JP5470934B2 - Manufacturing method of fine structure - Google Patents

Description

  The present invention relates to a method for manufacturing a three-dimensional microstructure.

  In recent years, fine structures formed with a specific fine three-dimensional structure pattern have been widely used.

  Applications of fine structures include, for example, semiconductor devices, optical elements, wiring circuits, data storage media (hard disks, optical media, etc.), medical materials, bio devices (biosensors, cell culture substrates, etc.), and precision inspection equipment. Examples include members (inspection probes, sample holding members, etc.), display panels, panel members, energy devices (solar cells, fuel cells, etc.), microchannels, microreactors, MEMS devices, and the like.

  In Patent Document 1, for example, as a thermal field emission device used in an electron beam apparatus such as a scanning electron microscope, a thermal field emission device (FIG. 3) having a multi-layered convex stepped stacked electron emission surface is provided. It is disclosed (see Patent Document 1).

  Patent Document 2 discloses that, for example, in a moth-eye structure provided for antireflection applications, the fine structure pattern is formed into a pointed cone shape (cone, square pyramid, polygonal pyramid, etc.). (See Patent Document 2).

  In order to form such a three-dimensional fine structure, a fine processing technique corresponding to the structure is required.

  For example, Patent Literature 3 discloses a method of forming a three-dimensional structure by repeating lithography and electroforming (see Patent Literature 3).

  A fine structure manufacturing method for forming a fine structure is desired.

Japanese Patent Laid-Open No. 10-228877 JP 2006-038928 A JP 2007-204809 A

  An object of this invention is to provide the manufacturing method of the microstructure which can be performed simply.

The invention according to claim 1 of the present invention includes a step of applying a semi-solid microstructure material to a lower region in an intaglio plate, a step of disposing a base provided with a protrusion and an intaglio, and a base and a concave plate to approach includes the step of contacting a microstructure material of the protrusion and the intaglio substrate and a step of fixing the protruding portion of the substrate and microstructure material and microstructure material Is a gel, and the microstructure material is an oleophilic material, the surface of the substrate exhibits oleophilicity, and the surface in the intaglio plate exhibits oleophobicity. This is a manufacturing method.

The invention according to claim 2 of the present invention is the method for manufacturing a microstructure according to claim 1, wherein the microstructure material includes a gel-like dispersant. It is what.

The invention according to claim 3 of the present invention is the method for manufacturing a fine structure according to claim 1 or 2 , wherein the intaglio has flexibility. Is.

The invention according to claim 4 of the present invention is the method of manufacturing a microstructure according to any one of claims 1 to 3 , wherein the intaglio is made of a silicon substrate or a quartz substrate. This is a manufacturing method.

Invention of Claim 5 of this invention is a manufacturing method of the microstructure in any one of Claims 1 thru | or 4 , Comprising: The process of apply | coating, the process of arrange | positioning, the process of contacting, The process of fixing And a plurality of times, and the amount of the fine structure material to be filled in the intaglio is successively reduced.

The invention according to claim 6 of the present invention is the method for manufacturing a microstructure according to any one of claims 1 to 5, wherein a semi-solid microstructure material is applied to the intaglio of the intaglio. However, it is a manufacturing method of a fine structure characterized in that a semi-solid fine structure material is applied only to a part of the intaglio.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the fine structure which apply | coats a semi-solid fine structure material to an intaglio, and transfers fine structure material to a base | substrate can be provided. Furthermore, according to the present invention, by making the fine structure material semi-solid, the fine structure material can follow the shape of the intaglio and can produce a three-dimensional structure having a tip corresponding to the shape of the intaglio. .

(A)-(e) is a schematic process drawing which shows the manufacturing method of the intaglio used for the manufacturing method of the microstructure which concerns on embodiment of this invention. (A)-(e) is a schematic process drawing which shows the manufacturing method of the microstructure which concerns on embodiment of this invention. It is an example of the thermal field emission element provided with the laminated film at the front-end | tip, (a) is sectional drawing which shows a thermal field emission element, (b) is a top view which shows a thermal field emission element.

  Hereinafter, a method for manufacturing a microstructure according to an embodiment of the present invention will be described with reference to the drawings. Note that, in the embodiments, the same components are denoted by the same reference numerals, and redundant description among the embodiments is omitted.

