Dual-mode wafer surface defect detection method and system

Abstract

The invention relates to a dual-mode wafer surface defect detection method and a dual-mode wafer surface defect detection system, belongs to the technical field of optical detection, and solves the problem that a wafer surface defect detection method and a wafer surface defect detection system which are high in detection sensitivity and high in detection speed are lacked in the prior art. A structured light illumination device is adopted to generate structured light on the surface of a to-be-detected wafer, the to-be-detected wafer is controlled to move in a view field of a camera, switching between a structured light illumination mode and a shimming illumination mode is achieved by controlling the sampling frequency of the camera and the moving speed of the to-be-detected wafer, and defect detection in different illumination modes is achieved. The invention provides the dual-mode wafer surface defect detection method and the dual-mode wafer surface defect detection system which have relatively high detection sensitivity and can achieve high detection speed.

Description

Technical Field

[0001] The present invention relates to the field of optical detection technology, and in particular to a dual-mode wafer surface defect detection method and system. Background Art

[0002] Online detection of surface defects on wafers (bare wafers) requires both high detection sensitivity and mass production detection speed. It often uses the laser dark field (DarkField) scanning method. The traditional method uses a single laser beam for scanning. When there are surface defects, scattering will occur. The detector obtains the defect size and positioning information by collecting scattered light. With this method, the scattering signal decays exponentially as the defect size decreases. When the scattering signal caused by the defect reaches its limit, the scattering signal is submerged in the noise. At this time, the traditional dark field scattering method will not be able to detect the defect information. In order to further improve the sensitivity of defect detection, patent CN103018258B proposes a method of using structured light illumination, that is, using two beams of light to generate interference on the surface of the wafer to be inspected. By rotating the sample, a periodic scattering signal is generated when the defect passes through the interference field. The defect information is then extracted through Fourier transform or frequency mixing matching. Although this method can improve the sensitivity of defect detection, it uses a photodetector (photomultiplier tube) and projects the illumination spot into an elliptical shape with a long axis of 100-1000μm and a short axis of 15-100μm. There is no spatial resolution in the elliptical area, which reduces the defect positioning accuracy. At the same time, when multiple defects enter the elliptical spot at the same time, the periodic scattering signals of different defects will be superimposed and indistinguishable, which will lead to defect extraction errors or failures. In addition, the elliptical spot formed by oblique incidence projection has a low ratio of long to short axes, and the detection efficiency is still low when scanning the wafer. Furthermore, this patent only uses a beam splitter to generate two or more interfering beams. Compared with reflective and transmissive optical elements, the beam splitter will increase the loss of light, especially for the ultraviolet band, and the processing difficulty will also increase.

[0003] ZL 202310909164.5 proposes a linear structured light illumination wafer surface defect detection technology. This technology uses optical shaping to shape dual or multiple interfering beams into narrow linear light spots. These narrow light spots are then projected onto the wafer surface, where they interfere with each other, forming a fine linear structured light. The wafer surface is scanned by rotating the wafer, and a linear array camera is used to obtain spatially resolvable periodic scattered light signals. Defect information is ultimately obtained through discrete Fourier analysis or frequency mixing matching.

[0004] In summary, traditional wafer inspection methods primarily exploit the principle of light scattering by defects, directly extracting defect information by collecting scattered light intensity signals. Single-beam dark-field scattering and dual-beam interferometric illumination each have their own characteristics and advantages. Single-beam dark-field scattering offers higher speed at a given detection sensitivity, while dual-beam interferometric illumination offers higher defect detection sensitivity. However, detection sensitivity and speed are conflicting. Patent ZL 202310909164.5 proposes a method for periodically modulating scattered light signals using structured light illumination. While this improves defect detection efficiency to a certain extent, it still falls short of the efficiency of single-beam uniform-field illumination. A system combining both single-beam and structured light illumination modes offers both sensitivity and speed. Key challenges remain in ensuring the feasibility, compatibility, and ease of switching between these two modes. Typical single-beam laser dark-field scattering employs uniform-field illumination. Currently, wafer inspection optical solutions rely on either uniform-field illumination for high-speed detection or structured light for high-sensitivity detection. A single optical system that achieves both high-speed and high-sensitivity detection is lacking. Summary of the Invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide a dual-mode wafer surface defect detection method and system to solve the problem in the prior art of lacking an optical system that can achieve both high-speed detection and high-sensitivity detection.

