Super-resolution multi-focus structured light illumination interference scattering microscopic imaging method and system

Abstract

The invention discloses a super-resolution multi-focus structured light illumination interference scattering microscopic imaging method and system, and the method comprises the steps: controlling a laser device to generate laser, and enabling the laser to irradiate a digital micromirror device after the laser is collimated and expanded; modulating the expanded laser by using a digital micromirror device, and transmitting the modulated laser to the surface of the wafer so as to form a multi-focus array illumination mode on the surface of the wafer; acquiring multi-focus information reflected by the surface of the wafer through a camera, and loading the multi-focus information to an illumination template of the digital micromirror device to realize scanning imaging detection of the surface of the whole wafer; and performing image reconstruction on the plurality of original dot matrix image data subjected to scanning imaging detection to obtain a super-resolution image of the wafer feature structure. According to the invention, synchronous time-sharing triggering of the high-speed digital micromirror device and the camera is adopted to realize multi-focus dot matrix illumination and scanning imaging, fluorescence labeling of the chip is not needed, and super-resolution chip feature structure and defect detection can be carried out rapidly, conveniently and reliably.

Description

Technical Field

[0001] The present invention relates to the field of optical microscopy imaging technology, and particularly relates to a super-resolution multi-focus structured illumination interference scattering microscopy imaging method and system. Background Art

[0002] In recent years, with the continuous growth of the demand for electronic devices such as smartphones, smart homes, and smart cars, the semiconductor chip industry has developed rapidly. At the same time, artificial intelligence is in the initial stage of rapid expansion, and coupled with the rapid popularization of 5G communication technology, the future demand for semiconductor chips will continue to climb. The semiconductor chip manufacturing process has undergone frequent updates, and the chip feature structure has been continuously miniaturized, posing new challenges to the existing wafer defect detection methods. It is required to evaluate semiconductor device wafers at the critical dimensions of finer patterns, and at the same time detect contaminants or defects beyond the optical diffraction limit.

[0003] Common detection methods such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) have been used to detect fine feature structures and defects in semiconductor integrated circuits. However, these imaging technologies have low throughput due to their small field of view or the requirement of high vacuum conditions, so it is time-consuming to use these technologies to image large sample areas. In contrast, optical microscopy is an imaging technology with relatively high throughput due to its relatively large field of view and the lack of the need for vacuum conditions. However, due to the limitation of the Abbe diffraction limit, useful features are submerged in the background and are interfered by different types of errors from the hardware side or the software side, making it almost impossible to see defects from the original optical image, and making it impossible for traditional optical microscopes to accurately evaluate chip feature patterns and tiny defects during imaging. For this reason, a variety of optical microscopy technologies have been developed to improve the detection speed and spatial resolution for chip detection. For example, scatterometry has been widely used in the size measurement of fine patterns on semiconductor chips due to its high measurement speed.

[0004] Although the existing scatterometry can capture sub-wavelength periodic structures, there are still limitations in measuring isolated or aperiodic structures. A method for chip defect detection using stochastic optical reconstruction microscopy (STORM) has been proposed. Although it can detect chip defects with an ultra-high lateral resolution of 20 nanometers, it requires fluorescent labeling of the chip's feature structure and needs to acquire thousands or even tens of thousands of pictures to reconstruct a super-resolution image. The slow imaging speed and difficult labeling make STORM difficult to apply in actual chip detection.

[0005] Therefore, the existing technology still needs to be improved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that, aiming at the defects of the prior art, the present invention provides a super-resolution multi-focus structured light illumination interference scattering microscopy imaging method and system to solve the problem of slow detection imaging speed existing in the existing optical microscopy technology for wafer defect detection.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows: In the first aspect, the present invention provides a super-resolution multi-focus structured light illumination interference scattering microscopy imaging method for wafer defect detection, including: Controlling a laser to generate laser light, and irradiating the laser light on a digital micromirror device after collimation and beam expansion; Using the digital micromirror device to modulate the expanded laser light, and transmitting the modulated laser light to the wafer surface to form a multi-focus array illumination pattern on the wafer surface; Collecting multi-focus information reflected from the wafer surface by a camera, and loading the multi-focus information into the illumination template of the digital micromirror device to realize the scanning imaging detection of the entire wafer surface; Performing image reconstruction on a number of original dot matrix image data obtained by the scanning imaging detection to obtain a super-resolution image of the wafer characteristic structure.

