Nanoimprint alignment process and apparatus
By acquiring and processing images from the alignment camera in a nanoimprint alignment system, using sub-images to determine the plane angle and mounting tilt angle, and calculating the alignment deviation between the wafer and the template, the high cost and complexity issues of existing technologies are solved, achieving simplified and precise alignment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 张江国家实验室
- Filing Date
- 2025-01-22
- Publication Date
- 2026-07-24
AI Technical Summary
In nanoimprint alignment systems, existing methods require complex calibration devices and high costs to obtain camera parameters to achieve precise alignment between the wafer and the template, resulting in a complex and costly alignment process.
By acquiring images taken by the aligned camera, extracting the first and second sub-images, and using these sub-images to determine the plane angle, mounting tilt angle, and offset distance between the camera coordinate system and the specified coordinate system, the coordinates of the second alignment mark in the specified coordinate system are calculated, simplifying the alignment process between the wafer and the template and reducing alignment costs.
It achieves precise alignment between wafers and templates, simplifies the alignment method, reduces alignment costs, and avoids the need for complex calibration devices and high costs.
Smart Images
Figure CN122449862A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of chip technology, and in particular to a nanoimprint alignment processing method and apparatus. Background Technology
[0002] In nanoimprint alignment systems, based on interference moiré alignment technology, the alignment camera needs to be mounted at a Litterrow angle. To achieve precise alignment between the wafer and the template, the positions of the marker points on the wafer in the camera coordinate system need to be transformed to their positions in the world coordinate system.
[0003] To establish the coordinate relationship between the marker point in the camera coordinate system and the world coordinate system, the existing method is to obtain the geometric model parameters of the camera imaging, i.e., the camera parameters, and then perform coordinate transformations based on the camera parameters.
[0004] Camera parameters are generally obtained through experiments or calculations. Coordinate transformation based on camera parameters requires complex calibration equipment, which is costly and the methods for coordinate transformation are relatively complicated. Summary of the Invention
[0005] This application provides a nanoimprint alignment processing method and apparatus for achieving precise alignment between wafers and templates, simplifying the alignment method and reducing alignment costs.
[0006] In a first aspect, embodiments of this application provide a nanoimprint alignment processing method, which can be executed by a nanoimprint alignment processing device. The method includes: acquiring an image obtained by an alignment camera capturing images of a template and a wafer stacked together during the nanoimprinting process, wherein a first alignment mark is provided on the lower surface of the template and a second alignment mark is provided on the upper surface of the wafer; the first alignment mark and the second alignment mark correspond to each other; extracting a first sub-image and a second sub-image from the image, wherein the first sub-image includes the first alignment mark and the second sub-image includes the second alignment mark; and determining the plane of the camera coordinate system and the plane of the specified coordinate system based on the first sub-image. Plane angle; based on the coordinates of the second alignment mark in the camera coordinate system, the plane angle, the mounting tilt angle, and the offset distance, calculate the coordinates of the second alignment mark in the specified coordinate system; the mounting tilt angle is the angle between the lens of the alignment camera and the vertical direction; the offset distance is the visual offset length of the second alignment mark from the alignment camera's visual perspective when there is a gap between the template and the wafer, caused by the refraction of the incident light emitted by the alignment camera, resulting in a change in the propagation path; based on the coordinates of the second alignment mark in the specified coordinate system and the coordinates of the first alignment mark in the specified coordinate system, determine the alignment deviation between the wafer and the template.
[0007] Using the above method, a first sub-image and a second sub-image are obtained by extracting images captured by the alignment camera. The coordinates of the second alignment mark in the camera coordinate system are determined based on the second sub-image. These coordinates are then converted to coordinates in a specified coordinate system. Finally, the wafer alignment deviation is determined based on the coordinates of the second and first alignment marks in the specified coordinate system. In this way, the relationship between the marker points in the camera coordinate system and the specified coordinate system can be obtained through coordinate transformation. This eliminates the need for camera parameters and additional calibration devices, simplifying the wafer-template alignment method and reducing alignment costs.
[0008] In one possible implementation, determining the plane angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system based on the first sub-graph includes: determining two first alignment mark points in the first alignment marks, wherein the line connecting the two first alignment mark points is parallel to the x-axis of the specified coordinate system; and taking the angle between the line connecting the two first alignment mark points in the camera coordinate system and the x-axis of the camera coordinate system as the plane angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system.
[0009] By using the above method, the angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system can be determined by performing image processing on the first sub-image, thus simplifying the process of determining the angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system.
