Objective lens module and photoetching imaging system

Abstract

The invention provides an objective lens module and a photoetching imaging system, and relates to the technical field of optical imaging, the objective lens module is configured between an object plane and an image plane of the photoetching imaging system, and the objective lens module comprises a first lens group, a second lens group and a microobjective lens group which are sequentially arranged from the object plane to the image plane, the first lens group and the second lens group are both of a double-Gaussian structure or a double-Gaussian derivative structure, and the focal length of the first lens group is larger than that of the second lens group. The objective lens module can reduce the aperture size of the optical lens in the objective lens module, increase the object space working distance and improve the imaging quality on the premise of ensuring a large field of view.

Description

Technical Field

[0001] The present application relates to the field of optical imaging technology, and in particular to an objective lens module and a photolithography imaging system. Background Art

[0002] The lithography machine is a core device that efficiently replicates tiny and precise integrated circuits on silicon wafers through the photolithography process. The exposure field of view, resolution and working stability of the lithography imaging system of the lithography machine directly determine the chip manufacturing capability.

[0003] The objective lens module in the photolithography imaging system usually needs to provide the largest possible field of view within a limited spatial size. The objective lens module has a large number of optical lenses, which often leads to complex structure and large aperture of the objective lens module. This further makes the processing, manufacturing, assembly and debugging of the objective lens module more difficult. The reduced yield caused by the manufacturing difficulties also increases the manufacturing cost. Summary of the invention

[0004] The present application provides an objective lens module and a photolithography imaging system. The objective lens module of the present application can reduce the aperture size of the optical lens in the objective lens module, increase the object working distance, and improve the imaging quality while ensuring a larger field of view.

[0005] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows: In one aspect of an embodiment of the present application, an objective lens module is provided, which is arranged between an object plane and an image plane of a lithography imaging system. The objective lens module includes a first lens group, a second lens group, and a microscope objective lens group, which are arranged in sequence from the object plane to the image plane. The first lens group and the second lens group are both double Gaussian structures or both are double Gaussian derivative structures. The focal length of the first lens group is greater than the focal length of the second lens group.

[0006] In some feasible implementations, the optical power p1 of the first lens group, the optical power p2 of the second lens group, and the optical power p3 of the microscope objective lens group satisfy the following relationship: 0<|p1|<1 / 5000; 1 / 1000<|p2|<1 / 400; 1 / 200<|p3|<1 / 100; 3<|p3 / p2|<7; where the focal length is in millimeters.

[0007] In some feasible embodiments, the first lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along the main optical axis, the optical focal power of the first lens and the optical focal power of the second lens are positive optical focal powers, the optical focal powers of the third lens, the fourth lens and the fifth lens are negative optical focal powers, and the optical focal powers of the sixth lens and the seventh lens are positive optical focal powers.

[0008] In some feasible embodiments, the second lens is a plano-convex lens, the third lens is a plano-concave lens, the fourth lens and the fifth lens are biconcave lenses, and the sixth lens and the seventh lens are meniscus positive lenses.

[0009] In some feasible embodiments, the focal length f1 of the first lens and the refractive index n1 of the first lens satisfy: 300 mm < f1 < 400 mm; n1 = 1.58; the focal length f2 of the second lens and the refractive index n2 of the second lens satisfy: 200 mm < f2 < 300 mm; n2 = 1.52; the focal length f3 of the third lens and the refractive index n3 of the third lens satisfy: -200 mm < f3 < -100 mm; n3 = 1.60; the focal length f4 of the fourth lens and the refractive index n4 of the fourth lens satisfy: -200 mm < f4 < -100 mm; n4 = 1.59; the focal length f5 of the fifth lens and the refractive index n5 of the fifth lens satisfy: -200 mm < f5 < -100 mm; n5 = 1.60; the focal length f6 of the sixth lens and the refractive index n6 of the sixth lens satisfy: 900 mm < f6 < 1000 mm; n6 = 1.59; the focal length f7 of the seventh lens and the refractive index n7 of the seventh lens satisfy: 380 mm < f7 < 480 mm; n7 = 1.50.

[0010] In some feasible embodiments, the second lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, and a fifteenth lens arranged in sequence along the principal optical axis. The optical power of the eighth lens, the optical power of the ninth lens, and the optical power of the tenth lens are positive optical powers. The optical power of the eleventh lens, the optical power of the twelfth lens, and the optical power of the thirteenth lens are negative optical powers. The optical power of the fourteenth lens and the optical power of the fifteenth lens are positive optical powers.

[0011] In some feasible embodiments, the eighth lens and the ninth lens are meniscus positive lenses, the tenth lens is a biconvex lens, the eleventh lens and the twelfth lens are biconcave lenses, the thirteenth lens is a meniscus negative lens, and the fourteenth lens and the fifteenth lens are biconvex lenses.