[0008] In one implementation, the controlling the laser to generate laser light, and irradiating the laser light on the digital micromirror device after collimation and beam expansion includes: Controlling the laser to emit continuous laser light; Adjusting the pitch angle of the laser light so that the propagation direction of the laser light is horizontal with the optical platform, and expanding the laser light to obtain the expanded laser light; Reflecting the expanded laser light through a reflector so that the laser light enters the working surface of the digital micromirror device at a first incident angle.

[0009] In one implementation, the diameter size of the expanded laser light is larger than the diagonal length of the working panel of the digital micromirror device.

[0010] In one implementation, the using the digital micromirror device to modulate the expanded laser light, and transmitting the modulated laser light to the wafer surface to form a multi-focus array illumination pattern on the wafer surface includes: Controlling the micro-mirrors of the digital micromirror device to remain in the open state, selecting to allow the laser light in a preset area to pass through the subsequent 4f optical path system, and transmitting it to the wafer surface at a second incident angle to form a multi-focus array illumination pattern on the wafer surface.

[0011] In one implementation, before collecting the multi-focus information reflected from the wafer surface by the camera and loading the multi-focus information into the illumination template of the digital micromirror device, the following steps are included: Load multiple black-and-white dot matrix pictures into the digital micromirror device.

[0012] In one implementation, collecting the multi-focus information reflected from the wafer surface by the camera and loading the multi-focus information into the illumination template of the digital micromirror device to realize the scanning imaging detection of the entire wafer surface includes the following steps: Collect the multi-focus information reflected from the wafer surface by the camera; Load the multi-focus information onto multiple black-and-white dot matrix pictures so that each white pixel in each black-and-white dot matrix picture corresponds to a focal point on the wafer surface; Switch the display mode in the order of the loaded black-and-white dot matrix pictures to control the movement of the focal points on the wafer surface until the entire wafer surface within the field of view is scanned.

[0013] In one implementation, performing image reconstruction on several original dot matrix image data of the scanning imaging detection to obtain a super-resolution image of the wafer characteristic structure includes the following steps: Perform pinhole filtering on several original dot matrix image data of the scanning imaging detection; Relocate the pixels in the dot matrix image data after pinhole filtering; Process the image after pixel relocation based on the deconvolution algorithm to obtain the super-resolution image of the wafer characteristic structure.

[0014] In a second aspect, the present invention provides a super-resolution multi-focus structured light illumination interference scattering microscopy imaging system, including: A laser, a mirror group, a first 4f system, a digital micromirror device, a second 4f system, a tube lens, a beam splitter, an objective lens, and a camera that are sequentially connected in an optical path; The system further includes: a digital acquisition card and a terminal; the laser, the digital micromirror device, the camera, and the digital acquisition card are respectively connected to the terminal, and the digital micromirror device and the camera are separately connected to the digital acquisition card; The terminal is used to implement the following steps: Control the laser to generate laser light and irradiate the laser light on the digital micromirror device after collimation and beam expansion; Use the digital micromirror device to modulate the expanded laser light and transmit the modulated laser light to the wafer surface to form a multi-focus array illumination pattern on the wafer surface; Collect multi-focus information reflected from the surface of the wafer through a camera, and load the multi-focus information into the illumination template of the digital micromirror device to achieve scanning imaging detection of the entire wafer surface; Perform image reconstruction on a number of original dot matrix image data obtained from the scanning imaging detection to obtain a super-resolution image of the wafer characteristic structure.

[0015] In a third aspect, the present invention provides a terminal, including: a processor and a memory, the memory stores a super-resolution multi-focus structured light illumination interference scattering microscopy program, and when the super-resolution multi-focus structured light illumination interference scattering microscopy program is executed by the processor, it is used to implement the operations of the super-resolution multi-focus structured light illumination interference scattering microscopy method as described in the first aspect.

[0016] In a fourth aspect, the present invention further provides a medium, the medium is a computer-readable storage medium, the medium stores a super-resolution multi-focus structured light illumination interference scattering microscopy program, and when the super-resolution multi-focus structured light illumination interference scattering microscopy program is executed by a processor, it is used to implement the operations of the super-resolution multi-focus structured light illumination interference scattering microscopy method as described in the first aspect.

[0017] The present invention adopts the above technical solutions and has the following effects: The multi-focus structured light illumination microscope proposed by the present invention is a parallel method for chip detection using a confocal microscope. This method uses a digital micromirror device to generate a focused dot matrix for scanning imaging. Compared with the single-point scanning imaging of a confocal microscope, it greatly improves the throughput of chip detection. This solution obtains a series of original images of the illuminated chip with dot matrices through the synchronous time-sharing triggering method of the digital micromirror device and the camera. After the super-resolution image reconstruction step, a super-resolution image with high signal-to-noise ratio and twice the wide-field resolution is obtained; the present invention uses a high-speed digital micromirror device and a camera to synchronously trigger time-sharing to achieve multi-focus dot matrix illumination and scanning imaging. Compared with other optical microscopic chip detection imaging methods, this method does not require fluorescence labeling of the chip and can quickly, conveniently and reliably detect super-resolution chip characteristic structures and defects. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0019] Figure 1 It is a flowchart of the super-resolution multi-focus structured light illumination interference scattering microscopy method in the present invention.

