Sub-micron foreign matter nondestructive detection device and sub-micron foreign matter nondestructive detection method

Abstract

The present disclosure relates to the technical field of laser optical detection, and provides a sub-micron foreign matter nondestructive detection device and a sub-micron foreign matter nondestructive detection method. The device comprises a moving carrier, a mid-infrared laser, a laser vibration detector and a signal processing module. The mid-infrared laser is used for emitting mid-infrared laser beams of different wavelengths to a sample to be detected. The signal processing module is electrically connected with the laser vibration detector and is used for receiving and processing the measurement signals of the laser vibration detector. After the detection laser irradiates the sample to be detected, the detection laser can be reflected, refracted or scattered back to the laser vibration detector. The photodetector is used for detecting the interference frequency difference of the combined laser beams and converting the interference frequency difference into an electrical signal of the vibration of the sample to be detected. The method can realize rapid detection of sub-micron foreign matters on the surface of the sample to be detected, and the sample to be detected is not damaged in the whole detection process, and the method can be applied to online detection of the sample to be detected in a pipeline.

Description

Technical Field

[0001] This disclosure relates to the field of laser optical inspection technology, and in particular to a submicron-level foreign object nondestructive testing device and a submicron-level foreign object nondestructive testing method. Background Technology

[0002] Integrated circuits, discrete devices, sensors, optoelectronic devices, and other fields involving micro-nano manufacturing and related devices involve the application, fabrication, and removal processes of a large number of submicron-sized materials. Improper management and removal of non-functional foreign matter introduced during manufacturing due to material and environmental factors can affect the functionality and reliability of device applications, making it a critical factor requiring strict control in the process. Furthermore, with the continuous development and refinement of micro-nano fabrication processes, the requirements for controlling the type, size, and quantity of foreign matter are becoming increasingly stringent.

[0003] Currently, in the fabrication process of micro and nano devices, purely optical and visual methods are commonly used to detect foreign objects and defects, often achieving only micrometer-level resolution. In the analysis of foreign objects in devices already determined to be faulty, specific disassembly is often required, employing techniques such as micro-infrared spectroscopy for chemical composition analysis, electron microscopy for high-resolution surface morphology and size detection, X-ray energy dispersive spectroscopy for elemental composition analysis of organic matter, atomic force microscopy for measuring the size and surface roughness of organic matter, X-ray photoelectron spectroscopy for chemical composition and bonding state analysis of organic matter, and ellipsometry for measuring the thickness and optical properties of organic matter. Due to limitations in resolution, sensitivity, device (wafer) inspection adaptability, and inspection timeliness, these techniques cannot achieve rapid, non-destructive testing of sub-micrometer-level foreign objects during fabrication.

[0004] In view of this, there is an urgent need in the market for a new type of non-destructive testing device and method for micro and nano foreign objects, in order to solve the problem that existing micro and nano devices cannot achieve rapid non-destructive testing of submicron-level foreign objects during the fabrication process. Summary of the Invention

[0005] This disclosure provides a submicron-level foreign object nondestructive testing device and method to solve the problem that existing micro-nano devices cannot achieve rapid nondestructive testing of submicron-level foreign objects during the fabrication process.

[0006] The submicron-level foreign object nondestructive testing device provided in this embodiment includes a moving stage, a mid-infrared laser, a laser vibrometer, and a signal processing module;

[0007] The mobile stage is capable of moving the sample to be tested in multiple different directions;

[0008] The mid-infrared laser is used to emit mid-infrared lasers of different wavelengths toward the sample to be tested;

[0009] The laser vibration meter includes a beam splitter, a beam combiner, and a photodetector sequentially arranged in its own optical path;

[0010] The signal processing module is electrically connected to the laser vibrometer and is used to receive and process the measurement signals from the laser vibrometer.

[0011] The beam splitter can split the laser beam emitted by the laser vibrometer into a probe laser and a reference laser, and the probe laser can be reflected, refracted or scattered back to the laser vibrometer after irradiating the sample under test.

