JP2011003916A - Resin composition for nano-imprinting, and method of forming fine structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for nano-imprinting, softening at a low temperature and favorable in preservation stability.SOLUTION: The resin composition contains: a cationic polymerization compound which is crystalline and is solid at normal temperatures; and a photo cationic polymerization initiator.

Description

  The present invention relates to a photosensitive resin composition used for nanoimprinting and a method for producing a microstructure.

  In recent years, a technique called nanoimprint described in Non-Patent Document 1 has been proposed as a technique for manufacturing a fine structure such as a semiconductor element, a microreactor, a display element, a light emitting element, an ink jet recording head, and a microsensor with high accuracy. ing. This is a technique in which a master (generally called a mold) on which a predetermined fine concavo-convex pattern is formed is press-molded onto a resin or the like placed on a substrate, and the mold pattern is transferred to the resin.

  In general, the nanoimprint includes a thermal nanoimprint method and a UV nanoimprint method. Thermal nanoimprinting is a system in which a substrate on which a thermoplastic resin is placed is heated and softened, and then a mold is pressed to transfer a pattern onto the resin. On the other hand, the UV nanoimprint is a system in which a mold is pressed on a photosensitive resin on a substrate, irradiated with ultraviolet rays, the photosensitive resin is cured, the mold is removed, and a pattern is transferred to the resin.

  Also, thermal nanoimprinting and UV nanoimprinting, in which the photosensitive resin is softened with heat and then the mold is pressed and then irradiated with ultraviolet rays to cure the photosensitive resin, remove the mold, and transfer the pattern to the resin. A combination of these methods has also been proposed. This method can easily transfer a pattern in a low pressure and in a short time by softening by heating even a solid or high viscosity photosensitive resin at room temperature, which is difficult to transfer the mold pattern at room temperature. Can do. Therefore, there is an advantage that nanoimprint can be applied to various types of photosensitive resins.

  Patent Document 1 discloses a cationic polymerization type photosensitive resin composition suitable for UV nanoimprint, which includes an epoxy resin having a softening point at a low temperature.

Nanoimprint Application Cases (Information Organization Co., Ltd., September 18, 2007)

JP 2008-142940 A

  However, since the photosensitive resin composition described in Patent Document 1 has a softening point of the main component epoxy resin at a low temperature, the coated surface cannot be dried when applied to a substrate. There is a concern that kimono and the like are likely to occur. In addition, the adhering adhering matter is difficult to remove, which may affect the shape after pattern transfer.

  On the other hand, when patterning a solid monomer and / or prepolymer at room temperature by nanoimprinting, it is usually performed by heating the glass transition temperature or higher of the resin to soften the resin. However, in the case of monomers and / or prepolymers that are solid at room temperature, which are conventionally used in nanoimprinting, in order to achieve sufficient mold filling properties and thin residual film thickness, the heating temperature and applied pressure are increased. In some cases, it is necessary to take a measure such as extending the application time. However, an increase in heating temperature or applied pressure may cause damage or deterioration of the substrate, the mold, and the release agent formed on the mold surface. In addition, the extension of the heating and pressurizing time naturally has a problem that the time required for the entire process increases. Thus, when a solid monomer and / or prepolymer is used at room temperature having a relatively low glass transition temperature, the viscosity tends to be lowered by heating, so that the above-described mold filling property and remaining film thickness are improved. However, generally, as the glass transition temperature approaches normal temperature, the resin tends to cause blocking, resulting in poor storage stability in the solid state.

  The present invention has been made in view of the above, and an object of the present invention is to provide a photosensitive resin composition having excellent storage stability and capable of easily producing a pattern at a low pressure in a short time by a nanoimprint method. I will.

  An example of the present invention is a resin composition for nanoimprinting, which includes a cationically polymerizable compound that is crystalline at room temperature and is solid, and a cationic photopolymerization initiator.

  An example of the present invention includes a step of providing a resin composition containing a crystalline cationically polymerizable compound having a crystallinity at room temperature and a photocationic polymerization initiator on a substrate, and heating the resin composition. A step of melting the resin composition, a step of pressing the mold of the master having a mold against the molten resin composition, and irradiating the resin composition with light while the mold is pressed And a step of forming a microstructure by curing the resin composition.