[0020] Figure 2 It is a schematic diagram of the optical structure of the system in the present invention.

[0021] Figure 3 It is a schematic diagram of the system scanning imaging control and synchronous trigger signal in the present invention.

[0022] Figure 4 It is a schematic diagram of the wide-field image and the super-resolution image in the present invention.

[0023] Figure 5 It is a functional schematic diagram of the terminal in one implementation manner of the present invention.

[0024] The realization of the object of the present invention, the functional features and advantages will be further described with reference to the embodiments and the accompanying drawings. Specific Embodiments

[0025] In order to make the object, technical solution and advantages of the present invention clearer and more definite, the following further describes the present invention in detail with reference to the accompanying drawings and by way of examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Exemplary Method Currently, common detection methods such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) have been used to detect fine feature structures and defects in semiconductor integrated circuits. However, these imaging technologies have low throughput due to their small field of view or the requirement of high vacuum conditions. Therefore, it is time-consuming to image large sample areas using these technologies. In contrast, optical microscopy is an imaging technology that has a relatively large field of view and does not require a vacuum condition, so it has a high throughput. However, due to the limitation of the Abbe diffraction limit, useful features are submerged in the background and are interfered by different types of errors from the hardware side or the software side, making it almost impossible to see defects from the original optical image, and making it impossible for traditional optical microscopes to accurately evaluate chip feature patterns and tiny defects during imaging. For this reason, a variety of optical microscopy techniques have been developed to improve the detection speed and spatial resolution for chip detection. For example, scatterometry has been widely used in the size measurement of fine patterns on semiconductor chips due to its high measurement speed.

[0027] Although existing scattering measurement methods can capture sub-wavelength periodic structures, they still have limitations when measuring isolated or aperiodic structures. A method for chip defect detection using stochastic optical reconstruction microscopy (STORM) has been proposed. Although it can detect chip defects with an ultra-high lateral resolution of 20 nanometers, it requires fluorescent labeling of the characteristic structures of the chip and the acquisition of thousands or even tens of thousands of images to reconstruct a super-resolution image. The slow imaging speed and difficult labeling make it difficult to apply STORM in actual chip detection.

[0028] To address the above technical problems, in an embodiment of the present invention, a super-resolution multi-focus structured light illumination interference scattering microscopy imaging method is provided. This method uses a digital micromirror device to generate a focused dot matrix for scanning imaging. Compared with the single-point scanning imaging of a confocal microscope, it significantly improves the throughput of chip detection. This solution obtains a series of original illumination images of the chip with dot matrices through the synchronous time-sharing triggering of the digital micromirror device and the camera. After the super-resolution image reconstruction step, a super-resolution image with a high signal-to-noise ratio and twice the wide-field resolution is obtained; in an embodiment of the present invention, a high-speed digital micromirror device and a camera are used for synchronous time-sharing triggering to achieve multi-focus dot matrix illumination and scanning imaging. Compared with other optical microscopy chip detection imaging methods, this method does not require fluorescent labeling of the chip and can quickly, conveniently, and reliably perform super-resolution chip characteristic structure and defect detection.

[0029] As Figure 1 shown, an embodiment of the present invention provides a super-resolution multi-focus structured light illumination interference scattering microscopy imaging method, including the following steps: Step S100, controlling a laser to generate laser light, and collimating and expanding the laser light and then irradiating it on a digital micromirror device.

[0030] In this embodiment, the method is implemented based on a super-resolution multi-focus structured light illumination interference scattering microscopy system; the super-resolution multi-focus structured light illumination interference scattering microscopy system includes: an optical structure part and a system scanning imaging control part.

[0031] Specifically, as Figure 2 shown, the optical structure part includes: a laser (Lasers), a mirror group (mirrors M1, M2), a first 4f system (lenses L1, L2, mirror M3), a digital micromirror device (DMD), a second 4f system (lenses L3, mirror M4, aperture Iris, lens L4), a tube lens L5, a beam splitter, an objective lens (TL), and a camera (Scmos), etc., which are sequentially connected in an optical path.

