JP2020193855A - Base material for measurement, manufacturing method thereof, emission spectrophotometer and emission spectrophotometric analysis method - Google Patents

Abstract

To provide a base material for measurement, an emission spectrophotometer and an emission spectrophotometric analysis method, capable of highly sensitively detecting emission beam intensity of a chemical element contained in a measuring object when irradiated with a laser beam, even with a little fluid volume of the measuring object.SOLUTION: In a base material 100 for measurement, a silicon layer of a base material 30, having the silicon layer formed at least on a top layer thereof, includes a porous surface including non-through holes 10 in which an aspect ratio obtained by dividing a depth by an opening width is 3.5 or more. Furthermore, the base material 100 for measurement is a base material for measurement for measuring emission beam intensity of a chemical element contained in a measuring object 40 when a laser beam is emitted to the measuring object 40 arranged so as to cover the non-through holes 10 at least partially.SELECTED DRAWING: Figure 4C

Description

The present invention relates to a base material for measurement and a method for producing the same, and an emission spectroscopic analyzer and an emission spectroscopic analysis method.

Conventionally, research results and the like regarding the generation of submerged plasma using a solid substrate have been disclosed (Non-Patent Document 1 and Non-Patent Document 2). Further, there is disclosed a chemical analysis method in which a dissolved species is precipitated as a metal thin film on a solid substrate by electrolytic precipitation, and then elemental analysis is performed by irradiating the precipitate with a laser beam (Non-Patent Document 3). .. Further, a method of introducing a device for ejecting fine droplets onto a solid substrate and irradiating the droplets with laser light is disclosed (Non-Patent Document 4). In addition, these chemical analysis methods are generally called Laser Induced Breakdown Spectroscopy (“LIBS”).

Ayumu Matsumoto et al., "Two-dimensional space-resolved emission spectroscopy of laser ablation plasma in water", Journal of Applied Physics, American Institute of Physics, 2013, Vol. 113, No. 5, p. 0533022 / 1-7 Ayumu Matsumoto et al., "Transfer of the Species Dissolved in a Liquid into Laser Ablation Plasma: An Approach Using Emission Spectroscopy", The Journal of Physical Chemistry, American Chemical Society, 2015, Vol. 119, No. 47, p. 26506-26511 Ayumu Matsumoto et al., "On-Site Quantitative Elemental Analysis of Metal Ions in Aqueous Solutions by UnderwaterLaser-Induced Breakdown Spectroscopy Combined with Electrodeposition underControlled Potential", Analytical Chemistry, American Chemical Society, 2015, Vol. 87, No. 3, p. 1655-1661 Satoshi Ikezawa et al., "Development of Optical System for Laser-Induced Breakdown Spectroscopy by Incorporating Micro Droplet Discharge Device", 2007 Proceedings of the Kyushu Branch Joint Conference of the Institute of Electrical and Related Engineers, 2007, 02-1A-05, P. .. 5

The present inventors have conducted extensive research on a chemical analysis method for performing elemental analysis by irradiating a residue obtained by evaporating droplets on a solid substrate with a laser beam. The method is excellent in that elemental analysis can be performed even if the amount of liquid used for measurement is very small. However, as the present inventors proceeded with their research, it was confirmed that it is difficult to perform accurate elemental analysis because sufficient signal strength cannot be obtained if the method is adopted based on the conventional method. Was done.

In addition, in the above-mentioned chemical analysis method in which elemental analysis is performed by irradiating laser light, the emission spectrum tends to fluctuate depending on the irradiation position of the object to be measured, which tends to cause a decrease in measurement accuracy as a quantitative analysis. Challenges also arise. Therefore, when the amount of liquid used for measurement is small, it is strongly required to realize not only the measurement itself but also a device for improving the measurement accuracy.

By solving at least a part of the above-mentioned technical problems, the present invention can detect with high sensitivity the emission line intensity of an element having a small amount of liquid to be measured when irradiated with laser light. It can greatly contribute to the provision of a base material, an emission spectroscopic analyzer, and an emission spectroscopic analysis method.

The present inventors can realize, for example, a substance to be measured by realizing a measurement method or a measurement system capable of performing elemental analysis with high sensitivity and accuracy even if the amount of the substance to be measured is very small. We thought that it would be very useful in situations where the amount of the substance is limited, and proceeded with diligent research to improve the detection sensitivity.

The present inventors do not increase the sensitivity by changing various devices typified by a laser device for measurement, laser light irradiation conditions or spectral conditions, but instead place a base material on which a measurement target is placed ( Typically, we focused on the structure on the sample table) side. As a result of repeated trial and error, the present inventors have made the surface of the base material in contact with the object to be measured into a specific porous state, so that the sensitivity is sufficiently different from that of the conventional one. Or, it was found that the measurement result with much higher sensitivity than the conventional one can be obtained. Further, the present inventors have found that even when the amount of liquid used for measurement is small, high measurement accuracy can be realized by devising the surface of the base material. The present invention was created based on the above-mentioned findings.

One measuring base material of the present invention is a non-material having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width of the base material having a silicon layer formed on at least the uppermost layer. It has a porous surface that includes through holes. Further, in this measurement base material, when a laser beam is applied to a measurement target arranged so as to cover at least a part of the above-mentioned non-through hole, the emission line intensity of the element possessed by the measurement target is obtained. It is a base material for measurement for measuring.

The measuring base material includes at least the uppermost layer of the base material having a porous surface or a silicon layer on which a surface layer including non-through holes having an aspect ratio of 3.5 or more is formed. Therefore, when the object to be measured, which is arranged so as to cover at least a part of the non-through hole described above, is irradiated with laser light, the emission line intensity of the element possessed by the object to be measured is determined to be porous. It is possible to detect with higher sensitivity than when the surface is not formed.

