JP2002169303A - Pattern forming method and electronic device, optical element and photocatalytic member each produced by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern forming method by which fine patterning with a metal oxide can directly be carried out on a substrate by treatment at ordinary temperature or treatment at a relatively low temperature and to inexpensively provide various high density electronic devices having a high degree of integration, a high functional optical element and a photocatalytic member to markets by utilizing the pattern forming method. SOLUTION: The pattern forming method comprises a step for forming a hydrophobic film having a photosensitive hydrophobic group on a substrate, a step for forming a hydrophilic pattern by irradiating the hydrophobic film formed on the substrate with light and a step for depositing a metal oxide for enhancing pattern resolution on the hydrophilic pattern particularly by putting the substrate with the formed hydrophilic pattern in an atmosphere of a hydrolyzable metal oxide precursor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method, and more particularly, to a metal oxide suitable for application to the manufacture of various electric and electronic parts such as a semiconductor integrated circuit (IC), a connector or a capacitor of a DRAM. And a method of forming a pattern. The present invention also relates to a method for forming a pattern of a photocatalytic metal oxide, which is suitable for application of a photocatalyst having a function of decomposing an organic substance and a function of hydrophilizing a surface to hardness by excitation of light, which is suitable for enhancing the functionality.

[0002]

2. Description of the Related Art Conventionally, for example, a semiconductor integrated circuit (IC)
When manufacturing electronic components such as electric / electronic circuit boards or DRAM capacitors, a printing method such as screen printing is used as a method for forming an electric / electronic circuit using a metal oxide on a predetermined portion of the substrate. After forming a metal oxide circuit pattern on a substrate by a vapor phase method such as a vapor deposition method, a chemical vapor deposition (CVD) method, a sputtering method, or a coating method using a sol-gel method, unnecessary A method of removing a portion and the like are known.

[0003] For example, Japanese Patent Application Laid-Open No. 7-305027 discloses that a coating agent mainly composed of a photofunctional alkoxysilane and a water-soluble metal nitrate is applied to a substrate.
A method of forming a pattern by irradiating light after drying and dissolving and removing an unirradiated portion with water is disclosed. In the conventional pattern forming method for removing unnecessary portions in a subsequent step, the number of steps is large and complicated, and furthermore, the metal oxide of a portion necessary to use an acid, an alkali or the like to remove unnecessary portions is used. There is a problem that the film is also eroded.

The present inventors have disclosed in Japanese Patent Application Laid-Open No. 2000-14779.
As shown in FIG. 2, a hydrophobic film forming step of forming a film having a photosensitive hydrophobic group on the substrate, and irradiating the hydrophobic film formed on the substrate in the hydrophobic film forming step with light to form a hydrophilic film. Pattern forming step of forming a hydrophilic pattern, and metal oxide depositing a metal oxide through an acid solution containing a fluorine-containing metal compound on the hydrophilic pattern formed on the coating by the hydrophilic pattern forming step A pattern forming method including an object precipitation step has been previously proposed.

Further, the present applicant has previously proposed a method for making the surface of an article highly hydrophilic by the photoexciting action of a semiconductor photocatalyst (WO 96/29375). According to this method, the surface of the article is coated with a coating of a semiconductor photocatalyst such as titanium oxide anatase. When the photocatalyst coating made of anatase-type titanium oxide is irradiated with ultraviolet rays to excite the photocatalyst with sufficient illuminance for a sufficient time, the surface of the photocatalytic coating becomes highly advanced so that the contact angle with water becomes about 0 degrees. It is made hydrophilic.

The photocatalytic coating which can be made highly hydrophilic as described above can be applied to various articles for various purposes such as antifogging, purification by rainfall, purification by washing, promotion of drying, and the like. For example, when a transparent article such as a windshield of a vehicle, a door mirror, a window glass of a building, a lens of an eyeglass, or a mirror is coated with a photocatalytic coating, the surface of the coating is highly hydrophilized with photoexcitation of the photocatalyst, and the As a result, the article is prevented from fogging due to condensed moisture or steam. Alternatively, when an article of a building placed outdoors is covered with a photocatalytic coating, it may be used to remove urban dust, combustion products such as carbon black contained in exhaust gas from automobiles, etc., oils and fats, and hydrophobic components such as sealant eluting components. Both the water-soluble contaminants and the inorganic clay-based contaminants do not easily adhere, and even if they adhere, they are easily washed away by rainfall or water washing, and the surface is purified.

