An objective lens module and a lithography imaging system

Abstract

The present application provides an objective lens module and a lithographic imaging system, which relate to the technical field of optical imaging. The objective lens module is disposed between the object plane and the image plane of the lithographic imaging system. The objective lens module includes a first lens group, a second lens group, and a microscopic objective lens group that are sequentially arranged from the object plane to the image plane. Both the first lens group and the second lens group are of a double-Gauss structure or both are of a double-Gauss derivative structure, and the focal length of the first lens group is greater than that of the second lens group. It is possible to reduce the aperture size of the optical lens in the objective lens module, increase the object space working distance, and improve the imaging quality while ensuring a large field of view.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and more particularly, to an objective lens module and a lithographic imaging system. Background Art

[0002] A lithography machine is a core device for efficiently replicating tiny and precise integrated circuits on a silicon wafer through a lithography process. The exposure field of view, resolution, and working stability of the lithographic imaging system of the lithography machine directly determine the chip manufacturing ability.

[0003] In the objective lens module of a lithographic imaging system, it is usually required to provide as large a field of view as possible within a limited space size range. The large number of optical lens elements in the objective lens module often brings problems such as a complex structure of the objective lens module and a large clear aperture, which further makes it more difficult in the processing, manufacturing, assembly, and debugging processes of the objective lens module. The reduction in yield caused by manufacturing difficulties also increases the manufacturing cost. Summary of the Invention

[0004] This application provides an objective lens module and a lithographic imaging system. The objective lens module of this application 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 while ensuring a large field of view.

[0005] To achieve the above object, the technical solutions adopted in the embodiments of this application are as follows:

[0006] On the one hand, an embodiment of this application provides an objective lens module configured between the object plane and the image plane of a lithographic imaging system. The objective lens module includes a first lens group, a second lens group, and a microscope objective lens group arranged in sequence from the object plane to the image plane. 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 the focal length of the second lens group.

[0007] In some feasible embodiments, 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 relational expressions:

[0008] 0 < |p1| < 1 / 5000;

[0009] 1 / 1000 < |p2| < 1 / 400;

[0010] 1 / 200 < |p3| < 1 / 100;

[0011] 3 < |p3 / p2| < 7; where the unit of the focal length is millimeter.

[0012] 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 principal 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 optical power of the fifth lens are negative optical powers. The optical power of the sixth lens and the optical power of the seventh lens are positive optical powers.

[0013] 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.

[0014] In some feasible embodiments, 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: 900mm < 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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 a positive optical power, the optical power of the seventeenth lens is a negative optical power, 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 optical powers.

[0019] 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.

[0020] 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.

[0021] In some feasible embodiments, a first aspherical surface is further provided on the light incident side surface of the first lens, and a second aspherical surface is further provided on the light incident side surface of the eleventh lens.

[0022] 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.

[0023] The beneficial effects of the embodiments of the present application include:

[0024] An embodiment of the present application provides 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 - Gaussian structure or a double - Gaussian 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 - 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 that of the second lens group. Through the mutual cooperation of the first lens group and the second lens group, astigmatism of the system can be eliminated. Then, in cooperation with the microscopic objective lens group, the design freedom of the system can be effectively optimized and improved, the object space working distance can be increased, and spherical aberration, coma, distortion and other optical aberrations of the system can be offset. Thus, when the objective lens module provided by the embodiment 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

[0025] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0026] Figure 1 One of the optical path diagrams of an objective lens module provided by an embodiment of the present application;

[0027] Figure 2 The optical path diagram of the first lens group in an objective lens module provided by an embodiment of the present application;

[0028] Figure 3 The Seidel coefficient diagram of the first lens group in an objective lens module provided by an embodiment of the present application;

[0029] Figure 4 The optical path diagram of the second lens group in an objective lens module provided by an embodiment of the present application;

[0030] Figure 5 The Seidel coefficient diagram of the second lens group in an objective lens module provided by an embodiment of the present application;

[0031] Figure 6 The optical path diagram of the microscopic objective lens group in an objective lens module provided by an embodiment of the present application;

[0032] Figure 7 The Seidel coefficient diagram of the microscopic objective lens group in an objective lens module provided by an embodiment of the present application;

[0033] Figure 8 Another optical path diagram of an objective lens module provided by an embodiment of the present application;

[0034] Figure 9 The telecentricity curve graph of an objective lens module provided by an embodiment of the present application;

[0035] Figure 10 The wavefront aberration curve graph of the outgoing image of an objective lens module provided by an embodiment of the present application;

[0036] Figure 11 The Strehl ratio curve graph of the outgoing image of an objective lens module provided by an embodiment of the present application;

[0037] Figure 12 The field curvature curve graph of the outgoing image of an objective lens module provided by an embodiment of the present application;

[0038] Figure 13 The distortion curve graph of the outgoing image of an objective lens module provided by an embodiment of the present application.

