JP2008168396A - Minute structural body and its manufacturing method, device for raman spectroscopy, raman spectroscopic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a minute structural body having furthermore high electric field intensifying effect. <P>SOLUTION: The minute structural body 1 comprises a dielectric substance base material 11 which has a plurality of minute holes 12 therein, and has some of the minute holes 12 opened at least on the surface 11s of the base material. At least part of a plurality of the minute holes 12 is filled with metallic bodies 21 having the size capable of inducing localized plasmon by being irradiated with light L. A plurality of metallic particles 22 having the size capable of inducing localized plasmon by being irradiated with light L are fixed to non-opened portions of a plurality of the minute holes 12 on the surface 11s of the base material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a microstructure in which a metal capable of inducing localized plasmons is formed on a dielectric base material having a plurality of micropores therein and having the plurality of micropores open at least on the surface of the base material. The present invention relates to a manufacturing method, and a Raman spectroscopic device and a Raman spectroscopic apparatus using the fine structure.

  Sensor devices and devices for Raman spectroscopy that use localized plasmon resonance on metal surfaces are known. Raman spectroscopy is a method of obtaining a spectrum of Raman scattered light (Raman spectrum) obtained by dispersing scattered light generated by irradiating a substance with single wavelength light. In Raman spectroscopy, there is Raman spectroscopy using an electric field enhanced by localized plasmon resonance, called surface enhanced Raman (SERS), in order to enhance weak Raman scattered light.

  Localized plasmon resonance is a phenomenon in which, when light is incident on a light-irradiated surface with a nano-order concavo-convex structure, free electrons resonate with the electric field of the light and vibrate to generate a strong electric field around the convex part. It is known that a higher electric field enhancing effect is exhibited when the metal convex portions are close to each other.

As a Raman spectroscopic device capable of obtaining a high electric field enhancement effect, it is preferable that metal particles capable of inducing localized plasmons are immobilized on a light irradiation surface in close proximity to a high density. As a microstructure used for such a Raman spectroscopic device, an anodized metal body (Al, etc.) is anodized to form a part of a metal oxide layer (Al ₂ O _3, etc.), and the process of anodization In other words, a structure in which a metal is filled in a plurality of fine holes that are naturally formed inside the metal oxide layer and open on the surface of the metal oxide layer has been proposed.

  The micropores formed by anodization are controlled in nanometer order, and the pores can be arranged almost regularly via a dielectric. Therefore, by filling each micropore with a metal, On the light irradiation surface, it is possible to fix the nano-order metal bodies by arranging them in a regular order without contacting them.

  Patent Document 1 discloses a structure in which a bottom portion of a filling metal in a microscopic hole is exposed and a surface on the bottom side is used as a light scattering surface, and Patent Document 2 discloses a surface on a side where the micropore is closed. A structure in which a metal is disposed in a recess using the unevenness of the dielectric portion is disclosed.

  Patent Document 3 discloses a structure in which metal particles are arranged closer to each other in the micropores by expanding the micropores by pore-wide processing and narrowing the pitch of the micropores.

In Patent Documents 4 to 7, a structure in which the distance between the filled metals is reduced to obtain a high electric field enhancement effect has a head protruding from the surface of the metal oxide layer (mushroom). Structure), a fine structure is disclosed in which the distance between adjacent heads is made closer to obtain an electric field enhancement effect by an effective localized plasmon.
JP 2006-83450 A JP 2006-83451 A JP 2006-38506 A JP 2005-172569 A JP 2005-307341 A JP 2005-336538 A JP 2006-89788 A

  As described above, various microstructures have been proposed, but the present inventors have invented a microstructure capable of obtaining a higher electric field enhancement effect.

That is, an object of the present invention is to provide a microstructure capable of obtaining a higher electric field enhancement effect and a manufacturing method thereof without requiring a complicated manufacturing process.
It is another object of the present invention to provide a Raman spectroscopic device and a Raman spectroscopic apparatus using the fine structure.

The microstructure of the present invention includes a dielectric substrate having a plurality of micropores therein and at least a plurality of micropores opened at the surface of the substrate, and the substrate surface side is irradiated with light. In the microstructure
At least a part of the plurality of micropores is filled with a metal body having a size capable of inducing localized plasmon by the light irradiation, and the non-openings of the plurality of micropores on the surface of the base material are filled. A plurality of metal particles having a size capable of inducing localized plasmons by light irradiation are fixed to the portion.

