Patent Application
20230058755
The present application claims priority under 35 U.S.C §119 to Japanese Patent Application No. 2021-134049 filed on Aug. 19, 2021. Each of the above application(s) is hereby expressly incorporated by reference, in its entirety, into the present application.
The present invention relates to a curable composition for imprinting, a cured product, a method for producing an imprint pattern, and a method for producing a device.
An imprint method is a technique of transferring a fine pattern to a material by pressing a die (generally called a mold or a stamper) on which a pattern is formed. Since precise fine patterns can be easily made by the imprint method, in recent years, the imprint method is expected to be applied to various fields such as a precision processing field for semiconductor integrated circuits. In particular, a nanoimprint technique for forming fine patterns on the order of nanometers has attracted attention.
JP2013-65768A discloses a photo-imprint material that includes (A) a compound having a specific silicone skeleton and (B) a photopolymerization initiator, in which the content of the component (B) is 0.5 phr to 30 phr relative to the total mass of the component (A).
JP2016-524330A discloses an imprint material that can be used for imprint lithography and is curable, the imprint material being composed of a mixture containing at least one polymerizable main component and at least one sub-component.
As the imprint method, methods called a thermal imprint method and a curing imprint method have been proposed in view of the transfer method thereof. In the thermal imprint method, a mold is pressed against a thermoplastic resin heated to a glass transition temperature (hereinafter, also referred to as “Tg”) or higher, and the mold is released after cooling to form a fine pattern. In this method, various materials can be selected; however, this method also has a problem in that it is difficult to form a fine pattern because, for example, a high pressure is required during pressing, and the dimensional accuracy decreases due to thermal shrinkage or the like.
On the other hand, in the curing imprint method, for example, while a mold is pressed against a curable film formed from a curable composition for imprinting, the curable film is cured by light or heat, and the mold is then released. Since imprinting is performed on an uncured product, a part or all of high-pressure application and high-temperature heating can be omitted, and a fine pattern can be easily made. In addition, since the dimensional change before and after curing is small, the curing imprint method is advantageous in that a fine pattern can be formed with high accuracy.
Recently, new developments such as a nanocasting method that combines the advantages of both the thermal imprint method and the curing imprint method, and a reversal imprint method for making a three-dimensional laminated structure have also been reported.
In the curing imprint method, a curable composition for imprinting is applied onto a support (whose surface is subjected to an adhesion treatment as necessary) and dried as necessary to form a curable film, and a mold made of a light-transmitting material such as quartz is then pressed against the curable film. The curable composition for imprinting is cured by light irradiation, heating, or the like in a state in which the mold is pressed against the curable film, and the mold is then released to produce a cured product to which a target pattern has been transferred.
Examples of the method for applying the curable composition for imprinting onto the support include a spin coating method and an inkjet method.
A method of performing microfabrication using a transferred imprint pattern as a mask is referred to as nanoimprint lithography (NIL) and is being developed as a next-generation lithography technique that replaces the existing ArF immersion process. Therefore, the curable composition for imprinting used in NIL is required to be capable of resolving an ultrafine pattern of 20 nm or less and to have high etching resistance as a mask for microfabrication of an object to be processed, similarly to an extreme ultraviolet (EUV) resist. Specific examples of curable compositions for imprinting intended to be used as a mask include those described in JP5426814B, JP2015-009171A, JP2015-185798A, JP2015-070145A, and JP2015-128134A.
In the curing imprint method, for the purpose of, for example, suppressing deformation, breakage, and the like of a cured product, a force required to peel a mold and a cured product of a curable composition for imprinting from each other is required to be small.
In the present specification, when the force required to peel a cured product of a curable composition for imprinting and a mold from each other is small, the composition is considered to be excellent in terms of mold releasability of the resulting cured product.
An object of the present invention is to provide a curable composition for imprinting, the curable composition being excellent in mold releasability, a cured product of the curable composition for imprinting, a method for producing an imprint pattern using the curable composition for imprinting, and a method for producing a device, the method including the method for producing an imprint pattern.
Representative embodiments of the present invention will be described below.
According to the present invention, there are provided a curable composition for imprinting, the curable composition being excellent in mold releasability, a cured product of the curable composition for imprinting, a method for producing an imprint pattern using the curable composition for imprinting, and a method for producing a device, the method including the method for producing an imprint pattern.
Hereafter, typical embodiments of the present invention will be described. Each component will be described on the basis of the typical embodiments for convenience, but the present invention is not limited to such embodiments.
In the present specification, a range of numerical values expressed with “to” means a range that includes a numerical value before “to” as a lower limit and a numerical value after “to” as an upper limit.
In the present specification, the term “step” refers to not only an independent step but also a step that is not clearly distinguished from another step as long as a desired effect of the step can be achieved.
In the present specification, with regard to groups (atomic groups), an expression without the term of substituted or unsubstituted encompasses groups (atomic groups) having no substituents and also groups (atomic groups) having substituents. For example, a simple expression of “alkyl group” encompasses both an alkyl group having no substituents (unsubstituted alkyl group) and alkyl groups having substituents (substituted alkyl groups).
In the present specification, the term “exposure” refers to not only drawing using light but also drawing using a particle beam such as an electron beam or an ion beam unless otherwise specified. Examples of the energy ray used for drawing include actinic rays such as a bright-line spectrum of a mercury lamp, far ultraviolet rays typified by an excimer laser, extreme ultraviolet rays (EUV light), and X-rays, and particle beams such as an electron beam and an ion beam.
In the present specification, the term “(meth)acrylate” means both or one of “acrylate” and “methacrylate”, the term “(meth)acryl” means both or one of “acryl” and “methacryl”, and the term “(meth)acryloyl” means both or one of “acryloyl” and “methacryloyl”.
In the present specification, solid components in a composition mean components other than a solvent, and the content (concentration) of the solid components in the composition is represented by the mass percentage of the components other than the solvent relative to the total mass of the composition unless otherwise specified.
In the present specification, unless otherwise specified, the temperature is 23° C., the atmospheric pressure is 101,325 Pa (1 atm), and the relative humidity is 50 %RH.
In the present specification, the weight-average molecular weight (Mw) and the number-average molecular weight (Mn) are represented as values in terms of polystyrene according to gel permeation chromatography (GPC measurement) unless otherwise specified. The weight-average molecular weight (Mw) and the number-average molecular weight (Mn) can be determined with, for example, HLC-8220 (manufactured by Tosoh Corporation) using, as columns, a guard column HZ-L, TSKgel Super HZM-M, TSKgel Super HZ4000, TSKgel Super HZ3000, and TSKgel Super HZ2000 (manufactured by Tosoh Corporation).
Unless otherwise specified, THF (tetrahydrofuran) is used as an eluant for the measurement. Unless otherwise specified, a detector at a wavelength of 254 nm of UV rays (ultraviolet rays) is used for the detection in the GPC measurement.
In the present specification, when “on” or “under” is used for the description with respect to the positional relationship between layers constituting a laminate, it is sufficient that another layer is disposed on the upper side or the lower side of a reference layer among a plurality of layers to which attention is paid. That is, a third layer or element may be further disposed between the reference layer and the other layer, and the reference layer and the other layer need not be in contact with each other. Unless otherwise specified, a direction in which layers are stacked with respect to a support is referred to as “upward”, or when a photosensitive layer is provided, a direction from a support toward the photosensitive layer is referred to as “upward”, and the opposite direction is referred to as “downward”. Note that such a definition of upward and downward directions is for convenience in the present specification, and in actual embodiments, the “upper” direction in the present specification may be different from the vertically upward direction.
In the present specification, the term “imprinting” preferably refers to a transfer of a pattern with a size of 1 nm to 10 mm and more preferably refers to a transfer of a pattern with a size of about 10 nm to 100 µm (nanoimprinting).
A curable composition for imprinting according to the present invention includes a compound A which is a polymerizable compound having two or more radical polymerizable groups, a compound B which is a radical polymerization initiator, and a compound C which is at least one selected from the group consisting of an organopolysiloxane having only one radical polymerizable group and having no poly(oxyalkylene) group, an organopolysiloxane having only one radical polymerizable group and having a poly(oxyalkylene) group, and an organopolysiloxane having no radical polymerizable group and having a poly(oxyalkylene) group.
Hereinafter, of the compound C, an “organopolysiloxane having only one radical polymerizable group and having no poly(oxyalkylene) group” is also referred to as a “compound C-1”, an “organopolysiloxane having only one radical polymerizable group and having a poly(oxyalkylene) group” is also referred to as a “compound C-2”, and an “organopolysiloxane having no radical polymerizable group and having a poly(oxyalkylene) group” is also referred to as a “compound C-3”.
A cured product obtained from the curable composition for imprinting according to the present invention is excellent in mold releasability.
The mechanism of this effect is not known but is presumed as follows.
The curable composition for imprinting according to the present invention includes a compound C which is at least one selected from the group consisting of an organopolysiloxane having only one radical polymerizable group and having no poly(oxyalkylene) group, an organopolysiloxane having only one radical polymerizable group and having a poly(oxyalkylene) group, and an organopolysiloxane having no radical polymerizable group and having a poly(oxyalkylene) group.
When an organopolysiloxane having only one radical polymerizable group (the compound C-1 or C-2 described above) is included as the compound C, an organopolysiloxane structure derived from an organopolysiloxane structure having only one radical polymerizable group is introduced into a polymer formed from the compound A and having a high crosslinking density.
As a result, the modulus of elasticity near the surface of an imprint pattern (also referred to as a surface elastic modulus) can be reduced, and releasability from the mold can be improved.
When an organopolysiloxane having a poly(oxyalkylene) group (the compound C-2 or C-3 described above) is included as the compound C, the compound C is unevenly distributed on the surface of an imprint pattern because the poly(oxyalkylene)group is likely to adsorb to the mold.
As a result, since the organopolysiloxane structure derived from the compound C, which is a structure having a low surface free energy, is also introduced near the surface of the imprint pattern, the force required to release the imprint pattern from the mold can be reduced, and the releasability from the mold can be improved.
In addition, when the compound A is an organopolysiloxane, both the compounds A and C have an organopolysiloxane structure, and thus, probably, a coating film is less likely to have an inhomogeneous structure, such as a sea-island structure, and also have excellent stability.
Hereinafter, the curable composition for imprinting according to the present invention will be described in detail.
The curable composition for imprinting according to the present invention includes a compound A which is a polymerizable compound having two or more radical polymerizable groups.
In the curable composition for imprinting according to the present invention, the component having the highest content among the components other than a solvent included in the curable composition for imprinting is preferably the compound A.
The radical polymerizable groups in the compound A are each preferably an ethylenically unsaturated bond-containing group, and examples thereof include a (meth)acryloyl group, a (meth)acryloxy group, a (meth)acrylamide group, a vinyl group, a vinyloxy group, an allyl group, a maleimide group, and a group in which a vinyl group is directly bonded to an aromatic ring (for example, a vinylphenyl group). A (meth)acrylamide group or a (meth)acryloxy group is more preferred, an acrylamide group or an acryloxy group is still more preferred, and an acryloxy group is particularly preferred.
A radical polymerizable group value of the compound A is preferably 100 to 15,000, more preferably 200 to 10,000, and still more preferably 300 to 5,000.
In the present specification, the radical polymerizable group value of a compound is calculated by the following formula.
(Radical polymerizable group value) = (Number-average molecular weight of compound)/(Number of polymerizable groups in compound)
When the radical polymerizable group value is equal to or more than the lower limit, it is considered that the modulus of elasticity at the time of curing is within an appropriate range to achieve good mold releasability. On the other hand, when the polymerizable group value is equal to or less than the upper limit, it is considered that the resulting cured product pattern has a crosslinking density within an appropriate range to achieve a good resolution of the transfer pattern.
From the viewpoint of stability of the coating film, the compound A is preferably an organopolysiloxane having two or more radical polymerizable groups.
The organopolysiloxane refers to a compound containing siloxane bonds (-Si-O-Si-O-Si-) as a skeleton and having an organic group bonded to a silicon atom thereof.
In the organic group, the atom bonded to the silicon atom is preferably a carbon atom.
An atom or group other than an organic group (for example, a hydrogen atom, a hydroxy group, or a hydrolyzable group) may be bonded to some of the silicon atoms.
The hydrolyzable group is a group that can react with water to form a hydroxy group, and examples thereof include a halogen atom (such as a chlorine atom), an alkoxy group, an acyl group, and an amino group.
The organic group is preferably a hydrocarbon group, and more preferably an aromatic hydrocarbon group or a saturated aliphatic hydrocarbon group. The hydrocarbon group, the aromatic hydrocarbon group, and the saturated aliphatic hydrocarbon group may each further have a substituent. Examples of the substituent include a halogen atom, an alkoxy group, an aryloxy group, and a group including the radical polymerizable group mentioned above.
The compound A is preferably a compound having at least one of a siloxane structure of the D unit represented by the following formula (S1) or a siloxane structure of the T unit represented by the following formula (S2).
In formula (S1) or formula (S2), RS1 to RS3 each independently represent a hydrogen atom or a monovalent substituent, and each* independently represents a bonding site to another structure.
RS1 to RS3 are each independently preferably a monovalent substituent.
The monovalent substituent is preferably an aromatic hydrocarbon group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms) or an aliphatic hydrocarbon group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and still more preferably 1 to 6 carbon atoms). Of these, a cyclic or chain-like (linear or branched) alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms) or a group including a polymerizable group is preferred.
