Lithography sublayer forming composition, lithography sublayer, positive type resist composition, resist film, and method for forming a resist pattern

Abstract

A lithography sublayer forming composition comprising a polymer comprising repeating units derived from an iodine-containing monomer represented by the following general formula (1), and a positive resist composition comprising a polymer comprising repeating units derived from an iodine-containing monomer represented by the following formula (1). (In the formula, X1 is a hydrogen atom, a methyl group, or a halogen atom, Y1 is -O- or -NH-, a is 0 or 1, and R is a carbon 2 to 30 group containing an iodine atom.)

Description

Technology Field

[0001] The invention relates to a composition for forming a lithography sublayer, a lithography sublayer, a positive-type resist composition, a resist film, and a method for forming a resist pattern. Background Technology

[0002] In the manufacture of semiconductor devices, microfabrication is performed by lithography using photoresist materials, but recently, with the high integration and high speed of LSI (large-scale integrated circuits), additional miniaturization by pattern rules is required.

[0003] Conventional resist materials to date are polymer-based resist materials capable of forming amorphous thin films. Examples of polymer-based resist materials include polymethyl methacrylate, polyhydroxystyrene having acid-dissociating groups, or polyalkyl methacrylate.

[0004] Recently, photoresist materials capable of responding to further pattern miniaturization are being developed.

[0005] For example, Patent Document 1 discloses a lithography composition comprising a resin having a constituent unit derived from a compound having a specific amount of atoms of iodine, tellurium, and fluorine, as a high-sensitivity material. Prior art literature

[0006] International Publication No. 2021 / 157551 The problem to be solved

[0007] It is difficult to improve sensitivity in conventionally used lithography materials. In addition, conventionally developed high-sensitivity lithography materials had problems such as insufficient pattern quality, including large pattern defects or roughness, or insufficient etching resistance. Taking these situations into account, there was a demand for a lithography material with higher sensitivity that improves upon the above problems.

[0008] Accordingly, the first problem to be solved by the present invention is to provide a lithography sublayer forming composition capable of increasing the exposure sensitivity of a lithography process, a lithography sublayer, and a resist pattern forming method.

[0009] Furthermore, the second problem that the present invention aims to solve is to provide a positive-type resist composition having excellent resolution, etching resistance, and excellent resist sensitivity characteristics, a resist film using the same, and a method for forming a resist pattern. means of solving the problem

[0010] The inventors have discovered that, regarding the first problem, a lithography sublayer forming composition containing a polymer containing repeating units derived from a specific iodine-containing monomer can solve the problem.

[0011] The inventors have discovered that, regarding the second problem, a positive-type resist composition comprising a polymer containing repeating units derived from a specific iodine-containing monomer can solve the problem.

[0012] That is, the present invention is as follows.

[0013] <1> A lithography sublayer forming composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by the following general formula (1A).

[0014] [Chemical Formula 1]

[0015]

[0016] (during food, X 1A is a hydrogen atom, a methyl group, or a halogen atom, and Y 1A is -O- or -NH-, aa is 0 or 1, and R A is an organic group containing iodine atoms with 2 to 30 carbon atoms.

[0017] <2> R Aa, an organic matrix represented by the following general formula (2A), above <1> Lithography underlayer forming composition described in

[0018] [Chemical Formula 2]

[0019]

[0020] (during food, L A is a directly bonded or divalent organic group having 1 to 24 carbon atoms. ba is an integer from 1 to 5.)

[0021] <3> R A a. at least one selected from the group consisting of an organic group represented by the following general formula (3A) and an organic group represented by the following general formula (4A), the above <1> or <2> Lithography underlayer forming composition described in

[0022] [Chemical Formula 3]

[0023]

[0024] (during food, L A is a directly bonded, or a divalent organic group having 1 to 24 carbon atoms.

[0025] <4> The above, additionally containing a solvent <1> ~ <3> A lithography underlayer forming composition described in any one of the following.

[0026] <5> The above, comprising at least one selected from the group consisting of acid generating agents and acid crosslinking agents. <1> ~ <4> A lithography underlayer forming composition described in any one of the following.

[0027] <6> The above <5> A lithography sublayer formed from a lithography sublayer forming composition described in

[0028] <7> The above <5> A method for forming a resist pattern using a lithography underlayer forming composition described in

[0029] <8> A positive resist composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by the following formula (1B).

[0030] [Chemical Formula 4]

[0031]

[0032] (during food, X 1B is a hydrogen atom, a methyl group, or a halogen atom, and Y 1B is -O- or -NH-, ab is 0 or 1, and R B is a group having 2 to 30 carbon atoms containing an iodine atom.

[0033] <9> R B a, the cause represented by the following formula (2B), above <8> Positive type resist composition described in

[0034] [Chemical Formula 5]

[0035]

[0036] (during food, L B is a directly bonded or divalent group having 1 to 24 carbon atoms, and R 1B Each is independently an alkyl group having 1 to 30 carbon atoms that may have substituents, an aryl group having 6 to 30 carbon atoms that may have substituents, an alkenyl group having 2 to 30 carbon atoms that may have substituents, an alkynyl group having 2 to 30 carbon atoms that may have substituents, an alkoxy group having 1 to 30 carbon atoms that may have substituents, a halogen atom other than iodine, a nitro group, an amino group, a carboxylic acid group, a crosslinking group, a dissociable group, a thiol group, or a hydroxyl group. bb is an integer from 1 to 5, cb is an integer from 0 to 4, and bb+cb is 1 to 5.)

[0037] <10> R B a. At least one selected from the group consisting of a device represented by the following formula (3B) and a device represented by the following formula (4B), the above <8> or <9> Positive type resist composition described in

[0038] [Chemical Formula 6]

[0039]

[0040] (during food, L B is a directly bonded or divalent group having 1 to 24 carbon atoms.

[0041] <11> The above polymer further contains repeating units derived from a phenolic hydroxyl group-containing monomer, the <8> ~ <10> A positive type resist composition as described in any one of the following.

[0042] <12> The above phenolic hydroxyl group-containing monomer is at least one selected from the group consisting of 4-vinylphenol, 4-hydroxyphenyl(meth)acrylate, and 4-hydroxyphenyl(meth)acrylamide, wherein <11> Positive type resist composition described in

[0043] <13> The above phenolic hydroxyl group-containing monomer is 4-vinylphenol, the above <11> or <12> Positive type resist composition described in

[0044] <14> The molar ratio [phenolic hydroxyl group-containing monomer / iodine-containing monomer] of the repeating unit derived from the phenolic hydroxyl group-containing monomer to the repeating unit derived from the iodine-containing monomer represented by the above formula (1B) is 20 / 80 to 95 / 5, the above <11> ~ <13> A positive type resist composition as described in any one of the following.

[0045] <15> The above polymer further contains repeating units derived from an adamantane structure-containing monomer, the above <8> ~ <14> A positive type resist composition as described in any one of the following.

[0046] <16> The above adamantane structure-containing monomer is at least one selected from the group consisting of adamantane-1-yl(meth)acrylate, 2-methyladamantan-2-yl(meth)acrylate, 2-ethyladamantan-2-yl(meth)acrylate, and N-(1-adamanthyl)(meth)acrylamide, wherein <15> Positive type resist composition described in

[0047] <17> The above adamantane structure-containing monomer is 2-methyladamantan-2-yl(meth)acrylate, the above <15> or <16> Positive type resist composition described in

[0048] <18> The molar ratio [adamantane structure-containing monomer / iodine-containing monomer] of the repeating unit derived from the adamantane structure-containing monomer to the repeating unit derived from the iodine-containing monomer represented by the above formula (1B) is 20 / 80 to 99 / 1, the <15> ~ <17> A positive type resist composition as described in any one of the following.

[0049] <19> The above, which further comprises a solvent <8> ~ <18> A positive type resist composition as described in any one of the following.

[0050] <20> The above further comprises at least one selected from the group consisting of acid generating agents and crosslinking agents. <8> ~ <19> A positive type resist composition as described in any one of the following.

[0051] <21> The above <8> ~ <20> A resist film formed from a positive type resist composition described in any one of the above.

[0052] <22> The above <8> ~ <20> A method for forming a resist pattern using a positive type resist composition described in any one of the above.

[0053] <23> On the substrate, the above <8> ~ <20> A process for forming a resist film using a positive-type resist composition described in any one of the above, and

[0054] A method for forming a resist pattern, comprising a process of irradiating the resist film with radiation and performing a development. Effects of the invention

[0055] According to the first invention of the present invention, a composition for forming a lithography sublayer and a lithography sublayer capable of increasing the exposure sensitivity of a lithography process can be provided. Furthermore, a method for forming a resist pattern can be provided.

[0056] In addition, according to the second invention of the present invention, a positive-type resist composition having excellent resolution, etching resistance, and excellent resist sensitivity characteristics, a resist film using the same, and a method for forming a resist pattern can be provided. Specific details for implementing the invention

[0057] [Lithography sublayer forming composition (First invention)]

[0058] The lithography sublayer forming composition in the first invention of the present invention is a lithography sublayer forming composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by the following general formula (1A).

[0059] [Chemical Formula 7]

[0060]

[0061] (during food, X 1A is a hydrogen atom, a methyl group, or a halogen atom, and Y 1A is -O- or -NH-, aa is 0 or 1, and R A is an organic group containing iodine atoms with 2 to 30 carbon atoms.

[0062] Meanwhile, hereinafter, "the present invention" means "the first invention of the present invention," "the second invention of the present invention," or an invention comprising both "the first invention of the present invention" and "the second invention of the present invention."

[0063] That is, the lithography sublayer forming composition of the present invention is a lithography sublayer forming composition containing the polymer, wherein the polymer is a polymer containing repeating units derived from an iodine-containing monomer represented by the general formula (1A).

[0064] Polymer

[0065] The polymer contained in the lithography sublayer forming composition of the present invention is a polymer containing repeating units derived from an iodine-containing monomer represented by the following general formula (1A). The polymer may be in a straight chain or a branched chain, preferably in a straight chain. In addition, the polymer may contain only repeating units derived from one type of iodine-containing monomer, or may contain repeating units derived from two or more types of iodine-containing monomers.

[0066] By including the polymer in the lithography underlayer forming composition of the present invention, the exposure sensitivity of the lithography process can be increased.

[0067] [Chemical Formula 8]

[0068]

[0069] (during food, X 1A is a hydrogen atom, a methyl group, or a halogen atom, and Y 1A is -O- or -NH-, aa is 0 or 1, and R A is an organic group containing iodine atoms with 2 to 30 carbon atoms.

[0070] Although it is not certain why the lithography sublayer forming composition and the lithography sublayer of the present invention can increase the exposure sensitivity of the lithography process, it is thought to be as follows.

[0071] In particular, when EUV is used as a lithography light source, it is thought that the sensitivity of the resist can be improved because, even though EUV is used which is easy to transmit through the resist film and tends to lower the exposure sensitivity, the lower layer of the present invention containing an iodine-containing polymer can absorb EUV light and supply secondary electrons or protons to the resist layer.

[0072] Furthermore, by utilizing the lithography underlayer forming composition containing the above-mentioned polymer as the underlayer of the resist layer, it is believed that the collapse of the resist pattern or the deterioration of the resist pattern shape is suppressed, and higher resolution becomes possible. In this way, it is believed that by utilizing the lithography underlayer forming composition and the lithography underlayer of the present invention, the exposure sensitivity of the lithography process can be increased.

[0073] (Iodine-containing monomer represented by formula (1A))

[0074] The iodine-containing monomer used as a raw material for the above polymer is represented by the following general formula (1A).

[0075] [Chemical Formula 9]

[0076]

[0077] (during food, X 1A is a hydrogen atom, a methyl group, or a halogen atom, and Y 1A is -O- or -NH-, aa is 0 or 1, and R A is an organic group containing iodine atoms with 2 to 30 carbon atoms.

[0078] In equation (1A), X 1A is a hydrogen atom, a methyl group, or a halogen atom, preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0079] In equation (1A), Y 1A is -O- or -NH-, preferably -O-.

[0080] In formula (1A), aa is 0 or 1, preferably 1.

[0081] In equation (1A), R AThe is an organic group comprising an iodine atom having 2 to 30 carbon atoms, preferably an organic group represented by the following general formula (2A), more preferably at least one selected from the group consisting of an organic group represented by the following general formula (3A) and an organic group represented by the following general formula (4A), and even more preferably an organic group represented by the following general formula (3A). In particular, by selecting a monomer having an organic group represented by formula (3A), a polymer with excellent molecular weight controllability, solubility, and film-forming properties can be obtained.

[0082] [Chemical Formula 10]

[0083]

[0084] (In Equation (2A), L A is a directly bonded or divalent organic group having 1 to 24 carbon atoms. ba is an integer from 1 to 5. In formula (3A), L A is a direct bond, or a divalent organic group having 1 to 24 carbon atoms. In formula (4A), L A is a directly bonded, or a divalent organic group having 1 to 24 carbon atoms.

[0085] In formula (2A), ba is an integer from 1 to 5, preferably an integer from 1 to 3, more preferably 1 or 3, and even more preferably 3. In particular, by selecting a monomer having a triiodophenyl group where ba is 3, a polymer with excellent molecular weight controllability, solubility, and film-forming properties can be obtained. When ba is 3, L A The triiodophenyl group bonded to is preferably a 2,3,5-triiodophenyl group or a 2,4,6-triiodophenyl group, and more preferably a 2,4,6-triiodophenyl group.

[0086] L in equations (2A), (3A) and (4A) A They may be identical or different, but either is preferably a direct combination.

[0087] L in equations (2A), (3A) and (4A)A Even if the organic group is a divalent organic group having 1 to 24 carbon atoms, they may be the same or different, but the preferred organic group is the same.

[0088] The divalent organic group having 1 to 24 carbon atoms may be an aliphatic or aromatic group, preferably an aliphatic group, and more preferably an alkylene group or a (poly)oxyalkylene group.

[0089] L A If α is an alkylene group, L A The number of carbon atoms is preferably 1 to 24, and more preferably 2 to 24.

[0090] L A If is a (poly)oxyalkylene group, L A The number of oxygen atoms in is preferably 1 to 12. L A The number of carbon atoms is preferably 1 to 24, and more preferably 2 to 24.

[0091] L A If is a (poly)oxyalkylene group, L A The group is preferably a (poly)oxyethylene group, a (poly)oxypropylene group, or a (poly)oxybutylene group, and more preferably a (poly)oxyethylene group.

[0092] (Other monomers)

[0093] As a raw material for the above polymer, other monomers other than the iodine-containing monomer may be used. That is, the lithography sublayer forming composition of the present invention may be a lithography sublayer forming composition containing a polymer containing a repeating unit derived from an iodine-containing monomer represented by formula (1A) and a repeating unit derived from a monomer other than the iodine-containing monomer. Meanwhile, the polymer may contain only one type of repeating unit derived from the other monomer, or may contain two or more types of repeating units derived from the other monomer.

[0094] Other monomers other than the iodine-containing monomer represented by formula (1A) include (meth)acrylate monomers, styrene monomers, (meth)acrylamide monomers, nitrile-containing vinyl monomers, vinyl halides, vinylidene halides, vinyl acetate, etc., and preferably (meth)acrylate monomers. By including (meth)acrylate monomers other than the iodine-containing monomer represented by formula (1A), film-forming properties are improved.

[0095] Examples of styrene-based monomers include styrene, p-methylstyrene, α-methylstyrene, styrene halides, vinyl benzoic acid, 4-vinylbenzenesulfonic acid, 4-vinylbenzenesulfonic acid esters, and 4-vinylbenzenesulfonamide.

[0096] Examples of (meth)acrylamide-based monomers include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, etc.

[0097] Examples of vinyl monomers containing nitrile groups include (meth)acrylonitrile.

[0098] Examples of (meth)acrylate-based monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, glycidyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, Nt-butylaminoethyl (meth)acrylate, polyalkylene glycol (meth)acrylate, etc., and preferably 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate. Hydroxybutyl methacrylate, glycidyl methacrylate, and polyalkylene glycol (meth)acrylate are more preferably 2-hydroxyethyl methacrylate, glycidyl methacrylate, and polyethylene glycol (meth)acrylate, even more preferably 2-hydroxyethyl methacrylate, polyalkylene glycol (meth)acrylate, and even more preferably polyalkylene glycol (meth)acrylate.

[0099] As for the polyalkylene glycol (meth)acrylate, preferably it is polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, or polybutylene glycol (meth)acrylate; more preferably it is polyethylene glycol (meth)acrylate or polypropylene glycol (meth)acrylate; and even more preferably it is polyethylene glycol (meth)acrylate.

[0100] (Molecular weight control agent)

[0101] A molecular weight control agent may be used as a raw material for the above polymer. That is, the lithography sublayer forming composition of the present invention may be a lithography sublayer forming composition containing a polymer containing a repeating unit derived from an iodine-containing monomer represented by formula (1A) and a structure derived from a molecular weight control agent, or a lithography sublayer forming composition containing a polymer containing a repeating unit derived from an iodine-containing monomer represented by formula (1A), a repeating unit derived from a monomer other than the iodine-containing monomer, and a structure derived from a molecular weight control agent. Meanwhile, the above polymer may contain only one type of structure derived from a molecular weight control agent, or may contain two or more types of structures derived from a molecular weight control agent.

[0102] The above molecular weight control agent refers to an additive capable of controlling the molecular weight range by inhibiting polymerization, and is typically a chain transfer agent. It is preferable that the molecular weight control agent be an aromatic compound. Examples of molecular weight control agents include various chain transfer agents, RAFT agents, NMP agents, ATRP agents, and TERP agents, and sulfur-containing chain transfer agents such as thiol-type chain transfer agents and RAFT agents are preferred. These may be used alone or in combination of two or more types.

[0103] The thiol-type chain transfer agent may be a monothiol compound, a dithiol compound, a trithiol compound, or a polythiol compound of tetrathiol or more, and it is preferable that it be a monothiol compound or a dithiol compound. The thiol-type chain transfer agent may be a thiol compound having a sulfur atom in addition to a thiol group. The thiol compound may be a molecule composed only of carbon, hydrogen, and sulfur.

[0104] Specific examples of thiol-type chain transfer agents include aliphatic monothiol compounds, aliphatic polythiol compounds, aliphatic thiols containing a sulfur atom other than a mercapto group, aromatic monothiol compounds, aromatic polythiols, aromatic polythiol compounds containing a sulfur atom other than a mercapto group, heterocyclic compounds containing a sulfur atom other than a mercapto group, compounds containing a hydroxyl group other than a mercapto group, and derivatives thereof. Aromatic monothiol compounds and aromatic polythiol compounds containing a sulfur atom other than a mercapto group are preferred, and bis(4-mercaptophenyl)sulfide (4,4'-thiobisbenzenethiol) and 4-mercaptopyridine are more preferred. These may be used alone or in combination of two or more types.

[0105] Aliphatic monothiol compounds include methanethiol, ethanethiol, propanethiol, butanethiol, cyclohexanediol, etc.

[0106] Aliphatic polythiol compounds include methanedithiol, 1,2-ethanedithiol, 1,1-propanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 2,2-propanedithiol, 1,6-hexanedithil, 1,2,3-propanetrithiol, 1,1-cyclohexanedithil, 1,2-cyclohexanedithil, 2,2-dimethylpropane-1,3-dithiol, 3,4-dimethoxybutane-1,2-dithiol, 2-methylcyclohexane-2,3-dithiol, 1,1-bis(mercaptomethyl)cyclohexane, bis(2-mercaptoethyl ester) thiosaganate, and 2,3-dimercapto-1-propanol (2-mercaptoacetate). Examples include 2,3-dimercapto-1-propanol (3-mercaptopropionate), diethylene glycol bis(2-mercaptoacetate), diethylene glycol bis(3-mercaptopropionate), 1,2-dimercaptopropylmethyl ether, 2,3-dimercaptopropylmethyl ether, 2,2-bis(mercaptomethyl)-1,3-propanedithiol, bis(2-mercaptoethyl) ether, ethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(3-mercaptopropionate), trimethylolpropane bis(2-mercaptoacetate), trimethylolpropane bis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), tetrakis(mercaptomethyl)methane, etc.

