JP5696567B2 - Radiation-sensitive composition for nanoimprint and pattern formation method - Google Patents

Description

  The present invention relates to a radiation-sensitive composition for nanoimprint and a pattern forming method.

In order to improve the degree of integration and recording density of circuits such as semiconductor elements, a finer processing technique is required. As this fine processing technique, a photolithography technique using an exposure process is known. The above photolithography technique is excellent in that a large area can be finely processed at a time, but since it does not have a resolution below the wavelength of light, it is necessary to use light having a shorter wavelength for finer processing. Necessary. Therefore, recently, a photolithography technique using short-wavelength light such as 193 nm (ArF), 157 nm (F ₂ ), and 13.5 nm (EUV) has been developed. However, when the wavelength of light is shortened, a substance that can transmit light of that wavelength is limited, and thus there is a possibility that the production of a fine structure may be limited. On the other hand, methods such as electron beam lithography and focused ion beam lithography have the disadvantage that the throughput is poor, although the resolution does not depend on the wavelength of light and a finer structure can be produced.

  Therefore, as a technique for producing a fine structure with a wavelength equal to or less than the wavelength of light at a high throughput, a mold in which a predetermined fine concavo-convex pattern is produced in advance by the above-mentioned electron beam lithography or the like is pressed against the radiation-sensitive composition applied on the substrate. There is known a nanoimprint method for transferring the irregularities of the above to the radiation-sensitive composition (see US Pat. No. 5,772,905, US Pat. No. 5,956,216 and Japanese Patent Application Laid-Open No. 2008-162190).

  However, the nanoimprint method has various problems to be solved in order to realize this. One of them is a problem of etching resistance of the radiation-sensitive composition for nanoimprint. That is, when a conventional radiation-sensitive composition for nanoimprinting is used, etching resistance is insufficient, and thus the pattern shape obtained may be disturbed during etching after transferring the fine pattern of the mold. Therefore, development of a radiation-sensitive composition for nanoimprinting that satisfies basic characteristics such as curability and is excellent in etching resistance is desired.

US Pat. No. 5,772,905 US Pat. No. 5,956,216 JP 2008-162190 A

  The present invention has been made on the basis of the circumstances as described above, and its purpose is to satisfy the basic characteristics such as curability and to be excellent in etching resistance, and to use the radiation-sensitive composition for nanoimprint, and the same. It is to provide a pattern forming method.

The invention made to solve the above problems is
Radiation sensitive nanoimprint containing a polymerizable compound containing a sulfur atom (hereinafter also referred to as “[A] polymerizable compound”) and a radiation sensitive polymerization initiator (hereinafter also referred to as “[D] polymerization initiator”). Composition.

  Since the radiation-sensitive composition for nanoimprinting of the present invention contains a polymerizable compound containing a sulfur atom and a radiation-sensitive polymerization initiator, it is excellent in etching resistance as compared with conventional radiation-sensitive compositions for nanoimprinting.

（式（１）中、Ｒ^Ａ及びＲ^Ｂは、それぞれ独立して、水素原子又はメチル基である。Ｒ^１及びＲ^２は、それぞれ独立して、炭素数１〜６のアルカンジイル基である。Ｘ^１及びＸ^２は、それぞれ独立して、−Ｓ−又は−Ｏ−である。Ｙは、−Ｓ−、−ＳＯ_２−、−ＣＯ−、炭素数１〜１２のアルカンジイル基又は炭素数７〜１２のアラルキレン基である。但し、このアルカンジイル基及びアラルキレン基のアルキレン鎖の炭素−炭素間に酸素原子又は硫黄原子を有していてもよい。また、Ｘ^１、Ｘ^２及びＹの少なくとも１つは硫黄原子を含む基である。Ａｒ^１及びＡｒ^２は、それぞれ独立して、炭素数６〜３０のアリーレン基又は炭素数７〜３０のアラルキレン基である。このアリーレン基及びアラルキレン基の水素原子の一部又は全部は、フッ素原子を含まない置換基で置換されていてもよい。ｍ及びｎは、それぞれ独立して、１〜５の整数である。ｐは、０〜１０の整数である。ｍが２以上の場合、複数のＲ^１及びＸ^１は、それぞれ同一でも異なっていてもよい。ｎが２以上の場合、複数のＲ^２及びＸ^２は、それぞれ同一でも異なっていてもよい。ｐが２以上の場合、複数のＹ及びＡｒ^２は、それぞれ同一でも異なっていてもよい。） The polymerizable compound containing a sulfur atom is preferably a compound represented by the following formula (1).

(In Formula (1), R ^A and R ^B are each independently a hydrogen atom or a methyl group. R ¹ and R ² are each independently an alkanediyl group having 1 to 6 carbon atoms. X ¹ and X ² are each independently —S— or —O—, Y is —S—, —SO ₂ —, —CO—, an alkanediyl group having 1 to 12 carbon atoms or carbon. An aralkylene group of 7 to 12. However, an oxygen atom or a sulfur atom may be present between carbon-carbons of the alkylene chain of the alkanediyl group and aralkylene group, and X ¹ , X ² and Y At least one of them is a group containing a sulfur atom, and Ar ¹ and Ar ² are each independently an arylene group having 6 to 30 carbon atoms or an aralkylene group having 7 to 30 carbon atoms. Part or all of the hydrogen atoms of the radical The moiety may be substituted with a substituent that does not contain a fluorine atom, m and n are each independently an integer of 1 to 5. p is an integer of 0 to 10. m is 2 In the above case, the plurality of R ¹ and X ¹ may be the same or different, and when n is 2 or more, the plurality of R ² and X ² may be the same or different, and p is 2. In the above case, the plurality of Y and Ar ² may be the same or different.)

  When the polymerizable compound containing a sulfur atom has the above-described characteristic structure, the radiation-sensitive composition for nanoimprinting is excellent in polymerizability, sufficiently satisfies curability, and can further improve etching resistance.

  The nanoimprint radiation-sensitive composition may further contain a polymerizable compound not containing a sulfur atom.

  The radiation-sensitive composition for nanoimprinting further contains a polymerizable compound that does not contain a sulfur atom, so that it has excellent polymerizability, can sufficiently satisfy basic properties such as curability, and is excellent in etching resistance. .

（式（２）中、Ｒ^３は、水素原子又はｓ価の有機基である。ｓは、１又は２である。Ｒ^Ｃは、水素原子又はメチル基である。ｔは、０又は１である。但し、ｓが２の場合、２つのＲ^Ｃ及びｔは、それぞれ同一でも異なっていてもよい。
式（３）中、Ｒ^４は、炭素数４〜２０の鎖状炭化水素基又は脂環式炭化水素基である。この鎖状炭化水素基及び脂環式炭化水素基の水素原子の一部又は全部はフッ素原子を含まない置換基で置換されていてもよい。Ｒ^Ｄ及びＲ^Ｅは、それぞれ独立して、水素原子又はメチル基である。） The polymerizable compound not containing a sulfur atom is at least one compound selected from the group consisting of a compound represented by the following formula (2) and a compound represented by the following formula (3) (hereinafter, “ [B] polymerizable compound ”).

(In Formula (2), R ³ is a hydrogen atom or an s-valent organic group. S is 1 or 2. R ^C is a hydrogen atom or a methyl group. T is 0 or 1. However, when s is 2, two R ^C and t may be the same or different from each other.
In formula (3), R ⁴ is a chain hydrocarbon group or alicyclic hydrocarbon group having 4 to 20 carbon atoms. Part or all of the hydrogen atoms of the chain hydrocarbon group and alicyclic hydrocarbon group may be substituted with a substituent not containing a fluorine atom. R ^D and R ^E are each independently a hydrogen atom or a methyl group. )

  By containing the polymerizable compound having the specific structure, the radiation-sensitive composition for nanoimprinting is more excellent in polymerizability, sufficiently satisfies basic characteristics such as curability, and is further excellent in etching resistance.

  It is preferable that the said radiation sensitive composition for nanoimprint further contains the compound containing a fluorine atom. By containing the compound containing a fluorine atom further, the said radiation sensitive composition for nanoimprint can fully satisfy mold release property, and is excellent also in etching tolerance.

