Wafer warpage detection method, device, equipment and medium

Abstract

The application provides a wafer warping detection method, device, equipment and medium, comprising: acquiring a circumferential surface image of a reference wafer, performing image processing on the circumferential surface image of the reference wafer to obtain a reference wafer edge image and reference coordinate information of reference wafer edge sampling points; acquiring a circumferential surface image of a wafer to be detected, performing image processing on the circumferential surface image of the wafer to be detected to obtain a wafer-to-be-detected edge image and detection coordinate information of wafer-to-be-detected edge sampling points; obtaining deviation information of the edge sampling points according to the detection coordinate information and the reference coordinate information; calculating a discrete Fourier series of the edge sampling points according to the deviation information of the edge sampling points; and determining a warping type and a warping degree according to the discrete Fourier series of the edge sampling points. The application does not have to rely on special equipment for separate detection, and wafer warping detection can be performed at the same time as other wafer detection items, thereby reducing wafer warping detection costs and improving detection efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing and detection, and in particular to a wafer warpage detection method, device, equipment and medium. Background Art

[0002] In the semiconductor industry, warpage is a common phenomenon and a key indicator in the wafer manufacturing process. It manifests itself as a radial curvature of the wafer, typically forming a saddle or bowl shape. Wafer warpage has multiple causes, primarily due to differences in the physical properties of the various material layers and coating uniformity, which leads to significant stress accumulation within the wafer and, in turn, macroscopic deformation. Defects, process technology, and environmental factors can also contribute to wafer warpage.

[0003] Warpage can severely impact wafer production and quality. First, processes like photolithography require extremely precise positioning and alignment, and warpage can affect the wafer's surface flatness and device placement, leading to increased process errors or even inability to proceed. Furthermore, wafer warpage can directly impact device performance and stability, leading to subsequent defects or even unusability. Finally, warpage can affect the wafer's mechanical stability, causing insufficient strength or even breakage. Warpage increases with wafer size, making warpage detection crucial during manufacturing to control it.

[0004] Current wafer warpage detection methods utilize optical, acoustic, or mechanical methods and specialized equipment to scan the wafer surface individually to obtain complete wafer morphology information. However, this warpage detection method is limited in purpose and relatively expensive. Therefore, it is necessary to propose a wafer warpage detection method, apparatus, device, and medium to address the aforementioned issues. Summary of the Invention

[0005] The object of the present invention is to provide a wafer warpage detection method, device, equipment and medium to improve the problems of existing warpage detection methods such as single use and high cost.

[0006] In a first aspect, the wafer warpage detection method provided by the present invention includes: obtaining a circumferential side image of a reference wafer, performing image processing on the circumferential side image of the reference wafer to obtain a reference wafer edge image and reference coordinate information of edge sampling points in the reference wafer edge image; obtaining a circumferential side image of a wafer to be detected, performing image processing on the circumferential side image of the wafer to be detected to obtain a reference wafer edge image and detection coordinate information of edge sampling points in the reference wafer edge image; obtaining deviation information of the edge sampling points based on the detection coordinate information and the reference coordinate information; calculating the discrete Fourier series of the edge sampling points based on the deviation information of the edge sampling points; and determining the warpage type and warpage degree based on the discrete Fourier series of the edge sampling points.

[0007] The method provided by the present invention has the beneficial effect of processing the circumferential side images of the reference wafer and the circumferential side images of the wafer to be inspected to extract reference coordinate information and inspection coordinate information, thereby calculating the deviation information of the edge sampling points, and calculating the discrete Fourier series of the edge sampling points to determine the warpage type and warpage degree of the wafer to be inspected. The present invention can complete the warpage detection of the wafer by processing and calculating the images, eliminating the need for separate inspection with dedicated equipment. Wafer warpage detection can be performed simultaneously with other wafer inspection items, thereby reducing the cost of wafer warpage detection and improving detection efficiency.

