Alignment device and alignment method

Abstract

The present application discloses an alignment device and an alignment method, and relates to the field of alignment technology. In the present application, the lighting system is used to emit light; the lens assembly is used to transmit light; the image receiving element is used to receive the light transmitted through the lens assembly; the first marking plate is used to transmit the light emitted by the lighting system and transmit it to the lens assembly; the second marking plate is used to transmit the light transmitted through the lens assembly and transmit it to the image receiving element; the image receiving element is configured to form a moiré pattern based on light for determining the relative position of the first marking plate and the second marking plate. The present application uses the discrete uniformity and relative density of the Delone set to restrict the positive and negative patterns on the two marking plates. In the process of displacement information recognition, the non-periodic uniform and discrete two-dimensional distribution makes the spatial beat frequency form only a unique large spot, and other areas are evenly distributed in the blurred state, ensuring the uniqueness of the result.

Description

Technical Field

[0001] The present application relates to the field of alignment technology, and in particular to an alignment device and an alignment method. Background Art

[0002] In the semiconductor industry, the most common alignment method is imaging alignment, which can obtain specific position information in one imaging without scanning, but is often subject to the diffraction limit. For example, for sub-wavelength or even smaller scale alignment, a higher camera sensitivity depth is required, and it is also very sensitive to camera noise. If the image taken by the camera has a large noise, it will interfere with the fitting of the diffraction spot and affect the alignment result. Summary of the invention

[0003] In order to solve the above technical problems, a technical solution adopted in the present application is: an alignment device, comprising:

[0004] a lighting system for emitting light;

[0005] a lens assembly for transmitting the light;

[0006] An image receiving element, used for receiving light passing through the lens assembly;

[0007] a first marking plate, located at the object plane of the lens assembly, for transmitting the light emitted by the illumination system to the lens assembly, a positive pattern being arranged on the first marking plate to diffract the light, and the first marking plate being configured to form an image on the image plane of the lens assembly;

[0008] a second marking plate, located on the image plane of the lens assembly, for transmitting the light transmitted through the lens assembly to the image receiving element; the image receiving element is configured to form a moiré pattern for determining the relative position of the first marking plate and the second marking plate based on the light, and a negative pattern is provided on the second marking plate;

[0009] Wherein, the positive pattern includes a plurality of first graphic units arranged at intervals, and a first point set formed by marking points of each of the plurality of first graphic units is a Delone set; the negative pattern includes a plurality of second graphic units arranged at intervals, and a second point set formed by marking points of each of the plurality of second graphic units is a Delone set; when the positive pattern is enlarged m times and rotated 180°, the first point set covers the second point set of the negative pattern, or when the positive pattern is enlarged m times, the first point set covers the second point set of the negative pattern; m>0.

[0010] In order to solve the above technical problems, a technical solution adopted in the present application is: an alignment method, comprising:

[0011] Acquire a moiré pattern using any of the alignment devices described above;

[0012] Determining a first centroid position of the moiré pattern;

[0013] Determining a first displacement corresponding to the first center of gravity position based on a mapping relationship between the center of gravity position and the displacement;

[0014] The relative positions of the first marking plate and the second marking plate are adjusted based on the first displacement amount.

[0015] By adopting the above technical solution, the present application diffracts the negative pattern on the first marking plate, and the pattern formed on the image plane of the lens assembly is close to the period of the pattern of the second marking plate, generating a spatial beat frequency, which can form a moiré pattern received by the image receiving component, and obtain the amplified displacement information after processing the moiré pattern. The distribution of the positive and negative patterns on the two marking plates is restricted by the discrete uniformity (uniformly discrete) and relative density (relatively dense) of the Delone set. In the process of displacement information recognition, the non-periodic uniformly discrete two-dimensional distribution makes the spatial beat frequency form only a unique large spot, and other areas are evenly distributed in the blurred state, ensuring the uniqueness of the result. In addition, because the scale of the moiré spot is much larger than the pixel scale, there is more effective information, so a higher camera photosensitivity bit depth is not required, and the influence of noise on recognition accuracy can also be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present application and are used together with the specification to illustrate the technical solution of the present application.

