JP2001213700A - Nanostructure and method for manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a nanostructure in which anodized alumina is formed in a region on a substrate in units of alumina cells. SOLUTION: In a nanostructure comprising anodized alumina 9 formed in a region on a base 8, the anodized alumina 9 has a structure in which an alumina cell 5 having pores 3 is a unit structure. A nanostructure formed in a region on the substrate in units of alumina cells 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nanostructure and a method for manufacturing the same, and more particularly, to a nanostructure and a functional material such as electronic devices, optical devices, and microdevices, and structural materials that can be used in a wide range. It relates to the manufacturing method.

[0002]

2. Description of the Related Art Metal and semiconductor thin films, fine lines, dots, and the like are required to have a size smaller than a certain characteristic length.
When the movement of electrons is confined, it may exhibit unique electrical, optical, and chemical properties. From such a viewpoint, there is a growing interest in materials (nanostructures) having a structure finer than several 100 nm as functional materials.

[0003] As a method for producing such a nanostructure,
For example, photolithography, electron beam exposure,
There is a method of directly manufacturing a nanostructure by a semiconductor processing technology such as a fine pattern forming technology such as X-ray exposure.

[0004] In addition to such a fabrication method, an attempt has been made to realize a novel nanostructure based on a regular structure formed naturally, that is, a structure formed self-regularly. is there. Many studies have begun on these techniques because there is a possibility that a finer and special structure can be produced more than conventional methods depending on a microstructure used as a base.

[0005] An example of such a self-regular method is anodic oxidation, which can easily produce a nanostructure having nanosize pores in a controlled manner. For example, anodized alumina produced by anodizing aluminum and its alloys in an acidic bath is known.

When anodizing an Al plate in an acidic electrolyte,
A porous oxide film (anodized alumina) is formed (for example, RC Furneaux, WR Rigby)
& A. P. Davids "NATURE", Vol.
337, P147 (1989), etc.). This porous oxide film has a specific geometrical structure in which alumina cells are assembled and arranged using a columnar alumina cell as a unit structure. The center of each alumina cell has a diameter of several nm to several hundred n.
m having extremely fine cylindrical pores (nano holes).
The distance between the pores corresponds to the cell size, which is the diameter of the alumina cell, and ranges from several nm to several hundred nm. These columnar pores have a high aspect ratio and are excellent in uniformity of cross-sectional diameter. The diameter and spacing of the pores are controlled to some extent by adjusting the current and voltage during anodic oxidation, and the thickness of the oxide film and the depth of the pores are controlled by controlling the anodic oxidation time. Is possible.

Also, the verticality of the pores of anodized alumina,
In order to improve linearity and independence, a method of performing two-stage anodic oxidation, that is, once removing the porous oxide film formed by performing anodic oxidation, performing anodic oxidation again to obtain better verticality, A method for producing anodized alumina (ordered nanoholes) having pores exhibiting linearity and independence has been proposed (“Jpn. Journal of Japan”).
Applied Physics ", Vol. 35,
Part 2, No. IB, pp. L126-L129,
15 January 1996). Here, this method uses that the depression on the surface of the aluminum plate formed when removing the anodic oxide film formed by the first anodic oxidation becomes the starting point of the pores for the second anodic oxidation.

In addition, a method of forming a pore starting point by press patterning, that is, a depression formed by pressing a substrate having a plurality of projections on the surface of an aluminum plate as a pore starting point is formed. A method of producing a porous oxide film having pores exhibiting better control of the shape, spacing and pattern by performing anodic oxidation later has also been proposed (JP-A-10-112292).

Various applications have been attempted, focusing on the specific geometric structure of the anodized alumina. The explanation by Masuda is detailed, but the application examples are listed below. For example, there is an application as a film utilizing the wear resistance and insulation resistance of the anodic oxide film, and an application to a filter by peeling the film. Furthermore, by using a technique of filling a nanohole with a metal or a semiconductor or a replica technique of the nanohole, coloring, a magnetic recording medium, an EL light emitting element, an electrochromic element, an optical element, a solar cell, a gas sensor, etc. Various applications have been attempted. Moreover,
It is expected to be applied to various fields such as quantum effect devices such as quantum wires and MIM elements, and molecular sensors using nanoholes as a chemical reaction field. (Masuda "Solid Physics" 31,
493 (1996))

[0010]

The direct fabrication of nanostructures by the above-described semiconductor processing technology has problems such as poor yield and high equipment cost, and is easily produced with good reproducibility by a simple method. A technique that can do this is desired. From this point of view, the self-regular method, particularly the anodic oxidation method, can easily produce nanostructures with good control, and can produce large-area nanostructures. Is desired. In particular, the anodized alumina, in which the pore arrangement of anodized alumina is created by a technique using two-step anodization or press patterning, has a structure in which pores are regularly arranged, and has a perpendicularity of pores, linearity of pores. It is preferable because it has excellent properties and alignment.

Further, considering the use of anodized alumina as a device, it is necessary to perform patterning. As a technique for this, resist patterning and etching are performed by lithography technology, but it is not easy to form and position a nanometer-sized pattern. In particular, since anodized alumina has a periodic structure having an alumina cell as a unit structure, it is preferable to align the pattern boundary with the end face of the alumina cell, but it has been difficult to highly align the pattern in this way. .

Such a problem can be solved by controlling the presence or absence of an alumina cell for each alumina cell. However, such a technique has not been known. Such an area forming technique using an alumina cell as a unit enables production of a single alumina cell structure or anodized alumina in which the number of alumina cells (the number of pores) is controlled. If the presence or absence of an alumina cell can be formed on a substrate in units of an alumina cell, further application development can be expected in electronic devices and optical devices.

An object of the present invention is to solve these problems. That is, an object of the present invention is to disclose a nanostructure in which anodized alumina is highly formed in a region at a cell size level, and to disclose a technique of forming anodized alumina in units of alumina cells on a substrate. It is to be.

It is another object of the present invention to disclose a novel nanostructure and nanostructure device based on anodized alumina having a region formed thereon, so that nanoholes can be used as functional materials in various directions.

[0015]

The above objects can be attained by the following constitution and manufacturing method of the present invention. That is, in a nanostructure having a porous body made of alumina formed in a region on a substrate, the porous body made of alumina formed in the region has a structure in which an alumina cell having pores is a unit structure. And a region formed on the substrate by using the alumina cell as a unit.

In a nanostructure having anodized alumina formed in a region on a substrate, the anodized alumina formed in a region has a structure in which an alumina cell having pores is formed as a unit structure. A nanostructure characterized by being formed in a region on the substrate in units of cells.

