Photoetching lens and photoetching machine

Abstract

The utility model relates to a photoetching lens and a photoetching machine, which comprise a first lens group and a first reflecting mirror which are sequentially arranged along the direction of a first optical axis, and a second reflecting mirror, a second lens group and a third lens group which are sequentially arranged along the direction of a second optical axis, and after being reflected by the first reflecting mirror to pass through the second lens group in the forward direction, the light is reflected by the second reflecting mirror to pass through the second lens group in the reverse direction, and then passes through the third lens group to converge to an imaging surface. The structure of the photoetching lens has excellent imaging performance, a larger view field can be realized, and large-area photoetching pattern processing can be directly realized, so that the problem that the view field of the existing photoetching lens is small is solved; besides, a reflective structure is adopted, so that the light beam passes through the second lens group twice in the forward and reverse directions, the number of lenses is reduced by half while the transmission distance of the light beam is ensured, and therefore, the volume of the photoetching lens is effectively reduced, and the cost of the photoetching lens is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of lithography, in particular to a lithography lens and a lithography machine for the ultraviolet band. Background Art

[0002] The lithography lens is a very important imaging element in the lithography machine, and it is one of the main factors affecting the lithography line width and lithography area. With the development of the times, the requirements for lithography products are getting higher and higher, and the lithography area is also increasing. However, the current lens-type lithography lens has a small field of view, and it is impossible to directly realize the processing of large-area lithography patterns. It is necessary to perform multiple small-area lithographies and then move and splice them to form a large-area lithography pattern. Due to the splicing error in the splicing processing method, the accuracy of the lithography pattern will be seriously affected. In addition, the number of lenses of the current transmissive lithography lens is generally more than ten, resulting in problems of large volume and high cost of the lithography lens. Summary of the Utility Model

[0003] The utility model provides a lithography lens, which can directly realize the processing of large-area lithography patterns, and at the same time reduce the number of lenses and the volume of the lithography lens.

[0004] To achieve the above object, the utility model provides a lithography lens applied to the ultraviolet band, which is characterized in that it includes a first lens group and a first mirror arranged in sequence along the first optical axis direction, and a second mirror, a second lens group and a third lens group arranged in sequence along the second optical axis direction, wherein the first optical axis direction and the second optical axis direction are perpendicular; the first mirror is arranged between the second lens group and the third lens group and forms a 45° angle with the first optical axis direction, and the second mirror is perpendicular to the second optical axis direction; the light beam emitted from the object plane passes through the first lens group, is reflected by the first mirror and then passes through the second lens group in the forward direction, is reflected by the second mirror and then passes through the second lens group in the reverse direction, and then passes through the third lens group to converge on the image plane.

[0005] As a further improvement of the utility model, the lithography lens further includes a diaphragm concentrically arranged on the second mirror.

[0006] As a further improvement of the utility model, the first lens group includes a first lens with positive optical power, the side of the first lens close to the object plane is concave, and the side far from the object plane is convex; the third lens group includes a sixth lens with positive optical power, the side of the sixth lens close to the image plane is concave, and the side far from the image plane is convex.

[0007] As a further improvement of the utility model, the first lens is a meniscus lens with the concave surface facing the object plane, and the sixth lens is a meniscus lens with the concave surface facing the image plane.

[0008] As a further improvement of the present utility model, the first lens and the sixth lens are each half of the same complete spherical lens.

[0009] As a further improvement of the present utility model, the second lens group includes a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence. The second lens is disposed on the side close to the first reflector, and the fifth lens is disposed on the side close to the second reflector. The second lens, the third lens, and the fourth lens all have positive optical powers, and the fifth lens has a negative optical power.

[0010] As a further improvement of the present utility model, the focal length f1 of the first lens has a value range of 4150 mm < f1 < 4200 mm, the focal length f2 of the second lens has a value range of 1100 mm < f2 < 1150 mm, the focal length f3 of the third lens has a value range of 700 mm < f3 < 750 mm, the focal length f4 of the fourth lens has a value range of 850 mm < f4 < 900 mm, the focal length f5 of the fifth lens has a value range of -300 mm < f5 < -250 mm, and the focal length f6 of the sixth lens has a value range of 4150 mm < f6 < 4200 mm.