[0017] Figure 1 This is a schematic diagram of the framework of the alignment system in some embodiments of the present application;

[0018] Figure 2 for Figure 1 A schematic diagram of a framework of the alignment system 100 in the illustrated embodiment in other embodiments;

[0019] Figure 3 is the light intensity distribution diagram after the light passes through the first marking plate;

[0020] Figure 4 is the light intensity distribution diagram before the light passes through the second marking plate;

[0021] Figure 5 is the light intensity distribution diagram after the light passes through the second marking plate;

[0022] Figure 6 It is a photosensitivity distribution diagram when light forms an image in an image receiving element;

[0023] Figure 7 is a schematic diagram of light transmittance of the second marking plate;

[0024] Figure 8 is the moiré pattern when the relative displacement between the first marking plate and the second marking plate in the positive direction of the horizontal axis is 0 nm;

[0025] Fig. 9 is the moiré pattern when the relative displacement between the first marking plate and the second marking plate in the positive direction of the horizontal axis is 100 nm;

[0026] Fig.10 is the moiré pattern when the relative displacement between the first marking plate and the second marking plate in the positive direction of the horizontal axis is 200 nm;

[0027] Fig.11 is the moiré pattern when the relative displacement between the first marking plate and the second marking plate in the positive direction of the horizontal axis is 500 nm;

[0028] Fig.12 is the moiré pattern when the relative displacement between the first marking plate and the second marking plate in the positive direction of the horizontal axis is 1 μm;

[0029] Fig.13 A surface calibration relationship mapping diagram generated by aligning the first marking plate and the second marking plate on the y-axis and moving on the x-axis;

[0030] Fig.14 A surface calibration relationship mapping diagram generated by the first marking plate and the second marking plate moving on the x-axis and / or the y-axis. DETAILED DESCRIPTION

[0031] The present application is further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0032] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] Next, an alignment system is described. The alignment system utilizes the discrete uniformity and relative density of the Delone set. In the process of displacement information recognition, the alignment system can obtain a non-periodic uniform discrete two-dimensional distribution, so that the spatial beat frequency only forms a unique large spot, and other areas are evenly distributed in the blurred state, ensuring the uniqueness of the result.

[0034] In some embodiments, for the Delone set, let X be an R on the complex plane C 2 A subset of . Let B(x, r) represent the sphere with x as the center and r as the radius. If there exists r>0, and for any x∈C, Then X is r-relatively dense. If there exists s>0, and for any x∈C, the set (B(x, s)∩X) has ≤ 1 elements, then X is s-discrete uniform. If X is both r-relatively dense and s-discrete uniform, then X is a (r, s) Delone set.

[0035] In some embodiments, the Delone set may have the following restrictions: (a) any two points are separated by a given minimum distance; (b) there exists a given radius such that every sphere of the radius contains at least one point.

[0036] It can be seen that the Delone set has discrete uniformity and relative density.

[0037] See also Figure 1 , Figure 1 Schematic diagram of the framework of the alignment system in some embodiments of the present application. The alignment system 100 may include a first alignment member 101, a second alignment member 102 aligned with the first alignment member 101, and an alignment device 103 for performing alignment detection on the first alignment member 101 and the second alignment member 102. In some embodiments, the alignment device 103 may move the first alignment member 101 and / or the second alignment member 102 based on the alignment detection result to achieve alignment and cooperation with the first alignment member 101 and the second alignment member 102. Of course, other structures in the alignment system 100 may also move the first alignment member 101 and / or the second alignment member 102 based on the alignment detection result to achieve alignment and cooperation with the first alignment member 101 and the second alignment member 102.

[0038] The alignment system 100 can be used in semiconductor manufacturing, medical machine surgery, scientific research and other precision automation fields that require micro-nano scale alignment, as well as position feedback systems of some nano-piezoelectric motion systems. Correspondingly, the first alignment member 101 and the second alignment member 102 can be instruments in semiconductor manufacturing, medical machine surgery, scientific research and other precision automation fields that require micro-nano scale alignment, as well as instruments in position feedback systems of some nano-piezoelectric motion systems.

[0039] In some embodiments, in the semiconductor IC (Integrated Circuit) chip manufacturing process, a complete chip usually needs to undergo multiple photolithography exposures to be completed. Except for the first photolithography, the remaining layers of photolithography must accurately position the graphics of that layer with the graphics left by the previous layer exposure before exposure, so as to ensure that each layer of graphics has the correct relative position, that is, the overlay accuracy. In the field of projection lithography, the first alignment member 101 can be one of the silicon wafer and the mask, and the second alignment member 102 can be the other of the silicon wafer and the mask. The positional relationship between the silicon wafer and the mask can be obtained by the alignment device 103.