Specific examples of the structure of the organopolysiloxane include partial structures represented by the following formulae (s-1) to (s-9). Q in the formulae is the group including a polymerizable group. A plurality of these structures may be present in the compound or may be present in combination.
The organopolysiloxane which is the compound A is preferably a reaction product of a silicone resin and a compound having a polymerizable group.
The silicone resin is preferably a reactive silicone resin.
Examples of the reactive silicone resin include modified silicone resins having the silicone skeleton described above, such as monoamine-modified silicone resins, diamine-modified silicone resins, special amino-modified silicone resins, epoxy-modified silicone resins, alicyclic-epoxy-modified silicone resins, carbinol-modified silicone resins, mercapto-modified silicone resins, carboxy-modified silicone resins, hydrogen-modified silicone resins, amino/polyether-modified silicone resins, epoxy/polyether-modified silicone resins, and epoxy/aralkyl-modified silicone resins.
The compound having a polymerizable group is preferably a compound having a polymerizable group and a group that can react with an alkoxysilyl group or a silanol group, and more preferably a compound having a polymerizable group and a hydroxy group.
When the modified silicone resin described above is used as the silicone resin, a compound having a polymerizable group and a group that reacts with an amino group, an epoxy group, a mercapto group, a carboxy group, or the like included in the modified silicone resin may be used as the compound having a polymerizable group.
Preferred embodiments of the polymerizable group in the compound having a polymerizable group are the same as the preferred embodiments of the polymerizable group in the polymerizable compound described above.
Of these, as the compound having a polymerizable group, a hydroxyalkyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.
More specifically, the organopolysiloxane is preferably a reaction product of a compound having a polymerizable group and a group (for example, a hydroxy group) that can react with an alkoxysilyl group or a silanol group and a silicone resin having an alkoxysilyl group or a silanol group.
The weight-average molecular weight of the organopolysiloxane which is the compound A is preferably 300 to 10,000, more preferably 400 to 7,000, and still more preferably 500 to 5,000.
The number of radical polymerizable groups in the organopolysiloxane which is the compound A is preferably two or more, more preferably three or more, and still more preferably four or more in one molecule. The upper limit is preferably 50 or less, more preferably 40 or less, still more preferably 30 or less, and even still more preferably 20 or less.
The organopolysiloxane which is the compound A preferably has a viscosity of 100 mPa·s or more, more preferably 120 mPa·s or more, and still more preferably 150 mPa·s or more, at 23° C. The upper limit of the viscosity is preferably 2,000 mPa·s or less, more preferably 1,500 mPa·s or less, and still more preferably 1,200 mPa·s or less.
In the present specification, unless otherwise specified, the viscosity is a value measured using an E-type rotational viscometer RE85L manufactured by Toki Sangyo Co., Ltd. and a standard cone rotor (1°34’ × R24) while the temperature of a sample cup is adjusted to 23° C. Other details regarding the measurement are based on JISZ8803:2011. Two samples are prepared for one level, and each sample is measured three times. The arithmetic mean value of the total of six measurements is adopted as the evaluation value.
The compound A may be another high-molecular-weight polymerizable compound different from the organopolysiloxane described above.
Examples of the other high-molecular-weight polymerizable compound include compounds including a ring structure (ring-containing compounds) and dendrimer-type compounds.
The weight-average molecular weight of the other high-molecular-weight polymerizable compound is 800 or more, preferably 1,000 or more, more preferably 1,500 or more, and still more preferably more than 2,000. The upper limit of the weight-average molecular weight is not particularly specified, but is preferably, for example, 100,000 or less, more preferably 50,000 or less, still more preferably 10,000 or less, even more preferably 8,000 or less, yet still more preferably 5,000 or less, yet even still more preferably 3,500 or less, and particularly more preferably 3,000 or less. When the molecular weight is equal to or more than the lower limit, the volatilization of the compound is suppressed, and characteristics of the composition and the coating film are stabilized. In addition, a good viscosity for maintaining the form of the coating film can also be ensured. Furthermore, the effect of suppressing the amount of mold release agent to be small can be complemented to realize good mold releasability of the film. When the molecular weight is equal to or less than the upper limit, a low viscosity (fluidity) necessary for pattern filling is likely to be ensured, which is preferable.
Examples of the ring structure in the compound including a ring structure (ring-containing compound) include an aromatic ring and an alicyclic ring. Examples of the aromatic ring include an aromatic hydrocarbon ring and an aromatic heterocycle.
The aromatic hydrocarbon ring preferably has 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms. Specific examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a phenalene ring, a fluorene ring, a benzocyclooctene ring, an acenaphthylene ring, a biphenylene ring, an indene ring, an indane ring, a triphenylene ring, a pyrene ring, a chrysene ring, a perylene ring, and a tetrahydronaphthalene ring. Of these, a benzene ring or a naphthalene ring is preferred, and a benzene ring is more preferred. The aromatic ring may have a structure in which a plurality of aromatic rings are linked together, and examples thereof include a biphenyl structure and a diphenylalkane structure (for example, 2,2-diphenylpropane). (The aromatic hydrocarbon ring specified here is referred to as aCy.)
The aromatic heterocycle preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 5 carbon atoms. Specific examples thereof include a thiophene ring, a furan ring, a dibenzofuran ring, a pyrrole ring, an imidazole ring, a benzimidazole ring, a pyrazole ring, a triazole ring, a tetrazole ring, a thiazole ring, a thiadiazole ring, an oxadiazole ring, an oxazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, an isoindole ring, an indole ring, an indazole ring, a purine ring, a quinolizine ring, an isoquinoline ring, a quinoline ring, a phthalazine ring, a naphthyridine ring, a quinoxaline ring, a quinazoline ring, a cinnoline ring, a carbazole ring, an acridine ring, a phenazine ring, a phenothiazine ring, a phenoxathiin ring, and a phenoxazine ring. (The aromatic heterocycle specified here is referred to as hCy.)
The alicyclic ring preferably has 3 to 22 carbon atoms, more preferably 4 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms. Specific examples of the aliphatic hydrocarbon ring include a cyclopropane ring, a cyclobutane ring, a cyclobutene ring, a cyclopentane ring, a cyclohexane ring, a cyclohexene ring, a cycloheptane ring, a cyclooctane ring, a dicyclopentadiene ring, a spirodecane ring, a spirononane ring, a tetrahydrodicyclopentadiene ring, an octahydronaphthalene ring, a decahydronaphthalene ring, a hexahydroindane ring, a bornane ring, a norbornane ring, a norbornene ring, isobornane ring, a tricyclodecane ring, a tetracyclododecane ring, and an adamantane ring. Examples of the aliphatic heterocycle include a pyrrolidine ring, an imidazolidine ring, a piperidine ring, a piperazine ring, a morpholine ring, an oxirane ring, an oxetane ring, an oxolane ring, an oxane ring, and a dioxane ring. (The alicyclic ring specified here is referred to as fCy.)
In the present invention, when the other high-molecular-weight polymerizable compound is a ring-containing compound, the ring-containing compound is preferably a compound including an aromatic hydrocarbon ring, and more preferably a compound having a benzene ring. The compound may be, for example, a compound having a structure represented by the following formula (C-1).
In the formula, Ar represents the aromatic hydrocarbon ring or aromatic heterocycle described above.
L1 and L2 are each independently a single bond or a linking group. Examples of the linking group include an oxygen atom (oxy group), a carbonyl group, an imino group, an alkylene group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably having 1 to 3 carbon atoms), and a group of a combination of the foregoing. Of these, a (poly)alkyleneoxy group is preferred. The (poly)alkyleneoxy group may be a group formed of a single alkyleneoxy group or a group in which a plurality of alkyleneoxy groups are repeatedly linked together. The order of the alkylene group and the oxy group is not limited. The number of repetitions of the alkyleneoxy group is preferably 1 to 24, more preferably 1 to 12, and still more preferably 1 to 6. An alkylene group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and still more preferably 1 to 6 carbon atoms) may be interposed in the (poly)alkyleneoxy group in relation to the linkage with the ring Ar serving as a mother nucleus or a polymerizable group Q. Accordingly, the linking group may be a (poly)alkyleneoxy=alkylene group.
R3 is any substituent, and examples thereof include an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms), an alkenyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably 2 or 3 carbon atoms), an aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms), an arylalkyl group (preferably having 7 to 23 carbon atoms, more preferably 7 to 19 carbon atoms, and still more preferably 7 to 11 carbon atoms), a hydroxy group, a carboxy group, an alkoxy group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and still more preferably 1 to 6 carbon atoms), an acyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably 2 or 3 carbon atoms, and an alkylcarbonyl group is preferred), and an aryloyl group (preferably having 7 to 23 carbon atoms, more preferably 7 to 19 carbon atoms, and still more preferably 7 to 11 carbon atoms).
L3 is a single bond or a linking group. Examples of the linking group include those of L1 and L2 described above.
n3 is preferably 3 or less, more preferably 2 or less, still more preferably 1 or less, and particularly preferably 0.
Q1 and Q2 are each independently a polymerizable group, and preferred examples thereof include those of the polymerizable group described above.
In the ring-containing compound, an increase in the number of side chains having a polymerizable group enables the formation of a strong crosslinked structure at the time of curing and tends to improve the resolution. From this viewpoint, nq is 1 or more, and preferably 2 or more. The upper limit is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less.
Similarly, from the viewpoint of easily forming a homogeneous crosslinked structure, when groups including a polymerizable group or substituents are introduced into the ring structure, the substituents are preferably arranged in series.
The other high-molecular-weight polymerizable compound may be a dendrimer-type compound. The dendrimer means a dendritic polymer having a structure that branches from the center in an ordered manner. The dendrimer is constituted by a central molecule (trunk) called a core and side chain moieties (branches) called dendrons. The dendrimer is generally a fan-shaped compound as a whole but may be a dendrimer in which dendrons extend in a semicircular or circular shape. A polymerizable compound can be obtained by introducing a group having a polymerizable group into a dendron moiety (for example, a terminal moiety away from the core) of the dendrimer. If a (meth)acryloyl group is used as the polymerizable group to be introduced, a dendrimer-type polyfunctional (meth)acrylate can be obtained.
For the dendrimer-type compound, for example, the matters disclosed in JP5512970B can be referred to, and the description of the publication is incorporated herein. Polymerizable Group Value
The polymerizable group value of the other high-molecular-weight polymerizable compound is preferably 130 or more, more preferably 150 or more, still more preferably 160 or more, even more preferably 190 or more, and yet still more preferably 240 or more. The upper limit of the polymerizable group value is preferably 2,500 or less, more preferably 1,800 or less, still more preferably 1,000 or less, even more preferably 500 or less, yet still more preferably 350 or less and may be 300 or less.
When the polymerizable group value of the other high-molecular-weight polymerizable compound is equal to or more than the lower limit, it is considered that the modulus of elasticity at the time of curing is within an appropriate range to achieve good mold releasability. On the other hand, when the polymerizable group value is equal to or less than the upper limit, it is considered that the resulting cured product pattern has a crosslinking density within an appropriate range to achieve a good resolution of the transfer pattern.
The number of polymerizable groups in the other high-molecular-weight polymerizable compound is two or more in one molecule in the case of a ring-containing compound. The upper limit is preferably four or less, and more preferably three or less.
In the case of a dendrimer-type compound, the number of polymerizable groups is preferably 5 or more, more preferably 10 or more, and still more preferably 20 or more in one molecule. The upper limit is preferably 1,000 or less, more preferably 500 or less, and still more preferably 200 or less.
The other high-molecular-weight polymerizable compound preferably has a viscosity of 100 mPa·s or more, more preferably 120 mPa·s or more, and still more preferably 150 mPa·s or more, at 23° C. The upper limit of the viscosity is preferably 2,000 mPa·s or less, more preferably 1,500 mPa·s or less, and still more preferably 1,200 mPa·s or less.
It is also preferable that the composition according to the present invention contain a low-molecular-weight polymerizable compound as the compound A.
The molecular weight of the low-molecular-weight polymerizable compound is preferably 1,000 or less, and more preferably 100 to 900.
The low-molecular-weight polymerizable compound is preferably a compound represented by the following formula (2). The use of such a compound tends to further enhance adhesiveness, mold release force, and temporal stability in a balanced manner.
In formula (2), R21 is a q-valent organic group, X1 is a radical polymerizable group, and q is an integer of 2 or more.
In formula (2), q is preferably an integer of 2 or more and 7 or less, more preferably an integer of 2 or more and 4 or less, still more preferably 2 or 3, and even more preferably 2.
In formula (2), preferred embodiments of the radical polymerizable group in X1 are the same as the preferred embodiments of the radical polymerizable group in the compound A described above.
In formula (2), R21 is preferably a divalent to heptavalent organic group, more preferably a divalent to tetravalent organic group, still more preferably a divalent or trivalent organic group, and even more preferably a divalent organic group. R21 is preferably a hydrocarbon group having at least one of a linear, branched, or ring structure. The number of carbon atoms of the hydrocarbon group is preferably 2 to 20, and more preferably 2 to 10.
When R21 is a divalent organic group, R21 is preferably an organic group represented by the following formula (1-2).
In the formula, Z1 and Z2 are each independently preferably a single bond, -O-, -Alk-, or -Alk-O-. Alk represents an alkylene group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms) and may have a substituent as long as the effect of the present invention is obtained.
R9 is preferably a single bond, a linking group selected from the group consisting of the following formulae (9-1) to (9-10), or a combination thereof. Of these, a linking group selected from the group consisting of formulae (9-1) to (9-3), (9-7), and (9-8) is preferred.
