JP2006255811A - Monomolecular film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monomolecular film forming method for forming a homogeneous monomolecular film in a predetermined region on a substrate without the need for a complicated device and a great amount of waste liquid treatment and for forming a two-dimensional array structure consisting of a plurality of different monomolecular film regions on the same substrate without undergoing multiple processes. <P>SOLUTION: First, a coupling agent 2 of alkoxysilane is applied to a predetermined region on the surface of the substrate subjected to hydrophilizing treatment, using a manipulator 3. Then, in the state of being held for a certain time in a non-oxygen atmosphere containing no oxygen under predetermined humid environment, the silane coupling agent 2 reacts with the surface of the substrate and the silane coupling agent 2 is fixed to the substrate 1. When different silane coupling agents 2a, 2b, 2c are applied to predetermined positions on the substrate, the two-dimensional array structure is manufactured in one process where nano materials different in type are fixed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for forming a monomolecular film on a surface of a substrate, and more specifically, forms a monomolecular film uniformly in a predetermined region of a substrate without requiring a complicated apparatus and a large amount of waste liquid treatment. Furthermore, the present invention relates to a method for forming a monomolecular film that enables a two-dimensional array structure composed of a plurality of different monomolecular film regions to be formed on the same substrate without going through a multi-step process.

Monomolecular films formed on the surface of a substrate that can be hydrophilized, such as silicon, glass, and polymers, can be used as substitutes for resists used in semiconductor microfabrication technology (Non-Patent Documents 1 to 3) and biodevices (Non-Patent Documents). The adaptation as 4-6) is attracting attention. This is because the monomolecular film covers a predetermined position on the surface of the substrate, so that the base material such as silicon having semiconductivity, insulating glass, and flexible organic film has a nanoscale thickness. This is because it is the only unique material that can freely control the surface properties of only the coated part without impairing the peculiarity of the material.
When using the above monomolecular film as a resist substitute material or biodevice, it is necessary to dispose a plurality of different monomolecules in a two-dimensional pattern at a predetermined position on the substrate surface in a uniform and high resolution manner. is there.

  Conventionally, such a monomolecular film has been formed by a vapor phase method (Patent Document 1), a liquid phase method (Non-Patent Document 7), and a coating method (Patent Document 2). The fine processing of the surface of the monomolecular film following this formation is performed by ultraviolet lithography (Patent Document 1), electron beam lithography (Patent Document 3) represented by semiconductor processes, anodization using a scanning probe microscope or scratch ( Non-patent document 8), microcontact printing using a polymer template (non-patent documents 1 to 3) was mainly used. Without using such post-lithography, hexamethyldisilazane is used as an organic monomolecular raw material, and applied to any position on a silicon substrate coated with oxide silicon using a scanning probe microscope. It has been reported that one type of single molecule can be formed only at a predetermined position above (Non-patent Document 9). Further, by using ultraviolet lithography, two kinds of organic monomolecules are transferred to predetermined positions on a silicon substrate coated with oxide silicon through a vapor phase method (Non-patent Document 10) or a liquid phase method (Patent Document 4). It has been reported that each membrane region can be disposed.

JP 2000-282240 A Japanese Patent Laid-Open No. 06-079167 JP 2004-119524 A Japanese Patent Laid-Open No. 06-289627 Y. Xia et al., 1998, Angew. Chem. Int. Ed. Engl. 37, 551 W. J. et al. Dressick et al., 1993, J. Am. J. et al. Appl. Phys. 32, 5829 N. Shirahata et al., 2005, Chem. Mater. 17 pages, 20 pages R. Jelinek et al., 2004, Chem. Rev. 104, 5987 Yoshio Ishimori, 2003, Surface Science, 24, 671 C. M.M. Halliwell et al., 2001, Anal. Chem. 73, 2476 A. Ulman, 1996, Chem. Rev. 96, 1533 S. Kramer et al., 2003, Chem. Rev. 103, 4367 A. Ivanisevic et al., 2001, J. MoI. Am. Chem. Soc. 123, 7887 L. Hong, et al. 2003, Langmuir, 19: 1966

  As described above, conventionally, a monomolecular film is formed on the entire surface of a substrate by a vapor phase method or a liquid phase method, and then a monomolecular film pattern is formed by performing lithography using a fine processing technique. Therefore, for example, in the ultraviolet lithography, it is possible to dispose the second monomolecular film in the region where the monomolecular film has been removed by the ultraviolet irradiation, but the third and fourth different types of monomolecules. It was extremely difficult to create the region. Similarly, the post-lithography method using a scanning probe microscope can be processed at an extremely fine nano level compared to the optical lithography method, but in order to form multiple types of monomolecular regions on the same substrate. Has yet to be achieved because it has to go through a multi-step process. In addition, there is no example in which a plurality of types of monomolecular regions are produced by the technique achieved by applying using a scanning probe microscope without using post lithography.

  Under such circumstances, the present inventors have conducted extensive research in view of the above prior art, and as a result, the substrate surface has been previously hydrophilized, and a silane composed of alkoxysilane is formed at a predetermined position on the surface. By applying a substance having a coupling agent and holding the substrate under a predetermined humidity environment in a non-oxygen atmosphere, it is possible to form a single molecule only in the applied region. By applying a substance having a silane coupling agent made of silane to each predetermined place and holding the substrate under a predetermined humidity environment in a non-oxygen atmosphere, a plurality of different kinds of monomolecular films made of different types in one step The inventors have found that it is possible to produce each region at a predetermined position on the same substrate, and have completed the present invention.

