A method for calculating the edge wash spacing in copper electroplating

Abstract

The present invention provides a method for calculating the edge washing spacing in copper electroplating, comprising the following steps: providing a wafer that has been processed with copper edge washing, and obtaining an image of at least one acquisition position of the wafer at the crystal edge; pre-processing each of the images according to grayscale brightness to lock a first target area where the copper edge position at each acquisition position is located, and a second target area where the crystal edge position at each acquisition position is located; obtaining a straight line where the copper edge washing position of each acquisition position is located in the first target area through straight line detection, and obtaining a straight line where the crystal edge position of each acquisition position is located in the second target area, and calculating the distance between the straight line where the copper edge washing position of each acquisition position is located and the straight line where the crystal edge position is located, so that the present invention can realize the calculation of the edge washing spacing in copper electroplating without a special optical system device, thereby reducing costs and not affecting measurement results.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor manufacturing, and in particular to a method for calculating edge-washing spacing in copper electroplating. Background Art

[0002] In the manufacture of integrated circuits, since the current needs to flow between different components inside the chip, wires are needed to connect these different components. As chip size continues to decrease and performance continues to improve, copper has gradually replaced aluminum as the mainstream wire material. Among them, the most critical step in forming copper wires is electrochemical plating (ECP). ECP is to deposit a thin layer of copper on the surface of the chip. The copper in the copper layer is filled into tiny structures such as lattices and holes to form precise copper wires. However, in this process, uneven edge areas may be formed at the edge of the wafer, causing metal contamination and affecting subsequent process steps.

[0003] In order to solve the above problems, the industry usually needs to use the EBR (Edge Bevel Removal) edge cleaning process. The EBR edge cleaning process sprays chemical solvents to the edge of the wafer through the EBR nozzle to wash away the copper at the edge of the wafer. After the edge cleaning process is completed, the edge cleaning distance needs to be measured to measure the edge cleaning effect.

[0004] However, there are usually two methods for measurement after the EBR edge cleaning process. Method 1 requires a special optical system device for measurement. At the same time, the device needs to be regularly cleaned, maintained, calibrated and adjusted, which is time-consuming, labor-intensive and costly. Method 2 is manual measurement using a length measuring tool, which has measurement errors and is prone to secondary contamination of the wafer. Summary of the invention

[0005] The object of the present invention is to provide a method for calculating the edge cleaning spacing in copper electroplating without requiring a special optical system device, which can reduce costs and does not affect the measurement results.

[0006] In order to solve the above problems, the present invention provides a method for calculating the edge washing spacing in copper electroplating, comprising the following steps:

[0007] Providing a wafer that has been subjected to copper edge cleaning treatment, and obtaining an image of at least one acquisition position at the wafer edge of the wafer;

[0008] Preprocessing each of the images according to grayscale brightness to lock a first target area where the copper edge position at each acquisition position is located, and a second target area where the crystal edge position at each acquisition position is located;

[0009] The straight line where the copper washing edge position of each acquisition position is located is obtained in the first target area through straight line detection, and the straight line where the crystal edge position of each acquisition position is located is obtained in the second target area, and the distance between the straight line where the copper washing edge position of each acquisition position is located and the straight line where the crystal edge position is located is calculated.

[0010] Optionally, each of the acquisition positions corresponds to a picture, and the picture includes a copper edge position and a crystal edge position.

[0011] Furthermore, the specific method of locking the first target area and the second target area is:

[0012] Measuring the grayscale brightness at four corner positions of the image at each acquisition position, and when the grayscale brightness at at least one corner position of the image approaches the minimum grayscale brightness value, calculating and finding the area with the most obvious brightness gradient change in each image, so as to achieve preliminary locking of the first target area and the second target area;

[0013] The image at the acquisition position is preprocessed by using filtering operation and morphological operation to lock the range of the first target area and the second target area.

[0014] Furthermore, when the grayscale brightness at the four corners of the image all tends to the grayscale brightness maximum value, it is determined that the edge washing is seriously insufficient, and an edge washing insufficient alarm is issued.