[0107] Aliphatic thiols containing a sulfur atom other than a mercapto group include bis(mercaptomethyl)sulfide, bis(mercaptoethyl)sulfide, bis(mercaptopropyl)sulfide, bis(mercaptomethylthio)methane, bis(2-mercaptoethylthio)methane, bis(3-mercaptopropyl)methane, 1,2-bis(mercaptomethylthio)ethane, 1,2-(2-mercaptoethylthio)ethane, 1,2-(3-mercaptopropyl)ethane, 1,3-bis(mercaptomethylthio)propane, 1,3-bis(2-mercaptoethylthio)propane, 1,3-bis(3-mercaptopropylthio)propane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 2-mercaptoethylthio-1,3-propanedithiol, 1,2,3-Tris(mercaptomethylthio)propane, 1,2,3-Tris(2-mercaptoethylthio)propane, 1,2,3-Tris(3-mercaptopropylthio)propane, Tetrakis(mercaptomethylthiomethyl)methane, Tetrakis(2-mercaptoethylthiomethyl)methane, Tetrakis(3-mercaptopropylthiomethyl)methane, Bis(2,3-dimercaptopropyl)sulfide, 2,5-dimercapto-1,4-dithiane, Bis(mercaptomethyl)disulfide, Bis(mercaptoethyl)disulfide, Bis(mercaptopropyl)disulfide, 4-mercaptomethyl-3,6-dithioctan-1,8-dithiol, Bis(mercaptomethyl)-3,6,9-trithi-1,11-undecanedithiol, Bis(1,3-dimercapto-2-propyl)sulfide, hydroxymethylsulfidebis(2-mercaptoacetate), hydroxymethylsulfidebis(3-mercaptopropionate), hydroxyethylsulfidebis(2-mercaptoacetate), hydroxyethylsulfidebis(3-mercaptopropionate), hydroxypropylsulfidebis(2-mercaptoacetate), hydroxypropylsulfidebis(3-mercaptopropionate), hydroxymethyldisulfidebis(2-mercaptoacetate), hydroxymethyldisulfidebis(3-mercaptopropionate), hydroxyethyldisulfidebis(2-mercaptoacetate), hydroxyethyldisulfidebis(3-mercaptopropionate), hydroxypropyldisulfidebis(2-mercaptoacetate), Hydroxypropyldisulfidebis(3-mercaptopropionate),2-Mercaptoethyl etherbis(2-mercaptoacetate), 2-Mercaptoethyl etherbis(3-mercaptopropionate), 1,4-Dithian-2,5-Diolbis(2-mercaptoacetate), 1,4-Dithian-2,5-Diolbis(3-mercaptopropionate), thioglycolate bis(2-mercaptoethyl ester), thiodipropionicate bis(2-mercaptoethyl ester), 4,4'-thiodibutyricate bis(2-mercaptoethyl ester), dithiodiglycolate bis(2-mercaptoethyl ester), dithiodipropionicate bis(2-mercaptoethyl ester), 4,4'-dithiodibutyricate bis(2-mercaptoethyl ester), thiodiglycolate bis(2,3-dimercaptopropyl ester), Examples include bis(2,3-dimercaptopropyl ester) of thiodipropionic acid, bis(2,3-dimercaptopropyl ester) of dithiodiglylic acid, and dithiodipropionic acid (2,3-dimercaptopropyl ester).

[0108] Examples of aromatic monothiol compounds include benzenethiol, o-methyl-α-toluenthiol, o-toluenthiol, m-toluenthiol, p-toluenthiol, 1-naphthalenethiol, 2-naphthalenethiol, 4-mercaptopyridine, etc., and 4-mercaptopyridine is preferred.

[0109] Aromatic polythiols include 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, 1,2-bis(mercaptoethyl)benzene, 1,3-bis(mercaptoethyl)benzene, 1,4-bis(mercaptoethyl)benzene, 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3-tris(mercaptomethyl)benzene, 1,2,4-tris(mercaptomethyl)benzene, 1,3,5-tris(mercaptomethyl)benzene, Examples include 1,2,3-tris(mercaptoethyl)benzene, 1,2,4-tris(mercaptoethyl)benzene, 1,3,5-tris(mercaptoethyl)benzene, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,3-di(p-methoxyphenyl)propane-2,2-dithiol, 1,3-diphenylpropane-2,2-dithiol, phenylmethane-1,1-dithiol, and 2,4-di(p-mercaptophenyl)pentane.

[0110] Aromatic polythiol compounds containing sulfur atoms other than mercapto groups include 1,2-bis(mercaptomethylenethio)benzene, 1,3-bis(mercaptomethylenethio)benzene, 1,4-bis(mercaptomethylenethio)benzene, 1,2-bis(mercaptomethylenethio)benzene, 1,3-bis(mercaptomethylenethio)benzene, 1,4-bis(mercaptomethylenethio)benzene, 1,2-bis(mercaptompropylenethio)benzene, 1,3-bis(mercaptompropylenethio)benzene, 1,4-bis(mercaptompropylenethio)benzene, 1,2-bis(mercaptomethylenethiomethylene)benzene, 1,3-bis(mercaptomethylenethiomethylene)benzene, 1,4-bis(mercaptomethylenethiomethylene)benzene, 1,2-Bis(mercaptopropylenethiomethylene)benzene, 1,3-Bis(mercaptopropylenethiomethylene)benzene, 1,4-Bis(mercaptopropylenethiomethylene)benzene, Bis(4-mercaptophenyl)sulfide(4,4'-thiobisbenzenethiol), Bis(3-mercaptophenyl)sulfide, 4,4'-oxybisbenzenethiol, 4,4'-biphenyldithiol, 1,2-Bis(mercaptomethyleneoxy)benzene, 1,3-Bis(mercaptomethyleneoxy)benzene, 1,4-Bis(mercaptomethyleneoxy)benzene, 1,2-Bis(mercaptoethyleneoxy)benzene, 1,3-Bis(mercaptomethyleneoxy)benzene, 1,4-Bis(mercaptomethyleneoxy)benzene, 1,2-Bis(mercaptomethyleneoxy)benzene, Examples include 1,3-bis(mercaptoethyleneoxymethylene)benzene, 1,4-bis(mercaptoethyleneoxymethylene)benzene, 1,2-bis(mercaptopropyleneoxymethylene)benzene, 1,3-bis(mercaptopropyleneoxymethylene)benzene, 1,4-bis(mercaptopropyleneoxymethylene)benzene, 1,3,5-trimercaptobenzene, 1,2,3-tris(mercaptomethylthio)benzene, 1,2,4-tris(mercaptomethylthio)benzene, 1,3,5-tris(mercaptomethylthio)benzene, 1,2,3-tris(mercaptoethylthio)benzene, 1,2,4-tris(mercaptoethylthio)benzene, 1,3,5-tris(mercaptoethylthio)benzene, etc. Bis(4-mercaptophenyl)sulfide (4,4'-thiobisbenzenethiol) is preferred.

[0111] Examples of heterocyclic compounds containing sulfur atoms other than mercapto groups include 3,4-thiopendithiol and 2,5-dimercapto-1,3,4-thiadiazole.

[0112] Compounds containing a hydroxyl group other than a mercapto group include 2-mercaptoethanol, 3-mercapto-1,2-propanediol, glycerin di(mercaptoacetate), 1-hydroxy-4-mercaptocyclohexane, 2,4-dimercaptophenol, 2-mercaptohydroquinone, 4-mercaptophenol, 3,4-dimercapto-2-propanol, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1,2-dimercapto-1,3-butanediol, pentaerythritol tris(3-mercaptopropionate), pentaerythritol mono(3-mercaptopropionate), pentaerythritol bis(3-mercaptopropionate), pentaerythritol tris(thioglycolate), Examples include dipentaerythritol pentakis(3-mercaptopropionate), hydroxymethyl-tris(mercaptoethylthiomethyl)methane, 1-hydroxyethylthio-3-mercaptoethylthiobenzene, etc.

[0113] Specific examples of RAFT agents include dithioesters, trithiocarbonates, dithiocarbamates, and disulfides. These may be used alone or in combination of two or more types.

[0114] Examples of dithioesters include 2-cyano-2-propylbenzodithioate and 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid.

[0115] Examples of trithiocarbonates include 2-cyano-2-propyldodecyl trithiocarbonate, 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid, 2-(dodecylthiocarbonothioilthio)-2-methylpropionic acid, and cyanomethyldodecyl trithiocarbonate.

[0116] Examples of dithiocarbamates include cyanomethylmethyl(phenyl)carbamodithioate.

[0117] Examples of disulfides include bis(thiobenzoyl)disulfide and bis(dodecylsulfanylthiocarbonyl)disulfide.

[0118] (Composition of polymer)

[0119] The content of repeating units derived from the iodine-containing monomer represented by formula (1A) is preferably 20 to 100 mass% in the polymer, more preferably 40 to 100 mass%, even more preferably 50 to 100 mass%, even more preferably 70 to 100 mass%, and even more preferably 80 to 100 mass%, and may consist only of repeating units derived from the iodine-containing monomer represented by formula (1A), and even more preferably 80 to 90 mass%.

[0120] When the above polymer contains repeating units derived from a (meth)acrylate-based monomer other than the iodine-containing monomer represented by formula (1A), the content of repeating units derived from the (meth)acrylate-based monomer is preferably 1 to 80 mass%, more preferably 3 to 60 mass%, even more preferably 5 to 50 mass%, even more preferably 6 to 30 mass%, even more preferably 8 to 20 mass%, and even more preferably 10 to 20 mass% of the polymer. By containing the (meth)acrylate-based monomer other than the iodine-containing monomer represented by formula (1A) within the above range, the film-forming properties are improved.

[0121] In the case where the above polymer contains repeating units derived from (meth)acrylate-based monomers other than the iodine-containing monomer represented by formula (1A), the content of repeating units derived from the iodine-containing monomer represented by formula (1A) is preferably 20 to 99 mass%, more preferably 40 to 97 mass%, even more preferably 50 to 95 mass%, even more preferably 70 to 92 mass%, even more preferably 80 to 92 mass%, and even more preferably 80 to 90 mass%.

[0122] When the above polymer contains repeating units derived from a (meth)acrylate-based monomer other than the iodine-containing monomer represented by formula (1A), the molar ratio [iodine-containing monomer / (meth)acrylate-based monomer] of the repeating unit derived from the iodine-containing monomer represented by formula (1A) and the repeating unit derived from the (meth)acrylate-based monomer is preferably 20 / 80 to 99 / 1, more preferably 40 / 60 to 97 / 3, even more preferably 50 / 50 to 95 / 5, even more preferably 70 / 30 to 92 / 8, even more preferably 80 / 20 to 92 / 8, and even more preferably 80 / 20 to 90 / 10.

[0123] When the above polymer contains a structure derived from a molecular weight control agent, the content of the structure derived from the molecular weight control agent is preferably 1 to 80 mass%, more preferably 3 to 60 mass%, even more preferably 5 to 50 mass%, even more preferably 6 to 30 mass%, even more preferably 8 to 20 mass%, and even more preferably 10 to 20 mass% of the above polymer.

[0124] The content of repeating units derived from iodine-containing monomers represented by formula (1A) in the case where the polymer contains a structure derived from a molecular weight control agent is preferably 20 to 99 mass%, more preferably 40 to 97 mass%, even more preferably 50 to 95 mass%, even more preferably 70 to 92 mass%, even more preferably 80 to 92 mass%, and even more preferably 80 to 90 mass%.

[0125] When the above polymer contains a structure derived from a molecular weight control agent, the molar ratio [iodine-containing monomer / molecular weight control agent] of the repeating unit derived from the iodine-containing monomer represented by formula (1A) and the structure derived from the molecular weight control agent is preferably 20 / 80 to 99 / 1, more preferably 40 / 60 to 97 / 3, even more preferably 50 / 50 to 95 / 5, even more preferably 70 / 30 to 92 / 8, even more preferably 80 / 20 to 92 / 8, and even more preferably 80 / 20 to 90 / 10.

[0126] (Molecular weight of the polymer)

[0127] The number average molecular weight of the polymer is preferably 500 to 100,000, more preferably 1,000 to 50,000, even more preferably 2,000 to 40,000, even more preferably 3,000 to 30,000, even more preferably 5,000 to 25,000, even more preferably 10,000 to 20,000, and even more preferably 10,000 to 15,000. By having the number average molecular weight of the polymer within the above range, the solubility and film-forming properties of the polymer are excellent. The number average molecular weight is the molecular weight converted to polystyrene.

[0128] The molecular weight distribution (Mw / Mn) of the polymer is preferably 1.3 to 7.5, more preferably 1.3 to 7.0, even more preferably 1.3 to 6.0, even more preferably 1.3 to 5.0, even more preferably 1.3 to 4.0, even more preferably 1.3 to 3.0, even more preferably 1.5 to 3.0, and even more preferably 2.0 to 3.0.

[0129] Method for manufacturing polymers

[0130] The polymer contained in the lithography sublayer forming composition of the present invention is a polymer containing repeating units derived from an iodine-containing monomer represented by formula (1A), and there are no limitations on the method of manufacture thereof, but it is preferable to follow the method below.

[0131] The method for manufacturing the above polymer can be obtained by a process of polymerizing the above monomer, which is a raw material. The above process may be a process of polymerizing the monomer in the presence of a molecular weight control agent. By polymerizing the monomer in the presence of a molecular weight control agent, the molecular weight can be controlled, and the obtained polymer can be made to have a target molecular weight.

[0132] The polymerization method in the above process is not particularly limited. Examples of polymerization methods include bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., and preferably, solution polymerization.

[0133] In addition, polymerization methods include radical polymerization, anionic polymerization, and cationic polymerization, and preferably radical polymerization. A suitable polymerization method can be selected depending on the type of monomer, polymerization temperature, etc.

[0134] In the polymerization process described above, it is preferable to use a polymerization initiator.

[0135] The polymerization initiator can be selected depending on the type of monomer, polymerization temperature, etc.

[0136] Examples of polymerization initiators include azo-based initiators and peroxide-based initiators, and preferably, azo-based initiators.

[0137] Examples of azo-based initiators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,2-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2-amidinopropane)dihydrochloride, etc., and 2,2'-azobis(isobutyronitrile) is preferred.

[0138] Examples of peroxide-based initiators include benzoyl peroxide, di-t-butyl hydroperoxide, t-butyl hydroperoxide, cumyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, benzoyl peroxide, dicumyl peroxide, ethyl 3,3-di(t-amylperoxy)butyrate, potassium sulfate, ammonium persulfate, etc.

[0139] Polymerization initiators may be used alone or in combination of two or more types.

[0140] The amount of polymerization initiator used can be appropriately changed depending on the type of monomer or the type of polymerization initiator, and with respect to the total amount of monomer, it is preferably 0.1 to 50 mol%, more preferably 0.5 to 30 mol%, even more preferably 1 to 20 mol%, even more preferably 2 to 10 mol%, and even more preferably 3 to 5 mol%.

[0141] When polymerization in the above process is carried out as solution polymerization, it is desirable to select a suitable solvent considering the solubility of the monomer or polymerization initiator and the polymerization temperature, and to carry out the polymerization in that solvent.

[0142] Examples of solvents used in the above process include DMF, N-methyl-2-pyrrolidone, acetone, THF, benzene, toluene, ethylbenzene, xylene, chlorobenzene, methyl ethyl ketone, ethyl lactic acid, isopropyl alcohol, etc. These may be used individually or in combination of two or more types.

[0143] The amount of monomer used as a raw material can be adjusted to obtain a polymer of the desired composition. Specifically, it is preferable to use the following amounts.

[0144] The amount of iodine-containing monomer represented by formula (1A) used is preferably 20 to 100 mass% with respect to the total amount of monomer and molecular weight control agent, more preferably 40 to 100 mass%, even more preferably 50 to 100 mass%, even more preferably 70 to 100 mass%, and even more preferably 80 to 100 mass%, and may consist only of iodine-containing monomer represented by formula (1A), more preferably 80 to 90 mass%.

[0145] When the raw monomer contains a (meth)acrylate-based monomer other than the iodine-containing monomer represented by Formula (1A), the amount of this (meth)acrylate-based monomer used is preferably 1 to 80 mass%, more preferably 3 to 60 mass%, even more preferably 5 to 50 mass%, even more preferably 6 to 30 mass%, even more preferably 8 to 20 mass%, and even more preferably 10 to 20 mass% with respect to the total amount of the monomer and the molecular weight control agent. By using a (meth)acrylate-based monomer other than the iodine-containing monomer represented by Formula (1A), the film-forming properties are improved.

[0146] In the case where the raw material monomer contains a (meth)acrylate-based monomer other than the iodine-containing monomer represented by formula (1A), the amount of iodine-containing monomer represented by formula (1A) used is preferably 20 to 99 mass% with respect to the total amount of monomer and molecular weight control agent, more preferably 40 to 97 mass%, even more preferably 50 to 95 mass%, even more preferably 70 to 92 mass%, even more preferably 80 to 92 mass%, and even more preferably 80 to 90 mass%.

[0147] When the raw material monomer contains a (meth)acrylate-based monomer other than the iodine-containing monomer represented by formula (1A), the molar ratio [iodine-containing monomer / (meth)acrylate-based monomer] of the iodine-containing monomer represented by formula (1A) and the (meth)acrylate-based monomer is preferably 20 / 80 to 99 / 1, more preferably 40 / 60 to 97 / 3, even more preferably 50 / 50 to 95 / 5, even more preferably 70 / 30 to 92 / 8, even more preferably 80 / 20 to 92 / 8, and even more preferably 80 / 20 to 90 / 10.

[0148] When the raw material contains a molecular weight control agent, the amount of the molecular weight control agent used is preferably 1 to 80 mass%, more preferably 3 to 60 mass%, even more preferably 5 to 50 mass%, even more preferably 6 to 30 mass%, even more preferably 8 to 20 mass%, and even more preferably 10 to 20 mass% with respect to the total amount of monomer and molecular weight control agent.

[0149] The amount of iodine-containing monomer represented by formula (1A) in the case where the raw material contains a molecular weight control agent is preferably 20 to 99 mass%, more preferably 40 to 97 mass%, even more preferably 50 to 95 mass%, even more preferably 70 to 92 mass%, even more preferably 80 to 92 mass%, and even more preferably 80 to 90 mass% with respect to the total amount of monomer and molecular weight control agent.

[0150] When the raw material contains a molecular weight control agent, the molar ratio [iodine-containing monomer / molecular weight control agent] of the iodine-containing monomer represented by formula (1A) to the molecular weight control agent is preferably 20 / 80 to 99 / 1, more preferably 40 / 60 to 97 / 3, even more preferably 50 / 50 to 95 / 5, even more preferably 70 / 30 to 92 / 8, even more preferably 80 / 20 to 92 / 8, and even more preferably 80 / 20 to 90 / 10.

[0151] The reaction temperature can be appropriately adjusted according to the decomposition temperature of the polymerization initiator used, preferably 0 to 100°C, more preferably 20 to 80°C, even more preferably 30 to 70°C, even more preferably 40 to 70°C, and even more preferably 50 to 70°C.

[0152] The reaction time can be appropriately adjusted according to the reaction temperature, amount of catalyst, reactivity of the raw material, desired molecular weight, etc., preferably 1 to 72 hours, more preferably 5 to 60 hours, even more preferably 12 to 50 hours, even more preferably 15 to 40 hours, and even more preferably 15 to 30 hours.

[0153] The reaction may be carried out in the presence of a solvent. A preferred solvent is one in which the polymer to be obtained dissolves, more preferably an amide-based solvent, and even more preferably N,N-dimethylformamide.

[0154] It is preferable to purify the obtained polymer by conventional post-treatment. Specifically, it is preferable to remove raw materials or by-products by introducing the reaction mixture into an organic solvent in which the polymer does not dissolve and recovering the target polymer as a precipitate. Additionally, it is preferable to remove catalysts, etc., by dissolving the polymer in an organic solvent in which it dissolves and washing it with water or the like.

[0155] At the end of the reaction or purification process, if the polymer is obtained as a solution dissolved in an organic solvent, it is preferable to concentrate and dry it to obtain a polymer as a solid.

[0156] The polymer obtained as described above has high solubility in solvents and excellent film-forming properties.

[0157] <Composition of Lithography Underlayer Forming Composition>

[0158] The lithography sublayer forming composition of the present invention preferably further contains a solvent in addition to the polymer, and preferably includes at least one selected from the group consisting of an acid generating agent and an acid crosslinking agent.

[0159] Furthermore, other optional components may include acid or base compounds, acid diffusion control agents, organic polymer compounds, surfactants, colorants, and curing catalysts. In terms of coating properties and quality stability, the content of the polymer in the lithography underlayer forming composition is preferably 0.1 to 70 mass%, more preferably 0.5 to 50 mass%, and even more preferably 3.0 to 40 mass%.

[0160] (menstruum)

[0161] The lithography underlayer forming composition of the present invention preferably additionally contains a solvent to improve film formation properties.

[0162] As for the solvent, it is not particularly limited as long as it dissolves other components such as the polymer mentioned above, but the solvents listed below are preferred.

