Wafer image scanning method and device, terminal equipment and readable storage medium

Abstract

The embodiment of the invention discloses a wafer image scanning method and device, terminal equipment and a readable storage medium, and the method comprises the steps: detecting the wafer defocus height of a to-be-scanned wafer carried on a motion platform, so as to obtain the reference height for the focus tracking of the to-be-scanned wafer; generating a first motion track based on the position information of each feature point included in the wafer focusing calibration data, and controlling the motion table to move so as to control the to-be-scanned wafer to move based on the first motion track; acquiring focus tracking compensation heights of the to-be-scanned wafer moving to each scanning point based on the wafer focusing calibration data; and obtaining a defocus feedback parameter when the to-be-scanned wafer moves to each scanning point, generating a real-time focusing height when the to-be-scanned wafer moves to each scanning point based on the reference height, the focus tracking compensation height and the defocus feedback parameter, and focusing the to-be-scanned wafer based on the real-time focusing height to obtain a wafer image of the to-be-scanned wafer, and the focusing response speed is high, the focusing precision is high, and the applicability is high.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a wafer image scanning method, apparatus, terminal device and readable storage medium. Background Art

[0002] Semiconductor inspection technology plays an important role in the semiconductor design, production, packaging and testing processes, and is the key to improving the yield rate of semiconductor production. When inspecting wafer semiconductors, ultra-high-resolution linear array cameras are often used to scan the wafer to obtain wafer images, and then perform defect detection based on the wafer images. With the rapid development of semiconductor technology, the process reduction of semiconductor chips, and the improvement of the accuracy and resolution of semiconductor defect detection, more accurate and fast focusing is required when collecting wafer images to avoid problems such as defocus, blur or blurring of the collected wafer images, which leads to low wafer detection accuracy. Therefore, how to focus at high speed and prevent defocus is crucial for semiconductor defect detection.

[0003] In the prior art, during the wafer scanning process, focusing is to detect the defocus amount of the scanning feature point in real time when the moving stage moves to the scanning feature point, and then control the movement of the moving stage based on the real-time detected defocus amount to achieve real-time focusing. However, in the prior art, in the process of controlling the movement of the moving stage based on the real-time detected defocus amount, the link from defocus amount detection to focusing is long and the delay is large, resulting in slow focus response and poor performance. In addition, when the fluctuation distance of the wafer surface exceeds the tracking focus distance, it is impossible to focus accurately, the focus accuracy is low, and the applicability is poor. Summary of the invention

[0004] The present application provides a wafer image scanning method, device, terminal equipment and readable storage medium, which can improve the focus response speed and focus accuracy and have strong applicability.

[0005] In a first aspect, an embodiment of the present application provides a wafer image scanning method, comprising: detecting a wafer defocus height of a wafer to be scanned carried on a moving table to obtain a reference height for tracking focusing on the wafer to be scanned; generating a first motion trajectory based on position information of each feature point included in wafer focus calibration data, and controlling the moving table to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory; obtaining a tracking focus compensation height when the wafer to be scanned moves to each scanning point based on the wafer focus calibration data, wherein the scanning point includes the feature point and non-feature points other than the feature point; obtaining a defocus feedback parameter when the wafer to be scanned moves to each scanning point, generating a real-time focus height when the wafer to be scanned moves to each scanning point based on the reference height, the focus compensation height and the defocus feedback parameter, and focusing the wafer to be scanned based on the real-time focus height to obtain a wafer image of the wafer to be scanned. By adopting the present application, the defocus height of the wafer can be compensated in advance before scanning the wafer to be scanned based on the reference height and the focus compensation height of each scanning point, and the real-time focus height of the wafer to be scanned when it moves to each scanning point can be adjusted in real time through the defocus feedback parameters obtained in real time. Therefore, the focus response speed can be improved, the focus accuracy can be improved, and the applicability is strong.

[0006] In a possible implementation of the first aspect, the above-mentioned acquisition of the focus compensation height of the wafer to be scanned moving to each scanning point based on the wafer focus calibration data includes: acquiring the focus compensation height of the wafer to be scanned moving to each feature point from the wafer focus calibration data, and acquiring the focus compensation height of the wafer to be scanned moving to the non-feature point based on the focus compensation height of each feature point, so as to obtain the focus compensation height of the wafer to be scanned moving to each scanning point. By adopting the present application, the focus compensation height of the non-feature point can be obtained through the focus compensation height of the feature point, which can be applied to the situation where the focus compensation height cannot be directly obtained from the wafer focus calibration data based on the position information of the non-feature point, thereby improving the applicability.

[0007] In a possible implementation of the first aspect, the above-mentioned focusing compensation height based on the above-mentioned each feature point to obtain the focusing compensation height of the above-mentioned wafer to be scanned moving to the above-mentioned non-feature point includes: when the above-mentioned wafer to be scanned moves to any non-feature point other than the above-mentioned each feature point, determining the target feature point closest to any of the above-mentioned non-feature points from the above-mentioned each feature point; obtaining the target focusing compensation height and target position information of the above-mentioned target feature point from the above-mentioned wafer focus calibration data, and obtaining the focusing compensation height of any of the above-mentioned non-feature points based on the interpolation relationship between the above-mentioned target focusing compensation height and the above-mentioned target position information, so as to obtain the focusing compensation height of each of the above-mentioned non-feature points. By adopting the present application, the focusing compensation height of the non-feature point is calculated by the interpolation relationship between the target focusing compensation height and the target position information of the target feature point closest to the non-feature point. The appropriate interpolation calculation method can be selected according to the product requirements and the interpolation relationship, and the focusing accuracy is higher and the applicability is stronger.

[0008] In a possible implementation of the first aspect, the real-time focus height generated when the wafer to be scanned moves to each of the above-mentioned scanning points based on the reference height, the focus compensation height and the defocus feedback parameter includes: calculating the superimposed height of the reference height, the focus compensation height and the defocus feedback parameter of any scanning point, and determining the superimposed height as the real-time focus height when the wafer to be scanned moves to any of the above-mentioned scanning points, so as to generate the real-time focus height when the wafer to be scanned moves to each of the above-mentioned scanning points. By adopting the present application, the error in the focusing process can be fed back in real time by detecting the defocus feedback parameter, and the height of the moving stage can be adjusted in real time based on the real-time focus height to eliminate the error in the focusing process, thereby further improving the focusing accuracy and applicability.

[0009] In a possible implementation of the first aspect, before the above-mentioned detection of the wafer defocus height of the wafer to be scanned carried on the moving stage, the above-mentioned method also includes: controlling the moving stage to move based on the second motion trajectory to control the reference wafer carried on the above-mentioned moving stage to move based on the above-mentioned second motion trajectory, obtaining the wafer defocus height and position information of the reference wafer moving to each feature point in the above-mentioned second motion trajectory, and determining the focus compensation height of each feature point in the above-mentioned second motion trajectory based on the wafer defocus height of each feature point; generating wafer focus calibration data based on the above-mentioned position information and the above-mentioned focus compensation height of each feature point; wherein the above-mentioned second motion trajectory includes one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygonal trajectory and a horizontal and vertical trajectory. By adopting the present application, the reference wafer can be scanned before scanning the wafer to be scanned, and then the wafer focus calibration data can be obtained to predict the focus compensation height of each scanning point during the scanning process of the wafer to be scanned, so that compensation can be made in advance through prediction, which can further shorten the focus time of the wafer to be scanned and improve the focus response speed.

[0010] In a possible implementation of the first aspect, the wafer focus calibration data is generated based on the position information of the above-mentioned each feature point and the above-mentioned focus compensation height, including: generating a spatial two-dimensional focus compensation height table based on the above-mentioned position information of the above-mentioned each feature point and the above-mentioned focus compensation height, and using the above-mentioned focus compensation height table as the wafer focus calibration data, wherein one dimension in the above-mentioned spatial two-dimensional focus compensation height table is used to store the above-mentioned position information of the above-mentioned each feature point, and another dimension in the above-mentioned spatial two-dimensional focus compensation height table is used to record the above-mentioned focus compensation height of the above-mentioned each feature point. By adopting the present application, a spatial two-dimensional focus compensation height table can be generated to quickly obtain the focus compensation height corresponding to the position information according to the position information, thereby further improving the focus response speed, and the applicability is strong.

