JP7280110B2 - MEASUREMENT SUBSTRATE AND MANUFACTURING METHOD THEREOF, EMISSION SPECTRAL ANALYSIS DEVICE AND EMISSION SPECTROSCOPY ANALYSIS METHOD - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act (Publisher) University of Hyogo Public University Corporation, (Publication Name) "University of Hyogo Industry-Academia Collaborative Research Seeds Collection 2018" (Pages) "Manufacturing" Page 1, (Published Date) September 26, 2018 (Posted date) October 26, 2018, (Posted address) https://www. u-hyogo. ac. jp/research/seeds/seeds/2018/pdf/s18-1101-matsumoto. pdf (Published by) Mitsuo Sawamoto (Published by The Chemical Society of Japan), (Publication name) "The 99th Chemical Society of Japan (2019) Lecture Proceedings DVD", (Lecture number) 1 S6-06, (Publication date) March 1, 2019 (Published by) Mitsuo Sawamoto (published by The Chemical Society of Japan), (Publication name) "The 99th Chemical Society of Japan Annual Meeting (2019) Lecture Proceedings USB", (Lecture number) 1 S6-06, (Published date) March 1, 2019 (Meeting name) The 99th Chemical Society of Japan Annual Meeting (2019), (Venue) Konan University, Okamoto Campus, (Date) Heisei 31 March 16, 2019 (Posted date) March 1, 2019, (Posted address) https://nenkai. csj. jp/Proceeding/? year=2019 (Posted date) May 23, 2019, (Posted address) http://hyogosta. jp/wp-content/uploads/2019/05/fe0db8f6971bbdf6651c4b12aef2406b-1. pdf (Published by) The Surface Finishing Society of Japan, Kansai Branch Secretariat, (Publication Name) "The 20th Kansai Surface Technology Forum Abstracts", (Published page) Page 3, (Published date) November 2018 (Meeting name) 20th Kansai Surface Technology Forum, (Venue) Konan University Port Island Campus, (Date) November 21, 2018 (Publisher) Electroplating Research Group, (Publication name) "Plating Technology", (number of turns) 2019 Vol. 32, (number) No. 2, (Published page) Page 56, (Published date) March 13, 2019

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

2. Description of the Related Art Conventionally, research results and the like regarding the generation of in-liquid plasma using a solid substrate have been disclosed (Non-Patent Document 1, Non-Patent Document 2). Further, a chemical analysis method is disclosed in which elemental analysis is performed by depositing a dissolved species as a metal thin film on a solid substrate by electrolytic deposition and then irradiating the deposit with a laser beam (Non-Patent Document 3). . Further, a technique is disclosed in which a device for ejecting minute droplets onto a solid substrate is introduced and the droplets are irradiated with laser light (Non-Patent Document 4). These chemical analysis techniques are commonly referred to as Laser Induced Breakdown Spectroscopy (“LIBS”).

Ayumu Matsumoto et al., "Two-dimensionalspace-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 SpeciesDissolved in a Liquid into Laser Ablation Plasma: An Approach Using EmissionSpectroscopy", 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 an optical system for laser-induced breakdown spectroscopy by incorporating a micro-droplet ejection device", Proc. . 5

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

In addition, in the above-mentioned chemical analysis method that performs elemental analysis by irradiating laser light, the emission spectrum tends to vary depending on the irradiation position of the object to be measured, so it is easy to cause a decrease in measurement accuracy as quantitative analysis. Challenges also arise. Therefore, when the amount of liquid used for measurement is small, there is a strong demand not only for making the measurement itself possible, but also for improving the measurement accuracy.

The present invention solves at least a part of the above-described technical problems, and is capable of detecting, with high sensitivity, the emission line intensity of an element possessed by a small liquid volume of the object to be measured when irradiated with a laser beam. It can greatly contribute to the provision of a substrate for use, an emission spectroscopic analysis device, and an emission spectroscopic analysis method.

The present inventors have found that even if the amount of the substance to be measured is very small, it is possible to realize a measurement method or measurement system that can perform elemental analysis with high sensitivity and high accuracy, for example, the substance to be measured We thought that it would be very useful when there was a limited amount of , and we devoted ourselves to research to improve the detection sensitivity.

The present inventors do not increase the sensitivity by changing various devices represented by laser devices for measurement, laser light irradiation conditions or spectroscopic conditions, but a substrate for placing the measurement object ( Typically, attention was paid to the structure of the sample stage) side. As a result of repeated trial and error, the present inventors have found that by processing the surface of the base material in contact with the object to be measured into a specific porous shape, high sensitivity with a sufficiently significant difference compared with the conventional one can be obtained. , or that it is possible to obtain measurement results with significantly higher sensitivity than conventional methods. Further, the present inventors have learned that even when the amount of liquid used for measurement is small, high measurement accuracy can be achieved by devising the surface of the substrate. The present invention was created based on each of the above findings.

