JP7709679B2 - Compound, (co)polymer, composition, and pattern forming method - Google Patents

Description

The present invention relates to a compound, a (co)polymer, a composition, and a pattern forming method.

In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, semiconductors (patterns) and pixels have been rapidly miniaturized due to advances in lithography technology. In general, the method of miniaturizing pixels is to shorten the wavelength of the exposure light source. Specifically, ultraviolet rays such as g-line and i-line were used in the past, but currently, far-ultraviolet exposure such as KrF excimer laser (248 nm) and ArF excimer laser (193 nm) has become the center of mass production, and extreme ultraviolet (EUV) lithography (13.5 nm) is being introduced. Electron beams (EB) are also used to form fine patterns.

Conventional resist materials are polymeric resist materials capable of forming amorphous films, such as polymethyl methacrylate, polyhydroxystyrene having an acid-dissociable group, or polyalkyl methacrylate (see, for example, Non-Patent Document 1).
Conventionally, a thin resist film is prepared by applying a solution of such a resist material onto a substrate, and then irradiating the thin resist film with ultraviolet light, far ultraviolet light, an electron beam, extreme ultraviolet light, or the like to form a line pattern of about 10 to 100 nm.

In addition, the reaction mechanism of electron beam or extreme ultraviolet lithography is different from that of normal photolithography. Furthermore, in electron beam or extreme ultraviolet lithography, the goal is to form fine patterns of several nm to several tens of nm. As the resist pattern dimensions become smaller, resist materials with higher sensitivity to the exposure light source are required. In particular, in extreme ultraviolet lithography, there is a demand for higher sensitivity in terms of throughput.
As a resist material that can solve the above-mentioned problems, inorganic resist materials containing metal elements such as titanium, tin, hafnium, and zirconium have been proposed (see, for example, Patent Document 1).

JP 2015-108781 A

Shinji Okazaki and 8 others, "Lithography Technology: 40 Years," S&T Publishing, December 9, 2016

However, previously developed resist compositions with high sensitivity characteristics have issues such as insufficient pattern quality, such as large pattern defects and roughness, insufficient sensitivity improvement, and insufficient etching resistance. Furthermore, the stability of the resist solution is also insufficient, making it difficult to deploy them in actual semiconductor manufacturing. In light of these circumstances, there is a demand for resists that combine high resolution and high sensitivity.

In particular, in lithography using extreme ultraviolet light to create fine lines in the range of several nm to several tens of nm, materials and processes are being considered for positive pattern formation using an alkaline developer (PTI) and negative pattern formation using an organic solvent developer (NTI) for patterns formed with hydrophilic and hydrophobic resins after exposure and baking. From the perspective of the solubility of the resist resin remaining as a resin pattern in the developer, the solubility of the hydrophobic resin pattern in PTI in an alkaline developer is greater than that of the hydrophilic resin pattern in NTI in an organic solvent developer, making it more difficult to create fine lines with NTI, and pattern collapse caused by resin swelling makes it difficult to ensure sufficient resolution on the fine line side.

In view of the above circumstances, the present invention aims to provide a resin material capable of forming a film having high resolution and high sensitivity, a resist composition containing the same, and a method for forming a resist pattern and a method for forming an insulating film using the same.

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result have found that (co)polymers containing a compound having a specific structure have high solubility in safe solvents, and that when these compounds or the like are used in compositions for forming films for photography or resists, films having high resolution and high sensitivity can be formed, thereby completing the present invention.
That is, the present invention is as follows.

[1]
A compound having one or more halogens and two or more substituents having an unsaturated double bond.
[2]
The compound according to [1], represented by the following general formula (A):

(In formula (A),
R ¹ , R ² , and R ³ each independently represent a hydrogen atom, a halogen, a linear organic group having 1 to 20 carbon atoms, a branched organic group having 3 to 20 carbon atoms, or a cyclic organic group having 3 to 20 carbon atoms;
L represents a divalent linking group;
A represents an organic group having 1 to 30 carbon atoms;
X represents Cl, Br, or I, or a hydrocarbon group having 1 to 30 carbon atoms which contains a halogen atom selected from the group consisting of Cl, Br, and I and is bonded to A via a single bond, an ester group, an ether group, an amide group, an imide group, a urethane group, a urea group, a thioether group, a phosphine group, or a phosphate ester group;
n ⁰ represents an integer from 2 to 5;
ⁿ² represents an integer of 1 to 5.
[3]
The compound according to [2], wherein general formula (A) is represented by general formula (1).