  When a very thin metal film is formed on the non-opening portions of the plurality of micropores on the surface of the substrate, the film may not have a film shape and may have a structure in which fine metal particles are scattered. In this specification, such fine metal particles are not regarded as metal particles.

In the microstructure of the present invention, it is preferable that an average particle diameter of the plurality of metal particles is less than the wavelength of the light. Moreover, it is preferable that an average diameter of the plurality of micropores is less than the wavelength of the light.
In the present specification, “particle diameter” means the maximum diameter of the particles, and “micropore diameter” means the maximum diameter of the micropores.

  In the microstructure of the present invention, the minimum height difference between the surface of the base material and the surface of the metal body filled in the plurality of micropores is equal to or less than the average particle diameter of the plurality of metal particles. Is preferred.

  In a preferred aspect of the microstructure of the present invention, the dielectric substrate is made of a metal oxide body obtained by anodizing at least a part of the anodized metal body, and the plurality of micropores are the anode. Examples thereof include those formed in the metal oxide body during the oxidation process.

  The metal particles are formed by forming a metal film of the same component as the metal particles on the surface of the base material, and then aggregating the constituent metals of the metal film into particles by heat treatment. It is preferable.

The temperature of the heat treatment is preferably not less than the melting point of the metal film and less than the melting point of the dielectric substrate.
In the present specification, the “melting point of the metal film” means the melting point of the film itself, not the melting point of the bulk metal constituting the metal film. Although details will be described later, the melting point lowering phenomenon occurs in the present invention, so that the melting point of the metal film is lower than the melting point of the bulk metal constituting the metal film.

  The Raman spectroscopic device of the present invention is a Raman spectroscopic device in which a sample is brought into contact with a surface, measurement light is incident on the sample, and Raman scattered light of the measurement light is detected. It is characterized by.

The Raman spectroscopic device of the present invention includes the Raman spectroscopic device of the present invention,
Light irradiation means for irradiating the surface of the Raman spectroscopic device with the measurement light;
Spectroscopic means for dispersing scattered light generated on the surface to obtain a spectrum of Raman scattered light is provided.

The method for producing a microstructure of the present invention includes a step (A) of preparing a dielectric substrate having a plurality of micropores therein and having the plurality of micropores opened at least on the substrate surface;
A step (B) of forming a metal film on non-opening portions of the plurality of micropores on the surface of the substrate;
Filling at least a part of the plurality of micropores with a metal body having a size capable of inducing localized plasmons;
A plurality of metal particles having a size capable of inducing localized plasmons in non-opening portions of the plurality of micropores on the surface of the base material by aggregating the constituent metals of the metal film by a heat treatment to form particles. And a step (D) of forming.

  In the said manufacturing method, as long as a process (D) is implemented after a process (B), the order to implement a process (B)-a process (D) will not be restrict | limited, There may be a process of simultaneous implementation. .

For example, as the step (C), when the step (B) is performed, the step (C-1) of partially filling the metal with the same component as the metal film into the plurality of fine holes at the same time,
The step of further filling the plurality of fine holes with the same or different metal as filled in step (C-1) to increase the amount of filled metal in the plurality of fine holes (C-2) ) And the like.

  The microstructure of the present invention includes a dielectric substrate having a plurality of micropores therein and at least a plurality of micropores opened on the surface of the substrate, and at least the plurality of micropores in the micropores. A metal body having a size capable of inducing localized plasmons is partially filled, and a plurality of metal particles having a size capable of inducing localized plasmons are fixed to non-opening portions of a plurality of micropores on the substrate surface. It is characterized by having.

  In such a configuration, the metal particles are fixed to the non-opening portions of the plurality of micropores on the surface of the substrate, so that the metal particles capable of inducing localized plasmons are fixed on the dielectric substrate in close proximity to each other at a high density. Can be made. Furthermore, in the microstructure of the present invention, localized plasmons are effectively generated on the surfaces of both the filled metal body in the micropores and the metal particles fixed to the substrate surface, and these interactions can also be expected.

  Therefore, in the microstructure of the present invention, combined with the above effects, an electric field enhancing effect higher than that of the conventional microstructure can be obtained. The fine structure of the present invention can be preferably used as a Raman spectroscopic device using localized plasmons. All the microstructures of the present invention can be manufactured by a simple manufacturing process by batch processing.

