Projection lithography objective lens and lithography machine

Abstract

The present invention provides a projection lithography objective lens and a lithography machine. Among them, at least one lens in the first lens group is aspherical, and the aspherical surface is arranged toward the object plane, so as to shorten the conjugate distance of the objective lens and make the objective lens structure more compact. The first negative lens of the fifth lens group and the first positive lens of the sixth lens group are arranged adjacent to each other to form a close double-separation lens group, which can correct the chromatic aberration of the field of view. The second negative lens of the seventh lens group and the fourth positive lens of the eighth lens group are arranged adjacent to each other to form a close double-separation lens group, which further corrects the chromatic aberration of the field of view and improves the imaging quality of the field of view. At least one lens in the third lens group and the seventh lens group is aspherical. Because the aspherical surface increases the degree of freedom of optimization compared to the spherical surface, one aspherical surface can in principle replace the aberration correction effect of 2‑3 spherical lenses. Under the premise of ensuring resolution, the number of lenses can be reduced, making the projection lithography objective lens structure more compact and reducing costs.

Description

Technical Field

[0001] The present invention relates to the technical field of photolithography machine manufacturing, and in particular to a projection photolithography objective lens and a photolithography machine. Background Art

[0002] Optical exposure equipment, also known as photolithography, utilizes the principle of optical projection imaging to transfer the integrated circuit (IC) pattern on a mask onto a coated silicon wafer in a distributed, repetitive, or scanning manner, thereby fabricating semiconductor devices. However, as the integration density of integrated circuit devices continues to increase, the resolution requirements for photolithography lenses are also increasing.

[0003] It is well known that improving the resolution of lithography can be achieved by shortening the wavelength, increasing the numerical aperture (NA), reducing the process factor, etc. However, a large numerical aperture brings all-round challenges to the design of the projection optical system. In a pure refractive optical system used for projection exposure, the weight and size of the projection optical system tend to increase with the increase of the numerical aperture. In semiconductor lithography machines, especially fully refractive projection exposure equipment, the lithography projection objective lens accounts for a large proportion of the overall height of the lithography machine. In the case of limited space in the entire machine volume, the increase in numerical aperture will not only increase the difficulty of manufacturing the optical lens, but also increase the manufacturing cost.

[0004] Therefore, it is necessary to design a new projection lithography objective lens and a lithography machine to reduce the size of the lithography projection objective lens and the number of lenses used. Summary of the Invention

[0005] The object of the present invention is to provide a projection lithography objective lens and a lithography machine, so as to solve the problem of how to reduce the size of the lithography projection objective lens and the number of lenses used.

[0006] In order to solve the above technical problems, the present invention provides a projection lithography objective lens, comprising: a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, a sixth lens group, a seventh lens group, an eighth lens group, a ninth lens group and a tenth lens group arranged in sequence along an optical path; wherein,

[0007] At least one lens in the first lens group is aspherical, and the aspherical surface is arranged toward the object plane; the fifth lens group includes a first negative lens, the sixth lens group includes a first positive lens, and the first negative lens and the first positive lens are arranged adjacent to each other; the seventh lens group includes a second negative lens, the eighth lens group includes a second positive lens, and the second negative lens and the second positive lens are arranged adjacent to each other; at least one lens in each of the third lens group and the seventh lens group is aspherical.

[0008] Optionally, in the projection lithography objective lens, the sixth lens group further includes a third positive lens, an aperture stop and the fourth positive lens arranged in sequence; wherein the third positive lens and the fourth positive lens are symmetrically distributed about the aperture stop.

[0009] Optionally, in the projection lithography objective, the first negative lens and the first positive lens form a first close-contact double-separated lens group, and the second negative lens and the second positive lens form a second close-contact double-separated lens group; wherein, the first close-contact double-separated lens group and the second close-contact double-separated lens group are symmetrically distributed about the aperture stop.

[0010] Optionally, in the projection lithography objective lens, the first lens group includes at least one meniscus negative lens, and the side of the meniscus negative lens facing the object plane is aspherical.

[0011] Optionally, in the projection lithography objective lens, the ninth lens group includes at least one meniscus negative lens, and the curvature direction of the meniscus negative lens is toward the image plane.