[0040] In some embodiments, in an imprint lithography process, the first alignment feature 101 may be one of a substrate and a template, and the second alignment feature 102 may be the other of the substrate and the template.

[0041] In some embodiments, three-dimensional integration technology can be used to stack chips or device units in the vertical direction to improve device capacity. Precise alignment of wafer bonding is crucial. The first alignment piece 101 can be one of the upper and lower wafers, and the second alignment piece 102 can be the other of the upper and lower wafers.

[0042] The first alignment member 101 and the second alignment member 102 may be adjusted according to different environments, and may be adjusted specifically according to techniques well known to those skilled in the art, and the specific structures of the first alignment member 101 and the second alignment member 102 may not be specifically limited.

[0043] See also Figure 1, the alignment device 103 may include an illumination system 10 for emitting light, and a first marking plate 20, a lens assembly 30, a second marking plate 40, and an image receiving member 50 arranged in sequence on the propagation optical path of the light emitted by the illumination system 10. The light emitted by the illumination system 10 propagates on the optical path. During the propagation process, the light may sequentially pass through the first marking plate 20, the lens assembly 30, and the second marking plate 40, and be received by the image receiving member 50. Specifically, after the light passes through the first marking plate 20, the lens assembly 30, and the second marking plate 40, a Moiré pattern may be formed, and the light may be received by the image receiving member 50. The alignment system 100, such as the alignment device 103, may determine the relative position of the first marking plate 20 and the second marking plate 40 based on the Moiré pattern. In some embodiments, the first marking plate 20 is fixedly connected to the first alignment member 101, and the second marking plate 40 is fixedly connected to the second alignment member 102. Then, the alignment system 100, such as the alignment device 103, may determine the relative position of the first alignment member 101 and the second alignment member 102 based on the Moiré pattern. In some embodiments, the first marking plate 20 is fixedly connected to the second alignment member 102, and the second marking plate 40 is fixedly connected to the first alignment member 101. In some embodiments, the first marking plate 20 can be used to be fixed on the first alignment member 101, the second marking plate 40 can be used to be fixed on the second alignment member 102, and the image receiving member 50 can form a moiré pattern for determining the relative position of the first alignment member 101 and the second alignment member 102 based on light.

[0044] In some embodiments, the light path may be a straight line. Of course, in the case where there is a light deflection member such as a prism or a plane mirror in the alignment device 103, the direction of the light path can be deflected. The location of the light deflection member can be selected according to the needs of those skilled in the art. In some embodiments, the light deflection member may be arranged on the light path between the lighting system 10 and the first marking plate 20. In some embodiments, the light deflection member may be arranged on the light path between the first marking plate 20 and the lens assembly 30. In some embodiments, the light deflection member may be arranged on the light path between the lens assembly 30 and the second marking plate 40. In some embodiments, the light deflection member may be arranged on the light path between the second marking plate 40 and the image receiving member 50.

[0045] In some embodiments, the alignment device 103 may further include a lens assembly consisting of optical devices such as lenses (eg, concave lenses, convex lenses, etc.) and / or light deflection elements.

[0046] See also Figure 1, the illumination system 10 can provide collimated illumination light. In some embodiments, the collimated illumination light can be a broadband light (such as 450-750nm), or a light of multiple wavelengths, such as lasers with wavelengths of λ1, λ2, and λ3. In some embodiments, the illumination system 10 can also include a light source gating device, which can select a light source of a certain wavelength for illumination. In some embodiments, the collimated illumination light can be a 532nm broadband light. In some embodiments, the illumination system 10 can include a light source 11 and a convex lens 12. The light source 11 is the light emitting body of the illumination system 10, and the light emitted by the light source 11 passes through the convex lens 12 to form collimated illumination light, so as to be uniformly irradiated on the first marking plate 20. In some embodiments, the light source 11 can be a surface light source. In some embodiments, the light source 11 has a circular light emitting surface with a diameter of 18mm. In some embodiments, the illumination system 10 can be a Kohler illumination system. In some embodiments, the light source 11 is imaged on the image plane of the convex lens 12, and the first marking plate 20 is located on the image plane of the convex lens 12, so that the light source 11 and the first marking plate 20 are conjugate with respect to the convex lens 12. In some embodiments, the light source 11 is located at the object focal plane of the convex lens 12. In some embodiments, the first marking plate 20 is located at the image focal plane of the convex lens 12. In some embodiments, the object focal length of the convex lens 12 is 15 mm, which can be adjusted according to techniques well known to those skilled in the art. In some embodiments, the image focal length of the convex lens 12 is 15 mm, which can be adjusted according to techniques well known to those skilled in the art.

