WO2024250764A1 - Raman-laser ablation-mass spectrometry combined detection apparatus and method - Google Patents

Abstract

A Raman-laser ablation-mass spectrometry combined detection apparatus and method. The Raman-laser ablation-mass spectrometry combined detection apparatus comprises a Raman laser system, a laser ablation system, a combined detection cell and a mass spectrometry detection apparatus. The combined detection method comprises: moving a sample to the position corresponding to a Raman laser window; performing Raman spectrum scanning; moving the sample to the position corresponding to an ablation laser window; and performing laser ablation-mass spectrometry scanning. By means of Raman-laser ablation-mass spectrometry combined detection, more comprehensive in-situ information of a sample can be accurately acquired, and the problem whereby Raman spectrum can only detect the surface structure of a sample is solved; and the apparatus and method are also suitable for the detection of a biological sample.

Description

A Raman-laser ablation-mass spectrometry combined detection device and combined detection method Technical Field

The present invention belongs to the technical field of laser ablation, and in particular relates to a Raman-laser ablation-mass spectrometry combined detection device and a combined detection method.

Background Art

Raman spectroscopy is a fast non-destructive testing technology, mainly used for molecular structure research; laser ablation inductively coupled plasma mass spectrometry is a technology that uses laser ablation as a direct solid sampling method and mass spectrometry to perform sample elemental analysis. Both analytical methods have a wide range of applications.

Raman spectroscopy is a type of scattering spectrum. Raman spectroscopy is based on the Raman scattering effect discovered by Indian scientist C.V. Raman. It analyzes the scattering spectrum with different frequencies from the incident light to obtain information on molecular vibration and rotation, and is applied to the study of molecular structure.

When a sample is illuminated with monochromatic light whose wavelength is much smaller than the particle size of the sample, most of the light will be transmitted in the original direction, while a small part will be scattered at different angles to produce scattered light. When observed in the vertical direction, in addition to Rayleigh scattering with the same frequency as the original incident light, there are also a series of symmetrically distributed very weak Raman spectra that are displaced (frequency shift increases or decreases) from the incident light frequency. This phenomenon is called the Raman effect.

Raman spectroscopy is very sensitive to molecular bonding and sample structure, so each molecule or sample has its own unique spectral "fingerprint". These "fingerprints" can be used for chemical identification, morphology and phase, internal pressure/stress and composition research and analysis.

Raman spectroscopy technology is widely used in chemistry, materials, physics, polymers, biology, medicine, geology and other fields due to its rich information, simple sample preparation, little interference from water, and no influence from the material form of the sample. In addition, Raman spectroscopy analysis has unique advantages such as no damage to samples, rapid analysis, low maintenance cost and simple use.

Laser ablation inductively coupled plasma mass spectrometry uses a laser to emit a laser beam, uses an objective lens to focus the laser on a specific area of the sample, uses the energy of the pulsed laser to directly form tiny particles of the solid sample, forms an aerosol with the carrier gas, and then uses an inductively coupled plasma source (ICP) to plasmatize the particles and enter the mass spectrometer for element detection.

Compared with traditional solution analysis, laser ablation inductively coupled plasma mass spectrometry uses laser ablation solid direct analysis technology, which is time-saving, labor-saving and efficient. It reduces the tedious process of sample pretreatment, and avoids the introduction of strong acids and other substances in the pretreatment to cause sample contamination and destroy the original state and structure of the sample, while retaining information such as the spatial distribution and depth distribution of sample components.

With the gradual maturity of laser ablation systems, laser ablation as a direct solid sampling method, combined with mass spectrometry, has great advantages in trace, ultra-trace element and isotope analysis. It not only plays an important role in the development of micro-area technology in earth sciences, but also extends to materials science, environmental science, marine science, life science and other fields.

At present, Raman spectroscopy and laser ablation inductively coupled plasma mass spectrometry exist independently as separate analysis methods in laboratories, and there is no case in the market where the two are combined for application.

Existing elemental analysis is mainly performed through X-ray fluorescence spectroscopy, but the detection sensitivity is not high and the detected elements are limited. Another method is ICP-MS analysis, but the existing sample pretreatment requires the introduction of strong acids and other substances for digestion, which will cause sample contamination and destroy the original state and structure of the sample, and it is impossible to obtain the in-situ information of the sample.