[0163] As solvents, ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, and ethylene glycol mono-n-butyl ether acetate; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, and propylene glycol mono-n-butyl ether acetate; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether (1-methoxy-2-propanol, PGME) and propylene glycol monoethyl ether; and lactic acid esters such as methyl lactic acid, ethyl lactic acid, n-propyl lactic acid, n-butyl lactic acid, and n-amyl lactic acid; Aliphatic carboxylic acid esters such as methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, n-amyl acetate, n-hexyl acetate, methyl propionate, ethyl propionate, etc.; other esters such as methyl methoxypropionate, ethyl methoxypropionate, 3-methyl methoxypropionate, 3-ethyl ethoxypropionate, 3-methoxy-2-methylpropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methoxy-3-methylpropionate, 3-methoxy-3-methylbutyrate butyl, methyl acetoacetate, methyl pyruvate, ethyl pyruvate, etc.; aromatic hydrocarbons such as toluene, xylene, etc.; Examples include ketones such as methyl ethyl ketone (MEK), 2-heptanone, 3-heptanone, 4-heptanone, cyclopentanone (CPN), and cyclohexanone (CHN); amides such as N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpyrrolidone; lactones such as γ-lactone; sulfoxides such as dimethyl sulfoxide (DMSO); halogenated hydrocarbons such as chloroform; and cyclic ethers such as tetrahydrofuran (THF). These solvents may be used alone or in combination of two or more.

[0164] The solvent included in the lithography sublayer forming composition of the present invention is preferably a safe solvent, more preferably at least one selected from PGMEA, PGME, CHN, CPN, 2-heptanone, anisole, butyl acetate, ethyl propionate, and ethyl lactic acid, and even more preferably at least one selected from PGMEA, PGME, and CHN.

[0165] The solvent content of the lithography sublayer forming composition of the present invention is preferably 100 to 10,000 parts by mass with respect to 100 parts by mass of the total solid component (component excluding solvent) of the lithography sublayer forming composition, more preferably 200 to 8,000 parts by mass, and even more preferably 200 to 5,000 parts by mass, in terms of solubility and film formation.

[0166] (Acid generator)

[0167] The lithography sublayer forming composition of the present invention preferably comprises at least one selected from the group consisting of an acid generating agent and an acid crosslinking agent, and more preferably comprises both an acid generating agent and an acid crosslinking agent.

[0168] It is preferable that the acid generator be an acid generator that generates acid directly or indirectly by irradiation with any one of the radiation selected from visible light, ultraviolet light, excimer laser, electron beam, extreme ultraviolet (EUV), X-ray, and ion beam.

[0169] In the lithography underlayer forming composition of the present invention, the content of the acid generator is preferably 0.001 to 49 mass% with respect to the total mass of the solid component (component excluding the solvent), more preferably 1 to 40 mass%, even more preferably 3 to 30 mass%, and even more preferably 10 to 25 mass%. By having the content of the acid generator within the above range, a pattern profile with high sensitivity and low edge roughness is obtained.

[0170] In the lithography sublayer forming composition of the present invention, if acid is generated within the system, the method of generating the acid is not limited. If an excimer laser is used instead of ultraviolet rays such as g-rays or i-rays, finer processing is possible, and further finer processing is possible if electron beams, extreme ultraviolet rays, X-rays, or ion beams are used as high-energy rays.

[0171] The above acid-generating agent is not particularly limited and, for example, may be a compound disclosed in International Publication No. 2017 / 033943.

[0172] The acid generator is preferably an acid generator having an aromatic ring, more preferably an acid generator having a sulfonate ion having an aryl group, and even more preferably at least one selected from the group consisting of diphenyltrimethylphenylsulfonium p-toluenesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, and triphenylsulfonium nonafluoromethanesulfonate. By using the acid generator, line edge roughness can be reduced.

[0173] The lithography sublayer forming composition of the present invention preferably further contains a diazonaphthoquinone photoactive compound as an acid-generating agent. The diazonaphthoquinone photoactive compound is a diazonaphthoquinone material comprising polymeric and non-polymeric diazonaphthoquinone photoactive compounds, and is not particularly limited as long as it is used as a photosensitive component in a positive-type resist composition, and one or more types may be optionally selected and used. Among these, from the viewpoint of low roughness and solubility, it is preferable that it be a non-polymeric diazonaphthoquinone photoactive compound, more preferable that it be a low molecular weight compound, and it is preferable that the molecular weight is 1500 or less, more preferable that it is 1200 or less, and even more preferable that it is 1000 or less. Preferred embodiments of such nonpolymer diazonaphthoquinone photoactive compounds include the nonpolymer diazonaphthoquinone photoactive compound disclosed in International Publication No. 2016 / 158881. The acid generating agent may be used alone or in combination of two or more.

[0174] (Acid crosslinking agent)

[0175] The lithography underlayer forming composition of the present invention preferably includes an acid crosslinking agent to increase the strength of the pattern, whether used as a negative-type resist material or as a positive-type resist material.

[0176] An acid crosslinking agent is a compound capable of crosslinking a polymer (resin) intramolecularly or intermolecularly in the presence of an acid generated from an acid generating agent. Such acid crosslinking agents are not particularly limited, but may include compounds having one or more crosslinking groups capable of crosslinking a polymer (resin).

[0177] Specific examples of crosslinking groups are not particularly limited, but include: (i) hydroxyalkyl groups such as hydroxy (alkyl group having 1 to 6 carbon atoms), alkoxy (alkyl group having 1 to 6 carbon atoms), or acetoxy (alkyl group having 1 to 6 carbon atoms), or groups derived therefrom; (ii) carbonyl groups such as formyl groups or carboxy (alkyl group having 1 to 6 carbon atoms), or groups derived therefrom; (iii) nitrogen-containing groups such as dimethylaminomethyl groups, diethylaminomethyl groups, dimethylolaminomethyl groups, diethylolaminomethyl groups, or morpholinomethyl groups; and (iv) glycidyl-containing groups such as glycidyl ether groups, glycidyl ester groups, or glycidyl amino groups. (v) A group derived from an aromatic group such as a benzyloxymethyl group, a benzoyloxymethyl group, an allyloxy group having 1 to 6 carbon atoms (an alkyl group having 1 to 6 carbon atoms), an aralkyloxy group having 1 to 6 carbon atoms (an alkyl group having 1 to 6 carbon atoms); (vi) A polymerizable multiple bond-containing group such as a vinyl group or an isopropene group. As for the crosslinking group, a hydroxyalkyl group and an alkoxyalkyl group are preferred, and an alkoxymethyl group is more preferred.

[0178] The acid crosslinking agent is not particularly limited, but comprises: (i) compounds containing a methylol group, such as a methylol group-containing melamine compound, a methylol group-containing benzoguanamine compound, a methylol group-containing urea compound, a methylol group-containing glycoluryl compound, or a methylol group-containing phenol compound; (ii) compounds containing an alkoxyalkyl group, such as an alkoxyalkyl group-containing melamine compound, an alkoxyalkyl group-containing benzoguanamine compound, an alkoxyalkyl group-containing urea compound, an alkoxyalkyl group-containing glycoluryl compound, or an alkoxyalkyl group-containing phenol compound; (iii) compounds containing a carboxymethyl group, such as a carboxymethyl group-containing melamine compound, a carboxymethyl group-containing benzoguanamine compound, a carboxymethyl group-containing urea compound, a carboxymethyl group-containing glycoluryl compound, or a carboxymethyl group-containing phenol compound; (iv) Examples of epoxy compounds include bisphenol A-based epoxy compounds, bisphenol F-based epoxy compounds, bisphenol S-based epoxy compounds, novolak resin-based epoxy compounds, resol resin-based epoxy compounds, poly(hydroxystyrene)-based epoxy compounds, etc.

[0179] As an acid crosslinking agent, a compound having a phenolic hydroxyl group and a compound and resin imparting crosslinkability by introducing the crosslinking group into the acidic functional groups in the alkali-soluble resin may be used. In that case, the introduction rate of the crosslinking group is not particularly limited, but is preferably 5 to 100 mol% with respect to the total acidic functional groups in the compound having a phenolic hydroxyl group and the alkali-soluble resin, more preferably 10 to 60 mol%, and even more preferably 15 to 40 mol%. Within the above range, the crosslinking reaction occurs sufficiently, and a decrease in the residual film rate, swelling of the pattern, or meandering can be avoided, which is desirable.

[0180] In the lithography sublayer forming composition of the present invention, the acid crosslinking agent is preferably at least one selected from an alkoxyalkylated urea compound or its resin, or an alkoxyalkylated glycoluryl compound or its resin (acid crosslinking agent (1)), a phenol derivative having 1 to 6 benzene rings in the molecule, having 2 or more hydroxyalkyl groups or alkoxyalkyl groups in the entire molecule, wherein the hydroxyalkyl groups or alkoxyalkyl groups are bonded to any one of the benzene rings (acid crosslinking agent (2)), and a compound having at least one α-hydroxyisopropyl group (acid crosslinking agent (3)). For example, the compound disclosed in International Publication No. 2017 / 033943 may be cited.

[0181] In the lithography sublayer forming composition of the present invention, the content of the acid crosslinking agent is preferably 0.5 to 49 mass%, more preferably 0.5 to 40 mass%, even more preferably 1 to 30 mass%, and even more preferably 2 to 20 mass% with respect to the total mass of the solid component (component excluding the solvent). It is preferable that the content of the acid crosslinking agent be 0.5 mass% or more, as this improves the inhibitory effect on the solubility of the resist film with respect to the alkaline developer, thereby preventing a decrease in the residual film rate or the occurrence of swelling or meandering of the pattern. Additionally, it is preferable that the content be 49 mass% or less, as this prevents a decrease in the heat resistance of the resist.

[0182] In addition, the content of each acid crosslinking agent (1), acid crosslinking agent (2), and acid crosslinking agent (3) in the acid crosslinking agent is not particularly limited and can be selected depending on the type of substrate used when forming the resist pattern.

[0183] [Lithography Sublayer]

[0184] Since the polymer contained in the lithography underlayer forming composition of the present invention has high solubility in solvents and excellent film-forming properties, it is preferable to form a lithography underlayer using the lithography underlayer forming composition. For this reason, the rectangularity of the pattern is excellent. In addition, because the film-forming properties are excellent, a good resist pattern shape can be imparted. Furthermore, the lithography underlayer forming composition can form a lithography underlayer with high flatness.

[0185] That is, the lithography lower layer of the present invention is a lithography lower layer formed from the lithography lower layer forming composition. The lithography lower layer of the present invention can be suitably used as a lower layer (resist lower layer) of a photoresist (upper layer) used in a multilayer resist method.

[0186] As long as the lithography sublayer of the present invention is formed from the lithography sublayer forming composition, the method of formation is not particularly limited, and known methods may be applied. For example, the lithography sublayer can be formed by applying the lithography sublayer forming composition onto a substrate using a known coating method or printing method, such as spin coating or screen printing, and then removing the organic solvent.

[0187] It can also be suitably used in a multilayer resist method in which an additional resist sublayer is provided between an upper layer resist (photoresist, etc.) and a hard mask or an organic sublayer. In such a multilayer resist method, for example, an organic sublayer or a hard mask on a substrate is interposed therein, and a resist sublayer is formed thereon by a coating method, etc., and an upper layer resist (for example, photoresist, electron beam resist, EUV resist) is formed on the resist sublayer. Then, a resist pattern is formed by exposure and development, and the resist sublayer is dry-etched using the resist pattern to transfer the pattern, and the pattern is transferred by etching the organic sublayer, and the substrate is processed using the organic sublayer.

[0188] That is, the lithography lower layer (resist lower layer) of the present invention formed using the above-described lithography lower layer forming composition is unlikely to cause intermixing with the upper resist, also possesses heat resistance, and can obtain a rectangular and good pattern. The position of the resist lower layer formed using the lithography lower layer forming composition of the present invention (how many layers it is stacked in) is not particularly limited and may be immediately below the upper resist, may be the layer located closest to the substrate, or may be a sun inserted as the resist lower layer.

[0189] In forming fine patterns, the thickness of the resist film tends to be thin to prevent pattern collapse. Due to the thinning of the resist, dry etching to transfer a pattern to a film existing in the lower layer cannot transfer the pattern unless the etching speed is higher than that of the upper layer film. An organic lower layer film can be interposed on a substrate, the surface thereon can be coated with the lithography lower layer film of the present invention, and the surface thereon can be coated again with a resist film (organic resist film).

[0190] For example, using a pattern-transferred resist underlayer, the organic underlayer of the underlayer can be dry-etched with an oxygen-based gas to transfer the pattern to the organic underlayer, and then the pattern-transferred organic underlayer can be used to process the substrate using a halogen-containing gas.

[0191] Furthermore, since the lithographic sublayer of the present invention has high heat resistance, it can be used even under high-temperature baking conditions. Moreover, due to its relatively low molecular weight and low viscosity, it is easy to uniformly fill every corner of a substrate with steps (especially fine spaces or hole patterns), and as a result, planarity and filling characteristics tend to be relatively advantageously higher.

[0192] As a more specific method for forming a lithographic sublayer, a method for forming a lithographic sublayer according to the method described in the “process of forming a sublayer” in the pattern forming method described later is preferred.

[0193] [Resist pattern formation method (resist pattern formation method using a lithography underlayer forming composition)]

[0194] As the above-described lithography sublayer forming composition is excellent as a material for forming a lithography sublayer, it is preferable to form a resist pattern by a resist pattern forming method having a process of forming a lithography sublayer using the above-described lithography sublayer forming composition on a substrate.

[0195] That is, the pattern forming method of the present invention is a resist pattern forming method using a lithography underlayer forming composition.

[0196] A suitable pattern forming method of the present invention is, more specifically, a resist pattern forming method comprising: a process of forming a lower layer precursor on a substrate using the lithography lower layer forming composition and heating the lower layer precursor to 300°C or higher to form a lower layer; a process of forming at least one photoresist layer on the lower layer; and a process of irradiating the photoresist layer with radiation and performing development.

[0197] Process of forming the lower layer

[0198] The process of forming a lower layer film is a process of forming a lower layer film precursor on a substrate using the lithography lower layer film forming composition, and heating the lower layer film precursor to 300°C or higher to form a lower layer film.

[0199] The substrate used in this process may be a semiconductor substrate. As the semiconductor substrate, a silicon substrate may generally be used, but is not particularly limited, and may be made of a material different from the workpiece layer, such as Si, amorphous silicon (α-Si), p-Si, SiO2, SiN, SiON, W, TiN, Al, etc.

[0200] When using a semiconductor substrate, a metal film, a metal carbide film, a metal oxide film, a metal nitride film, a metal oxide carbide film, or a metal oxide nitride film may be formed as a workpiece layer (workpiece portion) on the semiconductor substrate. Examples of workpiece layers containing such metal include Si, SiO2, SiN, SiON, SiOC, p-Si, α-Si, TiN, WSi, BPSG, SOG, Cr, CrO, CrON, MoSi, W, W-Si, Al, Cu, Al-Si, etc., as well as various low dielectric films and their etching stopper films, and can typically be formed with a thickness of 50 to 10,000 nm, particularly 100 to 5,000 nm.

[0201] The present process is a process for forming a lower layer on a substrate using the above-described lithography lower layer forming composition. Before forming the lower layer using the above-described lithography lower layer forming composition, an organic lower layer or an organic hard mask may be formed on the substrate. Among these, the organic lower layer may be formed using a spin coating method or the like from a coating-type organic lower layer material, and the organic hard mask may be formed using a CVD method from an organic hard mask material having carbon as its main component. The types of such organic lower layers and organic hard masks are not particularly limited, but when the upper layer resist film forms a pattern by exposure, it is desirable to exhibit a sufficient anti-reflective film function. By forming such an organic lower layer or organic hard mask, the pattern formed by the upper layer resist film can be transferred onto the substrate (workpiece) without causing a difference in size conversion. Meanwhile, a "hard mask having carbon as the main component" refers to a hard mask in which 50 mass% or more of the solid content is composed of carbon-based materials such as amorphous hydride carbon, also known as amorphous carbon and represented as aC:H. The aC:H film can be deposited by various techniques, and plasma-enhanced chemical vapor deposition (PECVD) is widely used for cost efficiency and the ability to adjust film quality. As an example of the above hard mask, one may refer to the one described in Japanese Patent Publication No. 2013-526783.

[0202] When forming an organic lower layer on a substrate, the process is to form an organic lower layer on the substrate, form a lower layer precursor on the organic lower layer using the lithography lower layer forming composition, and form a lower layer by heating the lower layer precursor to 300°C or higher.

[0203] In addition, when forming an organic hard mask on a substrate, the process involves forming an organic hard mask on the substrate, forming a lower layer precursor on the organic hard mask using the lithography lower layer forming composition, and heating the lower layer precursor to 300°C or higher to form a lower layer.

[0204] As a method for forming a lower layer precursor using the above-mentioned lithography lower layer forming composition, it is preferable to form it on a substrate or on a workpiece provided with an organic lower layer, such as by a spin coating method.

[0205] When forming the lithography sublayer forming composition on a substrate or a workpiece using a spin coat method, the lithography sublayer forming composition is first applied to the substrate or the workpiece. At that time, the content of the polymer contained in the lithography sublayer forming composition can be appropriately adjusted by considering the spin coat rotation speed, rotation time, viscosity of the composition, and evaporation rate of the solvent. It is preferable that the content of the polymer contained in the lithography sublayer forming composition be 0.001 to 10 g per 100 mL of solvent contained in the lithography sublayer forming composition.

[0206] Next, a lower film precursor is formed by volatilizing and removing the organic solvent. It is preferable to adjust the film thickness of the lower film precursor to 1 to 200 nm by adjusting the content of the above-mentioned polymer, the number of spin coat rotations, the rotation time, etc.

[0207] Furthermore, when forming the lower layer film, it is preferable to perform a bake treatment heated to 300°C or higher to suppress the occurrence of mixing phenomena with the upper layer resist and to promote the crosslinking reaction. In this case, the bake temperature is preferably 300°C or higher, more preferably 300 to 450°C, and even more preferably 300 to 400°C. The bake time is not particularly limited, but is preferably 10 to 300 seconds. In this manner, the lower layer film is formed on the substrate. The thickness of the lower layer film can be appropriately selected according to the required performance and is not particularly limited, but is preferably 30 to 20,000 nm, and more preferably 50 to 15,000 nm.

[0208] Process of forming a photoresist layer

[0209] Next, a process for forming a photoresist layer is performed.

[0210] The process of forming a photoresist layer is a process of forming at least one photoresist layer on the lower film.

[0211] The present process is a process for forming a photoresist layer on a lower film. Examples of photoresist materials used in the photoresist layer include forming a positive pattern by dissolving the exposed area using an alkaline developer after forming a photoresist film and performing exposure, or forming a negative pattern by dissolving the unexposed area using an organic solvent developer.

[0212] In the case of forming a photoresist layer using a photoresist material, a wet process such as a spin coat method or screen printing is preferably used. In addition, after applying the photoresist material using a spin coat method or the like, a pre-bake is typically performed, and this pre-bake is preferably performed under conditions of a bake temperature of 80 to 180°C and a bake time of 10 to 300 seconds. Meanwhile, the thickness of the photoresist layer is not particularly limited, but generally, it is preferably 30 to 500 nm, and more preferably 50 to 400 nm.

[0213] The process of carrying out the phenomenon

[0214] Next, the process of performing the phenomenon is carried out.

[0215] The process of developing is a process of irradiating the photoresist layer with radiation and developing, and in this process, by performing exposure and developing as described above, a resist pattern can be obtained.

[0216] The radiation (exposure light) irradiated onto the photoresist layer can be appropriately selected and used depending on the photoresist material used. Generally, high-energy rays with a wavelength of 300 nm or less, specifically excimer lasers of 248 nm, 193 nm, and 157 nm, soft X-rays of 3 to 20 nm, electron beams, X-rays, etc., can be used.

[0217] As a method for forming a pattern, any one of the following methods may be appropriately used: lithography using light with a wavelength of 300 nm or less or EUV light; direct electron beam lithography; and inductive magnetic organization. By using such a method, fine patterns can be formed.

[0218] The development method can be appropriately selected depending on the photoresist material used as the raw material for the photoresist layer. When forming a positive type pattern, it is preferable to form a positive type pattern by dissolving the exposed area using an alkaline developer, and when forming a negative type pattern, it is preferable to form a negative type pattern by dissolving the unexposed area using a developer made of an organic solvent.

[0219] The resist pattern can be obtained as described above.

[0220] Furthermore, the pattern forming method of the present invention preferably includes a process of transferring a pattern to a lower layer film by etching using a resist pattern formed on an upper layer as described above as a mask, transferring a pattern to an organic lower layer film by etching using the resist lower layer film on which the pattern has been transferred as a mask, and additionally transferring a pattern to a substrate (workpiece) by etching using the organic lower layer film on which the pattern has been transferred as a mask.