[0012] Optionally, in the projection lithography objective lens, the lenses in the first lens group, the third lens group, the fifth lens group, the seventh lens group and the ninth lens group are all negative lenses.

[0013] Optionally, in the projection lithography objective lens, the lenses in the second lens group, the fourth lens group, the sixth lens group, the eighth lens group and the tenth lens group are all positive lenses.

[0014] Optionally, in the projection lithography objective lens, the material of the lens in the projection lithography objective lens includes ultraviolet high-transmittance optical glass with a refractive index greater than 1.61 at the working wavelength, and ultraviolet high-transmittance optical glass with a refractive index less than 1.51 at the working wavelength.

[0015] Optionally, in the projection lithography objective lens, the projection lithography objective lens further includes an object plane plate and an image plane plate; wherein, one side of the object plane plate is close to the object plane, and the other opposite side is close to the first lens group; one side of the image plane plate is close to the image plane, and the other opposite side is close to the tenth lens group.

[0016] Optionally, in the projection lithography objective lens, the optical focal lengths of the object plane plate and the image plane plate are zero.

[0017] Based on the same inventive concept, the present invention also provides a lithography machine, which includes the projection lithography objective lens.

[0018] In summary, the present invention provides a projection lithography objective lens and a lithography machine, wherein the projection lithography objective lens comprises: a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, a sixth lens group, a seventh lens group, an eighth lens group, a ninth lens group, and a tenth lens group, which are sequentially arranged along an optical path. At least one lens in the first lens group is aspherical, and the aspherical surface is arranged toward the object plane to shorten the conjugate distance of the objective lens and make the objective lens structure more compact. The fifth lens group comprises a first negative lens, the sixth lens group comprises a first positive lens, and the first negative lens and the first positive lens are arranged adjacent to each other to form a close-fitting double-separated lens group, which can correct chromatic aberration of the field of view. The seventh lens group comprises a second negative lens, the eighth lens group comprises a fourth positive lens, and the second negative lens and the fourth positive lens are arranged adjacent to each other to form a close-fitting double-separated lens group, which further corrects chromatic aberration of the field of view and improves the imaging quality of the field of view. At least one lens in each of the third and seventh lens groups is aspherical. Because aspheric surfaces have increased degrees of freedom in optimization compared to spherical surfaces, one aspheric surface can, in principle, replace the aberration correction effect of 2-3 spherical lenses. While ensuring resolution, the number of lenses can be reduced, making the projection lithography objective lens structure more compact and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of a projection lithography objective lens in embodiment 1 of the present invention;

[0020] Figure 2 is a modulation transfer function curve diagram in the first embodiment of the present invention;

[0021] Figure 3 This is the image wave aberration distribution diagram at the central reference wavelength of 365.3 nm in Example 1 of the present invention;

[0022] Figure 4 is a distorted image surface distribution diagram in the first embodiment of the present invention;

[0023] Figure 5 is a color difference curve diagram in Example 1 of the present invention;

[0024] Figure 6 is an aberration curve diagram in Example 1 of the present invention;

[0025] Figure 7 Schematic diagram of the structure of a projection lithography objective lens in embodiment 2 of the present invention;

[0026] Figure 8 is a modulation transfer function curve diagram in the second embodiment of the present invention;

[0027] Figure 9This is the image wave aberration distribution diagram at the central reference wavelength of 365.3 nm in Example 2 of the present invention;

[0028] Figure 10 is a distorted image plane distribution diagram in the second embodiment of the present invention;

[0029] Figure 11 is a color difference curve diagram in Example 2 of the present invention;

[0030] Figure 12 This is an aberration curve diagram in Example 2 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the objects, advantages and features of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis required to be shown in each drawing is different, and sometimes different scales are used. It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third" and the like in the specification are only used to distinguish between the various components, elements, steps, etc. in the specification, and are not used to represent the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0032] <Example 1>

[0033] In order to solve the above technical problems, the present invention provides a projection lithography objective lens, please refer to Figure 1 , including: a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, a sixth lens group G6, a seventh lens group G7, an eighth lens group G8, a ninth lens group G9 and a tenth lens group G10 arranged in sequence along the optical path.

