A method and device for detecting trace impurities on a sample surface by laser ablation mass spectrometry

Abstract

The application discloses a kind of detection method and detection device of sample surface ultra trace impurity laser ablation mass spectrum, the detection method includes: preparation standard sample;Send into sample cell;Total ablation frequency is preset N, the sum of standard sample ablation frequency is N0, N0≥100, N≥KN0, K≥2;The femtosecond laser ablation mass spectrum detection of to-be-measured sample is carried out;Mixed laser ablation is carried out, and homogenization mass spectrum detection is carried out;Obtain standard addition detection curve;The content of to-be-measured element is calculated.The application can save complex sample pretreatment process, greatly shorten the analysis time, reduce the influence of pollution introduced in pretreatment process on analysis result, and by ultra large batch laser ablation and homogenization, the accurate standard addition of to-be-measured sample in aerosol system with high dilution ratio is realized, so that the standard sample that is relatively easy to obtain can be used to realize the quantitative detection of ultra trace impurity on the surface of high-purity sample such as semiconductor.

Description

Technical Field

[0001] This invention belongs to the field of laser ablation technology, and particularly relates to a laser ablation mass spectrometry method and device for detecting ultra-trace impurities on the sample surface. Background Technology

[0002] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a direct solid sample introduction technique for in-situ, micro-area, and elemental analysis. With the increasing sophistication of laser ablation systems, LA-ICP-MS has been widely applied in geology, environmental science, archaeology, and materials science. LA-ICP-MS utilizes a laser to emit a laser beam, which is then focused onto a specific area of ​​the sample using an objective lens. The energy of the pulsed laser directly ablates the solid sample into tiny particles, forming an aerosol with a carrier gas. These particles are then ionized by an inductively coupled plasma (ICP) source before being analyzed by elemental analysis.

[0003] The standard addition method, also known as the standard increment method or linear extrapolation method, is a widely used method for testing the accuracy of instruments. It is a very effective method when it is difficult to find a standard sample that closely matches the matrix of the sample being tested.

[0004] The semiconductor industry has developed rapidly. The first generation of semiconductors, represented by silicon and germanium, laid the foundation for the microelectronics industry; the second generation of semiconductors, represented by compound semiconductors such as gallium arsenide and indium phosphide, laid the foundation for the information industry; and the third generation of semiconductors, represented by wide-bandgap compound semiconductors such as silicon carbide, gallium nitride, zinc oxide, and diamond, supports the foundation for strategic emerging industries.

[0005] Inorganic elemental impurities pose a significant threat to semiconductor quality; 50% of waste products generated during semiconductor device manufacturing are caused by cleaning reagents and contaminating elements within the materials. The semiconductor industry has increasingly stringent requirements for elemental impurity analysis. Currently, the mainstream method for determining trace impurities and nanoparticles on silicon wafer / wafer surfaces is VPD+mass spectrometry. The basic operating steps of this method are as follows:

[0006] 1) Use a vacuum pick-up pen to pick up the back of the silicon wafer;

[0007] 2) Use a dropper to drop a drop of scanning solution (generally 0.5-1.5 mL, the scanning solution is generally composed of HF + H2O2, such as HF 3% + H2O2 4% etc.) onto the front side of the silicon wafer;

[0008] 3) The droplets spontaneously and rapidly scan the entire front side of the silicon wafer along with the silicon oxide layer;

[0009] 4) Manually tilt the silicon wafer to allow the scanning fluid to sweep across the entire wafer 1-2 times again;

[0010] 5) Use a pipette to transfer the scanning solution into the vial;

[0011] 6) Insert the ICP-MS sampling tube into the vial for elemental quantitative analysis.

[0012] However, existing methods for measuring trace impurities and nanoparticles on silicon wafer / wafer surfaces, as well as laser ablation systems, have the following problems:

[0013] 1) VPD equipment is expensive;

[0014] 2) The supply chain of mainstream VPD equipment is mainly controlled overseas, posing a potential risk to the domestic semiconductor industry;

[0015] 3) The droppers, pipettes, and dispensing tubes used in the VPD method are prone to contamination;

[0016] 4) During the scanning process, it is impossible to confirm whether every location has been scanned and accurately dissolved, which can lead to measurement errors.