[0010] In one possible implementation, the mounting tilt angle is determined as follows: three second alignment mark points are determined from the second alignment marks, the three second alignment mark points not being on the same line; a first vector and a second vector of the three second alignment mark points in the camera coordinate system, and a third vector and a fourth vector of the three second alignment mark points in the specified coordinate system are determined respectively; two second alignment mark points in the first vector and two second alignment mark points in the third vector are the same two alignment mark points, and two second alignment mark points in the second vector and two second alignment mark points in the fourth vector are the same two second alignment mark points; the mounting tilt angle is calculated based on the first vector, the second vector, the third vector, and the fourth vector.
[0011] Using the method described above, four vectors are constructed using the coordinates of the three second alignment markers in the camera coordinate system and their coordinates in the specified coordinate system. The mounting angle of the alignment camera is then calculated using these vectors. This allows for the precise determination of the camera's mounting angle.
[0012] In one possible implementation, the installation tilt angle is calculated based on the first vector, the second vector, the third vector, and the fourth vector, including: the installation tilt angle is the inverse cosine function value determined by the modulus of the third vector, the modulus of the second vector, the modulus of the first vector, and the modulus of the fourth vector.
[0013] In one possible implementation, calculating the coordinates of a marker point of the second alignment mark in the specified coordinate system based on the coordinates of the second alignment mark in the camera coordinate system, the plane angle, the mounting tilt angle, and the offset distance includes: for any marker point in the second alignment mark, converting the coordinates of the marker point in the camera coordinate system into three-dimensional coordinates; constructing a first transformation matrix based on the mounting tilt angle, the first transformation matrix representing the transformation relationship between the plane of the camera coordinate system and the plane of the specified coordinate system; constructing a second transformation matrix based on the plane angle, the second transformation matrix representing the rotation relationship between the camera coordinate system and the specified coordinate system; constructing a third transformation matrix based on the offset distance, the third transformation matrix representing the offset relationship between the coordinates of the marker point in the camera coordinate system and the coordinates in the specified coordinate system; and calculating the three-dimensional coordinates of the marker point in the specified coordinate system based on the first transformation matrix, the second transformation matrix, the third transformation matrix, and the three-dimensional coordinates of the marker point in the camera coordinate system.
[0014] In one possible implementation, the first alignment mark and the second alignment mark are rectangles composed of multiple gratings, and any mark point is the center point of any rectangle.
[0015] Using the above method, the first alignment mark and the second alignment mark can be set flexibly, and the mark points can also be set flexibly.
[0016] In one possible implementation, the offset distance is determined by: obtaining the vertical distance between the lower surface of the template and the upper surface of the wafer; and calculating the offset distance based on the mounting angle and the vertical distance.
[0017] Secondly, embodiments of this application provide a nanoimprint alignment processing apparatus, the apparatus comprising: an acquisition module, configured to acquire images obtained by an alignment camera capturing images of a template and a wafer stacked together during the nanoimprinting process, wherein a first alignment mark is provided on the lower surface of the template and a second alignment mark is provided on the upper surface of the wafer; the first alignment mark and the second alignment mark correspond to each other; an extraction module, configured to extract a first sub-image and a second sub-image from the images, wherein the first sub-image includes the first alignment mark and the second sub-image includes the second alignment mark; and a processing module, configured to determine the plane angle between the plane of the camera coordinate system and the plane of the specified coordinate system based on the first sub-image. The calculation module is used to calculate the coordinates of the second alignment mark in a specified coordinate system based on the coordinates of the second alignment mark in the camera coordinate system, the plane angle, the mounting tilt angle, and the offset distance; the mounting tilt angle is the angle between the lens of the alignment camera and the vertical direction, and the offset distance is the visual offset of the second alignment mark from the alignment camera's visual angle when there is a gap between the template and the wafer, caused by the refraction of the incident light emitted by the alignment camera, which changes the propagation path; the determination module is used to determine the alignment deviation between the wafer and the template based on the coordinates of the second alignment mark in the specified coordinate system and the coordinates of the first alignment mark in the specified coordinate system.
[0018] In one possible implementation, the processing module is specifically used to: determine two first alignment mark points in the first alignment mark, wherein the line connecting the two first alignment mark points is parallel to the x-axis of the specified coordinate system; and take the angle between the line connecting the two first alignment mark points in the camera coordinate system and the x-axis of the camera coordinate system as the plane angle between the plane of the camera coordinate system and the plane of the specified coordinate system.
[0019] In one possible implementation, the determining module is further configured to: determine three second alignment mark points from the second alignment marks, the three second alignment mark points not being on the same line; determine a first vector and a second vector of the three second alignment mark points in the camera coordinate system, and a third vector and a fourth vector of the three second alignment mark points in the specified coordinate system; two second alignment mark points in the first vector are the same as two second alignment mark points in the third vector, and two second alignment mark points in the second vector are the same as two second alignment mark points in the fourth vector; the calculation module is further configured to: calculate the mounting tilt angle based on the first vector, the second vector, the third vector, and the fourth vector.