[0006] On the one hand, an embodiment of the present invention provides a dual-mode wafer surface defect detection method, which uses a structured light illumination device to generate structured light on the surface of the wafer to be tested, controls the movement of the wafer to be tested within the camera field of view, and realizes switching between the structured light illumination mode and the uniform field illumination mode by controlling the camera sampling frequency and the movement speed of the wafer to be tested, thereby realizing defect detection under different illumination modes.

[0007] Furthermore, when the ratio of the camera sampling frequency to the moving speed of the wafer to be measured is greater than or equal to a set threshold, a structured light illumination mode is formed; when the ratio of the linear array camera sampling frequency to the moving speed of the wafer to be measured is less than the set threshold, a uniform field illumination mode is formed.

[0008] Furthermore, the threshold is set to 2 / L, where L is the period of interference fringes generated by the structured light illumination device on the surface of the wafer to be measured.

[0009] Furthermore, the wafer to be tested performs linear motion or circular motion within the camera's field of view.

[0010] On the other hand, an embodiment of the present invention provides a dual-mode wafer surface defect detection system, which includes a structured light illumination device, a camera, and a scanning mobile platform; the wafer to be tested is placed on the scanning mobile platform, the scanning mobile platform is used to drive the wafer to be tested to move, and the camera is used to image the light field on the surface of the wafer to be tested; the structured light illumination device is used to generate structured light on the surface of the wafer to be tested; by adjusting the camera sampling frequency and the moving speed of the scanning mobile platform, switching between the structured light illumination mode and the uniform field illumination mode is achieved, thereby realizing defect detection under different illumination modes.

[0011] Furthermore, the structured light illumination device includes: a laser, a beam splitter, a first reflection and shaping component, and a second reflection and shaping component; the beam splitter is used to split the light beam emitted by the laser into two light beams in different directions; the two light beams in different directions are respectively incident on the first reflection and shaping component and the second reflection and shaping component, and the light beams emitted through the first reflection and shaping component and the second reflection and shaping component generate interference on the surface of the wafer to be measured to form structured light.

[0012] Furthermore, the first reflection shaping component and the second reflection shaping component have the same structure, both including a reflector and a first shaping component. The reflector is used to reflect the light beam emitted by the beam splitter to the first shaping component, and the first shaping component is used to shape the incident light beam into a thin strip-shaped light spot and project it onto the surface of the wafer to be tested.

[0013] Furthermore, the structured light illumination device includes a first laser, a second shaping component, a third shaping component, and a first reflector; the second shaping component shapes the light beam emitted by the first laser into a thin strip-shaped light spot and projects it onto the surface of the wafer to be measured; the thin strip-shaped light spot is reflected by the surface of the wafer to be measured and then incident on the third shaping component; the third shaping component converts the parallel light beam into a parallel light beam and then incident on the first reflector; the first reflector is used to reflect the parallel light beam back to the third shaping component; after being shaped into a thin strip-shaped light spot by the third shaping component, the parallel light beam interferes with the thin strip-shaped light spot shaped and emitted by the second shaping component to generate structured light.

[0014] Furthermore, the first shaping component, the second shaping component, and the third shaping component have the same structure and all include an X-axis beam expansion component and a Y-axis beam compression component arranged in sequence along the beam propagation direction; the X-axis beam expansion component includes a first plano-convex cylindrical mirror and a plano-concave cylindrical mirror arranged in sequence along the beam propagation direction, and the Y-axis beam compression component includes a second plano-convex cylindrical mirror.

