A wafer position compensation alignment method, apparatus, device and storage medium

Abstract

This invention discloses a wafer position compensation alignment method, apparatus, device, and storage medium, relating to the field of semiconductor wafer inspection technology. The wafer position compensation alignment method includes: determining the eccentricity parameter of the wafer's geometric center relative to the mechanical center of the stage; determining the relative rotational deviation of the wafer using a graded alignment method based on the eccentricity parameter and at least two alignment marks of similar radial distance on the wafer; determining the target stage position for compensating and eliminating eccentricity and rotational errors according to the eccentricity parameter and rotational deviation; and controlling the stage to move to the target stage position to complete wafer alignment. This application can solve the dual errors of eccentricity and rotation caused by blue film attachment, and can improve the accuracy of wafer posture recovery and scanning success rate.

Description

Technical Field

[0001] This application relates to the field of semiconductor wafer inspection technology, specifically to a wafer position compensation alignment method, apparatus, device, and storage medium. Background Technology

[0002] In wafer dicing and subsequent processes, the blue iron ring film is widely used as a carrier for wafer transport. Especially after the dicing process, the wafer has been divided into individual dies, and the blue film plays a crucial role in supporting and fixing the die positions. Therefore, in the subsequent MDI (Macro Defect Inspection) visual inspection stage, the wafer under test is carried on the blue iron ring film and sent into the inspection equipment, rather than being transported directly as a bare die.

[0003] Due to uncertainties in blue film adhesion, wafers often encounter problems when entering AOI (Automatic Optical Inspection) or MDI systems. These problems include wafer eccentricity: the wafer center deviates from the center of the iron ring, causing a mismatch between the system's default coordinates and the actual wafer coordinates, resulting in incorrect scanning range; and wafer rotation deviation: the wafer's orientation rotates, causing the alignment marks to no longer appear in the expected field of view. See [link to documentation] for details. Figure 1 As shown.

[0004] In existing equipment, common methods for dealing with eccentricity and rotation include: expanding the alignment search area, increasing the camera's field of view, or using multi-level magnification to search for the mark, but the mark may still be completely invisible under large-angle rotation; or abandoning alignment and switching to blind scanning: scanning directly according to the mechanical center without performing precise alignment, but this method leads to large image stitching errors; some areas may not be scanned at all; subsequent AOI positioning will be inaccurate, making it unusable for measurement or defect review. Therefore, traditional methods cannot reliably solve the problem of large eccentricity + large rotation caused by blue film adhesion errors, often resulting in the problem of "alignment failure → inability to scan → equipment shutdown".

[0005] Furthermore, existing technologies typically assume that the wafer center coincides with or has a very small, negligible deviation from the rotation center of the stage machinery. However, in blue film wafer inspection, due to random eccentricity caused by manual film application, the wafer's geometric center... With platform mechanical center An unknown eccentricity vector exists. When the system controls the stage to rotate in order to correct the wafer angle deviation Δθ, the wafer will rotate around its center, causing non-linear positional shifts in the feature points (Mark points) on the wafer. This renders traditional alignment algorithms based on a single coordinate system ineffective, requiring a new global search, which greatly reduces detection efficiency. Summary of the Invention

[0006] This application provides a wafer position compensation alignment method, apparatus, device, and storage medium, which can solve the dual errors of eccentricity and rotation caused by blue film attachment, and improve the accuracy of wafer posture recovery and scanning success rate.

[0007] In a first aspect, embodiments of this application provide a wafer position compensation alignment method, the wafer position compensation alignment method comprising: Determine the eccentricity parameters of the wafer's geometric center relative to the mechanical center of the stage; Based on the aforementioned eccentricity parameters and at least two alignment marks distributed at similar radial distances on the wafer, a hierarchical alignment method is used to determine the relative rotational deviation of the wafer. Based on the eccentricity parameters and rotational deviation, determine the target stage position for compensating for and eliminating eccentricity and rotational errors; Control the stage to move to the target stage position to complete wafer alignment.

[0008] In conjunction with the first aspect, in one embodiment, determining the eccentricity parameter of the wafer's geometric center relative to the stage's mechanical center includes: Edge points are sampled in at least three non-collinear directions at the edge of the wafer. Based on the sampled edge points, a circle is fitted to determine the coordinates of the wafer's geometric center in the mechanical coordinate system of the stage, which are used as the eccentricity parameter.

