JP2014025124A - Method of producing mesoporous film, x ray waveguide and method of producing the same - Google Patents

Abstract

Provided is a method for producing a mesoporous film that can selectively fill micropores existing between pores of a mesoporous material and can be suitably used for electronic elements, optical elements, X-ray elements, and the like. .
A method for producing a mesoporous film comprising:
A first step of holding a mesoporous film in a container;
Introducing a gas of a compound containing silicon atoms or metal atoms at a partial pressure of 85% or more of the total pressure in the container, and exposing the mesoporous film to the gas of the compound;
And a third step of introducing a gas chemically reacting with the compound into the container and exposing the mesoporous film exposed to the compound gas to the chemically reacting gas. To do.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a mesoporous film, an X-ray waveguide, and a method for manufacturing the same. In particular, the present invention relates to a method for producing a mesoporous film that can be suitably used for electronic elements, optical elements, X-ray elements, and the like.

A mesoporous material is a porous body having uniform mesopores (pores having a pore diameter of 2 to 50 nm) formed by using a molecular aggregate of a surfactant as a template. In many cases, the pore diameter is only uniform. In addition, the arrangement of the pores has high regularity.
There are a variety of pore structures such as a two-dimensional hexagonal structure in which cylindrical pores are packed in a honeycomb structure, and many structures are known.
In the mesoporous material, it is known that supplementary micropores 302 for connecting mesopores 301 as shown in FIG. 3 exist (Non-Patent Document 1).

The regularity of the pore arrangement in this material is similar to the regularity of the atomic arrangement in the crystal. Therefore, the mesoporous material shows a clear X-ray diffraction pattern (structure period is higher than that of the crystal). Because it is an order of magnitude larger, the diffraction peak appears in a lower angle region than in the case of crystals).
The most representative mesoporous material is mesoporous silica, but in recent years, many mesoporous materials such as transition metal oxides other than silica have been reported.
Generally, mesostructured material in which the template surfactant molecular aggregate remains in the pores, and the surfactant removed from the pores by a method such as baking or extraction Is called mesoporous material. In the present invention, a state in which a surfactant is held in the pores is also referred to as a mesoporous material.
In order to adjust the size of the pore diameter of such a mesoporous material, a technique of forming an oxide in the pores by a vapor phase chemical growth method (CVD method) is known (Patent Document 1).

CHEM. COMMUN. , 2003, 98-99

JP 2012-71301 A

When the mesoporous material having the regular pore structure described above is formed as a film and used industrially as an X-ray element, optical element, electronic element, etc., the pore structure does not impair the required properties of the element. It is required to have.
For example, as shown in FIG. 3, when the micropores 302 existing between the mesopores 301 are used as an element, there arises a problem that the characteristics deteriorate as a defect.
Here, for example, when the method described in Patent Document 1 is applied to the mesoporous material, there is a possibility that the micropores 302 can be filled, but at the same time, the size of the mesopores 301 is reduced, and the structure of the material is reduced. There arises a problem that the parameter changes greatly.

  In view of the above problems, the present invention can selectively fill micropores existing between pores of a mesoporous material, and can be suitably used for electronic elements, optical elements, X-ray elements, and the like. An object of the present invention is to provide an X-ray waveguide and a manufacturing method thereof.

The method for producing the porous film of the present invention includes:
A first step of holding a mesoporous film in a container;
Introducing a gas of a compound containing silicon atoms or metal atoms at a partial pressure of 85% or more of the total pressure in the container, and exposing the mesoporous film to the gas of the compound;
A third step of introducing a gas chemically reacting with the compound into the container and exposing the mesoporous film exposed to the compound gas to the chemically reacting gas;
It is characterized by having.
The X-ray waveguide having a core and a clad according to the present invention is characterized in that the core is formed of a mesoporous film produced by the above-described method for producing a mesoporous film. The manufacturing method of the X-ray waveguide having
The core is manufactured using the mesoporous film manufactured by the method for manufacturing a mesoporous film described above.

According to the present invention, it is possible to selectively fill micropores existing between pores of a mesoporous material, and to manufacture a mesoporous film that can be suitably used for electronic elements, optical elements, X-ray elements, and the like. A method, an X-ray waveguide can be realized.
In addition, it is possible to realize an X-ray waveguide manufacturing method capable of guiding X-rays having a uniform phase with high propagation efficiency.

The conceptual diagram which shows an example of the mesoporous membrane which changed the pore with the manufacturing method of the mesoporous membrane in embodiment of this invention. The conceptual diagram of the X-ray waveguide manufactured with the manufacturing method of the mesoporous film in embodiment of this invention. The conceptual diagram of the mesoporous material in a prior art example. The figure which shows the structural example of the apparatus used for the manufacturing method of the mesoporous film in embodiment of this invention. The conceptual diagram which shows distribution of the titanium content in the silicon atomic ratio in Example 1 of this invention. The electron micrograph which shows the observation result by the transmission electron microscope of the mesoporous silica which modified the pore in Example 1 of this invention, and the mesoporous silica before modification. The figure explaining the outline | summary of the manufacturing method of the X-ray waveguide of embodiment of this invention.

Hereinafter, a method for producing a mesoporous film in the embodiment of the present invention will be described.
In the method for producing a mesoporous film according to the present embodiment, a mesoporous film formed by a known method (which can be referred to as an intermediate product in relation to the finally obtained mesoporous film) is exposed to a specific gas. A plurality of processes.
Such an exposure process modifies the microstructure of the mesoporous film.
That is, the manufacturing method of the present embodiment can be regarded as a method for modifying the pore structure of a mesoporous film, and can also be regarded as a method for producing a mesoporous film with a modified microstructure.
According to the manufacturing method of this embodiment, the micropores (302 in FIG. 3) existing between the aforementioned mesopores can be selectively filled.