The pattern forming method is:
(1) The process of forming a coating film on a base material using the radiation sensitive composition for nanoimprints of the present invention,
(2) a step of pressing a mold having a concavo-convex pattern on the surface against the coating film,
(3) A process of forming the pattern forming layer by exposing the coating film in a state where the mold is pressed.
(4) a step of peeling the mold from the pattern forming layer; and (5) a step of etching the pattern forming layer.

  Since the said pattern formation method uses the said radiation sensitive composition for nanoimprints which is fully satisfied with sclerosis | hardenability and is excellent also in etching tolerance, the pattern excellent in a shape can be formed efficiently.

  Here, “radiation” in the radiation-sensitive composition for nanoimprinting and the radiation-sensitive polymerization initiator refers to light having a wavelength in the ultraviolet, near-ultraviolet, far-ultraviolet, visible, infrared, or the like, electromagnetic waves, and microwaves. , Electron beam, EUV, X-ray and the like. Also included are laser beams such as a 248 nm excimer laser, a 193 nm excimer laser, and a 172 nm excimer laser. These lights may be monochrome light (single wavelength light) that has passed through an optical filter, or may be light having a plurality of different wavelengths (composite light). Here, the polymerizable compound refers to a compound having a polymerizable group and having a property of being polymerized in the radiation-sensitive composition for nanoimprinting by exposure in pattern formation. On the other hand, a non-polymerizable compound means a compound that does not have a polymerizable group and does not polymerize by exposure in pattern formation when contained in a radiation-sensitive composition for nanoimprinting. Therefore, for example, a compound such as a polymer that has already undergone the polymerization reaction is included in the non-polymerizable compound because it does not cause further polymerization reaction upon exposure even if it is included in the radiation-sensitive composition for nanoimprinting. .

  Since the radiation-sensitive composition for nanoimprinting of the present invention sufficiently satisfies basic characteristics such as curability and is excellent in etching resistance, a pattern having excellent shape can be formed.

It is a schematic diagram which shows an example of the state after forming a pattern formation layer on a board | substrate. It is a schematic diagram which shows an example of the state which has pressure-contacted the mold to the pattern formation layer. It is a schematic diagram which shows an example of the state which has exposed the pattern formation layer, pressing the mold. It is a schematic diagram which shows an example of the state after peeling a mold from a pattern formation layer. It is a schematic diagram which shows an example of the state after etching.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

<Radiosensitive composition for nanoimprint>
The radiation-sensitive composition for nanoimprinting of the present invention contains a polymerizable compound containing a sulfur atom and a radiation-sensitive polymerization initiator. The radiation-sensitive composition for nanoimprint can improve etching resistance by containing a polymerizable compound containing a sulfur atom. Moreover, it is preferable that the said radiation sensitive composition for nanoimprint further contains the polymeric compound which does not contain a sulfur atom. Furthermore, it is preferable that the said radiation sensitive composition for nanoimprints contains a nonpolymerizable compound, and as this nonpolymerizable compound, the nonpolymerizable compound containing a fluorine atom is more preferable. In addition, unless the effect of this invention is impaired, other arbitrary components other than the above can be contained. Hereinafter, each component will be described in detail.

<Polymerizable compound>
The radiation-sensitive composition for nanoimprinting contains a polymerizable compound containing a sulfur atom. Moreover, it is preferable to further contain the polymeric compound which does not contain a sulfur atom. In addition, unless the effect of this invention is impaired, the said radiation sensitive composition for nanoimprints may contain polymeric compounds other than the above. Hereinafter, each polymerizable compound will be described in detail.

[[A] polymerizable compound]
[A] The polymerizable compound is a polymerizable compound containing a sulfur atom.

  [A] Examples of the polymerizable group possessed by the polymerizable compound include (meth) acryloyl group, alkenyl group, cinnamoyl group, cinnamylideneacetyl group, benzalacetophenone group, styrylpyridine group, α-phenylmaleimide group, and phenylazide. Group, sulfonyl azide group, carbonyl azide group, diazo group, o-quinonediazide group, furylacryloyl group, coumarin group, pyrone group, anthracene group, benzophenone group, stilbene group, dithiocarbamate group, xanthate group, 1,2,3- A thiadiazole group, a cyclopropene group, an azadioxabicyclo group, etc. are mentioned. Of these, (meth) acryloyl groups are preferred.

  [A] The polymerizable compound is preferably a compound having an aromatic ring that enhances etching resistance by increasing the carbon content (decreasing the hydrogen content).

  By including such a [A] polymerizable compound, the nanoimprint radiation-sensitive composition is excellent in polymerizability, sufficiently satisfies basic characteristics such as curability, and is excellent in etching resistance.

  [A] As the polymerizable compound, a compound described in JP 2010-519369 is preferable as a compound having a (meth) acryloyl group and an aromatic ring. Specifically, the compound represented by the above formula (1) is more preferable.

The formula (1), ^{R A} and ^{R B} are each independently a hydrogen atom or a methyl group. R ¹ and R ² are each independently an alkanediyl group having 1 to 6 carbon atoms. X ¹ and X ² are each independently —S— or —O—. Y _{is, -S -, - SO 2 -} , - CO-, an alkanediyl group or an aralkylene group having 7 to 12 carbon atoms having 1 to 12 carbon atoms. However, you may have an oxygen atom or a sulfur atom between carbon-carbon of the alkylene chain of this alkanediyl group and aralkylene group. In addition, at least one of X ¹ , X ² and Y is a group containing a sulfur atom. Ar ¹ and Ar ² are each independently an arylene group having 6 to 30 carbon atoms or an aralkylene group having 7 to 30 carbon atoms. Some or all of the hydrogen atoms of the arylene group and aralkylene group may be substituted with a substituent that does not contain a fluorine atom. m and n are each independently an integer of 1 to 5. p is an integer of 0-10. When m is 2 or more, the plurality of R ¹ and X ¹ may be the same or different. When n is 2 or more, the plurality of R ² and X ² may be the same or different. When p is 2 or more, the plurality of Y and Ar ² may be the same or different.

The alkanediyl group having 1 to 6 carbon atoms represented by R ¹ and R ^2, for example, methylene group, ethylene group, propane-diyl group, etc. butanediyl group. Of these, an ethylene group is preferred.

  Examples of the alkanediyl group having 1 to 12 carbon atoms represented by Y include a methylene group, an ethylene group, a propanediyl group, a butanediyl group, an octanediyl group, a decanediyl group, and a dodecanediyl group.

  Examples of the aralkylene group having 7 to 12 carbon atoms represented by Y include a benzylidene group and a cinnamylidene group.

Examples of the arylene group having 6 to 30 carbon atoms represented by Ar ¹ and Ar ² include a phenylene group, a tolylene group, and a naphthylene group. Of these, a phenylene group is preferred.

Examples of the aralkylene group having 7 to 30 carbon atoms represented by Ar ¹ and Ar ² include a benzylidene group and a cinnamylidene group.

  Examples of the [A] polymerizable compound represented by the above formula (1) include compounds represented by the following formula (1-1).

  The [A] polymerizable compound represented by the above formula (1-1) can be synthesized by a known method.

  The amount of the polymerizable compound [A] used in the radiation-sensitive composition for nanoimprint is preferably 1% by mass to 90% by mass, more preferably 2% by mass to 50% by mass, and more preferably 5% by mass to 30% by mass. % Or less is more preferable. [A] If the usage-amount of a polymeric compound is less than 1 mass%, there exists a possibility that the etching tolerance of the said radiation sensitive composition for nanoimprint may become inadequate. On the other hand, when it exceeds 90 mass%, there exists a possibility that the solubility of the [A] polymeric compound in the said radiation sensitive composition for nanoimprint may become inadequate. In addition, [A] polymeric compound may be used independently and may use 2 or more types together.

[[B] polymerizable compound]
[B] The polymerizable compound is a polymerizable compound containing no sulfur atom.