[0011] As a further improvement of the present utility model, the second lens is a biconvex lens, and the third lens, the fourth lens, and the fifth lens are all meniscus lenses with their concave surfaces facing the aperture stop.

[0012] As a further improvement of the present utility model, the first reflector and the second reflector are both plane reflectors.

[0013] The present utility model further provides a lithography machine, including the lithography lens according to any one of the above technical solutions. The lithography lens is an equal-magnification imaging lens, and the wavelength range value applied by the lithography lens is 400 nm ≤ λ ≤ 410 nm.

[0014] Compared with the prior art, the structure of the lithography lens of the present utility model has excellent imaging performance, can achieve a large field of view, and can directly realize large-area lithography pattern processing, thereby solving the problem of the small field of view of the existing lithography lens and avoiding the problem of splicing error affecting the pattern accuracy. In addition, the lithography lens of the present utility model adopts a reflective structure, enabling the light beam to pass through the second lens group twice in the forward and reverse directions, reducing the number of lenses by half while ensuring the light beam transmission distance, thereby effectively reducing the volume of the lithography lens and lowering the cost of the lithography lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of the lithography lens in a specific embodiment of the present application;

[0016] Figure 2It is the modulation transfer function graph of the lithography lens in the specific embodiment of the present application;

[0017] Figure 3 It is the spot diagram of the lithography lens in the specific embodiment of the present application;

[0018] Figure 4 It is the distortion graph of the lithography lens in the specific embodiment of the present application.

[0019] Reference numerals:

[0020] 1. First lens group; 11. First lens; 2. First mirror; 3. Second mirror; 4. Aperture; 5. Second lens group; 51. Second lens; 52. Third lens; 53. Fourth lens; 54. Fifth lens; 6. Third lens group; 61. Sixth lens. Detailed implementation manners

[0021] To make the objectives, technical solutions, and advantages of the present utility model clearer and more understandable, the present utility model will be described below through specific embodiments shown in the drawings.

[0022] A lithography lens, which is applied in the ultraviolet band, includes a first lens group 1 and a first mirror 2 arranged in sequence along the first optical axis direction, and a second mirror 3, a second lens group 5, and a third lens group 6 arranged in sequence along the second optical axis direction. The first optical axis direction and the second optical axis direction are perpendicular. The first mirror 2 forms an angle of 45 degrees with the first optical axis direction, and the first mirror 2 is disposed between the second lens group 5 and the third lens group 6. The second mirror 3 is perpendicular to the second optical axis direction.

[0023] The light beam emitted from the object surface passes through the first lens group 1, is reflected by the first mirror 2 to pass forward through the second lens group 5, is reflected by the second mirror 3 to pass backward through the second lens group 5, and then passes through the third lens group 6 to converge on the image surface.

[0024] In the lithography lens, the main beam direction of the object surface field of view is the first optical axis direction, and the main beam direction of the image surface field of view is the second optical axis direction. It is defined that the first optical axis direction is represented by y, the second optical axis direction is represented by x, and the second optical axis direction x and the first optical axis direction y are perpendicular to each other.

[0025] In the lithography lens of the present utility model, after the light beam emitted from the object plane is refracted by the first lens group 1 along the first optical axis direction, the direction of the light beam is first changed by the first reflector 2, so that the light beam enters the second lens group 5 arranged in the second optical axis direction in the forward direction, and is refracted by the second lens group 5 to the second reflector 3. Then, the light beam is reflected back to the second lens group 5 by the second reflector 3, and the light beam after passing through the second lens group 5 in the reverse direction enters the third lens group 6, and then converges to the imaging plane through the third lens group 6. It can be understood that the refraction paths of the light beam entering the second lens group 5 from the second reflector 3 and the light beam entering the second lens group 5 from the first reflector 2 are opposite. It can be understood that the forward and reverse directions referred to in the present invention mean that the directions of the light beam passing through the second lens group 5 twice are opposite, and the specific direction settings of the forward and reverse directions and the settings of the lenses in the second lens group 5 can be adjusted according to the actual situation.

