Wafer scanning method and device and storage medium

Abstract

The invention discloses a wafer scanning method and device and a storage medium. The method comprises the steps of obtaining the radius of a to-be-scanned wafer and the preset effective length of a linear light spot of a scanning camera; the wafer is divided into a first area and a second area based on the radius and the effective length of the linear light spot, the first area comprises an annular area with the radius value larger than a first preset radius threshold value, and the second area comprises a circular area with the radius value smaller than the first preset radius threshold value; controlling the scanning camera to perform spiral line scanning on the first area, and then performing back-and-forth scanning on the second area along a straight line until scanning is completed; according to the invention, the surface area of the wafer is divided into the annular first area and the circular second area, the first area is subjected to spiral line scanning to improve the scanning rate of the wafer, and then the second area is subjected to back-and-forth scanning to ensure that the position close to the center of the wafer is accurately scanned.

Description

Technical Field

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

[0002] Integrated circuit front-end wafer process control defect detection is usually performed by a combination of optical full inspection and electron beam spot checks. The process tact of the full inspection determines the output of the entire Fab wafer. With the popularization of modern electronic devices and the promotion of AI, there is a periodic explosion of demand for chips, memory, etc. Improving the production tact of each process link of a single production line in a Fab with limited production expansion has become an urgent need for the Fab. With the same cost investment in detection equipment, improving the wafer defect detection tact in the front-end full inspection can increase the production capacity of the entire Fab.

[0003] At present, the main method of wafer scanning is concentric circle scanning. To completely scan the entire wafer surface, the concentric circle scanning method requires scanning 40 to 50 circles. During each circle of scanning, it is necessary to control the rotation axis of the motion platform to stop rotating and switch the concentric circle scanning radius. Then, the rotation axis of the motion platform needs to be accelerated to the specified acceleration before the next circle of scanning can be performed. The process of switching the scanning radius and accelerating the rotation axis consumes a lot of time, which seriously affects the efficiency of wafer scanning. Summary of the Invention

[0004] In view of this, the present application provides a wafer scanning method, device and storage medium to solve the problem of low efficiency of existing wafer scanning.

[0005] In order to solve the above technical problems, a technical solution adopted in this application is: providing a wafer scanning method, which includes: obtaining the radius of the wafer to be scanned and the pre-set effective length of the line spot of the scanning camera; dividing the wafer into a first area and a second area based on the radius and the effective length of the line spot, the first area includes an annular area with a radius value greater than a first preset radius threshold, and the second area includes a circular area with a radius value less than the first preset radius threshold; controlling the scanning camera to perform a spiral scan on the first area, and then scan the second area back and forth along a straight line until the scanning is completed.

[0006] As a further improvement of the present application, the scanning camera is controlled to perform a spiral scan on the first area, including: dividing the first area into a first sub-area whose radius value is greater than a second preset radius threshold and a second sub-area whose radius value is between the first preset radius threshold and the second preset radius threshold, and the second preset radius threshold is greater than the first preset radius threshold; controlling the scanning camera to perform concentric circle scanning on the first sub-area and then perform a spiral scan on the second sub-area.

[0007] As a further improvement of the present application, the scanning camera is controlled to perform concentric circle scanning on the first sub-area, including: moving the rotating axis to the first sub-area according to the effective length of the linear spot and the starting and ending radii of the first sub-area; controlling the rotating axis to start accelerating and rotate at a uniform speed after accelerating to a first preset linear speed, and collecting a circle of image data at a frame rate during the uniform rotation stage, and recording the serial number of each frame of image data, and at the same time recording the first starting position of the first frame of image data collected by the concentric circle scanning.

[0008] As a further improvement of the present application, after recording the serial number of each frame of image data, it also includes: when there is a defect in the target image data, confirming the first row and column position information of the defect in the target image data; combining the first row and column position information and the first starting position to calculate the polar coordinates of the defect in the wafer coordinate system; and using the polar coordinates and the shooting angle of the scanning camera to calculate the Cartesian coordinates of the defect.

[0009] As a further improvement of the present application, a spiral line scan is performed on the second sub-area, including: moving the rotating axis to a specified starting radius position according to the effective length of the line spot and the starting and ending radii of the second sub-area; controlling the rotating axis to start accelerating and accelerate to a second preset linear speed, and then controlling the radius and angle of the rotating axis to perform spiral motion in the mode of an Archimedean spiral based on the step length set according to the effective length of the line spot, and collecting image data at a frame rate during the spiral motion stage, and recording the serial number of each frame of image data, and at the same time recording the second starting position of the first frame of image data collected by the spiral line scan until the second sub-area is completely scanned.

