A defect detection system and detection method based on bright and dark field and white light interference

Abstract

The present invention discloses a bright-field and dark-field and white-light interferometry defect detection system and method. The system includes a bright-field and dark-field defect detection module, a white-light interferometry defect detection module, a transmission module, and a host computer module. The bright-field and dark-field defect detection module includes bright-field imaging and dark-field imaging, and achieves global defect detection of patterned sapphire substrates through point-by-point scanning. Based on the defect detection of the bright-field and dark-field defect detection module and the defect positioning of the transmission module, the white-light interferometry defect detection module achieves high-precision quantitative detection of defects. The host computer module includes control of the transmission module, image acquisition control, and an image data processing module. The image data processing module includes defect position extraction of bright-field images and dark-field images and three-dimensional defect morphology restoration of the white-light interferometry module. The transmission module includes point-by-point scanning detection of the bright-field and dark-field defect detection modules to provide displacement and defect positioning. It not only solves the problem of large-scale defect detection of patterned sapphire substrates but also achieves high-precision measurement of the three-dimensional morphology of defects.

Description

Technical Field

[0001] The present invention relates to the field of optical detection, and in particular to a system and method for detecting defects in a patterned sapphire substrate by using bright and dark fields and white light interference. Background Art

[0002] At present, resources are scarce, and the global energy-saving equipment industry has formed a certain scale and is developing rapidly. LED lighting, as a green lighting product, is an important energy-saving and environmental protection means in the context of the current energy crisis, greenhouse effect and ecological environment deterioration.

[0003] Patterned sapphire substrate (PSS) technology, a maskless, non-interrupted lateral merging growth technique, not only effectively reduces dislocation density with the epitaxial layer but also improves light extraction efficiency in LEDs, making it a commonly used technique for increasing LED lighting brightness. Patterned sapphire substrate technology uses photolithography and etching techniques to create periodic patterns on a single-polished sapphire substrate. Quality inspection of patterned sapphire substrates has become a crucial component of the LED industry chain. Improving the inspection efficiency and accuracy of patterned sapphire substrates can significantly increase LED production capacity. Currently, the main detection methods commonly used to detect patterned sapphire substrates include 3D microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). However, conventional 3D microscopy has low single-chip scanning efficiency, making it difficult to meet the detection requirements of mass production; SEM detection objects are limited in size, require the sample surface to be conductive, and need to be detected in a vacuum environment, making it difficult to achieve instant and efficient detection; AFM detection will cause serious probe wear, requiring timely probe replacement, and has low detection efficiency. Based on this, a method that can achieve both global defect detection of patterned sapphire substrates and three-dimensional high-precision quantitative measurement of defects is very necessary.

[0004] Chinese patent application CN109459417A discloses a method and apparatus for inspecting patterned substrates. An optical detector obtains the reflectivity or transmittance values of multiple independent annular regions from the center to the edge of the patterned substrate surface. A control unit then calculates the average and deviation of the multiple reflectivity or transmittance values within each annular region and compares them with a preset reflectivity or transmittance threshold of the target patterned substrate to determine whether the wafer under test is qualified. While this method can only determine the uniformity of the patterned substrate surface, it cannot visually observe the morphology of defects or calculate their size, and the information obtained about defects in the patterned substrate is very limited.

[0005] Chinese patent application CN217655026U discloses a brightfield and darkfield inspection device that incorporates a brightfield spot offset unit within a brightfield illumination unit to increase the spacing between the brightfield and darkfield light spots, thereby preventing crosstalk between the two. This method ensures the accuracy of both brightfield and darkfield inspections and effectively improves the accuracy of defect detection. However, for semiconductor inspection, two-dimensional imaging alone is difficult to distinguish defect types and cannot capture the surface topography of defects.

[0006] Chinese patent application CN114264664A discloses a defect detection system based on bright and dark field and structured light detection. The method includes a bright and dark field defect detection module and a structured light detection module. In the structured light detection module, a light source projection device projects a sinusoidal stripe pattern onto the lens to be tested, controls the acquisition device to collect the structured light image, performs phase analysis on the collected image, obtains the defect position with depth information in the phase image, marks the defect position on the lens, and controls the transmission module to move to the bright and dark field defect detection module for detection. However, the structured light detection process is easily affected by external light sources, which cause large errors in the coordinate values of the acquired point cloud data. Optical detection usually requires darkroom testing, which places high demands on the detection environment and is difficult to meet in-situ detection requirements on the production line.