  [B] The polymerizable compound is at least one compound selected from the group consisting of a compound represented by the above formula (2) and a compound represented by the above formula (3). By including such a [B] compound, the nanoimprint radiation-sensitive composition is excellent in polymerizability, sufficiently satisfies basic characteristics such as curability, and is excellent in etching resistance.

In the above formula (2), R ³ is a hydrogen atom or an s-valent organic group. s is 1 or 2. R ^C is a hydrogen atom or a methyl group. t is 0 or 1. However, when s is 2, two R ^C and t may be the same or different.

Examples of the s-valent organic group represented by R ³ include hydrocarbon groups having 1 to 20 carbon atoms.

  Examples of the hydrocarbon group having 1 to 20 carbon atoms include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic group having 3 to 20 carbon atoms, and an aromatic hydrocarbon group having 6 to 20 carbon atoms. Is mentioned. Here, the aromatic hydrocarbon group means a hydrocarbon group containing an aromatic ring.

  Examples of the chain hydrocarbon group having 1 to 20 carbon atoms include a group in which s hydrogen atoms are removed from an alkane having 1 to 20 carbon atoms. Examples of the alkane having 1 to 20 carbon atoms include methane, ethane, propane, butane, pentane, hexane, decane, and dodecane.

  Examples of the alicyclic group having 3 to 20 carbon atoms include a group in which s hydrogen atoms are removed from a cycloalkane having 3 to 20 carbon atoms. Examples of the cycloalkane having 3 to 20 carbon atoms include cyclopropane, cyclobutane, cyclopentane, cyclohexane, norbornane, adamantane and the like.

  Examples of the aromatic hydrocarbon group having 6 to 20 carbon atoms include aromatic hydrocarbons such as benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, pyrene, picene, toluene, xylene, ethylbenzene, mesitylene, cumene, and fluorene. And a group obtained by removing s hydrogen atoms from the group.

  The t is preferably 1.

  Examples of the compound represented by the above formula (2) include compounds represented by the following formulas (2-1) to (2-8).

  In the above formulas (2-4) and (2-5), t has the same meaning as the above formula (2).

  Among these, the compound represented by the above formula (2-1) is preferable.

  Commercially available products can be used as the compound represented by the above formula (2), for example, Biscote # 160 (manufactured by Osaka Organic Chemical Industry), Ogsol EA-F5003, Ogsol EA-F5503 (above, manufactured by Osaka Gas Chemical). Etc.

  The amount of the polymerizable compound [B] represented by the above formula (2) in the radiation-sensitive composition for nanoimprint is 10% by mass or more and 90% by mass or less, and 20% by mass or more and 70% by mass or less. preferable. If the usage-amount of the [B] polymeric compound represented by the said Formula (2) is less than 10 mass%, there exists a possibility that the sclerosis | hardenability of the said radiation sensitive composition for nanoimprint may become inadequate. On the other hand, when it exceeds 70 mass%, there exists a possibility that the etching tolerance of the said radiation sensitive composition for nanoimprint may become inadequate. In addition, the [B] polymeric compound represented by the said Formula (2) may be used independently, and may use 2 or more types together.

In the above formula (3), R ⁴ is a chain hydrocarbon group or an alicyclic hydrocarbon group having 4 to 20 carbon atoms. Part or all of the hydrogen atoms of the chain hydrocarbon group and alicyclic hydrocarbon group may be substituted with a substituent not containing a fluorine atom. R ^D and R ^E are each independently a hydrogen atom or a methyl group.

Examples of the chain hydrocarbon group having 4 to 20 carbon atoms represented by R ⁴ include a linear or branched alkylene group having 4 to 20 carbon atoms.

  Examples of the alkylene group include a butanediyl group, a pentanediyl group, a hexanediyl group, and an octanediyl group.

Examples of the alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ⁴ include two hydrogen atoms from cyclobutane, cyclopentane, dicyclohexane, tricyclodecane, tetracyclododecane, norbornane, adamantane and the like. Excluded groups are mentioned.

  Examples of the compound represented by the formula (3) include compounds represented by the following formulas (3-1) to (3-4).

  Among these, the compound represented by the above formula (3-1) is preferable.

  Examples of commercially available compounds represented by the above formula (3) include NK ester A-DCP (manufactured by Shin-Nakamura Chemical Co., Ltd.).

  The content of the polymerizable compound [B] represented by the above formula (3) in the radiation-sensitive composition for nanoimprint is preferably 10 to 80% by mass, and more preferably 15 to 50% by mass. preferable. When the content exceeds 80% by mass, the radiation-sensitive composition for nanoimprint may have a reduced etching resistance. On the other hand, if it is less than 10% by mass, the pattern forming layer may be insufficiently cured.

  The amount of the [B] polymerizable compound used in the radiation-sensitive composition for nanoimprinting is 50% by mass to 98% by mass, and preferably 60% by mass to 98% by mass. [B] If the usage-amount of a polymeric compound is less than 50 mass%, there exists a possibility that the sclerosis | hardenability of the said radiation sensitive composition for nanoimprint may become inadequate. On the other hand, when it exceeds 98 mass%, there exists a possibility that the etching tolerance of the said radiation sensitive composition for nanoimprint may become inadequate. In addition, [B] polymeric compound may be used independently and may use 2 or more types together.

[Polymerizable compound containing fluorine atom]
The said radiation sensitive composition for nanoimprint can improve mold release property by containing the polymeric compound containing the said fluorine atom.

  Examples of the polymerizable compound containing a fluorine atom include an α-fluoroacrylate compound, an α-trifluoromethyl acrylate compound, a β-fluoroacrylate compound, a β-trifluoromethyl acrylate compound, an α, β-fluoroacrylate compound, and an α, β. A trifluoromethyl acrylate compound, a compound in which hydrogen at one or more vinyl sites is substituted with fluorine or a trifluoromethyl group, and the like;

  The side chain of an alicyclic olefin compound such as norbornene is a fluorine or fluoroalkyl group or its derivative, the ester compound of a fluoroalkyl group of acrylic acid or methacrylic acid or its derivative, one or more olefin side chains ( A portion not containing a double bond) is a fluorine or fluoroalkyl group or a derivative thereof;

  Fluoroalkyl groups such as α-fluoroacrylic acid, β-fluoroacrylic acid, α, β-fluoroacrylic acid, α-trifluoromethylacrylic acid, β-trifluoromethylacrylic acid, α, β-trifluoromethylacrylic acid, etc. Or an ester compound thereof, or a compound in which the side chain of a compound in which hydrogen at one or more vinyl sites is substituted with fluorine or a trifluoromethyl group is substituted with a fluorine or fluoroalkyl group or a derivative thereof, and one or more fats Examples include those in which hydrogen bonded to a double bond of a cyclic olefin compound is substituted with a fluorine atom or a trifluoromethyl group and the side chain is a fluoroalkyl group or a derivative thereof. In addition, an alicyclic olefin compound here shows the compound in which a part of ring is a double bond.

  Specific examples of the polymerizable compound containing a fluorine atom include trifluoromethyl (meth) acrylic acid ester, 2,2,2-trifluoroethyl (meth) acrylic acid ester, and perfluoroethyl (meth) acrylic. Acid ester, perfluoro n-propyl (meth) acrylic acid ester, perfluoro i-propyl (meth) acrylic acid ester, perfluoro n-butyl (meth) acrylic acid ester, perfluoro i-butyl (meth) acrylic acid ester , Perfluoro t-butyl (meth) acrylate, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylate, 1- (2,2,3,3, 4,4,5,5-octafluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (Meth) acrylic acid ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, 1- (3,3,4,4,5,5,6,6, 7,7,8,8,9,9,10,10,10-heptadecafluorodecyl) (meth) acrylic acid ester, 1- (5-trifluoromethyl-3,3,4,4,5,6) , 6,6-octafluorohexyl) (meth) acrylic acid ester and the like.