Further, in one emission spectroscopic analyzer of the present invention, the aspect ratio obtained by dividing the depth by the opening width of the silicon layer of the base material on which the silicon layer is formed at least on the uppermost layer is 3.5 or more. A measurement base material having a porous surface including the non-penetrating holes of the above, in which the object to be measured is arranged so as to cover at least a part of the above-mentioned non-penetrating holes, and the object to be measured is irradiated with a laser beam. It is provided with a laser beam irradiating unit for measuring the emission line intensity and a measuring unit for measuring the emission line intensity of the element to be measured when the laser beam is irradiated.

This emission spectroscopic analyzer has a porous surface including the non-through holes having an aspect ratio of 3.5 or more, and the measurement target is arranged so as to cover at least a part of the non-through holes. A base material for use and a laser for irradiating the object to be measured with a laser beam are provided. Therefore, the measuring unit of the emission spectroscopic analyzer that measures the emission line intensity of the element possessed by the object to be measured when irradiated with the laser light has the emission line intensity, and the porous surface is formed. It is possible to detect with higher sensitivity than when there is no).

In addition, one emission spectroscopic analysis method of the present invention includes the following steps (1-1) to (1-3).
(1-1) The silicon layer of the base material on which the silicon layer is formed at least on the uppermost layer is porous including non-through holes having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width. Arrangement step of arranging the object to be measured so as to cover at least a part of the non-through hole of the base material having the surface of (1-2) Laser light irradiation for irradiating the above-mentioned object to be measured with laser light. Step (1-3) A measurement step for measuring the emission line intensity of the element of the object to be measured described above.

In this emission spectroscopic analysis method, at least one of the non-penetrating holes of the measurement base material having a porous surface or a silicon layer having a surface layer including the non-through holes having an aspect ratio of 3.5 or more described above is formed. It includes an arrangement step of arranging the object to be measured so as to cover the portion, and a laser light irradiation step of irradiating the object to be measured with laser light. Therefore, in the measurement step of this emission spectroscopic analysis method for measuring the emission line intensity of the element possessed by the object to be measured, the emission line intensity is higher than that in the case where the porous surface is not formed. It is possible to detect with sensitivity.

By the way, in the present application, as shown in FIG. 2B, even if the non-through hole 10 is not formed linearly, the "depth" of the non-through hole 10 is from the outermost surface of the base material 30. Means the linear distance D of. Therefore, the "distance S" shown in FIG. 2B is not the "depth" of the present application. Further, the "opening width" W of the non-through hole 10 in the present application is an arbitrary opening width of the non-through hole confirmed in the cross section observed using a scanning electron microscope (SEM).

According to one measuring substrate of the present invention, since it has a porous surface including a specific non-through hole, a laser is applied to an object to be measured arranged so as to cover at least a part of the non-through hole. When irradiated with light, the emission line intensity of the element to be measured can be detected with higher sensitivity than in the case where the porous surface is not formed.

Further, according to one emission spectroscopic analyzer of the present invention, at least a part of the non-penetrating hole of the measuring base material for arranging the object to be measured, which has a porous surface including a specific non-through hole. A laser for irradiating the object to be measured, which is arranged so as to cover the object, is provided. Therefore, the measuring unit of the emission spectroscopic analyzer that measures the emission line intensity of the element possessed by the object to be measured when irradiated with the laser light has the emission line intensity, and the porous surface is formed. It is possible to detect with higher sensitivity than when there is no such case.

Further, according to one emission spectroscopic analysis method of the present invention, at least one of the non-penetrating holes of the measurement base material on which a silicon layer having a porous surface or a surface layer including a specific non-through hole is formed. An arrangement step is performed in which the object to be measured is arranged so as to cover the portion. Therefore, the measuring unit of the emission spectroscopic analyzer that measures the emission line intensity of the element possessed by the object to be measured when irradiated with the laser light has the emission line intensity, and the porous surface is formed. It is possible to detect with higher sensitivity than when there is no such case.

It is a schematic diagram which shows the cross section of the base material which formed the non-through hole in 1st Embodiment. It is an enlarged view of the P area of FIG. It is a schematic diagram for demonstrating the opening width and depth of a non-through hole. FIG. 5 is an SEM (scanning electron microscope) photograph of the surface of a base material showing a state in which gold (Au) is dispersed and arranged in the form of particles or islands on the surface of the base material in the first embodiment. FIG. 5 is a cross-sectional SEM (scanning electron microscope) photograph of a base material having non-through holes formed in the first embodiment. It is a schematic diagram which shows the cross section of one process in the manufacturing process of the measuring base material in 1st Embodiment. It is a schematic diagram which shows the cross section of the base material for measurement in 1st Embodiment. It is a schematic diagram which shows the cross section of the base material for measurement in 1st Embodiment. It is a block diagram explaining the structure of the light emission spectroscopic analyzer of 1st Embodiment. This is an example of the measurement result by the emission spectroscopic analysis method of the first embodiment. It is a graph which shows the relationship between the emission line intensity by the emission spectroscopic analysis method of 1st Embodiment, and the immersion time of a base material in the non-penetrating hole formation step of 1st Embodiment. This is an example of the measurement result by the emission spectroscopic analysis method of the modified example (1) of the first embodiment. This is an example of the measurement result by the emission spectroscopic analysis method of the modified example (2) of the first embodiment. It is a schematic diagram which shows the cross section of the base material for measurement in 2nd Embodiment. It is a schematic diagram which shows the cross section of the base material which formed the non-through hole in 3rd Embodiment. It is a schematic diagram which shows the cross section of the base material for measurement in 3rd Embodiment. This is an example of a graph showing the difference in measurement results depending on the presence or absence of particles at the bottom of the non-through hole in the third embodiment. It is a schematic diagram which shows the cross section of the base material for measurement in the modification of 3rd Embodiment. It is a schematic diagram which shows the cross section of the base material for measurement in 4th Embodiment.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this description, common reference numerals are given to common parts throughout the drawings unless otherwise specified. Further, in the figure, each of the elements of each embodiment is not necessarily shown while maintaining a scale ratio of each other. In addition, some reference numerals may be omitted in order to make each drawing easier to see.

