A device and method for detecting the relative position of a polishing tape and a wafer notch

Abstract

The application discloses a kind of detection device and detection method of polishing belt and wafer gap relative position, it is related to semiconductor wafer manufacturing technical field.The detection device includes: image acquisition component, for before polishing process starts, respectively to the polishing belt and wafer gap area of polishing head is carried out image capture;Backlight, it is matched with polishing head setting, for when image capture provides backlight illumination;Light source controller, with backlight electric connection, for adjusting the brightness of the backlight;Processor, with the image acquisition component communication connection, the processor is configured as: the image of containing polishing belt and wafer gap that the image acquisition component captures is obtained;Identify the center of the center line of polishing belt and wafer gap in image;The vertical distance of the center of wafer gap to the center line of polishing belt is calculated;The vertical distance is compared with preset threshold value, if exceed threshold value then send alarm signal.

Description

Technical Field

[0001] This application relates to the field of semiconductor wafer manufacturing technology, and in particular to a device and method for detecting the relative position of the polishing strip and the wafer notch. Background Technology

[0002] In semiconductor wafer manufacturing processes, edge polishing is a critical step in improving wafer edge quality, reducing particle contamination, and preventing edge breakage. For wafers with notch structures, the polishing precision of the notch area directly affects subsequent photolithography alignment, wafer transfer, and overall yield.

[0003] Currently, wafer edge polishing equipment typically uses a polishing tape to locally polish wafer notches. Before the polishing process begins, the equipment first uses a precision positioning component to determine the accurate position of the wafer notch, and then rotates at a specific angle to move the wafer notch to a position aligned with the polishing tape. However, existing technology lacks a positional feedback or detection device to ensure that the polishing tape and wafer notch are truly aligned. The positional accuracy of the polishing tape and wafer notch depends entirely on the manufacturing and assembly precision of the transmission components, including but not limited to the encoder of the rotary chuck, the turning mechanism of the polishing head, and the mechanical fit of the positioning components. As the equipment operates for longer periods, the clearance between these components gradually increases, and the transmission precision decreases due to wear, resulting in a significant positional deviation between the wafer notch and the polishing tape. Because there are no corresponding detection or early warning methods, this deviation is often only discovered after a batch of polishing failures, causing substantial economic losses to wafer fabs.

[0004] Furthermore, during the equipment commissioning phase, operators typically rely solely on visual observation to determine the relative position of the polishing strip and the wafer notch. This method is prone to significant subjective error and is difficult to quantify. To ensure polishing quality, the factory also needs to periodically schedule manual re-inspections, which not only reduces the overall efficiency of the equipment but also increases labor costs.

[0005] Therefore, how to accurately and efficiently detect the relative position of the polishing strip and the wafer notch, and provide timely warnings when the deviation exceeds the limit, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of this, embodiments of this application provide a detection device and method for detecting the relative position of the polishing strip and the wafer notch, so as to at least partially solve the above-mentioned problems.

[0007] According to a first aspect of the embodiments of this application, a device for detecting the relative position of a polishing strip and a wafer notch is provided, comprising:

[0008] The image acquisition component is used to capture images of the polishing strip and wafer notch area at the polishing head before the polishing process begins.

[0009] A backlight, configured to match the polishing head, is used to provide backlight illumination during image capture;

[0010] A light source controller, electrically connected to the backlight, is used to adjust the brightness of the backlight;

[0011] A processor, communicatively connected to the image acquisition component, is configured to:

[0012] The image acquisition component captures an image containing the polishing band and wafer notch.

[0013] Identify the centerline of the polishing band and the center of the wafer notch in the image;

[0014] Calculate the vertical distance from the center of the wafer notch to the centerline of the polishing strip;

[0015] The vertical distance is compared with a preset threshold; if the distance exceeds the threshold, an alarm signal is issued.

[0016] In some embodiments, the polishing head includes a first polishing head and a second polishing head, which are matched with a first backlight and a second backlight, so that the brightness of the first backlight and the second backlight can be adjusted respectively by a light source controller.

[0017] In some embodiments, the processor identifies the centerline of the polishing strip by: selecting a first matching region and a second matching region in the image along the length direction of the polishing strip, fitting a first midpoint and a second midpoint of the polishing strip respectively, and determining a straight line as the centerline of the polishing strip based on the first midpoint and the second midpoint.

[0018] In some embodiments, the processor identifies the center of the wafer notch by: pre-storing a contour feature template of the wafer notch, performing feature retrieval within a matching region in the image, locating the notch contour that matches the template, and outputting the center coordinates of the notch contour.

[0019] In some embodiments, the image acquisition component includes a camera and a lens, and the detection device further includes an adjustment bracket assembly, which includes a rotation adjustment bracket, a horizontal adjustment bracket, and a base, for mounting and adjusting the position of the image acquisition component.

[0020] In some embodiments, the processor is further configured to: after the first polishing head and the second polishing head have switched to the detection position, sequentially control the image acquisition component to capture images at the first polishing head and the second polishing head respectively, and calculate the corresponding vertical distances respectively.

[0021] In some embodiments, the processor is configured to allow the polishing process to be executed only when the vertical distance between the first polishing head and the second polishing head does not exceed a preset threshold; otherwise, an alarm is issued and polishing is prohibited.