[0015] Furthermore, the specific method of preprocessing is:

[0016] The image at the acquisition position is subjected to Gaussian blur processing;

[0017] Dilate and corrode the image at the acquisition position, so as to expand the contour of the object in each of the images by dilation to obtain a dilated image, and simultaneously shrink the contour of the object in the image by corroding to obtain a corroded image;

[0018] Subtract the eroded image from the dilated image.

[0019] Furthermore, the specific method for obtaining the straight line where the copper washing edge position of each collection position is located and the straight line where the crystal edge position of each collection position is located is:

[0020] Performing superpixel segmentation on the image, and performing straight line detection on the image before and after the superpixel segmentation, respectively, to find out all straight lines that may be copper edge positions in the first target area, and all straight lines that may be crystal edge positions in the second target area;

[0021] The Hough line detection fusion method is used to merge the partial lines before and after the superpixel segmentation in the first target area, and the partial lines before and after the superpixel segmentation in the second target area are merged respectively;

[0022] Merge the remaining straight lines in the first target area of ​​each image before superpixel segmentation with the remaining straight lines in the first target area after superpixel segmentation, and merge the remaining straight lines in the second target area of ​​each image before superpixel segmentation with the remaining straight lines in the second target area after superpixel segmentation;

[0023] The straight lines with the largest number of votes in the first target area and the second target area are respectively selected by probability to lock the straight line where the copper washing edge position and the straight line where the crystal edge position of each acquisition position are located.

[0024] Optionally, each of the acquisition positions corresponds to a first picture and a second picture, the first picture includes a copper edge position, and the second picture includes a crystal edge position.

[0025] Furthermore, the specific method of locking the first target area and the second target area is:

[0026] Measuring the grayscale brightness at four corner positions of the first image and the second image at each acquisition position, and when the grayscale brightness at at least one corner position of the first image or the second image approaches the minimum grayscale brightness, calculating and finding the position information of the area with the most obvious brightness gradient change in the first image and the second image at each acquisition position, so as to achieve preliminary locking of the first target area of ​​the first image and the second target area of ​​the second image;

[0027] The first image and the second image at each acquisition position are preprocessed by using filtering operations and morphological operations to lock the range of the first target area of ​​the first image and the range of the second target area of ​​the second image.

[0028] Furthermore, the specific method for obtaining the straight line where the copper washing edge position and the straight line where the crystal edge position of each collection position are located is:

[0029] Performing superpixel segmentation on the first image and the second image at each acquisition position respectively, and performing straight line detection on the first image before and after the superpixel segmentation to find out all straight lines that may be copper edge positions in the first target area; performing straight line detection on the second image before and after the superpixel segmentation to find out all straight lines that may be crystal edge positions in the second target area;

[0030] The Hough line detection fusion method is used to merge the partial straight lines before and after the superpixel segmentation in the first target area of ​​the first image at each acquisition position, and the partial straight lines before and after the superpixel segmentation in the second target area of ​​the second image at each acquisition position are merged respectively;

[0031] Merge the remaining straight lines in the first target area of ​​the first image at each acquisition position before superpixel segmentation with the remaining straight lines in the first target area of ​​the first image at each acquisition position after superpixel segmentation; merge the remaining straight lines in the second target area of ​​the second image at each acquisition position before superpixel segmentation with the remaining straight lines in the second target area of ​​the second image at each acquisition position after superpixel segmentation;

[0032] The straight lines with the largest number of votes in the first target area and the second target area are respectively selected by probability to lock the straight line where the copper washing edge position and the straight line where the crystal edge position of each acquisition position are located.

[0033] Further, before calculating the distance between the straight line where the copper washing edge position of each collection position is located and the straight line where the crystal edge position is located, it specifically includes:

[0034] The first image and the second image at each acquisition position are spliced, and the distance between the straight line where the copper edge washing position of each acquisition position is located and the straight line where the crystal edge position is located is calculated in the spliced ​​image to obtain the edge washing distance.