Preferred embodiments of the above nanostructure are shown below. In particular, a nanostructure characterized in that the end face of the anodized alumina formed in the region coincides with the end face of the alumina cell. Preferably, the nanostructure is characterized in that the existence region or non-existence region of the anodized alumina can be designated by two-dimensional lattice coordinates using the alumina cell as a unit lattice. The region where the anodized alumina is present or absent is determined by using the alumina cell as a unit cell.
Nanostructures characterized in that they can be specified by dimensional hexagonal lattice coordinates are preferred.

A nanostructure characterized by comprising anodized alumina formed on the substrate in the form of isolated alumina cells is preferred. A nanostructure characterized by comprising anodized alumina formed in a region consisting of alumina cells arranged in a row on the substrate. Nanostructures characterized by having a filler in the pores are preferred. A nanostructure characterized by comprising an electrode at the bottom of the alumina cell that is electrically connected to the filling in the pores is preferred.

Furthermore, a light emitting device comprising a filler in pores of the nanostructure, wherein the filler has a light emitting function, wherein the filler has a dielectric constant different from that of the porous body An optical device, characterized in that the filler is a magnetic material.

The present invention also relates to a method for producing a nanostructure comprising anodically oxidized alumina regionally formed on a substrate, wherein at least two or more types of pores are formed at a site mainly composed of aluminum on the substrate. A first step of forming points, a second step of anodizing the aluminum-based site to form anodized alumina, and a part of the anodized alumina depending on the type of the pore starting point. And a third step of forming a region by eliminating the above.

Among them, particularly, the pore starting point has a concave shape as compared with the surroundings, and the first step of forming the pore starting point is at least two or more types of pores having different concave shapes. A method for producing a nanostructure, comprising a step of forming a starting point.

The first step of forming the pore starting point is a step of forming at least two or more kinds of pore starting points having different depths of the concave shape. Is the way.

The present invention also relates to a method for producing a nanostructure comprising anodically oxidized alumina formed in a region on a substrate, wherein at least two or more types of pores are formed at a site mainly composed of aluminum on the substrate. Forming a region having a different point arrangement, a second step of forming an anodized alumina by anodizing the main part of the aluminum, and forming anodized alumina according to the region having a different pore starting point arrangement. And a third step of forming a region by eliminating a part of the nanostructure.

Among them, the first step includes at least two steps.
A step of forming regions having different types of pore start point intervals, and the third step is a step of partially eliminating anodized alumina in accordance with the regions having different pore start point intervals. A method for producing a nanostructure characterized by the following.

Further, in the above-mentioned method for producing a nanostructure, the pore starting point is produced by irradiating with a Shuto ion beam.
Further, there is provided a nanostructure produced by the above-mentioned manufacturing method.

According to the present invention, it is possible to provide a nanostructure comprising anodized alumina in which the presence or absence of an alumina cell is formed as a region on the substrate in units of the alumina cell. In particular, it is possible to provide a structure in which the end face 63 of the region coincides with the end face of the alumina cell as shown in FIG. In particular, a pattern excellent in the perpendicularity of the end face 63 can be manufactured even for thick anodized alumina.

Furthermore, a structure in which the area with or without the alumina cell can be designated by two-dimensional lattice coordinates using the alumina cell as a unit structure can be employed. In addition, FIG.
A structure such as a single alumina cell as shown in FIG. 1A or an alumina cell arranged in a line as shown in FIG.

As described above, the anodized alumina highly formed on the substrate is composed of quantum wires, MIM devices, molecular sensors, coloring, magnetic recording media, EL light emitting devices, electrochromic devices, photonic crystal devices, and electronic devices. Emission elements, solar cells, gas sensors, wear-resistant, insulation-resistant coatings,
It can be applied in various forms including filters, and has the effect of significantly expanding its application range.

In particular, a material having a periodic structure having a different permittivity at a length of about the wavelength of light becomes a photonic crystal,
There is a possibility that the material will be capable of advanced light control. In effect, however, a photonic band gap appears in which light is prohibited in a certain wavelength range. Anodized alumina formed in a high area on a substrate utilizes a periodic structure of anodization, and may be used as a photonic crystal. The technique of forming a region according to the present invention enables control of a photonic crystal structure and a photonic band structure,
Further, a waveguide and a defect can be formed. In particular,
In a photonic crystal, when a defect is introduced, a localized state of light can be obtained. Therefore, it is known that a localized state of light is obtained by patterning an alumina cell. The application to an optical recording medium or the like can be considered by utilizing these characteristics. In addition, if a light-emitting substance is present in the photonic crystal and the wavelength of light emission due to spontaneous emission from the excited state falls within the photonic band, spontaneous emission is not possible and the life of the excited state can be extended, so the anodized alumina of the present invention By filling the pores with a luminous body, a light emitting element with a low threshold, a light emitting element with a narrow emission spectrum width, a low threshold laser, and the like can be expected.

In addition, when a magnetic material is filled in the pores of anodized alumina, magnetic nanowires can be obtained. Filling a magnetic material into anodized alumina patterned in units of alumina cells can be expected to be applied to magnetic devices such as magnetic field sensors, magnetoresistive elements, and magnetic recording media.

The method for producing a nanostructure according to the present invention has an effect that a nanostructure can be produced with a high degree of control. The nanostructure of the present invention is created by forming a pore starting point at a desired position on the workpiece and then anodizing the workpiece.When forming the pore starting point, respectively. By controlling the arrangement, shape or composition of the pore starting points of the above, the presence or absence of alumina cells corresponding to each pore starting point can be independently controlled for each alumina cell by the post-anodization treatment. . According to this technique, anodized alumina in which alumina cells and pores are arranged and formed only at desired positions on the substrate can be realized.

Further, in the present invention, the area formation in units of alumina cells can be performed without the necessity of applying a resist or forming a pattern by a lithography technique. In particular, in order to form a latent image by patterning the presence or absence of alumina cells directly at the stage of forming the pore starting point before anodic oxidation, the alumina cells and patterns required for lithography are used.
No alignment is required.