FIG. 1 is a conceptual diagram showing an example of a mesoporous film in which pores are modified by the method for producing a mesoporous film of the present embodiment.
About the outline of the manufacturing method of the mesoporous film of the present embodiment,
(1) Preparation of mesoporous membrane having the same pore structure as in the past (first step)
(2) Vacuum evacuation process (3) Exposure process to compound gas containing silicon atom or metal atom (second process)
(4) Reaction gas exposure process (third process)
This will be described below.

(1) Preparation of mesoporous membrane having the same pore structure as that of the prior art A mesoporous membrane that can be modified by the present invention (a conceptual diagram is shown as an example in FIG. 3) is formed by a conventional method as described below. can do. Hereinafter, a mesoporous film having a pore structure similar to the conventional one will be described.
A porous material having pores with a pore diameter of 2 to 50 nm, and the material of the wall portion is not particularly limited, but examples thereof include oxides.
Examples of the oxide include silicon oxide, tin oxide, zirconia, titanium oxide, niobium oxide, tantalum oxide, aluminum oxide, tungsten oxide, hafnium oxide, and zinc oxide. The above oxide may contain an organic component in its skeleton.
The method for forming the mesoporous film is not particularly limited, and for example, the film can be formed by the following method. An inorganic oxide precursor is added to the solution of the amphiphile in which the aggregate functions as a template, and the inorganic oxide formation reaction proceeds. Thereafter, the template molecule is removed to obtain a porous material.

The amphiphile is not particularly limited, but a surfactant is suitable.
Examples of the surfactant molecule include ionic and nonionic surfactants. Examples of the ionic surfactant include a halide salt of trimethylalkylammonium ion.
The chain length of this alkyl chain is preferably 10 to 22 carbon atoms. As the nonionic surfactant, one containing polyethylene glycol as a hydrophilic group can be used.
As the surfactant containing polyethylene glycol as a hydrophilic group, a polyethylene glycol alkyl ether or a block copolymer of polyethylene glycol-polypropylene glycol-polyethylene glycol can be used. The chain length of this alkyl chain of the polyethylene glycol alkyl ether is preferably 10 to 22 carbon atoms, and the repeating number of polyethylene glycol is preferably 2 to 50 carbon atoms.
It is possible to change the structural period by changing the hydrophobic group and the hydrophilic group. In general, it is possible to enlarge the pore diameter by increasing the hydrophobic group and hydrophilic group.
In addition to the surfactant, an additive for adjusting the structural period may be added. As an additive for adjusting the structure period, a hydrophobic substance can be used.
As this hydrophobic substance, alkanes and aromatic compounds not containing a hydrophilic group can be used, and specifically, octane can be used.

As the precursor of the inorganic oxide, silicon or metal element alkoxide or chloride can be used.
More specifically, alkoxides and chlorides of Si, Zr, Ti, Nb, Al, Zn, and Sn can be used. As the alkoxide, methoxide, ethoxide, propoxide, or one in which a part thereof is substituted with an alkyl group can be used.
As the film forming method, a dip coating method, a spin coating method, or a hydrothermal synthesis method can be used. As a method for removing the template molecule, baking, extraction, ultraviolet irradiation, or ozone treatment can be used.
In this specification, the mesoporous material also includes a state in which a surfactant is held in the pores.

The pore structure of the obtained membrane includes a two-dimensional hexagonal structure in which cylindrical pores are packed in a honeycomb structure, and the pore structure is diverse and can take many structures. What is improved in value is a mesoporous film having cylindrical pores.
As an example of the arrangement of cylindrical pores, in a two-dimensional hexagonal structure with an ideal honeycomb-packed structure, the hexagon formed by connecting the centers of mesopores in the cross section becomes a regular hexagon. It does not have to be, and includes a distorted hexagonal structure.
Moreover, the structure which becomes a rectangle when the center of a mesopore is connected is also included.
Subsequently, a method for producing the mesoporous film of this embodiment using the above-described conventional mesoporous film having the same pore structure as a starting material will be described.

(2) Vacuum evacuation process FIG. 4 shows an example of an apparatus used in the method for producing the mesoporous film of the present embodiment. The container 409 on which the sample stage 408 is installed is provided with a vacuum pump 406 via a main valve 405, and a storage container 401 is connected via an introduction valve 410 and a storage container 402 is connected via an introduction valve 403. .
First, in the vacuum evacuation process of this embodiment, a sample (mesoporous film) to be modified is placed on a sample stage and evacuated.
The main purpose of this evacuation process is to clean the surface constituting the sample and to adjust the exposure atmosphere to the compound gas containing silicon atoms or metal atoms that follows.
The degree of evacuation is not particularly limited, but it is desirable to reach a pressure as low as possible, preferably 5 × 10 ² Pa or less, more preferably 5 × 10 ⁻⁵ Pa or less.
In addition, for the purpose described above, the sample and the entire container may be heated during this step.