In summary, the prior art has the following main problems:

1. Raman spectroscopy and laser ablation inductively coupled plasma mass spectrometry are both independent tests. If you want to get the molecular structure diagram and element diagram of the sample at the same time, you must test them in different laboratories. Because they are separate and independent tests, the molecular structure diagram and element diagram of the same sample cannot completely match the in-situ information and cannot present a one-to-one correspondence.

2. Pretreatment of samples requires the introduction of strong acids and other substances for digestion, which will cause sample contamination and destroy the original state and structure of the samples, and it is impossible to obtain the in-situ information of the samples;

3. Existing methods cannot accurately obtain the three-dimensional molecular structure diagram of the sample with in-situ information. In particular, Raman spectroscopy can generally only detect the surface information of the sample and cannot perform three-dimensional imaging of the sample, and the analysis efficiency is very low.

Therefore, how to simultaneously perform Raman spectroscopy analysis and laser ablation inductively coupled plasma mass spectrometry analysis and accurately obtain in-situ information with high analysis efficiency is an urgent problem to be solved.

Summary of the invention

In view of this, one of the objects of the present invention is to provide a Raman-laser ablation-mass spectrometry combined detection device, which can simultaneously perform Raman spectroscopy analysis and laser ablation inductively coupled plasma mass spectrometry analysis, and can accurately obtain in-situ information and has a very high analysis efficiency.

Another object of the present invention is to provide a combined detection method capable of realizing the above-mentioned Raman-laser ablation-mass spectrometry combined detection device.

To achieve the above-mentioned object, the present invention provides, in a first aspect, a combined detection device of Raman-laser ablation-mass spectrometry, a Raman laser system, wherein the Raman laser system is used to emit Raman detection laser and detect Raman scattered light;

A laser ablation system, the laser ablation system is used to emit ablation laser, and the laser ablation system includes a three-dimensional galvanometer system;

A combined detection cell, the combined detection cell comprising a detection cell housing, a movable stage, a sample door, an air inlet, an air outlet, a Raman laser window, an ablation laser window and a vacuum pump, the movable stage being used to hold samples and switch and position samples between positions corresponding to the Raman laser window and the ablation laser window, the movable stage comprising a grating ruler feedback control system, the detector housing being a closed housing, the movable stage being arranged in the detection cell housing, the sample door, the air inlet, the air outlet, the Raman laser window and the ablation laser window being arranged on the detection cell housing;

A mass spectrometry detection device is used to perform mass spectrometry detection on the aerosol generated by the laser ablation system.

Preferably, the Raman laser system is a laser confocal micro-Raman spectrometer, which comprises: a laser emitter, an interference filter, a power attenuation plate, a polarizer, a reflector, a Rayleigh filter, a microscope system, a confocal pinhole, a slit, a grating and a detector, wherein the polarizer comprises a light source polarizer and a detection polarizer, and the reflector comprises a light source reflector and a detection reflector;

The laser beam emitted by the laser emitter is focused on the sample surface through a first optical path, and the laser emitter, interference filter, power attenuation plate, light source polarizer, light source reflector and Rayleigh filter are arranged on the first optical path;

The Raman scattered light generated on the sample surface enters the detector through a second optical path, and the Rayleigh filter, detection polarizer, detection reflector, confocal pinhole, slit, grating and detector are arranged on the second optical path;

The first optical path and the second optical path share the microscope system, the laser beam is reflected on the Rayleigh filter along the first optical path, and the Raman scattered light passes through the Rayleigh filter along the second optical path.

Preferably, the laser ablation system further comprises a laser emitter and a field lens; the laser emitter emits ablation laser and focuses it on the sample surface;

The three-dimensional galvanometer system includes a moving lens, a focusing lens, an X-axis galvanometer and a Y-axis galvanometer;

The movable lens can move axially, and the movable lens changes the focusing position of the ablation laser on the sample surface along the Z axis by adjusting the distance between the movable lens and the focusing lens;

The X-axis galvanometer and the Y-axis galvanometer can respectively perform high-frequency reciprocating rotation around the axis, and the X-axis galvanometer and the Y-axis galvanometer are used to adjust the focusing position in the horizontal direction of the sample surface.