[0032] Specifically, as Figure 3 shown, Figure 3Figure (a) shows a schematic structure of the system scanning imaging control part, including: a digital acquisition card and a terminal (computer); the laser, the digital micromirror device, the camera, and the digital acquisition card are respectively connected to the terminal, and the digital micromirror device and the camera are separately connected to the digital acquisition card.

[0033] In this embodiment, the basic idea of the method is to use a digital micromirror device (DMD) to generate a multi-focus dot matrix on the basis of using a confocal microscope for single-point scanning of wafer chips for defect detection, so as to perform super-resolution defect detection of wafer chips, thereby improving the detection speed of wafer chips and realizing super-resolution imaging detection of the characteristic patterns and defects of wafer chips.

[0034] Specifically, based on the above super-resolution multi-focus structured light illumination interference scattering microscopy imaging system, the method uses the multi-focus structured light illumination microscopy imaging method to perform super-resolution defect detection of wafer chips; first, the laser is collimated and expanded and then irradiated onto the digital micromirror device.

[0035] Specifically, in one implementation manner of this embodiment, step S100 includes the following steps: Step S101, controlling the laser to emit continuous laser light; Step S102, adjusting the pitch angle of the laser so that the propagation direction of the laser is horizontal with the optical platform, and expanding the laser to obtain the expanded laser; Step S103, reflecting the expanded laser through a reflector so that the laser enters the working surface of the digital micromirror device at a first incident angle.

[0036] In this embodiment, as Figure 2 shown, Laser is a continuous laser, and the pitch angle of the emitted laser is adjusted by two reflectors M1 and M2 so that the propagation direction of the laser is horizontal with the optical platform; then, it is expanded through a 4f system composed of lenses L1 and L2, and the laser after collimation and expansion is reflected by reflector M3 and enters the working surface of the digital micromirror device (DMD) at an incident angle of 24°, and the diameter size of the expanded laser is slightly larger than the diagonal length of the working panel of the digital micromirror device.

[0037] As Figure 1 shown, an embodiment of the present invention provides a super-resolution multi-focus structured light illumination interference scattering microscopy imaging method, including the following steps: Step S200, using the digital micromirror device to modulate the expanded laser and transmitting the modulated laser to the wafer surface to form a multi-focus array illumination pattern on the wafer surface.

[0038] In this embodiment, after the collimated and expanded laser enters the working surface of the digital micromirror device (DMD) at an incident angle of 24°, the laser is modulated by the digital micromirror device to form a dot matrix illumination pattern and transmitted to the surface of the wafer chip; then, the dot matrix illumination information reflected from the surface of the wafer chip is collected by a detector.

[0039] Specifically, in one implementation manner of this embodiment, step S200 includes the following steps: Step S201, control the micro-mirror of the digital micromirror device to remain in the on state, select to allow the laser in a preset area to pass through the subsequent 4f optical path system, and transmit it to the surface of the wafer at a second incident angle, so as to form a multi-focal dot matrix illumination pattern on the surface of the wafer.

[0040] In this embodiment, the digital micromirror device controls the "on" (open) and "off" (closed) states of the micro-mirrors therein, selects to allow the light in a specific area to pass through and enter the subsequent optical path for imaging. By controlling the digital micromirror device, the micro-mirrors at specific positions are kept in the "on" state, and the light beam is modulated into a dot matrix distribution illumination pattern. The micro-mirrors in the "on" state can reflect the light into the 4f system composed of lenses L3 and L4, while the micro-mirrors in the "off" state can reflect the light out of the optical system.

[0041] Furthermore, as Figure 2 shown, in this embodiment, an aperture is placed on the image-side focal plane of lens L3 for spatial filtering, and only the ±1 order diffracted light is allowed to pass through. The light beam modulated by the digital micromirror device forms a sparse multi-focal dot matrix illumination pattern on the rear focal plane of lens L4 after passing through this filtering system, and its position coincides with the front focal plane of the excitation tube lens L5. Finally, the light beam passes through the tube lens L5 and the beam splitter and is transmitted into the objective lens, and finally irradiates the surface of the wafer chip. This imaging method is a bright-field imaging method, and the dot matrix illumination pattern irradiates the surface of the wafer chip at a large angle (for example, perpendicular 90°), the reflected light directly enters the objective lens and is collected, then is reflected by the beam splitter again, and finally is imaged on the sCMOS camera through the tube lens TL.

[0042] It is worth mentioning that in Figure 2 the optical system shown, the following aspects need to be noted during the adjustment process: (1) The beam expansion ratio of the beam expansion system composed of lenses L1 and L2 needs to be appropriately selected according to the size of the light source, that is, the diameter of the expanded light beam should be slightly larger than the used area of the display panel of the digital micromirror device, so as to make the best use of the excitation illumination intensity.