[0007] In summary, the optical detection devices in the existing technology, including bright field detection devices, dark field detection devices, light reflectivity detection methods, etc., are respectively aimed at detecting different processes and different types of defects. However, the defect information obtained by these detection devices is limited, and the detection effect is difficult to adapt to the current process requirements. A system and method for global, high-precision three-dimensional defect detection of patterned sapphire substrates is needed, and the detection efficiency and detection accuracy need to be improved. Summary of the Invention

[0008] The present invention provides a bright-field, dark-field and white-light interference defect detection system and detection method, which overcomes the shortcomings of the background technology.

[0009] One of the technical solutions adopted by the present invention to solve its technical problem is: a defect detection system for bright and dark field and white light interference detection, including a bright and dark field defect detection module, a white light interference defect detection module, an image data processing module, a transmission module and a host computer module;

[0010] The bright and dark field defect detection module and the white light interference defect detection module include a lens barrel, an objective lens turret, a bright and dark field microscope objective lens, an interference objective lens, a first light source, a second light source, and an image acquisition device. The image acquisition device is arranged directly above the lens barrel. A beam splitter and a tubular lens are arranged inside the lens barrel. The objective lens turret is connected directly below the lens barrel and is provided with two objective lens interfaces. The bright and dark field microscope objective lens and the interference objective lens are respectively connected to the two objective lens interfaces of the objective lens turret.

[0011] The bright and dark field defect detection module realizes bright field imaging and dark field imaging; the bright field imaging uses a first light source, a spectroscope, a bright and dark field microscope objective lens, an objective lens turret and an image acquisition device, and the light emitted by the light beam emitted by the first light source passes through the spectroscope and the bright and dark field microscope objective lens to reach the surface of the patterned sapphire substrate of the sample, and is reflected by the surface of the patterned sapphire substrate and then passes through the bright and dark field microscope objective lens and the spectroscope in sequence to reach the image acquisition device; the dark field imaging uses a second light source, a spectroscope, a bright and dark field microscope objective lens, an objective lens turret and an image acquisition device, and the light beam emitted by the second light source is irradiated on the sample directly below the image acquisition device, and is reflected by the surface of the patterned sapphire substrate and then is incident on the bright and dark field microscope objective lens and the spectroscope in sequence to reach the image acquisition device;

[0012] The white light interference defect detection module uses a first light source, a spectroscope, a bright and dark field microscope objective lens, an objective lens turret and an image acquisition device. The light beam emitted by the first light source is incident on the spectroscope and the interference objective lens in sequence, reaches the surface of the patterned sapphire substrate, and is reflected by the patterned sapphire substrate and then reaches the interference objective lens and the spectroscope in sequence, and then reaches the image acquisition device.

[0013] The bright and dark field defect detection module and the white light interference defect detection module realize switching between the bright and dark field detection mode and the white light interference detection mode by rotating the objective lens turret;

[0014] The transmission module includes an x-axis translation stage, a y-axis translation stage arranged on the x-axis translation stage, and a wafer stage arranged on the y-axis translation stage, and the patterned sapphire substrate is arranged on the wafer stage; the host computer module identifies the data collected by the image acquisition device through the image data processing module in the bright and dark field defect detection module and obtains the defect position. If there are multiple defects on the patterned substrate to be tested, the defect positions are marked one by one, and the marked defect position coordinates are calculated, the position coordinate difference of the image acquisition device is calculated, and the transmission device is driven to locate the defect.

[0015] In one embodiment, the first light source is a white light source, the second light source is a 405 nm laser point light source, the image acquisition device is a CCD camera, and the beam splitter is a 45° semi-transparent and semi-reflective beam splitter.

[0016] In one embodiment: the bright and dark field defect detection module and the white light interference defect detection module also include a screw-nut mechanism, which is provided with a motion platform that can move up and down, and the movement of the lens barrel is controlled by the up and down movement of the motion platform to achieve focusing of bright and dark field and white light interference detection.