(In formula (1),
R ¹ represents a hydrogen atom, a halogen atom or a methyl group;
R ⁴ each independently represents a hydrogen atom, a linear organic group having 1 to 20 carbon atoms, a branched organic group having 3 to 20 carbon atoms, or a cyclic organic group having 3 to 20 carbon atoms;
A represents an organic group having 1 to 30 carbon atoms;
n ⁰ represents an integer from 2 to 5;
ⁿ¹ represents 0 or 1;
ⁿ² represents an integer of 1 to 5.
[4]
The compound according to [2] or [3], wherein A contains an aromatic ring.
[5]
The compound according to any one of [1] to [4], wherein the contents of Fe, Al, Sb, Ru and W are less than 1 ppm.
[6]
A (co)polymer having a structural unit derived from the compound according to any one of [1] to [5].
[7]
The copolymer according to [6], further comprising a structural unit having a functional group whose solubility in an alkaline developer is improved by the action of an acid or a base.
[8]
The (co)polymer according to [6] or [7], wherein the contents of Fe, Al, Sb, Ru and W are less than 1 ppm.
[9]
A resist composition comprising the compound according to any one of [1] to [5] and/or the (co)polymer according to any one of [6] to [8].
[10]
The resist composition according to [9], further comprising an acid generator, a photobase generator, or a base compound.
[11]
forming a film of the resist composition according to [9] or [10] on a wafer;
forming an optical image as a pattern on a resist film on a wafer by exposure; and forming a resist pattern based on the optical image by development.
A pattern forming method comprising the steps of:
[12]
A method for forming an insulating film, comprising the method according to [11].
[13]
General formula (a):
(In formula (a),
R ⁴ each independently represents a hydrogen atom, a linear organic group having 1 to 20 carbon atoms, a branched organic group having 3 to 20 carbon atoms, or a cyclic organic group having 3 to 20 carbon atoms;
A represents an organic group having 1 to 30 carbon atoms;
n ⁰ represents an integer of 2 to 5;
ⁿ¹ represents 0 or 1;
n ² represents an integer of 1 to 5.
A compound represented by the formula:
General formula (b):
In formula (b), R ¹ represents a hydrogen atom, a halogen atom, or a methyl group;
R _B is selected from the group consisting of a hydroxyl group, a halogen atom, and a (meth)acryloyloxy group.
With a compound represented by
General formula (1):
(In formula (1), R ¹ , R ⁴ , A, n ⁰ , n ¹ , and n ² are as defined above.)
A method for producing a compound represented by the formula:
[14]
A step of purifying the compound represented by general formula (1) obtained by the production method according to [13] to remove metal impurities;
The method according to [13], comprising:
[15]
The method according to claim 14, wherein the purification comprises dissolving the compound in an organic solvent to obtain a solution, and extracting metal impurities contained in the solution with an acidic aqueous solution.
[16]
The method according to claim 14, wherein the purification comprises dissolving the compound in a solvent to obtain a solution, and passing the solution through a filter.
[17]
A step of polymerizing the compound represented by general formula (1) obtained by the production method according to any one of [13] to [16] to obtain a (co)polymer; and A step of purifying the (co)polymer to remove metal impurities.
A method for producing a (co)polymer, comprising:
[18]
The method according to [17], wherein the purification comprises dissolving the (co)polymer in an organic solvent to obtain a solution, and extracting metal impurities contained in the solution with an acidic aqueous solution.
[19]
The method according to [17], wherein the purification comprises dissolving the (co)polymer in a solvent to obtain a solution, and passing the solution through a filter.

The present invention provides compounds and compositions capable of forming films with high resolution and sensitivity, as well as methods for forming resist patterns and insulating films using the same.

Hereinafter, an embodiment of the present invention will be described (hereinafter, may be referred to as the "present embodiment"). Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to only the present embodiment.

In the present specification, (meth)acrylate means acrylate and methacrylate. Other terms having the expression (meth) are also interpreted in the same manner as (meth)acrylate.
In this specification, (co)polymer means a homopolymer and a copolymer.

[Halogen-containing polymerizable compound]
One of the present embodiments relates to a compound having one or more halogens and two or more substituents having an unsaturated double bond, and more specifically, to a halogen-containing polymerizable compound represented by general formula (A).
(In formula (A),
R ¹ , R ² , and R ³ each independently represent a hydrogen atom, a halogen, a linear organic group having 1 to 20 carbon atoms, a branched organic group having 3 to 20 carbon atoms, or a cyclic organic group having 3 to 20 carbon atoms;
L represents a divalent linking group;
A represents an organic group having 1 to 30 carbon atoms;
X represents Cl, Br, or I, or a hydrocarbon group having 1 to 30 carbon atoms which contains a halogen atom selected from the group consisting of Cl, Br, and I and is bonded to A via a single bond, an ester group, an ether group, an amide group, an imide group, a urethane group, a urea group, a thioether group, a phosphine group, or a phosphate ester group;
n ⁰ represents an integer from 2 to 5;
ⁿ² represents an integer of 1 to 5.

