Wafer surface polishing ripple detection method and related device

Abstract

The invention discloses a wafer surface polishing ripple detection method and a related device, and the method comprises the steps: firstly, obtaining a walking path of a test platform; the test platform is used for placing a wafer; then, the test platform is driven based on the walking path; then, acquiring a plurality of acquisition images formed by receiving the laser reflected by the surface of the wafer by the laser receiving camera; the included angle between the scanning direction of the laser receiving camera and the surface of the wafer is a first angle, the incident angle of the laser is a second angle, and the first angle is different from the second angle; then, splicing a plurality of acquired images based on the walking path to obtain a target image; and finally, on the basis of a preset gray threshold and a pre-configured ripple model, detecting polishing ripples in the target image. Therefore, through combination of optical design optimization, automatic image acquisition and splicing and multi-dimensional defect judgment, the problem of low detection efficiency in the prior art is effectively solved, and a reliable scheme is provided for efficient and accurate detection of polishing ripples on the surface of the wafer.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a method and related apparatus for detecting polishing ripples on a wafer surface. Background Technology

[0002] Semiconductor wafers are the core substrate material used in the fabrication of semiconductor devices. As semiconductor devices develop towards higher power and higher frequency, the requirements for the surface flatness of semiconductor wafers are also increasing.

[0003] Semiconductor wafers, such as silicon carbide wafers or silicon wafers, are typically synthesized artificially. To achieve atomic-level flatness, chemical mechanical polishing (CMP) is usually required. However, factors such as the composition of the polishing slurry, the polishing pressure, and the rotation speed of the polishing disc can cause CMP ripples (polishing ripples) to form on the wafer surface after polishing. This affects the surface flatness and can lead to problems such as leakage in semiconductor devices manufactured using wafers with polishing ripples.

[0004] Currently, the detection of polishing ripples mainly relies on manual visual inspection. However, due to factors such as the experience of the inspectors and visual fatigue caused by long working hours, manual visual inspection is inefficient in identifying polishing ripples.

[0005] Therefore, improving the efficiency of identifying polishing ripples on the wafer surface has become a problem that needs to be solved. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a method and related apparatus for detecting polishing ripples on wafer surfaces, which can improve the efficiency of identifying polishing ripples on wafer surfaces.

[0007] The embodiments of this application disclose the following technical solutions:

[0008] In a first aspect, embodiments of this application provide a method for detecting polishing ripples on a wafer surface, the method comprising:

[0009] Obtain the travel path of the test platform; the test platform is used to place the wafer;

[0010] The test platform is driven based on the walking path;

[0011] Multiple images are acquired by a laser receiving camera receiving laser light reflected from the surface of a wafer; the scanning direction of the laser receiving camera forms a first angle with the surface of the wafer, and the incident angle of the laser light is a second angle, wherein the first angle is different from the second angle.

[0012] The target image is obtained by stitching together the multiple acquired images based on the walking path;

[0013] Based on a preset grayscale threshold and a pre-configured ripple model, polishing ripples in the target image are detected.

[0014] Optionally, detecting polishing ripples in the target image based on a preset grayscale threshold and a pre-configured ripple model includes:

[0015] Based on a preset grayscale threshold, the target region in the target image whose difference between light and dark grayscale is greater than the grayscale threshold is identified;

[0016] The target region is matched with a pre-configured ripple model to obtain the polishing ripple detection result of the target image.

[0017] Optionally, the step of performing feature matching between the target region and a pre-configured ripple model to obtain the polishing ripple detection result of the target image includes:

[0018] The target region is matched with a pre-configured ripple model to obtain the type of polishing ripples in the target image; the types of polishing ripples include severe ripples, slight ripples, and no ripples.

[0019] Optionally, before driving the test platform based on the walking path, the method further includes:

[0020] Get the scan speed;

[0021] The method of driving the test platform based on the walking path includes:

[0022] The test platform is driven based on the walking path and the scanning speed.

[0023] Optionally, the walking path includes at least one of an S-shaped walking path and a cross-shaped walking path.