(3) Compound gas exposure step containing silicon atoms or metal atoms Following the evacuation step, the introduction valve 410 is opened, a compound gas containing silicon atoms or metal atoms is introduced into the vessel 409 from the storage vessel 401, and the sample is removed. Expose.
Of the pores of the mesoporous material that is a sample in this step, a compound gas containing silicon atoms or metal atoms is preferentially adsorbed into micropores (302 in FIG. 3) that connect the mesopores.
For this purpose, in the present invention, a raw material that positively uses a carrier gas (such as an inert gas that saturates the raw material gas in order to increase the flow rate of the compound gas) as in a normal chemical vapor deposition method (CVD). It is desirable to supply the compound gas in a higher concentration state than the above supply method.
The higher the compound gas concentration of the atmosphere to be exposed, that is, the ratio of the partial pressure of the compound to the total pressure in the container, the better, and it is preferably 85% or more, more preferably 95% or more.
The temperature at the time of exposure is appropriately determined depending on the reactivity of the compound gas and the vapor pressure, but it is preferably below the temperature at which the compound gas undergoes thermal decomposition, more preferably room temperature. This state is maintained for a certain time, and the compound gas is adsorbed on the mesoporous film.

In this step, a more preferable result can be obtained by utilizing the pore size dependency of the capillary condensation phenomenon.
Capillary condensation is a phenomenon in which gas molecules are easily liquefied when placed in a minute space. In the case of mesoporous materials, the smaller the pore diameter, the easier the compound gas liquefies in the pores even at a lower pressure.
In this step, after the compound gas is introduced and held for a certain period of time as described above, the pressure is adjusted to selectively adsorb the compound gas into the micropores (302 in FIG. 3) connecting the mesopores. A large amount of state can be created.
It is desirable to adjust the internal pressure of the container to a pressure not higher than the saturated vapor pressure of the compound gas at the temperature in the container. At that time, it is desirable to reduce the total pressure stepwise.
It is suitably adjusted according to the size of the mesopores (301 in FIG. 3) and the micropores (302 in FIG. 3) connecting them, and is preferably in the range of 1/2 or less and 1/20 or more of the saturated vapor pressure, More preferably, the range is 1/5 or less and 1/20 or more. Here, the saturated vapor pressure is a gas saturation method, a static method, or the like, which is measured at each temperature for each compound gas, or an approximate expression of Clausius-Clapeyron using values measured at several temperatures. It can be a calculated value.

The compound gas used in this process includes silicon or metal atoms such as titanium, tin, zirconium, hafnium, zinc, niobium, tantalum, aluminum, iridium, etc., and has a relatively high vapor pressure and gasifies at a low temperature, and has a molecular weight Compounds in which are not too large are desirable. Examples include alkoxides, amino compounds, chlorides and the like.
Depending on the intended use of the mesoporous material modified in the present embodiment, it is preferable to select a compound containing the same element that constitutes the mesoporous material, and the combination of mesoporous silica and tetraethoxysilane is most often used.

(4) Reaction gas exposure process (third process)
Subsequent to the compound gas exposure step (3) described above, a “reaction gas” that chemically reacts with the compound gas introduced in step (3) from the introduction valve 403 to form a deposit is introduced.
The reaction gas is preferably one that causes a hydrolysis reaction or an oxidation reaction with the compound gas, and examples thereof include water vapor, wet air, and oxygen.
By this step, the compound gas that was in a state of a large amount of adsorption in the micropores (302 in FIG. 3) connecting the mesopores is decomposed and deposited as a silicon or metal compound.
In this step, it is preferable to introduce the reaction gas in a state where the final pressure in the container in the step (3) is maintained.
After this step, nitrogen gas is introduced from the leak valve 404, the container 409 is returned to atmospheric pressure, and a sample is taken out.
After this step, the sample may be taken out after performing high vacuum evacuation (for example, about 1 × 10 ⁻⁵ Pa, which may be combined with container heating) for cleaning the inside of the container.
By the production method of the present invention described above, the micropores existing between the mesopores can be selectively filled with a silicon or metal compound. FIG. 1 is a conceptual diagram showing an example of a mesoporous film in which pores are modified in the present invention.

Hereinafter, an X-ray waveguide manufacturing method using the mesoporous film manufactured by the manufacturing method of the present embodiment as a core will be described.
The X-ray waveguide manufactured by the manufacturing method of this embodiment is an X-ray waveguide that includes a clad and a core and confines X-rays in the core by total reflection at the interface between the core and the clad. The X-ray waveguide has a core (mesoporous film having cylindrical pores) in which a plurality of substances having different real parts of the refractive index are periodically arranged.
In such an X-ray waveguide, a mode in which X-rays guided through the core cause multiple interference and efficiently guide in accordance with this periodic structure is selected. It is possible to guide uniform X-rays.

The X-ray wave guiding principle used in the X-ray waveguide manufactured according to the present invention will be described.
Here, X-rays are electromagnetic waves in a wavelength band where the real part of the refractive index of the substance is 1 or less.
Specifically, the X-ray in the present invention refers to an electromagnetic wave having a wavelength of 100 nm or less including extreme ultraviolet light (Extreme Ultra Violet (EUV) light). In this specification, an electromagnetic wave having a wavelength of 1 pm to 100 nm is referred to as X-ray.
Further, in the specification, when the electromagnetic wave is simply referred to, it may be used synonymously with the X-ray.
The frequency of electromagnetic waves with short wavelengths such as X-rays is very high, and the outermost shell electrons of the substance cannot respond. It is known that the real part of the refractive index of a substance is smaller than 1 for a line.
The refractive index n of a substance with respect to such X-rays is generally obtained by using a deviation δ from the real part 1 and β ′ of the imaginary part related to absorption as represented by the following formula (1). It is expressed as

n = 1−δ−iβ ′ = n′−iβ ′ Formula (1)

Since δ is proportional to the electron density ρ _e of the substance, the higher the electron density, the smaller the real part of the refractive index. The real part n ′ of the refractive index is 1−δ.
Furthermore, ρ _e is proportional to the atomic density ρ _a and the atomic number Z.
As described above, the refractive index of a substance with respect to X-rays is represented by a complex number. In this specification, the real part is referred to as the real part of the refractive index or the real part of the refractive index, and the imaginary part is the imaginary part of the refractive index or the refractive index. Called the imaginary part.
For example, X-rays have the largest real part of the refractive index when propagating in a vacuum, and the real part of the refractive index of air is maximized for almost all substances that are not gases in a general environment. In this specification, the term “substance” includes air and vacuum. Since the mesoporous film has portions having different refractive indexes between the pore portion and the wall portion, the mesoporous film is composed of a plurality of substances.