[0047] In some embodiments, the convex lens 12 can be equivalently replaced by a lens group consisting of optical devices such as lenses (eg, concave lenses, convex lenses, etc.) and / or light redirecting elements.

[0048] See also Figure 1 , the first marking plate 20 is imaged on the image plane of the lens assembly 30, and the second marking plate 40 is located on the image plane of the lens assembly 30, so that the first marking plate 20 and the second marking plate 40 are conjugate with respect to the lens assembly 30. In some embodiments, the first marking plate 20 is located on the object focal plane of the lens assembly 30. The first marking plate 20 can be used to receive and transmit (i.e., transmit and transmit) the light emitted by the illumination system 10 (e.g., the light emitted by the light source 11 and transmitted through the convex lens 12) to the lens assembly 30.

[0049] The first marking plate 20 may be provided with a positive pattern, which can cause light to diffract. Positive text refers to raised text and / or patterns formed by processes such as engraving or casting.

[0050] The positive pattern includes a plurality of first graphic units arranged at intervals, and the first point set formed by the marking points of each graphic unit in all the first graphic units can be the Delone set in the above embodiment, and thus the first point set has discrete uniformity and relative density.

[0051] In some embodiments, the first image unit may be a diffraction-capable graphic such as a circle, text, rectangle, polygon, etc., which may be selected according to the needs of those skilled in the art and is not limited. In some embodiments, the marking point may be located inside or outside the first graphic unit, and may form a unique position correspondence with the first image unit. Based on the position correspondence, the position of the marking point may be determined by the first graphic unit, or the position of the first graphic unit may be determined by the marking point.

[0052] In some embodiments, the first image unit may be a circle, and the marking point may be the center of the circle. For example, the positive pattern includes a plurality of first circles arranged at intervals, and the first point set formed by the center of each of all the first circles may be the Delone set in the above embodiment, and thus, the first point set has discrete uniformity and relative density.

[0053] In some embodiments, the diameter of the first circle is 1 μm, which can be adjusted according to techniques known to those skilled in the art without limitation. For example, the diameter of the first circle is 2 μm, 3 μm, 4 μm, etc., which can form a diffraction size.

[0054] In some embodiments, the Delone set may include a set of points on a spiral. In some embodiments, the first set of points may include at least some of the points on the spiral. That is, the first set of points may be arranged in the spiral direction of the spiral. In some embodiments, the spiral includes an algebraic Vogel spiral. The Vogel spiral is An algebraic Vogel spiral is a Vogel spiral where α is an algebraic number. In some embodiments, the spiral comprises a golden spiral. In some embodiments, the spiral comprises a golden Vogel spiral.

[0055] In some embodiments, the micro-nano structure formed by the positive pattern can be prepared by micro-machining, such as electron beam exposure etching or ion beam etching.

[0056] In some embodiments, the Delone set may include a set of vertices of each graphic in a Penrose quasicrystal pattern, a set of vertices of each graphic in a quasicrystal pattern obtained by a Voronoi diagram algorithm, a set of vertices of each graphic in a rotationally symmetric two-dimensional quasicrystal pattern, or a set of dual vertices obtained by a Voronoi diagram algorithm. In some embodiments, the first point set is a set of at least some vertices of each graphic in a Penrose quasicrystal pattern, a set of at least some vertices of each graphic in a quasicrystal pattern obtained by a Voronoi diagram algorithm, a set of at least some vertices of each graphic in a rotationally symmetric two-dimensional quasicrystal pattern, or a set of dual vertices obtained by a Voronoi diagram algorithm.

[0057] It is understandable that when an infinite discrete point set in the entire two-dimensional Euclidean space forms a moiré pattern, it may have poor uniformity, difficulty in identification, interference, etc. When the first point set is required to be a Delone set, the moiré pattern and the space outside the moiré pattern can be uniform after homogenization, so that the corresponding position of the moiré pattern can be more accurately and effectively identified.

[0058] In some embodiments, the first point set can be made into a circle at each point as an alignment pattern, which is easier to prepare and control the yield in micro-machining. In some embodiments, the positive pattern has rotational symmetry so that the effects of the horizontal axis and the vertical axis are close and there is no anisotropy. Since the diffraction spot under uniform illumination is isotropic, it is more convenient in engineering implementation for patterns without anisotropy.