[0012] In some feasible embodiments, the focal length f8 and refractive index n8 of the eighth lens satisfy: 2000 mm < f8 < 2600 mm; n8 = 1.62; the focal length f9 and refractive index n9 of the ninth lens satisfy: 7000 mm < f9 < ∞; n9 = 1.60; the focal length f10 and refractive index n10 of the tenth lens satisfy: 200 mm < f10 < 300 mm; n10 = 1.60; the focal length f11 and refractive index n11 of the eleventh lens satisfy: -200 mm < f11 < -150 mm; n11 = 1.60; the focal length f12 and refractive index n12 of the twelfth lens satisfy: -300 mm < f12 < -200 mm; n12 = 1.57; the focal length f13 and refractive index n13 of the thirteenth lens satisfy: -700 mm < f13 < -600 mm; n13 = 1.49; the focal length f14 and refractive index n14 of the fourteenth lens satisfy: 300 mm < f14 < 400 mm; n14 = 1.50; the focal length f15 and refractive index n15 of the fifteenth lens satisfy: 380 mm < f15 < 480 mm; n15 = 1.50.

[0013] In some feasible embodiments, the microscopic objective lens group includes a sixteenth lens, a seventeenth lens, an eighteenth lens, a nineteenth lens, a twentieth lens, a twenty - first lens, and a twenty - second lens arranged in sequence along the principal optical axis. The optical power of the sixteenth lens is positive, the optical power of the seventeenth lens is negative, and the optical powers of the eighteenth lens, the nineteenth lens, the twentieth lens, the twenty - first lens, and the twenty - second lens are positive.

[0014] In some feasible embodiments, the sixteenth lens is a biconvex lens, the seventeenth lens is a biconcave lens, the eighteenth lens and the nineteenth lens are biconvex lenses, the twentieth lens and the twenty - first lens are meniscus positive lenses, and the twenty - second lens is a plano - convex lens.

[0015] In some feasible embodiments, the focal length f16 of the sixteenth lens and the refractive index n16 of the sixteenth lens satisfy: 300 mm < f16 < 360 mm; n16 = 1.50; the focal length f17 of the seventeenth lens and the refractive index n17 of the seventeenth lens satisfy: -250 mm < f17 < -150 mm; n17 = 1.58; the focal length f18 of the eighteenth lens and the refractive index n18 of the eighteenth lens satisfy: 400 mm < f18 < 500 mm; n18 = 1.50; the focal length f19 of the nineteenth lens and the refractive index n19 of the nineteenth lens satisfy: 400 mm < f19 < 500 mm; n19 = 1.50; the focal length f20 of the twentieth lens and the refractive index n20 of the twentieth lens satisfy: 550 mm < f20 < 650 mm; n20 = 1.49; the focal length f21 of the twenty-first lens and the refractive index n21 of the twenty-first lens satisfy: 500 mm < f21 < 600 mm; n21 = 1.62; the focal length f22 of the twenty-second lens and the refractive index n22 of the twenty-second lens satisfy: 500 mm < f22 < 600 mm; n22 = 1.57.

[0016] In some feasible embodiments, a first aspherical surface is further disposed on the light incident side surface of the first lens, and a second aspherical surface is further disposed on the light incident side surface of the eleventh lens.

[0017] On the other hand, an embodiment of the present application provides a lithographic imaging system, including the objective lens module of any one of the foregoing.

[0018] The beneficial effects of the embodiments of the present application include: The embodiments of the present application provide an objective lens module, which is disposed between the object surface and the image surface of a lithographic imaging system. The objective lens module includes a first lens group, a second lens group, and a microscopic objective lens group sequentially arranged from the object surface to the image surface. Both the first lens group and the second lens group are of a double-Gauss structure or a double-Gauss derivative structure, and the focal length of the first lens group is greater than that of the second lens group. The first lens group and the second lens group of the double-Gauss structure or the double-Gauss derivative structure can effectively correct the asymmetric aberrations in the optical path system. The focal length of the first lens group is greater than that of the second lens group. Through the mutual cooperation of the first lens group and the second lens group, the astigmatism of the system can be eliminated. When combined with the microscopic objective lens group, the design freedom of the system can be effectively optimized and improved, the object-side working distance can be increased, and the spherical aberration, coma, distortion and other optical aberrations of the system can be offset. Therefore, when the objective lens module provided by the embodiments of the present application is applied to a lithographic imaging system, on the premise of ensuring a large field of view and a large numerical aperture, the aperture of the optical elements of the objective lens module can be reduced, and a better imaging effect of the objective lens module can be ensured. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 One of the optical path schematic diagrams of an objective lens module provided in an embodiment of the present application; Figure 2 A schematic diagram of the optical path of a first lens group in an objective lens module provided in an embodiment of the present application; Figure 3 A schematic diagram of the Seidel coefficient of the first lens group in an objective lens module provided in an embodiment of the present application; Figure 4 A schematic diagram of the optical path of the second lens group in an objective lens module provided in an embodiment of the present application; Figure 5 A schematic diagram of the Seidel coefficient of the second lens group in an objective lens module provided in an embodiment of the present application; Figure 6 A schematic diagram of the optical path of a microscope objective lens group in an objective lens module provided in an embodiment of the present application; Figure 7 A schematic diagram of the Seidel coefficient of a microscope objective lens group in an objective lens module provided in an embodiment of the present application; Figure 8 A second optical path schematic diagram of an objective lens module provided in an embodiment of the present application; Fig. 9 A telecentricity curve diagram of an objective lens module provided in an embodiment of the present application; Fig.10 A wavefront error curve diagram of an output image of an objective lens module provided in an embodiment of the present application; Fig.11 A Strehl ratio curve diagram of an output image of an objective lens module provided in an embodiment of the present application; Fig.12 A field curvature curve diagram of an output image of an objective lens module provided in an embodiment of the present application; Fig.13 A distortion curve diagram of an output image of an objective lens module provided in an embodiment of the present application.