<First Embodiment>
The measurement base material 100, which is an example of the measurement base material of the present embodiment, and the manufacturing method thereof will be described.

FIG. 1 is a schematic view showing a cross section of a base material 30 on which a non-through hole 10 is formed in the present embodiment. Further, FIG. 2A is an enlarged view of the P region of FIG. Further, FIG. 2B is a schematic view for explaining the opening width and depth of the non-through hole 10. Further, FIG. 3A shows an SEM (scanning electron microscope) on the surface of the base material 30 showing a state in which gold (Au) is dispersed and arranged in the form of particles or islands on the surface of the base material 30 in the present embodiment. It is a photograph. In addition, FIG. 3B is a cross-sectional SEM (scanning electron microscope) photograph of the base material 30 on which the non-through hole 10 is formed in the present embodiment. Further, FIG. 4A is a schematic view showing a cross section of one process in the manufacturing process of the measurement base material 100 in the present embodiment. Further, each of FIGS. 4B and 4C is a schematic view showing a cross section of the measurement base material 100 in the present embodiment. Further, FIG. 5 is a configuration diagram illustrating the configuration of the emission spectroscopic analyzer 900 of the present embodiment.

In the present embodiment, as shown in FIG. 1, a base material (in this embodiment, a silicon substrate) 30 having a silicon layer having a porous surface including irregular non-through holes 10 is the object to be measured. So to speak, it plays a role as a measuring table. Here, in the present embodiment, gold (Au) particles or lumps are present at or near the deepest position of a part or all of the non-through hole 10. Further, in the present embodiment, as shown in FIG. 3B, a porous surface including a non-through hole 10 having an opening width of about 10 nm to about 20 nm and a depth of about 70 nm or more is formed. In other words, a porous surface including the non-through holes 10 having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width is formed.

More specifically, as shown in FIG. 2A, a silicon oxide layer (in other words, on at least a part of the silicon layer) is placed on the surface of at least a part of the base material 30 including the surface in the non-through hole 10. Mainly, the silicon dioxide layer) 80 is formed. The thickness of the silicon oxide layer 80 of the present embodiment varies depending on the location, but the thickness of a typical silicon oxide layer 80 is about 1 nm.

Further, in the present embodiment, as shown in FIG. 4A, the object to be measured 40 is arranged by dropping the liquid object to be measured 40 as a typical example onto the base material 30 shown in FIG. .. Then, in the present embodiment, as shown in FIG. 4B or FIG. 4C, by placing a part of the object to be measured 40 by placing it on a known hot plate set at about 100 ° C. A measurement base material 100 is manufactured in a state where at least a part of the through holes 10 or most of the non-through holes 10 are not completely filled by the object to be measured 40. As shown in FIG. 4B or FIG. 4C, only the region where the object to be measured 40 as an example exists above the surface (end face) of the base material 30 and the object to be measured 40 are inside the non-through hole 10. Areas that exist can coexist. Further, the difference between FIG. 4B and FIG. 4C is due to the difference in the evaporation situation when a part of the object to be measured 40 is evaporated. The situation in which the object to be measured 40 shown in FIG. 4C is more dry is conceptually shown. By the way, the figures of the measurement base material in the second and subsequent embodiments, which will be described later, will be described by using the measurement base material shown in FIG. 4B as a representative for convenience of explanation. A measurement substrate in the state shown in 4C can be formed.

Further, in the present embodiment, the arrangement by dropping is described as an example of the arrangement of the object to be measured 40, but the arrangement of the present embodiment is not limited to such means. For example, when the object to be measured 40 is a substance that is difficult for humans to directly collect, such as contaminated water inside the reactor, a group having a non-through hole 10 carried to the inside of the reactor by a robot. It is also possible to adopt that the object to be measured 40 is arranged in the non-through hole 10 or on the surface of the base material 30 by immersing the material 30 in contaminated water and then pulling it up.

Further, as shown in FIG. 4B, in the measurement base material 100 of the present embodiment, in the region where the measurement target 40 is in contact with the base material 30, at least a part of each non-through hole 10 is covered. Since the object to be measured 40 is arranged in, the object to be measured 40 does not necessarily have to come into contact with all of the non-through holes 10. In addition, for example, when the object to be measured 40 is arranged on the base material 30 by dropping, the size of the region where the object to be measured 40 contacts the base material 30 is determined by the type of the object to be measured 40 and the environmental conditions ( Temperature or humidity) and / or the surface condition of the base material 30 can be appropriately selected. Further, in the present embodiment, a part of the object to be measured 40 is evaporated and dried using a known hot plate, but the method for evaporating and drying the object to be measured 40 according to the present embodiment is based on the hot plate. Not limited to heating. For example, it is also possible to adopt a method of evaporating and drying the object to be measured 40 by exposing the base material 30 on which the object to be measured 40 is arranged before evaporation and drying to a high temperature atmosphere.

Next, a method for producing the measurement base material 100 of the present embodiment will be described.