  2A to 2E are schematic process diagrams showing a method for manufacturing a microstructure according to an embodiment of the present invention. As shown in FIG. 2 (e), the fine structure formed using the fine structure manufacturing method according to the embodiment of the present invention includes a laminated film 12 on the base 11. The laminated film 12 is formed in a convex staircase shape using a semi-solid material as a microstructure material. Here, the semi-solid state means an elastic and soft (plasticized) substance. Examples of the semisolid state include a gel substance and a thermoplastic elastomer. In order to make the microstructure material semi-solid, the microstructure material itself may be gelled, or a gel-like dispersant may be included in the microstructure material.

<Process of applying fine structure material to intaglio>
First, a fine structure material is applied to the intaglio plate 14 so as to face the substrate 11.

  The intaglio 14 according to the embodiment of the present invention can be appropriately selected depending on the application. The intaglio plate 14 can be processed in advance using a fine processing technique. As the fine processing technique, for example, a lithography method, an etching method, a fine machining method (laser processing, machining processing, grinding processing, or the like) can be used.

  The material of the intaglio 14 can be appropriately selected and used as long as it does not elute into the fine structure material. As the material of the intaglio plate 14, for example, a silicon substrate, a quartz substrate, an aluminum substrate, or the like can be used. In particular, since a silicon substrate or a quartz substrate can be hydrophilic or hydrophobic depending on a processing method for a natural oxide film, the surface energy can be suitably controlled, and the fine structure according to the embodiment of the present invention can be used. It is preferable as a material of the intaglio 14 used in the method for manufacturing the structure.

  Here, in order to improve the releasability of the hydrophilic fine structure material with respect to the intaglio 14, it is preferable to reduce the surface energy of the intaglio 14 surface. The method for reducing the surface energy is not particularly limited. For example, surface treatment with a silane coupling agent such as HMDS (hexamethyldisilazane) on the surface of the intaglio plate 14, hydrophobic treatment with water-repellent plating containing fluorine-based particles, and fine processing technology And surface treatment by forming fine irregularities, and surface treatment by metal plating.

  The intaglio plate 14 may be a molded product produced by a transfer molding method using a processed product obtained by the above-described microfabrication technique as a mother mold. The material of the molded product is not particularly limited, and examples thereof include synthetic resins such as polycarbonate, polystyrene, acrylic resin, and fluorine resin, or silicone resins, biocompatible resins such as maltose, polylactic acid, and dextran.

  The upper surface shape of the intaglio 14 is a design matter and is not particularly limited. The top surface shape may be, for example, a pattern such as a quadrangle, a triangle, or a circle. One pattern of the intaglio plate 14 may be arranged in the plate, or a plurality of patterns may be arranged. When a plurality of patterns are arranged on the intaglio, the patterns of the intaglio 14 can be arranged in an array.

  The cross-sectional shape of the intaglio 14 is a design matter and is not particularly limited. Moreover, each dimension regarding the upper surface shape and cross-sectional shape of the intaglio 14 is a design matter, and is not specifically limited.

  In addition to being fluid so that the fine structure material can be applied to the intaglio plate 14, the fine structure material can be transferred at the time of transfer from the intaglio plate 14 to the substrate 11. It is preferably a fluid or gel (semi-solid). The form of the fine structure material can be appropriately selected according to the use of the fine structure. In addition, a solvent may be appropriately added to the microstructure material depending on the polarity. Generally, it is known that a polar material is easily dispersed in a polar solvent (such as an aqueous system), and a nonpolar material is easily dispersed in a nonpolar solvent (a solvent system).

  Examples of polar solvents include ketones such as acetone, MEK and MIBK, alcohols such as methyl alcohol, ethyl alcohol and 2-propanol, esters such as ethyl acetate and n-butyl acetate, and pure water. Can be mentioned.

  Examples of the nonpolar solvent include aromatic hydrocarbons such as isooctane, cyclohexane, and isophorone, toluene, xylene, mesitylene, 1,2,3,4-tetrahydronaphthalene (tetralin), n-hexane, and n-decane. Aliphatic hydrocarbons can be mentioned.

  The fluidity of the microstructure material is not particularly limited, but it is desirable to use a semi-solid microstructure material. Since the fine structure material is gelled, no transfer failure due to the surface tension of the fine structure material occurs, so that the transfer process to the substrate can be suitably performed. When the fine structure material is gelled, the fine structure material dispersed in various solvents is mixed with a gelling agent.