One substrate for measurement of the present invention is a substrate in which a silicon layer is formed at least as the uppermost layer, and the silicon layer has an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width. It has a porous surface containing through holes. In addition, when the object to be measured arranged so as to cover at least a part of the non-through hole is irradiated with a laser beam, the substrate for measurement has an emission line intensity of an element possessed by the object to be measured. It is a measurement substrate for measuring

This substrate for measurement includes, at least as the uppermost layer of the substrate, a silicon layer on which a porous surface or surface layer containing non-through pores having an aspect ratio of 3.5 or more is formed. Therefore, when an object to be measured arranged so as to cover at least a part of the non-through holes is irradiated with a laser beam, the emission line intensity of the element possessed by the object to be measured is Detection can be performed with higher sensitivity than when no surface is formed.

Further, in one optical emission spectrometer of the present invention, the silicon layer of the base material having a silicon layer formed at least as the uppermost layer has an aspect ratio obtained by dividing the depth by the opening width of 3.5 or more. a substrate for measurement having a porous surface including non-through holes of the above-mentioned non-through holes, and an object to be measured is arranged so as to cover at least a part of the non-through holes; and a measurement unit for measuring the emission line intensity of the element contained in the object to be measured when the laser beam is irradiated.

This emission spectrometer has a porous surface including a non-through hole having an aspect ratio of 3.5 or more, and a measurement target is arranged so as to cover at least a part of the non-through hole. and a laser for irradiating the object to be measured with laser light. Therefore, the measurement unit of the emission spectroscopic analyzer, which measures the emission line intensity of the element of the object to be measured when irradiated with the laser beam, measures the emission line intensity of the element having the porous surface. It is possible to detect with high sensitivity compared to the case without it).

Further, one emission spectroscopic analysis method of the present invention includes the following steps (1-1) to (1-3).
(1-1) A base material having a silicon layer formed on at least the uppermost layer, the silicon layer having 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 part of the non-through hole of the base material having a surface of (1-2) irradiating laser light to the object to be measured Step (1-3) Measurement step of measuring the emission line intensity of the element possessed by the object to be measured

This emission spectroscopic analysis method includes at least one of the non-through holes of a measurement substrate having a porous surface or a silicon layer having a surface layer, the non-through holes having an aspect ratio of 3.5 or more. and a laser beam irradiation step of irradiating the aforementioned object to be measured with a laser beam. Therefore, in the measurement step of this emission spectroscopic analysis method for measuring the emission line intensity of the element of the object to be measured, the emission line intensity is higher than when the porous surface is not formed. Sensitive detection becomes possible.

By the way, in the present application, as shown in FIG. means the linear distance D of Therefore, the "path 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 a cross section observed using a scanning electron microscope (SEM).

According to one measurement substrate of the present invention, since it has a porous surface containing specific non-through holes, a laser beam is applied to the object to be measured so as to cover at least part of the non-through holes When irradiated with light, it becomes possible to detect the emission line intensity of the element of the object to be measured with higher sensitivity than when the porous surface is not formed.

Further, according to one emission spectrometer of the present invention, a measurement substrate for arranging an object to be measured, which has a porous surface containing specific non-through holes, at least part of the non-through holes A laser for irradiating an object to be measured arranged so as to cover the is provided. Therefore, the measurement unit of the emission spectroscopic analyzer, which measures the emission line intensity of the element of the object to be measured when irradiated with the laser beam, measures the emission line intensity of the element having the porous surface. It is possible to detect with high sensitivity compared to the case without it.

Further, according to one emission spectroscopic analysis method of the present invention, at least one of the non-through holes of a measurement substrate having a silicon layer having a porous surface or surface layer containing specific non-through holes is formed. An arrangement step of arranging the object to be measured so as to cover the portion is performed. Therefore, the measurement unit of the emission spectroscopic analyzer, which measures the emission line intensity of the element of the object to be measured when irradiated with the laser beam, measures the emission line intensity of the element having the porous surface. It is possible to detect with high sensitivity compared to the case without it.