[0020] In one possible implementation, the installation tilt angle is the inverse cosine function value of the magnitudes of the third vector, the second vector, the first vector, and the fourth vector.
[0021] In one possible implementation, the calculation module is specifically configured to: convert the coordinates of any marker point in the second alignment marks into three-dimensional coordinates in the camera coordinate system; construct a first transformation matrix based on the mounting tilt angle, the first transformation matrix representing the transformation relationship between the plane of the camera coordinate system and the plane of the specified coordinate system; construct a second transformation matrix based on the plane angle, the second transformation matrix representing the rotation relationship between the camera coordinate system and the specified coordinate system; construct a third transformation matrix based on the offset distance, the third transformation matrix representing the offset relationship between the coordinates of the marker point in the camera coordinate system and the coordinates in the specified coordinate system; and calculate the three-dimensional coordinates of the marker point in the specified coordinate system based on the first transformation matrix, the second transformation matrix, the third transformation matrix, and the three-dimensional coordinates of the marker point in the camera coordinate system.
[0022] In one possible implementation, the first alignment mark and the second alignment mark are rectangles composed of multiple gratings, with any mark point being the center point of any rectangle.
[0023] In one possible implementation, the acquisition module is further configured to acquire the vertical distance between the lower surface of the template and the upper surface of the wafer; the calculation module is further configured to calculate the offset distance based on the mounting tilt angle and the vertical distance.
[0024] Thirdly, embodiments of this application also provide a nanoimprint alignment processing device, the device including a memory and a processor, the memory being used to store computer programs or instructions; the processor being used to invoke the computer programs or instructions stored in the memory to execute the method as in any possible implementation of the first aspect.
[0025] Fourthly, embodiments of this application provide a computer-readable storage medium storing instructions that, when read and executed by a computer, cause the computer to perform a method as described in any possible implementation of the first aspect.
[0026] Fifthly, embodiments of this application provide a computer program product storing instructions that, when read and executed by a computer, cause the computer to perform the method in any possible implementation of the first aspect described above. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a schematic flowchart of a nanoimprint alignment processing method provided in an embodiment of this application;
[0029] Figure 2 A schematic diagram of a nanoimprint alignment system provided in an embodiment of this application;
[0030] Figure 3 A schematic diagram of a first alignment mark in the world coordinate system provided in an embodiment of this application;
[0031] Figure 4 A schematic diagram of a first alignment mark in a camera coordinate system provided in an embodiment of this application;
[0032] Figure 5 A schematic diagram of a planar included angle provided for an embodiment of this application;
[0033] Figure 6 A schematic diagram of a second alignment mark in the world coordinate system provided in an embodiment of this application;
[0034] Figure 7 A schematic diagram of a second alignment mark in a camera coordinate system provided in an embodiment of this application;
[0035] Figure 8 A schematic diagram of the internal modules of a nanoimprint alignment processing device 8000 provided in an embodiment of this application;
[0036] Figure 9 This is a schematic diagram of a nanoimprint alignment processing device 9000 provided in an embodiment of this application. Detailed Implementation
[0037] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0038] Nanoimprint lithography is used to fabricate chips. Simply put, it involves etching raised / recessed circuit patterns onto a template, uniformly coating a layer of photoresist onto the wafer surface, and then pressing the template onto the wafer after aligning it with the photoresist-coated wafer. This imprints the circuit patterns from the template onto the photoresist. To ensure accurate superposition of multiple circuit patterns, the alignment between the template and the wafer must be extremely precise.
[0039] Based on this, embodiments of this application provide a nanoimprint alignment method, which provides a simple way to accurately align a wafer with a template.
[0040] Figure 1 This is a schematic flowchart illustrating a nanoimprint alignment method provided in an embodiment of this application. This flowchart can be executed by a nanoimprint alignment device, such as... Figure 1 As shown, the process includes the following steps:
[0041] Step 101: The nanoimprint alignment processing device acquires images of the template and wafer stacked together during the nanoimprinting process using an alignment camera.
[0042] Nanoimprint alignment devices can be intelligent devices such as computers and small servers. An alignment camera is an essential component in nanoimprint methods. Based on interference moiré alignment technology, the alignment camera needs to be mounted at a Littoral angle. The Littoral angle is a commonly used tilt angle in optical systems; its magnitude depends on the period of the grating and the wavelength of the light wave, and can be calculated using the grating equation. Figure 2 This is a schematic diagram of a nanoimprint alignment system provided in an embodiment of this application. Figure 2 As can be seen, the nanoimprint alignment system includes a camera, a template, and a wafer. The camera is mounted at an angle, and there is a certain gap between the template and the wafer. This gap is used to coat the wafer with photoresist and to flexibly move the wafer, achieving precise transfer of the template's nanopattern. In the nanoimprint alignment system, the template can remain stationary, while the wafer can be placed on a stage. Moving the stage moves the wafer. The camera includes a laser illumination source. The light emitted by the laser illumination source serves as the incident light, passing through the template and then illuminating the wafer. Because the template material is uniform, the angle at which the light enters the template is the same as the angle at which the light exits the template.