The measurement base material 100 of the present embodiment can be manufactured by a manufacturing method including the following steps (S1) to (S4).
(S1) A group of gold (Au), silver (Ag), and platinum (Pt) in the form of particles or islands on the surface of the silicon layer of the base material 30 having a silicon layer formed at least on the uppermost layer. Dispersion arrangement step of dispersing and arranging at least one selected from (S2) By immersing the surface of the silicon layer in a fluoride ion-containing solution, the aspect ratio obtained by dividing the depth by the opening width is 3.5. Non-through hole forming step of forming the porous surface by forming the non-through hole 10 including the above from the above-mentioned surface (S3) Oxidizing the surface of the silicon layer including the inner surface of the non-through hole 10. Oxide film forming step of forming the silicon oxide layer 80 (S4) An arrangement step of arranging the object to be measured 40 so as to cover at least a part of the non-through hole 10.

Hereinafter, an example of each of the above steps when particulate or island-shaped gold (Au) is adopted will be described in detail.

(Distributed placement process)
First, a specific example of the distributed arrangement process of the present embodiment will be described. In one example of the dispersion arrangement step, the base material 30 (in this example, a single crystal n-type silicon (100) substrate) having a silicon layer formed on at least the uppermost layer is prepared in advance at 5 ° C. Molar concentration is 0, including hydrofluoric acid having a concentration of 0.15 mol (mol) / L (liter) (or 0.15 mol (mol) / dm ³ (hereinafter, referred to as "mol / dm ³ " for convenience)). Immerse in a .5 mmol (mmol) / dm ³ tetrachlorogold (III) acid aqueous solution for about 10 seconds to about 300 seconds. As a result, particulate gold (Au) having a particle size of several nm to several tens of nm. ) Or island-shaped gold (Au) (hereinafter, also collectively referred to as “particles 20”) was confirmed to be deposited on the surface of the base material 30, and the base material 30 was immersed in the base material 30. It can also be adopted that it is held by a known fluorocarbon resin holder that covers a part of the above.

FIG. 3A (a) is an SEM (scanning electron microscope) photograph of the surface of the base material 30 showing a state in which the particles 20 are dispersed and arranged on the base material 30, which was confirmed by immersion for 10 seconds. Further, FIG. 3A (b) is an SEM (scanning electron microscope) photograph of the surface of the base material 30 showing a state in which the particles 20 are dispersed and arranged on the base material 30, which was confirmed by immersion for 300 seconds. When particulate or island-shaped silver (Ag) or platinum (Pt) is arranged on the surface of the base material 30 instead of gold (Au), silver (Ag) or platinum (Pt) in a plan view is used. The particle size of Pt) is several nm to several hundred nm.

(Non-through hole forming process)
Next, a specific example of the non-through hole forming step of the present embodiment will be described. In an example of the non-through hole forming step, the base material 30 carrying the above-mentioned gold (Au) particles (or islands) 20 is prepared in advance at 25 ° C. in a dark room, and the molar concentration is 0.08 mol / mol /. Immerse in a 6.6 mol / dm ³ hydrofluoric acid aqueous solution containing dm ³ hydrogen peroxide for about 30 seconds. As a result, as shown in FIG. 3B, non-through holes 10 which are a large number of micropores formed from the surface of the base material 30 were confirmed. It was also found that the particles 20 were present at the bottom of the non-through holes 10. From the cross-sectional SEM photograph shown in FIG. 3B, it is confirmed that an example of the hole diameter of the non-through hole 10 is 10 nm to 20 nm. In addition, it can be seen that the pore diameter of the non-through hole 10 matches well with the particle size of the gold (Au) particles (or islands) 20 dispersed and arranged on the surface of the base material 30. Therefore, the base material 30 having the surface of the porous silicon layer is formed by the non-through hole forming step of the present embodiment.

Here, it has been confirmed that the depth of the non-through hole 10 becomes deeper as the immersion time in the non-through hole forming step becomes longer. As for the depth of the non-through hole in which the effect in the present embodiment is exhibited, a porous surface including the non-through hole 10 having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width is formed. As long as it is not particularly limited. The depth of the non-through hole 10 in which the effect of the present embodiment of detecting the emission line intensity of the element possessed by the object to be measured 40, which will be described later, can be particularly exhibited is 50 nm or more and 1 μm or less. Further, the opening width of the non-through hole 10 in which the effect of the present embodiment of detecting the emission line intensity of the element possessed by the object to be measured 40 with high sensitivity can be particularly exhibited is 1 nm or more and 1 μm or less. Further, in the non-penetrating hole forming step of the present embodiment, hydrogen peroxide is adopted as the oxidizing agent, but dissolved oxygen can be adopted as a modified example of the present embodiment instead of hydrogen peroxide.

(Oxide film forming process)
Subsequently, a specific example of the oxide film forming step of the present embodiment will be described. In an example of the oxide film forming step, the base material 30 having the surface of a porous silicon layer including the non-through holes 10 is immersed in 60% by mass of nitric acid maintained at 70 ° C. for, for example, about 30 minutes. As a result, an oxide film (mainly a silicon oxide film) 80 is formed on the surface of the base material 30 including the surface in the non-through hole 10.

(Placement process)
Next, a specific example of the arrangement process of the object to be measured 40 of the present embodiment will be described. In one example of the arrangement step, the aqueous solution is arranged on the base material 30 on which the non-through holes 10 are formed by dropping a 1 mmol / dm ³ strontium chloride aqueous solution, which is an example of the object to be measured 40. By performing the arranging step of this embodiment, the measuring base material 100 is manufactured. From the viewpoint of facilitating elemental analysis by laser irradiation, which will be described later, in the present embodiment, after the placement step is performed, for example, by placing the element on a known hot plate set at 100 ° C. Evaporation to dryness is a preferred embodiment. The outer circumference of the base material 30 is held by a resin protective tool, and the opening of the protective tool is used to spread the aqueous solution of the object to be measured 40 by dropping (the area occupied by the object to be measured 40 in a plan view). Controlling is another preferred embodiment. Further, in the present embodiment, it is particularly noteworthy that the effect of the present embodiment described later can be exhibited even if the amount of the object to be measured 40 to be dropped is as small as 5 μL (microliter) or less. Deserves. In addition, in the present embodiment, since the hydrophilic silicon oxide layer 80 is formed on the surface of the base material 30, when the object to be measured 40 is an aqueous solution, it is on the base material 30 (more accurately). In addition, the area occupied by the object to be measured 40 on the silicon oxide layer 80) can be easily expanded. As a result, as compared with the case where the silicon oxide layer 80 is absent, it is possible to facilitate the implementation of the emission spectroscopic analysis method described later and realize more accurate elemental analysis.

