Image processing method and device, equipment and storage medium

Abstract

The invention relates to an image processing method, device and equipment and a storage medium, and is applied to the field of wafer defect detection, and the method comprises the following steps: applying to any initial position of the back surface of a collected wafer, and determining an initial focal length sequence of a microscope lens according to the obtained minimum focusing distance of the microscope lens and the allowable height difference of the wafer; obtaining an initial image sequence collected by the microscope lens at the initial position, wherein the initial image sequence is adapted to the initial focal length sequence; performing definition calculation on each image in the initial image sequence based on a preset image definition evaluation algorithm, determining image subsequences according to a preset sequence length, and determining the image subsequence with the highest definition score as an initial target image subsequence; and performing image fusion processing on the images in the initial target image sub-sequence to obtain a target clear image at an initial position. The wafer defect detection method has the technical effects that the wafer image acquisition time and the wafer image fusion processing time are reduced, and the wafer defect detection efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of wafer defect detection, and in particular to an image processing method, device, equipment and storage medium. Background Art

[0002] In the semiconductor wafer manufacturing process, the processing quality of the wafer directly determines the yield and quality of subsequent chip products. The surface of the wafer contains the circuits of the chip, etc. Affected by various factors such as process and raw materials, the surface defects of the wafer are usually very small and have diverse morphological structures. Therefore, it is usually necessary to obtain multiple high-precision and clear wafer images to detect defects on the surface of the wafer. At the same time, during the wafer manufacturing process, there may also be scratches, corrosion and other defects on the back of the wafer. Scratches, corrosion and other defects on the back may cause cracks in the chip. Therefore, the defects on the back of the wafer are detected to ensure the quality of the wafer and improve the wafer yield.

[0003] Defect detection on the back side of the wafer is performed based on the collected wafer images. Due to the non-absolute flatness of the back side of the wafer, that is, the height difference of the wafer, in order to obtain a clear image, it is necessary to shoot the wafer at different focal lengths and perform image fusion to obtain a clear image and improve image quality, thereby increasing the defect detection rate; however, the structure of the back side of the wafer is relatively simple, and image fusion of all collected images will result in a large amount of image data to be processed and a long time to process the image, which in turn leads to a decrease in the efficiency of wafer defect detection. Summary of the invention

[0004] In order to help solve the problem that the structure on the back side of the wafer is relatively simple, image fusion of all collected images will result in a large amount of processed image data, a long image processing time, and thus reduce the efficiency of wafer defect detection, the present application provides an image processing method, device, equipment and storage medium.

[0005] In a first aspect, the present application provides an image processing method, which adopts the following technical solution: the method is applied to an automatic optical detection system for defects on the back side of a wafer, the automatic optical detection system for defects on the back side of a wafer comprises a microscope lens, the microscope lens is used to collect an image of the back side of the wafer, and the focal length of the microscope lens is adjustable, and the method comprises:

[0006] Applied to any starting position on the back of the collected wafer, the starting focal length sequence of the microscope lens is determined according to the acquired minimum focusing distance of the microscope lens and the acceptable height difference of the wafer;

[0007] Acquire a starting image sequence collected by the microscope lens at the starting position, wherein the starting image sequence is adapted to the starting focal length sequence;

[0008] Calculating the clarity of each image in the starting image sequence based on a preset image clarity evaluation algorithm, determining an image subsequence according to a preset sequence length, and determining the image subsequence with the highest clarity score as the starting target image subsequence;

[0009] The images in the starting target image subsequence are subjected to image fusion processing to obtain a clear target image at the starting position.

[0010] In a specific possible implementation manner, after performing image fusion processing on the images in the starting target image subsequence to obtain the target clear image at the starting position, the method further includes:

[0011] Applied to any non-starting position on the back of the captured wafer, the target focal length at the current position is determined based on the target image subsequence at the previous position;

[0012] Acquire a first image captured by the microscope lens at the current position, wherein the first image is adapted to the target focal length;

[0013] The clarity of the first image is calculated based on a preset image clarity evaluation algorithm to determine whether the clarity of the first image is within a first preset threshold range, and the target clear image at the current position is determined according to the determination result.