[0010] As a further improvement of the present application, after completely scanning the second sub-area, it also includes: when there is a defect in the target image data, confirming the second row and column position information of the defect in the target image data; combining the second row and column position information, the second starting position, the radius and pitch of the Archimedean spiral to calculate the polar coordinates of the defect in the wafer coordinate system; and using the polar coordinates and the shooting angle of the scanning camera to calculate the Cartesian coordinates of the defect.

[0011] As a further improvement of the present application, the second area is scanned back and forth along a straight line, including: fixing the rotation axis and moving the translation axis to a third starting position; obtaining the center position of the wafer, and confirming the scanning direction based on the third starting position and the center position; controlling the translation axis to perform a straight line scan along the scanning direction, and after completing a line of scanning, controlling the translation axis to move a preset step length perpendicular to the scanning direction, and then performing a straight line scan in the direction opposite to the scanning direction, and repeating the above scanning process until the second area is completely scanned.

[0012] As a further improvement of the present application, after completely scanning the second area, it also includes: when there is a defect in the target image data, confirming the third row and column position information of the defect in the target image data; calculating the Cartesian coordinates of the defect based on the third starting position, the third row and column position information, and the shooting angle of the scanning camera.

[0013] In order to solve the above technical problems, another technical solution adopted in this application is: to provide a wafer scanning device, which includes: an acquisition module, used to obtain the radius of the wafer to be scanned and the preset effective length of the line spot of the scanning camera; a division module, used to divide the wafer into a first area and a second area based on the radius and the effective length of the line spot, the first area includes an annular area with a radius value greater than a first preset radius threshold, and the second area includes a circular area with a radius value less than the first preset radius threshold; a scanning module, used to control the scanning camera to perform a spiral scan on the first area, and then scan the second area back and forth along a straight line until the scan is completed.

[0014] In order to solve the above technical problems, another technical solution adopted in this application is: to provide a computer device, which includes a processor and a memory coupled to the processor, wherein program instructions are stored in the memory, and when the program instructions are executed by the processor, the processor executes the steps of the wafer scanning method as described in any one of the above items.

[0015] In order to solve the above technical problems, another technical solution adopted in the present application is: providing a storage medium storing program instructions capable of implementing any of the above wafer scanning methods.

[0016] The beneficial effects of the present application are as follows: the wafer scanning method of the present application divides the wafer surface into an annular first area occupying most of the wafer surface area and a circular second area including the center area of ​​the wafer. The annular first area is scanned by a spiral scanning method, which only requires one acceleration and deceleration process of the rotating axis, greatly reducing the time consumption caused by the repeated acceleration and deceleration process of the rotating axis, thereby greatly improving the scanning efficiency of the first area. For the center area of ​​the wafer, a straight line back and forth scanning method is adopted, which on the one hand can realize a complete scan of the center area, and on the other hand avoids the problem of reduced accuracy caused by spiral scanning when the scanning radius is too small, thereby ensuring the scanning accuracy. And after the scanning is completed, for the area with defects, the present application can also use different coordinate reconstruction methods to reconstruct the coordinates according to different scanning methods, thereby improving the scanning coordinate accuracy and helping users to quickly locate the position of the defective area on the wafer surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a flow chart of a wafer scanning method according to an embodiment of the present invention;

[0018] Figure 2 1 is a schematic diagram of a wafer scanning method according to an embodiment of the present invention, wherein the wafer is scanned back and forth along a straight line;

[0019] Figure 3 1 is a schematic diagram of the functional modules of a wafer scanning device according to an embodiment of the present invention;

[0020] Figure 4 is a schematic structural diagram of a computer device according to an embodiment of the present invention;

[0021] Figure 5 It is a schematic structural diagram of a storage medium according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0023] The terms "first," "second," and "third" in this application are used only for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of such features. In the description of this application, "multiple" means at least two, for example, two, three, etc., unless otherwise specifically defined. All directional indications in the embodiments of this application (such as up, down, left, right, front, back...) are only used to explain the relative positional relationship, movement, etc. between the components under a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications also change accordingly. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products, or devices.