[0024] Optionally, the walking path is an S-shaped walking path, and the spacing between adjacent scan lines in the S-shaped walking path is 2 mm.

[0025] Optionally, the walking path is a star-shaped walking path, wherein the angle between adjacent line segments in the star-shaped walking path is 45°.

[0026] Secondly, embodiments of this application provide a wafer surface polishing ripple detection device, the device comprising:

[0027] An acquisition module is used to acquire the travel path of the test platform; the test platform is used to place the wafer.

[0028] The driving module is used to drive the test platform based on the walking path;

[0029] The imaging module is used to acquire multiple images formed by a laser receiving camera receiving laser light reflected from the surface of a wafer; the scanning direction of the laser receiving camera is at a first angle to the surface of the wafer, and the incident angle of the laser light is a second angle, wherein the first angle is different from the second angle.

[0030] The stitching module is used to stitch together the multiple acquired images based on the walking path of the test platform to obtain the target image;

[0031] The detection module is used to detect polishing ripples in the target image based on a preset grayscale threshold and a pre-configured ripple model.

[0032] Thirdly, embodiments of this application provide a wafer surface polishing ripple detection device, the device comprising: a test platform, a laser receiving camera, a laser transmitter, and a host computer;

[0033] The host computer is electrically connected to the test platform, the laser receiving camera, and the laser transmitter;

[0034] The test platform is used to place the wafer; in response to the drive of the host computer, it moves according to a preset walking path;

[0035] The laser emitter is used to emit a laser at a preset second angle to the wafer surface in response to a start signal sent by the host computer.

[0036] The laser receiving camera is used to receive the laser reflected from the wafer surface in response to the shooting signal sent by the host computer, and to capture multiple images.

[0037] The host computer is used to execute the steps of the wafer surface polishing ripple detection method according to any embodiment of the first aspect.

[0038] Fourthly, embodiments of this application provide a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and when the computer program is run on a wafer surface polishing ripple detection device, the wafer surface polishing ripple detection device performs the steps of the wafer surface polishing ripple detection method described in any embodiment of the first aspect.

[0039] Compared with the prior art, this application has the following beneficial effects:

[0040] This application provides a method for detecting polishing ripples on a wafer surface. The method involves: first, acquiring the travel path of a test platform used to place the wafer; then, driving the test platform based on the travel path; next, acquiring multiple images formed by a laser receiving camera receiving laser light reflected from the wafer surface; the angle between the scanning direction of the laser receiving camera and the wafer surface is a first angle, and the incident angle of the laser light is a second angle, the first angle being different from the second angle; then, stitching the multiple acquired images together based on the travel path to obtain a target image; finally, detecting polishing ripples in the target image based on a preset grayscale threshold and a pre-configured ripple model.

[0041] Therefore, on the one hand, by pre-setting the test platform's walking path and driving the platform to scan, combined with image stitching to form a complete target image, it replaces manual visual inspection and local imaging, significantly shortening the inspection time and adapting to the high-efficiency inspection needs of large-scale production; on the other hand, by limiting the laser incident angle (second angle) to be different from the angle between the laser receiving camera's scanning direction and the wafer (first angle), it can effectively avoid the interference of specular reflection light. The diffuse reflection light in the ripple area can be stably received by the camera, while the specular reflection light in the flat area is not easy to enter the camera, improving the recognition of the ripple area signal from the optical source; furthermore, by combining the preset grayscale threshold and the pre-configured ripple model, it realizes a dual judgment combining the quantization threshold and morphological features. It can quickly lock suspicious areas through the grayscale threshold and distinguish ripples from other defects through the ripple model, reducing false detections and significantly improving the accuracy of polishing ripple detection. Attached Figure Description

[0042] 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 of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A flowchart of a wafer surface polishing ripple detection method provided in this application embodiment;

[0044] Figure 2 A schematic diagram of a detection principle provided in an embodiment of this application;

[0045] Figure 3 This is a schematic diagram of a polishing ripple morphology provided in an embodiment of this application;

[0046] Figure 4 A schematic diagram of a target area provided in an embodiment of this application;

[0047] Figure 5This application provides a schematic diagram of an S-shaped walking path.