"Microstructures, Raman spectroscopy devices"
With reference to the drawings, a structure of a fine structure according to an embodiment of the present invention will be described. FIG. 1 is a sectional view in the thickness direction. FIG. 2 is a diagram showing a manufacturing process of the microstructure of the present embodiment. In FIG. 1A, the density of the metal particles 22 is shown to be lower than the actual density. Actually, as shown in FIG. 1B, the metal particles 22 can be arranged at high density.

  The microstructure 1 according to the present embodiment includes a dielectric substrate 11 formed on a conductor 13 and having a plurality of fine holes 12 opened on a substrate surface 11s. The dielectric substrate 11 has localized plasmons. The metal which can induce is formed. In the fine structure 1, the fine holes 12 are non-through holes that are opened substantially straight in the thickness direction from the front surface 11 s of the dielectric base material 11 and do not reach the back surface 11 r of the base material.

  In the present embodiment, as a metal capable of inducing localized plasmons, a metal body 21 having a size capable of inducing localized plasmons is filled in at least a part of the plurality of fine holes 12 of the dielectric substrate 11. A plurality of metal particles 22 having a size capable of inducing localized plasmons are fixed to non-opening portions of the plurality of micropores 12 on the substrate surface 11s.

  The microstructure 1 includes light with a wavelength capable of exciting localized plasmons in the metal body 21 filled in the micropores 12 and the metal particles 22 fixed to the substrate surface 11s with respect to the substrate surface 11s. Light L is irradiated. The fine structure 1 can be used as a device for Raman spectroscopy. In this case, the irradiated light L is single wavelength light emitted from a light source such as a laser.

  In the microstructure 1, localized plasmons are induced in the metal body 21 and the metal particles 22 by the light L, and an electric field enhancement effect by the localized plasmons is obtained.

  The localized plasmon phenomenon is a phenomenon in which the free electrons of the metal convex portion resonate with the electric field of the light and vibrate to generate a strong electric field around the convex portion. Any metal can be used, and the localized plasmon is more effective in gold (Au), silver (Ag), copper (Cu), platinum (Pt), nickel (Ni), titanium (Ti), etc. Are preferable, and gold (Au), silver (Ag), and the like are particularly preferable. The metal of the metal body 21 and the metal particle 22 may be the same component or different components, but the wavelength that generates localized plasmons varies depending on the type of metal, and therefore the same component is more effective. Localized plasmons can be generated.

  The average particle diameter d of the metal particles 22 may be any size that can induce localized plasmons, but is preferably less than the wavelength of the light L. The adjacent metal particles 22 are preferably separated from each other, and the average separation distance w is more preferably in the range of several nm to 10 nm. When the average separation distance is within the above range, the electric field enhancement effect by the localized plasmon effect can be effectively obtained.

  The filling form and size of the metal body 21 are not limited as long as localized plasmons can be induced, and may be filled without a gap from the bottom surface of the fine hole 12. May be spaced apart. Although the height difference between the substrate surface 11 s and the surface of the metal body 21 is not limited, the minimum height difference r is preferably equal to or less than the average particle diameter d of the metal particles 22. It is known that the protrusion length of the localized plasmon effect is about the metal particle diameter. Therefore, by setting the minimum height difference r to be equal to or less than the average particle diameter d of the metal particles 22, Since an interaction of localized plasmons occurs between the metal body 21 and the metal particles 22 on the substrate surface 11s, an effective electric field enhancing effect can be obtained.

Below, with reference to FIG. 2, the manufacturing method of the fine structure 1 of this embodiment is demonstrated. 2, (a) and (b) are perspective views, and (c) to (e) are cross-sectional views.
First, the laminated body of the conductor 13 and the dielectric base material 11 is prepared (process (A)). In this embodiment, as shown in FIGS. 2 (a) and 2 (b), the dielectric substrate 11 is made of an anodized metal body 10 that contains aluminum (Al) as a main component and may contain minute impurities. This is an alumina (Al ₂ O ₃ ) layer (metal oxide layer) obtained by anodizing a part of this. The conductor 13 is composed of a non-anodized portion of the anodized metal body 10 that remains without being anodized.

  The shape of the anodized metal body 10 is not limited, and examples thereof include a plate shape. Further, it may be used in a form with a support such as a layered metal object 10 to be anodized on a support.

  In anodization, for example, the metal body 10 to be anodized is used as an anode, carbon or aluminum is used as a cathode (counter electrode), these are immersed in an anodizing electrolyte, and a voltage is applied between the anode and the cathode. Can be implemented. The electrolytic solution is not limited, and an acidic electrolytic solution containing one or more acids such as sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, and amidosulfonic acid is preferably used.