[0022] In some embodiments, the light source controller adjusts the brightness of the first backlight and the second backlight according to the difference in light transmittance of the polishing belts installed on the first polishing head and the second polishing head, so that the color difference gradient between the polishing belt and the wafer notch in the two captured images meets the recognition requirements.

[0023] According to a second aspect of the embodiments of this application, a detection method is provided, which uses the detection device described in any of the above claims to detect the relative position of the polishing strip and the wafer notch, and includes the following steps:

[0024] Step S1: Rotate the wafer to the polishing position and switch the first polishing head to the detection position;

[0025] Step S2: Use the image acquisition component to capture the image of the polishing strip and wafer notch at the first polishing head, while the first backlight provides backlight illumination;

[0026] Step S3: The processor identifies the centerline of the first polishing strip and the center of the first wafer notch in the image, calculates the first vertical distance, and determines whether it exceeds a preset threshold.

[0027] Step S4: Retract the first polishing head and switch the second polishing head to the detection position;

[0028] Step S5: Use the image acquisition component to capture the image of the polishing strip and wafer notch at the second polishing head, while the second backlight provides backlight illumination;

[0029] Step S6: The processor identifies the centerline of the second polishing strip and the center of the second wafer notch in the image, calculates the second vertical distance, and determines whether it exceeds a preset threshold.

[0030] Step S7: If neither the first vertical distance nor the second vertical distance exceeds the preset threshold, the polishing process is allowed; otherwise, an alarm is issued.

[0031] In some embodiments, steps S2 and S5 further include: adjusting the brightness of the first backlight and the second backlight respectively by means of a light source controller to adapt to the light transmittance of the current polishing belt.

[0032] In some embodiments, the processor identifies the centerline of the polishing strip by: selecting a first matching region and a second matching region in the image along the length direction of the polishing strip, fitting the first midpoint and the second midpoint of the polishing strip respectively, and determining a straight line as the centerline of the polishing strip based on the first midpoint and the second midpoint.

[0033] In some embodiments, the processor identifies the center of the wafer notch by: using a contour matching algorithm to slide and search a pre-stored notch contour template within the image matching area, calculating the similarity, locating the contour with the highest similarity, and outputting its center coordinates.

[0034] According to a third aspect of the embodiments of this application, a wafer edge polishing apparatus is provided, comprising:

[0035] A rotating chuck used to hold wafers;

[0036] The first polishing head and the second polishing head are used to polish the edges of the wafer, respectively.

[0037] And a detection device for the relative position of the polishing strip and the wafer notch as described in any of the above items.

[0038] In some embodiments, both the first polishing head and the second polishing head can switch between a polishing position and a detection position; when in the detection position, the field of view of the image acquisition component covers the polishing strip and the wafer notch area.

[0039] In some embodiments, the device further includes a wafer notch positioning component for coarse positioning of the wafer notch before polishing, and the detection device is used to perform fine detection of the relative position between the polishing strip and the wafer notch after coarse positioning is completed.

[0040] The beneficial effects of this invention include:

[0041] a. Improved polishing yield and equipment reliability. Before the polishing process begins, this invention automatically acquires an image of the relative position of the polishing strip and the wafer notch using a visual inspection device. It calculates the vertical distance from the notch center to the centerline of the polishing strip and compares it to a preset threshold. When the deviation exceeds the limit, an alarm is triggered immediately, and polishing is prohibited. This solution changes the passive situation in existing technologies that rely on the precision of transmission components without any position feedback. It effectively avoids batch polishing failures caused by loose positioning components or decreased transmission precision, significantly improving the yield of wafer notch polishing and the operational reliability of the equipment.

[0042] b. Improved inspection efficiency and reduced reliance on manual labor. This invention uses an image acquisition component and processor to automatically complete the alignment inspection of the polishing strip and wafer notch, replacing the traditional manual visual inspection method in debugging and periodic re-inspection. This eliminates subjective errors and achieves quantitative and traceable inspection results. At the same time, it eliminates the manual re-inspection step, improves the overall efficiency of wafer edge polishing equipment, and reduces labor costs.

[0043] c. Adapting to the detection needs of polishing strips with different transmittance. This invention addresses the dual-polishing-head structure by configuring an independent backlight for each polishing head, and adjusting the brightness of each backlight via a light source controller. Even if the polishing strips mounted on the two polishing heads have different transmittance, sufficient color difference gradients can be maintained between the polishing strip and the wafer notch in the two images captured by the image acquisition component, ensuring consistency and accuracy in software recognition and broadening the applicability of the device. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0045] Figure 1 This is a schematic diagram of a device for detecting the relative position of the polishing strip and the wafer notch according to an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of an image acquisition component provided in an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the backlight mounting position provided in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of an adjustment bracket assembly provided in an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of a wafer edge polishing device provided in an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram showing the distribution of the wafer edge polishing equipment performing the detection of the relative position between the polishing strip and the wafer notch;

[0051] Figure 7 It is used in wafer edge polishing equipment Figure 1 A flowchart illustrating the detection method using the detection device;

[0052] Figure 8This is a flowchart of the detection steps implemented by the detection device provided in an embodiment of the present invention;

[0053] Figure 9 This is a schematic diagram of wafer notch center fitting during the inspection process;

[0054] Figure 10 This is a schematic diagram of the fitting of the first center of the polishing strip during the testing process;

[0055] Figure 11 This is a schematic diagram of the fitting of the second center of the polishing strip during the detection process;

[0056] Figure 12 This is a schematic diagram of the fitting of the centerline of the polishing zone during the testing process;

[0057] Figure 13 This is a schematic diagram showing the vertical distance between the centerline of the polishing strip and the center of the wafer notch. Detailed Implementation

[0058] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0059] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0060] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified. A wafer (W) is also called a substrate, and its meaning and practical function are equivalent.

