A deep ultraviolet infinity imaging detection objective

Abstract

This invention proposes a deep ultraviolet infinity imaging detection objective lens, belonging to the field of optical technology. It solves the problem of the difficulty in detecting minute defects in semiconductor devices. The objective lens includes a first lens group, an aperture, a second lens group, and a third lens group arranged sequentially along the optical axis from the object plane. The first lens group has positive optical power and includes a first meniscus lens, a second meniscus lens, a third meniscus lens, a fourth meniscus lens, a fifth meniscus lens, and a sixth meniscus lens. The second lens group has positive optical power and includes a seventh meniscus lens, an eighth meniscus lens, a ninth meniscus lens, a first biconvex lens, and a second biconvex lens. The third lens group has negative optical power and includes a first biconcave lens, a tenth meniscus lens, a second biconcave lens, and an eleventh meniscus lens. Finally, the light emitted from the third lens group is parallel light. It can achieve different magnifications, is applicable to the very short wavelength deep ultraviolet band, has a larger numerical aperture, and provides higher resolution.

Description

Technical Field

[0001] This invention belongs to the field of optical technology, and in particular relates to a deep ultraviolet infinity imaging detection objective. Background Technology

[0002] In the semiconductor industry, defect detection and screening are crucial for improving the yield of semiconductor devices. As semiconductor devices continue to shrink, their detection resolution also needs to be gradually improved. It is well known that the resolution of an optical microscopy system can be calculated using 0.61λ / NA, so improving system resolution can be achieved by shortening the wavelength and increasing the numerical aperture. To increase the resolution of the detection system, wavelengths are gradually moving towards shorter wavelengths in the ultraviolet range; on the other hand, increasing the numerical aperture of the optical system increases the optical resolution of the system.

[0003] Therefore, in order to reduce the impact of minute defects on the performance and reliability of semiconductor devices such as chips, there is an urgent need for a microscopic inspection objective with a shorter wavelength and a larger numerical aperture. Summary of the Invention

[0004] In view of this, in order to solve the above problems, the present invention proposes a deep ultraviolet infinity imaging detection objective.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A deep ultraviolet infinity imaging detection objective includes: a first lens group, an aperture, a second lens group, and a third lens group arranged sequentially from the object surface along the optical axis. Light passes through the first lens group, the aperture, the second lens group, and the third lens group in sequence, and the light emitted from the third lens group is parallel light.

[0007] The first lens group has positive optical power and includes a first meniscus lens, a second meniscus lens, a third meniscus lens, a fourth meniscus lens, a fifth meniscus lens and a sixth meniscus lens arranged sequentially from the object plane to the image plane.

[0008] The second lens group has positive optical power and includes a seventh meniscus lens, an eighth meniscus lens, a ninth meniscus lens, a first biconvex lens, and a second biconvex lens arranged sequentially from the object plane to the image plane.

[0009] The third lens group has negative optical power and includes a first biconcave lens, a tenth meniscus lens, a second biconcave lens, and an eleventh meniscus lens arranged sequentially from the object plane to the image plane.

[0010] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging detection objective lens, the first meniscus lens, the second meniscus lens, the third meniscus lens, the fourth meniscus lens, and the fifth meniscus lens in the first lens group have the same meniscus direction, and their convex sides all face the image plane direction. The meniscus directions of the fifth meniscus lens and the sixth meniscus lens are opposite, and they have positive optical power.

[0011] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging detection objective, the aperture stop is an aperture stop.

[0012] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging detection objective lens, the seventh and ninth meniscus lenses in the second lens group have the same meniscus direction and their convex sides face the object surface. The seventh and eighth meniscus lenses have opposite meniscus directions and negative optical power. The first and second biconvex lenses have positive optical power.

[0013] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging detection objective, the first biconcave lens has negative spherical aberration, which is used to correct the overall spherical aberration of the deep ultraviolet infinity imaging detection objective.

[0014] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging detection objective, the interval between the second lens group and the third lens group is adjustable, and axial defocus is compensated by adjusting the interval between the second lens group and the third lens group.

[0015] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging detection objective, the image-side working distance of the deep ultraviolet infinity imaging detection objective is infinity, and the object-side working distance is greater than 3.5 mm.

