JP2007238988A - Method for producing fine structure body, and fine structure body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for safely producing a fine structure having regularly arrayed pores in a short period of production time without using a compound of highly toxic hexavalent chromic acid, and to provide the fine structure produced with the method. <P>SOLUTION: The method for producing the fine structure body having micropores on its surface comprises the steps of: preparing an aluminum member comprising an aluminum substrate and an anodic oxide film having micropores existing on the surface of the aluminum substrate; and subjecting the aluminum member to a film dissolution treatment of dissolving a part the anodic oxide film with the use of a solution having a viscosity of 0.05 to 100.0 Pa s at 25°C at 1 atmospheric pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a microstructure and a manufacturing method thereof.

  In the technical fields of metal and semiconductor thin films, thin wires, dots, etc., the phenomenon of electrical, optical and chemical peculiarities can be seen by confining the movement of free electrons in a size smaller than a certain characteristic length. It has been known. Such a phenomenon is called “quantum mechanical size effect (quantum size effect)”. Research and development of functional materials applying such a unique phenomenon is being actively conducted. Specifically, a material having a structure finer than several hundred nm is referred to as a “microstructure” or “nanostructure”, and is one of the objects of material development.

  As a method for manufacturing such a fine structure, for example, a method for directly manufacturing a nano structure by a semiconductor processing technique including a fine pattern forming technique such as photolithography, electron beam exposure, and X-ray exposure can be given.

In particular, much research has been conducted on a method for manufacturing a microstructure having a regular microstructure.
For example, as a method for forming a regular structure in a self-regulating manner, an anodized alumina film (anodized film) obtained by subjecting aluminum to an anodizing treatment in an electrolytic solution can be mentioned. It is known that a plurality of fine pores (micropores) having a diameter of about several nm to several hundred nm are regularly formed in the anodized film. By using this self-ordering of the anodized film and obtaining a perfectly regular arrangement, theoretically, hexagonal prism cells with a regular hexagonal bottom centered around the micropores are formed, and adjacent micropores are formed. It is known that the connecting line forms an equilateral triangle.

As examples of applications of such an anodized film having micropores, optical functional nanodevices, magnetic devices, luminescent carriers, catalyst carriers and the like are known. For example, Patent Document 1 describes that a pore is sealed with a metal to generate localized plasmon resonance and applied to an apparatus for Raman spectroscopic analysis.
Prior to the anodic oxidation treatment for forming such micropores, a method is known in which a depression that is a starting point for generating micropores in the anodic oxidation treatment is formed. By forming such depressions, it becomes easy to control the micropore array (hereinafter also referred to as “pore array”) and the pore diameter variation within a desired range.
As a general method for forming the depression, a self-ordering method using the self-ordering property of the anodized film is known. This is a method for improving the regularity by utilizing the property that the micropores of the anodized film are regularly arranged and removing the factors that disturb the regular arrangement.
In this self-ordering method, as described in Patent Document 1, after anodizing once, an immersion treatment in a mixed aqueous solution of phosphoric acid and hexavalent chromic acid is performed, and then the anodizing treatment is performed again in order. However, there has been a demand for a manufacturing method with a shorter manufacturing process time and higher safety.

JP 2005-307341 A

  Therefore, the present invention provides a microstructure capable of obtaining a microstructure having a short manufacturing process time, safety, and high pore regularity without using a highly toxic hexavalent chromic compound. An object is to provide a manufacturing method and a microstructure obtained by the method.

  As a result of intensive research to achieve the above object, the present inventor has found that the viscosity at 25 ° C. and 1 atm is used instead of dissolving the anodized film again using a mixed aqueous solution of phosphoric acid and hexavalent chromic acid, and performing anodization again. By using a solution having a 0.10 to 100.0 Pa · s to dissolve a part of the oxide film layer, the manufacturing process time is short, and the pores are regularly arranged with high regularity. The present inventors have found that a structure can be obtained and completed the present invention.

That is, the present invention provides the following (i) to (iv).
(I) An aluminum member having an aluminum substrate and an anodized film having micropores present on the surface of the aluminum substrate, at least,
Using a solution having a viscosity of 0.05 to 100.0 Pa · s at 25 ° C. and 1 atm, a fine structure having a micropore on the surface by performing a film dissolution treatment for dissolving a part of the anodized film A method for producing a fine structure.
(Ii) The method for producing a microstructure according to (i), wherein the aluminum member is obtained by subjecting the surface of the aluminum substrate to an anodizing treatment for forming an anodized film of 10 to 2000 g / m ^2. .
(Iii) A microstructure obtained by the method for producing a microstructure described in (i) or (ii) above.
(Iv) The microstructure according to (iii) above, wherein the degree of ordering defined by the following formula (1) for the micropore is 50% or more.
Ordering degree (%) = B / A × 100 (1)
In the above formula (1), A represents the total number of micropores in the measurement range. B is centered on the center of gravity of one micropore, and when a circle with the shortest radius inscribed in the edge of another micropore is drawn, the center of gravity of the micropore other than the one micropore is set inside the circle. This represents the number in the measurement range of the one micropore to be included.

  According to the method for producing a fine structure of the present invention, a fine structure having a short production process time, safety, and high pore arrangement regularity can be obtained without using a highly toxic hexavalent chromic compound. be able to.

The present invention is described in detail below.
The manufacturing method of the microstructure of the present invention is as follows:
At least an aluminum member having an aluminum substrate and an anodized film having micropores present on the surface of the aluminum substrate,
Using a solution having a viscosity of 0.05 to 100.0 Pa · s at 25 ° C. and 1 atm, a fine structure having a micropore on the surface by performing a film dissolution treatment for dissolving a part of the anodized film Is a method of manufacturing a fine structure.