[0009] In conjunction with the first aspect, in one embodiment, sampling edge points in at least three non-collinear directions of the wafer edge, performing circle fitting based on the sampled edge points, and determining the coordinates of the wafer's geometric center in the stage mechanical coordinate system includes: Multiple edge points were collected in the 0°, 120° and 240° regions at the wafer edge; Based on multiple edge points, the coordinates of the wafer's geometric center in the stage mechanical coordinate system are calculated using the least squares circle fitting algorithm.

[0010] In conjunction with the first aspect, in one embodiment, determining the relative rotational deviation of the wafer using a graded alignment method based on the eccentricity parameter and at least two alignment marks distributed at approximately the same radial distance on the wafer includes: After the stage is compensated based on the eccentricity parameters, the angle deviation between the actual position and the theoretical position of the first alignment mark in the inner circle region of the wafer is obtained by image recognition based on the first alignment mark, which is used as the coarse rotation deviation of the wafer. After the stage is compensated for the coarse rotational deviation, the actual position of the second alignment mark and the angular deviation of the theoretical position of the second alignment mark are obtained by image recognition based on the second alignment mark in the outer ring region of the wafer, which is used as the precise rotational deviation of the wafer.

[0011] In conjunction with the first aspect, in one implementation, it further includes: If the first alignment mark does not enter the field of view of image recognition, the stage is controlled to move the wafer, with the theoretically calculated position of the first alignment mark as the center, and moves according to a preset spiral trajectory. During the movement, images are continuously acquired until the first alignment mark is captured. The theoretical calculated position of the first alignment mark is the position of the first alignment mark in the wafer coordinate system after compensation based on the eccentricity parameter.

[0012] In conjunction with the first aspect, in one implementation, it further includes: Obtain the positional deviation between the actual imaging position of the alignment marker in the field of view and the center of the field of view; Based on the positional deviation, a fine-tuning command is generated to control the stage to move until the alignment mark is located in the center of the field of view.

[0013] In conjunction with the first aspect, in one implementation, based on the homogeneous transformation matrix Characterizing positional deviation based on homogeneous transformation matrix Characterizing rotational deviation based on homogeneous transformation matrix Characterizing eccentricity parameters; According to the formula: Calculate the position of the target platform ,in, These are the theoretical coordinates on the wafer relative to the wafer's geometric center.

[0014] Secondly, embodiments of this application provide a wafer position compensation and alignment device, the wafer position compensation and alignment device comprising: The compensation module is used to determine the eccentricity parameter of the wafer's geometric center relative to the mechanical center of the stage. The compensation module also determines the relative rotational deviation of the wafer based on the eccentricity parameter and at least two alignment marks that are radially distributed at similar distances on the wafer, using a graded alignment method. The calculation module determines the target stage position for compensating for and eliminating eccentricity and rotation errors based on the eccentricity parameters and rotation deviations. The control module is used to control the stage to move to the target stage position in order to complete the wafer alignment.

[0015] Thirdly, embodiments of this application provide a wafer position compensation and alignment device, the wafer position compensation and alignment device including a processor, a memory, and a wafer position compensation and alignment program stored in the memory and executable by the processor, wherein when the wafer position compensation and alignment program is executed by the processor, it implements the steps of the wafer position compensation and alignment method as described above.

[0016] Fourthly, embodiments of this application provide a computer-readable storage medium storing a wafer position compensation alignment program, wherein when the wafer position compensation alignment program is executed by a processor, it implements the steps of the wafer position compensation alignment method as described above.

[0017] The beneficial effects of the technical solutions provided in this application include: The wafer position compensation alignment method in this application determines the eccentricity parameter of the wafer's geometric center relative to the mechanical center of the stage; based on the eccentricity parameter and at least two alignment marks distributed radially at similar distances on the wafer, a graded alignment method is used to determine the relative rotational deviation of the wafer; according to the eccentricity parameter and the rotational deviation, a target stage position is determined to compensate for and eliminate eccentricity and rotational errors; and the stage is controlled to move to the target stage position to complete the wafer alignment.

