Large field projection objective and lithography machine

Abstract

The application provides a large field of view projection objective lens and a photoetching machine, the large field of view projection objective lens comprises a first lens group, a second lens group, a third lens group and a fourth lens group which are sequentially arranged along an optical axis from an object side. In the application, only four lens groups are used, so that the optical structure is more compact, the cost is reduced, the transmittance of the projection objective lens system is improved, and the exposure efficiency is improved. In addition, the focal length f1 of the first lens group, the focal length f2 of the second lens group, the focal length f3 of the third lens group and the focal length f4 of the fourth lens group satisfy 1.06<|f1 / f2|<1.26; 1.76<|f2 / f3|<1.90; 1.80<|f3 / f4|<2.00; 3.85<|f1 / f4|<4.25. In this way, the exposure field of view is expanded, and high resolution is also achieved.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a large field-of-view projection lens and a photolithography machine. Background Technology

[0002] Optical projection lithography is an optical exposure process that uses the principle of optical projection imaging to transfer patterns from a photomask onto a substrate (such as a silicon wafer coated with photoresist) in a distributed, repetitive, or scanning manner. Typically, the resolution of lithography can be improved by shortening the wavelength, increasing the numerical aperture, and reducing the process factor. With the continuous increase in the integration density of integrated circuit devices, higher demands are placed on the resolution of lithography lenses. Limited by the space constraints of the overall system size, the size requirements for large field-of-view projection lenses are becoming increasingly stringent, while ensuring that the exposure performance of the lens is not affected. Miniaturization, compact structure, superior performance, and reasonable cost of large field-of-view projection lenses are increasingly becoming a technological trend and a necessity.

[0003] In the existing technology, on the one hand, the number of lenses in a large field-of-view projection lens system is relatively large. However, a large number of lenses will lead to the absorption of system energy by the lenses, thereby reducing the overall transmittance of the lens. On the other hand, there are problems such as small numerical aperture and low resolution. There is a contradiction between the exposure field diameter and resolution, making it impossible to achieve high resolution under a large exposure field. Summary of the Invention

[0004] The purpose of this invention is to provide a large field-of-view projection lens and a lithography machine, so as to achieve both expanded exposure field of view and high resolution.

[0005] To achieve the above objectives, the present invention provides a large field-of-view projection lens, comprising: a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially along the optical axis starting from the object side, wherein the focal lengths of the first lens group, the second lens group, the third lens group, and the fourth lens group satisfy the following relationship:

[0006] 1.06 < |f1 / f2| < 1.26;

[0007] 1.76 < |f2 / f3| < 1.90;

[0008] 1.80 < |f3 / f4| < 2.00;

[0009] 3.85 < |f1 / f4| < 4.25;

[0010] Wherein, f1 represents the focal length of the first lens, f2 represents the focal length of the second lens, f3 represents the focal length of the third lens, and f4 represents the focal length of the fourth lens.

[0011] Optionally, in the large field-of-view projection lens, the first lens group, the second lens group, the third lens group, and the fourth lens group all have positive optical power; the first lens group, the second lens group, the third lens group, and the fourth lens group all include aspherical lenses, each of the aspherical lenses having an aspherical surface, and the sum of the number of aspherical lenses in the first lens group, the second lens group, the third lens group, and the fourth lens group is less than or equal to 11.

[0012] Optionally, in the large field-of-view projection lens, the first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis. The first lens and the second lens are aspherical lenses, and the surfaces of the first lens and the second lens near the object side are aspherical surfaces.

[0013] Optionally, in the large field-of-view projection lens, the first lens and the second lens both have negative optical power, and the third lens and the fourth lens both have positive optical power. The first lens is a biconcave negative lens, the second lens is a meniscus negative lens, the third lens is a plano-convex positive lens, and the fourth lens is a biconvex positive lens.

[0014] Optionally, in the large field-of-view projection lens, the concave surface of the second lens faces the object side, and the concave surface of the second lens is an aspherical surface.

[0015] Optionally, in the large field-of-view projection lens, the second lens group includes:

[0016] The first sub-lens group includes at least two aspherical lenses, and the surface of all aspherical lenses near the image side is an aspherical surface;

[0017] The second sub-lens group includes at least three aspherical lenses, and the surfaces of all aspherical lenses closest to the object are aspherical surfaces; wherein the first sub-lens group is closer to the object than the second sub-lens group.

[0018] Optionally, in the large field-of-view projection lens, the first sub-lens group includes a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis. The sixth lens and the seventh lens are both aspherical lenses, and the surfaces of the sixth lens and the seventh lens near the image side are aspherical surfaces.

[0019] The second sub-lens group includes an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged sequentially along the optical axis. The eighth lens, the ninth lens, and the tenth lens are all aspherical lenses, and the surfaces of the eighth lens, the ninth lens, and the tenth lens closest to the object are all aspherical surfaces.

