JP6296962B2 - Test body plate manufacturing method, test body plate manufactured thereby, and contained substance measuring apparatus using the same - Google Patents

Description

  The present invention relates to a method for preparing a test specimen plate for sensitively measuring the concentration of a contained substance in a sample by using laser-induced plasma spectroscopy, a test specimen plate produced thereby, and a contained substance measuring apparatus using the same. In particular, the present invention relates to a specimen plate manufacturing method for measuring the concentration of contained substances in a liquid sample.

  Patent Document 1 described later proposes a measuring method for measuring the surface and internal substance concentrations of a concrete structure using laser-induced plasma spectroscopy. Specifically, concrete is irradiated with carbon dioxide laser light to ablate concrete-containing materials, plasma is generated by ablation, the plasma light is decomposed for each wavelength, and imaged with a light receiving element to obtain an emission spectrum. The concentration of concrete-containing substances is measured from the emission spectrum. Since the emission spectrum here includes emission peaks based on components such as carbon, sulfur, sodium, chlorine, and iron, the excited atom can be identified from the frequency of these emission peaks. Thus, for example, the neutralization of concrete is inspected based on the strength of the carbon (C) component in the emission spectrum, or the concrete is inspected based on the strength of the sodium (Na) component or chlorine (Cl) component in the emission spectrum. It is disclosed that the influence degree of salt damage is inspected.

However, in the laser-induced plasma spectroscopy as described above, the background noise due to the shock wave is large, and the signal of the excited atom is buried in it, the sensitivity does not increase, and a concentration of 0.3 kg / m ³ or less is inspected. Since the sensitivity level is too low to be able to be performed, there is a problem that it is not practical.

  Therefore, Patent Document 2 proposes a laser-induced plasma spectroscopic analysis method that measures the concentration of a concrete-containing substance with high sensitivity. Specifically, the concrete surface is irradiated with laser light to ablate the concrete-containing material, and then the atmosphere atomized by ablation (ablation plume) with reduced white light noise and remaining excited atoms. ) Is irradiated again with laser light, and the ablated material is converted into plasma by reheating or reexcitation, and the emission from the plasmaized material is decomposed for each wavelength and imaged by a light receiving element to obtain an emission spectrum. The concentration of the concrete-containing material is measured from the emission spectrum.

FIG. 4 is a schematic configuration diagram showing an example of such a concrete-containing material measuring apparatus.
The concrete-containing material measuring apparatus 101 includes a first laser 102 for ablating a concrete-containing material by irradiating the surface of concrete S ′ as a sample to ablate the concrete-containing material, and a second laser light for the material ablated by the first laser light. A second laser 103 that converts the light emitted from the plasma into a plasma, a diffraction grating (spectral means) 104a that decomposes light emitted from the plasmaized material for each wavelength, and a controlled time difference between the light that has been split through the diffraction grating 104a The time difference between the spectroscopic analyzer 104 having a light receiving element 104b having a gate function for receiving light and acquiring an emission spectrum, and the gate opening start times of the first laser 102, the second laser 103, and the light receiving element 104b is controlled. And a timing controller 108 for inputting / outputting data to / from the computer 20. .

As the first laser 102 and the second laser 103, a YAG laser, a CO ₂ laser, an excimer laser or the like provided with a Q switch that enables time control by the timing controller 108 is used, and more specifically, a pulse width. Is an Nd: YAG laser having a pulse energy of about 10 mJ to 300 mJ.
The first laser 102 and the second laser 103 ablate the surface of the concrete S ′ with the first laser light, and then reheat or reexcite the atmosphere (ablation plume) of the material ablated with the second laser light. Are arranged to be. Specifically, the first laser beam is irradiated so as to be orthogonal to the surface of the concrete S ′, and the second laser beam is irradiated in parallel with the surface of the concrete S ′ so as to pass through the ablation plume. .

  On the other hand, light emitted from the ablation plume is guided by the optical fiber 7 and taken into the spectroscopic analyzer 104. An ICCD camera is used as the light receiving element 104b having a gate function. The ICCD camera can acquire an intensity distribution (spectrum) for each wavelength converted into spatial information by the diffraction grating 104a at a time, and can simultaneously acquire emission spectra of a large number of substances. Many substances can be measured at once.