[0011] In a possible implementation of the first aspect, the wafer focus calibration data is generated based on the position information of the above-mentioned each feature point and the above-mentioned focus compensation height, including: generating a spatial two-dimensional focus compensation curve based on the above-mentioned position information of the above-mentioned each feature point and the above-mentioned focus compensation height, and using the above-mentioned focus compensation curve as the wafer focus calibration data, wherein one dimension of the above-mentioned spatial two-dimensional focus compensation curve is used to store the above-mentioned position information of the above-mentioned each feature point, and another dimension of the above-mentioned spatial two-dimensional focus compensation curve is used to record the above-mentioned focus compensation height of the above-mentioned each feature point. By adopting the present application, a spatial two-dimensional focus compensation curve can be generated to be applicable to the situation where a large amount of data such as position information leads to a complicated spatial two-dimensional focus compensation table and a slow query speed, thereby further improving the focus response speed and improving applicability.

[0012] In a possible implementation of the first aspect, the above-mentioned acquisition of the focus compensation height when the wafer to be scanned moves to each of the above-mentioned feature points from the above-mentioned wafer focus calibration data includes: when the wafer to be scanned moves to any of the above-mentioned feature points, the position information of any of the above-mentioned feature points is acquired, and the focus compensation height of any of the above-mentioned feature points is calculated based on the position information of any of the above-mentioned feature points and the above-mentioned spatial two-dimensional focus compensation curve, so as to obtain the focus compensation height of each of the above-mentioned feature points. By adopting the present application, a spatial two-dimensional focus compensation curve can be generated to quickly calculate the focus compensation height corresponding to the position information according to the position information, thereby further improving the focus response speed, and having strong applicability.

[0013] In a second aspect, an embodiment of the present application provides a wafer image scanning device, which includes a module or unit for executing a wafer image scanning method provided in the first aspect or any possible implementation manner of the first aspect.

[0014] Exemplarily, the device comprises:

[0015] A detection module, used for detecting a wafer defocus height of a wafer to be scanned carried on a moving stage, so as to obtain a reference height for tracking focus of the wafer to be scanned;

[0016] A generating module, configured to generate a first motion trajectory based on the position information of each feature point included in the wafer focus calibration data, and control the motion stage to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory;

[0017] An acquisition module, used for acquiring the focus compensation height of the wafer to be scanned when it moves to each scanning point based on the wafer focus calibration data, wherein the scanning point includes the feature point and non-feature points other than the feature point;

[0018] A focusing module is used to obtain the defocus feedback parameters when the wafer to be scanned moves to the above-mentioned scanning points, generate the real-time focusing height when the wafer to be scanned moves to the above-mentioned scanning points based on the above-mentioned reference height, the above-mentioned focus compensation height and the above-mentioned defocus feedback parameters, and focus the wafer to be scanned based on the above-mentioned real-time focusing height to obtain the wafer image of the wafer to be scanned.

[0019] In a third aspect, an embodiment of the present application provides a terminal device, comprising: a processor and a memory; the processor is connected to the memory, wherein the memory is used to store program code, and the processor is used to call the program code to execute the wafer image scanning method provided in the first aspect or any possible implementation method of the first aspect.

[0020] In a fourth aspect, an embodiment of the present application provides a wafer image scanning system, comprising: a moving stage such as the terminal device provided in the third aspect; wherein the moving stage is used to carry a wafer.

[0021] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. The computer program is suitable for being loaded by a processor and executing the wafer image scanning method provided by the first aspect or any possible implementation method of the first aspect.

[0022] In a sixth aspect, an embodiment of the present application provides a computer program product, wherein the computer program product comprises computer instructions, and the computer instructions are suitable for being loaded by a processor and executing the wafer image scanning method provided by the first aspect or any possible implementation scheme of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the architecture of a wafer image scanning system provided in an embodiment of the present application;

[0024] Figure 2is a schematic diagram of a spiral trajectory provided in an embodiment of the present application;

[0025] Figure 3 It is a schematic diagram of concentric circle trajectories provided in an embodiment of the present application;

[0026] Figure 4 is a schematic diagram of a polygonal trajectory provided by an embodiment of the present application;

[0027] Figure 5 It is a schematic diagram of horizontal and vertical trajectories provided in an embodiment of the present application;

[0028] Figure 6 It is a schematic diagram of a block trajectory provided in an embodiment of the present application;

[0029] Figure 7 It is a schematic diagram of a process of a wafer image scanning method provided by an embodiment of the present application;

[0030] Figure 8 is another flow chart of the wafer image scanning method provided by an embodiment of the present application;

[0031] Fig. 9 This is a schematic diagram of the spatial two-dimensional focus tracking compensation height provided by the embodiment of the present application;

[0032] Fig.10 is a schematic diagram of a flow chart of generating a real-time focus height provided in an embodiment of the present application;

[0033] Fig.11 is a schematic structural diagram of a wafer image scanning device provided in an embodiment of the present application;

[0034] Fig.12 It is a schematic diagram of the structure of the terminal device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0036] To facilitate understanding, some nouns are briefly explained as follows:

[0037] 1. Feature points, also known as ideal feature points or target feature points, can be marking patterns used for alignment, or the upper left corner of a die, and need to have unique features that are easily identifiable. They can be selected from feature points used for wafer alignment, or they can be obtained by performing artificial intelligence annotation in a wafer map. In an embodiment of the present application, a plurality of feature points are included in the first motion trajectory of the wafer to be scanned and the second motion trajectory of the reference wafer.

[0038] 2. Reference height: the initial height caused by the thickness of the wafer or the thickness of the motion stage. The wafer can be preliminarily focused based on the reference height.

[0039] 3. Wafer defocus height, also known as defocus amount, refers to the data indicating the focus offset difference when acquiring the wafer image during the wafer scanning process. It can be used to adjust the distance between the wafer to be inspected and the image acquisition device so that the image reaches the preset clarity. The preset clarity refers to the specified value of the wafer image clarity, which can be determined according to the specific form of the product.

[0040] 3. The focus compensation height is the data used to compensate for the wafer defocus height, that is, the compensation value for focus tracking. By adjusting the height of the motion stage by the focus compensation height, the wafer to be scanned can be adjusted to a focus state where the acquired image reaches a preset clarity.

[0041] 4. Proportional-Integral-Derivative Controller, also known as PID controller. PID controller includes three parts: proportional, integral and differential. It can achieve real-time adjustment of the image by amplifying, integrating and differentiating the feedback parameters.

[0042] 5. Defocus feedback parameter refers to the feedback parameter of the wafer defocus height during the movement of the moving stage, which is also called feedback PID value. In this application, the defocus feedback parameter can be obtained by obtaining the wafer defocus height of the previous feature point, and the defocus feedback parameter of the first feature point can be empty. The above feedback PID value can be used to implement feedback PID control through the PID controller, which can be used to correct deviations and compensate for the wafer defocus height of the moving stage in real time, which can ensure the stability and accuracy of the system.

[0043] Embodiment 1

[0044] For ease of understanding, this application first describes the architecture of the wafer image scanning system. The wafer image scanning method can be used in the wafer image scanning system. The wafer image scanning system can be applied to wafer scanning scenarios, wafer processing scenarios, etc. Figure 1 , Figure 1 Schematic diagram of the structure of the wafer image scanning system provided by the embodiment of the present application. Figure 1 As shown, the wafer image scanning system may include a moving stage 1a and a terminal device 1b. The terminal device 1b may be used to interact with the moving stage 1a, and may be a tablet, a computer, or the like, for storing and calling program codes to execute the wafer image scanning method. The following describes the interaction process between the terminal device 1b and the moving stage 1a.

[0045] In some feasible embodiments, before scanning the wafer to be scanned, the motion stage 1a may carry a reference wafer for obtaining wafer focus calibration data, and the reference wafer may be a wafer with small or no surface fluctuation error, such as an ultra-flat wafer. The terminal device 1b may control the motion stage 1a to carry the reference wafer to move based on a second motion trajectory to scan the reference wafer. Here, the second motion trajectory may be a motion trajectory pre-planned and set to obtain wafer focus calibration data, including but not limited to a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygonal trajectory, and a horizontal and vertical trajectory. The terminal device 1b may obtain the wafer defocus height and position information of each feature point in the second motion trajectory when the reference wafer moves, and determine the focus compensation height of each feature point based on the wafer defocus height of each feature point. The terminal device may generate wafer calibration data based on the position information and focus compensation height of each feature point.

[0046] Optionally, in some feasible implementations, the wafer calibration data may be stored as a spatial two-dimensional focus compensation height table, in which one dimension stores the position information of each feature point in space, and another dimension stores the focus compensation height of each feature point. Therefore, if the position information of any feature point in space is determined, the focus compensation height corresponding to the position information may be obtained based on the spatial two-dimensional focus compensation height table. In other words, the spatial two-dimensional focus compensation height table stores the position information of each feature point and the focus compensation height corresponding to each position information.