[0024] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] Figure 1 FIG is a flow chart of a wafer scanning method according to an embodiment of the present invention. It should be noted that the method of the present invention is not limited to the method of FIG. Figure 1 The process sequence shown is limited. Figure 1 As shown, the wafer scanning method includes the steps of:

[0026] Step S1: Obtain the radius of the wafer to be scanned and the preset effective length of the line spot of the scanning camera.

[0027] Step S2: Divide the wafer into a first area and a second area based on the radius and the effective length of the line spot, the first area includes an annular area with a radius value greater than a first preset radius threshold, and the second area includes a circular area with a radius value less than the first preset radius threshold.

[0028] It should be noted that the first preset radius threshold is pre-set. Specifically, when scanning the wafer surface using a spiral scanning method, the scanning camera is controlled to scan from the edge of the wafer and gradually reduce the spiral scanning radius until the center of the wafer is scanned. However, as the radius decreases, continuing to use spiral scanning will lead to a decrease in efficiency due to the dense number of turns. Moreover, in the inner spiral scanning, to maintain the same linear velocity as the outer spiral, the angular velocity of the inner spiral scanning will be correspondingly reduced. When it is less than a certain value, the coordinate accuracy will also deteriorate due to hardware issues of the motion platform. Therefore, to improve scanning efficiency and scanning accuracy, this embodiment divides the wafer surface area into a first area and a second area. The first area and the second area are separated by a circle formed by using the first preset radius threshold as the radius and the wafer center as the center. The wafer surface area is divided into an annular first area and a circular second area. The annular first area occupies the majority of the wafer surface area and can be quickly scanned using the spiral scanning method. For the second area in the center of the wafer, other scanning methods can be used to avoid scanning errors caused by the spiral scanning method.

[0029] Step S3: Control the scanning camera to perform a spiral scan on the first area, and then scan the second area back and forth along a straight line until the scan is completed.

[0030] Specifically, after the surface area of ​​the wafer is divided into a first area and a second area, the scanning camera is first controlled to perform a spiral scan on the first area, and then the second area is scanned back and forth along a straight line. Among them, the first area occupies the largest surface area of ​​the wafer (about 75% to 85%). When scanning by spiral scanning, only one acceleration and deceleration is required, and the rotation axis and the translation axis move continuously and synchronously. Compared with the traditional concentric circle scanning method, the time loss of multiple starts and stops of the concentric circle scanning is avoided. For example, for a 150mm wafer, 40 to 50 spiral scans can save about 40% of the time. Therefore, this embodiment uses a spiral scanning method to scan the first area. Scanning back and forth along a straight line is a serpentine scanning method or a bow-shaped scanning method. It fills the second area through a reciprocating straight line path. It does not require the participation of the rotation axis, but only requires the movement of the translation axis. It can quickly and efficiently complete the scanning of the center area of ​​the wafer, and further reduces the hardware burden.

[0031] Furthermore, it should be understood that the wafer edge region (e.g., the outer 10-15 mm) generally requires high-precision coverage, and concentric circle scanning has strong single-circle coverage in this region, and the adaptability of the spot length and radius is high, which can quickly complete the outer circle reference data acquisition. Therefore, in order to improve the integrity and accuracy of wafer scanning, based on the above embodiment, in other embodiments, in step S3, the step of controlling the scanning camera to perform a spiral line scan on the first region specifically includes:

[0032] 1. Divide the first area into a first sub-area whose radius value is greater than a second preset radius threshold and a second sub-area whose radius value is between the first preset radius threshold and the second preset radius threshold, and the second preset radius threshold is greater than the first preset radius threshold.

[0033] 2. Control the scanning camera to perform concentric circle scanning on the first sub-area and then perform spiral scanning on the second sub-area.

[0034] Specifically, in this embodiment, the second preset radius threshold can be pre-set based on the effective length of the line spot. For example, the second preset radius threshold = wafer radius - effective length of the line spot + preset compensation value. The setting of the second preset radius threshold ensures that, under the effective length of the line spot, only one concentric circle scan of the first sub-area is required to completely cover the entire first sub-area, so that scanning the first sub-area only requires one acceleration and deceleration process of the rotation axis. The preset compensation value also prevents irregular wafer edges from being incompletely covered. Among them, the first preset radius threshold can also be set based on the effective length of the line spot, for example, the first preset radius threshold = N * effective length of the line spot, where N can be set to 2, 3, 4, etc. By dividing the first area into a first sub-area covering the wafer edge and a second sub-area between the first preset radius threshold and the second preset radius threshold, the first sub-area is scanned using a concentric circle scan method, thereby ensuring that the edge area of ​​the wafer can be completely covered. By setting the second preset radius threshold based on the effective length of the line spot, only one concentric circle scan is required, which does not increase the scanning time excessively and has a low impact on scanning efficiency.