[0035] Compared with the prior art, the present invention has the following unexpected technical effects:

[0036] The present invention provides a method for calculating the edge washing spacing in copper electroplating, comprising the following steps: providing a wafer that has been processed with copper edge washing, and obtaining an image of at least one acquisition position of the wafer at the crystal edge; pre-processing each of the images according to grayscale brightness to lock a first target area where the copper edge position at each acquisition position is located, and a second target area where the crystal edge position at each acquisition position is located; obtaining a straight line where the copper edge washing position of each acquisition position is located in the first target area through straight line detection, and obtaining a straight line where the crystal edge position of each acquisition position is located in the second target area, and calculating the distance between the straight line where the copper edge washing position of each acquisition position is located and the straight line where the crystal edge position is located, so that the present invention can realize the calculation of the edge washing spacing in copper electroplating without a special optical system device, thereby reducing costs and not affecting measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic flow chart of a method for calculating edge-washing spacing in copper electroplating provided in one embodiment of the present invention.

[0038] Figure 2 A schematic structural diagram of a wafer provided in one embodiment of the present invention.

[0039] Figure 3 It is a schematic diagram of a second target area obtained by preprocessing in a second image at a collection position in a second embodiment of the present invention.

[0040] Figure 4 It is a schematic diagram of the first picture and the second picture at each acquisition position after being spliced ​​in the second embodiment of the present invention.

[0041] Figure 5 It is a schematic diagram of the first picture and the second picture after splicing at the acquisition position when picture loss occurs in the second embodiment of the present invention.

[0042] Description of reference numerals:

[0043] 10-crystal edge area; 11-copper film layer; 20-collection position; 21-first target area; 22-second target area; 31-first picture; 32-second picture. DETAILED DESCRIPTION

[0044] A method for calculating the edge wash spacing in copper electroplating of the present invention will be described in further detail below. The present invention will be described in more detail below with reference to the accompanying drawings, in which preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art can modify the present invention described herein and still achieve the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation of the present invention.

[0045] For the sake of clarity, not all features of the actual embodiments are described. In the following description, well-known functions and structures are not described in detail because they would clutter the invention with unnecessary detail. It should be recognized that in the development of any actual embodiment, a large number of implementation details must be made to achieve the developer's specific goals, such as changing from one embodiment to another according to the limitations of the relevant system or the relevant business. In addition, it should be recognized that such development work may be complex and time-consuming, but it is just a routine task for those skilled in the art.

[0046] In order to make the purpose and features of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are all in a very simplified form and use inaccurate ratios, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0047] like Figure 1 As shown, the present invention provides a method for calculating the edge washing spacing in copper electroplating, comprising the following steps:

[0048] Step S1: providing a wafer that has been subjected to copper edge cleaning treatment, and obtaining an image of at least one acquisition position at the wafer edge of the wafer;

[0049] Step S2: pre-processing each of the images according to grayscale brightness to lock a first target area where the copper edge of each acquisition position is located, and a second target area where the crystal edge of each acquisition position is located;

[0050] Step S3: obtaining the straight line where the copper washing edge position of each acquisition position is located in the first target area through straight line detection, and obtaining the straight line where the crystal edge position of each acquisition position is located in the second target area, and calculating the distance between the straight line where the copper washing edge position of each acquisition position is located and the straight line where the crystal edge position is located.

[0051] Embodiment 1

[0052] A method for calculating the edge-washing spacing in copper electroplating provided by the present invention is described in detail below with reference to the diagrams.

[0053] See also Figure 2 First, step S1 is performed to provide a wafer that has been processed by copper edge cleaning, and obtain a picture of at least one acquisition position 20 at the wafer edge of the wafer.

[0054] This step specifically includes the following steps:

[0055] First, a copper-plated wafer is provided, the surface of the wafer having a copper film layer 11, and the wafer is subjected to a copper edge washing treatment to expose a wafer edge region 10 of the wafer. The wafer edge region 10 is the wafer surface exposed after the copper film layer 11 is washed away, the wafer edge region 10 is in a circular ring shape, and the inner ring of the crystal edge region 10 is the copper edge position after the copper edge washing treatment, and the outer ring of the crystal edge region 10 is the crystal edge position.

[0056] Next, at least one collection position 20 is determined on the wafer, each of the collection positions 20 is evenly distributed at the edge of the wafer along the circumferential direction, and each of the collection positions 20 includes a partial crystal edge area 10, a copper mold layer area inside the partial crystal edge area 10, and an environmental area outside the partial crystal edge area 10.