Further, when the lithography technique is used, the pattern region becomes as shown in FIG. 11 (b), and it is difficult to match the boundary of the alumina cell with the pattern boundary. Since patterning is performed in units of cells, a structure in which the pattern boundary coincides with the end face of the alumina cell as shown in FIG. 11A can be easily manufactured. In particular, a pattern excellent in the perpendicularity of the end face can be produced even for thick anodized alumina. Furthermore, by setting the position of the start point in a two-dimensional lattice shape, it is possible to have a structure in which the presence / absence area of the alumina cell can be designated by two-dimensional lattice coordinates using the alumina cell as a unit structure.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The nanostructure of the present invention is a nanostructure comprising anodized alumina formed regionally on a substrate, wherein the anodized alumina has a structure in which an alumina cell having pores is a unit structure, It is characterized in that a region is formed on the substrate in units of cells.

Further, the method for producing a nanostructure of the present invention comprises:
A method for producing a nanostructure comprising anodically oxidized alumina regionally formed on a substrate, the method comprising the steps of: forming a pore starting point at a site mainly composed of aluminum on a substrate; A step of forming an anodized alumina by anodizing a portion mainly containing the aluminum and a third step of forming a region by causing a part of the anodized alumina to disappear. Further, the first step is a step of forming at least two or more kinds of pore starting points, and the third step is to form a part of anodized alumina according to the kind of the pore starting points. It is characterized by the step of eliminating.

The method for producing a nano-other structure according to the present invention relates to a method for producing a nano-structure having anodized alumina formed in a region on a substrate. A first step of forming a pore starting point in a portion mainly containing aluminum, anodizing the portion mainly containing aluminum, a second step of forming anodized alumina, A third step of forming a region by eliminating a part thereof, and further, the first step is a step of forming at least two or more types of regions having different pore starting point sequences, The third step is characterized in that a part of the anodized alumina is eliminated in accordance with the regions having different pore starting point arrangements.

<Structure of Nanostructure> FIGS. 1 and 2 show an example of the structure of the nanostructure of the present invention. In FIG. 1, 9
Represents anodized alumina, 5 represents an alumina cell, 3 represents pores (nanoholes), and 8 represents a substrate.

The nanostructure of the present invention has anodized alumina 9 formed by anodizing aluminum or an aluminum alloy on the base 8, and the presence or absence of the anodized alumina is determined by the unit structure of the alumina cell 5. It is characterized by being formed as a region.

As shown in FIG. 2D, the anodized alumina 9 has a structure in which the alumina cells 5 are assembled and arranged using a columnar alumina cell as a unit structure. At the center of each alumina cell, there are columnar pores 3 (nano holes), and the pores 3 can be arranged substantially parallel to each other and at equal intervals. The pore spacing is the cell size of the alumina cell 2
R, at intervals of several nm to 500 nm, and pores 3
Has a diameter of 2 nm to 500 nm (see FIG. 4B). The thickness of the anodized alumina is the height of the alumina cell, and the depth (length) of the pores 3 can be controlled by the anodic oxidation time, the thickness of Al, etc., for example, 10 nm to 100 μm. Between. In the figure, the alumina cells are drawn as hexagonal columns, and the pores are drawn as cylinders.However, depending on the arrangement of the alumina cells and the arrangement of the pore starting points, the present invention is not limited to this. It can take any shape. These columnar pores have a high aspect ratio and are also excellent in the uniformity of the diameter of the cross section.

In the present invention, as the region formation, for example, as shown in FIG. In addition, for example, FIG.
An isolated alumina cell as shown in FIG. 1C or a structure in which alumina cells are arranged in a line as shown in FIG. Further, depending on the manufacturing conditions, the end face 63 of the anodized alumina region can be made to coincide with the end face of the alumina cell as shown in FIG.

The arrangement of the alumina cells 5 and the pores 3 can be such that the alumina cells are arranged in a two-dimensional lattice as shown in FIG. FIG. 4A shows a square lattice arrangement, and FIG. 4B shows a hexagonal lattice arrangement, but other arbitrary lattice arrangements are also possible. Further, in such an arrangement,
By forming regions of anodized alumina using the alumina cell as a unit structure, the arrow shown in FIG.
An area can be formed so that the presence or absence of an alumina cell can be specified by specifying the dimensional lattice coordinates. For example, FIG.
(A) is an example in which the existence region and the non-existence region of anodized alumina can be designated by two-dimensional hexagonal lattice coordinates using an alumina cell as a unit structure.

Further, it is possible to embed a functional material such as a metal and a semiconductor in the pores of such a nanostructure.

<Method for Producing Nanostructure> The method for producing a nanostructure of the present invention comprises a first step of forming a pore starting point at a site mainly composed of aluminum on a substrate; A second step of forming an anodized alumina having pores formed at pore starting points by anodizing a portion to be formed, and a third step of forming a region by eliminating a part of the anodized alumina Having.

In particular, by forming two or more kinds of pore starting points in the first step, a part of the anodized alumina can be eliminated in the third step according to the kind of the pore starting point. Can be.

In addition, in the first step, two or more types of regions having different arrangements of pore starting points are formed, and in the third step, anodized alumina is formed in accordance with the type of pore starting point arrangement. Can be partially eliminated.

Hereinafter, a method for manufacturing a nanostructure of the present invention will be described with reference to FIG. The description will be made in the order of (a) to (e) of FIG. The following steps (a) to (e) correspond to FIG.
(A) to (e).

(A) Workpiece preparation Workpiece 7 is prepared. The workpiece of the present invention has a portion mainly composed of aluminum.

As an example of the first embodiment of the workpiece of the present invention, there is a bulk containing Al as a main component, such as an aluminum plate or an aluminum wire. In addition, as shown in FIG.
An example in which a film 12 containing Al as a main component is formed on a base 13 is also used. At this time, examples of the substrate include substrates such as an insulating substrate such as quartz glass, a semiconductor substrate such as silicon and gallium abrasive, and a substrate having one or more layers formed on these substrates. . For example, if a substrate in which a conductive film such as Ti, Nb, or Cu is formed on a substrate is used, the uniformity of the depth of the pores can be improved. In addition, as a method of forming a film containing Al as a main component, any film formation method including resistance heating evaporation, EB evaporation, sputtering, CVD, and plating can be applied.

(B) Step of Forming Pore Start Point In this step, a pore start point 2 is formed at a desired position in a portion of the workpiece mainly containing Al.

The starting point of the pore is different from the surroundings in physical or chemical properties such as shape, composition and crystallinity. As a method for forming the pore starting point, a focused ion beam (FI
B), a method using SFM (scanning probe microscope) such as AFM (atomic force microscope), and a depression using press patterning disclosed in Japanese Patent Application Laid-Open No. 10-112292. And a method of forming a dent by etching after forming a resist pattern.

Further, in the present invention, in this step, the pores are formed by controlling the arrangement, shape or composition of the pore starting points. By controlling the pore starting point, it becomes possible to control the arrangement, interval, position, and the like of the alumina cells and the pores, and further, to control the formation of regions.