[0014] In a specific implementation manner, determining the clear target image at the current position according to the judgment result includes:

[0015] If the clarity value of the first image is within a first preset threshold range, determining that the first image is the target clear image at the current position;

[0016] If the clarity value of the first image is not within the first preset threshold range, an initial focal length subsequence of the current position is determined according to the target focal length of the current position, and a target clear image of the current position is determined according to the initial focal length subsequence of the current position.

[0017] In a specific possible implementation manner, determining the target clear image at the current position according to the initial focal length subsequence at the current position comprises:

[0018] Acquire an initial image subsequence collected by the microscope lens at the current position, wherein the initial image subsequence is adapted to an initial focal length subsequence at the current position;

[0019] Calculating the clarity of each image in the initial image subsequence based on a preset image clarity evaluation algorithm, and if the clarity value of each image is within a second preset threshold range, determining that the initial image subsequence is the target image subsequence at the current position;

[0020] The images in the target image subsequence are subjected to image fusion processing to obtain a clear target image at the current position.

[0021] In a specific implementation manner, before performing image fusion processing on the images in the target image subsequence to obtain the target clear image at the current position, the method further includes:

[0022] If the clarity value of each image is not within the second preset threshold range, adjusting the initial focus subsequence of the current position according to the image clarity calculation result and the minimum focus distance of the microscope lens to generate an adjusted focus subsequence of the current position;

[0023] An adjusted image subsequence corresponding to the adjusted focus subsequence of the current position is obtained, and it is re-determined whether the clarity value of each image in the adjusted image subsequence is within a second preset threshold range; if the clarity value of each image in the adjusted image subsequence is within the second preset threshold range, the adjusted image subsequence is determined to be the target image subsequence of the current position.

[0024] In a specific possible implementation manner, determining the target focal length at the current position according to the target image subsequence at the previous position includes:

[0025] Calculating the clarity of each image in the target image subsequence at the previous position according to a preset image clarity evaluation algorithm, and determining the focal length corresponding to the image with the highest clarity;

[0026] The height difference between the current position and the previous position is calculated, and the target focal length of the current position is determined according to the height difference and the focal length corresponding to the image with the highest definition at the previous position.

[0027] In a specific implementation manner, the preset sequence length is at least 2.

[0028] In a second aspect, the present application provides an image processing device, which adopts the following technical solution: the device is applied to an automatic optical detection system for defects on the back side of a wafer, the automatic optical detection system for defects on the back side of a wafer comprises a microscope lens, the microscope lens is used to collect an image of the back side of the wafer, the focal length of the microscope lens is adjustable, and the device comprises:

[0029] A starting sequence determination module is used to be applied to any starting position on the back side of the collected wafer, and to determine the starting focal length sequence of the microscope lens according to the acquired minimum focusing distance of the microscope lens and the acceptable height difference of the wafer;

[0030] A starting image acquisition module, used for acquiring a starting image sequence collected by the microscope lens at the starting position, wherein the starting image sequence is adapted to the starting focal length sequence;

[0031] a target image determination module, configured to calculate the clarity of each image in the starting image sequence based on a preset image clarity evaluation algorithm, determine an image subsequence according to a preset sequence length, and determine the image subsequence with the highest clarity score as the starting target image subsequence;

[0032] The clear image generation module is used to perform image fusion processing on the images in the starting target image subsequence to obtain the target clear image at the starting position.

[0033] In a third aspect, the present application provides a computer device, which adopts the following technical solution: it includes a memory and a processor, and the memory stores a computer program that can be loaded by the processor and execute any one of the above-mentioned image processing methods.

[0034] In a fourth aspect, the present application provides a computer-readable storage medium, which adopts the following technical solution: storing a computer program that can be loaded by a processor and execute any of the above-mentioned image processing methods.