R101 to R117 are each any substituent. In particular, an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms), an aralkyl group (preferably having 7 to 21 carbon atoms, more preferably 7 to 15 carbon atoms, and still more preferably 7 to 11 carbon atoms), an aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms), a thienyl group, a furyl group, a (meth)acryloyl group, a (meth)acryloyloxy group, and a (meth)acryloyloxyalkyl group (where the alkyl group preferably has 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and still more preferably 1 to 6 carbon atoms) are preferred. R101 and R102, R103 and R104, R105 and R106, R107 and R108, R109 and R110, a plurality of R111, if present, a plurality of R112, if present, a plurality of R113, if present, a plurality of R114, if present, a plurality of R115, if present, a plurality of R116, if present, and a plurality of R117, if present may be bonded together to form a ring.
Ar is an arylene group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms), and specific examples thereof include a phenylene group, a naphthalenediyl group, an anthracenediyl group, a phenanthrenediyl group, and a fluorenediyl group.
hCy1 is a heterocyclic group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 2 to 5 carbon atoms), and more preferably a five-membered ring or a six-membered ring. Specific examples of the heterocycle constituting hCy1 include the above-described aromatic heterocycles hCy, a pyrrolidone ring, a tetrahydrofuran ring, a tetrahydropyran ring, and a morpholine ring. Of these, a thiophene ring, a furan ring, and a dibenzofuran ring are preferred.
n and m are each a natural number of 100 or less, preferably 1 to 12, more preferably 1 to 6, and still more preferably 1 to 3.
p is an integer greater than or equal to 0 and less than or equal to the maximum substitutable number for each ring. The upper limit is, independently in each case, preferably a half or less of the maximum substitutable number, more preferably 4 or less, and still more preferably 2 or less.
The low-molecular-weight polymerizable compound is preferably represented by the following formula (2-1).
In formula (2-1), R9, Z1, and Z2 represent the same as R9, Z1, and Z2, respectively, in formula (1-2), and preferred ranges thereof are also the same.
These low-molecular-weight polymerizable compounds may be included alone or in combination of two or more thereof.
The type of atoms constituting the low-molecular-weight polymerizable compound used in the present invention is not particularly specified; however, the low-molecular-weight polymerizable compound is preferably constituted only by atoms selected from the group consisting of a carbon atom, an oxygen atom, a hydrogen atom, and a halogen atom, and more preferably constituted only by atoms selected from the group consisting of a carbon atom, an oxygen atom, and a hydrogen atom.
The low-molecular-weight polymerizable compound preferably has a polymerizable group value of 150 or more, more preferably 160 or more, still more preferably 190 or more, and even more preferably 240 or more, the polymerizable group value being defined above. The upper limit is preferably 2,500 or less, more preferably 1,800 or less, and still more preferably 1,000 or less.
The low-molecular-weight polymerizable compound preferably has a ring structure. Examples of the ring structure include examples of the aromatic hydrocarbon ring aCy, the aromatic heterocycle hCy, and the alicyclic ring fCy.
Examples of the compound A further include compounds having two or more radical polymerizable groups among compounds used in Examples described below, compounds described in paragraphs 0017 to 0024 and Examples of JP2014-090133A, compounds described in paragraphs 0024 to 0089 of JP2015-009171A, compounds described in paragraphs 0023 to 0037 of JP2015-070145A, and compounds described in paragraphs 0012 to 0039 of WO2016/152597A, but the present invention should not be construed as being limited thereto.
The curable composition for imprinting according to the present invention may further include, among the compounds described in the above publications, a compound that has only one radical polymerizable group but that does not correspond to the compound C.
The content of the compound is preferably 10% to 70% by mass, more preferably 20% to 60% by mass, and still more preferably 30% to 50% by mass relative to the total mass of the compound A.
The content of the compound A is preferably 30% by mass or more, more preferably 45% by mass or more, still more preferably 50% by mass or more, even more preferably 55% by mass or more and may be 60% by mass or more, or even 70% by mass or more, relative to the total solid content of the curable composition for imprinting. The upper limit is preferably less than 99% by mass, more preferably 98% by mass or less and may be 97% by mass or less.
Preferably, the boiling point of the compound A is determined in relation to a polymerizable compound included in a composition for forming an adhesive layer described later, and blending design is performed. The boiling point of the polymerizable compound is preferably 500° C. or lower, more preferably 450° C. or lower, and still more preferably 400° C. or lower. The lower limit is preferably 200° C. or higher, more preferably 220° C. or higher, and still more preferably 240° C. or higher.
The curable composition for imprinting includes a compound B which is a radical polymerization initiator.
The radical polymerization initiator is preferably a thermal radical polymerization initiator or a photo-radical polymerization initiator, and is preferably a photo-radical polymerization initiator from the viewpoint that the radical polymerization initiator can be used in the photo-imprint method.
Any compound may be used as the photo-radical polymerization initiator as long as the compound generates an active species for polymerizing the above-described polymerizable compound by light irradiation. In the present invention, a plurality of photo-radical polymerization initiators may be used in combination.
The content of the radical polymerization initiator used in the present invention is, for example, 0.01% to 15% by mass, preferably 0.1% to 12% by mass, and more preferably 0.2% to 7% by mass relative to the total solid content of the curable composition for imprinting. When two or more radical polymerization initiators are used, the total amount thereof is preferably within the range described above.
A content of the radical polymerization initiator of 0.01% by mass or more is preferable because sensitivity (rapid curability), resolution, line edge roughness, and coating film hardness tend to improve. On the other hand, a content of the radical polymerization initiator of 15% by mass or less is preferable because, for example, light-transmitting properties, colorability, and handleability tend to improve.
For the thermal radical polymerization initiator, components described in JP2013-036027A, JP2014-090133A, and JP2013-189537A can be used. With regard to, for example, the content, reference can be made to the description of the above publications.
The photo-radical polymerization initiator used in the present invention may be, for example, a commercially available initiator. For example, those described in paragraph 0091 of JP2008-105414A can be preferably used as such examples. Of these, acetophenone compounds, phenylglyoxylate compounds, acylphosphine oxide compounds, and oxime ester compounds are preferred in view of curing sensitivity and absorption characteristics.
Preferred examples of the acetophenone compounds include hydroxyacetophenone compounds, dialkoxyacetophenone compounds, and aminoacetophenone compounds. Preferred examples of the hydroxyacetophenone compounds include Irgacure (registered trademark) 2959 (1 - [4-(2-hydroxyethoxy )phenyl]-2-hydroxy-2-methyl-1 -propan-1 -one), Irgacure (registered trademark) 184 (1-hydroxycyclohexyl phenyl ketone), Irgacure (registered trademark) 500 (1-hydroxycyclohexyl phenyl ketone, benzophenone), and Darocure (registered trademark) 1173 (2-hydroxy-2-methyl-1-phenyl-1-propan-1-one), which are available from BASF.
Preferred examples of the dialkoxyacetophenone compounds include Irgacure (registered trademark) 651 (2,2-dimethoxy-l,2-diphenylethan-l-one), which is available from BASF.
Preferred examples of the aminoacetophenone compounds include Irgacure (registered trademark) 369 (2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone-1), Irgacure (registered trademark) 379 (EG) (2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)butan-1-one), and Irgacure (registered trademark) 907 (2-methyl-1-[4-(methylthio) phenyl]-2-(4-morpholinyl)-1-propanone), which are available from BASF.
Preferred examples of the phenylglyoxylate compounds include Irgacure (registered trademark) 754 and Darocure (registered trademark) MBF, which are available from BASF.
Preferred examples of the acylphosphine oxide compounds (polymerization initiators having an acylphosphine oxide group in the molecules) include Irgacure (registered trademark) 819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide) and Irgacure (registered trademark) 1800 (bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphineoxide), which are available from BASF, and Lucirin TPO (2,4,6-trimethylbenzoyldiphenyl phosphine oxide) and Lucirin TPO-L (2,4,6-trimethylbenzoylphenylethoxy phosphine oxide), which are available from BASF.
Preferred examples of the oxime ester compounds include Irgacure (registered trademark) OXE01 (1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime) and Irgacure (registered trademark) OXE02 (ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime)), which are available from BASF.
In the present invention, the term “light” encompasses not only light having a wavelength in a region of ultraviolet, near-ultraviolet, far-ultraviolet, visible, infrared, or the like and electromagnetic waves, but also radiation. Examples of the radiation include microwaves, electron beams, EUV, and X-rays. Laser beams such as 248 nm excimer laser, 193 nm excimer laser, and 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 having a plurality of different wavelengths (compound light). The exposure may be multiple exposure, or the entire surface may be exposed after the pattern formation for the purpose of, for example, increasing film hardness and etching resistance.
The curable composition for imprinting includes a compound C which is at least one selected from the group consisting of an organopolysiloxane having only one radical polymerizable group and having no poly(oxyalkylene) group (compound C-1), an organopolysiloxane having only one radical polymerizable group and having a poly(oxyalkylene) group (compound C-2), and an organopolysiloxane having no radical polymerizable group and having a poly(oxyalkylene) group (compound C-3).
The radical polymerizable group in the compound C (that is, the only one radical polymerizable group included in the compound C-1 or the compound C-2) is preferably an ethylenically unsaturated bond-containing group, and examples thereof include a (meth)acryloyl group, a (meth)acryloxy group, a (meth)acrylamide group, a vinyl group, a vinyloxy group, an allyl group, a maleimide group, and a group in which a vinyl group is directly bonded to an aromatic ring (for example, a vinylphenyl group). A (meth)acrylamide group, a (meth)acryloxy group, or a vinylphenyl group is more preferred, an acrylamide group, an acryloxy group, or a vinylphenyl group is still more preferred, and an acrylamide group is particularly preferred.
The poly(oxyalkylene) group in the compound C (that is, the poly(oxyalkylene) group included in the compound C-2 or the compound C-3) is a group in which two or more oxyalkylene groups are directly bonded together, preferably a group in which 5 to 100 oxyalkylene groups are directly bonded together, and more preferably a group in which 8 to 50 oxyalkylene groups are directly bonded together.
The oxyalkylene groups included in the poly(oxyalkylene) group may have the same structure or different structures.
When the poly(oxyalkylene) group includes two or more types of oxyalkylene groups having different structures, for example, the poly(oxyalkylene) group may be a group in which the two or more types of oxyalkylene groups having different structures are randomly bonded together, or may include a block of oxyalkylene groups having a certain structure and a block of oxyalkylene groups having another structure, and the arrangement of the oxyalkylene groups is not particularly limited.
The number of carbon atoms of the alkylene group in the poly(oxyalkylene) group is preferably 2 to 10, more preferably 2 to 4, and still more preferably 2 or 3.
The poly(oxyalkylene) group preferably includes an oxyalkylene group represented by the following formula (OA-1) and is more preferably a group consisting of an oxyalkylene group represented by the following formula (OA-1).
In formula (OA-1), RO1 and RO2 each independently represent a hydrogen atom or a methyl group, but RO1 and RO2 do not simultaneously represent a methyl group.
The poly(oxyalkylene) group is preferably a poly(ethyleneoxy) group, a poly(ethyleneoxy-ran-propyleneoxy) group, or a poly(ethyleneoxy-block-propyleneoxy) group.
“Poly(A-ran-B)” indicates that A and B are randomly bonded together, and “poly(A-block-B)” indicates that a block formed from A and a block formed from B are bonded together.
In a case where the compound C includes a poly(oxyalkylene) group, the content thereof (that is, the content of the poly(oxyalkylene) group in the compound C-2 or the compound C-3) is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less relative to the total mass of the composition. The lower limit of the content is not particularly limited and may be, for example, 1% by mass or more.
The compound C preferably includes a repeating unit represented by the following formula (S-1).
In formula (S-1), each R independently represents a hydrocarbon group.
In formula (S-1), each R is independently preferably an aromatic hydrocarbon group or an alkyl group, more preferably a phenyl group or a methyl group, and still more preferably a methyl group.
The content of the repeating unit represented by formula (S-1) in the compound C-1 is preferably 50% to 95% by mass, more preferably 60% to 90% by mass, and still more preferably 70% to 85% by mass.
The content of the repeating unit represented by formula (S-1) in the compound C-2 is preferably 5% to 80% by mass, more preferably 8% to 70% by mass, and still more preferably 10% to 50% by mass.
The content of the repeating unit represented by formula (S-1) in the compound C-3 is preferably 5% to 80% by mass, more preferably 8% to 70% by mass, and still more preferably 10% to 50% by mass.
The compound C may include at least one structure selected from the group consisting of a structure represented by the following formula (S2) and a structure represented by the following Formula (S3).
An embodiment in which the compound C includes neither the structure represented by the following formula (S2) nor the structure represented by the following formula (S3) is also one of preferred embodiments of the present invention.
In formula (S2) or formula (S3), RS3 represents a hydrogen atom or a monovalent substituent, and each * independently represents a bonding site to another structure. RS3 is preferably a monovalent substituent.
The monovalent substituent is preferably an aromatic hydrocarbon group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms) or an aliphatic hydrocarbon group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and still more preferably 1 to 6 carbon atoms). Of these, a cyclic or chain-like (linear or branched) alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms) or a group including a polymerizable group is preferred.
The compound C-2 or the compound C-3 preferably includes a constitutional unit represented by the following formula (S-2).
The compound C-2 or the compound C-3 may include only one constitutional unit represented by the following formula (S-2) or may include two or more constitutional units represented by the following formula (S-2).