  As content rate of the polymeric compound containing the fluorine atom in the said radiation sensitive composition for nanoimprints, they are 5 mass% or more and 50 mass% or less, and 10 mass% or more and 30 mass% or less are preferable. If the content of the polymerizable compound containing a fluorine atom is less than 5% by mass, the releasability of the nanoimprint radiation-sensitive composition may not be sufficiently obtained. On the other hand, when it exceeds 50 mass%, there exists a possibility that the etching tolerance of the said radiation sensitive composition for nanoimprint may become inadequate. In addition, the polymeric compound containing a fluorine atom may be used independently and may use 2 or more types together.

  As long as the effect of this invention is not impaired, the said radiation sensitive composition for nanoimprints does not impair the effect of this invention other than the polymerizable compound containing [A] polymeric compound, [B] polymeric compound, and a fluorine atom as a polymeric compound. A polymerizable compound can be contained.

<Non-polymerizable compound>
The radiation-sensitive composition for nanoimprint preferably further contains a non-polymerizable compound having no polymerizable group, and the non-polymerizable compound may be a compound containing a fluorine atom. Moreover, the said radiation sensitive composition for nanoimprint may contain the nonpolymerizable compound containing a sulfur atom. Further, other non-polymerizable compounds can be contained as long as the effects of the present invention are not impaired.

[Non-polymerizable compound containing fluorine atom]
Examples of the non-polymerizable compound containing a fluorine atom include a polymer having a fluorine atom (hereinafter also referred to as “[C] polymer”), a fluorine-based surfactant, etc. Among these, [C] heavy The radiation-sensitive composition for nanoimprinting can improve releasability by containing a non-polymerizable compound containing a fluorine atom.Hereinafter, each component will be described in detail.

([C] polymer)
[C] The polymer is at least one structural unit selected from the group consisting of the structural unit (c1) represented by the following formula (4) and the structural unit (c2) represented by the following formula (5). It is preferable to have. Moreover, unless the effect of this invention is impaired, you may have "other structural units" other than a structural unit (c1) and a structural unit (c2). Hereinafter, each structural unit will be described in detail.

In the formula (4), R ⁵ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁶ is a linear or branched alkyl group having 1 to 6 carbon atoms having a fluorine atom, or an alicyclic group having 4 to 20 carbon atoms having a fluorine atom. However, one part or all part of the hydrogen atom which the said alkyl group and alicyclic group have may be substituted by the substituent.
In formula (5), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁸ is a (k + 1) -valent linking group. R ^f is a divalent linking group having a fluorine atom. R ⁹ is a hydrogen atom or a monovalent organic group. k is an integer of 1 to 3. However, when k is 2 or 3, the plurality of R ^f and R ⁹ may be the same or different.

(Structural unit (c1))
The structural unit (c1) is a structural unit represented by the above formula (4).

In the formula (4), as the linear or branched alkyl group having 1 to 6 carbon atoms represented by R ^6, for example a methyl group, an ethyl group, a propyl group, a butyl group.

Examples of the alicyclic group having 4 to 20 carbon atoms represented by R ⁶ include a cyclopentyl group, a cyclopentylpropyl group, a cyclohexyl group, a cyclohexylmethyl group, a cycloheptyl group, a cyclooctyl group, and a cyclooctylmethyl group. It is done.

  Examples of the monomer that gives the structural unit (c1) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, perfluoro n-propyl ( (Meth) acrylate, perfluoro i-propyl (meth) acrylate, perfluoro n-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, perfluoro t-butyl (meth) acrylate, perfluorocyclohexyl (meth) Acrylate, 2- (1,1,1,3,3,3-hexafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoro) pentyl ( (Meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoro) hex (Meth) acrylate, perfluorocyclohexylmethyl (meth) acrylate, 1- (2,2,3,3,3-pentafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4, 4,4-Heptafluoro) penta (meth) acrylate, 1- (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- Heptadecafluoro) decyl (meth) acrylate, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6-octafluoro) hexyl (meth) acrylate and the like.

  Examples of the structural unit (c1) include structural units represented by the following formulas (4-1) and (4-2).

In the above formula (4-1) and (4-2), ^{R 5} has the same meaning as the above formula (4).

  In the [C] polymer, the content of the structural unit (c1) is preferably 10 mol% to 70 mol%, and 20 mol% to 50 mol% with respect to all the structural units constituting the [C] polymer. More preferred. The [C] polymer may have one or more structural units (c1).

(Structural unit (c2))
The structural unit (c2) is a structural unit represented by the above formula (5).

In the above formula (5), the (k + 1) -valent linking group represented by R ⁷ is, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms or an alicyclic hydrocarbon having 3 to 30 carbon atoms. A group, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or one or more groups selected from the group consisting of these groups and an oxygen atom, a sulfur atom, an ether group, an ester group, a carbonyl group, an imino group, and an amide group And a combination of these. The (k + 1) -valent linking group may have a substituent.

  Examples of the linear or branched hydrocarbon group having 1 to 30 carbon atoms include hydrocarbon groups such as methane, ethane, propane, butane, pentane, hexane, heptane, decane, icosane and triacontane (k + 1). And groups in which one hydrogen atom is removed.

Examples of the alicyclic group having 3 to 30 carbon atoms include monocyclic saturated hydrocarbons such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, methylcyclohexane, and ethylcyclohexane;
Monocyclic unsaturated hydrocarbons such as cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene;
Bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [3.3.1.1 ^3,7 ] decane, Tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] polycyclic saturated hydrocarbons such as dodecane and adamantane;
Bicyclo [2.2.1] heptene, bicyclo [2.2.2] octene, tricyclo [5.2.1.0 ^2,6 ] decene, tricyclo [3.3.1.1 ^3,7 ] decene, Tetracyclo [6.2.1.1 ^3,6 . And a group obtained by removing (k + 1) hydrogen atoms from a polycyclic hydrocarbon group such as 0 ^2,7 ] dodecene.

  Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include aromatic hydrocarbon groups such as benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, pyrene, picene, toluene, xylene, ethylbenzene, mesitylene, cumene ( and a group excluding k + 1) hydrogen atoms.

In the above formula (5), examples of the divalent linking group having a fluorine atom represented by R ^f include a C 1-20 divalent linear hydrocarbon group having a fluorine atom. Examples of R ^f include structures represented by the following formulas (R ^f -1) to (R ^f -6).

R ^f is preferably a structure represented by the above formula (R ^f -1) or (R ^f -2).

In the above formula (5), examples of the organic group represented by R ⁹ include a linear or branched hydrocarbon group having 1 to 30 carbon atoms, an alicyclic group having 3 to 30 carbon atoms, and 6 to 30 carbon atoms. Or a group in which these groups are combined with one or more groups selected from the group consisting of an oxygen atom, a sulfur atom, an ether group, an ester group, a carbonyl group, an imino group, and an amide group. It is done.

  Examples of the structural unit (c2) include structural units represented by the following formulas (5-1) and (5-2).

In said formula (5-1), R < ⁸ > is a C1-C20 bivalent linear, branched or cyclic saturated or unsaturated hydrocarbon group. R ⁷ , R ^f and R ⁹ have the same meaning as in the above formula (5).
In said formula (5-2), R < ^{7 >} , R <^f> , R < ⁹ > and k are synonymous with said formula (5). However, when k is 2 or more, the plurality of R ^f and R ⁹ may be the same or different.

  Examples of the structural unit represented by the above formula (5-1) and formula (5-2) include the following formula (5-1-1), formula (5-1-2), and formula (5-2-1). ).

In the above formulas (5-1-1), (5-1-2) and (5-2-1), R ⁷ has the same meaning as the above formula (5).

  Examples of the monomer that gives the structural unit (c2) include (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester and (meth) acrylic acid. (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy -5-pentyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, (meth) acrylic acid 2-{[5- ( 1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl} ester and the like.

  In the [C] polymer, the content of the structural unit (c2) is preferably 20% by mole to 80% by mole, and preferably 30% by mole to 70% by mole with respect to all the structural units constituting the [C] polymer. More preferred. In addition, the [C] polymer may have 1 type, or 2 or more types of structural units (c2).

(Other structural units)
[C] The polymer further includes, as “other structural units”, structural units having a lactone skeleton or a cyclic carbonate skeleton to enhance solubility in a developer, and structural units containing an alicyclic structure to enhance etching resistance. Etc. may have one or more.