[0048] Figure 6 A schematic diagram of a cross-shaped walking path provided in an embodiment of this application;

[0049] Figure 7 This is a schematic diagram of a wafer surface polishing ripple detection device provided in an embodiment of this application. Detailed Implementation

[0050] The wafer surface polishing ripple detection method and related apparatus provided in this application can be used in the semiconductor manufacturing field. The above is only an example and does not limit the application field of the wafer surface polishing ripple detection method and related apparatus provided in this application.

[0051] The terms "first," "second," "third," and "fourth," etc., used in this application specification, claims, and drawings are used to distinguish different objects, not to limit a specific order.

[0052] In the embodiments of this application, the terms "as an example" or "for example" are used to indicate that they are examples, illustrations, or explanations. Any embodiment or design that is described as "as an example" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of terms such as "as an example" or "for example" is intended to present the relevant concepts in a specific manner.

[0053] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0054] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0055] See Figure 1 The figure is a flowchart of a wafer surface polishing ripple detection method provided in an embodiment of this application. The method includes:

[0056] S101: Obtain the walking path of the test platform.

[0057] The testing platform is used to place the wafers.

[0058] As an example, the walking path of the test platform can include, but is not limited to, S-shaped walking paths and star-shaped walking paths. The spacing between adjacent scan lines in the S-shaped walking path and the angle between adjacent line segments in the star-shaped walking path can be flexibly set according to actual needs.

[0059] The scanning range of the travel path covers the entire wafer surface, including the edge areas. The travel path can be pre-programmed and generated by the host computer and stored in the control system of the test platform.

[0060] S102: Walking path driven test platform.

[0061] The wafer can be fixed to the test platform using methods such as mechanical chucks or vacuum adsorption. For example, the wafer center can be aligned with the rotation center of the test platform. Based on a path-driven test platform, it can move along the X and Y axes to scan the wafer surface.

[0062] As an example, before driving the test platform based on the walking path, the scanning speed can also be obtained, thus driving the test platform based on the walking path and scanning speed. For example, the scanning speed can be 1 mm / s to avoid blurring of the acquired images due to high-speed movement.

[0063] S103: Acquire multiple images formed by the laser receiving camera receiving the laser reflected from the wafer surface.

[0064] In this context, the angle between the scanning direction of the laser receiving camera and the wafer surface is the first angle, and the incident angle of the laser is the second angle. The first angle is different from the second angle.

[0065] Specifically, after chemical mechanical polishing, the wafer surface is mirror-like. If there are no defects such as polishing ripples, an incident laser at a certain angle will only be reflected at the same angle. If there are defects such as polishing ripples, diffuse reflection will occur in the defective areas.

[0066] In this embodiment, the first angle and the second angle are different. When the wafer surface is smooth and flat, the laser receiving camera will not receive reflected light signals, and the resulting image is dark. However, when there are defects on the wafer surface, such as polishing ripples, diffuse reflection will occur in the defective areas. This scattered light cannot regularly avoid the camera lens, and the laser emitted from the wafer surface will enter the camera lens, resulting in excessive exposure and forming a bright image. Figure 2 As shown.

[0067] As the test platform moves along the walking path, the laser receiving camera takes pictures of the laser reflected from the wafer surface at a pre-set shooting frequency, forming multiple acquired images. The brightness of the acquired images can be used to determine whether there are defects in the photographed area of ​​the wafer corresponding to the acquired images.

[0068] S104: The target image is obtained by stitching together multiple acquired images based on the walking path.

[0069] Specifically, multiple images captured by the laser receiving camera can be stitched together according to a walking path such as an S-shaped or a star-shaped walking path to obtain a target image of the entire wafer area.

[0070] S105: Detect polishing ripples in the target image based on a preset grayscale threshold and a pre-configured ripple model.