[0026] The lithography lens in the present utility model adopts a reflective structure, enabling the light beam to pass through the second lens group 5 in the forward and reverse directions twice, reducing the number of lens elements in the lithography lens by half while ensuring the light beam transmission distance, thereby effectively reducing the volume of the lithography lens and lowering the cost of the lithography lens. At the same time, the lithography lens can achieve a large field of view, is suitable for large-area lithography scenarios, and has excellent imaging performance.

[0027] Specifically, the lithography lens is an equal-magnification imaging lens, the wavelength range value applied by the lithography lens is 400nm ≤ λ ≤ 410nm, and the maximum field of view of the object plane can reach 200mm × 100mm.

[0028] Both the first reflector 2 and the second reflector 3 are plane reflectors. The 45° angle between the first reflector 2 and the first optical axis can be understood as the minimum angle between the reflecting surface of the first reflector 2 and the first optical axis. In one embodiment, as Figure 1 shown in the structural schematic diagram of the lithography lens, if the first optical axis direction is the vertical direction and the second optical axis direction is the horizontal direction, then the first reflector 2 forms a 45° angle with the first optical axis direction. The light beam transmitted along the first optical axis direction is changed to be transmitted along the second optical axis direction through the first reflector 2, creating a relatively large distance between the object plane and the image plane and leaving sufficient mechanical space. It can be understood that the first reflector 2 of the lithography lens in the present utility model is not limited to Figure 1 the placement method in Figure 1 In other embodiments, the first reflector 2 can be mirror-symmetrically arranged with the first reflector 2 in

[0029] In one embodiment, the lithography lens further includes a diaphragm concentrically arranged with the second reflector 3. The center of the diaphragm 4 coincides with the center of the second reflector 3, and the diaphragm 4 plays a role in restricting the light beam.

[0030] The first lens group 1, the second lens group 5, and the third lens group 6 in the lithographic lens will be elaborated in detail below.

[0031] The first lens group 1 includes a first lens 11 with a positive focal power. One side of the first lens 11 close to the object surface is concave, and the side away from the object surface is convex.

[0032] The third lens group 6 includes a sixth lens 61 with a positive focal power. One side of the sixth lens 61 close to the image surface is concave, and the side away from the image surface is convex.

[0033] In one embodiment, the first lens 11 is a meniscus lens with the concave surface facing the object surface, and the third lens group 6 includes the sixth lens 61, which is a meniscus lens with the concave surface facing the image surface. The light beam emitted from the object surface is diverged by the first lens 11 to the first mirror 2, and the light beam emitted from the second lens group 5 is converged to the image surface by the sixth lens 61.

[0034] In another embodiment, the first lens 11 and the sixth lens 61 are each half of the same complete spherical lens. It can be understood that both the first lens 11 and the sixth lens 61 are half spherical lenses, and the first lens 11 and the sixth lens 61 can be spliced into a complete spherical lens, thereby reducing the volume of the first lens group 1 and the third lens group 6, being more conducive to the miniaturization of the lithographic lens, and at the same time saving the cost of the lithographic lens.

[0035] The second lens group 5 includes a second lens 51, a third lens 52, a fourth lens 53, and a fifth lens 54 arranged in sequence. The second lens 51 is arranged on the side close to the first mirror 2, the fifth lens 54 is arranged on the side close to the second mirror 3, the second lens 51, the third lens 52, and the fourth lens 53 all have positive focal powers, and the fifth lens 54 has a negative focal power.

[0036] Furthermore, the value range of the focal length f1 of the first lens 11 is 4150 mm < f1 < 4200 mm, the value range of the focal length f2 of the second lens 51 is 1100 mm < f2 < 1150 mm, the value range of the focal length f3 of the third lens 52 is 700 mm < f3 < 750 mm, the value range of the focal length f4 of the fourth lens 53 is 850 mm < f4 < 900 mm, the value range of the focal length f5 of the fifth lens 54 is -300 mm < f5 < -250 mm, and the value range of the focal length f6 of the sixth lens 61 is 4150 mm < f6 < 4200 mm. By combining positive lenses and negative lenses and coordinating the focal lengths of each lens, the lithographic lens can have a high imaging quality.

