JP2016096291A - Curable composition for imprint, and method for manufacturing resist laminate by use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a curable composition for imprint, which includes a polymerizable monomer hard to permeate a polydimethylsiloxane mold; and a method for manufacturing a resist laminate by use of such a composition.SOLUTION: A curable composition for imprint comprises: a polymerizable monomer of which the polarization term (dP) in Hansen parameters (HSP) is 4.0 or more, or the molecular size is equal to or larger than a PDMS micropore size of 0.70 nm. The polymerizable monomer is hard to permeate PDMS. Use of the curable composition including polymerizable components made of the polymerizable monomers enables the suppression of the permeation into PDMS mold.SELECTED DRAWING: None

Description

  The present invention relates to a curable composition for imprints and a method for producing a resist laminate using the composition.

  In recent years, high-precision semiconductor integrated circuits that have been miniaturized by microfabrication have been produced. In addition to high-precision semiconductor integrated circuits, microfabrication is used for optical / illumination applications such as the formation of antireflection layers such as liquid crystal panels, and the improvement of light extraction efficiency in polarizing films, organic EL panels, and LED (Light emitting diode) substrates. This is a necessary technology for water repellent processing of automotive window glass, biotechnology such as three-dimensional cell culture technology, and energy development of secondary batteries, solar cells, fuel cells and the like. As one of such fine processing methods, nanoimprint technology is used.

  With nanoimprint technology, a mold having pattern irregularities corresponding to the pattern to be formed on the substrate is embossed on the coating film formed on the substrate surface, and the coating film is cured and then separated (released). Thus, the method includes a step of transferring a desired pattern onto the surface of the substrate, and is expected as a fine processing technique that can be mass-produced at low cost.

  This nanoimprint technology is roughly classified into two types depending on the characteristics of the coating material formed on the substrate surface. The first is to use a thermoplastic resin as the coating material, heat it to a temperature above the glass transition temperature, plastically deform it, press the mold, and then cool it down to cure the coating material to transfer the pattern. Imprint method.

  The other uses at least one of a mold and a substrate, uses a liquid photocurable composition as a coating material, presses the mold into contact with the coating, and then molds or the substrate Is a photoimprinting method in which a pattern is transferred by irradiating light through a film to cure the coating material.

  The thermal nanoimprint method has a problem that it has a low throughput, a dimensional change due to temperature, and a decrease in pattern accuracy because of a thermal cycle of heating and cooling. On the other hand, the optical imprint method is excellent in throughput because there is no thermal cycle, and the dimensional change due to temperature is small. For this reason, the photoimprint method is widely used in nanoimprint technology, and development of a photocurable composition for imprints suitably used for the method is underway.

  As a mold used for imprinting, a replica mold obtained by replicating a master mold produced by electron beam drawing on a quartz glass or a silicon substrate is generally used. This is because the master mold (original) is very expensive and minimizes the risk of breakage and the like.

  The optical imprint method is classified into two types, a decompression method and a normal pressure method, depending on the pressure environment during imprinting. The decompression method is a method in which the inside of the chamber is decompressed to release air, the mold is pressed under reduced pressure, and the pattern is transferred (see FIG. 1). For the replica mold, a resin film mold such as polyethylene terephthalate (PET) or cyclic polyolefin resin (COP) is often used. On the other hand, the normal pressure method is a method in which a mold is pressed in air to transfer a pattern (see FIG. 2). For the replica mold, it is essential to use a silicone resin, for example, a polydimethylsiloxane (PDMS) mold. In the normal pressure method (see FIG. 3), since imprinting is performed in air, air always enters the mold during imprinting. PDMS has an extremely high gas permeability of 10 to 100 times that of ordinary plastics, so that air that has entered through the mold can be removed (see FIGS. 3a and b). Therefore, there is no pattern defect even in the air, and pattern transfer can be performed (see FIG. 3c).

  PDMS has a helical structure in which the siloxane chain has a methyl group outside, so that air can easily pass through the pores. Therefore, it is possible to carry out mold pressing on the coating film in the air, but on the other hand, oxygen is easily supplied to the coating during light irradiation, so a radical polymerization type curable composition for imprints is used. In this case, polymerization inhibition occurs. Therefore, when the PSMS mold is used in the air, it is preferable to use a photopolymerizable composition for imprinting of a cationic polymerization system that does not undergo polymerization inhibition. When using a photopolymerizable composition for imprinting based on radical polymerization, it can be cured without problems if it is controlled in an atmosphere free of oxygen, such as under nitrogen, argon or vacuum. The usage method of the PDMS mold at the time of imprinting is the same as that of other replica molds such as quartz, and imprinting can be performed using a known curable composition for imprinting (for example, Patent Documents). 1).

JP 2013-189537 A

  Usually, the PDMS mold is used repeatedly. In that case, the curable composition for imprints and the deposit of the cured body of the composition sometimes adhered and deteriorated. These deposits may be reduced or removed by washing or the like. However, according to the study by the present inventors, it has been found that there are factors other than these deposits that degrade the PDMS mold. That is, if it is a deposit | attachment of the curable composition for imprints, it can confirm with a microscope etc., but according to examination of the present inventors, the PDMS mold was made to contact with the coating film which consists of a curable composition for imprints. At this time, when the curable composition for imprints penetrates into the pores of PDMS, the gas permeability is lowered and the mold is swelled. As a result, the dimensional change of the mold pattern, the occurrence of defects, the release property It was found that a decrease occurred. Therefore, when using a PDMS mold, it turned out that the curable composition for imprint which does not penetrate | penetrate PDMS from the point which suppresses the deterioration by the increase in the number of times of repeated use of a mold is required.