[0007] In these photocatalysts for hydrophilization,
Tissue control, such as unevenness of the surface, is very important. For example, when the surface roughness is increased by pattern formation, the hydrophilic surface changes more hydrophilic due to the effect of increasing the surface area. These theoretical analyzes were performed by Wenzel et al.

[0008] Further, by combining the pattern formation and the hydrophilic use (change in wettability), it becomes possible to apply the present invention to printing and the like. Further, the formed photocatalyst pattern is locally hydrophilized by light irradiation, and by moving the irradiation place to move the hydrophilizing part, the droplet can be moved. It is feasible.

[0009] In addition to the photocatalyst utilizing the function of decomposing organic substances, not only for the above-mentioned hydrophilization application, but also by increasing the surface area of the photocatalyst, which is the working surface of decomposition of organic substances, and by forming a fine pattern, it is possible to improve the rate of decomposing organic substances, It is expected to improve the molecular adsorption function.

[0010]

However, the method disclosed in Japanese Patent Application Laid-Open No. 2000-147792, which was proposed by the present inventors, also involves metal oxide precipitation of a metal oxide via an acid solution containing a fluorine-containing metal compound. Since the metal oxide is deposited not only on the hydrophilic pattern but also on the hydrophobic part because of the inclusion of the substance deposition step, the pattern is removed by peeling off the thin film of the hydrophobic part by ultrasonic treatment or the like in the subsequent step. Therefore, there is a problem that the pattern resolution is low and does not satisfy the standard for practical use of electronic devices.

Further, in controlling the surface texture related to the application of a photocatalyst, a method of forming unevenness on the surface by using sublimation of an additive, a method of mixing an organic substance and an inorganic substance that cause phase separation, and heating after forming a film. A method of controlling the surface structure by burning off organic matter by the method has been proposed, but the method using sublimation greatly limits the raw materials, and the method using burning off is not only easy to treat, Substrates are limited to those having heat resistance such as glass, and application to various substrates has been difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to perform fine patterning of a metal oxide directly on a substrate by a normal temperature process or a process at a relatively low temperature. And a high-density, high-integration various electronic device, and a high-performance optical element by using the pattern forming method that enables a higher pattern resolution than before. And providing the photocatalytic member to the market at low cost.

[0013]

Means for Solving the Problems In order to solve the above problems,
The pattern forming method of the present invention includes a hydrophobic film forming step of forming a film having a photosensitive hydrophobic group on a substrate, and irradiating the hydrophobic film formed on the substrate by the hydrophobic film forming step with light. After performing a hydrophilic pattern forming step of forming a hydrophilic pattern, a metal oxide deposition method for improving the pattern resolution, in particular, the substrate on which the hydrophilic pattern is formed is a hydrolyzable metal oxide precursor The method is characterized in that a step of depositing a metal oxide on the hydrophilic pattern by placing the element in a body atmosphere is employed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The components of the present invention will be described below. The “substrate” of the present invention includes, in addition to a semiconductor substrate made of silicon (Si), metals, ceramics, glass,
Various materials such as carbon, plastics, wood, stone, cement, concrete, and combinations thereof, such as painted plates and laminated plates, which are vulnerable to high temperatures, can be appropriately selected and are not particularly limited. In the present invention, since the processing is performed at room temperature or at a relatively low temperature, material selection in such a wide range becomes possible.

The plastic substrate to which the present invention can be applied includes acrylic resin, polystyrene, ABS, polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide resin, polyvinyl chloride resin, polycarbonate resin, polyphenylene sulfide. Resin, polyphenylene ether resin, polyimide resin, cellulose resin, and the like.

As the light source used in the “hydrophilic pattern forming step” of the present invention, various light sources can be applied, and for example, a mercury lamp, a xenon lamp, an excimer lamp, a pulsed laser or the like can be used. Since the irradiation time is determined depending on the output of the light source to be used, it may be appropriately selected according to the light source. In particular, in order to change the hydrophobic coating to hydrophilic,
It is effective to use ultraviolet light, and it is effective to select the type of light source and the irradiation time on the assumption that ultraviolet light is used.