[0012] The beam combiner is used to combine the reference laser with the probe laser that is reflected, refracted, or scattered back.

[0013] The photodetector is used to detect the frequency difference of the combined laser interference and convert it into an electrical signal of the vibration of the sample under test.

[0014] In one embodiment, the mid-infrared laser is capable of irradiating the sample to be tested with the mid-infrared laser light through a first optical path;

[0015] The first optical path is provided with a first dichroic mirror, a second dichroic mirror and a reflecting objective lens arranged sequentially at intervals along the illumination direction;

[0016] The mid-infrared laser can penetrate the first dichroic mirror and the second dichroic mirror respectively;

[0017] The probe laser can be reversed and reflected onto the sample under test by the second dichroic mirror, or reversed and reflected back to the laser vibrometer.

[0018] The reflecting objective is used to focus the mid-infrared laser and the detection laser onto the surface of the sample to be tested.

[0019] In one possible implementation, it further includes a focusing lens and a photosensitive coupling assembly disposed corresponding to the first dichroic mirror;

[0020] The sample under test can partially reflect the mid-infrared laser back to the first dichroic mirror along the first optical path, and the first dichroic mirror can reflect the reflected mid-infrared laser back to the focusing lens;

[0021] The focusing lens is used to focus the mid-infrared laser reflected by the first dichroic mirror onto the photosensitive coupling component.

[0022] In one embodiment, the laser vibrometer further includes a helium-neon laser and an acousto-optic modulator;

[0023] The helium-neon laser is used to emit laser light toward the beam splitter, and the beam splitter serves as both a probe laser and a reference laser.

[0024] The reference laser is irradiated onto the beam combiner after passing through the acousto-optic modulator.

[0025] In one possible implementation, the signal processing module includes a lock-in amplifier and a processor;

[0026] The lock-in amplifier is electrically connected to the photodetector and is used to lock the signal vibration measured by the photodetector.

[0027] The processor is electrically connected to the lock-in amplifier and can draw a vibration intensity image based on the lock-in data of the lock-in amplifier.

[0028] In one embodiment, the processor is also electrically connected to the mid-infrared laser and is capable of controlling the mid-infrared laser to output multiple equally spaced wavelengths of mid-infrared laser light one by one.

[0029] In one embodiment, the processor is also electrically connected to the mobile platform and can control the mobile platform to scan and move along a preset trajectory path and a preset speed.

[0030] In addition, this disclosure also provides a submicron-level foreign object nondestructive testing method, applicable to the aforementioned submicron-level foreign object nondestructive testing device, which includes the following steps:

[0031] The first step is to fix the sample to be tested on the moving stage and adjust the moving stage so that the sample to be tested is accurately located in the detection focus area.

[0032] The second step involves emitting a probe laser to the sample under test using a laser vibrometer. Based on the optical imaging image of the laser vibrometer, the signal processing module selects the boundary of the area to be detected in the sample and generates the moving scanning and filling path of the moving stage.

[0033] The third step involves emitting a repetitive frequency of mid-infrared laser light from a mid-infrared laser onto the sample under test, and selecting multiple equally spaced wavelengths within the spectral range of the mid-infrared laser to output them one by one. At each wavelength, the laser vibrometer performs a detection task one by one, and the signal processing module plots a vibration intensity distribution image based on the multiple wavelengths of the mid-infrared laser.

[0034] In one embodiment, the submicron-level nondestructive testing method for foreign objects further includes:

[0035] The follow-up inspection step involves adjusting the wavelength of the mid-infrared laser emitted by the selected mid-infrared laser based on the peaks in the vibration intensity distribution image, and then randomly selecting other locations on the sample to be tested for area detection or full-area detection.

[0036] In one embodiment, the submicron-level nondestructive testing method for foreign objects further includes:

[0037] The foreign matter composition analysis step involves setting the scanning output period of the mid-infrared laser and recording the signal intensity spectrum drawn by the mid-infrared laser through a lock-in amplifier to obtain the wavelength of the vibration peak position of the foreign matter material. Based on the position of the infrared absorption fingerprint peak of common chemical bonds, the composition of the foreign matter material is analyzed and determined.