[0008] In a possible embodiment, the discrete Fourier series satisfies the following formula:

[0009]

[0010] Among them, c n are the Fourier coefficients, p[k] represents the vertical coordinate deviation value of the kth edge sampling point, N represents the total number of discrete edge sampling points, n is the number of terms in the discrete Fourier series, e is the natural exponent, i is the imaginary unit, ω is the fundamental frequency,

[0011] In a possible embodiment, determining the warping type and warping degree according to the discrete Fourier series of the edge sampling points includes:

[0012] Calculating the amplitude and phase of the first and third terms of the discrete Fourier series of the edge sampling point to determine the warpage type of the wafer to be inspected;

[0013] The first several spatial functions of the discrete Fourier series of the edge sampling points are superimposed to calculate the warpage of the wafer to be inspected.

[0014] In a possible embodiment, calculating the amplitude and phase of the first and third terms of the discrete Fourier series of the edge sampling point to determine the warpage type of the wafer to be inspected includes:

[0015] If the amplitude A0 of the first term of the discrete Fourier series is the largest, it is determined that the wafer to be inspected is bowl-shaped. If the phase of the first term of the discrete Fourier series is is 0, the bowl is facing upwards, if the phase of the first term of the discrete Fourier series If it is π, the bowl mouth faces downwards;

[0016] If the amplitude A2 of the third term of the discrete Fourier series is the largest, it is determined that the wafer to be inspected is saddle-shaped.

[0017] In a possible embodiment, the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points are superimposed to calculate the warpage of the wafer to be detected, comprising:

[0018] According to the discrete Fourier series components of the edge sampling points k=0, 1, 2,..., N-1, the spatial functions z of at least the first three terms of the discrete Fourier series of the edge sampling points are calculated by using the following formula k and superimposed:

[0019]

[0020]

[0021] wherein, α is a parameter, ρ is an extreme value, θ is an extreme angle, A k represents the amplitude of the kth component, ω k represents the frequency of the kth component, represents the phase of the kth component.

[0022] When ρ=1, θ∈[0, 2π), z=f(1, θ), the warpage of the wafer to be detected is equal to the difference between the maximum value and the minimum value of z=f(1, θ).

[0023] In a possible embodiment, after the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points are superimposed, the method further comprises: superimposing the waveform diagrams of the spatial functions of at least the first three terms of the discrete Fourier series of the edge sampling points to obtain a shape simulation diagram of the wafer to be detected.

[0024] In a second aspect, the present application further provides a wafer warpage detection device, which comprises a module / unit for executing the method of any one of the possible designs of the first aspect. These modules / units can be implemented by hardware, or implemented by hardware executing corresponding software.

[0025] In a third aspect, the embodiments of the present application provide an electronic device, comprising a processor and a memory. The memory is configured to store one or more computer programs. When the one or more computer programs stored in the memory are executed by the processor, the electronic device is enabled to implement the method of any one of the possible designs of the first aspect.

[0026] In a fourth aspect, the embodiments of the present application further provide a computer readable storage medium, which comprises a computer program. When the computer program is run on an electronic device, the electronic device is enabled to execute the method of any one of the possible designs of any one of the aspects.

[0027] In a fifth aspect, the embodiments of the present application further provide a computer program product comprising the computer program product, when the computer program product is run on an electronic device, causes the electronic device to execute the method of any possible design of any one of the above aspects.

[0028] The beneficial effects of the above-mentioned second to fifth aspects can be referred to the description in the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A flowchart of the wafer warping detection method of the present application;

[0030] Figure 2 A schematic diagram of the wafer warping detection method in a specific embodiment of the present application;

[0031] Figure 3 A waveform diagram corresponding to the spatial function of the first six components of the discrete Fourier series in a specific embodiment of the wafer warping detection method of the present application;

[0032] Figure 4 A schematic diagram of the wafer warping detection device of the present application;

[0033] Figure 5 A structural schematic diagram of the electronic device of the present application. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the common meanings thereof by those of ordinary skill in the art to which the present application belongs. The terms such as “comprise” and the like used herein are intended to cover the elements or objects recited before the terms and the like listed after the terms, and equivalents thereof, without excluding other elements or objects.