[0034] At least one lens in the first lens group G1 is aspherical, and the aspherical surface is positioned toward the object plane. Because aspherical surfaces offer increased degrees of freedom for optimization compared to spherical surfaces, a single aspherical lens can, in principle, replace the aberration correction effect of two or three spherical lenses. This reduces the number of lenses while maintaining resolution, making the projection lithography objective lens structure more compact and reducing costs. Furthermore, the first lens group G1 includes at least one meniscus negative lens 2, with the side of the meniscus negative lens 2 facing the object plane being aspherical. Optionally, the first lens group G1 provided in this embodiment includes a single meniscus negative lens 2.

[0035] The second lens group G2 has a positive combined optical power and is optionally composed of two lenses, namely a biconvex positive lens 3 and a biconvex positive lens 4.

[0036] At least one lens in the third lens group G3 is aspherical, further reducing the number of lenses used, making the objective lens structure more compact and reducing costs. Optionally, the third lens group G3 consists of four lenses: meniscus negative lenses 5 and 6, a biconcave negative lens 7, and a biconcave negative lens 8. The fourth lens group G4 has positive combined optical power and optionally consists of two lenses: a biconvex positive lens 9 and a biconvex positive lens 10.

[0037] The fifth lens group G5 includes a first negative lens 12, and the sixth lens group G6 includes a first positive lens 13, with the first negative lens 12 and the first positive lens 13 being arranged adjacent to each other. That is, the first negative lens 12 is the last lens in the fifth lens group G5, and the first positive lens 13 is the first lens in the sixth lens group G6. The two are closely connected, forming a first close-contact double-separated lens group to correct field chromatic aberration. Furthermore, the optical powers of the first negative lens 12 and the first positive lens 13 do not compensate for each other, but retain a certain residual combined optical power. In terms of material selection, the Abbe constant (dispersion) difference of the optical materials of the first negative lens 12 and the first positive lens 13 is as large as possible. Preferably, the material of the first negative lens 12 is flint glass, and the material of the first positive lens 13 is crown glass.

[0038] Optionally, the fifth lens group G5 includes a biconcave negative lens 11 and a biconcave negative lens 12. The first negative lens is a biconcave negative lens 12. The sixth lens group G6 also includes a third positive lens 14, an aperture stop a, and a fourth positive lens 15, which are arranged in sequence. The first positive lens 13 is a biconvex positive lens, the third positive lens 14 is a biconvex positive lens, and the fourth positive lens 15 is a biconvex positive lens. The third positive lens 14 and the fourth positive lens 15 are symmetrically arranged about the aperture stop a to improve imaging quality.

[0039] The seventh lens group G7 includes a second negative lens 16, and the eighth lens group G8 includes a second positive lens 17. The second negative lens 16 and the second positive lens 17 are arranged adjacent to each other; that is, the second negative lens 16 is the last lens in the seventh lens group G7, and the second positive lens 17 is the first lens in the eighth lens group G8. The two are closely connected, forming a second close-contact double-separated lens group to further correct field chromatic aberration. Furthermore, the optical powers of the second negative lens 16 and the second positive lens 17 do not compensate for each other, but retain a certain residual combined optical power. In terms of material selection, the difference in the Abbe constant (dispersion) of the optical materials of the second negative lens and the second positive lens is as large as possible. Preferably, the material of the second negative lens is flint glass, and the material of the second positive lens is crown glass.

[0040] Furthermore, the first close-contact double-separated lens group and the second close-contact double-separated lens group are symmetrically distributed about the aperture stop a to improve imaging quality. Furthermore, at least one lens in the seventh lens group G7 is aspherical, further reducing the number of lenses, making the objective lens structure more compact and reducing costs. Optionally, the seventh lens group G7 has a negative combined optical power and consists of a meniscus negative lens 16. The eighth lens group G8 has a positive combined optical power and consists of three lenses: a biconvex positive lens 17, a biconvex positive lens 18, and a convex-concave positive lens 19.

[0041] The ninth lens group G9 includes at least one negative meniscus lens 20, with the curvature of the meniscus lens 20 directed toward the image plane. Optionally, the ninth lens group G9 consists of two lenses: the negative meniscus lens 20 and the negative meniscus lens 21. The tenth lens group G10 has positive optical power and consists of a single convex-concave positive lens 22.