According to the present invention, for forming a region, specifically,
Two or more types of pore starting points or regions having different pore starting point arrangements are formed. Eventually, it becomes possible to form an anodic oxidized alumina cell as an area by using the alumina cell as a unit structure in accordance with the kind and arrangement of the pore starting points.

For example, as shown in FIG. 7 (a), by forming two kinds of pore starting points, it is possible to form an alumina cell region as shown in FIG. 7 (a '). 8 to 1
8 to 10 (b '), (c'), and (d ') by the arrangement of the starting points such as 0 (b), (c), and (d), respectively.
Can be formed.

By controlling the position and arrangement of the pore starting points, the arrangement of the alumina cells 5 and the pores 3 can be controlled. For example, as shown in FIG. 4, the alumina cells may be arranged in a two-dimensional lattice. FIG. 4A shows a square lattice arrangement, and FIG. 4B shows a hexagonal lattice arrangement, but other arbitrary lattice arrangements are also possible. In this case, the pore starting points are similarly formed in a two-dimensional lattice.
By applying the regular starting point arrangement and the anodic oxidation conditions adapted thereto, a regular two-dimensional arrangement of alumina cells can be realized. In such a case, the patterning of the presence / absence of the alumina cell also follows this start point array, so that the patterning of the alumina cell can be designated by the coordinates of a two-dimensional array. That is, in the nanostructure fabricated in this manner, the region where anodized alumina exists and the region where it does not exist can be designated by two-dimensional lattice coordinates using an alumina cell as a unit structure.

In particular, since the arrangement of the alumina cells and the pores tends to be arranged in a hexagonal lattice pattern due to self-organization during anodic oxidation, it is preferable to previously form the pore starting points in a hexagonal lattice form. At this time, since there is a correlation between the voltage of the anodic oxidation and the interval between the pores, it is preferable to set the pore starting point in consideration of this interval.

In the case of manufacturing as described above, FIG.
As shown in (a), the region where anodized alumina exists and the region where it does not exist can be designated by two-dimensional hexagonal lattice coordinates using an alumina cell as a unit structure. As shown in FIG. 11A, the end face 63 of the region where the anodized alumina exists may coincide with the end face of the alumina cell, or alternatively, the end face may coincide with the center of the alumina cell.

In order to produce the above two or more different pore starting points, in the method using a focused ion beam, irradiation of the focused ion beam such as the irradiation amount of the focused ion beam, the beam diameter, and the ion irradiation energy is performed. By controlling the conditions, it is possible to control the concave shape and the composition of the pore starting point. In the technique using press patterning, the depth and area of the concave shape at the starting point of the pore can be controlled by previously setting the shape of press patterning to a desired shape. In the method using SPM,
By controlling the force of pressing the short hand against aluminum or changing the shape of the short hand, the concave shape at the pore starting point, for example, the depth and size can be controlled. Other,
A method of locally oxidizing the aluminum surface by applying a voltage to the short hand can also be applied. In this case, the voltage,
The shape and composition of the pore starting point can be controlled by time and the like.

Among them, the method using focused ion beam irradiation does not require complicated steps such as resist coating, electron beam exposure, and resist removal, and can form the pore starting point in a short time. Since it is possible and it is not necessary to apply pressure to the workpiece, it is particularly preferable from the viewpoint of being applicable to a workpiece having low mechanical strength.

The formation of the pore starting point using the focused ion beam will be further described below. Ga, S, which is a liquid metal ion source, is used as the ion species of the focused ion beam.
i, Ge, Cs, Nb, Cu, etc., and O, N, H, He, Ar, etc., which are field ionization gas ion sources, can be used. The ionic species is not particularly limited. The beam diameter of the focused ion beam is in the range of about 5 to 100 nm.

For forming the pore starting point using a focused ion beam, a method of irradiating a workpiece with a focused ion beam in a dot shape as shown in FIG. in this way,
After the focused ion beam is made to stay at a certain dot position 31, the movement to the next dot position 31 to make the focused ion beam stay is repeated. In addition, FIG.
And a method of irradiating the workpiece with a focused ion beam to parallel line positions 32 having different directions. In this method, the focused ion beam is irradiated more at the intersection 33 of the line than at the periphery thereof, so that a pore starting point can be formed at the intersection 33 of the line.

The reason why the position where the focused ion beam is frequently irradiated is the pore starting point is that a state different from the surroundings is formed on the surface of the workpiece by ion implantation and / or ion etching. It is presumed that anodic oxidation proceeds. Further, as described above, the shape and composition of the pore starting point can be controlled by controlling the ion irradiation amount, ion irradiation energy, beam diameter, and the like.

(C) Step of Forming Pore As shown in FIG. 3 (c), by subjecting the workpiece to anodic oxidation, the portion mainly composed of aluminum is converted into anodized alumina.

FIG. 6 schematically shows the anodic oxidation apparatus used in this step.
Shown in In FIG. 6, 7 is a workpiece, 41 is a thermostat, 42 is a cathode of a Pt plate, 43 is an electrolytic solution, 44 is a reaction vessel,
5 is a power supply for applying an anodizing voltage, and 46 is an ammeter for measuring an anodizing current. Although not shown in the figure, a computer for automatically controlling and measuring the voltage and current is incorporated.

The workpiece 7 and the cathode 42 are arranged in an electrolytic solution maintained at a constant temperature by a constant temperature water bath, and anodic oxidation is performed by applying a voltage between the workpiece and the cathode from a power supply.

Examples of the electrolytic solution used for anodic oxidation include oxalic acid, phosphoric acid, sulfuric acid, and chromic acid solution, but are not particularly limited as long as there is no problem in forming pores by anodic oxidation. Various conditions such as anodizing voltage and temperature depending on each electrolytic solution can be appropriately set according to the nanostructure to be manufactured.

As described above, since the voltage of the anodic oxidation and the distance between the pores have a correlation, by using appropriate anodic oxidation conditions in accordance with the arrangement of the starting points of the pores, the step (b) can be performed. The pore 3 can be formed at a position reflecting the formed pore starting point 2.

Subsequently, the pore diameter of the anodic oxidized alumina can be controlled under the condition of a pore widening treatment of dipping in an acid solution after anodic oxidation. The pore diameter can be appropriately increased by a pore-wide treatment in which the nanostructure is immersed in an acid solution (for example, a phosphoric acid solution). A nanostructure having pores of a desired diameter can be obtained depending on the acid concentration, treatment time, temperature, and the like.