[0059] See also Figure 1 The lens assembly 30 may include a first convex lens 31 and a second convex lens 32 that sequentially transmit light. The light that has passed through the first marking plate 20 may sequentially pass through the first convex lens 31 and the second convex lens 32. The lens assembly 30 may amplify the pattern attached to the light, and may amplify it a times. In some embodiments, a=8, which may be adjusted according to techniques known to those skilled in the art, without limitation. For example, a=10, 12, 13, 16 or 18, etc.

[0060] In some embodiments, the first marking plate 20 is imaged on the image plane of the first convex lens 31, and the second convex lens 32 may be located on the image plane of the first convex lens 31, so that the first marking plate 20 and the second convex lens 32 are conjugate with respect to the first convex lens 31. In some embodiments, the first marking plate 20 may be located on the object focal plane of the first convex lens 31, that is, on the object focal plane of the lens assembly 30.

[0061] In some embodiments, the image plane of the first convex lens 31 can be used as the object plane of the second convex lens 32, and the second marking plate 40 can be located on the image plane of the second convex lens 32, so that the second marking plate 40 and the first convex lens 31 are conjugate with respect to the second convex lens 32. In some embodiments, the second marking plate 40 can be located on the image-side focal plane of the second convex lens 32, that is, on the image-side focal plane of the lens assembly 30.

[0062] In some embodiments, the lens assembly 30 is a 4F optical system. In some embodiments, the first convex lens 31 and the second convex lens 32 may both be Fourier lenses.

[0063] In some embodiments, the object-side focal length of the first convex lens 31 is 30 mm, which can be adjusted according to techniques well known to those skilled in the art. In some embodiments, the image-side focal length of the first convex lens 31 is 30 mm, which can be adjusted according to techniques well known to those skilled in the art. In some embodiments, the first convex lens 31 can be equivalently replaced by a lens assembly consisting of optical devices such as lenses (e.g., concave lenses, convex lenses, etc.) and / or light deflection components.

[0064] In some embodiments, the object-side focal length of the second convex lens 32 is 240 mm, which can be adjusted according to techniques well known to those skilled in the art. In some embodiments, the image-side focal length of the second convex lens 32 is 240 mm, which can be adjusted according to techniques well known to those skilled in the art. In some embodiments, the second convex lens 32 can be equivalently replaced by a lens assembly consisting of optical devices such as lenses (e.g., concave lenses, convex lenses, etc.) and / or light deflection components.

[0065] In some embodiments, the lens assembly 30 may further include an aperture stop 33 , so that the lens assembly 30 becomes a double telecentric system by setting the aperture stop 33 , thereby making the magnification a of the lens assembly 30 not change with the change of the object distance.

[0066] The aperture stop 33 may be used to receive the light passing through the first convex lens 31 and transmit (ie, pass through and transmit) the light to the second convex lens 32 .

[0067] In some embodiments, the aperture stop 33 may be located at the image-side focal plane of the first convex lens 31 , or may be located at the object-side focal plane of the second convex lens 32 .

[0068] In some embodiments, the aperture of the aperture stop 33 is 25.4 mm, which can be adjusted according to techniques well known to those skilled in the art.

[0069] See also Figure 1The second marking plate 40 is located on the image plane of the lens assembly 30, such as the second convex lens 32, and is used to receive the light passing through the lens assembly 30, such as the second convex lens 32, and transmit it to the image receiving element 50. In some embodiments, the second marking plate 40 is located on the image focal plane of the lens assembly 30, such as the second convex lens 32.

[0070] The second marking plate 40 is provided with an intaglio pattern, which cooperates with the first marking plate 20 to form a moiré pattern. Intaglio refers to recessed text and / or patterns formed by engraving or casting.

[0071] The negative pattern includes a plurality of second graphic units arranged at intervals, and the second point set formed by the marking points of each graphic unit in all the second graphic units can be the Delone set in the above embodiment, and thus the second point set has discrete uniformity and relative density.

[0072] In some embodiments, the second image unit may be a diffraction-capable graphic such as a circle, text, rectangle, polygon, etc., which may be selected according to the needs of those skilled in the art and is not limited. In some embodiments, the marking point may be located inside or outside the second graphic unit, and may form a unique position correspondence with the second image unit. Based on the position correspondence, the position of the marking point may be determined by the second graphic unit, or the position of the second graphic unit may be determined by the marking point.