[0043] (2) According to the working principle of the digital micromirror device, the incident light needs to irradiate the surface of the digital micromirror device at a specific angle of 24°. Only at this angle can the outgoing light be emitted perpendicular to the surface of the digital micromirror device, so as to obtain the best effect. If the incident angle deviates from the set angle, it will lead to the distortion of the excitation mode.

[0044] (3) Since the surface of the digital micromirror device needs to maintain a conjugate relationship with the sample surface (the surface of the wafer chip), during the setup process, special attention should be paid to the placement position of the digital micromirror device and the arrangement of the lens group. If the digital micromirror device fails to maintain conjugation with the sample surface, the focused spot finally formed on the sample surface will be enlarged, thus affecting the imaging resolution of the system.

[0045] As Figure 1 shown, the embodiment of the present invention provides a super-resolution multi-focus structured light illumination interference scattering microscopy imaging method, including the following steps: Step S300, collecting multi-focus information reflected from the surface of the wafer by a camera, and loading the multi-focus information into the illumination template of the digital micromirror device to realize the scanning imaging detection of the entire surface of the wafer.

[0046] In this embodiment, based on the above optical structure system, the schematic diagram of realizing the scanning imaging control of the optical structure system is as Figure 3 shown. In order to perform scanning imaging of the illumination dot matrix on the surface of the wafer chip, the required control terminal is as Figure 3 shown in (a) therein; the scanning imaging control process of this control terminal is mainly to collect multi-focus information reflected from the surface of the wafer by a camera, and then load the multi-focus information into the illumination template of the digital micromirror device.

[0047] Specifically, in an implementation manner of this embodiment, step S300 includes the following steps: Step S301, collecting multi-focus information reflected from the surface of the wafer by the camera; Step S302, loading the multi-focus information into multiple black-and-white dot matrix pictures, so that each white pixel in each black-and-white dot matrix picture corresponds to a focus point on the surface of the wafer; Step S303, switching the display mode according to the order of the loaded black-and-white dot matrix pictures, controlling the movement of the focus points on the surface of the wafer until the entire surface of the wafer within the field of view is scanned.

[0048] In this embodiment, the specific implementation method of the scanning imaging control is as follows: (1) A series of black-and-white dot matrix pictures need to be pre-loaded into the digital micromirror device control software of the computer, that is, before collecting the multi-focus information reflected from the surface of the wafer through the camera, multiple black-and-white dot matrix pictures are loaded into the digital micromirror device; during the process of loading each black-and-white dot matrix picture, each white pixel corresponds to a focus point on the surface of the wafer chip. When the digital micromirror device starts to switch the display mode according to the order of the loaded pictures, the focus points on the surface of the wafer chip will move until the entire surface of the wafer chip within the field of view is scanned.

[0049] (2) While the digital micromirror device switches pictures, the camera simultaneously performs an exposure to synchronously collect dot matrix images. In order to synchronize the scanning and camera collection, it is necessary to use Labview software to control the digital acquisition card to generate two-way synchronous trigger signals, as Figure 3 shown in (b) of Figure 3 (b) in

[0050] is a schematic diagram of the synchronous trigger signal of the digital acquisition card. The two signals have the same initial phase and frequency. Whenever the digital micromirror device receives a new rising edge signal, it will read a new dot matrix picture from the memory to replace the original display mode, thereby changing the excitation position of the focus points on the sample surface. At the same time, the camera will end the previous collection and immediately enter a new exposure under the action of the trigger signal.

[0051] As Figure 1 shown, the embodiment of the present invention provides a super-resolution multi-focus structured light illumination interference scattering microscopy imaging method, which further includes the following steps: Step S400, performing image reconstruction on a number of original dot matrix image data detected by scanning imaging to obtain a super-resolution image of the wafer characteristic structure.

[0052] In this embodiment, the Labview is used to control the data acquisition card to generate two-way synchronous trigger signals, so that each time the digital micromirror device switches a template, the camera performs a synchronous collection until the entire surface of the chip is scanned and imaged; then, after pixel repositioning and deconvolution of a series of dot matrix pictures collected by the camera, a super-resolution image can be obtained.

[0053] Specifically, in one implementation manner of this embodiment, step S400 includes the following steps: Step S401: Perform pinhole filtering on a number of original dot matrix image data obtained from scanning imaging detection; Step S402: Relocate the pixels in the dot matrix image data after pinhole filtering; Step S403: Process the image after pixel relocation based on the deconvolution algorithm to obtain the super-resolution image of the wafer feature structure.