(D) Region forming step Further, the nanostructure produced in step (c) is
For example, by dipping in an acid solution such as phosphoric acid, FIG.
As shown in (d), the alumina cells can be selectively etched in accordance with the arrangement and type of the pore starting points. For example, the alumina cell at the deep concave portion at the pore starting point disappears, and the alumina cell remains at the shallow portion, forming a region.

As described above, by controlling the shape and composition of the pore starting point performed in the step (b), it is possible to produce a nanostructure in which the presence or absence of pores and alumina cells is formed at the cell size level. For example, as shown in FIG. 7A, by forming two types of pore starting points, it is possible to form an alumina cell region as shown in FIG. 7A. 8 to 1
8 to 10 (b '), (c'), and (d ') by the arrangement of the starting points such as 0 (b), (c), and (d), respectively.
Can be formed.

The reason why the etching rate varies depending on the shape and composition of the pore starting point is not clear, but the position and reaction rate of each pore bottom in the pore formation process are involved, and the shape and composition of the alumina cell are affected. It seems to have contributed to

Subsequently, as step (e), further electrodeposition,
The functional material can be filled in the pores by a technique such as CVD or vacuum melting. In addition, by selecting an appropriate material for the base material of anodized alumina,
Various electrical connections are possible.

For example, when aluminum is anodized partway, an insulating barrier layer is provided between the bottom of the pores and the underlying aluminum as shown in FIG. Electrical connection is made.

In addition, when Ti or Nb is used as a base and an aluminum film is anodized over the entire film thickness, FIG.
As shown in (b), there is a conductive path in the pore bottom barrier layer, and an electrical connection is made via this conductive path.

In addition, Cu, Pt, n-Si
When such a method is used, since the bottom of the fine hole penetrates as shown in FIG. 12C, direct electrical connection is made.

[0075]

EXAMPLES The present invention will be described below with reference to examples.
The following steps (a) to (d) will be described with reference to FIGS.
(D) will be described. 3A to 3D correspond to steps (a) to (d), respectively. FIG. 3 is a cross-sectional view illustrating a method for manufacturing a nanostructure according to the present invention.

Example 1 In this example, a nanostructure in which alumina cells were arranged in a hexagonal lattice was produced using a technique of forming a pore starting point by a focused ion beam (FIB).

(A) Preparation of Workpiece As shown in FIG. 3 (a), a 500 nm thick Al film 12 was further formed on a substrate 13 on which a 100 nm thick Nb film was formed on a Si substrate by electron beam evaporation. A workpiece 7 was prepared by sputtering.

(B) Step of Forming Pore Start Point As shown in FIG. 3B, a focused ion beam was irradiated in a dot shape on the aluminum surface of the workpiece to form a pore start point. As shown in FIG.
0 nm hexagonal lattice array with 2 different FIB irradiation conditions
The formation of different types of pore starting points was performed. Here, the ion species for the focused ion beam processing was Ga, the acceleration voltage was 30 kV, the ion beam diameter was 30 nm, and the ion current was 3 pA.
At this time, the type of the pore starting point was controlled by the irradiation time of the focused ion beam. To form the first pore start point and the second pore start point, the FIB irradiation time was set to 10 msec each.
c and 100 msec.

(C) Step of Forming Micropores The workpiece was subjected to anodizing treatment using the anodizing apparatus shown in FIG. 6 to form anodized alumina. 0.3 for acid electrolyte
Using a mol / l oxalic acid aqueous solution, the solution was kept at 3 ° C. in a thermostatic water bath, and the anodizing voltage was 40 V. The anodic oxidation current was monitored, and it was confirmed that aluminum was replaced by alumina over the entire film thickness due to the decrease in anodic oxidation current.

(D) Region forming step Next, the anodized alumina is partially eluted in accordance with the type of the pore starting point, as shown in FIG.
An area was formed. That is, 70% in a 5 wt% phosphoric acid solution.
By immersion for min, the alumina cell in the region where the second starting point was formed was etched. This treatment also serves as a pore widening treatment, and the pore diameter in the region of anodized alumina corresponding to the first starting point increases.

Evaluation (Structural Observation) Observation with an FE-SEM (field emission scanning electron microscope) revealed that the alumina cell corresponding to the second starting point disappeared and that only the alumina cell corresponding to the first starting point disappeared. Had remained. That is, as shown in FIG. 7A, anodized alumina regularly arranged in a hexagonal arrangement was formed in a desired pattern, reflecting the type of pore starting point. The pore spacing is 100 nm, the pore diameter is about 60 nm, and the height is 500 nm
It was.

The end face of the anodized alumina remaining corresponding to the first starting point almost coincided with the end face of the alumina cell. Before the anodization, the pore starting point was
As a result, it was found that concave pore starting points were arrayed on the surface of the aluminum film. Due to the irradiation time of the focused ion beam, the starting point of the second region was deeper in the concave shape than the starting point of the first region.

Thus, the presence or absence of an alumina cell is controlled by controlling the amount of the focused ion beam, that is, by controlling the shape of the starting point of the pore, and the anodized alumina is divided into units of the alumina cell. It can be seen that it can be formed.

Example 2 This example is an example in which hexagonally arranged anodized alumina was produced by using a press patterning technique. First, a press pattern substrate in which two types of protrusions were alternately and periodically arranged on a hexagonal lattice was prepared as follows.

Using an electron beam exposure apparatus, a resist pattern having openings of about 20 nm diameter and about 40 nm diameter was formed on a silicon substrate in a hexagonal lattice pattern at a period of 0.2 μm. The opening having a diameter of about 20 nm and the opening having a diameter of about 40 nm are shown in FIG.
The arrangement is the same as the arrangement of the first and second pore start points in (c). On this, chromium was vapor-deposited using a vapor deposition device, and chromium on the resist was removed together with the resist, thereby forming two types of chromium projections having a diameter of about 20 nm, a diameter of about 40 nm, and a height of 40 nm. Further, using this chromium as a mask, the silicon substrate is etched by a reactive dry etching method using CF ₄ gas, and the chromium is removed by oxygen plasma.
m and about 40 nm and two types of protrusions having a height of 60 nm have a thickness of 0.1 mm.
Press pattern substrates were regularly arranged at a period of 2 μm.

(A) Preparation of Workpiece A work piece was prepared by subjecting an aluminum plate having a purity of 99.99% and a thickness of 2 mm to electric field polishing in a mixed solution of perchloric acid and ethanol.