[0017] 5) Silicon carbide is a hydrophobic material, and the VPD method is not applicable to silicon carbide semiconductors;

[0018] 6) The VPD method can only dissolve the semiconductor surface and cannot continue dissolving into lower layers;

[0019] 7) Traditional laser ablation systems based on nanosecond pulsed lasers are prone to element fractionation due to the large pulse width and long pulse duration, which affects the accuracy of quantitative measurement.

[0020] 8) Traditional laser ablation systems based on nanosecond pulsed lasers have low frequencies and cannot complete smaller single samplings;

[0021] 9) Because the content of trace impurities on the semiconductor surface is very low, it is difficult to find a matching solid standard. Summary of the Invention

[0022] In view of this, one of the objectives of the present invention is to provide a laser ablation mass spectrometry detection device and method for ultra-trace impurities on the sample surface. By using ultra-large-scale laser ablation and homogenization, the sample to be tested is accurately spiked at a high dilution ratio in an aerosol system, thereby enabling the quantitative detection of ultra-trace impurities on the surface of high-purity samples such as semiconductors using readily available standard samples.

[0023] To achieve the above objectives, the first aspect of the present invention provides a laser ablation mass spectrometry method for detecting trace impurities on a sample surface, comprising the following steps:

[0024] S1: Prepare a first standard sample and a second standard sample. The content of at least one element to be tested in the first standard sample and the second standard sample is at least K times the content of the element to be tested in the sample to be tested. The first standard sample and the second standard sample respectively include elements to be tested with different contents, and K≥2.

[0025] S2: Send at least one sample to be tested, the first standard sample, and the second standard sample into the sample cell in parallel;

[0026] S3: The total number of erosions is preset to N, and the sum of the number of erosions of the first standard sample and the second standard sample is N0, N0≥100, N≥K·N0;

[0027] S4: Mass spectrometry is used to detect the aerosol obtained by femtosecond laser ablation of the sample to be tested according to N.

[0028] S5: Perform femtosecond laser ablation on the test sample and the first and / or second standard samples according to N and N0, mix and homogenize the aerosol obtained by ablation, and then perform mass spectrometry detection.

[0029] S6: Repeat step S5 multiple times, with the number of femtosecond laser ablation operations on the first and second standard samples not being exactly the same each time, to obtain a spiking detection curve within a preset spiking range;

[0030] S7: Calculate the content of the element to be tested in the sample based on the spiked detection curve.

[0031] Preferably, after step S2, the method further includes: acquiring the galvanometer module parameters corresponding to the erosion areas of the sample to be tested, the first standard sample, and the second standard sample, respectively.

[0032] Preferably, step S1 further includes: estimating the content range of the corresponding analyte element in the sample to be tested as X. a ~X b The content of the analyte in the first standard sample is X1, and the content of the analyte in the second standard sample is X2, and X1 <X2;

[0033] The preset N and N0 in step S3 satisfy: N / N0 ≤ X1 / X b ~X2 / X a Within the range.

[0034] Preferably, the sample to be tested is a semiconductor wafer or a semiconductor chip.

[0035] Another aspect of the present invention provides a laser ablation mass spectrometry detection device for ultra-trace impurities on the sample surface. The detection device uses the above-mentioned detection method and includes a laser ablation module, a sample cell module, and a mass spectrometry detection module.

[0036] The laser ablation module includes a laser emitter, a galvanometer module, and a sample lens connected in sequence. The laser emitter is used to generate ablation laser, the galvanometer module is used to adjust the focusing position of the ablation laser at high speed, and the sample lens is an objective lens or a field lens.

[0037] The sample cell module is connected to the gas path of the mass spectrometry detection module via a homogenization tube.

[0038] Preferably, the homogenization tube includes a sample inlet, a sample outlet, an L-shaped tube, and at least two porous plates. The porous plates are disposed adjacent to the sample outlet. The L-shaped tube is used to introduce homogenizing gas. One end of the L-shaped tube faces the sample inlet, and the other end of the L-shaped tube is connected to a homogenizing gas delivery device.

[0039] Preferably, the galvanometer module is a three-dimensional galvanometer module, which includes a Z-axis moving lens, a Z-axis focusing lens, an X-axis galvanometer, and a Y-axis galvanometer.

