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

Abstract

Embodiments of the present application disclose a wafer image scanning method and device, a terminal device and a readable storage medium. The method comprises: detecting a wafer defocus height of a wafer to be scanned carried on a moving table to obtain a reference height for focus pursuit of 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 to control the wafer to be scanned to move based on the first motion trajectory; obtaining a focus pursuit compensation height of the wafer to be scanned when moving to each scanning point based on the wafer focus calibration data; obtaining a defocus feedback parameter when the wafer to be scanned moves to each scanning point, generating a real-time focus height of the wafer to be scanned when moving to each scanning point based on the reference height, the focus pursuit 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. The response speed of the focusing is fast, the focusing precision is high, and the applicability is strong.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, and particularly relates to a wafer image scanning method and device, a terminal device and a readable storage medium. BACKGROUND

[0002] Semiconductor detection technology plays an important role in the processes of semiconductor design, production, packaging and testing, and is a key to improving the yield of semiconductor production. When detecting a wafer semiconductor, an ultra-high resolution linear array camera is often used to scan the wafer to obtain a wafer image, so that defect detection is performed based on the wafer image. With the rapid development of semiconductor technology, the process shrinkage of semiconductor chips, and the improvement of the precision and resolution of semiconductor defect detection, more accurate and faster focusing is required when collecting a wafer image to avoid problems such as defocus, blur or virtualization of the collected wafer image, thereby resulting in low wafer detection accuracy. Therefore, how to focus quickly and prevent defocus is crucial to semiconductor defect detection.

[0003] In the prior art, in the scanning process of the wafer, focusing is to detect the defocus amount of the scanning feature point in real time when the motion table moves to the scanning feature point, and then to control the motion of the motion table based on the real-time detected defocus amount to realize real-time focusing. However, in the prior art, the process of controlling the motion of the motion table based on the real-time detected defocus amount has a long chain from defocus amount detection to focusing, and a large delay, resulting in slow focusing response, poor performance, and low focusing accuracy and poor applicability when the fluctuation distance of the wafer surface exceeds the focus distance. SUMMARY

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

[0005] In a first aspect, the embodiments of the present application provide a wafer image scanning method, comprising: detecting a wafer defocus height of a to-be-scanned wafer carried on a moving table to obtain a reference height for focus pursuit of the to-be-scanned wafer; 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 to-be-scanned wafer to move based on the first motion trajectory; obtaining a focus pursuit compensation height of the to-be-scanned wafer when moving to each scanning point based on the wafer focus calibration data, wherein the scanning points include the feature points and non-feature points other than the feature points; obtaining a defocus feedback parameter when the to-be-scanned wafer moves to each scanning point, generating a real-time focus height of the to-be-scanned wafer when moving to each scanning point based on the reference height, the focus pursuit compensation height, and the defocus feedback parameter, and focusing the to-be-scanned wafer based on the real-time focus height to obtain a wafer image of the to-be-scanned wafer. By using the present application, the wafer defocus height can be compensated in advance before scanning the to-be-scanned wafer based on the reference height and the focus pursuit compensation height of each scanning point, and the real-time focus height of the to-be-scanned wafer when moving to each scanning point is adjusted in real time through the real-time obtained defocus feedback parameter, so that the focus response speed and the focus accuracy can be improved, and the applicability is strong.

[0006] In a possible implementation of the first aspect, the obtaining of the focus pursuit compensation height of the to-be-scanned wafer when moving to each scanning point based on the wafer focus calibration data comprises: obtaining the focus pursuit compensation height of the to-be-scanned wafer when moving to each feature point from the wafer focus calibration data, and obtaining the focus pursuit compensation height of the to-be-scanned wafer when moving to each non-feature point based on the focus pursuit compensation height of each feature point, to obtain the focus pursuit compensation height of the to-be-scanned wafer when moving to each scanning point. By using the present application, the focus pursuit compensation height of the non-feature point can be obtained through the focus pursuit compensation height of the feature point, which can be applicable to the case where the focus pursuit compensation height cannot be directly obtained from the wafer focus calibration data based on the position information of the non-feature point, so that the applicability is improved.

[0007] In a possible implementation of the first aspect, the obtaining of the focus compensation height of each non-feature point based on the focus compensation height of each feature point comprises: determining a target feature point closest to any non-feature point from the feature points when the wafer to be scanned moves to the non-feature point; obtaining target focus compensation height and target position information of the target feature point from the wafer focusing calibration data, and obtaining the focus compensation height of the non-feature point based on an interpolation relationship between the target focus compensation height and the target position information to obtain the focus compensation height of each non-feature point. According to the application, the focus compensation height of the non-feature point is calculated based on the interpolation relationship between the target focus compensation height and the target position information of the target feature point closest to the non-feature point, and a suitable interpolation calculation method can be selected according to product requirements and the interpolation relationship, so that the focusing accuracy is higher and the applicability is stronger.

[0008] In a possible implementation of the first aspect, the generating of the real-time focusing height of the wafer to be scanned when moving to each scanning point based on the reference height, the focus compensation height, and the defocus feedback parameter comprises: calculating the superimposed height of the reference height, the focus compensation height, and the defocus feedback parameter of any scanning point, determining the superimposed height as the real-time focusing height of the wafer to be scanned when moving to the scanning point, and generating the real-time focusing height of the wafer to be scanned when moving to each scanning point. According to the 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 motion stage can be adjusted in real time based on the real-time focusing height to eliminate the error in the focusing process, so that the focusing accuracy and the applicability can be further improved.

[0009] In a possible implementation of the first aspect, before the detecting of the wafer defocus height of the wafer to be scanned carried on the motion stage, the method further comprises: 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 wafer defocus height and position information of the reference wafer when 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; generating wafer focusing calibration data based on the position information and the focus compensation height of each feature point; and wherein the second motion trajectory comprises one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygon trajectory, and a horizontal and vertical trajectory. According to the application, the reference wafer can be scanned before the wafer to be scanned is scanned, and then the wafer focusing calibration data is obtained to predict the focus compensation height of each scanning point in the scanning process of the wafer to be scanned, so that the compensation can be made in advance through prediction, the focusing time of the wafer to be scanned can be further shortened, and the focusing response speed can be improved.