[0042] Furthermore, the lenses in the first lens group G1, the third lens group G3, the fifth lens group G5, the seventh lens group G7, and the ninth lens group G9 are all negative lenses, that is, the combined optical power of each lens group is negative. The lenses in the second lens group G2, the fourth lens group G4, the sixth lens group G6, the eighth lens group G8, and the tenth lens group G10 are all positive lenses, that is, the combined optical power of each lens group is positive.

[0043] To protect the lenses, the projection lithography objective also includes an object plate 1 and an image plate 23. One side of the object plate 1 is close to the object plane, and the opposite side is close to the first lens group G1. One side of the image plate 23 is close to the image plane, and the opposite side is close to the tenth lens group G10. The optical power of the object plate 1 and the image plate 23 is zero.

[0044] Furthermore, the materials used for the lenses in projection lithography objectives include high-UV-transmittance optical glasses with a refractive index greater than 1.61 at the operating wavelength center reference wavelength of 365.3nm, such as flint glass; and high-UV-transmittance optical glasses with a refractive index less than 1.51 at the operating wavelength center reference wavelength of 365.3nm, such as crown glass. Ultraviolet-transmittance optical glasses undergo specific changes under laser irradiation. First, they experience changes in transmittance (solarization), which primarily manifests as structural changes (densification), geometric changes, thickness reduction, and physical changes (densification), resulting in increased density. Second, they experience changes in optical path difference (primarily due to changes in refractive index caused by density changes). These changes are influenced by the size of the illuminated area, the dose, and the amount of impurities (OH-content), resulting in an increase in the refractive index in the compacted areas and a decrease in the rarefaction areas. Consequently, under UV laser irradiation, the material's refractive index and transmittance vary with the irradiation dose, causing changes in the objective image quality and impacting the life of the lithography tool.

[0045] Therefore, the ultraviolet high-transmittance optical glass selected in this embodiment is used to make the projection lithography objective lens have the characteristic of stable imaging over time. That is, the transmittance of the projection lithography objective lens can be reduced in attenuation rate over time during operation, especially when it is used for exposure of high-productivity wafers. At the same time, this embodiment uses three aspheric lenses, and the aspheric surfaces are respectively located on the front surface of the biconcave negative lens 2, the front surface of the biconcave negative lens 8, and the rear surface of the biconcave negative lens 16. Among them, all the aspheric surfaces are concave surfaces with good processing performance, and the aspheric surface deviation reaches the processing level of the optical industry <1mm. Therefore, the projection lithography objective lens provided by this embodiment not only reduces the total number of lenses in the entire system, making the entire projection lithography objective lens structure simpler and more compact, so as to effectively control the incident height and lens size of the light beam at each lens, but also corrects the chromatic aberration of the field of view, thereby improving the imaging quality.

[0046] In order to verify the technical effect of this embodiment, the applicant Figure 1 The projection lithography objective lens shown in the figure is simulated and tested. Among them, the total length of the lithography projection objective lens is 900mm, its maximum lens semi-aperture is 99.2mm, the object side working distance of the projection objective lens is 32mm, and the image side working distance is 8mm. It is suitable for the i-line ultraviolet spectrum range, the maximum spectrum half-height full width is 2.5nm, the system magnification β is 1 / 5, the numerical aperture of the image side is 0.6, the image side half-field height is 15.56mm, and the achievable rectangular exposure field size is: 22mmx22mm. Among them, Figure 1The projection lithography objective shown in the figure implements a bi-telecentric structure. The chief rays of each field of view on the object side are incident on the front surface of the first parallel plate approximately parallel to the optical axis. The chief rays of each field of view on the image side are emitted approximately parallel to the optical axis and converge on the image plane. The angles with the optical axis are 6.7 mrad on the object side and 2.7 mrad on the image side. Specific experimental parameters are shown in the table below:

[0047] Table 1 Design values ​​of embodiment 1

[0048]

[0049] Table 2 Design values ​​of Example 1

[0050]

[0051]