As the film formed by the "hydrophobic film forming step" of the present invention, a silane derivative is preferably used. The “silane derivative” has a hydrophobic group at the terminal opposite to the silane group.

The silane group of the “silane derivative” of the present invention is preferably a silane group capable of forming a self-assembled film by hydrolyzing on the substrate surface.
3, -SiHCl2, -SiH2Cl, -SiCH3
Cl2, -Si (CH3) 2Cl and the like are mentioned as preferable ones. Further, the linear length between the silane group and the terminal group of the “silane derivative” is-(CH2) n-
Is preferably 4 or more. When n is less than 4, the hydrophobicity of the silane derivative as a whole molecule may be insufficient. The “silane derivative” includes an aromatic compound and a hydrocarbon compound. More preferably, in the case of aromatic phenyltrichlorosilane or the like, it is useful to form a self-assembled film in which the direction of film formation is uniform.

By simply immersing a substrate such as silicon in an organic solvent in which the molecules of these silane derivatives are dissolved, a monomolecular film of the silane derivative is formed on the substrate surface.

In the present invention, the "hydrophobic group" located at the end of the "silane derivative" reacts with light to react with water or the like in the atmosphere to become a sulfonic acid group or a hydroxyl group, thereby exhibiting hydrophilicity. Preferred are, for example, alkyl groups such as methyl group, ethyl group and propyl group, thioacetoxy group, thiocyano group, acetoxy group, phenyl group and the like.

As the "hydrolyzable metal oxide precursor" of the present invention, those which are hydrolyzed, dehydrated and polycondensed to form metal oxides are preferable. For example, metal alkoxides, chlorides, sulfonates and oxychlorides An object or a mixture of those functional groups can be suitably used.

In particular, precursors of titanium oxide include ethoxides of titanium, alkoxides such as isopropoxide, inorganic titanium compounds such as titanium tetrachloride and titanyl sulfate, and organic and inorganic compounds such as titanium dichlorodiethoxide. Precursors having mixed functional groups can be suitably used.

The “hydrolyzable metal oxide precursor atmosphere” of the present invention is created by immersing the precursor in a solution or exposing the precursor to a vapor-generating gas. be able to. The solvent of the precursor solution can be appropriately prepared depending on the properties of the precursor, and toluene, alcohol, water, a mixed solvent thereof and the like can be suitably used. For the generation of the precursor vapor, a general vapor generation method can be used, and vaporization by heating, vaporization by ultrasonic waves, and the like can be suitably used.

The metal oxide deposited by the pattern forming method of the present invention is often amorphous at low temperatures. By appropriately setting the conditions for metal oxide deposition, it is possible to obtain a crystallized metal oxide even at a low temperature. In addition, when crystallizing a metal oxide obtained in an amorphous state, or when it is desired to further improve the crystallinity of a crystallized substance at a low temperature, a hydrothermal treatment, a hydrothermal treatment, and a heat treatment are performed. And crystallinity can be improved.

According to the pattern forming method of the present invention which is performed through the above steps, it is possible to form a fine pattern of a metal oxide by a normal temperature process at around room temperature or a process at a relatively low temperature. Since metal oxides are deposited only on the hydrophilic part, there is no need to peel off the metal oxide deposited on the hydrophobic part by ultrasonic treatment or the like. A pattern forming method that can be performed can be provided.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic process of a pattern forming method according to the present invention. As shown in the drawing, a hydrophobic film forming step of forming a film having a photosensitive hydrophobic group on a substrate, and irradiating the hydrophobic film formed on the substrate by the hydrophobic film forming step with light to obtain a hydrophilic film. After performing the hydrophilic pattern forming step of forming the pattern of the above, the metal oxide is deposited on the hydrophilic pattern by placing the substrate on which the hydrophilic pattern is formed in an atmosphere of a hydrolyzable metal oxide precursor. And the step of causing

First, a “hydrophobic film forming step” (FIG. 1)
In (a) → (b)), for example, the surface of a silicon substrate is washed, and this is immersed in a solution in which silane derivative octadecyltrichlorosilane is dissolved in an organic solvent such as toluene. At this time, the surface of the substrate may be oxidized if necessary. The hydrophobic coating formed in this step is
It is desirable that the silane derivative is covalently bonded to the substrate at the terminal silane group, and it is preferable that the substrate be a coating of several molecular layers or less, more preferably a monomolecular layer.

