serial number "40" indicates the image plane, and the serial number "28” indicates the diaphragm.
  • a positive radius value indicates that the center of curvature is on the side of the surface close to the image plane, and a negative radius value indicates that the center of curvature is on the side of the surface close to the object plane.
  • the value in the "Thickness” column indicates the on-axis distance from the current surface to the next surface.
  • the refractive index is the refractive index at the center wavelength of 248.3271 nm.
  • the lens material may be fused silica material, denoted as'Silica', and the space in the column of "lens material” indicates air.
  • the space in the column of "refractive index” indicates the refractive index of air.
  • the refractive index of the fused silica material is the refractive index relative to air.
  • the aspherical surface is represented by Q-type aspherical polynomial.
  • the aspherical polynomial representation and definition are the same as those in the first embodiment, which will not be repeated here.
  • Table 6 is another specific design value of the aspheric surface in the lithographic projection objective. "Surface 2", “Surface 5", “Surface 20” and “Surface 34" in Table 6 and the serial number “2" in Table 5 , "5", "20” and “34” correspond to each other.
  • the corresponding parameters in the Q-type aspheric polynomial not given in Table 6 are well known in the art.
  • the multiple parameters in the "Parameter” column of Table 6 are consistent with the Q-type aspheric polynomial.
  • FIG. 9 is a distribution diagram of wave aberration in the field of view of the lithographic projection objective shown in FIG. 8. Referring to FIGS. 8 and 9, the aberration has been eliminated and the imaging in the field of view is good.
  • FIG. 10 is a distribution diagram of the centroid distortion of the field of view of the lithographic projection objective shown in FIG. 8.
  • the distortion is eliminated, and the imaging in the field of view is good.
  • the abscissa of FIGS. 9 and 10 is the height of the X-object field of view, which indicates the height of the object field of view in the X direction
  • the unit of the abscissa is mm
  • the ordinate of FIGS. 3 and 4 is the Y object side view