[0015] Furthermore, the system also includes an objective lens; the objective lens is located on the main light path between the wafer to be tested and the camera.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0017] 1. The method and system of the present invention use a structured light illumination device to generate structured light on the surface of the wafer to be tested, control the movement of the wafer to be tested in the camera field of view, and realize switching between the structured light illumination mode and the uniform field illumination mode by controlling the camera sampling frequency and the movement speed of the wafer to be tested, thereby realizing defect detection under different illumination modes and improving the defect positioning accuracy. At the same time, multiple defects entering the illumination light field can be detected simultaneously, thereby improving the defect detection efficiency and being able to cope with high-precision defect detection of mass-produced wafers.

[0018] 2. In the method and system of the present invention, the wafer to be tested performs linear or circular motion within the camera's field of view. When the ratio of the camera sampling frequency to the wafer's movement speed is greater than or equal to a set threshold, a structured light illumination mode is formed to achieve high-sensitivity detection. When the ratio of the linear array camera's sampling frequency to the wafer's movement speed is less than the set threshold, a uniform field illumination mode is formed to achieve high-speed defect detection. A single optical system solution achieves compatibility between high-speed and high-sensitivity detection, significantly saving economic costs. At the same time, simply by adjusting the ratio of the camera acquisition frequency to the platform's movement speed, the switch between high-sensitivity mode and high-speed mode can be easily achieved, making the system easy to convert without requiring additional additions to the system structure. A single system can simultaneously meet the requirements of both high-sensitivity and high-speed detection.

[0019] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0021] Figure 1 A schematic diagram of the dual-mode detection principle of the method and system of the present invention;

[0022] Figure 2 The optical system for detecting wafer defects using a spectral interference-dual mode method according to the present invention is provided;

[0023] Figure 3 This is the reflection interference-dual-mode wafer defect detection optical system of the present invention.

[0024] Reference numerals:

[0025] 1-Laser;

[0026] 2- beam splitter;

[0027] 3-reflector;

[0028] 4-first plano-convex cylindrical mirror;

[0029] 5- Plano-concave cylindrical mirror;

[0030] 6- second plano-convex cylindrical mirror;

[0031] 7- Camera;

[0032] 8-Objective lens;

[0033] 9-sample;

[0034] 10-X, Y, T scanning moving platform. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0036] A specific embodiment of the present invention discloses a dual-mode wafer surface defect detection method, the principle of which is as follows: Figure 1 As shown in the figure, a structured light illumination device is used to generate structured light on the surface of the wafer to be tested. The wafer to be tested is controlled to move within the field of view of camera 7. By controlling the sampling frequency of camera 7 and the movement speed of the wafer to be tested, the structured light illumination mode and the uniform field illumination mode are switched, thus achieving defect detection under different illumination modes.

[0037] Specifically, the present invention proposes a method for converting uniform field illumination and dual-beam structured light illumination. The optical path structure adopts a dual-beam structure, utilizing a single optical structure solution to achieve compatibility between high-speed and high-sensitivity detection. This means that one system performs the functions of two systems, significantly reducing economic costs. Uniform field illumination can detect large particle defects and multiple defects within a single field of view. When the wafer moves at high speeds, the superposition of sine waves prevents camera 7 from distinguishing particles between 30-50nm. Structured light illumination can detect tiny particle defects, based on the statistical characteristics of tiny particles undergoing alternating light and dark variations.

[0038] When the ratio of the sampling frequency of the camera 7 to the moving speed of the wafer to be measured is greater than or equal to the set threshold, a structured light illumination mode is formed; when the ratio of the sampling frequency of the linear array camera 7 to the moving speed of the wafer to be measured is less than the set threshold, a uniform field illumination mode is formed.

[0039] The set threshold is 2 / L, where L is the period of interference fringes generated by the structured light illumination device on the surface of the wafer to be measured.

