JP2022018494A - Substrate for phosphor detection, and method for manufacturing substrate for phosphor detection - Google Patents

Abstract

To provide a substrate for phosphor detection with which it is possible to improve the sensitivity of detecting a phosphor and a method for manufacturing the substrate for phosphor detection.SOLUTION: Further included is an insulating layer 12, with which the frequency distribution of surface heights in a sea-island structure where clearance of a metal projection 11 constitutes the sea includes a first peak where the most frequent surface height is maximum among all peaks and a second peak where the most frequent surface height is next to the first peak among all peaks, the average width in the sea-island structure of a first projection 21 constituting the first peak being 200 nm or less, the average width in the sea-island structure of a second projection 22 constituting the second peak being smaller than the average width of the first projection 21, the insulating layer covering the surface of the metal projection 11 in thickness of 1 nm to 5 nm inclusive and forming in the clearance of the metal projection 11 a gap 3 of 1 nm to 20 nm inclusive where a probe can be arranged.SELECTED DRAWING: Figure 1

Description

The present invention relates to a base material for detecting a phosphor, which is a base material used for detecting a phosphor, and a method for producing a base material for detecting a phosphor.

Microarrays are known as instruments for collecting various biochemical information such as base sequences and antibody structures. The microarray is provided with a probe that is a detector on the surface of the detection unit, and the binding between the sample contained in the sample and the probe is used for sample detection. For example, the probe DNA immobilized on the detection unit is used for DNA detection that can hybridize with the probe DNA. The antibody immobilized on the detection unit is used for detecting an antigen containing an epitope recognized by the antibody (see, for example, Patent Documents 1 to 3).

For the detection of the binding between the probe and the sample, for example, a sample labeled with a fluorescent dye is used, and the presence or absence of fluorescence is treated as the presence or absence of the sample. If the metal film that generates the standing wave of surface plasmon is located on the surface of the detection part, the enhanced fluorescence due to surface plasmon resonance is detected, so that a small amount of sample can be detected with high sensitivity ( For example, see Patent Document 4).

Japanese Unexamined Patent Publication No. 2003-149240 Special Table 2006-512917 Gazette Japanese Unexamined Patent Publication No. 2012-070654 Japanese Unexamined Patent Publication No. 2015-021889

On the other hand, as described in Patent Document 4, in a configuration in which an evanescent wave by a diffraction grating is used to generate surface plasmon resonance, surface plasmon polaritons are diffused in a two-dimensional direction along the interface between the metal film and the dielectric. It ends up. As a result, the above-mentioned configuration still leaves room for improvement as a configuration for detecting a small amount of sample with high sensitivity.

An object of the present invention is to provide a base material for detecting a phosphor and a method for producing a base material for detecting a phosphor, which can improve the detection sensitivity of the phosphor.

The base material for detecting a phosphor for solving the above-mentioned problems includes a base material main body having a base material surface made of a dielectric or a semiconductor, and a metal protrusion which is a plurality of aggregates located on the base material surface. , And the frequency distribution of the surface height in the sea island structure in which the surfaces of the plurality of metal protrusions are formed and the gap between the metal protrusions is the sea, the most frequent surface height within the peak is the total peak. A first peak having the largest peak among all peaks and a second peak having the most frequent surface height next to the first peak among all peaks are provided, and the first protrusion constituting the first peak. The average width of the sea island structure is 200 nm or less, and the average width of the second protrusion constituting the second peak in the sea island structure is smaller than the average width of the first protrusion and is 1 nm or more and 5 nm or less. An insulating layer having a thickness covering the surface of the metal protrusion, further comprising the insulating layer for partitioning a gap of 1 nm or more and 20 nm or less in which a probe can be placed.

In the method for manufacturing a base material for detecting a phosphor to solve the above problems, a plurality of metal protrusions are provided on a base material surface made of a dielectric or a semiconductor, and the surfaces of the plurality of metal protrusions are formed. The frequency distribution of the surface height in the sea island structure with the gap between the metal protrusions as the sea is the first peak in which the most frequent surface height in the peak is the largest among all the peaks, and the most frequent surface in the peak. A second peak having a height next to the first peak among all the peaks is provided, and the average width of the first protrusion constituting the first peak in the sea island structure is 200 nm or less. A method for manufacturing a base material for detecting a phosphor, wherein the average width of the second protrusion constituting the second peak in the sea island structure is smaller than the average width of the first protrusion. 1 A first film forming step of forming a metal film, a first heating step of forming a plurality of aggregates by splitting and agglomeration by heating of the first metal film, and a gap between the surface of the agglomerates and the agglomerates. A second film forming step of forming a second metal film, a second heating step of forming the metal protrusion by breaking and aggregating the second metal film by heating, and 1 nm or more and 5 nm on the surface of the metal protrusion. The present invention includes a third film forming step of forming an insulating layer having the following thickness and partitioning a gap of 1 nm or more and 20 nm or less in which a probe can be placed in the gap of the metal protrusion by the insulating layer.

According to each of the above configurations, the surface of the base material made of a dielectric or a semiconductor and the metal protrusion enhance the fluorescence emitted by the phosphor by surface plasmon resonance. At this time, the range in which surface plasmon resonance can occur is within the range corresponding to the bottom surface of the metal protrusion, and the surface plasmon polariton is localized in the range of the bottom surface. In other words, localized surface plasmon resonance occurs. Moreover, the insulating layer covering the surface of the metal protrusion suppresses the transfer of fluorescence to the metal protrusion as energy (hereinafter, also referred to as quenching). As a result, diffusion and quenching of surface plasmon polaritons are suppressed and fluorescence is locally enhanced. Therefore, with the above configuration, it is possible to detect strong fluorescence in a narrow range due to the formation of local surface plasmon polaritons, as compared with the configuration in which weak fluorescence over a wide range in which surface plasmon polaritons are diffused is detected. Therefore, the detection sensitivity of the phosphor can be improved.

In the base material for detecting a fluorescent substance, the base material main body may be provided with a groove recessed from the edge of the metal protrusion in the gap of the metal protrusion.
For example, when the substrate surface is a flat surface and the probe is fixed to the plane, the position of the phosphor bound to the probe is farther from the substrate surface as the molecular size of the probe is larger. In this respect, in the case of the configuration provided with the groove, the position where the probe is fixed is lower than the substrate surface by the groove depth, and the position of the phosphor bound to the probe is the groove depth. Only approach the interface between the metal protrusion and the base material body. As a result, the intensity of the fluorescence incident on the interface between the metal protrusion and the main body of the base material is increased, so that the detection sensitivity of the phosphor can be further improved.

In the fluorophore detection substrate, the bottom surface of the groove may be covered with a coupling agent capable of binding to the substrate body and the probe. According to this configuration, it is easy to fix the probe to the bottom surface of the groove, so that it is easy to arrange the probe in the gap.

In the base material for detecting a phosphor, the difference between the most frequent surface height of the first peak and the most frequent surface height of the second peak may be 5 nm or more and 60 nm or less. According to this configuration, it is easy to separately form the metal protrusions constituting the second peak in the gaps between the metal protrusions constituting the first peak, and the metal protrusions constituting the first peak and the metal protrusions constituting the first peak. It is also easy to form a gap of 1 nm or more and 20 nm or less in the gap with the metal protrusion constituting the second peak.