Next, a "hydrophilic pattern forming step" (FIG. 1)
In (c) → (d)), the substrate on which the above-mentioned hydrophobic film is formed is irradiated with light via a photomask having a predetermined pattern. In this case, as long as light can be irradiated to a predetermined portion, the photomask may be brought into close contact with the substrate, or light may be irradiated at a certain distance. As the irradiation light, ultraviolet light is desirable. When the above-mentioned octadecyltrichlorosilane is used, a methyl group (hydrophobic group) on the surface irradiated with irradiation light is transformed into a silanol group (hydrophilic group). As a result, it is possible to produce a hydrophobic / hydrophilic pattern (template) of methyl groups / silanol groups on the surface.

Further, the following “metal oxide deposition step” (FIG. 1)
As (d) → (e)), the substrate on which the pattern has been formed by the above-described hydrophilic pattern forming step is placed in an atmosphere of a hydrolyzable metal oxide precursor, so that the metal oxide is deposited on the hydrophilic pattern. It is to be deposited. For example,
In the case of using titanium dichlorodiethoxide as a precursor, by immersing the patterned substrate in a toluene solution of titanium dichlorodiethoxide for about 30 minutes under a nitrogen atmosphere, a titanium oxide thin film is formed only in the hydrophilic region. Can be formed.

FIG. 2 shows a reaction between titanium dichlorodiethoxide and a silanol group and a growth process of a titanium oxide thin film. First, chlorine in titanium dichlorodiethoxide reacts with water molecules to cause hydrolysis, resulting in Ti-OH. This hydroxyl group causes dehydration condensation with the silanol group, and forms a covalent bond of Ti—O—Si to form a strong bond. After that, the remaining ethoxy groups react with water molecules to form Ti
-OH, which reacts with other titanium dichlorodiethoxide to cause dehydration polycondensation, thereby forming a thin film of titanium oxide.

At this time, since the hydrophobic portion does not react with Ti-OH, a titanium oxide thin film is formed only on the hydrophilic portion. As a result, a fine titanium oxide pattern can be formed. Similarly, when another hydrolyzable metal oxide precursor is used, a metal oxide thin film is formed only on the hydrophilic portion, so that a fine metal oxide pattern can be formed.

The atmosphere of the hydrolyzable metal oxide precursor is
When immersing the precursor in a solution, the concentration of the precursor in the solution is preferably about 0.01 mol / L to 1 mol / L. When the thickness is less than 0.01 mol / L, the deposition rate of the metal oxide is slow, which is disadvantageous in terms of productivity.In addition, it is difficult to form the metal oxide on all of the hydrophilic portions, and defects are reduced. Easy to occur. If the concentration is higher than 1 mol / L, deposition of metal oxides on the hydrophobic part is likely to occur, and the resolution of the pattern deteriorates.

In order to further improve the resolution of the pattern, it is desirable to hold the substrate on which the hydrophilic pattern is formed, instead of sinking it at the bottom of the solution, floating it in the middle of the solution. Also, instead of turning the pattern forming part upward,
It is desirable to hold vertically or downward. By holding in this manner, it is possible to prevent the precursor from being polycondensed by a self-reaction and from being precipitated by aggregation to adhere to the pattern forming surface, and the pattern resolution is improved. .

The immersion time of the substrate may be determined according to the desired thickness of the metal oxide to be deposited. The thickness of the deposited metal oxide depends on the metal species, the concentration of the metal oxide precursor, the temperature, and the like, and the longer the deposition time, the greater the thickness. Therefore, the immersion time of the substrate may be adjusted in consideration of these conditions, and is preferably 30 minutes.
It is good to soak for 2 to 2 hours.

The patterned metal oxide is
Appropriate heat treatment (simple heat treatment, hot water treatment, hydrothermal treatment) is performed as necessary. For example, when titanium oxide is formed as a metal oxide, amorphous titanium oxide is formed under normal conditions. Although it can be applied to electronic devices such as capacitors and MOSFETs as it is, it is also possible to strengthen the photocatalytic function by heating to 400 ° C. or higher to crystallize and change to anatase type titanium oxide.