[0057] In this embodiment, four acquisition positions 20 are determined on the wafer, and the four acquisition positions 20 are respectively a first acquisition position 20, a second acquisition position 20, a third acquisition position 20 and a fourth acquisition position 20. The first acquisition position 20, the second acquisition position 20, the third acquisition position 20 and the fourth acquisition position 20 are arranged at the edge of the wafer along the circumferential direction. The first acquisition position 20, the second acquisition position 20 and the fourth acquisition position 20 are arranged at equal intervals. The first acquisition position 20 is arranged opposite to the wafer notch Notch, the second acquisition position 20 and the fourth acquisition position 20 are arranged opposite to each other, and the third acquisition position 20 is located near the wafer notch to avoid the notch.

[0058] Next, a complete picture of each of the acquisition positions 20 is obtained, and the complete picture consists of one picture, that is, each of the acquisition positions 20 corresponds to one picture. At this time, a picture of the acquisition position 20 is taken above each of the acquisition positions 20, and the taken picture includes the copper edge position and the crystal edge position at the acquisition position 20.

[0059] Then, step S2 is performed to pre-process each of the images according to grayscale brightness to lock the first target area 21 where the copper edge of each acquisition position 20 is located, and the second target area 22 where the crystal edge of each acquisition position 20 is located.

[0060] This step specifically includes the following steps:

[0061] First, measure the grayscale brightness at the four corners of the image at each of the acquisition positions 20. When the grayscale brightness at the four corners of the image tends to the maximum grayscale brightness, it is determined that the edge washing is seriously insufficient, and an alarm for insufficient edge washing is issued; when the grayscale brightness at at least one corner of the image tends to the minimum grayscale brightness, the subsequent steps are performed. Since the brightness of the copper film layer 11 is large and close to white in the image, the insufficient edge washing is determined by measuring the grayscale brightness of the four corners of the image at the acquisition position 20. In this embodiment, the brightness grayscale is 256 levels, i.e., 0~255 levels. Therefore, when the grayscale brightness at the four corners of the image tends to 255 levels, it is determined that the edge washing is seriously insufficient; when the grayscale brightness at at least one corner of the image tends to 0, the subsequent steps are continued.

[0062] Next, the area with the most obvious brightness gradient change in each of the images is calculated and found to achieve preliminary locking of the first target area 21 and the second target area 22. Specifically, the change rate of the pixel brightness at each coordinate position in the image at the acquisition position 20 is first calculated, and then the position information of the area with obvious brightness change (for example, the area with the most obvious brightness gradient change in the top 1%) is traversed and compared and fed back to convert the spatial distribution analysis of the gradient information of the image into the calculation of the relationship with the coordinate position, and the dynamic threshold is used to locate the area with obvious brightness gradient change in the image to complete the preliminary locking.

[0063] Next, the image at the acquisition position 20 is preprocessed by using filtering operations and morphological operations to enhance the image edge information, thereby reducing and locking the range of the first target area 21 and the second target area 22. Specifically, the image at the acquisition position 20 is first subjected to Gaussian blur processing to reduce noise and details in the image by convolving the image with a Gaussian kernel through a discrete representation Gaussian function; the image at the acquisition position 20 is then dilated and eroded to expand the contour of each object in the image through dilation to obtain a dilated image, which makes the edge of the object in the image more blurred, and the contour of the object in the image is contracted through corrosion to obtain a corroded image, which makes the edge of the object in the image clearer; and the corroded image is subtracted from the dilated image to highlight the area with a clear transition.

[0064] Then, step S3 is performed to obtain the straight line where the copper washing edge position of each collection position 20 is located in the first target area 21 through straight line detection, and obtain the straight line where the crystal edge position of each collection position 20 is located in the second target area 22, and calculate the distance between the straight line where the copper washing edge position of each collection position 20 is located and the straight line where the crystal edge position is located.

[0065] This step specifically includes the following steps:

[0066] First, the image is segmented into superpixels, and straight line detection is performed on the image before and after the superpixel segmentation to find out all straight lines that may be copper edge positions in the first target area 21 and all straight lines that may be crystal edge positions in the second target area 22.

