Automatic focusing image quality compensation device coaxial with deep ultraviolet objective lens
By adding a compensating lens in the optical path and adjusting its position, the problem of insufficient coaxiality of the deep ultraviolet objective lens in the traditional focusing system is solved, and automatic focusing and efficient defect detection are achieved.
Patent Information
- Application Number
- CN202422790245.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-09-23
- Estimated Expiration
- 2034-11-15
AI Technical Summary
Traditional focusing systems have difficulty ensuring the coaxiality of deep ultraviolet objectives, resulting in poor imaging quality and affecting the performance of defect detection systems.
A first compensation lens and a second compensation lens are added to the optical path, and their positions are adjusted to be coaxial with the DUV objective lens through an adjustment component to ensure that the wafer is automatically focused within the focal depth range.
Automatic focusing in the coaxial direction of the DUV objective lens is achieved to ensure that the wafer is within the focal depth range, thereby improving imaging quality and defect detection effects.
Smart Images
Figure CN223377541U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of optics and mechanical design, and specifically relates to the field of automatic focusing of a pattern wafer defect detection system, in particular to an automatic focusing image quality compensation device coaxial with a deep ultraviolet objective lens. Background Art
[0002] With the continuous advancement of semiconductor manufacturing technology, process dimensions are becoming increasingly refined, and correspondingly, defect sizes are also becoming smaller. Defects include particles, pattern defects, and scratches on the wafer surface. Inspection equipment for advanced processes has reached DUV (deep ultraviolet) wavelength levels. To ensure chip production quality and improve yield, efficient wafer inspection is required to identify defects even at the nanometer level. Due to the shallow depth of focus of DUV objective lenses, patterned wafer defect inspection systems require automatic focusing of the wafer on the same axis of the objective lens to ensure that the wafer is within the focal depth of the objective lens.
[0003] However, traditional focusing systems have difficulty ensuring coaxiality with the DUV objective lens, and traditional focusing systems use infrared beams to reduce the impact on the lighting system, resulting in poor imaging quality of the focused spot on the wafer, thereby affecting the overall performance of the defect detection system.
[0004] Therefore, it is urgent to develop a new deep ultraviolet objective lens coaxial automatic focusing image quality compensation device to solve the technical problems of how to make up for the DUV objective lens's insufficient infrared band and ensure coaxiality with the DUV objective lens.
[0005] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Utility Model Content
[0006] The disclosed embodiments at least provide a deep ultraviolet objective lens coaxial automatic focusing image quality compensation device.
[0007] In a first aspect, an embodiment of the present disclosure provides an automatic focusing image quality compensation device coaxial with a deep ultraviolet objective lens, comprising: a first compensation lens and a second compensation lens; wherein the first compensation lens and the second compensation lens are located on the optical path, and the first compensation lens and the second compensation lens are glued together.
[0008] In an optional embodiment, the curvature radius of the first curved surface on the first compensating lens facing away from the second compensating lens is 149 mm to 151 mm; the curvature radius of the bonding surface between the first compensating lens and the second compensating lens is -102 mm to -100 mm; and the curvature radius of the second curved surface on the second compensating lens facing away from the first compensating lens is -207 mm to -205 mm.
[0009] In an optional embodiment, the automatic focusing image quality compensation device further includes: an adjustment component; the first compensation lens and the second compensation lens are movably connected to the adjustment component; and the adjustment component is suitable for adjusting the positions of the first compensation lens and the second compensation lens.
[0010] In an optional embodiment, the adjustment assembly includes: an outer ring, an inner ring and a fine-tuning unit; the outer ring is arranged on the outside of the inner ring, the first compensation lens and the second compensation lens are connected to the inner ring, and the fine-tuning unit passes through the outer ring and the inner ring; the fine-tuning unit is suitable for pushing the inner ring to move in the outer ring; and the fine-tuning unit is also suitable for pushing the inner ring to reset.
[0011] In an optional embodiment, the fine-tuning unit includes: a first pusher, a second pusher and an elastic reset pusher; the outer ring is provided with a radially arranged first insertion hole, a second insertion hole and a third insertion hole, and the inner ring is provided with corresponding first insertion groove, second insertion groove and third insertion groove; the first pusher is movably connected to the first insertion hole and the first insertion groove, the second pusher is movably connected to the second insertion hole and the second insertion groove, one end of the elastic reset pusher is connected to the third insertion groove, and the other end of the elastic reset pusher is connected to the third insertion hole.