[0035] In view of the problems in the prior art, the embodiments of the present application provide a wafer warping detection method, referring to Figure 1 The method comprises:

[0036] S101: Obtain a peripheral surface image of a reference wafer, and perform image processing on the peripheral surface image of the reference wafer to obtain a reference wafer edge image and reference coordinate information of edge sampling points in the reference wafer edge image.

[0037] S102: Acquire a circumferential side image of the wafer 201 to be inspected, and perform image processing on the circumferential side image of the wafer 201 to be inspected to obtain an edge image of the wafer 201 to be inspected and detection coordinate information of edge sampling points in the edge image of the wafer 201 to be inspected.

[0038] S103: Obtaining deviation information of edge sampling points based on the detected coordinate information and the reference coordinate information. Specifically, calculating the difference between the detected coordinate information and the corresponding reference coordinate information to obtain the deviation information of the edge sampling points.

[0039] S104: Calculate the discrete Fourier series of the edge sampling point according to the deviation information of the edge sampling point. The discrete Fourier series satisfies the following formula: k=0,1,2,...,N-1; where c n are the Fourier coefficients, p[k] represents the vertical coordinate deviation value of the kth edge sampling point, N represents the total number of discrete edge sampling points, n is the number of terms in the discrete Fourier series, e is the natural exponent, i is the imaginary unit, ω is the fundamental frequency,

[0040] S105: Determine the warping type and warping degree according to the discrete Fourier series of the edge sampling points.

[0041] In S105, in one possible embodiment, determining the warpage type and degree of warpage based on the discrete Fourier series of the edge sampling points includes: calculating the amplitude and phase of the first and third terms of the discrete Fourier series of the edge sampling points to determine the warpage type of the wafer 201 to be inspected; and superimposing the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points to calculate the degree of warpage of the wafer 201 to be inspected. At least the first three terms of the discrete Fourier series of the edge sampling points can represent the overall distribution of the discrete edge sampling points, which can reduce the amount of computation. However, since noise or errors may exist during image acquisition and processing, fitting the edge sampling points using only the first three terms of the discrete Fourier series can provide both denoising and filtering.

[0042] In S101 , before acquiring the circumferential side image of the reference wafer, the process further includes: utilizing the collector 202 to acquire the circumferential side image of the reference wafer.

[0043] In a specific embodiment, a collector 202 is used to collect a circumferential side image of a reference wafer, including: placing the reference wafer on a rotatable turntable 203, aligning the center of the reference wafer with the center of the turntable 203, aligning the collector 202 with the side of the reference wafer and fixing the position, and rotating the turntable 203 to rotate the reference wafer, so that the collector 202 can continuously scan and photograph the circumferential side of the reference wafer to form a circumferential side image of the reference wafer.

[0044] In another specific embodiment, the collector 202 is used to collect the circumferential side image of the reference wafer, including: placing the reference wafer on a carrier plate, aligning the collector 202 with the side of the reference wafer, and controlling the collector 202 to rotate with the center of the reference wafer as the rotation center and the distance between the collector 202 and the reference wafer as the radius, so that the collector 202 can continuously scan and photograph the circumferential side of the reference wafer to form the circumferential side image of the reference wafer.

[0045] Specifically, the collector 202 is an image collector, for example, a line scan camera.

[0046] In S101, image processing is performed on the circumferential side image of the reference wafer to obtain a reference wafer edge image and reference coordinate information of edge sampling points in the reference wafer edge image. This includes grayscale processing of the circumferential side image of the reference wafer to obtain a grayscale image of the reference wafer, transversely intercepting the area between two cuts of the reference wafer from the grayscale image of the reference wafer, and customizing the detection area in the longitudinal direction as required to extract a contour detection image of the reference wafer. The area between the two cuts in the circumferential side image of the reference wafer represents the entire circumferential side of the reference wafer, thereby intercepting a complete cycle of the reference wafer for image processing. The image threshold of the contour detection image of the reference wafer is adjusted based on the image acquisition situation, and the thresholded contour detection image of the reference wafer is processed using an edge detection operator to obtain an edge image of the reference wafer, and the reference coordinate information of the edge sampling points in the edge image of the reference wafer is extracted. The edge detection operator may be a longitudinal 3×3 Sobel edge detection operator, a Canny edge detection operator, or other edge detection operator.