[0016] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging objective, the objective surface diameter of the deep ultraviolet infinity imaging objective is 1.2 mm.

[0017] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging objective, the numerical aperture of the deep ultraviolet infinity imaging objective is 0.85.

[0018] As a preferred embodiment of the aforementioned deep ultraviolet infinity imaging objective lens, the first lens group, the second lens group, and the third lens group all use the same ARF glass material.

[0019] Compared with existing technologies, the beneficial effects of the deep ultraviolet infinity imaging detection objective provided by this invention are:

[0020] 1. This invention provides a deep ultraviolet infinity imaging detection objective lens. Along the optical axis, from the object plane to the image plane, the deep ultraviolet infinity imaging detection objective lens has a first lens group, an aperture, a second lens group, and a third lens group arranged in sequence, totaling 15 lenses. It adopts a fully transmissive structure, and all lenses are spherical, which is convenient for processing and detection.

[0021] 2. This invention provides a deep ultraviolet infinity imaging objective lens. This objective lens employs infinity imaging, where light sequentially passes through a first lens group, an aperture stop, a second lens group, and a third lens group. The light exiting from the third lens group is parallel. This allows the deep ultraviolet infinity imaging objective lens to be used with tube lenses of different focal lengths to achieve different magnifications. By changing the focal length of the tube lenses, the system's magnification can be altered, making it suitable for different detection accuracies, different fields of view, and different cameras. Furthermore, since the light is parallel between the tube lens and the deep ultraviolet infinity imaging objective lens, adding other optical elements does not introduce additional optical path differences. It also eliminates the spacing error between the tube lens and the deep ultraviolet infinity imaging objective lens, reducing assembly and adjustment accuracy.

[0022] 3. This deep ultraviolet infinity imaging objective uses a very short wavelength deep ultraviolet band, suitable for the 193.368nm band, with a spectral width of up to 1pm. It has a large numerical aperture of 0.85 and a field of view of φ1.2mm. It offers higher resolution, calculated as 0.61λ / NA, due to the shorter wavelength. This solves the problem of difficult detection of minute defects in semiconductor devices, thereby improving the performance and reliability of semiconductor devices. Furthermore, this deep ultraviolet infinity imaging objective has a large imaging target surface, which is more conducive to improving detection speed. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 This is a schematic diagram of the structure of the deep ultraviolet infinity imaging detection objective lens provided in a specific embodiment of the present invention;

[0025] Figure 2 This is a modulation transfer function (MTF) curve of the deep ultraviolet infinity imaging detection objective provided in a specific embodiment of the present invention;

[0026] Figure 3 These are wavefront phase difference diagrams of different fields of view of the deep ultraviolet infinity imaging detection objective lens provided in a specific embodiment of the present invention;

[0027] Figure 4This is a field curvature diagram of the deep ultraviolet infinity imaging detection objective provided in a specific embodiment of the present invention;

[0028] Figure 5 This is a distortion diagram of the deep ultraviolet infinity imaging detection objective lens provided in a specific embodiment of the present invention.

[0029] In the picture:

[0030] 1. First lens group; 11. First meniscus lens; 12. Second meniscus lens; 13. Third meniscus lens; 14. Fourth meniscus lens; 15. Fifth meniscus lens; 16. Sixth meniscus lens;

[0031] 2. Second lens group; 21. Seventh meniscus lens; 22. Eighth meniscus lens; 23. Ninth meniscus lens; 24. First biconvex lens; 25. Second biconvex lens;

[0032] 3. Third lens group; 31. First biconcave lens; 32. Tenth meniscus lens; 33. Second biconcave lens; 34. Eleventh meniscus lens;

[0033] 4. Object surface;