[0035] Furthermore, the step of controlling the scanning camera to perform concentric circle scanning on the first sub-area specifically includes:

[0036] 2.1. Move the rotation axis to the first sub-area according to the effective length of the line spot and the start and end radii of the first sub-area.

[0037] Specifically, before performing concentric circle scanning, the row resolution and column resolution are calculated based on the effective length of the line spot, the start and end radii of the first sub-area, the linear velocity, and the acquisition frame rate.

[0038] The row resolution refers to the actual physical distance corresponding to each pixel or each row scan in the radial direction (row direction). h If the value is 3mm / line, it means that the radial distance increases or decreases by 3mm for each line movement (or each scan). The line resolution is determined by the effective length of the line spot (such as 3mm), ensuring seamless connection between adjacent scan lines. Combining the scan step length (d) and the spot coverage range, the formula is:

[0039]

[0040] For example, if the line spot covers 3mm and each scan is divided into 100 lines, then sp h = 0.03mm / row. In the polar coordinate system, the row resolution sp h The row number (r) in the image data can be converted into the actual radial coordinate of the wafer (r = r0 + r·sp h , where r0 represents the initial row number).

[0041] The column resolution indicates the actual angle change corresponding to each pixel or column scan in the angular direction (column direction). For example, if the column resolution sp w If the angle is 0.01 radians per column, it means that the angle increases by 0.01 radians for each column scan. The column-wise resolution is determined by the linear velocity, frame rate, and scanning circumference:

[0042]

[0043] For example, if the linear velocity is 10 mm / s, the frame rate is 1000 Hz, and the scanning radius is 150 mm, then sp w ≈0.00067 radians / column. In polar coordinates, the column resolution sp w Convert the column number (c) in the image to the actual angular coordinate of the wafer (θ=θ0+(c·sp w ) / W, where W is the image width). It should be noted that the line spot used in this embodiment is a column-oriented line spot. Therefore, the column-oriented resolution in this embodiment is the length of the line spot corresponding to a unit pixel of the image. It should be understood that, given that the camera shooting angle will produce a small angle deviation, therefore, in this embodiment, the column-oriented resolution deviation needs to be compensated.

[0044] 2.2. Control the rotating axis to start accelerating and accelerate to the first preset linear velocity, then rotate at a constant speed. During the constant rotation stage, collect a circle of image data at the frame rate, record the serial number of each frame of image data, and record the first starting position of the first frame of image data collected by concentric circle scanning.

[0045] Specifically, after accelerating the rotating shaft to a first preset linear velocity, the rotating shaft is controlled to rotate at a uniform speed according to the first preset linear velocity, and then the scanning camera is controlled to acquire images, and when acquiring the first frame of image data, the position of the first frame of image data on the wafer is recorded, and this position is recorded as the first starting position.

[0046] Furthermore, when there are defects in the image data, the method of confirming the two-dimensional coordinates of the defects is different for different scanning methods. Therefore, after recording the serial number of each frame of image data, it also includes:

[0047] 2.3. When there is a defect in the target image data, confirm the first row and column position information of the defect in the target image data.

[0048] Specifically, the first row and column position information can be confirmed according to the row resolution and the column resolution, and is recorded as (r, c).

[0049] 2.4. Combine the first row and column position information and the first starting position to calculate the polar coordinates of the defect in the wafer coordinate system.

[0050] Specifically, the polar coordinates (R ol ,θ ol ) is calculated as:

[0051]

[0052] R ol =R0;

[0053] Among them, (R0,θ0) is the coordinate of the first starting position, sp h is the row resolution, and r is the row number where the defect is located.

[0054] 2.5. Calculate the Cartesian coordinates of the defect using polar coordinates and the shooting angle of the scanning camera.

[0055] Specifically, the Cartesian coordinates (x, y) of the defect are calculated as follows:

[0056] R s =(Wc)*sp w ;

[0057] x=R ol cos(θ ol )-R s cos(θ ol -θ c );

[0058] y=R ol sin(θ ol )-R s sin(θ ol -θ c );

[0059] Among them, sp w is the column-wise resolution, c is the number of columns where the defect is located, W is the image width, θ c is the angle between the scanning camera and the scanning direction.