The compound of the present embodiment preferably contains two or more ester moieties containing a polymerizable functional group in the compound. For example, by using a copolymer containing at least a structural unit derived from the compound of the present embodiment and a structural unit having a functional group in which a hydrophilic-hydrophobic conversion reaction proceeds with an acid to improve the solubility in an alkaline developer or reduce the solubility in an organic solvent developer as a resin for lithography, the solubility of the resin pattern formed after the processes of exposure, baking (PEB, Post Exposure Bake), and development can be suppressed in the developer, and the pattern collapse due to mechanisms such as resin swelling, particularly in the formation of fine patterns, can be suppressed, and the resolution of the fine line pattern can be improved. In addition, particularly for monomers having a phenol structure, the introduction of the ester structure into the phenolic hydroxyl group can reduce the change over time of the resist resin derived from the pKa of the phenolic hydroxyl group, and as a result, the effect of maintaining the pattern quality after aging can also be secondary.
The compound in this embodiment is characterized in that it contains a halogen element. By containing a halogen element, activity in the lithography process is improved, and the efficiency in lithography is improved or a margin for efficiency in lithography is secured, which allows a more suitable distribution of performance in material design, which ultimately contributes to improved lithography performance and improved manufacturing stability. This effect is particularly noticeable in the exposure process of short wavelengths such as EUV and EB or electron beams.

The compound represented by formula (A) is preferably a compound represented by formula (1).
(In formula (1),
R ¹ represents a hydrogen atom, a halogen atom or a methyl group;
R ⁴ each independently represents a hydrogen atom, a linear organic group having 1 to 20 carbon atoms, a branched organic group having 3 to 20 carbon atoms, or a cyclic organic group having 3 to 20 carbon atoms;
A represents an organic group having 1 to 30 carbon atoms;
n ⁰ represents an integer from 2 to 5;
ⁿ¹ represents 0 or 1;
ⁿ² represents an integer of 1 to 5.

^R4 may be a combination of two or more selected from the group consisting of linear organic groups having 1 to 20 carbon atoms, branched organic groups having 3 to 20 carbon atoms, and cyclic organic groups having 3 to 20 carbon atoms.

R ⁴ may have a substituent. Examples of R ⁴ include an alkyl group having 1 to 20 carbon atoms, 1 to 10 carbon atoms, or 1 to 6 carbon atoms, which may have a substituent; an alkenyl group having 2 to 20 carbon atoms, 2 to 10 carbon atoms, or 2 to 6 carbon atoms, which may have a substituent; an alkynyl group having 2 to 20 carbon atoms, 2 to 10 carbon atoms, or 2 to 6 carbon atoms, which may have a substituent; a cycloalkyl group having 3 to 20 carbon atoms, 3 to 10 carbon atoms, or 3 to 6 carbon atoms, which may have a substituent; a cycloalkenyl group having 3 to 20 carbon atoms, 3 to 10 carbon atoms, or 3 to 6 carbon atoms, which may have a substituent; a cycloalkynyl group having 3 to 20 carbon atoms, 3 to 10 carbon atoms, or 3 to 6 carbon atoms, which may have a substituent; an aryl group having 5 to 20 carbon atoms, 5 to 10 carbon atoms, or 5 to 6 carbon atoms, which may have a substituent; and combinations thereof.

Specific examples of ^R4 include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, icosyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloicosyl, adamantyl, ethylene, propylene, butylene, phenyl, naphthyl, anthracene, phenanthrene, tetracene, chrysene, triphenylene, pyrene, benzopyrene, azulene, and fluorene groups, which may have a substituent. These may contain an ether bond, a ketone bond, or an ester bond.

Here, the exemplified groups include isomers. For example, the propyl group includes n-propyl and isopropyl groups, and the butyl group includes n-butyl, sec-butyl, isobutyl, and tert-butyl groups.

The substituent for ^R4 is not particularly limited, but examples thereof include a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amino group, a thiol group, a heterocyclic group, a linear aliphatic hydrocarbon group, a branched aliphatic hydrocarbon group, a cyclic aliphatic hydrocarbon group, an aryl group, an aralkyl group, an alkoxy group, an alkenyl group, an acyl group, an alkoxycarbonyl group, an alkyloyloxy group, an aryloyloxy group, an alkylsilyl group, and various crosslinkable groups and acid-dissociable groups.