[0052] Table 3 Aspheric coefficients of Example 1

[0053] Aspheric Aspheric Surface_4A Aspheric Surface_14A Aspheric_34A Radius of curvature -102.45496182715 -626.533068308 212.383335351049 K 0 0 0 A 1.62078476732907e-008 -2.50756036630493e-007 1.04588595513349e-007 B 8.61088007493735e-013 -5.18927052794122e-012 2.8687725938492e-013 C 4.40069374360282e-017 9.00815961904729e-016 -3.34689309489849e-017 D 1.56289223724333e-020 2.21612399738271e-019 -2.96919984411345e-021 E -1.79290508885724e-024 1.55394339716073e-023 1.65445132567928e-026 F 2.06216768039985e-028 -6.75185769382601e-027 -1.54728937767006e-029

[0054] Table 4 Refractive index of materials in Example 1

[0055] Material Refractive index@365.30nm Air 1 SFSL5Y_OHARA 1.504001 N5742_NIKON 1.612550 N5859_NIKON 1.614435 NIFSS_NIKON 1.474514 PBL6Y_OHARA 1.559515

[0056] In Table 2, a positive radius value indicates that the center of curvature is to the right of the surface, and a negative radius value indicates that the center of curvature is to the left of the surface. A radius of curvature of 1.00E+18 represents a flat surface. The thickness of an optical element or the spacing between two optical elements is the on-axis distance to the next surface. All dimensions are in millimeters. Table 3 shows the aspheric coefficients corresponding to the surface numbers in Table 2. Furthermore, the calculation formula for the aspheric coefficients of the projection lithography objective lens provided in this embodiment is:

[0057]

[0058] in, x represents the coordinate value in the X direction, y represents the coordinate value in the Y direction, z represents the axial sagittal height in the Z direction, the X direction, Y direction, and Z direction conform to the Cartesian coordinate system, k represents the cone coefficient of the best-fit cone, c represents the curvature (curv) of the best-fit sphere, A, B, C, D, E, F, G, H, and J all represent aspheric coefficients, where, in this embodiment, G=0, H=0, and J=0.

[0059] Table 4 shows the relative refractive index data of the optical materials used in this embodiment relative to air at a wavelength of 365.3 nm.

[0060] According to the test results: Figure 2is the Modulation Transfer Function (MTF) curve, from Figure 2 It can be seen from the figure that the multi-color modulation transfer function is very close to the diffraction limit, which shows that the visual quality produced by the lithography projection objective lens provided by this embodiment is very good. Figure 3 is the image wavefront aberration (WFE) distribution diagram at the central reference wavelength of 365.3nm, Figure 4 is the distorted image distribution diagram, Figure 5 is the color difference curve, Figure 6 It can be seen that the wavefront aberration, distortion correction effect, chromatic aberration correction effect and aberration correction effect produced by the lithography projection objective lens provided in this embodiment are all very good.

[0061] Therefore, the projection lithography objective provided in this embodiment not only reduces the total number of lenses in the entire system and reduces costs, making the entire projection lithography objective structure simpler and more compact, thereby effectively controlling the incident height and lens size of the light beam on each lens, but also corrects chromatic aberration of the field of view and improves imaging quality.

[0062] Based on the same inventive concept, this embodiment further provides a lithography machine, which includes a projection lithography objective lens.

[0063] <Example 2>

[0064] Based on the same inventive concept, this embodiment provides a projection lithography objective lens, see Figure 7 The projection lithography objective lens includes: a first lens group G1', a second lens group G2', a third lens group G3', a fourth lens group G4', a fifth lens group G5', a sixth lens group G6', a seventh lens group G7', an eighth lens group G8', a ninth lens group G9', and a tenth lens group G10', which are arranged in sequence along the optical path. At least one lens in the first lens group G1' is aspherical, and the aspheric surface is arranged toward the object plane to shorten the conjugate distance of the objective lens and make the objective lens structure more compact. The fifth lens group G5' includes a first negative lens 14', and the sixth lens group G6' includes a first positive lens 15'. The first negative lens 14' and the first positive lens 15' are arranged adjacent to each other to form a close-contact double-separated lens group, which can correct chromatic aberration of the field of view. The seventh lens group G7' includes a second negative lens 18', and the eighth lens group G8' includes a fourth positive lens 19'. The second negative lens 18' and the fourth positive lens 19' are arranged adjacent to each other, forming a close-fitting double-separated lens group. This further corrects chromatic aberrations in the field of view and improves imaging quality. At least one lens in each of the third lens group G3' and the seventh lens group G7' is aspherical. Because aspherical surfaces offer greater flexibility in optimization compared to spherical surfaces, a single aspherical surface can, in principle, replace the aberration correction effect of two or three spherical lenses. This reduces the number of lenses while maintaining resolution, resulting in a more compact objective lens structure and lower costs.