[0040] Specifically, the switching between these two modes is achieved by controlling the speed of the X, Y, and T scanning platform 10 and matching the acquisition frequency of camera 7. When the ratio of camera 7's acquisition frequency to the platform's movement speed is greater than or equal to a given critical value, the system is considered to be structured light illumination, exhibiting high sensitivity, i.e., in high-sensitivity mode. When the ratio of camera 7's acquisition frequency to the platform's movement speed is less than the given critical value, the system degenerates into uniform field illumination, exhibiting high speed characteristics, i.e., in high-speed mode. Switching between the two modes is achieved simply by adjusting the ratio of camera 7's acquisition frequency to the platform's movement speed, making it easy to switch. This system achieves integrated compatibility between high-sensitivity and high-speed detection modes.

[0041] The camera 7 takes pictures at a line frequency of F (the present invention uses a linear array camera 7, and the line frequency refers to the line scanning frequency along the linear velocity direction of the X, Y, and T scanning mobile platform 10). The moving linear velocity of the X, Y, and T scanning mobile platform 10 is v, and the interference fringe period L satisfies the above Nyquist theorem relationship, that is:

[0042] When F≥2 / T (equivalent to F≥2v / L, F / v≥2 / L), that is, when the X, Y, and T scanning mobile platform 10 has a slow linear speed, the camera 7 takes pictures at a line frequency ≥Nyquist sampling rate, and within the camera 7's line shooting time, the mobile platform moves a distance less than half of the structured light period (v / F≤L / 2). In this case, the system is in structured light illumination mode, which can achieve high-sensitivity detection, such as Figure 1 Medium mode 1;

[0043] When F<2 / T (equivalent to F<2v / L, F / v<2 / L), the linear velocity of the X, Y, and T scanning mobile platform 10 is relatively large. During the time it takes for the camera 7 to take a single line of pictures, multiple cycles of structured light will pass through the field of view of the camera 7. At this time, one line of image taken by the camera 7 is equivalent to the accumulation of multiple cycles of structured light. The system can be equivalent to a uniform field illumination mode, which can achieve high-speed detection. Figure 1 Medium mode 2.

[0044] In a specific embodiment of the present invention, a Xintu Areas 6506 high-speed linear array camera 7 is used. When the acquisition frequency of the camera 7 is 10 kHz and the moving speed of the X, Y, and T scanning platform 10 is 10 mm / s, the interference fringe period is 300 nm. In this case, FL = 3x10 6 nm / s, 2V = 2x10 7 nm / s, that is, FL<2v, which does not satisfy the Nyquist theorem, and realizes high-speed detection in uniform field illumination mode. When the acquisition frequency of the camera 7 is F=100KHz, and the moving speed of the X, Y, T scanning moving platform 10 is 10mm / s, FL=3x10 7If nm / s > 2v, the Nyquist theorem is satisfied, and high-sensitivity detection in the structured light illumination mode can be achieved.

[0045] The wafer to be measured moves linearly or circularly within the field of view of camera 7. It can be understood that when moving linearly, the speed v is the moving speed of the wafer, and when moving circularly, the speed refers to the linear speed of the wafer.

[0046] Specifically, the wafer to be measured has defective particles; the wafer to be measured is placed on the scanning moving platform; the scanning moving platform drives the wafer to be measured to move within the field of view of the line array camera 7.

[0047] When the X, Y, T scanning moving platform 10 drives the wafer to be measured to move circularly, the moving linear speed v of the X, Y, T scanning moving platform 10 = ωr. At this time, the scanning direction of the line array camera 7 scans along any rotation radius direction of the X, Y, T scanning moving platform 10, and ω is the angular velocity of the X, Y, T scanning moving platform 10. r1 < r < r2, where r1 and r2 are the distances from the two endpoints of the scanning range of the line array camera 7 to the rotation axis. When the moving platform rotates, the line array camera 7 can scan a circular ring on the upper surface of the wafer to be measured. When F / (ωr1) ≥ 2 / L, the structured light illumination detection condition is satisfied.

[0048] When the X, Y, T scanning moving platform 10 drives the wafer to be measured to move linearly, the scanning direction of the line array camera 7 is along the direction perpendicular to the interference fringes.