[0047] Optionally, in some feasible implementations, the above-mentioned wafer calibration data can also be stored as a spatial two-dimensional focus compensation curve, in which one dimension is used to store the position information of each feature point, and the other dimension is used to record the focus compensation height of each feature point. For example, the position information of each feature point can be used as the independent variable of the spatial two-dimensional focus compensation curve, and the focus compensation height of each feature point can be used as the dependent variable of the spatial two-dimensional focus compensation curve. The terminal device 1b can use the position information of any feature point as the independent variable of the spatial two-dimensional focus compensation curve, and calculate the focus compensation height corresponding to the position information according to the calculation formula of the spatial two-dimensional focus compensation curve.

[0048] In some feasible implementations, after the terminal device 1b obtains the wafer calibration data, it can scan the wafer 1c to be scanned. The terminal device 1b can detect the wafer defocus height of the wafer 1c to be scanned carried by the moving stage 1a to obtain the reference height of the wafer 1c to be scanned. The terminal device 1b can also generate a first motion trajectory based on the position information of each feature point included in the above-mentioned wafer focus calibration data, and then control the moving stage 1a to carry the wafer 1c to be scanned to move based on the first motion trajectory. It can be understood that the wafer focus calibration data includes the position information of multiple feature points, and the position information of these feature points is obtained by the terminal device 1b scanning the reference wafer during the movement of the reference wafer based on the second motion trajectory. These feature points are feature points on the second motion trajectory. Therefore, the first motion trajectory generated based on the position information of each feature point included in the above-mentioned wafer focus calibration data can be equivalent to the second motion trajectory. Here, the first motion trajectory may be equivalent to the second motion trajectory, including but not limited to the first motion trajectory being exactly the same as the second motion trajectory, or the position deviation between the feature points on the first motion trajectory and the second motion trajectory being within the error range, which may be determined specifically according to the actual application scenario and is not limited here. When the motion stage 1a moves to each feature point in the first motion trajectory, the terminal device 1b may obtain the focus compensation height of each feature point based on the position information of each feature point to perform focus compensation on the wafer 1c to be scanned. For example, if the motion stage 1a moves to any feature point among the feature points and the above-mentioned wafer focus calibration data is a spatial two-dimensional focus compensation height table, the terminal device 1b may query the above-mentioned spatial two-dimensional focus compensation height table according to the position information of any of the above-mentioned feature points to obtain the focus compensation height corresponding to the position information, and use the focus compensation height as the focus compensation height of the wafer 1c to be scanned moving to the feature point. If the motion stage 1a moves to any feature point among the feature points and the wafer focus calibration data is a spatial two-dimensional focus compensation curve, the terminal device 1b can calculate based on the position information of any feature point and the spatial two-dimensional focus compensation curve to obtain the focus compensation height corresponding to the position information, and use the focus compensation height as the focus compensation height of the wafer 1c to be scanned when it moves to the feature point. If the motion stage 1a moves to any non-feature point among the feature points, the terminal device 1b can calculate the focus compensation height of any non-feature point according to the focus compensation height of the feature point closest to the non-feature point.

[0049] In some feasible implementations, the terminal device 1b can also detect the defocus feedback parameters of the wafer 1c to be scanned when it moves to each feature point in real time during the movement of the moving stage 1a, and superimpose the reference height, focus compensation height and defocus feedback parameters of the wafer 1c to be scanned to generate a real-time focus height. The terminal device 1b can focus on the wafer 1c to be scanned based on the real-time focus height to obtain a wafer image of the wafer 1c to be scanned.

[0050] Optionally, in some feasible implementations, the terminal device 1b may include a focus collection system and a controller. The focus collection system may include an image acquisition device, which is used to scan the wafer 1c to be scanned carried by the moving stage 1a to obtain a wafer image of the wafer 1c to be scanned. Optionally, the focus collection system may also include a processor ( Figure 1 (not shown), for example, including a host computer and other devices that can be used to receive and process wafer images, and the above-mentioned processor is used to receive the above-mentioned wafer image and process the wafer image to obtain the position information of each feature point of the wafer 1c to be scanned, defocus feedback parameters, reference height, real-time focus height and other focus data. Among them, the above-mentioned image acquisition device may include a camera and a light source. The above-mentioned camera can be a linear array camera or other device that can acquire wafer images. This application does not limit this, and the linear array camera is used as an example for explanation. The above-mentioned light source can be a laser or other device that can be used to provide lighting when the camera acquires the wafer image. This application does not limit this, and the laser is used as an example for explanation. The camera can scan the wafer 1c to be scanned when the light source provides lighting, and then obtain the wafer image of the wafer 1c to be scanned. Among them, the microprocessor can process the wafer image, and then obtain the reference height of the wafer 1c to be scanned, the position information of each feature point in the wafer 1c to be scanned, and other focus data.

[0051] Optionally, the controller in the terminal device 1b may include a motion controller, a focus controller, a PID controller or other types of controllers, or may include a controller that integrates the functions implemented by controllers such as a motion controller, a focus controller and a PID controller, and this application does not limit this. Optionally, the controller may be configured to execute the control of the image processing unit 100 through the processor ( Figure 1 The processor (not shown) processes the data and generates control instructions based on the data processed by the processor. Optionally, the processor is also integrated into a functional module, such as a central processing functional module in a motion controller, a central processing functional module in a focus controller, or a central processing functional module in a focus collection system, to implement the functions implemented by the processor, which can be determined according to the specific form of the product and is not limited here.

[0052] The focus controller is used to receive the focus data obtained by the focus collection system, so as to obtain the focus compensation height of the wafer 1c to be scanned based on the focus data. The motion controller can receive the focus compensation height sent by the focus controller, and generate a motion control instruction based on the focus compensation height to control the movement of the motion stage 1a, thereby focusing on the wafer. It is understandable that the focus controller can receive the focus data of the focus collection system in real time and obtain the focus compensation height in real time, and then can control the motion stage 1a to focus on the wafer in real time through the motion controller.

[0053] The above-mentioned motion table 1a can be an X / Z / Theta axis motion table, or it can be other motion tables that can carry wafers. This application does not limit this, and takes the X / Z / Theta axis motion table as an example for explanation. It can be understood that the above-mentioned motion table 1a can move on the X-axis, Z-axis and Theta axis, corresponding to lateral movement, vertical movement and rotation angle movement respectively. The above-mentioned motion table 1a can be used to carry wafers and adjust the position of the wafers by movement. Optionally, the above-mentioned motion table 1a can also include a Y-axis motion table, which can carry wafers to move the wafers longitudinally. The above-mentioned motion table 1a can move according to the motion trajectory determined by the terminal device 1b, and the above-mentioned motion trajectory can be one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygonal trajectory and a horizontal and vertical trajectory.

[0054] See also Figure 2 , Figure 2 Schematic diagram of the spiral trajectory provided by the embodiment of the present application. Figure 2 As shown, the spiral trajectory may be an Archimedean spiral, and the spiral trajectory may include multiple feature points, and the motion radius corresponding to the multiple feature points arranged from the outside to the inside decreases. The motion radius is the distance between the scanning feature point and the center of the circle, and the motion radius corresponding to the feature point located on the outside is greater than the motion radius corresponding to the feature point located on the inside.

[0055] See also Figure 3 , Figure 3 Schematic diagram of concentric circle trajectories provided in the embodiment of the present application. Figure 3 As shown, the concentric circle trajectory can be a plurality of circle trajectories with the same center ( Figure 3 Only part of the circle track is shown in the figure), each feature point in the same circle track ( Figure 3 The motion radius corresponding to the feature points (only some feature points are shown in the figure) is the same, and the motion radius corresponding to each feature point included in the circle trajectory from the outside to the inside decreases circle by circle.

[0056] See also Figure 4 , Figure 4 Schematic diagram of polygonal trajectory provided by the embodiment of the present application. Figure 4 As shown, the polygonal trajectory can be composed of multiple concentric geometric trajectories of circumscribed circles ( Figure 4 Only some of the geometric trajectories are shown in the figure), for example, multiple pentagonal trajectories. Multiple vertices in each geometric trajectory are located on the same circle, and the motion trajectory between two adjacent vertices is a straight line. Among them, the feature points ( Figure 4 That is, the movement radius corresponding to the feature points included in the outer geometric trajectory is greater than the movement radius corresponding to the feature points included in the inner geometric trajectory.

[0057] See also Figure 5 , Figure 5 Schematic diagram of the horizontal and vertical tracks provided in the embodiment of the present application. Figure 5 As shown, the horizontal and vertical track (i.e., the Z-shaped track) includes multiple lines of motion tracks ( Figure 5 Only part of the horizontal and vertical tracks are shown in the figure. After scanning each line of motion track, the feature points ( Figure 5 If only some feature points are displayed in the image, the next row of motion trajectories is switched to scan. Each row of motion trajectories includes multiple feature points. Optionally, the horizontal and vertical trajectories may also include multiple columns of motion trajectories, that is, longitudinal motion trajectories, which is not limited in the present application.