[0037] In one embodiment, as Figure 1As shown in the structural schematic diagram of the lithography lens, the second lens 51 is a biconvex lens, and the third lens 52, the fourth lens 53, and the fifth lens 54 are all meniscus lenses with their concave surfaces facing the aperture stop 4. Figure 1 The straight lines in Figure 1 are the transmission paths of the light beams inside the lithography lens. As

[0038] shown, the light beams emitted from the object surface diverge along the first optical axis direction through the first lens group 1, and then the direction of the light beams is changed by the first mirror 2, so that the light beams enter the second lens group 5 arranged in the second optical axis direction. After the light beams reflected by the first mirror 2 enter the second lens group 5, the light beams sequentially pass through the second lens 51, the third lens 52, the fourth lens 53, and the fifth lens 54. The second lens 51, the third lens 52, the fourth lens 53, and the fifth lens 54 sequentially adjust the transmission direction of the light beams, so that the light beams converge to the second mirror 3 and are reflected back to the second lens group 5 by the second mirror 3. At this time, the light beams sequentially pass through the fifth lens 54, the fourth lens 53, the third lens 52, and the second lens 51, and the fifth lens 54, the fourth lens 53, the third lens 52, and the second lens 51 sequentially adjust the transmission direction of the light beams, so that the light beams enter the sixth lens 61 and are converged to the image surface by the sixth lens 61.

[0038] The lithography lens will be described below through a specific embodiment.

[0039] The lithography lens of this embodiment includes a first lens 11 and a first mirror 2 arranged along the first optical axis direction, a second mirror 3 arranged along the second optical axis direction, an aperture stop 4 arranged on the second mirror 3 and coinciding with the center of the second mirror 3, a second lens 51, a third lens 52, a fourth lens 53, a fifth lens 54, and a sixth lens 61. Among them, the second lens 51, the third lens 52, the fourth lens 53, and the fifth lens 54 form the second lens group 5. The first lens 11 is a meniscus lens with its concave surface facing the object surface. The second lens 51 is a biconvex lens. The third lens 52, the fourth lens 53, and the fifth lens 54 are all meniscus lenses with their concave surfaces facing the aperture stop 4. The sixth lens 61 is a meniscus lens with its concave surface facing the image surface. The first lens 11, the second lens 51, the third lens 52, the fourth lens 53, and the sixth lens 61 all have positive optical powers, and the fifth lens 54 has a negative optical power. The first lens 11 and the sixth lens 61 are each half of the same complete spherical lens.

[0040] The wavelength range value applied by the lithography lens is 400nm ≤ λ ≤ 410nm.

[0041] The specific parameters of each lens are as follows in the table:

[0042]

[0043]

[0044] In the table, R is the radius of curvature of the surface of each optical element, TH is the central thickness of each optical element, Nd is the refractive index of each optical element, and Vd is the Abbe number of each optical element.

[0045] In the table, the first lens, the second lens, the third lens, the fourth lens, and the sixth lens are all made of crown glass material (H-K9LGT_CDGM), and the fifth lens is made of flint glass material (F4GTI_CDGM). Setting the lenses in the lithography lens to glass materials of different materials can ensure that each lens in the lithography lens meets the requirements of optical imaging quality.

[0046] After configuring according to the above table, optical tests are carried out to obtain Figures 2 - 4 the test data.

[0047] Figure 2 is the modulation transfer function (MTF) graph of the lithography lens. From Figure 2 it can be seen that the MTF values of the lithography lens at each frequency are close to the diffraction limit, so that better imaging quality can be achieved.

[0048] Figure 3 is the spot diagram of the lithography lens. From Figure 3 it can be seen that the root mean square radius of the lithography lens at each field of view is within the Airy disk radius, and various aberrations of the lithography lens are better balanced.