[0038] The technical solution provided in this disclosure has the following advantages compared with the prior art:

[0039] The submicron-level non-destructive testing device for foreign objects provided in this embodiment can detect submicron-level foreign objects on the surface of the sample to be tested. Moreover, the entire testing process is non-destructive to the sample to be tested and does not require any additional pre-test processing such as cutting or extraction. It is suitable for online testing of samples on a production line and has the beneficial effects of high detection precision, fast detection efficiency, and the ability to quickly detect and evaluate foreign objects on the surface of large-size devices.

[0040] Furthermore, the submicron-level foreign object nondestructive testing method provided in this disclosure can be applied to the aforementioned submicron-level foreign object nondestructive testing device, and can achieve the same beneficial effects.

[0041] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0042] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which:

[0043] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0044] Figure 1 A schematic diagram of the submicron-level foreign object nondestructive testing device provided in this embodiment of the present disclosure is shown;

[0045] Figure 2 The infrared photothermal vibration intensity spectrum of the submicron-level foreign object non-destructive testing device provided in this embodiment of the present disclosure is shown.

[0046] Figure 3 A flowchart of a submicron-level nondestructive testing method for foreign objects provided in an embodiment of this disclosure is shown.

[0047] Explanation of the labels in the diagram: 1. Moving platform;

[0048] 2. Mid-infrared laser; 111. Reflector; 101. Beam splitter; 102. Beam combiner; 103. Half-wave plate; 104. Polarizer;

[0049] 3. Laser vibrometer; 31. Helium-neon laser; 32. Beam splitter; 33. Beam combiner; 34. Photodetector; 35. Acousto-optic modulator;

[0050] 4. Signal processing module; 41. Lock-in amplifier; 42. Processor;

[0051] 5. Photosensitive coupling assembly; 51. Focusing lens. Detailed Implementation

[0052] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0053] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0054] Combination Figure 1 As shown, this embodiment of the present disclosure provides a submicron-level nondestructive testing device for foreign objects, which includes a movable stage 1, a mid-infrared laser 2, a laser vibrometer 3, and a signal processing module 4; the movable stage 1 is capable of moving the sample to be tested along multiple different directions; the mid-infrared laser 2 is used to emit mid-infrared lasers of different wavelengths to the sample to be tested; the laser vibrometer 3 includes a beam splitter 32, a beam combiner 33, and a photodetector 34 sequentially arranged in its own optical path; the signal processing module 4 is electrically connected to the laser vibrometer 3 and is used to receive and process the measurement signals of the laser vibrometer 3;

[0055] Among them, the beam splitter 32 can split the laser emitted by the laser vibrometer 3 into a probe laser and a reference laser, and the probe laser can be reflected, refracted or scattered back to the laser vibrometer 3 after irradiating the sample under test; the beam combiner 33 is used to combine the reference laser with the reflected, refracted or scattered probe laser; the photodetector 34 is used to detect the interference frequency difference of the combined laser and convert it into an electrical signal of the vibration of the sample under test.

[0056] In one embodiment, the mid-infrared laser 2 can irradiate the sample to be tested with mid-infrared laser light through a first optical path; a first dichroic mirror 21, a second dichroic mirror 22, and a reflecting objective 23 are arranged sequentially and at intervals along the irradiation direction in the first optical path; the mid-infrared laser light can pass through the first dichroic mirror 21 and the second dichroic mirror 22 respectively; the probe laser light can be reversed and reflected onto the sample to be tested through the second dichroic mirror 22, or reversed and reflected back to the laser vibrometer 3; the reflecting objective 23 is used to focus the mid-infrared laser light and the probe laser light onto the surface of the sample to be tested.