(B) Step of Forming Pore Start Point The substrate for a press pattern on which the above-mentioned projections have been formed is placed on the aluminum plate that has undergone the step (a), and 3 × 10 ⁸ Pa (3 By applying a pressure of ton / cm ² ), pore starting points were formed on the surface of the aluminum plate. The pattern of the pore start points reflects the shape of the press pattern substrate, and as shown in FIG. 9C, two kinds of pore start points are arranged and formed in a hexagonal lattice of 200 nm.

(C) Step of Forming Pore Anodization was performed in the same manner as in Example 1. However, the anodic oxidation voltage was 80V. (D) Region forming step Regions were formed by partially eluting anodized alumina in a 5 wt% phosphoric acid solution for 140 minutes.

Evaluation (Structural Observation) Observation with an FE-SEM (field emission scanning electron microscope) revealed that the alumina cell corresponding to the second starting point disappeared, as shown in FIG. The alumina cell corresponding to the first starting point was formed reflecting the pore starting point. That is, the structure was such that the rows of alumina cells were arranged at equal intervals. The pore diameter of the pore was about 140 nm.

Before the anodization, the starting point of the pore was determined by AFM.
Observation with an atomic force microscope revealed that concave pore start points were arrayed on the surface of the aluminum film. The starting point of the second area had a larger concave shape than the starting point of the first area.

As a result, the presence or absence of the alumina cell was controlled by controlling the shape of the pore starting point, and it was possible to form anodized alumina as a unit of the alumina cell. Such a structure in which the porous bodies are arranged at equal intervals,
By making the periodic structure approximately equal to the wavelength of light, optical properties can be controlled. That is, application as a photonic crystal can be expected.

Example 3 This example is an example in which anodized alumina of a single alumina cell isolated at the tip of a fine wire was prepared. (A) Preparation of Workpiece Purity 99.99%, thickness as workpiece A with 25 μm diameter
A mirror-finished surface of the thin wire was prepared by electropolishing in a mixed solution of perchloric acid and ethanol.

(B) Step of Forming Pore Start Point Using a focused ion beam processing apparatus, a focused ion beam was irradiated in a dot shape on the cross section of the end portion of the Al fine wire to form a pore start point. The arrangement of the pore start points was a hexagonal lattice array with a spacing of 300 nm, and the first pore start point and all other second pore start points including the periphery thereof were arranged as specific pore start points.

Here, the ion species of the focused ion beam processing is Ga, the acceleration voltage is 25 kV, the dwell time is 30 msec,
The ion beam diameter is 100 nm, the first pore starting point,
For the formation of the second pore starting point, an ion current of 50 pA was used as the first irradiation condition, and an ion current of 200 pA was used as the second irradiation condition.

(C) Step of forming pores The workpiece was subjected to anodizing treatment using the anodizing apparatus shown in FIG. 6 to form pores as shown in FIG. 2 (c). As the acid electrolyte, a 0.3 mol / l phosphoric acid aqueous solution was used, the solution was kept at 3 ° C. by a constant temperature water bath, the anodic oxidation voltage was set to 120 V,
5 min.

(D) Region forming step Anodized alumina was partially eluted in a 5 wt% phosphoric acid solution for 250 minutes to form a region.

Evaluation (Structural Observation) When the tip of the fine wire was observed by FE-SEM (field emission scanning electron microscope), only the alumina cell corresponding to the first pore starting point remained. Disappeared. That is, as shown in FIG. 1 (a), a single alumina cell was isolated at the tip of the aluminum fine wire. The outer diameter of the alumina cell is about 300 nm, the pore diameter is about 150 nm, and the height is 80.
It was 0 nm.

Thus, by controlling the current value of the ion beam, which is a condition for forming the pore starting point, an isolated alumina cell could be formed on the substrate by patterning. Such a single alumina cell can be used as a probe for STM or SN0M by filling the pores with a metal or dielectric.

Embodiment 4 This embodiment is an example in which anodized alumina having a square lattice array was formed by using a pore starting point forming technique by FIB.

(A) Preparation of Workpiece A workpiece was prepared by forming an Al film having a thickness of 500 nm on a quartz substrate by a resistance heating method.

(B) Step of Forming Pore Start Point The focused ion beam was scanned on the Al film to form parallel linear irradiation patterns at intervals of 75 nm. Further, subsequent to the formation of the horizontal line pattern, by irradiating in a line shape at intervals of 100 nm in directions different by 90 degrees,
A vertical line pattern was formed. The intersection of two vertical and horizontal lines arranged in a square lattice was used as the pore starting point.

Here, the ion species of the focused ion beam is G
a, The acceleration voltage was 25 kV, the ion beam diameter was 30 nm, and the ion current was 4 pA. In forming a vertical line pattern, the number of overlapping scans of the same line was controlled every 10 rows. That is, every ten rows, one scan row,
Rows of 10 scans were repeatedly formed.

(C) Step of forming pores Anodization and pore widening were performed in the same manner as in Example 1. However, a 0.3 mol / l sulfuric acid aqueous solution was used as the acid electrolyte, the solution was kept at 3 ° C. in a thermostatic water bath, and the anodic oxidation voltage was 25 V.

(D) Region forming step Anodized alumina was partially eluted in a 5 wt% phosphoric acid solution for 40 minutes to form a region.

Evaluation (Structural Observation) When the tip of the fine wire was observed by FE-SEM (field emission scanning electron microscope), only the alumina cell corresponding to the vertical line with a small number of scans remained. This allows
Anodized alumina arranged in a square array could be formed as a region in units of alumina cells.

Embodiment 5 This embodiment is an example in which regions of anodized alumina are formed by regions having different pore start point intervals.

(A) Preparation of Workpiece According to the first embodiment.

(B) Step of Forming Pore Start Point As shown in FIG. 5B, a focused ion beam was irradiated in a dot shape on the aluminum surface of the workpiece to form a pore start point. The arrangement of the pore start points was a hexagonal lattice arrangement with a spacing of 100 nm as shown in FIG. 7A, and the workpiece was irradiated with a focused ion beam in the form of dots to form the pore start points. In addition, two regions having different irradiation patterns of the focused ion beam were formed. The first region had a starting point interval of 100 nm, and the second region had a starting point interval of 80 nm. Here, the ion species for focused ion beam processing was Ga, the acceleration voltage was 30 kV, the ion beam diameter was 30 nm, the ion current was 3 pA, and the residence time was 100 msec.