[0061] Figure 1This is a schematic diagram of a detection device 100 for the relative position of the polishing strip and the wafer notch according to an embodiment of the present invention. The detection device 100 is set in... Figure 5 The interior of the wafer edge polishing equipment 1000 shown is used for inspection. Figure 3 The relative position of the polishing strip 500 and the wafer notch is shown. The inspection device 100 mainly includes: an image acquisition component 10, a backlight 20, an adjustment bracket assembly 30, a light source controller 40, and a processor (not shown in the figure).

[0062] Figure 2 This is a schematic diagram of an image acquisition component 10 provided in an embodiment of the present invention. The image acquisition component 10 is used to image the polishing head 300 (…) before the polishing process begins. Figure 5 Image capture is performed on the polishing strip 500 and the wafer notch area (shown in the image).

[0063] In this embodiment, the image acquisition component 10 includes a camera 11 and a lens 12. The camera 11 can be an industrial camera, such as a CCD camera or a CMOS camera, with its resolution selected according to the required detection accuracy, typically 5 megapixels or higher. The lens 12 can be selected with a suitable focal length based on the working distance and field of view, such as a fixed-focus lens or zoom lens with specifications like 12mm, 16mm, or 25mm. The camera 11 and lens 12 work together to clearly capture the detailed features of the wafer notch and polishing strip 500 for subsequent image processing.

[0064] The image acquisition component 10 is mounted at an appropriate position in the wafer edge polishing equipment 1000 via the adjustment bracket assembly 30. For example... Figure 1 As shown, the field of view of the image acquisition component 10 is aligned with the area where the wafer notch is located, while also covering the area where the polishing strip 500 intersects with the wafer notch. The image acquisition component 10 is communicatively connected to the processor, transmitting the captured image to the processor in real time for analysis and processing.

[0065] In this invention, Figure 3 The backlight 20 shown is matched with the polishing head 300 to provide backlight illumination during image capture. The function of the backlight 20 is to create a large gradient color difference between the polishing belt 500, the wafer notch, and the environment, facilitating software identification of the center positions of the polishing belt 500 and the wafer notch. In this embodiment, the polishing head 300 includes a first polishing head 310 and a second polishing head 320. Correspondingly, the backlight 20 includes a first backlight 21 and a second backlight 22. The first backlight 21 is matched with the first polishing head 310, and the second backlight 22 is matched with the second polishing head 320.

[0066] In some embodiments, the first backlight 21 is mounted on the back or side of the first polishing head 310, and the second backlight 22 is mounted on the back or side of the second polishing head 320, such that the backlight direction is perpendicular to the wafer surface or opposite to the optical axis direction of the image acquisition component 10. This mounting method can ensure that the backlight is uniformly illuminated to the detection area, making the edge contours of the polishing strip 500 and the wafer notch clearly visible, and enhancing image contrast.

[0067] Furthermore, the light source controller 40 is electrically connected to the backlight 20 and is used to adjust the brightness of the backlight 20. In this embodiment, the light source controller 40 is electrically connected to the first backlight 21 and the second backlight 22 respectively, and can independently adjust the brightness of the first backlight 21 and the second backlight 22. The light source controller 40 can adjust the brightness of the first backlight 21 and the second backlight 22 respectively according to the difference in light transmittance of the polishing belt 500 installed on the first polishing head 310 and the second polishing head 320, so that the color difference gradient between the polishing belt 500 and the wafer notch in the two captured images meets the recognition requirements.

[0068] Specifically, when the light transmittance of the polishing belt 500 installed on the first polishing head 310 is low, the light source controller 40 can appropriately increase the brightness of the first backlight 21 to enhance the backlight penetration effect; when the light transmittance of the polishing belt 500 installed on the second polishing head 320 is high, the light source controller 40 can correspondingly reduce the brightness of the second backlight 22 to avoid image overexposure. Through this independent adjustment method, even if the light transmittance of the polishing belts 500 installed on the two polishing heads is different, it can be ensured that there is a sufficient color difference gradient between the polishing belt 500 and the wafer notch in the two images captured by the image acquisition component 10, ensuring the consistency and accuracy of subsequent image recognition.

[0069] Figure 1 In the illustrated embodiment, the detection device 100 further includes an adjustment bracket assembly 30. Figure 4 This is a schematic diagram of an adjustment bracket assembly 30 provided in an embodiment of the present invention. The adjustment bracket assembly 30 includes a rotary adjustment bracket 31, a horizontal adjustment bracket 32, and a base 33, used for mounting and adjusting the position of the image acquisition component 10. The base 33 is fixed to the frame of the wafer edge polishing equipment 1000, providing stable support. The horizontal adjustment bracket 32 ​​is mounted on the base 33 and can adjust the position of the image acquisition component 10 in the horizontal direction. The rotary adjustment bracket 31 is mounted on the horizontal adjustment bracket 32 ​​and can rotate about at least one axis to adjust the pitch and azimuth angles of the image acquisition component 10. The image acquisition component 10 is fixed to the rotary adjustment bracket 31.