  ADVANTAGE OF THE INVENTION According to this invention, the photosensitive resin composition which is excellent in storage stability and can produce a pattern easily by low pressure and a short time by the nanoimprint method can be provided.

The typical sectional view showing an example of the manufacturing method of the fine structure by the present invention. The typical sectional view showing an example of the manufacturing method of the fine structure by the present invention. 4A and 4B are diagrams for explaining a method of manufacturing a liquid discharge head according to the present invention.

  First, the resin composition for nanoimprints used in the present invention will be described.

  The resin composition for nanoimprinting used in the present invention contains a monomer and / or prepolymer that is a cationically polymerizable compound that is crystalline at room temperature and a photocationic polymerization initiator.

  Cationic polymerizable monomers and / or prepolymers having crystallinity show numerous crystal peaks by X-ray diffraction, the melting point is sharper than room temperature, and there is almost no intermolecular interaction at temperatures above the melting point. It has a low viscosity property. Examples of the cationic polymerizable monomer or prepolymer having crystallinity include, but are not limited to, a monomer or prepolymer having an epoxy group, a vinyl ether group, or an oxetane group.

  Preferred crystalline epoxy monomers or prepolymers include compounds represented by the following formula (1).

[However, G represents a glycidyl group, n represents a number of 0 or more, and X represents a group represented by any one of the following formula (A), the following formula (B), and the following formula (C). ]

(However, R < ₁ > -R < ₄ > shows a hydrogen atom, a halogen atom, or a C1-C6 alkyl group, respectively.)

(However, R < ₅ > -R < ₈ > shows a hydrogen atom, a halogen atom, or a C1-C6 alkyl group, respectively.)

(However, R < ₉ > -R < ₁₆ > shows a hydrogen atom, a halogen atom, or a C1-C6 alkyl group, respectively, Y is a group or single bond chosen from an oxygen atom, a sulfur atom, a methylene, and following formula (a) Indicate)

(However, R < ₁₇ > -R < ₂₀ > shows a hydrogen atom and a methyl group, respectively.)

  Examples of the compound represented by the formula (1) include, by name, diglycidyl ether of 4,4'-dihydroxybiphenyl and diglycidyl ether of 4,4'-dihydroxydiphenyl ether. Moreover, the diglycidyl ether of 3,3 ', 5,5'-tetramethyl-bisphenol F is also mentioned.

  In addition, diglycidyl ether of 4,4'-dihydroxydiphenyl sulfide, diglycidyl ether of 1,4-bis (3-methyl-4-hydroxycumyl) benzene, diglycidyl ether of hydroquinone, and the like can be given. Other examples include diglycidyl ester of terephthalic acid.

  Also, epoxy resins described in JP-A-8-092311, JP-A-2002-138130, JP-A-2002-338656, JP-A-2004-035762 and JP-A-2006-307011 can be used.

  Specifically, YDC-1312, YSLV-50TE, YSLV-80XY, YSLV-80DE, YSLV-90CR, YSLV-120TE, GK-8001, GK-4260 (trade name) manufactured by Tohto Kasei Co., Ltd. can be used. Examples also include Denacol EX-203, Denacol EX-711, Denacol EX-731 (trade name) manufactured by Nagase ChemteX Corporation, YX4000 series, YL6121 series, YL6640, YL6643, and YL6667 (trade name) manufactured by Japan Epoxy Resins. These monomers and prepolymers may be used alone or in combination of two or more.

  These crystalline monomers and prepolymers can be handled as solids at room temperature. The molecular weight is about 300 or more and 3000 or less.

  Furthermore, when forming a pattern by nanoimprinting, the viscosity becomes very low by heating above the melting point, so that the blocking resistance during storage and the pattern filling during nanoimprinting are improved and the remaining film thickness is reduced. Reduction can be made compatible. Furthermore, since it is a solid at room temperature, problems such as a reaction progressing during long-term storage and a decrease in reactivity during use are unlikely to occur, and the storage stability is high. The cationically polymerizable compound applicable to the present invention is not limited to the epoxy monomers and prepolymers exemplified above as long as it has crystallinity and can enjoy the above-described characteristics.

  The photocationic polymerization initiator is not particularly limited as long as it is a compound that generates cations by irradiation with active energy rays. Preferable examples include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, triazines and the like. Specific examples include BBI-103 and BBI-102 (trade name) manufactured by Midori Chemical.