FIG. 4 is a schematic diagram showing a cross section of a base material having non-through holes formed therein in the first embodiment. FIG. 2 is an enlarged view of the P region of FIG. 1; FIG. 4 is a schematic diagram for explaining the opening width and depth of a non-through hole; 1 is a SEM (scanning electron microscope) photograph of a base material surface showing a state in which gold (Au) is dispersed in the form of particles or islands on the surface of the base material in the first embodiment. 4 is a cross-sectional SEM (scanning electron microscope) photograph of a base material having non-through holes formed thereon in the first embodiment. FIG. 3 is a schematic diagram showing a cross section of one process in the manufacturing process of the measurement base material in the first embodiment. 1 is a schematic diagram showing a cross section of a measurement base material in the first embodiment; FIG. 1 is a schematic diagram showing a cross section of a measurement base material in the first embodiment; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram explaining the structure of the emission spectroscopic analyzer of 1st Embodiment. It is an example of the measurement result by the emission spectroscopic analysis method of the first embodiment. 5 is a graph showing the relationship between the emission line intensity obtained by the emission spectroscopic analysis method of the first embodiment and the immersion time of the base material in the non-through hole forming step of the first embodiment. It is an example of the measurement result by the emission spectroscopic analysis method of the modified example (1) of the first embodiment. It is an example of the measurement result by the emission spectroscopic analysis method of the modified example (2) of the first embodiment. FIG. 4 is a schematic diagram showing a cross section of a measurement substrate in a second embodiment; FIG. 11 is a schematic diagram showing a cross section of a base material in which non-through holes are formed in the third embodiment. FIG. 10 is a schematic diagram showing a cross section of a measurement substrate in a third embodiment; FIG. 11 is an example of a graph showing the difference in measurement results depending on the presence or absence of particles at the bottom of non-through holes in the third embodiment. FIG. FIG. 11 is a schematic diagram showing a cross section of a measurement substrate in a modified example of the third embodiment; FIG. 10 is a schematic diagram showing a cross section of a measurement substrate in a fourth embodiment;

Embodiments of the present invention will be described in detail based on the accompanying drawings. In this description, common reference numerals are given to common parts throughout the drawings unless otherwise specified. Also, in the figures, each of the elements of each embodiment are not necessarily shown to scale with each other. Also, some reference numerals may be omitted to make each drawing easier to see.

<First Embodiment>
A measurement substrate 100, which is an example of the measurement substrate of the present embodiment, and a method for manufacturing the same will be described.

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

In this embodiment, as shown in FIG. 1, a substrate (in this embodiment, a silicon substrate) 30 provided with a silicon layer having a porous surface containing irregular non-through holes 10 is the object to be measured. So to speak, it plays a role as a measuring platform. Here, in the present embodiment, gold (Au) particles or lumps are present at or near the deepest positions of some or all of the non-through holes 10 . In addition, in this embodiment, as shown in FIG. 3B, a porous surface is formed that includes non-through holes 10 having an opening width of about 10 nm to about 20 nm and a depth of about 70 nm or more. In other words, a porous surface including 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 ( A silicon dioxide layer 80 is mainly formed. Although the thickness of the silicon oxide layer 80 of this embodiment varies depending on the location, the typical thickness of the 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 placed on the substrate 30 shown in FIG. 1 by dropping a liquid object to be measured 40 as a representative example. . After that, in the present embodiment, by evaporating part of the object 40 to be measured by placing it on a known hot plate set at about 100° C., as shown in FIG. 4B or 4C, A measurement substrate 100 is manufactured in which at least part of the through holes 10 or most of the non-through holes 10 are not completely filled with the object 40 to be measured. In addition, as shown in FIG. 4B or FIG. 4C, as an example, there is a region in which the object to be measured 40 exists up to the upper side of the surface (end surface) of the base material 30, and an area where the object to be measured 40 exists only inside the non-through hole 10. existing regions can be mixed. Moreover, the difference between FIG. 4B and FIG. 4C is due to the difference in the state of evaporation when part of the object 40 to be measured is evaporated. FIG. 4C conceptually shows a state in which the object 40 to be measured shown in FIG. 4C is more dry. By the way, the figure of the measurement substrate in the second and subsequent embodiments described later will be described by adopting the measurement substrate shown in FIG. 4B as a representative for convenience of explanation. A measuring substrate in the state shown in 4C can be formed

Also, in the present embodiment, placement by dropping is described as an example of placement of the object 40 to be measured, but the placement of the present embodiment is not limited to such means. For example, if the object to be measured 40 is a substance such as contaminated water inside a nuclear reactor that is difficult for a human to collect directly, the substrate having the non-through hole 10 is transported to the inside of the nuclear reactor using a robot. It is also one aspect that can be adopted 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 withdrawing the material 30 .