[0070] By adjusting the bracket assembly 30, the image acquisition component 10 can be positioned at the optimal shooting position and angle during equipment installation and commissioning, ensuring that the field of view covers the polishing zone 500 and the wafer notch area, and guaranteeing image clarity and accuracy. Once adjusted, the bracket assembly 30 can be locked to maintain the stable position of the image acquisition component 10.

[0071] In this invention, a processor (not shown in the figure) is communicatively connected to the image acquisition component 10, and is used to receive images captured by the image acquisition component 10, and to process and analyze the images. The processor can be a standalone industrial control computer, an embedded computer, or it can be integrated into the main controller of the wafer edge polishing equipment 1000. The processor is configured to perform the following operations:

[0072] First, image acquisition. The processor receives an image captured by the image acquisition component 10, which includes the polishing strip 500 and the wafer notch. This image can be a grayscale image or a color image; in this embodiment, a grayscale image is preferred to reduce the amount of data processing.

[0073] Second, the centerline of the polishing strip is identified. The processor identifies the centerline of the polishing strip 500 in the image. Specifically, the processor selects a first matching region and a second matching region along the length direction of the polishing strip in the image, fits the first midpoint and the second midpoint of the polishing strip respectively, and determines a straight line as the centerline of the polishing strip based on the first midpoint and the second midpoint.

[0074] Third, the center of the wafer notch is identified. The processor identifies the center of the wafer notch in the image. Specifically, the processor pre-stores a contour feature template of the wafer notch, which is the standard contour shape of the wafer notch, usually V-shaped or U-shaped. Feature retrieval is performed within the matching region in the image, and a template matching algorithm is used to locate the notch contour that matches the template. The center coordinates of this notch contour are output as the center of the wafer notch. The template matching algorithm can be normalized cross-correlation matching, shape matching, etc.

[0075] Fourth, calculate the vertical distance. The processor calculates the vertical distance d from the wafer notch center to the centerline of the polishing strip 500 based on the wafer notch center coordinates and the centerline function of the polishing strip 500. Figure 13 (As shown). This vertical distance d is a quantitative indicator representing the relative position of the polishing strip 500 and the wafer notch. When d=0, it means that the center of the wafer notch is exactly located on the center line of the polishing strip 500, that is, it is in an ideal centering state; when d≠0, it means that there is an offset, and the larger the absolute value of d, the more serious the offset.

[0076] Fifth, comparison and alarm. The processor compares the calculated vertical distance d with a preset threshold T. The preset threshold T can be set in advance according to process requirements, such as 0.1mm, 0.2mm, or 0.05mm. If the vertical distance d exceeds the preset threshold T (i.e., |d|>T), the processor issues an alarm signal to notify the operator or equipment control system that the relative position between the polishing strip 500 and the wafer notch is out of tolerance and needs adjustment. If the vertical distance d does not exceed the preset threshold T (i.e., |d|≤T), it indicates that the current relative position is acceptable, and subsequent polishing processes can continue.

[0077] For a dual-polishing-head device with a first polishing head 310 and a second polishing head 320, the processor is further configured to: after the first polishing head 310 and the second polishing head 320 are switched to the detection position, sequentially control the image acquisition component 10 to capture the images at the first polishing head 310 and the second polishing head 320 respectively, and calculate the corresponding vertical distances d1 and d2 respectively.

[0078] Specifically, the processor first controls the first polishing head 310 to flip or move to the detection position, and then controls the image acquisition component 10 to capture images of the polishing strip 500 and the wafer notch at the first polishing head 310, identify the center line of the first polishing strip and the center of the first wafer notch, and calculate the first vertical distance d1. After completing the detection of the first polishing head 310, the processor controls the first polishing head 310 to return to its original position, and then controls the second polishing head 320 to flip or move to the detection position, and then controls the image acquisition component 10 to capture images of the polishing strip 500 and the wafer notch at the second polishing head 320, identify the center line of the second polishing strip and the center of the second wafer notch, and calculate the second vertical distance d2.

[0079] In this invention, the polishing process is only allowed when both the first vertical distance d1 and the second vertical distance d2 do not exceed the preset threshold T; otherwise, an alarm is issued and polishing is prohibited. This mechanism of sequential detection by dual polishing heads ensures that both polishing stations meet the alignment requirements, thereby guaranteeing the yield rate of the entire polishing process.

[0080] In addition, the present invention also provides a wafer edge polishing apparatus 1000, the schematic diagram of which is shown below. Figure 5 As shown. The wafer edge polishing equipment 1000 includes: a rotary chuck 200 for carrying the wafer, a first polishing head 310 and a second polishing head 320, a wafer notch positioning assembly 400, and a detection device 100 for detecting the relative position of the polishing belt and the wafer notch as described above.

[0081] The inspection device 100 is installed at an appropriate position within the wafer edge polishing equipment 1000. The image acquisition component 10 is fixed to the equipment frame via the adjustment bracket assembly 30 (e.g., ...). Figure 1As shown in the diagram, its field of view is aligned with the area where the wafer notch intersects with the polishing strip 500. The first backlight 21 is mounted on the back or side of the first polishing head 310, and the second backlight 22 is mounted on the back or side of the second polishing head 320. The light source controller 40 and the processor can be integrated into the electrical control cabinet of the device.