[0047] In S101, in a preferred embodiment, extracting detection coordinate information of edge sampling points in the edge image of the reference wafer includes extracting detection coordinate information of a group of edge sampling points at the top or bottom of the edge image of the reference wafer. Specifically, a pixel rectangular coordinate system μ-ν is established with the lower left corner of the edge image of the reference wafer as the origin and two adjacent sides as coordinate axes. The reference coordinate information of the group of edge sampling points at the top or bottom of the edge image of the reference wafer, i.e., the edge sampling points on the upper or lower surface of the reference wafer, is extracted column by column.

[0048] In S102 , before acquiring the circumferential side image of the wafer 201 to be inspected, the process further includes: utilizing the collector 202 to acquire the circumferential side image of the wafer 201 to be inspected.

[0049] In a specific embodiment, see Figure 2 , using the collector 202 to collect the circumferential side image of the wafer to be inspected 201, including: placing the wafer to be inspected 201 on a rotatable turntable 203, aligning the center of the wafer to be inspected 201 with the center of the turntable 203, aligning the collector 202 with the side of the wafer to be inspected 201 and fixing its position, and rotating the turntable 203 to rotate the wafer to be inspected 201, so that the collector 202 can continuously scan and photograph the circumferential side of the wafer to be inspected 201 to form the circumferential side image of the wafer to be inspected 201.

[0050] In another specific embodiment, the collector 202 is used to collect the circumferential side image of the wafer to be inspected 201, including: placing the wafer to be inspected 201 on a carrier plate, aligning the collector 202 with the side of the wafer to be inspected 201, controlling the collector 202 to rotate with the center of the wafer to be inspected 201 as the rotation center and the distance between the collector 202 and the wafer to be inspected 201 as the radius, so that the collector 202 can continuously scan and photograph the circumferential side of the wafer to be inspected 201 to form the circumferential side image of the wafer to be inspected 201.

[0051] In S102, image processing is performed on the circumferential side image of the wafer 201 to be inspected to obtain an edge image of the wafer 201 to be inspected and reference coordinate information of edge sampling points in the edge image of the wafer 201 to be inspected. This includes grayscale processing of the circumferential side image of the wafer 201 to be inspected to obtain a grayscale image of the wafer 201 to be inspected, horizontally intercepting the area between two cuts of the wafer 201 to be inspected from the grayscale image of the wafer 201 to be inspected, and vertically setting a detection area as required to thereby extract a contour detection image of the wafer 201 to be inspected. The image threshold of the contour detection image of the wafer 201 to be inspected is adjusted based on the image acquisition situation. The thresholded contour detection image of the wafer 201 to be inspected is processed using an edge detection operator to obtain an edge image of the wafer 201 to be inspected, and the detection coordinate information of the edge sampling points in the edge image of the wafer 201 to be inspected is extracted. The edge detection operator may be a longitudinal 3×3 Sobel edge detection operator, a Canny edge detection operator, or other edge detection operator.

[0052] In S102, in a preferred embodiment, the detection coordinate information of the edge sampling points in the edge image of the wafer to be inspected 201 is extracted, including: based on the edge sampling points obtained by the reference wafer, correspondingly extracting the detection coordinate information of the top or bottom set of edge sampling points in the edge image of the wafer to be inspected 201, that is, if the top set of edge sampling points in the edge image of the reference wafer (i.e., the upper edge sampling points of the reference wafer) are obtained, then the top set of edge sampling points in the edge image of the wafer to be inspected (i.e., the upper edge sampling points of the wafer to be inspected 201) are correspondingly obtained; if the bottom set of edge sampling points in the edge image of the reference wafer (i.e., the lower edge sampling points of the reference wafer) are obtained, then the bottom set of edge sampling points in the edge image of the wafer to be inspected (i.e., the lower edge sampling points of the wafer to be inspected 201) are correspondingly obtained. The upper and lower edges of the wafer are parallel, and there is no difference between the two in warpage judgment. Selecting the top edge sampling points or the bottom edge sampling points for calculation can reduce the amount of calculation and improve detection efficiency.