[0060] Furthermore, the step of performing a spiral line scan on the second sub-area specifically includes:

[0061] 2.6. Move the rotation axis to the specified starting radius position according to the effective length of the line spot and the starting and ending radii of the second sub-area.

[0062] It should be noted that in order to ensure that the second sub-area can be completely scanned, the specified starting radius should be slightly larger than the second preset radius threshold, that is, the initial position of the spiral scan starts from a certain position within the first sub-area. Therefore, when performing the first circle of spiral scanning, it is ensured that the junction between the first sub-area and the second sub-area can still be completely scanned when the pitch changes, thereby ensuring the integrity of the scanning results.

[0063] 2.7. After the rotating axis is controlled to start accelerating and accelerate to a second preset linear velocity, the radius and angle of the rotating axis are controlled to perform spiral motion in the pattern of an Archimedean spiral based on the step length set based on the effective length of the linear spot. During the spiral motion stage, image data is collected at a frame rate, and the serial number of each frame of image data is recorded. At the same time, the second starting position of the first frame of image data collected by the spiral line scan is recorded until the second sub-area is completely scanned.

[0064] It should be noted that the Archimedean spiral can be expressed as: r=a+bθ, where r represents the radius, θ represents the polar angle (radians, usually starting from 0), a represents the initial radius (when θ=0, r=a), and b represents the pitch (the radius increases by 2πb for every 2π radians increase).

[0065] Specifically, after the rotating axis moves to the specified starting radius position, the rotating axis is first controlled to accelerate to the second preset linear speed. After the linear speed reaches the standard, the rotating axis is controlled to perform spiral motion in the mode of an Archimedean spiral, thereby completing the spiral line scan of the second sub-area. The step length and pitch of the spiral line scan are equal to the effective length of the line spot.

[0066] Furthermore, after completely scanning the second sub-area, the method further includes:

[0067] 2.8. When a defect exists in the target image data, confirm the second row and column position information of the defect in the target image data.

[0068] 2.9. The polar coordinates of the defect in the wafer coordinate system are calculated by combining the second row and column position information, the second starting position, the radius and pitch of the Archimedean spiral.

[0069] Specifically, polar coordinates (R 1l ,θ 1l ) is calculated as:

[0070] a=R1-bθ1;

[0071]

[0072] Among them, (R1,θ1) is the coordinate of the second starting position, sp h is the row resolution, a is the initial radius, and b is the pitch.

[0073] 2.10. Calculate the Cartesian coordinates of the defect using polar coordinates and the shooting angle of the scanning camera.

[0074] Specifically, the Cartesian coordinates (x, y) of the defect are calculated as follows:

[0075] R s=(Wc)*sp w ;

[0076] x=R ol cos(θ ol )-R s cos(θ ol -θ c );

[0077] y=R ol sin(θ ol )-R s sin(θ ol -θ c );

[0078] Among them, sp w is the column-wise resolution, c is the number of columns where the defect is located, W is the image width, θ c is the angle between the scanning camera and the scanning direction.

[0079] Furthermore, the step of scanning the second area back and forth along a straight line in step S3 specifically includes:

[0080] 3.1. Fix the rotation axis and move the translation axis to the third starting position.

[0081] It should be noted that, in order to ensure that the second area can be completely scanned, the third starting position is located within the second sub-area, thereby ensuring that the boundary between the second sub-area and the second area can be completely scanned during scanning.

[0082] 3.2. Obtain the center position of the wafer and confirm the scanning direction based on the third starting position and the center position.

[0083] Specifically, after obtaining the third starting position and the center position, compare the horizontal coordinate values ​​of the third starting position and the center position. If the horizontal coordinate value of the third starting position is smaller than the horizontal coordinate value of the center position, it means that the third starting position is to the left of the center position, and the direction parallel to the horizontal coordinate axis from left to right is set as the scanning direction.

[0084] 3.3. Control the translation axis to perform a linear scan along the scanning direction. After completing a line of scanning, control the translation axis to move a preset step length perpendicular to the scanning direction, and then perform a linear scan in the direction opposite to the scanning direction. Repeat the above scanning process until the second area is completely scanned.