Next, the X-ray waveguide manufactured by the manufacturing method of this embodiment will be described.
The X-ray waveguide according to the present embodiment is configured to guide the X-ray by confining the X-ray in the core by total reflection at the clad, and the core includes a periodic structure including a plurality of substances having different real refractive indexes. By having this, a periodic resonant waveguide mode described later is developed. The basic principle of the X-ray waveguide that exhibits the periodic resonance waveguide mode will be described.
An X-ray waveguide that expresses a periodic resonant waveguide mode forms a waveguide mode by confining the X-ray in the core having a periodic structure by total reflection at the interface between the core and the cladding, and propagates the X-ray. .
In this waveguide, the critical angle for total reflection at the interface between the core and the cladding is larger than the Bragg angle due to the periodicity of the periodic structure of the core.

FIG. 2 shows a conceptual diagram of this X-ray waveguide.
This X-ray waveguide has a form in which a core 2001 is sandwiched between a clad 2002 and a clad 2003.
The core 2001 is formed by laminating a basic structure composed of a substance 2005 having a high refractive index real part and a substance 2006 having a low refractive index real part. 2007 represents the total reflection critical angle at the interface between the clad and the core, 2008 represents the Bragg angle, and 2009 represents the total reflection critical angle at the material interface in the basic structure.
In FIG. 2, the total reflection critical angle θ _{c-total at} the interface between the clad and the core, the total reflection critical angle θ _c-multi at the interface of each layer constituting the basic structure in the multilayer film, and the Bragg attributed to the periodicity of the multilayer film An example of the angle θ _B is shown.
In the present specification, these angles are expressed by assuming that the direction parallel to the plane of the film is 0 °. The advancing direction of the arrow X-ray in the figure is shown.

The total reflection critical angle θ from the direction parallel to the film surface, where n _{clad is} the real part of the refractive index of the clad material at the interface between the clad and the core, and n _core is the real part of the refractive index of the material on the core side. _c-total (°) is expressed by the following equation (2), where n _clad <n _core .

Assuming that the period of the periodic structure of the core is d and the real part of the average refractive index of the periodic structure as the core is _navg , an approximate Bragg like the following formula (3) regardless of the presence or absence of multiple diffraction in the core The angle θ _B (°) is defined. Here, m is a constant, and λ is the wavelength of X-rays.

The physical property parameter of the substance constituting the X-ray waveguide, the structural parameter of the waveguide, and the wavelength of the X-ray are designed to satisfy the following formula (4).

By satisfying Equation (4), the waveguide mode with an effective propagation angle such as the Bragg angle due to the periodicity of the core, which is a periodic structure, is always confined in the core by the cladding, contributing to the propagation of X-rays. Can be made.
In this specification, the effective propagation angle θ ′ (°) is expressed by the following equation (5) using the wave number vector (propagation constant) k _z in the propagation direction of the waveguide mode and the wave number vector k ₀ in vacuum. It shall be represented by
Since k _z is constant at the interface of each layer due to the continuous condition, as shown in FIG. 3, the effective propagation angle θ ′ (°) is the propagation constant k _z of the fundamental wave of the waveguide mode and the wave vector k _{0 in} vacuum. The angle at which the fundamental wave of the guided mode travels in a vacuum.
Since this can be considered to roughly represent the propagation angle of the fundamental wave of the guided mode in the core, it will be used for future explanation.

Here, the periodic structure that forms the core is assumed to be a structure in which a plurality of substances having different real parts of the refractive index are periodically stacked. At this time, the total reflection critical angle due to the difference in the real part of the refractive index exists at the adjacent film interface. This is θ _c-multi (°).

When the total reflection critical angle in the periodic structure is smaller than the Bragg angle due to periodicity as in the above formula (6), X incident on the interface in the periodic structure at an angle equal to or greater than the Bragg angle. The line does not cause total reflection but will cause partial reflection or refraction. Since the periodic structure is composed of a plurality of layers having different real parts of refractive index that are periodically stacked, there are also multiple interfaces in the stacking direction, and X-rays inside the periodic structure are repeatedly reflected and refracted at these interfaces. It becomes. Such repeated reflection and refraction of X-rays inside the periodic structure causes multiple interference.
As a result, an X-ray having a condition capable of resonating with the periodic structure, that is, a propagation mode that can exist inside the periodic structure is formed. As a result, a waveguide mode is formed in the core of the X-ray waveguide structure. . This is referred to as a periodic resonance waveguide mode.