In the base material for detecting a phosphor, the base material surface has a periodic uneven structure, the pitch of the periodic uneven structure is 160 nm or more and 1220 nm or less, and the sheet resistance of the sea island structure is 3 × 10. It may be ² Ω / □ or more and 5 × 10 ⁴ Ω / □ or less. According to this configuration, the electric field enhancing effect by the localized surface plasmon resonance and the electric field enhancing effect by the propagation type surface plasmon resonance are combined, and it becomes possible to obtain a stronger electric field enhancing effect.

The fluorescent substance detection base material may be provided with the probe in a portion of the insulating layer that partitions the gap.

FIG. 2 is a cross-sectional view showing an example of a base material for detecting a fluorescent substance together with a probe and a fluorescent substance. A scanning tunneling microscope image showing an example of the surface structure of a substrate for detecting a phosphor. The plan view which shows an example of the metal protrusion provided with the base material for detecting a fluorescent substance. The graph which shows an example of the frequency distribution of the surface height in the base material for fluorescent substance detection. (A), (b) and (c) are process diagrams showing an example of a method for manufacturing a base material for detecting a phosphor. (A) (b) is a process diagram which shows an example of the manufacturing method of the base material for fluorescent substance detection.

Hereinafter, an embodiment of the base material for detecting a fluorescent substance will be described with reference to the drawings.
As shown in FIG. 1, the base material for detecting a phosphor is a base material main body 10 having a base material surface 10S, a plurality of metal protrusions 11 located on the base material surface 10S, and the surface of each metal protrusion 11. An insulating layer 12 covering the 11S is provided.

The base material surface 10S is made of a dielectric or a semiconductor. The base material main body 10 is a single-layer base material main body made of the same material as the base material surface 10S, or a multilayer base material provided with a layer made of a material different from the base material surface 10S in the lower layer of the base material surface 10S. It is the main body. The thickness of the base material body 10 is, for example, 0.1 mm or more and 5.0 mm or less.

The dielectric is an inorganic dielectric or an organic dielectric. The inorganic dielectric is, for example, various glasses, sapphire, quartz and the like. The organic dielectric is, for example, polymethylmethacrylate, polycarbonate, polystyrene, polyolefin, polyester and the like. The semiconductor is, for example, silicon, silicon carbide, or the like.

The base material body 10 includes a groove 10G recessed from the peripheral edge of the metal protrusion 11. The groove 10G extends along the edge of the metal protrusion 11 and is located below the gap of the metal protrusion 11. The groove 10G may have a U-shape in which the groove width decreases toward the bottom surface of the groove 10G in a cross section orthogonal to the extending direction of the groove 10G, or the groove width increases toward the bottom surface of the groove 10G. It may be dovetail groove-shaped.

The insulating layer 12 covers the surface 11S of each metal protrusion 11, the groove side surface of the groove 10G, and the groove bottom surface of the groove 10G. The insulating layer 12 has a shape that follows the surface 11S of each metal protrusion 11, the groove side surface of the groove 10G, and the groove bottom surface of the groove 10G. The material constituting the insulating layer 12 is, for example, a silicon oxide, a silicon nitride, or a silicon oxynitride.

The insulating layer 12 partitions a gap 3 for arranging the probe 1. The gap 3 is a region including the inside of the groove 10G. The probe 1 is a biomolecule that can chemically bind to the fluorescent substance 2 which is a target labeled with a fluorescent dye. The gap 3 has a size capable of containing the probe 1 and the phosphor 2. The probe 1 is fixed to the insulating layer 12 located on the bottom surface of the groove 10G. The probe 1 is, for example, a single-stranded DNA, RNA, protein, antibody, and small molecule compound having a sequence complementary to the phosphor 2.

The thickness of the insulating layer 12 is substantially constant on each of the surface 11S of each metal protrusion 11, the groove side surface of the groove 10G, and the groove bottom surface of the groove 10G. The thickness of the insulating layer 12 is, for example, 1 nm or more and 5 nm or less, preferably 1 nm or more and 3 nm or less. When the thickness of the insulating layer 12 is 1 nm or more and 5 nm or less, the absorption of fluorescence by the insulating layer 12 is suppressed, and quenching in which the fluorescence is transferred to the metal protrusion 11 as energy is suppressed. When the thickness of the insulating layer 12 is 1 nm or more and 3 nm or less, the above-mentioned effect can be obtained, and the formation of the insulating layer 12 and the formation of the gap 3 become easy.

The bottom surface of the groove 10G is covered with the coupling agent 31. The coupling agent 31 is a material that can be bonded to the base material body 10 or the insulating layer 12 and also to the probe 1. The coupling agent 31 increases the force for fixing the probe 1 to the bottom surface of the groove 10G, and facilitates the probe 1 to be arranged in the gap 3. The thickness of the coupling agent 31 is preferably such that the entire groove 10G is not filled with the coupling agent 31. The coupling agent 31 is, for example, a silane coupling agent, and is preferably configured as a monomolecular layer film because it does not fill the groove 10G and easily forms a gap 3.

As shown in FIG. 2, the surfaces 11S of the plurality of metal protrusions 11 form a sea island structure with the gaps between the metal protrusions 11 as the sea. The sea-island structure is composed of a first island structure S1 in which a plurality of metal protrusions 11 are connected and a second island structure S2 in which the metal protrusions 11 are interrupted. The first island structure S1 is a structure in which a plurality of metal protrusions 11 are not interrupted, and the metal protrusions 11 adjacent to each other are not separated by a gap. The second island structure S2 is a structure in which metal protrusions 11 adjacent to each other are separated by a gap.

The material constituting the metal protrusion 11 is obtained by jointly obtaining the electric field enhancing effect by surface plasmon resonance between the metal protrusion 11 and the base material main body 10. The material constituting the metal protrusion 11 is, for example, gold, silver, aluminum, copper, platinum, two or more kinds of alloys thereof, or a combination of two or more kinds thereof.

[Surface height]
The height of the metal protrusion 11 is the height of the surface 11S where the height of the bottom surface 11B of the metal protrusion 11 is “0”. The height of the metal protrusion 11 can be measured by various instruments such as a scanning electron microscope, a transmission electron microscope, and an atomic force microscope (hereinafter, also referred to as AFM).

On the other hand, the surface height of the metal protrusion 11 is the height of the surface 11S whose position higher than the bottom surface 11B of the metal protrusion 11 is “0”. The surface height of the metal protrusion 11 is determined by AFM so that the frequency distribution of the surface height in the sea island structure can be statistically processed.

Since the resolution measured by the AFM is as small as 1 nm or less in the height direction, it can reflect not only the thickness of the metal protrusion 11 but also errors such as warpage, distortion, and unevenness of the base material body 10. The measured value of the surface height by the AFM measurement includes an error due to the difference between the ideal plane and the base material surface 10S. The frequency distribution of the surface height in the sea-island structure is obtained by arithmetically averaging the distributions of the surface heights measured at three different points in order to suppress the variation caused by the above error. It is obtained by a simple moving average (n = 15) of the height distribution at intervals of 0.6 nm.

An example of AFM measurement conditions for obtaining the distribution of surface height in the sea-island structure is shown below.
-Explorer tip diameter: 2 nm or more and 5 nm or less-Exploration tip angle: The angle from the tip to 200 nm is less than 20 °-Measurement range: 500 nm
-Scan rate: 0.3Hz or more and 1.0Hz or less-Sampling rate: 256 x 256 pixels or more and 512 x 512 pixels or less An example that satisfies the above probe shape is, for example, Super Sharp Silicon Force Modulation Mode SSS-FMR manufactured by Nano World AG. -10.

