Fixed focus optical system

Abstract

The utility model discloses a fixed-focus optical system which is provided with an object side and an image side which are oppositely arranged along the direction of an optical axis. The fixed-focus optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a diaphragm, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, a fifteenth lens and a sixteenth lens which are sequentially arranged from the object side to the image side. Through mutual combination of different lenses and reasonable distribution of positive and negative focal power, the resolution ratio is high, the light transmission effect is better, and a large view field and a large target surface are provided.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, in particular to a fixed-focus optical system. Background Art

[0002] With the rapid development of microelectronics technology in recent years, there are more and more scenarios for the use of large-scale integrated circuits, so the demand for microelectronic devices and micro-processing technology is also increasing. With its wide application field and rapid technological updates, photolithography technology is driving the rapid development of fine processing technology. The photolithography machine uses a technology similar to photo printing to print the fine graphics on the mask onto the silicon wafer through light exposure, which is applied in chip manufacturing, LED manufacturing and packaging.

[0003] With the continuous updating of lithography technology, there is a requirement to expose more precise lines on larger chip areas (resolution requirements). Therefore, the demand for lithography lenses used in large exposure fields is also increasing. However, there are currently few such lens products that have a large field of view, large target area and high resolution. Utility Model Content

[0004] The main purpose of the utility model is to provide a fixed-focus projection optical system, aiming to reduce distortion, improve resolution, and provide a large field of view and a large target surface.

[0005] To achieve the above-mentioned object, the utility model proposes a fixed-focus projection optical system, wherein the fixed-focus optical system has an object side and an image side which are arranged opposite to each other along the optical axis direction, and the fixed-focus optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a stop, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, a fifteenth lens and a sixteenth lens which are arranged in sequence from the object side to the image side;

[0006] wherein the first lens has negative optical power;

[0007] The second lens has positive optical power;

[0008] The third lens has positive optical power;

[0009] The fourth lens has positive refractive power;

[0010] The fifth lens has positive optical power;

[0011] The sixth lens has positive optical power;

[0012] The seventh lens has negative optical power;

[0013] The eighth lens has negative optical power;

[0014] The ninth lens has a negative focal power;

[0015] The tenth lens has a negative focal power;

[0016] The eleventh lens has a positive focal power;

[0017] The twelfth lens has a positive focal power;

[0018] The thirteenth lens has a positive focal power;

[0019] The fourteenth lens has a positive focal power;

[0020] The fifteenth lens has a positive focal power;

[0021] The sixteenth lens has a negative focal power.

[0022] In one embodiment, the fixed-focus optical system has a focal length of f, the first lens has a focal length of f1, the second lens has a focal length of f2, the third lens has a focal length of f3, the fourth lens has a focal length of f4, the fifth lens has a focal length of f5, the sixth lens has a focal length of f6, the seventh lens has a focal length of f7, the eighth lens has a focal length of f8, the ninth lens has a focal length of f9, the tenth lens has a focal length of f10, the eleventh lens has a focal length of f11, the twelfth lens has a focal length of f12, the thirteenth lens has a focal length of f13, the fourteenth lens has a focal length of f14, the fifteenth lens has a focal length of f15, and the sixteenth lens has a focal length of f16, and the following relationships are satisfied:

[0023] 0.1 < |f1 / f| < 0.2, 0.5 < |f2 / f| < 0.6, 0.2 < |f3 / f| < 0.3, 0.2 < |f4 / f| < 0.3, 0.2 < |f5 / f| < 0.3, 0.3 < |f6 / f| < 0.4, 0.1 < |f7 / f| < 0.2, 0.4 < |f8 / f| < 0.5, 0.4 < |f9 / f| < 0.5, 0.1 < |f10 / f| < 0.2, 0.3 < |f11 / f| < 0.4, 0.2 < |f12 / f| < 0.3, 0.2 < |f13 / f| < 0.3, 0.2 < |f14 / f| < 0.3, 0.5 < |f15 / f| < 0.6, 0.1 < |f16 / f| < 0.2.

[0024] In one embodiment, the object side surface of the first lens is concave, and the image side surface is concave;

[0025] The object side surface of the second lens is concave, and the image side surface is convex;

[0026] The object side surface of the third lens is concave, and the image side surface is convex;

[0027] The object side surface of the fourth lens is convex, and the image side surface is convex;

[0028] The object side surface of the fifth lens is convex, and the image side surface is concave;

[0029] The object side surface of the sixth lens is convex, and the image side surface is concave;

[0030] The object side surface of the seventh lens is convex, and the image side surface is concave;

[0031] The object side surface of the eighth lens is convex, and the image side surface is concave;

[0032] The object side surface of the ninth lens is concave, and the image side surface is convex;

[0033] The object side surface of the tenth lens is concave, and the image side surface is convex;

[0034] The object side surface of the eleventh lens is concave, and the image side surface is convex;

[0035] The object side surface of the twelfth lens is concave, and the image side surface is convex;

[0036] The object side surface of the thirteenth lens is convex, and the image side surface is convex;

[0037] The object side surface of the fourteenth lens is convex, and the image side surface is concave;

[0038] The object side surface of the fifteenth lens is convex, and the image side surface is concave;

[0039] The object side surface of the sixteenth lens is concave, and the image side surface is concave.