Each of such periodic resonant waveguide modes has an effective propagation angle, and the effective propagation angle of the periodic resonant waveguide mode having the smallest effective propagation angle appears near the Bragg angle of the periodic structure.
Since the periodic resonant waveguide mode is a mode that resonates with the periodicity of the periodic structure, it is referred to as a periodic resonant waveguide mode in this specification. This corresponds to a propagation mode satisfying the lowest order band when the periodic structure is considered as a one-dimensional photonic crystal with an infinite number of periods, and this propagation mode is confined by total reflection at the interface between the cladding and the core. Become.
In an actual one-dimensional periodic structure, since the number of periods is finite, the photonic band structure deviates from the photonic band structure of the one-dimensional periodic structure with an infinite period. However, the waveguide mode increases as the number of periods increases. The characteristic approaches that on a photonic band with an infinite period.
The Bragg reflection is caused by the effect of the photonic band gap due to periodicity, and the Bragg angle, which is the angle that gives the Bragg reflection, is slightly larger than the effective propagation angle of the periodic resonant waveguide mode.

In a photonic band structure having a periodic structure, a waveguide mode that resonates with the periodic structure exists at the end of the photonic band gap.
When the effective propagation angle of the waveguide mode is considered with the X-ray energy constant, the waveguide mode having a relatively small effective propagation angle among these waveguide modes is the lowest-order periodic resonant waveguide mode. .
In the spatial distribution profile of the electric field intensity of the periodic resonant waveguide mode, the number of antinodes of the electric field intensity basically matches the number of periods of the periodic structure.
The position of the antinode of the higher-order periodic resonant waveguide mode having an effective propagation angle corresponding to the higher-order Bragg angle is basically a natural number multiple of 2 or more of the number of periods.

Further, in a periodic structure having a finite number of periods, there may be a waveguide mode that propagates at an angle other than the effective propagation angle of the periodic resonant waveguide mode as described above.
These are waveguide modes that exist when the entire periodic structure, which is the core, not the periodic resonant waveguide mode, is considered as a uniform medium with the average real part of the refractive index averaged. The impact is small.
On the other hand, in the periodic resonant waveguide mode realized by the configuration of the X-ray waveguide, the electric field is more concentrated at the center of the core as the number of periods of the periodic structure increases, and the leakage into the clad decreases. Propagation loss is reduced.
In addition, the envelope curve of the electric field intensity distribution has a shape biased toward the center of the core, and the loss due to the seepage into the clad is further reduced.
Furthermore, the phase of the periodic resonant waveguide mode used in this X-ray waveguide is uniform in the direction with high periodicity, that is, in the direction perpendicular to the interface between the cladding and the core and perpendicular to the waveguide direction. Can have typical coherence.
Here, the fact that the waveguide modes are in phase not only corresponds to the fact that the phase difference of the electromagnetic field in the plane perpendicular to the waveguide direction is zero, but also corresponds to the spatial refractive index distribution of the periodic structure. This also means that the phase difference of the electromagnetic field periodically changes between −π and + π.
In this periodic resonant waveguide mode, the phase of the electric field changes between −π and + π in the direction perpendicular to the waveguide direction at the same period as the period of the periodic structure.

In the mesoporous film that is the core based on the above-described principle, the periodicity of the refractive index composed of the cylindrical pore and the wall is important.
In the structure in which the micropores 302 exist between the cylindrical pores 301 as shown in FIG. 3, the periodicity of the wall portion and the cylinder pore portion is impaired, and the expression of the periodic resonance waveguide mode and the propagation efficiency are lowered. There is a case.
The X-ray waveguide manufactured in this embodiment has preferable characteristics by adopting a structure in which micropores between cylindrical pores are filled with a wall material as shown in FIG. 1 by the pore modification method according to this embodiment. To express.

An outline of the method of manufacturing the X-ray waveguide according to the present embodiment will be described with reference to FIG. First, the clad 702 is formed on the substrate 700 (7-b).
The X-ray waveguide according to the present embodiment guides the X-ray by confining the X-ray in the core (and the flattening layer) by total reflection at the cladding.
In the X-ray region, a substance having a higher electron density has a smaller real part of the refractive index. Therefore, it is preferable to use a metal having a high density as the material used for the cladding.
Specifically, a simple substance of Os, Ir, Pt, Au, W, Ta, Hg, Ru, Rh, Pd, Pb, and Mo, or a material containing these elements can be used.
In addition, the X-ray waveguide related to the present embodiment is designed so as to satisfy the above formulas (2) to (4) between the material forming the core and the material used for the clad. There is a case.
A clad using such a material can be formed by sputtering, vapor deposition, or the like.
Although the thickness of this clad varies depending on the material, it is required to be thick enough to sufficiently confine X-rays in the core and thin from the viewpoint of cost and manufacturing. The thickness of the cladding is preferably 1 nm to 300 nm, and more preferably 1 nm to 50 nm. The clad is preferably formed with a film thickness distribution in the X-ray waveguide.
For example, for the purpose of positively incident from the cladding surface, a thin film is formed in the incident region to improve introduction efficiency, while in other regions, a thick film is formed to enhance the X-ray confinement effect. Is preferably performed.