[0039] Icons: AA - the first lens group; BB - the second lens group; CC - the microscopic objective lens group; 101 - the first lens; 102 - the second lens; 103 - the third lens; 104 - the fourth lens; 105 - the fifth lens; 106 - the sixth lens; 107 - the seventh lens; 108 - the eighth lens; 109 - the ninth lens; 110 - the tenth lens; 111 - the eleventh lens; 112 - the twelfth lens; 113 - the thirteenth lens; 114 - the fourteenth lens; 115 - the fifteenth lens; 116 - the sixteenth lens; 117 - the seventeenth lens; 118 - the eighteenth lens; 119 - the nineteenth lens; 120 - the twentieth lens; 121 - the twenty - first lens; 122 - the twenty - second lens; 200 - the first aspherical surface; 300 - the second aspherical surface. Detailed implementation manners

[0040] To make the objectives, technical solutions and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. It should be noted that, without conflict, the various features in the embodiments of this application can be combined with each other, and the combined embodiments are still within the protection scope of this application.

[0041] In the description of this application, it should be noted that the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing this application and simplifying the description. Therefore, they should not be construed as limiting this application. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions, and cannot be construed as indicating or implying relative importance.

[0042] On one hand of the embodiments of this application, an objective lens module is provided, which is configured between the object plane and the image plane of a lithographic imaging system, as Figure 1 shown. The objective lens module includes a first lens group AA, a second lens group BB, and a microscopic objective lens group CC arranged in sequence from the object plane to the image plane. Both the first lens group AA and the second lens group BB are of double - Gauss structure or double - Gauss derivative structure, and the focal length of the first lens group is greater than that of the second lens group.

[0043] As Figure 1As shown, in the objective lens module provided in the embodiment of the present application, along the main optical path from the object plane to the image plane, the first lens group AA and the second lens group BB are arranged in front of the microscopic objective lens group CC, where both the first lens group AA and the second lens group BB are of double Gauss structure or double Gauss derived structure. The double Gauss structure and its derived structures are important concepts in optical lens design and are usually applied to the optical design in related fields of camera lenses. The basic structure of the double Gauss structure includes two sets of symmetric lens groups, and each set of lens groups includes at least two lenses. For example, an approximately symmetric layout combination formed by four lenses of positive-negative-negative-positive is used as the double Gauss structure. The symmetric design of the lenses in the double Gauss structure lens group can effectively cancel out aberrations such as distortion and lateral chromatic aberration in the optical path, achieve a certain degree of aberration correction, and is suitable for large aperture systems, with better performance. The double Gauss derived structure refers to further increasing the number of symmetric lenses on the basis of the double Gauss structure to improve the edge image quality and control chromatic aberration, and may be locally asymmetric in design.

[0044] On this basis, in the solution of the present application, through the mutual cooperation of the first lens group AA and the second lens group BB of the double Gauss structure or double Gauss derived structure, 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 in 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 space working distance, and ensure a better imaging effect of the objective lens module.

[0045] The embodiment of the present application provides an objective lens module configured between the object plane and the image plane of a lithographic imaging system. The objective lens module includes a first lens group AA, a second lens group BB, and a microscopic objective lens group CC arranged in sequence from the object plane to the image plane. Both the first lens group AA and the second lens group BB are of double Gauss structure or both are of double Gauss derived structure, 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 Gauss structure or double Gauss derived structure can effectively correct the asymmetric aberrations in the optical path system. The focal length of the first lens group is greater than the focal length of the second lens group. Through the mutual cooperation of the first lens group AA and the second lens group BB, astigmatism of the system can be eliminated. Then, in cooperation with the microscopic objective lens group CC, it can effectively optimize and improve the design freedom of the system, increase the object space working distance, and cancel out optical aberrations such as spherical aberration, coma, and distortion of the system. Thus, the objective lens module provided by the embodiment 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 is reduced, and a better imaging effect of the objective lens module is ensured.

