Deep ultraviolet microscope objective and microscope

Abstract

The utility model provides a kind of deep ultraviolet microscope objective and microscope. Wherein deep ultraviolet microscope objective includes: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens and ninth lens are sequentially arranged from object side to image side with optical axis. The utility model, through the specific parameters and structure of each lens are set, so that the magnification of deep ultraviolet microscope objective is-50x, object field diameter is 0.48mm, using 200mm focal length tube lens, image field diameter is 24mm, working distance is 13mm, corresponding numerical aperture NA is larger, for 0.55, realize the independent design of deep ultraviolet microscope objective, so that deep ultraviolet microscope objective can better match semiconductor measuring equipment;While improving imaging quality and image field, achromatism of 260nm to 262nm deep ultraviolet band is realized, and spherical aberration, coma, astigmatism, field curvature, distortion, axial chromatic aberration and vertical axis chromatic aberration are well corrected.

Description

Technical Field

[0001] This utility model relates to the field of microscopes, and in particular to a deep ultraviolet microscope objective and a microscope. Background Technology

[0002] With the rapid development of micro-nano fabrication technology, the feature size of integrated circuits is becoming increasingly smaller. To meet the ever-increasing integration requirements of semiconductor metrology equipment, it is essential to use microscope objectives designed specifically for these needs. Currently, domestic and foreign manufacturers cannot provide deep ultraviolet microscope objectives for specific wavelengths, especially the 261nm band, which is detrimental to the development of optical systems. Furthermore, domestic and foreign manufacturers do not provide high-order optical parameters for 50x microscope objectives, making it impossible to design microscope objectives specifically for semiconductor metrology equipment. This affects the system's integration level and may even reduce the imaging quality of the optical system. Utility Model Content

[0003] One objective of this invention is to achieve independent design of deep ultraviolet microscope objectives, so that deep ultraviolet microscope objectives can be better matched with semiconductor measurement equipment.

[0004] A further objective of this invention is to improve the imaging quality and image-side field of view of deep ultraviolet microscope objectives, achieve achromatic correction in the deep ultraviolet band, and correct spherical aberration, coma, astigmatism, field curvature, distortion, axial chromatic aberration, and transverse chromatic aberration.

[0005] Specifically, this invention provides a deep ultraviolet microscope objective, comprising: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged coaxially from the object side to the image side; the first lens has a concave surface facing the object side and a convex surface facing the image side; the second lens has a concave surface facing the object side and a convex surface facing the image side; the third lens has a concave surface facing the object side and a convex surface facing the image side; the fourth lens has a convex surface facing the object side and a convex surface facing the image side; the fifth lens has a convex surface facing the object side and a convex surface facing the image side; the sixth lens has a convex surface facing the object side and a concave surface facing the image side; the seventh lens has a convex surface facing the object side and a concave surface facing the image side; the eighth lens has a convex surface facing the object side and a concave surface facing the image side; and the ninth lens has a concave surface facing the object side and a concave surface facing the image side.

[0006] Optionally, 11.5 < fL1 / f < 14.5, 17 < fL2 / f < 20, 17.5 < fL3 / f < 20.5, 20 < fL4 / f < 23, 15.5 < fL5 / f < 18.5, 27.5 < fL6 / f < 30.5, -8.5 < fL7 / f < -5.5, 10.5 < fL8 / f < 13.5, -4.5 < fL9 / f < -1.5, where fL1 is the focal length of the first lens, fL2 is the focal length of the second lens, fL3 is the focal length of the third lens, fL4 is the focal length of the fourth lens, fL5 is the focal length of the fifth lens, fL6 is the focal length of the sixth lens, fL7 is the focal length of the seventh lens, fL8 is the focal length of the eighth lens, fL9 is the focal length of the ninth lens, and f is the focal length of the deep ultraviolet microscope objective.

[0007] Optionally, the first lens, the second lens, the third lens, the sixth lens, and the eighth lens are all positive meniscus lenses with positive optical power; the fourth lens and the fifth lens are both biconvex lenses with positive optical power; the seventh lens is a negative meniscus lens with negative optical power; and the ninth lens is a biconcave lens with negative optical power.

[0008] Optionally, the first lens, the third lens, the fifth lens, the sixth lens, the seventh lens, and the ninth lens all satisfy the following conditions: 1.45 < nd < 1.65, 60 < Vd < 85; the second lens, the fourth lens, and the eighth lens all satisfy the following conditions: 1.25 < nd < 1.45, 85 < Vd < 110, where nd is the refractive index at a wavelength of 587.6 nm, and Vd is the Abbe number at a wavelength of 587.6 nm.