  • the field height indicates the height of the object field of view in the Y direction
  • the unit of the ordinate is mm.

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Abstract

一种光刻投影物镜，包括沿光轴顺次排列的第一透镜组(LG1)、第二透镜组(LG2)、第三透镜组(LG3)、第四透镜组(LG4)和第五透镜组(LG5)，第一透镜组(LG1)和第三透镜组(LG3)均具有负光焦度，第二透镜组(LG2)和第四透镜组(LG4)均具有正光焦度，第五透镜组(LG5)的光焦度为0，第一透镜组(LG1)、第二透镜组(LG2)、第三透镜组(LG3)、第四透镜组(LG4)和第五透镜组(LG5)的光焦度的和为0；光刻投影物镜还包括光阑(AS)；第一透镜组(LG1)、第三透镜组(LG3)和第四透镜组(LG4)均包括非球面透镜，一个非球面透镜包括一个非球面表面；非球面透镜的数量大于或等于4且小于或等于8。

Description

光刻投影物镜
本申请要求在2018年12月30日提交中国专利局、申请号为201811648652.0的中国专利申请的优先权，该申请的全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及光刻技术，例如涉及一种光刻投影物镜。
背景技术
光学光刻是一种用光将掩模图案投影复制的技术。集成电路就是由投影曝光装置制成的。借助于投影曝光装置，具有不同掩模图案的图形被成像至基底上，如硅片或液晶显示器(Liquid Crystal Display，LCD)板，设置为制造集成电路、薄膜磁头、液晶显示板，或微机电系统(Micro-Electro-Mechanical System，MEMS)等一系列结构。过去数十年曝光设备技术水平不断发展，满足了更小线条尺寸，更大曝光面积，更高可靠性及产率，更低成本的需求。
高的成像性能要求光刻投影物镜能够实现较大的数值孔径(例如大于数值孔径0.5)，且成像的像差控制在合理的范围内，在一些应用场景中，高的成像性能还要求光刻投影物镜能够适用于较长波长(例如大于或等于193nm)，相关技术中的光刻投影物镜在高的成像性能要求下需要使用较多的非球面透镜，加工成本高。
发明内容
本申请实施例提供一种光刻投影物镜，以实现减少非球面透镜的数量，降低加工成本。
本申请实施例提供一种光刻投影物镜，所述光刻投影物镜包括沿光轴顺次排列的第一透镜组、第二透镜组、第三透镜组、第四透镜组和第五透镜组，所述第一透镜组和所述第三透镜组均具有负光焦度，所述第二透镜组和所述第四透镜组均具有正光焦度，所述第五透镜组的光焦度为0，所述第一透镜组、所述第二透镜组、所述第三透镜组、所述第四透镜组和所述第五透镜组的光焦度的 和为0；所述光刻投影物镜还包括光阑；
所述第一透镜组、所述第三透镜组和所述第四透镜组均包括非球面透镜，一个所述非球面透镜包括一个非球面表面；所述非球面透镜的数量大于或等于4且小于或等于8。
可选地，所述第一透镜组以及所述第三透镜组中，所有所述非球面透镜的非球面偏离度均小于0.5mm；所述第四透镜组中存在至少一个非球面偏离度大于或等于0.5mm的非球面透镜；或者，
所述第一透镜组以及所述第四透镜组中，所有所述非球面透镜的非球面偏离度均等于0.5mm；所述第三透镜组中存在至少一个非球面偏离度大于或等于0.5mm的非球面透镜；
其中，非球面透镜的非球面偏离度为非球面透镜的非球面表面与最佳拟合球面之间的轴向距离。
可选地，所述第四透镜组中存在至少一个具有负光焦度的透镜。
可选地，所述第一透镜组中存在至少一个具有正光焦度的透镜。
可选地，所述第二透镜组包括多个具有正光焦度的透镜；所述第一透镜组中具有正光焦度的透镜的光焦度数值，小于所述第二透镜组中任一透镜的光焦度数值。
可选地，所述第一透镜组和所述第三透镜组均包括弯月透镜。
可选地，所述第一透镜组和所述第四透镜组共包括至少两个所述弯月透镜。
可选地，所述第三透镜组包括至少两个非球面透镜。
可选地，所述光阑位于所述第四透镜组中相邻的两个透镜之间。
可选地，所述第一透镜组包括3个透镜，所述第一透镜组的3个透镜中有2个非球面透镜；
所述第二透镜组包括4个透镜；
所述第三透镜组包括3个透镜，所述第三透镜组的3个透镜中有2个非球面透镜；
所述第四透镜组包括7个透镜，所述第四透镜组的7个透镜中有3个或者4 个非球面透镜；
所述第五透镜组包括2个透镜。
可选地，所述第五透镜组中的任一透镜的入光面以及出光面均为平面。
可选地，所述第一透镜组包括变形镜片补偿器，所述变形镜片补偿器为所述第一透镜组中的一个透镜，所述变形镜片补偿器的径厚比的范围为9-10，径厚比为透镜的最大口径与厚度的比值；
所述变形镜片补偿器的第一表面的有效通光口径为φ 1，所述变形镜片补偿器的第二表面的有效通光口径为φ 2，所述变形镜片补偿器的第二表面位于所述变形镜片补偿器的第一表面与所述第二透镜组之间，φ 2-φ 1＞20mm。
可选地，所述光刻投影物镜适用于氟化氩(Argon Fluoride，ArF)准分子激光器发出的光，以及氟化氪(Krypton Fluoride，KrF)准分子激光器发出的光。