  Accordingly, an object of the present invention is to provide a curable composition for imprints composed of a polymerizable monomer that hardly penetrates into a PDMS mold, and a method for producing a resist laminate using the composition.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. And it was found that the causative substance that penetrates into PDMS and decreases gas permeability etc. is a polymerizable monomer component (the organic solvent used for the coating agent is used repeatedly in PDMS molds) Sometimes it has been found that it does not degrade its performance.) As a result of examining the polymerizable monomer that is difficult to penetrate into the PDMS mold, the polarization term (dP) in the Hansen solubility parameter (HSP) of the polymerizable monomer exceeds a specific value, or the molecular size It has been found that the above-mentioned problems can be solved by using a curable composition for imprints containing a polymerizable component comprising a polymerizable monomer having a specific size or more, and the present invention has been completed.

That is, the first aspect of the present invention is a curable composition for imprints used when imprinting is performed using a mold made of polydimethylsiloxane, and includes at least one of the following requirements (1) and (2): A curable composition for imprints comprising a polymerizable component composed of a polymerizable monomer satisfying the above.
(1) The polarization term (dP) of the Hansen solubility parameter (HSP) is 4.0 or more.
(2) The molecular size is 0.70 nm or more.

  Further, the second aspect of the present invention is a coating film forming step for applying a coating agent containing the curable composition for imprints on a substrate and forming a coating film comprising the composition, in the presence of oxygen, A pattern forming surface of a mold made of polydimethylsiloxane on which a pattern is formed and the coating film are brought into contact with each other, and in this state, the coating film is cured by irradiating light, and the mold is separated from the cured coating film And a pattern transfer step of forming a pattern corresponding to the pattern formed on the pattern forming surface of the mold on the substrate, to produce a resist laminate in which the pattern is formed on the base substrate. Is the method.

  Furthermore, in the third aspect of the present invention, after the resist laminate is manufactured by the above method, the pattern formation surface of the resist laminate is contacted with the etching gas using the pattern formed on the resist laminate as a mask. And a method of manufacturing a substrate on which a pattern is formed.

  In the imprint method using a PDMS mold, by using the curable composition for imprints of the present invention, penetration of the polymerizable monomer into PDMS is suppressed, and pattern defects can be prevented. It is possible to greatly increase the number of repeated uses.

Decompression method imprint flowchart Normal pressure imprint flow diagram Image of filling with normal pressure method

The present invention relates to a curable composition for imprints composed of a polymerizable monomer that hardly penetrates into a PDMS mold, and a method for producing a resist laminate using the composition.
In the following, description will be given in order. First, the curable composition for imprints is described.

(Curable composition for imprint)
The curable composition for imprints in the present invention is a polymerizable monomer satisfying specific requirements (the above requirements (1) or (2) or the requirements of both (1) and (2)). It comprises a polymerizable component comprising a body. That is, the polymerizable component contained in the curable composition for imprints is composed of a polymerizable monomer whose total amount satisfies at least one of the requirements (1) and (2). The polymerizable monomer satisfying at least one of the requirements (1) and (2) may be composed of one kind or plural kinds.

(Polymerizable component)
In the present invention, the polymerizable component corresponds to the main component of the curable composition for imprints, and as described above, the polymerizable monomer satisfying at least one of the requirements (1) and (2) Consists of.

  The polymerizable monomer satisfying any one of the requirements (1) and (2) is a polymerizable monomer having a known radical polymerizable group or cationic polymerizable group used for photopolymerization. Can be used. The radical polymerizable group is preferably a methacryl group or an acrylic group, and the cationic polymerizable group is preferably an epoxy group (oxirane group) or an oxetane group. Further, it may be a monofunctional polymerizable monomer having one polymerizable group in one molecule, or a polyfunctional polymerizable monomer having two or more polymerizable groups in one molecule. Also good. Furthermore, these monofunctional polymerizable monomers and polyfunctional polymerizable monomers can also be used in combination. A polymerizable monomer having a radical polymerizable group and a polymerizable monomer having a cationic polymerizable group can also be used in combination.

In the present invention, the polymerizable monomer constituting the polymerizable component must satisfy at least one of the following requirements (1) and (2).
(1) The polarization term (dP) of the Hansen solubility parameter (HSP) is 4.0 or more.
(2) The molecular size is 0.70 nm or more.

  The Hansen Solubility Parameter (HSP) of a polymerizable monomer is a solubility index that indicates how much a certain substance is soluble in a certain substance. The solubility is expressed as a multidimensional vector, and the vectors are similar. It is judged that the mutual solubility is high. This vector is represented by [dispersion term (dD), polarity term (dP), hydrogen bond term (dH)]. When calculating the Hansen solubility parameter, the structural formula is input to the HSP software and calculated. Specifically, it can be obtained by software developed by Charles Hansen et al. (Software name: Hansen Solubility Parameter in Practice (HSPIP) Version 4.1.03).