[0071] In addition to polishing ripples, wafer surfaces may also have other defects such as scratches, pits, or orange peel. In this embodiment, a ripple model is pre-configured, which can match the ripple model with the features extracted from the target image, thereby more accurately detecting polishing ripples in the target image.

[0072] As an example, polishing using mechanical rotating masks, such as chemical mechanical polishing, typically produces polishing ripples parallel to the main positioning edge of the wafer. The starting points of these ripples are located on both sides of the wafer surface, exhibiting typical characteristics. Figure 3 As shown, by establishing a database containing a large number of ripple morphology images and performing deep learning based on the database, a ripple model can be built, which can then accurately identify polishing ripples in the target image.

[0073] Based on the surface characteristics of wafers, flat areas will appear as a uniform dark black (grayscale value ≈ 50) in the target image, while wavy areas will have a significantly higher grayscale value (up to 100~150) due to enhanced diffuse reflection. Considering the requirements for the accuracy and precision of polishing wavy recognition, the grayscale threshold can be flexibly set in advance. For example, if it is necessary to recognize slight wavy areas and a certain percentage of false recognitions can be accepted, such as a non-wavy wafer being mistakenly identified as wavy, a smaller grayscale threshold can be set, such as ±15. If it is acceptable to miss extremely slight wavy areas, but it is desirable to improve the detection accuracy and reduce false recognitions, a larger grayscale threshold can be set, such as ±20.

[0074] Therefore, based on a preset grayscale threshold, target regions in the target image whose brightness difference exceeds the grayscale threshold can be identified, such as... Figure 4As shown, this figure is a schematic diagram of a target area provided in an embodiment of this application; then the target area is matched with a pre-configured ripple model to obtain the polishing ripple detection result of the target image. For example, the target area can be matched with a pre-configured ripple model to obtain the type of polishing ripple in the target image; wherein, the type of polishing ripple may include, but is not limited to, severe ripple, slight ripple and no ripple.

[0075] For example, the standard features of the ripple model may include features such as geometric features, gray-level distribution features, and spatial distribution features. The geometric features, gray-level distribution features, and spatial distribution features of the target area are extracted, and the extracted features are compared with the standard features of the ripple model to calculate the matching degree. The type of polishing ripple can then be classified based on the matching degree. Specifically, a matching degree higher than a preset first threshold can be classified as severe ripple; a matching degree lower than or equal to the first threshold but higher than a second threshold can be classified as slight ripple; and a matching degree lower than or equal to the second threshold can be classified as no ripple; wherein the first threshold is higher than the second threshold.

[0076] Therefore, the type of polishing ripples can be accurately classified based on the matching degree, and then the wafers can be classified according to the severity of the polishing ripples in the wafers, providing a basis for wafer grade classification. For example, wafers with severe ripples can be downgraded for use in low-precision devices, while wafers with slight ripples can be repaired through secondary polishing, thereby improving resource utilization, reducing production costs, and replacing manual subjective screening with standardized testing, thereby improving screening accuracy and reducing screening costs.

[0077] Optionally, after obtaining the polishing ripple detection results of the target image, the rippled areas can be selected on the target image using different colors. For example, a red box can be used to indicate severe ripples, and a yellow box can be used to indicate slight ripples. Key parameters such as type, area, and peak-to-valley grayscale difference can then be labeled. This allows for a visual and intuitive presentation of polishing ripple information to technicians.

[0078] Optionally, after obtaining the polishing ripple detection results of the target image, the total number, total area, and distribution location of severe and slight ripples on the wafer surface can be counted separately to provide data support for subsequent process adjustments. For example, if the statistics show that severe ripples are concentrated in a certain area, the wear of the corresponding polishing pad can be traced back to the location of the polishing pad, allowing for timely replacement of the polishing pad, avoiding continuous production of wafers with polishing ripples, and improving product yield.