  That is, the object of the present invention is to apply a plurality of different types of silane coupling agents, which has been difficult in the past, after applying each silane coupling agent on the same substrate in advance, and in a non-oxygen atmosphere. To provide a method for forming a monomolecular film, which allows two-dimensional array of monomolecular microregions to be formed on the same substrate in a one-step process by holding the substrate in a humidity environment of It is in.

  Another object of the present invention is to make it possible to form a monomolecular film for most of the silane coupling agent to be applied to the substrate surface, and to fix rare biomaterials and nanomaterials, etc. An object of the present invention is to provide a method for forming a monomolecular film capable of forming a sufficient monomolecular film in an amount.

Another object of the present invention is that it does not require a complicated lithography and immersion step in a solvent, does not require a high-temperature reaction field for forming a monomolecular film as found in a vapor phase method, and is found in a liquid phase method. Another object of the present invention is to provide a method for forming a monomolecular film capable of drastically solving the production of a large amount of waste liquid.
Furthermore, another object of the present invention is to develop a next-generation nanolithography source that does not have a limiting factor such as a wavelength in optical lithography and can be applied to a nanoscale minute region in the microstructuring. An object of the present invention is to provide a method for forming a monomolecular film that can be applied to a biological material having low resistance to X-rays, electron beams, and light.

In order to achieve the above object, the present invention holds a substrate in a predetermined humidity and oxygen-free atmosphere after applying a silane coupling agent composed of alkoxysilane to the surface of the substrate subjected to a hydrophilic treatment. Thus, a monomolecular film is formed on the substrate surface. In particular, the predetermined humidity is preferably 22% or less. Preferably, the substance constituting the silane coupling agent reacts with the substrate surface and is fixed onto the substrate by a covalent bond.
With the above configuration, a monomolecular film pattern can be formed by applying a silane coupling agent to a predetermined region of the substrate surface that has been subjected to a hydrophilic treatment. For this reason, there is no need to make a fine structure by a conventional photolithography method or the like.
Therefore, the present invention can also be applied to substances having low resistance to X-rays and light, for example, biomaterials such as DNA. At the same time, unlike the conventional optical lithography and the like, there is no factor depending on the wavelength of the fine structure, so that it can be applied up to a nanoscale minute region.
In addition, a monomolecular film can be formed at a much lower temperature than a vapor phase method typified by a CVD (Chemical Vapor Deposition) method. Further, compared with the liquid phase method, the waste liquid can be greatly reduced, which is environmentally friendly and energy saving. Moreover, since the silane coupling agent can be applied in a necessary amount, the cost performance is remarkably good. In addition, rare metal materials, biomaterials, nanomaterials, and the like can be immobilized on the substrate.

Preferably, the substance constituting the silane coupling agent has an alkoxide at the terminal. The substance constituting the silane coupling agent is methoxysilane or ethoxysilane. In particular, the substance constituting the silane coupling agent may have a methoxy group or an ethoxy group at the terminal and a carbon chain having 3 to 22 carbon atoms.
Preferably, the substance constituting the silane coupling agent is methyl group, fluoro group, amino group, phenyl group, mercapto group, cyano group, sulfonic acid group, carboxyl group, carbonyl group, halogen, formyl group, nitro group, nitroso group. A substance terminated with a functional group such as a group, an azo group, a diazo group or a hydroxyl group.
In addition, the substance constituting the silane coupling agent may be a substance bonded to sugar, oligonucleotide, DNA, peptide, nanoparticle, fullerene, nanotube, or nanomaterial.
With the above configuration, a monomolecular film can be formed if the silane coupling agent applied to the substrate surface has alkoxysilane. Therefore, these functional groups, atomic groups, and nanomaterials can be arranged on the outermost surface of the substrate by using alkoxylsilane bonded to various functional groups, atomic groups, and nanomaterials as a coupling agent.

Preferably, the substrate is silicon oxide, indium oxide, alumina, iron oxide, tin oxide, titanium oxide, zinc oxide or other oxide ceramics, or silicon coated with an oxide ceramic thin film, diamond, silicon carbide, graphite. It consists of any other inorganic base material, polyethylene terephthalate covered with a carbonyl group, diol or other polar functional group by hydrophilic treatment, polyimide, polyester or other organic film, or a material that can be terminated with a hydrophilic group.
With the above configuration, since the substrate surface is made of a material capable of terminating with a hydrophilic group, by subjecting the substrate surface to a hydrophilic treatment, the silane coupling agent comes into contact with water and hydrolyzes to generate a silanol group. The silanol group reacts with the hydrophilic group on the substrate surface and can be immobilized on the substrate surface by a covalent bond.

Preferably, the silane coupling agent is applied to the surface of the substrate by a scanning probe microscope, a manipulator, a microsyringe, a syringe, a polymer template, or an ink jet method, so that a single molecule is formed on a predetermined minute region on the substrate. A film is formed.
With the above structure, a monomolecular film can be formed by applying a silane coupling agent to the substrate surface in any size from a nano-order microscopic region to a centimeter-order macroscopic region.

  Preferably, the silane coupling agent is dissolved and applied in a solvent so as to have a concentration of 1 to 20% by volume. Thereby, even if a silane coupling agent is solid at normal temperature, it can apply | coat to a substrate surface by dissolving with a solvent.

  Preferably, a plurality of types of substances are used as the silane coupling agent applied to the substrate surface, and the plurality of types of different substances are applied to a plurality of minute regions on the same substrate. With this configuration, after applying a plurality of types of silane coupling agents to each region of the same substrate surface, a plurality of types of substances are applied to the substrate in a one-step process of holding the substrate in an oxygen-free atmosphere. It can be arranged.