[0040] The three-dimensional galvanometer module uses the cooperation of the Z-axis moving lens and the Z-axis focusing lens to adjust the position of the focal point of the ablation laser along the optical axis at high speed; the X-axis galvanometer and the Y-axis galvanometer are used to adjust the position of the focal point of the ablation laser along the direction perpendicular to the optical axis at high speed.

[0041] Preferably, the laser ablation module further includes an optical observation module, which is used to generate sample photographs and to determine the ablation area of ​​the sample.

[0042] The beneficial effects of this invention are:

[0043] (1) The present invention can eliminate the complicated sample pretreatment process, greatly shorten the analysis time, and reduce the impact of contamination introduced during the pretreatment process on the analysis results;

[0044] (2) The femtosecond laser of the present invention has a stable single-pulse ablation amount, which can produce uniform flat-bottomed pits and accurate quantification; and by using a galvanometer module, regardless of the response speed, movement speed and positioning accuracy, it can realize large-scale ablation sample introduction and quantitative analysis.

[0045] (3) This invention significantly increases the total number of ablation cycles of the sample and further mixes and homogenizes the aerosol after ablation, thereby achieving aerosol dilution and spiking of solid standard samples during the ablation process, avoiding the problem of finding standard samples containing trace amounts of the target element and matching the matrix.

[0046] (4) The detection method of the present invention only requires two standard samples to complete the standard addition method data analysis, which greatly reduces costs and improves efficiency. It is especially suitable for the precision detection of solid samples where the preparation of standard samples is very expensive. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the spiking curve of a laser ablation mass spectrometry method for detecting trace impurities on the sample surface, as disclosed in this invention.

[0049] Figure 2 This is a schematic diagram of the structure of a laser ablation mass spectrometry detection device for ultra-trace impurities on the sample surface disclosed in this invention.

[0050] Figure 3 This is a schematic diagram of the homogenization tube 40 disclosed in this invention;

[0051] Figure 4 This is a schematic diagram of the structure of the three-dimensional galvanometer module disclosed in this invention. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] This embodiment discloses a laser ablation mass spectrometry method for detecting trace impurities on a sample surface, comprising the following steps:

[0054] S1: Prepare a first standard sample and a second standard sample. The content of at least one analyte in both the first and second standard samples is at least K times the content of the analyte in the sample to be tested (in this example, the content of the analyte is X). a ~X b The concentration of the analyte is 1–10 ppb. The concentrations X1 and X2 of the selected two standard samples are 1 and 10 ppm, respectively, i.e., K = X1 / X b =100), the first standard sample and the second standard sample respectively contain different contents of the analyte. By controlling the number of etches of the first standard sample and the second standard sample, a spiking detection curve with a gradient can be formed while keeping the total number of etches of the standard sample constant.

[0055] S2: At least one test sample, the first reference sample and the second reference sample are fed into the sample cell side by side, software programming is performed, and laser ablation parameters, the ablation sequence of the test sample and the reference samples, ablation frequency, etc. are set;

[0056] S3: The total number of ablation times is preset to N, the sum of the ablation times of the first reference sample and the second reference sample is N0, N0≥100, N≥100N0; preferably, N0≥1000, N≥1000N0; under the above conditions, the total number of ablation times is at least 10000, preferably even 10 6 times, therefore it is necessary to ensure that the pulse time of the ablation laser is very short and the ablation area is precise, so that the generated aerosol can be uniformly mixed in the subsequent steps; in this embodiment, a femtosecond laser is used to meet the above requirements, ensuring that one round of detection of the test sample and the reference samples is completed within one sample purging cycle; on the other hand, since the focus, i.e., the position of the ablation area, needs to be adjusted quickly during the ablation process, the detection apparatus of this embodiment adopts a galvanometer module as the optical path adjusting device;

[0057] S4: Perform femtosecond laser ablation on the test sample according to N, and then perform mass spectrometry detection on the obtained aerosol;

[0058] S5: Perform femtosecond laser ablation on the test sample and the first reference sample and / or the second reference sample according to N and N0, homogenize the aerosol obtained from each ablation through a homogenizer, and then perform mass spectrometry detection; since reference samples with lower content of the element to be tested are more difficult to prepare and have lower content accuracy, the method of large-batch ablation followed by mixing and homogenization can achieve an effect similar to the dilution operation in solution quantitation, so that it is only necessary to prepare or obtain a reference sample with a relatively high content of the element to be tested (for example, for an element to be tested at the ppb level in the sample, it is only necessary to prepare a reference sample with the element to be tested at the ppm level) to meet the quantitation requirements;