[0082] Figure 5 In this process, the rotary chuck 200 is used to adsorb and fix the wafer, while also driving the wafer to rotate around its central axis. The rotary chuck 200 typically uses a vacuum adsorption method, and its rotation angle and position are controlled by a high-precision servo motor and encoder. Before the polishing process begins, the rotary chuck 200 rotates the wafer to a preset polishing position based on the detection results of the wafer notch positioning component 400, aligning the wafer notch with the polishing area of ​​the polishing belt 500.

[0083] The first polishing head 310 and the second polishing head 320 are used to polish the wafer edge (especially the wafer notch area), respectively. Each polishing head 300 can switch between a polishing position and a detection position. In the polishing position, the polishing belt 500 contacts the wafer notch and performs the polishing operation; in the detection position, the field of view of the image acquisition component 10 covers the polishing belt 500 and the wafer notch area for relative position detection.

[0084] Specifically, the first polishing head 310 and the second polishing head 320 can be designed as a flip-up structure. When inspection is required, the polishing head flips down to the inspection position, so that the polishing belt 500 is within the field of view of the image acquisition component 10; after inspection, the polishing head flips up to return to its original position, or switches to the polishing position to perform polishing operations.

[0085] Figure 5 In this process, the wafer notch positioning component 400 is used to coarsely position the wafer notch before polishing. The wafer notch positioning component 400 can use optical sensors, mechanical positioning, or image recognition to determine the accurate position of the wafer notch. After coarse positioning is completed, the rotary chuck 200 rotates at a specific angle to move the wafer notch to a position aligned with the polishing belt 500 (i.e., the polishing position).

[0086] After receiving a signal from the wafer notch positioning component 400 indicating that positioning has been completed, the processor automatically triggers the detection device 100 to execute the detection process. This automatic triggering mechanism eliminates the need for manual intervention, automating the detection process and improving equipment operating efficiency.

[0087] See Figure 6 and Figure 7 The wafer edge polishing equipment 1000 performs the following process for detecting the relative position of the polishing strip and the wafer notch:

[0088] Step S101: The wafer notch positioning component 400 completes the precise positioning of the wafer notch.

[0089] Step S102: Rotate the chuck 200 back to the origin (or rotate it to the preset polishing position) so that the wafer notch is rotated to the position aligned with the polishing strip 500.

[0090] Step S103: The first polishing head 310 is switched to the polishing position and then flipped down to the detection position.

[0091] Step S104: The detection device 100 detects the relative position of the polishing strip 500 on the first polishing head 310 and the wafer notch.

[0092] Step S105: The first polishing head 310 retracts to its original position, the second polishing head 320 switches to the polishing position, and then flips down to the detection position.

[0093] Step S106: The detection device 100 detects the relative position of the polishing strip 500 on the second polishing head 320 and the wafer notch.

[0094] Step S107: If the detection results for both polishing heads are qualified (vertical distance does not exceed the threshold), the polishing process is allowed; otherwise, an alarm is issued.

[0095] In this invention, the processor is also used to record the vertical distance data for each detection and generate a trend graph. Specifically, the processor stores the first vertical distance d1 and the second vertical distance d2 obtained from each detection in the memory in chronological order. By analyzing the changing trends of these historical data, it can be determined whether the accuracy of the transmission or positioning components is gradually decreasing. For example, when the absolute value of the vertical distance shows a continuous increasing trend, even if it has not yet exceeded a preset threshold, an early warning can be issued to remind operators to perform preventative maintenance and avoid batch polishing failure due to a sudden deterioration in accuracy.

[0096] In some embodiments, the wafer edge polishing equipment further includes an alarm unit (not shown in the figure). The alarm unit may be an audible and visual alarm, an alarm prompt on a display screen, or a remote alarm message. When the processor determines that the vertical distance exceeds a preset threshold, it controls the alarm unit to issue an audible and visual alarm and suspend the polishing process. Simultaneously, the processor can also display the out-of-tolerance polishing head number and the vertical distance value on the equipment's human-machine interface, facilitating quick problem location and adjustment by the operator.

[0097] Furthermore, the preset threshold T is configurable according to process requirements. Different wafer sizes and polishing process parameters may have different requirements for the alignment accuracy between the polishing strip and the wafer notch. Therefore, the processor supports the storage and retrieval of different threshold parameters corresponding to different wafer sizes. Operators can set corresponding thresholds for different product types through the equipment's human-machine interface, and the processor automatically calls the threshold corresponding to the current product for comparison during detection.

[0098] Furthermore, the present invention also provides a detection method, which uses the detection device 100 described in Example 1 to detect the relative position of the polishing strip and the wafer notch. For example... Figure 7 and Figure 8 As shown, the method includes the following steps:

[0099] Step S1: Rotate the wafer to the polishing position and switch the first polishing head to the detection position.

[0100] After the wafer notch positioning assembly 400 completes the precise positioning of the wafer notch, the rotary chuck 200 rotates at a specific angle to move the wafer notch to a polishing position aligned with the polishing belt 500. Then, the first polishing head 310 is controlled to flip downwards or move to the detection position, so that the polishing belt 500 on the first polishing head 310 is within the field of view of the image acquisition assembly 10.

[0101] Step S2: Use the image acquisition component to capture the image of the polishing strip and wafer notch at the first polishing head, while the first backlight provides backlight illumination.

[0102] The processor controls the image acquisition component 10 to capture an image of the detection area at the first polishing head 310. Simultaneously, the light source controller 40 controls the first backlight 21 to illuminate, providing backlighting to the detection area. By adjusting the brightness of the first backlight 21, a clear color gradient can be created between the polishing band 500 and the wafer notch in the captured image, facilitating subsequent identification.