  According to the present invention, a silane coupling agent made of alkoxysilane is applied to the surface of the substrate that has been subjected to a hydrophilic treatment, and the substrate is held in a non-oxygen atmosphere at a predetermined humidity, and then the excess material is removed. Thus, a uniform monomolecular film can be formed on the substrate surface. Therefore, a complicated post-lithography process and a solvent immersion process are not required, and it is possible to apply to a monomolecular resist, to form a two-dimensional array of nanomaterials, and to form a chip, which has been difficult until now. Thereby, according to this invention, various devices, such as a biochip, a molecular device, a semiconductor chip, a display, can be produced.

Hereinafter, the best mode for carrying out the present invention will be described.
In the present invention, a monomolecular film can be formed on a substrate through the following steps.
FIG. 1 is a diagram schematically showing a step of forming a monomolecular film on a substrate 1 as a method for forming a monomolecular film of the present invention. In FIG. 1, a nanomaterial having alkoxyl silane at the terminal is used as the silane coupling agent 2, and this nanomaterial is applied to a predetermined region on the surface of the substrate 1 using a manipulator 3, and a monomolecular film is formed. It is assumed that the surface of the substrate 1 is partially covered with a film-like nanomaterial.

First, the coupling agent 2 made of alkoxylsilane is applied to a predetermined region on the substrate surface. Here, the substrate surface is previously hydrophilized and covered with a superhydrophilic natural oxide film. For example, as shown in FIG. 1A, the silane coupling agent is attached to the tip of the manipulator 3 by moving the manipulator 3 up and down.
Next, as shown in FIG. 1B, the substrate is moved onto the substrate 1 that has been subjected to a hydrophilic treatment and terminated with a hydroxyl group (—OH). When the manipulator 3 moves over the region where the monomolecular film is to be formed, the manipulator 3 is moved to the surface of the substrate 1 and the silane coupling agent 2 is applied to the substrate surface as shown in FIG. To do.

  Next, the substrate 1 is held for a certain period of time in a non-oxygen atmosphere not containing oxygen and in a predetermined humidity environment. As a result, the silane coupling agent 2 applied to the substrate surface reacts with the substrate surface, and the silane coupling agent 2 is fixed to the substrate as shown in FIG. Thereafter, excess substances such as a silane coupling agent are removed by, for example, ultrasonic cleaning treatment.

  Through the above processing, a monomolecular film region can be formed only at a predetermined position on the substrate 1 as shown in FIG. At this time, the monomolecular film is fixed to the substrate surface by a bond of silicon Si and oxygen O (—Si—O—). Thereby, a substrate partially covered with the nanomaterial can be manufactured.

Hereinafter, each process will be specifically described in detail.
The substrate 1 may be any substrate that can be hydrophilized, that is, any substrate that can terminate the substrate surface with a hydrophilic group such as a hydroxyl group. For example, oxide ceramics such as silicon oxide and indium oxide may be used. Further, an inorganic base material such as silicon, diamond, silicon carbide, and graphite coated with such an oxide ceramic thin film may be used. Furthermore, an organic film such as polyethylene terephthalate, polyimide, or polyester covered with a polar functional group such as a carbonyl group or a diol by a hydrophilization surface treatment may be used.

In advance, the substrate 1 is hydrophilized. At that time, impurities adhering to the substrate surface are removed by washing or the like.
When a silicon substrate is used as the substrate 1, for example, surface treatment is performed on the silicon substrate with oxygen plasma, or surface treatment is performed by irradiating ultraviolet rays, electron beams, ozone, or the like in an atmosphere in which oxygen exists. . In particular, it is preferable to use ultraviolet light having a wavelength of 185 nm or less. Thereby, the hydrophilization treatment can be performed by forming a silicon oxide film on the surface of the silicon substrate 1.
Here, whether the substrate surface has been made hydrophilic can be determined based on whether or not the contact angle of water on the substrate surface is 5 ° or less.

Next, the silane coupling agent 2 is applied to a predetermined minute region on the substrate surface.
As the silane coupling agent 2, a substance made of alkoxysilane is used. For example, if the molecule has a molecular structure capable of forming a monomolecular film, the compound is terminated with an alkoxylane, Any substance can be used.
Here, alkoxysilane is used as the silane coupling agent 2 because chlorosilane used in the liquid phase method is extremely reactive to water molecules, generates hydrogen chloride, and is handled in the atmosphere. This is because alkoxysilane does not have such inconvenience. The generated hydrogen chloride is not preferable because it is not environmentally friendly and is not suitable for use under a scanning probe microscope when performing nanolithography.

By the way, as the silane coupling agent 2, for example, any of aliphatic hydrocarbons and aromatic hydrocarbons can be used. However, the silane coupling agent 2 needs to be a compound having a terminal terminated with an alkoxysilane, and has various functional groups. A substance modified with an atomic group, a nano substance, or the like can also be used.
Examples of the aliphatic hydrocarbons include methoxys such as octadecyltrimethoxysilane, allyloxyundecyltrimethoxysilane, and hexadecyltriethoxysilane, and ethoxys.
As various functional groups and atomic groups, for example, methyl group, fluoro group, amino group, phenyl group, mercapto group, cyano group, sulfonic acid group, carboxyl group, carbonyl group, halogen, formyl group, nitro group, nitroso group, An azo group, a diazo group, a hydroxyl group, etc. can be mentioned. Furthermore, as a silane coupling agent having these functional groups and atomic groups, for example, triethoxysilylundecanal, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, 11-bromoun Examples include decyltrimethoxysilane.
Examples of nanomaterials include sugars, nanoparticles, oligonucleotides, fullerenes and the like. Moreover, the substance couple | bonded with these nano substances may be sufficient, for example, 3-galactoxypropyl trimethoxysilane, a silicon nanoparticle terminal trimethoxysilane, a triethoxysilyl oligonucleotide, a triethoxysilyl fullerene etc. can be mentioned.
Here, the aliphatic hydrocarbon and aromatic hydrocarbon used for the formation of the monomolecular film are not limited by the size of the molecule, but the carbon number is 3 to 22, preferably 11 to 22. Hydrocarbons composed of hydrogen chains may be used.
The silane coupling agent 2 is not limited to the above substances, and may be a substance having an alkoxysilane equivalent or similar to these.