[0021] Icon: AA-first lens group; BB-second lens group; CC-microscope objective lens group; 101-first lens; 102-second lens; 103-third lens; 104-fourth lens; 105-fifth lens; 106-sixth lens; 107-seventh lens; 108-eighth lens; 109-ninth lens; 110-tenth lens; 111-eleventh lens; 112-twelfth lens; 113-thirteenth lens; 114-fourteenth lens; 115-fifteenth lens; 116-sixteenth lens; 117-seventeenth lens; 118-eighteenth lens; 119-nineteenth lens; 120-twentieth lens; 121-twenty-first lens; 122-twenty-second lens; 200-first aspheric surface; 300-second aspheric surface. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. It should be noted that, in the absence of conflict, the various features in the embodiments of the present application can be combined with each other, and the combined embodiments are still within the scope of protection of the present application.

[0023] In the description of the present application, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0024] In one aspect of an embodiment of the present application, an objective lens module is provided, which is arranged between an object plane and an image plane of a lithography imaging system. Figure 1 As shown, the objective lens module includes a first lens group AA, a second lens group BB and a microscope objective lens group CC which are arranged in sequence from the object plane to the image plane. The first lens group AA and the second lens group BB are both double Gaussian structures or double Gaussian derivative structures, and the focal length of the first lens group is greater than the focal length of the second lens group.

[0025] like Figure 1As shown, in the objective lens module provided in the embodiment of the present application, along the main light path from the object plane to the image plane, the first lens group AA and the second lens group BB are arranged before the microscope objective lens group CC, wherein the first lens group AA and the second lens group BB are both double Gaussian structures or double Gaussian derivative structures. Double Gaussian structure and its derivative structures are important concepts in optical lens design, and are usually applied to optical design in the field related to camera lenses. The basic structure of the double Gaussian structure includes two groups of symmetrical lens groups, wherein each lens group includes at least two lenses, for example, a nearly symmetrical layout combination formed by four positive-negative-negative-positive lenses is used as a double Gaussian structure. The symmetric design of the lenses in the double Gaussian structure lens group can effectively offset aberrations such as distortion and lateral chromatic aberration in the light path, achieve a certain degree of aberration correction, and is suitable for large aperture systems, with better performance. The double Gaussian derivative structure refers to further increasing the number of symmetrical lenses on the basis of the double Gaussian structure to improve edge image quality and perform chromatic aberration control, and may be partially presented as an asymmetric design.

[0026] On this basis, in the solution of the present application, the first lens group AA and the second lens group BB of the double Gaussian structure or the double Gaussian derivative structure are arranged in coordination with each other, and the focal length of the first lens group is greater than the focal length of the second lens group, so that the optical elements of the objective lens module of the embodiment of the present application can achieve a larger field of view and a larger numerical aperture with a smaller aperture, have a larger object working distance, and ensure a better imaging effect of the objective lens module.

[0027] The embodiment of the present application provides an objective lens module, which is arranged between the object plane and the image plane of the lithography imaging system. The objective lens module includes a first lens group AA, a second lens group BB and a microscope objective lens group CC, which are arranged in sequence from the object plane to the image plane. The first lens group AA and the second lens group BB are both double Gaussian structures or double Gaussian derivative structures, and the focal length of the first lens group is greater than the focal length of the second lens group. The first lens group AA and the second lens group BB of the double Gaussian structure or the double Gaussian derivative structure can effectively correct the asymmetric aberration in the optical path system, the focal length of the first lens group is greater than the focal length of the second lens group, and the mutual cooperation of the first lens group AA and the second lens group BB can eliminate the system astigmatism, and then cooperate with the microscope objective lens group CC, which can effectively optimize and improve the design freedom of the system, increase the object side working distance, and offset the optical aberrations such as spherical aberration, coma, and distortion of the system, so that the objective lens module provided by the embodiment of the present application is applied to the lithography imaging system, and the optical element aperture of the objective lens module is reduced under the premise of ensuring a larger field of view and a larger numerical aperture, and the better imaging effect of the objective lens module is ensured.