Next, the luminescence spectroscopic analyzer 900 and the luminescence spectroscopic analysis method of the present embodiment will be described.

In the present embodiment, the emission spectroscopic analyzer 900 is used to measure the emission line intensity of the element possessed by the object to be measured 40 when the object to be measured 40 is irradiated with laser light.

As shown in FIG. 5, the emission spectroscopic analyzer 900 of the present embodiment includes a laser light irradiation unit (manufactured by Continuum, model: MiniliteII) 90, a mirror 91, an XYZ stage 92, and a CMOS camera 93 (manufactured by Continuum, model: MiniliteII). Edmond Optics, model: EO-3212C), dichroic mirror 94a, imaging lens 94b, objective lens 94c, optical fiber bundle) 96, achromatic lens 97, and commercially available ICCD camera as a detector 98b. A spectroscope 98a equipped with (manufactured by Princeton Instruments, model: PI-MAX: 1K), a control unit 99, and a measurement base material 100 are provided. In the present embodiment, the spectroscope 98a and the detector 98b that measure the emission line intensity of the element to be measured when the laser beam is irradiated play a role as a measuring unit.

Here, in the present embodiment, the control unit 99 displays the laser light irradiation unit 90, the CMOS camera 93, the dichroic mirror 94a, the imaging lens 94b, the objective lens 94c, the detector 98b, and the XYZ stage 92. Control. Further, since the CMOS camera 93 is used for observing the surface of the measurement base material 100, for example, while observing the position of the laser beam emitted from the laser beam irradiation unit 90 using the CMOS camera 93, the CMOS camera 93 is used. It is possible to measure the emission line intensity of the element possessed by the object to be measured 40. Further, the imaging lens 94b is used to form an image observed by using the objective lens 94c on the CMOS camera 93. Further, in the present embodiment, the objective lens 94c contributes to the irradiation of the laser beam and also plays a role of observing the surface of the object to be measured included in the measurement base material 100. In the present embodiment, the dichroic mirror 94a is set to reflect the wavelength in the infrared region of the laser light and transmit the wavelength in the visible light region.

The emission spectroscopic analysis method of the present embodiment includes the following steps (T1) to (T3).
(T1) The silicon layer of the base material 30 having a silicon layer formed at least on the uppermost layer is porous including non-through holes 10 having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width. Arrangement step of arranging the object to be measured 40 so as to cover at least a part of the non-through hole 10 of the base material 30 having the surface of (T2) A laser light irradiation step of irradiating the object to be measured 40 with a laser beam. (T3) A measuring step for measuring the emission line intensity of an element possessed by the object to be measured 40.

More specifically, the arrangement step in the emission spectroscopic analysis method of the present embodiment is the same as the arrangement step in the above-mentioned manufacturing process of the measurement base material 100.

Further, in the laser light irradiation step of the present embodiment, as an example, the laser light irradiation unit 90 can irradiate the laser light set to a wavelength of 1064 nm, a pulse width of 6 ns, and an energy of 5 mJ / pulse. Using the objective lens 94c having a focal length of 40 mm, the laser beam is focused and irradiated to the object to be measured 40 on the base material 30.

Further, in the measurement step of the present embodiment, after the light emission of the element (light emission of plasma) possessed by the object to be measured 40 is focused on the inlet of the optical fiber bundle 96 through the achromatic lens 97 by using the spectroscopic mirror 94a, Light incident on the slit of the spectroscope 98a via the optical fiber bundle 96 and dispersed for each wavelength by the diffraction grating in the spectroscope 98a is imaged on the detector 98b. As a result, the emission spectrum of the element possessed by the object to be measured 40 can be measured by irradiating the laser.

Further, in the present embodiment, the light emission is incident on the slit of the spectroscope 98a equipped with the detector 98b through the optical fiber bundle 96. Further, using the XYZ stage 92 stage 92, the detection location (in other words, the laser irradiation position) of the object to be measured 40 was changed to the plane direction (XY direction) for each pulse irradiation. In addition, 1 μs after the laser irradiation, the detector 98b is operated, the gate width is 1 μs, and the emission spectrum of the emission is measured.

Next, an example of the detection result by the luminescence spectroscopic analyzer 900 and the luminescence spectroscopic analysis method of the present embodiment will be described.

FIG. 6 is an example of the measurement result by the emission spectroscopic analysis method when gold (Au) is used in the dispersion arrangement step of the present embodiment.

In FIG. 6, the result of measuring the intensity of the emission line (460.7 nm) of the strontium (Sr) atom possessed by the object to be measured 40 when the measurement base material 100 of the present embodiment is used is shown in FIG. It is indicated by "Y1 (broken line)" of. The results shown in FIG. 6 are the results when the immersion time in the dispersion arrangement step is 30 seconds and the immersion time in the non-through hole forming step is 120 seconds. Further, as a comparative example, other conditions are the measurement base material of the present embodiment except that a porous surface including non-through holes is not formed (in other words, the surface is substantially smooth). The measurement result in the same case as 100 is shown by X in FIG.