Next, a mesoporous film is formed on the clad 702 as the core 701.
The method for forming the mesoporous film is appropriately selected from the methods described in (1). Subsequently, the micropores between the cylindrical pores are filled by the pore modifying method of the present invention according to steps (2) to (4) (7 -C).
Next, a clad 703 is formed on the core 701 formed as described above (7-d). The clad material and formation method are as described above.
An X-ray waveguide can be formed as described above.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
[Example 1]
As Example 1, an example in which titania is formed in micropores existing between cylindrical pores of a mesoporous silica film will be described.
In the formation of the mesoporous silica film of this example, first, a precursor solution of mesoporous silica was added to a solution obtained by adding ethanol, 0.01M hydrochloric acid, and tetraethoxysilane for 20 minutes, and then an ethanol solution of a block polymer was added for 3 hours. Prepared by stirring.
As a block polymer, ethylene oxide (20) propylene oxide (70) ethylene oxide (20) (hereinafter referred to as EO (20) PO (70) EO (20) (in parentheses are the number of repetitions of each block)) It was used.
It is also possible to use methanol, propanol, 1,4-dioxane, tetrahydrofuran, or acetonitrile instead of ethanol.
The mixing ratio (molar ratio) was tetraethoxysilane: 1.0, hydrochloric acid: 0.0011, ethanol: 5.2, block polymer: 0.0096, and ethanol: 3.5. The solution can be appropriately diluted and used for the purpose of adjusting the film thickness.

The precursor solution was dip-coated on the cleaned substrate using a dip coater at a pulling rate of 0.5 mms ⁻¹ .
After film formation, the film was held in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 40% for 24 hours, and then baked in a baking furnace at 400 ° C. for 1 hour.
From the X-ray diffraction analysis of the deposited mesoporous silica film using the Bragg-Brentano configuration, this mesoporous silica film has high ordering in the normal direction of the substrate surface, and its surface spacing, that is, the period in the confinement direction. Was confirmed to be 10 nm. The film thickness was approximately 300 nanometers.
Next, in the evacuation step, the formed mesoporous silica film was placed on the sample stage 408 of the apparatus of FIG. 4 and evacuated to 5 × 10 ⁻⁵ Pa.
Next, in order to clean the silica surface, the sample stage was heated to 300 ° C. and held for 1 hour, and then returned to room temperature.

Next, the exposure process to organic titanium compound gas was performed as follows.
Following the evacuation step, the introduction valve 410 was opened to evaporate titanium tetraisopropoxide in the storage container 401 and introduce it into the container 409.
The openings of the introduction valve 410 and the main valve 405 were adjusted so that the pressure of the diaphragm type vacuum gauge 411 was 1 Pa, and maintained at room temperature for 10 hours (here, the vapor pressure of titanium tetraisopropoxide at room temperature was It was a value of 8 Pa when measured by the static method in advance.)
In this step, titanium tetraisopropoxide molecules were preferentially adsorbed into micropores (302 in FIG. 3) connecting the mesopores among the pores of the mesoporous silica film.

Next, the reactive gas exposure process was performed as follows.
Subsequently, the introduction valve 403 was opened to evaporate the water in the storage container 402 and introduce it into the container 409.
The introduction valve 403 was adjusted so that the pressure of the diaphragm-type vacuum gauge 411 was 3 Pa, and kept at room temperature for 2 hours. By this step, among the pores of the mesoporous silica film, titanium tetraisopropoxide that was in a state of a large amount of adsorption in the micropores (302 in FIG. 3) connecting the mesopores was decomposed by reacting with water. , Deposited as titania in the micropores.
After this step, the container 409 was heated at 150 ° C. for 2 hours while the main valve 405 was fully opened and the container 409 was evacuated. Then, after cleaning the inside of the container (reaching a vacuum degree of about 4 × 10 ⁻⁶ Pa), the leak valve 404 was opened, nitrogen gas was introduced, the container 409 was returned to atmospheric pressure, and a sample was taken out.

In this example, the mesoporous film after pore modification was evaluated as follows.
After the above step, nitrogen gas was introduced from the leak valve 404 to return the container 409 to atmospheric pressure, and the mesoporous film was taken out.
And the depth direction analysis was performed from the film surface to the substrate interface direction by X-ray photoelectron spectroscopy. As a result, as shown in FIG. 5, it was found that titanium was present relatively uniformly from the film surface to the vicinity of the substrate interface, and about 20% of titanium in terms of silicon atomic ratio was introduced into the film.
In addition, it was confirmed from the binding energy position by X-ray photoelectron spectroscopy that titanium atoms exist as titania.

FIG. 6 shows the observation results of the mesoporous silica whose pores are modified in this example and the mesoporous silica before the modification using a transmission electron microscope.
It was confirmed that the size of the cylindrical pores did not change before and after the modification.
Further, when the pore size distribution of the mesoporous silica before and after the pore modification is estimated by the nitrogen gas adsorption method, the pore volume of 6 nm in diameter corresponding to the cylindrical pore is maintained before and after the modification, and the fine diameter of 1 nm or less is maintained. It was confirmed that the pore volume decreased after the modification.
As described above, the micropores existing between the cylindrical pores of the mesoporous silica film could be selectively filled with titania.

[Example 2]
As Example 2, an example in which silica is formed in micropores existing between cylindrical pores of a mesoporous silica film will be described.
A 400 nm mesoporous silica film is formed by the same method as in Example 1.
In the vacuum evacuation step, the formed mesoporous silica film is placed in a vacuum of 5 × 10 ⁻⁵ Pa by the same method as in Example 1.
Next, in the exposure process to the organic silica compound gas, following the evacuation process, the introduction valve 410 is opened to evaporate tetraethoxysilane in the storage container 401 and introduce it into the container 409.
The opening degree of the introduction valve 410 and the main valve 405 is adjusted so that the pressure of the diaphragm type vacuum gauge 411 becomes 20 Pa, and is held for 10 hours at room temperature (here, the vapor pressure of tetraethoxysilane at room temperature As a result of measurement by the method, a value of 240 Pa is obtained).
In this step, among the pores of the mesoporous silica film, tetraethoxysilane molecules are preferentially adsorbed to the micropores (302 in FIG. 3) that connect the mesopores.