In the process of depositing the metal oxide, the type of metal is not limited to one type. For example, it is possible to precipitate barium titanate, which is a composite oxide, by selecting titanium and barium as metal species and performing a precipitation process in the presence of their precursors. Furthermore,
By appropriately controlling the concentration of different metal oxide precursors, or by depositing one first and then adding another precursor and continuing the deposition process, another metal It is also possible to create a state in which seeds are added, to form a mixed structure in which different metal oxides are separately deposited, or to form a layered structure in which another metal oxide is deposited on one kind of metal oxide. It is possible.

The electronic device of the present invention is a DRAM
From element devices such as capacitors and MOSFETs,
A high-density IC circuit or the like using these can be realized. In particular, alumina, tantalum oxide,
When titanium oxide is used, the relative dielectric constant is higher than that of conventionally used silicon dioxide, and alumina (8.1) and tantalum oxide (relative to silicon dioxide (relative dielectric constant: about 3.5)) are used. 27), since it becomes titanium oxide (80),
In order to realize the same capacitance, the area of the element can be reduced, so that downsizing of the device can be expected. In addition, when the element area is the same, the thickness of the metal oxide can be increased, so that there is an advantage that the thickness control during element formation is facilitated. Further, by depositing a metal oxide having piezoelectricity such as barium titanate or zinc oxide in an appropriate pattern, it is possible to realize a SAW device or the like.

As the optical element of the present invention, a diffraction grating, a photonic crystal and the like can be realized. In particular, when titanium oxide is used as the metal oxide, downsizing of these elements can be expected because titanium oxide is a high refractive index material.

[0040] The photocatalyst used in the photocatalytic member of the present invention, the irradiation of the photoelectron - hole pairs are generated, in the electrons and holes are directly or superoxide ion (O ₂ ^-) and water It acts on organic substances, water, and metal ions on the surface via active oxygen such as acid radicals (OH) to have properties such as oxidative decomposition of organic substances, photolysis of water, and reduction of metal ions. . Applications of this function include an antibacterial surface that kills microorganisms and molds, a deodorizing surface that decomposes surrounding odors, and a photodecomposition surface that decomposes water into hydrogen gas and oxygen gas just by irradiating light. .

Another function of the photocatalyst is the property that electron-hole pairs are generated by light irradiation, and these change the surface wettability by inducing a structural change of the titanium oxide material itself. . As an application of the superhydrophilic function, it is possible to realize an antifogging function surface for preventing surface fogging and water droplet formation, and an easy-cleaning surface capable of removing surface dirt with water only.

As the photocatalytic metal oxide which can be used for these photocatalytic members, zinc oxide, tin oxide, tungsten oxide, bismuth oxide, iron oxide, strontium titanate, titanium oxide and the like can be used. In particular, it is most preferable to use titanium oxide. Since titanium oxide is chemically stable and has a particularly strong photocatalytic activity, it is the most frequently used material in both photocatalytic decomposition applications and superhydrophilic applications.

When a metal oxide formed on a semiconductor by the pattern forming method of the present invention is used as an electronic device, if the metal oxide is a photocatalytic metal oxide, the metal of the electrode is changed. It is possible to obtain a combined effect that the formation is facilitated.

That is, a MOS structure (Me) in which a metal oxide is formed on a silicon substrate and a metal electrode is formed thereon
tal-Oxide-Semiconductor, metal-oxide-semiconductor) is an important element element.
An OSFET (MOS structure field effect transistor) is one of the core units of various semiconductor devices.
In manufacturing this structure, it is necessary not only to form a fine pattern of a metal oxide on a semiconductor substrate, but also to accurately form a pattern of a metal electrode on the metal oxide. Conventionally, in order to accurately form the metal electrode, a complicated process requiring masking at the time of forming the electrode was required.

On the other hand, if the metal oxide is a photocatalytic metal oxide, the photocatalyst has a function of reducing and supporting metal ions as described above. An electrode in which a metal that becomes an electrode is reduced and deposited only on the surface of the photocatalytic metal oxide by simply immersing it inside and irradiating the entire surface with light that excites the photocatalyst. Can be easily manufactured.

[0046]

EXAMPLES (Example 1) Sample Preparation According to the Present Invention Using p-type Si (100) as a substrate, the substrate is sufficiently washed and then dried. Under a nitrogen atmosphere, the substrate was immersed for 5 minutes in a solution in which octadecyltrichlorosilane was mixed at 1 vol% with anhydrous toluene. After taking out the substrate, the substrate was dried at 120 ° C. for 5 minutes to completely evaporate the solvent and promote a chemical bond of octadecyltrichlorosilane to form a hydrophobic film (hydrophobic film forming step).