In formula (S-2), R represents a hydrocarbon group, and RS1 represents a group having a poly(oxyalkylene) group.
In formula (S-2), preferred embodiments of R are the same as the preferred embodiments of R in formula (S-1).
In formula (S-2), preferred embodiments of the poly(oxyalkylene) group in RS1 are the same as the preferred embodiments of the above poly(oxyalkylene) group in the compound C.
In formula (S-2), RS1 is preferably a group represented by the following formula (RS-1).
In formula (RS-1), LS1 represents a single bond or a divalent linking group, ROA represents a poly(oxyalkylene) group, RS2 represents a hydrogen atom or a monovalent organic group, and * represents a bonding site to the silicon atom in formula (S-2).
In formula (RS-1), LS1 is preferably a single bond, a hydrocarbon group, or a group represented by a bond between one or more hydrocarbon groups and at least one compound selected from the group consisting of -O-, -CO-, -S-, -SO2-, and -NHCO-, and more preferably a single bond, a hydrocarbon group, or a group represented by a bond between a hydrocarbon group and -O-.
The hydrocarbon group in LS1 is preferably a hydrocarbon group having 2 to 20 carbon atoms, more preferably a hydrocarbon group having 2 to 10 carbon atoms, and still more preferably a hydrocarbon group having 2 to 4 carbon atoms.
The hydrocarbon group in LS1 may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group, but is preferably an alkylene group, an aromatic hydrocarbon group, or a group represented by a combination thereof, and more preferably an alkylene group.
In formula (RS-1), preferred embodiments of the poly(oxyalkylene) group in ROA are the same as the preferred embodiments of the above poly(oxyalkylene) group in the compound C.
In the compound C-2, RS2 in formula (RS-1) is preferably a hydrogen atom, a hydrocarbon group, the above-described radical polymerizable group, or a group represented by a combination of a hydrocarbon group and the above-described radical polymerizable group.
In the compound C-3, RS2 is preferably a hydrogen atom or a hydrocarbon group.
The hydrocarbon group in RS2 is preferably a hydrocarbon group having 2 to 20 carbon atoms, more preferably a hydrocarbon group having 2 to 10 carbon atoms, and still more preferably a hydrocarbon group having 2 to 4 carbon atoms.
The hydrocarbon group in LS1 may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group, but is more preferably an alkyl group, an aromatic hydrocarbon group, or a group represented by a combination thereof.
Specific examples of the constitutional unit represented by formula (S-2) are shown below, but the present invention is not limited thereto. In the following structural formulae, the subscript of the brackets indicates the number of repetitions. In the present specification, unless otherwise stated, the notation (CxH2xO)n(CyH2yO)m indicates a block copolymer including n blocks of (CxH2xO) and m blocks of (CyH2yO).
The content of the constitutional unit represented by formula (S-2) in the compound C-2 is preferably 5% to 80% by mass, more preferably 8% to 70% by mass, and still more preferably 10% to 50% by mass.
The content of the constitutional unit represented by formula (S-2) in the compound C-3 is preferably 5% to 80% by mass, more preferably 8% to 70% by mass, and still more preferably 10% to 50% by mass.
The compound C-2 or the compound C-3 preferably includes a structure represented by the following formula (S-3).
In formula (S-3), each R independently represents a hydrocarbon group, RS3 represents a group having a poly(oxyalkylene) group, and * represents a bonding site to another structure.
In formula (S-3), preferred embodiments of R are the same as the preferred embodiments of R in formula (S-1).
In formula (S-3), preferred embodiments of the poly(oxyalkylene) group in RS3 are the same as the preferred embodiments of the above poly(oxyalkylene) group in the compound C.
In formula (S-3), RS3 is preferably a group represented by the formula (RS-1) above.
In Formula (S-3), * is preferably a bonding site to the oxygen atom in the repeating unit represented by formula (S-1) or an oxygen atom in the constitutional unit represented by formula (S-2), and more preferably a bonding site to the oxygen atom in the repeating unit represented by formula (S-1).
Specific examples of the structure represented by formula (S-3) are shown below, but the present invention is not limited thereto. In the following structural formulae, * represents the same as * in formula (S-3), and the subscript of the brackets indicates the number of repetitions.
The content of the structure represented by formula (S-3) in the compound C-2 is preferably 5% to 80% by mass, more preferably 8% to 70% by mass, and still more preferably 10% to 50% by mass.
The content of the structure represented by formula (S-3) in the compound C-3 is preferably 5% to 80% by mass, more preferably 8% to 70% by mass, and still more preferably 10% to 50% by mass.
The compound C-1 or the compound C-2 may include only one constitutional unit represented by the following formula (S-4).
In formula (S-4), R represents a hydrocarbon group, and RS4 represents a group having a radical polymerizable group.
In formula (S-4), preferred embodiments of R are the same as the preferred embodiments of R in formula (S-1).
In formula (S-4), preferred embodiments of the radical polymerizable group in RS4 are the same as the preferred embodiments of the above radical polymerizable group in the compound C.
In formula (S-4), RS4 is preferably a group represented by the following formula (RS-4).
In formula (RS-4), LS2 represents a single bond or a divalent linking group, RS5 represents a radical polymerizable group, and * represents a bonding site to the silicone atom in formula (S-4).
In formula (RS-4), LS2 is preferably a linking group composed of an organic group, and more preferably a hydrocarbon group.
Examples of the hydrocarbon group in LS2 include an alkylene group (preferably having 1 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, and still more preferably 2 to 6 carbon atoms), an alkenylene group (preferably having 2 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, and still more preferably 2 to 6 carbon atoms), and an aromatic hydrocarbon group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms).
An embodiment in which LS2 in the compound C-2 includes the poly(oxyalkylene) group described above is also one of preferred embodiments of the present invention.
In the compound C-1, RS5 does not include the poly(oxyalkylene) group described above.
In formula (RS-4), preferred embodiments of the radical polymerizable group in RS5 are the same as the preferred embodiments of the above radical polymerizable group in the compound C.
A specific example of the constitutional unit represented by formula (S-4) is shown below, but the present invention is not limited thereto. In the following structural formula, the subscript of the brackets indicates the number of repetitions.
The compound C-1 or the compound C-2 may include only one structure represented by the following formula (S-5).
In formula (S-5), each R independently represents a hydrocarbon group, RS6 represents a group having a radical polymerizable group, and * represents a bonding site to another structure.
In formula (S-5), preferred embodiments of R are the same as the preferred embodiments of R in formula (S-1).
In formula (S-5), preferred embodiments of the radical polymerizable group in RS6 are the same as the preferred embodiments of the above radical polymerizable group in the compound C.
In formula (S-5), RS6 is preferably a group represented by the formula (RS-4) above.
In Formula (S-5), * is preferably a bonding site to the oxygen atom in the repeating unit represented by formula (S-1) or an oxygen atom in the constitutional unit represented by formula (S-2), and more preferably a bonding site to the oxygen atom in the repeating unit represented by formula (S-1).
Specific examples of the structure represented by formula (S-5) are shown below, but the present invention is not limited thereto. In the following structural formulae, * represents the same as * in formula (S-5), and the subscript of the brackets indicates the number of repetitions.
Specific examples of the compound C include G-1 to G-16 described in Examples below.
Among G-1 to G-16 above, G-1, G-2, G-5, and G-6 correspond to the compound C-1.
G-3, G-4, G-11, and G-12 correspond to the compound C-2.
G-7 to G-10 and G-13 to G-16 correspond to the compound C-3.
The difference in SP (solubility parameter) value between the compound A and the compound C is preferably 5 (MPa)½ or less, more preferably 3 (MPa)½ or less, and still more preferably 1 (MPa)½ or less.
In the present invention, the SP value is a value determined by the Okitsu method. The Okitsu method is one of well-known methods for calculating the SP value and is described in detail in, for example, Journal of the Adhesion Society of Japan, Vol. 29, No. 6 (1993), pp. 249 to 259.
The weight-average molecular weight of the compound C is preferably 500 to 15,000, more preferably 700 to 8,000, and still more preferably 900 to 5,000.
The content of the compound C used in the present invention is, for example, 0.01% to 15% by mass, preferably 0.1% to 12% by mass, and more preferably 0.2% to 7% by mass relative to the total solid content of the curable composition for imprinting. When two or more compounds C are used, the total amount thereof is preferably within the range described above.
A ratio of the total mass of the compound C to the total mass of the compound A included in the composition (total mass of compound C/total mass of compound A × 100) is preferably 0.2% to 20% by mass, more preferably 0.5% to 15% by mass, and still more preferably 1.0% to 10% by mass in view of mold releasability.
The curable composition for imprinting according to the present invention may further include a mold release agent.
The content of the mold release agent is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, and particularly preferably 0.6% by mass or more relative to the total solid content of the composition. The upper limit is preferably less than 1.0% by mass, more preferably 0.9% by mass or less, and still more preferably 0.85% by mass or less.
When the content of the mold release agent is equal to or more than the lower limit, mold releasability is satisfactory, and it is possible to prevent peeling of the cured film and mold damage during mold release. When the content is equal to or less than the upper limit, a good resolution can be realized without causing an excessive decrease in pattern strength at the time of curing due to the influence of the mold release agent.
One or a plurality of mold release agents may be used. When a plurality of mold release agents are used, the total amount thereof is within the range described above.
The type of mold release agent is not particularly limited, but the mold release agent preferably segregates at the interface with the mold and has a function of effectively promoting release from the mold. In the present invention, preferably, the mold release agent does not substantially contain fluorine atoms or silicon atoms. The phrase “does not substantially contain” means that the total amount of fluorine atoms and silicon atoms is 1% by mass or less, preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and still more preferably 0.01% by mass or less of the mold release agent. It is preferable to use a mold release agent that does not substantially contain fluorine atoms or silicon atoms from the viewpoint of making the curable composition for imprinting excellent in process resistance to, for example, etching while realizing high mold releasability of a film thereof.
Specifically, the mold release agent used in the present invention is preferably a surfactant. Alternatively, the mold release agent is preferably an alcohol compound having at least one hydroxy group at a terminal or a compound having a (poly)alkylene glycol structure in which hydroxy groups are etherified ((poly)alkylene glycol compound). The surfactant and the (poly)alkylene glycol compound are preferably non-polymerizable compounds having no polymerizable groups. The term “(poly)alkylene glycol” means that the (poly)alkylene glycol may have either a single alkylene glycol structure or a structure in which a plurality of alkylene glycol structures are repeatedly linked together.
The surfactant that can be used as the mold release agent in the present invention is preferably a nonionic surfactant.
A nonionic surfactant is a compound having at least one hydrophobic moiety and at least one nonionic hydrophilic moiety. The hydrophobic moiety and the hydrophilic moiety may each be located at a terminal of the molecule or may be located inside the molecule. The hydrophobic moiety is composed of, for example, a hydrocarbon group, and the number of carbon atoms of the hydrophobic moiety is preferably 1 to 25, more preferably 2 to 15, still more preferably 4 to 10, and even more preferably 5 to 8. The nonionic hydrophilic moiety preferably has at least one group selected from the group consisting of an alcoholic hydroxy group, a phenolic hydroxy group, ether groups (preferably a (poly)alkyleneoxy group and a cyclic ether group), an amide group, an imide group, a ureido group, a urethane group, a cyano group, a sulfonamide group, a lactone group, a lactam group, and a cyclocarbonate group. Of these, a compound having an alcoholic hydroxy group or an ether group (preferably a (poly)alkyleneoxy group or a cyclic ether group) is more preferred.
A preferred mold release agent used in the curable composition for imprinting according to the present invention may be an alcohol compound having at least one hydroxy group at a terminal or a (poly)alkylene glycol compound in which hydroxy groups are etherified, as described above.
Specifically, the (poly)alkylene glycol compound preferably has an alkyleneoxy group or a polyalkyleneoxy group, and more preferably has a (poly)alkyleneoxy group including an alkylene group having 1 to 6 carbon atoms. Specifically, the (poly)alkylene glycol compound preferably has a (poly)ethyleneoxy group, a (poly)propyleneoxy group, a (poly)butyleneoxy group, or a mixed structure thereof, more preferably has a (poly)ethyleneoxy group, a (poly)propyleneoxy group, or a mixed structure thereof, and still more preferably has a (poly)propyleneoxy group. The (poly)alkylene glycol compound may be substantially composed only of a (poly)alkyleneoxy group except for a terminal substituent. Herein, “substantially” means that the content of components other than the (poly)alkyleneoxy group is 5% by mass or less, and preferably 1% by mass or less, based on the total mass. In particular, a compound substantially composed only of a (poly)propyleneoxy group is preferably included as the (poly)alkylene glycol compound.
The number of repetitions of the alkyleneoxy group in the (poly)alkylene glycol compound is preferably 3 to 100, more preferably 4 to 50, still more preferably 5 to 30, and even more preferably 6 to 20.
In the (poly)alkylene glycol compound, as long as a hydroxy group at one terminal is etherified, the remaining terminal may be composed of a hydroxy group, or the hydrogen atom of the terminal hydroxy group may be substituted. The group with which the hydrogen atom of the terminal hydroxy group may be substituted is preferably an alkyl group (i.e., (poly)alkylene glycol alkyl ether) or an acyl group (i.e., a (poly)alkylene glycol ester). A compound having a plurality of (preferably two or three) (poly)alkylene glycol chains via a linking group can also be preferably used.