[0049] Another specific embodiment of the present invention discloses a dual-mode wafer surface defect detection system, as Figure 2 、 3 shown. The system includes a structured light illumination device, camera 7, and a scanning moving platform; the wafer to be measured is placed on the scanning moving platform, and the scanning moving platform is used to drive the wafer to be measured to move, and camera 7 is used to image the light field on the surface of the wafer to be measured; the structured light illumination device is used to generate structured light on the surface of the wafer to be measured; by adjusting the sampling frequency of camera 7 and the moving speed of the scanning moving platform, the switching between the structured light illumination mode and the uniform field illumination mode is realized, and defect detection in different illumination modes is achieved.

[0050] Specifically, the pixel array of the line array camera 7 is parallel to the direction of the interference fringes, and the wafer to be measured is carried onto the scanning moving platform through a stage. A specific embodiment of the present invention uses an x, y, z, T four-axis moving platform, model: HZX873-M1. The sample 9 can be translated along the x and y axes and rotated along the T axis. When the defect sweeps across the field of view of camera 7 at a low linear speed, the periodic scattering signal (interference fringes) will be collected by the objective lens 8 and enter the line array camera 7 to form a structured light detection mode. When the defect sweeps across at a high speed, the uniform field scattering signal will be collected by the objective lens 8 and enter the line array camera 7.

[0051] In one embodiment, the optical system for detecting defects in a wafer using a spectral interference-dual mode method of the present invention is as follows: Figure 2 shown.

[0052] The structured light illumination device includes: a laser 1, a beam splitter 2, a first reflection and shaping component, and a second reflection and shaping component; the beam splitter 2 is used to split the light beam emitted by the laser 1 into two light beams in different directions; the two light beams in different directions are respectively incident on the first reflection and shaping component and the second reflection and shaping component, and the light beams emitted by the first reflection and shaping component and the second reflection and shaping component generate interference on the surface of the wafer to be measured, forming structured light.

[0053] The first reflection shaping component and the second reflection shaping component have the same structure, both including a reflector 3 and a first shaping component. The reflector 3 is used to reflect the light beam emitted by the beam splitter 2 to the first shaping component, and the first shaping component is used to shape the incident light beam into a thin strip-shaped light spot and project it onto the surface of the wafer to be tested.

[0054] The first shaping component includes an X-axis beam expansion component and a Y-axis beam compression component; the X-axis beam expansion component includes a first plano-convex cylindrical mirror 4 and a plano-concave cylindrical mirror 5 arranged in sequence along the beam propagation direction, and the Y-axis beam compression component includes a second plano-convex cylindrical mirror 6.

[0055] Specifically, the plane of the first plano-convex cylindrical mirror 4 of the first shaping component faces the reflector 3, the convex surface of the first plano-convex cylindrical mirror 4 of the first shaping component faces the concave surface of the plano-concave cylindrical mirror 5, the plane of the plano-concave cylindrical mirror 5 faces the plane of the second plano-convex cylindrical mirror 6, and the convex surface of the second plano-convex cylindrical mirror 6 is the light emitting surface of the first shaping component.

[0056] The first shaping component shapes the light beam incident on the plane of the first plano-convex cylindrical mirror 4 into a thin strip light spot with an aspect ratio greater than 1200:1, thereby improving the defect detection efficiency.

[0057] In another embodiment, the reflection interference-dual mode wafer defect detection optical system of the present invention is as follows: Figure 3 shown.

[0058] The structured light illumination device includes a first laser 1, a second shaping component, a third shaping component, and a first reflector 3; the second shaping component shapes the light beam emitted by the first laser 1 into a thin strip light spot and projects it onto the surface of the wafer to be measured. The thin strip light spot is reflected by the surface of the wafer to be measured and then incident on the third shaping component. After being converted into a parallel light beam by the third shaping component, it is incident on the first reflector 3; the first reflector 3 is used to reflect the parallel light beam back to the third shaping component. After being shaped into a thin strip light spot by the third shaping component, it interferes with the thin strip light spot shaped and emitted by the second shaping component to generate structured light.