The gap of the metal protrusion 11 is, for example, narrower than the diameter of the tip of the probe, and includes the size when the probe of the AFM is caught on the metal protrusion 11 above the base material surface 10S. The minimum height "0" in the AFM measurement is a height determined by the narrowest width into which the AFM probe enters in the gap of the metal protrusion 11, and is higher than the base material surface 10S. That is, the surface height of the metal protrusion 11 measured by AFM is the height of the surface 11S whose position higher than the bottom surface 11B is "0".

[Island shape]
As shown in FIG. 2, the surface 11S of the metal protrusion 11 has an independent peak shape or a mountain peak shape.
As shown in FIG. 3, the distinction between the mountain range and the independent peak is based on the shape of a virtual ellipse (hereinafter, also referred to as the circumscribed ellipse R) circumscribing the judgment target S2T in the AFM image. The circumscribed ellipse R has the smallest area among the ellipses circumscribed to the judgment target S2T. Specifically, the major axis Rmax and the minor axis Rmin of the circumscribing ellipse R, and the length W1 in the minor axis direction in the determination target S2T (for example, the length A, the length B, and the length C shown in FIG. 3) are The determination target S2T that satisfies any of the following conditions 1 to 4 is a mountain range. The judgment target S2T that does not satisfy any of the following conditions 1 to 4 is an independent peak.
-Condition 1: 4 <major diameter Rmax / minor diameter Rmin.
Condition 2: 3 <major diameter Rmax / minor axis Rmin ≦ 4 and a length W1 of 40% or less of the minor axis Rmin is recognized in the range of 60% or more of the major axis.
Condition 3: 2 <major diameter Rmax / minor diameter Rmin ≦ 3 and a length W1 of 30% or less of the minor axis Rmin is recognized in the range of 60% or more of the major axis.
Condition 4: 1 <major diameter Rmax / minor axis Rmin ≦ 2 and a length W1 of 20% or less of the minor axis Rmin is recognized in the range of 60% or more of the major axis.

When the circumscribed ellipse R cannot be set, the distinction between the mountain peak shape and the independent peak shape conforms to the shape of a virtual ellipse (hereinafter, also referred to as an inscribed ellipse) inscribed in the judgment target S2T in the AFM image. The inscribed ellipse has the largest area among the ellipses inscribed in the judgment target S2T. Specifically, the metal protrusion 11 in which the length W1 of 20% or less of the minor axis of the inscribed ellipse is recognized in the range of 60% or more of the major axis of the inscribed ellipse is mountainous. The metal protrusion 11 in which the length W1 of 20% or less of the minor axis of the inscribed ellipse is not recognized in the range of 60% or more of the major axis of the inscribed ellipse is an independent peak.

[peak]
The plurality of metal protrusions 11 include a plurality of first protrusions 21 and a plurality of second protrusions 22. The first protrusion 21 constitutes the first peak P1 in the frequency distribution of the surface height in the sea island structure. The second protrusion 22 constitutes the second peak P2 in the frequency distribution of the surface height in the sea island structure. The height of the highest first top 21a of any first protrusion 21 is higher than the height of the highest second top 22a of all the second protrusions 22. The maximum value of the surface height in any first protrusion 21 is higher than the maximum value of the surface height of all the second protrusions 22.

As shown in FIG. 4, the frequency distribution of the surface height in the sea island structure includes the first peak P1, the second peak P2, and the third peak P3. The frequency distribution of the surface height indicates the frequency of the surface height for each surface height. The first peak P1 and the second peak P2 have a maximum frequency, and the maximum value is sandwiched between the minimum frequency values. The half width of the first peak P1 and the second peak P2 is 2 nm or more.

In the first peak P1, the surface height with the highest frequency within the peak (hereinafter, also referred to as the most frequent surface height) is the highest among all peaks. The metal protrusion 11 constituting the first peak P1 is the first protrusion 21. The most frequent surface height at the first peak P1 is the first most frequent surface height T1. The first most frequent surface height T1 is preferably 10 nm or more and 100 nm or less, and more preferably 10 nm or more and 50 nm or less.

In the second peak P2, the most frequent surface height in the peak is the second largest among all peaks after the first peak. The metal protrusion 11 constituting the second peak P2 is the second protrusion 22. The most frequent surface height at the second peak P2 is the second most frequent surface height T2. The second most frequent surface height T2 is preferably 5 nm or more and 42 nm or less, and more preferably 5 nm or more and 30 nm or less.

In the third peak P3, the most frequent surface height in the peak is the smallest among all the peaks. The structure constituting the third peak P3 is a gap of the first protrusion 21, a gap between the first protrusion 21 and the second protrusion 22, and a gap of the second protrusion 22. The most frequent surface height at the third peak P3 is the third most frequent surface height T3. The third most frequent surface height T3 is preferably 2 nm or more and 12 nm or less, and more preferably 2 nm or more and 10 nm or less. The frequency distribution of the surface height is such that the third peak P3 is not included, for example, the third most frequent surface height T3 is "0", or the lowest surface height at the second peak P2 is "0". , The frequency of the surface height may gradually increase.

The difference between the first most frequent surface height T1 and the second most frequent surface height T2 is preferably 3 nm or more and 60 nm or less, and more preferably 7 nm or more and 25 nm or less. The difference between the first most frequent surface height T1 and the second most frequent surface height T2 reflects the mode of the difference between the height of the first protrusion 21 and the height of the second protrusion 22. When the difference between the first most frequent surface height T1 and the second most frequent surface height T2 is within the above range, it is preferable from the viewpoint that the formation of the second island structure S2 is easy.

The difference between the second most frequent surface height T2 and the third most frequent surface height T3 is preferably 5 nm or more and 40 nm or less, and more preferably 5 nm or more and 15 nm or less. The difference between the second most frequent surface height T2 and the third most frequent surface height T3 reflects the difference between the height of the second protrusion 22 and the minimum height "0" in the AFM measurement. That is, the difference between the second most frequent surface height T2 and the third most frequent surface height T3 reflects the height of the second protrusion 22 to no small extent. When the difference between the second most frequent surface height T2 and the third most frequent surface height T3 is within the above range, it is preferable from the viewpoint that a gap between the first protrusion 21 and the second protrusion 22 is easily formed. ..

The difference between the first most frequent surface height T1 and the third most frequent surface height T3 is preferably 10 nm or more and 100 nm or less, more preferably 10 nm or more and 98 nm or less, and 10 nm or more and 30 nm or less. Is even more preferable. The difference between the first most frequent surface height T1 and the third most frequent surface height T3 reflects the difference between the height of the first protrusion 21 and the minimum height "0" in the AFM measurement. That is, the difference between the first most frequent surface height T1 and the third most frequent surface height T3 reflects the height of the first protrusion 21 in no small measure. When the difference between the first most frequent surface height T1 and the third most frequent surface height T3 is within the above range, it is preferable from the viewpoint that the second island structure S2 is easily formed.

The first boundary height L1 in the frequency distribution of the surface height is the boundary between the first peak P1 and the second peak P2. The first boundary height L1 is the least frequent surface height between the first most frequent surface height T1 and the second most frequent surface height T2. The first boundary height L1 is preferably 7 nm or more and 40 nm or less, and more preferably 10 nm or more and 25 nm or less.

The second boundary height L2 in the frequency distribution of the surface height is the lowest surface height at the second peak P2. The second boundary height L2 is, for example, the least frequent surface height between the second most frequent surface height T2 and the third most frequent surface height T3. The second boundary height L2 is preferably 3 nm or more and 25 nm or less, and more preferably 3 nm or more and 15 nm or less.