[0079] In this embodiment, firstly, the travel path of the test platform is obtained; the test platform is used to place the wafer; then, the test platform is driven based on the travel path; next, multiple images are acquired by the laser receiving camera receiving the laser reflected from the wafer surface; the angle between the scanning direction of the laser receiving camera and the wafer surface is a first angle, and the incident angle of the laser is a second angle, the first angle being different from the second angle; then, the multiple acquired images are stitched together based on the travel path to obtain the target image; finally, polishing ripples in the target image are detected based on a preset grayscale threshold and a pre-configured ripple model.

[0080] Therefore, on the one hand, by pre-setting the test platform's walking path and driving the platform to scan, combined with image stitching to form a complete target image, it replaces manual visual inspection and local imaging, significantly shortening the inspection time and adapting to the high-efficiency inspection needs of large-scale production; on the other hand, by limiting the laser incident angle (second angle) to be different from the angle between the laser receiving camera's scanning direction and the wafer (first angle), it can effectively avoid the interference of specular reflection light. The diffuse reflection light in the ripple area can be stably received by the camera, while the specular reflection light in the flat area is not easy to enter the camera, improving the recognition of the ripple area signal from the optical source; furthermore, by combining the preset grayscale threshold and the pre-configured ripple model, it realizes a dual judgment combining the quantization threshold and morphological features. It can quickly lock suspicious areas through the grayscale threshold and distinguish ripples from other defects through the ripple model, reducing false detections and significantly improving the accuracy of polishing ripple detection.

[0081] In summary, this method, through the combination of optical design optimization, automated image acquisition and stitching, and multi-dimensional defect judgment, effectively solves the problems of low detection efficiency, weak anti-interference ability, and poor accuracy in existing methods, providing a reliable solution for efficient and accurate detection of polishing ripples on wafer surfaces.

[0082] As an example provided in this application, the wafer is a 4-inch silicon carbide (SiC) wafer; the test platform's travel path is an S-shaped travel path, with a spacing of 2 mm between adjacent scan lines in the S-shaped travel path, such as... Figure 5 As shown; the laser is a 630nm red laser with an incident angle of 45°; the scanning direction of the laser receiving camera is at an angle of 30° to the wafer surface; the laser receiving camera is equipped with a 5x objective lens with a focusing depth of 1μm.

[0083] In SiC wafers, the typical period of polishing ripples is 50-200 μm. The scan line spacing needs to be less than twice the minimum period of the ripples (i.e., ≤100 μm) to ensure that the ripple features are completely captured. However, in actual inspection, too small a line spacing will significantly increase the scanning time, so a balance must be struck between inspection accuracy and efficiency.

[0084] In this embodiment, a 5x objective lens is used, and the camera sensor pixel size is 10μm, resulting in a single-pixel resolution of approximately 2μm and a single image field of view of 5mm × 5mm. When the line spacing is set to 2mm, the overlap area between adjacent images is 3mm, ensuring that the ripple feature has at least 1.5mm of redundant coverage in adjacent images. This reduces missed detections due to image stitching errors and provides high scanning efficiency.

[0085] The laser receiving camera can capture one image every 0.5 seconds, and each image carries the corresponding test platform position information. Taking the acquisition of 200 images during the detection process as an example, the host computer can stitch the 200 images according to the coordinate relationship of the walking path. By matching image edge features, such as comparing the gray values ​​of overlapping areas of adjacent images, stitching misalignments are eliminated, and finally a complete global image of the wafer surface is formed, which is the target image.

[0086] The host computer can first filter out suspicious target areas in the target image by grayscale thresholding, such as areas where the difference between light and dark grayscale is greater than ±20; then call the ripple model to compare the features of the target area, such as direction, distribution and shape, with the ripple model to determine whether the target area has polishing ripples or non-ripple defects such as scratches or pits, and obtain the detection result.