[0043] A first alignment mark is provided on the lower surface of the template, and a second alignment mark is provided on the upper surface of the wafer. The first alignment mark corresponds to the second alignment mark. Both the first and second alignment marks are formed by a grating structure. The template is transparent or nearly transparent. By moving the workpiece stage, the second alignment mark on the upper surface of the wafer and the first alignment mark on the lower surface of the template can be simultaneously captured by the alignment camera. Typically, the second alignment mark on the upper surface of the wafer can be located at the edge of the wafer, and photoresist is coated in the middle area of the upper surface of the wafer. The shapes of the first and second alignment marks are the shapes formed by the grating structure, and can be rectangular or rhomboid. The shapes of the first and second alignment marks can also be different, and this application does not impose specific limitations on them.
[0044] Step 102: The nanoimprint alignment processing device extracts a first sub-image and a second sub-image from the image. The first sub-image includes a first alignment mark, and the second sub-image includes a second alignment mark.
[0045] After the camera captures an image of the stacked template and wafer, the image is sent to a nanoimprint alignment processing device. The device extracts a first sub-image and a second sub-image from the image. The first sub-image includes a first alignment mark on the lower surface of the template, and the second sub-image includes a second alignment mark on the upper surface of the wafer. It should be noted that the first alignment mark in the first sub-image is a pattern formed by the first alignment mark, and the second alignment mark in the second sub-image is a pattern formed by the second alignment mark. Optionally, the first alignment mark can be a rectangle formed by a grating, and the second alignment mark can be a rectangle with a notched corner formed by a grating. Based on the shapes of the first and second alignment marks, the first and second sub-images can be extracted relatively easily.
[0046] Step 103: The nanoimprint alignment processing device determines the plane angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system based on the first sub-image.
[0047] For example, the specified coordinate system can be the world coordinate system or other types of coordinate systems. In this embodiment, the specified coordinate system is the world coordinate system. The template is placed horizontally in space, with the center point of the template as the origin. The x-axis and y-axis are constructed in the horizontal and vertical directions, respectively. The world coordinate system is constructed using the origin, x-axis, and y-axis. The world coordinate system represents the position of the target object in the real world. The camera coordinate system is a coordinate system established on the camera, with the optical center as the origin. The plane perpendicular to the optical axis is used as the plane containing the x-axis and y-axis. The camera coordinate system represents the position of the target object in the camera's shooting direction.
[0048] For example, Figure 3 This application provides a schematic diagram of a first alignment mark in the world coordinate system, from which... Figure 3As can be seen, the first alignment mark is three rectangles formed by the grating. Figure 4 This is a schematic diagram of a first alignment mark in the camera coordinate system provided in an embodiment of this application. Figure 3 Includes three rectangular alignment marks: 301, 302, and 303. Figure 4 The image includes three rectangular alignment marks: 401, 402, and 403. The numbers 301, 302, 303, 401, 402, and 403 are merely labels for the rectangles; the actual alignment marks do not include numbers. Because the alignment camera is mounted at an angle, the incident light rays emitted by the camera are not perpendicular to the plane containing the first alignment mark. Therefore, the first alignment mark captured by the alignment camera differs from the actual first alignment mark in the world coordinate system. The image captured by the alignment camera is an image of the first and second alignment marks in the camera coordinate system; the first sub-image is the image of the first alignment mark in the camera coordinate system.
[0049] Based on the first sub-image, the angle between the plane containing the camera coordinate system and the plane containing the world coordinate system is determined. Specifically, the first sub-image is converted into a grayscale image; the grayscale image is processed by Gaussian filtering and other methods to reduce image noise; the contour of the first alignment mark is extracted using threshold segmentation and other methods; the minimum bounding rectangle of the target contour is established, and the center point and rotation angle of the minimum bounding rectangle are obtained, thereby obtaining the rotation angle 'a', which is the angle between the plane containing the camera coordinate system and the plane containing the world coordinate system.
[0050] Optionally, image processing is performed on the first sub-image to obtain the plane angle between the plane containing the camera coordinate system and the plane containing the world coordinate system, including: determining two first alignment mark points in the first alignment mark, wherein the line connecting the two first alignment mark points is parallel to the x-axis of the world coordinate system; and taking the angle between the line connecting the two first alignment mark points in the camera coordinate system and the x-axis of the camera coordinate system as the plane angle between the plane containing the camera coordinate system and the plane containing the world coordinate system.