[0085] It should be understood that the second area is a circular area in structure. In order to avoid excessive repeated scanning data during scanning, Figure 2As shown, in this embodiment, when scanning the second area, a straight line passing through the center of the second area and perpendicular to the scanning direction is used as the central axis. For a point on the central axis that is farther from the center of the second area, the straight line scanning distance passing through the point is shorter, ensuring that the boundary between the second sub-area and the second area can be covered. For a point on the central axis that is closer to the center of the second area, the straight line scanning distance passing through the point is longer, also ensuring that the boundary between the second sub-area and the second area can be covered. This ensures that the entire second area is covered as much as possible while shortening the distance that the translation axis needs to move linearly.

[0086] Furthermore, after completely scanning the second area, the method further includes:

[0087] 3.4. When there is a defect in the target image data, confirm the third row and column position information of the defect in the target image data.

[0088] 3.5. Calculate the Cartesian coordinates of the defect based on the third starting position, the third row and column position information, and the shooting angle of the scanning camera.

[0089] Specifically, when calculating the Cartesian coordinates of a defect, the calculation method of its vertical axis coordinate is expressed as:

[0090] y=y0+(Wc)*sp w cos(θ c );

[0091] If the image data is collected while scanning along the scanning direction, the calculation method of the horizontal axis coordinate is expressed as:

[0092] x=x0+r*sp h +(Wc)*sp w sin(θ c );

[0093] If the image data is collected while scanning in the direction opposite to the scanning direction, the calculation method of the horizontal axis coordinate is expressed as:

[0094] x=x0-r*sp h -(Wc)*sp w sin(θ c );

[0095] Where (x, y) represents the Cartesian coordinates of the defect, (x0, y0) represents the second starting position information, r represents the starting and ending radius of the third area, sp h is the row resolution, sp w is the column-wise resolution, c is the number of columns where the defect is located, W is the image width, θ cis the angle between the scanning camera and the scanning direction. Furthermore, in this embodiment, due to the mixed scanning of the wafer surface using different scanning modes, the scanned image data may have some overlapping areas, especially the image data scanned before and after switching the scanning mode. To address this, this embodiment can intelligently merge the overlapping scan areas. For example, if the same location is scanned multiple times, only the most recent scan data can be retained. In addition, if a defect exists in the repeated area, the image data obtained by scanning the defect using different scanning modes can be pixel-weighted averaged to improve the signal-to-noise ratio (for example, the data weight of concentric circle scanning is 70%, and the data weight of spiral scanning is 30%).

[0096] The wafer scanning method of this embodiment divides the wafer surface into an annular first area occupying most of the wafer surface area and a circular second area including the center area of ​​the wafer. The annular first area is scanned by a spiral scanning method, which only requires one acceleration and deceleration process of the rotating axis, greatly reducing the time consumption caused by the repeated acceleration and deceleration process of the rotating axis, thereby greatly improving the scanning efficiency of the first area. For the center area of ​​the wafer, a straight line back and forth scanning method is adopted. On the one hand, it can achieve a complete scan of the center area, and on the other hand, it avoids the problem of reduced accuracy caused by spiral scanning when the scanning radius is too small, thereby ensuring scanning accuracy. And after the scanning is completed, for the area with defects, the present application can also use different coordinate reconstruction methods to reconstruct the coordinates according to different scanning methods, thereby improving the scanning coordinate accuracy and helping users quickly locate the position of the defective area on the wafer surface.

[0097] Figure 3 FIG is a functional module diagram of a wafer scanning device according to an embodiment of the present invention. Figure 3 As shown, the wafer scanning device 20 includes: an acquisition module 21 , a division module 22 and a scanning module 23 .

[0098] An acquisition module 21 is used to acquire the radius of the wafer to be scanned and the preset effective length of the line spot of the scanning camera;

[0099] a dividing module 22 for dividing the wafer into a first region and a second region based on the radius and the effective length of the line spot, wherein the first region includes an annular region having a radius greater than a first preset radius threshold, and the second region includes a circular region having a radius less than the first preset radius threshold;

[0100] The scanning module 23 is used to control the scanning camera to perform a spiral scan on the first area and then scan the second area back and forth along a straight line until the scanning is completed.

[0101] Optionally, the scanning module 23 executes the operation of controlling the scanning camera to perform a spiral scan on the first area, specifically including: dividing the first area into a first sub-area whose radius value is greater than a second preset radius threshold and a second sub-area whose radius value is between the first preset radius threshold and the second preset radius threshold, and the second preset radius threshold is greater than the first preset radius threshold; controlling the scanning camera to perform concentric circle scanning on the first sub-area and then perform a spiral scan on the second sub-area.