Preferred specific examples of the (poly)alkylene glycol compound include polyethylene glycol, polypropylene glycol (for example, manufactured by FUJIFILM Wako Pure Chemical Corporation), and mono- or dimethyl ethers, mono- or dibutyl ethers, mono- or dioctyl ethers, mono- or dicetyl ethers, monostearic acid esters, monooleic acid esters, polyoxyethylene glyceryl ethers, polyoxypropylene glyceryl ethers, polyoxyethylene lauryl ethers, and trimethyl ethers thereof.
The (poly)alkylene glycol compound is preferably a compound represented by the following formula (P1) or (P2).
RP1 in the formulae is an alkylene group which may be chain-like or cyclic and may be linear or branched (and which preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms). RP2 and RP3 are each a hydrogen atom or an alkyl group which may be chain-like or cyclic and may be linear or branched (and which preferably has 1 to 36 carbon atoms, more preferably 2 to 24 carbon atoms, and still more preferably 3 to 12 carbon atoms), p is preferably an integer of 1 to 24, and more preferably an integer of 2 to 12.
RP4 is a q-valent linking group, is preferably a linking group composed of an organic group, and is preferably a linking group composed of a hydrocarbon. Specific examples of the linking group composed of a hydrocarbon include a linking group having an alkane structure (preferably having 1 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, and still more preferably 2 to 6 carbon atoms), a linking group having an alkene structure (preferably having 2 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, and still more preferably 2 to 6 carbon atoms), and a linking group having an aryl structure (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms).
q is preferably an integer of 2 to 8, more preferably an integer of 2 to 6, and still more preferably an integer of 2 to 4.
The weight-average molecular weight of the alcohol compound or the (poly)alkylene glycol compound used as the mold release agent is preferably 150 to 6,000, more preferably 200 to 3,000, still more preferably 250 to 2,000, and even more preferably 300 to 1,200.
Examples of commercially available products of the (poly)alkylene glycol compound that can be used in the present invention include OLFINE E1010 (manufactured by Nissin Chemical Industry Co., Ltd.) and Brij35 (manufactured by Kishida Chemical Co., Ltd.). Solvent
The curable composition for imprinting according to the present invention may include a solvent.
When a curable composition for imprinting, the curable composition including a solvent, is used, a curable film can be obtained by, for example, removing the solvent by drying.
In the present invention, when the curable composition for imprinting includes a solvent, the content of the solvent is preferably 90.0% to 99.0% by mass, more preferably 92.0% to 99.0% by mass, and still more preferably 95.0% to 99.0% by mass relative to the total mass of the curable composition for imprinting.
The solvent included in the curable composition for imprinting is preferably a solvent having a boiling point of 80° C. to 200° C. at 1 atm.
The type of solvent is not particularly limited, but a solvent having at least one of an ester structure, a ketone structure, a hydroxy group, or an ether structure is preferred, and examples thereof include propylene glycol monomethyl ether acetate, cyclohexanone, 2-heptanone, gamma-butyrolactone, propylene glycol monomethyl ether, and ethyl lactate.
These solvents may be used alone or as a mixture thereof.
Of these, a solvent containing propylene glycol monomethyl ether acetate is most preferable in view of coating uniformity.
The curable composition for imprinting according to the present invention may include additives other than the compounds A to C, the mold release agent, and the solvent described above. Other additives such as a surfactant, a sensitizer, an antioxidant, and a polymerization inhibitor may be included.
Specific examples of the other additives that are included in the curable composition for imprinting and that can be used in the present invention include additives included in compositions described in JP2013-036027A, JP2014-090133A, and JP2013-189537A, the contents of which are incorporated herein. In addition, with regard to the preparation of the curable composition for imprinting and the method for producing a pattern, reference can be made to the description of the above publications, the contents of which are incorporated herein.
The molar quantity of radical polymerizable groups contained with respect to the total solid content of the curable composition for imprinting is preferably 0.03 to 5.00 mol/g, more preferably 0.05 to 4.50 mol/g, and still more preferably 0.08 to 4.00 mol/g.
The viscosity of a composition excluding the solvent from the curable composition for imprinting (that is, a composition prepared by mixing components (solid components) other than the solvent in the curable composition for imprinting) is preferably 20.0 mPa·s or less, more preferably 15.0 mPa·s or less, still more preferably 11.0 mPa·s or less, and even more preferably 9.0 mPa·s or less. The lower limit of the viscosity is not particularly limited, and may be, for example, 5.0 mPa·s or more. The viscosity can be measured by a publicly known method and measured, for example, according to the following method.
The viscosity is measured using an E-type rotational viscometer RE85L manufactured by Toki Sangyo Co., Ltd. and a standard cone rotor (1°34’ × R24) while the temperature of a sample cup is adjusted to 23° C. The viscosity is represented in units of mPa·s. Other details regarding the measurement are based on JISZ8803:2011. Two samples are prepared for one level, and each sample is measured three times. The arithmetic mean value of the total of six measurements is adopted as the evaluation value.
The surface tension (yResist) of the composition excluding the solvent from the curable composition for imprinting is preferably 28.0 mN/m or more, more preferably 30.0 mN/m or more, and may be 32.0 mN/m or more. The use of a composition having a high surface tension increases the capillary force and enables a mold pattern to be filled with the composition at a high speed. The upper limit of the surface tension is not particularly limited, but is preferably 40.0 mN/m or less, more preferably 38.0 mN/m or less, and may be 36.0 mN/m or less from the viewpoints of the relationship with the adhesive layer and imparting inkjet suitability.
The surface tension of the composition excluding the solvent from the curable compositions for imprinting is measured at 23° C. with a SURFACE TENSIOMETER CBVP-A3 manufactured by Kyowa Interface Science Co., Ltd. using a glass plate.
The Ohnishi parameter of the composition excluding the solvent from the curable composition for imprinting is preferably 5.0 or less, more preferably 4.0 or less, and still more preferably 3.7 or less. The lower limit of the Ohnishi parameter of the composition excluding the solvent from the curable composition for imprinting is not particularly specified, and may be, for example, 1.0 or more, or 2.0 or more.
The Ohnishi parameter can be determined for the solid components of the curable composition for imprinting by substituting the numbers of carbon atoms, hydrogen atoms, and oxygen atoms of all constituent components into the following formula.
Ohnishi parameter = sum of the number of carbon atoms, hydrogen atoms, and oxygen atoms/(number of carbon atoms - number of oxygen atoms)
A known storage container can be used as a storage container for the curable composition for imprinting according to the present invention. As the storage container, it is also preferable to use a multi-layer bottle in which the inner wall of the container is formed of six layers composed of six types of resins or a bottle having a seven-layer structure composed of six types of resins for the purpose of suppressing the mixing of impurities into the raw materials or the composition. Examples of such a container include containers described in JP2015-123351A.
A cured product according to the present invention is a cured product obtained by curing the curable composition for imprinting according to the present invention.
The cured product according to the present invention is preferably a patterned cured product (imprint pattern).
A surface free energy of the cured product according to the present invention is preferably 10 to 70 mJ/m2, more preferably 15 to 60 mJ/m2, and still more preferably 20 to 50 mJ/m2.
The surface free energy ya is a value obtained by the following mathematical expression (1).
In mathematical expression (1), yad and yaP represent a dispersive component and a polar component, respectively, of the surface free energy of an adhesive film surface derived on the basis of the Kaelble-Uy theory.
In the measurement of the surface free energy, first, a plurality of solvents having known dispersive components and polar components of the surface free energy are each dropped on a cured product formed on a substrate such as a glass plate, and the contact angle of each of the solvents is measured. Next, each measured contact angle is applied to the following mathematical expression (1-2), and simultaneous equations related to yad and yaP of the adhesive film are solved to obtain ya.
In mathematical expression (1-2),
For the measurement of the contact angle, for example, a fully automatic contact angle meter DMo-901 (manufactured by Kyowa Interface Science Co., Ltd.) can be used. In the measurement of the surface free energy, the atmosphere is, for example, at an atmospheric pressure, and the temperature is, for example, 23° C. In applying the Kaelble-Uy theory, water, diiodomethane, formamide, oleic acid, and n-hexadecane can be used as the solvents whose dispersive component and the polar component of the surface free energy are known. To determine the surface free energy of a solid surface on the basis of the Kaelble-Uy theory, at least two solvents are necessary. A combination of water and diiodomethane is preferentially used in the present invention. If there is a solvent for which the measurement of the contact angle is impossible or not practical for some reasons, the solvent is changed to a solvent for which the measurement can be practically performed. The solvent used according to the change is successively selected from the group consisting of formamide, oleic acid, and n-hexadecane in accordance with the order of priority. The order of priority of these solvents is formamide > oleic acid > n-hexadecane. For details of the Kaelble-Uy theory, reference can be made to, for example, Journal of the Adhesion Society of Japan, Vol. 52, No. 6 (2016), pp. 171 to 175, the contents of which are incorporated herein.
The surface elastic modulus of the cured product according to the present invention is preferably 0.5 to 3.0 GPa, more preferably 0.6 to 2.5 GPa, and still more preferably 0.7 to 2.0 GPa. The surface elastic modulus is measured with an atomic force microscope (AFM). A method for producing an imprint pattern will now be described.
A method for producing an imprint pattern according to the present invention includes an application step of applying the curable composition for imprinting according to the present invention to a member to be coated selected from the group consisting of a support and a mold,
The method for producing an imprint pattern according to the present invention includes an application step of applying the curable composition for imprinting according to the present invention to a member to be coated selected from the group consisting of a support and a mold.
In the application step, one member selected from the group consisting of a support and a mold is selected as a member to be coated, and the curable composition for imprinting according to the present invention is applied onto the selected member to be coated.
One selected from the group consisting of the support and the mold serves as a member to be coated, and the other serves as a contact member.
That is, in the application step, the curable composition for imprinting according to the present invention may be applied to a support and then brought into contact with a mold, or may be applied to a mold and then brought into contact with a support (which may have, for example, an adhesive layer described later).
With regard to the support, reference can be made to the description in paragraph 0103 of JP2010-109092A (corresponding U.S. Application is US2011/0183127A), the contents of which are incorporated herein. Specific examples thereof include silicon substrates, glass substrates, sapphire substrates, silicon carbide substrates, gallium nitride substrates, metallic aluminum substrates, amorphous aluminum oxide substrates, polycrystalline aluminum oxide substrates, and substrates made of GaAsP, GaP, AlGaAs, InGaN, GaN, AlGaN, ZnSe, AlGaInP, or ZnO. Specific examples of the material of the glass substrates include aluminosilicate glass, aluminoborosilicate glass, and barium borosilicate glass. In the present invention, the substrate is preferably a silicon substrate.
The support is preferably a member including an adhesive layer on a surface to which the curable composition for imprinting is to be applied.
The adhesive layer is preferably an adhesive layer formed by applying, to the support, a composition for forming an adhesive layer described below.
The support may further include a liquid film described below on a surface of the adhesive layer opposite to a surface in contact with the support.
The liquid film is preferably a liquid film formed by applying, onto the adhesive layer, a composition for forming a liquid film described below.
As the adhesive layer, for example, those described in paragraphs 0017 to 0068 of JP2014-024322A and paragraphs 0016 to 0044 of JP2013-093552A, adhesive layers described in JP2014-093385A, and adhesive layers described in JP2013-202982A can be used, and the contents thereof are incorporated herein.
In the present invention, the mold is not particularly limited. With regard to the mold, reference can be made to the description in paragraphs 0105 to 0109 of JP2010-109092A (corresponding U.S. Application is US2011/0183127A), the contents of which are incorporated herein. The mold used in the present invention is preferably a quartz mold. The pattern (line width) of the mold used in the present invention preferably has a size of 50 nm or less. The pattern of the mold can be formed according to the desired processing accuracy by, for example, photolithography or an electron-beam drawing method; however, the method for producing a mold pattern is not particularly limited in the present invention.
A mold with which an imprint pattern including any shape of lines, holes, and pillars is formed as the imprint pattern is preferred.
In particular, a mold with which an imprint pattern including any shape of lines, holes, and pillars having a size of 100 nm or less is formed is preferred.
The method for applying the curable composition for imprinting according to the present invention to the member to be coated is not particularly specified, and generally well-known application methods can be employed. Examples thereof include a dip coating method, an air knife coating method, a curtain coating method, a wire bar coating method, a gravure coating method, an extrusion coating method, a spin coating method, a slit scan method, and an inkjet method.
Of these, an inkjet method and a spin coating method are preferred.
The curable composition for imprinting may be applied by multiple coatings.
In the method of disposing droplets by an inkjet method, the volume of each droplet is preferably about 1 to 20 pL, and the droplets are preferably disposed on a surface of the support at intervals. The interval between droplets may be appropriately determined according to the volume of each droplet, and an interval of 10 to 1,000 µm is preferred. In the case of the inkjet method, the interval between droplets is the interval between inkjet nozzles.
The inkjet method is advantageous in that the loss of the curable composition for imprinting is small.
Specific examples of the method for applying a curable composition for imprinting by an inkjet method include the methods described in, for example, JP2015-179807A and WO2016/152597A, and the methods described in these literatures can also be suitably employed in the present invention.
On the other hand, the spin coating method is advantageous in that the coating process is highly stable and the choice of usable materials is also widened.
Specific examples of the method for applying a curable composition for imprinting by a spin coating method include the methods described in, for example, JP2013-095833A and JP2015-071741A, and the methods described in these literatures can also be suitably employed in the present invention.