In addition, as shown in FIG. 4B, in the measurement base material 100 of the present embodiment, in the region where the object to be measured 40 is in contact with the base material 30, the non-through holes 10 are covered at least partially. Since the object to be measured 40 is placed in the 10, it is not necessary for the object to be measured 40 to be in contact with all of the non-through holes 10 . In addition, for example, when the object to be measured 40 is placed on the base material 30 by dropping, the size of the area where the object to be measured 40 contacts the base material 30 depends on the type of the object to be measured 40, the environmental conditions ( temperature or humidity), and/or the surface condition of the substrate 30, and the like. Further, in the present embodiment, a part of the object 40 to be measured is evaporated and dried using a known hot plate, but the method of evaporating and drying the object 40 to be measured according to the present embodiment uses a hot plate. Not limited to heating. For example, it is one aspect that can be adopted that the method of evaporating and drying the object 40 to be measured is performed by exposing the substrate 30 on which the object 40 to be measured before evaporation and drying is placed to a high-temperature atmosphere.

Next, a method for manufacturing the measurement substrate 100 of this embodiment will be described.

The measurement substrate 100 of this embodiment can be manufactured by a manufacturing method including the following steps (S1) to (S4).
(S1) Groups 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 at least the top silicon layer formed thereon. (S2) The surface of the silicon layer is immersed in a fluoride ion-containing solution so that the aspect ratio obtained by dividing the depth by the opening width is 3.5. A non-through hole forming step of forming a porous surface by forming non-through holes 10 including the above from the surface (S3) oxidizing the surface of the silicon layer including the surface inside the non-through holes 10 (S4) an arranging step of arranging the object 40 to be measured so as to cover at least a part of the non-through hole 10;

An example of each of the above steps when particulate or island gold (Au) is employed will be described in detail below.

(Distribution arrangement process)
First, a specific example of the distributed arrangement process of this embodiment will be described. In one example of the dispersing step, the base material 30 (in this example, a single crystal n-type silicon (100) substrate) having a silicon layer formed at least on the uppermost layer is preliminarily adjusted to 5° C. Containing hydrofluoric acid with a concentration of 0.15 mol (mol)/L (liter) (or 0.15 mol (mol)/dm ³ (hereinafter, expressed as “mol/dm ³ ” for convenience), with a molar concentration of 0 .5 mmol (millimol)/dm ³ of tetrachloroauric (III) acid aqueous solution for about 10 seconds to about 300 seconds.As a result, particulate gold (Au ) or island-shaped gold (Au) (hereinafter collectively referred to as “particles 20”) were deposited on the surface of the substrate 30. During the immersion, the substrate 30 It can also be held by a known fluorocarbon-based resin holder covering part of the .

FIG. 3A(a) is a SEM (Scanning Electron Microscope) photograph of the surface of substrate 30, showing the state in which particles 20 are dispersed on substrate 30, confirmed by immersion for 10 seconds. FIG. 3A(b) is an SEM (Scanning Electron Microscope) photograph of the surface of the base material 30, showing the state in which the particles 20 are dispersed on the base material 30, confirmed by immersion for 300 seconds. Note that when particulate or island-like silver (Ag) or platinum (Pt) is arranged on the surface of the base material 30 instead of gold (Au), silver (Ag) or platinum ( Pt) has a particle size of several nanometers to several hundreds of nanometers.

(Non-through hole forming step)
Next, a specific example of the non-through hole forming step of this embodiment will be described. In an example of the non-through hole forming step, the base material 30 supporting the gold (Au) particles (or islands) 20 described above was adjusted in advance to 25° C. in a dark room, and the molar concentration was 0.08 mol/ It is immersed in a 6.6 mol/dm ³ hydrofluoric acid aqueous solution containing dm ³ of hydrogen peroxide for about 30 seconds. As a result, as shown in FIG. 3B, a large number of non-through holes 10 formed from the surface of the substrate 30 were confirmed. It was also found that particles 20 were present at the bottoms of those 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 hole diameter of the non-through holes 10 well matches the particle diameter of the gold (Au) particles (or islands) 20 distributed on the surface of the substrate 30 . Therefore, the base material 30 having a surface of a 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 is longer. The depth of the non-through holes at which the effect of the present embodiment is exhibited is obtained by dividing the depth by the opening width. As long as it is not particularly limited. In addition, the depth of the non-through hole 10 that can particularly exhibit the effect of the present embodiment of highly sensitively detecting the emission line intensity of the element of the object 40 to be measured is 50 nm or more and 1 μm or less. In addition, the opening width of the non-through hole 10 that can particularly exhibit the effect of the present embodiment of detecting the emission line intensity of the element of the object 40 to be measured with high sensitivity is 1 nm or more and 1 μm or less. Also, in the non-through hole forming step of the present embodiment, hydrogen peroxide is employed as an oxidizing agent, but dissolved oxygen may be employed as a modification of the present embodiment instead of hydrogen peroxide.