[0028] In some feasible implementations, the optical power p1 of the first lens group, the optical power p2 of the second lens group, and the optical power p3 of the microscope objective lens group satisfy the following relationship: 0<|p1|<1 / 5000; 1 / 1000<|p2|<1 / 400; 1 / 200<|p3|<1 / 100; 3<|p3 / p2|<7; where the focal length is in millimeters.

[0029] Still refer to Figure 1 As shown, the first lens group AA is composed of a plurality of different optical lenses. The optical power p1 of the first lens group refers to the comprehensive modulation (convergence or divergence) ability and imaging characteristics of the multiple optical lenses constituting the first lens group AA after the coordinated design of the multiple optical lenses constituting the first lens group AA, and is the equivalent optical power after the multiple optical lenses constituting the first lens group AA are combined. The absolute value of the optical power is expressed in inverse proportion to the focal length. In the present application scheme, the absolute values ​​of the optical power p1 of the first lens group, the optical power p2 of the second lens group, and the optical power p3 of the microscope objective lens group meet the corresponding numerical range limitation requirements, where the unit of the focal length is millimeter. In addition, the absolute value of the ratio between the optical power p3 of the microscope objective lens group and the optical power p2 of the second lens group is between 3 and 7.

[0030] The objective lens module that meets the above design can achieve an overall reduction in the optical aperture of the entire objective lens module by designing and combining the optical powers of the first lens group AA, the second lens group BB and the microscope objective lens group CC. In particular, the absolute value of the ratio between the optical power p3 of the microscope objective lens group and the optical power p2 of the second lens group is between 3 and 7, which enables the aperture stop set in front of the microscope objective lens group CC to meet the smaller aperture design.

[0031] It should be noted that the aperture diaphragm is an optical element that determines the numerical aperture of each field of view in the optical module, and the specific setting position of the aperture diaphragm in the optical module largely determines the optical performance of the optical system. For optical lenses with large fields of view and large numerical apertures, including the objective lens module of the embodiment of the present application, in order to ensure the telecentricity of the image side, it is usually selected to set the aperture diaphragm at the optical lens with the largest aperture close to the image side in the objective lens module. Moreover, when the aperture diaphragm adopts a variable diaphragm, the system numerical aperture of the objective lens module can be changed by changing the diaphragm diameter of the variable diaphragm so as to achieve imaging exposure effects of different requirements.

[0032] In the design and manufacture of the variable iris, the larger the maximum aperture of the variable iris, the higher the manufacturing difficulty. Since the design of the variable iris needs to be coordinated with the parameters of other optical elements in the optical path system, in order to reduce the maximum aperture of the variable iris without affecting the imaging exposure effect, it is necessary to coordinate with the parameters of other optical elements in the objective lens module, and focus on the ratio relationship between the focal power p3 of the microscope objective lens group and the focal power p2 of the second lens group. In the objective lens module of the embodiment of the present application, through the coordination design between the various parameters of the above-mentioned optical elements, the design of the variable iris with a smaller aperture can meet the requirements of the optical system, so that the design difficulty of the variable iris is effectively reduced, and the design and manufacturing cost of the variable iris is reduced, thereby reducing the processing cost of the entire objective lens module.

[0033] In some possible implementations, such as Figure 2 As shown, the first lens group AA includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106 and a seventh lens 107 which are sequentially arranged along the main optical axis. The focal power of the first lens and the second lens is positive, the focal power of the third lens, the fourth lens and the fifth lens is negative, and the focal power of the sixth lens and the seventh lens is positive.

[0034] In some feasible implementations, the second lens 102 is a plano-convex lens, the third lens 103 is a plano-concave lens, the fourth lens 104 and the fifth lens 105 are biconcave lenses, and the sixth lens 106 and the seventh lens 107 are positive meniscus lenses.

[0035] The incident light beam is emitted after passing through the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 105, the sixth lens 106 and the seventh lens 107 of the first lens group AA, which are the combination of the above positive and negative power. The emitted light beam is adjusted by the seven lenses of the double Gaussian structure or the double Gaussian diffraction structure in the first lens group AA, and the asymmetric aberration in the light beam is preliminarily corrected.

[0036] In some possible implementations: The focal length f1 of the first lens and the refractive index n1 of the first lens satisfy: 300mm <f1<400mm;n1=1.58; The focal length f2 of the second lens and the refractive index n2 of the second lens satisfy: 200mm <f2<300mm;n2=1.52; The focal length f3 of the third lens and the refractive index n3 of the third lens satisfy: -200mm <f3<-100mm;n3=1.60; The focal length f4 of the fourth lens and the refractive index n4 of the fourth lens satisfy: -200mm <f4<-100mm;n4=1.59; The focal length f5 of the fifth lens and the refractive index n5 of the fifth lens satisfy: -200mm <f5<-100mm;n5=1.60; The focal length f6 of the sixth lens and the refractive index n6 of the sixth lens satisfy: 900 mm <f6<1000mm;n6=1.59; The focal length f7 of the seventh lens and the refractive index n7 of the seventh lens satisfy: 380mm <f7<480mm;n7=1.50。

[0037] like Figure 3 As shown, a schematic diagram of the Seidel coefficient of the first mirror group AA is shown. Figure 3 In the figure, the horizontal axis represents aberrations, and from left to right, the colors represent spherical aberration, coma, astigmatism, field curvature and distortion. After the first lens group AA is set and designed according to the specific surface shapes and parameters of the first lens 101 to the seventh lens 107, the astigmatism is corrected due to the symmetry of the multiple optical lenses in the first lens group AA. Figure 3 It can be seen that the light beam emitted by the first lens group AA exhibits a smaller astigmatism.