可选地，所述光刻投影物镜的最大像方数值孔径为0.82。
可选地，所述光刻投影物镜的物像共轭距小于或等于1100mm。
附图说明
图1为本申请实施例提供的一种光刻投影物镜的结构示意图；
图2为本申请实施例提供的平行平板的光路示意图；
图3为图1中所示光刻投影物镜的视场内波像差分布图；
图4为图1中所示光刻投影物镜的视场质心畸变分布图；
图5为本申请实施例提供的另一种光刻投影物镜的结构示意图；
图6为图5中所示光刻投影物镜的视场内波像差分布图；
图7为图5中所示光刻投影物镜的视场质心畸变分布图；
图8为本申请实施例提供的又一种光刻投影物镜的结构示意图；
图9为图8中所示光刻投影物镜的视场内波像差分布图；
图10为图8中所示光刻投影物镜的视场质心畸变分布图。
具体实施方式
下面结合附图和实施例对本申请作进一步的详细说明。可以理解的是，此处所描述的具体实施例仅仅用于解释本申请，而非对本申请的限定。为了便于描述，附图中仅示出了与本申请相关的部分而非全部结构。
实施例一
图1为本申请实施例提供的一种光刻投影物镜的结构示意图，参考图1，光刻投影物镜包括沿光轴顺次排列的第一透镜组LG1、第二透镜组LG2、第三透镜组LG3、第四透镜组LG4和第五透镜组LG5，第一透镜组LG1和第三透镜组LG3均具有负光焦度，第二透镜组LG2和第四透镜组LG4均具有正光焦度，第五透镜组LG5的光焦度为0，第一透镜组LG1、第二透镜组LG2、第三透镜组LG3、第四透镜组LG4和第五透镜组LG5的光焦度的和为0。第一透镜组LG1为光刻投影物镜的最前端(入射端，靠近物面)，第五透镜组LG5为光刻投影物镜的最后端(出射端，靠近像面)，腰部位于第三透镜组LG3内。第一透镜组LG1和第三透镜组LG3具有负光焦度，第一透镜组LG1和第三透镜组LG3可以主要包含具有负光焦度的负透镜。这些负光焦度的负透镜出现在光刻投影物镜光路中光斑口径相对较小的区域中，使得第一透镜组LG1和第三透镜组LG3能使用有效通光口径相对较小的透镜，而且有利于像差中场曲的矫正。光刻投影物镜可以为具有单个腰部的光学系统结构。腰部表示透镜口径收缩的位置，因此穿过相应透镜的光斑有效口径减小。本申请实施例中透镜的口径指的是透镜的有效通光口径。
其中，光焦度等于像方光束会聚度与物方光束会聚度之差，它表征光学系统偏折光线的能力。光焦度的绝对值越大，对光线的弯折能力越强，光焦度的绝对值越小，对光线的弯折能力越弱。光焦度为正数时，光线的屈折是汇聚性 的；光焦度为负数时，光线的屈折是发散性的。光焦度可以适用于表征一个透镜的某一个折射面(即透镜的一个表面)，可以适用于表征某一个透镜，也可以适用于表征多个透镜共同形成的系统(即透镜组)。第一透镜组LG1、第二透镜组LG2、第三透镜组LG3、第四透镜组LG4和第五透镜组LG5的光焦度的和越接近0，第一透镜组LG1、第二透镜组LG2、第三透镜组LG3、第四透镜组LG4和第五透镜组LG5构成的双远心结构的远心误差越小。本申请实施例中第一透镜组LG1、第二透镜组LG2、第三透镜组LG3、第四透镜组LG4和第五透镜组LG5的光焦度的和为0，有利于降低高数值孔径的光刻投影物镜的像质矫正难度。光刻投影物镜还包括光阑(Aperture Stop，AS)，可以通过调节光阑AS来调节光刻投影物镜有效通光口径，因此可以通过调节光阑AS来调节光刻投影物镜的数值孔径，以适应不同的光刻投影物镜应用场景。
第一透镜组LG1、第三透镜组LG3和第四透镜组LG4均包括非球面透镜，一个非球面透镜包括一个非球面表面，该非球面透镜的另一个表面为球面或者平面。因为只具有一个非球面表面的非球面透镜加工检测难度要远远低于具有两个非球面表面的非球面透镜，因此设置非球面透镜包括一个非球面表面，降低了非球面透镜的制造和测量成本。非球面透镜的数量大于或等于4且小于或等于8。其中，非球面透镜为具有非球面的透镜。这里所用的术语“非球面”应理解为非球面表面与最佳拟合球面之间的最大轴向距离2μm以上的非球面表面。该定义用于排除具有期望变形的球形表面以及通常在透镜/投影光学系统的制造之后为了对像差进行校正而引入的非球面表面部分，这些像差通常是由于制造过程引起的而不是投影光学系统的具体设计所固有的。
本申请实施例提供的光刻投影物镜包括五个透镜组，每个透镜组中包括至 少两个透镜，并全部采用折射的方式实现对光线的控制。本申请实施例中的非球面透镜只具有一个非球面表面，有利于降低非球面透镜的制造和测量成本。且本申请实施例中非球面透镜的数量大于或等于4小于或等于8，使用了较少的非球面透镜，从而实现减少非球面透镜的数量，降低加工成本。
可选地，本申请实施例提供的光刻投影物镜的最大像方数值孔径可以达到0.82，属于高数值孔径的光刻投影物镜。由于光刻投影物镜还包括光阑AS，因此可以通过调节光阑AS使光刻投影物镜的数值孔径实现0-0.82。
在紫外光刻领域，透镜的折射率随着波长变短而增加，例如：熔融石英材料在193nm波段下的折射率为1.56，在248nm波段下的折射率为1.508。在光刻投影物镜的数值孔径、视场和像差的要求固定时，长波长相对于短波长更难于实现。示例性地，本申请实施例提供的光刻投影物镜可以基于KrF准分子激光器发出的光(248nm)进行设计。因此本申请实施例提供的光刻投影物镜可以适用于KrF准分子激光器发出的光，即，使用KrF准分子激光器发出的光来作为光刻投影物镜的曝光光束。在其他实施方式中，光刻投影物镜还可以适用于ArF准分子激光器发出的光，即，使用ArF准分子激光器发出的光来作为光刻投影物镜的曝光光束。