[0053] Specifically, a pixel rectangular coordinate system μ-ν is established with the lower left corner of the edge image of the wafer 201 to be inspected as the origin and the two adjacent sides as coordinate axes, and the detection coordinate information P={(μ,ν)|μ=0,1,2,...,N-1} of the topmost or bottommost group of edge sampling points in the edge image of the wafer 201 to be inspected is extracted column by column, that is, the edge sampling points of the upper surface or lower surface of the wafer 201 to be inspected.

[0054] In S105, in a preferred embodiment, the amplitude and phase of the first and third terms of the discrete Fourier series of the edge sampling point are calculated to determine the warpage type of the wafer 201 to be inspected, including: n Calculate the amplitude A0 and phase of the first term of the discrete Fourier series of the edge sampling point and the amplitude A2 of the third term; if the amplitude A0 of the first term of the discrete Fourier series is the largest, it is determined that the wafer 201 to be inspected is bowl-shaped. If the phase of the first term of the discrete Fourier series is is 0, the bowl is facing upwards, if the phase of the first term of the discrete Fourier series is π, the bowl mouth is downward; if the amplitude A2 of the third term of the discrete Fourier series is the largest, it is determined that the wafer 201 to be inspected is saddle-shaped.

[0055] In a specific embodiment, according to the Fourier series c n Calculating the amplitude A0 of the first term and the amplitude A2 of the third term of the discrete Fourier series of the edge sampling point includes: performing frequency normalization on the discrete Fourier series of the edge sampling point, that is, mapping the horizontal coordinate of the edge sampling point from [0, N) to [0, 2π), and obtaining k=0,1,2,...,N-1, where c n are the Fourier coefficients, p[k] represents the vertical coordinate deviation value of the kth edge sampling point, N represents the total number of discrete edge sampling points, n is the number of terms in the discrete Fourier series, e is the natural exponent, i is the imaginary unit, ω is the fundamental frequency, After normalization, the period T = 2π, the fundamental frequency where c n ,n=0,1,2,...,N-1, the corresponding frequency ω n =nω, amplitude Phase Then we get the frequency sequence ω0,ω1,ω2,...,ω N-1 , amplitude sequence A0,A1,A2,...,A N-1 , phase sequence

[0056] In S105, in a preferred embodiment, the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points are superimposed to calculate the warpage of the wafer 201 to be detected, including: taking the center point of the upper surface of the wafer 201 to be detected as the pole, the upper surface of the wafer 201 to be detected perpendicularly upward as the Z axis, the polar axis pointing to the notch of the wafer 201 to be detected, and the polar angle direction being consistent with the image scanning direction, establishing a spatial polar coordinate system, and calculating the warpage of the wafer 201 to be detected according to the discrete Fourier series components of the edge sampling points. k=0,1,2,...,N-1, the spatial function z of at least the first three terms of the discrete Fourier series of the edge sampling point is calculated using the following formula k And superimpose: Among them, α is a parameter, α is artificially set, and the significance of wafer warpage can be adjusted by adjusting the α parameter, ρ is the extreme value, θ is the extreme angle, and A k represents the magnitude of the kth component, ω k represents the frequency of the kth component, Indicates the phase of the kth component. Preferably, the range of n is greater than or equal to 2 and less than or equal to 9. When n is 2, it is the spatial function z of the first three terms of the discrete Fourier series k When n is 9, it is the spatial function z of the first ten terms of the discrete Fourier series. k Superposition. Using the first few terms of the discrete Fourier series to filter and fit the edge sampling points can not only reduce the amount of calculation, but also achieve denoising and filtering functions. The warp of the wafer is the difference between the highest and lowest points on the outer edge of the wafer. When ρ = 1, θ∈[0,2π), z = f(1,θ), and the warp of the wafer 201 to be tested is equal to the difference between the maximum and minimum values ​​of z = f(1,θ).