[Mean width]
The average width of the metal protrusion 11 is the average width of the first protrusion 21, and is the average value of the length W1 in the AFM image. In the calculation of the mean width, the portion of the first protrusion 21 that is higher than the second boundary height L2 (the first island region H1 shown in FIG. 1) is treated as the first protrusion 21. Further, a portion of the second protrusion 22 higher than the second boundary height L2 (second island region H2 shown in FIG. 1) is treated as the second protrusion 22.

The measurement target for obtaining the mean width is any five first protrusions 21 that intersect any of the two diagonal lines defined in the AFM image. The measurement target for obtaining the average width is, for example, selected in order from the one closest to the intersection of the diagonal lines in the AFM image. If the number of measurement targets does not reach 5 in one AFM image, the same processing is performed on the AFM images acquired at different locations of the same sample, and the process is repeated until the total score reaches 5. .. The arithmetic mean value of the length W1 in the five selected measurement objects is the mean width of the metal protrusion 11.

The average width of the independent peak-shaped first protrusion 21 is the average value of the maximum value of the length W1 and the minimum value of the length W1 in the long axis direction in the first island region H1. If there are multiple maximums or multiple minimums, they are all arithmetic mean values. In the case of the independent peak-shaped first protrusion 21, it is the arithmetic mean value of the length A and the length C which are the maximum values of the length W1 and the length B which is the minimum value of the length W1. ) / 3 ”is the average width of the first protrusion 21.

The mean width of the mountainous peak-shaped first protrusion 21 is obtained by using the length between two points where the orthogonal line with respect to the central curve in the first island region H1 and the contour line of the first island region H1 intersect. .. The central curve is a curve along the extending direction of the first protrusion 21 in the AFM image, and is a virtual curve drawn inside the first island region H1. The orthogonal line to the central curve is a straight line that passes through the arbitrary point and is orthogonal to the tangent line of the central curve at an arbitrary point on the central curve. The central curve is a curve drawn so that the central curve is located at the center between the two points between the two points where the orthogonal line with respect to the central curve and the contour line of the first island region H1 intersect.

In the measurement of the average width at the mountainous peak-shaped first protrusion 21, first, an orthogonal line having the maximum length between two points where the contour of the first island region H1 and the orthogonal line intersect is determined. Next, the length between the two points is measured every 20 nm from the starting point toward both ends of the central curve, starting from the orthogonal line that maximizes the length between the two points. Then, the average width at the mountainous first protrusion 21 is obtained by arithmetically averaging all the lengths including the length between the two points on the orthogonal line as the starting point. If the central curve is long, the number of measurement points for the length between the two points is limited to 25 points.

However, if the length between two points on the orthogonal line as the starting point exceeds 1.5 times the length at a position 20 nm away from both sides of the orthogonal line, the orthogonal line as the starting point is the main trunk portion. It is considered to be a branching part that branches from, and the orthogonal line with the next maximum length is defined as the new starting point. At this time, the point where the central curve of the branch portion and the central curve of the main trunk portion intersect is the branch point. The measurement points of the length at the branch part are the length along the central curve of the main trunk part from the orthogonal line to the branch point as the new starting point, and the central curve of the branch part from the branch point toward the tip of the branch. It is assumed that the total length along the line is an integral multiple of 20 nm. The first protrusion 21 having a branch portion also has a length between two points up to 25 points in order from the one closest to the starting point, including the length between the two points on the orthogonal line newly used as the starting point. The length is measured, and the arithmetic mean value of the length between all two points is taken as the mean width.

Approximately, the average width of the first protrusion 21 can be obtained by using an SEM image instead of the AFM image. For example, an SEM image (910 nm × 1210 nm) of 100,000 times is acquired, two diagonal lines are drawn on the acquired SEM image, and five diagonal lines intersecting with each other are arbitrarily selected. The average width is obtained in the same manner as in the case based on the AFM image. The method of distinguishing whether the first protrusion 21 is a mountain range or an independent peak and how to obtain the average width in each case is the same as the case based on the AFM image. However, since the contour line of the first island region H1 is not determined in the SEM image, the contour line of the first protrusion 21 is treated as the contour line of the first island region H1 in the measurement of the average width using the SEM image.

The average width of the first protrusion 21 is 200 nm or less. The average width of the independent peak-shaped first protrusion 21 is preferably 180 nm or less, more preferably 5 nm or more and 130 nm or less, and further preferably 10 nm or more and 80 nm or less. The average width of the mountainous peak-shaped first protrusion 21 is preferably 150 nm or less, more preferably 5 nm or more and 100 nm or less, and further preferably 10 nm or more and 60 nm or less. When the average width of the first protrusion 21 is 200 nm or less, the electric field enhancing effect by the localized surface plasmon resonance can be easily obtained.

Returning to FIG. 1, the base material for detecting a phosphor is a sea region between the first island region H1 and another first island region H1 and between the first island region H1 and the second island region H2. Determine H3. The sea region H3 is a portion lower than the second boundary height L2 in the gap of the metal protrusion 11. The average width of the sea region H3 is preferably 1 nm or more and 20 nm or less, more preferably 1 nm or more and 10 nm or less, and further preferably 1 nm or more and 7 nm or less. The narrower the mean width of the sea region H3, the shorter the distance between the phosphor and the metal protrusion 11, the attenuation of fluorescence is suppressed, and the electric field enhancement effect by the localized surface plasmon resonance is likely to be obtained.

The mean width of the sea region H3 is the length between two points where the orthogonal line with respect to the central curve in the sea region H3 and the contour line of the sea region H3 intersect, the same as the mean width of the mountainous first protrusion 21. Is obtained using.

If the average width of the sea region H3 is narrow, the sheet resistance value at 25 ° C. on the surface 11S of the metal protrusion 11 becomes low. Therefore, the sheet resistance value at 25 ° C. on the surface 11S of the metal protrusion 11 is preferably low, preferably 3Ω / □ or more and 200Ω / □ or less, and more preferably 10Ω / □ or more and 150Ω / □ or less. The sheet resistance (Ω / □) of the metal protrusion 11 is the electric resistance value when a current flows from one end to the opposite end in a square region of an arbitrary size of the metal protrusion 11 under the condition of 25 ° C. Is.

The depth GD of the groove 10G is, for example, 10 nm or more and 100 nm or less, and more preferably 20 nm or more and 80 nm or less. The average width of the groove 10G is, for example, 5 nm or more and 50 nm or less, and more preferably 10 nm or more and 40 nm or less. When the average width of the groove 10G is 5 nm or more, it is easy to arrange the probe 1 inside the groove 10G. When the average width of the groove 10G is 50 nm or less, the distance between the phosphor 2 arranged in the groove 10G and the metal protrusion 11 becomes an appropriate size in which the attenuation of fluorescence is suppressed. In particular, when the average width of the groove 10G is 40 nm or less, a high electric field enhancing effect due to localized surface plasmon resonance can be easily obtained.

The mean width of the groove 10G is the same as the mean width of the first protrusion 21 of the mountain range, using the length between two points where the orthogonal line with respect to the center curve in the groove 10G and the contour line of the groove 10G intersect. Desired. The AFM image for measuring the average width of the groove 10G is obtained by using, for example, a sample from which the metal protrusion 11 and the insulating layer 12 have been removed from the phosphor detection base material.