Next, in the reaction gas exposure step, subsequently, the introduction valve 403 is opened to evaporate the water in the storage container 402 and introduce it into the container 409.
The introduction valve 403 is adjusted so that the pressure of the diaphragm type vacuum gauge 411 is 40 Pa, and after holding at room temperature for 2 hours, nitrogen gas is introduced from the leak valve 404 to return the container 409 to atmospheric pressure, and the mesoporous membrane Take out.
As described above, the micropores existing between the cylindrical pores of the mesoporous silica film can be filled with silica.
The selective formation of silica in the micropores can be confirmed by the change in the pore diameter distribution from the nitrogen gas adsorption isotherm, as in Example 1.

[Example 3]
As Example 3, an example in which titanium oxide is formed in micropores existing between mesopores of a mesoporous titanium oxide film will be described.
In forming the mesoporous titanium oxide film, first, a precursor solution is prepared by adding an ethanol solution of a block polymer to an aqueous solution in which titanium chloride is mixed and stirring for 3 hours.
As the block polymer, EO (106) PO (70) EO (106) is used.
The mixing ratio (molar ratio) is titanium chloride: 1.0, water: 10.0, block polymer: 0.005, and ethanol: 40.0.
A dip coater is used to dip coat the precursor solution on the cleaned substrate.
After film formation, the film is held in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 60% for 24 hours, and then baked in a baking furnace at 400 ° C. for 1 hour to form a 300 nm mesoporous zirconium oxide film.

Next, in the vacuum evacuation step, the formed mesoporous titania film is placed in a vacuum of 5 × 10 ⁻⁵ Pa by the same method as in Example 1.
Next, in the exposure process to the organic titanium compound gas, following the evacuation process, with the containment vessel 401 heated to 70 ° C., the introduction valve 410 is opened to evaporate titanium tetraisopropoxide and put it in the vessel 409. Introduce.
The opening degree of the introduction valve 410 and the main valve 405 is adjusted so that the pressure of the diaphragm type vacuum gauge 411 becomes 8 Pa, and is held at room temperature for 10 hours.
Subsequently, the opening degree of the introduction valve 410 and the main valve 405 is adjusted so that the pressure of the diaphragm type vacuum gauge 411 becomes 0.5 Pa, and is held at room temperature for 1 hour.

Next, in the reaction gas exposure step, subsequently, the introduction valve 403 is opened to evaporate the water in the storage container 402 and introduce it into the container 409.
The introduction valve 403 is adjusted so that the pressure of the diaphragm type vacuum gauge 411 is 3 Pa, and after holding at room temperature for 2 hours, nitrogen gas is introduced from the leak valve 404 to return the container 409 to atmospheric pressure, and the mesoporous membrane Take out.
As described above, the micropores existing between the mesopores of the mesoporous titanium oxide film can be filled with titanium oxide.

[Example 4]
As Example 4, an example in which tin oxide is formed in micropores between mesopores of mesoporous zirconium oxide will be described.
In forming a mesoporous zirconium oxide film, first, a precursor solution is prepared by adding a butanol solution of a block polymer to an aqueous solution obtained by mixing 12M hydrochloric acid and zirconium chloride and stirring for 3 hours.
As the block polymer, EO (20) PO (70) EO (20) is used. The mixing ratio (molar ratio) is zirconium chloride: 1.0, hydrochloric acid: 2.0, water: 6.0, block polymer: 0.013, butanol: 9.0.
Spin coating is performed by dropping the prepared solution onto the cleaned substrate. Spin coating is performed for 15 seconds at 25 ° C. and a relative humidity of 40% with a substrate rotation speed of 3000 rpm.
After film formation, the film is kept in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 95% for 30 hours, and then baked in a baking furnace at 400 ° C. for 1 hour to form a 400 nm mesoporous zirconium oxide film.

Next, in the vacuum evacuation step, the formed mesoporous zirconium oxide film is placed in a vacuum of 5 × 10 ^{−5 Pa by the same} method as in Example 1.
Next, in the exposure process to the organotin compound gas, following the evacuation process, the introduction valve 410 is opened and the tetraisopropoxytin is opened while the container 409, the sample stage 408, and the storage container 401 are heated to 130 ° C. Is evaporated and introduced into the container 409. The opening degree of the introduction valve 410 and the main valve 405 is adjusted so that the pressure of the diaphragm type vacuum gauge 411 becomes 100 Pa, and is held at room temperature for 10 hours.
Subsequently, the opening degree of the introduction valve 410 and the main valve 405 is adjusted so that the pressure of the diaphragm type vacuum gauge 411 becomes 10 Pa, and is held at room temperature for 1 hour.

Next, in the reaction gas exposure step, subsequently, the introduction valve 403 is opened to evaporate the water in the storage container 402 and introduce it into the container 409.
The introduction valve 403 is adjusted so that the pressure of the diaphragm type vacuum gauge 411 becomes 20 Pa, and after holding at room temperature for 2 hours, nitrogen gas is introduced from the leak valve 404 to return the container 409 to atmospheric pressure, and the mesoporous membrane Take out.
As described above, the micropores existing between the mesopores of the mesoporous zirconium oxide film can be filled with tin oxide.