[Aluminum member]
The aluminum member used in the production method of the present invention has an aluminum substrate and an anodized film having micropores present on the surface of the aluminum substrate.
In the present invention, such an aluminum member can be obtained by subjecting at least one surface of an aluminum substrate to an anodic oxidation process described later.
In the present invention, such an aluminum member is preferably obtained by subjecting the surface of an aluminum substrate to an anodizing treatment for forming an anodized film of 10 to 2000 g / m ² , as will be described later. more preferably obtained by performing anodizing treatment to form an anodized film of 50 to 1500 g / m ^2, further that obtained by performing anodizing treatment to form an anodized film of 100 to 1000 g / m ² preferable. When the film mass of the anodized film is within this range, it is easy to dissolve a part of the anodized film in the film dissolution treatment described later.

FIG. 1 is a schematic end view of an aluminum member and a microstructure for explaining the method for manufacturing a microstructure according to the present invention.
As shown in FIG. 1A, the aluminum member 10a has an aluminum substrate 12a and an anodized film 14a having micropores 16a existing on the surface of the aluminum substrate 12a.

<Aluminum substrate>
The aluminum substrate is not particularly limited, and specific examples thereof include a pure aluminum plate; an alloy plate containing aluminum as a main component and containing a small amount of foreign elements; high-purity aluminum is deposited on low-purity aluminum (for example, recycled material). Examples include a substrate obtained by coating a surface of silicon wafer, quartz, glass or the like with a method such as vapor deposition or sputtering; a resin substrate obtained by laminating aluminum; and the like.

  In the present invention, the surface of the aluminum substrate on which the anodized film is provided by an anodic oxidation treatment described later preferably has an aluminum purity of 99.5% by mass or more, more preferably 99.9% by mass or more. Preferably, it is 99.99 mass% or more. When the aluminum purity is in the above range, the regularity of the pore arrangement is sufficient.

  In the present invention, the surface of the aluminum substrate on which the anodized film is provided by an anodic oxidation process to be described later is preferably preliminarily degreased and mirror-finished, and particularly obtained by the production method of the present invention. In the case of using the use of the fact that the fine structure is light-transmitting, it is preferable to perform heat treatment in advance from the viewpoint of widening the region having a high regularity of the pore arrangement.

(Heat treatment)
The heat treatment is preferably performed at 200 to 350 ° C. for about 30 seconds to 2 minutes. Specifically, for example, a method of placing an aluminum substrate in a heating oven can be used.
By performing such heat treatment, a region having a high regularity of pore arrangement generated by an anodic oxidation process described later is widened.
Moreover, it is preferable to cool the aluminum substrate after heat treatment rapidly. As a method of cooling, for example, a method of directly feeding into water or the like can be mentioned.

(Degreasing treatment)
The degreasing treatment uses acid, alkali, organic solvent, etc. to dissolve and remove the organic components such as dust, fat, and resin adhered to the surface of the aluminum substrate, and in each treatment described later due to the organic components. This is done for the purpose of preventing the occurrence of defects.

Specifically, as the degreasing treatment, for example, a method in which an organic solvent such as various alcohols (for example, methanol), various ketones (for example, methyl ethyl ketone), benzine, volatile oil or the like is brought into contact with the aluminum substrate surface at room temperature (organic Solvent method); a method of bringing a liquid containing a surfactant such as soap or neutral detergent into contact with the aluminum substrate surface at a temperature from room temperature to 80 ° C., and then washing with water (surfactant method); concentration of 10 to 200 g A method in which an aqueous solution of sulfuric acid / L is brought into contact with an aluminum substrate surface for 30 to 80 seconds at a temperature from room temperature to 70 ° C. and then washed with water; an aqueous sodium hydroxide solution having a concentration of 5 to 20 g / L is applied to the aluminum substrate surface at room temperature. while contacting about seconds, the aluminum substrate surface and the electrolyte by passing a direct current of a current density of 1 to 10 a / dm ² in the cathode, the , A method of neutralizing by bringing a nitric acid aqueous solution having a concentration of 100 to 500 g / L into contact; while bringing various known anodizing electrolytes into contact with the aluminum substrate surface at room temperature, the aluminum substrate surface is used as a cathode and a current density of 1 to A method in which a 10 A / dm ² direct current is applied or an alternating current is applied for electrolysis; an alkaline aqueous solution having a concentration of 10 to 200 g / L is brought into contact with the aluminum substrate surface at 40 to 50 ° C. for 15 to 60 seconds; A method of neutralizing by bringing a nitric acid aqueous solution having a concentration of 100 to 500 g / L into contact; an emulsion obtained by mixing light oil, kerosene, etc. with a surfactant, water, etc. is brought into contact with the aluminum substrate surface at a temperature from room temperature to 50 ° C. Then, a method of washing with water (emulsification and degreasing method); a mixed solution of sodium carbonate, phosphates, surfactant and the like on the surface of the aluminum substrate at a temperature from room temperature to 50 ° C. Contacting 0-180 seconds, then, a method of washing with water (phosphate method); and the like.

  Among these, the organic solvent method, the surfactant method, the emulsion degreasing method, and the phosphate method are preferable from the viewpoint that the fat content on the aluminum surface can be removed while the aluminum hardly dissolves.

  Moreover, a conventionally well-known degreasing agent can be used for a degreasing process. Specifically, for example, various commercially available degreasing agents can be used by a predetermined method.

(Mirror finish processing)
The mirror finishing process is performed in order to eliminate unevenness on the surface of the aluminum substrate, for example, rolling streaks generated during the rolling of the aluminum substrate, and improve the uniformity and reproducibility of the sealing process by an electrodeposition method or the like.
In the present invention, the mirror finish is not particularly limited, and a conventionally known method can be used. Examples thereof include mechanical polishing, chemical polishing, and electrolytic polishing.