[Action of substrate for fluorescent substance detection]
The metal protrusion 11 and the base material body 10 enhance the fluorescence emitted by the phosphor 2 by surface plasmon resonance. At this time, the size of the interface between the metal protrusion 11 and the base material main body 10 is a size corresponding to the bottom surface 11B of the metal protrusion 11, and the surface plasmon polaritone is localized in the range of the bottom surface 11B. It causes so-called localized surface plasmon resonance. Further, the insulating layer 12 covering the surface 11S of the metal protrusion 11, the groove side surface of the groove 10G, and the groove bottom surface of the groove 10G has a thickness of 1 nm or more, whereby fluorescence is used as energy for the metal protrusion 11. Suppresses quenching by moving to and extinguishing. As a result, the surface plasmon polaritons do not diffuse widely in the two-dimensional direction, the fluorescence is locally enhanced, and the phosphor 2 can be detected with high sensitivity.

The height position of the phosphor 2 bound to the probe 1 becomes farther from the fixed end of the probe 1 as the molecular size of the probe 1 increases. If the substrate surface 10S is a flat surface and the flat surface is the fixed end of the probe 1, the height position of the phosphor 2 bonded to the probe 1 is such that the larger the molecular size of the probe 1, the more the metal protrusion 11 And the interface between the base material body 10 and the base material body 10. On the other hand, in the case of the base material main body 10 provided with the groove 10G, the fixed end of the probe 1 is separated from the interface between the metal protrusion 11 and the base material main body 10 by the groove depth of the groove 10G, and is separated from the probe 1. The height position of the bonded phosphor 2 can approach the interface between the metal protrusion 11 and the base material body 10 by the depth GD of the groove 10G. As a result, the intensity of the fluorescence incident on the interface between the metal protrusion 11 and the base material main body 10 is improved, and the detection sensitivity of the phosphor 2 can be further improved.

[Manufacturing method of base material for fluorescent substance detection]
The method for producing a substrate for detecting a phosphor has a first film forming step, a first heating step, a second film forming step, a second heating step, an etching step, and a third film forming step.

As shown in FIG. 5A, in the first film forming step, the first metal film 111 is formed on the base material surface 10S of the base material main body 10. The material constituting the first metal film 111 is a material constituting the metal protrusion 11, and is gold, silver, aluminum, copper, platinum, two or more alloys thereof, or a combination of two or more kinds thereof. Is. The method for forming the first metal film 111 on the base material surface 10S is, for example, a dry method or a wet method such as electrolytic plating or electroless plating. The dry method is, for example, various physical vapor deposition methods and various chemical vapor deposition methods.

The thickness of the first metal film 111 is preferably 2 nm or more and 60 nm or less, and more preferably 3 nm or more and 30 nm or less. When the thickness of the first metal film 111 is 2 nm or more, the distance between the agglomerates formed in the first heating step does not widen too much. When the thickness of the first metal film 111 is 60 nm or less, the aggregate formed in the first heating step tends to have an independent peak shape or a mountain peak shape.

As shown in FIG. 5B, in the first heating step, the first metal film 111 is divided and aggregated by heating to form a plurality of first aggregates 211. Metals containing gold, silver, aluminum, copper, platinum and the like generally have low surface free aggregation energy in the molten state. Therefore, the first metal film 111 is divided by heating above the melting point and subsequently aggregates.

The melting point of a metal is lower than that of a bulk metal due to the melting point depression phenomenon. That is, the thinner the thickness of the first metal film 111, the lower the melting point. If the thickness of the metal film is several tens of nm, the melting point depression phenomenon becomes even more remarkable. For example, the melting point of bulk gold is 1064 ° C., but the melting point of a thin gold film having a thickness of 10 nm or less is lowered to 150 ° C. or higher and 200 ° C. or lower.

The heating temperature in the first heating step differs depending on the type of metal, but when gold is used as the material constituting the first metal film 111, it is preferably 100 ° C. or higher and 600 ° C. or lower, more preferably 200 ° C. or higher and 400 ° C. or lower. preferable. When silver is used as the material constituting the first metal film 111, it is preferably 80 ° C. or higher and 600 ° C. or lower, and more preferably 200 ° C. or higher and 400 ° C. or lower.

The heating time in the first heating step varies depending on the type of metal and the heating temperature. For example, when gold is used as the material constituting the first metal film 111 and heated at 300 ° C., it is 10 seconds or more and 60 minutes or less. Is preferable. When silver is used as a material constituting the first metal film 111 and heated at 280 ° C., it is preferably 10 seconds or more and 50 minutes or less.

The higher the heating temperature in the first heating step and the longer the heating time, the higher the degree of aggregation, and the plurality of metal protrusions 11 tend to have independent independent peaks. On the other hand, the lower the heating temperature and the shorter the heating time, the more difficult it is for aggregation to proceed, and the plurality of metal protrusions 11 tend to have a mountainous shape.

The heating method in the first heating step is heating by a direct fire of a muffle furnace, an electric furnace, an oven including a furnace, a hot plate, an infrared heating device, a gas burner, or the like. It is preferable that the first heating step is performed in an atmosphere of an inert gas such as argon or nitrogen to suppress oxidation of the metal by oxygen in the atmosphere.

As shown in FIG. 5C, in the second film forming step, the second metal film 112 is formed on the surface of the first aggregate 211 and the base material surface 10S exposed from the first aggregate 211. The material constituting the second metal film 112 is a material constituting the metal protrusion 11, and is gold, silver, aluminum, copper, platinum, two or more alloys thereof, or a combination of two or more kinds thereof. Is. The material constituting the second metal film 112 is preferably the same as the material constituting the first metal film 111. As a method for forming the second metal film 112, the same method as in the first film forming step can be adopted.

The thickness of the second metal film 112 is preferably 2 nm or more and 60 nm or less, and more preferably 3 nm or more and 30 nm or less. Further, the thickness of the second metal film 112 is preferably equal to or thinner than the thickness of the first metal film 111. When the thickness of the second metal film 112 is 2 nm or more, the second protrusion 22 is formed at a preferable height after the second heating step. When the thickness of the second metal film 112 is 60 nm or less, the metal protrusion 11 is easily divided and the sea region H3 is likely to be formed during the second heating step. When the second metal film 112 is thinner than the first metal film 111, it is easy to lower the heating temperature in the second heating step to be lower than the heating temperature in the first heating step.

As shown in FIG. 6A, in the second heating step, the second metal film 112 is divided and aggregated by heating to form a plurality of second aggregates 212. The aggregate in which the second metal film 112 is laminated on the surface of the first aggregate 211 is the first protrusion 21. The structure in which the second metal film 112 is aggregated on the base material surface 10S is the second protrusion 22. The heating condition in the second heating step is that the second metal film 112 can be aggregated by heating, but the position of the first aggregate 211 is displaced or the condition is such that further aggregation does not proceed. preferable.

In reality, since the second metal film 112 is heated above the melting point, the influence of heating the first aggregate 211 cannot be completely eliminated, but the change in the position and shape of the metal protrusion 11 is minimized. Is preferable. Specifically, it is preferable to make the heating temperature of the second heating step lower than the heating temperature of the first heating step, shorten the heating time, or both of them.

The heating temperature in the second heating step differs depending on the type of metal, but when gold is used as the material constituting the second metal film 112, it is preferably 50 ° C. or higher and 400 ° C. or lower, and 90 ° C. or higher and 250 ° C. or lower. preferable. When silver is used as the material constituting the second metal film 112, it is preferably 40 ° C. or higher and 400 ° C. or lower, and more preferably 70 ° C. or higher and 250 ° C. or lower.