The method for producing an imprint pattern according to the present invention may further include a drying step of drying the curable composition for imprinting according to the present invention applied in the application step.
In particular, when a composition including a solvent is used as the curable composition for imprinting according to the present invention, the method for producing an imprint pattern according to the present invention preferably includes a drying step.
In the drying step, at least a part of the solvent included in the applied curable composition for imprinting according to the present invention is removed.
The drying method is not particularly limited, and drying by heating, drying by air blowing, or the like can be used without particular limitation, and drying by heating is preferably performed.
The heating means is not particularly limited, and a publicly known hot plate, oven, infrared heater, or the like can be used.
In the present invention, the layer formed from the curable composition for imprinting after the application step and the optional drying step and before the contact step is also referred to as a “curable film”.
The method for producing an imprint pattern according to the present invention includes a contact step of bringing, as a contact member, a member which is not selected as the member to be coated in the group consisting of the support and the mold into contact with the curable composition for imprinting (the curable film).
When a support is selected as the member to be coated in the application step, a mold serving as a contact member is brought into contact with the surface of the support to which the curable composition for imprinting according to the present invention has been applied (the surface on which the curable film has been formed) in the contact step.
When a mold is selected as the member to be coated in the application step, a support serving as a contact member is brought into contact with the surface of the mold to which the curable composition for imprinting according to the present invention has been applied (the surface on which the curable film has been formed) in the contact step.
That is, in the contact step, the curable composition for imprinting according to the present invention is present between the member to be coated and the contact member.
The details of the support and the mold are as described above.
When the curable composition for imprinting according to the present invention (the curable film) applied to the member to be coated is brought into contact with the contact member, a press contact pressure is preferably 1 MPa or less. When the press contact pressure is 1 MPa or less, the support and the mold are less likely to be deformed, and the pattern accuracy tends to improve. Furthermore, since the pressure applied is low, the size of the apparatus is likely to be reduced, which is also preferable.
It is also preferable that the contact between the curable film and the contact member be performed in an atmosphere containing helium gas or a condensable gas, or both helium gas and a condensable gas.
The method for producing an imprint pattern according to the present invention includes a curing step of curing the curable composition for imprinting to form a cured product.
The curing step is performed after the contact step and before the peeing step.
A method for producing a cured product according to the present invention includes a step of curing a curable composition for imprinting, the curable composition being obtained by a method for producing a curable composition for imprinting according to the present invention. The curing step can be performed by the same method as the curing step in the method for producing an imprint pattern according to the present invention. The cured product is preferably a cured product in a state in which the mold has been peeled off in the peeling step described later.
Examples of the curing method include curing by heating and curing by exposure. The curing method may be determined according to, for example, the type of polymerization initiator included in the curable composition for imprinting, but curing by exposure is preferred.
For example, in the case where the polymerization initiator is a photopolymerization initiator, the curable composition for imprinting can be cured by exposure in the curing step.
The exposure wavelength is not particularly limited and may be determined according to the polymerization initiator, and, for example, ultraviolet light can be used.
The exposure light source may be determined according to the exposure wavelength. Examples thereof include g-line (wavelength: 436 nm), h-line (wavelength: 405 nm), i-line (wavelength: 365 nm), broadband light (light including at least two wavelengths and selected from the group consisting of light having any of three wavelengths of g-line, h-line, and i-line, and a wavelength shorter than that of i-line, for example, a high-pressure mercury lamp in the case where no optical filter is used), semiconductor lasers (wavelength: 830 nm, 532 nm, 488 nm, 405 nm, etc.), metal halide lamps, excimer lasers, a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 193 nm), a F2 excimer laser (wavelength: 157 nm), extreme ultraviolet rays; EUV (wavelength: 13.6 nm), and electron beams.
Of these, exposure using i-line or broadband light is preferred.
The irradiation dose (exposure dose) at the time of exposure is sufficiently larger than the minimum irradiation dose necessary for curing the curable composition for imprinting. The irradiation dose necessary for curing the curable composition for imprinting can be appropriately determined by examining, for example, the amount of consumption of unsaturated bonds of the curable composition for imprinting.
The exposure dose is, for example, preferably in the range of 5 to 1,000 mJ/cm2, and more preferably in the range of 10 to 500 mJ/cm2.
The exposure illuminance is not particularly limited and may be selected depending on the relationship with the light source, but is preferably in the range of 1 to 500 mW/cm2, and more preferably in the range of 10 to 400 mW/cm2.
The exposure time is not particularly limited and may be determined in consideration of the exposure illuminance according to the exposure dose, but is preferably 0.01 to 10 seconds, and more preferably 0.5 to 1 second.
The temperature of the support at the time of exposure is usually room temperature, but the exposure may be performed while heating in order to enhance the reactivity. As a previous stage of the exposure, forming a vacuum state is effective in preventing inclusion of air bubbles, suppressing a decrease in reactivity due to inclusion of oxygen, and improving adhesiveness between the mold and the curable composition for imprinting; and therefore light irradiation may be performed in a vacuum state. The degree of vacuum at the time of exposure is preferably in the range from 10-1 Pa to ordinary pressure.
After the exposure, the curable composition for imprinting after exposure may be heated as necessary. The heating temperature is preferably 150° C. to 280° C., and more preferably 200° C. to 250° C. The heating time is preferably 5 to 60 minutes, and more preferably 15 to 45 minutes.
In the curing step, only a heating step may be performed without performing exposure. For example, in the case where the polymerization initiator is a thermal polymerization initiator, the curable composition for imprinting can be cured by heating in the curing step. Preferred embodiments of the heating temperature and the heating time in such a case are the same as the heating temperature and the heating time in the case where heating is performed after exposure.
The heating means is not particularly limited and may be the same heating means as that for heating in the drying step described above.
The method for producing an imprint pattern according to the present invention includes a peeling step of peeing the mold and the cured product from each other.
Through the peeling step, the cured product obtained in the curing step and the mold are peeled from each other to obtain a patterned cured product (also referred to as a “cured product pattern”) to which the pattern of the mold has been transferred. The obtained cured product pattern can be used in various applications as described below. The present invention is particularly advantageous in that a fine cured product pattern on the order of nanometers can be formed, and furthermore, a cured product pattern having a size of 50 nm or less, in particular, 30 nm or less can also be formed. The lower limit of the size of the cured product pattern is not particularly specified and may be, for example, 1 nm or more.
The peeling method is not particularly limited, and peeling can be performed using, for example, a mechanical peeling apparatus that is publicly known in a method for producing an imprint pattern.
A device according to the present invention includes the cured product according to the present invention. The device according to the present invention is obtained by, for example, a method for producing a device according to the present invention described below.
The method for producing a device according to the present invention includes the method for producing an imprint pattern according to the present invention.
Specific examples thereof include a method for producing a device in which a pattern (cured product pattern) formed by the method for producing an imprint pattern according to the present invention is used as a permanent film used in, for example, a liquid crystal display device (LCD) or as an etching resist (mask for lithography) for producing a semiconductor element.
In particular, the present invention discloses a method for producing a circuit board, the method including a step of obtaining a pattern (cured product pattern) by the method for producing an imprint pattern according to the present invention, and a method for producing a device including the circuit board. Furthermore, the method for producing a circuit board according to a preferred embodiment of the present invention may have a step of subjecting a substrate to etching or ion implantation using, as a mask, a pattern (cured product pattern) obtained by the above method for forming a pattern, and a step of forming an electronic member. The circuit board is preferably a semiconductor element. That is, the present invention discloses a method for producing a semiconductor device, the method including the method for producing an imprint pattern according to the present invention. Furthermore, the present invention discloses a method for producing a device, the method having a step of obtaining a circuit board by the above method for producing a circuit board, and a step of connecting the circuit board to a control mechanism configured to control the circuit board.
In addition, by forming a grid pattern on a glass substrate of a liquid crystal display device using the method for producing an imprint pattern according to the present invention, a polarizing plate having a large screen size (for example, more than 55 inches or 60 inches) with little reflection or absorption can be produced at low cost. That is, the present invention discloses a method for producing a polarizing plate, the method including the method for producing an imprint pattern according to the present invention, and a method for producing a device including the polarizing plate. For example, polarizing plates described in JP2015-132825A and WO2011/132649A can be produced. Note that 1 inch is equal to 25.4 mm.
A pattern (cured product pattern) produced by the method for producing an imprint pattern according to the present invention is also useful as an etching resist (mask for lithography). That is, the present invention discloses a method for producing a device, the method including the method for producing an imprint pattern according to the present invention, in which the obtained cured product pattern is used as an etching resist.
When the cured product pattern is used as an etching resist, in an embodiment, first, a pattern (cured product pattern) may be formed on a support by applying the method for producing an imprint pattern according to the present invention, and the support may be etched using the obtained cured product pattern as an etching mask. By etching with, for example, hydrogen fluoride in the case of wet etching or an etching gas such as CF4 in the case of dry etching, a pattern conforming to the shape of the desired cured product pattern can be formed on the support.
The pattern (cured product pattern) produced by the method for producing an imprint pattern according to the present invention can also be preferably used for producing recording media such as magnetic disks; light-receiving elements such as solid-state imaging elements; light-emitting elements such as a light emitting diode (LED) and organic electroluminescence (organic EL); optical devices such as liquid crystal display devices (LCD); optical components such as diffraction gratings, relief holograms, optical waveguides, optical filters, and microlens arrays; flat-panel display members such as thin film transistors, organic transistors, color filters, antireflection films, polarizing plates, polarizing elements, optical films, and pillar materials; nanobiodevices; immunoassay chips; deoxyribonucleic acid (DNA) separation chips; microreactors; photonic liquid crystals; and guide patterns for directed self-assembly (DSA) of block copolymers, and the like.
That is, the present invention discloses a method for producing any of these devices, the method including the method for producing an imprint pattern according to the present invention.
As described above, the formation of an adhesive layer between the support and the curable composition for imprinting provides an effect of, for example, improving the adhesiveness between the support and a layer of the curable composition for imprinting. In the present invention, the adhesive layer is obtained by applying a composition for forming an adhesive layer onto a support and then curing the composition in the same manner as in the curable composition for imprinting. Components of the composition for forming an adhesive layer will be described below.
The composition for forming an adhesive layer includes a curable component. The curable component is a component constituting the adhesive layer, and may be either a high-molecular-weight component (having a molecular weight of, for example, more than 1,000) or a low-molecular-weight component (having a molecular weight of, for example, less than 1,000). Specific examples thereof include resins and crosslinking agents. Each of these may be used alone or in combination of two or more thereof.
The total content of the curable component in the composition for forming an adhesive layer is not particularly limited, but is preferably 50% by mass or more in the total solid content, more preferably 70% by mass or more in the total solid content, and still more preferably 80% by mass or more in the total solid content. The upper limit is not particularly limited, but is preferably 99.9% by mass or less.
The concentration of the curable component in the composition for forming an adhesive layer (the composition including a solvent) is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more. The upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 1% by mass or less, and even more preferably less than 1% by mass.
Publicly known resins can be widely used as the resin in the composition for forming an adhesive layer. The resin used in the present invention preferably has at least one of a radical polymerizable group or a polar group and more preferably has both a radical polymerizable group and a polar group.
When the resin has a radical polymerizable group, an adhesive layer with good strength is provided. When the resin has a polar group, adhesiveness to the support is improved. Furthermore, in the case where a crosslinking agent is blended, the crosslinked structure formed after curing can be made stronger to improve the strength of the resulting adhesive layer.
The radical polymerizable group preferably includes an ethylenically unsaturated bond-containing group. Examples of the ethylenically unsaturated bond-containing group include a (meth)acryloyl group (preferably a (meth)acryloyloxy group and a (meth)acryloylamino group), a vinyl group, a vinyloxy group, an allyl group, a methylallyl group, a propenyl group, a butenyl group, a vinylphenyl group, and a cyclohexenyl group. A (meth)acryloyl group and a vinyl group are preferred, a (meth)acryloyl group is more preferred, and a (meth)acryloyloxy group is still more preferred. The ethylenically unsaturated bond-containing group defined here is referred to as Et.
The polar group is preferably at least one of an acyloxy group, a carbamoyloxy group, a sulfonyloxy group, an acyl group, an alkoxycarbonyl group, an acylamino group, a carbamoyl group, an alkoxycarbonylamino group, a sulfonamide group, a phosphate group, a carboxy group, or a hydroxy group, more preferably at least one of an alcoholic hydroxy group, a phenolic hydroxy group, or a carboxy group, and still more preferably an alcoholic hydroxy group or a carboxy group. The polar group defined here is referred to as a polar group Po. The polar group is preferably a nonionic group.
The resin in the composition for forming an adhesive layer may further include a cyclic ether group. Examples of the cyclic ether group include an epoxy group and an oxetanyl group, and an epoxy group is preferred. The cyclic ether group defined here is referred to as a cyclic ether group Cyt.
Examples of the resin include (meth)acrylic resins, vinyl resins, novolac resins, phenolic resins, melamine resins, urea resins, epoxy resins, and polyimide resins. The resin is preferably at least one of a (meth)acrylic resin, a vinyl resin, or a novolac resin.
The weight-average molecular weight of the resin is preferably 4,000 or more, more preferably 6,000 or more, and still more preferably 8,000 or more. The upper limit is preferably 1,000,000 or less, and may be 500,000 or less.
The resin preferably has at least one of constitutional units represented by the following formulae (1) to (3).