  Examples of the gelling agent for making the microstructure material into a gel include gelatin, pectin, agar, carrageenan, sodium carboxymethylcellulose, xanthan gum, guar gum and the like.

  In the step of applying the fine structure material to the intaglio 14, it is necessary to fill the intaglio 14 with a desired fine structure material. In particular, a gelled microstructure material is desirably in a state having fluidity at the time of application. For this reason, by heating the microstructure material in advance at the time of application, fluidity can be imparted to the gelled microstructure material, and the application process can be suitably performed.

  Moreover, it does not specifically limit as a method of apply | coating a microstructure material, The thing optimal for various high viscosity liquids can be used suitably. For example, specifically, a spin coating method, a spray method, a dip method, a droplet method, or the like can be used.

  After the fine structure material is applied, it can be gelled by cooling the fine structure material in the intaglio 14. The hydrophilic gel is held in the hydrophobic intaglio 14 in a state of high releasability. Thereby, the subsequent transfer process to the substrate 11 can be suitably performed.

  Therefore, when the transfer of the fine structure material to the substrate 11 is considered, the surface of the substrate 11 is preferably hydrophilic. The method for treating the surface of the substrate 11 is not particularly limited, and a known treatment method can be appropriately used according to desired surface characteristics. At this time, for example, ozone irradiation, electromagnetic wave irradiation such as ultraviolet rays or X-rays, electron beam irradiation, plasma irradiation, addition of a property modifying substance to the surface, addition of a photocatalyst, etc. can be suitably used as the surface treatment method. For example, as a patterning method, a method of selectively performing a surface treatment using a metal mask may be used.

  The substrate 11 can be appropriately selected and used depending on the application. Further, it may be processed in advance using a fine processing technique. For example, as a fine processing technique, a lithography method, an etching method, a fine machining method (laser processing, machining processing, grinding processing, or the like) may be used.

<Step of placing the base and the intaglio plate facing each other>
In the step of arranging the base 11 and the intaglio 14 to face each other, it is desirable to accurately match the positions of the base 11 and the intaglio 14. The alignment method is not particularly limited, and examples thereof include a method of positioning after positioning marks are respectively arranged, a method of using a positioning jig, and the like.

  Further, in the step of arranging the base 11 and the intaglio 14 so as to face each other, the base 11 provided with projections arranged in an array and the intaglio 14 arranged in an array may be used. In this case, by changing the amount of the fine structure material to be applied to the pattern of the plurality of intaglios 14 arranged in an array, the fine structure material is selectively applied to only a part of the protrusions between the arrays. Can be applied. Thereby, an arrayed three-dimensional structure having a distribution in the height of the protrusions arranged in an array can be formed. Such a three-dimensional structure can be used as an antireflection body.

<Step of contacting the substrate with the microstructure material>
Next, either or both of them are brought close to the distance at which the protruding portion of the substrate 11 and the fine structure material come into contact with each other, thereby fixing the fine structure material. Further, when it is desired to enhance the fixing of the microstructure material, it is desirable to use the intaglio plate 14 having flexibility (flexibility). If a molded product or the like produced by the above-described transfer molding method is used, the intaglio 14 has flexibility even against contact with the base 11, so that the base 11 and the fine structure can be formed at a high pressure while suppressing destruction of the base 11. Body material can be contacted.

<Step of fixing substrate and microstructure material>
In the step of fixing the substrate 11 and the fine structure material, the fixing method can be selected according to the fine structure material used. For example, the solvent may be volatilized by drying, or the solvent may be volatilized by plasma treatment depending on the plasma resistance of the fine structure material.

  Further, in the method for manufacturing a fine structure according to the embodiment of the present invention, the above-described steps may be sequentially repeated a plurality of times. By repeating each step a plurality of times, the laminated film 12 in which the fine structure material is laminated can be formed.

  Further, when each step is repeated a plurality of times, it is preferable to sequentially reduce the amount of the fine structure material applied to the planographic plate every time the step is repeated. At this time, the convex step-like laminated film 12 can be formed, and a cone-shaped microstructure can be formed.