[0038] In some possible implementations, such as Figure 4 As shown, the second lens group BB includes an eighth lens 108, a ninth lens 109, a tenth lens 110, an eleventh lens 111, a twelfth lens 112, a thirteenth lens 113, a fourteenth lens 114 and a fifteenth lens 115 which are sequentially arranged along the principal optical axis. The focal powers of the eighth lens, the ninth lens and the tenth lens are positive, the focal powers of the eleventh lens, the twelfth lens and the thirteenth lens are negative, and the focal powers of the fourteenth lens and the fifteenth lens are positive.

[0039] In some feasible implementations, the eighth lens 108 and the ninth lens 109 are positive meniscus lenses, the tenth lens 110 is a double convex lens, the eleventh lens 111 and the twelfth lens 112 are double concave lenses, the thirteenth lens 113 is a negative meniscus lens, and the fourteenth lens 114 and the fifteenth lens 115 are double convex lenses.

[0040] The light beam with a preliminarily corrected asymmetric phase difference by the first lens group AA enters the second lens group BB, and the light beam sequentially passes through the eighth lens 108 and the ninth lens 109 of the positive meniscus lens, the tenth lens 110 of the double convex lens, the eleventh lens 111 and the twelfth lens 112 of the double concave lens, the thirteenth lens 113 of the negative meniscus lens, the fourteenth lens 114 and the fifteenth lens 115 of the double convex lens, and then emerges. The emergent light beam is adjusted again by the double Gaussian structure or the double Gaussian diffraction structure of the second lens group BB to further correct the asymmetric aberration in the light beam.

[0041] In some possible implementations: The focal length f8 of the eighth lens and the refractive index n8 of the eighth lens satisfy: 2000mm <f8<2600mm;n8=1.62; The focal length f9 of the ninth lens and the refractive index n9 of the ninth lens satisfy: 7000mm <f9<∞;n9=1.60; The focal length f10 of the tenth lens and the refractive index n10 of the tenth lens satisfy: 200mm <f10<300mm;n10=1.60; The focal length f11 of the eleventh lens and the refractive index n11 of the eleventh lens satisfy: -200mm <f11<-150mm;n11=1.60; The focal length f12 of the twelfth lens and the refractive index n12 of the twelfth lens satisfy: -300mm <f12<-200mm;n12=1.57; The focal length f13 of the thirteenth lens and the refractive index n13 of the thirteenth lens satisfy: -700mm <f13<-600mm;n13=1.49; The focal length f14 of the fourteenth lens and the refractive index n14 of the fourteenth lens satisfy: 300 mm <f14<400mm;n14=1.50; The focal length f15 of the fifteenth lens and the refractive index n15 of the fifteenth lens satisfy: 380mm <f15<480mm;n15=1.50。

[0042] like Figure 5 As shown, a schematic diagram of the Seidel coefficient of the second lens group BB is shown. After the second lens group BB is set and designed according to the specific surface shapes and parameters of the eighth lens 108 to the fifteenth lens 115, the astigmatism is corrected due to the symmetry of the optical lenses in the second lens group BB. Figure 5 It can be seen that the light beam emitted by the second lens group BB exhibits a smaller astigmatism.

[0043] In some possible implementations, such as Figure 6 As shown, the microscope objective lens group CC includes a sixteenth lens 116, a seventeenth lens 117, an eighteenth lens 118, a nineteenth lens 119, a twentieth lens 120, a twenty-first lens 121 and a twenty-second lens 122 which are sequentially arranged along the main optical axis. The optical power of the sixteenth lens is positive, the optical power of the seventeenth lens is negative, and the optical power of the eighteenth lens, the optical power of the nineteenth lens, the optical power of the twentieth lens, the optical power of the twenty-first lens and the twenty-second lens are positive.

[0044] In some feasible implementations, the sixteenth lens 116 is a biconvex lens, the seventeenth lens 117 is a biconcave lens, the eighteenth lens 118 and the nineteenth lens 119 are biconvex lenses, the twentieth lens 120 and the twenty-first lens 121 are meniscus positive lenses, and the twenty-second lens 122 is a plano-convex lens.

[0045] After the asymmetric phase difference is corrected twice by the first lens group AA and the second lens group BB, the light beam enters the microscope objective group CC, and the light beam sequentially passes through the sixteenth lens 116 of the double convex lens, the seventeenth lens 117 of the double concave lens, the eighteenth lens 118 and the nineteenth lens 119 of the double convex lens, the twentieth lens 120 and the twenty-first lens 121 of the meniscus positive lens, and the twenty-second lens 122 of the plano-convex lens, and then emerges and forms an image on the image plane. The light beam passing through the microscope objective group CC further eliminates aberrations such as spherical aberration, coma, and distortion, so that the image received on the image plane has better imaging quality.