[0017] In one embodiment: the bright and dark field defect detection module and the white light interference defect detection module also include piezoelectric ceramics, the lens barrel is arranged on the piezoelectric ceramics, and the piezoelectric ceramics are arranged on a moving platform, wherein the piezoelectric ceramics realize the collection of interference fringe images by controlling the vertical scanning step length of the piezoelectric ceramics during white light interference detection.

[0018] In one embodiment, the piezoelectric ceramic movable end is connected to a lens barrel, which is connected to an image acquisition device and an objective lens turret. The piezoelectric ceramic is connected to the lens barrel to control the movement of the lens barrel, the image acquisition device, the objective lens turret, and the interference objective lens in a direction perpendicular to the substrate surface.

[0019] In one embodiment, the light beam emitted by the first light source is perpendicularly incident on the surface of the patterned sapphire substrate, and the light beam emitted by the second light source is obliquely incident on the surface of the patterned sapphire substrate at a certain angle.

[0020] In one embodiment: the bright and dark field defect detection module and the white light interference defect detection module also include a lifting mechanism and an angle adjuster, the second light source is arranged on the angle adjuster, and the angle adjuster is arranged on the lifting mechanism, and the height of the second light source and the incident angle of the light source are adjusted by the lifting mechanism and the angle adjuster.

[0021] The second technical solution adopted by the present invention to solve the technical problem is: a detection method of a defect detection system using bright and dark field and white light interference detection, wherein the host computer module executes the following instructions:

[0022] S1: When the objective turret is switched to the bright-field and dark-field microscope objective, that is, the bright-field and dark-field detection mode, the first light source is controlled to project onto the patterned sapphire substrate to be measured, and the acquisition device is controlled to acquire a bright-field image;

[0023] S2: The host computer module controls to turn off the first light source, turn on the second light source, project a dark field spot onto the patterned sapphire substrate to be measured, and controls the acquisition device to acquire a dark field image;

[0024] S3: The host computer module controls the transmission module to locate to the next detection point and repeats steps S1-S2 until the global detection of the sample is completed;

[0025] S4: Based on the bright and dark field images, the image data processing module processes the image data to obtain the defect location and mark it;

[0026] S5: Control the transmission module to sequentially move the defect positions to directly below the optical path;

[0027] S6: The objective lens turret is switched to the interference objective lens, i.e., white light interferometry detection mode, and the first light source is controlled to project onto the patterned sapphire substrate to be measured. The host computer module controls the piezoelectric ceramic scanning step size and collects the interference fringe image;

[0028] S7: The image data processing module processes the image data of a series of interference fringe images to obtain the three-dimensional morphology of the defect surface.

[0029] In one embodiment, the image data processing in step S4 includes: image fusion of bright field image and dark field image, image enhancement, defect segmentation, defect boundary extraction, and defect center pixel coordinate extraction.

[0030] In one embodiment, the image data processing in step S7 includes image preprocessing and three-dimensional shape restoration using a centroid algorithm to obtain the three-dimensional shape of the defect.

[0031] Compared with the background technology, this technical solution has the following advantages:

[0032] The bright-field and dark-field defect detection modules and the white-light interferometry defect detection module share an optical path and a camera, and switching between the two modes is achieved through the objective lens turret. The entire detection system is compact and low-cost, while also avoiding the repeated positioning errors of defects caused by the difference in optical path position from the bright-field and dark-field defect detection modules to the white-light interferometry defect detection module during defect re-inspection. By combining bright-field imaging with dark-field imaging and fusing bright-field and dark-field images, the defect detection rate can be effectively improved with a high accuracy rate. By integrating the bright-field and dark-field defect detection modules with the white-light interferometry defect detection module, bright-field and dark-field defect detection achieves global defect detection of patterned sapphire substrates, while the white-light interferometry defect detection module re-inspects defects detected in bright and dark fields, obtaining high-precision three-dimensional morphological defects. This ensures the accuracy of defect detection while meeting the requirements of patterned global detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] Figure 1 1 is a schematic structural diagram of a defect detection system using bright and dark field and white light interferometry detection according to an embodiment;

[0035] Figure 2 is a block diagram of a defect detection system using bright and dark field and white light interferometry detection according to an embodiment;