  [C] As a content rate of a polymer, 20 mass% or less is preferable in the said radiation sensitive composition for nanoimprint, and 10 mass% or less is more preferable. [C] When the content rate of a polymer exceeds 20 mass%, there exists a possibility that the etching tolerance of the said radiation sensitive composition for nanoimprint may reduce.

([C] Polymer Synthesis Method)
[C] The polymer can be synthesized according to a conventional method such as radical polymerization. For example,
A method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction;
A method in which a solution containing a monomer and a solution containing a radical initiator are separately dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction;
A plurality of types of solutions containing each monomer and a solution containing a radical initiator are separately added to a reaction solvent or a solution containing a monomer and synthesized by a method such as a polymerization reaction. It is preferable. In addition, when the monomer solution is dropped and reacted with respect to the monomer solution, the monomer amount in the dropped monomer solution is 30 mol with respect to the total amount of monomers used for polymerization. % Or more is preferable, 50 mol% or more is more preferable, and 70 mol% or more is particularly preferable.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30 degreeC-180 degreeC, 40 degreeC-160 degreeC is preferable, and 50 degreeC-140 degreeC is more preferable. The dropping time varies depending on the reaction temperature, the type of initiator, the monomer to be reacted, etc., but is usually 30 minutes to 8 hours, preferably 45 minutes to 6 hours, and more preferably 1 hour to 5 hours. . Further, the total reaction time including the dropping time varies depending on the conditions similarly to the dropping time, but is usually 30 minutes to 8 hours, preferably 45 minutes to 7 hours, and more preferably 1 hour to 6 hours.

  Examples of the radical initiator used in the polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 -Cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile) and the like. These initiators can be used alone or in admixture of two or more.

The polymerization solvent is not limited as long as it is a solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, etc.) and can dissolve the monomer. Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. These solvents may be used alone or in combination of two or more.

  The resin obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after completion of the polymerization reaction, the target resin is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the resin can be recovered by removing low-molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

  [C] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is not particularly limited, but is preferably 1,000 or more and 100,000 or less, more preferably 2,000 or more and 50,000 or less. Preferably, it is 3,000 or more and 20,000 or less. By setting Mw within the above range, the radiation-sensitive composition for nanoimprinting has excellent etching resistance.

  In addition, the ratio (Mw / Mn) of Mw to polystyrene-converted number average molecular weight (Mn) by GPC of the [C] polymer is usually from 1 to 5, preferably from 1 to 3, preferably from 1 to 2. More preferred. By setting Mw / Mn in such a range, the radiation-sensitive composition for nanoimprinting has excellent etching resistance.

  In addition, Mw and Mn of this specification use GPC columns (Tosoh Corporation, G2000HXL 2 pieces, G3000HXL 1 piece, G4000HXL 1 piece), flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. The value measured by GPC using monodisperse polystyrene as a standard under conditions.

(Fluorosurfactant)
Examples of the fluorine-based surfactant include perfluoroalkyl polyoxyethylene ethanol, fluorinated alkyl ester, perfluoroalkylamine oxide, perfluoroalkyl EO adduct, fluorine-containing organosiloxane compound, and the like. Examples of commercially available fluorosurfactants include F-Top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F172, F173, F176, F189, R08, F-8151 (manufactured by DIC), Fluorard FC-430, FC-431, FC-4430 (manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-141, S-145, S-381, S-382, SC101, SC102, SC103, SC104, SC105, SC106 , Surfynol E1004, KH-10, KH-20, KH-30, KH-40 (Asahi Glass), Unidyne DS-401, DS-403, DS-451 (Daikin Industries), Troisol S-366 (Troy Chemical) Manufactured), KP341, X-70-092 X-70-093 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical) and the like.

[Non-polymerizable compound containing sulfur atom]
The said radiation sensitive composition for nanoimprint can contain the nonpolymerizable compound containing a sulfur atom. The radiation-sensitive composition for nanoimprinting can improve etching resistance by containing a non-polymerizable compound containing a sulfur atom. Examples of the non-polymerizable compound containing a sulfur atom include a polymer containing a sulfur atom and other compounds containing a sulfur atom and having no polymerizable group.

<[D] Polymerization initiator>
In the radiation-sensitive composition for nanoimprint, [D] the polymerization initiator is polymerized by a polymerizable compound such as [A] polymerizable compound, [B] polymerizable compound, and a polymerizable compound containing a fluorine atom upon exposure. The group is activated to induce a curing reaction of the radiation-sensitive composition for nanoimprinting.

  [D] As the polymerization initiator, for example, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2,2′-azobisisobutyronitrile, 2,2 ′ -Azobis- (2,4-dimethylvaleronitrile), 2,2'-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis- (2-methylbutyronitrile), Azo compounds such as 1,1′-azobis- (cyclohexane-1-carbonitrile), dimethyl-2,2′-azobis (2-methylpropionate); benzoyl peroxide, lauroyl peroxide, tert-butylperoxypivalate, Examples thereof include organic peroxides such as 1,1′-bis- (tert-butylperoxy) cyclohexane, hydrogen peroxide, and the like. Moreover, when using an organic peroxide as a [D] polymerization initiator, it is good also as a redox type [D] polymerization initiator combining a reducing agent.

  In addition to these polymerization initiators, for example, biimidazole compounds described in JP 2007-293306 A, oxime type radical generators, benzoin compounds, acetophenones described in JP 2008-89744 A, for example. Compounds, benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, xanthone compounds, phosphine compounds, triazine compounds, and diazo compounds and triazine compounds described in JP-A-2006-259680 Can do.

  The content of the [D] polymerization initiator in the radiation-sensitive composition for nanoimprint is preferably 1% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 20% by mass or less. More preferably, it is at least 10% by mass. When the content exceeds 30% by mass, the storage stability tends to deteriorate, for example, foreign matter is generated. On the other hand, if it is less than 1% by mass, the pattern forming layer may be insufficiently cured.

<Other optional components>
In addition to the polymerizable compound, non-polymerizable compound, and [D] polymerization initiator, the radiation-sensitive composition for nanoimprint is an organic solvent, a release agent, a silane coupling agent, an oxidation, unless the effects of the present invention are impaired. It may contain other optional components such as an inhibitor, an ultraviolet absorber, a light stabilizer, an anti-aging agent, a plasticizer, an adhesion promoter, an antioxidant, and a basic compound. Hereinafter, each component will be described in detail.

[Organic solvent]
The nanoimprint radiation-sensitive composition is preferably an organic solvent-free composition, but may contain an organic solvent as long as the effects of the present invention are not impaired. More specifically, the total amount of [A] polymerizable compound, [B] polymerizable compound such as polymerizable compound, [C] non-polymerizable compound such as polymer and [D] polymerization initiator is usually The organic solvent may be contained in an amount of 2,000% by mass or less, preferably 1,000% by mass or less.

  Examples of the organic solvent that the radiation-sensitive composition for nanoimprint may contain include, for example, alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, Glycol ethers such as ethylene glycol monoethyl ether; ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate; diethylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether, diethylene glycol mono Butylue Diethylene glycols such as ter; propylene glycol alkyl ether acetates such as propylene glycol methyl ether acetate and propylene glycol ethyl ether acetate; aromatic hydrocarbons such as toluene and xylene; acetone, methyl ethyl ketone, cyclohexanone, 4-hydroxy-4-methyl Ketones such as 2-pentanone and 2-heptanone; ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, Methyl 2-hydroxy-2-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3-ethoxypropion Esters such as ethyl, ethyl acetate, butyl acetate, methyl lactate, lactate esters such as ethyl lactate, etc .; N-methylformamide, N, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N, N -Dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, benzyl ethyl ether, dihexyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, sulphur Examples include high-boiling solvents such as diethyl acid, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, and phenyl cellosolve acetate. In addition, these may be used individually by 1 type and may use 2 or more types together.

[Release agent]
Examples of the release agent that the radiation-sensitive composition for nanoimprint may contain include, for example, silicone-based release agents, solid waxes such as polyethylene wax, amide wax, and tetrafluoroethylene powder, fluorine-based, phosphate ester-based Compounds and the like.