  Examples of the mechanical polishing include a method of polishing with various commercially available polishing cloths, a method of combining various commercially available abrasives (for example, diamond, alumina) and a buff. Specifically, when an abrasive is used, a method in which the abrasive used is changed from coarse particles to fine particles over time is preferably exemplified. In this case, the final polishing agent is preferably # 1500. Thereby, the glossiness can be 50% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 50% or more).

As chemical polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. Examples thereof include various methods described in 164 to 165.
Further, the phosphoric acid-nitric acid method, the Alupol I method, the Alupol V method, the Alcoa R5 method, the H ₃ PO ₄ —CH ₃ COOH—Cu method, and the H ₃ PO ₄ —HNO ₃ —CH ₃ COOH method are preferably exemplified. . Among these, the phosphoric acid-nitric acid method, the H ₃ PO ₄ —CH ₃ COOH—Cu method, and the H ₃ PO ₄ —HNO ₃ —CH ₃ COOH method are preferable.
By chemical polishing, the glossiness can be made 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

As electrolytic polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. 164-165; various methods described in US Pat. No. 2,708,655; “Practical Surface Technology”, vol. 33, no. 3, 1986, p. The method described in 32-38;
By electropolishing, the gloss can be 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

  These methods can be used in appropriate combination. Specifically, for example, a method of performing mechanical polishing in which the abrasive is changed from coarse particles to fine particles with time, and then performing electrolytic polishing is preferable.

By mirror finishing, for example, a surface having an average surface roughness R _{a of} 0.1 μm or less and a glossiness of 50% or more can be obtained. The average surface roughness _Ra is preferably 0.03 μm or less, and more preferably 0.02 μm or less. Further, the glossiness is preferably 70% or more, and more preferably 80% or more.
The glossiness is a regular reflectance obtained in accordance with JIS Z8741-1997 “Method 3 60 ° Specular Gloss” in the direction perpendicular to the rolling direction. Specifically, using a variable angle gloss meter (for example, VG-1D, manufactured by Nippon Denshoku Industries Co., Ltd.), when the regular reflectance is 70% or less, the incident reflection angle is 60 degrees and the regular reflectance is 70%. In the case of exceeding, the incident / reflection angle is 20 degrees.

<Anodizing treatment>
The anodizing treatment is a treatment for forming an anodized film on the surface of the aluminum substrate.
As the anodizing treatment, a conventionally known method can be used. Specifically, it is preferable to use the self-ordering method described later.

The self-ordering method is a method of improving the regularity by utilizing the property that the micropores of the anodized film are regularly arranged and removing the factors that disturb the regular arrangement. Specifically, high-purity aluminum is used, and an anodized film is formed at a low speed over a long period of time (for example, several hours to several tens of hours) at a voltage according to the type of the electrolytic solution.
In this method, since the pore diameter depends on the voltage, a desired pore diameter can be obtained to some extent by controlling the voltage.

The average flow rate of the electrolytic solution in the anodizing treatment is preferably 0.5 to 20.0 m / min, more preferably 1.0 to 15.0 m / min, and 2.0 to 10.0 m / min. More preferably, it is min. By performing anodizing treatment at a flow rate in the above range, uniform and high regularity can be obtained.
Moreover, the method of flowing the electrolytic solution under the above-mentioned conditions is not particularly limited, but, for example, a method using a general stirring device such as a stirrer is used. In particular, it is preferable to use a stirrer that can control the stirring speed by digital display because the average flow velocity can be controlled. Examples of such a stirring apparatus include “Magnetic Stirrer HS-50D (manufactured by AS ONE)” and the like.

  For the anodizing treatment, for example, a method in which an aluminum substrate is used as an anode in a solution having an acid concentration of 1 to 10% by mass can be used. The solution used for the anodizing treatment is preferably an acid solution, more preferably sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid, etc., among which sulfuric acid, phosphoric acid, Oxalic acid is particularly preferred. These acids can be used alone or in combination of two or more.

The conditions for anodizing treatment vary depending on the electrolyte used, and therefore cannot be determined unconditionally. In general, however, the electrolyte concentration is 0.1 to 20% by mass, the solution temperature is -10 to 30 ° C., and the current density. 0.01 to 20 A / dm ² , voltage 3 to 300 V, electrolysis time 0.5 to 30 hours are preferable, electrolyte concentration 0.5 to 15% by mass, liquid temperature −5 to 25 ° C., current density 0 0.05 to 15 A / dm ² , voltage 5 to 250 V, electrolysis time 1 to 25 hours are more preferable, electrolyte concentration 1 to 10% by mass, solution temperature 0 to 20 ° C., current density 0.1 to 10 A / More preferably, dm ² , voltage of 10 to 200 V, and electrolysis time of 2 to 20 hours are used.
The thickness of the anodized film is preferably 1 to 300 μm, more preferably 5 to 150 μm, and still more preferably 10 to 100 μm.

  The treatment time for the anodizing treatment is preferably 0.5 minutes to 16 hours, more preferably 1 minute to 12 hours, and further preferably 2 minutes to 8 hours.

  The anodizing treatment can be performed by changing the voltage intermittently or continuously in addition to being performed under a constant voltage. In this case, it is preferable to decrease the voltage sequentially. This makes it possible to reduce the resistance of the anodized film.

  In the present invention, when the anodic oxide film is formed at a low temperature, the arrangement of micropores becomes regular and the pore diameter becomes uniform.