[0036] Figure 3 1 is a schematic diagram of a defect detection process using bright and dark field and white light interferometry detection in an embodiment;

[0037] Figure 4 is a schematic diagram of light rays of a bright field imaging module according to an embodiment;

[0038] Figure 5 is a flow chart of a brightfield imaging light path according to an embodiment;

[0039] Figure 6This is a light schematic diagram of a dark field imaging module according to an embodiment;

[0040] Figure 7 is a flow chart of a light path of a dark field imaging module according to an embodiment;

[0041] Figure 8 is a scanning path diagram of a bright and dark field defect detection module in an embodiment;

[0042] Figure 9 This is a schematic diagram of the light rays of the white light interference defect detection module of the embodiment;

[0043] Figure 10 is a flow chart of the light path of the white light interferometry defect detection module of an embodiment;

[0044] Explanation of reference numerals: 11-Z-axis translation stage; 111-stepping motor; 112-Z-axis translation guide rail; 113-screw; 114-motion platform; 12-lens barrel; 13-image acquisition device; 14-piezoelectric ceramic; 15-first light source; 16-objective lens turret; 17-bright-field and dark-field microscope objective lens; 18-interference objective lens; 19-second light source; 20-angle adjuster; 21-Z-axis guide rail stage; 22-transmission device; 221-y-axis translation stage; 222-x-axis translation stage; 223-wafer stage; 23-gantry; 24-vibration-absorbing platform; 121-tube lens; 122-45° semi-transparent and semi-reflective spectrometer; 25-patterned sapphire substrate; 251-patterned sapphire substrate defect; 252-normal periodic pattern. Implementation Method

[0045] In view of the problem that it is difficult to realize large-scale patterned sapphire substrate detection and high-precision defect detection in the prior art, the present invention provides a system and method for patterned sapphire substrate defect detection using bright and dark field and white light interferometry. Figure 1 and Figure 2 As shown, the system includes a brightfield and darkfield defect detection module, a white-light interferometry defect detection module, an image data processing module, a transmission module, and a host computer module. The brightfield and darkfield defect detection module is primarily used for global inspection of patterned sapphire substrates. The image data processing module performs image fusion of brightfield and darkfield images, image enhancement, image segmentation (defect segmentation), defect boundary extraction, and extraction of the pixel coordinates of the defect center. The transmission module provides displacement for point-by-point inspection in the brightfield and darkfield defect detection module until the patterned sapphire substrate is fully inspected. It is also used to locate defects detected by the brightfield and darkfield defect detection modules. The white-light interferometry defect detection module collects a series of interference fringe images of the defect point. The image data processing module performs image preprocessing and centroid-based 3D shape restoration to achieve high-precision 3D shape detection of the defect.

[0046] Please refer to Figure 1 The bright-field and dark-field defect detection module and the white-light interferometry defect detection module include a lens barrel 12, an objective turret 16, a bright-field and dark-field microscope objective lens 17, an interference objective lens 18, a first light source 15, a second light source 19, and an image acquisition device 13. The image acquisition device 13 is preferably a CCD camera and is located directly above the lens barrel 12. The lens barrel 12 has a built-in 45° semi-transparent and semi-reflective beam splitter prism, a tubular lens (TubeLens), and a coaxial light source interface. The objective turret 16 is connected directly below the lens barrel 12 and has two objective interfaces. The bright-field and dark-field microscope objective lens 17 is connected to one of the objective interfaces of the objective turret 16, and the interference objective lens 18 is connected to the other objective interface of the objective turret 16. The lens barrel 12 is mounted on a piezoelectric ceramic 14, which is mounted on a motion platform 114 of a Z-axis translation stage 11. During white-light interferometry detection, the piezoelectric ceramic 14 can capture interference fringe images by controlling the vertical scanning step length of the piezoelectric ceramic 14. The motion platform 114 is provided on a screw-nut mechanism, and the screw-nut displacement mechanism includes a screw 113 , a stepping motor 111 , and a displacement guide rail 112 .

[0047] The bright and dark field defect detection module realizes bright field imaging and dark field imaging, and the bright and dark field defect detection module and the white light interferometry defect detection module realize switching between the two modes through the objective lens turret 16. The motion platform 114 of the Z-axis translation stage 11 can be displaced on the screw rod 113 to realize focusing of bright and dark field and white light interferometry detection.