[0046] In some feasible embodiments, 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 microscopic objective lens group satisfy the following relational expressions:

[0047] 0 < |p1| < 1 / 5000;

[0048] 1 / 1000 < |p2| < 1 / 400;

[0049] 1 / 200 < |p3| < 1 / 100;

[0050] 3 < |p3 / p2| < 7; where the unit of the focal length is millimeter.

[0051] Still referring to Figure 1 as shown, the first lens group AA is composed of a combination of multiple 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 transmitted light beam after the combined design of the multiple optical lenses that make up the first lens group AA, and is the equivalent optical power after the combination of the multiple optical lenses that make up the first lens group AA. The absolute value of the optical power is expressed as the inverse proportion of the focal length. In the solution of this application, 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 satisfy the corresponding numerical range limitation requirements, where the unit of the focal length is millimeter. And, 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.

[0052] The objective lens module that meets the above design can achieve an overall reduction in the optical aperture of the entire objective lens module through the design combination of 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 can enable the aperture stop set in front of the microscope objective lens group CC to meet a smaller aperture design.

[0053] It should be noted that the aperture stop, as an optical element that determines the numerical aperture of each field of view in the optical module, the specific setting position of the aperture stop in the optical module largely determines the optical performance of the optical system. For optical lenses with a large field of view and a large numerical aperture, including the objective lens module of the embodiment of this application, in order to ensure the telecentricity of the image space, it is usually selected to set the aperture stop at the optical lens near the image space and with the largest aperture in the objective lens module. Moreover, when the aperture stop adopts a variable aperture stop, by changing the aperture diameter of the variable aperture stop, the system numerical aperture of the objective lens module can be changed to achieve different required imaging exposure effects.

[0054] In the design and manufacture of the variable aperture, the larger the maximum aperture of the variable aperture, the higher the manufacturing difficulty. Since the design of the variable aperture needs to cooperate with the parameters of other optical elements in the optical path system, to reduce the maximum aperture of the variable aperture without affecting the imaging exposure effect, it is necessary to cooperate with the parameters of other optical elements in the objective lens module, and focus on the ratio relationship between the optical power p3 of the microscopic objective lens group and the optical power p2 of the second lens group for cooperative design. In the objective lens module of the embodiment of the present application, through the cooperative design among the various parameters of the above-mentioned optical elements, the design of a variable aperture with a smaller aperture can meet the requirements of the optical system, thereby effectively reducing the design difficulty of the variable aperture, and reducing the design and manufacturing costs of the variable aperture, and further reducing the processing cost of the entire objective lens module.

[0055] In some feasible embodiments, as Figure 2 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 arranged in sequence along the principal optical axis. The optical power of the first lens and the optical power of the second lens are positive optical powers. The optical powers of the third lens, the fourth lens, and the fifth lens are negative optical powers. The optical powers of the sixth lens and the seventh lens are positive optical powers.

[0056] In some feasible embodiments, 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 meniscus positive lenses.

[0057] The incident light beam exits 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 with the above combination of positive and negative optical powers in the first lens group AA. The exiting light beam is preliminarily corrected for the asymmetric aberration in the light beam through the adjustment of the seven lenses with a double-Gauss structure or a double-Gauss diffraction structure in the first lens group AA.

[0058] In some feasible embodiments:

[0059] The focal length f1 of the first lens and the refractive index n1 of the first lens satisfy: 300mm < f1 < 400mm; n1 = 1.58;

[0060] The focal length f2 of the second lens and the refractive index n2 of the second lens satisfy: 200mm < f2 < 300mm; n2 = 1.52;

[0061] The focal length f3 of the third lens and the refractive index n3 of the third lens satisfy: -200mm < f3 < -100mm; n3 = 1.60;

[0062] 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;

[0063] 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;

[0064] 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;

[0065] 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.

[0066] As Figure 3 shown, a schematic diagram of the Seidel coefficients of the first lens group AA is shown. Figure 3 In it, the horizontal axis represents the aberration. From left to right, distinguished by color, they represent spherical aberration, coma, astigmatism, field curvature, and distortion respectively. 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 as described above, due to the symmetry of the multiple optical lenses in the first lens group AA, the astigmatism is corrected, Figure 3 it can be seen from it that the light beam emitted by the first lens group AA exhibits relatively small astigmatism.

[0067] In some feasible embodiments, as Figure 4 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 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.