  According to such a concrete-containing material measuring apparatus 101, the timing controller 108 sets the delay time of the Q switch of the second laser 103 with respect to the trigger signal of the first laser 102, so that the first laser light Two laser beams are generated with a predetermined time difference (delay time). For example, the laser light irradiation time difference between the first laser 102 and the second laser 103 is such that white light noise is reduced after ablation by the first laser 102 and excited atoms remain in the ablation plume. For example, it is given in the range of 500 ns to 2 μs. In addition, there is a white light noise between the time difference between the start of opening the gate of the light receiving element 104b and the irradiation of the laser beam just before that, that is, between the irradiation of the second laser light from the second laser 103 and the start of opening the gate of the light receiving element 104b. Is reduced, and a state in which excited atoms reheated or reexcited by the second laser beam remain is ensured, and is given in the range of 500 ns to 3 μs, for example.

JP 2002-296183 A JP 2009-068969 A

  By the way, in the semiconductor manufacturing process, it is important to keep the substrate surface such as a silicon wafer in a clean state in order to improve the quality and yield of the product. Therefore, there is a need for a rapid and highly sensitive elemental analysis method for specifying a substance when the substance adheres to the substrate surface from the atmosphere or the outside. In addition, not only in the semiconductor industry, but also in industries that handle metals, glass, and other solid products, high-sensitivity analysis is used to analyze the concentration of substances to be detected (for example, the concentration of metal elements) in a cleaning solution that cleans product surface dirt. There is a need for a method.

However, the laser-induced plasma spectroscopic analysis as described above is for measuring the concentration of a contained substance in a solid such as concrete S ′, and is not for measuring the concentration of a detection target substance in a liquid such as a cleaning liquid. . Since the plasma is not generated even if the laser is irradiated on the liquid surface, the liquid itself cannot be measured. Even if the liquid is evaporated and dried on the metal surface, for example, the deposit on the metal surface is irradiated with the laser. As a result, it could not be measured well because it could not be successfully fed into the gas-induced plasma.
In addition, in order to measure the concentration of the concrete-containing substance with high sensitivity, it is necessary to separate one light source or another light source (first laser 102 and second laser 103), and the configuration of the optical system and the configuration of the timing controller 108 are required. There was a problem of becoming complicated.

The present inventors have studied a laser-induced plasma spectroscopic analysis method that can measure the concentration of a substance to be detected in a liquid with high sensitivity. First, it is already known that white light noise is generated by ablation, and this has a problem that the S / N ratio deteriorates in the early stage of light emission by covering the light emission of excited atoms. Moreover, plasma is not generated in the liquid.
Therefore, after preparing a substrate on which a recess having a rough surface is formed for the purpose of allowing the liquid to conform to the surface and expanding the laser irradiation region, and forming a binder layer for attaching the sample on the recess, A test specimen plate was prepared by dropping a liquid sample onto the binder layer and evaporating it to dryness. And it discovered that white light noise (background noise) was attenuated and the light emission peak could be made remarkable by using this test body plate.

  That is, the test specimen plate manufacturing method of the present invention is a test specimen plate manufacturing method used in laser-induced plasma spectroscopy, and includes a preparation step of preparing a substrate having a recess formed on the upper surface, and a binder on the recess. A forming step of forming a layer and an arranging step of arranging a sample on the binder layer.

As described above, according to the test specimen plate manufacturing method of the present invention, plasma can be generated by evaporating and drying a liquid sample, and a metal element (detection target substance) in the liquid sample can be detected. In addition, the specimen plate generates gas plasma only by irradiation with a TEACO ₂ laser (carbon dioxide pulse laser) or the like, and the binder acts on the metal on the surface which is normally blown off by laser irradiation, so that it is sent to the gas plasma well. Can be configured easily. That is, since it is not necessary to supplement the detection target substance once with the test specimen plate, the steps until detection can be reduced.

<Means and effects for solving other problems>
In the above invention, the sample may be a liquid sample, and the liquid sample may be dropped on the binder layer and evaporated to dryness in the arranging step.
In the above invention, the substrate may be a silicon substrate or a metal substrate, and the binder layer may be a sucrose layer.
And the test body plate of this invention is produced with the test body plate preparation methods as mentioned above.

Furthermore, the contained substance measuring apparatus according to the present invention is configured to irradiate a laser beam onto the surface of the test specimen plate as described above to ablate the sample-containing substance into plasma and to emit light from the plasmaized substance with a wavelength. Each is provided with a spectroscopic analyzer that decomposes and acquires an emission spectrum.
In the above invention, when the specimen plate is manufactured, an evaporation / drying mechanism for evaporating and drying the sample or the binder may be provided.