(Oxide film forming step)
Next, a specific example of the oxide film forming process of this embodiment will be described. In one example of the oxide film forming process, the substrate 30 having a surface of a porous silicon layer containing non-through holes 10 is immersed in 60 mass % nitric acid maintained at 70° C. for about 30 minutes, for example. 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 inside the non-through hole 10 .

(Placement process)
Next, a specific example of the process of arranging the object to be measured 40 according to this embodiment will be described. In one example of the placement step, a 1 mmol/dm ³ aqueous solution of strontium chloride, which is an example of the object 40 to be measured, is dropped to place the aqueous solution on the substrate 30 having the non-through holes 10 formed therein. The substrate for measurement 100 is manufactured by performing the placement step of the present embodiment. In addition, 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 on a known hot plate set at 100 ° C. Evaporating to dryness is a preferred embodiment. The outer periphery of the base material 30 is held by a resin protector, and the opening of the protector is used to spread the aqueous solution of the object 40 to be measured by dripping (the area occupied by the object 40 to be measured in plan view). is another preferred aspect. In addition, in the present embodiment, even if the amount of the object to be measured 40 to be dropped is as small as, for example, 5 μL (microliter) or less, it should be noted that the effects of the present embodiment, which will be described later, can be achieved. Deserved. In addition, in this 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 can be applied to the base material 30 (more accurately In this case, the area of the region occupied by the object to be measured 40 on the silicon oxide layer 80 can be easily expanded. As a result, compared to the case where the silicon oxide layer 80 is not provided, it is possible to more easily carry out the emission spectroscopic analysis method described later and to achieve elemental analysis with higher accuracy.

Next, the emission spectroscopic analysis apparatus 900 and the emission spectroscopic analysis method of this embodiment will be described.

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

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

Here, in this embodiment, the control unit 99 controls 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. In addition, since the CMOS camera 93 is used to observe the surface of the measurement substrate 100, for example, while observing the position of the laser light emitted from the laser light irradiation unit 90 using the CMOS camera 93, It becomes possible to measure the emission line intensity of the element of the object 40 to be measured. Also, the imaging lens 94b is used to form an image on the CMOS camera 93, which is observed using the objective lens 94c. In addition, in the present embodiment, the objective lens 94c plays a role of observing the surface of the object to be measured of the measurement substrate 100 while contributing to the irradiation of the laser beam. In this embodiment, the dichroic mirror 94a is set so as to reflect the wavelength of the laser light in the infrared region and transmit the wavelength in the visible light region.

The emission spectroscopic analysis method of this embodiment includes the following steps (T1) to (T3).
(T1) A substrate 30 having a silicon layer formed on at least the uppermost layer, the silicon layer containing non-through holes 10 having an aspect ratio of 3.5 or more obtained by dividing the depth by the opening width. (T2) A laser beam irradiation step of irradiating the object 40 to be measured with a laser beam. (T3) A measurement step of measuring the emission line intensity of an element possessed by the object 40 to be measured

More specifically, the placement step in the emission spectroscopic analysis method of the present embodiment is the same as the placement step in the manufacturing process of the measurement substrate 100 described above.

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

Further, in the measurement process of the present embodiment, the luminescence (plasma luminescence) of the element of the object 40 to be measured is condensed at the entrance of the optical fiber bundle 96 through the achromatic lens 97 using the dichroic mirror 94a. The light is incident on the slit of the spectroscope 98a via the optical fiber bundle 96, and the light 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 of the object 40 to be measured can be measured by irradiating the laser.

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

Next, an example of detection results by the emission spectroscopic analysis apparatus 900 and the emission spectroscopic analysis method of this embodiment will be described.

FIG. 6 shows an example of measurement results by the emission spectroscopic analysis method when gold (Au) is used in the dispersing step of this embodiment.

In FIG. 6, the result of measuring the intensity of the emission line (460.7 nm) of the strontium (Sr) atoms of the object 40 to be measured when using the measurement substrate 100 of the present embodiment is shown in FIG. is indicated by "Y1 (broken line)". The results shown in FIG. 6 are obtained when the immersion time in the dispersing step is 30 seconds and the immersion time in the non-through hole forming step is 120 seconds. In addition, as a comparative example, the measurement substrate of the present embodiment was prepared with the exception that a porous surface containing non-through holes was not formed (in other words, the surface was substantially smooth). The measurement results for the same case as 100 are indicated by X in FIG.