[0221] Furthermore, as another aspect of the pattern forming method of the present invention, the pattern forming method of the present invention preferably includes a process of transferring a pattern to the lower layer film by etching using the resist pattern formed on the upper layer as described above as a mask, transferring a pattern to the organic hard mask by etching using the lower layer film on which the pattern has been transferred as a mask, and further transferring a pattern to the substrate (workpiece) by etching using the organic hard mask on which the pattern has been transferred as a mask.

[0222] [Positive-type resist composition (Second invention)]

[0223] The positive-type resist composition in the second invention of the present invention is a positive-type resist composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by the following formula (1B).

[0224] [Chemical Formula 11]

[0225]

[0226] (during food, X 1B is a hydrogen atom, a methyl group, or a halogen atom, and Y 1B is -O- or -NH-, ab is 0 or 1, and R B is a group having 2 to 30 carbon atoms containing an iodine atom.

[0227] Meanwhile, hereinafter, "the present invention" means "the first invention of the present invention," "the second invention of the present invention," or an invention comprising both "the first invention of the present invention" and "the second invention of the present invention."

[0228] That is, the positive-type resist composition of the present invention is a positive-type resist composition comprising a polymer, wherein the polymer is a polymer containing repeating units derived from an iodine-containing monomer represented by the formula (1B). Since the polymer containing repeating units derived from an iodine-containing monomer represented by the formula (1B) has excellent solvent solubility, heat resistance, and film-forming properties, and also has good developability with a developer such as an alkaline developer, it is excellent as a material for forming a lithography film, and is particularly excellent as a material for forming a resist film.

[0229] Polymer

[0230] The polymer included in the positive-type resist composition of the present invention is a polymer containing repeating units derived from an iodine-containing monomer represented by the following formula (1B). The polymer may be in a straight chain or a branched chain, preferably in a straight chain. In addition, the polymer may contain repeating units derived from one type of iodine-containing monomer alone, or may contain repeating units derived from two or more types of iodine-containing monomers.

[0231] By including the polymer in the positive type resist composition of the present invention, the resolution and etching resistance can be improved, and the resist sensitivity characteristics can also be improved.

[0232] [Chemical Formula 12]

[0233]

[0234] (during food, X 1B is a hydrogen atom, a methyl group, or a halogen atom, and Y 1B is -O- or -NH-, ab is 0 or 1, and R B is a group having 2 to 30 carbon atoms containing an iodine atom.

[0235] The reason why the positive type resist composition and resist film of the present invention have excellent resolution, etching resistance, and excellent resist sensitivity characteristics is not certain, but it is thought as follows.

[0236] It is believed that the resist film of the present invention, which contains an iodine-containing polymer, can improve the sensitivity of the resist because it can absorb irradiation light and supply secondary electrons or protons.

[0237] Furthermore, it is believed that by using a positive-type resist composition containing the above polymer as a resist film, the deterioration of the resist pattern shape is suppressed, and higher resolution becomes possible.

[0238] (Iodine-containing monomer represented by formula (1B))

[0239] The iodine-containing monomer used as a raw material for the above polymer is represented by the following formula (1B).

[0240] [Chemical Formula 13]

[0241]

[0242] (during food, X 1B is a hydrogen atom, a methyl group, or a halogen atom, and Y 1B is -O- or -NH-, ab is 0 or 1, and RB is a group having 2 to 30 carbon atoms containing an iodine atom.

[0243] In equation (1B), X 1B is a hydrogen atom, a methyl group, or a halogen atom, preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0244] X 1B When the atom is a hydrogen atom, a positive-type resist composition comprising a polymer using an iodine-containing monomer represented by formula (1B) as a raw material has excellent exposure sensitivity.

[0245] In equation (1B), Y 1B is -O- or -NH-, preferably -O-.

[0246] In formula (1B), ab is 0 or 1, preferably 1.

[0247] In equation (1B), R B is a group having 2 to 30 carbon atoms containing an iodine atom, preferably represented by the following formula (2B).

[0248] [Chemical Formula 14]

[0249]

[0250] (during food, L B is a directly bonded or divalent group having 1 to 24 carbon atoms, and R 1B Each is independently an alkyl group having 1 to 30 carbon atoms that may have substituents, an aryl group having 6 to 30 carbon atoms that may have substituents, an alkenyl group having 2 to 30 carbon atoms that may have substituents, an alkynyl group having 2 to 30 carbon atoms that may have substituents, an alkoxy group having 1 to 30 carbon atoms that may have substituents, a halogen atom other than iodine, a nitro group, an amino group, a carboxylic acid group, a crosslinking group, a dissociable group, a thiol group, or a hydroxyl group. bb is an integer from 1 to 5, cb is an integer from 0 to 4, and bb+cb is 1 to 5.)

[0251] In equation (2B), R 1B Each is independently an alkyl group having 1 to 30 carbon atoms that may have a substituent, an aryl group having 6 to 30 carbon atoms that may have a substituent, an alkenyl group having 2 to 30 carbon atoms that may have a substituent, an alkoxy group having 2 to 30 carbon atoms that may have a substituent, a halogen atom other than iodine, a nitro group, an amino group, a carboxylic acid group, a crosslinking group, a dissociable group, a thiol group, or a hydroxyl group.

[0252] bb is an integer from 1 to 5, preferably an integer from 1 to 3, more preferably 1 or 3, and even more preferably 3.

[0253] cb is an integer from 0 to 4, preferably 0.

[0254] bb+cb is 1 to 5, preferably 1 to 3, more preferably 1 or 3, and even more preferably 3.

[0255] L B is a directly bonded or divalent group having 1 to 24 carbon atoms. L B is preferably a direct bond. When a plurality of repeating units derived from an iodine-containing monomer represented by formula (1B) are contained in the polymer, L B Each may be the same or different, but preferably, they are the same. More preferably, all L B is a direct combination.

[0256] The divalent group having 1 to 24 carbon atoms may be an aliphatic or aromatic group, preferably an aliphatic group, and more preferably an alkylene group or a (poly)oxyalkylene group.

[0257] L B If α is an alkylene group, L B The number of carbon atoms is preferably 1 to 24, and more preferably 2 to 24.

[0258] LB If is a (poly)oxyalkylene group, L B The number of oxygen atoms in is preferably 1 to 12. L B The number of carbon atoms is preferably 1 to 24, and more preferably 2 to 24.

[0259] L B If is a (poly)oxyalkylene group, L B The group is preferably a (poly)oxyethylene group, a (poly)oxypropylene group, or a (poly)oxybutylene group, and more preferably a (poly)oxyethylene group.

[0260] A dissociable group refers to a group that dissociates under specific conditions, and includes acid dissociable groups that dissociate in the presence of acid, thermal dissociable groups that dissociate by heating, and photodissociable groups that dissociate by light irradiation, and acid dissociable groups are preferred. Specific examples of acid dissociable groups include those described in International Publication No. 2016 / 158168.

[0261] In addition, a crosslinking group refers to a group capable of crosslinking within or between molecules, and specific examples of crosslinking groups include those described in International Publication No. 2020 / 226150.

[0262] The group represented by formula (2B) is more preferably a group represented by the following formula (2aB), more preferably at least one selected from the group consisting of the group represented by the following formula (3B) and the group represented by the following formula (4B), and even more preferably a group represented by the following formula (3B). In particular, by selecting a monomer having the group represented by formula (3B), a polymer with excellent molecular weight controllability, solubility, and film-forming properties can be obtained.

[0263] [Chemical Formula 15]

[0264]

[0265] (In formula (2aB), L Bis a directly bonded or divalent group having 1 to 24 carbon atoms. bb is an integer from 1 to 5. In formula (3B), L B is a directly bonded or divalent group having 1 to 24 carbon atoms. In formula (4B), L B is a directly bonded or divalent group having 1 to 24 carbon atoms.

[0266] In formula (2aB), bb is an integer from 1 to 5, preferably an integer from 1 to 3, more preferably 1 or 3, and even more preferably 3. In particular, by selecting a monomer having a triiodophenyl group where bb is 3, a polymer with excellent molecular weight controllability, solubility, and film-forming properties can be obtained. When bb is 3, L B The triiodophenyl group bonded to is preferably a 2,3,5-triiodophenyl group or a 2,4,6-triiodophenyl group, and more preferably a 2,4,6-triiodophenyl group.

[0267] L in equations (2aB), (3B), and (4B) B is a directly bonded or divalent group having 1 to 24 carbon atoms. L B Either one is preferably a direct connection.

[0268] In the case where a polymer contains multiple repeating units derived from iodine-containing monomers represented by formulas (2aB), (3B), and (4B), L in formulas (2aB), (3B), and (4B). B Each may be the same or different, but preferably, they are the same. More preferably, all L B is a direct combination.

[0269] The above divalent group having 1 to 24 carbon atoms may be an aliphatic group or an aromatic group, preferably an aliphatic group, and more preferably an alkylene group or a (poly)oxyalkylene group.

[0270] L B If α is an alkylene group, L BThe number of carbon atoms is preferably 1 to 24, and more preferably 2 to 24.

[0271] L B If is a (poly)oxyalkylene group, L B The number of oxygen atoms in is preferably 1 to 12. L B The number of carbon atoms is preferably 1 to 24, and more preferably 2 to 24.

[0272] L B If is a (poly)oxyalkylene group, L B The group is preferably a (poly)oxyethylene group, a (poly)oxypropylene group, or a (poly)oxybutylene group, and more preferably a (poly)oxyethylene group.

[0273] (Other monomers)

[0274] As a raw material for the above polymer, other monomers other than the iodine-containing monomer represented by formula (1B) may be used. That is, the positive-type resist composition of the present invention may be a positive-type resist composition comprising a polymer containing repeating units derived from the iodine-containing monomer represented by formula (1B) and repeating units derived from other monomers other than the iodine-containing monomer represented by formula (1B). Meanwhile, the above polymer may contain only one type of repeating unit derived from other monomers, or may contain two or more types of repeating units derived from other monomers.

[0275] The polymer contained in the positive-type resist composition of the present invention is a polymer containing repeating units derived from an iodine-containing monomer represented by formula (1B), preferably a polymer additionally containing repeating units derived from a phenolic hydroxyl group-containing monomer. By additionally containing repeating units derived from a phenolic hydroxyl group-containing monomer, adhesion to the substrate is improved and film formation is improved.

[0276] Examples of monomers containing phenolic hydroxyl groups include 4-vinylphenol, 4-hydroxyphenyl(meth)acrylate, 4-hydroxyphenyl(meth)acrylamide, etc., and preferably 4-vinylphenol. Meanwhile, since phenolic hydroxyl groups may affect the polymerization reaction, it is desirable to introduce repeating units derived from monomers containing phenolic hydroxyl groups by protecting them during polymerization and deprotecting them after polymerization.

[0277] Protecting groups that protect phenolic hydroxyl groups include benzyl groups, methoxymethyl groups, trialkylsilyl groups, acyl groups, benzoyl groups, trityl groups, etc., preferably methoxymethyl groups, trialkylsilyl groups, acyl groups, benzoyl groups, trityl groups, more preferably methoxymethyl groups and acyl groups.

[0278] For example, when introducing repeating units derived from 4-vinylphenol into a polymer, 4-vinylphenyl acetate is polymerized as a raw material and deprotected by hydrolysis to introduce repeating units derived from 4-vinylphenol into the polymer.

[0279] The polymer included in the positive-type resist composition of the present invention is a polymer containing repeating units derived from an iodine-containing monomer represented by formula (1B), preferably a polymer additionally containing repeating units derived from an adamantane-structure-containing monomer. By additionally containing repeating units derived from an adamantane-structure-containing monomer, it becomes easy to decompose by acid and improves developability, thereby enabling the formation of fine patterns.

[0280] Examples of monomers containing the adamantane structure include adamantane-1-yl(meth)acrylate, 2-methyladamantan-2-yl(meth)acrylate, 2-ethyladamantan-2-yl(meth)acrylate, N-(1-adamanthyl)(meth)acrylamide, and preferably at least one selected from the group consisting of adamantane-1-yl(meth)acrylate, 2-methyladamantan-2-yl(meth)acrylate, and 2-ethyladamantan-2-yl(meth)acrylate, and more preferably 2-methyladamantan-2-yl(meth)acrylate.

[0281] Other monomers other than those listed above include (meth)acrylate monomers, styrene monomers, (meth)acrylamide monomers, nitrile group-containing vinyl monomers, vinyl halides, vinylidene halides, vinyl acetate, etc., and preferably (meth)acrylate monomers.

[0282] Examples of styrene-based monomers include styrene, p-methylstyrene, α-methylstyrene, styrene halides, vinyl benzoic acid, 4-vinylbenzenesulfonic acid, 4-vinylbenzenesulfonic acid esters, and 4-vinylbenzenesulfonamide.

[0283] Examples of (meth)acrylamide-based monomers include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, etc.

[0284] Examples of vinyl monomers containing nitrile groups include (meth)acrylonitrile.

[0285] Examples of (meth)acrylate-based monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, glycidyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, Nt-butylaminoethyl (meth)acrylate, polyalkylene glycol (meth)acrylate, etc., and preferably 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate. It is at least one selected from the group consisting of (meth)acrylate hydroxybutyl, (meth)acrylate glycidyl, and polyalkylene glycol (meth)acrylate, more preferably at least one selected from the group consisting of (meth)acrylate 2-hydroxyethyl, (meth)acrylate glycidyl, and polyethylene glycol (meth)acrylate, even more preferably at least one selected from the group consisting of (meth)acrylate 2-hydroxyethyl and polyalkylene glycol (meth)acrylate, and even more preferably polyalkylene glycol (meth)acrylate.

[0286] The polyalkylene glycol (meth)acrylate is preferably at least one selected from the group consisting of polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, and polybutylene glycol (meth)acrylate, more preferably at least one selected from the group consisting of polyethylene glycol (meth)acrylate and polypropylene glycol (meth)acrylate, and even more preferably polyethylene glycol (meth)acrylate.

[0287] (Molecular weight control agent)

[0288] A molecular weight control agent may be used as a raw material for the above polymer. The above polymer may contain only one type of structure derived from the molecular weight control agent, or may contain two or more types of structures derived from the molecular weight control agent.

[0289] The above molecular weight control agent refers to an additive capable of controlling the molecular weight range by inhibiting polymerization, and is typically a chain transfer agent. It is preferable that the molecular weight control agent be an aromatic compound. Examples of molecular weight control agents include various chain transfer agents, RAFT agents, NMP agents, ATRP agents, and TERP agents, and sulfur-containing chain transfer agents such as thiol-type chain transfer agents and RAFT agents are preferred. These may be used individually or in combination of two or more types.

[0290] The thiol-type chain transfer agent may be a monothiol compound, a dithiol compound, a trithiol compound, or a polythiol compound of tetrathiol or more, and it is preferable that it be a monothiol compound or a dithiol compound. The thiol-type chain transfer agent may be a thiol compound having a sulfur atom in addition to a thiol group. The thiol compound may be a molecule composed only of carbon, hydrogen, and sulfur.

[0291] Specific examples of thiol-type chain transfer agents include aliphatic monothiol compounds, aliphatic polythiol compounds, aliphatic thiols containing a sulfur atom other than a mercapto group, aromatic monothiol compounds, aromatic polythiols, aromatic polythiol compounds containing a sulfur atom other than a mercapto group, heterocyclic compounds containing a sulfur atom other than a mercapto group, compounds containing a hydroxyl group other than a mercapto group, and derivatives thereof. An aromatic monothiol compound or an aromatic polythiol compound containing a sulfur atom other than a mercapto group is preferred, and bis(4-mercaptophenyl)sulfide (4,4'-thiobisbenzenethiol) and 4-mercaptopyridine are more preferred. These may be used alone or in combination of two or more types.

[0292] Aliphatic monothiol compounds include methanethiol, ethanethiol, propanethiol, butanethiol, cyclohexanediol, etc.

[0293] Aliphatic polythiol compounds include methanedithiol, 1,2-ethanedithiol, 1,1-propanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 2,2-propanedithiol, 1,6-hexanedithil, 1,2,3-propanetrithiol, 1,1-cyclohexanedithil, 1,2-cyclohexanedithil, 2,2-dimethylpropane-1,3-dithiol, 3,4-dimethoxybutane-1,2-dithiol, 2-methylcyclohexane-2,3-dithiol, 1,1-bis(mercaptomethyl)cyclohexane, bis(2-mercaptoethyl ester) thiosaganate, and 2,3-dimercapto-1-propanol (2-mercaptoacetate). Examples include 2,3-dimercapto-1-propanol (3-mercaptopropionate), diethylene glycol bis(2-mercaptoacetate), diethylene glycol bis(3-mercaptopropionate), 1,2-dimercaptopropylmethyl ether, 2,3-dimercaptopropylmethyl ether, 2,2-bis(mercaptomethyl)-1,3-propanedithiol, bis(2-mercaptoethyl) ether, ethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(3-mercaptopropionate), trimethylolpropane bis(2-mercaptoacetate), trimethylolpropane bis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), tetrakis(mercaptomethyl)methane, etc.

[0294] Aliphatic thiols containing a sulfur atom other than a mercapto group include bis(mercaptomethyl)sulfide, bis(mercaptoethyl)sulfide, bis(mercaptopropyl)sulfide, bis(mercaptomethylthio)methane, bis(2-mercaptoethylthio)methane, bis(3-mercaptopropyl)methane, 1,2-bis(mercaptomethylthio)ethane, 1,2-(2-mercaptoethylthio)ethane, 1,2-(3-mercaptopropyl)ethane, 1,3-bis(mercaptomethylthio)propane, 1,3-bis(2-mercaptoethylthio)propane, 1,3-bis(3-mercaptopropylthio)propane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 2-mercaptoethylthio-1,3-propanedithiol, 1,2,3-Tris(mercaptomethylthio)propane, 1,2,3-Tris(2-mercaptoethylthio)propane, 1,2,3-Tris(3-mercaptopropylthio)propane, Tetrakis(mercaptomethylthiomethyl)methane, Tetrakis(2-mercaptoethylthiomethyl)methane, Tetrakis(3-mercaptopropylthiomethyl)methane, Bis(2,3-dimercaptopropyl)sulfide, 2,5-dimercapto-1,4-dithiane, Bis(mercaptomethyl)disulfide, Bis(mercaptoethyl)disulfide, Bis(mercaptopropyl)disulfide, 4-mercaptomethyl-3,6-dithioctan-1,8-dithiol, Bis(mercaptomethyl)-3,6,9-trithi-1,11-undecanedithiol, Bis(1,3-dimercapto-2-propyl)sulfide, hydroxymethylsulfidebis(2-mercaptoacetate), hydroxymethylsulfidebis(3-mercaptopropionate), hydroxyethylsulfidebis(2-mercaptoacetate), hydroxyethylsulfidebis(3-mercaptopropionate), hydroxypropylsulfidebis(2-mercaptoacetate), hydroxypropylsulfidebis(3-mercaptopropionate), hydroxymethyldisulfidebis(2-mercaptoacetate), hydroxymethyldisulfidebis(3-mercaptopropionate), hydroxyethyldisulfidebis(2-mercaptoacetate), hydroxyethyldisulfidebis(3-mercaptopropionate), hydroxypropyldisulfidebis(2-mercaptoacetate), Hydroxypropyldisulfidebis(3-mercaptopropionate),2-Mercaptoethyl etherbis(2-mercaptoacetate), 2-Mercaptoethyl etherbis(3-mercaptopropionate), 1,4-Dithian-2,5-Diolbis(2-mercaptoacetate), 1,4-Dithian-2,5-Diolbis(3-mercaptopropionate), thioglycolate bis(2-mercaptoethyl ester), thiodipropionicate bis(2-mercaptoethyl ester), 4,4'-thiodibutyricate bis(2-mercaptoethyl ester), dithiodiglycolate bis(2-mercaptoethyl ester), dithiodipropionicate bis(2-mercaptoethyl ester), 4,4'-dithiodibutyricate bis(2-mercaptoethyl ester), thiodiglycolate bis(2,3-dimercaptopropyl ester), Examples include bis(2,3-dimercaptopropyl ester) of thiodipropionic acid, bis(2,3-dimercaptopropyl ester) of dithiodiglylic acid, and dithiodipropionic acid (2,3-dimercaptopropyl ester).

[0295] Examples of aromatic monothiol compounds include benzenethiol, o-methyl-α-toluenthiol, o-toluenthiol, m-toluenthiol, p-toluenthiol, 1-naphthalenethiol, 2-naphthalenethiol, 4-mercaptopyridine, etc., and 4-mercaptopyridine is preferred.