[0020] Optionally, in the large field-of-view projection lens, the fifth, sixth, tenth, and eleventh lenses all have positive optical power, and the seventh, eighth, and ninth lenses all have negative optical power. Specifically, the fifth and eleventh lenses are both biconvex positive lenses; the sixth and tenth lenses are both meniscus positive lenses; and the seventh, eighth, and ninth lenses are all biconcave negative lenses.

[0021] Optionally, in the large field-of-view projection lens, the concave surface of the sixth lens faces the image side, and the concave surface of the sixth lens is an aspherical surface; the concave surface of the tenth lens faces the object side, and the concave surface of the tenth lens is an aspherical surface.

[0022] Optionally, in the large field-of-view projection lens, the third lens group includes a twelfth lens, a thirteenth lens, and a fourteenth lens arranged sequentially along the optical axis. The thirteenth lens is an aspherical lens, and the surface of the thirteenth lens near the image side is an aspherical surface.

[0023] Optionally, in the large field-of-view projection lens, the twelfth lens and the fourteenth lens both have positive optical power, and the thirteenth lens has negative optical power, wherein the twelfth lens and the fourteenth lens are both biconvex positive lenses, and the thirteenth lens is a biconcave negative lens.

[0024] Optionally, in the large field-of-view projection lens, the fourth lens group includes a fifteenth lens, a sixteenth lens, a seventeenth lens, and an eighteenth lens arranged sequentially along the optical axis. The fifteenth lens, the sixteenth lens, and the seventeenth lens are all aspherical lenses. The surfaces of the fifteenth lens and the sixteenth lens near the image side are aspherical surfaces, and the surface of the seventeenth lens near the object side is an aspherical surface.

[0025] Optionally, in the large field-of-view projection lens, the fifteenth lens, the sixteenth lens, and the eighteenth lens all have positive optical power, and the seventeenth lens has negative optical power. Specifically, the fifteenth lens, the sixteenth lens, and the eighteenth lens are all meniscus positive lenses, and the seventeenth lens is a biconcave negative lens.

[0026] Optionally, in the large field-of-view projection lens, the concave surfaces of the fifteenth lens and the sixteenth lens both face the image side, and the concave surfaces of the fifteenth lens and the sixteenth lens are both aspherical surfaces.

[0027] Optionally, in the large field-of-view projection lens, the large field-of-view projection lens further includes an aperture stop, which is disposed between the second lens group and the third lens group.

[0028] Optionally, in the large field-of-view projection lens, the large field-of-view projection lens further includes an object-side parallel plate and an image-side parallel plate, the object-side parallel plate being disposed on the optical axis near the object side, and the image-side parallel plate being disposed on the optical axis near the image side.

[0029] Optionally, in the large field-of-view projection lens, the effective focal length and conjugate distance of the large field-of-view projection lens satisfy the following relationship:

[0030] 0.95 < |EFL / TT| < 1.15;

[0031] Wherein, EFL represents the effective focal length of the large field-of-view projection lens, and TT represents the conjugate distance of the large field-of-view projection lens.

[0032] Optionally, in the large field-of-view projection lens, the lenses in the first lens group, the second lens group, the third lens group, and the fourth lens group are all made of fused silica.

[0033] Optionally, in the large field-of-view projection lens, the object-side working distance is greater than 32mm and the image-side working distance is greater than 12mm.

[0034] Optionally, in the large field-of-view projection lens, the object-side telecenter is less than 6 mrad and the image-side telecenter is less than 9 mrad.

[0035] Based on the same inventive concept, the present invention also provides a lithography machine, which includes the large field-of-view projection lens as described above.

[0036] In the large field-of-view projection lens and lithography machine provided by this invention, the large field-of-view projection lens includes a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially along the optical axis starting from the object side. The large field-of-view projection lens uses only four lens groups, which makes the optical structure more compact, reduces costs, and improves the transmittance of the projection lens system, thereby increasing exposure efficiency. Furthermore, the focal lengths f1 of the first lens group, f2 of the second lens group, f3 of the third lens group, and f4 of the fourth lens group satisfy 1.06 < |f1 / f2| < 1.26; 1.76 < |f2 / f3| < 1.90; 1.80 < |f3 / f4| < 2.00; 3.85 < |f1 / f4| < 4.25. This configuration achieves both expanded exposure field of view and high resolution. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the large field-of-view projection lens in Embodiment 1 of the present invention;

[0038] Figure 2 This is a schematic diagram of the modulation transfer function curves of each field of view of the large field-of-view projection lens in Embodiment 1 of the present invention;

[0039] Figure 3 This is a schematic diagram of the centroid distortion of the large field-of-view projection lens in Embodiment 1 of the present invention;

[0040] Figure 4 This is a schematic diagram of the telecentric curve of the large field-of-view projection lens in Embodiment 1 of the present invention;