[0048] The brightfield image acquisition light source is provided by a first light source 15, which provides a parallel beam of light to illuminate the substrate and is almost not absorbed by the substrate or pattern material. It is a light source with high transmittance, preferably a white light source, and is connected to the coaxial light source interface of the lens barrel 12. The darkfield image acquisition light source is provided by a second light source 15, which provides a parallel beam of light to illuminate the substrate and is almost not absorbed by the substrate or pattern material. It is a light source with high transmittance. The second light source can be a laser point light source, a light-emitting diode light source, or a halogen lamp. The second light source 19 is preferably a 405nm laser light source. The second light source 19 is connected to an angle adjuster 20, which can move linearly on a Z-guide rail 21 to adjust the incident angle and incident height of the darkfield light source 19. The incident angle of the light source is incident at a certain angle from the side.

[0049] The transmission module 22 includes an x-axis translation stage 222, a y-axis translation stage 221 mounted on the x-axis translation stage 222, and a wafer stage 223 mounted on the y-axis translation stage 221. The patterned substrate to be tested is placed on the wafer stage. After the host computer module identifies and obtains the defect location in the bright-field and dark-field defect detection modules, if multiple defects exist on the patterned substrate to be tested, the defect locations are annotated one by one, and an x- and y-coordinate system is established for the entire system. The image acquisition device 13 then calibrates the position coordinates. If multiple defects exist on the patterned substrate to be tested, the defect locations are annotated one by one, and the difference between the x- and y-coordinates of the defect location and the image acquisition device is calculated. The host computer then controls the transmission device to locate the defect location on the patterned substrate detected by the bright-field and dark-field detection modules.

[0050] It also includes a shock-absorbing platform 24 and a gantry 23. The x-axis translation stage 222 and the gantry 23 of the above-mentioned transmission module 22 are both arranged on the shock-absorbing platform 24. The shock-absorbing platform 24 can reduce the image noise caused by the vibration of the entire system during the process of collecting stripes by white light interference, thereby improving the accuracy of detection.

[0051] A method for detecting defects by bright and dark field and white light interference detection comprises the following steps:

[0052] S0, the surface of the patterned sapphire substrate to be tested is etched with a tiny pattern. Currently, the size of the sapphire substrate is generally 2 inches (about 50 mm in diameter), 4 inches (about 100 mm in diameter), or 6 inches (about 150 mm in diameter). The surface pattern of the sapphire substrate is obtained by dry or wet etching, and the pattern is conical, trapezoidal, etc.;

[0053] The size of the pattern is between 100 nanometers and 10 microns;

[0054] S10, as attached Figure 3 As shown, after the transmission device 22 receives the command signal of the controller for the preset detection starting point target position, it controls the patterned sapphire substrate on the transmission device 22 to move to below the detection point.

[0055] S20, using the Z-axis translation stage 11, the motion platform 114 is driven to move up and down by rotating the lead screw 113 of the Z-axis translation stage, wherein the motion platform 114 drives the optical path to move up and down for focusing, determines the focusing height of the bright and dark field defect detection module, and ensures that the bright and dark field imaging images are in the clearest focus.

[0056] S30, during bright field imaging detection, the objective lens turret 16 rotates the bright and dark field microscope objective lens 17 to the optical axis, turns on the first light source 15, turns off the second light source 19, and controls the host computer to collect bright field images;

[0057] Further, the light path and light path in bright field imaging detection can be found in the attached Figure 4 and Figure 5 The light beam emitted by the first light source passes through a 45° semi-transparent and semi-reflective mirror 122 and a bright and dark field microscope objective lens 17 to reach the surface of the sample. The sample is a patterned sapphire substrate. When the light beam irradiates the surface of the patterned substrate, there is reflected light and scattered light in different directions. The scattered light and reflected light at the defect 251 of the patterned substrate 25 have a significant contrast with the scattered light and reflected light of the normal periodic pattern 252 in bright field imaging. After being reflected and scattered by the surface of the patterned sapphire substrate 25, the light passes through the bright and dark field microscope objective lens 17, the 45° semi-transparent and semi-reflective mirror 122 and the Tube Lens 121 in sequence to reach the image acquisition plane of the image acquisition device 13 for bright field image acquisition.