[0057] In one embodiment, the device further includes a focusing lens 51 and a photosensitive coupling component 5, which are disposed corresponding to the first dichroic mirror 21. The sample under test can partially reflect the mid-infrared laser back to the first dichroic mirror 21 along the first optical path, and the first dichroic mirror 21 can reflect the reflected mid-infrared laser back to the focusing lens 51. The focusing lens 51 is used to focus the mid-infrared laser reflected by the first dichroic mirror 21 onto the photosensitive coupling component 5.

[0058] A dichroic mirror, also known as a bicolor mirror, can transmit light of a certain wavelength almost completely while reflecting light of other wavelengths almost completely.

[0059] In one embodiment, the laser vibrometer 3 further includes a helium-neon laser 31 and an acousto-optic modulator 35; the helium-neon laser 31 is used to emit laser towards the beam splitter 32, and the beam splitter 32 serves as a probe laser and a reference laser; the reference laser is irradiated onto the beam combiner 33 after passing through the acousto-optic modulator 35.

[0060] In one embodiment, the signal processing module 4 includes a lock-in amplifier 41 and a processor 42; the lock-in amplifier 41 is electrically connected to the photodetector 34 and is used to lock the signal vibration measured by the photodetector 34; the processor 42 is electrically connected to the lock-in amplifier 41 and can draw a vibration intensity image based on the lock-in data of the lock-in amplifier 41.

[0061] In one embodiment, the processor 42 is also electrically connected to the mid-infrared laser 2 and is able to control the mid-infrared laser 2 to output multiple equally spaced mid-infrared lasers one by one.

[0062] In one embodiment, the processor 42 is also electrically connected to the mobile platform 1 and can control the mobile platform 1 to scan and move along a preset trajectory path and a preset speed.

[0063] This submicron-level non-destructive testing device can be applied, but is not limited to, to the rapid non-destructive testing and evaluation analysis of submicron-level foreign objects on the surface of micro-nano devices, precision instruments, silicon wafers, etc. Moreover, the testing process is non-destructive to the sample and does not require any additional pre-test processing such as cutting, extraction, or surface treatment of the sample.

[0064] Specifically, the process of using silicon wafers with submicron-level photoresist residues or silicon carbide crystal wafers as examples will be explained in detail.

[0065] Before testing silicon wafers, silicon carbide crystal wafers, and other samples, this submicron-level non-destructive testing device first prepares the samples for testing. The samples are fixedly placed in the moving stage 1, which can be specifically configured as a three-axis precision electrically controlled displacement stage. By controlling the moving stage 1 to move precisely along the X and Y axes, the samples are moved to be directly below the focusing lens 51. Then, the moving stage 1 is slowly moved along the Z axis to lift the samples until they are located at the focal point of the focusing lens 51. In other words, the surface of the samples can be clearly imaged by the camera.

[0066] Next, the laser vibrometer 3 is turned on and its probe laser is focused onto the surface of the sample to be tested. The optimal position where the probe laser is focused precisely on the sample surface is determined based on the intensity of the laser energy reflected back to the laser vibrometer 3 by the second dichroic mirror 22. Then, based on the optical imaging image, the size and boundary of the area to be detected on the sample surface are selected and imported into the control program of the moving stage 1 via the signal processing module 4. This generates the moving scanning and filling path of the moving stage 1, and the actual scanning speed of the moving stage 1 is set, specifically between 0.1 mm / s and 100 mm / s.

[0067] Then, the mid-infrared laser 2 is turned on and pulsed at a certain repetition frequency, specifically between 10kHz and 1000kHz. The mid-infrared laser is a broadband laser source with a wavelength range of 0.8m to 10m, and the output power at a single wavelength is typically between 3mW and 300mW. The mid-infrared laser is also focused by the focusing lens 51 at the same position as the detection laser focus. Then, multiple wavelengths at equal intervals are selected from the infrared spectrum of the mid-infrared laser and output sequentially. At each wavelength, the moving stage 1 performs the detection task point by point. The specific detection process is as follows: the moving stage 1 scans the entire detection area point by point along a preset path and speed. During the scanning process, the signal reflected back from the detection laser in the laser vibrometer 3 interferes with the reference laser. Based on the Doppler effect, the laser vibrometer function can accurately measure the vibration displacement and velocity of the sample in that area, with a measurement accuracy reaching sub-picometer levels. Vibration data for every point in the entire detection area can be obtained after each detection task.