Preferably, the combined detection pool further comprises a frozen sample pool, the frozen sample pool is used to hold samples that need to be kept in a frozen state, and the frozen sample pool comprises a temperature control device.

Preferably, the combined detection cell further comprises a sample observation window, and the sample observation window is used for quickly observing the sample position.

Another aspect of the present invention provides a Raman-laser ablation-mass spectrometry combined detection method, comprising the following steps:

Step S1: placing the sample into the combined detection cell and replacing the gas in the combined detection cell with a carrier gas;

Step S2: moving the sample to a position corresponding to the Raman laser window by moving the stage;

Step S3: focusing the Raman detection laser on the sample surface to perform a two-dimensional Raman spectrum scan;

Step S4: moving the sample to a position corresponding to the ablation laser window by moving the stage;

Step S5: focusing the ablation laser on the sample surface and performing two-dimensional laser ablation-mass spectrometry scanning, wherein the two-dimensional laser ablation-mass spectrometry scanning includes performing several laser ablations and sending the aerosol generated by the laser ablation to a mass spectrometry detection device for detection;

Step S6: perform data processing.

Preferably, the above-mentioned combined detection device is used.

Preferably, steps S2 to S5 are executed in a loop several times to generate three-dimensional scanning data.

Preferably, the combined detection device is specifically: the combined detection pool also includes a frozen sample pool, the frozen sample pool is used to hold samples that need to be kept in a frozen state, and the frozen sample pool includes a temperature control device;

The step S1 further includes a sample freezing process, which includes maintaining the sample at a preset temperature T by a temperature control device, and maintaining the carrier gas blowing on the sample surface in step S1.

Preferably, the sample is a liquid sample, and step S1 also includes: lowering the temperature of the liquid sample to a preset temperature T1, T1<0, by the temperature control device to quickly freeze the liquid sample, and maintaining the carrier gas purge direction toward the Raman laser window and the ablation laser window during the quick freezing of the liquid sample.

Preferably, the sample is a wafer, and the combined detection method is used to detect organic contamination and elemental contamination on the surface of the sample.

The present invention has the following beneficial effects:

1) The combination of Raman-laser ablation-mass spectrometry of the present invention can simultaneously obtain a two-dimensional molecular structure diagram and a two-dimensional element imaging diagram of the sample with in-situ information, and can also simultaneously obtain a three-dimensional molecular structure diagram and a three-dimensional element imaging diagram of the sample with in-situ information, and both the two-dimensional and three-dimensional can present a corresponding relationship based on the in-situ information; when detecting the sample, the laser ablation system is used to obtain the aerosol required for mass spectrometry detection on the one hand, and also plays a role in surface ablation on the other hand, so that the Raman laser system can detect the internal structural information below the surface of the sample; and because the scanning speed of the laser ablation system is greatly accelerated, there is no need for the Raman laser system-laser ablation system to perform confocalization, which simplifies the device;

2) Biological tissue samples only need to be processed once, and three-dimensional molecular structure maps and three-dimensional element imaging maps can be obtained by laser ablation, without the need for multiple sample processing;

3) The present invention uses Raman spectroscopy to understand the molecular structure of tissue cells, and uses laser ablation inductively coupled plasma mass spectrometry to understand the distribution of elements. The comparison of the two can obtain more comprehensive information about the sample, which is of great significance for the diagnosis of diseases and can help assist in the diagnosis of the location of the disease and its future development trend; the method can also be used for clinical tissue expression, to understand the basic principles of cancer cell growth, or to clarify the importance of the presence of different trace elements in crop production and the harmfulness of their lack, and at the same time provides a reliable and intuitive method for the research of nucleic acid modification, protein modification, cell metallomics, etc. In addition, the device and method can also be used for monitoring and confirmation of food safety, pesticide residues, and chemical industry input/output materials;