  The molecular size in the present invention is determined by inputting the structural formula of the polymerizable monomer into the software (software name: Chem Bio 3D Ultra Version 12.0), optimizing the structure with the AM1 method, and then outputting the MOPAC. In the MOLECULAR DIMENSIONS described in the file, the longest interatomic length in a plane perpendicular to the longest interatomic length direction is employed. In MOLECULAR DIMENSIONS, the longest interatomic length in the molecule, the length direction of the longest interatomic length in the molecule, or the length of the molecular size (interatomic length) employed in the present invention. The interatomic length that is the longest in the direction perpendicular to the vertical direction is shown. In the present invention, the longest interatomic length in the plane perpendicular to the longest interatomic length direction is adopted as the “molecular size” because the molecules of the polymerizable monomer can pass through. This is because it corresponds to the diameter of the smallest circle.

  The polymerizable monomer used in the curable composition for imprints may be composed of only a polymerizable monomer that satisfies at least one of the following requirements (1) to (2). Or two or more of them may be included.

Polymerizable monomer satisfying the requirement of (1) According to the study by the present inventors, in the penetration test into the PDMS mold described in detail in the examples, the polarization term of the Hansen solubility parameter (HSP) ( It has been found that a polymerizable monomer having a dP) of 4.0 or more, preferably 6.0 or more is difficult to penetrate into PDMS. This is because PDMS is (dD, dP, dH) = (12.3, 0.3, 0.4), and of these, the difference from the polarization term (dP) is the penetration of PDMS. It is considered that the penetration into PDMS is most influenced by the polarity of the polymerizable monomer. The upper limit value of the polarization term (dP) of the Hansen solubility parameter (HSP) of the polymerizable monomer is not particularly limited, but it is 20.0 or less in consideration of easiness of imprinting, curability and the like. It is.

  Specific examples of the polymerizable monomer satisfying the requirement (1) include methoxy-triethylene glycol acrylate (dP = 5.9), tetraethylene glycol diacrylate (dP = 6.1), tri Propylene glycol diacrylate (dP = 6.5), phenoxyethyl acrylate (dP = 5.4), phenoxydiethylene glycol acrylate (dP = 5.5), 2-hydroxyethyl acrylate (dP = 13.2), 2-hydroxy -3-acryloyloxypropyl methacrylate (dP = 6.7), 2-hydroxy-3-phenoxypropyl acrylate (dP = 6.9), (3-ethyl-3-oxetanylmethoxy) benzene (dP = 5.1) , (3-ethyl-3-hydroxymethyl) oxetane (dP = 7.9), (3 -Ethyl-3-oxetanylmethoxy) cyclohexane (dP = 4.1), bis {(3-ethyl-3-oxetanylmethoxymethyl) phenyl} methane (dP = 5.4), bis (3-ethyl-3-oxetanyl) Methyl) ether (dP = 6.0), vinylcyclohexene dioxide (dP = 7.3), bicyclohexene dioxide (dP = 5.9), epoxycyclohexylmethylepoxycyclohexanecarboxylate (dP = 7.3), etc. Is mentioned. Among these, considering moldability, curability and the like, phenoxyethyl acrylate (dP = 5.4), phenoxydiethylene glycol acrylate (dP = 5.5), 2-hydroxy-3-phenoxypropyl acrylate (dP = 6. It is preferable to use 9). These polymerizable monomers can be used alone or in a plurality of types.

Polymerizable monomer satisfying the requirement of (2) According to the study by the present inventors, the polymerizability having a molecular size of 0.70 nm or more in the penetration test into the PDMS mold described in detail in the examples. It was found that the monomer is less likely to penetrate PDMS. In PDMS, since the siloxane chain has a helical structure and the pore diameter is about 0.70 nm, it is considered that polymerizable monomers larger than this do not easily penetrate into the pores. That is, the polymerizable monomer having a branched structure and a large and rigid structure is large in size and difficult to penetrate into PDMS, while the polymerizable monomer having a linear structure is likely to penetrate into PDMS. it is conceivable that. The upper limit value of the molecular size is not particularly limited, but is 5.0 nm or less in consideration of easiness of imprinting, curability and the like.

  Specific examples of the polymerizable monomer that satisfies the requirement (2) include 2- (ο-phenylphenoxy) ethyl acrylate (molecular size: 0.92 nm), 9,9-bis [4- (2- Acryloyloxyethoxy) phenyl] fluorene (molecular size 1.08 nm), trimethylolpropane triacrylate (molecular size 0.81 nm), dipentaerythritol hexaacrylate (molecular size 1.20 nm), and the like. Among these, in consideration of moldability, curability and the like, it is preferable to use 2- (ο-phenylphenoxy) ethyl acrylate (molecular size: 0.92 nm) or trimethylolpropane triacrylate (molecular size: 0.81 nm). . These polymerizable monomers can be used alone or in a plurality of types.

(1) Polymerizable monomer satisfying both requirements of (2) As described above, the polymerizable monomer satisfying both requirements is specifically ethoxylated bisphenol A diacrylate (dP = 5.7, molecular size 1.03 nm), 1,3-bis (3-ethyl-3-oxetanylmethoxy) benzene (dP = 6.3, molecular size 0.75 nm), 1,4-bis (3-ethyl) -3-Oxetanylmethoxymethyl) benzene (dP = 5.9, molecular size 0.82 nm), 2,2′-bis (3-ethyl-3-oxetanylmethoxy) biphenyl (dP = 5.8, molecular size 0. 94 nm), bis (epoxymethylcyclohexylmethyl adipate (dP = 6.9, molecular size 0.85 nm), and the like.