[0040] In one embodiment, the fixed-focus optical system includes two lens groups that are respectively located on both sides of the diaphragm along the optical axis direction and are symmetrically arranged. One of the lens groups is composed of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens, and the other lens group is composed of the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens, the fourteenth lens, the fifteenth lens, and the sixteenth lens.

[0041] In one embodiment, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens, the fourteenth lens, the fifteenth lens, and the sixteenth lens are all set as glass spherical lenses.

[0042] In one embodiment, the focal length of the fixed-focus optical system is f, and the overall optical length of the fixed-focus optical system is TTL, and the following conditions are satisfied:

[0043] 0.5 < TTL / f < 0.6, 800 mm < TTL < 900 mm.

[0044] In one embodiment, the numerical aperture of the image space of the fixed-focus optical system is NA, and the f-number is F, and the following conditions are satisfied:

[0045] NA ≥ 0.15, 3.3 ≤ F < 4.

[0046] In one embodiment, the refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, the refractive index of the seventh lens is n7, the refractive index of the eighth lens is n8, the refractive index of the ninth lens is n9, the refractive index of the tenth lens is n10, the refractive index of the eleventh lens is n11, the refractive index of the twelfth lens is n12, the refractive index of the thirteenth lens is n13, the refractive index of the fourteenth lens is n14, the refractive index of the fifteenth lens is n15, and the refractive index of the sixteenth lens is n16, and the following conditions are satisfied:

[0047] 1.6 < n1 < 1.7, 1.6 < n2 < 1.7, 1.45 < n3 < 1.55, 1.45 < n4 < 1.55, 1.45 < n5 < 1.55, 1.45 < n6 < 1.55, 1.6 < n7 < 1.7, 1.6 < n8 < 1.7, 1.6 < n9 < 1.7, 1.6 < n10 < 1.7, 1.45 < n11 < 1.55, 1.45 < n12 < 1.55, 1.45 < n13 < 1.55, 1.45 < n14 < 1.55, 1.6 < n15 < 1.7, 1.6 < n16 < 1.7.

[0048] In one embodiment, the radius of curvature of the object side surface of the first lens is R2, the radius of curvature of the image side surface is R3, the radius of curvature of the object side surface of the second lens is R4, the radius of curvature of the image side surface is R5, the radius of curvature of the object side surface of the third lens is R6, the radius of curvature of the image side surface is R7, the radius of curvature of the object side surface of the fourth lens is R8, the radius of curvature of the image side surface is R9, the radius of curvature of the object side surface of the fifth lens is R10, the radius of curvature of the image side surface is R11, the radius of curvature of the object side surface of the sixth lens is R12, the radius of curvature of the image side surface is R13, the radius of curvature of the object side surface of the seventh lens is R14, the radius of curvature of the image side surface is R15, the radius of curvature of the object side surface of the eighth lens is R16, the radius of curvature of the image side surface is R17, the radius of curvature of the object side surface of the ninth lens is R19, the radius of curvature of the image side surface is R20, the radius of curvature of the object side surface of the tenth lens is R21, the radius of curvature of the image side surface is R22, the radius of curvature of the object side surface of the eleventh lens is R23, the radius of curvature of the image side surface is R24, the radius of curvature of the object side surface of the twelfth lens is R25, the radius of curvature of the image side surface is R26, the radius of curvature of the object side surface of the thirteenth lens is R27, the radius of curvature of the image side surface is R28, the radius of curvature of the object side surface of the fourteenth lens is R29, the radius of curvature of the image side surface is R30, the radius of curvature of the object side surface of the fifteenth lens is R31, the radius of curvature of the image side surface is R32, the radius of curvature of the object side surface of the sixteenth lens is R33, the radius of curvature of the image side surface is R34, and the following conditions are satisfied:

[0049] 235 mm < R2 < -225 mm, 395 mm < R3 < 405 mm, -175 mm < R4 < -160 mm, -145 mm < R5 < -135 mm, -710 mm < R6 < -695 mm, -150 mm < R7 < -140 mm, 225 mm < R8 < 235 mm, -1450 mm < R9 < -1350 mm, 165 mm < R10 < 175 mm, 3650 mm < R11 < 3720 mm, 135 mm < R12 < 145 mm, 270 mm < R13 < 280 mm, 935 mm < R14 < 950 mm, 100 mm < R15 < 110 mm, 100 mm < R16 < 110 mm, 80 mm < R17 < 90 mm, -90 mm < R19 < -80 mm, -110 mm < R20 < -100 mm, -110 mm < R21 < -100 mm, -950 mm < R22 < -935 mm, -280 mm < R23 < -270 mm, -145 mm < R24 < -135 mm, -3720 mm < R25 < -3650 mm, -175 mm < R26 < -165 mm, 1350 mm < R27 < 1450 mm, -235 mm < R28 < -225 mm, 140 mm < R29 < 150 mm, 695 mm < R30 < 710 mm, 135 mm < R31 < 145 mm, 160 mm < R32 < 175 mm, -405 mm < R33 < -395 mm, 225 mm < R34 < 235 mm.