Moreover, in this invention, it is preferable that the film | membrane mass (film thickness) of the anodic oxide film formed by such an anodic oxidation process is 10-2000 g / m < ² > (3-600 micrometers), and 50-1500 g / m ² (15 to 450 μm) is more preferable, and 100 to 1000 g / m ² (30 to 300 μm) is even more preferable. When the film mass (film thickness) of the anodized film is within this range, as described above, it is easy to dissolve a part of the anodized film in the film dissolution treatment described later.
The average pore density of the micropores is preferably 50-1500 / μm ² .
Further, the area ratio occupied by the micropores is preferably 20 to 50%.
The area ratio occupied by the micropore is a ratio of the total area of the opening of the micropore to the area of the aluminum surface. In the calculation of the area ratio occupied by the micropores, the micropores include those that are not filled with metal and those that are not filled with metal. Specifically, it is obtained by measuring the surface porosity before the sealing treatment.

[Film dissolution treatment]
The film dissolution treatment in the production method of the present invention is a part of the anodized film formed on the surface of the aluminum substrate using a solution having a viscosity of 0.05 to 100.0 Pa · s at 25 ° C. under 1 atm. In this way, a fine structure having micropores on the surface can be obtained.

In the present invention, the solution for dissolving a part of the anodized film is an acid aqueous solution or an alkaline aqueous solution, and has a viscosity of 0.05 to 100.0 Pa · s at 25 ° C. under 1 atm. 0.0 Pa · s is preferable, and 1.0 to 50.0 Pa · s is more preferable.
When the viscosity of the solution is within this range, it is possible to obtain a microstructure having a short manufacturing process time, safety, and high pore arrangement regularity without using a highly toxic hexavalent chromic compound. . This is because the solution has a high viscosity, so that the solution does not easily penetrate into the inside of the micropore, particularly the bottom portion close to the aluminum substrate, and the dissolution of the anodized film from the inside of the micropore is suppressed and the anodization is performed. It is considered that the vicinity of the surface of the film, that is, the portion with low regularity of the pore arrangement can be efficiently removed, and the fine structure can be obtained without performing the above-described film removal treatment of the anodic oxide film. It is done.

  Specifically, as shown in FIG. 1 (B), the surface of the anodic oxide film 14a dissolves while suppressing dissolution of the inside of the micropores 16a shown in FIG. The aluminum member 10b having the anodized film 14b having the micropores 16b on the aluminum substrate 12a is obtained.

In the present invention, the dissolution of a part of the anodized film in the film dissolution treatment is preferably performed by immersing the aluminum member in the solution.
Here, the part is preferably 0.01 to 99.99% by mass of the anodized film, more preferably 0.1 to 75.00% by mass, and 1.0 to 60.00%. More preferably, it is mass%.
Moreover, it is preferable that immersion time is 1-1000 minutes, It is more preferable that it is 10-750 minutes, It is still more preferable that it is 15-500 minutes.

In the present invention, when an acid aqueous solution is used as the solution, specifically, as the acid aqueous solution, for example, an aqueous solution of sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid or the like can be used, and these are used alone. Or two or more of them may be used in combination.
Moreover, it is preferable that the density | concentration of acid aqueous solution is 1-10 mass%, and it is preferable that the temperature of acid aqueous solution is 25-40 degreeC.

On the other hand, when an alkaline aqueous solution is used as the solution, specifically, as the alkaline aqueous solution, for example, an aqueous solution of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like can be used, and these are used alone. Or two or more of them may be used in combination.
Moreover, it is preferable that the density | concentration of aqueous alkali solution is 0.1-5 mass%, and it is preferable that the temperature of aqueous alkali solution is 20-35 degreeC.
More specifically, for example, 50 g / L, 40 ° C. phosphoric acid aqueous solution, 0.5 g / L, 30 ° C. sodium hydroxide aqueous solution, 0.5 g / L, 30 ° C. potassium hydroxide aqueous solution and the like are preferable. Used.

In the present invention, these acid or alkali aqueous solutions can be mixed with various polymers, monomers and the like in order to adjust to a desired viscosity. Especially, it is preferable to mix a polymer from a viewpoint of raising a viscosity.
As such a polymer, it is preferable to use, for example, a water-soluble polymer that is soluble in an acid or alkaline aqueous solution. Specifically, a polymer containing many polar groups (for example, ionic groups, hydroxyl groups, amino groups, amide groups, ether groups, etc.) having a strong interaction with water can be mentioned. More specifically, natural polymers such as starches, casein, glue, gelatin, gum arabic, sodium alginate and pectin; semi-synthetic polymers such as carboxymethyl cellulose, methyl cellulose and viscose; polyvinyl alcohol, polyacrylamide, polyethyleneimine, poly Synthetic polymers such as sodium acrylate, polyethylene oxide, polyvinyl pyrrolidone, and the like. These may be used alone or in combination of two or more.

[Microstructure]
The fine structure of the present invention is obtained by the above-described method for producing a fine structure of the present invention.
In addition, as described in the description of the aluminum member, the fine structure of the present invention preferably has an average pore density of 50 to 1500 / μm ² , and the area ratio occupied by the micropores is 20 to 50%. Is preferred.
Furthermore, the microstructure of the present invention preferably has a degree of ordering defined by the following formula (1) for the micropores of 50% or more.

  Ordering degree (%) = B / A × 100 (1)

  In the above formula (1), A represents the total number of micropores in the measurement range. B is centered on the center of gravity of one micropore, and when a circle with the shortest radius inscribed in the edge of another micropore is drawn, the center of gravity of the micropore other than the one micropore is set inside the circle. This represents the number in the measurement range of the one micropore to be included.