  The manufacturing method of the microstructure according to the embodiment of the present invention can be used in a wide range of fields. In particular, it is suitable for use in manufacturing a thermionic emission device. The thermionic emission device has a problem in that a high electric field concentrates on the tip of the emitter during use, so that the tip of the emitter disappears and the lifetime of the thermal field emission device is exhausted. For this reason, it has been proposed to stack the electron emission surface on the tip of the emitter (FIG. 3 (a) sectional view, (b) top view). If the manufacturing method of the microstructure according to the embodiment of the present invention is used, a thermionic emission device in which the emitter tip (base 11) is the laminated film 12 can be particularly preferably manufactured.

  In the method for manufacturing a microstructure according to the embodiment of the present invention, the hydrophobicity and oleophobicity may be surfaces having the following levels. As an example, the extent range is specifically shown.

  Hydrophobic means that the contact angle with water is 110 ° or more in the case of water, preferably 150 ° or more in the case of water, and the falling angle of water (a single water droplet of an amount of 0.5 ml falls on the inner wall surface of the pipe). In this case, it means a surface having an inclination angle required for water) of 10 ° or less, preferably 5 ° or less for water.

  The oleophobicity means that the contact angle with oil (for example, gasoline) is 90 ° or more in the case of oil, preferably 110 ° or more in the case of oil, and the falling angle of oil (1 in the amount of 0.5 ml on the inner wall surface of the pipe). It means a surface having an inclination angle required for the individual oil droplets to fall down to 20 ° or less, preferably 10 ° or less in the case of oil.

Hereinafter, as an example, a manufacturing method of a thermal field emission device in which the tip of an emitter (base 11) is formed of a laminated film 12 of ZrO ₂ (zirconia) using a manufacturing method of a fine structure will be described with reference to FIG. ) To (f) and FIGS. 2 (a) to 2 (e).

  First, a resin intaglio plate 14 (see FIG. 1 (f)) showing hydrophobicity was produced. As shown in FIG. 1A, a photomask 13 having a diamond-shaped island-shaped light-shielding portion 4 with a diagonal of 100 μm formed on the exposure light transmitting portion 3 was prepared for producing the intaglio 14.

  Next, as shown in FIG. 1B, a resist layer 6 having a thickness of 300 μm is formed on a 4-inch silicon substrate 5 by spin coating using SU-8 resist manufactured by Microchem. Formed.

  Next, as shown in FIG. 1C, a photomask 13 was brought into contact with the silicon substrate 5 and the resist layer 6 after spin coating.

Next, as shown in FIG. 1D, the contacted photomask 13 and resist layer 6 were exposed. At the time of exposure, a substrate (not shown) to be exposed was set on a stage whose tilt angle can be controlled, the substrate was tilted 15 ° in the positive direction, and exposure was performed with a high-pressure mercury lamp. Next, as shown in FIG. 1 (e), when the exposure with the exposure light (forward direction) 7 was completed, the exposure was performed with an inclination of 15 ° in the opposite direction. At this time, the exposure amounts in the forward direction 7 and the opposite direction 8 were integrated to obtain an exposure amount of 2000 mJ / cm ² . A V-shaped latent image was obtained at the exposed portion of the 300 μm resist layer 6 by incident light and reflected light from the forward direction 7 and the opposite direction 8.

  Next, development was performed. As a developer, SU-8 Developer manufactured by Microchem Co., Ltd. was used, and development was performed while rocking with a metal bat. As a result, an intaglio plate 14 made of resin was obtained. As a result of measuring the contact angle, it was confirmed that the contact angle with water was 120 ° and it was hydrophobic.

  Next, as shown in FIG.1 (f), in order to obtain the flexible intaglio 14 peculiar to resin, the silicon substrate 5 of 4 inches was melt | dissolved with potassium hydroxide.

  Next, as shown in FIG. 2A, a fine structure material (single layer film 10) was prepared and filled in the intaglio plate 14 by a droplet method. Zirconium was used as the microstructure material. Zirconium is soluble in some polar solvents, and a gelatinized microstructure material was prepared by dispersing zirconium nitrate in the solution and mixing it with an aqueous gelatin solution.

  A dispenser 9 was used to fill the intaglio 14 with the fine structure material. As the dispenser 9, MD-K-140 manufactured by Microdrop having a nozzle diameter of 50 μm was used. MD-K-140 is a mechanism that causes the coating liquid to pop out with pressure from a piezoelectric element.

  Accordingly, the pipe of the dispenser 9 is heated to 90 ° C., so that the fine structure material has fluidity. As a result, a fine structure material having a diameter of about 50 μm was applied from the head of the dispenser 9, and was retained while maintaining the diameter after being filled and cooled in the intaglio plate 14.