[0057] In a preferred embodiment, before calculating the warpage of the wafer 201 to be inspected, the process further includes obtaining the conversion relationship between coordinate points in the world coordinate system and coordinate points in the pixel coordinate system. This is known as camera calibration. Specifically, a pre-set calibration plate is photographed, and based on the pixel positions of the calibration plate's feature points in the image and their real-world positions, the conversion relationship between the pixel points in the pixel coordinate system and the wafer side points in the world coordinate system is calculated. This determines whether a pixel point in the image corresponds to a point in the real world.

[0058] Furthermore, after superimposing the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points to calculate the warpage of the wafer 201 to be inspected, the method further includes converting the warpage of the wafer 201 to be inspected into a warpage value in a world coordinate system according to the conversion relationship. The warpage pixel value calculated in S105 is in the pixel coordinate system, and the warpage value in the world coordinate system can be converted according to the conversion relationship.

[0059] In a specific embodiment, after superimposing the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points, it also includes: superimposing the waveform diagrams of the spatial functions of at least the first three terms of the discrete Fourier series of the edge sampling points to obtain a morphological simulation diagram of the wafer 201 to be inspected.

[0060] In a specific embodiment, see Figure 3 , take the discrete Fourier series components of the edge sampling points k=0,1,2,...,N-1Calculate the corresponding spatial function z for at least the first three components k , the spatial function z corresponding to at least the first three components k The waveform diagram of Preferably, the range of n is greater than or equal to 2 and less than or equal to 9, and a corresponding z=f(ρ,θ) image is drawn to obtain a morphological simulation diagram of the wafer 201 to be inspected.

[0061] The simulation method in this embodiment assumes that the wafer projection radius remains unchanged, the warpage occurs along the radial direction (i.e., the warpage is relative to the center of the circle), and the radial warpage is proportional to the square of the radius. For the simulation component ω0 = 0, z = αρ 2 , which is a standard elliptical paraboloid, i.e. bowl-shaped, for the simulation component ω2=2, z=αcos2θ=α(cos 2 θ-sin 2 θ)=α(x 2 -y 2), which is a standard hyperbolic paraboloid, that is, a saddle shape. This assumption basically conforms to the actual situation and can meet actual needs. In actual situations, the analog component ω0 = 0 and the analog component ω2 = 2 generally exist at the same time. For example, although a wafer is saddle-shaped, it is more warped upward. At this time, the component ω = 0 exists and has a positive amplitude. For another example, although a wafer is bowl-shaped, one diagonal is not so warped. At this time The weight is there too.

[0062] In this embodiment, wafer warpage detection is required multiple times in the wafer production process. In the prior art, separate warpage detection is usually performed with the aid of dedicated equipment, and the detection process is relatively cumbersome. The present invention proposes a convenient wafer warpage detection method. By processing and calculating the circumferential side images of the reference wafer and the circumferential side images of the wafer to be detected 201, the deviation information of the edge sampling points is obtained. By calculating the first several terms of the discrete Fourier series of the edge sampling points, the warpage information of the detected wafer can be conveniently and quickly calculated. The warpage information includes the warpage type, warpage degree, and morphological simulation diagram. On the one hand, the wafer warpage detection method of the present invention is part of the processing algorithm of the wafer detection equipment. When detecting other items of the wafer, the wafer warpage detection can be performed together, thereby reducing the detection cost and improving the detection efficiency. It can help the factory to find problems in time to deal with defective products and improve the process, thereby improving production efficiency and chip yield. On the other hand, denoising, filtering, and fitting of the edge sampling points are achieved, thereby improving the accuracy of wafer warpage detection.

[0063] In addition, the present invention also provides a wafer warpage detection device, see Figure 4 , the device is used to implement the methods described in the above method embodiments, which includes: an acquisition unit 401, used to acquire a circumferential side image of a reference wafer and a circumferential side image of a wafer to be inspected 201; an image processing unit 402, used to perform image processing on the circumferential side image of the reference wafer to obtain a reference wafer edge image and reference coordinate information of edge sampling points in the reference wafer edge image, and to perform image processing on the circumferential side image of the wafer to be inspected 201 to obtain an edge image of the wafer to be inspected 201 and detection coordinate information of edge sampling points in the edge image of the wafer to be inspected 201; a deviation information calculation unit 403, used to obtain deviation information of the edge sampling point based on the detection coordinate information and the reference coordinate information; a discrete Fourier series calculation unit 404, used to calculate the discrete Fourier series of the edge sampling point based on the deviation information of the edge sampling point; a warpage detection unit 405, used to determine the warpage type and warpage degree based on the discrete Fourier series of the edge sampling point. All relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here.

[0064] In other embodiments of the present application, an electronic device is disclosed. Figure 5 The electronic device may include: one or more processors 501; a memory 502; a display 503; one or more applications (not shown); and one or more computer programs 504. The above components may be connected via one or more communication buses 505. The one or more computer programs 504 are stored in the memory 502 and configured to be executed by the one or more processors 501. The one or more computer programs 504 include instructions, which may be used to execute the following instructions: Figure 1 and Figure 4 and each step in the corresponding embodiment.

[0065] Through the description of the above embodiments, those skilled in the art will clearly understand that for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0066] The functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0067] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as flash memory, mobile hard disk, read-only memory, random access memory, magnetic disk or optical disk.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A wafer warpage detection method, characterized in that: The method comprises: Acquire a peripheral side image of a reference wafer, and perform image processing on the peripheral side image of the reference wafer to obtain a reference wafer edge image and reference coordinate information of edge sampling points in the reference wafer edge image; Acquire a circumferential side image of a wafer to be inspected, and perform image processing on the circumferential side image of the wafer to be inspected to obtain an edge image of the wafer to be inspected and detection coordinate information of edge sampling points in the edge image of the wafer to be inspected; Obtaining deviation information of edge sampling points according to the detection coordinate information and the reference coordinate information; Calculating the discrete Fourier series of the edge sampling points according to the deviation information of the edge sampling points; Determining a warping type and a warping degree according to a discrete Fourier series of the edge sampling points; The discrete Fourier series satisfies the following formula: ； in, are the Fourier coefficients, , Indicates the The vertical coordinate deviation value of the edge sampling point, Represents the total number of discrete edge sampling points, is the number of terms in the discrete Fourier series, is the natural index, is the imaginary unit, is the fundamental frequency, ; Determining a warping type and a warping degree according to a discrete Fourier series of the edge sampling point includes: Calculating the amplitude and phase of the first and third terms of the discrete Fourier series of the edge sampling point to determine the warpage type of the wafer to be inspected; The first several spatial functions of the discrete Fourier series of the edge sampling points are superimposed to calculate the warpage of the wafer to be inspected.

2. The method according to claim 1, characterized in that Calculating the amplitude and phase of the first and third terms of the discrete Fourier series of the edge sampling point to determine the warpage type of the wafer to be inspected includes: If the amplitude of the first term of the discrete Fourier series is The maximum value is the largest, then the wafer to be inspected is judged to be bowl-shaped. If the phase of the first term of the discrete Fourier series is is 0, the bowl is facing upwards, if the phase of the first term of the discrete Fourier series for , the bowl mouth faces downward; If the amplitude of the third term of the discrete Fourier series is is the largest, it is determined that the wafer to be inspected is saddle-shaped.