FIG. 2 is an explanatory diagram of a method for calculating the degree of ordering of pores. The above formula (1) will be described more specifically with reference to FIG.
The micropore 1 shown in FIG. 2 (A) draws a circle 3 (inscribed in the micropore 2) having the shortest radius that is centered on the center of gravity of the micropore 1 and inscribed in the edge of another micropore. In this case, the center of the circle 3 includes six centroids of micropores other than the micropore 1. Therefore, the micropore 1 is included in B.
The micropore 4 shown in FIG. 2 (B) draws a circle 6 (inscribed in the micropore 5) having the shortest radius that is centered on the center of gravity of the micropore 4 and inscribed in the edge of another micropore. In this case, the center of gravity of the micropores other than the micropores 4 is included inside the circle 6. Therefore, the micropore 4 is not included in B. In addition, the micropore 7 shown in FIG. 4B is centered on the center of gravity of the micropore 7 and has the shortest radius 9 inscribed in the edge of another micropore (inscribed in the micropore 8). Is drawn, the circle 9 includes seven centroids of micropores other than the micropore 7. Therefore, the micropore 7 is not included in B.

<Pore wide processing>
The fine structure of the present invention can be subjected to pore wide processing depending on the application.
The pore-wide treatment is a treatment for expanding the pore diameter of the micropore by dissolving the anodized film by immersing the aluminum member in an acid aqueous solution or an alkali aqueous solution after the anodizing treatment.
This makes it easy to control the regularity of the arrangement of micropores and the variation in pore diameter. Further, by dissolving the barrier film at the bottom of the micropores of the anodized film, it is possible to selectively deposit the inside of the micropores and to slightly increase the pore diameter variation.
The viscosity of the solution used for the film dissolution treatment at 25 ° C. under 1 atm is 0.05 to 100.0 Pa · s, whereas the acid aqueous solution or the alkali aqueous solution used for pore wide treatment at 25 ° C. under 1 atm. The viscosity at is about 0.001 Pa · s.

When an aqueous acid solution is used for the pore wide treatment, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or a mixture thereof.
Moreover, it is preferable that the density | concentration of acid aqueous solution is 1-10 mass%, and it is preferable that the temperature of acid aqueous solution is 25-40 degreeC.

On the other hand, when an alkaline aqueous solution is used for pore wide treatment, it is preferable to use an aqueous solution of at least one alkali selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide.
Moreover, it is preferable that the density | concentration of aqueous alkali solution is 0.1-5 mass%, and it is preferable that the temperature of aqueous alkali solution is 20-35 degreeC.
Specifically, for example, 50 g / L, 40 ° C. phosphoric acid aqueous solution, 0.5 g / L, 30 ° C. sodium hydroxide aqueous solution, 0.5 g / L, 30 ° C. potassium hydroxide aqueous solution, etc. are preferably used. It is done.

  The immersion time in the acid aqueous solution or alkaline aqueous solution is preferably 8 to 60 minutes, more preferably 10 to 50 minutes, and further preferably 15 to 30 minutes.

<Other processing>
The microstructure of the present invention can be subjected to other treatments as necessary.
For example, when the fine structure obtained by the production method of the present invention is used as a sample stage and it is desired to suspend the aqueous solution into a film, it may be subjected to a hydrophilization treatment in order to reduce the contact angle with water. Good. The hydrophilic treatment can be performed by a conventionally known method.

  In addition, when the microstructure obtained by the production method of the present invention is used as a sample stage and targeted for a protein that is denatured with acid or decomposed, it is used for anodizing treatment and remains on the aluminum surface. In order to neutralize the acid that is being neutralized, a neutralization treatment may be performed. The neutralization treatment can be performed by a conventionally known method.

Furthermore, the microstructure of the present invention can also remove the aluminum substrate depending on the application.
The method for removing the aluminum substrate is not particularly limited, but for example, a method in which alumina is hardly soluble or insoluble, and is immersed in a solvent in which aluminum is soluble is preferable.
Specific examples of the solvent include halogen solvents such as bromine and iodine; acidic solvents such as dilute sulfuric acid, phosphoric acid, oxalic acid, sulfamic acid, benzenesulfonic acid, and amidosulfonic acid; sodium hydroxide and potassium hydroxide. Preferred examples include alkaline solvents such as calcium hydroxide; Of these, bromine and iodine are preferable.

The microstructure of the present invention can also carry a catalyst on the micropores of the anodized film depending on the application.
In the present invention, the catalyst is not particularly limited as long as it has a catalytic function, but specific examples thereof include AlCl ₃ , AlBr ₃ , Al ₂ O ₃ , SiO ₂ , SiO ₂ -Al ₂ O ₃ , Si Zeolite, SiO ₂ —NiO, activated carbon, PbO / Al ₂ O ₃ , LaCoO ₃ , H ₃ PO ₄ , H ₄ P ₂ O ₇ , Bi ₂ O ₃ —MoO ₃ , Sb ₂ O ₅ , SbO ₅ —Fe ₂ O ₃ , SnO ₂ —Sb ₂ O ₅ , Cu, CuO ₂ —Cr ₂ O ₃ , Cu—Cr ₂ O ₃ —ZnO, Cu / SiO ₂ , CuCl ₂ , Ag / α-Al ₂ O ₃ , Au, ZnO, ZnO—Cr ₂ O ₃ , ZnCl ₂ , ZnO—Al ₂ O ₃ —CaO, TiO ₂ , TiCl ₄ .Al (C ₂ H ₅ ) ₃ , Pt / TiO ₂ , V ₂ O ₅ , V ₂ O ₅ —P ₂ O ₅ , V ₂ O ₅ / TiO ₂ , Cr ₂ O ₃ , Cr ₂ O ₃ / Al ₂ O ₃ , M _{oO 3, MoO 3 -SnO 2,} Co · Mo / Al 2 O 3, Ni · Mo / Al 2 O 3, MoS 2, Mo-Bi-O, MoO 3 -Fe 2 O 3, H 3 PMo 12 O 40 _{, WO 3, H 3 PW 12} O 40, MnO 2, Fe-K 2 O-Al 2 O 3, Fe 2 O 3 -Cr 2 O 3, Fe 2 O 3 -Cr 2 O 3 -K 2 O, Fe ₂ O ₃ , Co, Co / activated carbon, Co ₃ O ₄ , Co carbonyl complex, Ni, RaneyNi, Ni / support, modified Ni, Pt, Pt / Al ₂ O ₃ , Pt—Rh—Pd / support, Pd, Pd _{/ SiO 2, Pd / Al 2} O 3, PdCl 2 -CuCl 2, Re, Re-Pt / Al 2 O 3, Re 2 O 7 / Al 2 O 3, Ru, Ru / Al 2 O 3, Rh, Rh A complex etc. are mentioned.