[0035] In summary, this application has the following beneficial technical effects:

[0036] After acquiring the maximum number of wafer back side images, a starting target image subsequence with higher clarity is determined based on the image clarity. The number of starting target image subsequences can be determined by the user, thereby reducing the number of image fusions and the acquisition time of wafer inspection images. At the same time, it can save the processing time of wafer image fusion, thereby improving the efficiency of wafer image fusion and wafer defect detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of an image processing method in an embodiment of the present application;

[0038] Figure 2 is a schematic diagram of an image processing device in an embodiment of the present application;

[0039] Figure 3 It is a schematic diagram used to embody a computer device in an embodiment of the present application.

[0040] Reference numerals: 201, starting sequence determination module; 202, starting image acquisition module; 203, target image determination module; 204, clear image generation module. DETAILED DESCRIPTION

[0041] The following combination Figure 1-Figure 3 This application is described in further detail.

[0042] The embodiment of the present application discloses an image processing method, which is applied to an automatic optical detection system for defects on the back of a wafer. The image processing method can reduce the number of images during image fusion, thereby saving the processing time of wafer image fusion, and can improve the quality of wafer images after fusion and the efficiency of wafer defect detection. In the semiconductor wafer manufacturing process, the processing quality of the wafer directly determines the yield and quality of subsequent chip products. The wafer surface contains the circuits of the chip, etc. Affected by various factors such as process and raw materials, the surface defects of the wafer are usually very small and have diverse morphological structures. Therefore, the surface defects of the wafer usually require the acquisition of multiple high-precision and clear wafer images to detect the defects on the surface of the wafer. At the same time, during the wafer manufacturing process, there may also be defects such as scratches and corrosion on the back of the wafer. The scratches and corrosion on the back may cause cracks in the chip. Therefore, the defects on the back of the wafer are detected to ensure the quality of the wafer and improve the wafer yield.

[0043] The defect detection on the back of the wafer is performed based on the collected wafer image. Due to the non-absolute flatness of the back of the wafer, that is, the height difference of the wafer, in order to obtain a clear image, it is necessary to shoot the wafer at different focal lengths and perform image fusion to obtain a clear image and improve the image quality, thereby improving the defect detection rate; however, the structure of the back of the wafer is relatively simple, and image fusion of all collected images will result in a large amount of processed image data and a long image processing time, which will lead to a decrease in the efficiency of wafer defect detection. In order to help improve the clarity of wafer fusion images and the efficiency of wafer defect detection, the present application provides an image processing method.

[0044] Reference Figure 1 , the method comprises the following steps:

[0045] S10, applied to any starting position on the back side of the wafer to be collected, determines the starting focal length sequence of the microscope lens according to the acquired minimum focusing distance of the microscope lens and the acceptable height difference of the wafer.

[0046] Specifically, the wafer image processing method is applied to the automatic optical inspection system of wafer back defects. The image processing method is implemented based on a liquid microscope lens. The liquid microscope lens has a minimum focusing distance, and the user can set the minimum focusing distance of the liquid microscope lens in advance. At any starting position on the back of the captured wafer, the system determines the starting focal length sequence of the microscope lens based on the minimum focusing distance of the microscope lens and the acceptable height difference of the wafer.

[0047] It should be noted that the number of images of the back of the wafer acquired according to the minimum focusing distance of the microscope lens is the maximum number of images; in addition, the number of wafer images acquired is related to the acceptable height difference of the wafer, and the acceptable height difference of the wafer is related to the warping amplitude of the wafer. During the wafer manufacturing process, the wafer may have a certain warping amplitude. Generally, the warping amplitude of the wafer is ±5mm, and the acceptable height difference of the wafer is 10mm. At this time, the number of starting focal length sequences of the microscope lens is 10mm divided by the minimum focusing distance of the microscope lens. Assuming that the minimum focusing distance of the microscope lens is 0.4mm, there are 25 continuous focal lengths in the final starting focal length sequence.