[0050] In one embodiment, the thickness of the first lens is G1, the thickness of the second lens is G2, the thickness of the third lens is G3, the thickness of the fourth lens is G4, the thickness of the fifth lens is G5, the thickness of the sixth lens is G6, the thickness of the seventh lens is G7, the thickness of the eighth lens is G8, the thickness of the ninth lens is G9, the thickness of the tenth lens is G10, the thickness of the eleventh lens is G11, the thickness of the twelfth lens is G12, the thickness of the thirteenth lens is G13, the thickness of the fourteenth lens is G14, the thickness of the fifteenth lens is G15, the thickness of the sixteenth lens is G16, and the following conditions are satisfied:

[0051] 7 mm < G1 < 8 mm, 34 mm < G2 < 36 mm, 28 mm < G3 < 30 mm, 23 mm < G4 < 30 mm, 25 mm < G5 < 30 mm, 15 mm < G6 < 20 mm, 5 mm < G7 < 8 mm, 6 mm < G8 < 8 mm, 6 mm < G9 < 8 mm, 5 mm < G10 < 8 mm, 15 mm < G11 < 20 mm, 25 mm < G12 < 30 mm, 23 mm < G13 < 30 mm, 28 mm < G14 < 30 mm, 34 mm < G15 < 36 mm, 7 mm < G16 < 8 mm.

[0052] The technical solution of the present utility model provides a large field of view by setting the first lens 1 with a negative focal power to improve the light collection effect. The aperture stop is arranged between the eighth lens 8 and the ninth lens 9, which can adjust the field of view size, block off-axis light, avoid the influence of off-axis light on the imaging quality, improve the image quality, and enable the lens to have a large light throughput. By comprehensively setting the focal powers of each lens, the lens can well control the light trend, reduce distortion while introducing more light, correct spherical aberration and coma, and through the mutual combination of different lenses and reasonable distribution of positive and negative focal powers, it has high resolution, better light transmission effect, and provides a large field of view and a large target surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0054] Figure 1 It is a schematic structural diagram of an embodiment of a fixed-focus optical system provided by the present utility model;

[0055] Figure 2 It is Figure 1 a schematic diagram of the MTF curve of an embodiment of a fixed-focus projection optical system in

[0056] Figure 3 It is Figure 1 a TFM schematic diagram of an embodiment of a fixed-focus projection optical system in

[0057] Figure 4 It is Figure 1 a spot diagram of an embodiment of a fixed-focus projection optical system in

[0058] Figure 5 It is Figure 1 a field curvature / distortion schematic diagram of an embodiment of a fixed-focus projection optical system in

[0059] Explanation of the reference numerals in the drawings:

[0060] 100, fixed-focus projection optical system; 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 6, sixth lens; 7, seventh lens; 8, eighth lens; 9, ninth lens; 10, tenth lens; 11, eleventh lens; 12, twelfth lens; 13, thirteenth lens; 14, fourteenth lens; 15, fifteenth lens; 16, sixteenth lens; 17, first lens group; 18, second lens group.

[0061] The realization of the object, functional features and advantages of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0062] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0063] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present utility model, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0064] In addition, if there are descriptions such as "first" and "second" involved in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, or solution B, or the solution where A and B are satisfied simultaneously. In addition, the technical solutions between the embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0065] With the continuous updating of lithography technology, there is a requirement to expose more precise lines on larger chip areas (resolution requirements). Therefore, the demand for lithography lenses used in large exposure fields is also increasing. However, there are currently few such lens products that have a large field of view, large target area and high resolution.

[0066] In order to solve the above problems, the present invention proposes a fixed-focus projection optical system 100 .

[0067] First of all, it is important to understand that the focal power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power, the stronger the ability to bend light, and the smaller the absolute value of the focal power, the weaker the ability to bend light. When the focal power is a positive number, the refraction of light is convergent; when the focal power is a negative number, the refraction of light is divergent. The focal power can be used to characterize a certain refractive surface of a lens, a certain lens, or a system formed by multiple lenses.

[0068] See also Figure 1 In one embodiment of the utility model, the fixed-focus optical system has an object side and an image side which are arranged opposite to each other along the optical axis direction, and the fixed-focus optical system is composed of a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a stop, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a twelfth lens 12, a thirteenth lens 13, a fourteenth lens 14, a fifteenth lens 15 and a sixteenth lens 16 which are arranged in sequence from the object side to the image side, wherein the first lens 1 has a negative optical power, and the second lens 2 has a positive optical power, The third lens 3 has positive focal power, the fourth lens 4 has positive focal power, the fifth lens 5 has positive focal power, the sixth lens 6 has positive focal power, the seventh lens 7 has negative focal power, the eighth lens 8 has negative focal power, the ninth lens 9 has negative focal power, the tenth lens 10 has negative focal power, the eleventh lens 11 has positive focal power, the twelfth lens 12 has positive focal power, the thirteenth lens 13 has positive focal power, the fourteenth lens 14 has positive focal power, the fifteenth lens 15 has positive focal power, and the sixteenth lens 16 has negative focal power.