[0009] Optionally, the first lens has a refractive index of 1.5 and an Abbe number of 70; the second lens has a refractive index of 1.4 and an Abbe number of 95; the third lens has a refractive index of 1.55 and an Abbe number of 70; the fourth lens has a refractive index of 1.4 and an Abbe number of 95; the fifth lens has a refractive index of 1.6 and an Abbe number of 75; the sixth lens has a refractive index of 1.55 and an Abbe number of 75; the seventh lens has a refractive index of 1.6 and an Abbe number of 76; the eighth lens has a refractive index of 1.4 and an Abbe number of 105; and the ninth lens has a refractive index of 1.5 and an Abbe number of 70.

[0010] Optionally, the object-facing surface of the first lens is the first mirror surface, and the image-facing surface of the first lens is the second mirror surface; the object-facing surface of the second lens is the third mirror surface, and the image-facing surface of the second lens is the fourth mirror surface; the object-facing surface of the third lens is the fifth mirror surface, and the image-facing surface of the third lens is the sixth mirror surface; the object-facing surface of the fourth lens is the seventh mirror surface, and the image-facing surface of the fourth lens is the eighth mirror surface; the object-facing surface of the fifth lens is the ninth mirror surface, and the image-facing surface of the fifth lens is the tenth mirror surface; the object-facing surface of the sixth lens is the eleventh mirror surface, and the image-facing surface of the sixth lens is the twelfth mirror surface; the object-facing surface of the seventh lens is... The thirteenth mirror surface is the surface of the seventh lens facing the image side, which is the fourteenth mirror surface; the fifteenth mirror surface is the surface of the eighth lens facing the object side, which is the sixteenth mirror surface; the seventeenth mirror surface is the surface of the ninth lens facing the object side, which is the eighteenth mirror surface; the radii of curvature of the first, second, third, fourth, fifth, sixth, eighth, tenth, and seventeenth mirror surfaces are all negative; the radii of curvature of the seventh, ninth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, sixteenth, and eighteenth mirror surfaces are all positive.

[0011] Optionally, the radius of curvature of the first mirror is -18mm, and the mirror distance between the first and second mirrors is 4mm; the radius of curvature of the second mirror is -12mm, and the mirror distance between the second and third mirrors is 0.1mm; the radius of curvature of the third mirror is -40mm, and the mirror distance between the third and fourth mirrors is 3mm; the radius of curvature of the fourth mirror is -18mm, and the mirror distance between the fourth and fifth mirrors is 0.2mm; the radius of curvature of the fifth mirror is -13mm. 0mm, the mirror distance between the fifth and sixth mirrors is 3mm; the radius of curvature of the sixth mirror is -35mm, the mirror distance between the sixth and seventh mirrors is 0.1mm; the radius of curvature of the seventh mirror is 80mm, the mirror distance between the seventh and eighth mirrors is 3mm; the radius of curvature of the eighth mirror is -75mm, the mirror distance between the eighth and ninth mirrors is 24mm; the radius of curvature of the ninth mirror is 50mm, the mirror distance between the ninth and tenth mirrors is... The radius of curvature of the tenth mirror is 4mm; the radius of curvature of the eleventh mirror is -240mm, and the mirror distance between the tenth and eleventh mirrors is 0.5mm; the radius of curvature of the eleventh mirror is 30mm, and the mirror distance between the eleventh and twelfth mirrors is 5mm; the radius of curvature of the twelfth mirror is 46mm, and the mirror distance between the twelfth and thirteenth mirrors is 5mm; the radius of curvature of the thirteenth mirror is 70mm, and the mirror distance between the thirteenth and fourteenth mirrors is 2mm; the radius of curvature of the fourteenth mirror... The radius of curvature of the fourteenth and fifteenth mirrors is 15mm, and the mirror distance between them is 12mm; the radius of curvature of the fifteenth mirror is 13mm, and the mirror distance between it and the sixteenth mirror is 5mm; the radius of curvature of the sixteenth mirror is 35mm, and the mirror distance between it and the seventeenth mirror is 15mm; the radius of curvature of the seventeenth mirror is -18mm, and the mirror distance between it and the eighteenth mirror is 6mm; the radius of curvature of the eighteenth mirror is 15mm.

[0012] Optionally, the deep ultraviolet microscope objective is applicable to wavelengths from 260 nm to 262 nm and can be used with a tube lens with a focal length of 200 mm.

[0013] Optionally, the edge of the first mirror or the outer frame can be used as an aperture stop.

[0014] According to another aspect of the present invention, a microscope is also provided, comprising any of the aforementioned deep ultraviolet microscope objectives.