[0068] In some feasible embodiments, the eighth lens 108 and the ninth lens 109 are meniscus positive lenses, the tenth lens 110 is a biconvex lens, the eleventh lens 111 and the twelfth lens 112 are biconcave lenses, the thirteenth lens 113 is a meniscus negative lens, and the fourteenth lens 114 and the fifteenth lens 115 are biconvex lenses.

[0069] The beam that has been preliminarily corrected for asymmetric aberration by the first lens group AA is incident on the second lens group BB. The beam sequentially passes through the eighth lens 108 and the ninth lens 109 of the meniscus positive lens, the tenth lens 110 of the biconvex lens, the eleventh lens 111 and the twelfth lens 112 of the biconcave lens, the thirteenth lens 113 of the meniscus negative lens, the fourteenth lens 114 and the fifteenth lens 115 of the biconvex lens, and then exits. The exiting beam is further adjusted by the double Gauss structure or the double Gauss diffraction structure of the second lens group BB to further correct the asymmetric aberration in the beam.

[0070] In some feasible embodiments:

[0071] The focal length f8 of the eighth lens and the refractive index n8 of the eighth lens satisfy: 2000 mm < f8 < 2600 mm; n8 = 1.62;

[0072] The focal length f9 of the ninth lens and the refractive index n9 of the ninth lens satisfy: 7000 mm < f9 < ∞; n9 = 1.60;

[0073] The focal length f10 of the tenth lens and the refractive index n10 of the tenth lens satisfy: 200 mm < f10 < 300 mm; n10 = 1.60;

[0074] The focal length f11 of the eleventh lens and the refractive index n11 of the eleventh lens satisfy: -200 mm < f11 < -150 mm; n11 = 1.60;

[0075] The focal length f12 of the twelfth lens and the refractive index n12 of the twelfth lens satisfy: -300 mm < f12 < -200 mm; n12 = 1.57;

[0076] The focal length f13 of the thirteenth lens and the refractive index n13 of the thirteenth lens satisfy: -700 mm < f13 < -600 mm; n13 = 1.49;

[0077] The focal length f14 of the fourteenth lens and the refractive index n14 of the fourteenth lens satisfy: 300 mm < f14 < 400 mm; n14 = 1.50;

[0078] The focal length f15 of the fifteenth lens and the refractive index n15 of the fifteenth lens satisfy: 380 mm < f15 < 480 mm; n15 = 1.50.

[0079] As Figure 5 shown, a schematic diagram of the Seidel coefficients 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 above-mentioned eighth lens 108 to 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 from

[0080] In some feasible embodiments, such as Figure 6 shown, the microscopic 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 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.

[0081] In some feasible embodiments, 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.

[0082] The light beam after being corrected for asymmetric aberration twice by the first lens group AA and the second lens group BB is incident on the microscopic objective lens group CC. The light beam sequentially passes through the sixteenth lens 116 of the biconvex lens, the seventeenth lens 117 of the biconcave lens, the eighteenth lens 118 and the nineteenth lens 119 of the biconvex 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 exits, and forms an image on the image plane. The light beam passing through the microscopic objective lens group CC further corrects aberrations such as spherical aberration, coma, and distortion, so that the image received on the image plane has better imaging quality.

[0083] In some feasible embodiments:

[0084] The focal length f16 of the sixteenth lens and the refractive index n16 of the sixteenth lens satisfy: 300mm < f16 < 360mm; n16 = 1.50;

[0085] The focal length f17 of the seventeenth lens and the refractive index n17 of the seventeenth lens satisfy: - 250mm < f17 < - 150mm; n17 = 1.58;

[0086] The focal length f18 of the eighteenth lens and the refractive index n18 of the eighteenth lens satisfy: 400mm < f18 < 500mm; n18 = 1.50;

[0087] The focal length f19 of the nineteenth lens and the refractive index n19 of the nineteenth lens satisfy: 400mm < f19 < 500mm; n19 = 1.50;

[0088] The focal length f20 of the twentieth lens and the refractive index n20 of the twentieth lens satisfy: 550mm < f20 < 650mm; n20 = 1.49;

[0089] The focal length f21 of the twenty - first lens and the refractive index n21 of the twenty - first lens satisfy: 500mm < f21 < 600mm; n21 = 1.62;

[0090] The focal length f22 of the twenty - second lens and the refractive index n22 of the twenty - second lens satisfy: 500mm < f22 < 600mm; n22 = 1.57.