[0069] The technical solution of the present utility model provides a large field of view by setting the first lens 1 with a negative focal power to improve the light collection effect. The aperture stop is arranged between the eighth lens 8 and the ninth lens 9, which can adjust the field of view size, block off-axis light, avoid the influence of off-axis light on the imaging quality, improve the image quality, and enable the lens to have a large light throughput. By comprehensively setting the focal powers of each lens, the lens can well control the light trend, reduce distortion while introducing more light, correct spherical aberration and coma, and through the mutual combination of different lenses and reasonable distribution of positive and negative focal powers, it has high resolution, better light transmission effect, and provides a large field of view and a large target surface.

[0070] In an embodiment of the present utility model, it should be understood that the focal length refers to the distance from the rear surface of the lens to the image plane in the optical system. The focal length determines the magnification and viewing angle of the image, and the focal power is the reciprocal of the focal length. The focal length of the fixed-focus optical system is f, the focal length of the first lens 1 is f1, the focal length of the second lens 2 is f2, the focal length of the third lens 3 is f3, the focal length of the fourth lens 4 is f4, the focal length of the fifth lens 5 is f5, the focal length of the sixth lens 6 is f6, the focal length of the seventh lens 7 is f7, the focal length of the eighth lens 8 is f8, the focal length of the ninth lens 9 is f9, the focal length of the tenth lens 10 is f10, the focal length of the eleventh lens 11 is f11, the focal length of the twelfth lens 12 is f12, the focal length of the thirteenth lens 13 is f13, the focal length of the fourteenth lens 14 is f14, the focal length of the fifteenth lens 15 is f15, and the focal length of the sixteenth lens 16 is f16, and the following relationships are satisfied: 0.1 < |f1 / f| < 0.2, 0.5 < |f2 / f| < 0.6, 0.2 < |f3 / f| < 0.3, 0.2 < |f4 / f| < 0.3, 0.2 < |f5 / f| < 0.3, 0.3 < |f6 / f| < 0.4, 0.1 < |f7 / f| < 0.2, 0.4 < |f8 / f| < 0.5, 0.4 < |f9 / f| < 0.5, 0.1 < |f10 / f| < 0.2, 0.3 < |f11 / f| < 0.4, 0.2 < |f12 / f| < 0.3, 0.2 < |f13 / f| < 0.3, 0.2 < |f14 / f| < 0.3, 0.5 < |f15 / f| < 0.6, 0.1 < |f16 / f| < 0.2; By the mutual combination of different lenses and their reasonable distribution of focal powers, the resolution of the fixed-focus projection optical system 100 is improved.

[0071] In order to make the first lens 1 have a negative focal power, the second lens 2 have a positive focal power, the third lens 3 have a positive focal power, the fourth lens 4 have a positive focal power, the fifth lens 5 have a positive focal power, the sixth lens 6 have a positive focal power, the seventh lens 7 have a negative focal power, the eighth lens 8 have a negative focal power, the ninth lens 9 have a negative focal power, the tenth lens 10 have a negative focal power, the eleventh lens 11 have a positive focal power, the twelfth lens 12 have a positive focal power, the thirteenth lens 13 have a positive focal power, the fourteenth lens 14 have a positive focal power, the fifteenth lens 15 have a positive focal power, and the sixteenth lens 16 have a negative focal power, the object side surface of the first lens 1 is concave, and the image side surface is concave; the object side surface of the second lens 2 is concave, and the image side surface is convex; the object side surface of the third lens 3 is concave, and the image side surface is convex; the object side surface of the fourth lens 4 is convex, and the image side surface is convex; the object side surface of the fifth lens 5 is convex, and the image side surface is concave; the object side surface of the sixth lens 6 is convex, and the image side surface is concave; the object side surface of the seventh lens 7 is convex, and the image side surface is concave; the object side surface of the eighth lens 8 is convex, and the image side surface is concave; the object side surface of the ninth lens 9 is concave, and the image side surface is convex; the object side surface of the tenth lens 10 is concave, and the image side surface is convex; the object side surface of the eleventh lens 11 is concave, and the image side surface is convex; the object side surface of the twelfth lens 12 is concave, and the image side surface is convex; the object side surface of the thirteenth lens 13 is convex, and the image side surface is convex; the object side surface of the fourteenth lens 14 is convex, and the image side surface is concave; the object side surface of the fifteenth lens 15 is convex, and the image side surface is concave; the object side surface of the sixteenth lens 16 is concave, and the image side surface is concave.

[0072] In an embodiment of the present invention, the fixed-focus optical system includes two lens groups that are symmetrically arranged on both sides of the aperture along the optical axis direction. One of the lens groups is composed of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, and the eighth lens 8, and the other lens group is composed of the ninth lens 9, the tenth lens 10, the eleventh lens 11, the twelfth lens 12, the thirteenth lens 13, the fourteenth lens 14, the fifteenth lens 15, and the sixteenth lens 16. By symmetrically designing the two lens groups, a double telecentric structure is formed, which can minimize distortion and make the image more accurately reflect the actual shape of the object, so as to reduce the magnification error and alignment error caused by the position change of the reticle and the wafer.