The heating time in the second heating step varies depending on the type of metal and the heating temperature. For example, when gold is used as the material constituting the second metal film 112 and heated at 150 ° C., it takes 10 seconds or more and 60 minutes or less. preferable. When silver is used as the material constituting the second metal film 112 and heated at 140 ° C., it is preferably 10 seconds or more and 50 minutes or less.

The heating method in the second heating step is, for example, any one of the methods exemplified in the heating method in the first heating step, and is preferably the same as the heating method in the first heating step. As in the first heating step, the second heating step is preferably performed in an atmosphere of an inert gas to suppress oxidation of the metal by oxygen in the atmosphere.

As shown in FIG. 6B, in the etching step, the base material surface 10S is etched using the metal protrusion 11 as a mask, and a groove 10G is formed in the gap of the metal protrusion 11. The method of etching the base material surface 10S is a wet method or a dry method. The etchant used in the wet method is, for example, hydrofluoric acid, an aqueous solution of ammonium fluoride, or a combination thereof.

In the third film forming step, the insulating layer 12 is formed on the metal protrusion 11, the groove side surface of the groove 10G, and the groove bottom surface of the groove 10G. The method for forming the insulating layer 12 is, for example, an atomic layer deposition method in which adsorption of a raw material gas, exhaust of a surplus raw material gas, adsorption of a reaction gas, and exhaust of a surplus reaction gas are repeated. According to the formation of the insulating layer 12 using the atomic layer deposition method, the surface 11S of each metal protrusion 11, the groove side surface of the groove 10G, and the groove bottom surface of the groove 10G are uniformly covered with the insulating layer 12 and It is easy to make the thickness of the insulating layer 12 1 nm or more and 5 nm or less.

[Example]
The base material for detecting a fluorescent substance and the method for producing the base material for detecting a fluorescent substance will be described below.
(Example 1)
As the base material body 10, a silicon substrate was cut into a square plate having a side of 30 mm by a diamond cutter. As a silicon substrate, φ4inch Polishing Wafer (Type / Dopan: P / Boron, Crystal Axis: <100>, Resistivity (ohm-cm): 1-100, Thickness (um): 505-545, manufactured by GlobalWarers Co., Ltd. ) Was used. Next, the substrate body 10 was ultrasonically cleaned with acetone for 10 minutes, and then the substrate body 10 was ultrasonically cleaned with distilled water for 10 minutes.

Next, a sputtering device (manufactured by Hitachi, Ltd .: E-1030) was used with the polished surface of the base material body 10 after cleaning as the base material surface 10S, and a gold thin film having an average thickness of 8 nm was formed as the first metal film 111. After forming, the first film forming step was performed. At this time, gold was used as a constituent material of the target when performing sputtering, the pressure was set to 8 Pa, the current value was set to 15 mA, and the film forming time was set to 30 seconds.

Next, using a hot plate (manufactured by AS ONE: CHP-170DF) on which a copper plate having a thickness of 5 mm was placed, the base material body 10 on which the first metal film 111 was formed was placed on the copper plate. Then, the first metal film 111 formed on the base material main body 10 was heated to perform the first heating step of forming the first aggregate 211. At this time, the temperature of the copper plate when heating the base material main body 10 was set to 290 ° C., the surface of the base material main body 10 in contact with the copper plate was set to the surface opposite to the base material surface 10S, and the heating time was set to 90 seconds. Then, the base material main body 10 after the first heating step was moved onto a metal plate having a temperature of 20 ° C. and cooled.

Next, a sputtering device (manufactured by Hitachi, Ltd .: E-1030) was used as the second metal film 112 toward the surface of the first aggregate 211 and the substrate surface 10S exposed from the first aggregate 211. A gold thin film having a thickness of 8 nm was formed, and a second film forming step was performed. At this time, the target, pressure, current value and film forming time at the time of sputtering were set to the same conditions as in the first film forming step.

Next, using the hot plate (manufactured by AS ONE: CHP-170DF) used in the first heating step, the base material body 10 on which the second metal film 112 was formed was placed on the copper plate. Then, the second metal film 112 formed on the base material main body 10 was heated to perform a second heating step of forming the first protrusion 21 and the second protrusion 22. At this time, the temperature of the copper plate when heating the base material main body 10 was set to 110 ° C., the surface of the base material main body 10 in contact with the copper plate was set to the surface opposite to the base material surface 10S, and the heating time was set to 60 seconds. Then, the base material main body 10 after the second heating step was moved onto a metal plate having a temperature of 20 ° C. and cooled.

Using the base material main body 10 after the second heating step, an SEM image of the surface and an AFM image under the above-mentioned example of AFM measurement conditions were taken. As a result of measuring the average width of the first protrusion 21 using the SEM image, the average width of the independent peak-shaped first protrusion 21 is 44 nm, and the average width of the mountain range first protrusion 21 is 35 nm. rice field. Further, as a result of measuring the distribution of the surface height using the AFM image, the first peak surface height T1 which is the most frequent surface height of the first peak P1 and the most frequent surface height of the second peak P2 are used. The difference from a certain second mode surface height T2 was 13 nm.

Next, using a dry etching apparatus (manufactured by Tokyo Electron Limited: ME510I), the base material body 10 on which the first protrusion 21 and the second protrusion 22 are formed is used as a mask on the base material surface. An etching step of etching 10S to form a groove 10G was performed. At this time, the pressure at the time of etching was set to 1.0 Pa, the antenna power was set to 300 W, the bias power was set to 100 W, and the etching time was set to 10 seconds. Further, as the etching gas, 40 sccm of carbon tetrafluoride and 10 sccm of chlorine were used.

Next, a silicon oxide film having a thickness of 3 nm was formed on the base material body 10 after the etching step in which the groove 10G was formed by using an atomic layer deposition method, and a third film forming step was performed. From the above, the base material for fluorescent substance detection of Example 1 was obtained.

(Example 2)
The metal type of Example 1 is changed to silver, specifically, in the first film forming step and the second film forming step, the constituent material of the target when performing sputtering is changed to silver, and the first heating step is also performed. The heating time of the second heating step was set to 30 seconds, the heating time of the second heating step was set to 20 seconds, and the same as in Example 1 except for these, the substrate for detecting the phosphor of Example 2 was prepared.

[Comparison example]
(Comparative Example 1)
The etching step of Example 1 is omitted, and the other steps are the same as in Example 1 to prepare the fluorophore detection substrate of Comparative Example 1, that is, the fluorophore detection group having no groove 10G. I got the wood.

(Comparative Example 2)
The second film forming step and the second heating step of the first embodiment are omitted, and the other steps are the same as those of the first embodiment to prepare the base material for detecting the phosphor of Comparative Example 2, that is, A base material for detecting a phosphor was obtained by using the first aggregate 211 as a mask in the etching process.

(Comparative Example 3)
The third film forming step of Example 1 is omitted, and the other steps are the same as in Example 1 to prepare the fluorophore detection substrate of Comparative Example 3, that is, fluorescence without the insulating layer 12. A substrate for body detection was obtained.

[evaluation]
As a microarray using the fluorophore detection substrate of Example 1, the probe DNA was fixed to the substrate body 10 after the third film forming step, and a 1-channel microarray was prepared by the following procedure to obtain the probe DNA. The fluorescence enhancement intensity after hybridization was measured in hybridization-capable DNA detection.