Next, a photomask having a predetermined pattern is set on the substrate on which the hydrophobic film is formed, and the substrate is irradiated with mercury lamp light (ultraviolet light having a wavelength of 220 to 400 nm) for 2 hours. As a result, only the predetermined pattern portion of the hydrophobic film irradiated with ultraviolet light became hydrophilic due to the formation of the silanol group, and a hydrophilic pattern was formed on the substrate (hydrophilic pattern forming step). At this time, the contact angle of water of the hydrophobic portion not irradiated with ultraviolet light was 96 °, whereas the contact angle of the hydrophilic portion irradiated with ultraviolet light was 5 ° or less, and sufficient hydrophilicity was not obtained. confirmed.

Next, titanium dichlorodiethoxide was added in an amount of 0.1%.
A solution dissolved in toluene was prepared so as to be 1 mol%, and the substrate on which the hydrophilic pattern was formed was immersed in this solution for 30 minutes under a nitrogen atmosphere (metal oxide deposition step).
Thereafter, the substrate was taken out, washed with toluene, and dried naturally to obtain a sample # 1. At this time, a blue thin film was formed in the portion that was made hydrophilic by ultraviolet irradiation in the pattern forming step, but no thin film was formed in the hydrophobic portion.

(Comparative Example 1) In the metal oxide deposition step of Example 1, a sample was prepared by the following steps instead of the present invention. 0.005 mol of (NH4) 2 Ti
F6 and 0.015 mol of boric acid in 50 ml each
In distilled water and heated to 50 ° C. Then, after mixing the two kinds of solutions, an appropriate amount of HCl was added for pH adjustment. Then, immerse the substrate in this mixed solution,
Place the ultrasonic vibrator on the outside of the container,
The substrate was irradiated with ultrasonic waves (frequency: 47 kHz, output: 70 W) for about 2 hours to deposit a metal oxide while maintaining the temperature. Thereafter, the substrate was taken out, washed with distilled water, and air-dried to prepare Sample # 2.

Example 2 Evaluation of Pattern Resolution FIG. 3 shows an electron microscope (S-30 manufactured by Hitachi, Ltd.) of sample # 1.
00N). As a pretreatment for observation, ultrasonic cleaning in acetone was performed, but no thin film was peeled off, and it was confirmed that the metal oxide thin film formed according to the present invention was strongly bonded to the substrate. . FIG. 2 shows that titanium oxide having a square pattern of about 20 μm square is precisely formed and has almost no defects or deposits. 1 at regular intervals to evaluate pattern resolution
When the line width of five points was measured, the average value was 23.3 μm,
The standard deviation was 0.5 μm and the variation was 2.1%. Similarly, when sample # 2 was evaluated, the variation was 28%, indicating that the pattern resolution was greatly improved by the present invention. Since the standard of practical use according to the current electronic device design rules has a variation of 5% or less, it has been found that the pattern formed according to the present invention can be applied to electronic devices.

Example 3 Evaluation of Metal Oxide Deposition Time and Film Thickness Sample # 3 was formed by forming a hydrophilic pattern in the same manner as in Example 1 and changing the immersion time to 5 minutes in the metal oxide deposition step. I got Samples # 1 and # 3 using an atomic force microscope (Nanoscope E manufactured by Digital Equipment Corporation)
The film thicknesses of 27.4 μm and 6.
It was 9 μm. This indicates that the film thickness can be adjusted only by changing the immersion time in the metal deposition step.

Example 4 Composition Analysis Sample # 1 obtained in Example 1 was subjected to composition analysis by XPS (X-ray photoelectron spectroscopy VG Scientific Ltd., ESCALAB210).
In the analysis of the portion where the hydrophilic pattern was formed and the titanium oxide was deposited, a binding energy of 458.5 eV in the 2p orbit of Ti was obtained. This is made of metallic titanium (45
4.0 eV), TiC (454.6 eV), TiO (4
55.0 eV), TiN (455.7 eV), Ti ₂ O ₃
(456.7 eV) and different from TiO ₂ (458.4-
458.7 eV), indicating that titanium dioxide (TiO ₂ ) was formed here.
The presence of Ti was not confirmed in the hydrophobic part, and this also indicated that the metal oxide was deposited only in the hydrophilic part.