[0054] In this embodiment, the steps for reconstructing the super-resolution image of this technology are as follows: (1) Denoising processing: Perform pinhole filtering on the collected dot matrix data to reduce the crosstalk between illuminated dots and background noise, and improve the accuracy of subsequent reconstruction.

[0055] (2) Pinhole filtering: Locate the positions of all the reflected dot matrix information of the wafer chips, and add digital pinholes to filter out the excessive reflected light intensity around all the excitation points (illuminated light points) in each dot matrix image through the digital pinholes.

[0056] (3) Pixel relocation: Correct the offset of the signal reflected by the wafer chips on the detection surface, and obtain a super-resolution image with a resolution increased by times compared to wide-field illumination.

[0057] (4) Deconvolution algorithm: Use the R-L deconvolution algorithm to process the image after pixel relocation, and finally obtain a high-signal-to-noise-ratio super-resolution image with a resolution improvement of approximately 2 times compared to wide-field illumination imaging, that is, obtain a high-signal-to-noise-ratio super-resolution image of the chip feature structure.

[0058] In this embodiment, a series of original images of the illuminated chips in the form of dot matrices are obtained through the synchronous time-sharing triggering of the digital micromirror device and the camera. After the above-mentioned super-resolution image reconstruction steps, a super-resolution image with a high signal-to-noise ratio and twice the wide-field resolution is obtained. As Figure 4 shown, Figure 4 in (a) is a low-signal-to-noise-ratio and low-resolution picture of the chip obtained using wide-field illumination, Figure 4 in (b) is a high-signal-to-noise-ratio and high-resolution picture of the chip obtained using multi-focus illumination super-resolution reconstruction. Therefore, the method provided in this embodiment helps to break through the diffraction limit of the optical microscope and achieve the detection of finer chip surface defects and microstructures.

[0059] It is worth mentioning that in this embodiment, in order to meet the detection requirements of wafer chips in different scenarios, the parameters of the used laser can be modified to obtain different imaging effects. For example, when the optical wavelength of the used laser is visible light (below 700 nm), the resolution is high and the penetration ability is weak. Using light of this wavelength is suitable for microscopic detection of the chip surface, including surface defects, particles, and super-resolution imaging of surface microstructures. Another example is that when the optical wavelength of the used laser is near-infrared light (in the range of 700 nm to several micrometers), the resolution is low and the penetration ability is strong. Using light of this wavelength is suitable for super-resolution detection of the internal structure and defects of the chip, and this imaging method has a certain compensation effect on the low resolution of near-infrared light detection. All these improvements and transformations should fall within the protection scope of the technical solution in this embodiment.

[0060] This embodiment achieves the following technical effects through the above technical solutions: The multi-focus structured illumination microscopy proposed in this embodiment is a parallel method for chip detection using a confocal microscope. This method uses a digital micromirror device to generate a focused dot matrix for scanning imaging. Compared with the single-point scanning imaging of a confocal microscope, it greatly improves the throughput of chip detection. This solution obtains a series of original images of the illuminated chip with dot matrices through the synchronous time-sharing triggering method of the digital micromirror device and the camera. After the super-resolution image reconstruction step, a super-resolution image with high signal-to-noise ratio and twice the wide-field resolution is obtained. This embodiment uses a high-speed digital micromirror device and a camera to synchronously trigger time-sharing to achieve multi-focus dot matrix illumination and scanning imaging. Compared with other optical microscopic chip detection imaging methods, this method does not require fluorescence labeling of the chip and can quickly, conveniently, and reliably perform super-resolution detection of chip characteristic structures and defects.

[0061] Exemplary device Based on the above embodiment, the present invention further provides a super-resolution multi-focus structured light illumination interference scattering microscopy imaging system, including: A laser, a mirror group, a first 4f system, a digital micromirror device, a second 4f system, a tube lens, a beam splitter, an objective lens, and a camera that are sequentially connected in an optical path; The system further includes: a digital acquisition card and a terminal; the laser, the digital micromirror device, the camera, and the digital acquisition card are respectively connected to the terminal, and the digital micromirror device and the camera are separately connected to the digital acquisition card; The terminal is used to implement the following steps: Control the laser to generate laser light, and irradiate the laser light on the digital micromirror device after collimation and beam expansion; Use the digital micromirror device to modulate the expanded laser light and transmit the modulated laser light to the wafer surface to form a multi-focus dot matrix illumination pattern on the wafer surface; Collect multi - focus information reflected from the surface of the wafer through a camera, and load the multi - focus information into the illumination template of the digital micromirror device to achieve scanning imaging detection of the entire wafer surface; Perform image reconstruction on a number of original dot - matrix image data obtained from the scanning imaging detection to obtain a super - resolution image of the wafer characteristic structure.