A combination of suitable polymerizable monomers The polymerizable monomer can be used alone to constitute a polymerizable component, but in order to obtain a cured product having excellent curability, the above (1), It is preferable to use a combination of polymerizable monomers that satisfy at least one of the requirements (2) and (2). For example, when the polymerizable component is 100% by mass, 0 to 30% by mass of the polymerizable monomer that satisfies only the requirement (1), and 0% of the polymerizable monomer that satisfies only the requirement (2). It is preferable to make 40-100 mass% the polymerizable monomer which satisfies both the requirements of -40 mass% and (1) and (2).

In the curable composition for imprints of the present invention, the polymerizable component is essential, and other additives such as a polymerization initiator can be blended. As the polymerization initiator, it is preferable to use a photopolymerization initiator. Next, the photopolymerization initiator will be described.
(Photopolymerization initiator)
In the present invention, the photopolymerizable initiator is not particularly limited, and a radical polymerization initiator, a cationic polymerization initiator, or the like can be used.

  In the present invention, the radical photopolymerization initiator used for the polymerizable monomer having a radical polymerizable group is not particularly limited, and is capable of photopolymerizing a polymerizable monomer having a radical polymerizable group. Any photopolymerization initiator can be used if present.

(Photo radical polymerization initiator)
Specific examples of the radical photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-phenylpropane-1. -One, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy- 2-methylpropionyl) benzyl] phenyl} -2-methyl-propan-1-one, methyl benzoylformate, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl)- - (4-Moriforin-4-yl - butylphenyl) acetophenone derivative of butan-1-one and the like;
2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, methyl 2,4,6-trimethylbenzoylphenylphosphinate, 2-methylbenzoyldiphenyl Phosphine oxide, isopropyl pivaloylphenylphosphinate, bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis- (2, 6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis- (2,6-dimethoxybenzoyl) fe Ruphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis- (2 , 4,6-trimethylbenzoyl) phenylphosphine oxide, acylphosphine oxide derivatives such as bis- (2,5,6-trimethylbenzoyl) -2,4,4-trimethylpentylphosphine oxide;
1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3 -Yl]-, 1- (O-acetyloxime) and other O-acyloxime derivatives;
Such as diacetyl, acetylbenzoyl, benzyl, 2,3-pentadione, 2,3-octadione, 4,4′-dimethoxybenzyl, 4,4′-oxybenzyl, camphorquinone, 9,10-phenanthrenequinone, acenaphthenequinone, etc. α-diketone;
Benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin propyl ether; thioxanthone derivatives such as 2,4-diethoxythioxanthone, 2-chlorothioxanthone and 2-methylthioxanthone;
Benzophenone derivatives such as benzophenone, p, p'-dimethylaminobenzophenone, p, p'-methoxybenzophenone; bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- ( Titanocene derivatives such as 1H-pyrrol-1-yl) -phenyl) titanium are preferably used. These radical photopolymerization initiators may be used alone or in combination of two or more. In the present invention, it is preferable to use an acetophenone derivative, an acylphosphine oxide derivative, an O-acyloxime derivative, or an α-diketone.

  When α-diketone is used, it is preferably used in combination with a tertiary amine compound. Tertiary amine compounds that can be used in combination with α-diketone include N, N-dimethylaniline, N, N-diethylaniline, N, N-di-n-butylaniline, N, N-dibenzylaniline. N, N-dimethyl-p-toluidine, N, N-diethyl-p-toluidine, N, N-dimethyl-m-toluidine, p-bromo-N, N-dimethylaniline, m-chloro-N, N- Dimethylaniline, p-dimethylaminobenzaldehyde, p-dimethylaminoacetophenone, p-dimethylaminobenzoic acid, ethyl p-dimethylaminobenzoate, amyl p-dimethylaminobenzoate, methyl N, N-dimethylanthranylate, N, N -Di (hydroxyethyl) aniline, N, N-di (hydroxyethyl) -p-toluidine, p- (dimethylamino) phene Alcohol, p- (dimethylamino) stilbene, 5- (dimethylamino) -m-xylene, 4- (dimethylamino) pyridine, N, N-dimethyl-1-naphthylamine, N, N-dimethyl-2-naphthylamine, Tributylamine, tripropylamine, triethylamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, N-butyldiethanolamine, N, N-dimethylhexylamine, N, N-dimethyldodecylamine, N, N-dimethyl Examples include stearylamine, 2- (dimethylamino) ethyl methacrylate, 2-di (ethylamino) ethyl methacrylate and the like.

  In this invention, it is preferable that the usage-amount of the said radical photopolymerization initiator is 0.1-10 mass parts per 100 mass parts of polymerizable monomers which have the said radical polymerizable group, 0.1-5 More preferably, it is part by mass.

(Photocationic polymerization initiator)
In the present invention, the photoacid generator used for the photocationic polymerization initiator used for the polymerizable monomer having a cationically polymerizable group is not particularly limited, and is directly Bronsted acid by irradiation with ultraviolet rays or the like, or Any known compound can be used without any limitation as long as it is a compound capable of generating a Lewis acid. Examples of such a photoacid generator include diaryl iodonium salt compounds, sulfonium salt compounds, sulfonate ester compounds, and the like. Among these, diaryliodonium salt photoacid generators are excellent because of high polymerization activity.