[0058] See also Figure 6 , Figure 6 Schematic diagram of the block trajectory provided by the embodiment of the present application. Figure 6 As shown, the block trajectory includes multiple quadrilaterals ( Figure 6 Only part of the block track is shown in the figure), each quadrilateral includes multiple feature points ( Figure 6 Only some feature points are shown in the figure). The motion platform 1a can switch the motion direction when it moves to the vertex of the quadrilateral, and the angle between the direction after switching and the motion direction before switching is 90°.

[0059] To facilitate understanding, the following describes the interaction process between the terminal device 1b and the motion platform 1a by taking the terminal device 1b including a motion controller, a focus controller, and an image acquisition device as an example, wherein the image acquisition device includes a light source and a camera, and a PID control module is integrated in the focus controller. The above-mentioned PID control module is used to execute the functions implemented by the PID controller.

[0060] In some feasible implementations, the terminal device 1b can scan the wafer 1c to be scanned carried on the moving table 1a through the image acquisition device in the focus collection system, obtain the wafer image of the wafer 1c to be scanned, and then obtain the wafer defocus height of the wafer 1c to be scanned based on the wafer image. The terminal device 1b can obtain the reference height for tracking the focus of the wafer 1c to be scanned based on the wafer defocus height through the focus controller. The above-mentioned reference height is the initial height generated by the wafer thickness of the wafer 1c to be scanned, which can be obtained by the height of a feature point in the wafer 1c to be scanned, or by the average height of multiple feature points in the wafer 1c to be scanned, or can be identified from the wafer image through an artificial intelligence algorithm model.

[0061] In some feasible implementations, the terminal device 1b can generate a first motion trajectory based on the position information of each feature point in the wafer focus calibration data through a motion controller, and then generate a motion control instruction based on the first motion trajectory to control the motion stage 1a to move according to the first motion trajectory. It can be understood that the wafer 1c to be scanned carried on the motion stage 1a is relatively stationary with the motion stage 1a, and can follow the motion stage 1a to move according to the first motion trajectory. When the motion stage 1a moves to any feature point, the terminal device 1b can obtain the position information of any of the above feature points through the focus controller, and obtain the focus compensation height corresponding to the position information based on the position information.

[0062] In some feasible implementations, the terminal device 1b can obtain the wafer image of the wafer 1c to be scanned when it moves to each feature point through the image acquisition device, so that the focus controller can obtain the defocus feedback parameters of each feature point based on the wafer image of each feature point. The terminal device 1b can generate the real-time focus height of the wafer 1c to be scanned when it moves to the above-mentioned each feature point based on the reference height, tracking focus compensation height and defocus feedback parameter of the wafer 1c to be scanned through the focus controller, and then focus on the wafer 1c to be scanned based on the real-time focus height. Among them, the defocus feedback parameter is used to indicate the difference between the focus height of the wafer 1c to be scanned and the ideal focus height, that is, the wafer defocus height of the wafer 1c to be scanned; the above-mentioned ideal focus height is used to indicate the focus height of the wafer 1c to be scanned to obtain the wafer image. The above-mentioned real-time focus height can be obtained through the PID control module of the focus controller in the terminal device 1b. Specifically, the terminal device 1b can adjust the above-mentioned tracking focus compensation height based on the feedback parameter and the reference height through the PID control module, and then generate the real-time focus height. The terminal device 1b can control the height of the motion stage 1a based on the above-mentioned real-time focusing height through a motion controller, and thus can focus on the wafer 1c to be scanned to obtain a wafer image of the wafer 1c to be scanned.

[0063] In some feasible implementations, the terminal device 1b may obtain the focus compensation height of each feature point based on the position information of each feature point among the multiple feature points, and obtain the focus compensation height of each non-feature point other than each feature point based on the focus compensation height of each feature point. The non-feature point is a scanning point that is different from the position information of the feature point planned in the first motion trajectory and is generated by the motion trajectory offset caused by factors such as motion error during the actual motion of the motion platform.

[0064] In some feasible implementations, the terminal device 1b can calculate the superimposed height of the baseline height, focus compensation height and defocus feedback parameter of any feature point through the PID control module, and then use the above-mentioned superimposed height as the real-time focus height when the wafer 1c to be scanned moves to any feature point, and then generate the real-time focus height when the wafer 1c to be scanned moves to the above-mentioned each feature point.

[0065] In some feasible implementations, the terminal device 1b can obtain wafer focus calibration data. Specifically, the motion stage 1a can carry a reference wafer, and the terminal device 1b controls the motion stage 1a to move based on the second motion trajectory through a motion controller to control the reference wafer to move based on the second motion trajectory. The terminal device 1b can obtain the wafer image when the reference wafer moves to each feature point in the second motion trajectory through an image acquisition device, and then obtain the wafer defocus height and position information of the reference wafer moving to each feature point through a focus controller, and determine the focus compensation height of each feature point position in the second motion trajectory based on each wafer defocus height. The terminal device 1b can generate wafer focus calibration data based on the position information and focus compensation height of each feature point. Among them, the second motion trajectory may include one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygonal trajectory, and a horizontal and vertical trajectory, and the second motion trajectory has a corresponding relationship with the first motion trajectory. For example, if the second motion trajectory is a spiral trajectory, the first motion trajectory is also a spiral trajectory.

[0066] It should be noted that the above-mentioned parameters such as reference height, focus compensation height, defocus feedback parameters, real-time focus height, etc. can all be optical path data, and different parameters can be superimposed, offset, etc.

[0067] By adopting the wafer image scanning system provided by the present application, the terminal device in the wafer image scanning system can detect the wafer defocus height of the wafer to be scanned carried on the moving table to obtain a reference height for focusing the wafer to be scanned; generate a first motion trajectory based on the position information of each feature point included in the wafer focus calibration data, and control the moving table to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory; obtain the focus compensation height of the wafer to be scanned when it moves to each feature point based on the wafer focus calibration data; obtain the defocus feedback parameters when the wafer to be scanned moves to each feature point, generate the real-time focus height when the wafer to be scanned moves to each feature point based on the reference height, the focus compensation height and the defocus feedback parameters, and focus the wafer to be scanned based on the real-time focus height to obtain the wafer image of the wafer to be scanned; the moving table in the wafer image scanning system can carry the wafer to be scanned to move. Therefore, the wafer image scanning system can compensate for the wafer defocus height in advance before scanning the wafer to be scanned based on the reference height and the focus compensation height of each feature point, and adjust the real-time focus height of the wafer to be scanned when it moves to each feature point through the real-time acquired defocus feedback parameters. It has high focus response speed and focus accuracy and strong applicability.

[0068] Embodiment 2

[0069] See also Figure 7 , Figure 7 It is a flow chart of a wafer image scanning method provided in an embodiment of the present application. Figure 7 The wafer image scanning method shown is applicable to Figure 1 For the convenience of description, the wafer image scanning system shown in the present application is described with the terminal device as the execution subject. Figure 7 As shown, the wafer image scanning method may include the following steps:

[0070] Step S101 , detecting a wafer defocus height of a wafer to be scanned that is carried on a moving stage, so as to obtain a reference height for tracking focus of the wafer to be scanned.

[0071] In some feasible implementations, the terminal device can detect the wafer to be scanned carried on the moving stage to obtain the reference height of the wafer to be scanned. The terminal device can obtain the initial image of the wafer to be scanned carried on the moving stage through the image acquisition device. The above initial image can be an image of the entire wafer, or an image of one or more scanning points in the wafer. The terminal device can input the above initial image into a reference height recognition model or other algorithm model that can recognize the reference height based on the image, and identify the initial height of the wafer. Specifically, the terminal device can first identify the wafer defocus height based on the initial image, for example, determine the wafer defocus height based on the diameter of the light spot caused by defocus in the initial image, and then obtain the reference height for tracking the focus of the wafer to be scanned based on the above wafer defocus height.

[0072] It should be noted that when detecting the reference height of the wafer to be scanned, the above-mentioned moving stage may move or not move. Optionally, if the moving stage does not move, the initial image obtained by the terminal device through the image acquisition device may be an image within the default shooting range of the image acquisition device. Optionally, the terminal device may determine one or more scanning points for identifying the wafer defocus height, and then control the moving stage to move to the position of the above-mentioned scanning point to obtain the initial image of the above-mentioned one or more scanning points through the image acquisition device. If the above-mentioned reference height is determined by the wafer defocus height of multiple scanning points, the calculation result of the wafer defocus height of the wafer to be scanned can be obtained based on the wafer defocus height of multiple scanning points, by calculating the average value of the wafer defocus height, and then obtaining the reference height for tracking the focus of the wafer to be scanned based on the calculation result of the above-mentioned wafer defocus height. Alternatively, multiple reference heights can be obtained respectively according to the wafer defocus height of multiple scanning points, and then the reference height for tracking the focus of the wafer to be scanned can be obtained by calculating the average value of the above-mentioned multiple reference heights.