[0068] The data from the laser vibrometer 3 is then imported into the lock-in amplifier 41. The lock-in amplifier 41 locks the signal according to the frequency of the mid-infrared laser source, thereby obtaining the vibration intensity signal at each detection point at that frequency. The signal processing module 4 then stitches the signals together point by point to create an image of the vibration intensity within the entire detection area. When the probe laser irradiates the surface of the sample under test, and there are no foreign objects present, the photothermal vibration intensity spectrum is... Figure 2 In state a, when there is a foreign object, the photothermal vibration intensity spectrum is as follows: Figure 2 In the b state, and when the size of the foreign object is different, the intensity in the photothermal intensity spectrum is different.

[0069] Because the composition of the foreign object is unclear, among multiple mid-infrared laser wavelengths, if the foreign material strongly absorbs a particular wavelength, it will generate significant thermal vibrations under the photothermal effect. The frequency of these thermal vibrations is the same as the frequency of the mid-infrared laser. Therefore, if an area with significantly increased vibration intensity appears in the image from the detection task, it indicates the presence of a foreign object in that area. The foreign object significantly absorbs the mid-infrared laser, thus causing thermal vibrations. Based on the images scanned at each mid-infrared laser wavelength, the infrared absorption wavelength of the foreign material can be determined, and this wavelength is selected for subsequent detection. Finally, the mid-infrared laser is adjusted to the selected wavelength, and the detection area on the sample is further selected. Two modes can be selected for comprehensive detection of foreign objects: random area detection and full-area detection.

[0070] Furthermore, this submicron-level non-destructive testing device for foreign objects can also be used for the detection and analysis of foreign object composition. In the area where the foreign object is identified, the moving stage 1 is controlled to move, bringing the foreign object to the focal point of the detection laser. The position of the moving stage 1 is then fixed, and measurements are taken at that point. Then, the beam interval and time interval of the mid-infrared laser are set to progressively scan the output. The energy of the mid-infrared laser remains constant under a single wavelength. The signal intensity spectrum under the mid-infrared laser wavelength scan is recorded using a lock-in amplifier 41, thereby obtaining the wavelength of the vibrational peak position of the foreign object material. Finally, based on the position of the infrared absorption fingerprint peaks of common chemical bonds, the composition of the foreign object material is analyzed and determined.

[0071] Furthermore, before testing the sample, a dielectric film that does not degrade the sample surface can be applied to the surface of the sample to enhance the detection signal.

[0072] In summary, the submicron-level non-destructive testing device for foreign objects provided in this embodiment does not damage the sample during the entire testing process and does not require any additional pre-test processing such as cutting or extraction of the sample. It is suitable for online testing of samples on a production line and can detect foreign objects as small as 2nm with a detection efficiency of 10 minutes / 1mm*1mm, thereby enabling rapid detection and evaluation analysis of foreign objects on the surface of large-size devices.

[0073] In addition, such as Figure 3 As shown, this disclosure also provides a submicron-level foreign object nondestructive testing method, applicable to the aforementioned submicron-level foreign object nondestructive testing device, which includes the following steps:

[0074] The first step is to fix the sample to be tested on the moving stage 1 and adjust the moving stage 1 so that the sample to be tested is accurately located in the detection focus area.

[0075] In the second step, the laser vibrometer 3 emits a probe laser to the sample under test. The signal processing module 4 selects the boundary of the area to be detected in the sample based on the optical imaging image of the laser vibrometer 3 and generates the moving scanning filling path of the moving stage 1.