[0087] As another example provided in this application, the wafer is an 8-inch silicon (Si) wafer; the test platform's travel path is a star-shaped travel path, that is, with the wafer center as the origin, eight scan lines radiate outwards, each scan line being 1.1 times the wafer radius in length; the angle between adjacent line segments in the star-shaped travel path is 45°, such as... Figure 6 As shown; the moving speed of the test platform is 1 mm / s; the laser is a 450 nm blue laser with a laser incident angle of 45°; the scanning direction of the laser receiving camera is at an angle of 30° to the wafer surface; the laser receiving camera is equipped with a 5x objective lens with a focusing depth of 1 μm.

[0088] The laser receiving camera can capture one image every second, with each image carrying the corresponding test platform location information. Taking 300 images captured during the inspection process as an example, the host computer can stitch the 300 images together based on the coordinate relationship of the walking path. By matching image edge features, such as comparing the gray values ​​of overlapping areas of adjacent images, stitching misalignments are eliminated, ultimately forming a complete global image of the wafer surface, which is the target image.

[0089] The host computer can first filter out suspicious target areas in the target image by using a grayscale threshold, such as areas where the difference between light and dark grayscale is greater than ±15; then call the ripple model to compare the features of the target area with the ripple model to obtain the detection results.

[0090] See Figure 7 The figure is a schematic diagram of a wafer surface polishing ripple detection device provided in an embodiment of this application. The device includes:

[0091] The acquisition module 701 is used to acquire the travel path of the test platform; the test platform is used to place the wafer.

[0092] Drive module 702 is used to drive the test platform based on the walking path;

[0093] The imaging module 703 is used to acquire multiple images formed by the laser receiving camera receiving the laser reflected from the wafer surface; the scanning direction of the laser receiving camera and the wafer surface are at a first angle, and the incident angle of the laser is a second angle, the first angle being different from the second angle;

[0094] The stitching module 704 is used to stitch multiple acquired images based on the walking path of the test platform to obtain the target image;

[0095] The detection module 705 is used to detect polishing ripples in a target image based on a preset grayscale threshold and a pre-configured ripple model.

[0096] Therefore, on the one hand, by pre-setting the test platform's walking path and driving the platform to scan, combined with image stitching to form a complete target image, it replaces manual visual inspection and local imaging, significantly shortening the inspection time and adapting to the high-efficiency inspection needs of large-scale production; on the other hand, by limiting the laser incident angle (second angle) to be different from the angle between the laser receiving camera's scanning direction and the wafer (first angle), it can effectively avoid the interference of specular reflection light. The diffuse reflection light in the ripple area can be stably received by the camera, while the specular reflection light in the flat area is not easy to enter the camera, improving the recognition of the ripple area signal from the optical source; furthermore, by combining the preset grayscale threshold and the pre-configured ripple model, it realizes a dual judgment combining the quantization threshold and morphological features. It can quickly lock suspicious areas through the grayscale threshold and distinguish ripples from other defects through the ripple model, reducing false detections and significantly improving the accuracy of polishing ripple detection.

[0097] Optionally, the detection module 705 includes an identification unit and a detection unit, wherein the identification unit is used to: identify target areas in the target image whose brightness difference is greater than the gray level threshold based on a preset gray level threshold; and the detection unit is used to: perform feature matching between the target area and a pre-configured ripple model to obtain the polishing ripple detection result of the target image.

[0098] Optionally, the detection unit is specifically used to: perform feature matching between the target region and a pre-configured ripple model to obtain the type of polishing ripples in the target image; the types of polishing ripples include severe ripples, slight ripples, and no ripples.

[0099] Optionally, some other wafer surface polishing ripple detection devices provided in this application also include a speed acquisition module for acquiring scanning speed; and a drive module 702, specifically used for driving the test platform based on the travel path and scanning speed.

[0100] This application embodiment also provides a wafer surface polishing ripple detection device, which includes: a test platform, a laser receiving camera, a laser transmitter, and a host computer;

[0101] The host computer is electrically connected to the test platform, the laser receiving camera, and the laser transmitter;

[0102] The test platform is used to place the wafer; in response to the drive of the host computer, it moves according to a preset walking path;

[0103] The laser emitter is used to emit a laser at a preset second angle to the wafer surface in response to a start signal sent by the host computer.