4) The present invention is particularly suitable for comprehensive detection of organic pollution and elemental pollution on the wafer surface. Raman spectroscopy is more sensitive and accurate in detecting organic matter, while elemental imaging is more sensitive to elemental pollution. There is no need to pre-treat the sample before detection, so it can meet the requirements of real-time and rapid online detection of silicon wafer surface particles and the entire pollution components in the integrated circuit production process. It also consumes less surface material and will not cause secondary pollution of the silicon wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic structural diagram of a Raman-laser ablation-mass spectrometry detection device disclosed in the present invention;

FIG2 is a schematic structural diagram of a three-dimensional galvanometer system according to an embodiment of the present invention;

FIG3 is a schematic diagram of the structure of a combined detection cell according to an embodiment of the present invention;

4 and 5 are schematic flow diagrams of the combined detection method according to Embodiment 1 of the present invention;

6 and 7 are schematic flow diagrams of the combined detection method according to the second embodiment of the present invention;

in:
101 Raman detection laser emitter; 102 interference filter; 103 power attenuation plate; 104 light source polarizer; 105
Light source reflector; 106 Rayleigh filter; 107 microscope system; 108 confocal pinhole; 109 slit; 110 grating; 111 detector; 112 detection polarizer; 113 detection reflector; 201 ablation laser emitter; 202 three-dimensional galvanometer system; 2021 moving lens; 2022 focusing lens; 2023 X-axis galvanometer; 2024 Y-axis galvanometer; 203 field mirror; 300 combined detection cell; 301 sample; 302 carrier gas; 303 sample cup; 304 moving stage; 305 aerosol; 306 air inlet; 307 air outlet; 308 vacuum pump; 309 Raman laser window; 310 ablation laser window; 311 sample observation window; 312 chamber; 313 sample door; 314 sample holder; 315 gas flow meter.

DETAILED DESCRIPTION

One of the core points of the present invention is to provide a Raman-laser ablation-mass spectrometry combined detection device, which can simultaneously perform Raman spectroscopy analysis and laser ablation inductively coupled plasma mass spectrometry analysis, and can accurately obtain in-situ information and has a very high analysis efficiency.

Another core of the present invention is a combined detection method capable of realizing the above-mentioned Raman-laser ablation-mass spectrometry combined detection device.

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Embodiment 1

Please first refer to Figure 1. The Raman-laser ablation-mass spectrometry combined detection device disclosed in this embodiment includes: a Raman laser system, a laser ablation system, a mass spectrometry detection device and a combined detection cell. The Raman laser system is used to emit Raman detection laser and detect Raman scattered light, the laser ablation system is used to emit ablation laser, and the mass spectrometry detection device is used to perform mass spectrometry detection on the aerosol generated by the laser ablation system.

As shown in FIG1 , the Raman laser system of the present embodiment is a laser confocal microscopic Raman spectrometer, which includes: a Raman detection laser emitter 101, an interference filter 102, a power attenuation plate 103, a polarizer, a reflector, a Rayleigh filter 106, a microscope system 107, a confocal pinhole 108, a slit 109, a grating 110 and a detector 111, wherein the polarizer includes a light source polarizer 104 and a detection polarizer 112, and the reflector includes a light source reflector 105 and a detection reflector 113; the laser ablation system includes a three-dimensional galvanometer system, an ablation laser emitter 201 and a field lens 203; the ablation laser emitter 201 emits an ablation laser focused on the surface of the sample 301; the Raman detection laser emitter 101 emits a light source polarizer 104 and a detection polarizer 112; ... The emitted laser beam is focused on the surface of the sample 301 through a first optical path, and the Raman detection laser emitter 101, the interference filter 102, the power attenuation plate 103, the light source polarizer 104, the light source reflector 105 and the Rayleigh filter 106 are arranged on the first optical path; the Raman scattered light generated on the surface of the sample 301 enters the detector 111 through a second optical path, and the Rayleigh filter 106, the detection polarizer 112, the detection reflector 113, the confocal pinhole 108, the slit 109, the grating 110 and the detector 111 are arranged on the second optical path; the first optical path and the second optical path share a microscope system 107, the laser beam is reflected on the Rayleigh filter 106 through the first optical path, and the Raman scattered light passes through the Rayleigh filter 106 through the second optical path.