[0062] Through the above - mentioned technical solution, this embodiment achieves the following technical effects: The multi - focus structured - light illumination microscope proposed in this embodiment is a parallel method for chip detection using a confocal microscope. This method uses a digital micromirror device to generate a focused dot - matrix for scanning imaging. Compared with the single - point scanning imaging of a confocal microscope, it greatly improves the throughput of chip detection. This solution obtains a series of original images of the illuminated chip in the form of dot - matrices through the synchronous time - sharing triggering of the digital micromirror device and the camera. After the super - resolution image reconstruction step, a super - resolution image with high signal - to - noise ratio and twice the wide - field resolution is obtained. This embodiment uses a high - speed digital micromirror device and a camera to synchronously trigger in time - sharing to achieve multi - focus dot - matrix illumination and scanning imaging. Compared with other optical microscopic chip detection imaging methods, this method does not require fluorescence labeling of the chip and can quickly, conveniently, and reliably perform super - resolution chip characteristic structure and defect detection.

[0063] Based on the above - mentioned embodiment, the present invention also provides a terminal, and its principle block diagram can be as Figure 5 shown.

[0064] The terminal includes: a processor, a memory, an interface, a display screen, and a communication module connected through a system bus; wherein, the processor of the terminal is used to provide computing and control capabilities; the memory of the terminal includes a storage medium and an internal memory; the storage medium stores an operating system and a computer program; the internal memory provides an environment for the operation of the operating system and the computer program in the storage medium; the interface is used to connect external devices; the display screen is used to display corresponding information; the communication module is used to communicate with a cloud server or other devices.

[0065] When the computer program is executed by the processor, it is used to implement the operations of the super - resolution multi - focus structured - light illumination interference scattering microscopy imaging method.

[0066] Those skilled in the art can understand that Figure 5 the principle block diagram shown in

[0067] In one embodiment, a terminal is provided, which includes: a processor and a memory. The memory stores a super-resolution multi-focus structured light illumination interference scattering microscopy program. When the super-resolution multi-focus structured light illumination interference scattering microscopy program is executed by the processor, it is used to implement the operations of the super-resolution multi-focus structured light illumination interference scattering microscopy method as described above.

[0068] In one embodiment, a storage medium is provided, which stores a super-resolution multi-focus structured light illumination interference scattering microscopy program. When the super-resolution multi-focus structured light illumination interference scattering microscopy program is executed by the processor, it is used to implement the operations of the super-resolution multi-focus structured light illumination interference scattering microscopy method as described above.

[0069] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database or other medium used in the embodiments provided by the present invention can include non-volatile and volatile memories.

[0070] In summary, the present invention provides a super-resolution multi-focus structured light illumination interference scattering microscopy method and system, including: controlling a laser to generate laser light, collimating and expanding the laser light and then irradiating it on a digital micromirror device; using the digital micromirror device to modulate the expanded laser light and transmitting the modulated laser light to the surface of a wafer to form a multi-focus array illumination pattern on the wafer surface; collecting multi-focus information reflected from the wafer surface through a camera and loading the multi-focus information into the illumination template of the digital micromirror device to achieve scanning imaging detection of the entire wafer surface; performing image reconstruction on a number of original dot matrix image data obtained from the scanning imaging detection to obtain a super-resolution image of the wafer characteristic structure. The present invention uses a high-speed digital micromirror device and a camera to synchronously trigger in a time-sharing manner to achieve multi-focus dot matrix illumination and scanning imaging, without performing fluorescence labeling of the chip, and can quickly, conveniently and reliably detect super-resolution chip characteristic structures and defects.

[0071] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A super-resolution multi-focus structured light illumination interference scattering microscopy imaging method for wafer defect detection, characterized in that: include: Controlling the laser to generate laser light, and irradiating the laser light onto the digital micromirror device after collimation and beam expansion; Using the digital micromirror device to modulate the beam-expanded laser, and transmitting the modulated laser to the wafer surface, so as to form a multi-focal array illumination mode on the wafer surface; Collecting multi-focus information reflected from the wafer surface by a camera, and loading the multi-focus information into the illumination template of the digital micromirror device to achieve scanning imaging detection of the entire wafer surface; Image reconstruction is performed on a number of original dot matrix image data detected by scanning imaging to obtain a super-resolution image of the wafer characteristic structure.