[0073] In some embodiments, the second image unit may be a circle, and the marking point may be the center of the circle. For example, the intaglio pattern includes a plurality of second circles arranged at intervals, and the second point set formed by the center of each of all the second circles may be the Delone set in the above embodiment, and thus, the second point set has discrete uniformity and relative density.

[0074] In order to cooperate with the imaging effect of the lens assembly 30, the first point set of the positive pattern after being magnified m times and rotated 180° can cover the second point set of the negative pattern, m>0. Of course, the positive pattern can also be magnified m times without being rotated, and the first point set covers the second point set of the negative pattern. In some embodiments, the first point set of the positive pattern after being magnified m times and rotated 180° is a subset of the second point set of the negative pattern. Of course, the positive pattern can also be magnified m times without being rotated, and the first point set covers the second point set of the negative pattern.

[0075] In some embodiments, the first point set of the positive pattern after being magnified m times and rotated 180° is equal to the second point set of the negative pattern. Of course, the positive pattern can also be magnified m times without being rotated, and the first point set covers the second point set of the negative pattern.

[0076] In some embodiments, the diameter of the second circle is 24 μm, which can be adjusted according to techniques known to those skilled in the art without limitation. In some embodiments, the diameter of the second circle can be limited and adjusted by the diameter of the first circle and the magnification a.

[0077] See also Figure 1 There are many types of image receiving element 50, which can be selected or adjusted according to different use environments. In some embodiments, the image receiving element 50 can be an image sensor such as a camera, a computer or a mobile phone, etc., which has a camera function.

[0078] It is understandable that the alignment system 100, such as the alignment device 103, may also have a device that processes the moiré pattern and may have a processor, so as to obtain the relative position of the first marking plate 20 and the second marking plate 40, or the relative position of the first alignment member 101 and the second alignment member 102 by processing the moiré pattern. In some embodiments, the device with a processor may be a single-chip microcomputer, a computer, a mobile phone, or a server, etc., which can perform logical operations, command generation, and information processing. The specific selection can be made according to the needs of those skilled in the art, and is not specifically limited. The device with a processor may also be, for example, a game console, a personal computer, a tablet computer, a smart phone, or other types of processing devices.

[0079] See also Figure 2 , Figure 2 for Figure 1 The framework schematic diagram of the alignment system 100 in the illustrated embodiment in other embodiments. The alignment device 103 may include a lens assembly 60 disposed between the second marking plate 40 and the image receiving member 50. During the propagation process, the light may sequentially pass through the first marking plate 20, the lens assembly 30, the second marking plate 40 and the lens assembly 60, and be received by the image receiving member 50. The lens assembly 60 may include optical devices such as a lens (e.g., a concave lens, a convex lens, etc.) and / or a light deflection member.

[0080] In some embodiments, in order to match the imaging effect of the lens assembly 30, the positive pattern can be magnified m times, m>0. Among them, m can be close to 1, so that the slight change in the relative position of the first marking plate 20 and the second marking plate 40 can be magnified. The magnification is When the first marking plate 20 moves on the object focal plane and / or the second marking plate 40 moves on the image focal plane, the relative positions of the first marking plate 20 and the second marking plate 40 move relative to each other, causing the moiré pattern to undergo a relative displacement of M times. When the relative displacement is below the sub-wavelength or even smaller scale, the amplified displacement can be above the sub-wavelength, thereby breaking through the diffraction-limited recognition accuracy.

[0081] In some embodiments, the first set of points on the relief pattern is located on the Golden Vogel spiral. Where R = 2.5 μm, The number of points in the first point set may be 104. In some embodiments, the diameter of the first circle is 1 μm. In some embodiments, the radius of the first circle at the point where n=0 may be smaller than the radius of other first circles to avoid intersection of two adjacent first circles.

[0082] In some embodiments, the second set of points on the intaglio pattern is located on the Golden Vogel spiral. Where R = (24 × m) μm, The number of points in the second point set may be 69. In some embodiments, the diameter of the second circle is 24 μm. In some embodiments, the radius of the second circle at the point where n=0 may be smaller than the radius of other second circles to avoid intersection of two adjacent second circles.