[0103] Step S3: The processor identifies the centerline of the first polishing strip and the center of the first wafer notch in the image, calculates the first vertical distance, and determines whether it exceeds a preset threshold.

[0104] The processor receives the image captured by the image acquisition component 10 and processes the image. The processing includes:

[0105] First, the centerline of the first polishing strip is identified. Specifically, the processor selects a first matching region and a second matching region along the length of the polishing strip in the image, fits the first midpoint and the second midpoint of the polishing strip respectively, and determines a straight line as the centerline of the first polishing strip based on the first midpoint and the second midpoint.

[0106] Secondly, the center of the first wafer notch is identified. Specifically, the processor uses a contour matching algorithm to slide and search the pre-stored notch contour template within the image matching area, calculate the similarity, locate the contour with the highest similarity, and output its center coordinates as the center of the first wafer notch.

[0107] Then, based on the function equation of the center coordinates of the first wafer notch and the center line of the first polishing strip, the vertical distance d1 from the center of the first wafer notch to the center line of the first polishing strip is calculated.

[0108] Finally, compare d1 with the preset threshold T. If d1≤T, the relative position at the first polishing head 310 is deemed acceptable; if d1>T, it is deemed out of tolerance.

[0109] Step S4: Retract the first polishing head and switch the second polishing head to the detection position.

[0110] After the first polishing head 310 is inspected, the processor controls the first polishing head 310 to flip upward or move back to its original position. Then, it controls the second polishing head 320 to flip downward or move to the inspection position, so that the polishing strip 500 on the second polishing head 320 is within the field of view of the image acquisition component 10.

[0111] Step S5: Use the image acquisition component to capture the image of the polishing strip and wafer notch at the second polishing head, while the second backlight provides backlight illumination.

[0112] The processor controls the image acquisition component 10 to capture an image of the detection area at the second polishing head 320. Simultaneously, the light source controller 40 controls the second backlight 22 to illuminate, providing backlighting to the detection area. It should be noted that since the light transmittance of the polishing belts 500 mounted on the first polishing head 310 and the second polishing head 320 may differ, the light source controller 40 can independently adjust the brightness of the second backlight 22 to differ from the brightness of the first backlight 21, ensuring that the contrast of both images meets the recognition requirements.

[0113] Step S6: The processor identifies the centerline of the second polishing strip and the center of the second wafer notch in the image, calculates the second vertical distance, and determines whether it exceeds the preset threshold.

[0114] The processing procedure in this step is similar to that in step S3. The processor identifies the centerline of the second polishing strip and the center of the second wafer notch, calculates the second vertical distance d2, and compares d2 with the preset threshold T.

[0115] Step S7: If neither the first vertical distance nor the second vertical distance exceeds the preset threshold, the polishing process is allowed; otherwise, an alarm is issued.

[0116] The processor comprehensively judges the results of d1 and d2. If d1≤T and d2≤T, it means that the relative positions of the polishing band 500 on both polishing heads and the wafer notch are both acceptable. The processor sends a "polishing allowed" signal to the equipment control system, and the equipment can continue to execute the polishing process. If d>T or d2>T (or both are out of tolerance), the processor issues an alarm signal, controls the alarm unit to issue an audible and visual alarm, and suspends the polishing process. At the same time, the number of the out-of-tolerance polishing head and the vertical distance value are displayed on the human-machine interface to remind the operator to check and adjust.

[0117] In steps S2 and S5 above, the brightness of the first backlight 21 and the second backlight 22 can be adjusted by the light source controller 40 to adapt to the current transmittance of the polishing belt 500. Specifically, during equipment debugging or after replacing the polishing belt 500, the operator can manually or automatically perform backlight brightness calibration: the first backlight 21 and the second backlight 22 are lit respectively, the image captured by the image acquisition component 10 is observed, and the brightness is adjusted until the color difference gradient between the polishing belt 500 and the wafer notch in the image meets the recognition requirements. The brightness parameters can be stored in the processor and automatically retrieved during subsequent detection.

[0118] Figure 8 This is a flowchart of the detection steps performed by the detection device provided in an embodiment of the present invention. Figure 8 This section details the core algorithm flow from image acquisition to outputting detection results, and this flow is consistent with... Figures 9 to 13 The image processing procedure shown corresponds to the intended meaning. The following is combined with... Figures 8 to 13 The image processing algorithm is explained in detail.

[0119] (a) Image Acquisition

[0120] A backlight 20 is used to create a low-grayscale bright background between the polishing strip and the wafer notch, while the backlight area presents a high grayscale contrast. By adjusting the light source parameters, the polishing strip to be detected, the backlight, and the wafer notch form a distinguishable grayscale difference in the acquired image.

[0121] (ii) Wafer notch center fitting

[0122] like Figure 9 As shown, in the captured image, the wafer notch typically appears as a V-shaped or U-shaped dark area (under backlighting). First, contour matching is performed. The processor pre-stores a contour feature template for the wafer notch, which contains the notch's standard shape, size, and orientation information. Feature retrieval is performed within the notch matching region R0 (i.e., the initial search range in the image) to locate the notch contour that matches this reference feature; and the center coordinates of this notch contour are output as the wafer notch center.