  When the anodized metal body 10 shown in FIG. 2A is anodized, an oxidation reaction proceeds from the surface 10s (upper surface in the drawing) in a direction substantially perpendicular to the surface as shown in FIG. 2B. An alumina layer 11 is generated.

  The alumina layer 11 produced by anodic oxidation has a structure in which fine columnar bodies 14 having a substantially regular hexagonal shape in plan view are arranged adjacent to each other. A minute hole 12 is opened in a depth direction from the surface 10 s at a substantially central portion of each minute columnar body 14. Further, the bottom surfaces of the fine holes 12 and the fine columnar bodies 14 have rounded shapes as shown in the figure. The structure of the alumina layer produced by anodization is described in Hideki Masuda, “Preparation of mesoporous alumina by anodization and its application as a functional material”, Material Technology Vol.15, No.10, 1997, p.34, etc. Are listed.

  The anodizing conditions may be appropriately designed so that the non-anodized portion remains and the size of the fine holes 12 is within a range in which localized plasmons are induced in the filled metal body 21. When oxalic acid is used as the electrolytic solution, preferable conditions include an electrolytic solution concentration of 0.5 M, a liquid temperature of 15 ° C., and an applied voltage of 40 V. By changing the electrolysis time, the alumina layer 11 having an arbitrary layer thickness can be generated. If the thickness of the anodized metal body 10 before anodization is set to be thicker than the alumina layer 11 to be produced, the non-anodized part remains and is provided on the conductor 13 composed of the non-anodized part, An alumina layer 11 (dielectric substrate 11) in which a large number of micropores 12 having substantially the same shape in plan view are opened on the substrate surface 11s and are approximately regularly arranged can be obtained.

  Usually, the pitch between adjacent fine holes 12 can be controlled in the range of 10 to 500 nm, and the diameter of the fine holes can be controlled in the range of 5 to 400 nm. Japanese Patent Application Laid-Open Nos. 2001-9800 and 2001-138300 disclose methods for finely controlling the formation position and the hole diameter of fine holes. By using these methods, the micropores having an arbitrary pore diameter and depth within the above range can be arranged almost regularly.

  In the present embodiment, the average pitch P of the fine holes 12 is not limited, but is preferably less than the wavelength of the light L applied to the dielectric substrate 11. The microstructure 1 has an electric field enhancement effect due to the interaction between the metal body 21 filled in the micropores 12 and the metal particles 22 on the substrate surface 11s. Therefore, it is preferable that the micropores 12 are arranged almost regularly because an electric field enhancing effect with high in-plane uniformity can be obtained. In such a configuration, even if the area of the fine structure 1 is increased, a substantially uniform electric field enhancement effect can be obtained, and thus the area can be increased.

  Next, as shown in FIG. 2C, a metal film 20 having the same component as that of the metal particles 22 is formed on the non-opening portions of the plurality of micropores 12 on the substrate surface 11s (step (B)). The method for forming the metal film 20 is not limited, and for example, a vapor deposition method such as a vacuum deposition method, a sputtering method, a CVD method, a laser deposition method, and a cluster ion beam method is preferable. The metal film 20 may be formed at room temperature or under heating, and the film formation temperature is not limited.

  The film thickness dm of the metal film 20 is not particularly limited. When the film thickness dm of the metal film 20 is too small, it is difficult to stably form particles.

  As shown in FIG. 2C, when the step (B) is performed, the film forming material of the metal film 20 can be simultaneously filled in the bottoms of the plurality of fine holes 12 of the dielectric substrate 11 (see FIG. 2C). Step (C-1)). This filled metal becomes a part of the metal body 21.

  Next, as shown in FIG. 2 (d), the plurality of micropores 12 are further filled with the same component or different component metal filled in the step (C-1) in the plurality of micropores 12. The amount of filled metal is increased (step (C-2)). By performing the steps (C-1) and (C-2), the metal bodies 21 can be filled at a sufficient height in the plurality of fine holes 12, and the substrate surface 11s and the metal bodies 21 can be filled. The minimum height difference r with respect to the surface of the metal particles 22 can be made small, and preferably the minimum height difference r can be made equal to or less than the average particle diameter d of the metal particles 22.

  In the step (C-2), the method for increasing the amount of filled metal in the plurality of fine holes 12 is not particularly limited, and an electroplating method, an electroless plating method, or a solution containing a metal to be filled is placed in the fine holes 12. Examples thereof include a method of drying a solvent after pouring and a method of depositing a metal using a reducing agent.