[0046] In some possible implementations: The focal length f16 of the sixteenth lens and the refractive index n16 of the sixteenth lens satisfy: 300 mm <f16<360mm;n16=1.50; The focal length f17 of the seventeenth lens and the refractive index n17 of the seventeenth lens satisfy: -250mm <f17<-150mm;n17=1.58; The focal length f18 of the eighteenth lens and the refractive index n18 of the eighteenth lens satisfy: 400mm <f18<500mm;n18=1.50; The focal length f19 of the nineteenth lens and the refractive index n19 of the nineteenth lens satisfy: 400mm <f19<500mm;n19=1.50; The focal length f20 of the twentieth lens and the refractive index n20 of the twentieth lens satisfy: 550mm <f20<650mm;n20=1.49; The focal length f21 of the 21st lens and the refractive index n21 of the 21st lens satisfy: 500 mm <f21<600mm;n21=1.62; The focal length f22 of the 22nd lens and the refractive index n22 of the 22nd lens satisfy: 500mm <f22<600mm;n22=1.57。

[0047] like Figure 7 As shown, a schematic diagram of the Seidel coefficient of the microscope objective lens group CC is shown. After the microscope objective lens group CC is set and designed according to the specific surface shapes and parameters of the sixteenth lens 116 to the twenty-second lens 122, since the light beam is corrected for astigmatism by the first lens group AA and the second lens group BB, and the microscope objective lens group CC can further eliminate other aberrations such as spherical aberration, coma, and distortion, Figure 7It can be seen that the light beam emitted by the microscope objective group CC exhibits a small astigmatism.

[0048] In some possible implementations, such as Figure 8 As shown, a first aspheric surface 200 is further provided on the light-incident side surface of the first lens 101 , and a second aspheric surface 300 is further provided on the light-incident side surface of the eleventh lens 111 .

[0049] In the actual application of the imaging system of the lithography machine, the telecentricity of each field of view of the illumination system has certain differences, and the objective lens module of the lithography imaging system needs to maintain a good match with the illumination system so as to effectively improve the uniformity of exposure and thus improve the imaging effect. Among them, adding the first aspheric surface 200 to the light-entering side surface of the first lens 101 can effectively control the telecentricity of the field of view, so that the illumination system and the imaging system have a good telecentricity match; at the same time, setting the first aspheric surface 200 on the light-entering side of the first lens 101 of the first lens group AA can make it easier to design, install, maintain and debug the optical system under the premise of effectively controlling aberrations.

[0050] For example, in the present application, the telecentricity of the field of view of the objective lens module is controlled according to the telecentricity input of the field of view of the illumination system, wherein the telecentricity configuration of the field of view of the illumination system is: 0 field of view 0°, 0.2 field of view 0.3°, 0.4 field of view 0.5°, 0.6 field of view 0.5°, 0.8 field of view 0.3°, 1 field of view 0.55°. Based on the data and associated relationships of the above examples, the parameters of the first aspheric surface 200 are designed to achieve a match between the objective lens module and the illumination system. Fig. 9 , shows a telecentricity curve diagram of the objective lens module of an embodiment of the present application, Fig. 9 The vertical axis of the coordinate system represents the angle in degrees, and the horizontal axis represents the object field of view in millimeters.

[0051] In addition, the objective lens module provided in the embodiment of the present application can also have a larger object-side working distance under the premise of ensuring a large field of view and a large numerical aperture and minimizing the size of the optical lens aperture. In this way, when the objective lens module of the embodiment of the present application is applied to the lithography imaging system of the lithography machine, it can bring more design space to the design of the mask stage in the lithography process.

[0052] For example, according to the above example data, the object side working distance of the objective lens module of the embodiment of the present application is 106 mm, and if the objective lens module is further designed and optimized, the above object side working distance can be further extended.

[0053] For example, in order to further optimize and extend the object side working distance of the objective lens module, the optical lenses of the first lens group AA, the second lens group BB and the microscope objective lens group CC are specifically set according to the parameters in Table 1.

[0054] Table 1

[0055] In the scheme of this embodiment, the first aspheric surface 200 is set as the light incident side surface of the first lens 101, that is, the surface 1 in Table 1, and the second aspheric surface 300 is set as the light incident side surface of the eleventh lens 111, that is, the surface 23 in Table 1. Among them, the surface 1 and the surface 2 before the first lens 101 in Table 1 are used as reference surfaces in the design of the objective lens. For example, when the objective lens module of the embodiment of the present application is applied to the lithography imaging system of the lithography machine for performing the lithography process of the wafer, in order to leave a sufficient safety distance between the surface and the mechanical surface of the mask stage of the lithography machine, the surface 1 and the surface 2 can also be integrated into one surface. If the two are integrated into one surface, it can be presented in Table 1 as the sum of the thickness of the existing surface 1 and the surface 2.