[0073] Step S102 , generating a first motion trajectory based on position information of each feature point included in the wafer focus calibration data, and controlling the motion stage to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory.

[0074] In some feasible implementations, the terminal device may obtain the position information of each feature point from the wafer focus calibration data, and generate a first motion trajectory based on the distribution law between the position information of each feature point. For example, if the position information of each feature point indicates that multiple feature points are located in the same row in space (ie, the same ordinate), and the ordinate difference between different rows increases regularly, then the first motion trajectory generated based on the position information of each feature point in the wafer focus calibration data is a horizontal and vertical trajectory (ie, a Z-shaped trajectory). If the position information of each feature point indicates that multiple feature points are located in the same row in space (ie, the same ordinate), and the ordinate difference between different rows increases regularly, and the horizontal coordinate difference between multiple feature points in the same row is the same, then the first motion trajectory generated based on the position information of each feature point in the wafer focus calibration data is a square trajectory. If the position information of each feature point indicates that multiple feature points are located on the same circle, and the centers of different circles are the same, then the first motion trajectory generated based on the position information of each feature point in the wafer focus calibration data is a concentric circle trajectory. If the position information of each feature point indicates that multiple feature points are located on the same circle, and the centers of different circles are the same, and the distances between two adjacent feature points in the multiple feature points located on the same circle are equal, then the first motion trajectory generated based on the position information of each feature point in the wafer focus calibration data can be a polygonal trajectory. If the position information of each feature point indicates that multiple feature points are located on a spiral line, then the first motion trajectory generated based on the position information of each feature point in the wafer focus calibration data can be a spiral trajectory. It should be noted that if the position information of the above-mentioned multiple feature points indicates multiple possible motion trajectories, the specific first motion trajectory should be determined according to the actual product form or according to pre-set rules, and this application does not impose any restrictions on this.

[0075] In some feasible implementations, after the terminal device generates the first motion trajectory, it can control the motion stage to move based on the first motion trajectory, thereby driving the wafer to be scanned carried on the motion stage to move based on the first motion trajectory.

[0076] Step S103, based on the wafer focus calibration data, obtaining the focus compensation height of the wafer to be scanned when it moves to each scanning point, wherein the scanning point includes the feature point and non-feature points other than the feature point.

[0077] In some feasible implementations, the terminal device can obtain the focus compensation height of the wafer to be scanned when it moves to each scanning point based on the wafer focus calibration data. Specifically, when the terminal device controls the motion stage to move based on the first motion trajectory, the position information of the motion stage can be obtained in real time, that is, the position information of the wafer to be scanned can be obtained in real time. When the position information of the wafer to be scanned is the same as the position information of the feature point, it indicates that the wafer to be scanned has moved to the scanning point.

[0078] In some feasible implementations, the terminal device may obtain the focus compensation height based on the wafer focus calibration data according to the position information of the scanning point indicated by the wafer to be scanned. The storage form of the above-mentioned wafer focus calibration data may be a spatial two-dimensional focus compensation height table, a spatial two-dimensional focus compensation curve, or other forms that can store position information and the focus compensation height corresponding to the position information, and this application does not limit this.

[0079] It should be noted that the above-mentioned scanning points include the above-mentioned characteristic points and multiple non-characteristic points other than the characteristics. The above-mentioned characteristic points are used to scan the wafer to be scanned to obtain the wafer image, and the above-mentioned non-characteristic points are caused by the motion trajectory deviation caused by factors such as the motion error of the motion stage, which is different from the position information of the characteristic points planned by the first motion trajectory but has the same function. In other words, based on the planning of the first motion trajectory, the motion stage will move to the position of the characteristic point, but in the actual application scenario, there are factors such as motion errors, which cause the position information of the scanning point to which the motion stage actually moves to be different from the position information of the characteristic point. At this time, the scanning point where the motion stage is located is a non-characteristic point. If the moving platform moves to the above-mentioned non-feature point, the focus compensation height of the non-feature point can be calculated according to the target focus compensation height of the target feature point closest to the non-feature point, through the interpolation relationship between the target focus compensation height of the target feature point and its target position information (such as a linear relationship, multiple spline interpolation relationship, sine-cosine interpolation relationship, etc.), according to one or more interpolation calculation methods such as linear interpolation, multiple spline interpolation, sine-cosine interpolation, etc., where the terminal device can determine the interpolation calculation method based on the above-mentioned interpolation relationship and actual product requirements, and the present application does not limit the selected interpolation calculation method.

[0080] Step S104, obtaining the defocus feedback parameters of the wafer to be scanned when it moves to the above-mentioned scanning points, generating the real-time focusing height of the wafer to be scanned when it moves to the above-mentioned scanning points based on the above-mentioned reference height, the above-mentioned focus compensation height and the above-mentioned defocus feedback parameters, and focusing the wafer to be scanned based on the above-mentioned real-time focusing height to obtain the wafer image of the wafer to be scanned.

[0081] In some feasible implementations, the terminal device may also detect the wafer image obtained when the wafer to be scanned moves to each of the above-mentioned scanning points, and obtain the defocus feedback parameter based on the historical data recognition of the wafer image. The terminal device may generate the real-time focus height when the wafer to be scanned moves to each of the scanning points based on the above-mentioned reference height, focus compensation height and the above-mentioned defocus feedback parameter, and then adjust the focus height of the wafer to be scanned in real time based on the real-time focus height to focus, and obtain the wafer image of the wafer to be scanned.

[0082] It should be noted that the terminal device can identify the wafer defocus height of the wafer image obtained at the position of the previous feature point, and use the wafer defocus height of the previous wafer image as the defocus feedback parameter of the current feature point. In other words, the defocus feedback parameter is obtained based on the historical data of scanning the wafer to be scanned, which can be obtained based on the historical data of the previous wafer image, or based on the historical data of multiple wafer images scanned before the current feature point. This application does not impose any restrictions on this. If the current feature point is the first feature point to be scanned, that is, no other feature points are scanned before scanning the current feature point, and the historical data of the wafer defocus height is empty, then the defocus feedback parameter of the current feature point can be empty. For example, if the defocus feedback parameter is empty and the implementation focus height of the motion stage is obtained by superposition, the defocus feedback parameter can be set to "0".

[0083] The wafer image scanning method provided by the present application is adopted to obtain a reference height for focusing on the wafer to be scanned, and a first motion trajectory is generated based on the position information of each feature point included in the wafer focus calibration data to control the movement of the wafer to be scanned based on the first motion trajectory; based on the wafer focus calibration data, the focus compensation height of the wafer to be scanned when it moves to each feature point is obtained; the defocus feedback parameters when the wafer to be scanned moves to each feature point are obtained, and the wafer to be scanned is focused based on the reference height, the focus compensation height and the real-time focus height generated by the defocus feedback parameters to obtain the wafer image of the wafer to be scanned. Therefore, based on the reference height and the focus compensation height of each feature point, the wafer defocus height can be compensated in advance before scanning the wafer to be scanned, and the real-time focus height of the wafer to be scanned when it moves to each feature point can be adjusted in real time through the defocus feedback parameters obtained in real time, and the focus response speed and focus accuracy are high, and the applicability is strong.

[0084] Embodiment 3

[0085] See also Figure 8 , Figure 8 It is another flow chart of the wafer image scanning method provided in an embodiment of the present application. Figure 8 The wafer image scanning method shown is applicable to Figure 1 For the convenience of description, the wafer image scanning system shown in the present application is described with the terminal device as the execution subject. Figure 8 As shown, the wafer image scanning method may include the following steps:

[0086] Step S10 , controlling the moving stage to move based on a second motion trajectory to control the reference wafer carried on the moving stage to move based on the second motion trajectory.

[0087] In some feasible implementations, the terminal device can pre-plan and set the second motion trajectory according to the actual product form or application requirements, and then control the reference wafer carried on the moving table to move based on the second motion trajectory. The above-mentioned reference wafer can be an ultra-flat wafer. The surface flatness of the above-mentioned ultra-flat wafer is high, which can avoid the undulation error of the wafer surface introduced when detecting errors such as assembly errors of the moving table and parts processing errors, and can improve the accuracy of the detection results. The above-mentioned second motion trajectory includes one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygonal trajectory and a horizontal and vertical trajectory, or it can also be other types of motion trajectories, which are not limited in this application.