可选地，参考图1，第一透镜组LG1以及第三透镜组LG3中，所有非球面透镜的非球面偏离度均小于或等于0.5mm，第四透镜组LG4中存在至少一个非球面偏离度大于或等于0.5mm的非球面透镜。其中，非球面透镜的非球面偏离度为非球面透镜的非球面表面与最佳拟合球面之间的轴向距离。在一实施例中，最佳拟合球面为最接近非球面的球面，此球面与非球面在光轴方向偏差最小。在一实施例中，最佳拟合球面可以为过非球面顶点和边缘的包络球。一方面， 高度非球面透镜(高度非球面透镜为具有非球面偏离度大于或等于0.5mm非球面表面的透镜)具有较好的像差矫正能力。另一方面，非球面偏离度越大的非球面，其制造以及检测难度越大；非球面偏离度越小的非球面，其制造以及检测难度越小。其中，检测难度主要体现在高精度的透镜表面面型干涉仪检测上所用于校正的计算全息(Computer-Generated Hologram，CGH)的设计和制造成本。高度非球面透镜的表面面型干涉仪检测上所用的计算全息的设计和制造成本非常高昂。在其他可选的实施方式中也可以为：第一透镜组LG1以及第三透镜组LG3中，所有非球面透镜的非球面偏离度均小于0.5mm，第四透镜组LG4中存在至少一个非球面偏离度大于或等于0.5mm的非球面透镜。本申请实施例既保证了光刻投影物镜具有良好的像差矫正能力，又降低了光刻投影物镜中非球面透镜总体的制作成本。
示例性地，参考图1，第一透镜组LG1包括沿光轴顺次排列的第一透镜1、第二透镜2和第三透镜3。第三透镜组LG3包括沿光轴顺次排列的第八透镜8、第九透镜9和第十透明10。第八透镜8第九透镜9和第十透明10均为具有负光焦度的负透镜。第四透镜组LG4包括沿光轴顺次排列的第十一透镜11、第十二透镜12、第十三透镜13、第十四透镜14、第十五透镜15、第十六透镜16和第十七透镜17。第四透镜组LG4中的第十六透镜16为高度非球面透镜。第一透镜组LG1中的第一透镜1和第二透镜2、第三透镜组LG3中的第九透镜9、第十透镜10和第十一透镜11，以及第四透镜组LG4中的第十四透镜14的非球面偏离度小于0.5mm。
可选地，参考图1，第一透镜组LG1中存在至少一个具有正光焦度的透镜。由于第一透镜组LG1具有负光焦度，第一透镜组LG1主要包含具有负光焦度的 负透镜。如果第一透镜组LG1中全部采用负光焦度的负透镜，则第一透镜组LG1不容易消除像差。本申请实施例中，通过在第一透镜组LG1中设置至少一个具有正光焦度的透镜，以更好地消除像差。
示例性地，参考图1，第一透镜1和第三透镜3为具有负光焦度的负透镜，第二透镜2为具有正光焦度的正透镜。
可选地，参考图1，第二透镜组LG2包括多个具有正光焦度的透镜，第一透镜组LG1中具有正光焦度的透镜的光焦度数值，小于第二透镜组LG2中任一透镜的光焦度数值。第一透镜组LG1中具有正光焦度的透镜的光焦度数值比较小，第一透镜组LG1中具有正光焦度的透镜不会对第一透镜组LG1以及光刻投影物镜的光焦度造成较大影响，从而起到微调的作用，有利于实现第一透镜组LG1、第二透镜组LG2、第三透镜组LG3、第四透镜组LG4和第五透镜组LG5的光焦度的和为0。
示例性地，参考图1，第二透镜组LG2包括沿光轴顺次排列的第四透镜4、第五透镜5、第六透镜6和第七透镜7，第四透镜4、第五透镜5、第六透镜6和第七透镜7均为具有正光焦度的正透镜。第二透镜2的光焦度小于第四透镜4、第五透镜5、第六透镜6和第七透镜7的光焦度。
可选地，参考图1，第四透镜组LG4中存在至少一个具有负光焦度的透镜。由于第四透镜组LG4具有正光焦度，第四透镜组LG4主要包含具有正光焦度的正透镜。如果第四透镜组LG4中全部采用正光焦度的正透镜，则第四透镜组LG4不容易消除像差。本申请实施例中，通过在第四透镜组LG4中设置至少一个具有负光焦度的透镜，以更好地消除像差。
示例性地，参考图1，第十一透镜11、第十二透镜12、第十三透镜13、第 十五透镜15、第十六透镜16和第十七透镜17均为具有正光焦度的正透镜。第十四透镜14为具有负光焦度的负透镜。
可选地，参考图1，第一透镜组LG1和第三透镜组LG3均包括弯月透镜。弯月透镜一般由两个曲率半径较小，数值相差也很少的球面构成，弯月透镜呈现出新月形，设置为矫正像差。弯月透镜相对于普通的球面透镜来说，其加工难度大、加工成本高。第一透镜组LG1和第三透镜组LG3具有负光焦度，第一透镜组LG1和第三透镜组LG3中的透镜出现在光刻投影物镜光路中光斑口径相对较小的区域中，因此将弯月透镜设置于第一透镜组LG1和第三透镜组LG3中，有利于减小弯月透镜的口径，降低弯月透镜的加工难度和加工成本，从而降低光刻投影物镜的加工成本。
可选地，参考图1，第一透镜组LG1和第四透镜组LG4共包括至少两个弯月透镜。由于弯月透镜的加工难度和加工成本较高，本申请实施例中提供的光刻投影物镜中使用的弯月透镜的数量较少，因此可以降低光刻投影物镜的加工成本。
示例性地，参考图1，第一透镜组LG1中的第三透镜3为弯月透镜，第四透镜组LG4中的第十四透镜14为弯月透镜。