[0018] Therefore, by determining the eccentricity parameter of the wafer's geometric center relative to the mechanical center of the stage, the translational eccentricity error caused by wafer placement can be effectively eliminated. Furthermore, based on at least two alignment marks distributed at similar radial distances, a hierarchical alignment method is adopted. The characteristic of the near-center mark, which has small displacement under rotation and is less likely to lose its field of view, is used to improve the initial capture success rate. At the same time, the characteristic of the far-center mark, which is sensitive to angular changes, is used to improve the calculation accuracy of rotational deviation, thus solving the contradiction that a single mark cannot simultaneously ensure alignment success rate and accuracy. Finally, the target stage position is determined and the motion is controlled based on the linkage of the eccentricity parameter and rotational deviation, realizing integrated compensation for eccentricity error and rotational error, which significantly improves the overall success rate, accuracy, and robustness of wafer alignment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the principle that eccentricity and rotation errors cause the Mark point to deviate from the camera's field of view. Figure 2 This is a schematic flowchart of an embodiment of the wafer position compensation alignment method of this application; Figure 3 This is the overall flowchart of this application; Figure 4 This is a hardware system architecture diagram of this application; Figure 5 This is a schematic diagram illustrating the edge sampling and fitting principle of this application; Figure 6 This is a schematic diagram comparing the displacement deviations of the inner and outer ring alignment marks of this application under the same rotation angle. Figure 7 This is a schematic diagram of the eccentric rotation compensation principle of this application; Figure 8The following is a timing diagram of the "prediction-correction" iteration of this application, where (a) is the prediction stage, (b) is the catch-up stage, and (c) is the correction stage; Figure 9 This is a schematic diagram of the coordinate system transformation logic in this application; Figure 10 This is a schematic diagram of the functional modules of an embodiment of the wafer position compensation alignment device of this application; Figure 11 This is a schematic diagram of the hardware structure of the wafer position compensation and alignment device involved in the embodiments of this application. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0022] In a first aspect, embodiments of this application provide a wafer position compensation alignment method.

[0023] In one embodiment, reference is made to Figure 2 , Figure 2 This is a schematic flowchart of the first embodiment of the wafer position compensation alignment method of this application. Figure 2 and Figure 3 As shown, the wafer position compensation alignment method includes: S1. Determine the eccentricity parameters of the wafer's geometric center relative to the mechanical center of the stage; See Figure 4 As shown, the system hardware involved in this embodiment includes an industrial camera, a controllable light source (dark field or bright field), a stage motion system, a motion control card, and a main control unit.

[0024] In step S1, edge points are sampled in at least three non-collinear directions of the wafer edge. Based on the sampled edge points, a circle is fitted to determine the coordinates of the wafer's geometric center in the stage mechanical coordinate system, which are used as the eccentricity parameter.

[0025] Specifically, edge points are sampled in at least three non-collinear directions along the wafer edge. Based on these sampled edge points, a circle is fitted to determine the coordinates of the wafer's geometric center in the stage's mechanical coordinate system, including: S11. Collect multiple edge points in the 0°, 120° and 240° regions of the wafer edge; S12. Based on the multiple edge points, the coordinates of the wafer geometric center in the stage mechanical coordinate system are calculated using the least squares circle fitting algorithm.

[0026] Before the scan begins, the system performs an edge detection operation: at least three directions are selected around the wafer for edge detection, that is, N points are collected in each of the approximately 0°, 120° and 240° regions of the wafer edge (for example, 5-10 points are collected in each region).

[0027] See Figure 5 As shown, based on the coordinates of the three edge points obtained, the true center position of the wafer is calculated using the least squares circle fitting method. It can be understood that when the mechanical center of the stage is used as the origin coordinate, the calculated geometric center of the wafer corresponds to the eccentricity parameter. When the stage is moved based on the eccentricity parameter for compensation, the translational eccentricity error caused by the manual application of the blue film can be effectively eliminated.

[0028] S2. Based on the eccentricity parameter and at least two alignment marks distributed at similar radial distances on the wafer, a hierarchical alignment method is used to determine the relative rotational deviation of the wafer. Specifically, step S2 includes: S21. After the stage is compensated based on the eccentricity parameter, the angle deviation between the actual position and the theoretical position of the first alignment mark is obtained by image recognition based on the first alignment mark in the inner circle region of the wafer, which is used as the coarse rotation deviation of the wafer. S22. After the stage is compensated for the coarse rotation deviation, the actual position of the second alignment mark and the theoretical position of the second alignment mark are obtained by image recognition based on the second alignment mark in the outer ring region of the wafer, which is used as the precise rotation deviation of the wafer.