As shown in FIG2 , the three-dimensional galvanometer system 202 includes a movable lens 2021, a focusing lens 2022, an X-axis galvanometer 2023 and a Y-axis galvanometer 2024; the movable lens 2021 can move axially, and the movable lens 2021 changes the focusing position of the ablation laser on the surface of the sample 301 along the Z-axis by adjusting the distance between the movable lens 2021 and the focusing lens 2022; the X-axis galvanometer 2023 and the Y-axis galvanometer 2024 can respectively perform high-frequency reciprocating rotation around the axis, and the X-axis galvanometer 2023 and the Y-axis galvanometer 2024 are used to adjust the focusing position in the horizontal direction on the surface of the sample 301.

Since the present embodiment adopts a three-dimensional galvanometer system 202 that can switch the focusing position at high speed, the speed of laser ablation two-dimensional scanning is greatly accelerated. Therefore, the detection strategy can also be changed from Raman single-point detection-mass spectrometry single-point detection-switching detection point strategy to Raman two-dimensional scanning-switching detection window-mass spectrometry two-dimensional scanning strategy, which greatly simplifies the device and avoids the difficulty of confocalization.

As shown in Fig. 3, the combined detection cell 300 includes a detection cell housing, a movable stage 304, a sample door 313, an air inlet 306, an air outlet 307, a Raman laser window 309, an ablation laser window 310 and a vacuum pump 308. The movable stage 304 is used to hold the sample 301 and switch the sample 301 between the positions corresponding to the Raman laser window 309 and the ablation laser window 310. The movable stage 304 includes a grating ruler feedback control system. The detector housing is a sealed housing. The movable stage 304 is arranged in the detection cell housing. The sample door 313, the air inlet 306, the air outlet 307, the Raman laser window 309 and the ablation laser window 310 are provided on the detection cell housing. In a preferred embodiment, a sample observation window 311 can also be provided on the detection cell housing for quickly observing the sample position.

This embodiment also discloses a combined detection method using the above-mentioned Raman-laser ablation-mass spectrometry combined detection device. For conventional samples such as geological samples, circular sample slices or epoxy resin targets can be made; for other types of solid samples, such as small irregular solid samples, they can be fixed on the movable stage 304 through a sample holder after pre-treatment and polishing.

FIG4 shows a method for performing Raman-laser ablation-mass spectrometry detection on the sample surface to form a Raman spectrum-surface element imaging comparison diagram:

1. First, cut and polish the sample 301 into a standard circular sample slice in the sample preparation room. If the sample 301 is small, the sample 301 needs to be made into an epoxy resin target; if it is other types of samples, first cut and polish them into the required shape;

2. Load or fix the sample 301 on a special sample holder 314, put it on the moving stage 304 through the sample door 313, replace the sample door 313, and make sure it is sealed;

3. After the combined detection cell 300 is evacuated, a carrier gas is introduced, and then the vacuum is evacuated again, and then a carrier gas is introduced. After performing this process 2 to 3 times, the carrier gas flow rate is set;

4. Move the sample on the movable stage 304 to the Raman laser window through computer control;

5. With the help of the microscope system, the sample can be accurately found, and the laser focus can be safely observed to confirm whether the laser focus is focused on the particles. At the same time, the microscope system is equipped with a high-resolution color camera that can display stored images on the computer. The computer accurately controls the moving stage 304 to make the sample to be tested move in three dimensions with high precision, and select the sample micro-area that emits Raman scattered light. The Raman detection laser emitted by the laser transmitter is purified by the monochromator, and then the optical path is changed by the reflector and then accurately focused on the sample by the objective lens; the Raman scattered light emitted by the sample is then accurately imaged on the incident slit of the monochromator by the focusing lens, and after grating separation, it enters the detector for detection, and obtains the comprehensive information of the intensity of the Raman signal in a specific range, which can indicate the high-resolution image of the surface material composition, content distribution and other related information;