The schematic block diagram which shows an example of the contained substance measuring device which concerns on this invention. The figure which shows an example of the test body plate which concerns on this invention. The flowchart explaining the measuring method using the apparatus of this invention. The schematic block diagram which shows an example of the conventional concrete containing material measuring apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

FIG. 1 is a schematic configuration diagram showing an example of a contained substance measuring apparatus according to the present invention. In addition, the same code | symbol is attached | subjected about the thing similar to the concrete containing material measuring apparatus 101 mentioned above.
The contained substance measuring apparatus 1 is made into a plasma, a chamber 10 in which the specimen plate S is disposed, a laser 2 that irradiates the specimen plate S with laser light, ablate the specimen-containing substance, and turns it into plasma. A spectroscopic analysis device 4 including a diffraction grating (spectral means) 4a that decomposes light emitted from a substance for each wavelength, an imaging device 4b that receives light dispersed through the diffraction grating 4a and obtains an emission spectrum, and evaporation A drying mechanism 30 and a control unit 8 that controls the laser 2 and the spectroscopic analyzer 4 and inputs and outputs data with the computer 20 are provided.

  The chamber 10 has a structure that can be sealed by a container body 12 and a lid (not shown). In addition, a window 13 for allowing laser light to pass through is formed in the container main body 12, and a cylinder (not shown) for supplying He gas (atmospheric gas) into the chamber 10 is connected. Further, a table 11 for fixing and holding the test specimen plate S is provided in the chamber 10, and this table 11 can be translated and rotated by a drive mechanism (not shown). Yes.

The laser 2 is a carbon dioxide laser device that outputs a carbon dioxide pulse laser beam having a wavelength of about 10.6 μm and a pulse width of several tens to several hundreds of ns, for example. The output of the laser 2 (pulse energy of the laser beam) varies depending on the irradiation area depending on the optical system, but is preferably 750 mJ to 1.5 J, for example. The repetition frequency of the pulsed laser beam can be selected appropriately, but is preferably about 10 Hz, for example. Further, the carbon dioxide pulse laser beam has a beam diameter that is about the same as or smaller than the size of the recess 41a of the specimen plate S. For example, the beam diameter at the irradiation point is about 2 mm to 3 mm or more, preferably 10 mm or more. And When the beam diameter is smaller than the concave portion 41a, the entire region is irradiated a plurality of times and the light emission state is integrated.
The laser 2 is disposed at a position where the laser beam is irradiated perpendicularly or obliquely to the surface of the specimen plate S.

  On the other hand, the plasma emission generated on the surface of the specimen plate S is guided by the optical fiber 7 and taken into the spectroscopic analyzer 4. The spectroscopic analyzer 4 is, for example, a multi-channel spectroscope, which decomposes the plasma emission taken in using the diffraction grating 4a into a spectrum and further measures the spectral intensity distribution using the imaging device 4b.

  The evaporation / drying mechanism 30 is a heater plate, a hot plate, or the like having a housing in which the test specimen plate S can be disposed, and the internal temperature can be adjusted to 60 ° C. to 200 ° C., for example. Yes.

  The computer 20 has a structure in which a monitor and an operation unit are connected, and the computer 20 includes a CPU. The CPU controls the entire contained substance measuring apparatus 1, measures the concentration of the contained substance from the emission spectrum acquired by the control unit 8, and displays the measurement result on the monitor.

Next, the specimen plate S used for the contained substance measuring apparatus 1 will be described. 2A and 2B are views showing an example of a test specimen plate S according to the present invention. FIG. 2A is a plan view and FIG. 2B is a cross-sectional view.
The specimen plate S includes a substrate 41 having a recess 41a formed on the upper surface, a binder layer 42 formed on the recess 41a, and a sample layer 43 formed on the binder layer 42.

The substrate 41 is a rectangular parallelepiped of, for example, 2 cm × 2 cm × 0.2 cm, and a cylindrical recess 41a having a diameter of 10 mm and a depth of 10 μm to 100 μm, for example, is formed at the center of the upper surface. Moreover, it is preferable that the surface of the recessed part 41a is roughened by sandblasting or the like.
Examples of the material of the substrate 41 include silicon and metal (copper and nickel). By using silicon or metal as the material of the substrate 41, the reaction of the shock wave generated at the time of laser light irradiation can be received by the substrate 41 to generate a shock wave at a sufficient speed, and plasma emission with intensity required for analysis can be obtained. be able to.