  Moreover, you may add a sensitizer for the purpose of improving the reactivity as needed. Examples of the sensitizer include anthracene derivatives, anthraquinone derivatives, xanthone derivatives, thioxanthone derivatives, perylene derivatives, and benzophenone derivatives.

  Furthermore, additives such as an adhesion improver, an ion catcher, and an inorganic filler can be appropriately added as necessary without departing from the spirit of the present invention.

  In the case of a conventional photosensitive resin composition that is liquid at normal temperature, a uniform liquid cannot be obtained unless the compounds constituting the photosensitive resin composition are combined in consideration of the respective solubility, or deposited during long-term storage. Or separation may occur. On the other hand, it is not necessary to consider these problems in the photosensitive resin composition used in the present invention, and it is also possible to use a compound having low solubility in a solvent that has been difficult to use in the past.

  It is desirable that all of the compounds constituting these photosensitive resin compositions have a melting point of 50 ° C. or higher and 170 ° C. or lower. If it is higher than this, a considerably high temperature is required for processing by nanoimprint, and the load on the nanoimprint apparatus, mold, release agent and the like is large.

  Then, the manufacturing method of the microstructure using the said resin composition for nanoimprint in this invention is demonstrated using figures.

  (1) Provide and install the photosensitive resin composition 101 on the substrate 102 (FIG. 1-a).

  The photosensitive resin composition 101 may be in a powder form or may be formed in a pellet form. In the case of powder, the amount and position of the pattern placed on the substrate 102 can be freely controlled according to the density and depth of the pattern of the mold to be transferred. is there. On the other hand, the pellet form is easy to handle, and when the amount used is always constant, it is not necessary to measure and control the amount installed on the substrate every time.

  In addition, since the powder and the substrate are naturally dried in this state, the adsorbing of foreign matters is more than when a photosensitive resin composition that is liquid at room temperature or a photosensitive resin composition having a low softening point is applied to the substrate. Is reduced.

  (2) Next, the photosensitive resin composition 101 is melted by heating (FIG. 1-b).

  Since the photosensitive resin composition 101 is crystalline, when heated to a temperature higher than the temperature at which the photosensitive resin composition 101 melts, it rapidly becomes a liquid having a low viscosity and spreads on the substrate. Further, since it does not contain a volatile compound such as a solvent or a reactive diluent, it is easy to handle and the usage load is reduced.

  (3) Next, the mold part of the mold 103, which is a master plate that transmits the active energy rays formed with a convex shape of the target structure, is pressed against the photosensitive resin composition 101 (FIG. 1-c). The width of the convex shape is about 1 to 20 μm at a fine part and about 50 to 200 μm at a wide part. Of course, it is not limited to this.

  In the process of pressing the surface of the mold 103 on which the convex shape is formed, the resin composition 101 is spread over the entire pattern and filled between the convex portions of the mold. Between the convex parts, if the convex tip or middle is taken as a reference, it becomes a concave part. Moreover, the pressure at the time of pressing the mold 103 can take a suitable value according to the physical properties of the resin composition 101. For example, it is 0.1-10 MPa. Furthermore, these nanoimprint processes may be performed in a vacuum or in a reduced pressure so that bubbles or the like do not remain between the resin composition 101 and the mold 103.

  As the mold 103 that transmits the active energy ray, any part of the active energy ray necessary for the resin composition 101 to cure may be transmitted, and examples thereof include glass, quartz, and resin. In view of the durability of the mold and the like, a replica transferred from the mold may be used as the mold 103.

  It is also possible to simplify the steps (2) and (3) by pressing a mold that has been heated sufficiently and in advance against the photosensitive resin composition 101 and performing pressing while melting the photosensitive resin composition 101. is there.

  (4) Next, the photosensitive resin composition 101 is irradiated with an active energy ray 104 to be cured to obtain a cured product (FIG. 1-d).

  The active energy ray 104 is not particularly limited as long as the resin composition 101 is cured. For example, ultraviolet rays, visible rays, infrared rays, X-rays, γ rays and the like can be mentioned. Among these, ultraviolet rays are preferably used. Moreover, since the resin composition 101 is heated, the curing reaction is accelerated as compared to exposure at normal temperature. Further, for the purpose of accelerating the curing reaction, the heated state may be maintained for a while after irradiation with the active energy ray.