[0048] S20, acquiring a starting image sequence collected by the microscope lens at a starting position, wherein the starting image sequence is adapted to a starting focal length sequence.

[0049] Specifically, the corresponding starting image sequence is acquired according to the determined starting focal length sequence. For example, assuming that the minimum focusing distance of the microscope lens is 0.4mm and the wafer warpage amplitude is ±5mm, the acceptable height difference of the wafer is 10mm. The final determined starting focal length sequence has a total of 25 continuous focal lengths. The microscope lens acquires the corresponding starting image sequence according to the determined 25 focal length sequences.

[0050] S30, calculating the clarity of each image in the starting image sequence based on a preset image clarity evaluation algorithm, determining an image subsequence according to a preset sequence length, and determining the image subsequence with the highest clarity score as the starting target image subsequence.

[0051] Specifically, the clarity of each image in the starting image sequence is calculated based on a preset image clarity evaluation algorithm, wherein the image clarity evaluation algorithm can directly use an existing algorithm to evaluate the clarity of each image and give a corresponding score. Afterwards, the image subsequence is determined according to the preset sequence length. For example, if the image sequence length is set to 5, then 5 continuous images need to be screened out from the image subsequence. The screening method can be to sort the image sequence according to clarity and determine the image subsequence with the highest clarity score as the starting target image subsequence. Considering that there are blurred and clear images in the maximum number of collected starting image sequences, and in the image fusion process, blurred images cannot improve the clarity of the fused image, and at the same time, may increase the image fusion processing time, thereby reducing the efficiency of image fusion. Therefore, the starting target image subsequence is determined according to the clarity sorting, which reduces the number of images, thereby saving the processing time of image fusion, and improving the efficiency of image fusion, thereby improving the efficiency of wafer inspection.

[0052] It should be noted that in the embodiment of the present application, the preset sequence length, that is, the number of the starting target image subsequences, is at least 2. During the wafer manufacturing process, the wafer is not absolutely flat and may have a certain warping amplitude. Considering the warping amplitude of the wafer, the number of continuous clear images is determined to be at least 2 to ensure that a clear image can be captured at a detection point with a slope for defect detection, thereby improving the defect detection rate.

[0053] S40, performing image fusion processing on the images in the starting target image subsequence to obtain a clear target image at the starting position.

[0054] Specifically, each image in the determined starting target image subsequence is image fused to generate a final target clear image at the starting position. Considering that there are also clear images and blurred images in each image in the determined starting target image subsequence, the clear parts of multiple images are fused by image fusion to generate a wafer fusion image with higher clarity to obtain the final target clear image, which improves the image quality and helps to perform wafer defect detection based on the clear image later.

[0055] In the present application scheme, after acquiring a maximum number of wafer back side images, a starting target image subsequence with higher clarity is determined based on the image clarity. The number of starting target image subsequences can be determined by the user, thereby reducing the number of image fusions and reducing the acquisition time of wafer inspection images. At the same time, it can save the processing time of wafer image fusion, thereby improving the efficiency of wafer image fusion and wafer defect detection.

[0056] In one embodiment, after performing image fusion processing on the images in the starting target image subsequence to obtain a clear target image at the starting position, the following steps may be performed:

[0057] Wafer back defect detection is a continuous process. After determining the starting position of wafer back defect detection, there are several non-starting positions to be detected. Therefore, for any non-starting position on the back of the captured wafer, the target focal length of the current position is determined based on the target image subsequence of the previous position; specifically, the clarity of each image in the target image subsequence of the previous position is calculated according to the preset image clarity evaluation algorithm, and the focal length corresponding to the image with the highest clarity is determined; the height difference between the current position and the previous position is calculated, and the target focal length of the current position is determined based on the height difference and the focal length corresponding to the image with the highest clarity at the previous position. For example, assuming that the current position is a non-starting position immediately following the starting position, the previous position of the current position can be understood as the starting position, and then the target focal length of the current position is determined according to the starting target image subsequence obtained at the starting position; the determination method can be to first calculate the clarity of each image in the starting target image subsequence through a clarity evaluation algorithm, and determine the focal length corresponding to the image with the highest clarity, and then calculate the height difference between the current position and the starting position, and on the basis of the focal length corresponding to the determined image with the highest clarity, adjust the focal length according to the height difference to obtain the target focal length of the current position.