  When metal filling is performed by electroplating, the metal starts to be deposited from the place where electricity easily flows. When the metal is filled in the fine holes 12 inside the dielectric substrate 11 as in the present embodiment, the conductor 13 functions as an electrode, so that the metal is introduced from the bottom of the fine hole 12 in the vicinity of the electrode. Although deposited, since it is a dielectric, it is difficult for electricity to flow, which may cause uneven filling. In this embodiment, by setting the process (B) and the process (C-1) as a manufacturing process performed before the process (C-2), the micropores are formed in the process (C-1) before the electroplating process. The bottom of 12 can be filled with metal so that the starting point of plating can be formed substantially uniformly in each fine hole 12. Therefore, the filling unevenness can be eliminated and the filled metal bodies 21 inside the plurality of fine holes 12 can be formed substantially uniformly, and the in-plane uniformity of the localized plasmon effect by the metal bodies 21 can be improved.

  Here, the case where the process (C) in which at least a part of the plurality of micro holes 12 is filled with the metal body 21 in the two stages of the process (C-1) and the process (C-2) has been described. Depending on the depth of the fine hole 12, the step (C-2) may not be performed. In addition, depending on the conditions, when performing step (B), the bottom of the micropores 12 may not be filled at the same time. In this case, only the step (C-2) is performed on the contrary. Become.

  Next, as shown in FIG. 2E, the constituent metals of the metal film 20 are agglomerated and formed into particles by heat treatment, and localized plasmons are formed in the non-opening portions of the plurality of micropores 12 on the substrate surface 11s. A plurality of metal particles 22 having a size that can be induced are formed (step (D)).

The heat treatment method of the metal film 20 is not limited, and examples thereof include annealing processes such as laser annealing, electron beam annealing, flash lamp annealing, thermal radiation annealing using a heater, and electric furnace annealing.
In the present embodiment, it is considered that the constituent metal of the metal film 20 is once melted by the heat treatment, and the melted metal naturally aggregates and forms particles on the surface 11s of the dielectric substrate 11 in the temperature lowering process.

  The heat treatment temperature is not limited as long as the constituent metals of the metal film 20 can be aggregated, and is preferably a temperature that is not lower than the melting point of the metal film 20 and lower than the melting point of the dielectric substrate 11. In the heat treatment step, it is necessary to agglomerate the constituent metals of the metal film 20 without melting the dielectric base material 11 and to form particles. Therefore, the heat treatment is performed in consideration of the melting points of the dielectric base material 11 and the metal film 20. It is necessary to set the temperature.

  In general, the melting point of the bulk metal is very high. For example, the melting point of the bulk body of Au, which is a preferable material of the metal film 20, is about 1064 ° C. The dielectric substrate 11 of the present embodiment is made of alumina, and its melting point is as high as 2050 ° C., but the melting point of the dielectric substrate is not necessarily higher than 1064 ° C.

  However, in the metal film 20 formed on the dielectric substrate 11, a melting point lowering phenomenon that melts at a temperature much lower than the melting point of the bulk metal occurs. The melting point lowering phenomenon of the metal film 20 occurs remarkably when the film thickness dm of the metal film 20 is nano-order. For example, there is a report that the melting point of Au is nanosized down to 2 nm, the melting point drops to around 300 ° C, and the physical properties change significantly (new development of nanoparticles and ultrafine particles-published by Toray Research Center). .

  The level of the melting point drop varies depending on the main component of the metal film 20 and the film thickness dm. By considering the actual melting point of the metal film 20 determined by the main component of the metal film 20 and the film thickness dm and the melting point of the dielectric substrate 11, a more suitable heat treatment temperature can be set. That is, the heat treatment temperature is preferably a temperature equal to or higher than the melting point of the metal film 20 and lower than the melting point of the dielectric substrate 11.

  As described above, when the method of forming the metal particles 22 by heat-treating the metal film 20 is used, the dielectric substrate 11 preferably has a melting point equal to or higher than the melting point of the metal film 20.

  As described above, the microstructure 1 of the present embodiment is manufactured. The manufacturing method described above includes everything from the manufacturing of the dielectric substrate 11 to the final step of obtaining the microstructure 1 in which the metal particles 22 are fixed to the non-opening portions of the micropores 12 on the substrate surface 11s. The process is a process of collectively processing the entire substrate. Therefore, even when the dielectric substrate 11 has a large area, the number of steps is not changed, and the fine structure 1 can be obtained by a very simple method. That is, in the fine structure 1 of the present embodiment, the area can be easily increased.