[0102] Optionally, the scanning module 23 executes the operation of controlling the scanning camera to perform concentric circle scanning on the first sub-area, specifically including: moving the rotating axis to the first sub-area according to the effective length of the line spot and the starting and ending radii of the first area; controlling the rotating axis to start accelerating and rotate at a uniform speed after accelerating to a first preset linear speed, and collecting a circle of image data at a frame rate during the uniform rotation stage, and recording the serial number of each frame of image data, and at the same time recording the first starting position of the first frame of image data collected by the concentric circle scanning.

[0103] Optionally, after the scanning module 23 performs the operation of recording the serial number of each frame of image data, it is also used to: when there is a defect in the target image data, confirm the first row and column position information of the defect in the target image data; calculate the polar coordinates of the defect in the wafer coordinate system by combining the first row and column position information and the first starting position; and use the polar coordinates and the shooting angle of the scanning camera to calculate the Cartesian coordinates of the defect.

[0104] Optionally, the scanning module 23 performs a spiral line scanning operation on the second sub-area, specifically including: moving the rotating axis to a specified starting radius position according to the effective length of the line spot and the starting and ending radii of the second sub-area; controlling the rotating axis to start accelerating and accelerate to a second preset linear speed, and then controlling the radius and angle of the rotating axis to perform spiral motion in the mode of an Archimedean spiral based on the step length set according to the effective length of the line spot, and collecting image data at a frame rate during the spiral motion stage, and recording the serial number of each frame of image data, and at the same time recording the second starting position of the first frame of image data collected by the spiral line scanning until the second sub-area is completely scanned.

[0105] Optionally, after performing the operation of fully scanning the second sub-area, the scanning module 23 is also used to: when a defect exists in the target image data, confirm the second row and column position information of the defect in the target image data; calculate the polar coordinates of the defect in the wafer coordinate system based on the second row and column position information, the second starting position, the radius and pitch of the Archimedean spiral; and calculate the Cartesian coordinates of the defect using the polar coordinates and the shooting angle of the scanning camera.

[0106] Optionally, the scanning module 23 performs an operation of scanning the second area back and forth along a straight line, specifically including: fixing the rotation axis and moving the translation axis to a third starting position; obtaining the center position of the wafer, and confirming the scanning direction based on the third starting position and the center position; controlling the translation axis to perform a straight line scan along the scanning direction, and after completing a line of scanning, controlling the translation axis to move a preset step length perpendicular to the scanning direction, and then performing a straight line scan in the direction opposite to the scanning direction, and repeating the above scanning process until the second area is completely scanned.

[0107] Optionally, after completely scanning the second area, scanning module 23 is further configured to: when a defect is present in the target image data, determine the third row and column position information of the defect in the target image data; and calculate the Cartesian coordinates of the defect based on the third starting position, the third row and column position information, and the imaging angle of the scanning camera. For further details on the technical solutions implemented by each module in the wafer scanning device of the above embodiment, please refer to the description of the wafer scanning method in the above embodiment and will not be repeated here.

[0108] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similarities between the various embodiments can be referred to in conjunction with each other. For device embodiments, since they are generally similar to method embodiments, their description is relatively simple, and for relevant details, reference can be made to the description of the method embodiments.

[0109] See also Figure 4 , Figure 4 FIG. 1 is a schematic diagram of the structure of a computer device according to an embodiment of the present invention. Figure 4 As shown, the computer device 30 includes a processor 31 and a memory 32 coupled to the processor 31. The memory 32 stores program instructions. When the program instructions are executed by the processor 31, the processor 31 executes the wafer scanning method steps described in any of the above embodiments.

[0110] The processor 31 may also be referred to as a resource (Central Processing Unit). The processor 31 may be an integrated circuit chip having signal processing capabilities. The processor 31 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The general-purpose processor may be a microprocessor or any conventional processor.

[0111] See Figure 5 , Figure 5Schematic diagram of the structure of the storage medium of an embodiment of the present invention. The storage medium of an embodiment of the present invention stores program instructions 41 that can implement the above-mentioned wafer scanning method, wherein the program instructions 41 can be stored in the above-mentioned storage medium in the form of a software product, including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, or a computer device such as a computer, a server, a mobile phone, or a tablet.