[0067] Next, the Hough line detection fusion method is used to merge the partial straight lines before and after the superpixel segmentation in the first target area 21, and the partial straight lines before and after the superpixel segmentation in the second target area 22 are merged. In detail, in the Hough transform method, a distance threshold is set, and the partial straight lines of the first target area 21 and the second target area 22 in the image before and after the superpixel segmentation are merged by the distance threshold to reduce redundant information, thereby preliminarily locking the straight line in the first target area 21 that may be the copper washing edge position, and the straight line in the second target area 22 that may be the crystal edge position.

[0068] During the merging process, in Hough space, polar coordinates can be used to represent the line parameters in the Hough transform, so as to calculate the distance between two lines. The polar coordinate form is expressed as (ρ, θ), where ρ is the length of the vertical line from the origin to the line, and θ is the angle between the vertical line and the horizontal axis. The distance calculation is used to merge lines with the same ρ but different θ; at the same time, the lines outside the distance threshold are removed. At this time, there may be more than one straight line at the copper edge position, and there may also be more than one straight line at the crystal edge position.

[0069] The line detection in this step adopts the method of fusion of superpixel segmentation and Hough line detection to combine local information and global information, which can be applied to more complex scenes and improve robustness.

[0070] Next, the remaining straight lines of each image in the first target area 21 before superpixel segmentation are merged with the remaining straight lines in the first target area 21 after superpixel segmentation, and the remaining straight lines of each image in the second target area 22 before superpixel segmentation are merged with the remaining straight lines in the second target area 22 after superpixel segmentation.

[0071] Next, the straight lines with the largest number of votes in the first target area 21 and the second target area 22 are respectively selected by probability to lock the straight line where the copper washing edge position and the straight line where the crystal edge position of each of the acquisition positions 20 are located.

[0072] Next, the distance between the straight line where the copper edge position of each collection position 20 is located and the straight line where the crystal edge position is located is calculated to obtain the edge washing distance, thereby completing the edge washing distance measurement of each collection position 20 and outputting the measurement result.

[0073] Embodiment 2

[0074] Compared with the first embodiment, in step S1 of the present embodiment, the complete picture of each acquisition position 20 needs to be formed by stitching two pictures. At this time, each acquisition position 20 needs to take two pictures, namely, a first picture 31 and a second picture 32. The first picture 31 needs to be taken from the center of the wafer at a first preset angle toward the acquisition position 20; the second picture 32 needs to be taken from the outside of the wafer at a second preset angle toward the acquisition position 20. In other words, each acquisition position 20 corresponds to a first picture 31 and a second picture 32, the first picture 31 includes the copper edge position, and the second picture 32 includes the crystal edge position.

[0075] Based on the difference of step S1, step S2 specifically includes the following steps:

[0076] First, the grayscale brightness at the four corner positions of the first image 31 and the second image 32 at each acquisition position 20 is measured. When the grayscale brightness at the four corner positions of the first image 31 or the second image 32 tends to the maximum grayscale brightness, it is determined that the edge washing is seriously insufficient, and an edge washing insufficient alarm is issued; when the grayscale brightness at at least one corner position of the first image 31 or the second image 32 tends to the minimum grayscale brightness, the subsequent steps are executed.

[0077] Next, calculate and find the position information of the area with the most obvious brightness gradient change in the first image 31 and the second image 32 at each acquisition position 20 (for example, the area with the most obvious brightness gradient change ranked in the top 1%), so as to achieve preliminary locking of the first target area 21 of the first image 31 and the second target area 22 of the second image 32.

[0078] like Figure 3 As shown, then, filtering operations and morphological operations are used to pre-process the first image 31 and the second image 32 at each acquisition position 20 to enhance the image edge information, thereby narrowing and locking the range of the first target area 21 of the first image 31 and the second target area 22 of the second image 32. Figure 3 As shown, taking a second image 32 at a collection position 20 as an example, preprocessing is performed to obtain the range of the second target area 22 of the second image 32 .

[0079] Step S3 specifically includes:

[0080] First, superpixel segmentation is performed on the first image 31 and the second image 32 at each acquisition position 20, and straight line detection is performed on the first image 31 before and after superpixel segmentation to find out all straight lines that may be copper edge positions in the first target area 21, and straight line detection is performed on the second image 32 before and after superpixel segmentation to find out all straight lines that may be crystal edge positions in the second target area 22. The coordinates of all straight lines output in this step are polar coordinates.