[0041] Figure 5 This is a schematic diagram of the field curvature and astigmatism of the large field-of-view projection lens according to Embodiment 1 of the present invention;

[0042] Figure 6 This is a schematic diagram of the structure of the large field-of-view projection lens in Embodiment 2 of the present invention;

[0043] Figure 7 This is a schematic diagram of the modulation transfer function curves of each field of view of the large field-of-view projection lens in Embodiment 2 of the present invention;

[0044] Figure 8 This is a schematic diagram of the centroid distortion of the large field-of-view projection lens in Embodiment 2 of the present invention;

[0045] Figure 9 This is a schematic diagram of the telecentric curve of the large field-of-view projection lens in Embodiment 2 of the present invention;

[0046] Figure 10 This is a schematic diagram of the field curvature and astigmatism of the large field-of-view projection lens in Embodiment 2 of the present invention;

[0047] The reference numerals in the attached figures are explained as follows:

[0048] 1-First lens; 2-Second lens; 3-Third lens; 4-Fourth lens; 5-Fifth lens; 6-Sixth lens; 7-Seventh lens; 8-Eighth lens; 9-Ninth lens; 10-Tenth lens; 11-Eleventh lens; 12-Twelfth lens; 13-Thirteenth lens; 14-Fourteenth lens; 15-Fifteenth lens; 16-Sixteenth lens; 17-Seventeenth lens; 18-Eighteenth lens; 110-Object-side parallel plate; 120-Image-side parallel plate; G1-First lens group; G2-Second lens group; G3-Third lens group; G4-Fourth lens group. Detailed Implementation

[0049] This invention provides a large field-of-view projection lens and a lithography machine. The large field-of-view projection lens uses only four lens groups, which makes the optical structure more compact, reduces costs, and improves the transmittance of the projection lens system, thereby increasing exposure efficiency. Furthermore, by adjusting the focal lengths f1 of the first lens group, f2 of the second lens group, f3 of the third lens group, and f4 of the fourth lens group, high resolution can be achieved while simultaneously expanding the exposure field of view.

[0050] The large field-of-view projection lens and lithography machine proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0051] Example 1

[0052] Figure 1 This is a schematic diagram of the large field-of-view projection lens provided in Embodiment 1 of the invention. Figure 1 As shown, this embodiment provides a large field-of-view projection objective lens for projecting an object-side image onto an image-side image. The large field-of-view projection objective lens includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4 arranged sequentially along the optical axis starting from the object side. In this embodiment, the large field-of-view projection objective lens uses only four lens groups, reducing the number of lenses in the objective lens compared to existing technologies. This results in a more compact optical structure, lower costs, and improved transmittance of the objective lens system, thereby increasing exposure efficiency.

[0053] Preferably, the focal lengths of the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 satisfy the following relationship:

[0054] 1.06 < |f1 / f2| < 1.26;

[0055] 1.76 < |f2 / f3| < 1.90;

[0056] 1.80 < |f3 / f4| < 2.00;

[0057] 3.85 < |f1 / f4| < 4.25;

[0058] Where f1 represents the focal length of the first lens group G1, f2 represents the focal length of the second lens group G2, f3 represents the focal length of the third lens group G3, and f4 represents the focal length of the fourth lens group G4. This configuration achieves both an expanded exposure field of view and high resolution.

[0059] Furthermore, the effective focal length and conjugate distance (object-image conjugate distance) of the large field-of-view projection lens satisfy the following relationship:

[0060] 0.95 < |EFL / TT| < 1.15;

[0061] Wherein, EFL represents the effective focal length of the large field-of-view projection lens, and TT represents the conjugate distance of the large field-of-view projection lens.

[0062] In this embodiment, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 all have positive optical power. Optical power is equal to the difference between the image-side beam convergence and the object-side beam convergence; it characterizes the optical system's ability to deflect light. The larger the absolute value of the optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When the optical power is positive, the refraction of light is converging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0063] The first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 all include aspherical lenses, which are lenses with aspherical surfaces. Each aspherical lens has one aspherical surface, and the other surface of the aspherical lens is either spherical or flat. Because the manufacturing and testing difficulty of an aspherical lens with only one aspherical surface is much lower than that of an aspherical lens with two aspherical surfaces, this embodiment sets the aspherical lens to have only one aspherical surface, reducing the manufacturing and measurement costs of the aspherical lens. Furthermore, the sum of the number of aspherical lenses in the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 is less than or equal to 11. That is, the total number of aspherical lenses used in the four lens groups of the large field-of-view projection lens is less than or equal to 11, using fewer aspherical lenses, thus reducing the cost of the projection lens while ensuring image quality.