[0015] This invention relates to a deep ultraviolet microscope objective. By setting the specific parameters and structure of each lens, the deep ultraviolet microscope objective achieves a magnification of -50x, an object-side field of view diameter of 0.48mm, an image-side field of view diameter of 24mm when using a 200mm focal length lens, a working distance of 13mm, and a relatively large numerical aperture (NA) of 0.55. Through independent design of the deep ultraviolet microscope objective, it is possible to better match semiconductor measurement equipment.

[0016] Furthermore, the deep ultraviolet microscope objective of this invention improves imaging quality and image-side field of view while achieving achromatic aberration in the 260nm to 262nm deep ultraviolet band, effectively correcting spherical aberration, coma, astigmatism, field curvature, distortion, axial chromatic aberration, and transverse chromatic aberration.

[0017] The above and other objects, advantages and features of this utility model will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description

[0018] The following sections will describe some specific embodiments of the present invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0019] Figure 1 This is a schematic diagram of the structure of a deep ultraviolet microscope objective lens according to an embodiment of the present invention;

[0020] Figure 2 This is a full-field, full-wavelength dot plot of a deep ultraviolet microscope objective lens according to an embodiment of the present invention;

[0021] Figure 3 This is a lateral aberration diagram of a deep ultraviolet microscope objective lens according to an embodiment of the present invention;

[0022] Figure 4 This is a full-field transfer function curve of a deep ultraviolet microscope objective lens according to an embodiment of the present invention;

[0023] Figure 5 This is an axial aberration diagram of a deep ultraviolet microscope objective lens according to an embodiment of the present invention when the pupil radius is 2.2000 mm;

[0024] Figure 6 This is a transverse chromatic aberration diagram of a deep ultraviolet microscope objective lens according to an embodiment of the present invention at a maximum field of view of 0.2850 mm; and

[0025] Figure 7This is a field curvature distortion diagram of a deep ultraviolet microscope objective lens according to an embodiment of the present invention. Detailed Implementation

[0026] This embodiment provides a deep ultraviolet microscope objective lens. By achieving independent design of the deep ultraviolet microscope objective lens, the deep ultraviolet microscope objective lens can be better matched with semiconductor measurement equipment. Figure 1 This is a schematic diagram of the structure of a microscope objective lens according to an embodiment of the present invention. Figure 1 As shown, the microscope objective lens of this embodiment includes: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9 arranged coaxially from the object side to the image side.

[0027] Among them, the first lens L1 has a concave surface facing the object and a convex surface facing the image; the second lens L2 has a concave surface facing the object and a convex surface facing the image; the third lens L3 has a concave surface facing the object and a convex surface facing the image; the fourth lens L4 has a convex surface facing the object and a convex surface facing the image; the fifth lens L5 has a convex surface facing the object and a convex surface facing the image; the sixth lens L6 has a convex surface facing the object and a concave surface facing the image; the seventh lens L7 has a convex surface facing the object and a concave surface facing the image; the eighth lens L8 has a convex surface facing the object and a concave surface facing the image; and the ninth lens L9 has a concave surface facing the object and a concave surface facing the image.

[0028] In one specific embodiment, 11.5 < fL1 / f < 14.5, 17 < fL2 / f < 20, 17.5 < fL3 / f < 20.5, 20 < fL4 / f < 23, 15.5 < fL5 / f < 18.5, 27.5 < fL6 / f < 30.5, -8.5 < fL7 / f < -5.5, 10.5 < fL8 / f < 13.5, -4.5 < fL9 / f < -1 .5, where fL1 is the focal length of the first lens L1, fL2 is the focal length of the second lens L2, fL3 is the focal length of the third lens L3, fL4 is the focal length of the fourth lens L4, fL5 is the focal length of the fifth lens L5, fL6 is the focal length of the sixth lens L6, fL7 is the focal length of the seventh lens L7, fL8 is the focal length of the eighth lens L8, fL9 is the focal length of the ninth lens L9, and f is the focal length of the deep ultraviolet microscope objective.

[0029] In a preferred embodiment, the first lens L1, the second lens L2, the third lens L3, the sixth lens L6, and the eighth lens L8 are all positive meniscus lenses with positive optical power. A positive meniscus lens is a lens composed of two surfaces with similar radii of curvature, possessing a positive focal length. Positive meniscus lenses are typically used to reduce the focal length of another lens, thereby increasing the numerical aperture. When expanding, contracting, or diverging collimating light, the light beam can be incident on the convex surface of the positive meniscus lens, thus reducing spherical aberration. When used for converging collimating light, the light beam can be incident on the concave surface of the positive meniscus lens.