[0091] As Figure 7 shown, a schematic diagram of the Seidel coefficients of the microscopic objective lens group CC is shown. After the microscopic objective lens group CC is set and designed according to the specific surface profiles and parameters of the above - mentioned sixteenth lens 116 to twenty - second lens 122, since the astigmatism is corrected by the first lens group AA and the second lens group BB, and the microscopic objective lens group CC can further eliminate other aberrations such as spherical aberration, coma, and distortion, Figure 7 it can be seen from

[0092] In some feasible embodiments, as Figure 8 shown, a first aspherical surface 200 is further provided on the incident - light side surface of the first lens 101, and a second aspherical surface 300 is further provided on the incident - light side surface of the eleventh lens 111.

[0093] In the actual application of the imaging system of the lithography machine, the telecentricity of each field of view of the illumination system has a certain difference. The objective lens module of the lithography imaging system needs to be well - matched with the illumination system in order to effectively improve the exposure uniformity and thus enhance the imaging effect. Among them, adding the first aspherical surface 200 on the incident - light 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 aspherical surface 200 on the incident - light side of the first lens 101 of the first lens group AA can, on the premise of effectively controlling aberrations, also make it easier for the design, installation, maintenance, and debugging of the optical system.

[0094] Exemplarily, in the solution of this application, the telecentricity of the objective lens module is controlled according to the input of the telecentricity of the field of view of the illumination system. Among them, 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°. According to the above - mentioned example data and the correlation relationship, the parameters of the first aspherical surface 200 are designed to achieve the match between the objective lens module and the illumination system. As Figure 9 shown, a telecentricity curve graph of the objective lens module of the embodiment of this application is shown, Figure 9 where the vertical axis of the coordinate axis in

[0095] In addition, the objective lens module provided by the embodiments of the present application can also have a larger object-side working distance on the premise of ensuring a large field of view and a large numerical aperture and minimizing the aperture size of the optical lens as much as possible. Thus, when the objective lens module of the embodiments of the present application is applied to the lithography imaging system of a lithography machine, it can bring a larger design space to the design of the mask stage in the lithography process.

[0096] Exemplarily, according to the above example data, the object-side working distance of the objective lens module of the embodiments of the present application is 106 mm, and furthermore, if further design optimization is carried out on the objective lens module, the above object-side working distance can be further extended.

[0097] Exemplarily, in order to further optimize and extend the object-side working distance of the objective lens module, specific settings are made for each optical lens of the first lens group AA, the second lens group BB, and the microscopic objective lens group CC according to the parameters in Table 1.

[0098] Table 1

[0099]

[0100] In the solution of this embodiment, the first aspheric surface 200 is set as the light-incident side surface of the first lens 101, that is, 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, surface 23 in Table 1. Among them, surface 1 and surface 2 before the first lens 101 in Table 1 are used as reference surfaces in the objective lens design. For example, when the objective lens module of the embodiments of the present application is applied to the wafer lithography process in the lithography imaging system of a lithography machine, in order to leave enough safety distance between the mechanical surface of the mask stage of the lithography machine, surface 1 and surface 2 can also be integrated into one surface. If the two are integrated into one surface, it only needs to show the sum of the thicknesses of the existing surface 1 and surface 2 in Table 1.

[0101] In addition, Stop between the fifteenth lens 115 and the sixteenth lens 116 in Table 1 means that a diaphragm is provided between the fifteenth lens 115 and the sixteenth lens 116. 123 after the twenty-second lens 122 refers to the protective glass provided on the image side of the objective lens module.

[0102] According to the aspheric design formula, both the first aspheric surface 200 and the second aspheric surface 300 are fifth-order aspheric surfaces. The specific parameters are shown in Table 2.

[0103] Table 2

[0104]

[0105] In addition, as Figure 10As shown, it is a wavefront aberration curve graph of the image emitted from the objective lens module of the embodiment of the present application to the image plane. Among them, the horizontal axis represents the field of view size, with the unit of millimeter, and the vertical axis represents the wavefront aberration, with the unit of one wavelength. Figure 10 The horizontal line at 0.072 on the vertical axis in it represents the diffraction limit marking line. From Figure 10 By comparing the wavefront aberration curve of the image with the diffraction limit marking line in it, it can be seen that the root mean square value of the wavefront error is much lower than the diffraction limit. Therefore, it can be concluded that the aberration control of the image formed by the objective lens module of the embodiment of the present application is better, and the system performance is excellent.