In the formulae, R1 and R2 are each independently a hydrogen atom or a methyl group. R21 and R3 are each independently a substituent. L1, L2, and L3 are each independently a single bond or a linking group. n2 is an integer of 0 to 4. n3 is an integer of 0 to 3. Q1 is an ethylenically unsaturated bond-containing group or a cyclic ether group. Q2 is an ethylenically unsaturated bond-containing group, a cyclic ether group, or a polar group.
R1 and R2 are preferably methyl groups.
R21 and R3 are each independently preferably the substituent described above.
When a plurality of R21 are present, they may be linked together to form a ring structure. In the present specification, the term “link” means not only a continuous form in which atoms are bonded together but also a condensed (fused ring) form in which some of the atoms are lost. Unless otherwise specified, an oxygen atom, a sulfur atom, or a nitrogen atom (amino group) may be contained in the linked ring structure. Examples of the ring structure to be formed include aliphatic hydrocarbon rings (the following given as examples are referred to as ring Cf) (e.g., a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, and a cyclohexenyl group), aromatic hydrocarbon rings (the following given as examples are referred to as ring Cr) (e.g., a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring), nitrogen-containing heterocycles (the following given as examples are referred to as ring Cn) (e.g., a pyrrole ring, an imidazole ring, a pyrazole ring, a pyridine ring, a pyrroline ring, a pyrrolidine ring, an imidazolidine ring, a pyrazolidine ring, a piperidine ring, a piperazine ring, and a morpholine ring), oxygen-containing heterocycles (the following given as examples are referred to as ring Co) (e.g., a furan ring, a pyran ring, an oxirane ring, an oxetane ring, a tetrahydrofuran ring, a tetrahydropyran ring, and a dioxane ring), and sulfur-containing heterocycles (the following given as examples are referred to as ring Cs) (e.g., a thiophene ring, a thiirane ring, a thietane ring, a tetrahydrothiophene ring, and a tetrahydrothiopyran ring).
When a plurality of R3 are present, they may be linked together to form a ring structure. Examples of the ring structure to be formed include ring Cf, ring Cr, ring Cn, ring Co, and ring Cs.
L1, L2, and L3 are each independently preferably a single bond or a linking group L described below. In particular, a single bond, or an alkylene group or (oligo)alkyleneoxy group defined by the linking group L is preferred, and an alkylene group is more preferred. The linking group L preferably has the polar group Po as a substituent. An embodiment in which an alkylene group has a hydroxy group as a substituent is also preferred. In the present specification, the term “(oligo)alkyleneoxy group” means a divalent linking group having at least one “alkyleneoxy” which is a constitutional unit. The number of carbon atoms of the alkylene chain in the constitutional unit may be the same or different for each constitutional unit.
n2 is preferably 0 or 1, and more preferably 0. n3 is preferably 0 or 1, and more preferably 0.
Q1 is preferably the ethylenically unsaturated bond-containing group Et.
Q2 is preferably a polar group, and preferably an alkyl group having an alcoholic hydroxy group.
The resin may further include at least one constitutional unit selected from the group consisting of the following constitutional units (11), (21), and (31). In particular, in the resin included in the present invention, the constitutional unit (11) is preferably combined with the constitutional unit (1), the constitutional unit (21) is preferably combined with the constitutional unit (2), and the constitutional unit (31) is preferably combined with the constitutional unit (3).
In the formulae, R11 and R22 are each independently a hydrogen atom or a methyl group. R17 is a substituent. R27 is a substituent. n21 is an integer of 0 to 5. R31 is a substituent, and n31 is an integer of 0 to 3.
R11 and R22 are preferably methyl groups.
R17 is preferably a group including a polar group or a group including a cyclic ether group. When R17 is a group including a polar group, R17 is preferably a group including the polar group Po described above, and more preferably the polar group Po or a substituent substituted with the polar group Po. When R 17 is a group including a cyclic ether group, R 17 is preferably a group including the cyclic ether group Cyt described above, and more preferably a substituent substituted with the cyclic ether group Cyt.
R27 is a publicly known substituent, and at least one R27 is preferably a polar group. n21 is preferably 0 or 1, and more preferably 0. When a plurality of R27 are present, they may be linked together to form a ring structure. Examples of the ring structure to be formed include examples of ring Cf, ring Cr, ring Cn, ring Co, and ring Cs.
R31 is preferably a publicly known substituent. n31 is an integer of 0 to 3, preferably 0 or 1, and more preferably 0. When a plurality of R31 are present, they may be linked together to form a ring structure. Examples of the ring structure to be formed include examples of ring Cf, ring Cr, ring Cn, ring Co, and ring Cs.
Examples of the linking group L include an alkylene group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and still more preferably 1 to 6 carbon atoms), an alkenylene group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably 2 to 3 carbon atoms), an (oligo)alkyleneoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms of an alkylene group in one constitutional unit, and preferably having a number of repetitions of 1 to 50, more preferably 1 to 40, and still more preferably 1 to 30), an arylene group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms), an oxygen atom, a sulfur atom, a sulfonyl group, a carbonyl group, a thiocarbonyl group, —NRN—, and linking groups formed by a combination thereof. The alkylene group, the alkenylene group, and the alkyleneoxy group may have a substituent. For example, the alkylene group may have a hydroxy group.
The linking chain length of the linking group L is preferably 1 to 24, more preferably 1 to 12, and still more preferably 1 to 6. The linking chain length means the number of atoms located on the shortest path among atomic groups involved in the linking. For example, in the case of —CH2—(C═O)—O—, the linking chain length is 3.
The alkylene group, the alkenylene group, and the (oligo)alkyleneoxy group defined as the linking group L may be chain-like or cyclic, and may be linear or branched.
The atoms constituting the linking group L preferably include a carbon atom and a hydrogen atom, and if necessary, a heteroatom (for example, at least one selected from the group consisting of an oxygen atom, a nitrogen atom, and a sulfur atom). The number of carbon atoms in the linking group is preferably 1 to 24, more preferably 1 to 12, and still more preferably 1 to 6. The number of hydrogen atoms may be determined in accordance with the number of carbon atoms and the like. The numbers of heteroatoms, i.e., the number of oxygen atoms, the number of nitrogen atoms, and the number of sulfur atoms are each independently preferably 0 to 12, more preferably 0 to 6, and still more preferably 0 to 3.
The resin may be synthesized by a typical method. For example, the resin having the constitutional unit represented by formula (1) can be appropriately synthesized by a publicly known method relating to addition polymerization of an olefin. The resin having the constitutional unit represented by formula (2) can be appropriately synthesized by a publicly known method relating to addition polymerization of styrene. The resin having the constitutional unit represented by formula (3) can be appropriately synthesized by a publicly known method relating to the synthesis of a phenolic resin.
The above resins may be used alone or in combination of two or more thereof.
In addition to the resins described above, resins described in paragraphs 0016 to 0079 of WO2016/152600A, paragraphs 0025 to 0078 of WO2016/148095A, paragraphs 0015 to 0077 of WO2016/031879A, and paragraphs 0015 to 0057 of WO2016/027843A can be used as the resin serving as the curable component, and the contents thereof are incorporated herein.
The crosslinking agent in the composition for forming an adhesive layer is not particularly limited as long as the crosslinking agent promotes curing by crosslinking reaction. In the present invention, the crosslinking agent preferably forms a crosslinked structure due to a reaction with a polar group in the resin. The use of such a crosslinking agent causes the resin to be more strongly bonded to provide a stronger film.
Examples of the crosslinking agent include epoxy compounds (compounds having an epoxy group), oxetanyl compounds (compounds having an oxetanyl group), alkoxymethyl compounds (compounds having an alkoxymethyl group), methylol compounds (compounds having a methylol group), and blocked isocyanate compounds (compounds having a blocked isocyanate group). Alkoxymethyl compounds (compounds having an alkoxymethyl group) are preferred because strong bonds can be formed at low temperatures.
The composition for forming an adhesive layer may include other components in addition to the components described above.
Specifically, the composition for forming an adhesive layer may include at least one of, for example, a solvent, a thermal acid generator, an alkylene glycol compound, a polymerization initiator, a polymerization inhibitor, an antioxidant, a leveling agent, a thickener, or a surfactant. With regard to the above components, components described in JP2013-036027A, JP2014-090133A, and JP2013-189537A can be used. With regard to, for example, the content, reference can be made to the description of the above publications.
In the present invention, the composition for forming an adhesive layer particularly preferably includes a solvent (hereinafter, also referred to as a “solvent for an adhesive layer”). The solvent is preferably, for example, a compound that is liquid at 23° C. and that has a boiling point of 250° C. or lower. The composition for forming an adhesive layer includes the solvent for an adhesive layer in an amount of preferably 99.0% by mass or more, more preferably 99.2% by mass or more, and may include the solvent for an adhesive layer in an amount of 99.4% by mass or more. That is, the total solid content concentration of the composition for forming an adhesive layer is preferably 1% by mass or less, more preferably 0.8% by mass or less, and still more preferably 0.6% by mass or less. The lower limit is preferably more than 0% by mass, more preferably 0.001% by mass or more, still more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more. When the proportion of the solvent is within the range described above, the film thickness at the time of film formation is kept small, and pattern formability in an etching process tends to improve.
Only one solvent or two or more solvents may be included in the composition for forming an adhesive layer. When two or more solvents are included, the total amount thereof is preferably within the range described above.
The boiling point of the solvent for an adhesive layer is preferably 230° C. or lower, more preferably 200° C. or lower, still more preferably 180° C. or lower, even more preferably 160° C. or lower, and yet still more preferably 130° C. or lower. The lower limit is preferably 23° C., and more preferably 60° C. or higher. A boiling point within the range described above is preferred because the solvent can be easily removed from the adhesive layer.
The solvent for an adhesive layer is preferably an organic solvent. The solvent is preferably a solvent having at least one of an ester group, a carbonyl group, a hydroxy group, or an ether group. Of these, an aprotic polar solvent is preferably used.
Of these, preferred examples of the solvent for an adhesive layer include alkoxy alcohols, propylene glycol monoalkyl ether carboxylates, propylene glycol monoalkyl ethers, lactates, acetates, alkoxypropionic acid esters, chain ketones, cyclic ketones, lactones, and alkylene carbonates. Propylene glycol monoalkyl ethers and lactones are particularly preferred.
In the present invention, it is also preferable to form a liquid film on the adhesive layer using a composition for forming a liquid film, the composition including a radical polymerizable compound that is liquid at 23° C. and 1 atm. In the present invention, the liquid film is obtained by applying a composition for forming a liquid film onto a support and then drying the composition in the same manner as in the curable composition for imprinting. The formation of such a liquid film provides an effect of further improving the adhesiveness between the support and the curable composition for imprinting, and also improving the wettability of the curable composition for imprinting on the support. The composition for forming a liquid film will be described below.
The viscosity of the composition for forming a liquid film is preferably 1,000 mPa·s or less, more preferably 800 mPa·s or less, still more preferably 500 mPa·s or less, and even more preferably 100 mPa·s The lower limit of the viscosity is not particularly limited, and may be, for example, 1 mPa·s or more. The viscosity is measured according to the following method.
The viscosity is measured using an E-type rotational viscometer RE85L manufactured by Toki Sangyo Co., Ltd. and a standard cone rotor (1°34’ × R24) while the temperature of a sample cup is adjusted to 23° C. The viscosity is represented in units of mPa·s. Other details regarding the measurement are based on JISZ8803:2011. Two samples are prepared for one level, and each sample is measured three times. The arithmetic mean value of the total of six measurements is adopted as the evaluation value.
The composition for forming a liquid film includes a radical polymerizable compound (radical polymerizable compound A) which is liquid at 23° C. and 1 atm.
The viscosity of the radical polymerizable compound A at 23° C. is preferably 1 to 100,000 mPa·s. The lower limit is preferably 5 mPa·s or more, and more preferably 11 mPa·s or more. The upper limit is preferably 1,000 mPa·s or less, and more preferably 600 mPa·s or less.
The radical polymerizable compound A may be a monofunctional radical polymerizable compound having only one radical polymerizable group in one molecule, or may be a polyfunctional radical polymerizable compound having two or more radical polymerizable groups in one molecule. A monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound may be used in combination. In particular, the radical polymerizable compound A included in the composition for forming a liquid film preferably includes a polyfunctional radical polymerizable compound, more preferably includes a radical polymerizable compound including 2 to 5 radical polymerizable groups in one molecule, still more preferably includes a radical polymerizable compound including 2 to 4 radical polymerizable groups in one molecule, and particularly preferably includes a radical polymerizable compound including two radical polymerizable groups in one molecule, for the reason of suppressing pattern collapse.
The radical polymerizable compound A preferably includes at least one of an aromatic ring (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms) or an alicyclic ring (preferably having 3 to 24 carbon atoms, more preferably 3 to 18 carbon atoms, and still more preferably 3 to 6 carbon atoms) and more preferably includes an aromatic ring. The aromatic ring is preferably a benzene ring. The radical polymerizable compound A preferably has a molecular weight of 100 to 900.
Examples of radical polymerizable groups in the radical polymerizable compound A include ethylenically unsaturated bond-containing groups such as a vinyl group, an allyl group, and a (meth)acryloyl group, and a (meth)acryloyl group is preferred.
The radical polymerizable compound A is also preferably a compound represented by the following formula (I-1).