[0088] For ease of understanding, the description of the second motion trajectory may refer to the description of the spiral trajectory, concentric circle trajectory, square trajectory, polygonal trajectory and horizontal and vertical trajectory in the above embodiments, which will not be repeated here.

[0089] Step S20, obtaining the wafer defocus height and position information of the reference wafer moving to each feature point in the second motion trajectory, and determining the focus compensation height of each feature point in the second motion trajectory based on the wafer defocus height of each feature point.

[0090] In some feasible implementations, the terminal device can obtain the position information of the above-mentioned reference wafer in real time. When the position information of the reference wafer is the same as the position information of any feature point in the second motion trajectory, it indicates that the reference wafer has moved to any of the above-mentioned feature points. When the above-mentioned reference wafer moves to any of the above-mentioned feature points, the terminal device can obtain the wafer defocus height of the reference wafer. Specifically, the above-mentioned wafer defocus height can be determined by the diameter of the light spot generated by defocus in the wafer image of the reference wafer, or the wafer image of the above-mentioned reference wafer can be input into the wafer defocus height recognition model to identify the above-mentioned wafer defocus height. In some feasible implementations, the terminal device can generate a focus compensation height according to the wafer defocus height of any of the above-mentioned feature points. For example, if the wafer defocus height is -0.1cm, the focus compensation height can be +0.1cm. Among them, "+" and "-" are used to indicate the direction, and do not refer to the specific numerical value. "+" can be used to indicate the upper direction, "-" to indicate the lower direction, and "+" can be used to indicate the lower direction, and "-" can be used to indicate the upper direction. The present application does not limit this, and takes "+" to indicate the upper direction and "-" to indicate the lower direction as an example for explanation. If the above-mentioned focus compensation height is +0.1cm, it indicates that the moving stage should move upward by 0.1cm to achieve the focus of the wafer to be scanned at the feature point. The terminal device can move with the moving stage based on the second motion trajectory, and each time it moves to a feature point, it obtains the wafer defocus height, position information and focus compensation height of the feature point, until the position information and focus compensation height of all feature points are obtained. Among them, the terminal device can scan the reference wafer once or multiple times.

[0091] Step S301, generating a spatial two-dimensional focus compensation height table based on the position information of each feature point and the focus compensation height, and using the focus compensation height table as wafer focus calibration data.

[0092] Optionally, in some feasible implementations, after the terminal device obtains the position information of each feature point and the focus compensation height corresponding to the position information, it can generate a spatial two-dimensional focus compensation height table based on the position information and the focus compensation height. One dimension of the spatial two-dimensional focus compensation height table is used to store the position information of each feature point, and the other dimension is used to record the focus compensation height of each feature point. The above-mentioned two-dimensional focus compensation height table stores the position information and the focus compensation height to match the second motion trajectory.

[0093] Take the second motion trajectory as the horizontal and vertical trajectory as an example, see Fig. 9 , Fig. 9 This is a schematic diagram of the spatial two-dimensional focus tracking compensation height provided by the embodiment of the present application. Fig. 9 As shown, the spatial two-dimensional focus compensation altimeter records each feature point through horizontal and vertical tracks ( Fig. 9Only one feature point is displayed in the figure), the horizontal and vertical tracks ( Fig. 9 The focus compensation height corresponding to the position information is recorded at each feature point in the image (only part of the horizontal and vertical tracks are shown in the figure). The position information of the above feature points can be recorded in Cartesian coordinates or polar coordinates. Taking Cartesian coordinates as an example, the position information of the above feature points can be stored in the form of (x, y), where x is the horizontal coordinate and y is the vertical coordinate. If the position information of the feature point is stored as (1, 1), it indicates that the feature point is located at a position where the horizontal coordinate is 1 and the vertical coordinate is 1 in the coordinate axis of the reference wafer in space. The position of the origin of the above coordinate axis can be determined according to the actual form of the product, for example, the center of the circle is used as the origin of the coordinate axis, and this application does not impose any restrictions on this. Fig. 9 The spatial two-dimensional focus compensation height table shown also includes the focus compensation height of the feature points. Fig. 9 The above focus compensation height can be represented by "+" or "-" to indicate the direction, for example, "+" can indicate the upward direction and "-" can indicate the downward direction. For example, if the focus compensation height is stored as +0.1cm, it indicates that the motion stage should move upward by 0.1cm to perform the focusing operation.

[0094] In some feasible implementations, the above-mentioned spatial two-dimensional focus compensation height table may also store motion trajectories such as spiral trajectories, concentric circle trajectories, square trajectories, horizontal and vertical trajectories, and polygonal trajectories, wherein different motion trajectories generate different spatial two-dimensional focus compensation height tables, that is, one motion trajectory may correspond to one spatial two-dimensional focus compensation height table. Therefore, the terminal device may also determine the first motion trajectory based on the motion trajectory stored in the spatial two-dimensional focus compensation height table. The terminal device may use the above-mentioned spatial two-dimensional focus compensation height table as wafer focus calibration data, and then generate the estimated focus compensation height at each feature point position before scanning the wafer to be scanned.

[0095] Step S302: Generate a spatial two-dimensional focus compensation curve based on the position information of each feature point and the focus compensation height, and use the focus compensation curve as wafer focus calibration data.

[0096] Optionally, in some feasible implementations, after the terminal device obtains the position information of each feature point and the focus compensation height corresponding to the position information, it can also generate a spatial two-dimensional focus compensation curve based on the above position information and the focus compensation height, and then the above spatial two-dimensional focus compensation curve can be used as wafer focus calibration data. One dimension of the spatial two-dimensional focus compensation curve is used to store the position information of each feature point, and the other dimension is used to record the focus compensation height of each feature point. The focus compensation height curve can be a calculation formula that can indicate the interpolation relationship between position information and focus compensation height, such as a polynomial equation, a sine-cosine equation, an exponential equation, etc., and the present application does not impose any restrictions on this.

[0097] Taking the polynomial equation as an example, the terminal device can obtain the interpolation relationship between the position information of each feature point and the focus compensation height, and then determine the parameters in the polynomial equation, and generate a spatial two-dimensional focus compensation curve based on the above interpolation relationship. Among them, the position information can be used as the independent variable of the above polynomial equation, and the focus compensation height can be used as the dependent variable of the above polynomial equation. One position information corresponds to one focus compensation height. Therefore, based on the spatial two-dimensional focus compensation curve, the terminal device can calculate the focus compensation height corresponding to the position information by inputting the position information of the feature point.

[0098] Step S40 , detecting the wafer defocus height of the wafer to be scanned on the moving stage to obtain a reference height for tracking the focus of the wafer to be scanned.

[0099] In some feasible implementations, the moving stage may also carry a wafer to be scanned. The terminal device may detect the wafer defocus height of the wafer to be scanned, and then determine a reference height for tracking the focus of the wafer to be scanned based on the wafer defocus height. For ease of understanding, the implementation of step S40 may be referred to the description of step S101, which will not be repeated here.

[0100] Step S50, generating a first motion trajectory based on the position information of each feature point included in the wafer focus calibration data, and controlling the motion stage to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory.

[0101] In some feasible implementations, the terminal device may obtain the position information of each feature point from the wafer focus calibration data, and based on the above position information, the type of the second motion trajectory used when generating the wafer focus calibration data may be determined, and then the first motion trajectory may be generated. Among them, the first motion trajectory may be one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygonal trajectory, and a horizontal and vertical trajectory, and the type of the first motion trajectory corresponds to the type of the second motion trajectory. For example, if the second motion trajectory is a concentric circle trajectory, the first motion trajectory is also a concentric circle trajectory. For ease of understanding, the implementation method of the above step S50 can be referred to the description of the above step S102, which will not be repeated here.

[0102] Step S60, obtaining the focus compensation height of the wafer to be scanned when it moves to each scanning point based on the wafer focus calibration data.

[0103] In some feasible implementations, the terminal device may obtain the focus compensation height of the wafer to be scanned when it moves to each scanning point based on the above position information and through the wafer focus calibration data. Among them, each scanning point includes each feature point and multiple non-feature points other than each feature point. The terminal device may first obtain the focus compensation height of each feature point, and then determine the focus compensation height of each non-feature point through an interpolation algorithm or the like. Specifically, the terminal device may obtain the position information of the wafer to be scanned in real time during the movement of the wafer to be scanned. When the position information of the wafer to be scanned is the same as the position information of any feature point stored in the wafer focus calibration data, it is determined that the wafer to be scanned has moved to the position of the feature point, and the focus compensation height may be obtained according to the position information of the feature point. Optionally, the terminal device may also obtain the focus compensation height of the next feature point when the wafer to be scanned moves to the current feature point. For example, the position information of the next feature point sorted according to the motion order of the first motion trajectory can be obtained from the wafer focus calibration data, and the focus compensation height of the next feature point can be obtained based on the position information of the next feature point. Then, before focusing on the next feature point, the motion stage can be controlled to compensate for the wafer defocus height to achieve fast focusing.