  The order of the steps (B) to (D) is not limited to the above order as long as the step (D) is performed after the step (B). For example, the microstructure 1 can be manufactured even if the step (C-2), the step (B), and the step (D) are sequentially performed.

  As described above, in the microstructure 1, localized plasmons are induced in the metal body 21 and the metal particles 22 by the irradiated light L, and an electric field enhancement effect by the localized plasmons is obtained. The electric field enhancement effect by localized plasmons is said to be 100 times or more at the localized plasmon resonance wavelength. Therefore, as the light L, it is preferable to use light having a wavelength that causes localized plasmon resonance in the metal body 21 and / or the metal portion 22.

  In the fine structure 1, when the dielectric substrate 11 is a translucent material such as anodized alumina, the light L is incident on the translucent body, and the conductor 13 and the metal particles 22 on the substrate surface 11 s. And an interference phenomenon occurs in the translucent body, causing an optical interference effect in which light of a certain wavelength is absorbed, and the electric field is enhanced on the substrate surface 11s. Further, when the conductor 13, the translucent portion, and the metal particles 22 on the substrate surface 11s form a resonance structure, resonance occurs at a specific wavelength due to multiple reflection (peak wavelength of multiple interference) and large absorption. Will result. The present inventors have found that the peak wavelength of multiple interference can be adjusted by the thickness of the translucent part (Japanese Patent Application No. 2006-149713, unpublished at the time of filing this patent application). By controlling the thickness of the body part, that is, the thickness of the dielectric substrate 11, the wavelength causing the localized plasmon of the metal body 21 and / or the metal particle 22 and the peak wavelength of multiple interference are substantially matched, A large electric field enhancement effect can be obtained.

  The microstructure 1 of the present embodiment includes a dielectric base material 11 having a plurality of micropores 12 therein and at least a plurality of micropores 12 opened at a base material surface 11s. A metal body 21 having a size capable of inducing localized plasmons is filled in at least a part of the micropores 12, and localized plasmons can be induced in non-opening portions of the plurality of micropores 12 on the substrate surface 11 s. A plurality of metal particles 22 having a size are fixed.

  In such a configuration, since the metal particles 22 are fixed to the non-opening portions of the plurality of micropores 12 on the substrate surface 11s, the metal particles 22 capable of inducing localized plasmons are brought close to each other at a high density and the dielectric substrate. 11 can be immobilized. Furthermore, in the microstructure 1 of the present embodiment, localized plasmons are effectively generated on both surfaces of the filled metal body 21 in the micropores 12 and the metal particles 22 fixed to the substrate surface 11s. Interaction can also be expected.

  Therefore, in the microstructure 1 of the present embodiment, the above effects are combined, and a higher electric field enhancing effect than that of the conventional microstructure can be obtained. The fine structure 1 of the present embodiment can be preferably used as a Raman spectroscopic device or the like that utilizes the electric field enhancement effect by localized plasmons. All the microstructures 1 of the present embodiment can be manufactured by a simple manufacturing process by batch processing.

(Design change example)
In the above embodiment, the alumina layer obtained by anodizing a part of the anodized metal body 10 is the dielectric base material 11, and the non-anodized portion is the conductor 13. The method of depositing metal in the holes 12 by electroplating to form the metal body 21 has been described. However, after all the anodized metal bodies 10 are anodized, a conductor 13 is formed by vapor deposition or the like. Also good. In this case, the material of the conductor 13 is not limited, and may be any metal or conductive material such as ITO (indium tin oxide).

  Moreover, although the case where the conductor back surface 11r is provided with the conductor 13 has been described, as a method of filling the metal body 21 into the fine holes 12, when a method that requires an electrode such as electroplating is not used, the conductor 13 may not be provided. Alternatively, the conductor 13 may be removed after the metal body 21 is formed.

  In the above embodiment, the case where the microhole 12 is a non-through hole has been described, but the microhole 12 may be a through hole. In this case, when the conductor 13 is provided on the substrate back surface 11r, the conductor 13 and the metal body 21 are preferably separated by air or a dielectric.

  In the above embodiment, only Al is cited as the main component of the anodized metal body 10 used for the production of the dielectric substrate 11, but any metal can be used as long as it can be anodized. Other than Al, Ti, Ta, Hf, Zr, Si, In, Zn, etc. can be used. The anodized metal body 10 may contain two or more types of metals that can be anodized.