[0056] In addition, the Stop between the fifteenth lens 115 and the sixteenth lens 116 in Table 1 means that a stop is provided between the fifteenth lens 115 and the sixteenth lens 116. The 123 after the twenty-second lens 122 refers to a protective glass provided on the image side of the objective lens module.

[0057] According to the design formula of the aspheric surface, the first aspheric surface 200 and the second aspheric surface 300 are both fifth-order aspheric surfaces. Specific parameters are shown in Table 2.

[0058] Table 2

[0059] In addition, if Fig.10 As shown, it is a wavefront error curve diagram of the image emitted from the objective lens module to the image plane according to the embodiment of the present application, wherein the horizontal axis represents the field of view size in millimeters, and the vertical axis represents the wavefront error in one wavelength. Fig.10 The horizontal line at 0.072 on the vertical axis represents the diffraction limit line. Fig.10 It can be seen from the wavefront error curve and the diffraction limit marking in the comparison image that the root mean square value of the wavefront error is much lower than the diffraction limit, so it can be concluded that the image aberration emitted by the objective lens module of the embodiment of the present application is better controlled and the system performance is excellent.

[0060] Fig.11 The Strehl ratio curve of the output image of the objective lens module of the embodiment of the present application is shown, wherein the horizontal axis represents the field of view size in millimeters, and the vertical axis represents the Strehl ratio. Fig.11 The horizontal line at 0.8 on the vertical axis represents the diffraction limit line. Fig.11 From the Strehl ratio curve and the diffraction limit marking in the contrast image, it can be seen that the Strehl ratio is higher than 0.95 in the entire field of view, and the image has a high imaging quality.

[0061] Fig.12 The figure shows the field curvature curve of the output image of the objective lens module, where the horizontal axis represents the distance of the best image point from the ideal image plane in micrometers, and the vertical axis represents the field of view in millimeters. Fig.13 The figure shows the distortion curve of the output image of the objective lens module. The horizontal axis represents the magnitude of the distortion in percentage, and the vertical axis represents the field of view in millimeters. Fig.12 and Fig.13 It can be seen that the field curvature deviation of the image is small, the distortion is small, and the maximum distortion is about -0.00002081%, which fully meets the working requirements of the objective lens module of the embodiment of the present application as a lithography imaging system of a lithography machine.

[0062] Another aspect of an embodiment of the present application provides a lithography imaging system, comprising any one of the aforementioned objective lens modules.

[0063] The photolithography imaging system using the objective lens module of the embodiment of the present application can provide each optical lens with a smaller optical aperture under the premise of ensuring a large field of view and a large numerical aperture, effectively reduce the lens size of the entire photolithography imaging system, and reduce the processing cost. In addition, the aperture diaphragm located in front of the microscope objective lens group CC can be provided with a smaller diaphragm aperture. When the aperture diaphragm is a variable diaphragm, the design difficulty of the variable diaphragm can be reduced and the processing cost of the variable diaphragm can be reduced. The larger object-side working distance of the objective lens module greatly improves the design space and maintenance space of the mask stage of the photolithography machine. In addition, the first aspheric surface 200 is arranged on the front surface of the first lens 101 of the first lens group AA, and the second aspheric surface 300 is arranged on the front surface of the eleventh lens 111 of the second lens group BB, which can effectively control the incident telecentricity, and has better flexibility when matching and setting the telecentricity of the optical path of the illumination system.

[0064] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An objective lens module, arranged between the object plane and the image plane of a photolithography imaging system, characterized in that: The objective lens module includes a first lens group, a second lens group and a microscope objective lens group which are arranged in sequence from the object plane to the image plane. The first lens group and the second lens group are both double Gaussian structures or double Gaussian derivative structures. The focal length of the first lens group is greater than that of the second lens group.

2. The objective lens module according to claim 1, characterized in that: The focal power p1 of the first lens group, the focal power p2 of the second lens group and the focal power p3 of the microscope objective lens group satisfy the following relationship: 0<|p1|<1 / 5000； 1 / 1000<|p2|<1 / 400； 1 / 200<|p3|<1 / 100； 3<|p3 / p2|<7; The focal length is in millimeters.

3. The objective lens module according to claim 1, characterized in that: The first lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along the main optical axis, the optical power of the first lens and the optical power of the second lens are positive optical powers, the optical power of the third lens, the optical power of the fourth lens and the fifth lens are negative optical powers, and the optical power of the sixth lens and the optical power of the seventh lens are positive optical powers.

4. The objective lens module according to claim 3, characterized in that: The second lens is a plano-convex lens, the third lens is a plano-concave lens, the fourth lens and the fifth lens are biconcave lenses, and the sixth lens and the seventh lens are meniscus positive lenses.