As is clear from FIG. 6, it was confirmed that the emission line intensity of the strontium (Sr) atom when the measurement base material 100 of the present embodiment was used was significantly stronger than the intensity of the comparative example. .. More specifically, it was found that the strength when the measurement base material 100 of the present embodiment was used was about 50 times or more higher than the strength of the comparative example. As a reference, as a result of investigation by the inventors of the present application, the emission line intensity when only the non-through hole forming step of the present embodiment was not performed was stronger than the value of X in FIG. It was confirmed that the strength was less than half that of Y1.

Further, FIG. 7 is a graph showing the relationship between the emission line intensity by the emission spectroscopic analysis method of the present embodiment and the immersion time of the base material 30 in the non-through hole forming step of the present embodiment.

As shown in FIG. 7, very interestingly, the emission line intensity of the strontium (Sr) atom when the measuring base material 100 of the present embodiment is used is the highest when the immersion time is between 60 seconds and 300 seconds. A tendency to become stronger was confirmed. The result is that when the non-through hole 10 having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width is formed, the emission line intensity detected from the object to be measured 40 becomes stronger. Probably showing. As a reference, as a result of investigation by the inventors of the present application, the variation in the emission line intensity depending on the laser irradiation position when only the non-through hole forming step of the present embodiment is not performed is the measurement base of the present embodiment. It was confirmed that it was suppressed by using the material 100. This is because the measurement base material 100 has a porous surface including the non-through holes 10, so that the non-through holes 10 are formed over the entire region of the surface where the object to be measured 40 is present. It is shown that the emission line intensity with less bias can be obtained as compared with the non-measurement base material.

As described above, by making the surface of the base material 30 in contact with the object to be measured 40 porous including the non-through holes 10 shown in the present embodiment, a measurement result having much higher sensitivity than before can be obtained. It turned out. Further, it has been clarified that even when the amount of the object to be measured 40 used for measurement is small, high measurement accuracy can be realized with high accuracy by providing an oxide film on the surface of the base material 30. In addition, if the measurement base material 100 of the present embodiment is adopted, it is possible to realize a non-through hole 10 using a so-called electroless process in which the base material 30 is simply immersed. Therefore, the adoption of the measurement base material 100 of the present embodiment can suppress the manufacturing cost of the measurement base material 100 relatively low and facilitate the increase in the area of the measurement base material 100.

<Modified example (1) of the first embodiment>
Since the present modification (1) is the same as the first embodiment except for the following (a1) to (a3), the description overlapping with the first embodiment may be omitted.
(A1) Platinum (Pt) was adopted instead of gold (Au) as the particles 20. (A2) Tetrachlorogold (III) having a molar concentration of 0.5 mmol (mmol) / dm ^{3 in} the dispersion arrangement step. Instead of the acid, potassium tetrachloroplatinum (II) acid having a molar concentration of 1 mmol (mmol) / dm ³ was adopted. (A3) Tetrachloroplatinum (II) acid containing hydrofluoric acid in the dispersion arrangement step. The temperature of the aqueous potassium solution was adjusted to 40 ° C.

In FIG. 8A, the result of measuring the emission line intensity of the strontium (Sr) atom possessed by the object to be measured 40 when the measurement base material 100 of the present modification (1) is used is “Y2” in FIG. 8A. (Dashed line) ”. The result shown in FIG. 8A is a result when the immersion time in the dispersion arrangement step is 90 seconds and the immersion time in the non-through hole forming step is 10 seconds. Further, as a comparative example, the same result as X in FIG. 6 is shown.

As is clear from FIG. 8A, the emission line intensity of the strontium (Sr) atom when the measurement base material 100 of the present embodiment is used becomes stronger with a sufficiently significant difference from the intensity of the comparative example. It was confirmed that. More specifically, it was found that the strength when the measurement base material 100 of the present modified example (1) was used was about 35 times or more higher than the strength of the comparative example.

As described above, by making the surface of the base material 30 in contact with the object to be measured 40 porous including the non-through holes 10 shown in the present embodiment, high-sensitivity measurement having a sufficiently significant difference as compared with the conventional case. It turns out that the results are obtained.

<Modified example (2) of the first embodiment>
Since the present modification (1) is the same as the first embodiment except for the following (b1) to (b3), the description overlapping with the first embodiment may be omitted.
(B1) With the adoption of silver (Ag) instead of gold (Au) as the particles 20, (b2) and (b1), the molar concentration was 0.5 mmol (mmol) / dm ^{3 in} the dispersion arrangement step. Molar concentration of 1 mmol (mmol) / dm ³ (silver nitrate was adopted instead of tetrachlorogold (III) acid (b3) No oxide film formation step was performed.

FIG. 8B is an example of the measurement result by the emission spectroscopic analysis method of the present modification (2). In the present modification (2), since the oxide film forming step is not performed, the area of the region occupied by the object to be measured 40 is smaller than that of the measurement base material 100 of the first embodiment. It was. Therefore, in FIG. 8B, the measured object of the first embodiment is measured by multiplying the intensity of the obtained spectrum by the ratio of the area of the modified example (2) to the measured object 40 of the first embodiment. The area of 40 is corrected so that the area of the object to be measured 40 in this modification (2) is the same.

In FIG. 8B, the result of measuring the emission line intensity of the strontium (Sr) atom possessed by the object to be measured 40 when the measurement base material 100 of the present modification (2) is used is “Y3” in FIG. 8B. (Dashed line) ”. The result shown in FIG. 8B is a result when the immersion time in the dispersion arrangement step is 15 seconds and the immersion time in the non-through hole forming step is 60 seconds. Further, as a comparative example, the same result as X in FIG. 6 is shown.