As is clear from FIG. 6, it was confirmed that the emission line intensity of strontium (Sr) atoms when using the measurement substrate 100 of the present embodiment is significantly stronger than the intensity of the comparative example. . More specifically, it was found that the strength when using the measurement substrate 100 of the present embodiment was about 50 times or more the strength of the comparative example. For reference, when the inventors of the present application investigated, the emission line intensity was higher than the value of X in FIG. It was confirmed that the strength remained at less than half that of Y1.

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

As shown in FIG. 7, very interestingly, the emission line intensity of strontium (Sr) atoms when using the measurement substrate 100 of the present embodiment is the highest when the immersion time is between 60 seconds and 300 seconds. A stronger trend was observed. This result shows that when the non-through hole 10 having an aspect ratio of 3.5 or more, which is obtained by dividing the depth by the opening width, is formed, the emission line intensity detected from the object 40 to be measured is increased. It is considered to indicate For reference, when the inventors of the present invention investigated, the variation in emission line intensity depending on the irradiation position of the laser when only the non-through hole forming step of the present embodiment was not performed was the basis for measurement of the present embodiment. It was confirmed that the use of the material 100 suppressed this. This is because the measurement substrate 100 has a porous surface including the non-through holes 10, so that the non-through holes 10 are formed over the entire area of the surface where the object 40 to be measured exists. This indicates that emission line intensity with less bias can be obtained as compared with the substrate for measurement that is not treated.

As described above, by making the surface of the base material 30 in contact with the object 40 to be measured porous including the non-through holes 10 shown in this embodiment, it is possible to obtain measurement results with significantly higher sensitivity than in the past. I found out. Moreover, 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 achieved with high accuracy by providing the surface of the substrate 30 with an oxide film. In addition, by adopting the measurement substrate 100 of the present embodiment, the non-through hole 10 can be realized using a so-called electroless process in which the substrate 30 is simply immersed. Therefore, the adoption of the measurement substrate 100 of the present embodiment can keep the manufacturing cost of the measurement substrate 100 relatively low and facilitate the increase in area of the measurement substrate 100 .

<Modification (1) of the first embodiment>
Since this modified example (1) is the same as the first embodiment except for the following (a1) to (a3), description overlapping with the first embodiment can be omitted.
(a1) platinum (Pt) was adopted as the particles 20 instead of gold ( ^Au ); Potassium tetrachloroplatinate(II) with a molar concentration of 1 mmol (millimol)/dm ³ was employed instead of the acid. The temperature of the potassium aqueous solution was adjusted to 40°C

In FIG. 8A, the result of measuring the emission line intensity of the strontium (Sr) atoms of the object 40 to be measured when using the measurement substrate 100 of Modification (1) is "Y2 (broken line)”. The results shown in FIG. 8A are obtained when the immersion time in the dispersing step is 90 seconds and the immersion time in the non-through hole forming step is 10 seconds. Also, as a comparative example, the same result as X in FIG. 6 is shown.

As is clear in FIG. 8A, the emission line intensity of strontium (Sr) atoms when using the measurement substrate 100 of the present embodiment is stronger than the intensity of the comparative example with a sufficiently significant difference. was confirmed. More specifically, it was found that the strength when using the measurement substrate 100 of Modification Example (1) was about 35 times or more the strength of the comparative example.

As described above, by making the surface of the substrate 30 in contact with the object 40 to be measured porous including the non-through holes 10 shown in this embodiment, high-sensitivity measurement with a sufficiently significant difference compared to the conventional It has been found that results are obtained.

<Modification (2) of the first embodiment>
Since this modification (1) is the same as the first embodiment except for the following (b1) to (b3), description overlapping with the first embodiment can be omitted.
(b1) As the particles 20, silver ⁽ Ag) is adopted instead of gold (Au). Silver nitrate with a molar concentration of 1 mmol (millimol)/dm ³ was used instead of tetrachlorogold (III) acid. (b3) No oxide film forming step was performed.

FIG. 8B is an example of the measurement result by the emission spectroscopic analysis method of this modified example (2). In addition, since the oxide film forming step is not performed in this modified example (2), the area of the region occupied by the object to be measured 40 is smaller than in the case of the measurement substrate 100 of the first embodiment. rice field. Therefore, in FIG. 8B, 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 measured object of the first embodiment 40 and the area of the object to be measured 40 in this modified example (2) are corrected to be the same.

In FIG. 8B, the result of measuring the emission line intensity of the strontium (Sr) atoms of the object 40 to be measured when using the measurement substrate 100 of Modification (2) is "Y3 (broken line)”. The results shown in FIG. 8B are obtained when the immersion time in the dispersing process is 15 seconds and the immersion time in the non-through hole forming process is 60 seconds. Also, 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 strontium (Sr) atoms when using the measurement substrate 100 of the present embodiment is stronger than the intensity of the comparative example with a sufficiently significant difference. was confirmed. More specifically, it was found that the strength when using the measurement substrate 100 of Modification Example (1) was about 20 times or more that 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 state including the non-through holes 10 shown in the present embodiment, high sensitivity with a sufficiently significant difference compared to the conventional It was found that measurement results were obtained.