[0064] Furthermore, aspherical lenses have better aberration correction effects compared to spherical lenses. In this embodiment, each lens group in the large field-of-view projection lens includes an aspherical lens, ensuring that each lens group in the large field-of-view projection lens has a good aberration correction effect, thereby improving the imaging quality of the large field-of-view projection lens.

[0065] For example, the first lens group G1 includes four lenses arranged sequentially along the optical axis: a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4. The first lens 1 and the second lens 2 are aspherical lenses, and the surfaces of the first lens 1 and the second lens 2 closest to the object side are aspherical surfaces. Both the first lens 1 and the second lens 2 have negative optical power. The first lens 1 can be a biconcave negative lens for diverging beams. The second lens 2 can be a meniscus negative lens with a small radius of curvature, which helps eliminate chromatic aberration and corrects aberrations.

[0066] In a preferred embodiment, the concave surface of the second lens 2 faces the object, and the concave surface of the second lens 2 is aspherical. Since the detection accuracy of concave surfaces in a lens is higher than that of convex surfaces, in this embodiment of the invention, the aspherical surface is placed on the concave surface of the aspherical lens, improving the detection accuracy of the aspherical surface and thus enhancing the product reliability of the large field-of-view projection lens.

[0067] Both the third lens 3 and the fourth lens 4 have positive optical power. The third lens 3 can be a plano-convex positive lens for converging the light beam. The fourth lens 4 can be a biconvex positive lens for converging the light beam.

[0068] The second lens group G2 includes a first sub-lens group and a second sub-lens group, with the first sub-lens group being closer to the object side than the second sub-lens group. The first sub-lens group includes at least two aspherical lenses, and the surfaces of all aspherical lenses closest to the image side are aspherical surfaces.

[0069] Specifically, the first sub-lens group includes a fifth lens 5, a sixth lens 6, and a seventh lens 7 arranged sequentially along the optical axis. The fifth lens 5 has positive optical power and is a biconvex positive lens used to converge the light beam. The sixth lens 6 has positive optical power and is an aspherical lens, with the surface of the sixth lens 6 closest to the image side being an aspherical surface. The sixth lens 6 is a meniscus positive lens, which helps to eliminate chromatic aberration. Furthermore, the concave surface of the sixth lens 6 faces the image side, and the concave surface of the sixth lens 6 is an aspherical surface.

[0070] The seventh lens 7 has negative optical power, is an aspherical lens, and the surface of the seventh lens 7 near the image side is an aspherical surface. Specifically, the seventh lens 7 is a biconcave negative lens used to diverge the light beam.

[0071] The second sub-lens group includes at least three aspherical lenses, all of which have aspherical surfaces on the side closest to the object. Specifically, the second sub-lens group includes an eighth lens 8, a ninth lens 9, a tenth lens 10, and an eleventh lens 11 arranged sequentially along the optical axis.

[0072] The eighth lens 8, the ninth lens 9, and the tenth lens 10 are all aspherical lenses, and the surfaces of the eighth lens 8, the ninth lens 9, and the tenth lens 10 closest to the object are all aspherical surfaces. The eighth lens 8 and the ninth lens 9 both have negative optical power, and both can be biconcave negative lenses for diverging beams.

[0073] The tenth lens 10 has positive optical power and is a meniscus positive lens used to converge light beams. Furthermore, the concave surface of the tenth lens 10 faces the object side, and the concave surface of the tenth lens 10 is an aspherical surface.

[0074] The eleventh lens 11 has positive optical power and is a biconvex positive lens used to converge light beams. That is, the fifth lens 5, the sixth lens 6, the seventh lens 7, the ninth lens 9, the tenth lens 10, and the eleventh lens 11 in the second lens group G2 are symmetrically distributed on both sides of the eighth lens 8.

[0075] Furthermore, the large field-of-view lens objective has an optical system structure with a waist. The waist represents the position where the lens aperture contracts, thus reducing the effective aperture of the light spot passing through the corresponding lens. Specifically, the waist of the large field-of-view projection objective is located within the second lens group G2. Since the second lens group G2 includes a seventh lens 7, an eighth lens 8, and a ninth lens 9 with negative optical power, these lenses with negative optical power appear in the region of relatively small light spot aperture in the optical path of the projection objective. This allows the use of lenses with relatively small effective light-transmitting apertures in the second lens group G2, and is beneficial for correcting field curvature aberrations. In addition, the aperture of the aspherical lenses (i.e., the seventh lens 7, the eighth lens 8, and the ninth lens 9) in the second lens group G2 can be reduced, thereby reducing the manufacturing and inspection difficulty of aspherical lenses and thus reducing manufacturing costs. Here, the lens aperture refers to the effective light-transmitting aperture of the lens.

[0076] Furthermore, at least one lens in the second lens group G2 has a maximum effective half-aperture not exceeding 170mm. For example, the eighth lens 8, since its maximum effective half-aperture does not exceed 170mm, can be made from blank material with a diameter of 340mm. Blank material of this size is relatively easy to obtain and the cost is under control.