(Example 5) Examination of heat treatment Sample # 1 obtained in Example 1 was subjected to a heat treatment at a predetermined temperature, and an X-ray diffractometer (RU-20 manufactured by Rigaku Denki) was used.
FIG. 4 shows the result of the crystal identification according to 0). In the state where the heat treatment was not performed (FIG. 4-a), no clear peak appeared and the film was amorphous. As this sample was heated, the peak of anatase-type titanium oxide began to appear at 400 ° C. heating (FIG. 4-e), and the crystallinity was improved as the heating temperature was increased. The peak of anatase type titanium oxide was observed. When this sample was further heated, it was also observed that at 1000 ° C., transformation to rutile-type titanium oxide occurred. When the sample heated at 600 ° C. was subjected to the same electron microscopic observation and pattern resolution evaluation as in Example 2, no cracks or defects were observed, and the pattern variation did not change.

Example 6 Preparation of Sample by Gas Phase Method Using p-type Si (100) as a substrate, the same steps as in Example 1 were performed up to the pattern formation step. Next, a solution prepared by dissolving titanium dichlorodiethoxide in toluene so as to have a concentration of 0.1 mol% is prepared, and the substrate on which the titanium dichloroethoxide solution and the hydrophilic pattern are formed is heated to 90 ° C. in a sealed nitrogen atmosphere. Then, the substrate was left in a gaseous atmosphere of titanium dichloroethoxide for 2 hours.
(Metal oxide deposition step). Thereafter, the substrate was taken out, washed with toluene, and dried naturally to obtain a sample # 4. At this time, an amorphous titanium oxide thin film was formed only in the portion that was made hydrophilic by ultraviolet irradiation in the pattern forming step. FIG. 5 shows an electron micrograph of Sample # 4. As in Example 5, this thin film also undergoes a phase transition to an anatase phase upon heating at 400 ° C. and a rutile phase upon heating at 1000 ° C., and no deterioration in pattern resolution was observed at that time.

(Example 7) Evaluation of photocatalytic hydrophilicity Sample # 1 obtained in Example 1 was heated at 500 ° C.
Sample # 5 was obtained by heating for an hour. In FIG.
The illuminance of 1 mW /
The change with time of the contact angle with water when irradiated with ultraviolet rays of cm 2 is shown. Sample # 1 is amorphous as described in Example 5, but has a contact angle with water of about 8 by irradiation with ultraviolet light for 7 hours.
It decreased from 0 ° to about 60 °, indicating weak hydrophilicity. Sample # 5 showed the crystal structure of anatase from the data of X-ray diffraction, and the contact angle with water was reduced from about 40 ° to about 5 ° by irradiation of ultraviolet light for 1 hour, showing strong hydrophilizing properties. .

The pattern forming method according to the present invention comprises a hydrophobic film forming step of forming a film having a photosensitive hydrophobic group on a substrate, and a hydrophobic film formed on the substrate by the hydrophobic film forming step. A hydrophilic pattern forming step of irradiating the coating with light to form a hydrophilic pattern, and placing the substrate on which the hydrophilic pattern is formed in an atmosphere of a hydrolyzable metal oxide precursor to form a hydrophilic pattern on the hydrophilic pattern. A metal oxide deposition step of depositing a metal oxide on the substrate. Therefore, it is possible to form a fine-shaped pattern using a metal oxide in a room temperature process near room temperature or a process at a relatively low temperature. There is no need to remove the metal oxide deposited on the part by ultrasonic treatment or the like, and a pattern formation method that meets the criteria for practical use of electronic devices and is inexpensive and easy to perform is provided, and is extremely useful in industry. It is a high invention.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic process of forming a pattern according to the present invention.

FIG. 2 is a diagram schematically showing a chemical reaction in a metal deposition step according to the present invention.

FIG. 3 is a surface observation diagram of Sample # 1 according to Example 2.

FIG. 4 is an X-ray diffraction chart when Sample # 1 according to Example 5 was heated.

FIG. 5 is a surface observation diagram of sample # 4 according to Example 6.