Such a silane coupling agent 2 is applied to a predetermined position on the hydrophilically treated substrate surface in the atmosphere. At this time, if the silane coupling agent 2 is liquid at the coating temperature like octadecyltrimethoxysilane, it can be used as it is or can be used in a solution dissolved in a non-aqueous solvent. In the case of a substance that is not liquid at room temperature but is solid at room temperature, it is preferable to apply a solution dissolved in a non-aqueous organic solvent.
Here, as for the concentration of the solution, a suitable concentration is determined depending on the type of the silane coupling agent 2, the nature of the solvent, the coating method, the apparatus, and the like. The inside is preferable. Or it is preferable to apply | coat what melt | dissolved the silane coupling agent 2 so that it might become 1-20 volume% density | concentration with a solvent.
At this time, if the concentration of the silane coupling agent 2 is much higher than 20% by volume, depending on the substance to be monomolecularized, it may be aggregated and precipitated in the solution, which is not preferable. Conversely, a diluted solution with a concentration of 1% by volume is also possible, but if it is thinner, it is not preferred because it needs to be reacted for a long time to form a single molecule.

  By the way, when apply | coating the silane coupling agent 2, according to the magnitude | size of the area | region to apply, a scanning probe microscope, a manipulator, a micro syringe, a micro pipette etc. can be used, for example. Moreover, you may apply | coat using apparatuses and instruments other than these. The coating conditions are arbitrarily set according to the properties of the substance forming the monomolecular film, the coating method and apparatus, the pattern shape, dimensions, etc. of the monomolecular film.

Next, when the silane coupling agent 2 is applied to the surface of the substrate in this way, it is held in a predetermined environment. That is, the silane coupling agent 2 is maintained in a non-oxygen atmosphere in a predetermined humidity environment, preferably in a low humidity environment of 22% or less so as not to react with oxygen. Here, the non-oxygen atmosphere means an oxygen-free atmosphere such as nitrogen gas, argon, helium, or the like that is substantially free of oxygen, for example, under vacuum. The holding time is preferably 24 hours or longer. At this time, excess water reacts with the silane coupling agent 2 and inhibits the unimolecular reaction in order to cause polymerization and crystallization. However, it has been confirmed that single molecule formation is possible under the humidity of 22% or less. Although the upper limit of humidity has not been confirmed, in order to realize a reproducible reaction, the humidity is preferably a low humidity of 22% or less.
Thereby, the hydrophilic group on the substrate surface reacts with the silane coupling agent to form a single molecule. At this time, for example, by heating to about 70 ° C., the single molecule formation reaction can be promoted. Thereby, in the area | region where the silane coupling agent 2 was apply | coated among the substrate surfaces, the apply | coated substance is fixed to the substrate surface by a covalent bond.

And the substance which is not fixed to the substrate surface but remains in the coating region by physical adsorption is removed by washing. For example, it is removed by ultrasonic cleaning with an organic solvent. Examples of the solvent include acetone, dichloromethane, ethanol and the like, but are not particularly limited thereto. Further, for example, a normal ultrasonic oscillation device used for ultrasonic cleaning such as power consumption 110 W, high frequency power 80 W, transmission frequency 38 kHz, etc. can be used. This ultrasonic process is completed in about 30 minutes.
Here, the lift-off of removing the remaining substance can be performed at room temperature or in the atmosphere.

As described above, the silane coupling agent 2 is covalently bonded by applying the silane coupling agent 2 to the hydrophilized substrate surface and then holding the substrate in a non-oxygen atmosphere and under a predetermined humidity environment. And a monomolecular film can be formed on the surface of the substrate. At this time, as a silane coupling agent, by using a substance having an alkylsilane bonded to the functional group, atomic group, and nanomaterial as described above, a monomolecular film is formed by coating on the substrate surface, A substance having a functional group or an atomic group appears on the uppermost surface of the substrate and exhibits surface properties such as reactivity.
Furthermore, it is possible to impart properties such as molecular recognition by reacting the surface with, for example, a protein. Therefore, it can be set as the two-dimensional array structure utilized for a protein chip etc.

Next, a method for forming a monomolecular film pattern will be described as an application of the present invention.
First, the silane coupling agent 2 is applied to a predetermined position on the substrate surface to form a monomolecular film in a predetermined pattern. In the present invention, for example, a monomolecular film pattern can be formed with an accuracy of about 500 nm to 1 mm. In order to form a minute region, for example, a pattern of about 1 nm to 200 nm, it is preferable to use a scanning probe microscope. On the contrary, in order to form a wide area, for example, a pattern of about 1 mm to 1 cm, it is preferable to use a microsyringe or a micropipette.
In this way, the silane coupling agent 2 is applied to the substrate surface in accordance with a predetermined pattern, and is held on the substrate 1 through a covalent bond by being held in a non-oxygen atmosphere under a predetermined low humidity environment. A monomolecular film pattern can be formed.