[0073] In order to reduce costs, in an embodiment of the present utility model, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11, the twelfth lens 12, the thirteenth lens 13, the fourteenth lens 14, the fifteenth lens 15, and the sixteenth lens 16 are all set as glass spherical lenses. On the basis of ensuring the effectiveness, while reducing various optical aberrations, the chromatic aberration of the system is effectively suppressed. At the same time, because glass lenses are not easily affected by thermal expansion and contraction, glass lenses can well resist the problem of lens thermal deformation and maintain the high precision of the lens for a long time. In addition, compared with aspherical lenses, they are easier to manufacture and have lower costs.

[0074] In an embodiment of the present utility model, the overall optical length of the fixed-focus optical system, that is, the distance from the object side of the first lens 11 to the image side of the sixteenth lens 16 is TTL, and the focal length of the fixed-focus optical system is f, and it satisfies: 0.5 < TTL / f < 0.6, 800 mm < TTL < 900 mm; By restricting the overall optical length of the fixed-focus optical system, it helps to better match with other lithography machine components (such as mask tables, wafer tables, etc.), ensures the coordinated operation of the entire system, and within a limited space, the limited overall optical length helps to optimize the system layout, reduce space occupation, and facilitate installation.

[0075] In an embodiment of the present utility model, the image-side numerical aperture of the fixed-focus optical system is NA, and the aperture value is F, and it satisfies the following conditions: NA ≥ 0.15, 3.3 ≤ F < 4. When the aperture value F of the fixed-focus projection optical system 100 is within this range, the resolution and contrast performance of the lens are optimal, and the lens has a large light transmission, making it easier to achieve a large target surface. In addition, it can be understood that the image-side numerical aperture is an important parameter used to describe the light-gathering ability of the objective lens. The larger the image-side numerical aperture, the stronger the light-gathering ability of the objective lens, and thus higher resolution and contrast can be achieved. By restricting the image-side numerical aperture, the resolution of the fixed-focus optical system is improved.

[0076] In an embodiment of the present utility model, the refractive index of the first lens 1 is n1, the refractive index of the second lens 2 is n2, the refractive index of the third lens 3 is n3, the refractive index of the fourth lens 4 is n4, the refractive index of the fifth lens 5 is n5, the refractive index of the sixth lens 6 is n6, the refractive index of the seventh lens 7 is n7, the refractive index of the eighth lens 8 is n8, the refractive index of the ninth lens 9 is n9, the refractive index of the tenth lens 10 is n10, the refractive index of the eleventh lens 11 is n11, the refractive index of the twelfth lens 12 is n12, the refractive index of the thirteenth lens 13 is n13, the refractive index of the fourteenth lens 14 is n14, the refractive index of the fifteenth lens 15 is n15, and the refractive index of the sixteenth lens 16 is n16, and the following conditions are satisfied: 1.6 < n1 < 1.7, 1.6 < n2 < 1.7, 1.45 < n3 < 1.55, 1.45 < n4 < 1.55, 1.45 < n5 < 1.55, 1.45 < n6 < 1.55, 1.6 < n7 < 1.7, 1.6 < n8 < 1.7, 1.6 < n9 < 1.7, 1.6 < n10 < 1.7, 1.45 < n11 < 1.55, 1.45 < n12 < 1.55, 1.45 < n13 < 1.55, 1.45 < n14 < 1.55, 1.6 < n15 < 1.7, 1.6 < n16 < 1.7. By controlling the value range of the refractive index of each lens, the refraction angle and path of light can be controlled more precisely, so as to ensure that the light converges to the correct position, improve the clarity and reduce the distortion, and improve the lithography effect.