[0077] In this embodiment, the third lens group G3 includes a twelfth lens 12, a thirteenth lens 13, and a fourteenth lens 14 arranged sequentially along the optical axis. The thirteenth lens 13 is an aspherical lens, and the surface of the thirteenth lens 13 closest to the image side is an aspherical surface. Both the twelfth lens 12 and the fourteenth lens 14 have positive optical power, while the thirteenth lens 13 has negative optical power. The twelfth lens 12 and the fourteenth lens 14 are both biconvex positive lenses used to converge the light beam. The thirteenth lens 13 is a biconcave negative lens used to diverge the light beam.

[0078] The fourth lens group G4 includes a fifteenth lens 15, a sixteenth lens 16, a seventeenth lens 17, and an eighteenth lens 18 arranged sequentially along the optical axis. The fifteenth lens 15, the sixteenth lens 16, and the seventeenth lens 17 are all aspherical lenses. The surfaces of the fifteenth lens 15 and the sixteenth lens 16 near the image side are aspherical surfaces, and the surface of the seventeenth lens 17 near the object side is an aspherical surface.

[0079] The fifteenth lens 15, the sixteenth lens 16, and the eighteenth lens 18 all have positive optical power, while the seventeenth lens 17 has negative optical power. The fifteenth lens 15 and the sixteenth lens 16 are both meniscus positive lenses, which eliminate chromatic aberration. Furthermore, the concave surfaces of both the fifteenth lens 15 and the sixteenth lens 16 face the image side, and both are aspherical surfaces. The seventeenth lens 17 has negative optical power; it is a biconcave negative lens used to diverge the light beam. The eighteenth lens 18 has positive optical power; it is a meniscus positive lens, which eliminates chromatic aberration and can correct for aberrations such as field curvature or higher-order aberrations.

[0080] Continue to refer to Figure 1 As shown, in this embodiment, the large field-of-view projection lens further includes an object-side parallel plate 110 and an image-side parallel plate 120. The object-side parallel plate 110 is disposed on the optical axis near the object side (i.e., the side of the first lens group G1 near the object side), and the image-side parallel plate 120 is disposed on the optical axis near the image side (i.e., the side of the fourth lens group G4 near the image side). The object-side parallel plate 110 and the image-side parallel plate 120 have no optical power and are used to protect the internal components of the lens. For example, they can protect the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 from external contamination.

[0081] The large field-of-view projection lens also includes a stop, which is disposed between the second lens group G2 and the third lens group G3. The stop is an aperture stop. The effective light-passing diameter of the large field-of-view projection lens can be adjusted by adjusting the size of the stop; that is, the numerical aperture of the large field-of-view projection lens can be adjusted by adjusting the stop to adapt to different application scenarios. Optionally, the maximum image-side numerical aperture of the large field-of-view projection lens provided in this embodiment can be 0.57, and the numerical aperture of the large field-of-view projection lens can be continuously adjusted within the range of 0-0.57 by adjusting the size of the stop.

[0082] Continue to refer to Figure 1As shown, the large field-of-view projection lens has a dual telecentric structure on both the object and image sides. The principal rays of each field of view on the object side are incident approximately parallel to the optical axis onto the surface of the object-side parallel plate 110 near the object side (i.e., the front surface of the object-side parallel plate). On the object side, the principal rays of each field of view on the object surface are incident parallel to the optical axis onto the object-side parallel plate 110, with an angle of less than 6 mrad between the principal rays and the optical axis. On the image side, the principal rays of each field of view exit parallel to the optical axis and are imaged onto the image plane, with an angle of greater than 7 mrad between the principal rays and the optical axis. Furthermore, the principal rays of each field of view on the image side exit approximately parallel to the optical axis and converge on the image plane, which improves overlay accuracy. In addition, the object-side working distance of the large field-of-view projection lens is greater than 32 mm, and the image-side working distance is greater than 12 mm.

[0083] Table 1 provides the specific parameters of the projection lens in the first embodiment. A positive radius (R) value indicates that the center of curvature of the lens is closer to the image side; a negative radius (R) value indicates that the center of curvature of the lens is closer to the object side. In the serial numbers, "OBJ" represents the object plane, "P1" represents the object-side parallel plate, "STOP" represents the aperture stop, "P2" represents the image-side parallel plate, "IMA" represents the image plane, "a" represents the surface of the lens closer to the object side, and "b" represents the surface of the lens closer to the image side. For example, "18a" represents the surface of the eighteenth lens 18 closer to the object side. A radius of "1.00E+18" indicates that the lens surface corresponding to this radius is flat. "Full aperture" represents the maximum light-transmitting aperture of the lens surface. "Thickness" represents the thickness of the air gap or optical element.