6. After Raman imaging, the movable stage 304 is controlled to move to the ablation laser window;

7. The laser ablation system starts working, and the relevant working parameters (laser frequency, energy density, spot size, carrier gas flow rate, and X, Y and Z coordinate parameters, etc.) are selected (or input). The laser transmitter generates ablation laser, the X-axis galvanometer and Y-axis galvanometer deflect at high speed, the laser beam enters the field mirror and is focused on the working surface, and the computer controls the "Z" axis to achieve high-speed and precise focusing, thereby realizing high-speed laser ablation of the sample surface;

8. Laser ablation of the sample directly forms tiny particles, which form aerosol 305 with the carrier gas. The particles are then plasmatized by an inductively coupled plasma source (ICP) and then enter the mass spectrometer for element detection to form a high-quality elemental plane map of the sample;

9. After the laser ablation is completed, open the sample chamber door, take out the sample holder 314, take out the sample, and close the chamber door;

10. Take out the samples, put them into the sample box, mark them, and store them in the designated location;

11. Turn off the carrier gas and system devices according to standard procedures;

12. After being processed by professional data software, a two-dimensional Raman spectrum (molecular structure diagram) and a two-dimensional element imaging diagram with in-situ information of the sample can be obtained, and the positions of the two images can be completely corresponding. By comparing the two with each other, more comprehensive information about the sample surface can be obtained.

Since laser ablation-mass spectrometry can not only obtain the element distribution on the sample surface, but also remove a layer of material on the sample surface, it is possible to further detect the components in the deeper layers of the sample. In a preferred embodiment, as shown in FIG5 , the relevant steps (i.e., steps 4 to 8) of the two-dimensional Raman spectrum and two-dimensional element imaging method are repeatedly executed to obtain a three-dimensional Raman spectrum-three-dimensional element imaging comparison map of the above sample.

Compared with the prior art, this embodiment has the following advantages:

1. Raman spectroscopy and laser ablation use the same combined detection cell 300 and mobile stage (and sample holder 314);

2. Biological tissue samples only need to be processed once, and three-dimensional molecular structure maps and three-dimensional element imaging maps can be obtained by laser ablation, without the need for multiple sample processing;

3. The existing analysis method needs to use different instruments to test and obtain the Raman spectrum two-dimensional molecular structure map and two-dimensional element imaging map respectively. The present invention can not only obtain the sample with in-situ information two-dimensional molecular structure map and two-dimensional element imaging map, but also obtain the three-dimensional molecular structure map and three-dimensional element imaging map; when detecting the sample, the laser ablation system is used to obtain the aerosol 305 required for mass spectrometry detection on the one hand, and on the other hand, it also plays a role in surface ablation, so that the Raman laser system can detect the internal structural information below the surface of the sample;

4. The molecular structure diagram of the sample and the element imaging diagram present a one-to-one correspondence in the in-situ information, which can provide more accurate and detailed sample information;

5. The method of obtaining a two-dimensional Raman spectrum (molecular structure diagram) and a two-dimensional element imaging diagram is particularly suitable for comprehensive detection of organic and elemental contamination on the wafer surface. Raman spectroscopy is more sensitive and accurate in detecting organic matter, while element imaging is more sensitive to elemental contamination. In addition, there is no need to pretreat the sample before detection, which can meet the requirements of real-time and rapid online detection of silicon wafer surface particles and the entire contamination components in the integrated circuit production process. It also consumes less surface material and will not cause secondary contamination of the silicon wafer.

Embodiment 2

For biological samples or biological tissue sections that can be tested at room temperature, they can be placed on a glass slide and fixed by a special sample holder 314 and then tested according to the combined detection method in Example 1. For biological samples and liquid samples that need to be frozen, the difference between this embodiment and Example 1 is that the combined detection pool 300 also includes a frozen sample pool for holding samples that need to be maintained in a low temperature environment, and the frozen sample pool also includes a temperature control device for maintaining the sample at a preset sample pool temperature T.