  Examples of the silicone release agent include release agents having an organopolysiloxane structure as a basic structure, such as unmodified or modified silicone oil, polysiloxane containing trimethylsiloxysilicic acid, and silicone acrylic resin.

  As a content rate of a mold release agent, it is preferable that it is 0.001-10 mass% with respect to 100 mass% of the said radiation sensitive composition for nanoimprints, and it is more preferable that it is 0.01-5 mass%. . If it is less than 0.01% by mass, the effect of containing a release agent may not be sufficient. On the other hand, if it exceeds 10 mass%, film peeling may occur during shape transfer.

[Silane coupling agent]
Examples of the silane coupling agent that may be contained in the nanoimprint radiation-sensitive composition include vinyl silanes such as vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, and vinyltrimethoxysilane; γ -Acrylic silane such as methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane; β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycid Epoxy silanes such as xylpropylmethyldiethoxysilane; N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltri Meto Examples include aminosilanes such as xysilane and N-phenyl-γ-aminopropyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, and γ-chloropropylmethyldiethoxysilane.

  As a content rate of a silane coupling agent, it is preferable that it is 10 mass% or less with respect to 100 mass% of radiation sensitive compositions for nanoimprint. When it exceeds 10 mass%, the stability and film formability of the radiation-sensitive composition for nanoimprinting may be inferior.

[Ultraviolet absorber]
Examples of commercially available ultraviolet absorbers that the nanoimprint radiation-sensitive composition may contain include, for example, Tinuvin P, 234, 320, 326, 327, 328, 213 (above, manufactured by Ciba Geigy, Japan), Sumisorb 110, 130, 140, 220, 250, 300, 320, 340, 350, 400 (above, manufactured by Sumitomo Chemical Co., Ltd.). As a content rate of a ultraviolet absorber, it is preferable that it is 0.01-10 mass% with respect to 100 mass% of the said radiation sensitive composition for nanoimprints.

[Light stabilizer]
Examples of commercially available light stabilizers that may be contained in the nanoimprint radiation-sensitive composition include, for example, Tinuvin 292, 144, and 622LD (manufactured by Ciba Geigy, Japan), Sanol LS-770, 765, and 765 292, 2626, 1114, 744 (Sankyo Chemical Industries, Ltd.). The content ratio of the light stabilizer is preferably 0.01 to 10% by mass with respect to 100% by mass of the radiation-sensitive composition for nanoimprint.

[Anti-aging agent]
Examples of commercially available anti-aging agents that may be contained in the radiation-sensitive composition for nanoimprint include, for example, Antigene W, S, P, 3C, 6C, RD-G, FR, and AW. (Above, manufactured by Sumitomo Chemical Co., Ltd.) and the like. As a content rate of an anti-aging agent, it is preferable that it is 0.01-10 mass% with respect to 100 mass% of radiation sensitive compositions for nanoimprint.

[Plasticizer]
Examples of the plasticizer that may be contained in the radiation-sensitive composition for nanoimprint include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate , Triacetyl glycerin, dimethyl adipate, diethyl adipate, di (n-butyl) adipate, dimethyl suberate, diethyl suberate, di (n-butyl) suberate and the like. As a content rate of a plasticizer, it is preferable that it is 30 mass% or less with respect to 100 mass% of the said radiation sensitive composition for nanoimprints, It is more preferable that it is 20 mass% or less, It is 10 mass% or less. More preferably. In addition, in order to acquire the effect of a plasticizer, it is preferable that it is 0.1 mass% or more.

[Adhesion promoter]
Examples of the adhesion promoter that may be contained in the radiation-sensitive composition for nanoimprint include benzimidazoles and polybenzimidazoles, lower hydroxyalkyl-substituted pyridine derivatives, nitrogen-containing heterocyclic compounds, urea, thiourea, and organic phosphorus. Compound, 8-oxyquinoline, 4-hydroxypteridine, 1,10-phenanthroline, 2,2′-bipyridine derivative, benzotriazoles, organic phosphorus compound, phenylenediamine compound, 2-amino-1-phenylethanol, N-phenyl Examples include ethanolamine, N-ethyldiethanolamine, N-ethyldiethanolamine, N-ethylethanolamine, N-ethylethanolamine derivatives, and benzothiazole derivatives. The content ratio of the adhesion promoter is preferably 20% by mass or less, more preferably 10% by mass or less, and more preferably 5% by mass or less with respect to 100% by mass of the radiation-sensitive composition for nanoimprint. More preferably it is. In addition, in order to acquire the effect of an adhesion promoter, it is preferable that it is 0.1 mass% or more.

[Antioxidant]
The antioxidant suppresses fading caused by light irradiation and fading caused by various oxidizing gases such as ozone, active oxygen, NO _x , and SO _x (x represents an integer). Examples of the antioxidant that may be contained in the radiation-sensitive composition for nanoimprint include, for example, hydrazides, hindered amine-based antioxidants, nitrogen-containing heterocyclic mercapto-based compounds, thioether-based antioxidants, and hindered phenol-based oxidations. Examples thereof include inhibitors, ascorbic acids, zinc sulfate, thiocyanates, thiourea derivatives, saccharides, nitrites, sulfites, thiosulfates, hydroxylamine derivatives, and the like.

  Examples of commercially available antioxidants include Irganox 1010, 1035, 1076, 1222 (manufactured by Ciba Geigy, Japan), Antigene P, 3C, FR, Sumilizer S (manufactured by Sumitomo Chemical Co., Ltd.), etc. Is mentioned. It is preferable that the content rate of antioxidant is 0.01-10 mass% with respect to 100 mass% of the said radiation sensitive composition for nanoimprints.

[Basic compounds]
Examples of the basic compound that may be contained in the radiation-sensitive composition for nanoimprint include amines; nitrogen-containing heterocyclic compounds such as quinoline and quinolidine; basic alkali metal compounds; basic alkaline earth metal compounds. Can be mentioned. Of these, amine is preferred from the viewpoint of compatibility with the photopolymerizable monomer. Examples of the amine include octylamine, naphthylamine, xylenediamine, dibenzylamine, diphenylamine, dibutylamine, dioctylamine, dimethylaniline, quinuclidine, tributylamine, trioctylamine, tetramethylethylenediamine, tetramethyl-1,6- Hexamethylenediamine, hexamethylenetetramine, triethanolamine and the like can be mentioned.

  In addition to these components, the radiation-sensitive composition for nanoimprints, in addition to these components, is a colorant, inorganic particles, elastomer particles, photoacid proliferator, photobase generator, flow regulator, antifoaming agent, A dispersing agent etc. can be contained.

<Method for preparing the radiation-sensitive composition for nanoimprint>
The nanoimprint radiation-sensitive composition can be prepared by mixing the components described above. The mixing and dissolution of the radiation-sensitive composition for nanoimprint is usually performed in the range of 0 ° C to 100 ° C. Moreover, after mixing each said component, it is preferable to filter with a filter with the hole diameter of 0.003 micrometer-5.0 micrometers, for example. Filtration may be performed in multiple stages or repeated many times. Moreover, the filtered liquid can be refiltered. Examples of the material of the filter used for filtration include polyethylene resin, polypropylene resin, fluorine resin, and nylon resin.

  The viscosity at 25 ° C. of the radiation-sensitive composition for nanoimprint is usually 50 mPa · s or less, preferably 40 mPa · s or less, and more preferably 30 mPa · s or less. If the viscosity at 25 ° C. exceeds 50 mPa · s, the pattern may not be accurately transferred when the mold is pressed against the pattern forming layer made of the radiation-sensitive composition for nanoimprinting. The lower limit of the viscosity is usually 0.1 mPa · s.