The binder layer 42 is formed by applying a pressure-sensitive adhesive solution (for example, 1% to 25% by weight of sucrose water) to the recess 41a by using a spray, a brush, or the like, or dropping the pressure-sensitive adhesive solution to evaporate it. Layer. By forming the binder layer 42, the detection target substance (for example, a metal element) attached to the binder layer 42 can be efficiently dissociated and excited / emitted.
Examples of the pressure-sensitive adhesive include sucrose, and the thickness of the binder layer 42 is preferably 10 μm or more and 100 μm or less.

  The sample layer 43 is a layer formed by dropping a liquid sample to be measured of, for example, 5 μl or more and 50 μl or less and evaporating it by the evaporation / drying mechanism 30 of FIG.

Here, a measurement method for measuring the concentration of a detection target substance (for example, aluminum concentration) in a liquid sample (such as a cleaning liquid after cleaning a product surface) using such a contained substance measuring apparatus 1 will be described. FIG. 3 is a flowchart for explaining the measurement method.
That is, the measurement method according to the present invention includes a preparation step (A1) for preparing the substrate 41, a formation step (A2) for forming the binder layer 42, and a placement step (A3) for arranging the sample. (A), fixing step (B1) for fixing the specimen plate S, irradiation step (B2) for irradiating the specimen plate S with the laser light, detection step (B3) for obtaining the emission spectrum, and measurement results are displayed. And a measurement method (B) including an analysis step (B4).

First, as a process of step A1 in the test specimen plate manufacturing method (A), a substrate 41 is prepared (preparation process).
Next, as the processing of step A2, 1% by weight to 25% by weight of saccharose water is dropped into the recess 41a, and is put into the evaporation / drying mechanism 30 and evaporated to form the binder layer 42 (forming process).
Next, as a process of step A3, a liquid sample such as a cleaning liquid after cleaning the product surface is dropped into the concave portion 41a, placed in the evaporation / drying mechanism 30 and evaporated to form the sample layer 43, and the test A body plate S is obtained (arrangement step).

After completion of the above-described specimen plate preparation method (A), the process proceeds to the measurement method (B).
First, as a process of step B1, the specimen plate S is fixedly held in the chamber 10, and the chamber 10 is filled with helium gas (fixing step).

Next, as a process in step B2, the sample layer 43 of the specimen plate S is irradiated with laser light to ablate the detection target substance (for example, aluminum) in the sample layer 43 and generate plasma by ablation (irradiation). Process). At this time, emission light having a wavelength (eg, 396 nm) peculiar to the detection target substance (eg, aluminum) is generated.
Next, as a process of step B3, the plasma emission generated on the surface of the test specimen plate S is guided by the optical fiber 7 and taken into the spectroscopic analyzer 4 to obtain an emission spectrum (detection step).

  Finally, as the process of step B4, the computer 20 measures the concentration of the contained substance from the acquired emission spectrum and displays the measurement result on the monitor (analysis process).

As described above, according to the contained substance measuring apparatus 1 of the present invention, plasma can be generated by evaporating and drying a liquid sample, and a metal element (detection target substance) in the liquid sample can be detected. In addition, the configuration of the specimen plate S is easy because plasma is generated only by irradiation with a TEACO ₂ laser (carbon dioxide pulse laser) or the like.

  INDUSTRIAL APPLICABILITY The present invention can be used for a measurement method or the like that measures the concentration of a contained substance in a sample with high sensitivity using laser-induced plasma spectroscopy.

S Specimen plate 41 Substrate 41a Recess 42 Binder layer 43 Sample layer

Claims (6)

A specimen plate manufacturing method used for laser-induced plasma spectroscopy,
A preparation step of preparing a substrate having a recess formed on the upper surface;
Forming a binder layer on the recess;
And a placing step of placing a sample on the binder layer. The sample is a liquid sample;
The test body plate manufacturing method according to claim 1, wherein in the arranging step, a liquid sample is dropped onto the binder layer to evaporate to dryness. The substrate is a silicon substrate or a metal substrate,
The test body plate manufacturing method according to claim 1, wherein the binder layer is a saccharose layer.   A specimen plate produced by the production method according to any one of claims 1 to 3. A laser that irradiates a sample-containing substance to a plasma by irradiating the surface of a specimen plate produced by the production method according to any one of claims 1 to 3 with laser light;
A contained substance measuring apparatus comprising: a spectroscopic analyzer that decomposes light emitted from a plasma substance for each wavelength and obtains an emission spectrum.   6. The contained substance measuring apparatus according to claim 5, further comprising an evaporation / drying mechanism for evaporating and drying the sample or the binder when the test specimen plate is produced.

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