[0030] The fourth lens L4 and the fifth lens L5 are both biconvex lenses with positive optical power. Positive optical power refers to the optical power of an optical system that converges light rays; its value is greater than zero. An optical system with positive optical power will converge light rays, meaning that the light beam becomes more concentrated after passing through the system. In other words, in this embodiment, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the eighth lens L8 can all converge light rays.

[0031] The seventh lens L7 is a negative meniscus lens with negative optical power. As a diverging lens with an asymmetrical curved surface structure, the negative meniscus lens has a center thickness smaller than its edge thickness and consists of a convex surface on one side and a concave surface on the other. Generally, the curvature of the convex surface of a negative meniscus lens is usually greater than that of the concave surface, forming a crescent shape that is "convex on the outside and concave on the inside." The ninth lens L9 is a biconcave lens with negative optical power. A negative optical power system makes light more divergent; that is, the light beam becomes more dispersed after passing through the system. In other words, the seventh lens L7 and the ninth lens L9 in this embodiment can make light diverge more effectively.

[0032] In one specific embodiment, the first lens L1, the third lens L3, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the ninth lens L9 all satisfy the following conditions: 1.45 < nd < 1.65, 60 < Vd < 85. The second lens L2, the fourth lens L4, and the eighth lens L8 all satisfy the following conditions: 1.25 < nd < 1.45, 85 < Vd < 110, where nd is the refractive index at a wavelength of 587.6 nm, and Vd is the Abbe number at a wavelength of 587.6 nm.

[0033] In a preferred embodiment, the specific values ​​of the refractive index and Abbe number of the first lens L1 to the ninth lens L9 can be referred to Table 1. As shown in Table 1, the refractive index of the first lens L1 is 1.5 and the Abbe number is 70; the refractive index of the second lens L2 is 1.4 and the Abbe number is 95; the refractive index of the third lens L3 is 1.55 and the Abbe number is 70; the refractive index of the fourth lens L4 is 1.4 and the Abbe number is 95; the refractive index of the fifth lens L5 is 1.6 and the Abbe number is 75; the refractive index of the sixth lens L6 is 1.55 and the Abbe number is 75; the refractive index of the seventh lens L7 is 1.6 and the Abbe number is 76; the refractive index of the eighth lens L8 is 1.4 and the Abbe number is 105; and the refractive index of the ninth lens L9 is 1.5 and the Abbe number is 70.

[0034] Table 1

[0035] First lens L1 1.5 70 Second lens L2 1.4 95 Third lens L3 1.55 70 Fourth lens L4 1.4 95 Fifth lens L5 1.6 75 Sixth lens L6 1.55 75 Seventh lens L7 1.6 76 Eighth lens L8 1.4 105 Ninth Lens L9 1.5 70

[0036] In one specific embodiment, the object-facing surface of the first lens L1 is the first mirror surface S1, and the image-facing surface of the first lens L1 is the second mirror surface S2; the object-facing surface of the second lens L2 is the third mirror surface S3, and the image-facing surface of the second lens L2 is the fourth mirror surface S4; the object-facing surface of the third lens L3 is the fifth mirror surface S5, and the image-facing surface of the third lens L3 is the sixth mirror surface S6; the object-facing surface of the fourth lens L4 is the seventh mirror surface S7, and the image-facing surface of the fourth lens L4 is the eighth mirror surface S8; the object-facing surface of the fifth lens L5 is the ninth mirror surface S9, and the fifth lens... The surface of lens L5 facing the image is the tenth mirror surface S10; the surface of lens L6 facing the object is the eleventh mirror surface S11, and the surface of lens L6 facing the image is the twelfth mirror surface S12; the surface of lens L7 facing the object is the thirteenth mirror surface S13, and the surface of lens L7 facing the image is the fourteenth mirror surface S14; the surface of lens L8 facing the object is the fifteenth mirror surface S15, and the surface of lens L8 facing the image is the sixteenth mirror surface S16; the surface of lens L9 facing the object is the seventeenth mirror surface S17, and the surface of lens L9 facing the image is the eighteenth mirror surface S18.

[0037] Furthermore, the radii of curvature of the first mirror S1, the second mirror S2, the third mirror S3, the fourth mirror S4, the fifth mirror S5, the sixth mirror S6, the eighth mirror S8, the tenth mirror S10, and the seventeenth mirror S17 are all negative; while the radii of curvature of the seventh mirror S7, the ninth mirror S9, the eleventh mirror S11, the twelfth mirror S12, the thirteenth mirror S13, the fourteenth mirror S14, the fifteenth mirror S15, the sixteenth mirror S16, and the eighteenth mirror S18 are all positive.