[0081] Next, the Hough line detection fusion method is used to merge some of the straight lines before and after the superpixel segmentation in the first target area 21 of the first image 31 at each acquisition position 20, and at the same time, some of the straight lines before and after the superpixel segmentation in the second target area 22 of the second image 32 at each acquisition position 20 are merged.

[0082] Next, the remaining straight lines of the first image 31 at each acquisition position 20 that are located in the first target area 21 before superpixel segmentation are merged with the remaining straight lines of the first image 31 at each acquisition position 20 that are located in the first target area 21 after superpixel segmentation; the remaining straight lines of the second image 32 at each acquisition position 20 that are located in the second target area 22 before superpixel segmentation are merged with the remaining straight lines of the second image 32 at each acquisition position 20 that are located in the second target area 22 after superpixel segmentation.

[0083] Next, the straight lines with the largest number of votes in the first target area 21 and the second target area 22 are respectively selected by probability to lock the straight line where the copper washing edge position and the straight line where the crystal edge position of each of the acquisition positions 20 are located.

[0084] Next, the first image 31 and the second image 32 at each acquisition position 20 are spliced ​​(eg Figure 4 As shown), and in the spliced ​​picture, the distance between the straight line where the copper edge washing position of each acquisition position 20 is located and the straight line where the crystal edge position is located is calculated to obtain the edge washing distance, thereby completing the edge washing distance measurement of each acquisition position 20, and outputting the measurement result.

[0085] Among them, Figure 5 As shown, during the stitching, if there are missing pictures, the missing pictures can be filled in. For example, when the second picture 32 at the third acquisition position 20 is missing, it is necessary to determine whether the second picture 32 at the third acquisition position 20 needs to be filled in, and the picture filling method can be confirmed between step S1 and step S2.

[0086] In summary, the present invention provides a method for calculating the edge washing spacing in copper electroplating, comprising the following steps: providing a wafer that has been processed with copper edge washing, and obtaining an image of at least one acquisition position of the wafer at the crystal edge; pre-processing each of the images according to grayscale brightness to lock a first target area where the copper edge position at each acquisition position is located, and a second target area where the crystal edge position at each acquisition position is located; obtaining a straight line where the copper edge washing position of each acquisition position is located in the first target area through straight line detection, and obtaining a straight line where the crystal edge position of each acquisition position is located in the second target area, and calculating the distance between the straight line where the copper edge washing position of each acquisition position is located and the straight line where the crystal edge position is located, so that the present invention can realize the calculation of the edge washing spacing in copper electroplating without the need for a special optical system device, thereby reducing costs and not affecting measurement results.

[0087] In addition, it should be noted that, unless otherwise specified or indicated, the terms "first" and "second" in the specification are only used to distinguish the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0088] It is to be understood that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for calculating the edge wash spacing in copper electroplating, characterized in that: The following steps are involved: Providing a wafer that has been subjected to copper edge cleaning treatment, and obtaining an image of at least one acquisition position at the wafer edge of the wafer; Preprocessing each of the images according to grayscale brightness to lock a first target area where the copper edge position at each acquisition position is located, and a second target area where the crystal edge position at each acquisition position is located; Performing superpixel segmentation on the image, and performing straight line detection on the image before and after the superpixel segmentation, respectively, to find out all straight lines that may be copper edge positions in the first target area, and all straight lines that may be crystal edge positions in the second target area; The Hough line detection fusion method is used to merge the partial lines before and after the superpixel segmentation in the first target area, and the partial lines before and after the superpixel segmentation in the second target area are merged respectively; Merge the remaining straight lines in the first target area of ​​each image before superpixel segmentation with the remaining straight lines in the first target area after superpixel segmentation, and merge the remaining straight lines in the second target area of ​​each image before superpixel segmentation with the remaining straight lines in the second target area after superpixel segmentation; Select the straight lines with the largest number of votes in the first target area and the second target area by probability, so as to lock the straight line where the copper washing edge position and the straight line where the crystal edge position of each acquisition position are located; The distance between the straight line where the copper washing edge position of each collection position is located and the straight line where the crystal edge position is located is calculated.