[0077] It can be understood that during the lithography process, the objective lens needs to be precisely focused on the wafer surface to ensure that the pattern can be accurately transferred to the photoresist. If the range of the radius of curvature is too large or too small, it may lead to inaccurate focusing, thus affecting the quality and yield of the final product. For example, if the radius of curvature is too small, it may increase spherical aberration; if the radius of curvature is too large, the required high resolution may not be achieved. Therefore, in an embodiment of the present invention, the radius of curvature of the object side of the first lens 1 is R2, the radius of curvature of the image side is R3, the radius of curvature of the object side of the second lens 2 is R4, the radius of curvature of the image side is R5, the radius of curvature of the object side of the third lens 3 is R6, the radius of curvature of the image side is R7, the radius of curvature of the object side of the fourth lens 4 is R8, the radius of curvature of the image side is R9, the radius of curvature of the object side of the fifth lens 5 is R10, the radius of curvature of the image side is R11, the radius of curvature of the object side of the sixth lens 6 is R12, the radius of curvature of the image side is R13, the radius of curvature of the object side of the seventh lens 7 is R14, the radius of curvature of the image side is R15, the radius of curvature of the object side of the eighth lens 8 is R16, the radius of curvature of the image side is R17, the radius of curvature of the object side of the ninth lens 9 is R19, the radius of curvature of the image side is R20, the radius of curvature of the object side of the tenth lens 10 is R21, the radius of curvature of the image side is R22, the radius of curvature of the object side of the eleventh lens 11 is R23, the radius of curvature of the image side is R24, the radius of curvature of the object side of the twelfth lens 12 is R25, the radius of curvature of the image side is R26, the radius of curvature of the object side of the thirteenth lens 13 is R27, the radius of curvature of the image side is R28, the radius of curvature of the object side of the fourteenth lens 14 is R29, the radius of curvature of the image side is R30, the radius of curvature of the object side of the fifteenth lens 15 is R31, the radius of curvature of the image side is R32, the radius of curvature of the object side of the sixteenth lens 16 is R33, the radius of curvature of the image side is R34, and it satisfies: 235mm < R2 < -225mm, 395mm < R3 < 405mm, -175mm < R4 < -160mm, -145mm < R5 < -135mm, -710mm < R6 < -695mm, -150mm < R7 < -140mm, 225mm < R8 < 235mm, -1450mm < R9 < -1350mm, 165mm < R10 < 175mm, 3650mm < R11 < 3720mm, 135mm < R12 < 145mm, 270mm < R13 < 280mm, 935mm < R14 < 950mm, 100mm < R15 < 110mm, 100mm < R16 < 110mm, 80mm < R17 < 90mm, -90mm < R19 < -80mm, -110mm < R20 < -100mm,-110 mm < R21 < -100 mm, -950 mm < R22 < -935 mm, -280 mm < R23 < -270 mm, -145 mm < R24 < -135 mm, -3720 mm < R25 < -3650 mm, -175 mm < R26 < -165 mm, 1350 mm < R27 < 1450 mm, -235 mm < R28 < -225 mm, 140 mm < R29 < 150 mm, 695 mm < R30 < 710 mm, 135 mm < R31 < 145 mm, 160 mm < R32 < 175 mm, -405 mm < R33 < -395 mm, 225 mm < R34 < 235 mm; By restricting the range of the radius of curvature, spherical aberration can be reduced, the lithography quality can be improved, and an appropriate range of the radius of curvature helps to control chromatic aberration, ensuring that light rays of different wavelengths are focused at the same position and thus enhancing the lithography effect.

[0078] In addition, it can be understood that the objective lens needs to be precisely focused on the wafer surface to ensure that the pattern can be accurately transferred onto the photoresist. If the range of the lens thickness is not appropriate, it may lead to inaccurate focusing, thereby affecting the quality and yield of the final product. For example, if the lens is too thick, chromatic aberration may increase; if the lens is too thin, the required high resolution may not be achieved. Therefore, in an embodiment of the present utility model, the thickness of the first lens 1 is G1, the thickness of the second lens 2 is G2, the thickness of the third lens 3 is G3, the thickness of the fourth lens 4 is G4, the thickness of the fifth lens 5 is G5, the thickness of the sixth lens 6 is G6, the thickness of the seventh lens 7 is G7, the thickness of the eighth lens 8 is G8, the thickness of the ninth lens 9 is G9, the thickness of the tenth lens 10 is G10, the thickness of the eleventh lens 11 is G11, the thickness of the twelfth lens 12 is G12, the thickness of the thirteenth lens 13 is G13, the thickness of the fourteenth lens 14 is G14, the thickness of the fifteenth lens 15 is G15, the thickness of the sixteenth lens 16 is G16, and the following conditions are satisfied: 7 mm < G1 < 8 mm, 34 mm < G2 < 36 mm, 28 mm < G3 < 30 mm, 23 mm < G4 < 30 mm, 25 mm < G5 < 30 mm, 15 mm < G6 < 20 mm, 5 mm < G7 < 8 mm, 6 mm < G8 < 8 mm, 6 mm < G9 < 8 mm, 5 mm < G10 < 8 mm, 15 mm < G11 < 20 mm, 25 mm < G12 < 30 mm, 23 mm < G13 < 30 mm, 28 mm < G14 < 30 mm, 34 mm < G15 < 36 mm, 7 mm < G16 < 8 mm; By restricting the thickness of each lens, better matching with other lithography machine components (such as the mask stage, wafer stage, etc.) can be achieved, ensuring the coordinated operation of the entire system.

[0079] Specifically, in an embodiment of the present utility model, the parameters of the fixed-focus projection optical system 100 are shown in Table 1 below.

[0080]

[0081]

[0082] Among them, the object side of the first lens 1 is numbered S2, and the image side is numbered S3; the object side of the second lens 2 is numbered S4, and the image side is numbered S5; the object side of the third lens 3 is numbered S6, and the image side is numbered S7; the object side of the fourth lens 4 is numbered S8, and the image side is numbered S9; the object side of the fifth lens 5 is numbered S10, and the image side is numbered S11; the object side of the sixth lens 6 is numbered S12, and the image side is numbered S13; the object side of the seventh lens 7 is numbered S14, and the image side is numbered S15; the object side of the eighth lens 8 is numbered S16, and the image side is numbered S17; the object side of the ninth lens 9 is numbered S19, and the image side is numbered S20; the object side of the tenth lens 10 is numbered S21, and the image side is numbered S22; the object side of the eleventh lens 11 is numbered S23, and the image side is numbered S24; the object side of the twelfth lens 12 is numbered S25, and the image side is numbered S26; the object side of the thirteenth lens 13 is numbered S27, and the image side is numbered S28; the object side of the fourteenth lens 14 is numbered S29, and the image side is numbered S30; the object side of the fifteenth lens 15 is numbered S31, and the image side is numbered S32; the object side of the sixteenth lens 16 is numbered S33, and the image side is numbered S34.