The method for supporting the catalyst is not particularly limited, and a conventionally known method can be used.
For example, an electrodeposition method; a method in which a dispersion of catalyst particles is applied to an aluminum member having an anodized film and dried; The catalyst is preferably a single particle or an aggregate.

A conventionally known method can be used as the electrodeposition method. Specifically, for example, in the case of gold electrodeposition, an aluminum member is immersed in a dispersion at 30 ° C. containing 1 g / L HAuCl ₄ and 7 g / L H ₂ SO _4, and a constant voltage of 11 V ( (Adjusted with slidac), and a method of electrodeposition treatment for 5 to 6 minutes.
As the electrodeposition method, Hyundai Kagaku, January 1997, p. Examples using copper, tin and nickel are described in detail in 51-54, and this method can also be used.

The dispersion used in the method using catalyst particles can be obtained by a conventionally known method. For example, it can be obtained by a method for producing fine particles by a low vacuum evaporation method or a method for producing a catalyst colloid in which an aqueous solution of catalyst salt is reduced.
The catalyst colloidal particles preferably have an average particle size of 1 to 200 nm, more preferably 1 to 100 nm, and even more preferably 2 to 80 nm.
As the dispersion medium used in the dispersion, water is preferably used. In addition, solvents that can be mixed with water, for example, alcohols such as ethyl alcohol, n-propyl alcohol, i-propyl alcohol, 1-butyl alcohol, 2-butyl alcohol, t-butyl alcohol, methyl cellosolve, and butyl cellosolve A mixed solvent with water can also be used.

  In the method using the catalyst colloidal particles, the coating method is not particularly limited, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

As the dispersion liquid used in the method using the catalyst colloid particles, for example, a gold colloid particle dispersion liquid and a silver colloid particle dispersion liquid are preferably used.
As the dispersion of colloidal gold particles, for example, those described in JP-A-2001-89140 and JP-A-11-80647 can be used. Commercial products can also be used.
The dispersion of silver colloidal particles preferably contains silver and palladium alloy particles in that they are not affected by the acid eluted from the anodized film. In this case, the palladium content is preferably 5 to 30% by mass.

  After applying the dispersion, it is appropriately washed with a solvent such as water. As a result, only the catalyst particles supported on the micropores remain in the anodic oxide film, and the catalyst particles not filled in the micropores are removed.

Adhesion amount of the catalyst after carrying treatment is preferably from 10 to 1000 mg / m ^2, more preferably from 50 to 800 mg / m ^2, particularly preferably from 100 to 500 mg / m ^2.
Further, the surface porosity after the supporting treatment is preferably 70% or less, more preferably 50% or less, and particularly preferably 30% or less. The surface porosity after the supporting treatment is a ratio of the total area of the openings of the unsupported micropores to the area of the aluminum surface.

  The catalyst colloidal particles used in the dispersion usually have a variation in particle size distribution of about 10 to 20% as a coefficient of variation. In the present invention, by setting the pore diameter variation within a specific range, colloidal particles having a variation in particle size distribution can be efficiently used for sealing.

  When the pore diameter is 50 nm or more, a method using catalyst colloidal particles is preferably used. Moreover, when a pore diameter is less than 50 nm, an electrodeposition method is used suitably. A method of combining both is also preferably used.

  Since the microstructure of the present invention has micropores having a regular arrangement, it can be applied to various uses.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.
1. Fabrication of microstructure (Examples 1-18, Comparative Examples 1 and 2)
As shown in Table 1, each fine structure was obtained by subjecting the substrate to a mirror finish treatment, an anodizing treatment, a film dissolution treatment, a re-anodizing treatment and a pore-wide treatment in that order. In Table 1, “-” indicates that the corresponding processing is not performed.

  Hereinafter, the substrate and each process will be described.

(1) Substrate The substrates used for the production of the fine structure are as follows. These were cut and used so that they could be anodized in an area of 10 cm square.
-Substrate 1: High-purity aluminum, manufactured by Wako Pure Chemical Industries, Ltd., purity 99.99 mass%, thickness 0.4 mm
-Substrate 2: Aluminum JIS A1050 material provided with surface layer A, manufactured by Nippon Light Metal Co., Ltd., purity 99.5% by mass, thickness 0.24 mm
-Substrate 3: Aluminum JIS A1050 material provided with surface layer B, manufactured by Nippon Light Metal Co., Ltd., purity 99.5% by mass, thickness 0.24 mm
-Substrate 4: Aluminum JIS A1050 material, manufactured by Nippon Light Metal Co., Ltd., purity 99.5% by mass, thickness 0.30 mm
-Substrate 5: Aluminum JIS A1050 material provided with a surface layer C, manufactured by Nippon Light Metal Co., Ltd., purity 99.5% by mass, thickness 0.30 mm
-Substrate 6: Aluminum JIS A1050 material provided with a surface layer D, manufactured by Nippon Light Metal Co., Ltd., purity 99.5% by mass, thickness 0.30 mm