[0010] In a possible implementation of the first aspect, the wafer focus calibration data is generated based on the position information of the feature points and the focus compensation heights, including: generating a two-dimensional spatial focus compensation height table based on the position information of the feature points and the focus compensation heights, and taking the two-dimensional spatial focus compensation height table as the wafer focus calibration data, wherein one dimension of the two-dimensional spatial focus compensation height table is used to store the position information of the feature points, and the other dimension of the two-dimensional spatial focus compensation height table is used to record the focus compensation heights of the feature points. According to the application, the two-dimensional spatial focus compensation height table can be generated to quickly obtain the focus compensation height corresponding to the position information according to the position information, so that the focus response speed can be further improved, 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 feature points and the focus compensation heights, including: generating a two-dimensional spatial focus compensation height table based on the position information of the feature points and the focus compensation heights, and taking the two-dimensional spatial focus compensation height table as the wafer focus calibration data, wherein one dimension of the two-dimensional spatial focus compensation height table is used to store the position information of the feature points, and the other dimension of the two-dimensional spatial focus compensation height table is used to record the focus compensation heights of the feature points. According to the application, the two-dimensional spatial focus compensation height table can be generated to quickly obtain the focus compensation height corresponding to the position information according to the position information, so that the focus response speed can be further improved, and the applicability is strong.

[0012] In a possible implementation of the first aspect, the focus compensation height of the wafer to be scanned moving to the feature points is obtained from the wafer focus calibration data, including: when the wafer to be scanned moves to any feature point of the feature points, obtaining the position information of the any feature point, calculating the focus compensation height of the any feature point based on the position information of the any feature point and the two-dimensional spatial focus compensation height table, to obtain the focus compensation height of the feature points. According to the application, the two-dimensional spatial focus compensation height table can be generated to quickly calculate the focus compensation height corresponding to the position information according to the position information, so that the focus response speed can be further improved, and the applicability is strong.

[0013] In a possible implementation of the first aspect, the wafer focus calibration data is generated based on the position information of the feature points and the focus compensation heights, including: generating a two-dimensional spatial focus compensation height table based on the position information of the feature points and the focus compensation heights, and taking the two-dimensional spatial focus compensation height table as the wafer focus calibration data, wherein one dimension of the two-dimensional spatial focus compensation height table is used to store the position information of the feature points, and the other dimension of the two-dimensional spatial focus compensation height table is used to record the focus compensation heights of the feature points. According to the application, the two-dimensional spatial focus compensation height table can be generated to quickly obtain the focus compensation height corresponding to the position information according to the position information, so that the focus response speed can be further improved, and the applicability is strong.

[0014] In a possible implementation of the first aspect, the wafer focus calibration data is generated based on the position information of the feature points and the focus compensation heights, including: generating a two-dimensional spatial focus compensation height table based on the position information of the feature points and the focus compensation heights, and taking the two-dimensional spatial focus compensation height table as the wafer focus calibration data, wherein one dimension of the two-dimensional spatial focus compensation height table is used to store the position information of the feature points, and the other dimension of the two-dimensional spatial focus compensation height table is used to record the focus compensation heights of the feature points. According to the application, the two-dimensional spatial focus compensation height table can be generated to quickly obtain the focus compensation height corresponding to the position information according to the position information, so that the focus response speed can be further improved, and the applicability is strong.

[0015] detecting a wafer defocus height of a wafer to be scanned carried on a motion stage to obtain a reference height for focus pursuit of the wafer to be scanned;

[0016] generating a first motion trajectory based on position information of each feature point included in 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;

[0017] obtaining focus pursuit compensation heights of the wafer to be scanned moving to each scanning point based on the wafer focus calibration data, wherein the scanning points include the feature points and non-feature points other than the feature points;

[0018] focusing, obtaining defocus feedback parameters of the wafer to be scanned moving to each scanning point, generating real-time focus heights of the wafer to be scanned moving to each scanning point based on the reference height, the focus pursuit compensation heights and the defocus feedback parameters, and focusing the wafer to be scanned based on the real-time focus heights to obtain wafer images of the wafer to be scanned.

[0019] In a third aspect, an embodiment of the present application provides a terminal device, including a processor and a memory, the processor being connected to the memory, the memory being configured to store program code, and the processor being configured to invoke the program code to execute the wafer image scanning method provided in the first aspect or any possible implementation manner of the first aspect.

[0020] In a fourth aspect, an embodiment of the present application provides a wafer image scanning system, including a motion stage and a terminal device provided in the third aspect, the motion stage being configured to carry a wafer.

[0021] In a fifth aspect, an embodiment of the present application provides a computer readable storage medium, the computer readable storage medium storing a computer program, the computer program being adapted to be loaded by a processor and execute the wafer image scanning method provided in the first aspect or any possible implementation manner of the first aspect.

[0022] In a sixth aspect, an embodiment of the present application provides a computer program product, the computer program product containing computer instructions, the computer instructions being adapted to be loaded by a processor and execute the wafer image scanning method provided in the first aspect or any possible implementation manner of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0025] Figure 3 is a concentric circle trajectory schematic diagram provided by an embodiment of the present application;

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

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

[0028] Figure 6 is a square trajectory schematic diagram provided by an embodiment of the present application;

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

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

[0031] Figure 9 is a space two-dimensional focus pursuit compensation height representation diagram provided by an embodiment of the present application;

[0032] Figure 10 is a generation flowchart of a real-time focus height provided by an embodiment of the present application;

[0033] Figure 11 is a structure schematic diagram of a wafer image scanning device provided by an embodiment of the present application;

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

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

[0036] For ease of understanding, first, some nouns are simply explained as follows:

[0037] 1. Feature point, which can also be referred to as ideal feature point or target feature point, can be a mark pattern used for alignment, or the upper left corner of a Die, and needs to have unique features that are easy to identify. It can be selected from feature points used for wafer alignment, or obtained through artificial intelligence annotation in a wafer map. In the embodiments of the present application, the first motion trajectory of the wafer to be scanned and the second motion trajectory of the reference wafer each include a plurality of feature points.

[0038] 2. Reference height, the initial height caused by the thickness of the wafer or the thickness of the motion stage, can be used to preliminarily focus the wafer based on the reference height.