[0058] Preferably, dark field detection is another embodiment. Defect detection by combining bright and dark fields can reduce the missed detection rate of patterned substrate defect detection and improve the accuracy of defect detection. The patterned substrate dark field defect detection provided by the present invention also includes the following steps:

[0059] S40, in dark field imaging detection, the second light source 15 is turned on, the first light source 19 is turned off, and the host computer is controlled to collect dark field images;

[0060] Further, the light path and light path in dark field imaging detection can be found in the attached Figure 6 and Figure 7 The second light source can control the incident angle and incident height of the dark field light source through the Z guide stage 21 and the angle adjuster 20, and the emitted light beam reaches the sample surface. The sample is a patterned sapphire substrate. When the light beam irradiates the surface of the patterned substrate, there is reflected light and scattered light in different directions. By adjusting the incident angle of the above-mentioned second light source, most of the scattered light and reflected light of the normal periodic pattern 252 irradiated on the patterned substrate 25 do not enter the light imaging system, while most of the scattered light and reflected light of the defective area 251 on the patterned substrate 25 enter the bright and dark field microscope objective 17, the 45° semi-transparent and semi-reflective mirror 122 and the Tube Lens 121 in sequence to reach the image acquisition plane of the image acquisition device 13 for dark field image acquisition.

[0061] S50, the single-point detection field of view of the bright and dark field defect detection module is smaller than the size of the patterned sapphire substrate, so completing the global detection of the patterned sapphire substrate requires point-by-point scanning and detection until the bright and dark field defect detection module completes all point detections.

[0062] S60, when the bright field detection module has not completed the patterned sapphire substrate defect, the displacement transmission module 22 positions it to the next detection point of the patterned sapphire substrate. The motion scanning route from the previous detection point to the next detection point is shown in the attached Figure 8 The motion displacement is the width of the single imaging field of view of the bright and dark field defect detection module. After completing the positioning of the bright and dark field defect detection of the next point, continue to complete steps S30-S50 until the global inspection of the patterned sapphire substrate is completed.

[0063] S70, the collected bright field image and dark field image are processed by the image data processing module 300, specifically including image fusion, image enhancement, image segmentation, defect boundary extraction, and extraction of defect center pixel coordinates. The defect position at different points should consider the difference between the imaging optical axis center and the displacement transmission module 22 in x and y coordinates. The acquired defects are marked as X1 (x1, y1), X2 (x2, y2) ... X i (x i ,y i ).

[0064] S80, based on the defect points X1(x1,y1), X2(x2,y2)…X detected by the bright and dark field defect detection module i (x i ,y i ), by moving the transmission module 22, the defect positions X1(x1,y1), X2(x2,y2)...X i (x i ,y i ) One of the defect points is located directly below the optical path.

[0065] S90, the objective turret is switched to the interference objective lens, and the Z-axis translation stage 11 is used to drive the motion platform 114 to move up and down by rotating the screw 113 of the Z-axis translation stage, wherein the motion platform 114 drives the optical path to move up and down for focusing, and finds the focusing height at which clear interference fringes appear in the white light interference defect detection module. Then, this focusing height is continued to be moved about 1 mm in the opposite direction of the vertical scanning movement of the piezoelectric ceramic to ensure that the image collected by the white light interference fringes samples the image before the interference fringes appear, the interference fringes image, and the image after the interference in the piezoelectric ceramic scanning.

[0066] S100, driving the piezoelectric ceramic 14 to drive the white light interference defect detection module to perform vertical scanning and collect a series of interference fringe images.

[0067] Further, the light path and light path in the white light interference defect detection module are shown in the attached Figure 9 and Figure 10The interference objective lens 18 in the white light interference optical detection module adopts the existing Mirau interference type microscope objective lens. Its optical splitting system is located inside the microscope. The overall integration is modular, and the instrument system structure is more compact. In the Mirau type microscopic interference system adopted, the white light emitted by the first light source 15 enters the interference objective lens 18 after passing through the 45° semi-transparent and semi-reflective prism 122. It is then divided into two beams of light by the internal splitting system of the interference objective lens 18. One beam of light is irradiated by the reference mirror inside the interference objective lens and reflected. It passes through the splitting prism and the tube lens and reaches the image acquisition device 11. The other beam of light is irradiated by the surface of the patterned substrate and reflected. It reaches the image acquisition device 11 with the same light path. The two beams of light interfere with each other at the image acquisition device 11, and the image acquisition device 11 collects a fringe image with an interference signal.