First, the base material body 10 of each example was immersed in a poly-L-lysine solution for 1 hour and then dried to obtain a microarray for evaluation. As shown in Table 1, the second film forming step to the third film forming step are omitted, and another base material body 10 that is not immersed in the poly-L-lysine solution is used for measuring the fluorescence enhancing intensity. Prepared as an example (control) microarray.

Then, a DNA solution of 1 μl or more and 2 μl or less was added dropwise to the base material body 10 of each example, and dried in an atmosphere of 80 ° C. for 1 hour. Then, ultraviolet rays were irradiated for 20 minutes using an ultraviolet irradiator to obtain a base body 10 having been spotted.

Next, the base material body 10 of each example was immersed in a blocking solution for 5 minutes, washed with pure water, and dried in an atmosphere of 95 ° C. for 2 minutes. Then, the base material body 10 of each example was washed with ethanol three times and air-dried to obtain a blocking-treated microarray.

The biotin-bound DNA was then amplified by the polymerase chain reaction (PCR) and then mixed with a hybridization solution to suppress non-specific displacement binding, heated at 95 ° C. for 3 minutes, and then ice-cooled for 2 minutes. , Target DNA was prepared.

Then, the target DNA mixed with the hybridization solution was added dropwise to the microarray of each example, hybridization was performed, and then the DNA was washed with a solution containing a surfactant and air-dried. Then, streptavidin-Cy3 was added dropwise as a labeling reagent to the microarray of each example, and the mixture was allowed to stand in an environment of 30 ° C. for 30 minutes and then washed again with a solution containing a surfactant.

Then, using a spectrophotometer (spectrophotometer V-770: manufactured by JASCO Corporation), the reflectance of each example of the microarray was measured at 5 degrees with respect to the normal direction of the substrate surface 10S. At this time, the excitation wavelength to be incident on the substrate surface 10S was set to 550 nm, and the fluorescence wavelength centered on 570 nm was observed. Further, the integrated value of the peaks obtained by the microarray using the base material of the reference example was set to 100, and the integrated value of the peaks obtained by the microarray using the base materials of each example and the comparative example was standardized.

As a result, as shown in Table 1, the fluorescence intensity obtained from the microarray prepared by the fluorescence detection substrate of Example 1 was 10E5. The microarray prepared from the fluorescence detection substrate of Example 2 in which the metal type was changed to silver was 10E5, which was about the same as that of Example 1. On the other hand, the fluorescence intensity obtained from the microarray prepared by the fluorescence detection substrate of Comparative Example 1 not provided with the groove 10G was 10E3. Further, the fluorescence intensity obtained from the microarray prepared by the fluorescence detection substrate of Comparative Example 2 which was etched using the first aggregate 211 as a mask, and the fluorescence detection of Comparative Example 3 which does not have the insulating layer 12. The fluorescence intensity obtained from the microarrays prepared from the substrate was 10E2, which was about the same as that of the reference example. That is, in the configuration without the insulating layer 12 or the configuration without the fine groove 10G such as using the second aggregate 212 as a mask, only the same degree of fluorescence intensity as the reference example can be obtained, and the second aggregate 212 can be obtained. It was found that even if the insulating layer 12 is provided, the configuration without the minute groove 10G only increases the fluorescence intensity by about an order of magnitude as compared with the reference example. Further, by providing the fine groove 10G with the second aggregate 212 as a mask and the insulating layer 12 covering the metal protrusion 11 and the groove 10G, it is possible to increase the fluorescence intensity by about three orders of magnitude as compared with the reference example. Was recognized as.

As described above, according to the above embodiment, the effects listed below can be obtained.
(1) The base material main body 10 and the metal protrusion 11 can obtain an electric field enhancing effect by localized surface plasmon resonance, and can also suppress quenching by the insulating layer 12. As a result, the diffusion and quenching of surface plasmon polaritons are suppressed, and the detection sensitivity of the phosphor can be improved.

(2) Since the position of the phosphor 2 bonded to the probe 1 approaches the interface between the metal protrusion 11 and the base material body 10 by the depth GD of the groove 10G, the metal protrusion 11 and the base material body 10 The amount of fluorescent light incident on the interface with and can be increased.

(3) Since the coupling agent covering the bottom surface of the groove 10G facilitates fixing the probe 1 to the bottom surface of the groove 10G, it also becomes easy to arrange the probe 1 in the gap 3.
The above embodiment can also be modified and implemented as follows.

[Frequency distribution of surface height]
-In the frequency distribution of surface height in the sea island structure, the number of peaks may be four or more. From the viewpoint of enabling stable production of the fluorophore detection substrate, the number of peaks is preferably 5 or less, and particularly preferably 3 peaks. In the manufacturing method in which the number of peaks is 4 or more, for example, a step of further forming a metal film of 2 nm or more and 60 nm or less between the second heating step and the third film forming step and the step of heating the metal film are performed. A step of dividing and aggregating is added separately.

[Surface 11S]
The surface 11S of the metal protrusion 11 can also be provided with metal nanoparticles. The shape of the metal nanoparticles is, for example, spherical, needle-shaped, flake-shaped, polyhedral-shaped, ring-shaped, hollow-shaped, a shape in which the dielectric is wrapped in metal, a dendritic crystal, or any other indefinite shape. The average primary particle diameter of the metal nanoparticles is preferably 1 nm or more and 100 nm or less, and more preferably 3 nm or more and 50 nm or less. The average primary particle size of the metal nanoparticles is an average value obtained from the measurement of the primary particle size using the SEM image. Instead of the measurement using the SEM image, the average primary particle size may be measured by a transmission electron microscope, an AFM, or a particle size distribution meter by a dynamic light scattering method. The material constituting the metal nanoparticles is, for example, gold, silver, aluminum, copper, platinum, an alloy of two or more of these, and the like.

-The shortest distance between the metal nanoparticles adjacent to each other is preferably 1 nm or more and 20 nm or less, and more preferably 1 nm or more and 10 nm or less. When the shortest distance is 1 nm or more and 20 nm or less, it is easy to obtain the electric field enhancing effect by the localized surface plasmon resonance in the gaps of the metal nanoparticles, and it is also easy to arrange the probe in the gaps of the metal nanoparticles. The shortest distance is obtained by actual measurement using SEM images.

-The method for arranging the metal nanoparticles is, for example, a spray coating method, a spin coating method, a dip coating method, a drop casting method, or the like. The step of arranging the metal nanoparticles is included between the step of forming the metal protrusion 11 and the third film forming step of forming the insulating layer 12.

[Base material surface 10S]
The base material surface 10S can also be provided with a periodic uneven structure. The periodic uneven structure is a structure in which protrusions or recesses are periodically arranged in a one-dimensional direction or a two-dimensional direction. The one-dimensional lattice structure in which the protrusions are periodically arranged in the one-dimensional direction is, for example, a line-and-space structure in which the protrusions are arranged in parallel with each other. The shape of the cross section orthogonal to the extending direction of the ridge may be, for example, a polygonal shape such as a triangle, a rectangle, or a trapezoid, a U-shape, or a derivative shape based on them.

The two-dimensional lattice structure in which the protrusions are periodically arranged in the two-dimensional direction is, for example, a square lattice structure in which the arrangement directions are orthogonal to each other, and an angle formed by two adjacent directions in three directions is 60 °. It has a triangular lattice structure. The shape of the protrusion located on the lattice point is, for example, a cylindrical shape, a conical shape, a truncated cone shape, a sinusoidal shape, a hemispherical shape, a substantially hemispherical shape, an ellipsoidal shape, or a derivative shape based on them. And so on.