[0039] 3. Wafer defocus height, also known as defocus amount, refers to the data indicating the defocus deviation when the wafer image is acquired during the scanning process of the wafer, which can be used to adjust the distance between the wafer to be detected and the image acquisition device to make the image reach the preset sharpness. The preset sharpness refers to the specified value of the wafer image sharpness, which can be determined according to the specific form of the product.

[0040] 3. Focus compensation height, which is the data used to compensate for the wafer defocus height, that is, the compensation value of focus pursuit. By adjusting the height of the motion stage through the focus compensation height, the wafer to be scanned can be adjusted to the focus state where the acquired image reaches the preset sharpness.

[0041] 4. Proportional-Integral-Derivative Controller (PID Controller). The PID controller includes proportional, integral and derivative parts, which can realize real-time adjustment of the image by amplifying, integrating and differentiating the feedback parameters.

[0042] 5. Defocus feedback parameter, which refers to the feedback parameter for the wafer defocus height during the motion process of the motion stage. The feedback parameter is also called feedback PID value. In this application, the defocus feedback parameter can be obtained by acquiring 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 realize feedback PID control through the PID controller, which can be used to correct the deviation and compensate for the wafer defocus height of the motion stage in real time, so as to ensure the stability and accuracy of the system.

[0043] Embodiment one

[0044] For ease of understanding, the architecture of the wafer image scanning system is first described. The above wafer image scanning method can be used in the wafer image scanning system, and the above wafer image scanning system can be applied to the scanning scene of the wafer, the processing scene of the wafer, etc. Please refer to Figure 1 , Figure 1 is the architecture diagram of the wafer image scanning system provided by the embodiment of the present application. As Figure 1 shown, the above wafer image scanning system can include a motion stage 1a and a terminal device 1b. The above terminal device 1b can be used to interact with the motion stage 1a, which can be a tablet, a computer, etc. for storing and calling program code to execute the wafer image scanning method. The interaction process between the terminal device 1b and the motion stage 1a is described below.

[0045] In some possible embodiments, before scanning the wafer to be scanned, the motion stage 1a can carry a reference wafer for obtaining wafer focus calibration data, and the reference wafer can be a super flat wafer or a wafer with little or no surface fluctuation error. The terminal device 1b can control the motion stage 1a to carry the reference wafer to move based on a second motion trajectory to scan the reference wafer, where the second motion trajectory can be a motion trajectory pre-planned and set for obtaining wafer focus calibration data, including but not limited to one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygon trajectory, and a horizontal and vertical trajectory. The terminal device 1b can obtain wafer defocus heights and position information of the reference wafer at each feature point in the second motion trajectory, and determine a focus-pursuit compensation height of each feature point based on the wafer defocus height of each feature point. The terminal device can generate wafer calibration data based on the position information and the focus-pursuit compensation height of each feature point.

[0046] Optionally, in some possible embodiments, the wafer calibration data can be stored as a spatial two-dimensional focus-pursuit compensation height table, where one dimension of the spatial two-dimensional focus-pursuit compensation height table stores position information of each feature point in space, and the other dimension stores the focus-pursuit compensation height of each feature point. Therefore, if the position information of any feature point in space is determined, the focus-pursuit compensation height corresponding to the position information can be obtained based on the spatial two-dimensional focus-pursuit compensation height table. That is, the spatial two-dimensional focus-pursuit compensation height table stores the position information of each feature point and the focus-pursuit compensation height corresponding to each position information.

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

[0048] In some possible implementation manners, after the terminal device 1b acquires the wafer calibration data, the terminal device 1b can perform scanning on the to-be-scanned wafer 1c. The terminal device 1b can detect the wafer defocus height of the to-be-scanned wafer 1c carried on the motion table 1a, to obtain the reference height of the to-be-scanned wafer 1c. The terminal device 1b can further generate a first motion trajectory based on the position information of each feature point included in the wafer focusing calibration data, and then control the motion table 1a to carry the to-be-scanned wafer 1c to move based on the first motion trajectory. It can be understood that the wafer focusing calibration data includes the position information of a plurality of feature points, and the position information of the 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. The feature points are feature points on the second motion trajectory, and therefore the first motion trajectory generated based on the position information of each feature point included in the wafer focusing calibration data can be equivalent to the second motion trajectory. Here, the first motion trajectory being equivalent to the second motion trajectory includes but is not limited to that the first motion trajectory is completely the same as the second motion trajectory, or that the position deviation between the feature points on the first motion trajectory and the second motion trajectory is within an error range, which can be determined according to actual application scenarios and is not limited herein. When the motion table 1a moves to each feature point in the first motion trajectory, the terminal device 1b can obtain the focus-pursuit compensation height of each feature point based on the position information of each feature point, to perform focus-pursuit compensation on the to-be-scanned wafer 1c. For example, if the motion table 1a moves to any one of the feature points and the wafer focusing calibration data is a spatial two-dimensional focus-pursuit compensation height table, the terminal device 1b can query the focus-pursuit compensation height corresponding to the position information of the feature point from the spatial two-dimensional focus-pursuit compensation height table according to the position information of the feature point, and take the focus-pursuit compensation height as the focus-pursuit compensation height of the to-be-scanned wafer 1c moving to the feature point. If the motion table 1a moves to any one of the feature points and the wafer focusing calibration data is a spatial two-dimensional focus-pursuit compensation curve, the terminal device 1b can calculate the focus-pursuit compensation height corresponding to the position information of the feature point based on the position information of the feature point and the spatial two-dimensional focus-pursuit compensation curve, and take the focus-pursuit compensation height as the focus-pursuit compensation height of the to-be-scanned wafer 1c moving to the feature point. If the motion table 1a moves to any one of the non-feature points in the feature points, the terminal device 1b can calculate the focus-pursuit compensation height of the non-feature point according to the focus-pursuit compensation height of the feature point closest to the non-feature point.

[0049] In some possible implementation manners, the terminal device 1b can further detect the defocus feedback parameter when the to-be-scanned wafer 1c moves to each feature point during the movement of the motion table 1a in real time, and superimpose the reference height, the focus-pursuit compensation height and the defocus feedback parameter of the to-be-scanned wafer 1c, to generate a real-time focusing height. The terminal device 1b can perform focusing on the to-be-scanned wafer 1c based on the real-time focusing height, to obtain a wafer image of the to-be-scanned wafer 1c.