[0104] Optionally, if the above-mentioned wafer focus calibration data is a spatial two-dimensional focus compensation height table, the terminal device can query the focus compensation heights corresponding to each position information from the spatial two-dimensional focus compensation height table according to the position information of the wafer to be scanned moving to each feature point, and use the queried focus compensation heights as the focus compensation heights of the wafer to be scanned at each feature point.

[0105] Optionally, if the above-mentioned wafer focus calibration data is a spatial two-dimensional focus compensation curve, the terminal device can calculate the focus compensation heights corresponding to each position information based on the spatial two-dimensional focus compensation curve according to the position information of the wafer to be scanned moving to each feature point, and use the queried focus compensation heights as the focus compensation heights of the wafer to be scanned at each feature point.

[0106] In some feasible implementations, the terminal device can determine the focus compensation height of the non-feature point by interpolation calculation methods such as linear interpolation, multiple spline interpolation, sine and cosine interpolation, etc. The terminal device can obtain the target position information of the target feature point closest to the non-feature point based on the position information of the non-feature point, and then obtain the target focus compensation height of the target feature point according to the target position information of the target feature point. For example, if the first motion trajectory includes a non-feature point and two feature points, wherein the position information of the non-feature point is (1, 1), the position information of the first feature point is (1, 2), and the position information of the second feature point is (1, 3), then the distance between the first feature point and the non-feature point is one basic unit, and the distance between the second feature point and the non-feature point is two basic units. The first feature point is the feature point closest to the non-feature point in the first motion trajectory, so the terminal device can determine the first feature point as the target feature point. Furthermore, the terminal device can calculate the focus compensation height corresponding to the position information of the non-feature point according to the above-mentioned linear interpolation, multiple spline curve interpolation, sine and cosine interpolation and other interpolation calculation methods, so as to adjust the height of the motion stage based on the focus compensation height of the non-feature point, so that the motion stage can move smoothly and quickly reach the height of the feature point at which the wafer to be scanned is focused. For ease of understanding, the implementation method of the above-mentioned step S60 can be referred to the description of the above-mentioned step S103, which will not be repeated here.

[0107] Step S70, obtaining the defocus feedback parameters of the wafer to be scanned when it moves to each of the scanning points, generating the real-time focusing height of the wafer to be scanned when it moves to each of the scanning points based on the reference height, the focus compensation height and the defocus feedback parameters, and focusing the wafer to be scanned based on the real-time focusing height to obtain the wafer image of the wafer to be scanned.

[0108] In some feasible implementations, the terminal device can obtain the defocus feedback parameters of the wafer to be scanned when it moves to each scanning point in real time, and then generate a real-time focus height. Fig.10 , Fig.10 Schematic diagram of the generation process of real-time focus height provided by the embodiment of the present application. The terminal device can detect the position information and defocus feedback parameters (i.e., defocus feedback parameters) of the moving platform in real time during the movement of the moving platform, so as to compensate the focus error during the movement of the moving platform based on the defocus feedback parameters. Fig.10 As shown, the terminal device can calculate the superimposed height of the reference height, focus compensation height, and defocus feedback parameters of the wafer to be scanned at any scanning point, and determine the superimposed height as the real-time focus height when the wafer to be scanned moves to any scanning point, so as to generate the real-time focus height when the wafer to be scanned moves to each scanning point.

[0109] The terminal device can control the motion of the motion stage based on the real-time focus height to focus on the wafer to be scanned, for example, generate a motion control instruction based on the real-time focus height to trigger the motion stage to move to the real-time focus height, and then focus and scan the wafer to be scanned to obtain a wafer image. For ease of understanding, the implementation of the above step S70 can be referred to the description of the above step S104, which will not be repeated here.

[0110] Step S80, determining whether the wafer scanning is completed.

[0111] In some feasible implementations, the terminal device may determine whether the wafer scanning is completed. For example, the terminal device may determine based on the scanning conditions of each scanning point in the first motion trajectory. If the terminal device detects that all scanning points included in the first motion trajectory have been scanned, it is determined that the wafer scanning is completed and step S90 is executed; if the terminal device detects that there are unscanned scanning points in the first motion trajectory, it is determined that the wafer scanning is not completed and step S60 is executed.

[0112] Step S90, obtaining a wafer image.

[0113] In some feasible implementations, if the terminal device determines that the wafer scanning is completed, the wafer image obtained at each scanning point can be processed to obtain a complete wafer image.

[0114] By adopting the wafer image scanning method provided by the present application, the wafer defocus height of the wafer to be scanned carried on the moving stage can be detected to obtain the reference height for tracking the focus of the wafer to be scanned; a first motion trajectory is generated based on the position information of each feature point included in the wafer focus calibration data, and the moving stage is controlled to move based on the z first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory; the tracking focus compensation height of the wafer to be scanned moving to each scanning point is obtained based on the wafer focus calibration data; the defocus feedback parameters when the wafer to be scanned moves to each scanning point are obtained, and the real-time focusing height when the wafer to be scanned moves to each scanning point is generated based on the reference height, the tracking focus compensation height and the defocus feedback parameters, and the wafer to be scanned is focused based on the real-time focusing height to obtain the wafer image of the wafer to be scanned. Therefore, the wafer defocus height can be compensated in advance before scanning the wafer to be scanned based on the reference height and the tracking focus compensation height of each scanning point, and the real-time focusing height when the wafer to be scanned moves to each scanning point is adjusted in real time by the defocus feedback parameters obtained in real time, and the focusing response speed and focusing accuracy are high, and the applicability is strong.

[0115] Embodiment 4

[0116] See also Fig.11 , Fig.11 Schematic diagram of the structure of the wafer image scanning device provided in the embodiment of the present application. Fig.11 The wafer image scanning device 10 shown may be a computer device having a computer program (including program code) for implementing the above-mentioned wafer image scanning method. The wafer image scanning device 10 may also be a computer program, for example, the computer program is an application software. The device may be used to execute the corresponding steps in the wafer image scanning method provided in the embodiment of the present application. Fig.11 As shown, the wafer image scanning device 10 may include: a detection module 101 , a generation module 102 , an acquisition module 103 and a focus module 104 .

[0117] The detection module 101 is used to detect the wafer defocus height of the wafer to be scanned carried on the moving stage to obtain a reference height for tracking the focus of the wafer to be scanned;

[0118] A generating module 102, configured to generate a first motion trajectory based on the position information of each feature point included in the wafer focus calibration data, and control the motion stage to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory;

[0119] An acquisition module 103 is used to acquire the focus compensation height of the wafer to be scanned when it moves to each scanning point based on the wafer focus calibration data, wherein the scanning point includes the feature point and non-feature points other than the feature point;

[0120] The focusing module 104 is used to obtain the defocus feedback parameters when the wafer to be scanned moves to the above-mentioned scanning points, generate the real-time focusing height when the wafer to be scanned moves to the above-mentioned scanning points based on the above-mentioned reference height, the above-mentioned focus compensation height and the above-mentioned defocus feedback parameters, and focus the wafer to be scanned based on the above-mentioned real-time focusing height to obtain the wafer image of the wafer to be scanned.

[0121] The specific functions implemented by the detection module 101 can be found in the Figure 7 In the corresponding embodiment, step S101, or, you can participate in the above Figure 8 The specific functions implemented by the above-mentioned generating module 102 can be found in the above-mentioned step S40 in the corresponding embodiment. Figure 7 Step S102 in the embodiment shown, or, refer to the above Figure 8 Step S50 in the embodiment shown; the specific functions implemented by the acquisition module 103 can be found in the above Figure 7 In the embodiment shown in FIG. 1 , step S103 may be referred to above. Figure 8 In the embodiment shown, step S60; the specific functions implemented by the focusing module 104 can be found in the above Figure 7 In the embodiment shown in FIG. 1 , step S104 may be referred to above. Figure 8 Step S70 in the illustrated embodiment is not described in detail.