  Depending on the type of anodized metal to be used, the planar pattern of the fine holes 12 to be formed varies, but the dielectric substrate 11 having a structure in which the fine holes 12 having substantially the same shape in plan view are arranged adjacent to each other is formed. Will not change.

  Moreover, although the case where the micropores 12 are regularly arranged using anodization has been described, the method of forming the micropores 12 is not limited to anodic oxidation. The above-described embodiment using anodization is preferable because the entire surface can be collectively processed, can cope with an increase in area, and does not require an expensive apparatus, but other than using anodization, the surface of a substrate such as a resin is used. Forming a plurality of recesses regularly arranged by nanoimprint technology, drawing a plurality of recesses regularly arranged by electron drawing technology such as focused ion beam (FIB) and electron beam (EB) on the surface of a substrate such as metal, etc. These microfabrication technologies can be mentioned. The fine holes 12 may or may not be regularly arranged.

  In the above embodiment, the metal particles 22 are formed by heat treatment after forming the metal film 20 on the substrate surface 11s, but the method of forming the metal particles 22 is not limited. Forming methods other than the above embodiments include a method using a metal colloid, an LB method, a silane coupling method, an oblique deposition method, a deposition using a mask, a natural evaporation after replacing citric acid with CTAB (J. Am. Chem). Soc., Vol. 127, 14992-14993, 2005.).

"Raman spectroscopy equipment"
Next, the Raman spectroscopic apparatus according to the embodiment of the present invention will be described based on FIG. 3 by taking as an example the case where the microstructure 1 according to the above embodiment is used as a Raman spectroscopic device. FIG. 3 is a schematic configuration diagram of the Raman spectroscopic device 2 of the present embodiment.

  The Raman spectroscopic apparatus 2 according to the present embodiment includes a Raman spectroscopic device 1 including the fine structure according to the above embodiment, a light irradiation unit 30 that irradiates the Raman spectroscopic device 1 with the measurement light L having a specific wavelength, and scattered light. A spectroscopic means 40 for performing spectroscopic analysis is generally configured. The light irradiation means 30 includes a single wavelength light source 31 such as a laser and a light guide system such as a mirror 32 that guides light emitted from the light source. The light irradiation means 30 is configured to irradiate the surface 1s on the metal particle 22 side of the Raman spectroscopic device 1 with which the sample X is brought into contact with the light L having a specific wavelength.

  The spectroscopic means 40 includes a spectroscopic detector 41, a condensing lens 43 that condenses the scattered light Ls from the sample, and a guide such as a mirror 42 that guides the scattered light collected by the condensing lens 43 to the spectroscopic detector 41. It consists of an optical system, which scatters scattered light (Raman scattered light) Ls generated on the surface 1s of the Raman spectroscopic device 1 to obtain a spectrum of Raman scattered light (Raman spectrum). The spectroscopic means 40 is arranged so that the scattered light Ls generated on the surface 1 s of the Raman spectroscopic device 1 is incident thereon.

  In such a configuration, the light L having a specific wavelength irradiated from the light irradiation means 30 is scattered by the surface 1 s of the Raman spectroscopic device 1 that is in contact with the sample X, and the generated scattered light Ls is incident on the spectral means 40. The scattered light Ls is split by the spectroscopic means 40, and a Raman spectrum is generated. Since the Raman spectrum varies depending on the type of the sample X to be measured, the substance can be identified.

  For example, if a known antibody is immobilized on the surface 1s of the Raman spectroscopic device 1 and measurement is performed, if the antigen is contained in the sample X, the binding between the two occurs and the resulting Raman spectrum changes. Identification can be performed. If a known antigen is immobilized on the surface 1s of the Raman spectroscopic device 1, antibody identification can be performed in the same manner.

  In the Raman spectroscopic apparatus 2 of the present embodiment, the measurement can be performed by attaching the Raman spectroscopic device 1 to a sample cell in which the sample X can be filled.

  Since the Raman spectroscopic apparatus 2 of the present embodiment is configured using the Raman spectroscopic device 1 (fine structure 1) of the above embodiment, the Raman scattering is effectively enhanced and the data reliability is high. Highly sensitive Raman spectroscopic measurement can be performed. In particular, in the device 1 for Raman spectroscopy, when the micropores 12 are arranged substantially regularly, an electric field enhancement effect with high in-plane uniformity can be obtained, so that Raman spectroscopy measurement with higher data reliability can be performed. It is possible to implement.