[0051] Following the example above, the first alignment mark point is determined. This first alignment mark point can be the center point of 301 and 302, the upper left corner of 301 and 302, or any other two mark points. The line connecting the two first alignment mark points should be parallel to the x-axis of the world coordinate system. The specific location of the first alignment mark point is not specifically limited. This embodiment uses the center point of 301 and 302 as the first alignment mark point as an example. Figure 5 This is a schematic diagram of a plane angle provided in an embodiment of this application. Since the line connecting the two first alignment marks is parallel to the world coordinate system, the angle between the line connecting the two first alignment marks in the camera coordinate system and the x-axis of the camera coordinate system is the plane angle between the plane where the camera coordinate system is located and the plane where the world coordinate system is located. Figure 5 The acute angle between the two dashed lines is the angle between the plane containing the camera coordinate system and the plane containing the world coordinate system.
[0052] Step 104: The nanoimprint alignment processing device calculates the coordinates of the second alignment mark in the specified coordinate system based on the coordinates of the second alignment mark in the camera coordinate system, the plane angle, the mounting tilt angle, and the offset distance.
[0053] The second alignment mark can be a rectangle composed of gratings. For any point within the rectangle, the coordinates of that point in the world coordinate system are calculated based on its coordinates in the camera coordinate system, the plane angle, the mounting tilt angle, and the offset distance. The mounting tilt angle is the angle between the camera lens and the vertical direction. The offset distance is the visual offset of the second alignment mark from the camera's perspective when there is a gap between the template and the wafer, caused by the refraction of incident light emitted from the camera, which alters the propagation path.
[0054] The installation tilt angle is the Littoral angle, but deviations may occur during actual installation. Therefore, the installation tilt angle can also be determined as follows: Three second alignment mark points are determined from the second alignment marks. These three second alignment mark points are not on the same line in the world coordinate system. The first and second vectors of the three second alignment mark points in the camera coordinate system, as well as the third and fourth vectors of the three second alignment mark points in the world coordinate system, are determined respectively. The first vector corresponds to the third vector, and the second vector corresponds to the fourth vector. The installation tilt angle is calculated based on the first, second, third, and fourth vectors.
[0055] Specifically, Figure 6 This is a schematic diagram of a second alignment mark in the world coordinate system provided in an embodiment of this application. Figure 7 This is a schematic diagram of a second alignment mark in a camera coordinate system provided in an embodiment of this application. In this embodiment, the second alignment mark is also rectangular. Alternatively, it can be other shapes. Figure 6 DEF and Figure 7 In the alignment mark, 'def' represents the center point of each rectangle, which is not included in the actual alignment mark. The three second alignment mark points determined from the second alignment mark can be the center points of each rectangle, provided that the three second alignment mark points are not on the same line in the world coordinate system. Figure 7 The coordinates of the three second alignment marker points (def) in the diagram can determine the first and second vectors. Since the second subgraph includes the second alignment markers, the center points of the three second alignment markers can be determined from the second subgraph. For example, the first vector is... The second vector is according to Figure 6The three second alignment markers DEF determine the third and fourth vectors. Since a vector represents the relative position between two points, the third vector can be determined even without knowing the coordinates of DEF in the world coordinate system, only knowing the relative positions and sizes of the three second alignment markers. and the fourth vector The installation tilt angle is calculated based on the first, second, third, and fourth vectors.
[0056] Optionally, the offset distance can also be determined as follows: obtain the vertical distance between the lower surface of the template and the upper surface of the wafer, and calculate the offset distance based on the mounting angle and the vertical distance. Specifically, the vertical distance between the lower surface of the template and the upper surface of the wafer is... Figure 2 The offset distance s is obtained from the installation tilt angle θ and the vertical distance Gap, where s = Gap * tanθ.
[0057] Based on the coordinates, plane angle, mounting tilt angle, and offset distance of the second alignment mark in the camera coordinate system, the coordinates of the marker point of the second alignment mark in the world coordinate system are calculated. This includes: for any marker point in the second alignment mark, converting the coordinates of the marker point in the camera coordinate system into three-dimensional coordinates; constructing a first transformation matrix based on the mounting tilt angle, which represents the transformation relationship between the plane of the camera coordinate system and the plane of the world coordinate system; constructing a second transformation matrix based on the plane angle, which represents the rotation relationship between the camera coordinate system and the world coordinate system; and constructing a third transformation matrix based on the offset distance, which represents the offset relationship between the coordinates of the marker point in the camera coordinate system and its coordinates in the world coordinate system. Based on the first transformation matrix, the second transformation matrix, the third transformation matrix, and the three-dimensional coordinates of the marker point in the camera coordinate system, the three-dimensional coordinates of the marker point in the world coordinate system are calculated.