-Substrate 7: Aluminum vapor deposition film, Trefan AT80, manufactured by Toray Industries, Inc., purity 99.9% by mass, thickness 0.02 mm
-Substrate 8: Aluminum XL untreated material provided with surface layer A, manufactured by Sumitomo Light Metal Industries, Ltd., purity 99.3 mass%, thickness 0.30 mm
-Substrate 9: Glass provided with surface layer E, manufactured by AS ONE, purity 99.9% by mass, thickness 5 mm
-Substrate 10: Silicon wafer provided with surface layer E, manufactured by Shin-Etsu Chemical Co., Ltd., purity 99.99% by mass or more-Substrate 11: Synthetic quartz provided with surface layer E, VIOSIL-SG-2B, manufactured by Shin-Etsu Chemical Co., Ltd. Purity 99.99% by mass or more, thickness 0.6mm
-Substrate 12: A copper-clad laminate (RAS33S42, manufactured by Shin-Etsu Chemical Co., Ltd., purity unknown, thickness 0.08 mm) provided with a surface layer E provided with an Al-Cu alloy film by sputtering.

The aluminum JIS A1050 material has a regular reflectance of 40% in the vertical direction (standard deviation of 10%), a regular reflectance of 15% in the lateral direction (standard deviation of 10%), and a purity of 99.5% by mass (standard deviation of 0.1%). 1% by mass).
Further, the above-mentioned aluminum XL non-treated material has a vertical regular reflectance of 85% (standard deviation of 5%), a horizontal regular reflectance of 83% (standard deviation of 5%), and a purity of 99.3% by mass (standard deviation of 0). .1% by mass).

The surface layers A to E were provided as follows.
Surface layer A is a vacuum deposition method under the conditions of ultimate pressure: 4 × 10 ⁻⁶ Pa, deposition current: 40 A, substrate: 150 ° C. heating, deposition material: aluminum wire with purity of 99.9% by mass (manufactured by Niraco) Was formed on the substrate. The thickness of the surface layer A was 0.2 μm.
The surface layer B was formed by the same method as the surface layer A, except that an aluminum wire (manufactured by Niraco) having a purity of 99.99% by mass was used as the vapor deposition material. The thickness of the surface layer B was 0.2 μm.
Surface layer C has ultimate pressure: 4 × 10 ⁻⁶ Pa, sputtering pressure: 10 ⁻² Pa, argon flow rate: 20 sccm, substrate: 150 ° C. control (with cooling), bias: none, sputtering power source: RC, sputtering power: It was formed on the substrate by sputtering under the conditions of RF400W, sputtering material: 3N backing plate (manufactured by Kyodo International Co., Ltd.) having a purity of 99.9% by mass. The thickness of the surface layer C was 0.5 μm.
The surface layer D was formed by the same method as the surface layer C except that a 4N backing plate (manufactured by Kyodo International Co., Ltd.) having a purity of 99.99% by mass was used as the sputtering material. The thickness of the surface layer D was 0.5 μm.
The surface layer E was formed by the same method as the surface layer A except that the thickness was 1 μm.

The thickness of the surface layer is determined by masking the PET substrate, performing the vacuum deposition method and the sputtering method while changing the time under the same conditions as described above, and using an atomic force microscope (AFM). It adjusted by adjusting time using the correlation calibration curve of the time and film thickness obtained by measuring each film thickness.
In addition, the purity of the surface layer was determined using a scanning X-ray photoelectron spectrometer (Quantum 2000, manufactured by ULVAC-PHI) to perform a full quantitative analysis while digging in the depth direction with an ion gun for etching. The content of was quantified by a calibration curve method. As a result, all the surface layers had substantially the same purity as the vapor deposition material or the sputtering material.

(2) Mirror surface finishing process About the board | substrates 1-6 among the said substrates 1-12, the following mirror surface finishing processes were performed.
<Mirror finish processing>
By performing polishing using a polishing cloth, buffing and electrolytic polishing in this order, a mirror finish was applied. After buffing, it was washed with water.
Polishing using a polishing cloth uses a polishing disk (Struers Abramin, manufactured by Marumoto Kogyo Co., Ltd.) and a water-resistant polishing cloth (commercially available), and the number of the water-resistant polishing cloth is # 200, # 500, # 800, # 1000 and # The change was made in the order of 1500.
The buffing was performed using a slurry-like abrasive (FM No. 3 (average particle size 1 μm) and FM No. 4 (average particle size 0.3 μm), both manufactured by Fujimi Incorporated).
The electrolytic polishing was performed for 2 minutes using an electrolytic solution (temperature: 70 ° C.) having the following composition, using the anode as a substrate and the cathode as a carbon electrode at a constant current of 130 mA / cm ² . As a power source, GP0110-30R (manufactured by Takasago Seisakusho) was used.

<Electrolyte composition>
-660 mL of 85% by mass phosphoric acid (reagent manufactured by Wako Pure Chemical Industries, Ltd.)
・ Pure water 160mL
・ Sulfuric acid 150mL
・ Ethylene glycol 30mL

(3) Anodizing treatment Anodizing treatment was performed on the surfaces of the substrates 1 to 6 subjected to the mirror finishing treatment and the surfaces of the substrates 7 to 12 not subjected to the mirror finishing treatment under the conditions shown in Table 1.
The contents of the anodizing conditions shown in Table 1 are specifically shown in Table 2. That is, the substrate is immersed in the electrolytic solution, and the anodizing treatment is performed at the electrolytic solution type, concentration, average flow rate and temperature, voltage, current density and processing time shown in Table 2 and shown in Table 2. An anodized film having a coating amount and a film thickness was formed. In the anodizing treatment, NeoCool BD36 (manufactured by Yamato Kagaku Co., Ltd.) was used as a cooling device, Pear Stirrer PS-100 (manufactured by EYELA) as a stirring and heating device, and GP0650-2R (manufactured by Takasago Seisakusho) as a power source. Further, the average flow rate of the electrolyte was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE).
The amount and film thickness of the anodized film were measured by the following method and shown in Table 2.
The coating amount was calculated from the difference (decrease amount) in mass before and after immersion after being immersed in a treatment solution (50 ° C.) having the following composition after anodizing treatment under each condition for 12 hours.
On the other hand, the film thickness was measured using an eddy current film thickness meter (EDY-1000, manufactured by Sanko Electronics Laboratory Co., Ltd.).
<Composition of treatment solution>
・ Pure water 1500g
・ 85% phosphoric acid 100g
・ Chronic anhydride 30g