[0038] In a preferred embodiment, the specific values ​​of the radii of curvature of the first mirror S1 to the eighteenth mirror S18 and the mirror distance between two adjacent mirrors can be referred to Table 2. As shown in Table 2, the radius of curvature of the first mirror S1 is -18mm, and the mirror distance between the first mirror S1 and the second mirror S2 is 4mm; the radius of curvature of the second mirror S2 is -12mm, and the mirror distance between the second mirror S2 and the third mirror S3 is 0.1mm; the radius of curvature of the third mirror S3 is -40mm, and the mirror distance between the third mirror S3 and the fourth mirror S4 is 3mm; the radius of curvature of the fourth mirror S4 is -18mm, and the mirror distance between the fourth mirror S4 and the fifth mirror S5 is 0.2mm; the radius of curvature of the fifth mirror S5 is -130mm. The mirror distance between the fifth mirror S5 and the sixth mirror S6 is 3mm; the radius of curvature of the sixth mirror S6 is -35mm; the mirror distance between the sixth mirror S6 and the seventh mirror S7 is 0.1mm; the radius of curvature of the seventh mirror S7 is 80mm; the mirror distance between the seventh mirror S7 and the eighth mirror S8 is 3mm; the radius of curvature of the eighth mirror S8 is -75mm; the mirror distance between the eighth mirror S8 and the ninth mirror S9 is 24mm; the radius of curvature of the ninth mirror S9 is 50mm; and the mirror distance between the ninth mirror S9 and the tenth mirror S10 is 4mm.

[0039] The radius of curvature of the tenth mirror S10 is -240mm, and the mirror distance between the tenth mirror S10 and the eleventh mirror S11 is 0.5mm; the radius of curvature of the eleventh mirror S11 is 30mm, and the mirror distance between the eleventh mirror S11 and the twelfth mirror S12 is 5mm; the radius of curvature of the twelfth mirror S12 is 46mm, and the mirror distance between the twelfth mirror S12 and the thirteenth mirror S13 is 5mm; the radius of curvature of the thirteenth mirror S13 is 70mm, and the mirror distance between the thirteenth mirror S13 and the fourteenth mirror S14 is 2mm; the radius of curvature of the fourteenth mirror S14 is... The radius of curvature of the fourteenth mirror S14 is 15mm, and the mirror distance between the fourteenth mirror S14 and the fifteenth mirror S15 is 12mm; the radius of curvature of the fifteenth mirror S15 is 13mm, and the mirror distance between the fifteenth mirror S15 and the sixteenth mirror S16 is 5mm; the radius of curvature of the sixteenth mirror S16 is 35mm, and the mirror distance between the sixteenth mirror S16 and the seventeenth mirror S17 is 15mm; the radius of curvature of the seventeenth mirror S17 is -18mm, and the mirror distance between the seventeenth mirror S17 and the eighteenth mirror S18 is 6mm; the radius of curvature of the eighteenth mirror S18 is 15mm.

[0040] Table 2

[0041]

[0042]

[0043] By setting the specific parameters and structures of each lens in Tables 1 and 2 above, the microscope objective can achieve a magnification of -50x, an object-side field-of-view diameter of 0.48mm, an image-side field-of-view diameter of 24mm when using a 200mm focal length tube lens, a working distance of 13mm, and a relatively large numerical aperture (NA) of 0.55. Through the independent design of the deep ultraviolet microscope objective, the deep ultraviolet microscope objective can be better matched with semiconductor measurement equipment.

[0044] In a preferred embodiment, the edge or outer frame of the first mirror S1 serves as an aperture stop. The aperture stop limits the aperture through which the light beam passes. Furthermore, it should be noted that since the object plane is planar, its radius of curvature is infinite. Also, the mirror distance from the object plane to the first mirror S1 can be 13 mm. The mirror distance between the eighteenth mirror S18 and the image plane is infinite.

[0045] Figure 2 This is a full-field, full-wavelength dot plot of a microscope objective lens according to an embodiment of the present invention. Figure 2 The focusing of light with wavelengths from 0.26 μm to 0.262 μm at the focal point is shown under different image plane fields of view. The object plane half-field of view of field of view (1) is 0.24 mm, that of field of view (2) is 0.18 mm, and that of field of view (3) is 0 mm. Since the magnification of the objective lens is -50x, the image plane field of view is the object plane half-field of view * 2 * 50. The image plane fields of view corresponding to fields of view (1), (2), and (3) are 24 mm, 18 mm, and 0 mm, respectively. The test data are as follows: Airy disk radius (diffraction limit) is 60.432 μr, RMS radius (root mean square) at field of view (1) is 22.56 μr, GEO radius (maximum) is 72.529 μr, RMS radius at field of view (2) is 13.141 μr, GEO radius is 37.672 μr, RMS radius at field of view (3) is 4.693 μr, GEO radius is 9.472 μr.