[0034] 5. Aperture. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0036] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0039] See Figure 1-5 This invention provides a deep ultraviolet infinity imaging detection objective lens, comprising: a first lens group 1, an aperture 5, a second lens group 2, and a third lens group 3 arranged sequentially from the object plane 4 along the optical axis. Light passes through the first lens group 1, the aperture 5, the second lens group 2, and the third lens group 3 in sequence, and the light emitted from the third lens group 3 is parallel light. The first lens group 1 has positive optical power and includes a first meniscus lens 11, a second meniscus lens 12, a third meniscus lens 13, and a fourth meniscus lens arranged sequentially from the object plane 4 towards the image plane. 14. Fifth meniscus lens 15 and sixth meniscus lens 16; the second lens group 2 has positive optical power, and the second lens group 2 includes a seventh meniscus lens 21, an eighth meniscus lens 22, a ninth meniscus lens 23, a first biconvex lens 24 and a second biconvex lens 25 arranged sequentially from the object plane 4 towards the image plane; the third lens group 3 has negative optical power, and the third lens group 3 includes a first biconcave lens 31, a tenth meniscus lens 32, a second biconcave lens 33 and an eleventh meniscus lens 34 arranged sequentially from the object plane 4 towards the image plane.

[0040] like Figure 1 As shown, the deep ultraviolet infinity imaging objective lens has 15 lenses arranged sequentially along the optical axis from the object plane 4 to the image plane, including the first lens group 1, the aperture 5, the second lens group 2, and the third lens group 3. It adopts a fully transmissive structure, and all lenses are spherical, which facilitates processing and testing.

[0041] like Figure 2-5As shown, the deep ultraviolet infinity imaging detection objective lens has good performance.

[0042] This deep ultraviolet infinity imaging objective employs infinity imaging. Light passes sequentially through the first lens group 1, the aperture 5, the second lens group 2, and the third lens group 3. The light exiting from the third lens group 3 is parallel, allowing for different magnifications when used with tube lenses of varying focal lengths. Changing the focal length of the tube lens alters the system's magnification, making it suitable for different detection accuracies, fields of view, and cameras. Furthermore, the parallel light path between the tube lens and the deep ultraviolet infinity imaging objective eliminates the need for additional optical path differences when adding other optical components, thus eliminating spacing errors between the tube lens and the deep ultraviolet infinity imaging objective and reducing assembly accuracy.

[0043] This deep ultraviolet infinity imaging objective uses a very short wavelength in the deep ultraviolet band, suitable for the 193.368nm band, with a spectral width of up to 1pm. It features a large numerical aperture of 0.85 and a field of view of φ1.2mm. It offers higher resolution, calculated as 0.61λ / NA, due to the shorter wavelength. This addresses the difficulty in detecting minute defects in semiconductor devices, thereby improving their performance and reliability. Furthermore, the large imaging target area of ​​this deep ultraviolet infinity imaging objective further enhances detection speed.

[0044] In this embodiment, the first meniscus lens 11, the second meniscus lens 12, the third meniscus lens 13, the fourth meniscus lens 14 and the fifth meniscus lens 15 in the first lens group 1 have the same meniscus direction and their convex sides all face the image plane direction. The meniscus directions of the fifth meniscus lens 15 and the sixth meniscus lens 16 are opposite and they have positive optical power to converge light.

[0045] In this embodiment, the aperture stop 5 between the first lens group 1 and the second lens group 2 is an aperture stop 5.

[0046] In this embodiment, the seventh meniscus lens 21 and the ninth meniscus lens 23 in the second lens group 2 have the same meniscus direction and their convex sides face the object plane 4. The seventh meniscus lens 21 and the eighth meniscus lens 22 have opposite meniscus directions and negative optical power, which are used to diverge the light beam. The first biconvex lens 24 and the second biconvex lens 25 have positive optical power, which are used to converge the light beam and reduce the divergence angle.

[0047] In this embodiment, the first biconcave lens 31 has negative spherical aberration, which is used to correct the overall spherical aberration of the deep ultraviolet infinity imaging detection objective.

[0048] In this embodiment, the interval between the second lens group 2 and the third lens group 3 can be adjusted to compensate for axial defocus.

[0049] In this embodiment, the image-side working distance of the deep ultraviolet infinity imaging detection objective is infinity, and the object-side working distance is greater than 3.5 mm.

[0050] In this embodiment, the diameter of the object surface 4 of the deep ultraviolet infinity imaging detection objective lens is 1.2 mm. The object surface 4 is a circular surface with a diameter of 1.2 mm.

[0051] In this embodiment, the numerical aperture of the deep ultraviolet infinity imaging detection objective is 0.85.

[0052] In this embodiment, the first lens group 1, the second lens group 2, and the third lens group 3 all use the same ARF glass material.

[0053] The deep ultraviolet infinity imaging objective lens uses a spherical lens made of the same optical material, which facilitates processing and testing.