[0296] Aromatic polythiols include 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, 1,2-bis(mercaptoethyl)benzene, 1,3-bis(mercaptoethyl)benzene, 1,4-bis(mercaptoethyl)benzene, 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3-tris(mercaptomethyl)benzene, 1,2,4-tris(mercaptomethyl)benzene, 1,3,5-tris(mercaptomethyl)benzene, Examples include 1,2,3-tris(mercaptoethyl)benzene, 1,2,4-tris(mercaptoethyl)benzene, 1,3,5-tris(mercaptoethyl)benzene, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,3-di(p-methoxyphenyl)propane-2,2-dithiol, 1,3-diphenylpropane-2,2-dithiol, phenylmethane-1,1-dithiol, and 2,4-di(p-mercaptophenyl)pentane.

[0297] Aromatic polythiol compounds containing sulfur atoms other than mercapto groups include 1,2-bis(mercaptomethylenethio)benzene, 1,3-bis(mercaptomethylenethio)benzene, 1,4-bis(mercaptomethylenethio)benzene, 1,2-bis(mercaptomethylenethio)benzene, 1,3-bis(mercaptomethylenethio)benzene, 1,4-bis(mercaptomethylenethio)benzene, 1,2-bis(mercaptompropylenethio)benzene, 1,3-bis(mercaptompropylenethio)benzene, 1,4-bis(mercaptompropylenethio)benzene, 1,2-bis(mercaptomethylenethiomethylene)benzene, 1,3-bis(mercaptomethylenethiomethylene)benzene, 1,4-bis(mercaptomethylenethiomethylene)benzene, 1,2-Bis(mercaptopropylenethiomethylene)benzene, 1,3-Bis(mercaptopropylenethiomethylene)benzene, 1,4-Bis(mercaptopropylenethiomethylene)benzene, Bis(4-mercaptophenyl)sulfide(4,4'-thiobisbenzenethiol), Bis(3-mercaptophenyl)sulfide, 4,4'-oxybisbenzenethiol, 4,4'-biphenyldithiol, 1,2-Bis(mercaptomethyleneoxy)benzene, 1,3-Bis(mercaptomethyleneoxy)benzene, 1,4-Bis(mercaptomethyleneoxy)benzene, 1,2-Bis(mercaptoethyleneoxy)benzene, 1,3-Bis(mercaptomethyleneoxy)benzene, 1,4-Bis(mercaptomethyleneoxy)benzene, 1,2-Bis(mercaptomethyleneoxy)benzene, Examples include 1,3-bis(mercaptoethyleneoxymethylene)benzene, 1,4-bis(mercaptoethyleneoxymethylene)benzene, 1,2-bis(mercaptopropyleneoxymethylene)benzene, 1,3-bis(mercaptopropyleneoxymethylene)benzene, 1,4-bis(mercaptopropyleneoxymethylene)benzene, 1,3,5-trimercaptobenzene, 1,2,3-tris(mercaptomethylthio)benzene, 1,2,4-tris(mercaptomethylthio)benzene, 1,3,5-tris(mercaptomethylthio)benzene, 1,2,3-tris(mercaptoethylthio)benzene, 1,2,4-tris(mercaptoethylthio)benzene, 1,3,5-tris(mercaptoethylthio)benzene, etc. Bis(4-mercaptophenyl)sulfide (4,4'-thiobisbenzenethiol) is preferred.

[0298] Examples of heterocyclic compounds containing sulfur atoms other than mercapto groups include 3,4-thiopendithiol and 2,5-dimercapto-1,3,4-thiadiazole.

[0299] Compounds containing a hydroxyl group other than a mercapto group include 2-mercaptoethanol, 3-mercapto-1,2-propanediol, glycerin di(mercaptoacetate), 1-hydroxy-4-mercaptocyclohexane, 2,4-dimercaptophenol, 2-mercaptohydroquinone, 4-mercaptophenol, 3,4-dimercapto-2-propanol, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1,2-dimercapto-1,3-butanediol, pentaerythritol tris(3-mercaptopropionate), pentaerythritol mono(3-mercaptopropionate), pentaerythritol bis(3-mercaptopropionate), pentaerythritol tris(thioglycolate), Examples include dipentaerythritol pentakis(3-mercaptopropionate), hydroxymethyl-tris(mercaptoethylthiomethyl)methane, 1-hydroxyethylthio-3-mercaptoethylthiobenzene, etc.

[0300] Specific examples of RAFT agents include dithioesters, trithiocarbonates, dithiocarbamates, and disulfides. These may be used individually or in combination of two or more types.

[0301] Examples of dithioesters include 2-cyano-2-propylbenzodithioate and 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid.

[0302] Examples of trithiocarbonates include 2-cyano-2-propyldodecyl trithiocarbonate, 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid, 2-(dodecylthiocarbonothioilthio)-2-methylpropionic acid, cyanomethyldodecyl trithiocarbonate, etc.

[0303] Examples of dithiocarbamates include cyanomethylmethyl(phenyl)carbamodithioate.

[0304] Examples of disulfides include bis(thiobenzoyl)disulfide and bis(dodecylsulfanylthiocarbonyl)disulfide.

[0305] (Composition of polymer)

[0306] The content of repeating units derived from the iodine-containing monomer represented by formula (1B) is preferably 1 to 100 mass%, more preferably 3 to 70 mass%, even more preferably 5 to 50 mass%, even more preferably 7 to 40 mass%, even more preferably 8 to 35 mass%, even more preferably 10 to 30 mass%, and even more preferably 15 to 25 mass% in the polymer. By setting the content of repeating units derived from the iodine-containing monomer represented by formula (1B) to the above range, the resolution and etching resistance of the positive-type resist composition can be improved, and the resist sensitivity characteristics can be improved, along with solvent solubility, heat resistance, and film formation properties.

[0307] When the above polymer contains repeating units derived from a monomer containing phenolic hydroxyl groups, the content of repeating units derived from the monomer containing phenolic hydroxyl groups is preferably 1 to 80 mass% in the polymer, more preferably 5 to 70 mass%, even more preferably 10 to 65 mass%, even more preferably 20 to 60 mass%, even more preferably 30 to 55 mass%, and even more preferably 40 to 50 mass%.

[0308] When the above polymer contains repeating units derived from a phenolic hydroxyl group-containing monomer, the molar ratio [phenolic hydroxyl group-containing monomer / iodine-containing monomer] of the repeating units derived from the phenolic hydroxyl group-containing monomer to the repeating units derived from the iodine-containing monomer represented by formula (1B) is preferably 20 / 80 to 95 / 5, more preferably 30 / 70 to 90 / 10, even more preferably 40 / 60 to 90 / 10, even more preferably 50 / 50 to 85 / 15, even more preferably 60 / 40 to 80 / 20, and even more preferably 65 / 35 to 75 / 25. By setting the content of repeating units derived from the phenolic hydroxyl group-containing monomer to the above range, adhesion to the substrate is improved and film formation is improved.

[0309] When the above polymer contains repeating units derived from a monomer containing an adamantane structure, the content of the repeating units derived from the monomer containing an adamantane structure is preferably 1 to 80 mass%, more preferably 3 to 70 mass%, even more preferably 5 to 60 mass%, even more preferably 10 to 50 mass%, even more preferably 20 to 45 mass%, and even more preferably 30 to 40 mass% of the above polymer.

[0310] When the above polymer contains repeating units derived from a monomer containing an adamantane structure, the molar ratio [adamantane structure-containing monomer / iodine-containing monomer] of the repeating units derived from the adamantane structure-containing monomer to the repeating units derived from the iodine-containing monomer represented by formula (1B) is preferably 20 / 80 to 99 / 1, more preferably 30 / 70 to 90 / 10, even more preferably 40 / 60 to 85 / 15, even more preferably 50 / 50 to 80 / 20, even more preferably 55 / 45 to 75 / 25, and even more preferably 60 / 40 to 70 / 30. By setting the content of repeating units derived from the monomer containing an adamantane structure to the above range, it becomes easy to decompose by acid and improves developmentability, thereby enabling the formation of fine patterns.

[0311] When the above polymer contains a structure derived from a molecular weight control agent, the content of the structure derived from the molecular weight control agent is preferably 1 to 80 mass%, more preferably 3 to 60 mass%, even more preferably 5 to 50 mass%, even more preferably 6 to 30 mass%, even more preferably 8 to 20 mass%, and even more preferably 10 to 20 mass% of the above polymer.

[0312] (Molecular weight of the polymer)

[0313] The number average molecular weight of the polymer is preferably 500 to 100,000, more preferably 1,000 to 50,000, even more preferably 2,000 to 50,000, even more preferably 3,000 to 40,000, even more preferably 5,000 to 35,000, even more preferably 10,000 to 30,000, and even more preferably 20,000 to 30,000. By having the number average molecular weight of the polymer within the above range, the solubility and film-forming properties of the polymer are excellent. The number average molecular weight is the molecular weight converted to polystyrene.

[0314] The molecular weight distribution (Mw / Mn) of the above polymer is preferably 1.3 to 7.5, more preferably 1.5 to 7.0, even more preferably 2.0 to 6.0, even more preferably 2.5 to 5.0, and even more preferably 3.0 to 4.0.

[0315] Method for manufacturing polymers

[0316] The polymer included in the positive-type resist composition of the present invention is a polymer containing repeating units derived from an iodine-containing monomer represented by formula (1B). While there are no restrictions on the method of preparation, it is preferable to follow the method below.

[0317] The above polymer can be obtained by a process of polymerizing the above monomer, which is a raw material. The above process may be a process of polymerizing the monomer in the presence of a molecular weight control agent. By polymerizing the monomer in the presence of a molecular weight control agent, the molecular weight can be controlled, and the obtained polymer can be made to have a target molecular weight.

[0318] The polymerization method in the above process is not particularly limited. Examples of polymerization methods include bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., and preferably, solution polymerization.

[0319] In addition, polymerization methods include radical polymerization, anionic polymerization, and cationic polymerization, and preferably radical polymerization. A suitable polymerization method can be selected depending on the type of monomer, polymerization temperature, etc.

[0320] In the polymerization process described above, it is preferable to use a polymerization initiator.

[0321] The polymerization initiator can be selected based on the type of monomer, polymerization temperature, etc.

[0322] Examples of polymerization initiators include azo-based initiators and peroxide-based initiators, and preferably, azo-based initiators.

[0323] Examples of azo-based initiators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,2-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2-amidinopropane)dihydrochloride, etc., and 2,2'-azobis(isobutyronitrile) is preferred.

[0324] Examples of peroxide-based initiators include benzoyl peroxide, di-t-butyl hydroperoxide, t-butyl hydroperoxide, cumyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, benzoyl peroxide, dicumyl peroxide, ethyl 3,3-di(t-amylperoxy)butyrate, potassium sulfate, ammonium persulfate, etc.

[0325] Polymerization initiators may be used alone or in combination of two or more types.

[0326] The amount of polymerization initiator used can be appropriately changed depending on the type of monomer or the type of polymerization initiator, and with respect to the total amount of monomer, it is preferably 0.1 to 50 mol%, more preferably 0.5 to 30 mol%, even more preferably 1 to 20 mol%, even more preferably 2 to 10 mol%, and even more preferably 3 to 7 mol%.

[0327] When polymerization in the above process is carried out as solution polymerization, it is preferable to select a suitable solvent considering the solubility of the monomer or polymerization initiator and the polymerization temperature, and to carry out the polymerization in that solvent. A preferred solvent is one in which the obtained polymer dissolves.

[0328] Examples of solvents used for polymerization include N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone, acetone, THF, benzene, toluene, ethylbenzene, xylene, chlorobenzene, methyl ethyl ketone, ethyl lactic acid, isopropyl alcohol, etc. These may be used individually or in combination of two or more types. Among these, amide-based solvents are more preferably used, and even more preferably N,N-dimethylformamide.

[0329] The amount of monomer used as a raw material can be adjusted to obtain a polymer of the desired composition. Specifically, it is preferable to use the following amounts.

[0330] The amount of iodine-containing monomer represented by formula (1B) used is preferably 1 to 100 mass%, more preferably 3 to 70 mass%, even more preferably 5 to 50 mass%, even more preferably 7 to 40 mass%, even more preferably 8 to 35 mass%, even more preferably 10 to 30 mass%, and even more preferably 15 to 25 mass% with respect to the total amount of monomer and molecular weight control agent. By setting the amount of iodine-containing monomer represented by formula (1B) to the above range, the resist sensitivity characteristics of the positive-type resist composition can be improved, along with solvent solubility, heat resistance, and film formation properties.

[0331] When the monomer used as a raw material contains a monomer containing phenolic hydroxyl groups, the amount of the monomer containing phenolic hydroxyl groups used is preferably 1 to 80 mass%, more preferably 5 to 70 mass%, even more preferably 10 to 65 mass%, even more preferably 20 to 60 mass%, even more preferably 30 to 55 mass%, and even more preferably 40 to 50 mass% with respect to the total amount of the monomer and the molecular weight control agent.

[0332] When the raw material monomer contains a monomer containing phenolic hydroxyl groups, the molar ratio of the monomer containing phenolic hydroxyl groups to the iodine-containing monomer represented by formula (1B) [monomer containing phenolic hydroxyl groups / monomer containing iodine] is preferably 20 / 80 to 95 / 5, more preferably 30 / 70 to 90 / 10, even more preferably 40 / 60 to 90 / 10, even more preferably 50 / 50 to 85 / 15, even more preferably 60 / 40 to 80 / 20, and even more preferably 65 / 35 to 75 / 25. By including the monomer containing phenolic hydroxyl groups in the above range, adhesion to the substrate is improved and film formation is improved. In addition, since phenolic hydroxyl groups may affect the polymerization reaction, it is preferable to use a monomer in which the phenolic hydroxyl groups are protected as the monomer containing phenolic hydroxyl groups.

[0333] Examples of protecting groups in monomers that protect phenolic hydroxyl groups include benzyl groups, methoxymethyl groups, trialkylsilyl groups, acyl groups, benzoyl groups, trityl groups, etc., preferably acyl groups, and more preferably acetyl groups. It is preferable to deprotect the protecting group after polymerization to introduce repeating units derived from the monomer containing phenolic hydroxyl groups.

[0334] When the raw material monomer contains an adamantane structure-containing monomer, the molar ratio of the adamantane structure-containing monomer to the iodine-containing monomer represented by formula (1B) [adamantane structure-containing monomer / iodine-containing monomer] is preferably 20 / 80 to 99 / 1, more preferably 30 / 70 to 90 / 10, even more preferably 40 / 60 to 85 / 15, even more preferably 50 / 50 to 80 / 20, even more preferably 55 / 45 to 75 / 25, and even more preferably 60 / 40 to 70 / 30. By including the adamantane structure-containing monomer in the above range, it is easy to decompose by acid and the developability is improved, so that fine pattern formation becomes possible.

[0335] When a molecular weight control agent is used as a raw material, the amount of the molecular weight control agent used is preferably 1 to 80 mass% with respect to the total amount of monomer and molecular weight control agent, more preferably 3 to 60 mass%, even more preferably 5 to 50 mass%, even more preferably 6 to 30 mass%, even more preferably 8 to 20 mass%, and even more preferably 10 to 20 mass%.

[0336] The reaction temperature can be appropriately adjusted according to the temperature at which the polymerization initiator used decomposes, preferably 0 to 100°C, more preferably 20 to 80°C, even more preferably 30 to 70°C, even more preferably 40 to 70°C, and even more preferably 50 to 70°C.

[0337] The reaction time can be appropriately adjusted according to the reaction temperature, amount of catalyst, reactivity of the raw material, desired molecular weight, etc., preferably 1 to 72 hours, more preferably 5 to 60 hours, even more preferably 12 to 50 hours, even more preferably 15 to 40 hours, and even more preferably 15 to 30 hours.

[0338] If the polymer after polymerization has protecting groups, it is desirable to perform a deprotection process. The deprotection process can be performed by treating according to the type of protecting group, and known methods may be applied.

[0339] For example, when using a monomer in which the phenolic hydroxyl group of a monomer containing a phenolic hydroxyl group is protected by an acyl group, it is desirable to deprotect the acyl group by hydrolysis to impart a phenolic hydroxyl group to the polymer.

[0340] It is preferable to purify the obtained polymer by conventional post-treatment. Specifically, it is preferable to remove raw materials or by-products by introducing the reaction mixture into an organic solvent in which the polymer does not dissolve and recovering the target polymer as a precipitate. Additionally, it is preferable to remove catalysts, etc., by dissolving the polymer in an organic solvent in which it dissolves and washing it with water or the like.

[0341] At the end of the reaction or purification process, if the polymer is obtained as a solution dissolved in an organic solvent, it is preferable to concentrate and dry it to obtain a polymer as a solid.

[0342] The polymer obtained as described above has high solubility in solvents, excellent film formation properties, and excellent resist sensitivity characteristics.

[0343] <Composition of Positive-Type Resist Composition>

[0344] The positive-type resist composition of the present invention is a composition for forming a lithography film comprising the polymer described above. That is, the positive-type resist composition of the present invention is a composition for forming a lithography film comprising a polymer containing repeating units derived from an iodine-containing monomer represented by formula (1B).

[0345] The positive-type resist composition of the present invention comprises the above-mentioned polymer, which has excellent solvent solubility, heat resistance, and film-forming properties, and is suitable as a composition for forming a resist film in that it has excellent resist sensitivity characteristics. That is, the positive-type resist composition of the present invention is preferably a composition for forming a resist film.

[0346] <Solvent>

[0347] The positive-type resist composition of the present invention may be appropriately adjusted according to its use, provided that it includes the polymer, and preferably additionally includes a solvent as a component other than the polymer.

[0348] The solvent is not particularly limited, but may include ethylene glycol monoalkyl ether acetates, ethylene glycol monoalkyl ethers, propylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ethers, lactic acid esters, aliphatic carboxylic acid esters, esters other than the above esters, aromatic hydrocarbons, ketones, amides, lactones, and ethers, and preferably at least one selected from the group consisting of propylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ethers, lactic acid esters, aliphatic carboxylic acid esters, ketones, and ethers, and more preferably at least one selected from the group consisting of propylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ethers, and ketones.

[0349] Examples of ethylene glycol monoalkyl ether acetates include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, ethylene glycol mono-n-butyl ether acetate, etc.

[0350] Examples of ethylene glycol monoalkyl ethers include ethylene glycol monomethyl ether and ethylene glycol monoethyl ether.

[0351] Examples of propylene glycol monoalkyl ether acetates include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate (PGMEA), propylene glycol mono-n-propyl ether acetate, propylene glycol mono-n-butyl ether acetate, and preferably propylene glycol monoethyl ether acetate (PGMEA).

[0352] Examples of propylene glycol monoalkyl ethers include propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether, and preferably propylene glycol monomethyl ether (PGME).

[0353] Examples of lactic acid esters include methyl lactic acid, ethyl lactic acid, n-propyl lactic acid, n-butyl lactic acid, n-amyl lactic acid, etc., and preferably ethyl lactic acid.

[0354] Examples of aliphatic carboxylic acid esters include methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, n-amyl acetate, n-hexyl acetate, methyl propionate, ethyl propionate, etc., and preferably butyl acetate and ethyl propionate.

[0355] Examples of esters other than the above esters include 3-methyl methoxypropionate, 3-ethyl methoxypropionate, 3-methyl ethoxypropionate, 3-ethyl ethoxypropionate, 3-methyl-2-methylpropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methoxy-3-methylpropionate butyl, 3-methoxy-3-methylbutyrate butyl, methyl acetoacetate, methyl pyruvate, ethyl pyruvate, 2-methyl isobutyrate (HBM), etc.

[0356] Examples of aromatic hydrocarbons include toluene and xylene.

[0357] Examples of ketones include methyl ethyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclopentanone (CPN), cyclohexanone (CHN), etc., and preferably 2-heptanone, cyclopentanone (CPN), and cyclohexanone (CHN).

[0358] Examples of amides include N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.

[0359] Examples of lactones include γ-lactones.

[0360] Anisole is preferred as an ether. As for the solvent, one type may be used alone, or two or more types may be used in combination.

[0361] The above solvent is preferably a safe solvent. The above solvent is preferably at least one selected from the group consisting of propylene glycol monoethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclopentanone (CPN), cyclohexanone (CHN), 2-heptanone, anisole, butyl acetate, ethyl propionate, and ethyl lactic acid, and more preferably at least one selected from the group consisting of propylene glycol monoethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and cyclohexanone (CHN).

[0362] The solvent content is preferably 20 to 99 mass% with respect to the total amount of the positive-type resist composition, more preferably 50 to 99 mass%, even more preferably 60 to 98 mass%, and even more preferably 90 to 98 mass%.

[0363] Other ingredients

[0364] The positive-type resist composition of the present invention may be formulated by appropriately adjusting the composition according to the application, provided that it contains the polymer mentioned above. It may also contain components other than the polymer and components other than the solvent. Meanwhile, the following components are solid components and are typically dissolved in a solvent and formulated in the positive-type resist composition.