[0046] The RMS radius, also known as the root mean square spot radius, is an indicator used to describe the size of a light beam. It is the spot radius obtained by taking the square root of the second average of the light intensity distribution. The GEO radius (Geometric Optical Radius) represents the radius of the smallest central circle that contains all light rays. Specifically, the GEO radius is the radius of the smallest central circle that allows all light rays to fall within its range. Figure 2As can be seen, the focused spots of light of different wavelengths in different fields of view are all within the Airy disk range, indicating that the microscope objective of this embodiment has excellent focusing effect. The RMS radius of the dot plot is better than the diffraction limit, indicating that the aberration control of the deep ultraviolet microscope objective of this embodiment is good.

[0047] Figure 3 This is a lateral aberration diagram of a microscope objective lens according to an embodiment of the present invention. Figure 3 In the diagram, the horizontal coordinates Px and Py represent the entrance pupil position, and the vertical coordinates ex and ey represent the beam distribution (lateral aberration) at the image plane. y represents the meridional direction, and x represents the sagittal direction. Figure 3 The diagram illustrates the lateral aberrations of light of different wavelengths at different entrance pupil positions when the image plane field of view is 24mm, 18mm, and 0mm. Fields of view (1), (2), and (3) correspond to image plane fields of view of 24mm, 18mm, and 0mm, respectively. Figure 3 As shown, with image plane fields of view of 24mm, 18mm and 0mm, the lateral aberrations of light with wavelengths of 0.261μm, 0.26μm and 0.262μm at different entrance pupil positions are all within ±0.1mrad, indicating that the aberration balance is very good and the imaging is excellent.

[0048] Figure 4 This is a full-field transfer function curve of a microscope objective lens according to an embodiment of the present invention. Figure 4 The ordinate represents the magnitude of the normalized transfer function, and the abscissa represents the angular frequency, with units of lp / mr. The outermost line is the transfer function curve of the system in the diffraction-limited state. For example... Figure 4 As shown, the transfer function curves of the microscope objective lens in this embodiment, with image plane fields of view of 24mm, 18mm and 0mm, for each wavelength meridional plane and sagittal plane, show that the on-axis field-of-view transfer function curve and the off-axis field-of-view transfer function curve are close to the diffraction limit, indicating that the optical system has high imaging contrast across the entire field of view and distinct image layering.

[0049] Figure 5 This is an axial aberration diagram of a microscope objective lens according to an embodiment of the present invention when the pupil radius is 8.5596 mm. Figure 5 The ordinate represents the normalized pupil coordinates, and the abscissa represents the axial aberration, in mm. Figure 5 The diagram shows the axial aberrations of different wavelengths of light at a pupil radius of 8.5596 mm. Figure 5 As shown, the axial aberrations at each wavelength are all less than 0.008 mm, indicating relatively small axial aberrations. It should be noted that axial aberrations can also be referred to as longitudinal aberrations, axial chromatic aberrations, or longitudinal chromatic aberrations.

[0050] Figure 6This is a transverse chromatic aberration diagram of a microscope objective lens according to an embodiment of the present invention when the maximum field of view is 0.24 mm. Figure 6 The vertical axis represents the field of view in mm, and the horizontal axis represents the lateral aberration in mr. Figure 6 The diagram shows the transverse chromatic aberration of light of different wavelengths at a maximum field of view of 0.24 mm, where the maximum field of view of 0.24 mm refers to the object plane half field of view. Figure 6 The curve in the figure represents the size of the diffraction-limited Airy disk of the system, such as Figure 6 As shown, the transverse chromatic aberration of light of different wavelengths at a maximum field of view of 0.24 mm remains within the size of the diffraction-limited Airy disk of the system, indicating good control of transverse chromatic aberration.

[0051] Figure 7 This is a field curvature distortion diagram of a microscope objective lens according to an embodiment of the present invention. Figure 7 The left side of the graph is the field curvature diagram, with the vertical axis representing the field of view in the direction of the incident light from the objective lens, and the horizontal axis representing the field curvature value in μm. Figure 7 The right-hand side of the graph shows the distortion plot. The vertical axis represents the image-side field of view during imaging, and the horizontal axis represents the distortion percentage. The data obtained when testing the field curvature plot are as follows: maximum field of view 0.24 mm, sagittal field curvature 0.0066 mm, meridional field curvature 0.0119 mm. The data obtained when testing the distortion plot are as follows: maximum field of view 0.24 mm, maximum distortion percentage 0.4276%. Figure 7 As shown, the field curvature values ​​in both the meridional and sagittal planes at each wavelength are below 0.03 mm, resulting in clear imaging across the entire field of view without introducing additional field curvature. The distortion across the entire field of view at each wavelength is within 0.5%, indicating good distortion correction.