[0049] Figure 4 is the distortion graph of the lithography lens. From Figure 4 it can be seen that the distortion correction of the optical system is within the range of 1*10 -5 mm. The distortion value of the lithography lens is small and the imaging quality is high.

[0050] The effective field of view of the object plane of the lithography lens can reach 218mm*108mm, and the numerical aperture is 0.046. The lithography lens is an equal magnification imaging and an inverted imaging.

[0051] The lithography lens of this embodiment can achieve a large field of view, can directly realize large-area lithography pattern processing, and avoid the problem of splicing errors affecting the pattern accuracy. Secondly, by adopting the combination of positive lenses and negative lenses, and then setting appropriate optical powers for each lens, the lithography lens can have high imaging quality. Furthermore, the lithography lens of the present invention adopts a reflective structure, enabling the light beam to pass through the second lens group twice in the forward and reverse directions, reducing the number of lenses while ensuring the light beam transmission distance, thereby effectively reducing the volume of the lithography lens and lowering the cost of the lithography lens.

[0052] The above-described embodiments merely represent several embodiments of the present utility model. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the utility model patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several variations and improvements can still be made, and these all fall within the protection scope of the present utility model.

Claims

1. A lithographic lens, applied in the ultraviolet band, characterized in that, It includes a first lens group and a first mirror arranged successively along a first optical axis direction, and a second mirror, a second lens group, and a third lens group arranged successively along a second optical axis direction, where the first optical axis direction and the second optical axis direction are perpendicular; The first mirror is arranged between the second lens group and the third lens group and forms a 45° angle with the first optical axis direction, and the second mirror is perpendicular to the second optical axis direction; the light beam emitted from the object surface passes through the first lens group, is reflected by the first mirror, then passes through the second lens group in the forward direction, is reflected by the second mirror, then passes through the second lens group in the reverse direction, and then passes through the third lens group to converge on the image surface.

2. The lithographic lens according to claim 1, characterized in that, The lithographic lens further includes a diaphragm concentrically arranged on the second mirror.

3. The lithographic lens according to claim 2, characterized in that, The first lens group includes a first lens with a positive focal power. The side of the first lens close to the object surface is concave, and the side away from the object surface is convex; the third lens group includes a sixth lens with a positive focal power. The side of the sixth lens close to the image surface is concave, and the side away from the image surface is convex.

4. The lithographic lens according to claim 3, characterized in that, The first lens is a meniscus lens with the concave surface facing the object surface, and the sixth lens is a meniscus lens with the concave surface facing the image surface.

5. The lithographic lens according to claim 3, characterized in that, The first lens and the sixth lens are each half of the same complete spherical lens.

6. The lithographic lens according to claim 3, wherein The second lens group includes a second lens, a third lens, a fourth lens, and a fifth lens arranged successively. The second lens is arranged on the side close to the first mirror, and the fifth lens is arranged on the side close to the second mirror. The second lens, the third lens, and the fourth lens all have positive focal powers, and the fifth lens has a negative focal power.

7. The lithographic lens according to claim 6, wherein The value range of the focal length f1 of the first lens is 4150 mm < f1 < 4200 mm, the value range of the focal length f2 of the second lens is 1100 mm < f2 < 1150 mm, the value range of the focal length f3 of the third lens is 700 mm < f3 < 750 mm, the value range of the focal length f4 of the fourth lens is 850 mm < f4 < 900 mm, the value range of the focal length f5 of the fifth lens is -300 mm < f5 < -250 mm, and the value range of the focal length f6 of the sixth lens is 4150 mm < f6 < 4200 mm.

8. The lithographic lens according to claim 6, wherein The second lens is a biconvex lens, and the third lens, the fourth lens, and the fifth lens are all meniscus lenses with the concave surface facing the diaphragm.

9. The lithographic lens according to claim 1, wherein The first mirror and the second mirror are both plane mirrors.

10. A lithography machine, characterized in that, It includes the lithographic lens according to any one of claims 1-9. The lithographic lens is an equal magnification imaging lens, and the wavelength range value applied by the lithographic lens is 400 nm ≤ λ ≤ 410 nm.

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