FIG6 and FIG7 respectively show methods for performing Raman-LAB-MS detection on the above samples to form a Raman spectrum-surface element imaging comparison diagram or a three-dimensional Raman spectrum-three-dimensional element imaging comparison diagram:

1. For liquid samples, the liquid samples can be placed in the liquid tank of the freezing sample pool and quickly frozen at the quick freezing temperature T1 (the quick freezing temperature T1 can be preset according to actual conditions). For other samples that need to be kept frozen during the detection process or pre-frozen liquid samples, they are placed in the freezing pool and fixed, and the temperature of the freezing sample pool is maintained at the sample pool temperature T (the sample pool temperature T can be the same as or different from the quick freezing temperature T1) by a temperature control device. Specifically, it includes steps 1.1 to 1.3;

1.1. Load the sample into the frozen sample pool, place the frozen sample pool onto the movable stage 304 through the sample door 313, replace the sample door 313, connect the relevant gas pipelines, and pay attention to sealing;

1.2. After the combined detection cell 300 is evacuated, a carrier gas is introduced, and then the vacuum is evacuated again, and then a carrier gas is introduced. After performing this process 2 to 3 times, the carrier gas flow rate is set;

1.3. Turn on the temperature control device to control the frozen sample pool to the preset temperature (sample pool temperature T or quick freezing temperature T1); during the quick freezing process, it is necessary to ensure that argon gas is blown onto the chamber of the frozen sample pool to prevent frost on the chamber surface of the frozen sample pool, which will affect subsequent analysis;

2. Move the sample on the movable stage 304 to the Raman laser window through computer control;

3. With the help of the microscope system, the sample can be accurately found, and the laser focus can be safely observed to confirm whether the laser focus is focused on the particles. At the same time, the microscope system is equipped with a high-resolution color camera that can display stored images on the computer. The computer accurately controls the moving stage 304 to make the sample to be tested move in three dimensions with high precision, and select the sample micro-area that emits Raman scattered light. The Raman detection laser emitted by the laser transmitter is purified by the monochromator, and then the optical path is changed by the reflector and then accurately focused on the sample by the objective lens; the Raman scattered light emitted by the sample is then accurately imaged on the incident slit of the monochromator by the focusing lens, and after grating separation, it enters the detector for detection, and obtains the comprehensive information of the intensity of the Raman signal in a specific range, which can indicate the high-resolution image of the surface material composition, content distribution and other related information;

4. After Raman imaging, the movable stage 304 is controlled to move to the ablation laser window;

5. The laser ablation system starts working, and the relevant working parameters (laser frequency, energy density, spot size, carrier gas flow rate, and X, Y and Z coordinate parameters, etc.) are selected (or input). The laser transmitter generates ablation laser, the X-axis galvanometer and Y-axis galvanometer deflect at high speed, the laser beam enters the field lens and is focused onto the working surface. The computer controls the "Z" axis to achieve high-speed and precise focusing, and high-speed laser ablation of the sample surface is achieved;

6. Laser ablation of the sample directly forms tiny particles, which form aerosol 305 with the carrier gas. The particles are then plasmatized by an inductively coupled plasma source (ICP) and then enter the mass spectrometer for element detection to form a high-quality elemental plane map of the sample;

7. If three-dimensional data needs to be obtained, repeat steps 2 to 6 until all data are obtained;

8. After all tests are completed, turn off the gas, open the sample door 313, take out the frozen sample pool, and take care to prevent frostbite when taking it out. Put the sample back into the refrigerator or other designated storage place. After the frozen sample pool is taken out, close and seal the sample door 313 in time, and shut down all devices of the system according to standard procedures;

9. Process data through professional data software.

In the prior art, when liquid samples are subjected to traditional liquid analysis, various acids and reagents are inevitably used in the pre-treatment process, which may cause sample contamination. However, this embodiment uses a frozen sample pool for quick freezing, which avoids external contamination and reduces interference.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims (11)