[0054] Table 1 provides the specific parameters of the deep ultraviolet infinity imaging detection objective. A positive radius value R indicates that the center of curvature is closer to the image side, while a negative radius value R indicates that the center of curvature is closer to the object side. The units for radius, thickness, and half-aperture are all millimeters.

[0055] Table 1. Specific parameters of the deep ultraviolet infinity imaging detection objective.

[0056]

[0057] Obviously, the above-disclosed embodiments of the present invention are merely illustrative of the invention. The embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. It is neither necessary nor possible to exhaustively describe all embodiments herein.

Claims

1. A deep ultraviolet infinity imaging detection objective, characterized in that, include: The first lens group (1), the aperture (5), the second lens group (2) and the third lens group (3) are arranged sequentially from the object plane (4) along the optical axis. The light passes through the first lens group (1), the aperture (5), the second lens group (2) and the third lens group (3) in sequence, and the light emitted from the third lens group (3) is parallel light. The first lens group (1) has positive optical power. The first lens group (1) includes a first meniscus lens (11), a second meniscus lens (12), a third meniscus lens (13), a fourth meniscus lens (14), a fifth meniscus lens (15) and a sixth meniscus lens (16) arranged sequentially from the object plane (4) to the image plane. The second lens group (2) has positive optical power. The second lens group (2) includes a seventh meniscus lens (21), an eighth meniscus lens (22), a ninth meniscus lens (23), a first biconvex lens (24), and a second biconvex lens (25) arranged sequentially from the object plane (4) toward the image plane. The third lens group (3) has negative optical power. The third lens group (3) includes a first biconcave lens (31), a tenth meniscus lens (32), a second biconcave lens (33) and an eleventh meniscus lens (34) arranged sequentially from the object plane (4) to the image plane. The first meniscus lens (11), second meniscus lens (12), third meniscus lens (13), fourth meniscus lens (14), and fifth meniscus lens (15) in the first lens group (1) have the same meniscus direction, and their convex sides all face the image plane. The meniscus directions of the fifth meniscus lens (15) and the sixth meniscus lens (16) are opposite. The first meniscus lens (11), third meniscus lens (13), fourth meniscus lens (14), fifth meniscus lens (15), and sixth meniscus lens (16) all have positive optical power; the second meniscus lens (12) has negative optical power. In the second lens group (2), the crescent directions of the seventh meniscus lens (21) and the ninth meniscus lens (23) are the same, and their convex sides are both facing the object plane (4). The crescent directions of the seventh meniscus lens (21) and the eighth meniscus lens (22) are opposite. The seventh meniscus lens (21) has a positive optical power, while the eighth meniscus lens (22) and the ninth meniscus lens (23) have negative optical power. The first biconvex lens (24) and the second biconvex lens (25) have positive optical power. The first biconcave lens (31) and the second biconcave lens (33) have negative optical power; the tenth meniscus lens (32) and the eleventh meniscus lens (34) have positive optical power; The interval between the second lens group (2) and the third lens group (3) can be adjusted to compensate for axial defocus.

2. The deep ultraviolet infinity imaging detection objective lens according to claim 1, characterized in that: The aperture stop (5) is an aperture stop (5).

3. The deep ultraviolet infinity imaging detection objective lens according to claim 1, characterized in that: The first biconcave lens (31) has negative spherical aberration and is used to correct the overall spherical aberration of the deep ultraviolet infinity imaging detection objective.

4. The deep ultraviolet infinity imaging detection objective lens according to claim 1, characterized in that: The image-side working distance of the deep ultraviolet infinity imaging objective lens is infinity, and the object-side working distance is greater than 3.5 mm.

5. The deep ultraviolet infinity imaging detection objective lens according to claim 1, characterized in that: The diameter of the object plane (4) of the deep ultraviolet infinity imaging objective lens is 1.2 mm.

6. The deep ultraviolet infinity imaging detection objective lens according to claim 1, characterized in that: The numerical aperture of the deep ultraviolet infinity imaging objective is 0.

85.

7. The deep ultraviolet infinity imaging detection objective lens according to claim 1, characterized in that: The first lens group (1), the second lens group (2), and the third lens group (3) all use the same ARF glass material.

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