<Pattern formation method>
The pattern forming method of the present invention comprises a step (1) of forming a coating film on a substrate using the radiation-sensitive composition for nanoimprint (hereinafter also referred to as “coating layer forming step”), and a fine surface. A step (2) of pressing a mold having a concavo-convex pattern against the coating film (hereinafter also referred to as a “pressing step”), and a step of forming a pattern forming layer by exposing the coating film in a state of pressing the mold (3) (Hereinafter also referred to as “exposure step”), step (4) for peeling the mold from the pattern forming layer (hereinafter also referred to as “peeling step”), step for etching the pattern forming layer (5) (Hereinafter also referred to as “etching step”). Hereinafter, each process is explained in full detail.

[Step (1)]
A coating-film formation process is a process of forming a coating film using the said radiation sensitive composition for nanoimprints on a base material. Drawing 1 is a mimetic diagram showing an example of the state after forming a coat on a substrate. As shown in FIG. 1, the coating film forming process is a process of forming a coating film 2 on the substrate 1.

  As a base material, a silicon wafer is usually used, but it is also known as a substrate for semiconductor devices such as aluminum, titanium-tungsten alloy, aluminum-silicon alloy, aluminum-copper-silicon alloy, silicon oxide, and silicon nitride. It can be used by arbitrarily selecting from the existing ones.

  The component which comprises a coating film is the said radiation sensitive composition for nanoimprints. Moreover, a hardening accelerator etc. can be contained in the coating film other than the said radiation sensitive composition for nanoimprints. Examples of the curing accelerator include a radiation-sensitive curing accelerator and a thermosetting accelerator. Among these, a radiation sensitive curing accelerator is preferable. A radiation sensitive hardening accelerator can be suitably selected with the structural unit which comprises the radiation sensitive composition for nanoimprints. Specific examples include photoacid generators, photobase generators, and photosensitizers. In addition, a radiation sensitive hardening accelerator may be used individually by 1 type, and may use 2 or more types together.

  The nanoimprint radiation-sensitive composition includes, for example, an inkjet method, a dip coating method, an air knife coating method, a curtain coating method, a wire barcode method, a gravure coating method, an extrusion coating method, a spin coating method, a slit scanning method, and the like. Thus, it is possible to form a pattern forming layer by applying on the substrate. In addition, although the film thickness of a pattern formation layer changes with uses, it is 0.01-5.0 micrometers, for example.

[Step (2)]
The pressure contact process is a process in which a fine mold having a concavo-convex pattern of, for example, a nanometer order is pressed on the coating film. Here, the concave / convex pattern of the mold is a reverse pattern of a desired pattern. FIG. 2 is a schematic diagram showing an example of a state where the mold is pressed against a coating film. As shown in FIG. 2, an uneven pattern of the mold 3 is formed in the coating film 2 by pressing the mold 3 against the coating film 2 formed in the step (1).

  The pressure when pressing the mold is usually 0.1 MPa to 100 MPa, preferably 0.1 MPa to 50 MPa, more preferably 0.1 MPa to 30 MPa, and 0.1 MPa to 20 MPa. More preferably. Further, the time for pressure contact is usually 1 second to 600 seconds, preferably 1 second to 300 seconds, more preferably 1 second to 180 seconds, and further preferably 1 second to 120 seconds. preferable.

  The mold needs to be made of a light transmissive material. Examples of the light transmissive material include a light transparent resin such as glass, quartz, PMMA, and polycarbonate resin; a transparent metal vapor deposited film; a flexible film such as polydimethylsiloxane; a photocured film; and a metal film.

  In addition, it is preferable that the mold used in this step is subjected to a hydrophobic treatment in advance. Examples of the hydrophobizing treatment include a treatment such as applying a release agent to the surface of the mold having a concavo-convex pattern on the surface.

  Examples of the release agent include silicon release agents, fluorine release agents, polyethylene release agents, polypropylene release agents, paraffin release agents, montan release agents, carnauba release agents. Etc. In addition, a mold release agent may be used individually by 1 type, and may use 2 or more types together. Of these, silicon-based release agents are preferred. Examples of the silicon release agent include polydimethylsiloxane, acrylic silicone graft polymer, acrylic siloxane, and arylsiloxane.

[Step (3)]
An exposure process is a process of exposing a coating film, pressing a mold. FIG. 3 is a schematic diagram showing an example of a state in which the coating film is exposed while the mold is pressed. As shown in FIG. 3, by exposing the coating film 2, radicals are generated from the [D] polymerization initiator contained in the radiation-sensitive composition for nanoimprinting. Thereby, the coating film which consists of the said radiation sensitive composition for nanoimprint hardens | cures in the state which the uneven | corrugated pattern of the mold 3 was transcribe | transferred, and forms the pattern formation layer 5 in FIG. By transferring the concavo-convex pattern, it can be used as, for example, a film for an interlayer insulating film of a semiconductor element such as LSI, system LSI, DRAM, SDRAM, RDRAM, or D-RDRAM, a resist film when manufacturing the semiconductor element, and the like. .

  Examples of the exposure source include radiation (ArF excimer laser (wavelength: 193 nm) or KrF excimer laser (wavelength: 248 nm) such as UV light, visible light, ultraviolet light, far ultraviolet light, X-ray, and electron beam. ) Can be used. Further, the exposure may be performed on the entire surface of the pattern forming layer, or may be performed only on a partial region.

  Further, when the pattern forming layer has thermosetting properties, heat curing may be further performed. When thermosetting is performed, the heating atmosphere and the heating temperature are not particularly limited. For example, heating can be performed at 40 to 200 ° C. under an inert atmosphere or under reduced pressure. Heating can be performed using a hot plate, an oven, a furnace, or the like.

[Step (4)]
The peeling process is a process of peeling the mold 3 from the pattern forming layer 5. FIG. 4 is a schematic diagram illustrating an example of a state after the mold is peeled from the pattern forming layer. The peeling process may be performed in any manner, and various conditions for peeling are not particularly limited. That is, for example, the base material 1 may be fixed and the mold may be moved away from the base material 1 for peeling, or the mold may be fixed and the base material 1 moved away from the mold for peeling. Well, both of them may be peeled by pulling in the opposite direction.

[Step (5)]
The etching step is a step of removing the remaining concave portion of the pattern forming layer by etching. FIG. 5 is a schematic diagram illustrating an example of a state after etching. As shown in FIG. 5, by performing an etching process, an unnecessary portion can be removed from the pattern shape of the pattern forming layer, and a desired resist pattern 10 can be formed. In the pattern formation method, since the radiation-sensitive composition for nanoimprinting excellent in etching resistance is used, a pattern excellent in pattern shape can be formed.

It does not specifically limit as an etching method, It can form by performing a conventionally well-known method, for example, dry etching. A conventionally known dry etching apparatus can be used for the dry etching. The source gas at the time of dry etching is appropriately selected according to the elemental composition of the film to be etched, but includes an oxygen atom gas such as O ₂ , CO, CO ₂ , an inert gas such as He, N ₂ , Ar, A chlorine-based gas such as Cl ₂ or BCl ₃ , a gas of H ₂ or NH ₃ , or the like can be used. In addition, these gases can also be mixed and used.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. The ¹³ C-NMR analysis was measured using JNM-EX270 (manufactured by JEOL).

<Synthesis of [C] polymer>
A monomer solution was prepared by dissolving 40 g (100 mol%) of the following compound (M-1) and 2.82 g of an initiator (methyl 2,2′-azobis- (2-methylpropionate)) in 40 g of methyl ethyl ketone. . 40 g of methyl ethyl ketone was added to a 300 ml three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. The flask was heated to 80 ° C. while stirring with a magnetic stirrer. The monomer solution was added to the dropping funnel and dropped over 3 hours. After completion of the dropwise addition, the reaction was continued for another 3 hours and cooled to 30 ° C. or lower to obtain a polymer solution. The obtained polymer solution was adjusted by adding methyl ethyl ketone to 120 g, transferred to a separatory funnel together with 40 g of methanol and 240 g of n-hexane, and after stirring sufficiently, the lower layer was separated. In the lower layer, 30 g of methanol and 160 g of n-hexane were mixed and transferred to a separatory funnel, and the lower layer was separated. The solvent in the lower layer obtained here was distilled off, and the resulting white powder was vacuum dried at 50 ° C. for 17 hours to obtain 30.5 g (yield 76%) of polymer (C-1). Mw of (C-1) was 11,800, and Mw / Mn was 2.3.