[0058] Optionally, for any marker point in the second alignment marks, the coordinates of the marker point in the camera coordinate system are determined to be (x', y'), and the coordinates of the marker point in the camera coordinate system are converted into three-dimensional coordinates (x', y', 1). A first transformation matrix is constructed based on the installation tilt angle θ. Construct the second transformation matrix based on the plane angle α. Construct a third transformation matrix based on the offset distance s. 3D coordinates of the marker point in the world coordinate system S 晶圆 =RP-M. Thus, the coordinates in the world coordinate system can be calculated from the coordinates of any marker point in the second alignment mark in the camera coordinate system.
[0059] Step 105: The nanoimprint alignment processing device determines the alignment deviation between the wafer and the template based on the coordinates of the second alignment mark in the specified coordinate system and the coordinates of the first alignment mark in the specified coordinate system.
[0060] Specifically, the first alignment mark is etched on the lower surface of the template and remains stationary, meaning the coordinates of the first alignment mark in the world coordinate system are known. The second alignment mark is etched on the upper surface of the wafer, and the second alignment mark corresponds one-to-one with the first alignment mark. After calculating the coordinates of the second alignment mark in the world coordinate system according to step 104, the alignment deviation between the wafer and the template is determined based on the coordinates of the second alignment mark in the world coordinate system and the coordinates of the first alignment mark in the world coordinate system.
[0061] Since a plane can be determined based on at least three points, the embodiments of this application can calculate the coordinates of the three second alignment mark points DEF in the world coordinate system. Based on the coordinates of the three second alignment mark points DEF in the world coordinate system and the coordinates of the three first alignment mark points in the world coordinate system, the alignment deviation between the wafer and the template is determined. Since there is a one-to-one correspondence between the first alignment mark and the second alignment mark, there is a one-to-one correspondence between the first alignment mark point and the second alignment mark point. For example, if the first alignment mark point is the center of the first alignment mark, the center point of rectangle 301 is A, the center point of rectangle 302 is B, and the center point of rectangle 303 is C, then the second alignment mark point D corresponds to the first alignment mark point A, the second alignment mark point E corresponds to the first alignment mark point B, and the second alignment mark point F corresponds to the first alignment mark point C.
[0062] To ensure precise alignment between the wafer and the template, the coordinates of the second alignment mark on the wafer and the first alignment mark on the template must be consistent in the world coordinate system. Based on the coordinates of the three second alignment marks (DEF) and the three first alignment marks (ABC) in the world coordinate system, the required distance and rotation angle of the wafer are determined. The workpiece stage is then controlled according to these parameters to move the wafer to the precise position.
[0063] Optionally, since the template may deform due to heat or compression, alignment marks can be set in multiple areas of the template. For example, if the template is rectangular, alignment marks can be set in the four corner areas of the template. By aligning the wafer with the alignment marks in the four corner areas, the alignment accuracy between the wafer and the template can be improved.
[0064] Figure 8 A schematic diagram of the internal modules of a nanoimprint alignment processing device 8000 provided in an embodiment of this application is shown below. Figure 8As shown, the device may include: an acquisition module 801, an extraction module 802, a processing module 803, a calculation module 804, and a determination module 805. Optionally, it may also include a storage module for storing computer instructions or programs, and the processing module 803 may call the computer instructions or programs stored in the storage module.
[0065] The acquisition module 801 is used to acquire images of a template and a wafer stacked together during the nanoimprinting process, captured by an alignment camera. The lower surface of the template has a first alignment mark, and the upper surface of the wafer has a second alignment mark; the first alignment mark corresponds to the second alignment mark. The extraction module 802 is used to extract a first sub-image and a second sub-image from the images. The first sub-image includes the first alignment mark, and the second sub-image includes the second alignment mark. The processing module 803 is used to determine the plane angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system based on the first sub-image. The calculation module 804 is used to calculate the angle between the second alignment mark and the first sub-image. The coordinates of the alignment mark in the camera coordinate system, the included angle of the plane, the mounting tilt angle, and the offset distance are used to calculate the coordinates of the second alignment mark in the specified coordinate system. The mounting tilt angle is the angle between the lens of the alignment camera and the vertical direction. The offset distance is the visual offset length of the second alignment mark from the perspective of the alignment camera when there is a gap between the template and the wafer, caused by the refraction of the incident light emitted by the alignment camera, which changes the propagation path. The determination module 805 is used to determine the alignment deviation between the wafer and the template based on the coordinates of the second alignment mark in the specified coordinate system and the coordinates of the first alignment mark in the specified coordinate system.
[0066] In one possible implementation, the processing module 803 is specifically used to: determine two first alignment mark points in the first alignment mark, wherein the line connecting the two first alignment mark points is parallel to the x-axis of the specified coordinate system; and take the angle between the line connecting the two first alignment mark points in the camera coordinate system and the x-axis of the camera coordinate system as the plane angle between the plane of the camera coordinate system and the plane of the specified coordinate system.