[0083] Specifically, in this embodiment, Figure 2 the MTF curve graph of the example at 294 lp / mm, Figure 3 is the TFM curve graph of the example at 294 lp / mm, Figure 4 is the spot diagram of the example, Figure 5 is the field curvature / distortion schematic diagram of the example. It can be seen from Figures 2 - 5 that the fixed-focus lens provided in this embodiment has good imaging ability.

[0084] The above description is only an exemplary embodiment of the present utility model, and does not limit the patent scope of the present utility model. Any equivalent structural transformation made under the technical concept of the present utility model by using the content of the specification and drawings of the present utility model, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present utility model.

Claims

1. A fixed-focus optical system, characterized in that: The fixed-focus optical system has an object side and an image side which are arranged opposite to each other along the optical axis direction, and the fixed-focus optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a stop, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, a fifteenth lens, and a sixteenth lens which are arranged in sequence from the object side to the image side; wherein the first lens has negative optical power; The second lens has positive optical power; The third lens has positive optical power; The fourth lens has positive refractive power; The fifth lens has positive optical power; The sixth lens has positive optical power; The seventh lens has negative optical power; The eighth lens has negative optical power; The ninth lens has negative optical power; The tenth lens has negative optical power; The eleventh lens has positive refractive power; The twelfth lens has positive optical power; The thirteenth lens has positive refractive power; The fourteenth lens has positive refractive power; The fifteenth lens has positive refractive power; The sixteenth lens has negative refractive power.

2. The fixed-focus optical system according to claim 1, wherein: The focal length of the fixed-focus optical system is f, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, the focal length of the eighth lens is f8, the focal length of the ninth lens is f9, the focal length of the tenth lens is f10, the focal length of the eleventh lens is f11, the focal length of the twelfth lens is f12, the focal length of the thirteenth lens is f13, the focal length of the fourteenth lens is f14, the focal length of the fifteenth lens is f15, and the focal length of the sixteenth lens is f16, and the following relationship is satisfied: 0.1<|f1 / f|<0.2, 0.5<|f2 / f|<0.6, 0.2<|f3 / f|<0.3, 0.2<|f4 / f|<0.3, 0 .2<|f5 / f|<0.3, 0.3<|f6 / f|<0.4, 0.1<|f7 / f|<0.2, 0.4<|f8 / f|<0.5, 0.4 <|f9 / f|<0.5, 0.1<|f10 / f|<0.2, 0.3<|f11 / f|<0.4, 0.2<|f12 / f|<0.3, 0. 2<|f13 / f|<0.3, 0.2<|f14 / f|<0.3, 0.5<|f15 / f|<0.6, 0.1<|f16 / f|<0.

2.

3. The fixed-focus optical system according to claim 1, wherein: The object side surface of the first lens is concave, and the image side surface is concave; The object side surface of the second lens is concave, and the image side surface is convex; The object side surface of the third lens is concave, and the image side surface is convex; The object side surface of the fourth lens is convex, and the image side surface is convex; The object side surface of the fifth lens is convex, and the image side surface is concave; The object side surface of the sixth lens is convex, and the image side surface is concave; The object side surface of the seventh lens is convex, and the image side surface is concave; The object side surface of the eighth lens is convex, and the image side surface is concave; The object side surface of the ninth lens is a concave surface, and the image side surface is a convex surface; The object side surface of the tenth lens is concave, and the image side surface is convex; The object side surface of the eleventh lens is a concave surface, and the image side surface is a convex surface; The object side surface of the twelfth lens is a concave surface, and the image side surface is a convex surface; The object side surface of the thirteenth lens is convex, and the image side surface is convex; The object side surface of the fourteenth lens is convex, and the image side surface is concave; The object side surface of the fifteenth lens is convex, and the image side surface is concave; The object side surface of the sixteenth lens is a concave surface, and the image side surface is a concave surface.

4. The fixed-focus optical system according to claim 1, wherein: The fixed-focus optical system includes two lens groups which are respectively located on both sides of the aperture along the optical axis and are symmetrically arranged, wherein one of the lens groups is composed of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens, and the other lens group is composed of the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens, the fourteenth lens, the fifteenth lens, and the sixteenth lens.

5. The fixed-focus optical system according to claim 1, wherein: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens, the fourteenth lens, the fifteenth lens and the sixteenth lens are all configured as glass spherical lenses.