[0068] S110, the collected series of interference fringe images are processed by the image data processing module 300, wherein the specific steps include image preprocessing, centroid method morphology restoration, obtaining a three-dimensional morphology map of the defect, and displaying the obtained defect detection results on the software interface to facilitate re-inspection personnel to quickly determine the defect type.

[0069] S120, the white light interferometry defect detection module needs to complete white light interferometry detection on all defect points in sequence. After completing one defect detection, it is determined whether the bright and dark field defect detection module has completed the detection of all defect points X1(x1,y1), X2(x2,y2)…Xi(xi,yi) in step S80.

[0070] S130, when the white light interference defect detection module has not completed the detection of the patterned sapphire substrate defect, the displacement transmission module 22 positions it to the next defect point of the patterned sapphire substrate. After completing the positioning of the next point, steps S90-S120 are continued until all defect points of the patterned sapphire substrate are detected.

[0071] The present invention provides a method for detecting defects on a patterned substrate using bright and dark fields and white light interferometry. This method can solve the problem in the prior art of detecting defects on patterned sapphire substrates that it is difficult to achieve large-scale detection while also achieving high-precision defect detection. The present invention detects defects on the patterned sapphire substrate by scanning point by point using a bright and dark field defect detection module, and performs high-precision quantitative three-dimensional morphology measurement of the defects using a white light interferometry detection module, providing new ideas for subsequent large-scale, high-precision, non-destructive optical detection.

[0072] The above description is merely a preferred embodiment of the present invention and therefore cannot be used to limit the scope of the present invention. In other words, equivalent changes and modifications made according to the scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A defect detection system using bright-field, dark-field, and white-light interferometry, characterized by: It includes bright and dark field defect detection module, white light interference defect detection module, image data processing module, transmission module and host computer module; The bright and dark field defect detection module and the white light interference defect detection module include a lens barrel, an objective lens turret, a bright and dark field microscope objective lens, an interference objective lens, a first light source, a second light source, and an image acquisition device. The image acquisition device is arranged directly above the lens barrel. A beam splitter and a tubular lens are arranged inside the lens barrel. The objective lens turret is connected directly below the lens barrel and is provided with two objective lens interfaces. The bright and dark field microscope objective lens and the interference objective lens are respectively connected to the two objective lens interfaces of the objective lens turret. The bright and dark field defect detection module realizes bright field imaging and dark field imaging; the bright field imaging uses a first light source, a spectroscope, a bright and dark field microscope objective lens, an objective lens turret and an image acquisition device. The light beam emitted by the first light source passes through the spectroscope and the bright and dark field microscope objective lens to reach the surface of the sample patterned sapphire substrate, and after being reflected by the patterned sapphire substrate surface, it passes through the bright and dark field microscope objective lens and the spectroscope in sequence and then reaches the image acquisition device; Dark-field imaging utilizes a second light source, a beam splitter, a bright-field and dark-field microscope objective, a lens turret, and an image acquisition device. The light beam from the second light source illuminates the sample directly below the image acquisition device. After being reflected by the surface of the patterned sapphire substrate, it sequentially enters the bright-field and dark-field microscope objective and the beam splitter before reaching the image acquisition device. The white light interference defect detection module uses a first light source, a spectroscope, a bright and dark field microscope objective lens, an objective lens turret and an image acquisition device. The light beam emitted by the first light source is incident on the spectroscope and the interference objective lens in sequence, reaches the surface of the patterned sapphire substrate, and is reflected by the patterned sapphire substrate and then reaches the interference objective lens and the spectroscope in sequence, and then reaches the image acquisition device. The bright and dark field defect detection module and the white light interference defect detection module realize switching between the bright and dark field detection mode and the white light interference detection mode by rotating the objective lens turret; The transmission module includes an x-axis translation stage, a y-axis translation stage provided on the x-axis translation stage, and a wafer stage provided on the y-axis translation stage, and the patterned sapphire substrate is provided on the wafer stage; the host computer module identifies the data collected by the image acquisition device through the image data processing module in the bright and dark field defect detection module and obtains the defect position; if there are multiple defects on the patterned substrate to be tested, the defect positions are marked one by one, the marked defect position coordinates are calculated, the position coordinate difference of the image acquisition device is calculated, and the transmission device is driven to locate the defect; The bright and dark field defect detection module and the white light interference defect detection module also include a screw-nut mechanism, which is provided with a motion platform that can move up and down. The up and down movement of the motion platform controls the movement of the lens barrel to achieve focusing of bright and dark field and white light interference detection; the light beam emitted by the first light source vertically irradiates the surface of the patterned sapphire substrate, and the light beam emitted by the second light source is obliquely incident on the surface of the patterned sapphire substrate at a certain angle to the surface of the patterned substrate.