(C) Step of forming pores Anodizing treatment was performed on the workpiece using the anodizing apparatus shown in FIG. 6 to form anodized alumina. 0.3m for acid electrolyte
Using an ol / l oxalic acid aqueous solution, the solution was kept at 3 ° C. in a thermostatic water bath, and the anodizing voltage was 40 V. The anodic oxidation current was monitored, and it was confirmed that the aluminum was replaced by alumina over the entire film thickness due to the decrease in the anodic oxidation current.

(D) Region forming step Next, anodized alumina is partially eluted to
An area was formed. The alumina cells in the second region were etched by immersing in a 5 wt% phosphoric acid solution for 70 minutes. This treatment also serves as a pore widening treatment, and the pore diameter in the region of anodized alumina corresponding to the first starting point increases.

Evaluation (Structural Observation) Observation with an FE-SEM (field emission scanning electron microscope) revealed that the alumina cells corresponding to the second region disappeared and only the alumina cells in the first region remained. That is, it was possible to form regions of anodized alumina regularly arranged in a hexagonal arrangement, reflecting the pattern of pore starting points. The pore spacing was 100 nm, the pore diameter was about 60 nm, and the height was 500 nm.

Further, the end face of the anodized alumina remaining corresponding to the first region coincided with the vicinity of the center of the alumina cell. This makes it possible to control the presence / absence of alumina cells by controlling the pore start point pattern (arrangement), that is, by controlling the shape of the pore start points, and to form anodized alumina as a region in units of alumina cells. I understand.

Embodiment 6 This embodiment is an example in which a nanostructure in which a magnetic material is filled in pores is manufactured. Anodized alumina in which regions were formed in the same manner as in the steps (a) to (d) of Example 1 was prepared. However, by controlling the irradiation amount at the pore starting point described in Example 1, the anodized alumina was set to a region where the number of pores was 10,000.

(E) Step of filling metal into pores Next, Ni metal electrodeposition is performed to fill the pores with the filler 6.
(See FIG. 3 (e)). Ni filling is 0.14
In an electrolytic solution consisting of mol / l NiSO ₄ and 0.5 mol / l H ₃ BO ₃ , Ni was immersed together with a Ni counter electrode and electrodeposited to deposit Ni in the nanoholes.

Evaluation Observation by FE-SEM revealed that all pores in the region were filled with Ni, and magnetic nanowires of 50 nm in thickness formed of Ni were formed. Furthermore, the anodized alumina was formed in a desired pattern, that is, in a desired number of alumina cells. The electrodeposits in each hole reached the upper part and were connected to each other.

Further, in this embodiment, an electrode (conductive film) is provided at the bottom of the porous body, and the electrode and the filler are electrically connected. Then, when the magnetoresistance was measured at the liquid helium temperature using the electrodeposits connected to each other overflowing above the holes and the underlying conductive film as electrodes, a change in the magnetoresistance was observed with respect to the strength and direction of the magnetic field. Was.

Since the number and arrangement of the alumina cells and the magnetic thin wires could be strictly controlled by the method of the present embodiment, it can be used as a magnetoresistive element having desired sensitivity and resistance.

Example 7 This example is an example in which PMMA was filled as a dielectric in pores to produce a nanostructure.

In this example, a nanostructure having anodically oxidized alumina regions formed at a period of 100 μm was manufactured by the same manufacturing method as in Example 1. The pore array is 30
Hexagonal arrangement at 0 nm intervals, and the thickness of anodized alumina was 4 μm. The condition of the anodization is 0.3 m for the electrolyte.
ol / l phosphoric acid solution, and the voltage was set to 120V.

Subsequently, a methacrylic acid monomer was introduced into the pores of the anodized alumina and into the gaps between the formed anodized aluminas, and calcined and polymerized at 60 ° C., thereby filling the pores with PMMA.

When the sample was sliced in the cross-sectional direction to a thickness of about 50 μm and the transmission spectrum was measured, the portion where the anodized alumina had disappeared had a sufficient transmittance in the visible region, while the region where the anodized alumina formed In the portion where the wavelength is 500 nm to 600 nm, a decrease in the transmittance was observed, indicating that the portion exhibited properties as a photonic crystal. This indicates that the present invention can be used for optical devices such as waveguides and optical recording media.

Embodiment 8 This embodiment is an example in which a nanohole is filled with a luminous body. The nanostructure of the present example was manufactured in the same manner as in Example 1.

The pore arrangement was a hexagonal arrangement at 250 nm intervals, and regions were formed at 10 μm square. Cu was used for the underlying conductive film. The conditions for the anodization were as follows: the electrolyte was a 0.3 mol / l phosphoric acid solution;
V was set.

The sample after the pore forming step was immersed together with a platinum counter electrode in an aqueous solution of 0.1 mol / l zinc nitrate kept at 60 ° C. to a voltage of −0.8 V with respect to the Ag / AgCl standard electrode. By applying a voltage, Zn
O was deposited.

When the surface of this sample was observed by FE-SEM, the anodized alumina nanoholes were regularly arranged, and Zn was contained in the anodized alumina nanoholes.
It was found that O was deposited.

As a comparative example, C containing no nanoholes was used.
ZnO was deposited on u under the same conditions. When the nanostructure of this example was irradiated with a He-Cd laser (wavelength: 325 nm), light emission with a large intensity and a narrow spectrum width was observed near a wavelength of 400 nm as compared with the comparative example. From the results of this example, it can be seen that filling the light emitting material into the pores enables the light emitting device to be used.

[0127]

As described above, the present invention has the following effects. (1) According to the present invention, the presence / absence of an alumina cell can be independently controlled for each alumina cell in units of alumina cells on the substrate by a method of forming by controlling the pore starting point. A cell array can be formed in a region. (2) In the region formation of the present invention, the region can be formed without the necessity of resist coating, pattern formation, and the like by lithography technology. Furthermore, since a latent image is formed by patterning the presence or absence of an alumina cell directly at the stage of forming a pore starting point before anodization, there is no need to align the alumina cell with a pattern required by lithography.

(3) In the region formation according to the present invention, patterning is performed in units of alumina cells, so that a structure in which the pattern boundaries coincide with the side surfaces of the alumina cells can be easily manufactured. (4) By filling the pores of the nanostructure of the present invention with materials having different dielectric constants, the nanostructure can be applied as an optical material. In particular, by associating the stored information with the shape of the pore starting point, it can be used as an optical recording medium.

(5) By filling the pores of the nanostructure of the present invention with a magnetic material, the nanostructure can be applied as a magnetic wire, a magnetic field sensor, a magnetic recording medium and the like. (6) By filling the pores of the nanostructure of the present invention with a light-emitting material, a light-emitting element with a small emission spectrum width, a laser element with a small threshold, and the like can be realized.