Next, as an application of the present invention, it will be described that a two-dimensional array structure can be formed by applying a plurality of kinds of substances as the silane coupling agent 2 to each predetermined region on a substrate. .
FIG. 2 is a diagram schematically showing a process of simultaneously forming different types of monomolecular films on a substrate as a method for forming a monomolecular film of the present invention. In addition, the same code | symbol is attached | subjected to the same thing as FIG. FIG. 2 shows three types of nanomaterials having alkoxyl silane at the end as the silane coupling agents 2a, 2b, and 2c, and after applying these nanomaterials to each predetermined region on the surface of the substrate 1 using the manipulator 3, A case where a monomolecular film of various types is formed and the surface of the substrate 1 is partially covered with a monomolecular film-like nanomaterial to produce a two-dimensional array structure in which different types of nanomaterials are immobilized is shown. Yes.

Coupling agents 2a, 2b and 2c made of alkoxyl silane are applied in advance to a predetermined region on the substrate surface. Here, the substrate surface is previously hydrophilized and covered with a superhydrophilic natural oxide film. That is, as shown in FIG. 2A, the substrate surface is terminated with a hydroxyl group (—OH) having hydrophilicity. Specifically, the silane coupling agents 2a, 2b, 2c are sequentially attached to the tip of the manipulator 3, the manipulator 3 is moved to the surface of the substrate 1, and the silane coupling agents 2a, 2b, 2c are moved to the substrate surface. Apply to.
Next, as in the case of FIG. 1, the substrate 1 is held for a certain period of time in a non-oxygen atmosphere not containing oxygen and in a predetermined humidity environment.
As a result, the silane coupling agents 2a, 2b, 2c applied to the substrate surface react with the substrate surface to be immobilized on the substrate 1. Thereafter, surplus substances such as silane coupling agents 2a, 2b, 2c are removed by ultrasonic cleaning.

Through the above processing, as shown in FIG. 2B, the silane coupling agents 2a, 2b, and 2c react with the substrate surface at the respective positions on the substrate 1, and the substrate 1 is reacted with the silane coupling agent 2a. , 2b, 2c, monomolecular film regions 1a, 1b, 1c can be formed. In this way, by applying different types of silane coupling agents 2a, 2b, 2c in a predetermined pattern to each minute region on the same substrate 1, a plurality of different monomolecular film regions 2a, 2b, A two-dimensional array structure composed of 2c can be formed on the same substrate 1.
According to this method, by applying each silane coupling agent 2a, 2b, 2c to a predetermined position on the substrate 1, it is possible to dispose a plurality of substances on the same substrate 1 at predetermined positions. it can. For this reason, since each pattern is formed in the coating process, formation of the first type of single molecule, removal of unnecessary portions, formation of the second type of single molecule, etc., as in the conventional vapor phase method or liquid phase method, etc. It is not necessary to repeat the above processing operation, and it is possible to form a two-dimensional array structure composed of many types of single molecules on the same substrate by a single processing operation. Further, according to this method, a precise pattern shape can be performed by a simple operation.

  Thus, the product can be selected by arbitrarily selecting the type of substrate 1, the type and combination of substances having silane coupling agents 2 a, 2 b, and 2 c made of alkoxysilane, the silane coupling agent made of alkoxysilane, and the like. By designing, fine structure of monomolecular coating, which has been difficult with the prior art, and also two-dimensional array formation on the same substrate, easy operation and desired product in one step process Can be realized.

Next, examples will be shown, but the present invention is not limited to the following examples.
In Example 1, a monomolecular pattern of octadecyltrimethoxysilane was formed on the surface of a silicon substrate.
First, an octadecyltrimethoxysilane is applied to a silicon substrate surface coated with a natural oxide film exhibiting superhydrophilicity, using a manipulator, and is arrayed four times so as to form a circular shape having a diameter of 20 μm to a predetermined position on the substrate surface. It was applied to.
Next, it was left at room temperature for 48 hours in an argon atmosphere having a relative humidity of 16%. Finally, ultrasonic cleaning treatment was performed for 5 minutes each in acetone, dichloromethane, ethanol, and ultrapure water. By this series of treatments, a pattern of octadecyltrimethoxysilane monomolecular film was formed on the surface of the silicon substrate.
In addition, in order to measure the contact angle of water droplets simultaneously with the pattern formation of the monomolecular film, octadecyltrimethoxysilane was applied in a circular shape having a diameter of 5 mm on the same substrate.

The sample on which the monomolecular film pattern of the example was formed was observed with a frictional force electron microscope using a silicon cantilever covered with a natural oxide film by ultraviolet cleaning in the atmosphere.
FIGS. 3A and 3B show the results of observation of the sample produced in Example 1 with a frictional force electron microscope, wherein FIG. 3A shows a frictional force electron microscope image, and FIG. 3B shows frictional characteristics. FIG. 3 (a) is an image of the difference in frictional characteristics between four domains terminated with methyl groups in a circular shape having a diameter of 20 μm on the sample surface and silica as a non-terminated portion. The scale interval inscribed on the shaft is 20 μm. FIG. 3B is a cross-sectional image of the difference in friction characteristics in the portion indicated by the white line in FIG. 3A. The horizontal axis indicates each position, and the vertical axis indicates the magnitude of the frictional force.
As is apparent from FIG. 3, four circular methyl group-terminated domains (regions) having a diameter of 20 μm were obtained as contrast images. This low contrast portion (black portion) is a microregion covered with a monomolecular film of octadecyltrimethoxysilane. In addition, when a contact angle was measured by dropping a water drop on a portion coated in a circular shape having a diameter of 5 mm, it was 108 °.