[0112] In the several embodiments provided in this application, it should be understood that the disclosed computer devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0113] In addition, the functional units in the various embodiments of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware or in the form of software functional units. The above is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A wafer scanning method, characterized in that: It includes: Obtaining the radius of the wafer to be scanned and the preset effective length of the line spot of the scanning camera; Dividing the wafer into a first area and a second area based on the radius and the effective length of the line spot, wherein the first area includes an annular area with a radius value greater than a first preset radius threshold, and the second area includes a circular area with a radius value less than the first preset radius threshold; The scanning camera is controlled to perform a spiral scan on the first area, and then scan the second area back and forth along a straight line until the scanning is completed.

2. The wafer scanning method according to claim 1, wherein: The controlling the scanning camera to perform a spiral scan on the first area includes: Dividing the first area into a first sub-area whose radius is greater than a second preset radius threshold and a second sub-area whose radius is between the first preset radius threshold and a second preset radius threshold, wherein the second preset radius threshold is greater than the first preset radius threshold; The scanning camera is controlled to perform concentric circle scanning on the first sub-area and then to perform spiral scanning on the second sub-area.

3. The wafer scanning method according to claim 2, wherein: The controlling the scanning camera to perform concentric circle scanning on the first sub-area includes: Move the rotation axis to the first sub-area according to the effective length of the line spot and the start and end radii of the first sub-area; The rotating shaft is controlled to start accelerating rotation and accelerate to a first preset linear velocity before rotating at a uniform speed. During the uniform rotation stage, a circle of image data is collected at a frame rate, and the serial number of each frame of image data is recorded. At the same time, the first starting position of the first frame of image data collected by concentric circle scanning is recorded.

4. The wafer scanning method according to claim 3, wherein: After recording the sequence number of each frame of image data, the method further includes: When a defect exists in the target image data, confirming first row and column position information of the defect in the target image data; Calculating the polar coordinates of the defect in the wafer coordinate system by combining the first row and column position information and the first starting position; The Cartesian coordinates of the defect are calculated using the polar coordinates and the shooting angle of the scanning camera.

5. The wafer scanning method according to claim 2, wherein: The performing a spiral line scan on the second sub-area includes: Move the rotation axis to a specified starting radius position according to the effective length of the line spot and the starting and ending radii of the second sub-area; After controlling the rotating shaft to start accelerating and accelerating to a second preset linear speed, the radius and angle of the rotating shaft are controlled to perform spiral motion in the mode of an Archimedean spiral based on the step length set based on the effective length of the linear spot, and image data is collected at a frame rate during the spiral motion stage, and the serial number of each frame of image data is recorded, and at the same time, the second starting position of the first frame of image data collected by the spiral line scanning is recorded until the second sub-area is completely scanned.

6. The wafer scanning method according to claim 5, characterized in that: After completely scanning the second sub-area, the method further includes: When a defect exists in the target image data, confirming second row and column position information of the defect in the target image data; Calculating the polar coordinates of the defect in the wafer coordinate system by combining the second row and column position information, the second starting position, the radius and pitch of the Archimedean spiral; The Cartesian coordinates of the defect are calculated using the polar coordinates and the shooting angle of the scanning camera.

7. The wafer scanning method according to claim 6, wherein: Scanning the second area back and forth along a straight line includes: Fix the rotation axis and move the translation axis to a third starting position; Obtaining a center position of the wafer, and determining a scanning direction based on the third starting position and the center position; The translation axis is controlled to perform a linear scan along the scanning direction, and after completing a line of scanning, the translation axis is controlled to move a preset step length perpendicular to the scanning direction, and then a linear scan is performed in the direction opposite to the scanning direction. The above scanning process is repeated until the second area is completely scanned.

8. The wafer scanning method according to claim 7, wherein: After completely scanning the second area, the method further includes: When a defect exists in the target image data, confirming the third row and column position information of the defect in the target image data; The Cartesian coordinates of the defect are calculated based on the third starting position, the third row and column position information, and the shooting angle of the scanning camera.

9. A computer device, characterized in that: The computer device includes a processor and a memory coupled to the processor, wherein program instructions are stored in the memory. When the program instructions are executed by the processor, the processor performs the steps of the wafer scanning method according to any one of claims 1 to 8.

10. A storage medium, characterized in that: Program instructions capable of implementing the wafer scanning method according to any one of claims 1 to 8 are stored.

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