[0076] In the third step, the mid-infrared laser 2 emits a repetitive frequency of mid-infrared laser light onto the sample under test, and selects multiple wavelengths at equal intervals within the spectral range of the mid-infrared laser to output them one by one. At each wavelength, the laser vibration meter 3 runs the detection task one by one, and the signal processing module 4 draws a vibration intensity distribution image based on the multiple wavelengths of the mid-infrared laser.

[0077] In one embodiment, the submicron-level nondestructive testing method for foreign objects further includes:

[0078] In the preparatory step before the first step, a dielectric film is applied to the surface of the sample to be tested to enhance the response sensitivity to the probe laser.

[0079] In the follow-up inspection step after the third step, the wavelength of the mid-infrared laser emitted by the selected mid-infrared laser 2 is adjusted according to the peak in the vibration intensity distribution image, and random area detection or full-area detection is performed on other positions of the sample to be tested.

[0080] In one embodiment, the submicron-level nondestructive testing method for foreign objects further includes:

[0081] In the foreign matter composition analysis step, the scanning output cycle of the mid-infrared laser 2 is set, and the signal intensity spectrum drawn by the mid-infrared laser is recorded by the lock-in amplifier 41 to obtain the wavelength of the vibration peak position of the foreign matter material. Based on the position of the infrared absorption fingerprint peak of common chemical bonds, the composition of the foreign matter material is analyzed and determined.

[0082] The submicron-level nondestructive testing method for foreign objects provided in this disclosure is adaptable to the aforementioned submicron-level nondestructive testing device. It can also ensure that the test sample is not damaged during the entire testing process and does not require any additional pre-test processing such as cutting or extraction of the test sample. It is also applicable to online testing of test samples on production lines and rapid detection of foreign objects on the surface of large-size devices.

[0083] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0084] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A submicron foreign matter nondestructive inspection apparatus characterized by comprising: The application relates to a kind of middle infrared laser detection devices, including: Mobile platform (1) can move the sample piece to be measured in multiple different directions; Middle infrared laser (2) is used to emit middle infrared laser of different wavelengths to the sample piece to be measured; Laser vibrometer (3) includes beam splitter (32), beam combiner (33) and photodetector (34) arranged in its own optical path in turn; Signal processing module (4) is electrically connected with the laser vibrometer (3), for receiving and processing the measurement signal of the laser vibrometer (3); Wherein, the beam splitter (32) can split the laser emitted by the laser vibrometer (3) into detection laser and reference laser, and the detection laser can be reflected, refracted or scattered back to the laser vibrometer (3) after irradiating on the sample piece to be measured; The beam combiner (33) is used to combine the reference laser and the reflected, refracted or scattered detection laser; The photodetector (34) is used to detect the interference frequency difference of the combined laser and convert it into an electrical signal of the vibration of the sample piece to be measured; The middle infrared laser (2) can emit middle infrared laser of repetitive frequency to the sample piece to be measured, and select multiple wavelengths with equal intervals in the wave spectrum range of middle infrared laser and output them one by one, and under each wavelength, the laser vibrometer (3) runs detection task one by one, and the signal processing module (4) can draw vibration intensity distribution image according to multiple wavelengths of middle infrared laser; According to the wave peak in the vibration intensity distribution image, the wavelength of the middle infrared laser emitted by itself is selected, and random area detection or whole surface detection is carried out on other positions of the sample piece to be measured.

2. The apparatus for non-destructive testing of sub-micron foreign objects according to claim 1, wherein, The middle infrared laser (2) can irradiate the middle infrared laser on the sample to be measured through the first optical path; The first dichroic mirror (21), the second dichroic mirror (22) and the reflecting objective lens (23) are arranged in the first optical path along the irradiation direction in turn; The middle infrared laser can penetrate the first dichroic mirror (21) and the second dichroic mirror (22) respectively; The detection laser can be reflected on the sample piece to be measured or reflected back to the laser vibrometer (3) through the second dichroic mirror (22); The reflecting objective lens (23) is used to focus the middle infrared laser and the detection laser on the surface of the sample piece to be measured.