[0067] In one possible implementation, the determining module 805 is further configured to: determine three second alignment mark points from the second alignment marks, the three second alignment mark points not being on the same line; determine a first vector and a second vector of the three second alignment mark points in the camera coordinate system, and a third vector and a fourth vector of the three second alignment mark points in the specified coordinate system; two second alignment mark points in the first vector are the same as two second alignment mark points in the third vector, and two second alignment mark points in the second vector are the same as two second alignment mark points in the fourth vector; the calculation module 804 is further configured to: calculate the mounting tilt angle based on the first vector, the second vector, the third vector, and the fourth vector.
[0068] In one possible implementation, the installation tilt angle is the inverse cosine function value of the magnitudes of the third vector, the second vector, the first vector, and the fourth vector.
[0069] In one possible implementation, the calculation module 804 is specifically configured to: convert the coordinates of any marker point in the second alignment marks into three-dimensional coordinates in the camera coordinate system; construct a first transformation matrix based on the installation tilt angle, the first transformation matrix representing the transformation relationship between the plane of the camera coordinate system and the plane of the specified coordinate system; construct a second transformation matrix based on the plane angle, the second transformation matrix representing the rotation relationship between the camera coordinate system and the specified coordinate system; construct a third transformation matrix based on the offset distance, the third transformation matrix representing the offset relationship between the coordinates of the marker point in the camera coordinate system and the coordinates in the specified coordinate system; and calculate the three-dimensional coordinates of the marker point in the specified coordinate system based on the first transformation matrix, the second transformation matrix, the third transformation matrix, and the three-dimensional coordinates of the marker point in the camera coordinate system.
[0070] In one possible implementation, the first alignment mark and the second alignment mark are multiple rectangles formed by a grating, and any mark point is the center point of any rectangle.
[0071] In one possible implementation, the acquisition module 801 is further configured to acquire the vertical distance between the lower surface of the template and the upper surface of the wafer; the calculation module 804 is further configured to calculate the offset distance based on the mounting tilt angle and the vertical distance.
[0072] Figure 9 A schematic diagram of a nanoimprint alignment processing device 9000 provided in this application embodiment is shown below. Figure 9As shown, it includes at least one processor 901 and a memory 902 connected to at least one processor 901. In this embodiment, the specific connection medium between the processor 901 and the memory 902 is not limited. Figure 9 Taking the connection between processor 901 and memory 902 via a bus as an example, the bus can be divided into address bus, data bus, control bus, etc.
[0073] In this embodiment of the application, the memory 902 stores instructions that can be executed by at least one processor 901. By executing the instructions stored in the memory 902, the at least one processor 901 can implement the steps of the above-described nanoimprint alignment process.
[0074] The processor 901 is the control center of the computer device, capable of connecting various parts of the device via various interfaces and lines. It performs resource configuration by running or executing instructions stored in the memory 902 and accessing data stored in the memory 902. Optionally, the processor 901 may include one or more processing units. The processor 901 may integrate an application processor and a modem processor. The application processor primarily handles the operating system, user interface, and applications, while the modem processor primarily handles wireless communication. It is understood that the modem processor may not be integrated into the processor 901. In some embodiments, the processor 901 and the memory 902 may be implemented on the same chip; in other embodiments, they may be implemented on separate chips.
[0075] The processor 901 can be a general-purpose processor, such as a central processing unit (CPU), digital signal processor, application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.
[0076] Memory 902, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. Memory 902 may include at least one type of storage medium, such as flash memory, hard disk, multimedia card, card-type memory, random access memory (RAM), static random access memory (SRAM), programmable read-only memory (PROM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic storage, magnetic disk, optical disk, etc. Memory 902 can be any other medium capable of carrying or storing desired program code in the form of instructions or data structures that can be accessed by a computer, but is not limited thereto. In the embodiments of this application, memory 902 can also be a circuit or any other device capable of implementing storage functions for storing program instructions and / or data.
[0077] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0078] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0079] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0080] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0081] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.
Claims
1. A nanoimprint alignment processing method, characterized in that, The method includes: The image is obtained by an alignment camera capturing images of a template and a wafer stacked together during the nanoimprinting process. The lower surface of the template is provided with a first alignment mark, and the upper surface of the wafer is provided with a second alignment mark; the first alignment mark corresponds to the second alignment mark. Extract a first sub-image and a second sub-image from the image, wherein the first sub-image includes the first alignment mark and the second sub-image includes the second alignment mark; Determine the angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system based on the first sub-graph; Based on the coordinates of the second alignment mark in the camera coordinate system, the plane angle, the mounting tilt angle, and the offset distance, the coordinates of the second alignment mark in the specified coordinate system are calculated; the mounting tilt angle is the angle between the lens of the alignment camera and the vertical direction; the offset distance is the visual offset length of the second alignment mark from the perspective of the alignment camera when there is a gap between the template and the wafer, caused by the refraction of the incident light emitted by the alignment camera, which changes the propagation path. The alignment deviation between the wafer and the template is determined based on the coordinates of the second alignment mark in the specified coordinate system and the coordinates of the first alignment mark in the specified coordinate system.