  Specific examples of the photoacid generator include diphenyliodonium salt compounds such as diphenyliodonium, bis (p-chlorophenyl) iodonium, ditolyliodonium, bis (pt-butylphenyl) iodonium, p-isopropylphenyl. -P-methylphenyliodonium, bis (m-nitrophenyl) iodonium, pt-butylphenylphenyliodonium, p-methoxyphenylphenyliodonium, bis (p-methoxyphenyl) iodonium, p-octyloxyphenylphenyliodonium, p -Chloride such as phenoxyphenyl phenyl iodonium, bromide, p-toluenesulfonate, trifluoromethanesulfonate, tetrafluoroborate, tetrakis (pentafluorophenyl) Rate, tetrakispentafluorophenyl gallate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate and the like. Examples of the sulfonium salt compounds include dimethylphenacylsulfonium, dimethylbenzylsulfonium, dimethyl-4-hydroxyphenylsulfonium, dimethyl-4-hydroxynaphthylsulfonium, dimethyl-4,7-dihydroxynaphthylsulfonium, dimethyl-4,8-dihydroxynaphthylsulfonium. , Triphenylsulfonium, p-tolyldiphenylsulfonium, pt-butylphenyldiphenylsulfonium, diphenyl-4-phenylthiophenylsulfonium chloride, bromide, p-toluenesulfonate, trifluoromethanesulfonate, tetrafluoroborate, tetrakis Pentafluorophenyl borate, tetrakis pentafluorophenyl gallate, hexafluorophosphate, f Sa fluoro arsenate include hexafluoroantimonate. Examples of the sulfonate compound include benzoin tosylate, α-methylol benzoin tosylate, o-nitrobenzyl-p-toluenesulfonate, p-nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, and the like. You may use the said photo-acid generator 1 type or in mixture of 2 or more types. In this invention, it is preferable that the usage-amount of the said photocationic polymerization initiator is 0.1-10 mass parts per 100 mass parts of polymerizable monomers which have a cation polymeric group, 0.1-5 masses More preferably, it is a part.

(Other additive components)
Other known additives can be added to the photocurable composition for imprints of the present invention as long as the effects of the present invention are not impaired. Specifically, a sensitizer, a surfactant, a polymerization inhibitor and the like can be added.

(Sensitizer)
For the purpose of improving the sensitivity of the photopolymerization initiator, a sensitizer can be blended in the curable composition for imprints of the present invention. Examples of the sensitizer include those belonging to the compounds listed below and having an absorption wavelength in a wavelength region of 350 to 450 nm. For example, a sensitizer described in JP-A-2006-282875 can be used. Specific examples include polynuclear aromatic compounds, xanthenes, cyanines, merocyanines, thiazines, acridines, anthraquinones, coumarins and the like. Among these, polynuclear aromatic compounds such as 9-methylanthracene and 7,12-dimethylbenzo [a] anthracene, and coumarins such as 7-diethylamino-4-methylcoumarin can be preferably used. The above sensitizers may be used alone or in combination of two or more.

  In the present invention, the amount of the sensitizer used is preferably 0.1 to 10 parts by mass and more preferably 0.1 to 5 parts by mass per 100 parts by mass of the polymerizable monomer. .

(Surfactant)
Surfactant is mix | blended in order to improve the uniformity of a coating film. As the surfactant, a fluorine-containing surfactant, a silicone-containing surfactant, and an aliphatic surfactant can be used. In particular, in the case where the photocurable composition for imprinting is applied to a substrate such as a silicon wafer, an aliphatic surfactant should be used from the viewpoint that the composition can be uniformly applied without causing repelling. Is more preferable. For example, a surfactant described in JP 2014-57016 A can be used. Specific examples of surfactants include metal salts of higher alkyl sulfates, metal salts of aliphatic carboxylic acids, metal salts of higher alkyl ether sulfates, metal salts of sulfosuccinic acid diesters, phosphorus of higher alcohol ethylene oxide adducts. Acid ester salts, quaternary ammonium salts, alkyldimethylamine oxides, alkylcarboxybetaines, alkylsulfobetaines, amide amino acid salts, polyoxyalkylene alkyl ethers, polyoxyethylene distyrenated phenyl ethers, polyoxyethylene alkyl Examples include phenyl ethers, polyoxyethylene tribenzylphenyl ethers, fatty acid polyoxyethylene esters, polyoxyethylene sorbitan esters, and the like. Among these, it is preferable to use polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkyl phenyl ethers such as polyoxyalkylene alkyl ethers, polyoxyethylene lauryl phenyl ether, and the like. Surfactants can be used not only independently but also in combination of a plurality of types as required.

  When a surfactant is blended, it can be added at a ratio of 0.0001 to 1 part by mass, preferably 0.001 to 0.1 part by mass, per 100 parts by mass of the polymerizable monomer.

(Polymerization inhibitor)
The polymerization inhibitor is blended for stabilization so as not to polymerize during storage. Examples of the polymerization inhibitor include known ones. For example, the most typical ones include hydroquinone monomethyl ether, hydroquinone, dibutylhydroxytoluene and the like. When blending a polymerization inhibitor, it may be blended at a ratio of 0.01 to 1.0 part by weight, preferably 0.1 to 0.5 part by weight per 100 parts by weight of the polymerizable monomer. it can.