本申请实施例中采用的弯月透镜还可以满足：弯月透镜的同心度小于100mm，其中，弯月透镜的同心度为弯月透镜的两个表面的球心点之间的距离。首先，弯月透镜由于前表面(前表面为球面)对应的球心和后表面(后表面为球面)对应的球心非常靠近，所以其光焦度非常小，弯月透镜的中心视场光线和边缘视场光线能形成光程差，从而弯月透镜可以实现例如场曲或高级像差等的校正。另外，在弯月透镜的加工过程中，由于前表面对应的球心和后表面对 应的球心非常靠近，不利于光学定心，透镜的定心磨边工艺性不好。本申请实施例提供的弯月透镜的同心度小于100mm，既可以实现对像差的校正，又能够保证弯月透镜的加工工艺性能。
可选地，参考图1，第三透镜组LG3包括至少两个非球面透镜。由于第一透镜组LG1具有正光焦度，第二透镜组LG2具有正光焦度，第三透镜组LG3具有负光焦度，第四透镜组LG4具有正光焦度，这种设置使得光刻投影物镜的腰部位于第三透镜组LG3内，第三透镜组LG3中的透镜具有较小的口径，因此可以在第三透镜组LG3内设置至少两个非球面透镜，从而减小非球面透镜的口径，降低非球面透镜的加工难度和检测难度，从而降低光刻投影物镜的加工成本。
示例性地，参考图1，第三透镜组LG3中，第八透镜8和第十透镜10为非球面透镜。
可选地，参考图1，光刻投影物镜还包括光阑AS，光阑AS位于第四透镜组LG4中相邻的两个透镜之间。第四透镜组LG4具有正光焦度，第四透镜组LG4中包括整个光刻投影物镜中口径最大的透镜，透镜的口径指的是有效通光口径。将光阑AS位于第四透镜组LG4中，光阑AS与口径最大的透镜距离较近，有利于调节光刻投影物镜的数值孔径。
示例性地，光刻投影物镜中口径最大的透镜为第四透镜组LG4中的第十三透镜13，光阑AS位于第四透镜组LG4中，且位于第十三透镜13与第十四透镜14之间，将光阑AS设置于第四透镜组LG4中，且光阑AS位于光刻投影物镜中口径最大的透镜和与光刻投影物镜中口径最大的透镜邻近的透镜之间，光阑AS与口径最大的透镜距离最近(光阑AS与第十三透镜13之间无其他透镜)， 提高了调节光刻投影物镜的数值孔径的便捷性。可以理解的是，可以通过光阑AS来调节光刻投影物镜的数值孔径，本申请实施例中光刻投影物镜的数值孔径(Numerical Aperture，NA)满足：0.5≤NA≤0.82。
图2为本申请实施例提供的平行平板的光路示意图，参考图1和图2，第五透镜组LG5中的任一透镜的入光面以及出光面均为平面。也就是说，第五透镜组LG5中的透镜均为平行平板，例如可以采用平板玻璃，第五透镜组LG5中任一透镜的光焦度为0。这样设计的优点在于，在保证像差最小的同时，最大限度地减小光刻投影物镜最后端的光束口径，从而使光刻投影物镜靠近像面的最后端的元器件的尺寸更小、更紧凑。
示例性地，参考图2，第一光线L1以及第二光线L2在未放置平板玻璃P时按照图2中虚线传播，并于点A交叉；第一光线L1以及第二光线L2在放置平板玻璃P时照射到平板玻璃P的一侧表面，并在平板玻璃P的一侧表面处发生折射，然后在平板玻璃P中继续传播，然后在平板玻璃P的另一侧表面处发生折射，然后继续在空气中传播，并于点B交叉。由于平行玻璃P的折射作用，点A与平板玻璃P之间的距离D1，点B与平板玻璃P之间的第二距离D2，D 1＞D 2。将第一光线L1与第二光线L2看做是一光束的边缘时，容易看出：平板玻璃P的存在减小了光束口径。
可选地，参考图1，第一透镜组LG1包括变形镜片补偿器，变形镜片补偿器为第一透镜组LG1中的一个透镜，变形镜片补偿器的径厚比为9-10，即变形镜片补偿器的径厚比可以为9：1到10：1中的任一数值，且包括端点值9：1和10：1。变形镜片补偿器的第一表面的有效通光口径为φ 1，变形镜片补偿器的第二表面的有效通光口径为φ 2，变形镜片补偿器的第二表面位于变形镜片补 偿器的第一表面与第二透镜组LG2之间，φ 2-φ 1＞20mm。变形镜片补偿器的第一表面也可以称为变形镜片补偿器的前表面，变形镜片补偿器的第二表面也可以称为变形镜片补偿器的后表面。本申请实施例提供的变形镜片补偿器，其第一表面和第二表面的有效通光口径差异较大，且径厚比的范围为9-10，可以补偿光刻投影物镜中其他透镜在使用过程中发生的形变，从而保证光刻投影物镜的正常使用。其中，径厚比为透镜的最大口径与厚度的比值。示例性地，透镜的前表面的口径小于该透镜的后表面的口径，则该透镜的径厚比为该透镜的后表面的口径与厚度的比值。
示例性地，参考图1，第一透镜组LG中的第一透镜1为变形镜片补偿器。
示例性地，参考图1，本申请实施例提供一种光刻投影物镜，第一透镜组LG1包括3个透镜，第一透镜组LG1包括沿光轴顺次排列的第一透镜1、第二透镜2和第三透镜3。第一透镜1和第三透镜3为具有负光焦度的负透镜，第二透镜2为具有正光焦度的正透镜。第一透镜组LG1的3个透镜中有2个非球面透镜，第一透镜组LG1中的第一透镜1与第二透镜2为非球面透镜。第二透镜组LG2包括4个透镜。第二透镜组LG2包括沿光轴顺次排列的第四透镜4、第五透镜5、第六透镜6和第七透镜7，第二透镜组LG2中的透镜全部为具有正光焦度的正透镜。第二透镜组LG2中无非球面透镜。第三透镜组LG3包括3个透镜，第三透镜组LG3包括沿光轴顺次排列的第八透镜8、第九透镜9和第十透明10。第三透镜组LG3中的透镜全部为具有负光焦度的负透镜。第三透镜组LG3的3个透镜中有2个非球面透镜，第八透镜8和第十透明10为非球面透镜。第四透镜组包括7个透镜，第四透镜组LG4包括沿光轴顺次排列的第十一透镜11、第十二透镜12、第十三透镜13、第十四透镜14、第十五透镜15、第十六 透镜16和第十七透镜17。