[0065] Further, such as Figure 7 As shown, the first lens group G1' has negative optical focal power and consists of a meniscus negative lens 2'. The second lens group G2' has a positive combined optical focal power and consists of three lenses, namely a concave-convex positive lens 3', a biconvex positive lens 4' and a convex-concave positive lens 5'. The third lens group G3' has a negative combined optical focal power and consists of three lenses, namely a convex-concave negative lens 6', a biconcave negative lens 7' and a biconcave negative lens 8'. The fourth lens group G4' has a positive combined optical focal power and consists of three lenses, namely a concave-convex positive lens 9', a biconvex positive lens 10' and a biconvex positive lens 11'.

[0066] The fifth lens group G5' has a negative combined optical power and is composed of three lenses, namely a double concave negative lens 12', a double concave negative lens 13' and a concave flat negative lens 14'. The sixth lens group G6' has a positive combined optical power and includes: a double convex positive lens 15', a double convex positive lens 16', an aperture stop a' and a double convex positive lens 17'. Among them, the first negative lens 14' is a concave flat negative lens, and the first positive lens 15' is a double convex positive lens. The two are closely connected to form a first close-contact double-separated lens group to achieve correction of field chromatic aberration. Furthermore, the optical power of the first negative lens 14' and the first positive lens 15' do not compensate each other, but retain a certain residual combined optical power. In terms of material selection, the Abbe constant (dispersion) of the optical material of the first negative lens 14' and the first positive lens 15' is as different as possible. Preferably, the material of the first negative lens 14' is flint glass, and the material of the first positive lens 15' is crown glass. Furthermore, the biconvex positive lens 16 ′ and the biconvex positive lens 17 ′ are symmetrically distributed about the aperture stop a′ to improve imaging quality.

[0067] The seventh lens group G7' has a negative combined optical power and is composed of a biconcave negative lens 18'. The eighth lens group G8' has a positive combined optical power and is composed of three lenses, namely a biconvex positive lens 19', a convex-concave positive lens 20' and a biconvex positive lens 21'. Among them, the second negative lens 18' is a biconcave negative lens, and the second positive lens 19' is a biconvex positive lens. The two are closely connected to form a second close-contact double-separated lens group to achieve correction of field chromatic aberration. Furthermore, the optical power of the second negative lens 18' and the second positive lens 19' do not compensate each other, but retain a certain residual combined optical power. In terms of material selection, the Abbe constant (dispersion) of the optical material of the second negative lens 18' and the second positive lens 19' is as different as possible. Preferably, the material of the second negative lens 18' is flint glass, and the material of the second positive lens 19' is crown glass. Furthermore, the first close-contact double-separated lens group and the second close-contact double-separated lens group are symmetrically distributed about the aperture stop a' to improve imaging quality.

[0068] The ninth lens group G9' has a negative combined optical power and is composed of two lenses, namely a negative meniscus lens 22' and a negative meniscus lens 23'. The tenth lens group G10 has a positive optical power and is composed of a convex-concave positive lens 24'.

[0069] Similarly, the projection lithography objective lens provided in this embodiment also includes an object plane plate 1' and an image plane plate 24'. One side of the object plane plate 1' is adjacent to the object plane, and the other side thereof is adjacent to the first lens group G1'. One side of the image plane plate 24' is adjacent to the image plane, and the other side thereof is adjacent to the tenth lens group G10'. The optical power of the object plane plate 1' and the image plane plate 24' is zero.

[0070] Furthermore, the projection lithography objective lens provided in this embodiment includes three aspheric surfaces, which are located on the front surface of the biconcave negative lens 2', the front surface of the biconcave negative lens 8', and the rear surface of the biconcave negative lens 16'. All of the aspheric surfaces are concave surfaces with good processing performance, and the aspheric surface deviation reaches the processing level of the optical industry. Therefore, not only does this reduce the total number of lenses in the entire system, lowering costs and making the entire projection lithography objective lens structure simpler and more compact, effectively controlling the incident height of the light beam on each lens and the lens size, but it also corrects chromatic aberration in the field of view, improving imaging quality.