[0029] It is worth noting that the wafer rotation caused by film application can cause the alignment marks to shift out of view, resulting in alignment failure. Therefore, this embodiment proposes a rotation correction strategy based on radial distance-based hierarchical alignment. This includes primary alignment (coarse alignment): using the Mark points closest to the wafer center (inner wafer region) for initial gripping. See [link to documentation]. Figure 6 As shown, according to the arc length formula L=R×θ, for the same rotation angle deviation θ, the smaller the radius R, the smaller the resulting displacement L. Therefore, even with rotation, the Mark point near the center is likely to remain within the camera's FOV. Secondary alignment (fine alignment): Based on the coarse angle calculated from the primary alignment, the coordinate system is corrected, and then the Mark point far from the center (the outer edge of the wafer) is captured, using a long lever arm to improve the accuracy of the angle calculation. Through this two-stage alignment mechanism, even if the wafer undergoes a large angle rotation, the AOI can still ensure accurate and successful final alignment.

[0030] Understandably, the peripheral Mark has high accuracy and is more reliable than the central Mark for final attitude estimation; combined with primary alignment, it can handle rotation angles of ±25° or even larger; and it avoids the problem of traditional one-time Mark alignment failure, thus significantly improving rotation robustness.

[0031] S3. Determine the target stage position for compensating for and eliminating eccentricity and rotation errors based on the eccentricity parameters and rotation deviation. S4. Control the stage to move to the target stage position to complete wafer alignment.

[0032] The principle behind the above steps is explained below: First, let's explain theoretically. Based on step S1, the coordinates of the wafer's geometric center can be calculated. According to the calculation The original theoretical Wafer coordinates Translate all coordinates to generate the first version of the corrected coordinates. At this point, the eccentricity error has been eliminated, leaving only the rotation error.

[0033] Then, a concentric circle hierarchical search is performed: Primary alignment (anti-rotation): Move the camera to the new coordinates of the first alignment mark. Because R is very small, even if the wafer is rotated by 25 degrees, the point remains within the field of view (FOV); the image is captured and the current approximate rotation angle is calculated. ;use Perform a second coordinate transformation on the Wafer coordinates.

[0034] Secondary alignment (high precision): Move the camera to the second alignment mark (located at the edge of the wafer, most sensitive to angle changes); image recognition, and calculate the precise rotation angle. ;use Perform a third coordinate transformation on Wafer.

[0035] If the point still cannot be found even after using the first alignment mark (indicating a large error in manual film application), the system automatically triggers an Archimedean spiral search centered on the calculated coordinates. The camera then... Centered on the target, the system moves in a spiral motion from the inside out, continuously taking pictures until the Mark point feature is captured. This serves as an anomaly handling mechanism, ensuring the system's robustness.

[0036] It's worth noting that in the actual implementation, the camera is fixed in place; what can be adjusted is the mechanical stage. Three axes, see Figure 7 As shown, the above uses and The principle and specific method for updating the Wafer coordinate system are as follows: Due to film application deviations, the wafer center and the mechanical rotation center do not coincide. This causes the wafer to shift after rotation using the center mark, requiring timely updates to the relationship between the wafer and mechanical coordinate systems for accurate alignment in the next operation. This embodiment uses linked compensation control, upgrading a pure image algorithm to a deep fusion of "image + motion control." The principle is that the system no longer simply controls... Instead of rotating the axis, it calculates how much the wafer would need to rotate around its own geometric center. Rotation (spinning in place), mechanical stage How should the three axes be synchronized? First, calculate the wafer's geometric center through edge fitting. Coordinates in the machine coordinate system When angle correction is needed At that time, calculate new location , To make the camera perceive the wafer as spinning in place, the stage must simultaneously move in the opposite direction to compensate for the displacement. This relationship is used to correct the relationship between the global and local coordinate systems. In the camera's field of view, the wafer appears to be rotating around its own center, and the alignment markers will not be moved out of the field of view due to eccentricity.

[0037] Furthermore, if the blue film has wrinkles, uneven film tension, or if the edge-finding algorithm is interfered with by edge burrs, the calculated center of the circle will be affected. and the true center The deviation was, for example, 0.5mm. When the axis was moved to the calculated position to photograph the Mark point, it was found that because the center of the circle was calculated incorrectly, the Mark point did not appear in the expected position, and even deviated too much and went out of view again. To solve the above problem, the following steps can be performed: Edge fitting: Roughly calculate the eccentricity vector The system knows that this coordinate is likely inaccurate (it may have an error δ), but it is currently the only reference benchmark.