[0365] Other components contained in the positive-type resist composition of the present invention may additionally include at least one selected from the group consisting of an acid generating agent, a crosslinking agent, an acid diffusion control agent, and other additives, preferably additionally include at least one selected from the group consisting of an acid generating agent, a crosslinking agent, and an acid diffusion control agent, more preferably additionally include at least one selected from the group consisting of an acid generating agent and a crosslinking agent, and even more preferably additionally include an acid generating agent and a crosslinking agent.

[0366] The content of the polymer contained in the positive-type resist composition of the present invention is preferably 50 to 99.4 mass% with respect to the total content of the solid components (the sum of the contents of the polymer, acid generator, crosslinking agent, acid diffusion control agent, and other additives), more preferably 60 to 95 mass%, even more preferably 70 to 90 mass%, and even more preferably 70 to 85 mass%. Within this range, the resolution can be improved and the line edge roughness (LER) can be reduced.

[0367] (Acid generator)

[0368] The positive-type resist composition of the present invention may additionally contain an acid-generating agent, and preferably additionally contains an acid-generating agent.

[0369] It is preferable that the acid generator be an acid generator that generates acid directly or indirectly by irradiation with any one of visible light, ultraviolet light, excimer laser, electron beam, extreme ultraviolet (EUV), X-ray, and ion beam.

[0370] As for radiation, ultraviolet rays such as g-rays and i-rays may be used, and using an excimer laser is preferable as it enables micro-processing. In addition, as high-energy rays, electron beams, extreme ultraviolet rays, X-rays, or ion beams are also preferable as they enable micro-processing.

[0371] Examples of acid-generating agents include compounds disclosed in International Publication No. 2017 / 033943.

[0372] The acid generator is preferably an acid generator having an aromatic ring, and more preferably an acid generator having a sulfonate ion having an aryl group. The acid generator is more preferably at least one selected from the group consisting of diphenyltrimethylphenylsulfonium p-toluenesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoromethanesulfonate, ditertiarybutyldiphenyliodonium nonafluorobutanesulfonate, and pyridinium paratoluenesulfonic acid. By using the acid generator, line edge roughness can be reduced.

[0373] The acid generator may preferably additionally contain a diazonaphthoquinone photoactive compound.

[0374] The diazonaphthoquinone photoactive compound is not particularly limited as long as it is used as a photosensitive component in a positive-type resist composition.

[0375] The diazonapthoquinone photoactive compound is preferably a polymeric diazonapthoquinone photoactive compound or a nonpolymeric diazonapthoquinone photoactive compound, more preferably a nonpolymeric diazonapthoquinone photoactive compound, even more preferably a nonpolymeric diazonapthoquinone photoactive compound with a molecular weight of 1,500 or less, even more preferably a nonpolymeric diazonapthoquinone photoactive compound with a molecular weight of 1,200 or less, and even more preferably a nonpolymeric diazonapthoquinone photoactive compound with a molecular weight of 1,000 or less. As a specific example of the diazonapthoquinone photoactive compound, the nonpolymeric diazonapthoquinone photoactive compound disclosed in International Publication No. 2016 / 158881 may be cited. The diazonapthoquinone photoactive compound may be used alone or in combination of two or more types.

[0376] The content of the acid generator contained in the positive-type resist composition of the present invention is preferably 0.001 to 49 mass% with respect to the total content of the solid components (the sum of the contents of the polymer, acid generator, crosslinking agent, acid diffusion control agent, and other additives), more preferably 1 to 40 mass%, even more preferably 3 to 30 mass%, and even more preferably 10 to 25 mass%. Within this range, sensitivity can be increased and the edge roughness of the pattern profile can be reduced. The acid generator may be used alone or in combination of two or more types.

[0377] (Crosslinking agent)

[0378] The positive-type resist composition of the present invention may additionally contain a crosslinking agent, and preferably additionally contains a crosslinking agent.

[0379] The crosslinking agent contained in the positive-type resist composition of the present invention is preferably an acid crosslinking agent. The acid crosslinking agent can crosslink the polymer intramolecularly or intermolecularly by an acid generated from an acid-generating agent. By including a crosslinking agent, the strength of the pattern can be increased.

[0380] The acid crosslinking agent is preferably a compound having a crosslinkable group.

[0381] The crosslinking groups are not particularly limited, but may include hydroxyalkyl groups, carbonyl groups, nitrogen-containing groups, glycidyl-containing groups, aromatic groups, polymerizable multiple bond-containing groups, and groups derived therefrom, preferably hydroxyalkyl groups and groups derived therefrom.

[0382] Specifically, the hydroxyalkyl group and the group derived therefrom may include the hydroxyalkyl group, alkoxyalkyl group, acetoxyalkyl group, etc., preferably at least one selected from the group consisting of the hydroxyalkyl group and the alkoxyalkyl group, and more preferably an alkoxymethyl group.

[0383] Examples of carbonyl groups and groups derived therefrom include formyl groups, carboxyalkyl groups, etc.

[0384] Examples of nitrogen-containing groups include dimethylaminomethyl groups, diethylaminomethyl groups, dimethylolaminomethyl groups, diethylolaminomethyl groups, morpholinomethyl groups, etc.

[0385] Examples of glycidyl-containing groups include glycidyl ether groups, glycidyl ester groups, glycidyl amino groups, etc.

[0386] Examples of aromatic groups include benzyloxymethyl, benzoyloxymethyl, allyloxyalkyl, and aralkyloxyalkyl groups.

[0387] Examples of polymerizable multiple bond-containing groups include vinyl groups and isopropene groups.

[0388] Next, suitable examples of acid crosslinking agents are presented by classification. Meanwhile, the type and content of the acid crosslinking agent can be adjusted according to the type of substrate used when forming the resist pattern, etc.

[0389] Acid crosslinking agents, preferably, may include methylol group-containing compounds, alkoxyalkyl group-containing compounds, carboxymethyl group-containing compounds, epoxy compounds, etc.

[0390] Examples of methylol group-containing compounds include methylol group-containing melamine compounds, methylol group-containing benzoguanamine compounds, methylol group-containing urea compounds, methylol group-containing glycoluryl compounds, methylol group-containing phenol compounds, etc.

[0391] Examples of compounds containing alkoxyalkyl groups include alkoxyalkyl group-containing melamine compounds, alkoxyalkyl group-containing benzoguanamine compounds, alkoxyalkyl group-containing urea compounds, alkoxyalkyl group-containing glycoluryl compounds, alkoxyalkyl group-containing phenol compounds, etc.

[0392] Examples of carboxymethyl group-containing compounds include carboxymethyl group-containing melamine compounds, carboxymethyl group-containing benzoguanamine compounds, carboxymethyl group-containing urea compounds, carboxymethyl group-containing glycoluryl compounds, and carboxymethyl group-containing phenol compounds.

[0393] Examples of epoxy compounds include bisphenol A-based epoxy compounds, bisphenol F-based epoxy compounds, bisphenol S-based epoxy compounds, novolak resin-based epoxy compounds, resol resin-based epoxy compounds, and poly(hydroxystyrene)-based epoxy compounds.

[0394] Furthermore, acid crosslinking agents may include compounds in which crosslinking properties are imparted by introducing the crosslinking group to acidic functional groups in compounds having phenolic hydroxyl groups, and resins in which crosslinking properties are imparted by introducing the crosslinking group to acidic functional groups in alkali-soluble resins.

[0395] The introduction rate of crosslinking groups is preferably 0 to 80 mol% with respect to all acidic functional groups in the compound having phenolic hydroxyl groups and the alkali-soluble resin, more preferably 0 to 60 mol%, and even more preferably 0 to 40 mol%. Within the above range, the crosslinking reaction occurs at an appropriate rate, and it is desirable to avoid a decrease in the residual film rate, swelling of the pattern, or meandering.

[0396] Acid crosslinking agents may further include alkoxyalkylated urea compounds or their resins, alkoxyalkylated glycoluryl compounds or their resins, phenol derivatives, and compounds having an α-hydroxyisopropyl group. Examples of these compounds or resins include, for instance, the compounds disclosed in International Publication No. 2017 / 033943.

[0397] The above phenol derivative is a phenol derivative having 1 to 6 benzene rings in the molecule, having 2 or more hydroxyalkyl groups or alkoxyalkyl groups in the entire molecule, and having the hydroxyalkyl groups or alkoxyalkyl groups bonded to any one of the benzene rings.

[0398] The content of the crosslinking agent contained in the positive-type resist composition of the present invention is preferably 0 to 49 mass% with respect to the total content of the solid components (the sum of the contents of the polymer, acid generator, crosslinking agent, acid diffusion control agent, and other additives), more preferably 0 to 40 mass%, even more preferably 0 to 30 mass%, and even more preferably 0 to 20 mass%. Within the above range, dissolution of the resist film in the developer can be suppressed, a reduction in the residual film rate or swelling and meandering of the resist pattern can be suppressed, and furthermore, heat resistance as a resist can be improved, which is desirable.

[0399] (Acid diffusion control agent)

[0400] The positive-type resist composition of the present invention may further contain an acid diffusion control agent, and preferably further contains an acid diffusion control agent.

[0401] An acid diffusion control agent optionally contained in the positive-type resist composition of the present invention controls the diffusion of acid generated from an acid generator by radiation within the resist film, thereby preventing undesirable chemical reactions in unexposed regions. Consequently, the storage stability of the positive-type resist composition is improved, and the resolution can be enhanced. Furthermore, changes in the linewidth of the resist pattern due to variations in the installation time before and after radiation irradiation can be suppressed, resulting in excellent process stability.

[0402] Examples of acid diffusion control agents include radiodegradable basic compounds such as basic compounds containing nitrogen atoms, basic sulfonium compounds, and basic iodine compounds. Examples of acid diffusion control agents include compounds disclosed in International Publication No. 2017 / 033943. Acid diffusion control agents may be used alone or in combination of two or more types.

[0403] The content of the acid diffusion control agent contained in the positive-type resist composition of the present invention is preferably 0.001 to 49 mass% with respect to the total content of the solid components (the total content of each of the polymer, acid generator, crosslinking agent, acid diffusion control agent, and other additives), more preferably 0.01 to 10 mass%, even more preferably 0.01 to 5 mass%, and even more preferably 0.01 to 3 mass% from the perspective of preventing deterioration of sensitivity, developability of unexposed areas, etc. Within the above range, deterioration of resolution or deterioration of the shape and dimensional fidelity of the resist pattern can be suppressed. Furthermore, the shape of the upper layer of the resist pattern does not deteriorate when the waiting time from electron beam irradiation to heating after radiation irradiation is long.

[0404] (Other additives)

[0405] The positive-type resist composition of the present invention may additionally contain other additives to the extent that the effects of the present invention are not impaired.

[0406] Other additives may include solubility promoters, solubility control agents, sensitizers, surfactants, and organic carboxylic acids or phosphoric oxo acids or derivatives thereof. Other additives may include compounds disclosed in International Publication No. 2017 / 033943.

[0407] The total content of other additives contained in the positive-type resist composition of the present invention is preferably 0 to 49 mass% with respect to the total content of the solid components (the sum of the contents of each of the polymer, acid generating agent, crosslinking agent, acid diffusion control agent, and other additives), more preferably 0 to 5 mass%, even more preferably 0 to 1 mass%, and even more preferably 0 mass%, and it is even more preferable not to include them.

[0408] Method for preparing a positive-type resist composition

[0409] The method for preparing the positive-type resist composition of the present invention is not particularly limited, but preferably, it is a method of dissolving the above components in a solvent to form a homogeneous solution. If necessary, the solution obtained above may be filtered to remove impurities. The filter used for filtration is preferably a filter with a pore diameter of about 0.2 μm.

[0410] The positive-type resist composition of the present invention may contain a resin to a extent that does not impair the effects of the present invention.

[0411] Examples of resins include novolak resin, polyvinylphenols, polyacrylic acid, polyvinyl alcohol, styrene-maleic anhydride resin, etc.

[0412] The total content of the resin contained in the positive-type resist composition of the present invention is preferably 30 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and even more preferably 0 parts by mass or not, with respect to 100 parts by mass of the polymer.

[0413] [Resist film]

[0414] The resist film of the present invention is a resist film formed from the positive-type resist composition.

[0415] As described above, the positive-type resist composition is a positive-type resist composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by formula (1B), so it has excellent resolution and etching resistance, and excellent resist sensitivity characteristics, making it an excellent raw material for forming a resist film.

[0416] The resist film of the present invention can be formed from a positive type resist composition by the method described in the method for forming a resist pattern described below.

[0417] The resist film of the present invention can be obtained as an amorphous film by known methods such as spin coating. Depending on the type of developer used, a positive type resist pattern can be formed.

[0418] When a positive-type resist pattern is used, the dissolution rate of the amorphous film formed by spin-coating the positive-type resist composition with respect to the developer at 23°C is preferably 5 Å / sec or less, and more preferably 0.0005 to 5 Å / sec. If the dissolution rate is within the above range, the resist can be made insoluble in the developer, and resolution can be improved. This is presumed to be because the contrast at the interface between the exposed area that dissolves in the developer and the unexposed area that does not dissolve in the developer increases due to the change in solubility before and after exposure of the polymer containing repeating units derived from the iodine-containing monomer represented by formula (1B). In addition, there is an effect of reducing line edge roughness and reducing defects.

[0419] When a positive-type resist pattern is formed, the dissolution rate of the portion of the amorphous film formed by spin-coating the positive-type resist composition exposed to radiation such as an excimer laser (preferably a KrF excimer laser), extreme ultraviolet rays, electron beams, or X-rays at 23°C with respect to the developer is preferably 10 Å / sec or more. If the dissolution rate is within the above range, it is suitable for the resist and the resolution is improved. This is presumed to be because the micro-surface portion of the polymer containing repeating units derived from the iodine-containing monomer represented by formula (1B) is dissolved, thereby reducing line edge roughness. In addition, there is a defect reduction effect.

[0420] [Method for forming a resist pattern]

[0421] The method for forming a resist pattern according to the present invention is a method for forming a resist pattern using the positive type resist composition on a substrate.

[0422] More specifically, the method for forming a resist pattern comprises a process of forming a resist film on a substrate using the positive-type resist composition, and a process of exposing the resist film to light and developing it. The formed resist pattern may be an upper layer resist in a multilayer process.

[0423] Process of forming a resist film

[0424] The method for forming a resist pattern according to the present invention includes a process of forming a resist film on a substrate using the positive-type resist composition.

[0425] A method for forming a resist film may include applying the positive-type resist composition onto a substrate using a coating means such as rotary coating, flexible coating, or roll coating.

[0426] The substrate may be a conventionally known substrate, and may be a substrate for electronic components or one on which a wiring pattern is formed.

[0427] Examples of substrates include silicon wafers, metal substrates such as copper, chrome, iron, and aluminum, and glass substrates.

[0428] Materials for wiring patterns include copper, aluminum, nickel, gold, etc.

[0429] In addition, an inorganic film or an organic film may be provided on the substrate. Examples of inorganic films include inorganic anti-reflective films (inorganic BARC). Examples of organic films include organic anti-reflective films (organic BARC). The substrate may be surface-treated with hexamethyldisilazane (1,1,1,3,3,3-Hexamethyldisilazane), etc.

[0430] The substrate coated with the above positive-type resist composition may also be heated. The heating conditions can be appropriately adjusted according to the components of the composition, preferably at 20 to 250°C, and more preferably at 20 to 150°C, as this improves the adhesion of the resist film to the substrate.

[0431] Photolithography process

[0432] The method for forming a resist pattern according to the present invention includes a process of exposing a formed resist film to light. By this process, the resist film is exposed to light in a desired pattern.

[0433] Exposure is performed using one type of radiation selected from the group consisting of visible light, ultraviolet light, excimer laser, electron beam, extreme ultraviolet light (EUV), X-ray, and ion beam. The exposure conditions can be appropriately adjusted according to the composition of the lithography film forming composition.

[0434] It is preferable to heat the substrate having the resist film after irradiation. The heating conditions can be appropriately adjusted according to the composition of the lithography film forming composition, preferably 20 to 250°C, and more preferably 20 to 150°C. By heating, a fine pattern of high precision in the exposure can be stably formed.

[0435] The process of carrying out the phenomenon

[0436] The method for forming a resist pattern according to the present invention includes a process of exposing a formed resist film to light and performing development. The process is a process of developing the exposed resist film with a developer. By the process, a desired resist pattern is formed.

[0437] The developer is preferably an alkaline aqueous solution. Depending on the type of developer, the resist pattern can be differentiated. Generally, a positive resist pattern is obtained using an alkaline aqueous solution.

[0438] As for the alkaline aqueous solution, an aqueous solution of tetramethylammonium hydroxide is preferred.

[0439] An example of a developed solution is that disclosed in International Publication No. 2017 / 033943.

[0440] The developer may contain a surfactant.

[0441] Examples of surfactants include nonionic surfactants and ionic surfactants, and preferably, nonionic surfactants.

[0442] In addition, the surfactant is preferably at least one selected from the group consisting of fluorine-based surfactants and silicone-based surfactants, and more preferably at least one selected from the group consisting of nonionic fluorine-based surfactants and nonionic silicone-based surfactants.

[0443] Examples of fluorinated surfactants and silicone surfactants include Japanese Patent Publication No. S62-36663, Japanese Patent Publication No. S61-226746, Japanese Patent Publication No. S61-226745, Japanese Patent Publication No. S62-170950, Japanese Patent Publication No. S63-34540, Japanese Patent Publication No. H7-230165, Japanese Patent Publication No. H8-62834, Japanese Patent Publication No. H9-54432, Japanese Patent Publication No. H9-5988, U.S. Patent No. 5405720, No. 5360692, No. 5529881, No. 5296330, No. 5436098, and Examples of surfactants described in Specification No. 5576143, Specification No. 5294511, and Specification No. 5824451 may be used.

[0444] The amount of surfactant used is preferably 0.001 to 5 mass% with respect to the total amount of the developer, more preferably 0.005 to 2 mass%, and even more preferably 0.01 to 0.5 mass%.

[0445] Development methods include the dip method, puddle method, spray method, and dynamic dispensing method.

[0446] The dip method is a method of immersing a substrate in a tank filled with developer for a certain period of time; the puddle method is a method of developing by lifting the developer onto the surface of the substrate by surface tension and stopping for a certain period of time; the spray method is a method of spraying the developer onto the surface of the substrate; and the dynamic dispensing method is a method of continuously dispensing the developer while scanning the developer dispensing nozzle at a certain speed onto a substrate rotating at a certain speed.

[0447] There is no specific limit to the time for performing the phenomenon, but it is preferably 10 to 90 seconds.

[0448] Other Processes

[0449] The method for forming a resist pattern of the present invention may include, in addition to each of the above processes, the following process.

[0450] After the process of performing the development, a process of stopping the development can be carried out by replacing it with another solvent.

[0451] After the process of developing, it is desirable to include a cleaning process using a rinse solution (rinsing process).

[0452] The rinsing liquid is preferably a solvent that does not dissolve the resist pattern, and more preferably a solution containing an organic solvent or water.

[0453] The rinse solution is preferably a hydrophilic organic solvent or water, and more preferably water.

[0454] Organic solvents can be mixed in multiple quantities.

[0455] Rinse solution may contain surfactants.

[0456] The vapor pressure of the rinse solution at 20°C is preferably 0.05 to 5 kPa, more preferably 0.1 to 5 kPa, and even more preferably 0.12 to 3 kPa. When the vapor pressure of the rinse solution is within the above range, the temperature uniformity within the wafer surface is further improved, and furthermore, swelling caused by the penetration of the rinse solution is further suppressed, thereby improving the dimensional uniformity within the wafer surface.

[0457] The cleaning method is preferably a spin coating method, a dip method, or a spray method, and more preferably a spin coating method. It is even more preferable to clean by the spin coating method and, after cleaning, to rotate the substrate at a rotational speed of 2000 rpm to 4000 rpm to remove the rinse liquid from the substrate.

[0458] The rotary coating method is a method of continuously dispensing rinse liquid onto a substrate rotating at a constant speed, the dip method is a method of immersing a substrate in a tank filled with rinse liquid for a certain period of time, and the spray method is a method of spraying rinse liquid onto the surface of a substrate.

[0459] There is no specific time limit for rinsing the pattern, but preferably it is 10 to 90 seconds.

[0460] After forming a resist pattern, a patterned wiring board is obtained by etching. The etching method can be performed using known methods such as dry etching using plasma gas, and wet etching using an alkaline solution, a cupric chloride solution, a ferric chloride solution, etc.

[0461] After forming the resist pattern, plating may be performed. The plating method is not particularly limited, but examples include copper plating, solder plating, nickel plating, gold plating, etc.