A combined detection device of Raman-laser ablation-mass spectrometry, characterized by comprising: A Raman laser system, wherein the Raman laser system is used to emit Raman detection laser and detect Raman scattered light; A laser ablation system, the laser ablation system is used to emit ablation laser, and the laser ablation system includes a three-dimensional galvanometer system; A combined detection cell, the combined detection cell comprising a detection cell housing, a movable stage, a sample door, an air inlet, an air outlet, a Raman laser window, an ablation laser window and a vacuum pump, the movable stage being used to hold samples and switch and position samples between positions corresponding to the Raman laser window and the ablation laser window, the movable stage comprising a grating scale feedback control system, the movable stage being arranged in the detection cell housing, the sample door, the air inlet, the air outlet, the Raman laser window and the ablation laser window being arranged on the detection cell housing; A mass spectrometry detection device is used to perform mass spectrometry detection on the aerosol generated by the laser ablation system. The combined detection device according to claim 1 is characterized in that the Raman laser system is a laser confocal micro-Raman spectrometer, which comprises: a laser emitter, an interference filter, a power attenuation plate, a polarizer, a reflector, a Rayleigh filter, a microscope system, a confocal pinhole, a slit, a grating and a detector, wherein the polarizer comprises a light source polarizer and a detection polarizer, and the reflector comprises a light source reflector and a detection reflector; The laser beam emitted by the laser emitter is focused on the sample surface through a first optical path, and the laser emitter, interference filter, power attenuation plate, light source polarizer, light source reflector and Rayleigh filter are arranged on the first optical path; The Raman scattered light generated on the sample surface enters the detector through a second optical path, and the Rayleigh filter, detection polarizer, detection reflector, confocal pinhole, slit, grating and detector are arranged on the second optical path; The first optical path and the second optical path share the microscope system, the laser beam is reflected on the Rayleigh filter along the first optical path, and the Raman scattered light passes through the Rayleigh filter along the second optical path. The combined detection device according to claim 1 is characterized in that the laser ablation system further comprises a laser emitter and a field lens; the laser emitter emits ablation laser and focuses it on the sample surface; The three-dimensional galvanometer system includes a moving lens, a focusing lens, an X-axis galvanometer and a Y-axis galvanometer; The movable lens can move axially, and the movable lens changes the focusing position of the ablation laser on the sample surface along the Z axis by adjusting the distance between the movable lens and the focusing lens; The X-axis galvanometer and the Y-axis galvanometer can respectively perform high-frequency reciprocating rotation around the axis, and the X-axis galvanometer and the Y-axis galvanometer are used to adjust the focusing position in the horizontal direction of the sample surface. The combined detection device according to claim 1 is characterized in that the combined detection pool also includes a frozen sample pool, the frozen sample pool is used to hold samples that need to be maintained in a frozen state, and the frozen sample pool includes a temperature control device. The combined detection device according to claim 4 is characterized in that the combined detection cell also includes a sample observation window, and the sample observation window is used to quickly observe the sample position. A Raman-laser ablation-mass spectrometry combined detection method, characterized in that it comprises the following steps: Step S1: placing a sample into the combined detection cell, and replacing the gas in the combined detection cell with a carrier gas; Step S2: moving the sample to a position corresponding to the Raman laser window by the movable stage; Step S3: focusing the Raman detection laser on the sample surface to perform a two-dimensional Raman spectrum scan; Step S4: moving the sample to a position corresponding to the ablation laser window by the movable stage; Step S5: focusing the ablation laser on the sample surface and performing two-dimensional laser ablation-mass spectrometry scanning, wherein the two-dimensional laser ablation-mass spectrometry scanning includes performing several laser ablations and sending the aerosol generated by the laser ablation to a mass spectrometry detection device for detection; Step S6: perform data processing. The combined detection method according to claim 6 is characterized in that a combined detection device according to any one of claims 1 to 5 is used. The combined detection method according to claim 7 is characterized in that steps S2 to S5 are executed in a loop several times to generate three-dimensional scanning data. The combined detection method according to claim 7, characterized in that the combined detection device is specifically the combined detection device according to claim 4; The step S1 also includes a sample freezing process, wherein the sample freezing process includes maintaining the sample at a preset temperature T by a temperature control device. The combined detection method according to claim 9 is characterized in that the sample is a liquid sample, and step S1 also includes: lowering the temperature of the liquid sample to a preset temperature T1, T1<0, by the temperature control device, so that the liquid sample is quickly frozen, and during the quick freezing of the liquid sample, the carrier gas purge direction is maintained toward the direction of the Raman laser window and the ablation laser window. The combined detection method according to claim 7 is characterized in that the sample is a wafer, and the combined detection method is used to detect organic contamination and elemental contamination on the surface of the sample.