[0123] Specifically, the processor performs coarse matching to quickly locate the area where the notch may exist. The processor uses shape matching algorithms (such as edge gradient-based matching or contour-based matching) to perform feature retrieval and locate the notch contour that matches the reference feature. After a successful match, the center coordinates (x1, y1) of the notch contour are output as the wafer notch center.

[0124] (III) Polishing zone center fitting

[0125] Please see Figures 10 to 12 The polishing band 500 appears as a band-shaped area of ​​a certain width in the image. For example... Figure 8 As shown, the first step is to fit the first and second midpoints of the polishing strip, and then determine the centerline of the polishing strip based on these two midpoints. The specific process is as follows:

[0126] First, determine the matching region where the polishing band is located. Select the matching region in the image, which is the region of interest (ROI) where the polishing band is located. Specifically, when calculating the first center of the polishing band, the matching region is... Figure 10 The first matching region R1 is shown; when calculating the second center of the polishing band, the matching region is... Figure 11 The second matching area R2 is shown. This area should cover the full width and a certain length of the polishing belt 500 along its length. The matching area can be preset according to the preset position of the polishing head to reduce the search range and improve the processing speed.

[0127] Second, the image within the matching area is preprocessed: grayscale processing converts the color image to a grayscale image; filtering processing (such as median filtering and Gaussian filtering) removes noise interference; binarization processing (such as Otsu adaptive thresholding segmentation) segments the image into foreground (polishing band) and background.

[0128] Third, the rectangular contour of the polishing strip is fitted. Based on the preprocessed binary image, contour extraction algorithms (such as connected component analysis and rectangle fitting algorithms) are used to identify the rectangular region where the polishing strip is located, and the rectangular contour parameters of the polishing strip are obtained, including the position, width, length and rotation angle of the rectangle.

[0129] Fourth, the first midpoint of the polishing strip is fitted and calculated. For example... Figure 10As shown, based on the fitted rectangular contour parameters of the polishing belt, the coordinates of the first midpoint of the polishing belt are calculated. The area of ​​the polishing belt within the first matching region R1 is used as the criterion for judging the accuracy of the midpoint fitting position. Specifically, the processor calculates the area of ​​the polishing belt region within the first matching region R1 and compares it with a preset area threshold (determined according to the standard size of the polishing belt). If the deviation between the actual area and the standard area exceeds the allowable range (e.g., exceeding ±10%), the current midpoint fitting position is determined to be inaccurate, possibly due to excessive stretching deformation of the polishing belt, wear, contamination, or image quality issues. The processor issues an alarm signal, prompting the operator to check the polishing belt status or adjust the image acquisition parameters.

[0130] Fifth, the second midpoint fitting calculation of the polishing strip. For example... Figure 11 As shown, based on the fitted rectangular contour parameters of the polishing belt, the coordinates of the second midpoint of the polishing belt are calculated. The area of ​​the polishing belt within the second matching region R2 is used as the criterion for judging the accuracy of the midpoint fitting position. Similar to the first midpoint, the processor calculates the area of ​​the polishing belt region within the second matching region R2 and compares it with a preset area threshold. If the area exceeds the tolerance, an alarm signal is also issued. The first and second midpoints correspond to two different positions along the length of the polishing belt (e.g., positions near both ends of the polishing belt). This dual verification of the two midpoints ensures more reliable accuracy in polishing belt positioning.

[0131] Sixth, fitting the centerline of the polishing zone. For example... Figure 12 As shown, a straight line is determined as the centerline of the polishing belt based on the coordinates of the first and second midpoints. Specifically, let the coordinates of the first midpoint be (x1, y1) and the coordinates of the second midpoint be (x2, y2). Then, the functional equation of the centerline of the polishing belt is a straight line passing through these two points. For example, the slope k and intercept b can be obtained using the two-point equation:

[0132] k=(y2-y1) / (x2-x1)

[0133] b=y1-k·x1

[0134] The equation for the centerline of the polishing belt is: y = kx + b

[0135] (iv) Calculation of distance between points and lines

[0136] See Figure 13 The processor calculates the vertical distance d from the wafer notch center to the polishing strip centerline based on the wafer notch center coordinates (x1, y1) and the polishing strip centerline function (e.g., y=kx+b).

[0137] The obtained vertical distance d is the core indicator representing the relative position of the polishing strip 500 and the wafer notch. The processor compares the vertical distance d with a preset threshold T to determine whether it is qualified or not.

[0138] It should be understood that the above description is merely a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

[0139] For example, in other embodiments, the image acquisition component 10 may include multiple cameras and lenses, each corresponding to a different detection area. The backlight 20 may use light sources of different colors (such as red, blue, and white light) to adapt to polishing strips 500 of different materials and colors. The processor may employ deep learning algorithms (such as convolutional neural networks) to identify the centerline of the polishing strip and the center of the wafer notch, further improving the stability and accuracy of the detection.

[0140] Furthermore, the detection device 100 of the present invention is not limited to a dual-polishing-head device, but can also be applied to a single-polishing-head device or a multi-polishing-head device. For a single-polishing-head device, the structure and steps related to the second polishing head can be omitted, retaining only the first polishing head 310, the first backlight 21, and the corresponding detection process. For devices with more than two polishing heads, a backlight and detection steps can be added accordingly, and all polishing heads can be detected sequentially.

[0141] The detection device 100 and detection method of the present invention are not only applicable to the alignment detection of wafer notches before polishing, but can also be extended to other similar scenarios, such as the relative position detection of other feature structures (such as flat edges, markings, etc.) on the wafer edge with the polishing tool, as well as the alignment detection requirements in other semiconductor manufacturing processes.