第十四透镜14为具有负光焦度的负透镜，第四透镜组LG4中除第十四透镜14外的其他透镜为具有正光焦度的正透镜。第四透镜组LG4的7个透镜中有3个非球面透镜。第十一透镜11、第十四透镜14和第十六透镜16为非球面透镜。第五透镜组LG5包括2个透镜。第五透镜组LG5包括沿光轴顺次排列的第十八透镜18和第十九透镜19，第十八透镜18和第十九透镜19的光焦度均为0，第十八透镜18和第十九透镜19可以为平板玻璃。本申请实施例提供的光刻投影物镜的数值孔径可以达到0.82，成像光束的波长可以为248.3271nm，波长带宽为0.35pm，倍率为-1/4，像方半视场高度为54.6mm，透镜最大口径为274mm，最大非球面透镜口径为255mm，非球面透镜数量为7个，透镜数量为19个。非球面平均偏离度为0.21mm，非球面最大偏离度为0.46mm，像方远心为1.1微弧度，非球面平均斜率为0.019，非球面最大斜率为0.034，最大光线角度为50度，波像差均方根(Root Mean Square，RMS)(场内均值)为0.0073个波长，畸变(场内均值)为1.5nm，变形镜片补偿器的径厚比为9：1，光刻投影物镜在距离像面66mm处最大(本申请实施例以距离像面66mm为例进行解释说明，在其他实施方式中，还可以选择其他位置来比较不同光刻投影物镜的有效通光口径)的有效通光口径为127.5mm。相关技术中，光刻投影物镜距离像面66mm处的有效通光口径通常在170mm左右，本申请实施例提供的光刻投影物镜具有更小的底部尺寸，从而为其他部件的布局留出更多的空间。在本申请实施例提供的光刻投影物镜的实际使用场景中，较小的底部尺寸能为调焦调平装置等部件留出更多空间，从而本申请实施例提供的光刻投影物镜能应用于包括两个工件台的光刻机中，包括两个工件台的光刻机相对于仅包括一个工件台的光刻机而言，由于可以对两个工件台上的工件实现光刻，提高了光 刻机的工作效率。可选地，光刻投影物镜的物像共轭距小于或等于1100mm。物像共轭距为光刻投影的物平面与像平面之间的距离。相关技术中，光刻投影物镜的物像共轭距通常在1250mm左右，本申请实施例提供的光刻投影物镜具有更小的物像共轭距，从而可以缩短光刻投影物镜的长度。
表1光刻投影物镜的一种具体设计值
Figure PCTCN2019129760-appb-000001
Figure PCTCN2019129760-appb-000002
表1示出了光刻投影物镜的一种具体设计值，其具体数值大小可根据产品需求进行调节，并非对本申请实施例的限制。表1中示出的光刻投影物镜可以为图1中所示。一个透镜一般包括两个表面，每一个表面为一个折射面。表1中的序号根据多个透镜的表面来进行编号。其中，序号“1”表示物面，序号“41”表示像面，序号“28”表示光阑。正的半径值表示曲率中心在表面靠近像面一侧，负的半径值代表曲率中心在表面靠近物面一侧。“厚度”一栏中的数值表示当前表面到下一个表面的轴上距离。折射率是在中心波长为248.3271nm时的折射率。透镜材料可以为熔融二氧化硅材料，表示为’Silica’，“透镜材料”一栏中的空格表示空气。“折射率”一栏中的空格表示空气的折射率。熔融二氧化硅材料的折射率为相对于空气的折射率。
本申请示例性实施方式中，非球面可以用Q类(Q-type)非球面多项式表示。Q-type非球面多项式为：
Figure PCTCN2019129760-appb-000003
其中，z为表面Z向的轴向矢高，c bfs为最佳拟合球面的曲率，
Figure PCTCN2019129760-appb-000004
x和y的对角线上的径向距离，x和y分别为X向和Y向的坐标值，X向、Y向和Z向符合笛卡尔坐标系，k为最佳拟合圆锥的圆锥系数，u为归一化径向距离，a m为多项式系数，
Figure PCTCN2019129760-appb-000005
为以a m为系数的m阶正交化雅克比(jacobi)多项式。
表2光刻投影物镜中非球面的一种具体设计值
Figure PCTCN2019129760-appb-000006
表2为光刻投影物镜中非球面的一种具体设计值，表2中的“表面2”、“表面4”、“表面17”、“表面20”、“表面22”、“表面29”和“表面34”与表1中的序号“2”、“4”、“17”、“20”、“22”、“29”和“34”一一对应。表2中未给出的Q-type非球面多项式中对应的参数为本领域公知。表2“参数”一栏中的多个参数与Q-type非球面多项式相一致。
图3为图1中所示光刻投影物镜的视场内波像差分布图，参考图1和图3，像差已消除，视场内成像良好。
图4为图1中所示光刻投影物镜的视场质心畸变分布图，参考图1和图4， 畸变已消除，视场内成像良好。其中，图3和图4的横坐标为X物方视场高度，表示的是物方视场在X方向高度，横坐标的单位是mm，图3和图4的纵坐标为Y物方视场高度，表示的是物方视场在Y方向高度，纵坐标的单位是mm。
实施例二