[0462] The remaining resist pattern after etching can be peeled off with an organic solvent. The organic solvent is not particularly limited, but examples include PGMEA (propylene glycol monomethyl ether acetate), PGME (propylene glycol monomethyl ether), ethyl sulfate, etc. The peeling method is not particularly limited, but examples include immersion methods and spray methods. In addition, the wiring board on which the resist pattern is formed may be a multilayer wiring board and may have small diameter through holes.

[0463] Wiring boards can also be formed by the lift-off method. The lift-off method is a process in which a resist pattern is formed, a metal is deposited in a vacuum, and then the resist pattern is dissolved in a solution.

[0464] Examples

[0465] The present invention will be described in detail based on the embodiments shown below, but the present invention is not limited by these embodiments.

[0466] [1] An example of a lithography underlayer forming composition (first invention)

[0467] [analyze]

[0468] Fourier transform infrared spectroscopy (FT-IR) spectra were measured using a JASCO FT / IR4200 (manufactured by Japan Spectroscopic Corporation).

[0469] 1 H NMR spectrum, 13 The 1C NMR spectrum was measured using FTECS-400K (manufactured by Nippon Electronics Co., Ltd.) under conditions of a frequency of 400 MHz, DMSO-d6 as the solvent, and Me4Si (TMS) as the internal standard.

[0470] The number-average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the polymer were measured by size exclusion chromatography (SEC) under the following conditions. Calibration was performed using standard polystyrene (narrow molecular weight distribution).

[0471] (Measurement conditions, Device: HLC-8220 SEC device, manufactured by Tosoh Corporation, Column: TSKgel Super AW3000, AW2500×2, Detector: RI, UV, Eluent: DMF (20mM) solution of LiBr and phosphoric acid, Flow rate: 0.6mL / min)

[0472] [evaluation]

[0473] Solubility

[0474] At 23°C, the polymers obtained in Preparation Examples 1A to 10A were dissolved in propylene glycol monomethyl ether acetate (PGMEA) and 1-methoxy-2-propanol (propylene glycol monomethyl ether, PGME) to form a 30 mass% solution for each.

[0475] Afterwards, the solubility after standing at -20℃ for 30 days was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1A.

[0476] (metewand)

[0477] A: It was confirmed visually that no precipitates had formed.

[0478] C: The occurrence of precipitates was confirmed visually.

[0479] Tabernacle City

[0480] The lithography underlayer forming composition obtained in the examples and comparative examples was applied onto a silicon wafer by spin coating and dried to form a resist film with a thickness of 10 nm.

[0481] Regarding the membrane properties, the formation of the above-mentioned resist film was classified as "good". The evaluation results are shown in Table 2A.

[0482] <EB 패턴 평가>

[0483] A lithography sublayer forming composition obtained in the example was applied onto a SiO2 substrate with a film thickness of 300 nm, and a sublayer with a film thickness of 70 nm was formed by baking at 150°C for 60 seconds and then at 400°C for 120 seconds. An ArF resist solution was applied onto this sublayer, and a photoresist layer with a film thickness of 140 nm was formed by baking at 130°C for 60 seconds.

[0484] Meanwhile, as for the ArF resist solution, a compound represented by the following formula (5) was prepared by combining 5 parts by mass, triphenylsulfonium nonafluorobutanesulfonate: 1 part by mass, tributylamine: 2 parts by mass, and PGMEA: 92 parts by mass.

[0485] In addition, the compound represented by the following formula (5) was obtained as follows. 4.15 g of 2-methyl-2-methacryloyloxyadamantan, 3.00 g of methacryloyloxy-γ-butyrolactone, 2.08 g of 3-hydroxy-1-adamantyl methacrylate, and 0.38 g of 2,2'-azobis(isobutyronitrile) were dissolved in 80 mL of tetrahydrofuran to form a reaction solution. This reaction solution was polymerized for 22 hours under a nitrogen atmosphere while maintaining the reaction temperature at 63°C, after which the reaction solution was added dropwise into 400 mL of n-hexane. The resulting resin obtained in this manner was coagulated and purified, the resulting white powder was filtered, and dried overnight at 40°C under reduced pressure to obtain the compound represented by formula (5). The numbers in formula (5) represent the ratio of each constituent unit.

[0486] [Chemical Formula 16]

[0487]

[0488] Next, a photoresist layer was exposed using an electron beam lithography device (ELIONIX; ELS-7500, 50 keV), baked (PEB) at 115°C for 90 seconds, and developed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 seconds to obtain a positive type resist pattern.

[0489] Table 3A shows the results of observing defects in the obtained resist patterns of 55 nmL / S (1:1) and 80 nmL / S (1:1) with respect to the resist pattern shape after development. In the table, "Good" indicates that no major defects were observed in the resist patterns formed at line widths of 55 nmL / S (1:1) and 80 nmL / S (1:1) with respect to the resist pattern shape after development, and "Poor" indicates that major defects were observed in the resist pattern formed at either line width. Additionally, "Resolution" in the table is the minimum line width with no pattern collapse and good rectangularity, and "Sensitivity" indicates the minimum amount of electron beam energy capable of drawing a good pattern shape.

[0490] Meanwhile, as a comparative example, the resolution, sensitivity, and resist pattern shape were evaluated in the same manner as in the above example without forming a lower layer. Comparative Example 3 was prepared in the same manner as the example, except that a lower layer was not formed, by directly forming a photoresist layer on a SiO2 substrate and obtaining a positive type resist pattern.

[0491] <EUV 노광 평가>

[0492] (EUV Sensitivity Evaluation)

[0493] The lithography sublayer forming composition obtained in the examples and comparative examples was spin-coated onto a silicon wafer, and then baked at 110°C for 60 seconds to form a photoresist layer with a thickness of 100 nm. Subsequently, an extreme ultraviolet (EUV) exposure apparatus “EUVES-7000” (product name, manufactured by Risotec Japan Co., Ltd.) was used at 1 mJ / cm² 2 From 1 mJ / cm² 2 80 mJ / cm² 2After performing maskless shot exposure with the exposure amount increased to [value], the wafer was baked (PEB) at 110°C for 90 seconds and developed in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 seconds to obtain a wafer with 80 shots of shot exposure. For each obtained shot exposure area, the film thickness was measured using an optical interference film thickness meter "VM3200" (product name, manufactured by SCREEN Semiconductor Solutions Co., Ltd.), and profile data of the film thickness against the exposure amount was acquired. The exposure amount at which the slope of the variation in film thickness against the exposure amount is greatest was [defined as] the sensitivity value (mJ / cm²). 2 It was calculated as ) and used as an indicator of EUV sensitivity. EUV sensitivity was evaluated according to the following criteria. A lower sensitivity value is desirable because it indicates better EUV sensitivity. A lower sensitivity value is desirable because it increases the ability to supply secondary electrons or protons to the resist, especially when used as a sublayer. The evaluation results are shown in Table 4A.

[0494] (metewand)

[0495] A: 30mJ / cm 2 under

[0496] B: 30mJ / cm 2 40 mJ / cm² or more 2 under

[0497] C: 40mJ / cm 2 more

[0498] [raw material]

[0499] The raw materials used in the examples and their abbreviations are as follows.

[0500] 2,4,6-Triiodophenol (TIP) (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

[0501] Acryloyl chloride (AC) (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0502] 4-Mercaptopyridine (MP) (Manufactured by Tokyo Chemical Industry Co., Ltd.)

[0503] 4,4'-Thiobisbenzenethiol (TBBT) (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

[0504] 2-(2-ethoxyethoxy)ethyl acrylate (EEA) (Manufactured by Tokyo Kasei Kogyo Co., Ltd. Dryed with calcium hydride and purified by distillation.)

[0505] 2-Hydroxyethyl acrylate (HEA) (Manufactured by Tokyo Kasei Kogyo Co., Ltd. Dryed with calcium hydride and purified by distillation.)

[0506] Glycidyl methacrylate (GMA) (Manufactured by Tokyo Kasei Kogyo Co., Ltd. Dryed with calcium hydride and purified by distillation.)

[0507] 2,2'-Azobis(isobutyronitrile) (AIBN) (Manufactured by Tokyo Kasei Kogyo Co., Ltd. Used by recrystallizing from ethyl acetate.)

[0508] N,N'-Dimethylformamide (DMF) (dried with calcium hydride and purified by distillation)

[0509] p-iodostyrene

[0510] [Synthesis of Iodine-Containing Monomers]

[0511] Synthesis Example 1A (Synthesis of 2,4,6-Triiodophenyl Acrylate (TIPA))

[0512] [Chemical Formula 17]

[0513]

[0514] 2,4,6-triiodophenol (TIP) (30 mmol, 14.4 g) and triethylamine (6 mL) were dissolved in tetrahydrofuran (60 mL) at 0°C to form a solution. Next, acryloyl chloride (AC) (45 mmol, 4.07 mL) was slowly added to this solution. Next, the resulting mixture was slowly brought to room temperature and stirred for 20 hours.

[0515] Subsequently, the solution was filtered, and the filtrate was concentrated using a rotary evaporator. Chloroform was added to the residue, and the resulting suspension was washed with 0.1N hydrochloric acid and a saturated sodium bicarbonate solution, and then separated to obtain the organic phase. The organic phase was dried with anhydrous magnesium sulfate and concentrated using a rotary evaporator. The residue was purified by silica gel column chromatography (eluent: chloroform / hexane (1 / 1)) to obtain a white powder. The white powder was dissolved in a chloroform / hexane mixture and recrystallized to obtain 2,4,6-triiodophenylacrylate (TIPA) as a colorless solid (quantity 12.6 g (yield 87%)). The analysis results are shown below.

[0516] FT-IR(KBr, cm -1 ): 3030(νC-H aromatic), 1730(νC=O ester), 1635, 1530 and 702(νC=C aromatic), 1137(νC-OC ether), 535(νI-C halobenzene).

[0517] 1 H-NMR (400MHz, DMSO-d6, TMS): δ(ppm)=6.26(d, J=10.4Hz, 1H, CH₂=), 6.45(dd, 1H, J=6.8Hz, =CH-), 6.62(d, J=17.6Hz, 1H, CH2=), 8.18(s, 1H, aromatic H).

[0518] 13 C-NMR (100MHz, DMSO-d6, TMS): δ(ppm)=162.08(C=O), 151.77(C=C of aromatic), 147.16(C=C of aromatic), 134.56(CH2=CH), 127.12(CH2=CH), 91.71(C=C of aromatic), 91.66(C=C of aromatic).

[0519] Elemental analysis (C9H5I3O2): (Calculated value) C20.56, H0.96, I72.40. (Measured value) C20.47, H1.05, I72.68.

[0520] [Manufacturing of Polymers]

[0521] Preparation Example 1A (Preparation of MP-poly(TIPA) (Chain transfer radical polymerization of 2,4,6-triiodophenylacrylate (TIPA) using 4-mercaptopyridine (MP) as a molecular weight control agent))

[0522] [Chemical Formula 18]

[0523]

[0524] 2,4,6-triiodophenylacrylate (TIPA) (1.0 mmol, 0.52 g), 4-mercaptopyridine (MP) (0.1 mmol, 0.11 g), 2,2'-azobis(isobutyronitrile) (AIBN) (3 mol% relative to TIPA, 5.0 mg), and N,N-dimethylformamide (DMF) (0.3 mL) were placed in a polymerization tube and sealed by freeze-drying. Subsequently, the reaction was carried out at 60°C for 20 hours. The resulting reaction mixture was diluted with tetrahydrofuran (THF) and added to methanol to obtain a white solid as a precipitate. The obtained solid was washed with methanol and dried under vacuum at 25°C for 24 hours to obtain MP-poly(TIPA) (yield 84%). The analysis results are shown below.

[0525] Mn=9,300, Mw / Mn=1.85.

[0526] FT-IR(KBr, cm -1 ): 2934(νC-H aliphatic), 1760(νC=O ester), 1537, 1419 and 832(νC=C aromatic), 1204(νC-OC, ether), 534(νI-C, halobenzene).

[0527] 1 H-NMR (400MHz, DMSO-d6, TMS): δ(ppm)=1.64-4.08(br, CH2and CH3in the polymer main chain), 7.57-8.56(br m, aromatic H).

[0528] Preparation Examples 2A~4A (Preparation of MP-poly(TIPA) (Chain transfer radical polymerization of 2,4,6-triiodophenylacrylate (TIPA) using 4-mercaptopyridine (MP) as a molecular weight control agent))

[0529] MP-poly(TIPA) was obtained in the same manner as Preparation Example 1A, except that the amount of 4-mercaptopyridine (MP) was changed to the ratio shown in Table 1A and the amount of 2,2'-azobis(isobutyronitrile) (AIBN) was equal to that of 4-mercaptopyridine (MP). The yield, number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) are shown in Table 1A.

[0530] Preparation Example 5A (poly(TIPA 85 -co-EEA 15 Preparation of ) (copolymerization of 2,4,6-triiodophenylacrylate (TIPA) and 2-(2-ethoxyethoxy)ethylacrylate (EEA))

[0531] [Chemical Formula 19]

[0532]

[0533] 2,4,6-triiodophenylacrylate (TIPA) (0.8 mmol, 0.42 g), 2,2'-azobis(isobutyronitrile) (AIBN) (3.0 mol%, 5.0 mg relative to the monomer amount (total amount of TIPA and EEA 1.0 mmol), 2-(2-ethoxyethoxy)ethylacrylate (EEA) (0.2 mmol, 38 mg), and N,N-dimethylformamide (DMF) (0.3 mL) were placed in a polymerization tube and sealed by freeze degassing. Subsequently, the reaction was carried out at 60°C for 20 hours. The resulting reaction mixture was diluted with tetrahydrofuran (THF) and added to methanol to obtain a white solid as a precipitate. The obtained solid was washed with methanol and dried under vacuum at 25°C for 24 hours to obtain poly(TIPA-co-EEA). (Yield 93%). The analysis results are shown below.

[0534] Mn=19,200, Mw / Mn=2.81.

[0535] FT-IR(KBr, cm -1 ): 2863(νC-H aliphatic), 1763(νC=O ester), 1539, 1420, and 862(νC=C aromatic), 1207(νC-OC ether), 536(νI-C halobenzene).

[0536] ¹H-NMR (400MHz, DMSO-d6, TMS): δ(ppm)=1.06(br s, -OCH3), 1.54-3.74(br, CH2and CH3in the polymer main chain), 4.03(br s, -OCH2-), 8.06(br s, aromatic H).

[0537] The polymer composition ratio is, 1 TIPA / EEA was calculated as 85 / 15 based on the integration ratio of 8.06 ppm of phenylproton in TIPA and 1.06 ppm of methylproton in EEA in H NMR.

[0538] Preparation Example 6A (poly(TIPA 77 -co-HEA 23 Preparation of ) (copolymerization of 2,4,6-triiodophenylacrylate (TIPA) and 2-hydroxyethylacrylate (HEA))

[0539] Poly(TIPA-co-HEA) was obtained in the same manner as in Preparation Example 5A, except that the type and amount of monomers were 2,4,6-triiodophenyl acrylate (TIPA) (0.80 mmol) and 2-hydroxyethyl acrylate (HEA) (0.20 mmol). (Yield 94%). The analysis results are shown below.

[0540] Mn=14,540, Mw / Mn=1.73.

[0541] The polymer composition ratio is, 1 TIPA / HEA was calculated as 77 / 23 based on the integration ratio of 8.07 ppm of phenylproton in TIPA and 4.55 ppm of hydroxyproton in H E NMR.

[0542] Preparation Example 7A (poly(TIPA 88 -co-HEA 12 Preparation of ) (copolymerization of 2,4,6-triiodophenylacrylate (TIPA) and 2-hydroxyethylacrylate (HEA))

[0543] Poly(TIPA-co-HEA) was obtained in the same manner as in Preparation Example 5A, except that the monomer amounts were 2,4,6-triiodophenyl acrylate (TIPA) (0.90 mmol) and 2-hydroxyethyl acrylate (HEA) (0.10 mmol). The polymer composition ratio, yield, number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) are shown in Table 1A.

[0544] Preparation Example 8A (poly(TIPA 70 -co-EEA 20 -co-GMA 10 Preparation of ) (copolymerization of 2,4,6-triiodophenylacrylate (TIPA), 2-(2-ethoxyethoxy)ethylacrylate (EEA), and glycidyl methacrylate (GMA))

[0545] [Chemical Formula 20]

[0546]

[0547] Poly(TIPA-co-HEA) was obtained in the same manner as in Preparation Example 5A, except that the types and amounts of monomers were 2,4,6-triiodophenyl acrylate (TIPA) (0.7 mmol), 2-(2-ethoxyethoxy)ethyl acrylate (EEA) (0.2 mmol), and glycidyl methacrylate (GMA) (0.1 mmol). Yield 89%. Analysis results are shown below.

[0548] Mn=24,500, Mw / Mn=3.58.

[0549] FT-IR(KBr, cm -1): 2923(νC-H aliphatic), 1764(νC=O ester), 1538, 1420, and 861(νC=C aromatic), 1108(νC-OC ether), 903(νepoxy), and 531(νI-Chalobenzene).

[0550] 1 H-NMR (400MHz, DMSO-d6, TMS): δ(ppm)=1.06(br s, -OCH3), 1.24-3.77(br, CH2and CH3in the polymer main chain), 4.01(br s, -OCH2-), 8.05(br s, aromatic H).

[0551] The polymer composition ratio is, 1 TIPA / EEA / GMA = 70 / 20 / 10 was calculated based on the integration ratio of 8.05 ppm of phenylproton in the TIPA portion, 1.06 ppm of methylproton in the EEA portion, and 4.01 ppm of methyleneproton in the GMA portion in 1H NMR.

[0552] Preparation Example 9A (Preparation of TBBT-poly(p-iodostyrene)(p-iodostyrene / TBBT=6 / 1 (molar ratio))) (Chain transfer radical polymerization of p-iodostyrene using 4,4'-thiobisbenzenethiol (TBBT) as a molecular weight control agent)

[0553] p-iodostyrene (0.345 g, 1.5 mmol), 4,4'-thiobisbenzenethiol (TBBT) (0.065 g, 0.25 mmol), 2,2'-azobis(isobutyronitrile) (AIBN) (0.082 g, 0.5 mmol), and N,N-dimethylformamide (DMF) (2.0 mL) were placed in a polymerization tube and sealed by freeze-drying. Subsequently, the reaction was carried out at 60°C for 20 hours. The resulting reaction mixture was added to water to obtain a white solid as a precipitate. The obtained solid was dried at 60°C for 12 hours to obtain TBBT-poly(p-iodostyrene) (yield approximately 90%).

[0554] Structural analysis is 1It was performed by H-NMR and IR spectra. The number average molecular weight was approximately 1800.

[0555] Preparation Example 10A (Preparation of TBBT-poly(p-iodostyrene)(p-iodostyrene / TBBT=12 / 1 (molar ratio))) (Chain transfer radical polymerization of p-iodostyrene using 4,4'-thiobisbenzenethiol (TBBT) as a molecular weight control agent)

[0556] TBBT-poly(p-iodostyrene) was obtained in the same manner as Preparation Example 9A, except that the amount of p-iodostyrene was 0.69 g and 3.0 mmol (yield of about 85%).

[0557] The number average molecular weight was about 4000.

[0558] [Preparation of a composition for forming a lithographic underlayer]

[0559] Examples 1A–29A and Comparative Examples 1A–2A

[0560] Lithography underlayer forming compositions were each prepared with the compositions shown in Table 2A.

[0561] In Table 2A, the numbers in parentheses indicate the content (mixing amount) (parts by mass) of each component. Also, the ratio of the solvent is a mass ratio.

[0562] As the polymer, the polymer obtained in Preparation Examples 1A to 10A was used in the examples, and the phenol novolak resin (manufactured by Gun-A Chemical Co., Ltd., product name: PSM4357) was used in the comparative examples.

[0563] The following were used for the acid generator, crosslinking agent, and organic solvent.

[0564] Using the obtained lithography underlayer forming composition, film formation evaluation, EB pattern evaluation, and EUV exposure evaluation were performed. The results are shown in Tables 2A to 4A.