  Next, as shown in FIG. 2 (b), the tip of the emitter (substrate 11) of the thermal field emission electron gun was aligned with the intaglio 14.

  Next, as shown in FIG. 2 (c), the tip of the emitter (base 11) of the thermal field emission electron gun and the intaglio 14 were brought close to each other, and the droplets in the intaglio 14 were brought into contact with each other. In order to ensure transfer, the tip of the emitter was pressed against the intaglio plate 14 with high pressure, and as a result, the fine structure material could be transferred to the tip of the emitter. Since the flexible intaglio plate 14 was used, the tip of the emitter was not broken.

After the transfer, as shown in FIG. 2 (d), a gelled zirconium solution is adhered to the tip of the emitter of the thermal field emission electron gun, and ZrO ₂ having a diameter of 50 μm and a film thickness of 5 nm is obtained through a drying process by heating. A monolayer film 10 of (zirconia) could be obtained.

  Next, the discharge conditions by the dispenser 9 were changed to discharge onto the intaglio plate 14, and after landing, a droplet having a diameter of 45 μm was discharged.

Next, as shown in FIG. 2E, a transfer process and a drying process are performed again, and a ZrO ₂ film having a diameter of 45 μm and a film thickness of 5 nm is formed on the ZrO ₂ single-layer film 10 having a diameter of 50 μm and a film thickness of 5 nm. A laminated film 12 in which the single-layer films 10 were stacked was obtained.

  From the above, a convex stepped stacked electron emission surface having a tip width of 5 μm and a film thickness of 50 nm could be formed with respect to the emitter tip of the thermal field emission electron gun. The use period of the thermal field emission device was about 10,000 hours, and it was confirmed that the lifetime could be longer than before.

  The method for producing a fine structure of the present invention is expected to be used in a wide range of fields in which it is required to form a fine structure. Examples of the fine structures include semiconductor devices, optical elements, wiring circuits, data storage media (hard disks, optical media, etc.), medical members, bio devices (biosensors, cell culture substrates, etc.), precision inspection equipment members ( Inspection probes, sample holding members, etc.), display panels, panel members, energy devices (solar cells, fuel cells, etc.), microchannels, microreactors, MEMS devices, etc. can be manufactured.

DESCRIPTION OF SYMBOLS 3 ... Exposure light transmission part 4 ... Island-shaped light-shielding part 5 ... Substrate 6 ... Resist layer 7 ... Exposure light (positive direction)
8 ... Exposure light (opposite direction)
DESCRIPTION OF SYMBOLS 9 ... Dispenser 10 ... Single layer film 11 ... Base | substrate 12 ... Laminated film 13 ... Photomask 14 ... Intaglio 21 ... Emitter 22 ... Laminated film

Claims (6)

Applying a semi-solid microstructure material to the lower region of the intaglio intaglio ,
A step of disposing the base provided with the protruding portion and the intaglio, opposite to each other;
To approximate the concave plate and the substrate, a step of contacting the projecting portion of the substrate and the microstructure material in said intaglio,
Fixing the protrusions of the base and the microstructure material , and
The microstructure material is in a gel form, and
The microstructure material is an oleophilic material, the surface of the base body is oleophilic, and the surface in the intaglio of the intaglio is oleophobic . Production method. It is a manufacturing method of the fine structure according to claim 1,
The method for manufacturing a microstructure, wherein the microstructure material includes a gel-like dispersant. It is a manufacturing method of the fine structure according to claim 1 or 2 ,
The method for manufacturing a fine structure, wherein the intaglio has flexibility. A method for manufacturing the microstructure according to any one of claims 1 to 3 ,
The method for manufacturing a fine structure, wherein the intaglio is made of a silicon substrate or a quartz substrate. A method for producing a microstructure according to any one of claims 1 to 4 ,
The step of applying, the step of placing, the step of contacting, and the step of fixing are repeated a plurality of times,
A method for manufacturing a microstructure, wherein the amount of the microstructure material filled in the intaglio is sequentially reduced. A method for manufacturing the microstructure according to any one of claims 1 to 5,
The step of applying the semi-solid fine structure material in the intaglio of the intaglio is characterized in that the semi-solid fine structure material is applied only to a part of the intaglio. Method.