2. The method according to claim 1, characterized in that, Determining the angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system based on the first sub-graph includes: Two first alignment mark points are determined in the first alignment mark, and the line connecting the two first alignment mark points is parallel to the x-axis of the specified coordinate system in the specified coordinate system; The angle between the line connecting the two first alignment marks in the camera coordinate system and the x-axis of the camera coordinate system is taken as the plane angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system.
3. The method according to claim 1, characterized in that, The installation tilt angle is determined in the following way: Three second alignment mark points are determined from the second alignment mark, and the three second alignment mark points are not on the same line; The first and second vectors of the three second alignment mark points in the camera coordinate system are determined respectively, as well as the third and fourth vectors of the three second alignment mark points in the specified coordinate system; the two second alignment mark points in the first vector are the same as the two second alignment mark points in the third vector, and the two second alignment mark points in the second vector are the same as the two second alignment mark points in the fourth vector. The installation tilt angle is calculated based on the first vector, the second vector, the third vector, and the fourth vector.
4. The method according to claim 3, characterized in that, The installation tilt angle is calculated based on the first vector, the second vector, the third vector, and the fourth vector, including: The installation tilt angle is the inverse cosine function value determined by the modulus of the third vector, the modulus of the second vector, the modulus of the first vector, and the modulus of the fourth vector.
5. The method according to claim 1, characterized in that, Based on the coordinates of the second alignment mark in the camera coordinate system, the included angle of the plane, the mounting tilt angle, and the offset distance, the coordinates of the mark point of the second alignment mark in the specified coordinate system are calculated, including: For any marker point in the second alignment marks, convert the coordinates of the marker point in the camera coordinate system into three-dimensional coordinates; A first transformation matrix is constructed based on the installation tilt angle. The first transformation matrix represents the transformation relationship between the projection of the plane containing the camera coordinate system onto the plane containing the specified coordinate system. A second transformation matrix is constructed based on the plane angle, and the second transformation matrix represents the rotational relationship between the camera coordinate system and the specified coordinate system; A third transformation matrix is constructed based on the offset distance. The third transformation matrix represents the offset relationship between the coordinates of the marker point in the camera coordinate system and its coordinates in the specified coordinate system. Based on the first transformation matrix, the second transformation matrix, the third transformation matrix, and the three-dimensional coordinates of the marker point in the camera coordinate system, calculate the three-dimensional coordinates of the marker point in the specified coordinate system.
6. The method according to any one of claims 1 to 5, characterized in that, The first alignment mark and the second alignment mark are multiple rectangles formed by gratings, and any mark point is the center point of any rectangle.
7. The method according to any one of claims 1 to 5, characterized in that, The offset distance is determined in the following manner: Obtain the vertical distance between the lower surface of the template and the upper surface of the wafer; The offset distance is calculated based on the installation tilt angle and the vertical distance.
8. A nanoimprint alignment processing device, characterized in that, The device includes: The acquisition module is used to acquire images of the template and wafer stacked together during the nanoimprinting process by the alignment camera. The lower surface of the template is provided with a first alignment mark, and the upper surface of the wafer is provided with a second alignment mark. The first alignment mark corresponds to the second alignment mark. An extraction module is used to extract a first sub-image and a second sub-image from the image, wherein the first sub-image includes the first alignment mark and the second sub-image includes the second alignment mark; The processing module determines the angle between the plane containing the camera coordinate system and the plane containing the specified coordinate system based on the first sub-image. The calculation module is used to calculate the coordinates of the second alignment mark in the specified coordinate system based on the coordinates of the second alignment mark in the camera coordinate system, the plane angle, the mounting tilt angle, and the offset distance; the mounting tilt angle is the angle between the lens of the alignment camera and the vertical direction; the offset distance is the visual offset length of the second alignment mark from the visual perspective of the alignment camera when there is a gap between the template and the wafer, caused by the refraction of the incident light emitted by the alignment camera, which changes the propagation path. The determination module is used to determine the alignment deviation between the wafer and the template based on the coordinates of the second alignment mark in the specified coordinate system and the coordinates of the first alignment mark in the specified coordinate system.
9. A nanoimprint alignment processing device, characterized in that, The device includes: Memory is used to store computer programs or instructions; A processor is configured to invoke a computer program or instructions stored in the memory to perform the method as described in any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when read and executed by a computer, cause the computer to perform the method as described in any one of claims 1 to 7.
11. A computer program product, characterized in that, The computer program product stores instructions that, when read and executed by a computer, cause the computer to perform the method as described in any one of claims 1 to 7.