[0071] For details not provided in this embodiment, please refer to the description in the first embodiment.

[0072] In order to verify the imaging effect of the projection lithography objective lens provided in this embodiment, the applicant Figure 7 The projection lithography objective lens shown in the figure is simulated and tested. Among them, the total length of the projection lithography objective lens is 900mm, the maximum lens semi-aperture is 101.9mm, the object side working distance of the projection objective lens is 32mm, and the image side working distance is 8mm. It is suitable for the i-line ultraviolet spectrum range, the maximum spectrum half-height full width is 2.5nm, the system magnification is β and is 1 / 5, the numerical aperture of the image side is 0.63, the image side half field height is 15.56mm, and the achievable rectangular exposure field size is: 22mmx22mm. In addition, this embodiment realizes a double telecentric structure, and the main light of each field of view on the object side is approximately parallel to the optical axis and incident on the front surface of the first parallel flat plate; the main light of each field of view on the image side is approximately parallel to the optical axis and emerges and converges on the image plane. The angles with the optical axis are: 6.5mrad on the object side and 2.4mrad on the image side.

[0073] Specific experimental parameters are shown in the table below:

[0074] Table 5 Design values ​​of Example 2

[0075]

[0076] Table 6 Design values ​​of Example 2

[0077]

[0078]

[0079] Table 7 Aspheric coefficients of Example 2

[0080] Surface serial number Aspheric Surface_4A Aspheric_16A Aspheric_38A Radius of curvature -105.639853608749 -169.027898866907 357.028384549714 K 0 0 0 A 1.54816153086151e-008 -3.59328191261703e-007 9.94968504445455e-008 B 6.3879678807006e-013 -1.53225033560877e-011 1.37689474228502e-014 C 5.88649991250641e-017 -2.36763622794357e-016 -6.34959123361593e-017 D 1.5946919205399e-023 -3.69530035897213e-019 -1.11384196802737e-021 E 6.87333129094034e-025 1.33913258773842e-022 4.10362749006097e-025 F -1.78351141929368e-029 -1.62138128647438e-026 -8.34734417873539e-030

[0081] Table 8 Refractive index of materials in Example 2

[0082] Material Refractive index@365.30nm Air 1 SFSL5Y_OHARA 1.504001 N5742_NIKON 1.612550 N5859_NIKON 1.614435 NIFSS_NIKON 1.474514 PBL6Y_OHARA 1.559515

[0083] In Table 6, a positive radius value indicates that the center of curvature is to the right of the surface, a negative radius value indicates that the center of curvature is to the left of the surface, and a radius of curvature value of 1.00E+18 indicates a flat surface. The thickness of an optical element or the spacing between two optical elements is the on-axis distance to the next surface. All dimensions are in millimeters. Table 7 shows the aspheric coefficients corresponding to the surface numbers in Table 6. For specific calculation formulas, please refer to Example 1. In this example, G = 0, H = 0, and J = 0. Table 8 shows the relative refractive index data of the optical materials used in this embodiment relative to air at a wavelength of 365.3 nm.

[0084] According to the test results: Figure 8 is the Modulation Transfer Function (MTF) curve, from Figure 8 It can be seen from the figure that the multi-color modulation transfer function is very close to the diffraction limit, which shows that the visual quality produced by the lithography projection objective lens provided by this embodiment is very good. Figure 9 is the image wavefront aberration (WFE) distribution diagram at the central reference wavelength of 365.3nm, Figure 10 is the distorted image distribution diagram, Figure 11 is the color difference curve, Figure 12 is the aberration curve. It can be seen that the lithography projection objective lens provided in this embodiment produces excellent wavefront aberration, distortion correction, chromatic aberration correction, and aberration correction effects. Therefore, based on the first embodiment, this embodiment not only achieves a large field of view and high resolution, but also reduces the use of lenses.