[0084] Table 1 Parameters of large field-of-view projection lenses

[0085]

[0086]

[0087]

[0088] In this embodiment, the lenses in the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 can be made of fused silica, but are not limited to this; other materials with a refractive index of 1.45 can also be used. Furthermore, the object-side parallel plate 110 and the image-side parallel plate 120 can also be made of fused silica. Since fused silica has a refractive index of 1.45 and an Abbe number of 67, it is relatively stable, reliable, and has superior performance. Lenses made using fused silica have the advantages of stable processing and high product yield, good manufacturability, and controllable cost.

[0089] In this embodiment, the expression for the aspherical surface of the aspherical lens is:

[0090]

[0091] in, r represents the radial distance along the diagonal of x and y, x represents the coordinate value in the X direction, y represents the coordinate value in the Y direction, z represents the axial sagitta in the Z direction of the surface, the X, Y, and Z directions conform to the Cartesian coordinate system, k represents the conic coefficient of the best-fit cone, c represents the curvature of the best-fit sphere, and A, B, C, D, E, F, G, H, and J all represent aspherical coefficients (A is a fourth-order constant coefficient, B is a sixth-order constant coefficient, C is an eighth-order constant coefficient, D is a tenth-order constant coefficient, E is a twelfth-order constant coefficient, F is a fourteenth-order constant coefficient, G is a sixteenth-order constant coefficient, H is an eighteenth-order constant coefficient, and J is a twentieth-order constant coefficient).

[0092] Table 2. Specific design values ​​for the aspherical surface of the aspherical lens in the large field-of-view projection lens.

[0093]

[0094]

[0095] In this embodiment, the total length of the large field-of-view projection lens does not exceed 1300mm, it is suitable for the i-line ultraviolet spectral range, and the maximum spectral width can reach 5nm. For example, the reference wavelength can be 355nm, the spectral width can be 0.001nm or -0.001nm, the magnification can be -0.5, the maximum numerical aperture on the image side can be 0.57, the diameter of the image side field of view (exposure field of view) is not less than 65.0mm, and the maximum height of the field of view can be 32.5mm.

[0096] Figure 2 This is a schematic diagram of the modulation transfer function curves of each field of view of the large field-of-view projection lens in Embodiment 1 of the present invention. Figure 2 In the diagram, the horizontal axis represents spatial frequency, measured in line pairs per millimeter (lp / mm), and the vertical axis represents modulation degree (or contrast ratio). The modulation transfer function (MTF) is a function of spatial frequency, reflecting the optical system's ability to transmit sinusoidal modulation at various frequencies. For example... Figure 2 As shown, the performance of the large field-of-view projection lens is close to the diffraction limit, and its performance is excellent throughout the entire field of view.

[0097] Figure 3 This is a centroid distortion diagram of the large field-of-view projection lens in Embodiment 1 of the present invention. Figure 3 In the graph, the horizontal axis represents the X object height, indicating the height of the object field of view in the X direction, with the unit being mm. The vertical axis represents the Y object height, indicating the height of the object field of view in the Y direction, with the unit being mm. Figure 3 It can be seen that the distortion at each object half-field point is basically 0, that is, the distortion of the large field-of-view projection lens has been corrected to 0.

[0098] Figure 4 This is a telecentric curve diagram of the large field-of-view projection lens of Embodiment 1 of the present invention, wherein, Figure 4 The x-axis represents the object height, and the y-axis represents the telecentricity. Figure 4 As can be seen from curve a in the figure, the object-side telecenter (TE object) of the large field-of-view projection lens is less than 6 mrad. Figure 4 As can be seen from curve b, the image-side telecentric (TE image) of the large field-of-view projection lens is less than 7 mrad. Figure 5 This is a schematic diagram of the field curvature and astigmatism of the large field-of-view projection lens according to Embodiment 1 of the present invention. Figure 5 It can be seen that the field curvature and astigmatism of the large field-of-view projection lens have been corrected to a smaller range.

[0099] Based on the same inventive concept, this embodiment also provides a lithography machine, which includes the large field-of-view projection lens as described above, and will not be repeated here.

[0100]

Example 2

[0101] Figure 6 This is a structural diagram of the large field-of-view projection lens provided in Embodiment 2 of the present invention. Figure 6 As shown, this embodiment provides a large field-of-view projection lens for projecting an object-side image onto an image-side image. The large field-of-view projection lens includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4 arranged sequentially along the optical axis starting from the object side. In this embodiment, the focal lengths of the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 satisfy the following relationships: 1.06 < |f1 / f2| < 1.26; 1.76 < |f2 / f3| < 1.90; 1.80 < |f3 / f4| < 2.00; 3.85 < |f1 / f4| < 4.25; where f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, f3 represents the focal length of the third lens group, and f4 represents the focal length of the fourth lens group.