[0058] After determining the target focal length of the current position, the first image captured by the microscope lens at the current position is acquired according to the determined target focal length. Finally, the clarity of the first image is calculated based on a preset image clarity evaluation algorithm to determine whether the clarity of the first image is within a first preset threshold range, and the target clear image of the current position is determined according to the judgment result.

[0059] If the clarity value of the first image is within the first preset threshold range, the first image is determined to be the target clear image of the current position; if the clarity value of the first image is not within the first preset threshold range, the initial focal length subsequence of the current position is determined according to the target focal length of the current position, and the target clear image of the current position is determined according to the initial focal length subsequence of the current position. Specifically, according to the clarity evaluation algorithm, it is determined whether the clarity of the acquired first image is within the preset threshold range. If it is within the threshold range, it means that the first image is a clear image, and the acquired first image can be directly set as the target clear image. If the image clarity meets the threshold, there is no need to acquire more images for image fusion, thereby saving image fusion time and improving image fusion efficiency; if it is not within the threshold range, it is necessary to acquire an image sequence of a preset sequence length according to the target focal length of the current position for image fusion to obtain a higher clarity image of the back side of the wafer.

[0060] When the clarity of the first image is not within the threshold range, the step of acquiring an image sequence of a preset sequence length according to the target focal length of the current position for image fusion can be performed as follows: first, determining an initial focal length subsequence of the current position according to the determined target focal length, and the determination method can be selected by selecting according to the minimum focusing distance of the microscope lens near the target focal length, for example, selecting the target focal length and a continuous focal length sequence of the target focal length±the minimum focusing distance to obtain an initial focal length subsequence of a preset length, and the preset length is set to at least 2; after determining the initial focal length subsequence, acquiring an initial image subsequence collected by the microscope lens at the current position, the initial image subsequence being adapted to the initial focal length subsequence of the current position, wherein the length of the acquired initial image subsequence is a preset length, which is consistent with the number of the starting target image subsequences acquired in the above-mentioned starting position scenario, and in the embodiment of the present application, the length is at least 2. Afterwards, the clarity of each image in the initial image subsequence is calculated based on a preset image clarity evaluation algorithm, and the clarity of each image is compared with a preset clarity threshold. If the clarity value of each image is within a second preset threshold range, the initial image subsequence is determined to be the target image subsequence at the current position; the images in the target image subsequence are subjected to image fusion processing to obtain a target clear image at the current position.

[0061] In the present application scheme, a clear image of the back side of the wafer at the current position is obtained based on a clear image subsequence obtained at the previous position and the height difference between the current position and the previous position. A target image subsequence of a preset length with higher clarity that has been obtained at the previous position may have a height difference at the current position, but the height difference between the two positions is generally very small. Therefore, the target image subsequence at the current position can be obtained by fine-tuning the focal length based on the sequence images obtained at the previous position, thereby saving the time for acquiring images and the time for calculating image clarity, thereby improving the efficiency of the image fusion process and obtaining a higher-definition image of the back side of the wafer.