5. The objective lens module according to claim 4, characterized in that: The focal length f1 of the first lens and the refractive index n1 of the first lens satisfy: 300mm <f1<400mm;n1=1.58; The focal length f2 of the second lens and the refractive index n2 of the second lens satisfy: 200mm <f2<300mm;n2=1.52; The focal length f3 of the third lens and the refractive index n3 of the third lens satisfy: -200mm <f3<-100mm;n3=1.60; The focal length f4 of the fourth lens and the refractive index n4 of the fourth lens satisfy: -200mm <f4<-100mm;n4=1.59; The focal length f5 of the fifth lens and the refractive index n5 of the fifth lens satisfy: -200mm <f5<-100mm;n5=1.60; The focal length f6 of the sixth lens and the refractive index n6 of the sixth lens satisfy: 900 mm <f6<1000mm;n6=1.59; The focal length f7 of the seventh lens and the refractive index n7 of the seventh lens satisfy: 380mm <f7<480mm;n7=1.50。 6. The objective lens module according to claim 5, characterized in that: The second lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens arranged in sequence along the main optical axis, the focal power of the eighth lens, the focal power of the ninth lens and the tenth lens is positive, the focal power of the eleventh lens, the focal power of the twelfth lens and the thirteenth lens is negative, and the focal power of the fourteenth lens and the fifteenth lens is positive.

7. The objective lens module according to claim 6, characterized in that: The eighth lens and the ninth lens are positive meniscus lenses, the tenth lens is a biconvex lens, the eleventh lens and the twelfth lens are biconcave lenses, the thirteenth lens is a negative meniscus lens, and the fourteenth lens and the fifteenth lens are biconvex lenses.

8. The objective lens module according to claim 7, characterized in that: The focal length f8 of the eighth lens and the refractive index n8 of the eighth lens satisfy: 2000mm <f8<2600mm;n8=1.62; The focal length f9 of the ninth lens and the refractive index n9 of the ninth lens satisfy: 7000mm <f9<∞;n9=1.60; The focal length f10 of the tenth lens and the refractive index n10 of the tenth lens satisfy: 200mm <f10<300mm;n10=1.60; The focal length f11 of the eleventh lens and the refractive index n11 of the eleventh lens satisfy: -200mm <f11<-150mm;n11=1.60; The focal length f12 of the twelfth lens and the refractive index n12 of the twelfth lens satisfy: -300mm <f12<-200mm;n12=1.57; The focal length f13 of the thirteenth lens and the refractive index n13 of the thirteenth lens satisfy: -700mm <f13<-600mm;n13=1.49; The focal length f14 of the fourteenth lens and the refractive index n14 of the fourteenth lens satisfy: 300 mm <f14<400mm;n14=1.50; The focal length f15 of the fifteenth lens and the refractive index n15 of the fifteenth lens satisfy: 380mm <f15<480mm;n15=1.50。 9. The objective lens module according to claim 1, characterized in that: The microscope objective lens group includes a sixteenth lens, a seventeenth lens, an eighteenth lens, a nineteenth lens, a twentieth lens, a twenty-first lens and a twenty-second lens which are arranged in sequence along the main optical axis. The optical focal power of the sixteenth lens is positive, the optical focal power of the seventeenth lens is negative, and the optical focal power of the eighteenth lens, the optical focal power of the nineteenth lens, the optical focal power of the twentieth lens, the optical focal power of the twenty-first lens and the twenty-second lens are positive.

10. The objective lens module according to claim 9, characterized in that: The sixteenth lens is a biconvex lens, the seventeenth lens is a biconcave lens, the eighteenth lens and the nineteenth lens are biconvex lenses, the twentieth lens and the twenty-first lens are meniscus positive lenses, and the twenty-second lens is a plano-convex lens.

11. The objective lens module according to claim 10, characterized in that: The focal length f16 of the sixteenth lens and the refractive index n16 of the sixteenth lens satisfy: 300 mm <f16<360mm;n16=1.50; The focal length f17 of the seventeenth lens and the refractive index n17 of the seventeenth lens satisfy: -250mm <f17<-150mm;n17=1.58; The focal length f18 of the eighteenth lens and the refractive index n18 of the eighteenth lens satisfy: 400mm <f18<500mm;n18=1.50; The focal length f19 of the nineteenth lens and the refractive index n19 of the nineteenth lens satisfy: 400mm <f19<500mm;n19=1.50; The focal length f20 of the twentieth lens and the refractive index n20 of the twentieth lens satisfy: 550mm <f20<650mm;n20=1.49; The focal length f21 of the 21st lens and the refractive index n21 of the 21st lens satisfy: 500 mm <f21<600mm;n21=1.62; The focal length f22 of the 22nd lens and the refractive index n22 of the 22nd lens satisfy: 500mm <f22<600mm;n22=1.57。 12. The objective lens module according to claim 6, characterized in that: A first aspheric surface is also provided on the light incident side surface of the first lens, and a second aspheric surface is also provided on the light incident side surface of the eleventh lens.

13. A photolithography imaging system, characterized in that: Comprising the objective lens module as described in any one of claims 1-12.

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