(Ingredients other than the above)
In addition, spherical fine particles such as hyperbranched polymers are added as other additive components because they can improve the releasability from the replica mold (pattern surface) and form a pattern with excellent reproducibility on the substrate. You can also. In this case, it is preferable to blend a spherical hyperbranched polymer having a diameter of 1 to 10 nm and a molecular weight of 10,000 to 100,000. It is preferable that a compounding quantity is 0.1-10 mass parts per 100 mass parts of said polymerizable monomers.

(Addition of organic solvent: coating agent)
The curable composition for imprints of the present invention can be mixed with an organic solvent and used as a coating agent in order to facilitate the formation of a coating film. In the present invention, a coating film made of the curable composition for imprints is formed on the substrate. However, since the curable composition for imprints of the present invention has a high viscosity, the coating property to the substrate and the coating film uniformity Considering the properties, it is preferable to dilute with an organic solvent to obtain a coating agent. However, the organic solvent is not an essential component, and it is not necessary to mix the organic solvent when the coating film can be formed only with the curable composition for imprints.

(Organic solvent)
When the organic solvent is mixed, the organic solvent to be used can be used without any limitation as long as it is an organic solvent in which the curable composition for imprints of the present invention is dissolved. For example, acetonitrile, tetrahydrofuran, toluene, chloroform, ethyl acetate, methyl ethyl ketone, N, N-dimethylformamide, N, N-dimethylacetamide, cyclohexanone, ethylene glycol, ethylene glycol monoisopropyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol Monomethyl ether acetate, methyl 3-methoxypropionate, ethylene glycol monoethyl ether acetate, ethyl lactate, ethyl 3-ethoxypropionate, butyl acetate, 2-heptanone, methyl isobutyl ketone, diacetone alcohol, t-butyl alcohol, polyethylene glycol And other alcohols.

  When an organic solvent is used, the amount used is not particularly limited, and is appropriately selected according to the thickness of the target coating film. Among these, when the total amount of the organic solvent and the curable composition for imprints is 100% by mass, the concentration of the solvent is preferably in the range of 10 to 99% by mass.

(Method for producing curable composition for imprint / coating agent)
The curable composition for imprints of the present invention can be produced by using the polymerizable component as an essential component and, if necessary, mixing a photopolymerization initiator and other components. What is necessary is just to mix an organic solvent further when setting it as a coating agent. The order of addition of these components is not particularly limited, but first, the polymerizable component and the organic solvent to be blended as necessary are sufficiently mixed to obtain a uniform state, and then the other components are mixed. Is preferred.

(Pattern formation method using curable composition for imprint / coating agent)
The pattern formation method using the curable composition for imprints of the present invention will be described. The pattern forming method of the present invention includes a coating film forming step, a curing step, and a pattern transfer step. These steps will be described.

(Coating film formation process)
The curable composition for imprints prepared by the above method, or a coating agent mixed with an organic solvent as necessary (a coating agent containing a curable composition for imprints) is applied onto a substrate. The substrate is not particularly limited, and examples thereof include a silicon substrate, a silicon carbide substrate, a group 13 element nitride single crystal substrate, and a sapphire substrate.

  First, a coating film is formed by apply | coating the coating agent containing the curable composition for imprints (it may be only the curable composition for imprints) on a board | substrate according to a well-known method. In addition, in order to improve the adhesiveness with the cured film which consists of a curable composition for imprints of this invention, a board | substrate can also be surface-treated.

  A coating film is formed on a substrate by applying the curable composition for imprints of the present invention by a known method such as a spin coating method, a dipping method, a dispensing method, an ink jet method, or a spray coating method. be able to. The thickness of the coating film is not particularly limited, and an optimum film thickness corresponding to the mold pattern to be used may be appropriately determined.

  In imprinting, an inverted pattern of a mold on which a pattern is formed is obtained. As a pattern of a cured film formed by polymerizing and curing a curable composition for imprints, a truncated cone shape and a cylindrical shape are generally used. Therefore, imprinting is performed using a mold having a frustoconical or cylindrical inverted pattern. That is, the mold pattern is a concave frustoconical or cylindrical pattern. Such molds are commercially available in various patterns.

  Moreover, you may add a prebaking process as needed after coating-film formation. The pre-baking temperature is not particularly limited as long as it is a temperature at which the coating film is dried, but can be usually selected from a range of 40 ° C to 150 ° C. Since the composition of the polymerizable monomer may change due to volatilization, the drying temperature is preferably 100 ° C. or lower.

(Curing process)
Next, the pattern forming surface of the mold on which a desired pattern is formed is brought into contact with the coating film. When the PDMS mold is pressed, the curable composition for imprints of the present invention does not require pressure, and can be filled into the mold recess while simply venting air by the weight of the PDMS mold. When pressure is applied, a low pressure of 0.01 to 1 MPa is preferable. Since the PDMS mold is a highly flexible silicone resin, if too much pressure is applied, the PDMS mold itself may be deformed and the transfer pattern may be distorted.

  Then, light is irradiated and the coating film is cured while the pattern surface of the PDMS mold and the coating film are in contact with each other. The light to be irradiated has a wavelength of 500 nm or less, and the light irradiation time is selected from the range of 0.1 to 300 seconds. Although it depends on the thickness of the coating film, etc., it is usually 1 to 60 seconds.