  Further, in the Raman spectroscopic device 2 of the present embodiment, it is preferable that the spectroscopic unit 40 receives only the scattered light of the non-specular reflection component of the measurement light L on the surface 1 s of the Raman spectroscopic device 1 and separates it. . Since the specular reflection component has a light intensity that is too high and weak Raman scattered light that is originally desired to be detected may not be detected satisfactorily, such a configuration enables highly accurate analysis.

  The microstructure of the present invention can be preferably used as a sensor device or a Raman spectroscopic device used for a biosensor or the like.

(A) is a whole perspective view which shows the structure of the microstructure of one Embodiment based on this invention, (b) is thickness direction sectional drawing. (A)-(e) is a figure which shows the manufacturing method of the microstructure of FIG. The figure which shows the structure of the Raman spectroscopy apparatus of one Embodiment which concerns on this invention.

Explanation of symbols

1 Fine structure (Device for Raman spectroscopy)
1s surface 10 anodized metal body 11 dielectric substrate (metal oxide layer)
11s substrate surface 12 micropores 13 conductor (non-anodized portion)
20 Metal film 21 Metal body 22 Metal particle 2 Raman spectroscopic device 30 Light irradiation means 40 Spectroscopic means r Minimum height difference d Particle diameter L Light (measurement light)
Ls scattered light (Raman scattered light)
X sample

Claims (12)

In a microstructure having a plurality of micropores inside and having a dielectric base material in which the plurality of micropores are opened at least on the surface of the base material, wherein the base material surface is irradiated with light,
At least a part of the plurality of micropores is filled with a metal body having a size capable of inducing localized plasmon by the light irradiation, and the non-openings of the plurality of micropores on the surface of the base material are filled. A fine structure in which a plurality of metal particles having a size capable of inducing localized plasmons by light irradiation are fixed to a portion.   The fine structure according to claim 1, wherein an average particle diameter of the plurality of metal particles is less than a wavelength of the light.   The fine structure according to claim 1 or 2, wherein an average diameter of the plurality of micropores is less than a wavelength of the light.   The minimum height difference between the surface of the base material and the surface of the metal body filled in the plurality of micropores is equal to or less than an average particle diameter of the plurality of metal particles. 4. The fine structure according to any one of 3 above.   The dielectric substrate is made of a metal oxide body obtained by anodizing at least a part of a metal body to be anodized, and the plurality of micropores are formed in the metal oxide body in the process of the anodization. The microstructure according to any one of claims 1 to 4, wherein the microstructure is a structure.   The metal particles are formed by forming a metal film of the same component as the metal particles on the surface of the base material, and then aggregating the constituent metals of the metal film into particles by heat treatment. The fine structure according to any one of claims 1 to 5, wherein:   The microstructure according to claim 6, wherein a temperature of the heat treatment is not lower than a melting point of the metal film and lower than a melting point of the dielectric substrate. In a Raman spectroscopic device in which a sample is brought into contact with a surface, measurement light is incident on the sample, and Raman scattered light of the measurement light is detected.
A Raman spectroscopic device comprising the fine structure according to claim 1. The Raman spectroscopic device according to claim 8,
Light irradiation means for irradiating the surface of the Raman spectroscopic device with the measurement light;
A Raman spectroscopic apparatus comprising: spectroscopic means for spectrally scattering scattered light generated on the surface to obtain a spectrum of Raman scattered light. A step (A) of preparing a dielectric substrate having a plurality of micropores therein and having at least a plurality of micropores open on the surface of the substrate;
A step (B) of forming a metal film on non-opening portions of the plurality of micropores on the surface of the substrate;
Filling at least a part of the plurality of micropores with a metal body having a size capable of inducing localized plasmons;
A plurality of metal particles having a size capable of inducing localized plasmons in non-opening portions of the plurality of micropores on the surface of the base material by aggregating the constituent metals of the metal film by a heat treatment to form particles. And a step (D) of forming a microstructure.   11. The method for manufacturing a microstructure according to claim 10, wherein in the step (D), the temperature of the heat treatment is set to be equal to or higher than a melting point of the metal film and lower than a melting point of the dielectric base material. In the step (C), when the step (B) is carried out, the step (C-1) of partially filling the metal having the same component as the metal film into the plurality of micropores,
The step of further filling the plurality of fine holes with the same or different metal as filled in step (C-1) to increase the amount of filled metal in the plurality of fine holes (C-2) 12. The method for producing a fine structure according to claim 10 or 11, characterized by comprising:

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