[0059] S6: Repeat step S5 for multiple times, the proportions of the laser ablation times of the first reference sample and the second reference sample in each time are not completely the same, so as to obtain a standard addition detection curve within a preset standard addition range;

[0060] S7: Calculate the content of the element to be tested in the test sample according to the standard addition detection curve. For the related content calculation method, those skilled in the art can refer to the detailed steps in the prior art, which will not be repeated here.

[0061] In order to make the content of the element to be tested in the test sample as consistent as possible with the order of magnitude of the standard addition content, the estimated content range of the corresponding element to be tested in the test sample is X a ~X b , the content of the corresponding element to be tested in the first reference sample is X1, the content of the corresponding element to be tested in the second reference sample is X2, and X1<X2; then N / N0 can be set at X1 / X bX a ~X2 / X a Within the scope, X1 / X in this embodiment b =100, X2 / X a =10000, therefore N / N0 is set to the range of 100 to 10000, specifically N / N0 = 1000.

[0062] Specifically, in one embodiment, the target element content of the sample to be tested is X0 (estimated range of 1-10 ppb), the target element content of standard sample A is 1 ppm, and the target element content of standard sample B is 10 ppm. Using the sampling method shown in Table 1 for etching, the following results can be obtained: Figure 1 The spiked curve shown is used to obtain the content of the target element X0 in the sample to be tested from the spiked curve;

[0063] Table 1

[0064]

[0065]

[0066] like Figure 2 As shown, the laser ablation mass spectrometry detection device for ultra-trace impurities on the sample surface disclosed in this embodiment includes a laser ablation module 10, a sample cell module 20, and a mass spectrometry detection module 30. The laser ablation module includes a laser emitter 11, a galvanometer module 13, and a sample lens 14 connected in sequence. The laser emitter generates an ablation laser 12, the galvanometer module 13 is used to adjust the focusing position of the ablation laser at high speed, and the sample lens 14 is an objective lens. Those skilled in the art can also replace the objective lens with a field lens according to actual needs to achieve laser ablation with a larger range and greater depth of field. The sample cell module 20 is connected to the mass spectrometry detection module 30 through a homogenization tube 40. The laser-absorbed sample 15 and standard particles are mixed with the carrier gas to form an aerosol. After being homogenized by the homogenization tube 40, the aerosol enters the mass spectrometry detection module 30 through the gas path for elemental content analysis.

[0067] The laser emitter 11 is a femtosecond laser, which enables high-frequency laser ablation (up to 10,000 Hz or more). In addition, through optical path optimization, the energy of each pulse is stable, which can ensure that regular flat-bottomed pits are formed and the weight of the aerosol particles in the ablated sample is stable.

[0068] The sample cell module 20 contains a three-axis precision moving stage 23, a sample holder 22, and a sample cup 21. Protective gas / carrier gas inlets are provided on both sides of the sample cell.

[0069] The mass spectrometry detection module 30 can be a mass spectrometry analysis instrument such as ICP-MS or ICP-TOF-MS.

[0070] like Figure 3As shown, the homogenization tube 40 includes a sample inlet 41, a sample outlet 42, an L-shaped tube 43, and at least two porous plates 44. The porous plates 44 are disposed adjacent to the sample outlet 42. The L-shaped tube 43 is used to introduce homogenizing gas (generally argon, but those skilled in the art can select different gases according to the main elements to be detected). One end of the L-shaped tube 43 faces the sample inlet 41, and the other end of the L-shaped tube 43 is connected to a homogenizing gas delivery device. Specifically, the homogenization tube 43 is a quartz glass cylinder, one end of which is connected to the aerosol outlet of the laser ablation module 10, and the other end is connected to the sample inlet of the mass spectrometry detection module 30. A glass conduit extends into the interior of the quartz glass cylinder, forming an L-shape. Its inlet is connected to argon, and its outlet is directly opposite the aerosol inlet of the glass tube. Two glass perforated plates are disposed inside the quartz glass cylinder near the aerosol outlet, and the glass plates are distributed with fine circular holes of uniform size. The homogenization tube 43 is used to uniformly mix the sample 15 to be tested with the nanoparticle aerosol etched from the standard sample, avoiding fluctuations in the mass spectrometry signal and ensuring a stable signal value. The homogenization tube 40 can also be used as a general homogenization tube for the laser ablation module 10, which can thoroughly mix the sample aerosol and significantly improve the mass spectrometry signal.