2. The method for calculating the edge wash spacing in copper electroplating as claimed in claim 1, characterized in that: Each of the acquisition positions corresponds to a picture, and the picture includes a copper edge position and a crystal edge position.

3. The method for calculating the edge wash spacing in copper electroplating as claimed in claim 2, characterized in that: The specific method of locking the first target area and the second target area is: Measuring the grayscale brightness at four corner positions of the image at each acquisition position, and when the grayscale brightness at at least one corner position of the image approaches the minimum grayscale brightness value, calculating and finding the area with the most obvious brightness gradient change in each image, so as to achieve preliminary locking of the first target area and the second target area; The image at the acquisition position is preprocessed by using filtering operation and morphological operation to lock the range of the first target area and the second target area.

4. The method for calculating the edge wash spacing in copper electroplating as claimed in claim 3, characterized in that: When the grayscale brightness at the four corners of the image all tends to the grayscale brightness maximum value, it is determined that the edge washing is seriously insufficient, and an edge washing insufficient alarm is issued.

5. The method for calculating the edge wash spacing in copper electroplating as claimed in claim 3, characterized in that: The specific method of preprocessing is: The image at the acquisition position is subjected to Gaussian blur processing; Dilate and corrode the image at the acquisition position, so as to expand the contour of the object in each of the images by dilation to obtain a dilated image, and simultaneously shrink the contour of the object in the image by corroding to obtain a corroded image; Subtract the eroded image from the dilated image.

6. The method for calculating the edge wash spacing in copper electroplating as claimed in claim 1, characterized in that: Each of the acquisition positions corresponds to a first picture and a second picture, wherein the first picture includes a copper edge position, and the second picture includes a crystal edge position.

7. The method for calculating the edge wash spacing in copper electroplating as claimed in claim 6, characterized in that: The specific method of locking the first target area and the second target area is: Measuring the grayscale brightness at four corner positions of the first image and the second image at each acquisition position, and when the grayscale brightness at at least one corner position of the first image or the second image approaches the minimum grayscale brightness, calculating and finding the position information of the area with the most obvious brightness gradient change in the first image and the second image at each acquisition position, so as to achieve preliminary locking of the first target area of ​​the first image and the second target area of ​​the second image; The first image and the second image at each acquisition position are preprocessed by using filtering operations and morphological operations to lock the range of the first target area of ​​the first image and the range of the second target area of ​​the second image.

8. The method for calculating the edge wash spacing in copper electroplating as claimed in claim 6, characterized in that: The specific method for obtaining the straight line where the copper washing edge position and the straight line where the crystal edge position of each collection position are located is: Performing superpixel segmentation on the first image and the second image at each acquisition position respectively, and performing straight line detection on the first image before and after the superpixel segmentation to find out all straight lines that may be copper edge positions in the first target area; performing straight line detection on the second image before and after the superpixel segmentation to find out all straight lines that may be crystal edge positions in the second target area; The Hough line detection fusion method is used to merge the partial straight lines before and after the superpixel segmentation in the first target area of ​​the first image at each acquisition position, and the partial straight lines before and after the superpixel segmentation in the second target area of ​​the second image at each acquisition position are merged respectively; Merge the remaining straight lines in the first target area of ​​the first image at each acquisition position before superpixel segmentation with the remaining straight lines in the first target area of ​​the first image at each acquisition position after superpixel segmentation; merge the remaining straight lines in the second target area of ​​the second image at each acquisition position before superpixel segmentation with the remaining straight lines in the second target area of ​​the second image at each acquisition position after superpixel segmentation; The straight lines with the largest number of votes in the first target area and the second target area are respectively selected by probability to lock the straight line where the copper washing edge position and the straight line where the crystal edge position of each acquisition position are located.

9. The method for calculating the edge wash spacing in copper electroplating as claimed in claim 6, characterized in that: Before calculating the distance between the straight line where the copper washing edge position of each acquisition position is located and the straight line where the crystal edge position is located, the method specifically includes: The first image and the second image at each acquisition position are spliced, and the distance between the straight line where the copper edge washing position of each acquisition position is located and the straight line where the crystal edge position is located is calculated in the spliced ​​image to obtain the edge washing distance.

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