(Comparative Example 1)
Next, Comparative Example 1 corresponding to Example 1 is shown.
In Comparative Example 1, a monomolecular film pattern of octadecyltrimethoxysilane was formed on the surface of a silicon substrate by using a vapor phase method and photolithography.
First, a silicon substrate coated with a natural oxide film showing super hydrophilicity was placed in an autoclave together with a sample bottle containing octadecyltrimethoxysilane.
Next, after heating to 150 ° C. for 3 hours in nitrogen, gradually cooling to room temperature, and sonicating in acetone, dichloromethane, ethanol, and ultrapure water for 5 minutes each, octadecyltrimethoxysilane A substrate whose entire surface was covered with a monomolecular film was obtained. At this time, the water droplet contact angle on the monomolecular surface was measured to be 108 °.
Finally, after placing a predetermined photomask on the monomolecular film, the surface of the monomolecular film patterned in the same manner as in Example 1 was formed by irradiating ultraviolet light under a vacuum of about 10 Pa.

When Example 1 and Comparative Example 1 were compared, first, it was found that the coating method of Example 1 did not require a heating treatment as compared with the vapor phase method of Comparative Example 1 in terms of monomolecular formation.
Next, in terms of microstructuring, the coating method of Example 1 does not need to produce a photomask according to the pattern and has a high degree of freedom in the production pattern compared to the photolithography method of Comparative Example 1. I understood. In addition, it was found that the coating method of Example 1 can greatly simplify the process because single molecule formation and lithography can be performed simultaneously.

In Example 2, a monomolecular film pattern of N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane was formed on the surface of a silicon substrate.
First, a manipulator in which a nanochip having an inner diameter of 500 nm and N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane is mounted on the surface of a silicon substrate coated with a natural oxide film exhibiting super hydrophilicity is used. Then, it was applied in an array form four times so as to form a circular shape having a diameter of 500 nm at a predetermined position on the substrate surface.
Next, it was left at room temperature for 48 hours in an argon atmosphere having a relative humidity of 22%.
Finally, ultrasonic cleaning treatment was performed for 5 minutes each in acetone, dichloromethane, ethanol, and ultrapure water. By this series of treatments, a monomolecular film pattern of N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane was formed on the silicon substrate surface.
In addition, in order to measure the contact angle of water droplets simultaneously with the pattern formation of the monomolecular film, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane is formed in a circular shape having a diameter of 5 mm on the same substrate. It was applied to.

The sample thus formed with the monomolecular film pattern was observed with an electrostatic force microscope using a gold-coated silicon cantilever having a spring constant of 3N. 4 is a diagram showing a frictional force microscope image observed in Example 2. FIG. The illustrated image shows a difference in potential characteristics between four domains terminated with amino groups and a silica domain as a non-terminated portion on a silicon substrate covered with a natural oxide film.
As apparent from FIG. 4, four circular portions having a diameter of 500 nm show domains terminated with amino groups, and this domain was obtained as a high contrast image. This high-contrast portion (white portion) is a microregion covered with N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane. In addition, when a contact angle was measured by dropping a water droplet on a portion coated in a circular shape having a diameter of 5 mm, it was 61 °.

(Comparative Example 2)
Next, Comparative Example 2 corresponding to Example 2 is shown.
In Comparative Example 2, a monomolecular film pattern of N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane was formed on the surface of a silicon substrate by using an immersion method (liquid phase method) and anodization. Formed.
First, a silicon substrate covered with a super-hydrophilic natural oxide film is placed in toluene containing 1.0% by volume of N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane in a nitrogen atmosphere. Then, the silicon substrate subjected to hydrophilic treatment is immersed and held for 3 hours.
Next, the substrate is taken out, subjected to ultrasonic treatment for 5 minutes each in acetone, dichloromethane, ethanol, and ultrapure water, and then subjected to heat treatment in a 120 ° C. drying furnace for 10 minutes, whereby N- (2-aminoethyl) A monomolecular film substrate of -11-aminoundecyltrimethoxysilane was obtained. At this time, the water droplet contact angle on the monomolecular surface was 61 °.
Subsequently, by a scanning atomic force microscope (AFM) mode of a scanning probe microscope (SPM) (manufactured by Seiko Instruments Inc., SPI3800N), a conductive probe (manufactured by Seiko Instruments Inc., Micro Cantilever Type: SI-AF01-).
Af = 12 kHzC = 0.12 N / mCoat: Au), a predetermined portion of the substrate surface covered with this N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane monomolecule is applied with an applied voltage of 7 V ( The sample was anodized in the atmosphere under conditions of +) and 0.1 μ / s to form a pattern of N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane.

Example 2 and Comparative Example 2 are compared.
First, in terms of monomolecular formation, it was found that the coating method of Example 2 drastically reduces waste liquid treatment compared to the liquid phase method of Comparative Example 2.
Next, with regard to microstructuring, that is, nanolithography of about 500 nm, it was found that the coating method of Example 2 is much easier than the anodic oxidation using the cantilever of Comparative Example 2. In addition, in the anodic oxidation, it was found that the oxide film in the region where the monomolecule was peeled off bulges several nm in a convex shape, and it is not easy to form the next monomolecular film in that region. In addition, it was found that the coating method of Example 2 can greatly simplify the process because single molecule formation and lithography can be performed simultaneously.