[0085] In summary, the first and second embodiments provide a projection lithography objective lens and a lithography machine, wherein the projection lithography objective lens includes: a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, a sixth lens group, a seventh lens group, an eighth lens group, a ninth lens group, and a tenth lens group, which are arranged in sequence along the optical path. The lenses in the first lens group include at least one aspheric surface, and the aspheric surface is arranged toward the object plane to shorten the conjugate distance of the objective lens and make the objective lens structure more compact. The fifth lens group includes a first negative lens, the sixth lens group includes a first positive lens, and the first negative lens and the first positive lens are arranged adjacent to each other to form a close-fitting double-separated lens group, which can achieve chromatic aberration correction of the field of view. The seventh lens group includes a second negative lens, the eighth lens group includes a fourth positive lens, and the second negative lens and the fourth positive lens are arranged adjacent to each other to form a close-fitting double-separated lens group, which further achieves chromatic aberration correction of the field of view and improves the imaging quality of the field of view. The lenses in the third and seventh lens groups each include at least one aspheric surface. Because aspheric surfaces increase the degree of freedom of optimization compared to spherical surfaces, one aspheric surface can in principle replace the aberration correction effect of 2-3 spherical lenses. While ensuring resolution, the number of lenses can be reduced, making the objective lens structure more compact and reducing costs.

[0086] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. In addition, the different parts between the various embodiments can also be used in combination with each other, and the present invention is not limited to this.

[0087] Furthermore, it should be recognized that although the present invention has been disclosed above with reference to preferred embodiments, the above embodiments are not intended to limit the present invention. Any person skilled in the art can utilize the above disclosed technical content to make many possible changes and modifications to the technical solution of the present invention, or modify it into equivalent embodiments with equivalent variations, without departing from the scope of the technical solution of the present invention. Therefore, any simple modifications, equivalent variations, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A projection lithography objective lens, characterized in that: include: The first lens group, the second lens group, the third lens group, the fourth lens group, the fifth lens group, the sixth lens group, the seventh lens group, the eighth lens group, the ninth lens group and the tenth lens group are sequentially arranged along the optical path; wherein, At least one lens in the first lens group is aspherical, and the aspherical surface is arranged toward the object plane; the fifth lens group includes a first negative lens, the sixth lens group includes a first positive lens, and the first negative lens and the first positive lens are arranged adjacent to each other; the seventh lens group includes a second negative lens, the eighth lens group includes a second positive lens, and the second negative lens and the second positive lens are arranged adjacent to each other; at least one lens in each of the third lens group and the seventh lens group is aspherical; and Lenses in the first lens group, the third lens group, the fifth lens group, the seventh lens group, and the ninth lens group are all negative lenses.

2. The projection lithography objective lens according to claim 1, wherein: The sixth lens group further includes a third positive lens, an aperture stop, and a fourth positive lens arranged in sequence; wherein the third positive lens and the fourth positive lens are symmetrically distributed with respect to the aperture stop.

3. The projection lithography objective lens according to claim 2, wherein: The first negative lens and the first positive lens form a first close-contact double-separated lens group, and the second negative lens and the second positive lens form a second close-contact double-separated lens group; wherein the first close-contact double-separated lens group and the second close-contact double-separated lens group are symmetrically distributed about the aperture stop.

4. The projection lithography objective lens according to claim 1, wherein: The first lens group includes at least one meniscus negative lens, and the side of the meniscus negative lens facing the object plane is aspherical.

5. The projection lithography objective lens according to claim 1, wherein: The ninth lens group includes at least one meniscus negative lens, and the curvature direction of the meniscus negative lens is toward the image plane.

6. The projection lithography objective lens according to claim 1, wherein: The lenses in the second lens group, the fourth lens group, the sixth lens group, the eighth lens group, and the tenth lens group are all positive lenses.

7. The projection lithography objective lens according to claim 1, wherein: The material of the lens in the projection lithography objective lens includes ultraviolet high-transmittance optical glass with a refractive index greater than 1.61 at the working wavelength, and ultraviolet high-transmittance optical glass with a refractive index less than 1.51 at the working wavelength.

8. The projection lithography objective lens according to claim 1, wherein: The projection lithography objective lens further includes an object plane plate and an image plane plate; wherein one side of the object plane plate is close to the object plane, and the other side thereof is close to the first lens group; one side of the image plane plate is close to the image plane, and the other side thereof is close to the tenth lens group.

9. The projection lithography objective lens according to claim 8, characterized in that: The optical power of the object plane plate and the image plane plate is zero.

10. A photolithography machine, characterized in that: The lithography machine includes the projection lithography objective lens according to any one of claims 1 to 9.

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