<Preparation of radiation-sensitive composition for nanoimprint>
[Example 1]
[A] (A-1) 5.0% by mass as a polymerizable compound, (B-1) 37.0% by mass, (B-2) 49.0% by mass as [B] polymerizable compound, [C] A radiation-sensitive composition for nanoimprinting was prepared by mixing 2.0% by mass of (C-1) as a polymer and 7.0% by mass of (D-1) as a [D] polymerization initiator.

[Examples 2 to 5 and Comparative Example 1]
A radiation-sensitive composition for nanoimprinting was prepared in the same manner as in Example 1 except that each type and amount of components shown in Table 1 were used.

  [A] polymerizable compound, [B] polymerizable compound, and [D] polymerization initiator used for preparation of each Example and Comparative Example are as follows.

<[A] polymerizable compound>
(A-1): A polymerizable compound represented by the following formula.

＜［Ｂ］重合性化合物＞
（Ｂ−１）：下記式で表されるトリシクロデカンジメタノールジアクリレート（新中村化学工業製）

<[B] Polymerizable compound>
(B-1): Tricyclodecane dimethanol diacrylate represented by the following formula (manufactured by Shin-Nakamura Chemical Co., Ltd.)

(B-2): Benzyl acrylate represented by the following formula (manufactured by Osaka Organic Chemical Industry)

＜［Ｄ］重合開始剤＞
（Ｄ−１）：下記式で表される２−メチル−１−［４−（メチルチオ）フェニル］−２−モルフォリノプロパン−１−オン

<[D] Polymerization initiator>
(D-1): 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one represented by the following formula

<Evaluation>
Each of the radiation-sensitive compositions for nanoimprint prepared as described above was evaluated as follows. The results are shown in Table 1.

[Viscosity evaluation]
The viscosity of each radiation-sensitive composition for nanoimprint prepared as described above was measured at 25 ° C. using an E-type viscometer (manufactured by Tokimec).

[Etching rate evaluation]
The glass slide used for sample preparation was subjected to UV ozone cleaning with UV SURFACE PROCESSOR PM9011-B (manufactured by Sen Special Light Source) and mold release treatment with HD-1100Z (manufactured by Daikin Chemicals). 2 μL of each nanoimprint radiation-sensitive composition was applied onto a silicon wafer using a micropipette, the glass slide was brought into close contact with the top, and 0.3 MPa using a simple imprint apparatus (EUN-4200, manufactured by Engineering System). Then, the radiation-sensitive composition for nanoimprinting was cured with a UV irradiation amount of about 300 mJ / cm ² (2.57 mW / cm ² × 120 seconds). After peeling the slide glass, the obtained radiation-sensitive composition film was placed in a chamber of a simple ashing device (E1113-C23, manufactured by Shinko Seiki Co., Ltd.) under the conditions of CF ₄ single gas 50 mL / min and output 200 mW. Etching was performed for 10 minutes. At that time, the film thickness of the radiation-sensitive composition film before and after etching was measured using a stylus type film thickness measuring device (Alpha-Step 500, manufactured by KLA Tencor). Each etching rate (nm / min) is shown in Table 1.

  As shown in Table 1, it was found that the radiation-sensitive compositions for nanoimprints of Examples 1 to 5 had a lower etching rate and excellent etching resistance as compared with the radiation-sensitive composition for nanoimprints of Comparative Example 1. .

[Pattern formation]
Using a coater / developer (CLEAN TRACK ACT8, manufactured by Tokyo Electron), an organic underlayer film (NFC CT08, manufactured by JSR) having a film thickness of 300 nm was formed on the surface of an 8-inch silicon wafer. Next, after forming an inorganic intermediate film (NFC SOG08, manufactured by JSR) having a film thickness of 45 nm, it was divided into four to obtain experimental substrates. Thereafter, about 50 μL of the curable composition for nanoimprint prepared in Example 1 was spotted on the center of the experimental substrate, and placed on the work stage of a simple imprint apparatus (EUN-4200, manufactured by Engineering System). On the other hand, a quartz mold (NIM-PH350, manufactured by NTT-ATN) in which a release agent (HD-1100Z, manufactured by Daikin Chemicals Sales) is applied in a predetermined method in advance, and silicone rubber (thickness 0.2 mm) are bonded to each other. As a result, it was attached to a quartz exposure head of a simple imprint apparatus. Next, after setting the pressure of the simple imprint apparatus to 0.2 MPa, the exposure head is lowered, the mold and the experimental substrate are brought into close contact with each other via the nanoimprint radiation-sensitive composition, and then UV exposure is performed for 15 seconds. did. The exposure stage was raised after 15 seconds, and the mold was peeled off from the cured pattern forming layer to form a pattern. When the mold was peeled off, there was no residue on the mold and there was no pattern collapse. The nanoimprint radiation-sensitive composition was excellent in releasability.

  The radiation-sensitive composition for nanoimprinting of the present invention is excellent in etching resistance and can be suitably used for nanoimprinting used for improving the degree of integration and recording density of circuits such as semiconductor elements.

1: Substrate 2: Coating film 3: Mold 4: Light 5: Pattern forming layer 10: Resist pattern

Claims (5)

Containing a polymerizable compound containing a sulfur atom, and a radiation-sensitive polymerization initiator ,
A radiation-sensitive composition for nanoimprinting , wherein the polymerizable compound containing a sulfur atom is a compound represented by the following formula (1) .

(In Formula (1), R ^A and R ^B are each independently a hydrogen atom or a methyl group. R ¹ and R ² are each independently an alkanediyl group having 1 to 6 carbon atoms. X ¹ and X ² are each independently —S— or —O—, Y is —S—, —SO ₂ —, —CO—, an alkanediyl group having 1 to 12 carbon atoms or carbon. An aralkylene group of 7 to 12. However, an oxygen atom or a sulfur atom may be present between carbon-carbons of the alkylene chain of the alkanediyl group and aralkylene group, and X ¹ , X ² and Y At least one of them is a group containing a sulfur atom, and Ar ¹ and Ar ² are each independently an arylene group having 6 to 30 carbon atoms or an aralkylene group having 7 to 30 carbon atoms. Part or all of the hydrogen atoms of the radical The moiety may be substituted with a substituent, m and n are each independently an integer of 1 to 5. p is an integer of 0 to 10. When m is 2 or more, a plurality of R ¹ and X ¹ may be the same or different, and when n is 2 or more, a plurality of R ² and X ² may be the same or different, and when p is 2 or more, a plurality Y and Ar ² may be the same or different.) The radiation sensitive composition for nanoimprints according to claim 1 , further comprising a polymerizable compound containing no sulfur atom. The polymerizable compound containing no sulfur atom, to claim 2 is at least one compound selected from the group consisting of compounds represented by the compounds and the following formula is represented by the following formula (2) (3) The radiation sensitive composition for nanoimprints as described.

(In Formula (2), R ³ is a hydrogen atom or an s-valent organic group. S is 1 or 2. R ^C is a hydrogen atom or a methyl group. T is 0 or 1. However, when s is 2, two R ^C and t may be the same or different from each other.
In formula (3), R ⁴ is a chain hydrocarbon group or alicyclic hydrocarbon group having 4 to 20 carbon atoms. Part or all of the hydrogen atoms of the chain hydrocarbon group and alicyclic hydrocarbon group may be substituted with a substituent. R ^D and R ^E are each independently a hydrogen atom or a methyl group. ) The radiation-sensitive composition for nanoimprint according to claim 1 , further comprising a non-polymerizable compound containing a fluorine atom. (1) A step of forming a coating film on a substrate using the radiation-sensitive composition for nanoimprints according to any one of claims 1 to 4 ,
(2) a step of pressing a mold having a concavo-convex pattern on the surface against the coating film,
(3) A process of forming the pattern forming layer by exposing the coating film in a state where the mold is pressed.
(4) A pattern forming method including a step of peeling the mold from the pattern forming layer, and (5) a step of etching the pattern forming layer.

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