[0052] This embodiment also provides a microscope, which includes the deep ultraviolet microscope objective of any of the above embodiments. In a specific embodiment, by setting the specific parameters and structure of each lens, the magnification of the deep ultraviolet microscope objective is -50x, the object-side field of view diameter is 0.48mm, the image-side field of view diameter is 24mm when using a 200mm focal length tube lens, the working distance is 13mm, and the corresponding numerical aperture NA is relatively large, at 0.55. By realizing the independent design of the deep ultraviolet microscope objective, the deep ultraviolet microscope objective can be better matched with semiconductor measurement equipment; while improving the imaging quality and image-side field of view, achromatic aberration in the 260nm to 262nm deep ultraviolet band is achieved, and spherical aberration, coma, astigmatism, field curvature, distortion, axial chromatic aberration, and transverse chromatic aberration are well corrected.

[0053] Those skilled in the art should understand that, unless otherwise specified, the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," "clockwise," and "counterclockwise" used to indicate orientation or positional relationships in the embodiments of this utility model are merely for the convenience of describing and understanding the technical solution of this utility model, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0054] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," etc., may explicitly or implicitly include at least one of that feature, that is, include one or more of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. When a feature "includes or contains" one or more of the features it encompasses, unless otherwise specifically described, this indicates that other features are not excluded and may be further included.

[0055] Unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art should be able to understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0056] Furthermore, in the description of this embodiment, "above" or "below" the second feature can include direct contact between the first and second features, or it can include contact between the first and second features through another feature between them. That is, in the description of this embodiment, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "below" of the second feature can mean the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0057] In the description of this embodiment, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] Therefore, those skilled in the art should recognize that although many exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A deep ultraviolet microscope objective, characterized in that, include: The first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, and ninth lens are arranged coaxially from the object side to the image side. The first lens has a concave surface facing the object and a convex surface facing the image; the second lens has a concave surface facing the object and a convex surface facing the image; the third lens has a concave surface facing the object and a convex surface facing the image; the fourth lens has a convex surface facing the object and a convex surface facing the image; the fifth lens has a convex surface facing the object and a convex surface facing the image; the sixth lens has a convex surface facing the object and a concave surface facing the image; the seventh lens has a convex surface facing the object and a concave surface facing the image; the eighth lens has a convex surface facing the object and a concave surface facing the image; and the ninth lens has a concave surface facing the object and a concave surface facing the image.

2. The deep ultraviolet microscope objective according to claim 1, characterized in that, 11.5<fL1 / f<14.5, 17<fL2 / f<20, 17.5<fL3 / f<20.5, 20<fL4 / f<23, 15.5<fL5 / f<1 8.5, 27.5<fL6 / f<30.5, -8.5<fL7 / f<-5.5, 10.5<fL8 / f<13.5, -4.5<fL9 / f<-1.5, Where fL1 is the focal length of the first lens, fL2 is the focal length of the second lens, fL3 is the focal length of the third lens, fL4 is the focal length of the fourth lens, fL5 is the focal length of the fifth lens, fL6 is the focal length of the sixth lens, fL7 is the focal length of the seventh lens, fL8 is the focal length of the eighth lens, fL9 is the focal length of the ninth lens, and f is the focal length of the deep ultraviolet microscope objective.

3. The deep ultraviolet microscope objective according to claim 2, characterized in that, The first lens, the second lens, the third lens, the sixth lens, and the eighth lens are all positive meniscus lenses with positive optical power; Both the fourth lens and the fifth lens are biconvex lenses with positive optical power; The seventh lens is a negative meniscus lens with negative optical power; The ninth lens is a biconcave lens with negative optical power.

4. The deep ultraviolet microscope objective according to claim 3, characterized in that, The first lens, the third lens, the fifth lens, the sixth lens, the seventh lens, and the ninth lens all satisfy the following conditions: 1.45 < nd < 1.65, 60 < Vd < 85; The second lens, the fourth lens, and the eighth lens all satisfy the following conditions: 1.25 < nd < 1.45, 85 < Vd < 110, where nd is the refractive index at a wavelength of 587.6 nm and Vd is the Abbe number at a wavelength of 587.6 nm.