[0062] In one embodiment, considering that the initial image subsequence collected by the microscope lens at the current position may have partially blurred images, low definition, and does not meet the second preset threshold range, therefore, before performing image fusion processing on the images in the target image subsequence to obtain a clear target image at the current position, the following steps may be further performed:

[0063] If the clarity value of each image is not within the second preset threshold range, that is, there is at least one image whose clarity is not within the second preset threshold range, then according to the image clarity calculation result and the minimum focusing distance of the microscope lens, the initial focus subsequence of the current position is adjusted to generate the adjustment focus subsequence of the current position. It can also be understood that according to the image clarity calculation result, on the basis of the current initial focus subsequence, the minimum focusing distance of the microscope lens is adjusted up or down to generate a new adjustment focus subsequence. Afterwards, the adjustment image subsequence corresponding to the adjustment focus subsequence of the current position is obtained, and it is re-determined whether the clarity values ​​of each image in the adjustment image subsequence are all within the second preset threshold range. If the clarity values ​​of each image in the adjustment image subsequence are all within the second preset threshold range, the adjustment image subsequence is determined to be the target image subsequence of the current position.

[0064] In the present application scheme, considering that the initial image subsequence collected by the microscope lens at the current position may have partially blurred images, low clarity, and does not meet the second preset threshold range, fine-tuning is performed on the basis of the original acquired initial focal length subsequence to obtain an adjusted focal length subsequence, and the corresponding target image subsequence is obtained according to the adjusted focal length subsequence, thereby ensuring the clarity of the acquired image and further improving the quality of the fused image.

[0065] Figure 1 FIG. 1 is a flow chart of an image processing method in one embodiment. It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but the steps are not necessarily executed in the order indicated by the arrows; unless otherwise specified in this document, there is no strict order restriction for the execution of the steps, and the steps may be executed in other orders; and Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0066] Based on the above method, an embodiment of the present application also discloses an image processing device.

[0067] Reference Figure 2 , the device includes the following modules:

[0068] The starting sequence determination module 201 is used to be applied to any starting position on the back side of the collected wafer, and determine the starting focal length sequence of the microscope lens according to the acquired minimum focusing distance of the microscope lens and the acceptable height difference of the wafer;

[0069] A starting image acquisition module 202 is used to acquire a starting image sequence collected by the microscope lens at a starting position, wherein the starting image sequence is adapted to a starting focal length sequence;

[0070] The target image determination module 203 is used to calculate the clarity of each image in the starting image sequence based on a preset image clarity evaluation algorithm, determine an image subsequence according to a preset sequence length, and determine the image subsequence with the highest clarity score as the starting target image subsequence;

[0071] The clear image generation module 204 is used to perform image fusion processing on the images in the starting target image subsequence to obtain a target clear image at the starting position.

[0072] In one embodiment, the clear image generation module 204 is also used to be applied to any non-starting position on the back side of the captured wafer, and determine the target focal length of the current position according to the target image subsequence of the previous position; obtain the first image captured by the microscope lens at the current position, wherein the first image is adapted to the target focal length; calculate the clarity of the first image based on a preset image clarity evaluation algorithm, determine whether the clarity of the first image is within a first preset threshold range, and determine the target clear image of the current position according to the determination result.

[0073] In one embodiment, the clear image generation module 204 is further configured to determine that the first image is a target clear image at the current position if the clarity value of the first image is within a first preset threshold range; if the clarity value of the first image is not within the first preset threshold range, determine the initial focal length subsequence of the current position according to the target focal length of the current position, and

[0074] In one embodiment, the clear image generation module 204 is also used to obtain an initial image subsequence collected by the microscope lens at the current position, wherein the initial image subsequence is adapted to the initial focal length subsequence at the current position; based on a preset image clarity evaluation algorithm, the clarity of each image in the initial image subsequence is calculated, and if the clarity value of each image is within a second preset threshold range, the initial image subsequence is determined to be a target image subsequence at the current position; and the images in the target image subsequence are subjected to image fusion processing to obtain a target clear image at the current position.

[0075] In one embodiment, the clear image generation module 204 is further used to adjust the initial focus subsequence of the current position according to the image clarity calculation result and the minimum focusing distance of the microscope lens to generate an adjusted focus subsequence of the current position if the clarity value of each image is not within the second preset threshold range; obtain an adjusted image subsequence corresponding to the adjusted focus subsequence of the current position, and re-judge whether the clarity value of each image in the adjusted image subsequence is within the second preset threshold range; if the clarity value of each image in the adjusted image subsequence is within the second preset threshold range, determine that the adjusted image subsequence is the target image subsequence of the current position.