In Example 3, octadecyltrimethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, heptadecafluoro-1,1,2,2-tetrahydrodecyltrimethoxy were formed on the same silicon substrate surface. Each monomolecular film of silane and triethoxysilylundecanal was formed to produce a microarray.
First, octadecyltrimethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, heptadecafluoro-1,1, are coated on the surface of a silicon substrate covered with a natural oxide film exhibiting super hydrophilicity. 2,2-tetrahydrodecyltrimethoxysilane and triethoxysilylundecanal were applied side by side to a predetermined position on the substrate surface in a circular shape having a diameter of 5 μm using a manipulator.
Next, it was left at room temperature for 48 hours in an argon atmosphere having a relative humidity of 20%.
Finally, ultrasonic cleaning treatment was performed for 5 minutes each in acetone, dichloromethane, ethanol, and ultrapure water. A microarray was produced by this series of processes.

The microarray produced in Example 3 was observed with an electrostatic force microscope using a gold-coated silicon cantilever having a spring constant of 3N.
5A is an electrostatic force microscope image observed in Example 3, and FIG. 5B is an explanatory diagram thereof. The figure is an image obtained by observing a region of the microarray where octadecyltrimethoxysilane and heptadecafluoro-1,1,2,2-tetrahydrodecyltrimethoxysilane are applied with an electrostatic force microscope. This image is an image of the difference in potential characteristics between a domain terminated with a methyl group and a fluoro group and silica as a non-terminated portion.

As is clear from FIG. 5, the brightest portion 11 with the highest contrast is the silica region, and the next highest-contrast portion 12 is a minute region covered with a single molecule of octadecyltrimethoxysilane, and the contrast is dark. Portion 13 is a microregion covered with heptadecafluoro-1,1,2,2-tetrahydrodecyltrimethoxysilane.
In other words, the background with the brightest part covered with silanol groups, followed by a 5 μm domain terminated with a methyl group, and finally a 3 μm domain terminated with a fluoro group. An image consisting of a region having an electric potential was observed.

(Comparative Example 3)
Next, Comparative Example 3 corresponding to Example 3 is shown.
In Comparative Example 3, octadecyltrimethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, and heptadecafluoro- were formed on the same silicon substrate surface by using a vapor phase method and photolithography. A monomolecular film of 1,1,2,2-tetrahydrodecyltrimethoxysilane and triethoxysilylundecanal was formed.

First, a silicon substrate coated with a natural oxide film showing super hydrophilicity was placed in an autoclave together with a sample bottle containing octadecyltrimethoxysilane and heated to 150 ° C. in nitrogen for 3 hours.
Next, after gradual cooling to room temperature, ultrasonic treatment was performed for 5 minutes each in acetone, dichloromethane, ethanol, and ultrapure water. By this series of treatments, a monomolecular coated substrate of octadecyltrimethoxysilane was obtained.
Next, after putting a predetermined photomask on the monomolecular film, a patterned monomolecular surface was obtained by irradiating ultraviolet light under a vacuum of about 10 Pa.

The substrate was then placed in an autoclave with a sample bottle containing hepadecafluoro-1,1,2,2-tetrahydrodecyltrimethoxysilane and heated to 150 ° C. for 3 hours in nitrogen. . Then, after gradual cooling to room temperature, ultrasonic treatment was performed for 5 minutes each in acetone, dichloromethane, ethanol, and ultrapure water. By this series of treatments, a monomolecular coated substrate of octadecyltrimethoxysilane was obtained.
Thereafter, a predetermined photomask was placed on the monomolecular film, and then irradiated with ultraviolet light under a vacuum of about 10 Pa to obtain a substrate having a methyl region, a fluoro region, and a silanol region.

Further, this substrate was placed in an autoclave together with a sample bottle containing a solution obtained by diluting N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane seven times with toluene, and the mixture was placed in nitrogen. Heat to 150 ° C. for 3 hours. Then, after gradual cooling to room temperature, ultrasonic treatment was performed for 5 minutes each in acetone, dichloromethane, ethanol, and ultrapure water. By this series of treatments, a substrate having a methyl region, a fluoro region, and an amino region was obtained.
Next, a predetermined photomask was placed on the monomolecular film, and then irradiated with ultraviolet light under a vacuum of about 10 Pa to obtain a silanol region for forming an aldehyde region. The substrate was then placed in an autoclave with a sample bottle containing a solution of trimethoxyundecanol diluted 7-fold with toluene and heated to 130 ° C. in nitrogen for 3 hours. And after slow cooling to room temperature, the substrate which has a methyl area | region, a fluoro area | region, an amino area | region, and an aldehyde area | region was obtained by performing ultrasonic treatment for 5 minutes each in acetone, a dichloromethane, ethanol, and an ultrapure water.

Example 3 and Comparative Example 3 are compared.
First, in terms of single molecule formation, it was found that the coating method of Example 3 did not require a heating treatment as compared with the vapor phase method of Comparative Example 3.
Next, in terms of microstructuring, the coating method of Example 3 does not need to produce a photomask according to the pattern and has a high degree of freedom in the production pattern compared to the photolithography method of Comparative Example 3. I understood. In addition, it was found that the coating method of Example 3 can greatly simplify the process because single molecule formation and lithography can be performed simultaneously.
In addition, regarding the point of forming a two-dimensional array, in a method using photolithography or the like as in Comparative Example 3, when a method of covering the entire surface with one kind of monomolecular film by a vapor phase method or the like is adopted in advance, Since it is necessary for forming the second and third monomolecular films, it is obvious that the steps, costs, and amount of waste liquid are enormous.
On the other hand, in Example 3, a substance for forming a plurality of monomolecular films is applied in advance to a predetermined location on the substrate, and the applied substrate is held in a low humidity and non-oxygen atmosphere. Thus, it can be seen that a two-dimensional array can be produced in one step at room temperature, which is preferable from all angles including problems such as steps required for production, cost, and waste liquid treatment.