[0142] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application.

[0143] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A device for detecting the relative position of a polishing strip and a wafer notch, characterized in that, include: The image acquisition component is used to capture images of the polishing strip and wafer notch area at the polishing head before the polishing process begins. A backlight, configured to match the polishing head, is used to provide backlight illumination during image capture; A light source controller, electrically connected to the backlight, is used to adjust the brightness of the backlight; A processor, communicatively connected to the image acquisition component, is configured to: The image acquisition component captures an image containing the polishing band and wafer notch. Identify the centerline of the polishing band and the center of the wafer notch in the image; Calculate the vertical distance from the center of the wafer notch to the centerline of the polishing strip; The vertical distance is compared with a preset threshold; if the distance exceeds the threshold, an alarm signal is issued.

2. The detection device according to claim 1, characterized in that, The polishing head includes a first polishing head and a second polishing head, which are matched with a first backlight and a second backlight, respectively, so that the brightness of the first backlight and the second backlight can be adjusted by a light source controller.

3. The detection device according to claim 1, characterized in that, The processor identifies the centerline of the polishing strip by: selecting a first matching region and a second matching region in the image along the length direction of the polishing strip, fitting the first midpoint and the second midpoint of the polishing strip respectively, and determining a straight line as the centerline of the polishing strip based on the first midpoint and the second midpoint.

4. The detection device according to claim 1, characterized in that, The processor identifies the center of the wafer notch by: pre-storing a contour feature template of the wafer notch, performing feature retrieval within the matching area in the image, locating the notch contour that matches the template, and outputting the center coordinates of the notch contour.

5. The detection device according to claim 1, characterized in that, The image acquisition component includes a camera and a lens, and the detection device further includes an adjustment bracket assembly, which includes a rotation adjustment bracket, a horizontal adjustment bracket, and a base, for mounting and adjusting the position of the image acquisition component.

6. The detection device according to claim 2, characterized in that, The processor is further configured to: after the first polishing head and the second polishing head have switched to the detection position, sequentially control the image acquisition component to capture images at the first polishing head and the second polishing head respectively, and calculate the corresponding vertical distance respectively.

7. The detection device according to claim 6, characterized in that, The processor is configured to allow the polishing process to be executed only when the vertical distance between the first polishing head and the second polishing head does not exceed a preset threshold; otherwise, an alarm is issued and polishing is prohibited.

8. The detection device according to claim 2, characterized in that, The light source controller adjusts the brightness of the first backlight and the second backlight according to the difference in light transmittance of the polishing belts installed on the first polishing head and the second polishing head, so that the color difference gradient between the polishing belt and the wafer notch in the two captured images meets the recognition requirements.

9. A detection method, comprising using the detection apparatus according to any one of claims 2 to 8 to detect the relative position of the polished strip and the wafer notch, characterized in that, Includes the following steps: Step S1: Rotate the wafer to the polishing position and switch the first polishing head to the detection position; Step S2: Use the image acquisition component to capture the image of the polishing strip and wafer notch at the first polishing head, while the first backlight provides backlight illumination; Step S3: The processor identifies the centerline of the first polishing strip and the center of the first wafer notch in the image, calculates the first vertical distance, and determines whether it exceeds a preset threshold. Step S4: Retract the first polishing head and switch the second polishing head to the detection position; Step S5: Use the image acquisition component to capture the image of the polishing strip and wafer notch at the second polishing head, while the second backlight provides backlight illumination; Step S6: The processor identifies the centerline of the second polishing strip and the center of the second wafer notch in the image, calculates the second vertical distance, and determines whether it exceeds a preset threshold. Step S7: If neither the first vertical distance nor the second vertical distance exceeds the preset threshold, the polishing process is allowed; otherwise, an alarm is issued.

10. The detection method according to claim 9, characterized in that, Steps S2 and S5 further include: adjusting the brightness of the first backlight and the second backlight respectively by means of a light source controller to adapt to the light transmittance of the current polishing belt.

11. The detection method according to claim 9, characterized in that, The processor identifies the centerline of the polishing strip by: selecting a first matching region and a second matching region along the length of the polishing strip in the image, fitting the first midpoint and the second midpoint of the polishing strip respectively, and determining a straight line as the centerline of the polishing strip based on the first midpoint and the second midpoint.

12. The detection method according to claim 9, characterized in that, The processor identifies the center of the wafer notch by: using a contour matching algorithm, sliding a pre-stored notch contour template within the image matching area, calculating the similarity, locating the contour with the highest similarity, and outputting its center coordinates.

13. A wafer edge polishing device, characterized in that, include: A rotating chuck used to hold wafers; The first polishing head and the second polishing head are used to polish the edges of the wafer, respectively. And a detection device for the relative position of the polishing strip and the wafer notch as described in any one of claims 2 to 8.

14. The wafer edge polishing equipment according to claim 13, characterized in that, Both the first polishing head and the second polishing head can switch between a polishing position and a detection position; when in the detection position, the field of view of the image acquisition component covers the polishing strip and the wafer notch area.

15. The wafer edge polishing equipment according to claim 13, characterized in that, The device also includes a wafer notch positioning component for coarse positioning of the wafer notch before polishing, and the detection device is used to perform fine detection of the relative position between the polishing strip and the wafer notch after coarse positioning is completed.

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