[0104] The laser receiving camera is used to receive the laser reflected from the wafer surface in response to the shooting signal sent by the host computer, and to capture multiple images.

[0105] The host computer is used to execute the steps of the wafer surface polishing ripple detection method described in any of the above embodiments.

[0106] In addition, this application also provides a computer-readable storage medium storing computer instructions, which, when executed on a wafer surface polishing ripple detection device, perform the steps of the above-described wafer surface polishing ripple detection method.

[0107] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the device and storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The device and storage medium embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0108] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for detecting polishing ripples on a wafer surface, characterized in that, The method includes: Obtain the travel path of the test platform; the test platform is used to place the wafer; The test platform is driven based on the walking path; Multiple images are acquired by a laser receiving camera receiving laser light reflected from the surface of a wafer; the scanning direction of the laser receiving camera forms a first angle with the surface of the wafer, and the incident angle of the laser light is a second angle, wherein the first angle is different from the second angle. The target image is obtained by stitching together the multiple acquired images based on the walking path; Based on a preset grayscale threshold and a pre-configured ripple model, polishing ripples in the target image are detected.

2. The method according to claim 1, characterized in that, The detection of polishing ripples in the target image based on a preset grayscale threshold and a pre-configured ripple model includes: Based on a preset grayscale threshold, the target region in the target image whose difference between light and dark grayscale is greater than the grayscale threshold is identified; The target region is matched with a pre-configured ripple model to obtain the polishing ripple detection result of the target image.

3. The method according to claim 2, characterized in that, The step of performing feature matching between the target region and a pre-configured ripple model to obtain the polishing ripple detection result of the target image includes: The target region is matched with a pre-configured ripple model to obtain the type of polishing ripples in the target image; the types of polishing ripples include severe ripples, slight ripples, and no ripples.

4. The method according to claim 1, characterized in that, Before driving the test platform based on the walking path, the method further includes: Get the scan speed; The method of driving the test platform based on the walking path includes: The test platform is driven based on the walking path and the scanning speed.

5. The method according to claim 1, characterized in that, The walking path includes at least one of an S-shaped walking path and a cross-shaped walking path.

6. The method according to claim 5, characterized in that, The walking path is an S-shaped walking path, and the spacing between adjacent scan lines in the S-shaped walking path is 2 mm.

7. The method according to claim 5, characterized in that, The walking path is a star-shaped walking path, and the angle between adjacent line segments in the star-shaped walking path is 45°.

8. A wafer surface polishing ripple detection device, characterized in that, The device includes: An acquisition module is used to acquire the travel path of the test platform; the test platform is used to place the wafer. The driving module is used to drive the test platform based on the walking path; The imaging module is used to acquire multiple images formed by a laser receiving camera receiving laser light reflected from the surface of a wafer; the scanning direction of the laser receiving camera is at a first angle to the surface of the wafer, and the incident angle of the laser light is a second angle, wherein the first angle is different from the second angle. The stitching module is used to stitch together the multiple acquired images based on the walking path of the test platform to obtain the target image; The detection module is used to detect polishing ripples in the target image based on a preset grayscale threshold and a pre-configured ripple model.

9. A wafer surface polishing ripple detection device, characterized in that, The equipment includes: a test platform, a laser receiving camera, a laser transmitter, and a host computer; The host computer is electrically connected to the test platform, the laser receiving camera, and the laser transmitter; The test platform is used to place the wafer; in response to the drive of the host computer, it moves according to a preset walking path; The laser emitter is used to emit a laser at a preset second angle to the wafer surface in response to a start signal sent by the host computer. The laser receiving camera is used to receive the laser reflected from the wafer surface in response to the shooting signal sent by the host computer, and to capture multiple images. The host computer is used to execute the steps of the wafer surface polishing ripple detection method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when run on a wafer surface polishing ripple detection device, performs the steps of the wafer surface polishing ripple detection method as described in any one of claims 1-7.

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