[0076] In one embodiment, the clear image generation module 204 is further used to calculate the clarity of each image in the target image subsequence of the previous position according to a preset image clarity evaluation algorithm, and determine the focal length corresponding to the image with the highest clarity; calculate the height difference between the current position and the previous position, and determine the target focal length of the current position according to the height difference and the focal length corresponding to the image with the highest clarity at the previous position.

[0077] In one embodiment, the preset sequence length in the target image determination module 203 is at least 2.

[0078] The image processing device provided in the embodiment of the present application can be applied to the image processing method provided in the above embodiment. For relevant details, refer to the above method embodiment. The implementation principle and technical effect are similar and will not be repeated here.

[0079] It should be noted that: when the image processing device provided in the embodiment of the present application performs image processing, only the division of the above-mentioned functional modules / functional units is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules / functional units as needed, that is, the internal structure of the image processing device is divided into different functional modules / functional units to complete all or part of the functions described above. In addition, the implementation method of the image processing method provided in the above method embodiment and the implementation method of the image processing device provided in this embodiment belong to the same concept. The specific implementation process of the image processing device provided in this embodiment is detailed in the above method embodiment, which will not be repeated here.

[0080] The embodiment of the present application also discloses a computer device.

[0081] Specifically, if Figure 3As shown, the computer device can be a computer device such as a desktop computer, a laptop computer, a PDA, and a cloud server. The computer device may include, but is not limited to, a processor and a memory. The processor and the memory may be connected via a bus or otherwise. The processor may be a central processing unit (CPU). The processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, graphics processors (GPU), embedded neural network processors (NPU) or other dedicated deep learning coprocessors, discrete gates or transistor logic devices, discrete hardware components and other chips, or a combination of the above-mentioned various chips.

[0082] As a non-transient computer-readable storage medium, the memory can be used to store non-transient software programs, non-transient computer executable programs and modules, such as program instructions / modules corresponding to the methods in the above-mentioned embodiments of the present application. The processor executes various functional applications and data processing of the processor by running the non-transient software programs, instructions and modules stored in the memory, that is, the method in the above-mentioned method implementation is realized. The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created by the processor, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network and a combination thereof.

[0083] The embodiment of the present application also discloses a computer-readable storage medium.

[0084] Specifically, a computer-readable storage medium is used to store a computer program, and when the computer program is executed by a processor, the method in the above-mentioned method implementation is implemented. Those skilled in the art will understand that the implementation of all or part of the process in the above-mentioned implementation method of the present application can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and the program, when executed, may include the process of the implementation of the above-mentioned methods. Among them, the storage medium may be a disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory (Flash Memory), a hard disk (Hard Disk Drive, abbreviated as: HDD) or a solid-state drive (SSD), etc.; the storage medium may also include a combination of the above-mentioned types of memory.

[0085] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. An image processing method, characterized in that: The method is applied to an automatic optical detection system for wafer backside defects, wherein the automatic optical detection system for wafer backside defects comprises a microscope lens, wherein the microscope lens is used to collect an image of the backside of the wafer, and wherein the focal length of the microscope lens is adjustable. The method comprises: Applied to any starting position on the back of the collected wafer, the starting focal length sequence of the microscope lens is determined according to the acquired minimum focusing distance of the microscope lens and the acceptable height difference of the wafer; Acquire a starting image sequence collected by the microscope lens at the starting position, wherein the starting image sequence is adapted to the starting focal length sequence; Calculating the clarity of each image in the starting image sequence based on a preset image clarity evaluation algorithm, determining an image subsequence according to a preset sequence length, and determining the image subsequence with the highest clarity score as the starting target image subsequence; The images in the starting target image subsequence are subjected to image fusion processing to obtain a clear target image at the starting position.