6. The fixed-focus optical system according to claim 1, wherein: The focal length of the fixed-focus optical system is f, the total optical length of the fixed-focus optical system is TTL, and the following conditions are met: 0.5 <TTL / f<0.6,800mm<TTL<900mm。 7. The fixed-focus optical system according to claim 1, wherein: The image side numerical aperture of the fixed-focus optical system is NA, the aperture value is F, and the following conditions are met: NA≥0.15,3.3≤F<4.

8. The fixed-focus optical system according to claim 1, wherein: The refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, the refractive index of the seventh lens is n7, the refractive index of the eighth lens is n8, the refractive index of the ninth lens is n9, the refractive index of the tenth lens is n10, the refractive index of the eleventh lens is n11, the refractive index of the twelfth lens is n12, the refractive index of the thirteenth lens is n13, the refractive index of the fourteenth lens is n14, the refractive index of the fifteenth lens is n15, and the refractive index of the sixteenth lens is n16, and the following conditions are satisfied: 1.6 <n1<1.7,1.6<n2<1.7,1.45<n3<1.55,1.45<n4<1.55,1.45<n5<1.55,1.45<n6<1.55,1.6<n7<1.7,1.6<n8<1.7,1.6<n9<1.7,1.6<n10<1.7,1.45<n11<1.55,1.45<n12<1.55,1.45<n13<1.55,1.45<n14<1.55,1.6<n15<1.7,1.6<n16<1.7。 9. The fixed-focus optical system according to claim 1, wherein: The object side surface of the first lens has a curvature radius of R2, and the image side surface has a curvature radius of R3. The object side surface of the second lens has a curvature radius of R4, and the image side surface has a curvature radius of R5. The object side surface of the third lens has a curvature radius of R6, and the image side surface has a curvature radius of R7. The object side surface of the fourth lens has a curvature radius of R8, and the image side surface has a curvature radius of R9. The object side surface of the fifth lens has a curvature radius of R10, and the image side surface has a curvature radius of R11. The object side surface of the sixth lens has a curvature radius of R12, and the image side surface has a curvature radius of R13. The object side surface of the seventh lens has a curvature radius of R14, and the image side surface has a curvature radius of R15. The object side surface of the eighth lens has a curvature radius of R16, and the image side surface has a curvature radius of R17. The radius of curvature of the object side surface is R19, and the radius of curvature of the image side surface is R20. The radius of curvature of the object side surface of the tenth lens is R21, and the radius of curvature of the image side surface is R22. The radius of curvature of the object side surface of the eleventh lens is R23, and the radius of curvature of the image side surface is R24. The radius of curvature of the object side surface of the twelfth lens is R25, and the radius of curvature of the image side surface is R26. The radius of curvature of the object side surface of the thirteenth lens is R27, and the radius of curvature of the image side surface is R28. The radius of curvature of the object side surface of the fourteenth lens is R29, and the radius of curvature of the image side surface is R30. The radius of curvature of the object side surface of the fifteenth lens is R31, and the radius of curvature of the image side surface is R32. The radius of curvature of the object side surface of the sixteenth lens is R33, and the radius of curvature of the image side surface is R34, and the following conditions are satisfied: 235mm <R2<-225mm,395mm<R3<405mm,-175mm<R4<-160mm,-145mm<R5<-135mm,-710mm<R6<-695mm,-150mm<R7<-140mm,225mm<R8<235mm,-1450mm<R9<-1350mm,165mm<R10<175mm,3650mm<R11<3720mm,135mm<R12<145mm,270mm<R13<280mm,935mm<R14<950mm,100mm<R15<110mm,100mm<R16<110mm,80mm<R17<90mm,-90mm<R19<-80mm,-110mm<R20<-100mm,-110mm<R21<-100mm,-950mm<R22<-935mm,-280mm<R23<-270mm,-145mm<R24<-135mm,-3720mm<R25<-3650mm,-175mm<R26<-165mm,1350mm<R27<1450mm,-235mm<R28<-225mm,140mm<R29<150mm,695mm<R30<710mm,135mm<R31<145mm,160mm<R32<175mm,-405mm<R33<-395mm,225mm<R34<235mm。 10. The fixed-focus optical system according to claim 1, wherein: The thickness of the first lens is G1, the thickness of the second lens is G2, the thickness of the third lens is G3, the thickness of the fourth lens is G4, the thickness of the fifth lens is G5, the thickness of the sixth lens is G6, the thickness of the seventh lens is G7, the thickness of the eighth lens is G8, the thickness of the ninth lens is G9, the thickness of the tenth lens is G10, the thickness of the eleventh lens is G11, the thickness of the twelfth lens is G12, the thickness of the thirteenth lens is G13, the thickness of the fourteenth lens is G14, the thickness of the fifteenth lens is G15, and the thickness of the sixteenth lens is G16, and the following conditions are satisfied: 7mm <G1<8mm,34mm<G2<36mm,28mm<G3<30mm,23mm<G4<30mm,25mm<G5<30mm,15mm<G6<20mm,5mm<G7<8mm,6mm<G8<8mm,6mm<G9<8mm,5mm<G10<8mm,15mm<G11<20mm,25mm<G12<30mm,23mm<G13<30mm,28mm<G14<30mm,34mm<G15<36mm,7mm<G16<8mm。

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