3. The apparatus for non-destructive testing of sub-micron foreign objects according to claim 2, wherein, Further comprising a focusing lens (51) and a photosensitive coupling assembly (5) arranged corresponding to the first dichroic mirror (21); The sample piece to be measured can partially reflect the middle infrared laser back to the first dichroic mirror (21) along the first optical path, and the first dichroic mirror (21) can reflect the reflected middle infrared laser to the focusing lens (51); The focusing lens (51) is used to focus the middle infrared laser reflected by the first dichroic mirror (21) on the photosensitive coupling assembly (5).

4. The apparatus for non-destructive testing of sub-micron foreign objects according to claim 2, wherein, The laser vibrometer (3) further comprises a helium-neon laser (31) and an acousto-optic modulator (35); The helium-neon laser (31) is used to emit laser towards the beam splitter (32), and the beam splitter (32) is used to split the laser into detection laser and reference laser; The reference laser irradiates on the beam combiner (33) after passing through the acousto-optic modulator (35).

5. The apparatus for non-destructive testing of sub-micron level foreign objects as claimed in claim 1, wherein The signal processing module (4) comprises a lock-in amplifier (41) and a processor (42); The lock-in amplifier (41) is electrically connected with the photodetector (34) and is used for locking phase of signal vibration measured by the photodetector (34); The processor (42) is electrically connected with the lock-in amplifier (41) and can draw a vibration intensity image according to lock-in data of the lock-in amplifier (41).

6. The apparatus for non-destructive testing of sub-micron foreign objects according to claim 5, wherein, The processor (42) is also electrically connected with the mid-infrared laser (2) and can control the mid-infrared laser (2) to output multiple mid-infrared lasers with equal intervals.

7. The apparatus for non-destructive testing of sub-micron foreign objects according to claim 5, wherein, The processor (42) is also electrically connected with the mobile platform (1) and can control the mobile platform (1) to move along a preset trajectory path and at a preset speed.

8. A non-destructive testing method of submicron foreign matter, using the non-destructive testing apparatus of submicron foreign matter according to any one of claims 1 to 7, characterized by, The method comprises the following steps: In a first step, a sample to be measured is fixedly placed on the mobile platform (1), and the mobile platform (1) is adjusted so that the sample to be measured is accurately located at a detection focal point area; In a second step, a laser vibration measuring instrument (3) emits a detection laser to the sample to be measured, and a signal processing module (4) selects a region boundary of a region to be detected in the sample to be measured based on an optical imaging picture of the laser vibration measuring instrument (3) and generates a moving scanning filling path of the mobile platform (1); In a third step, a mid-infrared laser (2) emits a mid-infrared laser with a repetitive frequency to the sample to be measured, and multiple wavelengths with equal intervals are selected in a wave spectrum range of the mid-infrared laser and are output one by one, and under each wavelength, the laser vibration measuring instrument (3) runs a detection task one by one, and the signal processing module (4) draws a vibration intensity distribution image according to the multiple wavelengths of the mid-infrared laser; In a subsequent detection step after the third step, a wavelength of the mid-infrared laser emitted by the mid-infrared laser (2) is adjusted according to a wave peak in the vibration intensity distribution image, and other positions of the sample to be measured are randomly selected and detected.

9. The submicron-level nondestructive testing method for foreign objects according to claim 8, characterized in that, Further comprising: A preliminary step before the first step: a medium film is arranged on a surface to be measured of the sample to be measured to enhance response sensitivity to the detection laser.

10. The submicron-level nondestructive testing method for foreign objects according to claim 8, characterized in that, Further comprising: A foreign matter component analysis step: a scanning output period of the mid-infrared laser (2) is set, and a signal intensity spectrum drawn by the mid-infrared laser is recorded by the lock-in amplifier (41) to obtain a wavelength of a foreign matter material vibration peak, and a foreign matter material component is analyzed and judged according to positions of infrared absorption fingerprint peaks of common chemical bonds.

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