[0102] The structure of the large field-of-view projection lens in this embodiment is the same as that in Embodiment 1, and will not be repeated here. The difference between this embodiment and Embodiment 1 lies in the operating conditions, exposure field of view size, and image-side numerical aperture of the large field-of-view projection lens in this embodiment. Specifically, in this embodiment, the large field-of-view projection lens can be used in the i-line ultraviolet spectral range with a wavelength of 355 nm, a spectral width of 0.001 nm or -0.001 nm, a magnification of -0.5, an image-side maximum numerical aperture of 0.45, and an image-side field of view (exposure field of view) of 54.0 mm x 34.0 mm to improve exposure efficiency.

[0103] Figure 7 This is a schematic diagram of the modulation transfer function curves for each field of view of the large field-of-view projection lens in Example 2. Figure 7 In the graph, the horizontal axis represents spatial frequency, measured in line pairs per millimeter (lp / mm), and the vertical axis represents modulation depth (or contrast ratio). The modulation transfer function (MTF) is a function of spatial frequency, reflecting the optical system's ability to transmit sinusoidal modulation at various frequencies. Figure 7 It can be seen that the performance of the large field-of-view projection lens is close to the diffraction limit, and its performance is excellent throughout the entire field of view. Figure 8 This is a centroid distortion diagram of the large field-of-view projection lens in Embodiment 2 of the present invention. The horizontal axis represents the X-object height, indicating the height of the object-side field of view in the X direction, with units in mm. The vertical axis represents the Y-object height, indicating the height of the object-side field of view in the Y direction, with units in mm. Figure 8 It can be seen that the distortion at each object half-field point is basically 0, indicating that the objective lens distortion has been corrected to 0. Figure 9 This is a schematic diagram of the telecentric curve of the large field-of-view projection lens in Embodiment 2 of the present invention. Figure 9 As can be seen from curve c, the object-side telecenter (TE object) of the large field-of-view projection lens is less than 6 mrad. Figure 9 As can be seen from curve d, the image-side telecenter (TEimage) of the large field-of-view projection lens is less than 7 mrad. Figure 10 This is a schematic diagram of the field curvature and astigmatism of the large field-of-view projection lens in Example 2, by... Figure 10 It can be seen that the field curvature and astigmatism of the large field-of-view projection lens have been corrected to a smaller range.

[0104] Based on the same inventive concept, this invention also provides a lithography machine, which includes the large field-of-view projection lens as described above, and will not be repeated here.

[0105] In summary, the large field-of-view projection lens and lithography machine provided in this embodiment of the invention include a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially along the optical axis from the object side. The large field-of-view projection lens uses only four lens groups, which makes the optical structure more compact, reduces costs, and improves the transmittance of the projection lens system, thereby increasing exposure efficiency. Furthermore, the focal lengths f1 of the first lens group, f2 of the second lens group, f3 of the third lens group, and f4 of the fourth lens group satisfy 1.06 < |f1 / f2| < 1.26; 1.76 < |f2 / f3| < 1.90; 1.80 < |f3 / f4| < 2.00; 3.85 < |f1 / f4| < 4.25. This configuration achieves both expanded exposure field of view and high resolution.

[0106] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A large field of view projection objective for projecting an object side image on an image side, characterized in that The lens comprises, in order from the object side along the optical axis, a first lens group, a second lens group, a third lens group and a fourth lens group, the first lens group, the second lens group, the third lens group and the fourth lens group all have positive focal power, the first lens group, the second lens group, the third lens group and the fourth lens group all comprise aspherical lenses, each of the aspherical lenses has an aspherical surface, the sum of the number of the aspherical lenses in the first lens group, the second lens group, the third lens group and the fourth lens group is less than or equal to 11, wherein the focal length of the first lens group, the focal length of the second lens group, the focal length of the third lens group and the focal length of the fourth lens group satisfy the following relationships: 1.06<|f1 / f2|<1.26; 1.76<|f2 / f3|<1.90; 1.80<|f3 / f4|<2.00; 3.85<|f1 / f4|<4.25; Wherein, f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, f3 represents the focal length of the third lens group, and f4 represents the focal length of the fourth lens group.

2. The large field projection objective according to claim 1, characterized in that The first lens group comprises, in order along the optical axis, a first lens, a second lens, a third lens and a fourth lens, the first lens and the second lens are aspherical lenses, and the surfaces of the first lens and the second lens close to the object side are aspherical surfaces.

3. The large field projection objective according to claim 2, characterized in that The first lens and the second lens both have negative focal power, the third lens and the fourth lens both have positive focal power, wherein the first lens is a double-concave negative lens, the second lens is a meniscus negative lens, the third lens is a flat-convex positive lens, and the fourth lens is a double-convex positive lens.

4. The large field projection objective according to claim 3, characterized in that The concave surface of the second lens faces the object side, and the concave surface of the second lens is an aspherical surface.