<Second embodiment>
A measurement substrate 200, which is an example of the measurement substrate of the present embodiment, and a method for manufacturing the same will be described. In the measurement substrate 200 of the present embodiment, the non-through holes 10 are completely or substantially completely filled with the object 40 to be measured in the region where the object 40 to be measured and the substrate 30 are in contact. Except for , it is the same as the measurement substrate 100 of the first embodiment. Therefore, the description overlapping with the first embodiment can be omitted.

FIG. 9 is a schematic diagram showing a cross section of the measurement substrate 200 in this embodiment. As shown in FIG. 9, the measurement substrate 200 of the present embodiment includes a substrate 30 having a surface of a porous silicon layer including non-through holes 10, and an object 40 to be measured is partially arranged on the surface of the substrate 30. It is In addition, in the present embodiment, in the region where the object 40 to be measured and the base material 30 are in contact, the object 40 to be measured placed on the base material 30 completely covers the non-through hole 10 by the object 40 to be measured. or almost completely filled. Particles 20 are present at the bottoms of these non-through holes 10 .

Here, it is a preferred aspect that an oxide film forming step similar to the oxide film forming step of the first embodiment is performed before the disposing step of the first embodiment is performed also in this embodiment. . By the oxide film forming step, 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. It is possible to make it easier for the object 40 to be measured to enter.

Even when the measurement substrate 200 of the present embodiment is adopted, the same effects as those of the measurement substrate 100 of the first embodiment can be obtained.

<Third Embodiment>
A measurement substrate 300, which is an example of the measurement substrate of the present embodiment, and a method for manufacturing the same will be described. The measurement substrate 300 of this embodiment is the same as the measurement substrate 100 of the first embodiment, except that no or almost no particles 20 are present at the bottom of the non-through holes 10. . Therefore, the description overlapping with the first embodiment can be omitted.

FIG. 10 is a schematic diagram showing a cross section of a base material 30 in which non-through holes 10 are formed in this embodiment. Moreover, FIG. 11 is a schematic diagram showing a cross section of the measurement substrate 300 in this embodiment.

As shown in FIG. 10, in this embodiment, no or almost no particles 20 are present at the bottom of the non-through holes 10 of the substrate 30 . In the present embodiment, for example, when the element constituting the particles 20 is gold (Au) or platinum (Pt), the substrate 30 is treated with aqua regia (or hot aqua regia) immediately after the step of forming the non-through holes. ), the particles 20 can be dissolved and removed (particle removal step). When the element constituting the particles 20 is silver (Ag), the particles 20 are dissolved by immersing the base material 30 in concentrated nitric acid immediately after the step of forming the non-through holes, thereby removing the silver (Ag). becomes possible (particle removal step).

It is preferable that an oxide film forming step similar to the oxide film forming step of the first embodiment is performed after the above-described particle removing step is performed and before the placement step of the first embodiment is performed. It is a mode. By the oxide film forming step, 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. It is possible to make it easier for the object 40 to be measured to enter.

Although the mechanism is not clear at this time, when the measurement substrate 300 of the present embodiment is adopted, the effect of the measurement substrate 100 of the first embodiment is less than the effect of the element of the object 40 to be measured. The present inventors have confirmed that the detection sensitivity for the intensity of the emission line is slightly lowered.

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 non-through holes 10 in this embodiment. Note that the results shown in FIG. 12 are obtained when the immersion time in the tetrachloroauric (III) acid aqueous solution in the dispersing step of the first embodiment is 60 seconds. In other words, it is the difference between the measurement substrate 100 of the first embodiment and the measurement substrate 300 of the third embodiment. The conditions are the same except for the presence or absence of the particle removal step. As shown in FIG. 12, the emission line intensity (“Y4” in FIG. 12) of the element of the object to be measured 40 when the particle removal step is performed is the same as that of the measurement substrate 100 of the first embodiment. It was confirmed that the intensity of the light emitted by the measurement object 40 (“Y1” in FIG. 12) decreased to about half.

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

<Modified example of the third embodiment>
A measurement substrate 400, which is an example of the measurement substrate of this modified example, and a manufacturing method thereof will be described. In the measurement substrate 400 of the present embodiment, the non-through holes 10 are completely or substantially completely filled with the object 40 to be measured in the region where the object 40 to be measured and the substrate 30 are in contact. Except for , it is the same as the measurement substrate 300 of the third embodiment. Therefore, the description overlapping with the first embodiment or the third embodiment can be omitted.