5. The deep ultraviolet microscope objective according to claim 4, characterized in that, The first lens has a refractive index of 1.5 and an Abbe number of 70. The second lens has a refractive index of 1.4 and an Abbe number of 95. The third lens has a refractive index of 1.55 and an Abbe number of 70. The fourth lens has a refractive index of 1.4 and an Abbe number of 95. The fifth lens has a refractive index of 1.6 and an Abbe number of 75. The sixth lens has a refractive index of 1.55 and an Abbe number of 75. The seventh lens has a refractive index of 1.6 and an Abbe number of 76. The emissivity of the eighth lens is 1.4, and the Abbe number is 105. The ninth lens has a refractive index of 1.5 and an Abbe number of 70.

6. The deep ultraviolet microscope objective according to claim 5, characterized in that, The object-facing surface of the first lens is the first mirror surface, and the image-facing surface of the first lens is the second mirror surface; the object-facing surface of the second lens is the third mirror surface, and the image-facing surface of the second lens is the fourth mirror surface; the object-facing surface of the third lens is the fifth mirror surface, and the image-facing surface of the third lens is the sixth mirror surface. The object-facing surface of the fourth lens is the seventh mirror surface, and the image-facing surface of the fourth lens is the eighth mirror surface; the object-facing surface of the fifth lens is the ninth mirror surface, and the image-facing surface of the fifth lens is the tenth mirror surface. The object-facing surface of the sixth lens is the eleventh mirror surface, and the image-facing surface of the sixth lens is the twelfth mirror surface; the object-facing surface of the seventh lens is the thirteenth mirror surface, and the image-facing surface of the seventh lens is the fourteenth mirror surface; the object-facing surface of the eighth lens is the fifteenth mirror surface, and the image-facing surface of the eighth lens is the sixteenth mirror surface; the object-facing surface of the ninth lens is the seventeenth mirror surface, and the image-facing surface of the ninth lens is the eighteenth mirror surface. The radii of curvature of the first, second, third, fourth, fifth, sixth, eighth, tenth, and seventeenth mirrors are all negative; the radii of curvature of the seventh, ninth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, sixteenth, and eighteenth mirrors are all positive.

7. The deep ultraviolet microscope objective according to claim 6, characterized in that, The radius of curvature of the first mirror is -18mm, and the mirror distance between the first mirror and the second mirror is 4mm; The radius of curvature of the second mirror is -12mm, and the mirror distance between the second mirror and the third mirror is 0.1mm; The radius of curvature of the third mirror is -40mm, and the mirror distance between the third mirror and the fourth mirror is 3mm; The radius of curvature of the fourth mirror is -18mm, and the mirror distance between the fourth mirror and the fifth mirror is 0.2mm; The radius of curvature of the fifth mirror is -130mm, and the mirror distance between the fifth mirror and the sixth mirror is 3mm; The radius of curvature of the sixth mirror is -35mm, and the mirror distance between the sixth mirror and the seventh mirror is 0.1mm; The radius of curvature of the seventh mirror is 80mm, and the mirror distance between the seventh mirror and the eighth mirror is 3mm; The radius of curvature of the eighth mirror is -75mm, and the mirror distance between the eighth mirror and the ninth mirror is 24mm; The radius of curvature of the ninth mirror is 50mm, and the mirror distance between the ninth mirror and the tenth mirror is 4mm; The radius of curvature of the tenth mirror is -240mm, and the mirror distance between the tenth mirror and the eleventh mirror is 0.5mm. The radius of curvature of the eleventh mirror is 30mm, and the mirror distance between the eleventh mirror and the twelfth mirror is 5mm. The radius of curvature of the twelfth mirror is 46mm, and the mirror distance between the twelfth mirror and the thirteenth mirror is 5mm. The radius of curvature of the thirteenth mirror is 70mm, and the mirror distance between the thirteenth mirror and the fourteenth mirror is 2mm. The radius of curvature of the fourteenth mirror is 15mm, and the mirror distance between the fourteenth mirror and the fifteenth mirror is 12mm; The radius of curvature of the fifteenth mirror is 13mm, and the mirror distance between the fifteenth mirror and the sixteenth mirror is 5mm; The radius of curvature of the sixteenth mirror is 35mm, and the mirror distance between the sixteenth mirror and the seventeenth mirror is 15mm; The radius of curvature of the seventeenth mirror is -18mm, and the mirror distance between the seventeenth mirror and the eighteenth mirror is 6mm; The radius of curvature of the eighteenth mirror is 15mm.

8. The deep ultraviolet microscope objective according to claim 7, characterized in that, The deep ultraviolet microscope objective is applicable to wavelengths from 260nm to 262nm, and the compatible tube lens has a focal length of 200mm.

9. The deep ultraviolet microscope objective according to claim 1, characterized in that, The edge of the first mirror or the outer frame serves as an aperture stop.

10. A microscope comprising a deep ultraviolet microscope objective according to any one of claims 1 to 9.

Images