[Example 5]
As Example 5, an example in which silica is formed in micropores existing between cylindrical pores of a mesoporous silica film by the same method as in Example 2 and used as a core of an X-ray waveguide will be described.
As the formation of the clad, a clad 702 made of W (tungsten) is formed on the Si substrate to a thickness of about 15 nanometers by a sputtering method (7-b). Further, as the formation of the mesoporous silica film, by the same method as in Example 1, only the pulling speed of the dip coater is changed to ¹ mms ⁻¹ , and 500 nm mesoporous silica is formed on the clad 702 (7-c).
Next, in the evacuation step, the formed mesoporous silica film is placed in a vacuum of 5 × 10 ⁻⁵ Pa by the same method as in Example 1.
Next, in the formation of silica in the inter-cylinder micropores, subsequently, an exposure step to tetraethoxysilane and a reaction gas exposure step are performed in the same manner as in Example 2. Thereby, the micropore which exists between cylindrical pores of a mesoporous silica film can be filled with silica.
The selective formation of silica in the micropores can be confirmed by the change in the pore diameter distribution from the nitrogen gas adsorption isotherm, as in Example 1.
In forming the clad, a clad 703 made of W (tungsten) is formed on the mesoporous silica film. This clad is deposited by sputtering to a thickness of approximately 15 nanometers.
Through the above steps, an X-ray waveguide having a mesoporous silica film to which the pore modifying method of the present invention is applied as a core is manufactured.

The X-ray waveguide characteristics are measured as follows.
That is, 10 keV X-rays were incident on the waveguide, and the intensity of the X-rays guided by the periodic resonance waveguide mode was measured.
Compared to an X-ray waveguide using as a core a mesoporous silica film that has not undergone pore modification according to the present invention, it is considered that a waveguide strength that is approximately twice as large is observed.
It is considered that the factor that increases the waveguide strength is that the periodicity of the refractive index composed of the cylindrical pore portion and the silica wall portion is improved by the pore modification method of the present invention. As described above, according to the manufacturing method of the present invention, the micropores existing between the mesopores of the mesoporous material can be selectively filled, so that the electronic device, the optical device, the X-ray device, etc. When used, a mesoporous film in a preferable form can be obtained.

101; mesopore 201; core 202; clad 203; clad 204; unit structure 205; material 206 having a real part of high refractive index; material 207 having a real part of low refractive index; critical angle of total reflection at the interface between the clad and the core 208; Bragg angle 209; critical angle of total reflection at the material interface in the basic structure

Claims (16)

A method for producing a mesoporous film,
A first step of holding a mesoporous film in a container;
Introducing a gas of a compound containing silicon atoms or metal atoms at a partial pressure of 85% or more of the total pressure in the container, and exposing the mesoporous film to the gas of the compound;
A third step of introducing a gas chemically reacting with the compound into the container and exposing the mesoporous film exposed to the compound gas to the chemically reacting gas;
A method for producing a mesoporous film, comprising:   The method for producing a mesoporous film according to claim 1, wherein the second step includes a step of gradually reducing the total pressure.   2. The method according to claim 1, wherein the third step includes a step of introducing a gas chemically reacting with the compound into the container in which the final total pressure in the second step is maintained. A method for producing a mesoporous film according to claim 2.   4. The method according to claim 1, wherein the second step includes a step of introducing the gas of the compound at a partial pressure that is 95% or more of the total pressure in the container. 5. A method for producing a mesoporous film.   The mesoporous film production according to any one of claims 1 to 4, wherein the second step includes a step of maintaining the total pressure in the container at a pressure equal to or lower than a saturated vapor pressure of the compound. Method.   6. The method according to claim 1, wherein the second step includes a step of maintaining the total pressure in the container at a pressure in the range of 1/2 or less and 1/20 or more of the saturated vapor pressure of the compound. The method for producing a mesoporous film according to any one of the above.   6. The method according to claim 1, wherein the second step includes a step of maintaining the total pressure in the container at a pressure in the range of 1/5 or less and 1/20 or more of the saturated vapor pressure of the compound. The method for producing a mesoporous film according to any one of the above.   8. The temperature according to claim 1, wherein a temperature at which the mesoporous film is exposed to a gas of a compound containing a silicon atom or a metal atom in the second step is a room temperature. 9. A method for producing a mesoporous film.   The metal element contained in the compound is the same element as the metal element constituting the wall material of the mesoporous film held in the first step, according to any one of claims 1 to 8. A method for producing the mesoporous film as described.   The mesoporous film according to any one of claims 1 to 9, wherein the element contained in the compound is silicon, and the wall material of the mesoporous film held in the first step is silica. Production method.   The method for producing a mesoporous film according to any one of claims 1 to 10, wherein the gas that chemically reacts with the compound is a gas containing water vapor.   The method for producing a mesoporous film according to any one of claims 1 to 11, wherein the mesoporous film held in the first step has cylindrical pores. An X-ray waveguide having a core and a cladding,
An X-ray waveguide, wherein the core is formed of a mesoporous film manufactured by the method according to any one of claims 1 to 12.   The total reflection critical angle at the interface between the core and the clad with respect to an X-ray having a wavelength of 1 pm or more and 100 nm or less is smaller than a Bragg angle caused by a periodic structure of the mesoporous material of the core. 14. An X-ray waveguide according to 13. A method of manufacturing an X-ray waveguide having a core and a cladding,
An X-ray waveguide manufacturing method, wherein the core is manufactured using a mesoporous film manufactured by the mesoporous film manufacturing method according to any one of claims 1 to 12. The total reflection critical angle at the interface between the core and the clad with respect to an X-ray having a wavelength of 1 pm or more and 100 nm or less is smaller than a Bragg angle caused by a periodic structure of the mesoporous material of the core. 15. A method for producing an X-ray waveguide according to 15.

Images