[0038] Inner ring pre-alignment (without rotation, to obtain true angles): only movement Look at the inner circle Mark point and calculate the angle deviation. At this point, the accurate angle error is obtained, but the center coordinates of the circle still have errors.

[0039] Predictive rotation: Calculating rotation Then, the Mark point will move to the predicted coordinates.

[0040] Chase-and-go movement: platform rotation At the same time, the chunk moves directly to this "predicted coordinates" to wait for the Mark point to appear.

[0041] Secondary correction: Take another photo at the "predicted coordinates". If the center of the circle is not calculated accurately, the Mark point, although in the field of view, is not in the exact center of the field of view. Take another photo to identify the current pixel deviation of the Mark point. Then, control the XY axis to make one last tiny movement, align the Mark point, and eliminate any remaining minor errors.

[0042] Figure 8 Sub-figure (a) Prediction stage: Based on the center point O_fit and target rotation angle obtained from step S1, the system calculates the theoretical predicted coordinates of the Mark point. The dashed box in the figure represents the target area where the camera plans to move. Due to the presence of blue film wrinkles or fitting residuals, there is a slight deviation between the actual physical position of the Mark point and the predicted position (indicated by the dashed arrow in the figure).

[0043] Sub-image (b) Catching Phase: The system controls the platform and camera to work together, rapidly moving the camera's field of view to the predicted coordinates. At this point, although the Mark point successfully falls within the camera's FOV, it is not at the center of the field of view. The image processing unit immediately identifies the current frame and calculates the pixel deviation value of the Mark point's center relative to the FOV center. .

[0044] Subgraph (c) Correction Phase: The system corrects the deviation value A secondary fine-tuning command is generated to control the relative movement of the X / Y axes. After the movement is completed, the Mark point is precisely placed at the center of the FOV, eliminating the alignment deviation caused by edge fitting errors and achieving high-precision final alignment.

[0045] Based on the wafer coordinate transformation of the above embodiments, a transformation model including a rotation center offset parameter is proposed in a preferred embodiment. Traditional AOI assumes that the wafer is perfectly aligned. The equipment considers the wafer center to be equal to the stage center; if you want to find the die at coordinates (10, 20), the axis can be directly moved to (10, 20), and if there is a deviation, a simple (dx, dy) correction is added globally. However, since the blue film is applied manually, the wafer geometric center... and platform center They're not even at the same point. All wafer diagrams (the location of the die) are based on the geometric center of the wafer. The origin is the axis of motion; all axial movements (rotation, translation) are centered on the machine center. Based on this, the system needs to acknowledge the separation of these two coordinate systems at the underlying algorithm level. It no longer attempts to force the wafer to be centered, but instead establishes a bridge matrix (…). This describes the eccentricity between the two coordinate systems in real time. The transformation formula in this application introduces a physical eccentricity term:

[0046] in This is a matrix describing the blue film mounting error. This means that the system maintains two coordinate systems: one is the physical coordinate system of the stage, and the other is the floating coordinate system of the wafer, which are linked by real-time calculated eccentric vectors.

[0047] In matrix multiplication, the operations are performed from right to left. The following simulates how a coordinate point (x, y) is gradually "transformed" to its final position: first step: These are the theoretical coordinates on the Wafer diagram, which are relative to the geometric center of the wafer.

[0048] Step Two: The eccentric translation matrix is ​​mathematically expressed as:

[0049] To achieve the aforementioned dynamic coordinate system mapping, this embodiment employs a 3×3 homogeneous transformation matrix for computation. Traditional two-dimensional coordinate transformations cannot simultaneously represent rotation and translation within a single matrix multiplication, leading to cumbersome calculation steps and a tendency to introduce accumulated errors. It shifts the reference frame of the coordinate points from the "wafer geometric center" to the "platform mechanical center," establishing a transformation relationship between the two coordinate systems. The parameters of this matrix... The eccentricity parameters are derived from the edge fitting in step S1.

[0050] Step 3: (Mechanical rotation matrix), its mathematical expression is:

[0051] This describes the actual degree of rotation of the platform. The 2x2 column in the top left corner represents rotation. A 0 in the third column indicates no translation (pure rotation) in this step. It maintains a 3x3 formation, allowing it to work with columns containing translation data. Direct multiplication.