L20 is a 1 + q2 valent linking group, and examples thereof include 1 + q2 valent linking groups including a group having an alkane structure (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms), a group having an alkene structure (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably 2 or 3 carbon atoms), a group having an aryl structure (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably 6 to 10 carbon atoms), a group having a heteroaryl structure (preferably having 1 to 22 carbon atoms, more preferably 1 to 18 carbon atoms, and still more preferably 1 to 10 carbon atoms, where examples of heteroatoms include a nitrogen atom, a sulfur atom, and an oxygen atom, and a five-membered ring, a six-membered ring, or a seven-membered ring is preferred), or a group of a combination of the foregoing. Examples of the group of a combination of two aryl groups include groups having a structure of biphenyl, diphenylalkane, biphenylene, indene, or the like. Examples of the group of a combination of a group having a heteroaryl structure and a group having an aryl structure include groups having a structure of indole, benzimidazole, quinoxaline, carbazole, or the like.
L20 is preferably a linking group including at least one selected from the group consisting of a group having an aryl structure and a group having a heteroaryl structure, and more preferably a linking group including a group having an aryl structure.
R21 and R22 each independently represent a hydrogen atom or a methyl group.
L21 and L22 each independently represent a single bond or the linking group L and are preferably a single bond or an alkylene group.
L20 and L21 or L22 may be bonded together with or without the linking group L therebetween to form a ring. L20, L21, and L22 may have a substituent. A plurality of substituents may be bonded together to form a ring. When a plurality of substituents are present, they may be the same or different from each other.
q2 is an integer of 0 to 5, preferably an integer of 0 to 3, more preferably an integer of 0 to 2, still more preferably 0 or 1, and particularly preferably 1.
As the radical polymerizable compound A, compounds described in paragraphs 0017 to 0024 and Examples of JP2014-090133A, compounds described in paragraphs 0024 to 0089 of JP2015-009171A, compounds described in paragraphs 0023 to 0037 of JP2015-070145A, and compounds described in paragraphs 0012 to 0039 of WO2016/152597A can also be used.
The content of the radical polymerizable compound A in the composition for forming a liquid film is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more. The upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 1% by mass or less.
The content of the radical polymerizable compound A based on the solid content of the composition for forming a liquid film is preferably 50% by mass or more, more preferably 75% by mass or more, and still more preferably 90% by mass or more. The upper limit may be 100% by mass. Such radical polymerizable compounds A may be used alone or in combination of two or more thereof. When two or more radical polymerizable compounds A are used, the total amount thereof is preferably within the range described above.
It is also preferable that the solid component of the composition for forming a liquid film be substantially composed only of the radical polymerizable compound A. The case where the solid component of the composition for forming a liquid film is substantially composed only of the radical polymerizable compound A means that the content of the radical polymerizable compound A based on the solid content of the composition for forming a liquid film is 99.9% by mass or more, more preferably 99.99% by mass or more, and still more preferably, the solid component is composed only of the polymerizable compound A.
The composition for forming a liquid film preferably includes a solvent (hereinafter may be referred to as a “solvent for a liquid film”). Examples of the solvent for a liquid film include those described in the section of the solvent for an adhesive layer, and those solvents can be used. The composition for forming a liquid film includes the solvent for a liquid film in an amount of preferably 90% by mass or more, more preferably 99% by mass or more, and may include the solvent for a liquid film in an amount of 99.99% by mass or more.
The boiling point of the solvent for a liquid film is preferably 230° C. or lower, more preferably 200° C. or lower, still more preferably 180° C. or lower, even more preferably 160° C. or lower, and yet still more preferably 130° C. or lower. The lower limit is preferably 23° C., and more preferably 60° C. or higher. A boiling point within the range described above is preferred because the solvent can be easily removed from the liquid film.
The composition for forming a liquid film may include a radical polymerization initiator. Examples of the radical polymerization initiator include thermal radical polymerization initiators and photo-radical polymerization initiators, and a photo-radical polymerization initiator is preferred. As the photo-radical polymerization initiator, any publicly known compound can be used. Examples thereof include halogenated hydrocarbon derivatives (such as a compound having a triazine skeleton, a compound having an oxadiazole skeleton, and a compound having a trihalomethyl group), acylphosphine compounds, hexaarylbiimidazole compounds, oxime compounds, organic peroxides, thio compounds, ketone compounds, aromatic onium salts, acetophenone compounds, azo compounds, azide compounds, metallocene compounds, organoboron compounds, and iron-arene complexes. For the details of these, reference can be made to the description in paragraphs 0165 to 0182 of JP2016-027357A, the contents of which are incorporated herein. Of these, acetophenone compounds, acylphosphine compounds, and oxime compounds are preferred. Examples of commercially available products include IRGACURE-OXE01, IRGACURE-OXE02, IRGACURE-127, IRGACURE-819, IRGACURE-379, IRGACURE-369, IRGACURE-754, IRGACURE-1800, IRGACURE-651, IRGACURE-907, IRGACURE-TPO, and IRGACURE-1173 (all of which are manufactured by BASF), and Omnirad 184, Omnirad TPO H, Omnirad 819, and Omnirad 1173 (all of which are manufactured by I.G.M Resins B.V).
When a radical polymerization initiator is included, the content thereof is preferably 0.1% to 10% by mass, more preferably 1% to 8% by mass, and still more preferably 2% to 5% by mass based on the solid content of the composition for forming a liquid film. When two or more radical polymerization initiators are used, the total amount thereof is preferably in the range described above.
In addition to the above, the composition for forming a liquid film may include at least one of, for example, a polymerization inhibitor, an antioxidant, a leveling agent, a thickener, or a surfactant.
Hereafter, the present invention will be more specifically described with reference to Examples. The materials, amounts thereof used, proportions, details of processes, procedures thereof, and the like described in the following Examples may be appropriately changed without departing from the gist of the present invention. Accordingly, the scope of the present invention is not limited to specific examples described below. In Examples, “part” and “%” are based on mass unless otherwise specified, and the environmental temperature (room temperature) in each step is 23° C.
In each Example and each Comparative Example, various compounds shown in tables below were mixed to prepare a curable composition for imprinting or a composition for comparison. In each composition, a component described as “-” was not added. The mixture was filtered through a 0.05 µm UPE (ultra-high-molecular-weight polyethylene resin) filter, a 0.02 µm Nylon filter, and a 0.005 µm UPE filter in this order to prepare the curable composition for imprinting or the composition for comparison. In the tables, the row of “Amount of radical polymerizable group” shows the molar quantity of radical polymerizable groups contained with respect to the total solid content of the composition.
Details of each component shown in the tables are as follows.
A methyl-based silicone resin KR-500 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) (110.8 parts), 2-hydroxyethyl acrylate (58.1 parts), and p-toluenesulfonic acid monohydrate (0.034 parts) were mixed, heated to 120° C. while bubbling a nitrogen gas containing 5% of oxygen, and caused to react for three hours under stirring while distilling off methanol generated by a condensation reaction to obtain 153.9 parts of A-1. Since the physical property values of the resulting compound were as follows, the compound was confirmed to be a polymerizable compound having alkoxysilyl groups in the molecule and containing 10% by mass or more of silicon atoms.
1H-NMR (300 MHz, CDC13) δ(ppm): 6.43 (m, CH=C), 6.13 (m, C═CH—C═O), 5.83 (m, CH=C), 4.25 (br, CH2—OC═O), 3.96 (br, CH2—O—Si), 3.50 (s, Si-OCH3), 0.15 (s, Si-CH3). The weight-average molecular weight was measured and found to be 1,650.
Into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a condenser tube, and a nitrogen gas inlet, phenyltrimethoxysilane (20.1 parts), dimethyldimethoxysilane (24.4 parts), and n-butyl acetate (107.7 parts) were charged, and the temperature was raised to 80° C. while stirring under a nitrogen gas stream. Subsequently, a mixture containing methyl methacrylate (14.5 parts), n-butyl methacrylate (2 parts), cyclohexyl methacrylate (105 parts), acrylic acid (7.5 parts), 3-methacryloyloxypropyltrimethoxysilane (4.5 parts), 2-hydroxyethyl methacrylate (15 parts), n-butyl acetate (15 parts), and tert-butyl peroxy-2-ethylhexanoate (6 parts) was added dropwise to the reaction vessel at the same temperature over four hours while stirring under a nitrogen gas stream. After stirring was further performed at the same temperature for two hours, a mixture of isopropyl phosphate (0.05 parts) and deionized water (12.8 parts) was added dropwise to the reaction vessel over five minutes, and the mixture was stirred at the same temperature for four hours to cause a hydrolytic condensation reaction of phenyltrimethoxysilane, dimethyldimethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane to proceed. The 1H-NMR analysis of the reaction product showed that almost 100% of methoxy groups in trimethoxysilyl groups of the silanemonomers in the reaction vessel were hydrolyzed. Subsequently, stirring was performed at the same temperature for 10 hours to obtain a vinyl polymer which was a reaction product having a residual amount of tert-butylperoxy-2-ethylhexanoate of 0.1% by mass or less. Subsequently, 162.5 parts of a methyl-based silicone resin KR-515 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 307 parts of the obtained vinyl polymer, stirring was performed for five minutes, 27.5 parts of deionized water was then added, and stirring was performed at 80° C. for four hours to carry out a hydrolytic condensation reaction between the reaction product and polysiloxane. The resulting reaction product was distilled under a reduced pressure of 10 to 300 kPa under a condition of 40° C. to 60° C. for two hours to remove generated methanol and water, and 150 parts of methyl ethyl ketone (MEK) and 27.3 parts of n-butyl acetate were then added to obtain 600 parts of a compound A-2 having a non-volatile content of 50.0%. The weight-average molecular weight of the compound A-2 was measured and found to be 2,000.
In a glass flask equipped with a condenser tube and a stirring blade made of Teflon (registered trademark), a methyl-based silicone resin X-40-9225 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) (110.8 parts), 2-hydroxyethyl acrylate (58.1 parts), and sulfuric acid (0.0034 parts) were mixed, heated to 120° C., and caused to react under stirring for 10 hours while distilling off methanol generated by a condensation reaction to obtain 153.9 parts of A-4. Since the physical property values of the resulting compound were as follows, the compound was confirmed to be a photosensitive resin having a group having a curable functional group.
1H-NMR (300 MHz, CDC13) δ (ppm): 6.43 (m, CH=C), 6.13 (m, C═CH—C═O), 5.83 (m, CH=C), 4.25 (br, CH2—O—C═O), 3.96 (br, CH2—O—Si), 3.50 (s, Si-OCH3), 0.15 (s, Si-CH3). The weight-average molecular weight was measured and found to be 5,100.
In the following chemical formulae, Bu represents a butyl group, Me represents a methyl group, and the subscript of the brackets indicates the number of repetitions.
R-1 to R-3: Compounds having structures below. In the following formulae, the subscript of the brackets indicates the number of repetitions.
•PGMEA: Propylene glycol monomethyl ether acetate
The composition for forming an adhesive layer described in Example 6 of JP2014-024322A was applied onto a silicon wafer by spin coating and heated with a hot plate at 220° C. for one minute to form an adhesive layer having a thickness of 5 nm. A composition for forming a pattern (a curable composition for imprinting or a composition for comparison) was applied onto the adhesive layer by a spin coating method. The thickness of the layer composed of the composition for forming a pattern was 50 µm.
Subsequently, an imprint mold was pressed against the composition for forming a pattern in a helium atmosphere. The mold used was a quartz mold having a line-and-space with a line width of 15 nm, a depth of 30 nm, and a pitch of 60 nm. Subsequently, exposure was performed from the mold surface using an extra-high pressure mercury lamp such that the exposure dose became 100 mJ/cm2, and the mold was released to obtain a pattern formed of a cured product of the composition for forming a pattern.
In the formation of the pattern, a force (mold release force F, unit: N) required to release the quartz mold was measured. The evaluation was performed in accordance with the following evaluation criteria. The evaluation results are shown in the row of “Mold releasability” in the tables. The mold release force was measured in accordance with the method of Comparative Example described in paragraphs 0102 to 0107 of JP2011-206977A.
Evaluation Criteria
A film thickness (T1) of a film immediately after preparation, the film being composed of the composition for forming a pattern and prepared in the same manner as in the evaluation of mold releasability, was measured. The wafer on which the film was formed was further left to stand at room temperature for 48 hours, and a film thickness (T2) was measured again. The difference in film thickness (ΔFT = | T1 - T2 | ) between immediately after film formation and 48 hours after film formation was examined. The evaluation was performed on the basis of the value of AFT according to the following evaluation criteria. The evaluation results are shown in the row of “Stability of coating film” in the tables.
The film thickness was measured with an ellipsometer.
The above results show that when the curable composition for imprinting according to the present invention is used, good mold releasability is achieved.
The compositions according to Comparative Examples 1 and 2 do not include the compound C. In such embodiments, the mold releasability is found to be poor.
Furthermore, an adhesive layer was formed on a silicon wafer using the composition for forming an adhesive layer by the same method as that used in the evaluation of mold releasability, and a line-and-space structure, a contact hole structure, a dual damascene structure, and a staircase structure were formed on the adhesive layer of the silicon wafer with the adhesive layer using the curable composition for imprinting according to each Example. Each silicon wafer was then dry-etched using this pattern as an etching mask, and a semiconductor element was produced using the silicon wafer. For any of the semiconductor elements, there was no problem in terms of performance. In addition, the composition for forming an adhesive layer and the curable composition for imprinting according to each Example were used to produce a semiconductor element on a substrate having a spin-on carbon (SOC) layer by the same procedure as that described above. For any of the resulting semiconductor elements, there was no problem in terms of performance.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-134049 | Aug 2021 | JP | national |