[0050] Optionally, in some feasible embodiments, 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 on 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 equipment 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 equipment that can acquire wafer images. This application does not limit this and takes the linear array camera as an example for explanation. The above-mentioned light source can be a laser or other equipment that can be used to provide lighting when the camera acquires the wafer image. This application does not limit this and takes the laser 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 to 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 control the image quality of the image through a processor ( Figure 1 The processor (not shown) processes data and generates control instructions based on the data processed by the processor. Optionally, the processor is integrated into a functional module, such as a central processing module in a motion controller, a central processing module in a focus controller, or a central processing module in a focus collection system, to implement the functions implemented by the processor. The specific functions can be determined according to the specific form of the product and are not limited here.

[0052] The focus controller is configured to receive focus data acquired by the focus collection system and, based on the focus data, to determine the focus compensation height for the wafer 1c to be scanned. The motion controller can receive the focus compensation height transmitted by the focus controller and, based on the focus compensation height, generate motion control instructions to control the motion stage 1a to focus on the wafer. It is understood that the focus controller can receive focus data from the focus collection system and determine the focus compensation height in real time, thereby enabling the motion controller to control the motion stage 1a in real time to focus on the wafer.

[0053] The motion table 1a can be an X / Z / Theta-axis motion table, or other motion table capable of carrying a wafer, and the present application does not limit the same. The X / Z / Theta-axis motion table is taken as an example for description. It can be understood that the motion table 1a can move on the X-axis, Z-axis and Theta-axis, corresponding to horizontal movement, vertical movement and rotation angle movement respectively. The motion table 1a can be used to carry a wafer and adjust the position of the wafer through movement. Optionally, the motion table 1a can further include a Y-axis motion table, which can carry a wafer to move longitudinally. The motion table 1a can move according to a motion trajectory determined by the terminal device 1b. The motion trajectory can be one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygon trajectory and a horizontal and vertical trajectory.

[0054] Referring to Figure 2 , Figure 2 is a schematic diagram of a spiral trajectory provided by an embodiment of the present application. As shown in Figure 2 , the spiral trajectory can be an Archimedean spiral. The spiral trajectory can include a plurality of feature points, and the motion radius corresponding to the plurality of feature points sorted from outside to inside decreases. The motion radius is the distance between a scanning feature point and the center of the circle. 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] Referring to Figure 3 , Figure 3 is a schematic diagram of a concentric circle trajectory provided by an embodiment of the present application. As shown in Figure 3 , the concentric circle trajectory can be a plurality of circle trajectories with the same center (only part of the circle trajectories are shown in Figure 3 ). The motion radius corresponding to each feature point (only part of the feature points are shown in Figure 3 ) in the same circle trajectory is the same, and the motion radius corresponding to each feature point included in the circle trajectory from outside to inside decreases by circle.

[0056] Referring to Figure 4 , Figure 4 is a schematic diagram of a polygon trajectory provided by an embodiment of the present application. As shown in Figure 4 , the polygon trajectory can be composed of a plurality of geometric trajectories (only part of the geometric trajectories are shown in Figure 4 ) concentrically circumscribed, for example, a plurality of pentagonal trajectories. A plurality of vertices in each geometric trajectory are located on the same circle, and the motion trajectory between two adjacent vertices is a straight line. The motion radius corresponding to the feature points (only part of the feature points are shown in Figure 4 ) included in each geometric trajectory from outside to inside decreases by one. That is, the motion radius corresponding to the feature points included in the geometric trajectory located on the outside is greater than the motion radius corresponding to the feature points included in the geometric trajectory located on the inside.

[0057] Referring toFigure 5 , Figure 5 is a schematic diagram of a horizontal and vertical trajectory provided by an embodiment of the present application. As shown in Figure 5 , the horizontal and vertical trajectory (i.e., a zigzag trajectory) includes multiple rows of movement trajectories (only part of the horizontal and vertical trajectory is shown in Figure 5 ). After scanning each feature point included in a row of movement trajectories (only part of the feature points are shown in Figure 5 ), the next row of movement trajectories is switched to for scanning. Each row of movement trajectories includes multiple feature points. Alternatively, the above horizontal and vertical trajectory can also include multiple columns of movement trajectories, i.e., vertical movement trajectories, which are not limited by the present application.

[0058] Referring to Figure 6 , Figure 6 is a schematic diagram of a square trajectory provided by an embodiment of the present application. As shown in Figure 6 , the square trajectory includes multiple quadrilaterals (only part of the square trajectory is shown in Figure 6 ), each of which includes multiple feature points (only part of the feature points are shown in Figure 6 ). The movement table 1a can switch the movement direction when running to the vertex of the quadrilateral, and the angle between the switched direction and the movement direction before switching is 90°.

[0059] For ease of understanding, the interaction process between the terminal device 1b and the movement table 1a is described below by taking an example of the terminal device 1b including a movement controller, a focusing controller, and an image acquisition device, wherein the image acquisition device includes a light source and a camera, and the focusing controller integrates a PID control module, which is used to perform the functions realized by the PID controller.

[0060] In some possible embodiments, the terminal device 1b can scan the wafer to be scanned 1c carried by the movement table 1a through the image acquisition device in the focusing collection system, acquire a wafer image of the wafer to be scanned 1c, and then acquire a wafer defocus height of the wafer to be scanned 1c based on the wafer image. The terminal device 1b can acquire a reference height for focusing on the wafer to be scanned 1c based on the wafer defocus height through the focusing controller. The above reference height is an initial height generated by the wafer thickness of the wafer to be scanned 1c, which can be obtained from the height of one feature point in the wafer to be scanned 1c, or from the average height of multiple feature points in the wafer to be scanned 1c, or can be recognized from the wafer image through an artificial intelligence algorithm model.

[0061] In some possible implementation manners, the terminal device 1b can generate a first motion track based on the position information of each feature point in the wafer focusing calibration data by the motion controller, and then generate a motion control instruction to control the motion stage 1a to move according to the first motion track. It can be understood that the wafer 1c to be scanned carried on the motion stage 1a is relatively static with the motion stage 1a, and can move along with the motion stage 1a according to the first motion track. When the motion stage 1a moves to any feature point, the terminal device 1b can obtain the position information of the feature point by the focusing controller, and obtain the focus compensation height corresponding to the position information based on the position information.