FIG. 13 is a schematic diagram showing a cross section of the measurement substrate 400 in this modified example. As shown in FIG. 13, the measurement substrate 400 of the present embodiment includes a substrate 30 having a surface of a porous silicon layer including non-through holes 10, and an object 40 to be measured is partially arranged on the surface of the substrate 30. It is In addition, in the present embodiment, in the region where the object 40 to be measured and the base material 30 are in contact, the object 40 to be measured placed on the base material 30 completely covers the non-through hole 10 by the object 40 to be measured. or almost completely filled. It should be noted that no or almost no particles 20 are present at the bottoms of these non-through holes 10 .

Here, it is a preferred aspect that an oxide film forming step similar to the oxide film forming step of the first embodiment is performed before the disposing step of the first embodiment is performed also in this embodiment. . By the oxide film forming step, 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. It is possible to make it easier for the object 40 to be measured to enter.

Even when the measurement substrate 400 of the present embodiment is adopted, the same effects as those of the measurement substrate 100 of the first embodiment or the measurement substrate 300 of the third embodiment can be obtained. .

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

FIG. 14 is a schematic diagram showing a cross section of the measurement substrate 500 in this embodiment. As shown in FIG. 14, in the present embodiment, at least part of the non-through hole 10 is not completely filled with the object 40 to be measured, as in the measurement substrate 100 of the first embodiment. A measurement substrate 500 is manufactured.

Even when the measurement substrate 500 of the present embodiment is adopted, the same effects as those of the measurement substrate 100 of the first embodiment can be obtained.

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

Further, in each of the above-described embodiments and modified examples, the non-through hole 10 having an aspect ratio of 3.5 or more, which is obtained by dividing the depth of the non-through hole 10 by its opening width, is employed. According to the knowledge of the present inventor based on the relationship between the etching time and the emission line intensity shown in FIG. The aspect ratio is preferably 5 or more, more preferably 10 or more, and even more preferably 15 or more.

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

The present invention can detect the intensity of the emission line of the element of the object to be measured with high sensitivity even if the amount of the object to be measured is very small. It can be widely used in various industries such as investigating the components of contaminated water inside and outside the nuclear reactor or unknown liquid.

REFERENCE SIGNS LIST 10 non-through hole 20 particle 30 base material 40 object to be measured 50 glass substrate 80 silicon oxide layer 90 laser beam irradiation unit 91 mirror 92 stage 93 CMOS camera 94a dichroic mirror 94b imaging lens 94c objective lens 96 optical fiber bundle 97 achromatic lens 98a Spectroscope 98b Detector 99 Controller 100, 200, 300, 400, 500 Base material for measurement 900 Emission spectroscopic analyzer

Claims (5)

The silicon layer of the base material, on which at least the silicon layer is formed as the uppermost layer, is a non-through hole with an opening width of 1 nm or more and 1 μm or less, and the aspect ratio obtained by dividing the depth by the opening width is 3. .having a porous surface containing 5 or more of said blind pores;
For measuring the emission line intensity of an element possessed by the object to be measured when the object to be measured arranged to cover at least a part of the non-through hole is irradiated with a laser beam,
Substrate for measurement. comprising a silicon oxide layer on at least a portion of the silicon layer;
The substrate for measurement according to claim 1. At least one selected from the group consisting of gold (Au), silver (Ag), and platinum (Pt) is disposed on at least a portion of the bottom of the non-through hole.
The substrate for measurement according to claim 1 or 2. The silicon layer of the base material, on which at least the silicon layer is formed as the uppermost layer, is a non-through hole with an opening width of 1 nm or more and 1 μm or less, and the aspect ratio obtained by dividing the depth by the opening width is 3. a measurement substrate having a porous surface containing 5 or more of the non- through holes, on which the object to be measured is arranged so as to cover at least a part of the non-through holes;
a laser beam irradiation unit for irradiating the object to be measured with a laser beam;
a measurement unit that measures the emission line intensity of an element possessed by the object to be measured when the laser beam is irradiated;
Emission spectrometer. The silicon layer of the base material, on which at least the silicon layer is formed as the uppermost layer, is a non-through hole with an opening width of 1 nm or more and 1 μm or less, and the aspect ratio obtained by dividing the depth by the opening width is 3. arranging an object to be measured so as to cover at least a portion of the non-through holes of the substrate having a porous surface containing 5 or more of the non- through holes;
a laser light irradiation step of irradiating the object to be measured with a laser light;
a measuring step of measuring the emission line intensity of the element possessed by the object to be measured;
Emission spectroscopy method.

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