FIG. 6 is a diagram illustrating a change in contact angle of Samples # 1 and # 5 according to Example 7 due to ultraviolet irradiation.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/312 H01L 21/316 U 21/316 21/30 502R (72) Inventor Yoshitake Masuda Nagoya, Aichi 2-44, Wakamizu 2-chome, Chikusa-ku, Iwakami 4-44 F term (reference) 2H025 AA02 AB16 AB17 AB20 AC01 AD01 BF30 BH03 FA39 2H096 AA25 AA30 BA09 BA20 EA02 HA02 HA30 JA04 LA30 4G069 AA03 AA08 BA04A BA04B BA08A DA06 FB39 5F058 AA07 AC03 AC07 AF04 AG01 AH01 BA11 BC03 BF46 BH01 BH17

Claims (23)

[Claims] 1. A hydrophobic film forming step of forming a film having a photosensitive hydrophobic group on a substrate, and irradiating the hydrophobic film formed on the substrate by the hydrophobic film forming step with light to obtain a hydrophilic film. A hydrophilic pattern forming step of forming a pattern of
Placing the substrate having the hydrophilic pattern formed thereon in an atmosphere of a hydrolyzable metal oxide precursor, thereby depositing a metal oxide on the hydrophilic pattern. Forming method. 2. The pattern forming method according to claim 1, wherein the placing in the atmosphere of the hydrolyzable metal oxide precursor is immersion in a hydrolyzable metal oxide precursor solution. 3. The pattern forming method according to claim 1, wherein the exposure to the atmosphere of the hydrolyzable metal oxide precursor is exposure to a vapor containing the hydrolyzable metal oxide precursor. Method. 4. The pattern forming method according to claim 1, wherein the film formed in the hydrophobic film forming step is made of a silane derivative. 5. The photosensitive hydrophobic group of the silane derivative,
Organic alkyl groups, phenyl groups, thioacetoxy groups,
One or two selected from a thiocyano group and an acetoxy group
5. The pattern forming method according to claim 4, wherein the method is at least one kind. 6. The pattern forming method according to claim 1, wherein the light for forming the hydrophilic pattern is ultraviolet light. 7. The pattern forming method according to claim 1, wherein the hydrolyzable metal oxide precursor is a compound of tantalum, aluminum, barium, and zirconium. 8. The pattern according to claim 1, wherein the hydrolyzable metal oxide precursor is a compound of zinc, tin, tungsten, bismuth, iron, and strontium. Forming method. 9. The pattern forming method according to claim 1, wherein the hydrolyzable metal oxide precursor is a titanium compound. 10. The pattern forming method according to claim 9, wherein the compound of titanium is titanium tetraethoxide or titanium monochlorotriethoxide. 11. The pattern forming method according to claim 9, wherein the titanium compound is titanium dichlorodiethoxide, titanium trichloromonoethoxide, or titanium tetrachloride. 12. The pattern according to claim 1, wherein the metal oxide deposited in a hydrophilic pattern is amorphous titanium oxide. Forming method. 13. The metal oxide deposited in the form of a hydrophilic pattern is an anatase-type titanium oxide or a rutile-type titanium oxide.
The pattern forming method according to any one of the first to third aspects. 14. The pattern forming method according to claim 1, wherein an ultrasonic treatment is further performed in the pattern forming method. 15. The pattern forming method according to claim 1, wherein a heat treatment is further performed in the pattern forming method. 16. The pattern forming method according to claim 1, further comprising performing a hydrothermal treatment or a hydrothermal treatment in the pattern forming method. 17. An electronic device, wherein a metal oxide pattern is formed on a substrate by the pattern forming method according to claim 1. Description: 18. An optical element, wherein a metal oxide pattern is formed on a substrate by the pattern forming method according to claim 1. Description: 19. A photocatalytic member, wherein a pattern of a photocatalytic metal oxide is formed on a substrate by the pattern forming method according to claim 1. Description: 20. The electronic device, the optical element, or the photocatalytic member according to claim 17, wherein the substrate is a semiconductor. 21. The electronic device, the optical element, or the photocatalytic member according to claim 20, wherein the semiconductor is silicon. 22. An electronic device, an optical element, or a photocatalytic member according to claim 17, wherein a metal thin film is further formed on the metal oxide. 23. The metal thin film is formed by photocatalytic reduction of metal oxide by immersing the substrate in a solution of a soluble metal salt and irradiating the substrate with light after the pattern is formed according to claim 1. A method for producing an electronic device, an optical element, or a photocatalytic member.