[0071] like Figure 2 As shown, the laser ablation module also includes a coaxially arranged optical observation module 50, which is used to generate sample photographs. Those skilled in the art can select the ablation areas of the sample to be tested and the standard sample on the sample photograph using operating software, and automatically generate the corresponding instrument parameters of the galvanometer module, thereby completing the automatic ablation scanning of the sample to be tested and the standard sample.

[0072] In a preferred embodiment, such as Figure 4 As shown, the galvanometer module is a three-dimensional galvanometer module, which includes a Z-axis moving lens 101, a Z-axis focusing lens 102, an X-axis galvanometer 103, and a Y-axis galvanometer 104. The three-dimensional galvanometer module, through the cooperation of the Z-axis moving lens 101 and the Z-axis focusing lens 102 (adjusting the distance between the Z-axis moving lens 101 and the Z-axis focusing lens 102), rapidly adjusts the position of the ablation laser's focal point along the optical axis. The X-axis galvanometer 103 and the Y-axis galvanometer 104 are used to rapidly adjust the position of the ablation laser's focal point along a direction perpendicular to the optical axis. The X-axis galvanometer 103 and the Y-axis galvanometer 104 can each perform high-frequency reciprocating rotation around their axes. Through the high-speed rotation of the galvanometer motor in the three-dimensional galvanometer module, it is possible to switch back and forth between the test sample and the standard sample at high speed in a very short time and perform multiple laser ablations (up to 1 million times, making the quantitative spiking results more accurate), as if a single sample were being ablated.

[0073] The specific operating procedure of the detection device is as follows:

[0074] 1) Turn on the power to the computer and all subsystems, and preheat each subsystem;

[0075] 2) Open the sample cell door of the sample cell module 20, place the sample to be tested and the standard sample into the sample holder and fix them, put them into the three-axis precision moving stage of the sample cell, and close the sample cell door.

[0076] 3) The sample cell module is purged with carrier gas and protective gas, mainly helium, but different gases can be selected depending on the main elements to be detected;

[0077] 4) Using the coaxial optical observation module 50, adjust the height of the three-axis precision moving stage in the sample cell module 20, focus, and take pictures of the sample to be tested and the standard sample.

[0078] 5) Import the photos and select the erosion areas of the sample to be tested and the standard sample in the photos;

[0079] 6) Perform software programming to set laser ablation parameters, ablation sequence of the sample and standard, ablation frequency, etc.

[0080] 7) The computer begins to control each subsystem to start working according to the preset parameters;

[0081] 8) The femtosecond laser generates an ablation laser, which is focused onto the ablation area of ​​the sample and the standard sample through the optical path system to perform ablation;

[0082] 9) The sample and standard particles ablated by laser are mixed with the carrier gas to form an aerosol. After being homogenized by a homogenizer, the aerosol is introduced into the ICP-MS through the gas path for elemental content analysis.

[0083] 10) After the test is completed, open the sample cell door, take out the sample, store it in the designated area, and close the door;

[0084] 11) Once all analysis tasks are complete, shut down the carrier gas and all subsystems;

[0085] 12) Use analysis software to process the data and obtain the sample content.

[0086] The detection device and method of this invention are applicable not only to first-generation semiconductors such as silicon and germanium, but also to the detection of impurities in second- and third-generation novel semiconductors. Furthermore, this invention can be applied to the detection of ultra-trace impurities in other high-purity samples. In the prior art, it is difficult or impossible to find standard samples with extremely low elemental content for the same matrix. However, with the detection method of this invention, ordinary ppm-level standard samples can be used in combination with the sample to be tested to achieve detection.