[0052] Step 4: (Final error correction matrix) Even after the preceding precise calculations, there may still be residual errors at the micrometer level (identified by the alignment Mark points) or global coordinate translations. This matrix is ​​used for final fine-tuning.

[0053] See Figure 9As shown, the formula in this embodiment is a chain matrix transformation, the logic of which is first translation (eccentricity) -> then rotation -> then translation (correction). It addresses the error in the film application technique (…). ")" and "axis motion control" The wafer is completely separated from the eccentric edge. This ensures that no matter how off-center the wafer is, as long as the edge fitting calculates T_eccentric, subsequent coordinate transformations are precise mathematical calculations, eliminating the need for blind searches. If thermal expansion or slight slippage of the wafer is detected during inspection, only updates are needed. With this matrix parameter, the coordinates of all dies will be automatically corrected, eliminating the need to remeasure the wafer.

[0054] It is worth noting that the use of a 3×3 homogeneous transformation matrix in this application to construct the model means that the system architecture is based on the standard of robot kinematics, which has high computational efficiency. No matter how many steps are involved (eccentricity, rotation, secondary correction, thermal expansion correction, etc.), the system only needs to multiply these 3×3 matrices together to form a unique 3×3 total matrix, and then perform a single multiplication on the coordinates of thousands of dies.

[0055] Figure 9 Area A (Map space): Represents the area based on the geometric center of the wafer. The original atlas coordinate system was established, in which These are the theoretical coordinates of the grain to be measured. At this point, no physical errors have been considered. Transformation 1 ( The eccentricity matrix is ​​calculated through edge fitting. The wafer is translated along the eccentricity vector direction, so that the origin of the coordinate system shifts from the wafer center. Virtual switch to platform mechanical center This step generates intermediate coordinates containing eccentricity information in intermediate space B. Transformation 2 ( ): Represents the physical rotation matrix of the platform motor. The system is based on the mechanical center. A rotational transformation is performed on the intermediate coordinates to simulate the actual attitude changes of the wafer in physical space. Area C (physical space): After the above chain transformation, the system calculates the final position Target of the target point in the physical stage coordinate system, thereby guiding... The shaft motor is linked to accurately capture targets that undergo nonlinear displacement due to eccentricity and rotation.

[0056] The wafer position compensation alignment method in this application determines the eccentricity parameter of the wafer's geometric center relative to the mechanical center of the stage; based on the eccentricity parameter and at least two alignment marks distributed radially at similar distances on the wafer, a graded alignment method is used to determine the relative rotational deviation of the wafer; according to the eccentricity parameter and the rotational deviation, a target stage position is determined to compensate for and eliminate eccentricity and rotational errors; and the stage is controlled to move to the target stage position to complete the wafer alignment.

[0057] Therefore, by determining the eccentricity parameter of the wafer's geometric center relative to the mechanical center of the stage, the translational eccentricity error caused by wafer placement can be effectively eliminated. Furthermore, based on at least two alignment marks distributed at similar radial distances, a hierarchical alignment method is adopted. The characteristic of the near-center mark, which has small displacement under rotation and is less likely to lose its field of view, is used to improve the initial capture success rate. At the same time, the characteristic of the far-center mark, which is sensitive to angular changes, is used to improve the calculation accuracy of rotational deviation, thus solving the contradiction that a single mark cannot simultaneously ensure alignment success rate and accuracy. Finally, the target stage position is determined and the motion is controlled based on the linkage of the eccentricity parameter and rotational deviation, realizing integrated compensation for eccentricity error and rotational error, which significantly improves the overall success rate, accuracy, and robustness of wafer alignment.

[0058] Secondly, embodiments of this application also provide a wafer position compensation alignment device.

[0059] In one embodiment, reference is made to Figure 10 , Figure 10 This is a functional block diagram of an embodiment of the wafer position compensation alignment device of this application. Figure 10 As shown, the wafer position compensation alignment device includes: The compensation module is used to determine the eccentricity parameter of the wafer's geometric center relative to the mechanical center of the stage. The compensation module also determines the relative rotational deviation of the wafer based on the eccentricity parameter and at least two alignment marks that are radially distributed at similar distances on the wafer, using a graded alignment method. The calculation module determines the target stage position for compensating for and eliminating eccentricity and rotation errors based on the eccentricity parameters and rotation deviations. The control module is used to control the stage to move to the target stage position in order to complete the wafer alignment.