3. The method according to claim 1, characterized in that Superimposing the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points to calculate the warpage of the wafer to be inspected includes: According to the discrete Fourier series components of the edge sampling points , the following formula is used to calculate the spatial function of at least the first three terms of the discrete Fourier series of the edge sampling point And superimpose: ； ； in, is the parameter, is an extreme value, is the polar angle, Indicates the The amplitude of the component, Indicates the The frequency of the component, Indicates the The phase of the components; when hour, , the warpage of the wafer to be tested is equal to The difference between the maximum and minimum values ​​of .

4. The method according to claim 3, characterized in that After superimposing the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points, the method further includes: superimposing waveform diagrams of the spatial functions of at least the first three terms of the discrete Fourier series of the edge sampling points to obtain a morphological simulation diagram of the wafer to be inspected.

5. A wafer warpage detection device, characterized in that: The device comprises: An acquisition unit, configured to acquire a circumferential side image of the reference wafer and a circumferential side image of the wafer to be inspected; an image processing unit configured to perform image processing on the circumferential side image of the reference wafer to obtain a reference wafer edge image and reference coordinate information of edge sampling points in the reference wafer edge image, and to perform image processing on the circumferential side image of the wafer to be detected to obtain a wafer edge image to be detected and detection coordinate information of edge sampling points in the wafer edge image to be detected; a deviation information calculation unit, configured to obtain deviation information of an edge sampling point based on the detection coordinate information and the reference coordinate information; a discrete Fourier series calculation unit, configured to calculate the discrete Fourier series of the edge sampling point according to the deviation information of the edge sampling point; a warping detection unit, configured to determine a warping type and a warping degree based on a discrete Fourier series of the edge sampling points; The discrete Fourier series satisfies the following formula: ； in, are the Fourier coefficients, , Indicates the The vertical coordinate deviation value of the edge sampling point, Represents the total number of discrete edge sampling points, is the number of terms in the discrete Fourier series, is the natural index, is the imaginary unit, is the fundamental frequency, ; The warping detection unit determines the warping type and warping degree according to the discrete Fourier series of the edge sampling points, and is specifically used to: Calculating the amplitude and phase of the first and third terms of the discrete Fourier series of the edge sampling point to determine the warpage type of the wafer to be inspected; The first several spatial functions of the discrete Fourier series of the edge sampling points are superimposed to calculate the warpage of the wafer to be inspected.

6. The device according to claim 5, characterized in that The warpage detection unit calculates the amplitude and phase of the first and third terms of the discrete Fourier series of the edge sampling point to determine the warpage type of the wafer to be detected, specifically for: If the amplitude of the first term of the discrete Fourier series is The maximum value is the largest, then the wafer to be inspected is judged to be bowl-shaped. If the phase of the first term of the discrete Fourier series is is 0, the bowl is facing upwards, if the phase of the first term of the discrete Fourier series for , the bowl mouth faces downward; If the amplitude of the third term of the discrete Fourier series is is the largest, it is determined that the wafer to be inspected is saddle-shaped.

7. The device according to claim 5, characterized in that The warpage detection unit superimposes the spatial functions of the first several terms of the discrete Fourier series of the edge sampling points to calculate the warpage of the wafer to be detected, specifically for: According to the discrete Fourier series components of the edge sampling points , the following formula is used to calculate the spatial function of at least the first three terms of the discrete Fourier series of the edge sampling point And superimpose: ； ； in, is the parameter, is an extreme value, is the polar angle, Indicates the The amplitude of the component, Indicates the The frequency of the component, Indicates the The phase of the components; when hour, , the warpage of the wafer to be tested is equal to The difference between the maximum and minimum values ​​of .

8. The device according to claim 7, characterized in that The device further comprises: The morphology simulation unit is used to superimpose the waveform diagrams of the spatial functions of at least the first three terms of the discrete Fourier series of the edge sampling points to obtain a morphology simulation diagram of the wafer to be inspected.

9. An electronic device, characterized in that: include: A processor and a memory, wherein the memory is used to store computer programs; The processor is configured to execute the computer program stored in the memory, so as to enable the electronic device to perform the method according to any one of claims 1 to 4.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 4 is implemented.

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