  (5) The mold 103 is removed from the photosensitive resin composition 101 (FIG. 1-e).

  As a method for removing the mold 103, peeling, melting, melting, and the like can be given. In order to prevent a part of the resin composition 101 from adhering to the mold 103 during peeling, a mold release treatment such as applying a mold release agent to the mold 103 may be performed. Examples of mold release agents include 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane, 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane, and 1H, 1H, 2H, 2H-perfluorododecyltrichlorosilane. Can be mentioned. Further, 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane, 1H, 1H, 2H, 2H-perfluorododecyltrimethoxysilane can be mentioned. Further, 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorododecyltriethoxysilane and the like can be mentioned. . Other examples include OPTOOL series (trade name) manufactured by Daikin Industries, Novec EGC-1720 (trade name) manufactured by Sumitomo 3M, NANOS series (trade name) manufactured by T & K, diamond-like carbon (DLC), etc. Can do. The mold release treatment can be performed by a suitable method depending on the mold release agent used, such as dipping, spin coating, slit coating, spray coating, and vapor deposition.

  Thereby, a fine structure can be obtained. The method for manufacturing a microstructure of the present invention is a method suitable for manufacturing a semiconductor element, a microfluidic chip, a display element, an ink jet recording head, a microsensor, and the like.

  Moreover, it is also possible to use the master itself on which the epoxy film is formed as a component in the above field without removing the mold as the master.

Example 1
The solid of each compound shown in Table 1 was pulverized in an agate mortar, and the mixed powder was used as a photosensitive resin composition.

  Next, the following was performed as a mold release treatment. A quartz mold NIM-PH3000 (trade name) for nanoimprinting manufactured by NTT-AT Nanofabrication Co., Ltd. was dipped on a release agent Durasurf HD-1101TH (trade name) manufactured by Harves. And after standing still at room temperature for 24 hours, it rinsed with Sumitomo 3M Novec HFE-7100 (brand name), and the excess mold release agent was removed.

Next, 20 mg of the resin composition powder was placed on a 4-inch silicon substrate. And the silicon substrate was heated at 130 degreeC with the nanoimprint apparatus LTNIP-2000 (brand name) by a Risotech Japan company, and the said resin composition was fuse | melted. Next, the resin composition was pressed at a pressure of 3.5 MPa using the quartz mold. After being held for 15 seconds in the pressed state, the resin composition was irradiated with ultraviolet rays at an exposure amount of 1000 mJ / cm ² . Next, the quartz mold was released, and the substrate was cooled to room temperature to obtain a fine structure pattern.

  The appearance and cross section of the produced pattern were observed with a scanning electron microscope, and the shape of the pattern and the remaining film thickness were examined. As a result, no depressions or the like were found in the pattern, and the remaining film thickness was 17 nm on average.

  Further, when the powder of the photosensitive resin composition was stored at room temperature for 1 month and observed visually, no change was observed in the appearance of the powder.

(Comparative Example 1)
Nanoimprinting was performed in the same manner as in Example 1 except that the solid of each compound shown in Table 2 was pulverized in an agate mortar and the mixed powder was prepared as a photosensitive resin composition.

  The appearance and cross section of the produced pattern were observed with a scanning electron microscope, and the pattern shape and the remaining film thickness were examined. As a result, no depression was observed in the pattern, and the remaining film thickness was 233 nm on average.

  Moreover, when the powder of the said photosensitive resin composition was stored visually at normal temperature for one month, when it observed visually, blocking occurred and the powder was adhering.

(Example 2)
Fabrication of Thermal Inkjet Recording Head First, a quartz mold 203 was prepared in which an ink ejection port for ejecting ink droplets and an ink flow path pattern for supplying ink to the ink ejection port were formed (see FIG. 2-a). As a mold release treatment, the quartz mold 203 was dipped in a release agent Durasurf HD-1101TH (trade name) manufactured by Harves. And after leaving still at room temperature for 24 hours, it rinsed with the Sumitomo 3M company make Novec HFE-7100 (brand name), and the excess mold release agent was removed. The mold 203 is three-dimensionally formed according to the shape of the head as shown in the perspective view of FIG.

Next, 25 mg of powder 201 obtained by pulverizing and mixing each compound shown in Table 1 was placed on a 4-inch silicon substrate 202 (FIG. 2B). Next, the silicon substrate 202 was heated to 130 ° C. with a nanoimprint apparatus LTNIP-2000 (trade name) manufactured by RISOTEC JAPAN, and the photosensitive resin composition 201 was melted (FIG. 2C). Next, the resin composition 201 was pressed with a pressure of 3.5 MPa using a quartz mold 203 (FIG. 2D). After holding for 15 seconds in the pressed state, the resin composition 201 was irradiated with ultraviolet rays at an exposure amount of 1000 mJ / cm ² (FIG. 2E). Next, the quartz mold 203 was released, and the substrate was cooled to room temperature to obtain a resin composition 201 in which ink discharge ports and ink flow paths were formed (FIG. 2-f).

  Next, the residual film was removed by etching the resin composition 201 with oxygen by reactive ion etching (RIE). Furthermore, the resin composition 201 was bonded to a silicon substrate 205 on which an electrothermal conversion element 206 and an ink supply port (not shown) for supplying ink were formed as energy generating elements for generating ink discharge energy. (FIG. 2-g).

  Next, the silicon substrate 205 supporting the resin composition 201 was removed, and a thermal ink jet recording head was completed (FIG. 2-h). As shown in FIG. 3B, the mold part becomes the flow path 208 and the discharge port 207, and the flow path forming member 209 is formed. The discharge ports 207 are arranged in a predetermined direction, and energy generation elements 206 corresponding to the discharge ports are provided.

101 201 Photosensitive resin composition 102 202 Substrate 103 203 Mold

Claims (9)

  A resin composition for nanoimprinting, which comprises a cationically polymerizable compound that is crystalline at normal temperature and a photocationic polymerization initiator.   The sensitizer of the said photocationic polymerization initiator is included, The resin composition for nanoimprints of Claim 1 characterized by the above-mentioned.   The resin composition for nanoimprint according to claim 2, wherein melting points of the cationically polymerizable compound, the photocationic polymerization initiator, and the sensitizer are 50 ° C or higher and 170 ° C or lower, respectively. object. 4. The nanoimprint resin composition according to claim 1, wherein the cationically polymerizable compound is represented by Formula (1). 5.

[However, G represents a glycidyl group, n represents a number of 0 or more, and X represents a group represented by any one of the following formula (A), the following formula (B), and the following formula (C). ]

(However, R < ₁ > -R < ₄ > shows a hydrogen atom, a halogen atom, or a C1-C6 alkyl group, respectively.)

(However, R < ₅ > -R < ₈ > shows a hydrogen atom, a halogen atom, or a C1-C6 alkyl group, respectively.)
(However, R < ₉ > -R < ₁₆ > shows a hydrogen atom, a halogen atom, or a C1-C6 alkyl group, respectively, Y is a group or single bond chosen from an oxygen atom, a sulfur atom, a methylene, and following formula (a) Is shown.)

(However, R < ₁₇ > -R < ₂₀ > shows a hydrogen atom and a methyl group, respectively.)   The nanoimprint resin composition according to any one of claims 1 to 4, wherein the nanoimprint resin composition is in a powder form.   6. The resin composition according to claim 1, wherein the molecular weight of the cationically polymerizable compound is 300 or more and 3000 or less. Providing the resin composition according to any one of claims 1 to 6 on a substrate;
Melting the resin composition by heating the resin composition;
Pressing the mold of the master with the mold against the molten resin composition;
Irradiating the resin composition with light in a state where the mold is pressed to cure the resin composition, thereby forming a fine structure;
A method for forming a microstructure characterized by comprising: Providing the resin composition according to any one of claims 1 to 6 on a substrate;
A step of melting the resin composition by pressing the mold of a master having a mold heated to a temperature at which the resin composition is melted or higher, against the resin composition;
Irradiating the resin composition with light in a state where the mold is pressed to cure the resin composition, thereby forming a fine structure;
A method for forming a microstructure characterized by comprising:   The method for forming a microstructure according to claim 7 or 8, further comprising a step of removing the master from the cured product after curing the resin composition to obtain a cured product.