As is clear from FIG. 8B, the emission line intensity of the strontium (Sr) atom when the measurement base material 100 of the present embodiment is used becomes stronger with a sufficiently significant difference from the intensity of the comparative example. It was confirmed that. More specifically, it was found that the strength when the measurement base material 100 of the present modified example (1) was used was about 20 times or more higher than the strength of the comparative example.

As described above, by forming the surface of the base material 30 in contact with the object to be measured 40 in a porous shape including the non-through holes 10 shown in the present embodiment, the high sensitivity with a sufficiently significant difference as compared with the conventional case. It was found that the measurement results were obtained.

<Second embodiment>
The measuring base material 200, which is an example of the measuring base material of the present embodiment, and the manufacturing method thereof will be described. In the measurement base material 200 of the present embodiment, all the non-through holes 10 are completely or substantially completely filled by the measurement target 40 in the region where the measurement target 40 and the base material 30 are in contact with each other. Is the same as the measurement base material 100 of the first embodiment, except for the above. Therefore, the description overlapping with the first embodiment may be omitted.

FIG. 9 is a schematic view showing a cross section of the measurement base material 200 in the present embodiment. As shown in FIG. 9, in the measurement base material 200 of the present embodiment, the measurement target 40 is partially arranged on the surface of the base material 30 having the surface of the porous silicon layer including the non-through holes 10. Has been done. Further, in the present embodiment, in the region where the object to be measured 40 and the base material 30 are in contact with each other, all the non-through holes 10 are completely formed by the object to be measured 40 by the object to be measured 40 arranged on the base material 30. Or almost completely filled. The particles 20 are present at the bottom of the non-through holes 10.

Here, it is a preferable aspect that the same oxide film forming step as the oxide film forming step of the first embodiment is performed before the arrangement step in the first embodiment is also performed in the present embodiment. .. When an oxide film (not shown) corresponding to the silicon oxide layer 80 of the first embodiment is formed on the surface of the base material 30 of the present embodiment by the oxide film forming step, the oxide film (not shown) corresponding to the silicon oxide layer 80 of the first embodiment is formed in the non-through hole 10 with high accuracy. The object to be measured 40 can be easily entered.

Even when the measurement base material 200 of the present embodiment is adopted, the same effect as that of the measurement base material 100 of the first embodiment can be obtained.

<Third embodiment>
The measurement base material 300, which is an example of the measurement base material of the present embodiment, and the manufacturing method thereof will be described. The measurement base material 300 of the present embodiment is the same as the measurement base material 100 of the first embodiment except that the particles 20 are completely or almost absent at the bottom of the non-through hole 10. .. Therefore, the description overlapping with the first embodiment may be omitted.

FIG. 10 is a schematic view showing a cross section of the base material 30 in which 10 non-through holes are formed in the present embodiment. Further, FIG. 11 is a schematic view showing a cross section of the measurement base material 300 in the present embodiment.

As shown in FIG. 10, in the present embodiment, the particles 20 are completely or hardly present at the bottom of the non-through hole 10 of the base material 30. In the present embodiment, for example, when the element constituting the particles 20 is gold (Au) or platinum (Pt), the base material 30 is subjected to aqua regia (or hot aqua regia) immediately after the non-through hole forming step. ) By immersing the particles in (), the particles 20 can be removed by dissolving them (particle removal step). When the element constituting the particles 20 is silver (Ag), it is removed by dissolving the particles 20 by immersing the base material 30 in concentrated nitric acid immediately after the non-through hole forming step. Is possible (particle removal step).

It is preferable that the same oxide film forming step as the oxide film forming step of the first embodiment is carried out after the above-mentioned particle removing step is carried out and before the placement step of the first embodiment is carried out. It is an aspect. When an oxide film (not shown) corresponding to the silicon oxide layer 80 of the first embodiment is formed on the surface of the base material 30 of the present embodiment by the oxide film forming step, the oxide film (not shown) corresponding to the silicon oxide layer 80 of the first embodiment is formed in the non-through hole 10 with high accuracy. The object to be measured 40 can be easily entered.

Although the mechanism is not clear at this time, when the measurement base material 300 of the present embodiment is adopted, the element possessed by the measurement target 40 is more than the effect of the measurement base material 100 of the first embodiment. It was confirmed by the present inventor that the detection sensitivity with respect to the emission line intensity of

FIG. 12 is an example of a graph showing the difference in measurement results depending on the presence or absence of particles 20 at the bottom of the non-through hole 10 in the present embodiment. The result shown in FIG. 12 shows that the immersion time in the tetrachloroauric acid (III) acid aqueous solution in the dispersion arrangement step of the first embodiment is 60 seconds. In other words, it is a difference between the measurement base material 100 of the first embodiment and the measurement base material 300 of the third embodiment. The conditions are the same except for the presence or absence of the particle removing step. As shown in FIG. 12, the emission line intensity of the element (“Y4” in FIG. 12) of the element to be measured when the particle removal step is performed is the subject of the measurement base material 100 of the first embodiment. It was confirmed that the intensity of the emission line by the measurement target 40 (“Y1” in FIG. 12) was reduced to about half.

Therefore, as in the first embodiment and its modifications, and the second embodiment, the arrangement of the particles 20 at the bottom of the non-through hole 10 reduces the emission intensity of the element possessed by the object to be measured 40. , It was found to be a preferable aspect from the viewpoint of being able to detect with higher sensitivity.

<Modified example of the third embodiment>
The measurement base material 400, which is an example of the measurement base material of this modification, and the manufacturing method thereof will be described. In the measurement base material 400 of the present embodiment, in the region where the measurement target 40 and the base material 30 are in contact with each other, all of the non-through holes 10 are completely or substantially completely filled by the measurement target 40. Except for the above, it is the same as the measurement base material 300 of the third embodiment. Therefore, the description overlapping with the first embodiment or the third embodiment may be omitted.