  In Table 2, reagents manufactured by Kanto Chemical Co., Inc. were used for phosphoric acid, oxalic acid and sulfuric acid. The current density showed a stable value.

(4) Film dissolution treatment Film dissolution treatment was performed on the surfaces of the substrates 1 to 12 subjected to anodization treatment under the conditions shown in Table 1.
The contents of the film dissolution treatment conditions shown in Table 1 are specifically shown in Table 3. That is, an aluminum member having an anodized film is immersed in the treatment liquid having the composition and temperature shown in Table 3 for the time shown in Table 3, and the amount of dissolution shown in Table 3 (the amount of the anodized film before dissolution). % By mass with respect to the coating amount) was dissolved.
The viscosity of the treatment liquid was measured using an Ubbelohde viscometer tube at 25 ° C. and 1 atmosphere.

  In Table 3, as for 85 mass% phosphoric acid, chromic anhydride, and other polymers, reagents manufactured by Kanto Chemical Co., Inc. were used.

(5) Re-anodizing treatment For Comparative Example 1 in which all of the anodized film was removed by the film dissolution treatment, re-anodizing treatment was performed under the conditions shown in Table 1 after the film dissolution treatment.
The contents of the reanodizing treatment conditions shown in Table 1 are specifically shown in Table 4. That is, the aluminum member after the film dissolution treatment is immersed in the electrolytic solution, and the electrolytic treatment is performed a plurality of times with the kind, concentration and temperature of the electrolytic solution shown in Table 4, the first voltage and the number of times. It was. When the electrolytic treatment is performed a plurality of times, the electrolysis is interrupted when the initial value V ₀ of the constant voltage is reached first, and the electrolysis is interrupted when the initial value 0.9 × V ₀ of the constant voltage is reached the second time. In the third time, the electrolysis is interrupted when the constant voltage initial setting value 0.8 × V ₀ is reached. In the nth time, the constant voltage initial setting value {1-0.1 × (n−1) )} is repeated a plurality of times to suspend the electrolysis when it reaches the × V _0.
The thickness of the anodized film was measured by the same method as above, and the increment was shown in Table 4.

(6) Pore-wide treatment After the film dissolution treatment (after re-anodizing treatment for Comparative Example 1, the same applies in the following paragraph), the pore-wide treatment was performed under the conditions shown in Table 1.
The contents of the pore wide processing conditions shown in Table 1 are specifically shown in Table 5. That is, the aluminum member after the film dissolution treatment was immersed in the treatment liquid of the type, concentration and temperature shown in Table 5 for the time shown in Table 5.

2. Properties of the fine structure A surface photograph (magnification 20000 times) of the fine structure obtained above was taken by FE-SEM, and the ordering defined by the above formula (1) for the micropore in a 100 nm × 100 nm field of view. The degree was measured. The degree of ordering was measured at 10 locations, and the average value was calculated. The results are shown in Table 1.

3. Total processing time etc. The total processing time of each fine structure obtained above was measured. The results are shown in Table 6 with and without the use of hexavalent chromic acid compounds. In Table 6, the case where the hexavalent chromic acid compound was not used was indicated as “◯”, and the case where it was used was indicated as “x”.

  As is apparent from Table 6, the manufacturing method of the fine structure of the present invention (Examples 1 to 18) does not use a highly toxic hexavalent chromic compound, and the manufacturing process time is short, and the fine structure can be safely formed. In addition, a fine structure having a high regularity of pore arrangement can be obtained to the same extent as when a hexavalent chromic acid compound is used (Comparative Example 2).

It is a typical end view of an aluminum member and a microstructure for explaining a manufacturing method of a microstructure of the present invention. It is explanatory drawing of the method of calculating the regularization degree of a pore.

Explanation of symbols

1, 2, 4, 5, 7, 8, 16a, 16b Micropore 3, 6, 9 Circle 10a, 10b Aluminum member 12a Aluminum substrate 14a, 14b Anodized film 20 Fine structure

Claims (4)

An aluminum member having an aluminum substrate and an anodized film having micropores present on the surface of the aluminum substrate, at least,
Using a solution having a viscosity of 0.05 to 100.0 Pa · s at 25 ° C. and 1 atm, a fine structure having a micropore on the surface by performing a film dissolution treatment for dissolving a part of the anodized film A method for producing a fine structure. It said aluminum member, on the surface of the aluminum substrate, obtained by performing anodizing treatment to form an anodized film of 10 to 2000 g / m ^2, method for manufacturing a microstructure according to claim 1.   A fine structure obtained by the method for producing a fine structure according to claim 1. The microstructure according to claim 3, wherein the degree of ordering defined by the following formula (1) for the micropore is 50% or more.
Ordering degree (%) = B / A × 100 (1)
In the formula (1), A represents the total number of micropores in the measurement range. B is centered on the center of gravity of one micropore, and when a circle with the shortest radius inscribed in the edge of another micropore is drawn, the center of gravity of the micropore other than the one micropore is placed inside the circle. This represents the number in the measurement range of the one micropore to be included.

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