2. The super-resolution multi-focus structured light illumination interference scattering microscopy imaging method according to claim 1, characterized in that: The method of controlling the laser to generate laser light and irradiating the laser light on the digital micromirror device after collimation and beam expansion includes: Controlling the laser to emit continuous laser light; Adjusting the pitch angle of the laser so that the propagation direction of the laser is kept horizontal with the optical platform, and expanding the laser to obtain an expanded laser; The beam-expanded laser is reflected by a reflector, so that the laser enters the working surface of the digital micromirror device at a first incident angle.

3. The super-resolution multi-focus structured light illumination interference scattering microscopy imaging method according to claim 1, characterized in that: The diameter of the expanded laser beam is greater than the diagonal length of the working panel of the digital micromirror device.

4. The super-resolution multi-focus structured light illumination interference scattering microscopy imaging method according to claim 1, characterized in that: The method of using the digital micromirror device to modulate the expanded laser beam and transmitting the modulated laser beam to the wafer surface to form a multi-focal array illumination mode on the wafer surface includes: The digital micromirror device is used to control the micromirror to remain in an on state, and the laser in a preset area is selected to pass through the subsequent 4f optical path system and is transmitted to the wafer surface at a second incident angle to form a multi-focal array illumination mode on the wafer surface.

5. The super-resolution multi-focus structured light illumination interference scattering microscopy imaging method according to claim 1, characterized in that: The method of collecting the multi-focal information reflected from the wafer surface by a camera and loading the multi-focal information into the illumination template of the digital micromirror device comprises: A plurality of black and white dot matrix images are loaded into the digital micromirror device.

6. The super-resolution multi-focus structured light illumination interference scattering microscopy imaging method according to claim 5, characterized in that: The method collects multi-focus information reflected from the wafer surface by a camera, and loads the multi-focus information into the illumination template of the digital micromirror device to realize scanning imaging detection of the entire wafer surface, including: Collecting multi-focus information reflected from the wafer surface by the camera; Loading the multi-focus information onto a plurality of the black-and-white dot matrix images so that each white pixel in each of the black-and-white dot matrix images corresponds to a focus point on the wafer surface; The display mode is switched according to the sequence of the loaded black and white dot matrix images, and the focus point on the wafer surface is controlled to move until the entire wafer surface within the field of view is scanned.

7. The super-resolution multi-focus structured light illumination interference scattering microscopy imaging method according to claim 1, characterized in that: The image reconstruction of a plurality of original dot matrix image data detected by scanning imaging to obtain a super-resolution image of the wafer characteristic structure includes: Perform pinhole filtering on a number of original dot matrix image data detected by scanning imaging; Repositioning pixels in the dot matrix image data after pinhole filtering; The image after pixel relocation is processed based on a deconvolution algorithm to obtain a super-resolution image of the wafer characteristic structure.

8. A super-resolution multi-focus structured light illumination interference scattering microscopy imaging system, characterized in that: include: A laser, a reflector group, a first 4f system, a digital micromirror device, a second 4f system, a tube lens, a beam splitter, an objective lens and a camera connected in an optical path are sequentially formed; The system further comprises: a digital acquisition card and a terminal; the laser, the digital micromirror device, the camera and the digital acquisition card are connected to the terminal respectively, and the digital micromirror device and the camera are connected to the digital acquisition card separately; The terminal is used to implement the following steps: Controlling the laser to generate laser light, and irradiating the laser light onto the digital micromirror device after collimation and beam expansion; Using the digital micromirror device to modulate the beam-expanded laser, and transmitting the modulated laser to the wafer surface, so as to form a multi-focal array illumination mode on the wafer surface; Collecting multi-focus information reflected from the wafer surface by a camera, and loading the multi-focus information into the illumination template of the digital micromirror device to achieve scanning imaging detection of the entire wafer surface; Image reconstruction is performed on a number of original dot matrix image data detected by scanning imaging to obtain a super-resolution image of the wafer characteristic structure.

9. A terminal, characterized in that: include: A processor and a memory, wherein the memory stores a super-resolution multi-focus structured light illumination interferometer scattering microscopy imaging program, and when the super-resolution multi-focus structured light illumination interferometer scattering microscopy imaging program is executed by the processor, it is used to implement the operation of the super-resolution multi-focus structured light illumination interferometer scattering microscopy imaging method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a super-resolution multi-focus structured light illumination interference scattering microscopy imaging program, which, when executed by a processor, is used to implement the operation of the super-resolution multi-focus structured light illumination interference scattering microscopy imaging method as described in any one of claims 1 to 7.

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