2. The defect detection system of bright-field, dark-field and white-light interferometry according to claim 1, characterized in that: The first light source is a white light source, the second light source is a 405nm laser point light source, the image acquisition device is a CCD camera, and the beam splitter is a 45° semi-transparent and semi-reflective beam splitter.

3. The defect detection system of bright-field, dark-field and white-light interferometry according to claim 1, characterized in that: The bright and dark field defect detection module and the white light interference defect detection module also include piezoelectric ceramics, the lens barrel is arranged on the piezoelectric ceramics, and the piezoelectric ceramics are arranged on the motion platform. During white light interference detection, the piezoelectric ceramics realize the collection of interference fringe images by controlling the vertical scanning step length of the piezoelectric ceramics.

4. The defect detection system of bright-field, dark-field and white-light interferometry according to claim 3, characterized in that: The piezoelectric ceramic moving end is connected to the lens barrel, which is connected to the image acquisition device and the objective lens turret. The piezoelectric ceramic is connected to the lens barrel to control the movement of the lens barrel, the image acquisition device, the objective lens turret and the interference objective lens in a direction perpendicular to the substrate surface.

5. The defect detection system of bright-field, dark-field and white-light interferometry according to claim 1, characterized in that: The bright and dark field defect detection module and the white light interference defect detection module also include a lifting mechanism and an angle adjuster. The second light source is arranged on the angle adjuster, and the angle adjuster is arranged on the lifting mechanism. The height of the second light source and the incident angle of the light source are adjusted by the lifting mechanism and the angle adjuster.

6. The detection method performed by the defect detection system of bright and dark field and white light interferometry detection according to claim 3 is characterized in that: Execute the following instructions through the host computer module: S1: When the objective turret is switched to the bright-field and dark-field microscope objective, that is, the bright-field and dark-field detection mode, the first light source is controlled to project onto the patterned sapphire substrate to be measured, and the acquisition device is controlled to acquire a bright-field image; S2: The host computer module controls to turn off the first light source, turn on the second light source, project a dark field spot onto the patterned sapphire substrate to be measured, and controls the acquisition device to acquire a dark field image; S3: The host computer module controls the transmission module to locate to the next detection point and repeats steps S1-S2 until the global detection of the sample is completed; S4: Based on the bright and dark field images, the image data processing module processes the image data to obtain the defect location and mark it; S5: Control the transmission module to sequentially move the defect positions to directly below the optical path; S6: The objective lens turret is switched to the interference objective lens, i.e., white light interferometry detection mode, and the first light source is controlled to project onto the patterned sapphire substrate to be measured. The host computer module controls the piezoelectric ceramic scanning step size and collects the interference fringe image; S7: The image data processing module processes the image data of a series of interference fringe images to obtain the three-dimensional morphology of the defect surface.

7. The detection method according to claim 6, wherein: The image data processing in step S4 includes: image fusion of bright field image and dark field image, image enhancement, image segmentation, defect boundary extraction, and defect center pixel coordinate extraction.

8. The detection method according to claim 7, wherein: The image data processing in step S7 includes image preprocessing and three-dimensional shape restoration using a centroid algorithm to obtain the three-dimensional shape of the defect.

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