[0083] In some embodiments, with m=0.91, Furthermore, the slight change in the relative position of the first marking plate 20 and the second marking plate 40 is magnified 10 times. In combination with the magnification a of the lens assembly 30, the ratio of the displacement of the moiré pattern to the relative displacement of the first marking plate 20 and the second marking plate 40 is 80 times. Furthermore, when the relative displacement of the first marking plate 20 and the second marking plate 40 is 100 nm, the displacement of the moiré pattern is 8 μm. The size of the small photosensitive pixel after imaging of the image receiving member 50 is about 3.2 μm, which is sufficient to capture the change corresponding to the relative displacement of the first marking plate 20 and the second marking plate 40.

[0084] In some embodiments, the light intensity distribution corresponding to each node in the alignment system 100, such as the alignment device 103, can be simulated by calculating the diffraction through physical optics. Since the simulation time of completely incoherent light is relatively long, the random phase method is used here for simplified estimation calculation, taking the sampling number of 8192 and the simulation image size of 512×512 as an example. Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 and Fig.12 , Figure 3 is the light intensity distribution diagram after the light passes through the first marking plate 20, Figure 4 is the light intensity distribution diagram before the light passes through the second marking plate 40, Figure 5 is the light intensity distribution diagram after the light passes through the second marking plate 40, Figure 6 is a photosensitivity distribution diagram when light is imaged in the image receiving member 50, Figure 7 is a schematic diagram of the light transmittance of the second marking plate 40, Figure 8 It is the moiré pattern when the relative displacement between the first marking plate 20 and the second marking plate 40 in the positive direction of the horizontal axis is 0 nm. Fig. 9 is the moiré pattern when the relative displacement between the first marking plate 20 and the second marking plate 40 in the positive direction of the horizontal axis is 100 nm, Fig.10 is the moiré pattern when the relative displacement between the first marking plate 20 and the second marking plate 40 in the positive direction of the horizontal axis is 200 nm, Fig.11 is the moiré pattern when the relative displacement between the first marking plate 20 and the second marking plate 40 in the positive direction of the horizontal axis is 500 nm, Fig.12 φ is a moiré pattern when the relative displacement between the first marking plate 20 and the second marking plate 40 in the positive direction of the horizontal axis is 1 μm.

[0085] In some embodiments, the image in the image receiving member 50 is suitable for human eye perception, but not suitable for computer calculation. In order to convert the light intensity distribution into difference coordinates, only the internal information of the circle with a diameter of 256 pixels (of course, it can be selected according to the needs of technicians in this field, and no specific limitation is made) can be taken here, and the bright part of the outer circle can be shielded. Then the center of gravity position inside the circle (the center of gravity position of the moiré pattern) is calculated. When the first marking plate 20 and the second marking plate 40 are near the alignment point, the center of gravity position and the displacement (the relative displacement of the first marking plate 20 and the second marking plate 40) have a monotonic mapping relationship, but the two axes are not independent of each other. Therefore, the surface calibration relationship mapping table between the center of gravity position and the displacement can be calculated or measured in advance, and the displacement can be obtained by calling and checking the surface calibration relationship mapping table during alignment. The zero point of the center of gravity position does not coincide with the zero point of the displacement, which is caused by the fact that the golden Vogel spiral is not mirror-symmetrical about the x-axis or the y-axis. However, this asymmetric zero point is a fixed value for a certain alignment device 100, so the influence caused by it can also be avoided by calibration through a mapping table. Fig.13 , Fig.13 The first marking plate 20 and the second marking plate 40 are aligned on the y-axis and moved on the x-axis to generate a surface calibration relationship mapping diagram. The mapping relationship between the center of gravity position and the displacement can be displayed on the surface calibration relationship mapping diagram. Near the alignment position, the mapping relationship is approximately linear. When it is far away from the alignment position, although it may no longer be monotonic, it tends to a stable and gentle value overall. At this time, a rough alignment can be performed through the bright circle on the macro periphery, so that the displacement is moved to the vicinity of the alignment position and then the surface calibration relationship mapping diagram is used. Roughly within the range of ±500nm, the mapping relationship is monotonic, and the center of gravity can be used within this range to estimate the displacement.

[0086] See also Fig.14 , Fig.14 The curved surface calibration relationship map generated by the first marking plate 20 and the second marking plate 40 moving on the x-axis and / or the y-axis. The circular range with a radius of 500 nm in the middle is monotonic. Therefore, the circular range with a radius of 500 nm can be used as the capture range of this alignment method.