[0059] The second shaping assembly and the third shaping assembly in this embodiment have the same structure as the first shaping assembly in the previous embodiment, and both include an X-axis beam expansion assembly and a Y-axis beam compression assembly arranged in sequence along the beam propagation direction; the X-axis beam expansion assembly includes a first plano-convex cylindrical mirror 4 and a plano-concave cylindrical mirror 5 arranged in sequence along the beam propagation direction, and the Y-axis beam compression assembly includes a second plano-convex cylindrical mirror 6.

[0060] The focal points of the first plano-convex cylindrical mirror 4 , the plano-concave cylindrical mirror 5 , and the second plano-convex cylindrical mirror 6 coincide with each other.

[0061] Specifically, the plane of the first plano-convex cylindrical mirror 4 of the second shaping assembly faces the laser 1, the convex surface of the first plano-convex cylindrical mirror 4 of the second shaping assembly faces the concave surface of the plano-concave cylindrical mirror 5, the plane of the plano-concave cylindrical mirror 5 faces the plane of the second plano-convex cylindrical mirror 6, and the convex surface of the second plano-convex cylindrical mirror 6 is the light emitting surface of the second shaping assembly.

[0062] The plane of the first plano-convex cylindrical mirror 4 of the third shaping component faces the first reflecting mirror 3, the convex surface of the first plano-convex cylindrical mirror 4 of the third shaping component faces the concave surface of the plano-concave cylindrical mirror 5, the plane of the plano-concave cylindrical mirror 5 faces the plane of the second plano-convex cylindrical mirror 6, and the convex surface of the second plano-convex cylindrical mirror 6 not only receives the reflected light from the surface of the wafer to be measured, but also shapes the light beam returned by the first reflecting mirror 3 into a thin strip of light spot, which interferes with the thin strip of light spot shaped by the second shaping component.

[0063] The system further includes an objective lens 8 ; the objective lens 8 is located on the main optical path between the wafer to be measured and the camera 7 , and is used to image the light field on the wafer surface to the camera.

[0064] In addition, the above definitions of the methods are not limited to the various specific forms, structures, shapes or methods mentioned in the embodiments, and those skilled in the art may simply modify or replace them. For example:

[0065] (1) Figure 2 、 Figure 3 The parameters of each optical element are not specially specified;

[0066] (2) Figure 2 、 Figure 3 The scanning mobile platform can be translated along the X and Y axes, or it can be rotated around the axis to scan;

[0067] (3) The critical value of F / v described in the article is 2 / L. In actual settings, when using the high sensitivity mode, the setting value of F / v can be any value greater than the critical value 2 / L; similarly, when using the high speed mode, the setting value of F / v can be any value less than the critical value 2 / L;

[0068] (4) The dual-mode detection system is not only applicable to linear structured light illumination systems, but also to traditional non-linear structured light illumination systems.

[0069] Compared to existing technologies, the method and system provided in this embodiment utilizes a structured light illumination device to generate structured light on the surface of the wafer under test, controls the movement of the wafer under test within the field of view of camera 7, and switches between structured light illumination mode and shim illumination mode by controlling the sampling frequency of camera 7 and the movement speed of the wafer under test. This enables defect detection under different illumination modes, improving defect location accuracy. Furthermore, multiple defects entering the illumination light field can be detected simultaneously, increasing defect detection efficiency and enabling high-precision defect detection on mass-produced wafers. In this embodiment, the wafer under test undergoes linear or circular motion within the field of view of camera 7. When the ratio of the sampling frequency of camera 7 to the movement speed of the wafer under test is greater than or equal to a set threshold, a structured light illumination mode is generated; when the ratio of the sampling frequency of linear array camera 7 to the movement speed of the wafer under test is less than the set threshold, a shim illumination mode is generated. This achieves both high-speed and high-sensitivity detection using a single optical system solution, significantly reducing costs. Furthermore, switching between the two modes can be achieved simply by adjusting the ratio of the acquisition frequency of camera 7 to the movement speed of the platform, making the switch easy.

[0070] Those skilled in the art will appreciate that all or part of the process steps of the above-described embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, such as a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0071] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A dual-mode wafer surface defect detection method, characterized in that: A structured light illumination device is used to generate structured light on the surface of the wafer to be tested, and the movement of the wafer to be tested within the camera field of view is controlled. By controlling the camera sampling frequency and the movement speed of the wafer to be tested, the switching between the structured light illumination mode and the uniform field illumination mode is realized, thereby realizing defect detection under different illumination modes.

2. The dual-mode wafer surface defect detection method according to claim 1, characterized in that: When the ratio of the camera sampling frequency to the moving speed of the wafer to be measured is greater than or equal to the set threshold, a structured light illumination mode is formed; when the ratio of the linear array camera sampling frequency to the moving speed of the wafer to be measured is less than the set threshold, a uniform field illumination mode is formed.

3. The dual-mode wafer surface defect detection method according to claim 2, characterized in that: The set threshold is 2 / L, where L is the period of interference fringes generated by the structured light illumination device on the surface of the wafer to be measured.

4. The dual-mode wafer surface defect detection method according to claim 1, characterized in that: The wafer to be tested moves linearly or circularly within the camera's field of view.

5. A dual-mode wafer surface defect detection system, characterized in that: The system includes a structured light illumination device, a camera, and a scanning mobile platform; the wafer to be tested is placed on the scanning mobile platform, the scanning mobile platform is used to drive the wafer to be tested to move, and the camera is used to image the light field on the surface of the wafer to be tested; the structured light illumination device is used to generate structured light on the surface of the wafer to be tested; by adjusting the camera sampling frequency and the moving speed of the scanning mobile platform, switching between the structured light illumination mode and the uniform field illumination mode is achieved, thereby realizing defect detection under different illumination modes.

6. The defect detection system according to claim 5, characterized in that: The structured light illumination device includes: a laser, a beam splitter, a first reflective shaping component, and a second reflective shaping component; the beam splitter is used to split the light beam emitted by the laser into two light beams in different directions; the two light beams in different directions are respectively incident on the first reflective shaping component and the second reflective shaping component, and the light beams emitted by the first reflective shaping component and the second reflective shaping component generate interference on the surface of the wafer to be measured, forming structured light.

7. The defect detection system according to claim 6, characterized in that: The first reflection shaping component and the second reflection shaping component have the same structure, both including a reflector and a first shaping component. The reflector is used to reflect the light beam emitted by the beam splitter to the first shaping component. The first shaping component is used to shape the incident light beam into a thin strip-shaped light spot and project it onto the surface of the wafer to be tested.

8. The defect detection system according to claim 5, characterized in that: The structured light illumination device includes a first laser, a second shaping component, a third shaping component, and a first reflector; the second shaping component shapes the light beam emitted by the first laser into a thin strip of light spot and projects it onto the surface of the wafer to be measured; the thin strip of light spot is reflected by the surface of the wafer to be measured and then incident on the third shaping component, and is converted by the third shaping component into a parallel light beam and then incident on the first reflector; The first reflector is used to reflect the parallel light beam back to the third shaping component, and after being shaped into a thin strip light spot by the third shaping component, it interferes with the thin strip light spot shaped and emitted by the second shaping component to generate structured light.

9. The defect detection system according to any one of claims 7 and 8, characterized in that: The first shaping component, the second shaping component, and the third shaping component have the same structure and all include an X-axis beam expansion component and a Y-axis beam compression component sequentially arranged along the beam propagation direction; the X-axis beam expansion component includes a first plano-convex cylindrical mirror and a plano-concave cylindrical mirror sequentially arranged along the beam propagation direction, and the Y-axis beam compression component includes a second plano-convex cylindrical mirror.

10. The defect detection system according to claim 5-9, characterized in that: The system further comprises an objective lens; the objective lens is located on the main optical path between the wafer to be measured and the camera.

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