[0565] Acid-generating agent: "Ditertiary butyl diphenyl iodonium nonafluorobutanesulfonate" manufactured by Midori Chemical Co., Ltd. (listed as "DTDPI" in the table)

[0566] Pyridinium paratoluenesulfonic acid (listed as “PPTS” in the table)

[0567] Crosslinking agent: "Nikalac MX270" manufactured by Sanwa Chemical Co., Ltd. (listed as "Nikalac" in the table)

[0568] "TMOM-BP" manufactured by Honshu Chemical Industry Co., Ltd. (listed as "TMOM" in the table)

[0569] Organic solvent: PGMEA / PGME=7:3

[0570] PGMEA: Propylene glycol monomethyl ether acetate

[0571] PGME: 1-Methoxy-2-Propanol (Propylene Glycol Monomethyl Ether)

[0572] [Table 1A]

[0573]

[0574] [Table 2A]

[0575]

[0576] [Table 3A]

[0577]

[0578] [Table 4A]

[0579]

[0580] From the above results, it can be seen that the lithography underlayer forming composition of the example has excellent EB sensitivity and EUV sensitivity, and high exposure sensitivity. Furthermore, it can be seen that the lithography underlayer forming composition of the example has excellent film formation properties.

[0581] In addition, it can be seen that the polymer contained in the lithography underlayer forming composition of the example has high solubility in solvents.

[0582] In light of the above, the lithography underlayer forming composition of the present invention can increase the exposure sensitivity of the lithography process and is excellent as a material for forming a lithography underlayer. Furthermore, the polymer contained in the lithography underlayer forming composition of the present invention is also excellent as a material for forming a lithography underlayer in that it has high solubility and excellent film-forming properties.

[0583] [2] Example of a positive type resist composition (second invention)

[0584] [analyze]

[0585] Fourier transform infrared spectroscopy (FT-IR) spectra were measured using a JASCO FT / IR4200 (manufactured by Japan Spectroscopic Corporation).

[0586] 1 H-NMR spectrum, 13 The C-NMR spectrum was measured using FTECS-400K (manufactured by Nippon Electronics Co., Ltd.) at a frequency of 400 MHz, with DMSO-d6 as the solvent and Me4Si (TMS) as the internal standard.

[0587] The number-average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the polymer were measured by size exclusion chromatography (SEC) under the following conditions. Calibration was performed using standard polystyrene (narrow molecular weight distribution).

[0588] (Measurement conditions, Device: HLC-8220 SEC device, manufactured by Tosoh Corporation, Column: TSKgel Super AW3000, AW2500×2, Detector: RI, UV, Eluent: DMF (20mM) solution of LiBr and phosphoric acid, Flow rate: 0.6mL / min)

[0589] [Evaluation 1]

[0590] Solubility

[0591] The solubility of the polymer was confirmed to be soluble in the following solvents at room temperature (25°C). The solvents tested were DMF (N,N-dimethylformamide), NMP (N-methylpyrrolidone), MEK (methyl ethyl ketone), PGME, and PGMEA. For the above solvents, solubility was evaluated as "Good (A)" when 3 mg or more of the resin was dissolved in 1 mL of solvent.

[0592] <Tabernacle Nature and Tabernacle Reduction Nature>

[0593] A methyl ethyl ketone (MEK) solution (2 mass%) of the polymer was applied onto a silicon wafer treated with hexamethyldisilazane (HMDS) by spin coating (2800 rpm for 30 seconds) to form a thin film.

[0594] The film thickness was measured using a film thickness measuring device (Ellipsometer SE-101 (manufactured by Photonic Lattice Co., Ltd.), surface profiling system Dektak-XT (manufactured by Bruker)) (measurement wavelength 636 nm).

[0595] Regarding film formation properties, the thickness of the formed thin film is described, and these are evaluated as having good film formation properties.

[0596] The film thickness was measured using a film thickness measuring device (Ellipsometer SE-101 (manufactured by Photonic Lattice Co., Ltd.), surface profiling system Dektak-XT (manufactured by Bruker)) (measurement wavelength 636 nm).

[0597] Regarding the film-forming properties, the above-mentioned thin film (film) has good film-forming properties.

[0598] Next, the film thickness was measured after immersion in a 2.38 mass% aqueous solution of TMAH (Tetramethyl ammonium hydroxide).

[0599] The difference between the film thickness before immersion in the TMAH aqueous solution and the film thickness after immersion in the TMAH aqueous solution was calculated, and the value (%) obtained by dividing this by the film thickness before immersion in the TMAH aqueous solution was evaluated as the thickness loss property. The smaller the reduction in film thickness after immersion in the TMAH aqueous solution compared to the film thickness before immersion in the TMAH aqueous solution, the more the film loss is suppressed, which is desirable; and the less reduction, the more the film loss is suppressed, which is more desirable. This evaluates the usefulness as a positive-type resist material, particularly when using an alkaline developer.

[0600] [Synthesis of Iodine-Containing Monomers]

[0601] Synthesis Example 1B (Synthesis of 2,4,6-triiodophenyl acrylate (TIPA))

[0602] [Chemical Formula 21]

[0603]

[0604] 2,4,6-triiodophenol (TIP) (15 mmol, 7.08 g) and triethylamine (20 mL) were dissolved in tetrahydrofuran (20 mL) at 0°C to form a solution. Next, acryloyl chloride (AC) (20 mmol, 1.81 g, 1.62 mL) was slowly added to this solution. Next, the resulting mixture was slowly brought to room temperature (25°C) and stirred for 24 hours.

[0605] Subsequently, the solution was filtered, and the filtrate was concentrated using a rotary evaporator. Chloroform was added to the residue, and the resulting suspension was washed with 0.1N hydrochloric acid and a saturated sodium bicarbonate solution, and separated to obtain the organic phase. The organic phase was dried with anhydrous magnesium sulfate and concentrated using a rotary evaporator. The residue was purified by silica gel column chromatography (eluent: chloroform / hexane (1 / 1)) to obtain a white powder. The white powder was dissolved in a chloroform / hexane mixture and recrystallized to obtain 2,4,6-triiodophenylacrylate (TIPA) as a colorless solid (yield 46.0%). The analysis results are shown below.

[0606] FT-IR(KBr, cm -1 ): 3030(νC-H aromatic), 1730(νC=O ester), 1635, 1530 and 702(νC=C aromatic), 1137(νC-OC ether), 535(νI-C halobenzene).

[0607] 1 H-NMR (400MHz, DMSO-d6, TMS): δ(ppm)=6.26(d, J=10.4Hz, 1H, CH2=), 6.45(dd, 1H, J=6.8Hz, =CH-), 6.62(d, J=17.6Hz, 1H, CH2=), 8.18(s, 1H, aromatic H).

[0608] 13 C-NMR (100MHz, DMSO-d6, TMS): δ(ppm)=162.08(C=0), 151.77(C=C of aromatic), 147.16(C=C of aromatic), 134.56(CH2=CH), 127.12(CH2=CH), 91.71(C=C of aromatic), 91.66(C=C of aromatic).

[0609] Elemental analysis (C9H5I3O2): (Calculated value) C20.56, H0.96, I72.40. (Measured value) C20.47, H1.05, I72.68.

[0610] [Manufacturing of Polymers]

[0611] Preparation Example 1B (Preparation of Poly(HS-co-TIPA-co-ADA))

[0612] [Chemical Formula 22]

[0613]

[0614] 2,4,6-triiodophenylacrylate (TIPA), 4-vinylphenylacetate (VPA), and 2-methyladamantan-2-ylacrylate (ADA) were added in an input ratio of VPA:TIPA:ADA = 9:4:7, and polymerized in N,N-dimethylformamide (DMF) at 60°C for 20 hours using azobisisobutyronitrile (AIBN) as an initiator to obtain the corresponding copolymer (Poly(VPA-co-TIPA-co-ADA)) with a yield of 88%. Next, the copolymer was hydrolyzed with an aqueous sodium hydroxide solution to obtain the corresponding polymer (Poly(HS-co-TIPA-co-ADA)). The analysis results are shown below. In addition, the results of the solubility evaluation, film formation evaluation, and film reduction evaluation are shown in Table 1B.

[0615] 97% yield

[0616] Mn=25,770, Mw / Mn=3.51.

[0617] [Table 1B]

[0618]

[0619] From the results of Table 1B, it can be seen that the polymer obtained in Preparation Example 1B has high solubility in solvents and excellent film-forming properties. In addition, it can be seen that the film reduction properties with respect to the developer are also good. Therefore, it can be seen that the polymer containing repeating units derived from the iodine-containing monomer represented by Formula (1B) of the present invention is excellent as a material for forming lithography films, and particularly excellent as a material for forming resist films.

[0620] [Preparation and Evaluation of Positive-Type Resist Compositions]

[0621] Comparative Synthesis Example 1B (Synthesis of Modified Dimethylnaphthalene Formaldehyde Resin CR-1)

[0622] A 4-neck flask with a volume of 10 L capable of bottom detachment was prepared, equipped with a dimrose condenser, a thermometer, and a stirring blade. In this 4-neck flask, 1.09 kg (7 mol, manufactured by Mitsubishi Gas & Chemical Co., Ltd.), 2.1 kg of a 40 mass% aqueous formalin solution (28 mol as formaldehyde, manufactured by Mitsubishi Gas & Chemical Co., Ltd.), and 0.97 mL of 98 mass% sulfuric acid (manufactured by Kanto Chemical Co., Ltd.) were added under a nitrogen stream, and the mixture was reacted for 7 hours at 100°C under atmospheric pressure while refluxing. Afterward, 1.8 kg of ethylbenzene (manufactured by Fujifilm Wako Pure Chemical Co., Ltd., Reagent Grade Special) was added to the reaction mixture as a diluent solvent, and after standing, the aqueous phase at the bottom was removed. Furthermore, neutralization and washing were performed, and ethylbenzene and unreacted 1,5-dimethylnaphthalene were removed under reduced pressure, thereby obtaining 1.25 kg of a light brown solid dimethylnaphthalene formaldehyde resin. The molecular weight Mn of the obtained dimethylnaphthalene formaldehyde resin was 562.

[0623] Next, a 4-neck flask with a volume of 0.5 L equipped with a dimrose condenser, a thermometer, and a stirring blade was prepared. In this 4-neck flask, under a nitrogen stream, 100 g (0.51 mol) of the dimethylnaphthalene-formaldehyde resin and 0.05 g of p-toluenesulfonic acid were added, heated to 190°C for 2 hours, and then stirred. Subsequently, 52.0 g (0.36 mol) of 1-naphthol was added, and the mixture was further heated to 220°C for 2 hours. After solvent dilution, neutralization and washing were performed, and the solvent was removed under reduced pressure to obtain 126.1 g of a blackish-brown solid modified resin (CR-1). The obtained resin (CR-1) had Mn: 885, Mw: 2220, and Mw / Mn: 4.17. The Mn, Mw, and Mw / Mn of the resin (CR-1) were determined as polystyrene equivalents under the following measurement conditions by gel permeation chromatography (GPC) analysis.

[0624] Device: Shodex GPC-101 type (Product of Showa Denko Co., Ltd.)

[0625] Column: KF-80M×3

[0626] Eluent: THF 1 mL / min

[0627] Temperature: 40℃

[0628] Examples A1B~A2B and Comparative Example A1B (Preparation of positive-type resist composition and resist film)

[0629] Positive-type resist compositions with the compositions shown in Table 2B were each prepared using the polymer obtained in Preparation Example 1B and the resin obtained in Comparative Synthesis Example 1B. In addition, a positive-type resist composition was also prepared using a novolak resin (PSM4357 (model number) manufactured by Gun-Ei Chemical Industry Co., Ltd.) as a standard for evaluating etching resistance.

[0630] The following were used for the acid generator, acid diffusion control agent, and organic solvent. In Table 2B, the numbers in parentheses represent the amount (parts by mass).

[0631] Acid generator

[0632] TPS-109: Triphenylsulfonium trifluoromethanesulfonate manufactured by Midori Chemical Co., Ltd., TPS-109 (trade name)

[0633] DTDPI: Dieterial butyl diphenyl iodonium nonafluorobutanesulfonate (DTDPI) manufactured by Midori Chemical Co., Ltd.

[0634] Acid Diffusion Control Agent

[0635] TOA: Tri-n-octylamine (TOA, manufactured by Kanto Chemical Co., Ltd.)

[0636] Organic Solvents

[0637] PGME: Propylene glycol monomethyl ether (PGME, manufactured by Kanto Chemical Co., Ltd.)

[0638] PGMEA: Propylene glycol monomethyl ether acetate (PGMEA, manufactured by Kanto Chemical Co., Ltd.)

[0639] [Table 2B]

[0640]

[0641] [Evaluation 2]

[0642] (1) Formation of a resist film

[0643] The positive type resist compositions listed in Table 2B (Examples A1B to A2B and Comparative Example A1B) were spin-coated onto a silicon wafer treated with hexamethyldisilazane (HMDS). Then, a pre-exposure bake (PB) was performed in an oven at 110°C to form a resist film with a thickness of 40 nm.

[0644] (2) Formation of the resist pattern

[0645] For the resist film obtained in (1) above, electron beams were irradiated using an electron beam lithography device (ELS-7500, manufactured by Elionix Co., Ltd., 50 keV) with a 1:1 line-and-space setting of 50 nm intervals. After irradiation, the resist film was heated to 110°C for 90 seconds and immersed in a developer solution for 60 seconds to perform development. After that, the resist film was washed with ultrapure water for 30 seconds and dried to form a resist pattern.

[0646] A 2023-

[0647] The shape of the obtained L / S (1:1) resist pattern with a spacing of 50 nm was observed using an electron microscope manufactured by Hitachi, Ltd. (S-4800, product name). The shape of the resist pattern after development was evaluated according to the following criteria. The results are shown in Table 3B.

[0648] A: There was no pattern collapse, and the rectangularity was better than Comparative Example A1B.

[0649] B: Rectangularity was better than Comparative Example A1B, but 1 to 3 pattern collapses were observed within a range of 1 μm × 1.5 μm.

[0650] C: Equivalent to Comparative Example A1B or inferior to Comparative Example A1B.

[0651] Meanwhile, in Comparative Example A1B, pattern collapse was observed in the resist pattern shape after development, and the rectangularity was poor.

[0652] (3) Etching resistance

[0653] The positive type resist compositions listed in Table 2B (Examples A1B to A2B and Comparative Example A1B) were spin-coated onto a silicon wafer treated with hexamethyldisilazane (HMDS). Then, a pre-exposure bake (PB) was performed in an oven at 110°C to form a resist film with a thickness of 40 nm.

[0654] An etching test was performed on the above resist film, and the etching rate was measured. The etching conditions are shown below.

[0655] (Etching conditions)

[0656] Etching device: RIE-10NR (product name) manufactured by Samco Co., Ltd.

[0657] Output: 50W

[0658] Pressure: 20Pa

[0659] Time: 2 minutes

[0660] Etching gas: Ar gas flow rate: CF4 gas flow rate: O2 gas flow rate = 50:5:5 (sccm)

[0661] Based on the etching rate of the resist film obtained from the evaluation composition using novolak resin, the etching resistance of each resist film was evaluated according to the following evaluation criteria. The results are shown in Table 3B.

[0662] (metewand)

[0663] A: The etching rate was less than -10% compared to the resist film of novolak resin.

[0664] B: Compared to the resist film of novolak resin, the etching rate was -10% or higher and less than 0%.

[0665] C: The etching rate was 0% or higher compared to the resist film of the novolak resin.

[0666] [Table 3B]

[0667]

[0668] From the results of the examples, it can be seen that a resist pattern formed using a positive resist composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by formula (1B) of the present invention has no pattern collapse and has excellent resolution. In addition, it can be seen that a resist film formed using a positive resist composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by formula (1B) of the present invention has excellent etching resistance.

[0669] From the above, it can be seen that the positive-type resist composition of the present invention is excellent as a material for forming a resist film. In addition, it can be seen that the resist pattern formed using the positive-type resist composition has excellent resolution.

Claims

Claim 1 A lithography sublayer forming composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by the following general formula (1A). [Chemical Formula 1] (during food, X 1A is a hydrogen atom, a methyl group, or a halogen atom, and Y 1A is -O- or -NH-, aa is 0 or 1, and R A is an organic group containing iodine atoms with 2 to 30 carbon atoms. Claim 2 In paragraph 1, R A a. A lithography sublayer forming composition, which is an organic group represented by the following general formula (2A). [Chemical Formula 2] (during food, L A is a directly bonded or divalent organic group having 1 to 24 carbon atoms. ba is an integer from 1 to 5.) Claim 3 In paragraph 1 or 2, R A a. A lithography sublayer forming composition comprising at least one selected from the group consisting of an organic group represented by the following general formula (3A) and an organic group represented by the following general formula (4A). [Chemical Formula 3] (during food, L A is a directly bonded, or a divalent organic group having 1 to 24 carbon atoms. Claim 4 A lithography underlayer forming composition comprising, in any one of claims 1 to 3, additionally containing a solvent. Claim 5 A lithography sublayer forming composition comprising at least one selected from the group consisting of an acid generating agent and an acid crosslinking agent, in any one of claims 1 to 4. Claim 6 A lithography sublayer formed from the lithography sublayer forming composition described in paragraph 5. Claim 7 A method for forming a resist pattern using a lithography underlayer forming composition described in paragraph 5. Claim 8 A positive-type resist composition comprising a polymer containing repeating units derived from an iodine-containing monomer represented by the following formula (1B). [Chemical Formula 4] (during food, X 1B is a hydrogen atom, a methyl group, or a halogen atom, and Y 1B is -O- or -NH-, ab is 0 or 1, and R B is a group having 2 to 30 carbon atoms containing an iodine atom. Claim 9 In paragraph 8, R B a. A positive-type resist composition represented by the following formula (2B). [Chemical Formula 5] (during food, L B is a directly bonded or divalent group having 1 to 24 carbon atoms, and R 1B Each is independently an alkyl group having 1 to 30 carbon atoms that may have substituents, an aryl group having 6 to 30 carbon atoms that may have substituents, an alkenyl group having 2 to 30 carbon atoms that may have substituents, an alkynyl group having 2 to 30 carbon atoms that may have substituents, an alkoxy group having 1 to 30 carbon atoms that may have substituents, a halogen atom other than iodine, a nitro group, an amino group, a carboxylic acid group, a crosslinking group, a dissociable group, a thiol group, or a hydroxyl group. bb is an integer from 1 to 5, cb is an integer from 0 to 4, and bb+cb is 1 to 5.) Claim 10 In Article 8 or 9, R B A positive-type resist composition comprising at least one selected from the group consisting of a group represented by the following formula (3B) and a group represented by the following formula (4B). [Chemical Formula 6] (during food, L B is a directly bonded or divalent group having 1 to 24 carbon atoms. Claim 11 A positive-type resist composition according to any one of claims 8 to 10, wherein the polymer further comprises repeating units derived from a phenolic hydroxyl group-containing monomer. Claim 12 A positive-type resist composition according to claim 11, wherein the phenolic hydroxyl group-containing monomer is at least one selected from the group consisting of 4-vinylphenol, 4-hydroxyphenyl(meth)acrylate, and 4-hydroxyphenyl(meth)acrylamide. Claim 13 A positive-type resist composition according to claim 11 or 12, wherein the phenolic hydroxyl group-containing monomer is 4-vinylphenol. Claim 14 A positive type resist composition according to any one of claims 11 to 13, wherein the molar ratio [phenolic hydroxyl group-containing monomer / iodine-containing monomer] of the repeating unit derived from the phenolic hydroxyl group-containing monomer to the repeating unit derived from the iodine-containing monomer represented by formula (1B) is 20 / 80 to 95 / 5. Claim 15 A positive-type resist composition according to any one of claims 8 to 14, wherein the polymer further comprises repeating units derived from an adamantane structure-containing monomer. Claim 16 A positive-type resist composition according to claim 15, wherein the adamantane structure-containing monomer is at least one selected from the group consisting of adamantane-1-yl(meth)acrylate, 2-methyladamantan-2-yl(meth)acrylate, 2-ethyladamantan-2-yl(meth)acrylate, and N-(1-adamanthyl)(meth)acrylamide. Claim 17 A positive-type resist composition according to claim 15 or 16, wherein the adamantane structure-containing monomer is 2-methyladamantan-2-yl(meth)acrylate. Claim 18 A positive resist composition according to any one of claims 15 to 17, wherein the molar ratio [adamantane structure-containing monomer / iodine-containing monomer] of the repeating unit derived from the adamantane structure-containing monomer to the repeating unit derived from the iodine-containing monomer represented by formula (1B) is 20 / 80 to 99 / 1. Claim 19 A positive-type resist composition comprising a solvent additionally in any one of claims 8 to 18. Claim 20 A positive-type resist composition according to any one of claims 8 to 19, further comprising at least one selected from the group consisting of an acid-generating agent and a crosslinking agent. Claim 21 A resist film formed from a positive-type resist composition described in any one of claims 8 to 20. Claim 22 A method for forming a resist pattern using a positive type resist composition described in any one of claims 8 to 20. Claim 23 A method for forming a resist pattern, comprising: a process of forming a resist film on a substrate using a positive-type resist composition described in any one of claims 8 to 20; and a process of exposing the resist film to light and developing it.

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