5. The large field of view projection objective according to claim 1, characterized in that The second lens group comprises: A first sub-lens group comprising at least two aspherical lenses, the surfaces of all the aspherical lenses close to the image side are aspherical surfaces; A second sub-lens group comprising at least three aspherical lenses, the surfaces of all the aspherical lenses close to the object side are aspherical surfaces; Wherein, the first sub-lens group is closer to the object side than the second sub-lens group.

6. The large field projection objective according to claim 5, characterized in that The first sub-lens group comprises, in order along the optical axis, a fifth lens, a sixth lens and a seventh lens, the sixth lens and the seventh lens are aspherical lenses, and the surfaces of the sixth lens and the seventh lens close to the image side are aspherical surfaces; The second sub-lens group comprises, in order along the optical axis, an eighth lens, a ninth lens, a tenth lens and an eleventh lens, the eighth lens, the ninth lens and the tenth lens are aspherical lenses, and the surfaces of the eighth lens, the ninth lens and the tenth lens close to the object side are aspherical surfaces.

7. The large field projection objective according to claim 6, characterized in that The fifth lens, the sixth lens, the tenth lens and the eleventh lens all have positive focal powers, the seventh lens, the eighth lens and the ninth lens all have negative focal powers, wherein the fifth lens and the eleventh lens are both double-convex positive lenses; the sixth lens and the tenth lens are both meniscus positive lenses; the seventh lens, the eighth lens and the ninth lens are all double-concave negative lenses.

8. The large field projection objective according to claim 7, characterized in that The concave surface of the sixth lens faces the image side, and the concave surface of the sixth lens is a non-spherical surface; the concave surface of the tenth lens faces the object side, and the concave surface of the tenth lens is a non-spherical surface.

9. The projection objective of claim 1, characterized in that The third lens group comprises a twelfth lens, a thirteenth lens and a fourteenth lens arranged in sequence along the optical axis, the thirteenth lens is a non-spherical lens, and the surface of the thirteenth lens close to the image side is a non-spherical surface.

10. The large field projection objective according to claim 9, characterized in that The twelfth lens and the fourteenth lens both have positive focal powers, and the thirteenth lens has a negative focal power, wherein the twelfth lens and the fourteenth lens are both double-convex positive lenses, and the thirteenth lens is a double-concave negative lens.

11. The projection objective of claim 1, characterized in that The fourth lens group comprises a fifteenth lens, a sixteenth lens, a seventeenth lens and an eighteenth lens arranged in sequence along the optical axis, the fifteenth lens, the sixteenth lens and the seventeenth lens are all non-spherical lenses, the surfaces of the fifteenth lens and the sixteenth lens close to the image side are non-spherical surfaces, and the surface of the seventeenth lens close to the object side is a non-spherical surface.

12. The large field projection objective according to claim 11, characterized in that The fifteenth lens, the sixteenth lens and the eighteenth lens all have positive focal powers, and the seventeenth lens has a negative focal power, wherein the fifteenth lens, the sixteenth lens and the eighteenth lens are all meniscus positive lenses, and the seventeenth lens is a double-concave negative lens.

13. The large field projection objective according to claim 12, characterized in that The concave surface of the fifteenth lens and the concave surface of the sixteenth lens both face the image side, and the concave surface of the fifteenth lens and the concave surface of the sixteenth lens are both non-spherical surfaces.

14. The projection objective of any one of claims 1 to 13, characterized in that The large-view-field projection objective lens further comprises a diaphragm, which is arranged between the second lens group and the third lens group.

15. The projection objective of any one of claims 1 to 13, characterized in that The large-view-field projection objective lens further comprises an object-side parallel flat plate and an image-side parallel flat plate, the object-side parallel flat plate is arranged on the side of the optical axis close to the object side, and the image-side parallel flat plate is arranged on the side of the optical axis close to the image side.

16. The projection objective of any one of claims 1 to 13, characterized in that The effective focal length and the conjugate distance of the large-view-field projection objective lens satisfy the following relationship: 0.95<| EFL / TT|<1.15; wherein EFL represents the effective focal length of the large-view-field projection objective lens, and TT represents the conjugate distance of the large-view-field projection objective lens.

17. The projection objective of any one of claims 1 to 13, characterized in that The materials of the lenses in the first lens group, the second lens group, the third lens group and the fourth lens group are all fused quartz.

18. The projection objective of any one of claims 1 to 13, characterized in that The object-side working distance of the large-view-field projection objective lens is greater than 32 mm, and the image-side working distance is greater than 12 mm.

19. The projection objective of any one of claims 1 to 13, characterized in that The object-side telecentricity of the large-view-field projection objective lens is less than 6 mrad, and the image-side telecentricity is less than 7 mrad.

20. A lithographic machine characterized by, The photolithography machine comprises the large-view-field projection objective lens according to any one of claims 1 to 19.

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