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

[0063] In some possible implementation manners, the terminal device 1b can obtain the focus compensation height of each feature point based on the position information of each feature point in the plurality of feature points, and obtain the focus compensation height of each non-feature point other than the plurality of feature points based on the focus compensation height of each feature point. The non-feature point is a scanning point different from the position information of the feature point planned in the first motion track, which is generated due to motion error and other factors in the actual motion process of the motion stage.

[0064] In some possible implementation manners, the terminal device 1b can calculate the superimposed height of the reference height, the focus-pursuit compensation height and the defocus feedback parameter of any feature point through the PID control module, and then can take the superimposed height as the real-time focusing height of the to-be-scanned wafer 1c moving to any feature point, and then can generate the real-time focusing height of the to-be-scanned wafer 1c moving to each feature point.

[0065] In some possible implementation manners, the terminal device 1b can obtain wafer focusing calibration data. Specifically, a reference wafer can be carried on the motion stage 1a, and the terminal device 1b controls the motion stage 1a to move based on a second motion trajectory through the motion controller to control the reference wafer to move based on the second motion trajectory. The terminal device 1b can obtain wafer images of the reference wafer moving to each feature point in the second motion trajectory through the image acquisition device, and then obtain wafer defocus heights and position information of the reference wafer moving to each feature point through the focusing controller, and determine focus-pursuit compensation heights of positions of each feature point in the second motion trajectory based on each wafer defocus height. The terminal device 1b can generate wafer focusing calibration data based on the position information and the focus-pursuit compensation heights of each feature point. The second motion trajectory can include one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygon 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 reference height, the focus-pursuit compensation height, the defocus feedback parameter, the real-time focusing height and the like can be optical path data, and operations such as superimposition and cancellation can be performed between different parameters.

[0067] The wafer image scanning system provided in the application can detect the wafer defocus height of the to-be-scanned wafer carried on the motion table to obtain the reference height for focus pursuit of the to-be-scanned wafer; the first motion trajectory is generated based on the position information of each feature point included in the wafer focusing calibration data, and the motion table is controlled to move based on the first motion trajectory to control the to-be-scanned wafer to move based on the first motion trajectory; the focus pursuit compensation height of the to-be-scanned wafer moving to each feature point is obtained based on the wafer focusing calibration data; the defocus feedback parameter when the to-be-scanned wafer moves to each feature point is obtained, the real-time focusing height of the to-be-scanned wafer moving to each feature point is generated based on the reference height, the focus pursuit compensation height and the defocus feedback parameter, and the to-be-scanned wafer is focused based on the real-time focusing height to obtain the wafer image of the to-be-scanned wafer; the motion table in the wafer image scanning system can carry the to-be-scanned wafer to move. Therefore, the wafer image scanning system can compensate the wafer defocus height in advance before scanning the to-be-scanned wafer based on the reference height and the focus pursuit compensation height of each feature point, and the real-time focusing height of the to-be-scanned wafer moving to each feature point is adjusted in real time through the real-time obtained defocus feedback parameter, so that the focusing response speed and focusing accuracy are high, and the applicability is strong.

[0068] Embodiment Two

[0069] Reference Figure 7 , Figure 7 is a flowchart of a wafer image scanning method provided in an embodiment of the application. Figure 7 The wafer image scanning method shown in the figure is applicable to Figure 1 The wafer image scanning system shown in the figure is described below with the terminal device as the execution subject for the convenience of description. As Figure 7 The wafer image scanning method described above can include the following steps:

[0070] In step S101, the wafer defocus height of the to-be-scanned wafer carried on the motion table is detected to obtain the reference height for focus pursuit of the to-be-scanned wafer.

[0071] In some feasible embodiments, the terminal device can detect the to-be-scanned wafer carried on the motion table to obtain the reference height of the to-be-scanned wafer. The terminal device can obtain the initial image of the to-be-scanned wafer carried on the motion table through the image acquisition device. The initial image can be the image of the entire wafer, or the image of one or more scanning points in the wafer. The terminal device can input the initial image into the reference height identification model or other algorithm model that can identify the reference height according to the image to identify the initial height of the wafer. Specifically, the terminal device can first identify the wafer defocus height according to the initial image, for example, determine the wafer defocus height according to the diameter of the light spot generated due to defocus in the initial image, and then obtain the reference height for focus pursuit of the to-be-scanned wafer based on the wafer defocus height.

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

[0073] In step S102, a first motion trajectory is generated based on the position information of each feature point included in the wafer focusing calibration data, and the motion table is controlled 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 possible implementation manners, the terminal device can obtain the position information of each feature point from the wafer focusing calibration data, and generate the first motion trajectory based on the distribution rule between the position information of each feature point. For example, if the position information of each feature point indicates that a plurality of feature points are located in the same row (that is, the longitudinal coordinates are the same) in the space, and the longitudinal coordinate difference between different rows increases regularly, the first motion trajectory can be generated based on the position information of each feature point in the wafer focusing calibration data as a horizontal and vertical trajectory (that is, a zigzag trajectory). If the position information of each feature point indicates that a plurality of feature points are located in the same row (that is, the longitudinal coordinates are the same) in the space, and the longitudinal coordinate difference between different rows increases regularly, and the horizontal coordinate difference between the plurality of feature points in the same row is the same, the first motion trajectory can be generated based on the position information of each feature point in the wafer focusing calibration data as a square trajectory. If the position information of each feature point indicates that a plurality of feature points are located on the same circle, and the centers of different circles are the same, the first motion trajectory can be generated based on the position information of each feature point in the wafer focusing calibration data as a concentric circle trajectory. If the position information of each feature point indicates that a plurality of feature points are located on the same circle, and the centers of different circles are the same, and the distance between the adjacent two feature points in the plurality of feature points on the same circle is equal, the first motion trajectory can be generated based on the position information of each feature point in the wafer focusing calibration data as a polygon trajectory. If the position information of each feature point indicates that a plurality of feature points are located on a spiral line, the first motion trajectory can be generated based on the position information of each feature point in the wafer focusing calibration data as a spiral trajectory. It should be noted that if the position information of the plurality of feature points indicates a plurality of possible motion trajectories, the specific first motion trajectory should be determined according to the actual product form or according to the pre-set rule, which is not limited in this application.