The method for forming a monomolecular film of the present invention can form a monomolecular film uniformly in a predetermined region of a substrate without requiring a complicated apparatus and a large amount of waste liquid treatment as in the prior art. In addition, a two-dimensional array structure composed of a plurality of different monomolecular film regions can be formed on the same substrate without going through a conventional multi-step process.
Further, it is possible to form a two-dimensional array pattern composed of a plurality of different monomolecular regions that cannot be achieved by the conventional vapor phase method, immersion method, or the like. Therefore, in the fields of chemistry, biochemistry, applied physics, medicine, etc., nanotechnology, which is expected as a basic technology that supports the next generation of industry, organic monomolecular film formation technology, which is attracting attention as a next generation resist material, biotechnology It is extremely useful in a wide range of technical fields such as sensors, bioarrays, molecular devices, gas sensors, displays, and resist substitute materials for semiconductor microfabrication technology.

Conventionally, semiconductor devices and biodevices have been increasingly miniaturized following the progress of nanotechnology, and the photolithography method, which is an essential micronuclear technology in the current device industry, has reached the wavelength limit of light. Therefore, alternative post-lithography technology such as an electron beam is required. However, according to the present invention, an organic single molecule that has been spotlighted as a next-generation resist is a lithography technology that is completely different from the concept of post-lithography. Thus, it is possible to finely process even a processing dimension that cannot be achieved by an optical process.
Furthermore, according to the present invention, it is also possible to arrange nanomaterials that are extremely difficult to handle in a pattern assuming a device without using a post-lithography method.

It is the figure which showed typically the process of forming a monomolecular film on a board | substrate as a formation method of the monomolecular film of this invention. It is the figure which showed typically the process of forming simultaneously the monomolecular film of a different kind on a board | substrate as a formation method of the monomolecular film of this invention. The result observed with the frictional force electron microscope of the sample produced in Example 1 is shown, (a) is a figure which shows a frictional force electron microscope image, (b) is a figure which shows a friction characteristic. 6 is a diagram showing a frictional force microscope image observed in Example 2. FIG. It is the (a) electrostatic force microscope image observed in Example 3, (b) It is the explanatory drawing.

Explanation of symbols

1: substrate 1a, 1b, 1c: monomolecular film region 2, 2a, 2b, 2c: silane coupling agent 3: manipulator

Claims (12)

  A monomolecular film is formed on the substrate surface by applying a silane coupling agent composed of alkoxysilane to the surface of the substrate that has been subjected to a hydrophilic treatment, and then holding the substrate in an atmosphere that does not contain oxygen at a predetermined humidity. And forming a monomolecular film.   The method for forming a monomolecular film according to claim 1, wherein the predetermined humidity is 22% or less.   The method for forming a monomolecular film according to claim 1, wherein a substance constituting the silane coupling agent reacts with the substrate surface and is fixed onto the substrate by a covalent bond.   The method for forming a monomolecular film according to claim 1, wherein the substance constituting the silane coupling agent has an alkoxide at a terminal.   The method for forming a monomolecular film according to claim 1, wherein the substance constituting the silane coupling agent is methoxysilane or ethoxysilane.   The method for forming a monomolecular film according to claim 1, wherein the substance constituting the silane coupling agent has a methoxy group or an ethoxy group at a terminal and a carbon chain having 3 to 22 carbon atoms. .   The substance constituting the silane coupling agent is methyl group, fluoro group, amino group, phenyl group, mercapto group, cyano group, sulfonic acid group, carboxyl group, carbonyl group, halogen, formyl group, nitro group, nitroso group, The method for forming a monomolecular film according to any one of claims 1 to 6, which is a substance terminated with an azo group, a diazo group or a functional group of a hydroxyl group.   The substance constituting the silane coupling agent is a substance bonded to sugar, oligonucleotide, DNA, peptide, nanoparticle, fullerene, nanotube, or nanomaterial, according to any one of claims 1 to 7, A method for forming a monomolecular film as described.   The substrate is silicon oxide, indium oxide, alumina, iron oxide, tin oxide, titanium oxide, zinc oxide or other oxide ceramics, or silicon, diamond, silicon carbide, graphite or other inorganic groups coated with an oxide ceramic thin film. It is composed of either a material, polyethylene terephthalate, polyimide, polyester or other organic film covered with a carbonyl group, diol or other polar functional group by the hydrophilization treatment, or a material that can be terminated with a hydrophilic group. The method for forming a monomolecular film according to claim 1.   The silane coupling agent is applied to the substrate surface by a scanning probe microscope, a manipulator, a microsyringe, a syringe, a polymer template, or an ink jet method, thereby forming a monomolecular film in a predetermined minute region on the substrate. The method for forming a monomolecular film according to claim 1, wherein:   The method for forming a monomolecular film according to claim 1, wherein the silane coupling agent is dissolved and applied in a solvent so as to have a concentration of 1 to 20% by volume.   2. The method according to claim 1, wherein a plurality of types of substances are used as silane coupling agents applied to the substrate surface, and the plurality of types of different substances are applied to a plurality of minute regions on the same substrate. A method for forming a monomolecular film as described.