FIG. 13 is a schematic view showing a cross section of the measurement base material 400 in this modified example. As shown in FIG. 13, in the measurement base material 400 of the present embodiment, the measurement target 40 is partially arranged on the surface of the base material 30 having the surface of the porous silicon layer including the non-through holes 10. Has been done. Further, in the present embodiment, in the region where the object to be measured 40 and the base material 30 are in contact with each other, all the non-through holes 10 are completely formed by the object to be measured 40 by the object to be measured 40 arranged on the base material 30. Or almost completely filled. There are no or almost no particles 20 at the bottom of the non-through holes 10.

Here, it is a preferable aspect that the same oxide film forming step as the oxide film forming step of the first embodiment is performed before the arrangement step in the first embodiment is also performed in the present embodiment. .. When an oxide film (not shown) corresponding to the silicon oxide layer 80 of the first embodiment is formed on the surface of the base material 30 of the present embodiment by the oxide film forming step, the oxide film (not shown) corresponding to the silicon oxide layer 80 of the first embodiment is formed in the non-through hole 10 with high accuracy. The object to be measured 40 can be easily entered.

Even when the measurement base material 400 of the present embodiment is adopted, the same effect as that of the measurement base material 100 of the first embodiment or the measurement base material 300 of the third embodiment can be obtained. ..

<Fourth Embodiment>
The measurement base material 500, which is an example of the measurement base material of the present embodiment, and the manufacturing method thereof will be described. The base material of the measurement base material 500 of the present embodiment is glass that is integrated with the silicon layer (base material 30) as a part of the base material and the silicon layer (base material 30) by a known bonding or bonding method. It has a two-layer structure composed of a substrate 50 and the like. It is the same as the measurement base material 100 of the first embodiment except that the measurement base material 500 has the two-layer structure. Therefore, the description overlapping with the first embodiment may be omitted.

FIG. 14 is a schematic view showing a cross section of the measurement base material 500 in the present embodiment. As shown in FIG. 14, in the present embodiment, as in the measurement base material 100 of the first embodiment, at least a part of the non-through hole 10 is not completely filled by the measurement target 40. The measurement base material 500 is manufactured.

Even when the measurement base material 500 of the present embodiment is adopted, the same effect as that of the measurement base material 100 of the first embodiment can be obtained.

<Other Embodiments>
By the way, in the fourth embodiment, the base material of the measurement base material 500 has a two-layer structure composed of a silicon layer (base material 30) and a glass substrate 50, but the base material of the present embodiment The material is not limited to such a configuration. For example, even when a substrate of a type different from the glass substrate that can be integrated with the silicon layer (base material 30) by a known bonding or bonding method is adopted, at least a part of the effects of the present embodiment is effective. Can be played.

Further, in each of the above-described embodiments or modifications, the non-through hole 10 having an aspect ratio of 3.5 or more obtained by dividing the depth of the non-through hole 10 by its opening width is adopted. According to the findings by the present inventor based on the relationship between the etching time and the emission line intensity shown in FIG. 7, from the viewpoint of being able to detect the emission line intensity of the element to be measured with high accuracy and high sensitivity, A suitable aspect ratio is 5 or more, more preferably 10 or more, and even more preferably 15 or more.

As described above, the modifications existing within the scope of the present invention including the other combinations of the respective embodiments or modifications are also included in the claims.

In the present invention, even if the object to be measured is a very small amount, the emission line intensity of the element to be measured can be detected with high sensitivity. Therefore, the control of the amount of impurities in the semiconductor cleaning liquid or the plating solution, the inspection of waste liquid, or the inspection of waste liquid, or It can be widely used in various industries such as component survey of contaminated water or unknown liquid inside and outside the reactor.

10 Non-through hole 20 Particle 30 Base material 40 Object to be measured 50 Glass substrate 80 Silicon oxide layer 90 Laser light irradiation part 91 Mirror 92 Stage 93 CMOS camera 94a Dycroic mirror 94b Imaging lens 94c Objective lens 96 Optical fiber bundle 97 Achromatic lens 98a Spectrometer 98b Detector 99 Control unit 100, 200, 300, 400, 500 Measurement base material 900 Emission spectroscopic analyzer

Claims (5)

The silicon layer of the base material having a silicon layer formed at least on the uppermost layer has a porous surface including non-through holes having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width.
For measuring the emission line intensity of an element possessed by the object to be measured when the object to be measured is irradiated with a laser beam so as to cover at least a part of the non-through hole.
Base material for measurement. A silicon oxide layer is provided on at least a part of the silicon layer.
The measurement base material according to claim 1. At least a part selected from the group of gold (Au), silver (Ag), and platinum (Pt) is arranged at least a part of the bottom of the non-through hole.
The measurement base material according to claim 1 or 2. The silicon layer of the base material having a silicon layer formed at least on the uppermost layer has a porous surface including non-through holes having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width. A measurement base material on which the object to be measured is arranged so as to cover at least a part of the non-through hole,
A laser beam irradiation unit for irradiating the object to be measured with a laser beam,
A measuring unit for measuring the emission line intensity of an element possessed by the object to be measured when irradiated with the laser beam is provided.
Emission spectroscopic analyzer. The silicon layer of the base material having a silicon layer formed at least on the uppermost layer has a porous surface including non-through holes having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width. An arrangement step of arranging the object to be measured so as to cover at least a part of the non-through hole of the base material, and
A laser light irradiation step of irradiating the object to be measured with a laser beam,
Including a measurement step of measuring the emission line intensity of an element possessed by the object to be measured.
Emission spectroscopic analysis method.