[0060] Further, in one embodiment, the compensation module determines the eccentricity parameter of the wafer's geometric center relative to the stage's mechanical center, including: Edge points are sampled in at least three non-collinear directions at the edge of the wafer. Based on the sampled edge points, a circle is fitted to determine the coordinates of the wafer's geometric center in the mechanical coordinate system of the stage, which are used as the eccentricity parameter.

[0061] Further, in one embodiment, the compensation module samples edge points in at least three non-collinear directions of the wafer edge, performs circle fitting based on the sampled edge points, and determines the coordinates of the wafer's geometric center in the stage mechanical coordinate system, including: Multiple edge points were collected in the 0°, 120° and 240° regions at the wafer edge; Based on multiple edge points, the coordinates of the wafer's geometric center in the stage mechanical coordinate system are calculated using the least squares circle fitting algorithm.

[0062] Further, in one embodiment, the compensation module determines the relative rotational deviation of the wafer based on the eccentricity parameter and at least two alignment marks distributed at approximately the same radial distance on the wafer, using a graded alignment method, including: After the stage is compensated based on the eccentricity parameters, the angle deviation between the actual position and the theoretical position of the first alignment mark in the inner circle region of the wafer is obtained by image recognition based on the first alignment mark, which is used as the coarse rotation deviation of the wafer. After the stage is compensated for the coarse rotational deviation, the actual position of the second alignment mark and the angular deviation of the theoretical position of the second alignment mark are obtained by image recognition based on the second alignment mark in the outer ring region of the wafer, which is used as the precise rotational deviation of the wafer.

[0063] Furthermore, in one embodiment, the compensation module is also used for: If the first alignment mark does not enter the field of view of image recognition, the stage is controlled to move the wafer, with the theoretically calculated position of the first alignment mark as the center, and the wafer moves along a preset spiral trajectory. During the movement, the stage is driven to continuously acquire images until the first alignment mark is captured. The theoretical calculated position of the first alignment mark is the position of the first alignment mark in the wafer coordinate system after compensation based on the eccentricity parameter.

[0064] Furthermore, in one embodiment, the compensation module is also used for: Obtain the positional deviation between the actual imaging position of the alignment marker in the field of view and the center of the field of view; Based on the positional deviation, a fine-tuning command is generated to control the stage to move until the alignment mark is located in the center of the field of view.

[0065] Furthermore, in one embodiment, the control module is used to: Based on homogeneous transformation matrix Characterizing positional deviation based on homogeneous transformation matrix Characterizing rotational deviation based on homogeneous transformation matrix Characterizing eccentricity parameters; According to the formula: Calculate the position of the target platform ,in, These are the theoretical coordinates on the wafer relative to the wafer's geometric center.

[0066] The functions of each module in the wafer position compensation alignment device correspond to the steps in the wafer position compensation alignment method embodiment, and their functions and implementation processes will not be described in detail here.

[0067] Thirdly, embodiments of this application provide a wafer position compensation alignment device, which can be a device with data processing capabilities such as a personal computer (PC), a laptop computer, or a server.

[0068] Reference Figure 11 , Figure 11 This is a schematic diagram of the hardware structure of the wafer position compensation and alignment device involved in the embodiments of this application. In the embodiments of this application, the wafer position compensation and alignment device may include a processor, a memory, a communication interface, and a communication bus.

[0069] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0070] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces used for interconnecting devices within the wafer position compensation alignment device, as well as interfaces used for interconnecting the wafer position compensation alignment device with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0071] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0072] The processor can be a general-purpose processor, which can call the wafer position compensation alignment program stored in memory and execute the wafer position compensation alignment method provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the wafer position compensation alignment program is called can be referred to in the various embodiments of the wafer position compensation alignment method of this application, and will not be repeated here.

[0073] Those skilled in the art will understand that Figure 11 The hardware structure shown does not constitute a limitation of this application and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0074] Fourthly, embodiments of this application also provide a computer-readable storage medium.

[0075] The present application has a computer-readable storage medium storing a wafer position compensation alignment program, wherein when the wafer position compensation alignment program is executed by a processor, it implements the steps of the wafer position compensation alignment method as described above.

[0076] The method implemented when the wafer position compensation alignment procedure is executed can be referred to in various embodiments of the wafer position compensation alignment method of this application, and will not be repeated here.

[0077] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0078] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0079] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0080] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0081] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0082] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0083] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A wafer position compensation alignment method, characterized in that, The wafer position compensation alignment method includes: Determine the eccentricity parameters of the wafer's geometric center relative to the mechanical center of the stage; Based on the aforementioned eccentricity parameters and at least two alignment marks distributed at similar radial distances on the wafer, a hierarchical alignment method is used to determine the relative rotational deviation of the wafer. Based on the eccentricity parameters and rotational deviation, determine the target stage position for compensating for and eliminating eccentricity and rotational errors; Control the stage to move to the target stage position to complete wafer alignment.

2. The wafer position compensation alignment method as described in claim 1, characterized in that, The eccentricity parameter used to determine the position of the wafer's geometric center relative to the mechanical center of the stage includes: Edge points are sampled in at least three non-collinear directions at the edge of the wafer. Based on the sampled edge points, a circle is fitted to determine the coordinates of the wafer's geometric center in the mechanical coordinate system of the stage, which are used as the eccentricity parameter.

3. The wafer position compensation alignment method as described in claim 2, characterized in that, The step of sampling edge points in at least three non-collinear directions of the wafer edge, performing circle fitting based on the sampled edge points, and determining the coordinates of the wafer's geometric center in the stage mechanical coordinate system includes: Multiple edge points were collected in the 0°, 120° and 240° regions at the wafer edge; Based on multiple edge points, the coordinates of the wafer's geometric center in the stage mechanical coordinate system are calculated using the least squares circle fitting algorithm.

4. The wafer position compensation alignment method as described in claim 1, characterized in that, Based on the eccentricity parameter and at least two alignment marks distributed at varying radial distances on the wafer, a hierarchical alignment method is used to determine the relative rotational deviation of the wafer, including: After the stage is compensated based on the eccentricity parameters, the angle deviation between the actual position and the theoretical position of the first alignment mark in the inner circle region of the wafer is obtained by image recognition based on the first alignment mark, which is used as the coarse rotation deviation of the wafer. After the stage is compensated for the coarse rotational deviation, the actual position of the second alignment mark and the angular deviation of the theoretical position of the second alignment mark are obtained by image recognition based on the second alignment mark in the outer ring region of the wafer, which is used as the precise rotational deviation of the wafer.

5. The wafer position compensation alignment method as described in claim 4, characterized in that, Also includes: If the first alignment mark does not enter the field of view of image recognition, the stage is controlled to move the wafer, with the theoretically calculated position of the first alignment mark as the center, and moves according to a preset spiral trajectory. During the movement, images are continuously acquired until the first alignment mark is captured. The theoretical calculated position of the first alignment mark is the position of the first alignment mark in the wafer coordinate system after compensation based on the eccentricity parameter.

6. The wafer position compensation alignment method as described in claim 1, characterized in that, Also includes: Obtain the positional deviation between the actual imaging position of the alignment marker in the field of view and the center of the field of view; Based on the positional deviation, a fine-tuning command is generated to control the stage to move until the alignment mark is located in the center of the field of view.

7. The wafer position compensation alignment method as described in claim 6, characterized in that: Based on homogeneous transformation matrix Characterizing positional deviation based on homogeneous transformation matrix Characterizing rotational deviation based on homogeneous transformation matrix Characterizing eccentricity parameters; According to the formula: Calculate the position of the target platform ,in, These are the theoretical coordinates on the wafer relative to the wafer's geometric center.

8. A wafer position compensation alignment device, characterized in that, The wafer position compensation and alignment device includes: The compensation module is used to determine the eccentricity parameter of the wafer's geometric center relative to the mechanical center of the stage. The compensation module also determines the relative rotational deviation of the wafer based on the eccentricity parameter and at least two alignment marks that are radially distributed at similar distances on the wafer, using a graded alignment method. The calculation module determines the target stage position for compensating for and eliminating eccentricity and rotation errors based on the eccentricity parameters and rotation deviations. The control module is used to control the stage to move to the target stage position in order to complete the wafer alignment.

9. A wafer position compensation and alignment device, characterized in that, The wafer position compensation alignment device includes a processor, a memory, and a wafer position compensation alignment program stored in the memory and executable by the processor, wherein when the wafer position compensation alignment program is executed by the processor, it implements the steps of the wafer position compensation alignment 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 a wafer position compensation alignment program, wherein when the wafer position compensation alignment program is executed by a processor, it implements the steps of the wafer position compensation alignment method as described in any one of claims 1 to 7.

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