[0075] In some possible implementation manners, after the terminal device generates the first motion trajectory, the terminal device can control the motion table to move based on the first motion trajectory, so as to drive the wafer to be scanned carried on the motion table to move based on the first motion trajectory.

[0076] In step S103, the wafer focusing calibration data is used to obtain the focus-pursuit compensation height of the wafer to be scanned when moving to each scanning point. The scanning points include the feature points and the non-feature points other than the feature points.

[0077] In some possible implementation manners, the terminal device can obtain the focus-pursuit compensation height of the wafer to be scanned when moving to each scanning point based on the wafer focusing calibration data. Specifically, when the terminal device controls the motion table to move based on the first motion trajectory, the position information of the motion table can be obtained in real time, that is, the position information of the wafer to be scanned is obtained in real time. When the position information of the wafer to be scanned is the same as the position information of the feature points, it indicates that the wafer to be scanned has moved to the scanning point.

[0078] In some possible implementation manners, the terminal device can acquire the focus-pursuit compensation height based on wafer focus calibration data according to position information of the scanning points indicated by the wafer to be scanned. The storage form of the wafer focus calibration data can be a spatial two-dimensional focus-pursuit compensation height table, a spatial two-dimensional focus-pursuit compensation curve, or other forms that can store position information and focus-pursuit compensation height corresponding to the position information, and the present application does not limit this.

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

[0080] In step S104, the defocus feedback parameter when the wafer to be scanned moves to each of the scanning points is acquired, the real-time focus height when the wafer to be scanned moves to each of the scanning points is generated based on the reference height, the focus-pursuit compensation height, and the defocus feedback parameter, and the wafer to be scanned is focused based on the real-time focus height to obtain a wafer image of the wafer to be scanned.

[0081] In some possible implementation manners, the terminal device can also detect the wafer image acquired when the wafer to be scanned moves to each of the scanning points, and identify the defocus feedback parameter based on historical data of the wafer image. The terminal device can generate the real-time focus height when the wafer to be scanned moves to each of the scanning points based on the reference height, the focus-pursuit compensation height, and the 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 a 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 last feature point, and take the wafer defocus height of the last wafer image as the defocus feedback parameter of the current feature point. That is, the defocus feedback parameter is obtained according to the historical data of scanning the wafer to be scanned, which can be obtained according to the historical data of the last wafer image, or obtained according to the historical data of a plurality of wafer images scanned before the current feature point, and the present application does not limit this. If the current feature point is the first feature point to be scanned, that is, no other feature points are scanned before the current feature point, the historical data of the wafer defocus height is empty, and the defocus feedback parameter of the current feature point can be empty. For example, if the implementation focus height of the motion stage is obtained by superposition when the defocus feedback parameter is empty, the defocus feedback parameter can be set to "0".

[0083] By using the wafer image scanning method provided in the present application, the reference height for focus pursuit of the wafer to be scanned is obtained, the first motion trajectory is generated based on the position information of each feature point included in the wafer focus calibration data to control the wafer to be scanned to move based on the first motion trajectory; the focus pursuit compensation height of the wafer to be scanned moving to each feature point is obtained based on the wafer focus calibration data; the defocus feedback parameter when the wafer to be scanned moves to each feature point is obtained, and the wafer to be scanned is focused based on the real-time focus height generated by the reference height, the focus pursuit compensation height and the defocus feedback parameter 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 focus pursuit compensation height of each feature point, and the real-time focus height when the wafer to be scanned moves to each feature point is adjusted in real time through the real-time obtained defocus feedback parameter, so that the focus response speed and focus accuracy are high, and the applicability is strong.

[0084] Embodiment three

[0085] Referring to Figure 8 , Figure 8 is another flowchart of the wafer image scanning method provided by the embodiments of the present application. Figure 8 The wafer image scanning method shown in Figure 1 The wafer image scanning system shown in, in order to facilitate the description, the embodiments of the present application are described with the terminal device as the execution subject. As Figure 8 The wafer image scanning method described above can include the following steps:

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

[0087] In some possible implementation manners, the terminal device can pre-plan and set the second motion track according to actual product morphology or application requirements, and then control the reference wafer carried on the motion table to move based on the second motion track. The reference wafer can be an ultra-flat wafer, the surface of the ultra-flat wafer has high flatness, and fluctuation errors of the wafer surface caused by assembly errors of the motion table, machining errors of parts and the like can be avoided, and the accuracy of the detection result can be improved. The second motion track includes one of a spiral track, a concentric circle track, a square track, a polygon track and a horizontal and vertical track, or can be another type of motion track, which is not limited in the present application.

[0088] For ease of understanding, the description of the second motion track can be jointly referred to the description of the spiral track, the concentric circle track, the square track, the polygon track and the horizontal and vertical track in the above embodiments, and will not be repeated here.

[0089] In step S20, wafer defocusing heights and position information of the reference wafer moving to each feature point in the second motion track are obtained, and a focus-pursuit compensation height of each feature point in the second motion track is determined based on the wafer defocusing height of each feature point.

[0090] In some feasible embodiments, 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 due to 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 embodiments, the terminal device can generate a focus compensation height based on 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 size. "+" can be used to indicate the upper direction and "-" to indicate the lower direction, or "+" can be used to indicate the lower direction and "-" to indicate the upper direction. This 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, the indicator motion stage should move upward 0.1cm to achieve the focus of the wafer to be scanned at the feature point. The terminal device can follow the movement of the motion 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] In step S301 , 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.

[0092] Optionally, in some feasible implementations, after obtaining the position information of each feature point and the focus compensation height corresponding to the position information, the terminal device may generate a spatial two-dimensional focus compensation height table based on the position information and focus compensation height. The spatial two-dimensional focus compensation height table includes one dimension for storing the position information of each feature point, and another dimension for recording the focus compensation height of each feature point. The two-dimensional focus compensation height table stores the position information and focus compensation height corresponding to the second motion trajectory.