The gap between the protrusions is a nearly flat surface. The height of the protrusion is, for example, preferably 15 nm or more and 150 nm or less, and more preferably 30 nm or more and 80 nm or less. When the height of the protrusion is 15 nm or more and 150 nm or less, the surface 11S of the metal protrusion 11 functions as a diffraction grating that follows the periodic uneven structure, and the electric field enhancement effect by the propagation type surface plasmon resonance can be easily obtained.

The pitch of the protrusions is the horizontal distance between the center points of the protrusions adjacent to each other. For the measurement of the pitch of the protrusions, the surfaces of five periodic uneven structures separated from each other by 100 μm or more are used. An AFM image of 5 μm × 5 μm is acquired for the five measurement areas, and the distance between the center points of the nine points arbitrarily extracted from each AFM image is measured. The pitch of the protrusions in the periodic uneven structure is preferably 160 nm or more and 1220 nm or less, and more preferably 200 nm or more and 800 nm or less.

In order to induce the propagation type surface plasmon on the metal protrusion 11, the sheet resistance of the metal protrusion 11 on the surface 11S is preferably low, preferably 3 × 10 ² Ω / □ or more and 5 × 10 ⁴ Ω / □ or less. 3, 3 × 10 ² Ω / □ or more 5 × 10 ³ Ω / □ is more preferable. If the sheet resistance on the surface 11S of the metal protrusion 11 is within this range, the metal protrusion 11 is a continuous film that is not completely divided even if there is a gap in the metal protrusion 11. I can say. The fact that the sheet resistance of the metal protrusion 11 is within this range indicates that the metal protrusion 11 is a semi-continuous film that is not completely divided even if a non-deposited region is present. Further, the fact that the sheet resistance of the metal protrusion 11 is within this range means that even if a non-deposited region exists, the width thereof is 0.1 nm or more and 15 nm or less, and more specifically, 0.1 nm or more and 5 nm or less. Means that

When the metal protrusion 11 is completely divided, the sheet resistance of the surface 11S is not less than 5000Ω / □. Even if a non-deposited region exists, the metal protrusion 11 as a whole is a semi-continuous film, which makes it possible to generate propagation-type surface plasmons on the metal protrusion 11, due to the superposition of surface electric fields. It is easy to obtain a non-linear optical effect.

The periodic element, which is a protrusion or a recess provided in the periodic uneven structure, has a width and a height sufficiently larger than the average width of the metal protrusion 11. Further, the width provided by the gap of the periodic element is also sufficiently larger than the average width provided by the metal protrusion 11. The metal protrusion 11 is arranged so as to follow the shape of the uneven surface formed by the surface of the periodic uneven structure. The surface height distribution in the sea-island structure is the distribution of the surface height excluding the fluctuation due to the surface height of the periodic uneven structure.

The periodic uneven structure obtains the electric field enhancing effect by the propagation type surface plasmon resonance in addition to the above-mentioned localized surface plasmon resonance. Then, the electric field enhancing effect due to the localized surface plasmon resonance and the electric field enhancing effect due to the propagation type surface plasmon resonance are combined to make it possible to obtain a stronger electric field enhancing effect.

The base material body 10 may be configured not to have a groove 10G. That is, the base material surface 10S may be a flat surface having no groove 10G, and the plurality of metal protrusions 11 may be located on the flat base material surface 10S. From the viewpoint that the height of the phosphor 2 and the height of the interface between the base material main body 10 and the metal protrusion 11 are matched, it is preferable that the base material main body 10 includes a groove 10G.

S1 ... 1st island structure S2 ... 2nd island structure S2T ... Judgment target T1 ... 1st most frequent surface height T2 ... 2nd most frequent surface height T3 ... 3rd most frequent surface height 1 ... Probe 2 ... Phosphorant 3 ... Gap 10 ... Base material body 10G ... Groove 10S ... Base material surface 11 ... Metal protrusion 11S ... Surface 11B ... Bottom surface 12 ... Insulation layer 21 ... First protrusion 22 ... Second protrusion 31 ... Coupling agent 111 ... 1st metal film 112 ... 2nd metal film 211 ... 1st agglomerate 212 ... 2nd agglomerate.

Claims (7)

A base material body having a base material surface made of a dielectric or a semiconductor,
A metal protrusion, which is a plurality of aggregates located on the surface of the base material, is provided.
In the frequency distribution of the surface height in the sea island structure in which the surfaces of the plurality of metal protrusions are composed and the gap between the metal protrusions is the sea, the most frequent surface height in the peak is the largest among all the peaks. It comprises a first peak and a second peak having the most frequent surface height next to the first peak among all peaks.
The average width of the first protrusion constituting the first peak in the sea island structure is 200 nm or less, and the average width of the second protrusion constituting the second peak in the sea island structure is the first protrusion. Less than the average width of
An insulating layer having a thickness of 1 nm or more and 5 nm or less that covers the surface of the metal protrusion, and further comprising the insulating layer that partitions a gap of 1 nm or more and 20 nm or less in which a probe can be placed in the gap. Material. The fluorescent substance detection base material according to claim 1, wherein the base material main body is provided with a groove recessed from the edge of the metal protrusion in the gap of the metal protrusion. The fluorescent substance detection base material according to claim 2, wherein the bottom surface of the groove is covered with a coupling agent that can be bonded to the base material body and the probe. The base material for fluorescent substance detection according to any one of claims 1 to 3, wherein the difference between the most frequent surface height of the first peak and the most frequent surface height of the second peak is 5 nm or more and 60 nm or less. The base material surface has a periodic uneven structure and has a periodic uneven structure.
The pitch of the periodic uneven structure is 160 nm or more and 1220 nm or less.
The fluorescent substance detection base material according to any one of claims 1 to 4, wherein the sheet resistance of the sea-island structure is 3 × 10 ² Ω / □ or more and 5 × 10 ⁴ Ω / □ or less. The base material for fluorescent substance detection according to any one of claims 1 to 5, wherein the probe is provided in a portion of the insulating layer that partitions the gap. A surface height in a sea-island structure in which a plurality of metal protrusions are provided on a substrate surface made of a dielectric or a semiconductor, and the surfaces of the plurality of metal protrusions are formed and the gap between the metal protrusions is the sea. The frequency distribution is the first peak in which the most frequent surface height in the peak is the largest among all the peaks, and the second peak in which the most frequent surface height in the peak is the second largest among all the peaks after the first peak. The average width of the first protrusion constituting the first peak in the sea island structure is 200 nm or less, and the average width of the second protrusion constituting the second peak in the sea island structure is 200 nm or less. Is a method for manufacturing a substrate for detecting a phosphor, which is smaller than the average width of the first protrusion.
The first film forming step of forming the first metal film on the substrate surface and
The first heating step of forming a plurality of aggregates by splitting and agglutination by heating the first metal film, and
A second film forming step of forming a second metal film between the surface of the aggregate and the gap between the aggregates,
The second heating step of forming the metal protrusion by the division and aggregation of the second metal film by heating,
A third layer in which an insulating layer having a thickness of 1 nm or more and 5 nm or less is formed on the surface of the metal protrusion, and a gap of 1 nm or more and 20 nm or less in which a probe can be placed is partitioned by the insulating layer in the gap of the metal protrusion. A film forming process and a method for manufacturing a base material for detecting a phosphor.

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