[0122] Embodiment 5

[0123] See also Fig.12 , Fig.12 Schematic diagram of the structure of the terminal device provided in the embodiment of the present application. Fig.12 As shown, the terminal device 100 may include: a processor 1001, a network interface 1004, a memory 1005 and a controller 1006. In addition, the terminal device 100 may also include: a user interface 1003, and at least one communication bus 1002. The communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1005 includes a random access memory (random access memory, RAM) and a non-volatile memory (non-volatile memory, NVM), such as an erasable programmable read-only memory (erasable programmable read-only memory, EPROM). The memory 1005 may also be at least one storage device located away from the aforementioned processor 1001. The controller 1006 can be used to receive data sent by the processor and generate control instructions to control devices such as a motion platform and an image acquisition device, and can execute the above Figures 2 to 5 The functions implemented by the controller involved in the illustrated embodiment. Optionally, the controller 1006 may be a motion controller or other types of controllers, which should be determined according to the actual application scenario. This application only takes the motion controller as an example for illustration. Fig.12 As shown, the memory 1005 as a computer-readable storage medium may include an operating system, a network communication module, a user interface module, and a device control application. Figure 1 The processor 1001 described in this embodiment can execute the above Figure 1 The functions performed by the processor provided in the illustrated embodiment.

[0124] In such Fig.12 In the terminal device 100 shown, the network interface 1004 can provide a network communication function; the user interface 1003 is mainly used to provide an input interface for the user; and the processor 1001 can be used to call the device control application stored in the memory 1005 to implement the aforementioned Figures 7 to 10 The wafer image scanning method in the illustrated embodiment.

[0125] It should be understood that the terminal device 100 described in the embodiment of the present application can execute the above Figures 7 to 10 The wafer image scanning method of the embodiment shown will not be described in detail. In addition, the beneficial effects of the same method will not be described in detail.

[0126] In addition, it should be pointed out here that: the embodiment of the present application also provides a computer-readable storage medium, and the computer-readable storage medium stores a computer program executed by the wafer image scanning method mentioned above, and the computer program includes program instructions. When the processor executes the program instructions, the above-mentioned Figures 7 to 10 The above-mentioned wafer image scanning method provided by the illustrated embodiment is therefore not described in detail. In addition, the description of the beneficial effects of adopting the same method is not described in detail. For technical details not disclosed in the computer-readable storage medium embodiment involved in this application, please refer to the description of the method embodiment of this application.

[0127] The computer-readable storage medium may be the wafer image scanning method provided in any of the aforementioned embodiments or the internal storage unit of the terminal device, such as a hard disk or memory of the terminal device. The computer-readable storage medium may also be an external storage device of the terminal device, such as a plug-in hard disk, a smart memory card (smart media card, SMC), a secure digital (secure digital, SD) card, a flash card (flash card), etc. equipped on the terminal device. Further, the computer-readable storage medium may also include both the internal storage unit of the terminal device and an external storage device. The computer-readable storage medium is used to store the computer program and other programs and data required by the terminal device. The computer-readable storage medium may also be used to temporarily store data that has been output or is to be output.

[0128] In addition, it should be noted that: the embodiment of the present application also provides a computer program product or a computer program, the computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the terminal device loads and executes the computer instructions, so that the terminal device can execute the above Figures 7 to 10 The method provided by the illustrated embodiment.

[0129] Those skilled in the art will appreciate that the systems and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Professional and technical personnel may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

Claims

1. A wafer image scanning method, characterized in that: include: Detecting a wafer defocus height of a wafer to be scanned carried on a moving stage to obtain a reference height for tracking focus of the wafer to be scanned; Generate a first motion trajectory based on position information of each feature point included in the wafer focus calibration data, and control the motion stage to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory; Based on the wafer focus calibration data, obtaining the focus compensation height of the wafer to be scanned when it moves to each scanning point, wherein the scanning point includes the feature point and non-feature points other than the feature point; Defocus feedback parameters are obtained when the wafer to be scanned moves to each scanning point, and real-time focusing heights are generated when the wafer to be scanned moves to each scanning point based on the reference height, the focus compensation height and the defocus feedback parameters, and the wafer to be scanned is focused based on the real-time focusing height to obtain a wafer image of the wafer to be scanned.

2. The method according to claim 1, characterized in that The step of obtaining the focus compensation height of the wafer to be scanned when it moves to each scanning point based on the wafer focus calibration data includes: The focus compensation height of the wafer to be scanned when it moves to each feature point is obtained from the wafer focus calibration data, and the focus compensation height of the wafer to be scanned when it moves to the non-feature point is obtained based on the focus compensation height of each feature point, so as to obtain the focus compensation height of the wafer to be scanned when it moves to each scanning point.

3. The method according to claim 2, characterized in that The step of obtaining the focus compensation height of the wafer to be scanned moving to the non-feature point based on the focus compensation height of each feature point includes: When the wafer to be scanned moves to any non-feature point other than the feature points, a target feature point closest to the non-feature point is determined from the feature points; The target focus compensation height and target position information of the target feature point are obtained from the wafer focus calibration data, and the focus compensation height of any non-feature point is obtained based on the interpolation relationship between the target focus compensation height and the target position information to obtain the focus compensation height of each non-feature point.

4. The method according to any one of claims 1 to 3, characterized in that: The method of generating the real-time focus height when the wafer to be scanned moves to each scanning point based on the reference height, the focus compensation height and the defocus feedback parameter comprises: Calculate the superimposed height of the reference height, the focus compensation height and the defocus feedback parameter of any scanning point, and determine the superimposed height as the real-time focus height when the wafer to be scanned moves to any scanning point, so as to generate the real-time focus height when the wafer to be scanned moves to each scanning point.

5. The method according to any one of claims 1 to 3, characterized in that: Before detecting the wafer defocus height of the wafer to be scanned carried on the moving stage, the method further includes: Controlling the motion stage to move based on a second motion trajectory to control the reference wafer carried on the motion stage to move based on the second motion trajectory, obtaining the wafer defocus height and position information of the reference wafer moving to each feature point in the second motion trajectory, and determining the focus compensation height of each feature point in the second motion trajectory based on the wafer defocus height of each feature point; Generate wafer focus calibration data based on the position information of each feature point and the focus compensation height; Wherein, the second motion trajectory includes one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygonal trajectory and a horizontal and vertical trajectory.

6. The method according to claim 5, characterized in that The step of generating wafer focus calibration data based on the position information of each feature point and the focus tracking compensation height includes: A spatial two-dimensional focus compensation height table is generated based on the position information of each feature point and the focus compensation height, and the focus compensation height table is used as wafer focus calibration data, wherein one dimension in the spatial two-dimensional focus compensation height table is used to store the position information of each feature point, and another dimension in the spatial two-dimensional focus compensation height table is used to record the focus compensation height of each feature point.

7. The method according to claim 5, characterized in that The step of generating wafer focus calibration data based on the position information of each feature point and the focus tracking compensation height includes: A spatial two-dimensional focus compensation curve is generated based on the position information of each feature point and the focus compensation height, and the focus compensation curve is used as wafer focus calibration data, wherein one dimension of the spatial two-dimensional focus compensation curve is used to store the position information of each feature point, and another dimension of the spatial two-dimensional focus compensation curve is used to record the focus compensation height of each feature point.

8. The method according to claim 7, characterized in that The step of obtaining the focus compensation height of the wafer to be scanned when it moves to each feature point from the wafer focus calibration data includes: When the wafer to be scanned moves to any feature point among the feature points, the position information of the feature point is obtained, and the focus compensation height of the feature point is calculated based on the position information of the feature point and the spatial two-dimensional focus compensation curve to obtain the focus compensation height of each feature point.

9. A wafer image scanning device, characterized in that: include: A detection module, used for detecting a wafer defocus height of a wafer to be scanned carried on a moving stage, so as to obtain a reference height for tracking focus of the wafer to be scanned; A generating module, configured to generate a first motion trajectory based on position information of each feature point included in the wafer focus calibration data, and control the motion stage to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory; An acquisition module, configured to acquire a focus compensation height of the wafer to be scanned when the wafer moves to each scanning point based on the wafer focus calibration data, wherein the scanning point includes the feature point and non-feature points other than the feature point; A focusing module is used to obtain defocus feedback parameters when the wafer to be scanned moves to each scanning point, generate a real-time focusing height when the wafer to be scanned moves to each scanning point based on the reference height, the focus compensation height and the defocus feedback parameters, and focus the wafer to be scanned based on the real-time focusing height to obtain a wafer image of the wafer to be scanned.

10. A terminal device, characterized in that: include: Processor and memory; The processor is connected to the memory, wherein the memory is used to store program codes, and the processor is used to call the program codes to execute any one of the methods described in claims 1-8.

11. A wafer image acquisition system, characterized in that: include: A moving table and a terminal device as claimed in claim 10; wherein the moving table is used to carry wafers.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is suitable for being loaded by a processor and executing the method according to any one of claims 1 to 8.

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