[0093] Take the second motion trajectory as an example, see Figure 9 , Figure 9 This is a schematic representation of the spatial two-dimensional focus compensation height provided by the embodiment of the present application. Figure 9 As shown, the spatial two-dimensional focus compensation altimeter records each feature point through horizontal and vertical tracks ( Figure 9Only one feature point is displayed in the image), the horizontal and vertical tracks ( Figure 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. Figure 9 The spatial two-dimensional focus compensation height table shown also includes the focus compensation height of the feature points. Figure 9 The focus compensation height can be represented by "H" in the image. The direction can be indicated by "+" or "-." For example, "+" indicates upward, and "-" indicates downward. For example, if the focus compensation height is stored as +0.1cm, this indicates that the motion stage should move upward 0.1cm to perform the focus 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. Different motion trajectories generate different spatial two-dimensional focus compensation height tables, meaning that 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 may then generate an estimated focus compensation height at each feature point position before scanning the wafer to be scanned.

[0095] In step S302 , 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.

[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 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 and cosine equation, an exponential equation, etc., and this application does not impose any restrictions on this.

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

[0098] In step S40, the wafer defocus height of the wafer to be scanned carried on the motion table is detected to obtain the reference height for focus tracking of the wafer to be scanned.

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

[0100] In step S50, a first motion trajectory is generated based on the position information of each feature point included in the wafer focus calibration data, and the motion table is controlled 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 possible implementations, the terminal device can acquire the position information of each feature point from the wafer focus calibration data, determine the type of the second motion trajectory used when generating the wafer focus calibration data based on the position information, and then generate the first motion trajectory. Wherein, the first motion trajectory can be one of a spiral trajectory, a concentric circle trajectory, a square trajectory, a polygon 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 of step S50 can be referred to the description of step S102, which will not be repeated here.

[0102] In step S60, the focus compensation height of the wafer to be scanned when moving to each scanning point is acquired based on the wafer focus calibration data.

[0103] In some possible implementation manners, the terminal device can acquire, based on the position information, a focus-pursuing compensation height of the wafer to be scanned moving to each scanning point according to the wafer focus calibration data. Each scanning point includes each feature point and a plurality of non-feature points other than the feature points. The terminal device can first acquire the focus-pursuing compensation height of each feature point, and then determine the focus-pursuing compensation height of each non-feature point by using an interpolation algorithm or the like. Specifically, the terminal device can acquire the position information of the wafer to be scanned in real time during the movement of the wafer to be scanned, and 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-pursuing compensation height can be acquired according to the position information of the feature point. Optionally, the terminal device can also acquire the focus-pursuing 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 movement sequence of the first movement track can be acquired from the wafer focus calibration data, and the focus-pursuing compensation height of the next feature point can be acquired based on the position information of the next feature point, so that the wafer defocus height can be compensated for by the movement table before the next feature point is focused, to realize fast focusing.

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

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

[0106] In some possible implementation manners, the terminal device can determine the focus-pursuing compensation height of the non-feature point by using an interpolation calculation method such as one-time linear interpolation, multiple times of spline curve interpolation, or sine and cosine interpolation. The terminal device can obtain target position information of a target feature point closest to the non-feature point based on the position information of the non-feature point, and then can obtain the target focus-pursuing compensation height of the target feature point according to the target position information of the target feature point. For example, if the first motion track includes one non-feature point and two feature points, 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), 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 closest feature point to the non-feature point in the first motion track, and therefore the terminal device can determine the first feature point as the target feature point. Further, the terminal device can calculate the focus-pursuing compensation height corresponding to the position information of the non-feature point according to the interpolation calculation method such as one-time linear interpolation, multiple times of spline curve interpolation, or sine and cosine interpolation, to adjust the height of the motion table based on the focus-pursuing compensation height of the non-feature point, so that the motion of the motion table is smooth and the height for focusing on the wafer at the feature point can be quickly reached at the feature point. For ease of understanding, the implementation manner of the step S60 can be jointly referred to the description of the step S103, and details are not described herein again.

[0107] In step S70, the defocus feedback parameter when the wafer to be scanned moves to each scanning point is obtained, the real-time focusing height when the wafer to be scanned moves to each scanning point is generated based on the reference height, the focus-pursuing compensation height, and the defocus feedback parameter, 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.

[0108] In some possible implementation manners, the terminal device can obtain the defocus feedback parameter when the wafer to be scanned moves to each scanning point in real time, and then generate the real-time focusing height. Referring to FIG. 7, Figure 10 Figure 10 FIG. 7 is a schematic diagram of a generation process of the real-time focusing height provided by the embodiments of the present application. The terminal device can detect the position information and the defocus feedback parameter (i.e., the defocus feedback parameter) of the motion table in real time during the motion of the motion table, to compensate for the focusing error in the motion process of the motion table based on the defocus feedback parameter. As shown in FIG. 7, Figure 10 The terminal device can calculate the superimposed height of the reference height, the focus-pursuing compensation height, and the defocus feedback parameter of the wafer to be scanned at any scanning point, and determine the superimposed height as the real-time focusing height when the wafer to be scanned moves to any scanning point, to generate the real-time focusing height when the wafer to be scanned moves to each scanning point. ​

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

[0110] Step S80: Determine whether the wafer scanning is completed.

[0111] In some possible implementations, the terminal device can determine whether the wafer scanning is completed. For example, the terminal device can determine based on the scanning situation of each scanning point in the first motion trajectory. If the terminal device detects that each scanning point included in the first motion trajectory is scanned, it is determined that the wafer scanning is completed, and step S90 is performed; if the terminal device detects that there is a scanning point in the first motion trajectory that is not scanned, it is determined that the wafer scanning is not completed, and step S60 is performed.

[0112] Step S90: Obtain a wafer image.

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

[0114] By using the wafer image scanning method provided in this application, the wafer defocusing height of the wafer to be scanned carried on the motion platform can be detected to obtain a reference height for focusing on the wafer to be scanned; a first motion trajectory is generated based on the position information of each feature point included in the wafer focusing calibration data, and the motion platform is controlled to move based on the first motion trajectory to control the wafer to be scanned to move based on the first motion trajectory; the focusing compensation height of the wafer to be scanned when moving to each scanning point is obtained based on the wafer focusing calibration data; the defocusing feedback parameter when the wafer to be scanned moves to each scanning point is obtained, the real-time focusing height when the wafer to be scanned moves to each scanning point is generated based on the reference height, the focusing compensation height, and the defocusing feedback parameter, 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. Therefore, the wafer defocusing height can be compensated in advance before the wafer to be scanned is scanned based on the reference height and the focusing 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 through the real-time obtained defocusing feedback parameter, so that the focusing response speed and focusing accuracy are high, and the applicability is strong.