  When carrying out the atmosphere at the time of photopolymerization under air | atmosphere, it is preferable to use the curable composition for imprints of the cationic polymerization reaction system which is not influenced by the superposition | polymerization inhibition by oxygen. In the case of photocuring by radical polymerization reaction, photopolymerization in an atmosphere with little polymerization inhibition by oxygen is preferable. For example, a nitrogen gas atmosphere, an inert gas atmosphere, a fluorine gas atmosphere, a vacuum atmosphere, or the like is preferable.

(Pattern transfer process)
After light irradiation (photopolymerization), the PDMS mold is separated (released) from the cured coating film, thereby forming a pattern corresponding to the pattern formed on the pattern forming surface of the PDMS mold on the substrate. Can do. A resist laminate is formed by forming a pattern of a cured film on a substrate.

(Board processing method)
The cured film obtained from the photocurable composition for imprints of the present invention can be used as a mask when the surface of a sapphire substrate is processed. Chlorine gas is mainly used for etching the sapphire substrate, and a known gas used for reactive ion etching can be used. Specific examples include chlorine, boron trichloride, and carbon tetrachloride. If necessary, oxygen gas, fluorine-based gas, argon gas, and the like can be mixed and used. The LED PSS processing method, specifically, a method of processing a sapphire substrate that forms a conical uneven pattern from a resist laminated sapphire substrate by dry etching will be described.

  First, the thin part (residual film) of the cured film of the resist laminate is removed by dry etching, and after exposing the surface of the sapphire substrate, further dry etching is performed to remove all the cured film, thereby forming a conical uneven pattern. A sapphire substrate having the above is manufactured. Further, when the remaining film is as thin as 0.2 μm or less, it is possible to perform the removal of the remaining film and dry etching at a time without performing the process of removing the remaining film.

  As specific conditions for dry etching, an antenna power of 100 to 800 W can be selected. However, considering the prevention of alteration such as carbonization of the cured film and increasing the etching rate of the sapphire substrate, 200 to 500 W is desirable.

  Also, any power of 100 to 500 W can be selected as the bias power. Similarly, 200 to 300 W is desirable in consideration of preventing alteration such as carbonization of the cured film and increasing the etching rate of the sapphire substrate.

  As the flow rate of the etching gas, the total gas flow rate is usually set to 50 to 150 sccm. The ratio of a chlorine-based gas that actually performs etching and a gas such as argon for dilution can be arbitrarily set.

  The dry etching time needs to be performed until the cured film can be completely removed by dry etching. Usually, an etching time that is 20 to 30% longer than the time during which the cured film is completely removed (just etch time) is set. The actual etching time varies depending on the height of the cone formed by the cured film, but is usually 10 to 40 minutes.

  By the above method, a conical uneven pattern can be formed on the substrate.

Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited to these examples.
(Preparation of curable composition for imprint)
A composition composed of a polymerizable monomer, a photopolymerization initiator, and other additives was prepared at the ratio shown in Table 1.
(Coating formation of curable composition for imprint: coating forming process)
On a 2-inch sapphire substrate (single-sided mirror finish, thickness 430 μm, surface orientation c-plane), spin coating was performed at 4500 rpm for 20 seconds to apply the imprinting composition. In addition, the solvent was added to the curable composition for imprints, and the amount of solvent was adjusted so that the coating film thickness might be settled in 0.9-1.0 micrometer.

(Curing process-pattern transfer process: manufacture of photoimprint resist laminate)
PDMS mold having a frustoconical hole pattern (manufactured by Soken Chemical Co., Ltd., Freffimo PDMS HOP80-1700 / 1700, concave frustoconical pattern, upper diameter D1 = 1.5 μm, lower diameter D2 = 2.1 μm, high H = 1.7 μm, angle between side and bottom surface θ = 80 °, and a nanoimprint apparatus (SC-IVAX, X-300H) were used. The PDMS mold is brought into contact with the sapphire substrate having the coating film of the photocurable composition for imprints obtained as described above in a nitrogen atmosphere under no load, and UV irradiation (wavelength 365 nm, 20 mW / cm 2). ) Was carried out for 4 minutes, and the coating film was cured and a pattern made of a cured film corresponding to the pattern of the PDMS mold was transferred (the PDMS mold was released. Production of a resist laminate).

(Evaluation of penetration of curable composition for imprint into PDMS mold)
The amount of penetration of the curable composition for imprinting was evaluated from the weight difference between the PDMS molds before and after imprinting.

(Used compounds and their abbreviations)
(Polymerizable component: polymerizable monomer)
Polymerizable monomer AMP-10G satisfying only the requirement (1); Phenoxyethyl (meth) acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
A-200; Tetraethylene glycol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
APG-200; tripropylene glycol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
HEA; 2-hydroxyethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.).
OXT-101; 3-ethyl-3-hydroxymethyloxetane (manufactured by Toagosei Co., Ltd.).

Polymerizable monomer A-LEN-10 satisfying only the requirement (2); 2- (ο-phenylphenoxy) ethyl acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
A-TMPT; trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).

Polymerizable monomer ABE-300 satisfying both requirements of (1) and (2); ethoxylated bisphenol A diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
OXT-121; xylylene bisoxetane (manufactured by Toagosei Co., Ltd.).
OXT-221; 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (manufactured by Toagosei Co., Ltd.).

Polymerizable monomer IB-XA not satisfying both requirements of (1) and (2); Isoboronyl acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
A-NOD-N; 1,9-nonanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
A-DCP; tricyclodecane dimethanol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
OXT-212; 2-ethylhexyloxetane (manufactured by Toagosei Co., Ltd.).