[0087] In some embodiments, when the alignment system 100, such as the alignment device 103, performs alignment based on the moiré pattern, the moiré pattern may be first acquired through the image receiving element 50; then the first center of gravity position of the moiré pattern is determined; then, based on the mapping relationship between the center of gravity position and the displacement (e.g. Fig.14 The first displacement corresponding to the first center of gravity position is determined by the mapping relationship shown in the curved surface calibration relationship mapping diagram; and then the relative position of the first marking plate and the second marking plate can be adjusted based on the first displacement. Of course, in some embodiments, it is also possible to obtain only the internal information of the circle with a diameter of h pixels (in some embodiments, h is 256, which can be selected according to the needs of those skilled in the art and is not specifically limited) from the image in the image receiving member 50 according to the situation, and shield the bright part of the outer circle. Then calculate the center of gravity position inside the circle (the center of gravity position of the moiré pattern, such as the first center of gravity position, such as the center position in the mapping relationship shown in the curved surface calibration relationship mapping diagram). In some embodiments, a coarse alignment can be performed through the bright circle of the macro periphery to move the displacement to the vicinity of the alignment position, and then the first displacement of the first center position is determined using the curved surface calibration relationship mapping diagram, and then the relative position of the first marking plate and the second marking plate is adjusted based on the first displacement.

[0088] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device implementation described above is only illustrative, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0089] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0090] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0091] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An alignment device, characterized in that: include: a lighting system for emitting light; a lens assembly for transmitting the light; An image receiving element, used for receiving light passing through the lens assembly; a first marking plate, located at the object plane of the lens assembly, for transmitting the light emitted by the illumination system to the lens assembly, a positive pattern being arranged on the first marking plate to diffract the light, and the first marking plate being configured to form an image on the image plane of the lens assembly; a second marking plate, located on the image plane of the lens assembly, for transmitting the light transmitted through the lens assembly to the image receiving element; the image receiving element is configured to form a moiré pattern for determining the relative position of the first marking plate and the second marking plate based on the light, and a negative pattern is provided on the second marking plate; The positive pattern includes a plurality of first graphic units arranged at intervals, and a first point set formed by the marking points of each of the plurality of first graphic units is a Delone set; the negative pattern includes a plurality of second graphic units arranged at intervals, and a second point set formed by the marking points of each of the plurality of second graphic units is a Delone set; When the positive pattern is magnified m times and rotated 180°, the first point set covers the second point set of the negative pattern, or when the positive pattern is magnified m times, the first point set covers the second point set of the negative pattern; m>0; The first marking plate is used to be fixed on the first alignment member, the second marking plate is used to be fixed on the second alignment member, and the image receiving member is configured to form a moiré pattern for determining the relative positions of the first alignment member and the second alignment member based on the light.

2. The alignment device according to claim 1, characterized in that The lens assembly comprises: a first convex lens or lens group; and A second convex lens or lens group, the light passes through the first convex lens or lens group and the second convex lens or lens group in sequence.

3. The alignment device according to claim 2, characterized in that: The lens assembly further comprises an aperture stop, which is used to transmit the light passing through the first convex lens or lens group to the second convex lens or lens group.

4. The alignment device according to claim 1, characterized in that The lighting system comprises: A light source for emitting light; The convex lens or lens group is used to transmit the light emitted by the light source to the lens assembly so that the light is evenly irradiated onto the first marking plate.

5. The alignment device according to claim 1, characterized in that: The first point set or the second point set includes at least some points on the spiral line.

6. The alignment device according to claim 5, characterized in that The spiral is a Vogel spiral.

7. The alignment device according to claim 1, characterized in that: The first point set or the second point set is a set of at least some of the vertices of each figure in a Penrose quasicrystal pattern, a set of at least some of the vertices of each figure in a quasicrystal pattern obtained by a Voronoi map algorithm, a set of at least some of the vertices of each figure in a rotationally symmetric two-dimensional quasicrystal pattern, or a set of dual vertices obtained by a Voronoi map algorithm.

8. The alignment device according to claim 1, characterized in that The first graphic unit includes a circle, and the center of the circle is used as a marking point. The second graphic unit includes a circle, and the center of the circle is used as a marking point.

9. An alignment method, characterized in that: include: Acquire a moiré pattern using the alignment device according to any one of claims 1 to 8; Determining a first centroid position of the moiré pattern; Determining a first displacement corresponding to the first center of gravity position based on a mapping relationship between the center of gravity position and the displacement; The relative positions of the first marking plate and the second marking plate are adjusted based on the first displacement amount.

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