[0087] The difference between this embodiment and the prior art is that:

[0088] 1) Compared to traditional VPD equipment, fs-LA-ICP-MS has a simpler structure, is more stable and reliable, and greatly reduces costs;

[0089] 2) Due to the use of femtosecond lasers, triaxial galvanometers and optical path systems (including beam shaping), the single-pulse ablation amount is stable, which can produce uniform flat-bottomed pits and the sampling amount can be effectively controlled;

[0090] 3) By significantly increasing the total number of ablation cycles and further mixing and homogenizing the aerosol after ablation, the aerosol dilution and spiking of solid standards can be achieved during the ablation process, avoiding the problem of finding standards containing trace amounts of the analyte and with a matching matrix.

[0091] 4) Data analysis using the standard addition method can be completed with only two standard samples, reducing costs and improving efficiency. It is especially suitable for the precise detection of solid samples where standard sample preparation is very expensive.

[0092] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0093] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laser ablation mass spectrometry method for detecting trace impurities on a sample surface, characterized in that, Includes the following steps: S1: Prepare a first standard sample and a second standard sample. The content of at least one analyte in the first standard sample and the second standard sample is at least K times the content of the analyte in the sample to be tested. The first standard sample and the second standard sample each include the analyte in different contents, where K ≥ 2. Estimate the content range of the corresponding analyte in the sample to be tested as X. a ~ X b The content of the analyte in the first standard sample is X1, and the content of the analyte in the second standard sample is X2, and X1 <X2; S2: Send at least one sample to be tested, the first standard sample, and the second standard sample into the sample cell in parallel; S3: The total number of erosions is preset to N, and the sum of the number of erosions of the first and second standard samples is N0, where N0 ≥ 100 and N ≥ K ∙ N0; N and N0 satisfy: N / N0 ≤ K ∙ N ... b ~ X2 / X a Within the range; S4: Mass spectrometry is used to detect the aerosol obtained by femtosecond laser ablation of the sample to be tested according to N. S5: Based on N and N0, the test sample, the first standard sample and the second standard sample are subjected to femtosecond laser ablation, and the aerosol obtained by ablation is mixed and homogenized before mass spectrometry detection. S6: Repeat step S5 multiple times, with the number of femtosecond laser ablation operations on the first and second standard samples not being exactly the same each time, to obtain a spiking detection curve within a preset spiking range; S7: Calculate the content of the element to be tested in the sample based on the spiked detection curve.

2. The detection method according to claim 1, characterized in that, After step S2, the method further includes: obtaining the galvanometer module parameters corresponding to the erosion areas of the sample to be tested, the first standard sample, and the second standard sample, respectively.

3. The detection method according to claim 1, characterized in that, The sample to be tested is a semiconductor wafer or a semiconductor chip.

4. A laser ablation mass spectrometry detection device for trace impurities on a sample surface, characterized in that, The detection method as described in any one of claims 1 to 3 includes a laser ablation module, a sample cell module, and a mass spectrometry detection module; The laser ablation module includes a laser emitter, a galvanometer module, and a sample lens connected in sequence. The laser emitter is used to generate ablation laser, the galvanometer module is used to adjust the focusing position of the ablation laser at high speed, and the sample lens is an objective lens or a field lens. The sample cell module is connected to the gas path of the mass spectrometry detection module via a homogenization tube.

5. The detection device according to claim 4, characterized in that, The homogenization tube includes a sample inlet, a sample outlet, an L-shaped tube, and at least two porous plates. The porous plates are disposed adjacent to the sample outlet. The L-shaped tube is used to introduce homogenizing gas. One end of the L-shaped tube faces the sample inlet, and the other end of the L-shaped tube is connected to a homogenizing gas delivery device.

6. The detection device according to claim 4, characterized in that, The galvanometer module is a three-dimensional galvanometer module, which includes a Z-axis moving lens, a Z-axis focusing lens, an X-axis galvanometer, and a Y-axis galvanometer. The three-dimensional galvanometer module uses the cooperation of the Z-axis moving lens and the Z-axis focusing lens to adjust the position of the focal point of the ablation laser along the optical axis at high speed; the X-axis galvanometer and the Y-axis galvanometer are used to adjust the position of the focal point of the ablation laser along the direction perpendicular to the optical axis at high speed.

7. The detection device according to claim 4, characterized in that, The laser ablation module also includes an optical observation module, which is used to generate sample photographs and to determine the ablation area of ​​the sample.

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