[0012] In an optional embodiment, the first pushing member includes: a first fine-tuning screw; the first fine-tuning screw is threadedly connected to the first insertion hole and the first insertion groove; the second pushing member includes: a second fine-tuning screw; the second fine-tuning screw is threadedly connected to the second insertion hole and the second insertion groove.
[0013] In an optional embodiment, the first insertion hole is arranged at 90 degrees to the second insertion hole, the third insertion hole is arranged at 135 degrees to the first insertion hole, and the third insertion hole is arranged at 135 degrees to the second insertion hole.
[0014] In an optional embodiment, a converging lens group is provided on the side of the first compensation lens facing away from the second compensation lens, and an objective lens is provided on the side of the second compensation lens facing away from the first compensation lens.
[0015] In an optional embodiment, a reflecting mirror and a beam splitting prism are sequentially arranged between the converging lens group and the first compensating lens; and a dichroic mirror is arranged between the second compensating lens and the objective lens.
[0016] In an optional embodiment, a focusing light source is provided on one side of the converging mirror group, and an illumination light source is provided on one side of the dichroic mirror.
[0017] The beneficial effect of the present invention is that the present invention can compensate for the deficiency of the DUV objective lens in the infrared band by adding the first compensation lens and the second compensation lens in the optical path of the front section of the automatic focusing, and the adjustment component adjusts the positions of the first compensation lens and the second compensation lens to be coaxial with the DUV objective lens, thereby realizing automatic focusing of the wafer in the coaxial direction of the DUV objective lens and ensuring that the wafer is within the focal depth range of the DUV objective lens.
[0018] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The objectives and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.
[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0021] Figure 1 A structural diagram of an automatic focusing image quality compensation device provided by an embodiment of the present disclosure;
[0022] Figure 2 A structural diagram of an adjustment component provided in an embodiment of the present disclosure;
[0023] Figure 3 This is a diagram of the overall assembly of an automatic focusing image quality compensation device provided in an embodiment of the present disclosure.
[0024] In the picture:
[0025] 1. First compensating lens; 101. Curved surface 1; 102. Glued surface;
[0026] 2. Second compensating lens; 201. Curved surface 2;
[0027] 3. Optical path;
[0028] 4. Adjustment assembly; 41. Outer ring; 411. First insertion hole; 412. Second insertion hole; 413. Third insertion hole; 42. Inner ring; 421. First insertion slot; 422. Second insertion slot; 423. Third insertion slot; 43. Fine-tuning unit; 431. First pusher; 432. Second pusher; 433. Elastic reset pusher;
[0029] 5. Converging mirror group;
[0030] 6. Objective lens;
[0031] 7. Reflector;
[0032] 8. Beam splitter prism;
[0033] 9. Dichroic mirror;
[0034] 10. Focus the light source;
[0035] 11. Lighting source;
[0036] 12. Wafer. DETAILED DESCRIPTION
[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.
[0038] In this document, when it is mentioned that a first component is located on a second component, this may mean that the first component may be directly formed on the second component, or that a third component may be interposed between the first component and the second component. In addition, in the drawings, the thickness of components may be exaggerated or reduced in order to effectively describe technical content.
[0039] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an" and "the" may also be intended to include plural forms, unless otherwise clearly indicated herein. The terms "comprise", "include" and "have" are inclusive and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the particular order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.
[0040] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations, aspects, or designs. Instead, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.
[0041] Research has found that the wavelength of the illumination light source 11 is in the ultraviolet band, while the wavelength of the focusing light source 10 is in the infrared band. It is very difficult for the objective lens 6 with a large NA (numerical aperture) value to achieve a good focusing effect at both wavelengths. Therefore, it is necessary to make up for the deficiency of the objective lens 6 in the infrared band.
[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.
[0043] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.
[0044] like Figures 1 to 3 As shown, at least one embodiment provides an automatic focusing image quality compensation device coaxial with a deep ultraviolet objective lens 6, which includes: a first compensation lens 1 and a second compensation lens 2; wherein the first compensation lens 1 and the second compensation lens 2 are located on the optical path 3, and the first compensation lens 1 and the second compensation lens 2 are glued together.
[0045] Specifically, since the objective lens 6 requires the incident light to be parallel light, there are two options for the design of the first compensation lens 1 and the second compensation lens 2. Figure 1 One is to be far away from the objective lens 6 (the distance is 155mm), but the overall size of the first compensation lens 1 and the second compensation lens 2 (R>23.5mm) will increase accordingly; the other is to be close to the objective lens 6 (the distance is 55mm), and the overall size of the first compensation lens 1 and the second compensation lens 2 (R>20mm) will decrease accordingly. Reducing the lens size can reduce the processing difficulty and the size of the mechanical structure.
[0046] In at least one embodiment, by adding a first compensating lens 1 and a second compensating lens 2 to the optical path 3 before the automatic focusing, the deficiency of the DUV objective lens 6 in the infrared band can be compensated, and the adjustment component 4 adjusts the position of the first compensating lens 1 and the second compensating lens 2 to be coaxial with the DUV objective lens 6, thereby achieving automatic focusing of the wafer 12 in the coaxial direction of the DUV objective lens 6 and ensuring that the wafer 12 is within the focal depth range of the DUV objective lens 6.
[0047] In at least one embodiment, see Figure 1 The radius of curvature of the curved surface 101 on the first compensating lens 1 facing away from the second compensating lens 2 is 149 mm to 151 mm; the radius of curvature of the bonding surface 102 between the first compensating lens 1 and the second compensating lens 2 is -102 mm to -100 mm; and the radius of curvature of the curved surface 201 on the second compensating lens 2 facing away from the first compensating lens 1 is -207 mm to -205 mm.
[0048] Specifically, the thickness of curved surface 101 is 14mm to 16mm, and curved surface 101 is made of H-BAK3 optical material; the thickness of bonding surface 102 is 5mm to 7mm, and bonding surface 102 is made of H-ZF73 optical material; the thickness of curved surface 201 is 119mm to 121mm, and curved surface 201 is made of air optical material.
[0049] Specifically, the curvature radius of the curved surface 101 is 150.32 mm, and the thickness of the curved surface 101 is 15 mm; the curvature radius of the gluing surface 102 is -101.42 mm, and the thickness of the gluing surface 102 is 6 mm; the curvature radius of the curved surface 201 is 206.65 mm, and the thickness of the curved surface 201 is 120 mm.
[0050] In at least one embodiment, see Figure 2 The automatic focusing image quality compensation device also includes: an adjustment component 4; the first compensation lens 1 and the second compensation lens 2 are movably connected to the adjustment component 4; the adjustment component 4 is suitable for adjusting the positions of the first compensation lens 1 and the second compensation lens 2.
[0051] Specifically, the adjustment component 4 can adjust the positions of the first compensation lens 1 and the second compensation lens 2 so that the optical axis of the optical path 3 is consistent with the optical axis of the objective lens 6 .
[0052] In at least one embodiment, see Figure 2The adjustment component 4 includes: an outer ring 41, an inner ring 42 and a fine-tuning unit 43; the outer ring 41 is arranged on the outside of the inner ring 42, the first compensation lens 1 and the second compensation lens 2 are connected to the inner ring 42, and the fine-tuning unit 43 passes through the outer ring 41 and the inner ring 42; the fine-tuning unit 43 is suitable for pushing the inner ring 42 to move in the outer ring 41; and the fine-tuning unit 43 is also suitable for pushing the inner ring 42 to reset.
[0053] Specifically, the outer ring 41 movably limits the inner ring 42 , and the outer ring 41 can fine-tune the position of the inner ring 42 , thereby fine-tuning the positions of the first compensation lens 1 and the second compensation lens 2 .
[0054] In at least one embodiment, see Figure 2 The fine-tuning unit 43 includes: a first pushing member 431, a second pushing member 432 and an elastic reset pushing member 433; the outer ring 41 is provided with a radially arranged first insertion hole 411, a second insertion hole 412 and a third insertion hole 413, and the inner ring 42 is provided with corresponding first insertion grooves 421, second insertion grooves 422 and third insertion grooves 423; the first pushing member 431 is movably connected to the first insertion hole 411 and the first insertion groove 421, the second pushing member 432 is movably connected to the second insertion hole 412 and the second insertion groove 422, one end of the elastic reset pushing member 433 is connected to the third insertion groove 423, and the other end of the elastic reset pushing member 433 is connected to the third insertion hole 413.
[0055] In at least one embodiment, the first pushing member 431 includes: a first fine-tuning screw; the first fine-tuning screw is threadedly connected to the first insertion hole 411 and the first insertion slot 421; the second pushing member 432 includes: a second fine-tuning screw; the second fine-tuning screw is threadedly connected to the second insertion hole 412 and the second insertion slot 422.
[0056] In at least one embodiment, the first insertion hole 411 and the second insertion hole 412 are arranged at 90 degrees, the third insertion hole 413 and the first insertion hole 411 are arranged at 135 degrees, and the third insertion hole 413 and the second insertion hole 412 are arranged at 135 degrees.
[0057] Specifically, the first fine-tuning screw and the second fine-tuning screw are vertically arranged, and can respectively control the first compensation lens 1 and the second compensation lens 2 to move along the X direction or the Y direction to ensure that the optical axis of the optical path 3 is consistent with the optical axis of the objective lens 6.
[0058] Specifically, the elastic reset pusher 433 is a spring, which can easily reset the first compensation lens 1 and the second compensation lens 2.
[0059] In at least one embodiment, see Figure 3 A converging lens group 5 is provided on the side of the first compensation lens 1 facing away from the second compensation lens 2 , and an objective lens 6 is provided on the side of the second compensation lens 2 facing away from the first compensation lens 1 .
[0060] In at least one embodiment, see Figure 3 A reflecting mirror 7 and a beam splitter prism 8 are sequentially arranged between the converging lens group 5 and the first compensating lens 1 ; a dichroic mirror 9 is arranged between the second compensating lens 2 and the objective lens 6 .
[0061] In at least one embodiment, see Figure 3 A focusing light source 10 is provided on one side of the converging lens group 5 , and an illumination light source 11 is provided on one side of the dichroic mirror 9 .
[0062] Specifically, the specific parameters of the objective lens 6 are determined by the illumination light source 11 , and the first compensating lens 1 and the second compensating lens 2 determine the specific parameters according to the specifications of the objective lens 6 , thereby compensating the imaging quality of the objective lens 6 in the red light band.
[0063] Before installing the first and second compensating lenses 1 and 2, the optical axis of the front optical path 3 is aligned with the optical axis of the objective lens 6 using the indicator laser emitted by the focusing light source 10. After installing the first and second compensating lenses 1 and 2, the corresponding fine-tuning screws of the first and second compensating lenses 1 and 2 are adjusted according to the offset of the indicator laser in the X and Y directions until the offset of the indicator laser disappears. After adjustment, image quality changes are compensated and the optical axis of the autofocus optical path 3 is ensured to be aligned with the optical axis of the objective lens 6.
[0064] To sum up, the utility model can make up for the deficiency of the DUV objective lens in the infrared band by adding the first compensation lens and the second compensation lens in the optical path of the front section of the automatic focusing, and the adjustment component adjusts the position of the first compensation lens and the second compensation lens to be coaxial with the DUV objective lens, thereby realizing automatic focusing of the wafer in the coaxial direction of the DUV objective lens and ensuring that the wafer is within the focal depth range of the DUV objective lens.
[0065] In the description of the embodiments of the present invention, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.
[0066] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, terms such as "first", "second" and other numerical terms do not imply an order or sequence when used herein unless expressly indicated above. Therefore, without departing from the teachings of the example embodiments, the first element, component, region, layer or section discussed above may be referred to as a second element, component, region, layer or section.
[0067] Spatially relative terms, such as "inside," "outside," "below," "beneath," "down," "above," "on," etc., may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figures. In addition to the orientations depicted in the figures, spatially relative terms may be intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as being "below" or "below" other elements or features will be oriented to be "above" the other elements or features. Thus, the example term "below" may encompass both above and below orientations. The device may be oriented otherwise (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.
[0068] In the above discussion, unless otherwise indicated, the terms "about," "approximately," "substantially," etc., when used to describe a numerical value, mean a variation of + / - 10% of the value.
[0069] Based on the above-mentioned ideal embodiment of the present invention, and in accordance with the above description, relevant personnel can make various changes and modifications without departing from the technical scope of the present invention. The technical scope of the present invention is not limited to the content of the specification, but must be determined according to the scope of the claims.
Claims
1. A deep ultraviolet objective lens coaxial automatic focusing image quality compensation device, characterized in that: include: A first compensating lens (1), a second compensating lens (2), and an adjustment component (4); in The first compensation lens (1) and the second compensation lens (2) are located on the optical path (3), and the first compensation lens (1) and the second compensation lens (2) are glued together; The first compensating lens (1), the second compensating lens (2) and the adjusting component (4) are movably connected; The adjustment component (4) is suitable for adjusting the positions of the first compensation lens (1) and the second compensation lens (2); The adjustment assembly (4) comprises: an outer ring (41), an inner ring (42) and a fine-tuning unit (43); The outer ring (41) is sleeved on the outside of the inner ring (42), the first compensation lens (1) and the second compensation lens (2) are connected to the inner ring (42), and the fine-tuning unit (43) passes through the outer ring (41) and the inner ring (42); The fine-tuning unit (43) is suitable for pushing the inner ring (42) to move in the outer ring (41); and The fine-tuning unit (43) is also suitable for pushing the inner ferrule (42) to reset.
2. The automatic focusing image quality compensation device according to claim 1, wherein: The radius of curvature of the curved surface 1 (101) on the first compensating lens (1) facing away from the second compensating lens (2) is 149 mm to 151 mm; The curvature radius of the bonding surface (102) of the first compensation lens (1) and the second compensation lens (2) is -102 mm to -100 mm; The radius of curvature of the second curved surface (201) on the second compensating lens (2) facing away from the first compensating lens (1) is -207 mm to -205 mm.
3. The automatic focusing image quality compensation device according to claim 1, wherein: The fine-tuning unit (43) comprises: a first pushing member (431), a second pushing member (432) and an elastic reset pushing member (433); The outer ring (41) is provided with a first insertion hole (411), a second insertion hole (412) and a third insertion hole (413) arranged radially, and the inner ring (42) is provided with a corresponding first insertion groove (421), a second insertion groove (422) and a third insertion groove (423); The first pushing member (431) is movably connected to the first insertion hole (411) and the first insertion groove (421); the second pushing member (432) is movably connected to the second insertion hole (412) and the second insertion groove (422); the elastic reset pushing member (433) is connected to the third insertion groove (423); and the elastic reset pushing member (433) is connected to the third insertion hole (413).
4. The automatic focusing image quality compensation device according to claim 3, wherein: The first pushing member (431) comprises: a first fine-tuning screw; The first fine-tuning screw is threadably connected to the first insertion hole (411) and the first insertion slot (421); The second pushing member (432) comprises: a second fine-tuning screw; The second fine-tuning screw is threadably connected to the second insertion hole (412) and the second insertion slot (422).
5. The automatic focusing image quality compensation device according to claim 3, wherein: The first insertion hole (411) and the second insertion hole (412) are arranged at 90 degrees, the third insertion hole (413) and the first insertion hole (411) are arranged at 135 degrees, and the third insertion hole (413) and the second insertion hole (412) are arranged at 135 degrees.
6. The automatic focusing image quality compensation device according to claim 3, wherein: A converging lens group (5) is provided on the side of the first compensating lens (1) facing away from the second compensating lens (2), and an objective lens (6) is provided on the side of the second compensating lens (2) facing away from the first compensating lens (1).
7. The automatic focusing image quality compensation device according to claim 6, wherein: A reflector (7) and a beam splitter prism (8) are sequentially arranged between the converging lens group (5) and the first compensating lens (1); A dichroic mirror (9) is provided between the second compensation lens (2) and the objective lens (6).
8. The automatic focusing image quality compensation device according to claim 7, wherein: A focusing light source (10) is provided on one side of the converging mirror group (5), and an illumination light source (11) is provided on one side of the dichroic mirror (9).