Further, the present invention enables the porous body of anodized alumina to be applied in various forms, and greatly expands the range of application. The nanostructure of the present invention can be used as a functional material by itself, but can also be used as a base material, a template, and the like for further novel nanostructures.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a nanostructure of the present invention;
(A) shows an isolated alumina cell, and (b) shows a linear alumina cell.

FIG. 2 is a perspective view showing an example of a nanostructure of the present invention;
(C) shows a dispersed and isolated alumina cell, and (d) shows a region-formed anodized alumina.

3A to 3C are cross-sectional views illustrating an example of a method for producing a nanostructure of the present invention, in which (a) prepares a workpiece, (b) forms pore starting points, (c) forms pores, d) area formation, (e)
Indicates packing filling.

FIG. 4 is a diagram showing a two-dimensional array of alumina cells and pores of the present invention, wherein (a) shows a square array and (b) shows a hexagonal array.

5A and 5B are diagrams illustrating an example of formation of a pore starting point by irradiation of a focused ion beam according to the present invention, wherein FIG. 5A illustrates dot formation and FIG.

FIG. 6 is a schematic view showing an anodizing apparatus.

FIG. 7 is a diagram showing a pore starting point array and the formation of regions of anodized alumina according to the present invention.
(A ') shows an alumina cell arrangement.

FIG. 8 is a diagram showing a pore starting point arrangement and the formation of regions of anodized alumina according to the present invention;
(B ') shows an alumina cell array.

FIG. 9 is a diagram showing a pore starting point array and the formation of regions of anodized alumina according to the present invention.
(C ') shows an alumina cell arrangement.

FIG. 10 is a view showing a pore starting point array and the formation of regions of anodized alumina according to the present invention;
(D ') shows an alumina cell arrangement.

11A and 11B are diagrams showing the formation of regions of anodized alumina, wherein FIG. 11A shows the formation of regions according to the present invention, and FIG. 11B shows the formation of regions by lithography.

FIG. 12 is a cross-sectional view showing a pore bottom in a base material of the anodized alumina of the present invention, in which (a) a pore bottom formed of a barrier layer, (b) is a pore bottom having a conductive path, and (c). Indicates the bottom of the penetrated pore.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Aluminum 2 Starting point of pore 3 Pores 4 Barrier layer 5 Alumina cell 6 Filling 7 Workpiece 8 Substrate 9 Anodized alumina 10 Focused ion beam 11 End face of alumina cell 12 Al film 13 Substrate 14 Starting point interval 15 Base material Reference Signs List 18 conductive path 33 unit vector 34 first pore start point 35 second pore start point 41 constant temperature bath 42 cathode 43 electrolyte 44 reaction vessel 45 power supply 46 ammeter 61 non-existent area of alumina cell 62 prepared by lithography Anodized alumina non-existing area 63 End face of anodized alumina area

Claims (20)

[Claims] 1. A nanostructure having a porous body made of alumina formed in a region on a substrate, wherein the porous body made of alumina formed in the region has an alumina cell having pores as a unit structure. A nanostructure having a structure, wherein a region is formed on the substrate in a unit of the alumina cell. 2. A nanostructure comprising an anodized alumina region formed on a substrate, wherein the anodized alumina region has a structure having an alumina cell having pores as a unit structure. A nanostructure characterized in that a region is formed on the substrate in units of cells. 3. The nanostructure according to claim 2, wherein an end face of the region of the anodized alumina formed in the area contacts an end face of the alumina cell. 4. The nanostructure according to claim 2, wherein the existence region or the non-existence region of the anodized alumina can be designated by two-dimensional lattice coordinates using the alumina cell as a unit lattice. 5. The nanostructure according to claim 2, wherein the existence region or the non-existence region of the anodized alumina can be designated by two-dimensional hexagonal lattice coordinates using the alumina cell as a unit cell. 6. The nanostructure according to claim 2, further comprising anodized alumina having a region formed of an isolated alumina cell on the substrate. 7. The nanostructure according to claim 2, further comprising anodized alumina formed in a region formed of a row of alumina cells on the substrate. 8. The nanostructure according to claim 2, wherein the nanostructure has a filler in the pore. 9. The nanostructure according to claim 2, further comprising an electrode at the bottom of the alumina cell, the electrode being electrically connected to the filler in the pore. 10. A light emitting device having a filler in pores of the nanostructure according to claim 1, wherein the filler has a light emitting function. 11. An optical device having a filler in the pores of the nanostructure according to claim 1, wherein the filler has a dielectric constant different from that of the pores. . 12. A magnetic device having a filler in pores of the nanostructure according to claim 1, wherein the filler is a magnetic material. 13. A method for producing a nanostructure comprising anodically oxidized alumina regionally formed on a substrate, wherein at least two or more types of pore starting points are formed at a site mainly composed of aluminum on the substrate. A first step, a second step of anodizing the aluminum-based portion to form anodized alumina, and eliminating a part of the anodized alumina depending on the type of the pore starting point. A method for producing a nanostructure, comprising a third step of forming a region by using the method. 14. The pore starting point has a concave shape as compared with the surroundings, and the first step of forming the pore starting point forms at least two or more types of pore starting points having different concave shapes. The method for producing a nanostructure according to claim 13, wherein the step is performed. 15. The method according to claim 13, wherein the first step of forming the pore starting point is a step of forming at least two or more kinds of pore starting points having different depths of the concave shape. 15. A method for producing a nanostructure according to item 14. 16. The method according to claim 13, wherein the pore starting point is formed by irradiating a Seito ion beam.
6. The method for producing a nanostructure according to any one of the above items 5. 17. A method for producing a nanostructure comprising anodized alumina formed regionally on a substrate, wherein at least two or more types of pore starting point arrangements are different in a region mainly composed of aluminum on the substrate. A step of forming a region, a second step of forming anodized alumina by anodizing a portion mainly containing the aluminum, and a part of the anodized alumina according to a region having a different pore starting point arrangement. A method for producing a nanostructure, comprising a third step of forming a region by causing the region to disappear. 18. The first step is a step of forming at least two or more kinds of regions having different pore start point intervals.
18. The method for producing a nanostructure according to claim 17, wherein the third step is a step of eliminating a part of the anodized alumina according to the regions having different pore start point intervals. 19. The method for producing a nanostructure according to claim 17, wherein the pore starting point is produced by irradiating a Seito ion beam. 20. A nanostructure produced by the production method according to claim 13. Description: