JP2009208239A - Pattern forming method - Google Patents

Abstract

There is provided a pattern forming method capable of forming a pattern having both fine pattern formability and film hardness by an optical nanoimprint method.
An application step of applying a photocurable composition onto a substrate, a pressure-bonding step of pressing a mold onto the photocurable composition applied onto the substrate, and the photocurable composition A photocuring step of photocuring to form a reversal pattern 2 of the mold, wherein the photocurable composition has a content of a component having a molecular weight of 1000 or more with respect to all components excluding the solvent of 30% by mass or less. And the temperature (X) of the said photocurable composition in the said crimping | compression-bonding process is 30 degreeC or more, The pattern formation method characterized by the above-mentioned.
[Selection] Figure 1

Description

  The present invention relates to a pattern forming method using nanoimprint lithography. More specifically, semiconductor integrated circuits, flat screens, micro electromechanical systems (MEMS), sensor elements, optical recording media such as high density memory disks, optical components such as diffraction grating relief holograms, nano devices, optical devices, Optical films and polarizing elements for manufacturing flat panel displays, thin film transistors for liquid crystal displays, organic transistors, color filters, overcoat layers, pillar materials, rib materials for liquid crystal alignment, microlens arrays, immunoassay chips, DNA separation chips The present invention relates to a method for forming a fine pattern by an optical nanoimprint method used for manufacturing a microreactor, a nanobio device, an optical waveguide, an optical filter, a photonic liquid crystal, and the like.

  The nanoimprint method has been developed by developing an embossing technique that is well-known in optical disc production, and mechanically pressing a mold master (generally called a mold, stamper, or template) with a concavo-convex pattern onto a resist. This is a technology that precisely deforms and transfers fine patterns. Once the mold is made, it is economical because nanostructures and other microstructures can be easily and repeatedly molded, and it is economical, and since it is a nano-processing technology with less harmful waste and emissions, it has recently been applied to various fields. Is expected.

In such a nanoimprint method, the following applied technologies have been proposed.
The first technique is a case where a molded shape (pattern) itself has a function and can be applied as various nanotechnology element parts or structural members. Examples include various micro / nano optical elements, high-density recording media, optical films, and structural members in flat panel displays. The second technology is to build a laminated structure by simultaneous integral molding of microstructure and nanostructure and simple interlayer alignment, and apply this to the production of μ-TAS (Micro-Total Analysis System) and biochips. It is what. The third technique is used for processing a substrate by a method such as etching using the formed pattern as a mask. In this technology, high-precision alignment and high integration enable high-density semiconductor integrated circuit fabrication, liquid crystal display transistor fabrication, and magnetic media for next-generation hard disks called patterned media instead of conventional lithography technology. It can be applied to processing. In recent years, efforts have been made to put the nanoimprint method relating to these applications into practical use.

  As an application example of the nanoimprint method, first, an application example for manufacturing a high-density semiconductor integrated circuit will be described. 2. Description of the Related Art In recent years, semiconductor integrated circuits have been miniaturized and integrated, and photolithography apparatuses have been improved in accuracy as a pattern transfer technique for realizing the fine processing. However, it has become difficult to satisfy three requirements of fine pattern resolution, apparatus cost, and throughput for further miniaturization requirements. On the other hand, nanoimprint lithography (optical nanoimprint method) has been proposed as a technique for performing fine pattern formation at low cost. For example, Patent Documents 1 and 3 below disclose a nanoimprint technique in which a silicon wafer is used as a stamper and a fine structure of 25 nm or less is formed by transfer. In this application, a pattern forming property of a level of several tens of nanometers and a high etching resistance for functioning as a mask during substrate processing are required.

  An application example of the nanoimprint method to the production of the next generation hard disk drive (HDD) will be described. HDDs have a history of both high-capacity and miniaturization, with both high-performance heads and high-performance media. From the viewpoint of improving the performance of media, HDDs have increased in capacity by increasing the surface recording density. However, when the recording density is increased, so-called magnetic field spreading from the side surface of the magnetic head becomes a problem. Since the magnetic field spread does not become smaller than a certain value even if the head is made smaller, a phenomenon called sidelight occurs as a result. When side writing occurs, writing to an adjacent track occurs during recording, and already recorded data is erased. Further, due to the magnetic field spread, a phenomenon such as reading an excessive signal from an adjacent track occurs during reproduction. In order to solve such a problem, technologies such as discrete track media and bit patterned media have been proposed which are solved by filling the spaces between tracks with a nonmagnetic material and physically and magnetically separating the tracks. The application of nanoimprinting has been proposed as a method for forming a magnetic or nonmagnetic pattern in the production of these media. Also in this application, a pattern forming property of several tens of nm level and high etching resistance for functioning as a mask during substrate processing are required.

Next, an application example of the nanoimprint method to a flat display such as a liquid crystal display (LCD) or a plasma display (PDP) will be described.
With the trend toward larger and higher definition LCD substrates and PDP substrates, the optical nanoimprint method has recently attracted attention as an inexpensive lithography that replaces the conventional photolithography method used in the manufacture of thin film transistors (TFTs) and electrode plates. Yes. Therefore, it has become necessary to develop a photo-curable resist that replaces the etching photoresist used in the conventional photolithography method.
Further, as a structural member such as an LCD, application of the optical nanoimprint method to a transparent protective film material described in the following Patent Documents 4 and 5 or a spacer described in the following Patent Document 5 has begun to be studied. Unlike the etching resist, such a resist for a structural member is finally left in the display, and is sometimes referred to as “permanent resist” or “permanent film”.
In addition, a spacer that defines a cell gap in a liquid crystal display is also a kind of permanent film. In conventional photolithography, a photocurable composition comprising a resin, a photopolymerizable monomer, and an initiator has been widely used. (For example, see Patent Document 6). The spacer is generally a pattern having a size of about 10 μm to 20 μm by photolithography after applying the photocurable composition after forming the color filter on the color filter substrate or after forming the protective film for the color filter. Is formed by further heat-curing by post-baking.

In addition, microelectromechanical systems (MEMS), sensor elements, optical components such as diffraction gratings and relief holograms, nanodevices, optical devices, optical films and polarizing elements for the production of flat panel displays, thin film transistors for liquid crystal displays, organic transistors , Color filter, overcoat layer, pillar material, rib material for liquid crystal alignment, microlens array, immunoassay chip, DNA separation chip, microreactor, nanobiodevice, optical waveguide, optical filter, photonic liquid crystal, etc. The nanoimprint method is also useful for applications.
In these permanent film applications, the formed pattern will eventually remain in the product, so the durability of the film, mainly heat resistance, light resistance, solvent resistance, scratch resistance, high mechanical properties against external pressure, hardness, etc. And strength-related performance is required.
As described above, most of the patterns conventionally formed by the photolithography method can be formed by nanoimprinting, and attention has been paid as a technique capable of forming a fine pattern at low cost.

  Two types of nanoimprint methods have been proposed: a thermal imprint method using a thermoplastic resin as a material to be processed (Non-Patent Document 1) and a photoimprint method using a photocurable composition (Non-Patent Document 2). Yes. In the case of thermal nanoimprinting, the mold is pressed onto a polymer resin heated to a temperature higher than the glass transition temperature, and the mold is released after cooling to transfer the microstructure to the resin on the substrate. Since it can be applied to various resin materials and glass materials, it is expected to be applied in various fields. For example, Patent Document 1 and Patent Document 2 disclose a nanoimprint method for forming a nanopattern at low cost using a thermoplastic resin.

US Pat. No. 5,772,905 US Pat. No. 5,956,216 US Pat. No. 5,259,926 JP 2005-197699 A Japanese Patent Laying-Open No. 2005-301289 Japanese Patent Laid-Open No. 2004-240241

S. Chou et al .: Appl. Phys. Lett. Vol. 67, 3114 (1995) M. Colbun et al,: Proc.SPIE, Vol. 3676,379 (1999)

  However, in the case of the above-mentioned thermal nanoimprint method, high temperature and high pressure conditions are required when the mold is pressed. For this reason, heating at the time of pressing the mold generally requires heating at 100 ° C. or higher, and pattern accuracy deteriorates due to thermal expansion, and there is a problem of reduced throughput due to temperature rising, holding and cooling processes, and high pressure conditions. Therefore, there is a problem that application to a large area substrate is difficult.

On the other hand, in the photo nanoimprint method, light is irradiated through a transparent mold, and the curable composition for photo nanoimprint lithography is photocured to form a pattern. For this reason, in the optical nanoimprint method, it is not necessary to press the mold under normal high temperature and high pressure conditions, and imprinting at room temperature and low pressure is possible. However, the curable composition used in the optical nanoimprint method is required to have a very low viscosity in order to ensure pattern formability, particularly mold filling property, and to reduce the remaining film of the formed pattern. Therefore, the choice of materials is limited, and as a result, it is difficult to improve the characteristics of the pattern to be formed.
In order to use the nanoimprint method industrially, it is premised that a good pattern is formed, but at the same time, as described above, etching resistance, heat resistance, light resistance, solvent resistance, scratch resistance, pattern durability, etc. Film characteristics according to the application are required. Conventionally, it has been difficult to simultaneously achieve pattern forming properties and film properties.

  In order to solve the above problems, an object of the present invention is to form a pattern by photocuring a curable composition to form a pattern, which has excellent fine pattern formability corresponding to a nanometer pattern and high film hardness. It is an object of the present invention to provide a pattern forming method capable of forming a pattern having the following.

[1] An application step of applying a photocurable composition onto a substrate;
A pressure-bonding step in which a mold is pressure-bonded to the photocurable composition applied on the substrate;
A photocuring step of photocuring the photocurable composition to form a reversal pattern of the mold;
The photocurable composition contains a resin component having a weight average molecular weight of 2000 or more with respect to all components excluding the solvent of 30% by mass or less, and the temperature of the photocurable composition in the press-bonding step. (X) is 30 degreeC or more, The pattern formation method characterized by the above-mentioned.

[2] The pattern forming method according to [1], wherein the applying step includes a step of heating the photocurable composition to remove the solvent.

[3] The pattern forming method according to [1] or [2], wherein the press-bonding step includes a step of heating the photocurable composition applied on the substrate.

[4] The pattern forming method as described in any one of [1] to [3], wherein the viscosity of the component excluding the solvent of the photocurable composition is 5 to 2000 mPa · s at 25 ° C. .

[5] The temperature (X) of the photocurable composition is such that the viscosity of the photocurable composition applied on the substrate is 1 to 100 mPa.s. The pattern forming method according to any one of [1] to [4], wherein the temperature is s.

[6] The pattern forming method as described in any one of [1] to [5], wherein the pattern formed in the photocuring step contains a pattern having a minimum dimension of 1 nm to 50 μm.

[7] In the temperature (X) of the photocurable composition, the viscosity of the photocurable composition applied on the substrate is 1 to 100 mPa · s. 6]. The pattern forming method according to any one of [6].

[8] The pattern formation according to any one of [1] to [7], wherein the pressure-bonding step pressure-bonds the mold to the photocurable composition at a pressure of 0.1 MPa to 1 MPa. Method.

[9] The pattern forming method as described in any one of [1] to [8], wherein the temperature (X) of the photocurable composition is 30 ° C to 150 ° C.

[10] The pattern forming method as described in any one of [1] to [9], wherein the photocurable composition contains a polymerizable monomer and a photopolymerization initiator.

  According to the pattern forming method of the present invention, a pattern having both fine pattern formability and film hardness can be formed by an optical nanoimprint method.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

In the present specification, “(meth) acrylate” represents acrylate and methacrylate, “(meth) acryl” represents acryl and methacryl, and “(meth) acryloyl” represents acryloyl and methacryloyl. In the present specification, “monomer” and “monomer” are synonymous. The monomer in the present invention is distinguished from an oligomer and a polymer, and refers to a compound having a weight average molecular weight of 1,000 or less. In the present specification, “functional group” refers to a group involved in a polymerization reaction.
The “nanoimprint” in the present invention refers to pattern transfer having a size of about several nm to several μm.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what has a substituent with what does not have a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

<Pattern formation method>
The pattern forming method of the present invention includes an application step (step 1) of applying a photocurable composition onto a substrate, and a pressure-bonding step of pressing a mold onto the photocurable composition applied onto the substrate (step 1). Step 2) and a photocuring step (Step 3) for photocuring the photocurable composition to form a reversal pattern of the mold, wherein the photocurable composition is based on all components except the solvent. The content of the resin component having a weight average molecular weight of 2000 or more is 30% by mass or less, and the temperature (X) of the photocurable composition in the press bonding step is 30 ° C. or more. The pattern formation method of this invention may include the process of heating the said photocurable composition provided on the said base material in the said provision process. Furthermore, the pattern formation method of this invention may include the process of heating the said photocurable composition provided on the said base material in the said crimping | compression-bonding process.

In the pattern forming method of the present invention, since the mold is pressure-bonded to the curable composition in a heated state, the viscosity of the photocurable composition on the substrate is lowered during the pressure bonding of the mold. Thereby, the mold filling property of the photocurable composition on the base material is improved, and a rectangular pattern (fine pattern) can be obtained even when the pressure at the time of mold pressing is low.
Further, in the thermal imprint method, if the mold is cooled after the pattern is transferred and then the mold is not peeled off from the pattern, the formed pattern is destroyed. For this reason, it is difficult to improve the throughput in the thermal imprint method. On the other hand, in the pattern formation method of the present invention, since the pattern is formed by the photoimprint method, the pattern is not destroyed even if it is peeled off from the cured composition (pattern) without cooling the mold after light irradiation. Therefore, the throughput can be easily improved.
Furthermore, in the conventional photoimprint method, when a high-viscosity photocurable composition is used so that the cured film characteristics are good, it is necessary to pressure-bond the mold at a high pressure, resulting in mold durability and pattern formability. There's a problem. On the other hand, in the pattern forming method of the present invention, a composition having a high viscosity at room temperature can be obtained by pressure-bonding the mold to the photocurable composition while heating (with the temperature of the composition being 30 ° C. or higher). The mold is smoothly filled, and the pattern formability is improved.

[Granting process: Process 1]
The application | coating process in this invention is a process of providing a photocurable composition on a base material. In the present invention, the “base material” includes a substrate or a support. Examples of the substrate (substrate or support) to which the photocurable composition is applied include quartz, glass, optical film, ceramic material, vapor deposition film, magnetic film, reflection film, Ni, Cu, Cr, Fe, and the like. Metal substrate, paper, SOG (spin on glass), polyester film, polycarbonate film, polymer film such as polyimide film, TFT array substrate, PDP electrode plate, glass or transparent plastic substrate, conductive substrate such as ITO or metal, There are no particular restrictions on insulating substrates, semiconductor fabrication substrates such as silicone, silicone nitride, polysilicon, silicone oxide, and amorphous silicone. Further, the shape of the substrate is not particularly limited, and may be a plate shape or a roll shape. Furthermore, as described later, as the substrate, a light transmissive or non-light transmissive material can be selected according to the combination with the mold or the like.

The method for applying the photocurable composition on the substrate is not particularly limited, and a known coating method or the like can be appropriately used. Examples of known coating methods include dip coating, air knife coating, curtain coating, wire bar coating, gravure coating, extrusion coating, spin coating, slit scanning, and ink jet. .
In the application | coating process in this invention, a photocurable composition is provided on a base material, It is made to dry as needed, and a pattern receptor is produced.

(Photocurable composition)
In the pattern forming method of the present invention, a photocurable composition is used. In the photocurable composition of the present invention, the content of components having a molecular weight of 1000 or more with respect to all components excluding the solvent is 30% by mass or less. In the photocurable composition of the present invention, when the content of components having a molecular weight of 1000 or more with respect to all components excluding the solvent exceeds 30% by mass, the composition viscosity becomes too high, and the method of the present invention. Even if is used, the pattern formability deteriorates. The content of the component having a molecular weight of 1000 or more with respect to all components excluding the solvent is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, and most preferably 0 to 2% by mass or less. From the viewpoint of pattern formation, it is preferable that the number of components having a molecular weight of 1000 or more is as small as possible, and it is preferable that substantially no components having a molecular weight of 1000 or more are included except for surfactants and trace amounts of additives. When the component having a molecular weight of 1000 or more is a resin or oligomer mixture, the molecular weight is based on the weight average molecular weight.

  As a photocurable composition used for this invention, a photocationic curable composition and a photoradical curable composition are mentioned, A photoradical curable composition is preferable. The photocurable composition in the present invention is preferably a composition containing a polymerizable monomer having a polymerizable functional group and a photopolymerization initiator.

-Polymerizable monomer-
Examples of the polymerizable monomer include a polymerizable unsaturated monomer having 1 to 6 ethylenically unsaturated bond-containing groups; a compound having an oxirane ring (epoxy compound); a vinyl ether compound; a styrene derivative; and a fluorine atom. Examples thereof include propenyl ether and butenyl ether, and a polymerizable unsaturated monomer having 1 to 6 ethylenically unsaturated bond-containing groups is preferred from the viewpoints of curability and composition viscosity.

The polymerizable unsaturated monomer having 1 to 6 ethylenically unsaturated bond-containing groups (1 to 6 functional polymerizable unsaturated monomer) will be described.
First, specific examples of the polymerizable unsaturated monomer having one ethylenically unsaturated bond-containing group (monofunctional polymerizable unsaturated monomer) include 2-acryloyloxyethyl phthalate, 2-acryloyloxy 2 -Hydroxyethyl phthalate, 2-acryloyloxyethyl hexahydrophthalate, 2-acryloyloxypropyl phthalate, 2-ethyl-2-butylpropanediol acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylhexyl carbitol (meth) Acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 4-hydroxy Butyl (medium ) Acrylate, acrylic acid dimer, benzyl (meth) acrylate, butanediol mono (meth) acrylate, butoxyethyl (meth) acrylate, butyl (meth) acrylate, cetyl (meth) acrylate, ethylene oxide modified (hereinafter referred to as “EO”) Cresol (meth) acrylate, dipropylene glycol (meth) acrylate, ethoxylated phenyl (meth) acrylate, ethyl (meth) acrylate, isoamyl (meth) acrylate, isobutyl (meth) acrylate, isooctyl (meth) acrylate, cyclohexyl (meth) Acrylate, isobornyl (meth) acrylate, dicyclohentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, isomyristyl (meth) ) Acrylate, lauryl (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxytripropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methyl (meth) acrylate, Neopentyl glycol benzoate (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolypropylene glycol (meth) acrylate, octyl (meth) acrylate, paracumylphenoxyethylene glycol (meth) acrylate, epichlorohydrin (hereinafter “ ECH)) Modified phenoxy acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (Meth) acrylate, phenoxyhexaethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, stearyl (meta ) Acrylate, EO-modified succinic acid (meth) acrylate, tert-butyl (meth) acrylate, tribromophenyl (meth) acrylate, EO-modified tribromophenyl (meth) acrylate, tridodecyl (meth) acrylate, p-isopropenylphenol, Styrene, α-methylstyrene, acrylonitrile, diethylene glycol monoethyl ether (meth) acrylate, N-vinyl pyrrolidone, N-vinyl cap Lactams, 1- or 2-naphthyl (meth) acrylate, 1- or 2-naphthylmethyl (meth) acrylate.
Among these, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclohentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, N-vinylpyrrolidone, 1- or 2-naphthyl ( Meth) acrylate, 1- or 2-naphthylmethyl (meth) acrylate is preferably used in the present invention.

  Examples of the bifunctional polymerizable unsaturated monomer having two ethylenically unsaturated bond-containing groups that can be preferably used in the present invention include dimethylol dicyclopentane di (meth) acrylate and di (meth) acrylic. Isocyanurate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, EO-modified 1,6-hexanediol di (meth) acrylate, ECH-modified 1,6-hexanediol Di (meth) acrylate, allyloxypolyethylene glycol acrylate, 1,9-nonanediol di (meth) acrylate, EO modified bisphenol A di (meth) acrylate, PO modified bisphenol A di (meth) acrylate, modified bisphenol A di (meta) ) Acrylate, EO-modified bisphenol Di (meth) acrylate, ECH-modified hexahydrophthalic acid diacrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, EO-modified neopentyl glycol diacrylate, propylene oxide (hereinafter “PO”) ) Modified neopentyl glycol diacrylate, caprolactone modified hydroxypivalate ester neopentyl glycol, stearic acid modified pentaerythritol di (meth) acrylate, ECH modified phthalic acid di (meth) acrylate, poly (ethylene glycol-tetramethylene glycol) ) Di (meth) acrylate, poly (propylene glycol-tetramethylene glycol) di (meth) acrylate, polyester (di) acrylate Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ECH-modified propylene glycol di (meth) acrylate, silicone di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) ) Acrylate, dimethylol tricyclodecane di (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate, tripropylene glycol di (meth) acrylate, EO modified tripropylene glycol di (meth) acrylate, triglycerol di (Meth) acrylate, dipropylene glycol di (meth) acrylate, divinylethyleneurea, divinylpropyleneurea are exemplified.

  Among these, neopentyl glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl hydroxypivalate Glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and the like are preferably used in the present invention.

  Examples of the polyfunctional polymerizable unsaturated monomer having 3 or more ethylenically unsaturated bond-containing groups include ECH-modified glycerol tri (meth) acrylate, EO-modified glycerol tri (meth) acrylate, PO-modified glycerol tri (meta) ) Acrylate, pentaerythritol triacrylate, EO modified phosphoric acid triacrylate, trimethylolpropane tri (meth) acrylate, caprolactone modified trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylol Propane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) Acrylate, dipentaerythritol hydroxypenta (meth) acrylate, alkyl-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol poly (meth) acrylate, alkyl-modified dipentaerythritol tri (meth) acrylate, ditrimethylolpropane tetra (meth) Examples include acrylate, pentaerythritol ethoxytetra (meth) acrylate, and pentaerythritol tetra (meth) acrylate.

  Among these, EO-modified glycerol tri (meth) acrylate, PO-modified glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, pentaerythritol tetra (meth) acrylate and the like are preferably used in the present invention.

  For the purpose of further increasing the crosslinking density, the photocurable composition in the present invention may be blended with a polyfunctional oligomer having a molecular weight larger than that of the polyfunctional polymerizable monomer within the range of achieving the object of the present invention. it can. Examples of the polyfunctional oligomer having photoradical polymerizability include various (meth) acrylate oligomers such as ester (meth) acrylate, urethane (meth) acrylate, ether (meth) acrylate, and epoxy (meth) acrylate.

  As the polymerizable monomer used in the present invention, a compound having an oxirane ring (epoxy compound) can also be employed. Examples of the compound having an oxirane ring include polyglycidyl esters of polybasic acids, polyglycidyl ethers of polyhydric alcohols, polyglycidyl ethers of polyoxyalkylene glycols, polyglycidyl ethers of aromatic polyols, and aromatics. Mention may be made, for example, of hydrogenated compounds of polyglycidyl ethers of polyols, urethane polyepoxy compounds and epoxidized polybutadienes. These compounds can be used alone or in combination of two or more thereof.

  Examples of the compound having an oxirane ring (epoxy compound) that can be preferably used in the present invention include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, Brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol di Polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin. Diglycidyl esters of aliphatic long-chain dibasic acids; monoglycidyl ethers of higher aliphatic alcohols; monoglycidyl ethers of polyether alcohols obtained by adding phenol, cresol, butylphenol or alkylene oxide to these; higher fatty acids The glycidyl esters of

  Among these, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol Diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether are preferred.

  Commercially available products that can be suitably used as the glycidyl group-containing compound include UVR-6216 (manufactured by Union Carbide), glycidol, AOEX24, cyclomer A200, (manufactured by Daicel Chemical Industries, Ltd.), Epicoat 828, Epicoat 812, Epicoat 1031, Epicoat 872, Epicoat CT508 (above, manufactured by Yuka Shell Co., Ltd.), KRM-2400, KRM-2410, KRM-2408, KRM-2490, KRM-2720, KRM-2750 (above, Asahi Denka Kogyo ( Product)). These can be used alone or in combination of two or more.

  The production method of these compounds having an oxirane ring is not limited. For example, Maruzen KK Publishing, 4th edition Experimental Chemistry Course 20 Organic Synthesis II, 213, 1992, Ed. By Alfred Hasfner, The chemistry of cyclic compounds-Small Ring Heterocycles part3 Oxiranes, John & Wiley and Sons, An Interscience Publication, New York, 1985, Yoshimura, Adhesion, Vol. 29, No. 12, 32, 1985, Yoshimura, Adhesion, Vol. 30, No. 5, 42, 1986, Yoshimura, Adhesion, Vol. 30, No. 7, 42, 1986, Japanese Patent Application Laid-Open No. 11-1000037, Japanese Patent No. 2906245, Japanese Patent No. 2926262 and the like can be synthesized.

As the polymerizable monomer used in the present invention, a vinyl ether compound may be used.
The vinyl ether compound can be appropriately selected from known ones, such as 2-ethylhexyl vinyl ether, butanediol-1,4-divinyl ether, diethylene glycol monovinyl ether, diethylene glycol monovinyl ether, ethylene glycol divinyl ether, triethylene glycol divinyl ether. 1,2-propanediol divinyl ether, 1,3-propanediol divinyl ether, 1,3-butanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, tri Methylolpropane trivinyl ether, trimethylolethane trivinyl ether, hexanediol divinyl ether, Raethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, ethylene glycol diethylene vinyl ether, triethylene glycol diethylene vinyl ether, ethylene glycol dipropylene vinyl ether, triethylene glycol diethylene Vinyl ether, trimethylolpropane triethylene vinyl ether, trimethylolpropane diethylene vinyl ether, pentaerythritol diethylene vinyl ether, pentaerythritol triethylene vinyl ether, pentaerythritol tetraethylene vinyl ether, 1,1,1 Tris [4- (2-vinyloxy ethoxy) phenyl] ethane, bisphenol A divinyloxyethyl carboxyethyl ether.

  These vinyl ether compounds can be obtained, for example, by the method described in Stephen C. Lapin, Polymers Paint Color Journal. 179 (4237), 321 (1988), that is, the reaction of a polyhydric alcohol or polyhydric phenol with acetylene, or They can be synthesized by the reaction of a polyhydric alcohol or polyhydric phenol and a halogenated alkyl vinyl ether, and these can be used singly or in combination of two or more.

  Moreover, a styrene derivative can also be employ | adopted as a polymerizable monomer used by this invention. Examples of styrene derivatives include styrene, p-methylstyrene, p-methoxystyrene, β-methylstyrene, p-methyl-β-methylstyrene, α-methylstyrene, p-methoxy-β-methylstyrene, p-hydroxy. Examples include styrene.

  In addition, trifluoroethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, (perfluorobutyl) ethyl (meth) acrylate, perfluorobutyl-hydroxypropyl ( Use compounds containing fluorine atoms such as (meth) acrylate, (perfluorohexyl) ethyl (meth) acrylate, octafluoropentyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, etc. Can do.

  Propenyl ether and butenyl ether can also be used as the polymerizable monomer used in the present invention. Examples of the propenyl ether or butenyl ether include 1-dodecyl-1-propenyl ether, 1-dodecyl-1-butenyl ether, 1-butenoxymethyl-2-norbornene, 1-4-di (1-butenoxy) butane, 1,10-di (1-butenoxy) decane, 1,4-di (1-butenoxymethyl) cyclohexane, diethylene glycol di (1-butenyl) ether, 1,2,3-tri (1-butenoxy) propane, propenyl ether propylene Carbonate or the like can be suitably applied.

The polymerizable monomer in the present invention is preferably contained in the component excluding the solvent in the composition in a range of 70 to 99.5% by mass, and more preferably in a range of 90 to 99% by mass.
Furthermore, it is preferable that the polymerizable monomer having a radical polymerizable group is contained in an amount of 50% by mass or more, more preferably 80% by mass or more in the total polymerizable monomers.

Next, a preferable blend form of polymerizable monomers (hereinafter, these may be collectively referred to as “polymerizable unsaturated monomers”) will be described.
A monofunctional polymerizable unsaturated monomer is usually used as a reactive diluent and is effective in lowering the viscosity of the photocurable composition. A monomer having two unsaturated bond-containing groups (bifunctional polymerizable unsaturated monomer) has a moderate viscosity and has better photocuring ability than a monofunctional polymerizable unsaturated monomer. is there. A polyfunctional polymerizable unsaturated monomer having three or more unsaturated bond-containing groups has high viscosity, but is excellent in photocurability, and the resulting cured film has high film strength. These monomers are mixed and used according to the purpose. As a preferable blending mode, the monofunctional polymerizable unsaturated monomer is 0 to 80% by mass based on the total amount of all polymerizable monomers. , More preferably 0 to 50% by mass, bifunctional polymerizable unsaturated monomer is 10 to 100% by mass, more preferably 20 to 80% by mass, polyfunctional polymerizable unsaturated monomer is 10 to 70% by mass. More preferably, it is 20-50 mass%.

  The photocurable composition in the present invention may further contain a resin component for the purpose of improving dry etching resistance, imprint suitability, curability and the like. As the resin component, a resin having a polymerizable functional group in the side chain is preferable.

-Photopolymerization initiator-
The photocurable composition in the present invention preferably contains a photopolymerization initiator. As the photopolymerization initiator used in the present invention, any photopolymerization initiator can be used as long as it is a compound that generates an active species that polymerizes the above polymerizable monomer by light irradiation. The photopolymerization initiator is preferably a radical polymerization initiator that generates radicals by light irradiation, or a cationic polymerization initiator that generates acids by light irradiation, more preferably a radical polymerization initiator. It is determined appropriately according to the type of the polymerizable group. That is, the photopolymerization initiator in the present invention is formulated with an activity with respect to the wavelength of the light source to be used, and generates appropriate active species according to the difference in the reaction format (for example, radical polymerization or cationic polymerization). It is necessary to use something. In the present invention, a plurality of photopolymerization initiators may be used in combination.

Content of the photoinitiator used for this invention is 0.01-15 mass% in all the compositions except a solvent, for example, Preferably it is 0.1-12 mass%, More preferably, it is 0. 2 to 7% by mass. When using 2 or more types of photoinitiators, the total amount becomes the said range.
When the content of the photopolymerization initiator is 0.01% by mass or more, the sensitivity (fast curability), resolution, line edge roughness, and coating strength tend to be improved, which is preferable. On the other hand, when the content of the photopolymerization initiator is 15% by mass or less, light transmittance, colorability, handleability and the like tend to be improved, which is preferable. Until now, various addition amounts of preferred photopolymerization initiators and / or photoacid generators have been studied for ink-jet compositions and dye- and / or pigment-containing liquid crystal display color filter compositions. A preferred photopolymerization initiator and / or photoacid generator addition amount for the curable composition for photo nanoimprint lithography is not reported. That is, in a system containing dyes and / or pigments, these may act as radical trapping agents, affecting the photopolymerizability and sensitivity. In consideration of this point, the amount of the photopolymerization initiator added is optimized in these applications. On the other hand, in the photocurable composition of the present invention, dyes and / or pigments are not essential components, and the optimal range of the photopolymerization initiator is in the fields of inkjet compositions, liquid crystal display color filter compositions, and the like. May be different.

  As the radical photopolymerization initiator used in the present invention, acylphosphine compounds and oxime ester compounds are preferable from the viewpoints of curing sensitivity and absorption characteristics. As the photopolymerization initiator, for example, a commercially available initiator can be used. Examples of these include Irgacure® 2959 (1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, Irgacure (available from Ciba). (Registered trademark) 184 (1-hydroxycyclohexyl phenyl ketone), Irgacure (registered trademark) 500 (1-hydroxycyclohexyl phenyl ketone, benzophenone), Irgacure (registered trademark) 651 (2,2-dimethoxy-1,2-diphenylethane- 1-one), Irgacure® 369 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1), Irgacure® 907 (2-methyl-1 [4- Methylthiophenyl] -2-morpholinop Pan-1-one, Irgacure® 819 (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, Irgacure® 1800 (bis (2,6-dimethoxybenzoyl) -2,4 , 4-trimethyl-pentylphosphine oxide, 1-hydroxy-cyclohexyl-phenyl-ketone), Irgacure® 1800 (bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide) , 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one), Irgacure® OXE01 (1,2-octanedione, 1- [4- (phenylthio) phenyl] -2- ( O-benzoyloxime), Darocur (registered trader) Standard) 1173 (2-hydroxy-2-methyl-1-phenyl-1-propan-1-one), Darocur (R) 1116, 1398, 1174 and 1020, CGI242 (ethanone, 1- [9-ethyl-6 -(2-Methylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime), Lucirin TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide), Lucirin TPO available from BASF -L (2,4,6-trimethylbenzoylphenylethoxyphosphine oxide), ESACURE 1001M (1- [4-benzoylphenylsulfanyl] phenyl] -2-methyl-2- (4-methyl), available from ESACUR Nippon Siebel Hegner Phenylsulfur Phonyl) propan-1-one, N-1414 Adeka optomer (registered trademark) N-1414 (carbazole phenone) available from Asahi Denka Co., Adeka optomer (registered trademark) N-1717 (acridine), Adekaoptomer (registered trademark) N-1606 (triazine type), TFE-triazine (2- [2- (furan-2-yl) vinyl] -4,6-bis (trichloromethyl) -1 manufactured by Sanwa Chemical Co., Ltd.) , 3,5-triazine), TME-triazine (2- [2- (5-methylfuran-2-yl) vinyl] -4,6-bis (trichloromethyl) -1,3,5, manufactured by Sanwa Chemical Co., Ltd.) -Triazine), MP-triazine (2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine) manufactured by Sanwa Chemical, manufactured by Midori Chemical AZ-113 (2- [2- (3,4-dimethoxyphenyl) ethenyl] -4,6-bis (trichloromethyl) -1,3,5-triazine), TAZ-108 (2- (3 , 4-dimethoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine), benzophenone, 4,4'-bisdiethylaminobenzophenone, methyl-2-benzophenone, 4-benzoyl-4'- Methyl diphenyl sulfide, 4-phenylbenzophenone, ethyl Michler's ketone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 1-chloro-4-propoxythioxanthone, 2-methylthioxanthone, thioxa Ton ammonium salt, benzoin, 4,4'-dimethoxybenzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, 1,1,1-trichloroacetophenone, diethoxyacetophenone and dibenzosuberone , Methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoyldiphenyl ether, 1,4-benzoylbenzene, benzyl, 10-butyl-2-chloroacridone, [4- (methylphenylthio) Phenyl] phenylmethane), 2-ethylanthraquinone, 2,2-bis (2-chlorophenyl) 4,5,4 ', 5'-tetrakis (3,4,5-trimethoxyphenyl) 1 2′-biimidazole, 2,2-bis (o-chlorophenyl) 4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole, tris (4-dimethylaminophenyl) methane, ethyl-4 -(Dimethylamino) benzoate, 2- (dimethylamino) ethyl benzoate, butoxyethyl-4- (dimethylamino) benzoate, and the like.

  The photopolymerization initiator used in the present invention is formulated with an activity with respect to the wavelength of the light source to be used, and generates appropriate active species according to the difference in the reaction format (for example, radical polymerization or cationic polymerization). It is necessary to use something. A plurality of the photopolymerization initiators may be used.

  In the present invention, “light” includes not only light having a wavelength in the ultraviolet, near-ultraviolet, far-ultraviolet, visible, infrared, etc., or electromagnetic waves, but also radiation. Examples of the radiation include microwaves, electron beams, EUV, and X-rays. Laser light such as a 248 nm excimer laser, a 193 nm excimer laser, and a 172 nm excimer laser can also be used. The light may be monochromatic light (single wavelength light) that has passed through an optical filter, or may be light with a plurality of different wavelengths (composite light). The exposure can be multiple exposure, and the entire surface can be exposed after forming a pattern for the purpose of increasing the film strength and etching resistance.

  The photopolymerization initiator used in the present invention needs to be selected in a timely manner with respect to the wavelength of the light source to be used, but is preferably one that does not generate gas during mold pressurization / exposure. When the gas is generated, the mold is contaminated, so that the mold has to be frequently washed, and the photocurable composition is deformed in the mold, resulting in deterioration of the transfer pattern accuracy.

  The photocurable composition in the present invention is a photoradical curable composition in which the polymerizable monomer is a radical polymerizable monomer, and the photopolymerization initiator is a radical polymerization initiator that generates radicals by light irradiation. It is preferable that it is a thing.

-Other components-
The nanoimprint curable composition of the present invention includes a surfactant, an antioxidant, and an antioxidant, as long as the effects of the present invention are not impaired, according to various purposes in addition to the above-described polymerizable monomer and photopolymerization initiator. Other components such as a solvent and a polymer component may be included.

  The photocurable composition in the present invention preferably contains a surfactant. The content of the surfactant used in the present invention is, for example, 0.001 to 5% by mass, preferably 0.002 to 4% by mass, and more preferably 0.005 to 3% in the entire composition. % By mass. When using 2 or more types of surfactant, the total amount becomes the said range. When the surfactant is in the range of 0.001 to 5% by mass in the composition, the effect of coating uniformity is good, and deterioration of mold transfer characteristics due to excessive surfactant is unlikely to occur.

The surfactant preferably includes at least one of a fluorine-based surfactant, a silicone-based surfactant, and a fluorine / silicone-based surfactant, and both a fluorine-based surfactant and a silicone-based surfactant or More preferably, it contains a fluorine / silicone surfactant, and most preferably contains a fluorine / silicone surfactant.
Here, the fluorine / silicone surfactant refers to one having both requirements of a fluorine surfactant and a silicone surfactant.

  By using such a surfactant, the photocurable composition according to the present invention can be applied to a silicon wafer for manufacturing a semiconductor device, a glass square substrate for manufacturing a liquid crystal device, a chromium film, a molybdenum film, a molybdenum alloy film, or tantalum. Striations and scales that occur during coating, such as various films, such as films, tantalum alloy films, silicon nitride films, amorphous silicone films, tin oxide-doped indium oxide (ITO) films and tin oxide films It is possible to solve the problem of coating defects such as patterns (unevenness of drying of resist film). Also, improve the fluidity of the composition into the cavity of the mold recess, improve the peelability between the mold and the resist, improve the adhesion between the resist and the substrate, reduce the viscosity of the composition, etc. Is possible. In particular, in the photocurable composition according to the present invention, the coating uniformity can be greatly improved by adding the surfactant, and the coating using a spin coater or slit scan coater is good regardless of the substrate size. Application suitability is obtained.

Examples of nonionic fluorosurfactants that can be used in the present invention include trade names Fluorard FC-430 and FC-431 (manufactured by Sumitomo 3M Co., Ltd.), trade names Surflon S-382 (Asahi Glass ( EFTOP EF-122A, 122B, 122C, EF-121, EF-126, EF-127, MF-100 (manufactured by Tochem Products), trade names PF-636, PF-6320, PF -656, PF-6520 (all OMNOVA Solutions, Inc.), trade names FT250, FT251, DFX18 (all manufactured by Neos), trade names Unidyne DS-401, DS-403, DS-451 ( (All are Daikin Industries, Ltd.), trade names Megafuk 171, 172, 173, 178K, 178A (all Dainippon Ink Chemical Kogyo Co., Ltd.).
Examples of the nonionic silicone surfactant include trade name SI-10 series (manufactured by Takemoto Yushi Co., Ltd.), MegaFac Paintad 31 (manufactured by Dainippon Ink & Chemicals, Inc.), KP -341 (manufactured by Shin-Etsu Chemical Co., Ltd.).
Examples of the fluorine / silicone surfactant include trade names X-70-090, X-70-091, X-70-092, X-70-093 (all Shin-Etsu Chemical Co., Ltd. )), And trade names Megafuk R-08 and XRB-4 (both manufactured by Dainippon Ink & Chemicals, Inc.).

Furthermore, the photocurable composition in the present invention preferably contains a known antioxidant. Content of the antioxidant used for this invention is 0.01-10 mass% in all the compositions except a solvent, for example, Preferably it is 0.2-5 mass%. When using 2 or more types of antioxidant, the total amount becomes the said range.
The antioxidant suppresses fading caused by heat or light irradiation and fading caused by various oxidizing gases such as ozone, active oxygen, NO _x , SO _x (X is an integer). In particular, in the present invention, the addition of an antioxidant has an advantage that the cured film can be prevented from being colored, or the film thickness reduction due to decomposition can be reduced. Examples of such antioxidants include hydrazides, hindered amine antioxidants, nitrogen-containing heterocyclic mercapto compounds, thioether antioxidants, hindered phenol antioxidants, ascorbic acids, zinc sulfate, thiocyanates, Examples include thiourea derivatives, sugars, nitrites, sulfites, thiosulfates, hydroxylamine derivatives, and the like. Among these, hindered phenol antioxidants and thioether antioxidants are particularly preferable from the viewpoint of coloring the cured film and reducing the film thickness.

  Commercially available products of the antioxidant include trade names Irganox 1010, 1035, 1076, 1222 (manufactured by Ciba Geigy Co., Ltd.), trade names Antigene P, 3C, FR, Sumilyzer S, Sumilyzer GA80 (Sumitomo Chemical Co., Ltd.) Product name) ADK STAB AO70, AO80, AO503 (manufactured by ADEKA Corporation) and the like. These may be used alone or in combination.

In addition to the above components, the photocurable composition in the present invention may contain a solvent as necessary. In particular, a solvent is preferably contained when forming a pattern having a thickness of 500 nm or less. A preferable solvent is a solvent having a boiling point of 80 to 200 ° C. at normal pressure. Any solvent can be used as long as it can dissolve the composition, but a solvent having any one or more of an ester structure, a ketone structure, a hydroxyl group, and an ether structure is preferable.
Preferred solvents are propylene glycol monomethyl ether acetate, cyclohexanone, 2-heptanone, gamma butyrolactone, propylene glycol monomethyl ether, ethyl lactate alone or mixed solvents, and a solvent containing propylene glycol monomethyl ether acetate is used for coating uniformity. Most preferable from the viewpoint.

  In addition to the above components, the photocurable composition in the present invention may include a release agent, a silane coupling agent, a polymerization inhibitor, an ultraviolet absorber, a light stabilizer, an antiaging agent, a plasticizer, and an adhesion promoter. , Thermal polymerization initiators, colorants, elastomer particles, photoacid proliferators, photobase generators, basic compounds, flow regulators, antifoaming agents, dispersants and the like may be added.

The viscosity at 25 ° C. of the component excluding the solvent of the photocurable composition used in the pattern forming method of the present invention is preferably 5 to 2000 mPa · s, more preferably 7 to 1000 mPa · s, still more preferably 8 to. 500 mPa · s, most preferably 10 to 100 mPa · s.
If the viscosity is a solvent-free cured composition, the viscosity of the composition itself at 25 ° C. can be used, and if it is a cured composition containing a solvent, the composition excluding the solvent is separately adjusted, Viscosity can be used.
Moreover, it is preferable that the photocurable composition used by the pattern formation method of this invention designs a composition so that a viscosity may be 1-100 mPa * s in the temperature (X) in the crimping | compression-bonding process mentioned later. Generally, the viscosity of the composition can be adjusted by blending various monomers, oligomers and polymers having different viscosities.

  When the solvent is contained in the photocurable composition in this invention, the process of heating a photocurable composition and removing a solvent may be included in the provision process in this invention as needed. The heating temperature in this step can be appropriately set according to the solvent contained in the composition.

[Crimping process: Process 2]
The crimping | compression-bonding process in this invention is a process of crimping | bonding a mold to the said photocurable composition provided on the said base material. Moreover, in the pattern formation method of this invention, the temperature (X) of the said photocurable composition in the said crimping | compression-bonding process is 30 degreeC or more. In the press-bonding step in the present invention, when the temperature (X) of the photo-curable composition is less than 30 ° C., the filling property of the photo-curable composition into the mold is lowered during the press-bonding, and the pattern shape is deteriorated. Moreover, the temperature (X) of the said photocurable composition should just be 30 degreeC or more for a moment during the crimping | compression-bonding process in this invention. That is, when the mold and the photocurable composition are in contact with each other, the pressure (X) is less than 30 ° C. and may be pressure-bonded while being heated to 30 ° C. or higher, or the mold may be pressure-bonded after being heated to 30 ° C. or higher. . Moreover, the crimping | compression-bonding process in this invention has the process of heating the said photocurable composition provided on the base material in order to make temperature (X) of the said photocurable composition 30 degreeC or more. May be. Furthermore, the pressure-bonding step in the present invention preferably includes a step of cooling so that the temperature of the photocurable composition is less than 30 ° C. before the photocuring step (step 3) described later.

  In the pattern formation method of this invention, you may perform an application | coating process (process 1) and a crimping | compression-bonding process (process 2) simultaneously. For example, the cured composition can be filled between the substrate and the mold by placing the substrate and the mold so as to face each other and bringing the cured composition into contact between the substrate and the mold.

  The means for setting the temperature (X) of the photocurable composition in the pressure-bonding step in the present invention to 30 ° C. or higher is not particularly limited. For example, the photocurable composition may be heated in the pressure-bonding step, The photocurable composition may be heated in advance. In the pattern formation method of this invention, it is preferable to include especially the heating process which heats the photocurable composition provided on the base material. A heating method in the heating step is not particularly limited, but it is preferable to heat a substrate such as a substrate or a support, a mold, an apparatus, or a plurality of these by a heating apparatus such as a heater. Also in this case, productivity is improved by preheating the photocurable composition.

The preferable range of the temperature (X) of the photocurable composition in the pressure-bonding step is 30 to 150 ° C, preferably 30 to 100 ° C, more preferably 30 to 80 ° C, and particularly preferably 40 to 60 ° C. By making temperature (X) into an appropriate range, pattern formation property improves, thermal polymerization of a hardening composition can be suppressed, and pattern accuracy improves further.
The temperature (X) of the photocurable composition is preferably a temperature at which the viscosity of the photocurable composition on the substrate before mold pressing is 1 to 100 mPa · s, more preferably 1 to 60 mPa. S, more preferably 1 to 30 mPa · s, most preferably 1 to 10 mPa · s. As for the viscosity of the photocurable composition on the substrate before the pressure bonding of the mold, in the case of the photocurable composition containing no solvent, the viscosity at the temperature (X) of the photocurable composition can be used as a standard. it can. When a solvent is contained in the photocurable composition and the solvent is removed by heating in the application step, a photocurable composition excluding the solvent is prepared separately, and the viscosity of the composition at the temperature (X) is adjusted. Can be used as a reference.

  The molding material that can be used in the present invention will be described. In the optical nanoimprint lithography using the photocurable composition in the present invention, it is necessary to select a light transmissive material for at least one of the molding material and / or the base material. In the photoimprint lithography applied to the present invention, a photocurable composition is applied on a substrate in the application step, a light-transmitting mold is pressed in the main pressure bonding step, and the mold is formed in the photocuring step described later. Light is irradiated from the back surface to cure the photocurable composition. Moreover, a photocurable composition is apply | coated on a transparent base material, a mold is pressed, light is irradiated from the back surface of a mold, and the curable composition for optical nanoimprint lithography can also be hardened.

As the mold that can be used in the present invention, a mold having a pattern to be transferred is used. The mold can form a pattern according to the desired processing accuracy by, for example, photolithography, electron beam drawing, or the like, but the mold pattern forming method is not particularly limited in the present invention.
The light-transmitting mold material used in the present invention is not particularly limited as long as it has predetermined strength and durability. Specifically, a light transparent resin such as glass, quartz, PMMA, and polycarbonate resin, a transparent metal vapor-deposited film, a flexible film such as polydimethylsiloxane, a photocured film, and a metal film are exemplified. The mold shape may be a plate shape or a curved shape (for example, a roll shape).

  In the pattern forming method of the present invention, the non-light transmission mold material used when a transparent substrate is used is not particularly limited as long as it has a predetermined strength. Specific examples include ceramic materials, deposited films, magnetic films, reflective films, metal substrates such as Ni, Cu, Cr, and Fe, and substrates such as SiC, silicone, silicone nitride, polysilicon, silicone oxide, and amorphous silicone. There are no particular restrictions. The shape may be either a plate mold or a roll mold. The roll mold is applied particularly when continuous transfer productivity is required.

  As the mold used in the present invention, it is preferable to use a mold which has been subjected to a release treatment in order to improve the peelability between the photocurable composition and the mold. Examples of the mold release treatment include those treated with a silane coupling agent such as silicone or fluorine, for example, Daikin Industries, Optool DSX, Sumitomo 3M, Novec EGC-1720, and other commercially available mold release agents, fluorine A method of vapor-depositing a system compound can also be suitably used.

  In the case of performing photoimprint lithography using the present invention, the conditions for pressure bonding the mold to the photocurable composition are as follows: the mold pressure is 10 atm (about 1.0133 MPa) or less, preferably 5 atm (about 0.50665 MPa). ) Hereinafter, it is more preferable to carry out at 1 to 2 atm (about 0.10133 to 0.20266 MPa). By setting the mold pressure to 10 atm or less, the mold and the substrate are hardly deformed. Further, the pattern accuracy can be improved, and the durability of the mold is also improved. Further, it is preferable from the viewpoint that the apparatus can be reduced because the pressure is low. As the mold pressure, it is preferable to select a region in which the uniformity of mold transfer can be ensured within a range in which the remaining film of the curable composition for optical nanoimprinting on the mold convex portion is reduced.

[Photocuring step: Step 3]
The photocuring step in the present invention is a step of photocuring the photocurable composition to form a reversal pattern of the mold. In the photocuring step, the mold and the photocurable composition are irradiated with light in a pressure-bonded state, and the photocurable composition is photocured to transfer the mold pattern to the photocurable composition. Can be formed.

  The light used for curing the photocurable composition in the present invention is not particularly limited. For example, light having a wavelength in the region of high energy ionizing radiation, near ultraviolet, far ultraviolet, visible, infrared, or the like. Or radiation is mentioned. As the high-energy ionizing radiation source, for example, an electron beam accelerated by an accelerator such as a cockcroft accelerator, a hand-graff accelerator, a linear accelerator, a betatron, or a cyclotron is industrially most conveniently and economically used. In addition, radiation such as γ-rays, X-rays, α-rays, neutrons, and protons emitted from radioisotopes and nuclear reactors can also be used. Examples of the ultraviolet ray source include an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a carbon arc lamp, and a solar lamp. The radiation includes, for example, microwaves and EUV. Also, laser light used in semiconductor microfabrication such as LED, semiconductor laser light, or 248 nm KrF excimer laser light or 193 nm ArF excimer laser can be suitably used in the present invention. These lights may be monochromatic lights, or may be lights having different wavelengths (mixed lights).

During exposure is preferably in the range of exposure intensity of ^{1mW / cm 2 ~50mW / cm 2} . By making the exposure time 1 mW / cm ² or more, the exposure time can be shortened so that productivity is improved, and by making the exposure time 50 mW / cm ² or less, deterioration of the properties of the permanent film due to side reactions can be suppressed. It tends to be preferable. The exposure dose is desirably in the range of 5 mJ / cm ^{2 to} 1000 mJ / cm ² . If it is less than 5 mJ / cm ² , the exposure margin becomes narrow, photocuring becomes insufficient, and problems such as adhesion of unreacted substances to the mold tend to occur. On the other hand, if it exceeds 1000 mJ / cm ² , the permanent film may be deteriorated due to decomposition of the composition.

  The temperature in the photocuring step may be the temperature set in the pressure bonding step (step 2), or may be cooled in this step, but the temperature set in the pressure bonding step is the production. From the viewpoint of sex.

Further, during exposure, in order to prevent inhibition of radical polymerization by oxygen, an inert gas such as nitrogen or argon may be flowed to control the oxygen concentration to less than 100 mg / L. Moreover, you may irradiate light in a vacuum state. In the present invention, the preferable degree of vacuum is 10 ⁻¹ Pa to normal pressure.

  As the pattern to be formed becomes finer, it becomes more difficult to achieve good pattern formability. However, since the pattern forming method of the present invention can exhibit good pattern accuracy, it exhibits a particularly remarkable effect when forming a pattern containing a pattern having a minimum dimension of 1 nm to 50 μm. The pattern preferably formed by the pattern forming method of the present invention is a pattern containing a pattern having a minimum dimension of 1 nm to 20 μm, more preferably 1 nm to 1 μm, still more preferably 1 nm to 500 nm, and most preferably 1 nm to 200 nm. It contains a pattern. As described above, the finer the pattern, the more remarkable the effect of the present invention.

  In the pattern formation method of this invention, after making a pattern formation layer harden | cure by light irradiation, the process of applying the heat | fever to the pattern hardened | cured as needed may be included. As heat which heat-hardens the composition of this invention after light irradiation, 150-280 degreeC is preferable and 200-250 degreeC is more preferable. In addition, the time for applying heat is preferably 5 to 60 minutes, and more preferably 15 to 45 minutes.

  As the most preferred embodiment of the present invention, a photocurable composition having a viscosity of 5 to 2000 mPa · s at 25 ° C. of the components excluding the solvent is used, and at least in the pressure-bonding step (step 2), the photocurable property on the substrate is used. This is a mode including a step of setting the temperature (X) of the photocurable composition on the substrate to 30 to 150 ° C. so that the viscosity of the composition becomes 1 to 100 mPa · s.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[Preparation of Photocurable Composition]
Photopolymerization initiator P-1 (2% by mass), surfactant W-1 (0.1% by mass), surfactant W-2 (0.04% by mass) ) And antioxidants A-1 and A-2 (each 1% by mass) were added to prepare a photocurable composition. Table 2 below shows the viscosity at 25 ° C. and the viscosity at the temperature (X) of the compositions of the examples and comparative examples.

＜重合性単量体＞
Ｒ１：ネオペンチルグリコールジアクリレート
Ｒ２：トリメチロールプロパントリアクリレート（アロニックスＭ−３０９：東亞合成（株）製）
Ｒ３：ペンタエリスリトールテトラアクリレート（Ａｌｄｒｉｃｈ社製）
＜光重合開始剤＞
Ｐ−１：２，４，６−トリメチルベンゾイル−エトキシフェニル−ホスフィンオキシド（Ｌｕｃｉｒｉｎ ＴＰＯ−Ｌ：ＢＡＳＦ社製）

<Polymerizable monomer>
R1: Neopentyl glycol diacrylate R2: Trimethylolpropane triacrylate (Aronix M-309: manufactured by Toagosei Co., Ltd.)
R3: Pentaerythritol tetraacrylate (manufactured by Aldrich)
<Photopolymerization initiator>
P-1: 2,4,6-trimethylbenzoyl-ethoxyphenyl-phosphine oxide (Lucirin TPO-L: manufactured by BASF)

<Surfactant>
W-1: Fluorosurfactant (manufactured by Tochem Products Co., Ltd .: Fluorosurfactant)
W-2: Silicone surfactant (manufactured by Dainippon Ink and Chemicals, Inc .: MegaFuck Paint 31)

<Antioxidant>
A-1: Sumilizer GA80 (manufactured by Sumitomo Chemical Co., Ltd.)
A-2: ADK STAB AO503 (manufactured by ADEKA Corporation)

(Evaluation)
The following evaluation was performed about the obtained composition. The results are shown in Table 2 below.

<Pattern formability / residual film>
Each composition was spin-coated on a silicon substrate so as to have a film thickness of 150 nm. Those having a high viscosity were dissolved in propylene glycol monomethyl ether acetate and dried by heating at 100 ° C. for 60 seconds after spin coating. The obtained coating film was placed in a nanoimprint apparatus with a mold having a pattern surface made of quartz having a 200 nm line / space pattern and a groove depth of 200 nm made of quartz as a material. The inside of the apparatus was evacuated and then purged with nitrogen to replace the inside of the apparatus with nitrogen. The mold is pressure-bonded to the substrate at the temperature (X) shown in Table 2 below at a pressure of 1.5 atm, and exposed to this at 240 mJ / cm ² from the back surface of the mold. After exposure, the mold is released to obtain a pattern. It was. In the comparative example, a pattern was formed in the same manner as in the example except that the same composition as in the example was used and the temperature (X) was 25 ° C.
The obtained pattern was observed with SEM, and the pattern shape and the remaining film were evaluated according to the following criteria.

(Pattern shape)
A: A rectangular pattern faithful to the mold pattern.
B: The pattern top was rounded.
C: The pattern top was rounded and the pattern height was insufficient.

(Residual film)
The remaining film was evaluated by measuring the height Y of the remaining film of the pattern 2 formed on the substrate 1 as shown in FIG.
A: Less than 20 nm B: 20 nm or more and less than 50 nm C: 50 nm or more

<Pencil hardness>
In order to eliminate the influence of the substrate, the pencil hardness was measured under thick film conditions. Each composition was spin-coated on a silicon substrate so as to have a film thickness of 4 μm. Those having a high viscosity were dissolved in propylene glycol monomethyl ether acetate and dried by heating at 100 ° C. for 60 seconds after spin coating. The obtained coating film was exposed under the condition of 240 mJ / cm ² without placing a mold in a nitrogen atmosphere to obtain a cured film. The pencil hardness of the obtained cured film was measured by a method based on “JIS K5600-5-4”. The larger the number, the higher the pencil hardness, which is desirable.

As can be seen from Table 2, it can be seen that the pattern produced by the pattern forming method of the present invention has excellent pattern formability and a pencil hardness of 3H or more. On the other hand, the pattern formed by the method of the comparative example (the temperature (X) of the composition in the pressure bonding step is 25 ° C.) is often high in viscosity and inferior in pattern formability. In particular, by comparing each example and comparative example, if the temperature (X) during the crimping process is 30 ° C. or higher, pattern formation is performed as compared with the case where all the conditions are the same except that the temperature (X) is 25 ° C. or higher. It can be seen that the property is improved and the remaining film is also improved.
As described above, the pattern formation method of the present invention shows good pattern formability even when the pressure at the time of mold pressing is low by setting the temperature (X) at the time of mold pressing to 30 ° C. or higher, and has a higher film hardness. Can be compatible.

It is explanatory drawing for showing the residual film of a pattern.

Explanation of symbols

1 substrate 2 pattern

Claims (9)

An application step of applying the photocurable composition onto the substrate;
A pressure-bonding step in which a mold is pressure-bonded to the photocurable composition applied on the substrate;
A photocuring step of photocuring the photocurable composition to form a reversal pattern of the mold;
In the photocurable composition, the content of the component having a molecular weight of 1000 or more with respect to all components excluding the solvent is 30% by mass or less, and the temperature (X) of the photocurable composition in the compression bonding step Is a pattern forming method, wherein the temperature is 30 ° C. or higher.   The pattern forming method according to claim 1, wherein the applying step includes a step of removing the solvent by heating the photocurable composition.   The pattern forming method according to claim 1, wherein the pressure-bonding step includes a step of heating the photocurable composition applied on the base material.   The pattern forming method according to claim 1 or 2, wherein the viscosity of the component excluding the solvent of the photocurable composition at 25 ° C is 5 to 2000 mPa · s.   The temperature (X) of the photocurable composition is such that the viscosity of the photocurable composition applied on the substrate is 1 to 100 mPa.s. The pattern forming method according to claim 1, wherein the temperature is s.   The pattern forming method according to claim 1, wherein the pattern formed in the photocuring step contains a pattern having a minimum dimension of 1 nm to 50 μm.   The pattern forming method according to any one of claims 1 to 6, wherein in the pressure bonding step, the mold is pressure bonded to the photocurable composition at a pressure of 0.1 MPa to 1 MPa.   The temperature (X) of the said photocurable composition is 30 to 150 degreeC, The pattern formation method of any one of Claims 1-7 characterized by the above-mentioned.   The said photocurable composition contains a polymerizable monomer and a photoinitiator, The pattern formation method of any one of Claims 1-8 characterized by the above-mentioned.

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