(Polymerization initiator)
OXE02; ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime) (manufactured by Ciba Japan Co., Ltd.).
IDPI; 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate (manufactured by Tokyo Chemical Industry Co., Ltd.).

(Polymerization inhibitor)
HQME; hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.).
BHT; dibutylhydroxytoluene (manufactured by Wako Pure Chemical Industries, Ltd.).

(Sensitizer)
9MA; 9-methylanthracene (manufactured by Tokyo Chemical Industry Co., Ltd.).

(Organic solvent)
DAA: diacetone alcohol (manufactured by Wako Pure Chemical Industries, Ltd.).

Example 1
As shown in Table 1, 10.0 g of AMP-10G as a polymerizable monomer, 0.1 g of OXE02 as a photopolymerization initiator, and 0.015 g of HQME and 0.002 g of BHT as a polymerization inhibitor are uniformly mixed. Thus, a curable composition for imprint [1] was obtained. DAA 7.0g was added to this, and it filtered with the syringe filter with the hole diameter of 0.2 micrometer, Then, the coating film was formed in the sapphire substrate by spin coating. Then, the optical imprint was implemented using the PDMS mold which measured the weight beforehand, and the resist lamination sapphire substrate was obtained. After photoimprinting, the weight of the PDMS mold was measured, and the amount of penetration of the curable composition for imprinting was evaluated from the weight difference before and after photoimprinting. The evaluation results are shown in Table 1.

Examples 2-10, Comparative Examples 1-4
In the same manner as the procedure shown in Example 1 at the ratio shown in Table 1, the penetration evaluation of the curable composition for imprint into the PDMS mold was performed. In addition, the addition amount of DAA was adjusted so that the coating film after spin coating might be settled in 0.9-1.0 micrometer. The evaluation results are shown in Table 1.

  From Table 1, polymerizable monomers satisfying only the requirement (1) (Examples 1 to 5), polymerizable monomers satisfying only the requirement (2) (Examples 6 to 7), (1 ) And a polymerizable monomer that satisfies both requirements (Examples 8 to 10) (Examples 8 to 10) and does not satisfy both the requirements (1) and (2) (Comparative Examples 1 and 2) Compared with 4), the knowledge that the penetration into the PDMS mold was small was obtained.

  Based on this knowledge, a curable composition for imprints having a blending ratio shown in Table 2 was produced.

Example 11
As shown in Table 2, 4.7 g of AMP-10G, 4.8 g of A-LEN-10, 0.5 g of A-TMPT as a polymerizable monomer, 0.1 g of OXE02 as a photopolymerization initiator, inhibition of polymerization As an agent, 0.015 g of HQME and 0.002 g of BHT were uniformly mixed to obtain a curable composition for imprint [15]. DAA 12.0g was added to this, and it filtered with the syringe filter with the hole diameter of 0.2 micrometer, Then, the coating film was formed in the sapphire substrate by spin coating. Then, the optical imprint was implemented using the PDMS mold which measured the weight beforehand, and the resist lamination sapphire substrate was obtained. After photoimprinting, the weight of the PDMS mold was measured, and the amount of penetration of the curable composition for imprinting was evaluated from the weight difference before and after photoimprinting. The evaluation results are shown in Table 2.

Examples 12-17, Comparative Examples 5-11
In the same manner as the procedure shown in Example 1 at the ratio shown in Table 2, the penetration evaluation of the curable composition for imprint into the PDMS mold was performed. In addition, the addition amount of DAA was adjusted so that the coating film after spin coating might be settled in 0.9-1.0 micrometer. The evaluation results are shown in Table 1.

  From Table 2, a polymerizable monomer that satisfies only the requirement (1), a polymerizable monomer that satisfies only the requirement (2), and a polymerization property that satisfies both the requirements (1) and (2) The curable compositions for imprints (Examples 11 to 17) composed of only three polymerizable monomers are small in penetration into the PDMS mold. On the other hand, the curable composition for imprints (Comparative Examples 5 to 11) containing a polymerizable monomer that does not satisfy the requirements of both (1) and (2) is used when the proportion of the polymerizable monomer is low. Also gained knowledge that the penetration into the PDMS mold would increase.

31 Substrate 32 Curable composition for imprint 33 PDMS mold

Claims (3)

A curable composition for imprints used when imprinting is performed using a mold made of polydimethylsiloxane, which is a polymerizable monomer that satisfies at least one of the following requirements (1) and (2) A curable composition for imprints, comprising a polymerizable component.
(1) The polarization term (dP) of the Hansen solubility parameter (HSP) is 4.0 or more.
(2) The molecular size is 0.70 nm or more. A coating film forming step of applying a coating agent containing the curable composition for imprints according to claim 1 on a substrate and forming a coating film comprising the composition,
In the presence of oxygen, a pattern forming surface of a mold made of polydimethylsiloxane having a pattern formed thereon is brought into contact with the coating film, and in this state, the coating film is cured by irradiating light, and the mold is cured. A pattern is formed on the base substrate, comprising a pattern transfer step of forming a pattern corresponding to the pattern formed on the pattern forming surface of the mold on the substrate. A method for producing a resist laminate.   After the resist laminate is manufactured by the method according to claim 2, etching is performed by bringing the surface of the resist laminate formed with the etching gas into contact with the pattern formed on the resist laminate as a mask. A method for manufacturing a substrate on which a pattern is formed.

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