2. The method according to claim 1, characterized in that: After performing image fusion processing on the images in the starting target image subsequence to obtain the target clear image at the starting position, the method further includes: Applied to any non-starting position on the back of the captured wafer, the target focal length at the current position is determined based on the target image subsequence at the previous position; Acquire a first image captured by the microscope lens at the current position, wherein the first image is adapted to the target focal length; The clarity of the first image is calculated based on a preset image clarity evaluation algorithm to determine whether the clarity of the first image is within a first preset threshold range, and the target clear image at the current position is determined according to the determination result.

3. The method according to claim 2, characterized in that: Determining the clear target image at the current position according to the judgment result includes: If the clarity value of the first image is within a first preset threshold range, determining that the first image is a target clear image at the current position; If the clarity value of the first image is not within the first preset threshold range, an initial focal length subsequence of the current position is determined according to the target focal length of the current position, and a target clear image of the current position is determined according to the initial focal length subsequence of the current position.

4. The method according to claim 3, characterized in that: Determining the target clear image at the current position according to the initial focal length subsequence at the current position includes: Acquire an initial image subsequence collected by the microscope lens at the current position, wherein the initial image subsequence is adapted to an initial focal length subsequence at the current position; Calculating the clarity of each image in the initial image subsequence based on a preset image clarity evaluation algorithm, and if the clarity value of each image is within a second preset threshold range, determining that the initial image subsequence is the target image subsequence at the current position; The images in the target image subsequence are subjected to image fusion processing to obtain a clear target image at the current position.

5. The method according to claim 4, characterized in that: Before performing image fusion processing on the images in the target image subsequence to obtain the target clear image at the current position, the method further includes: If the clarity value of each image is not within the second preset threshold range, adjusting the initial focus subsequence of the current position according to the image clarity calculation result and the minimum focus distance of the microscope lens to generate an adjusted focus subsequence of the current position; An adjusted image subsequence corresponding to the adjusted focus subsequence of the current position is obtained, and it is re-determined whether the clarity value of each image in the adjusted image subsequence is within a second preset threshold range; if the clarity value of each image in the adjusted image subsequence is within the second preset threshold range, the adjusted image subsequence is determined to be the target image subsequence of the current position.

6. The method according to claim 2, characterized in that: Determining the target focal length at the current position according to the target image subsequence at the previous position includes: Calculating the clarity of each image in the target image subsequence at the previous position according to a preset image clarity evaluation algorithm, and determining the focal length corresponding to the image with the highest clarity; The height difference between the current position and the previous position is calculated, and the target focal length of the current position is determined according to the height difference and the focal length corresponding to the image with the highest definition at the previous position.

7. The method according to claim 1, characterized in that: The preset sequence length is at least 2.

8. An image processing device, characterized in that: The device is applied to an automatic optical detection system for defects on the back side of a wafer. The automatic optical detection system for defects on the back side of a wafer comprises a microscope lens, which is used to collect an image of the back side of the wafer. The focal length of the microscope lens is adjustable. The device comprises: A starting sequence determination module (201) is used to be applied to any starting position on the back side of the collected wafer, and to determine the starting focal length sequence of the microscope lens according to the acquired minimum focusing distance of the microscope lens and the acceptable height difference of the wafer; A starting image acquisition module (202) is used to acquire a starting image sequence collected by the microscope lens at the starting position, wherein the starting image sequence is compatible with the starting focal length sequence; A target image determination module (203) is used to calculate the clarity of each image in the starting image sequence based on a preset image clarity evaluation algorithm, determine an image subsequence according to a preset sequence length, and determine the image subsequence with the highest clarity score as the starting target image subsequence; The clear image generation module (204) is used to perform image fusion processing on the images in the starting target image subsequence to obtain the target clear image at the starting position.

9. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program which can be loaded by the processor and executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: A computer program is stored which can be loaded by a processor and execute the method according to any one of claims 1 to 7.

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