[0106] Figure 11 As shown, it is a Strehl ratio curve graph of the image emitted from the objective lens module of the embodiment of the present application. Among them, the horizontal axis represents the field of view size, with the unit of millimeter, and the vertical axis represents the Strehl ratio. Figure 11 In it, the horizontal line at 0.8 on the vertical axis represents the diffraction limit marking line. From Figure 11 By comparing the Strehl ratio curve of the image with the diffraction limit marking line in it, 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.

[0107] Figure 12 As shown, it is a field curvature curve graph of the image emitted from the objective lens module. Among them, the horizontal axis represents the distance of the best image point deviating from the ideal image plane, with the unit of micrometer, and the vertical axis represents the field of view size, with the unit of millimeter. Figure 13 As shown, it is a distortion curve graph of the image emitted from the objective lens module. Among them, the horizontal axis represents the magnitude of distortion, in percentage, and the vertical axis represents the field of view size, with the unit of millimeter. Through Figure 12 and Figure 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 lithographic imaging system of a lithography machine.

[0108] On the other hand, the embodiment of the present application provides a lithographic imaging system, including the objective lens module of any one of the foregoing.

[0109] The lithographic imaging system applying the objective lens module of the embodiment of the present application can provide smaller optical apertures for each optical lens on the premise of ensuring a large field of view and a large numerical aperture, effectively reducing the lens size of the entire lithographic imaging system and lowering the processing cost. Moreover, it can provide a smaller aperture stop diameter for the aperture stop located in front of the microscope objective lens group CC. When the aperture stop is a variable aperture stop, it can reduce the design difficulty of the variable aperture stop and lower the processing cost of the variable aperture stop. With the relatively large object-side working distance of the objective lens module, the design space and maintenance space of the mask stage of the lithography machine are greatly improved. In addition, by providing the first aspherical surface 200 on the front surface of the first lens 101 of the first lens group AA and the second aspherical surface 300 on the front surface of the eleventh lens 111 of the second lens group BB, the incident telecentricity can be effectively controlled, and there is better flexibility when matching with the telecentricity of the illumination system optical path.

[0110] The foregoing are only the preferred embodiments of the present application and are 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 within the protection scope of the present application.

Claims

1. An objective lens module is disposed between the object plane and the image plane of a lithographic imaging system, and is characterized in that, The objective lens module is composed of a first lens group, a second lens group, and a microscopic objective lens group arranged in sequence from the object plane to the image plane. Both the first lens group and the second lens group are of double-Gauss structure or 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 is composed of 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 principal optical axis. The optical power of the first lens and the second lens is positive optical power, the optical power of the third lens, the fourth lens, and the fifth lens is negative optical power, and the optical power of the sixth lens and the seventh lens is positive optical power; The second lens group is composed of 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 ninth lens, and the tenth lens is positive optical power, the optical power of the eleventh lens, the twelfth lens, and the thirteenth lens is negative optical power, and the optical power of the fourteenth lens and the fifteenth lens is positive optical power; The microscopic objective lens group is composed of 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 optical power, the optical power of the seventeenth lens is negative optical power, and the optical power of the eighteenth lens, the nineteenth lens, the twentieth lens, the twenty-first lens, and the twenty-second lens is positive optical power.

2. The objective lens module according to claim 1, characterized in that, 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 microscopic objective lens group satisfy the following relational formula: 0<|p1|<1 / 5000； 1 / 1000<|p2|<1 / 400； 1 / 200<|p3|<1 / 100； 3 < |p3 / p2| < 7; Among them, the unit of the focal length is millimeter.

3. The objective lens module according to claim 1, 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.

4. The objective lens module according to claim 3, 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: 900mm < 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.

5. The objective lens module according to claim 1, characterized in that, 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.

6. The objective lens module according to claim 5, wherein, 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: 300mm < 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.

7. The objective lens module according to claim 1, 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.

8. The objective lens module according to claim 7, wherein The focal length f16 of the sixteenth lens and the refractive index n16 of the sixteenth lens satisfy: 300mm < 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 twenty-first lens and the refractive index n21 of the twenty-first lens satisfy: 500mm < f21 < 600mm; n21 = 1.62; The focal length f22 of the twenty-second lens and the refractive index n22 of the twenty-second lens satisfy: 500mm < f22 < 600mm; n22 = 1.

57.

9. The objective lens module according to claim 1, characterized in that, A first aspherical surface is further provided on the light incident side surface of the first lens, and a second aspherical surface is further provided on the light incident side surface of the eleventh lens.

10. A lithographic imaging system, characterized in that, It includes the objective lens module according to any one of claims 1-9.

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