[0115] Embodiment Four

[0116] Please refer to Figure 11 , Figure 11 is a structural schematic diagram of a wafer image scanning device provided in an embodiment of the application. As shown inFigure 11 The wafer image scanning device 10 shown can 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 can also be a computer program, for example, the computer program is an application software. The device can be used to execute the corresponding steps in the wafer image scanning method provided in the embodiment of the present application. Figure 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, which is 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 is 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 along the first motion trajectory to control the wafer to be scanned to move along the first motion trajectory;

[0119] An acquisition module 103 is configured to acquire, based on the wafer focus calibration data, a focus compensation height of the wafer to be scanned when the wafer moves to each scanning point, 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 above-mentioned wafer to be scanned moves to the above-mentioned each scanning point, generate the real-time focusing height when the above-mentioned wafer to be scanned moves to the above-mentioned each scanning point based on the above-mentioned reference height, the above-mentioned focus compensation height and the above-mentioned defocus feedback parameters, and focus the above-mentioned wafer to be scanned based on the above-mentioned real-time focusing height to obtain the wafer image of the above-mentioned wafer to be scanned.

[0121] The specific functions implemented by the detection module 101 can be found in the Figure 7 Alternatively, you can refer to step S101 in the corresponding embodiment. 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 In the embodiment shown, step S102, or alternatively, may 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, step S103, or, alternatively, see the 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, step S104, or alternatively, see the aboveFigure 8 Step S70 in the illustrated embodiment is not described in detail.

[0122] Example 5

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

[0124] In such Figure 12 In the terminal device 100 shown, the network interface 1004 can provide network communication functions; 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 aforementionedFigures 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 embodiments of the present application can perform the foregoing Figures 7 to 10 The wafer image scanning method of the illustrated embodiment will not be described again. In addition, the beneficial effects of using the same method will not be described again.

[0126] In addition, it should be noted that the embodiments of the present application also provide a computer readable storage medium, and the aforementioned computer readable storage medium stores the computer program executed by the wafer image scanning method mentioned above, and the aforementioned computer program includes program instructions, and when the aforementioned processor executes the aforementioned program instructions, the aforementioned terminal device can execute the foregoing Figures 7 to 10 The aforementioned wafer image scanning method provided by the illustrated embodiment will not be described again. In addition, the beneficial effects of using the same method will not be described again. For technical details of the computer readable storage medium embodiments involved in the present application, please refer to the description of the method embodiments of the present application.

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

[0128] In addition, it should be noted that the embodiments of the present application also provide a computer program product or a computer program, which includes computer instructions 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 foregoing Figures 7 to 10 The method provided by the illustrated embodiment.

[0129] Those of ordinary skill in the art will realize that the systems and algorithms described in connection with the embodiments disclosed herein can be embodied in electronic hardware, computer software, or both. The disclosure is not intended to be limited to one technology or illustrative language. The use of the terms "example" and "exemplary" is intended to present concepts in a concrete form. The functions described can be implemented in hardware, software, or combinations thereof. However, such an implementation is merely one example and other implementations are possible. Specifically, different examples of circuits and systems can be constructed to implement the described functions and aspects. These are merely a few examples of systems that can be employed to implement functionality described herein. Accordingly, it is submitted that one of ordinary skill in the art will recognize the interchangeability of various hardware and software implementations, and it is intended that the scope of the disclosure should encompass all such variations.

Claims

1. A wafer image scanning method, characterized in that: include: Detecting a wafer defocus height of a wafer to be scanned, which is carried on a moving stage, to obtain a reference height for tracking focus on the wafer to be scanned; 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; Obtaining, from the wafer focus calibration data, a focus compensation height when the wafer to be scanned moves to each of the feature points, and obtaining a focus compensation height when the wafer to be scanned moves to a non-feature point based on the focus compensation height of each of the feature points, so as to obtain a focus compensation height when the wafer to be scanned moves to each of the scanning points, wherein each of the scanning points includes each of the feature points and the non-feature points other than the feature points; Obtain the defocus feedback parameters of the wafer to be scanned when it moves to the various scanning points, generate the real-time focus height of the wafer to be scanned when it moves to the various scanning points 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 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 a 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, determining a target feature point closest to the non-feature point 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.

3. The method according to any one of claims 1-2, characterized in that The generating of 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 includes: 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.

4. The method according to any one of claims 1 to 2, 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 a reference wafer carried on the motion stage to move based on the second motion trajectory, obtaining wafer defocus height and position information of the reference wafer moving to each feature point in the second motion trajectory, and determining a focus compensation height for each feature point in the second motion trajectory based on the wafer defocus height of each feature point; generating wafer focus calibration data based on the position information of each feature point and the focus compensation height; 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.

5. The method according to claim 4, characterized in that Generating wafer focus calibration data based on the position information of each feature point and the focus 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.

6. The method according to claim 4, characterized in that Generating wafer focus calibration data based on the position information of each feature point and the focus 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.

7. The method according to claim 6, 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.

8. A wafer image scanning device, characterized in that: include: A detection module is used to detect the wafer defocus height of the wafer to be scanned, which is carried on the moving stage, to obtain a reference height for tracking the 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, from the wafer focus calibration data, a focus compensation height when the wafer to be scanned moves to each of the feature points, and acquire, based on the focus compensation heights of each of the feature points, a focus compensation height when the wafer to be scanned moves to a non-feature point, so as to acquire a focus compensation height when the wafer to be scanned moves to each scanning point, wherein each scanning point includes each of the feature points and the non-feature points other than the feature points; A focusing module is used to obtain the defocus feedback parameters when the wafer to be scanned moves to the various scanning points, generate the real-time focus height when the wafer to be scanned moves to the various scanning points 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.

9. 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 code, and the processor is used to call the program code to execute the method according to any one of claims 1 to 7.

10. A wafer image acquisition system, characterized in that: include: A moving table and a terminal device as claimed in claim 9; wherein the moving table is used to carry wafers.

11. 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 7.

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