图5为本申请实施例提供的另一种光刻投影物镜的结构示意图，实施例二中与实施例一相同之处在此不再赘述，图5中的附图标记与图1中的附图标记相一致，相同之处在此也不再赘述，参考图5，第一透镜组LG1包括3个透镜，第一透镜组LG1包括沿光轴顺次排列的第一透镜1、第二透镜2和第三透镜3。第一透镜1、第二透镜2和第三透镜3均为具有负光焦度的负透镜。第一透镜组LG1的3个透镜中有2个非球面透镜，第一透镜组LG1中的第一透镜1与第三透镜3为非球面透镜。第二透镜组LG2包括4个透镜。第三透镜组LG3包括3个透镜。第三透镜组LG3的3个透镜中有2个非球面透镜。第四透镜组包括7个透镜，第四透镜组LG4包括沿光轴顺次排列的第十一透镜11、第十二透镜12、第十三透镜13、第十四透镜14、第十五透镜15、第十六透镜16和第十七透镜17。第十五透镜15为具有负光焦度的负透镜，第四透镜组LG4中除第十五透镜15外的其他透镜为具有正光焦度的正透镜。第四透镜组LG4的7个透镜中有4个非球面透镜。第十一透镜11、第十二透镜12、第十五透镜15和第十七透镜17为非球面透镜。第五透镜组LG5包括2个透镜。本申请实施例提供的光刻投影物镜的数值孔径可以达到0.82，成像光束的波长可以为248.3271nm，波长带宽为0.35pm，倍率为-1/4，像方半视场高度为54.4mm，透镜最大口径为281mm，最大非球面透镜口径为237mm，非球面透镜数量为8个，透镜数量为19个。非球面平均偏离度为0.29mm，非球面最大偏离度为0.44mm，像方远心为0.9微弧 度，非球面平均斜率为0.03，非球面最大斜率为0.045，最大光线角度为51.2度，波像差RMS(场内均值)为0.0045个波长，畸变(场内均值)为1.6nm，变形镜片补偿器的径厚比为9：1，光刻投影物镜在距离像面66mm处最大的有效通光口径为128.9mm。
表3光刻投影物镜的另一种具体设计值
Figure PCTCN2019129760-appb-000007
Figure PCTCN2019129760-appb-000008
表3示出了光刻投影物镜的另一种具体设计值，其具体数值大小可根据产品需求进行调节，并非对本申请实施例的限制。表3中示出的光刻投影物镜可以为图5中所示。一个透镜一般包括两个表面，每一个表面为一个折射面。表3中的序号根据多个透镜的表面来进行编号。其中，序号“1”表示物面，序号“41”表示像面，序号“27”表示光阑。正的半径值表示曲率中心在表面靠近像面一侧，负的半径值代表曲率中心在表面靠近物面一侧。“厚度”一栏中的数值表示当前表面到下一个表面的轴上距离。折射率是在中心波长为248.3271nm时的折射率。透镜材料可以为熔融二氧化硅材料，表示为'FS_22_N2'，“透镜材料”一栏中的空格表示氮气。“透镜材料”一栏中的'A_22_N2'表示空气。“折射率”一栏中的空格表示氮气的折射率。熔融二氧化硅材料的折射率为相对于氮气的折射率。由于实施二中熔融二氧化硅材料的折射率为相对于氮气的折射率，而实施例一种熔融二氧化硅材料的折射率为相对于空气的折射率，为了区分，实施例二中使用了与实施例一不同的标记来表示。
本申请示例性实施方式中，非球面可以用普通非球面多项式表示，具体为：
Figure PCTCN2019129760-appb-000009
其中，z为表面Z向的轴向矢高，
Figure PCTCN2019129760-appb-000010
x和y的对角线上的径向距离，x和y分别为X向和Y向的坐标值，X向、Y向和Z向符合笛卡尔坐标系， k为最佳拟合圆锥的圆锥系数，c为最佳拟合球面的曲率。A,B,C,D,E,F,G,H,J均为非球面系数。
表4光刻投影物镜中非球面的另一种具体设计值
Figure PCTCN2019129760-appb-000011
表4为光刻投影物镜中非球面的另一种具体设计值，表4中的“表面2”、“表面5”、“表面16”、“表面19”、“表面21”、“表面23”、“表面31”和“表面35”与表3中的序号“2”、“5”、“16”、“19”、“21”、“23”、“31”和“35”一一对应。
图6为图5中所示光刻投影物镜的视场内波像差分布图，参考图5和图6，像差已消除，视场内成像良好。
图7为图5中所示光刻投影物镜的视场质心畸变分布图，参考图5和图7，畸变已消除，视场内成像良好。其中，图6和图7的横坐标为X物方视场高度，表示的是物方视场在X方向高度，横坐标的单位是mm，图6和图7的纵坐标为Y物方视场高度，表示的是物方视场在Y方向高度，纵坐标的单位是mm。
实施例三
图8为本申请实施例提供的又一种光刻投影物镜的结构示意图，实施例三中与实施例一相同之处在此不再赘述，图8中的附图标记与图1中的附图标记相一致，相同之处在此也不再赘述。
本申请实施例提供的光刻投影物镜的数值孔径可以达到0.82，成像光束的波长可以为248.3271nm，波长带宽为0.35pm，倍率为-1/4，像方半视场高度为54.6mm，透镜最大口径为272mm，最大非球面透镜口径为227mm，非球面透镜数量为4个，透镜数量为19个。非球面平均偏离度为0.43mm，非球面最大偏离度为0.59mm，波像差RMS(场内均值)为0.0167个波长，畸变(场内均值)为0.3nm，光刻投影物镜在距离像面66mm处最大的有效通光口径126.9mm。
表5光刻投影物镜的另一种具体设计值
Figure PCTCN2019129760-appb-000012
Figure PCTCN2019129760-appb-000013
表5示出了光刻投影物镜的另一种具体设计值，其具体数值大小可根据产品需求进行调节，并非对本申请实施例的限制。表5中示出的光刻投影物镜可以为图8中所示。一个透镜一般包括两个表面，每一个表面为一个折射面。表5中的序号根据多个透镜的表面来进行编号。其中，序号“1”表示物面，序号“40”表示像面，序号“28”表示光阑。正的半径值表示曲率中心在表面靠近像面一侧，负的半径值代表曲率中心在表面靠近物面一侧。“厚度”一栏中的数值表 示当前表面到下一个表面的轴上距离。折射率是在中心波长为248.3271nm时的折射率。透镜材料可以为熔融二氧化硅材料，表示为’Silica’，“透镜材料”一栏中的空格表示空气。“折射率”一栏中的空格表示空气的折射率。熔融二氧化硅材料的折射率为相对于空气的折射率。
实施例三中非球面用Q-type非球面多项式表示，非球面多项式表示和定义与实施例一相同之处在此不再赘述，详见实施例一中关于非球面Q-type非球面多项式表示和定义。
表6光刻投影物镜中非球面的另一种具体设计值
Figure PCTCN2019129760-appb-000014
表6为光刻投影物镜中非球面的另一种具体设计值，表6中的“表面2”、“表面5”、“表面20”和“表面34”与表5中的序号“2”、“5”、“20” 和“34”一一对应。表6中未给出的Q-type非球面多项式中对应的参数为本领域公知。表6“参数”一栏中的多个参数与Q-type非球面多项式相一致。
图9为图8中所示光刻投影物镜的视场内波像差分布图，参考图8和图9，像差已消除，视场内成像良好。
图10为图8中所示光刻投影物镜的视场质心畸变分布图，参考图8和图10，畸变已消除，视场内成像良好。其中，图9和图10的横坐标为X物方视场高度，表示的是物方视场在X方向高度，横坐标的单位是mm，图3和图4的纵坐标为Y物方视场高度，表示的是物方视场在Y方向高度，纵坐标的单位是mm。

Claims (15)

  1. 一种光刻投影物镜，包括沿光轴顺次排列的第一透镜组、第二透镜组、第三透镜组、第四透镜组和第五透镜组，所述第一透镜组和所述第三透镜组均具有负光焦度，所述第二透镜组和所述第四透镜组均具有正光焦度，所述第五透镜组的光焦度为0，所述第一透镜组、所述第二透镜组、所述第三透镜组、所述第四透镜组和所述第五透镜组的光焦度的和为0；所述光刻投影物镜还包括光阑；
    所述第一透镜组、所述第三透镜组和所述第四透镜组均包括非球面透镜，一个所述非球面透镜包括一个非球面表面；所述非球面透镜的数量大于或等于4且小于或等于8。
  2. 根据权利要求1所述的光刻投影物镜，其中，所述第一透镜组以及所述第三透镜组中，所有所述非球面透镜的非球面偏离度均小于0.5mm；所述第四透镜组中存在至少一个非球面偏离度大于或等于0.5mm的非球面透镜；或者，
    所述第一透镜组以及所述第四透镜组中，所有所述非球面透镜的非球面偏离度均小于0.5mm；所述第三透镜组中存在至少一个非球面偏离度大于或等于0.5mm的非球面透镜；
    其中，所述非球面透镜的非球面偏离度为所述非球面透镜的非球面表面与最佳拟合球面之间的轴向距离。
  3. 根据权利要求1所述的光刻投影物镜，其中，所述第四透镜组中存在至少一个具有负光焦度的透镜。
  4. 根据权利要求1所述的光刻投影物镜，其中，所述第一透镜组中存在至少一个具有正光焦度的透镜。
  5. 根据权利要求4所述的光刻投影物镜，其中，所述第二透镜组包括多个具有正光焦度的透镜；所述第一透镜组中具有正光焦度的透镜的光焦度数值，小于所述第二透镜组中任一透镜的光焦度数值。
  6. 根据权利要求1所述的光刻投影物镜，其中，所述第一透镜组和所述第三透镜组均包括弯月透镜。
  7. 根据权利要求6所述的光刻投影物镜，其中，所述第一透镜组和所述第四透镜组共包括至少两个所述弯月透镜。
  8. 根据权利要求1所述的光刻投影物镜，其中，所述第三透镜组包括至少两 个非球面透镜。
  9. 根据权利要求1所述的光刻投影物镜，其中，所述光阑位于所述第四透镜组中相邻的两个透镜之间。
  10. 根据权利要求1所述的光刻投影物镜，其中，所述第一透镜组包括3个透镜，所述第一透镜组的3个透镜中有2个非球面透镜；
    所述第二透镜组包括4个透镜；
    所述第三透镜组包括3个透镜，所述第三透镜组的3个透镜中有2个非球面透镜；
    所述第四透镜组包括7个透镜，所述第四透镜组的7个透镜中有3个或者4个非球面透镜；
    所述第五透镜组包括2个透镜。
  11. 根据权利要求1所述的光刻投影物镜，其中，所述第五透镜组中的任一透镜的入光面以及出光面均为平面。
  12. 根据权利要求1所述的光刻投影物镜，其中，所述第一透镜组包括变形镜片补偿器，所述变形镜片补偿器为所述第一透镜组中的一个透镜，所述变形镜片补偿器的径厚比的范围为9-10，所述径厚比为透镜的最大口径与厚度的比值；
    所述变形镜片补偿器的第一表面的有效通光口径为φ 1，所述变形镜片补偿器的第二表面的有效通光口径为φ 2，所述变形镜片补偿器的第二表面位于所述变形镜片补偿器的第一表面与所述第二透镜组之间，φ 2-φ 1＞20mm。
  13. 根据权利要求1所述的光刻投影物镜，其中，所述光刻投影物镜适用于氟化氩ArF准分子激光器发出的光，以及氟化氪KrF准分子激光器发出的光。
  14. 根据权利要求1所述的光刻投影物镜，其中，所述光刻投影物镜的最大像方数值孔径为0.82。
  15. 根据权利要求1所述的光刻投影物镜，其中，所述光刻投影物镜的物像共轭距小于或等于1100mm。
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