The term "crosslinkable group" refers to a group that crosslinks with the aid of an acid, an alkali, light, or heat, and crosslinks in the presence or absence of a catalyst. Examples of the crosslinkable group include, but are not limited to, a group having an allyl group, a group having a (meth)acryloyl group, a group having an epoxy (meth)acryloyl group, a group having a urethane (meth)acryloyl group, a group having a hydroxyl group, a group having a glycidyl group, a group having a vinyl-containing phenylmethyl group, a group having a styrene group, a group having an alkynyl group, a group having a carbon-carbon double bond, a group having a carbon-carbon triple bond, and groups containing these groups.

An "acid dissociable group" is a group that cleaves in the presence of an acid to generate an alkali-soluble group (e.g., a phenolic hydroxyl group, a carboxyl group, a sulfonic acid group, a hexafluoroisopropanol group), etc. The acid dissociable group is not particularly limited, but can be appropriately selected from those proposed in, for example, hydroxystyrene resins and (meth)acrylic acid resins used in chemically amplified resist compositions for KrF and ArF. Specific examples of acid dissociable groups include those described in WO 2016/158168.

A may have a substituent. Examples of compounds that form the skeleton of A include alkanes having 1 to 30 carbon atoms, 1 to 20 carbon atoms, 1 to 10 carbon atoms, or 1 to 6 carbon atoms, which may have a substituent; alkenes having 2 to 30 carbon atoms, 2 to 20 carbon atoms, 2 to 10 carbon atoms, or 2 to 6 carbon atoms, which may have a substituent; alkynes having 2 to 30 carbon atoms, 2 to 20 carbon atoms, 2 to 10 carbon atoms, or 2 to 6 carbon atoms, which may have a substituent; alkynes having 3 to 30 carbon atoms, 3 to 20 carbon atoms, which may have a substituent. , cycloalkanes having 3 to 10 carbon atoms or 3 to 6 carbon atoms; cycloalkenes having 3 to 30 carbon atoms, 3 to 20 carbon atoms, 3 to 10 carbon atoms or 3 to 6 carbon atoms which may have a substituent; cycloalkynes having 3 to 30 carbon atoms, 3 to 20 carbon atoms, 3 to 10 carbon atoms or 3 to 6 carbon atoms which may have a substituent; arenes having 5 to 30 carbon atoms, 5 to 20 carbon atoms, 5 to 10 carbon atoms or 5 to 6 carbon atoms which may have a substituent; and combinations thereof.

Specific examples of the compound that serves as the skeleton of A include, for example, methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, icosane, triacontane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloicosane, cyclotriacontane, adamantane, ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, icosene, triacontene, benzene, phenol, naphthalene, anthracene, phenanthrene, tetracene, chrysene, triphenylene, pyrene, pentacene, benzopyrene, coronene, azulene, fluorene, and combinations thereof, which may have a substituent. These may contain an ether bond, a ketone bond, or an ester bond. Preferred skeletons of A include benzene, phenol, naphthalene, anthracene, phenanthrene, tetracene, chrysene, triphenylene, pyrene, pentacene, benzopyrene, coronene, azulene, fluorene, and combinations thereof, each of which may have a substituent. More preferred skeletons of A include benzene and adamantane.

The substituents of the compound that forms the skeleton of A are not particularly limited, but examples include halogen atoms (fluorine, chlorine, bromine), hydroxyl groups, cyano groups, nitro groups, amino groups, thiol groups, heterocyclic groups, linear aliphatic hydrocarbon groups, branched aliphatic hydrocarbon groups, cyclic aliphatic hydrocarbon groups, aryl groups, aralkyl groups, alkoxy groups, alkenyl groups, acyl groups, alkoxycarbonyl groups, alkyloyloxy groups, aryloyloxy groups, alkylsilyl groups, various crosslinkable groups, and acid-dissociable groups.

The "crosslinkable group" and "acid-dissociable group" are not particularly limited, but for example, those described above in relation to ^R4 can be used.

It is preferred that at least one ⁿ¹ is 0 and at least one ⁿ¹ is 1.

ⁿ² is an integer of 1 to 5, preferably an integer of 2 to 5, and more preferably an integer of 2 to 3.

From the viewpoint of easy reactivity, the compound represented by the formula (1) is preferably a compound represented by the following formula (2).

In formula (2), R ¹ , A, n ⁰ , n ¹ and n ² are as defined in formula (1) above.

From the viewpoint of etching resistance, the compound represented by the formula (1) is more preferably a compound represented by the following formula (3).

In formula (3), B represents an organic group having 5 to 30 carbon atoms and containing an aromatic ring, and R ¹ , n ⁰ , n ¹ and n ² are as defined in formula (1) above.

B may have a substituent. Examples of compounds that form the skeleton of B include arenes having 5 to 30 carbon atoms, 5 to 20 carbon atoms, 5 to 10 carbon atoms, or 5 to 6 carbon atoms, which may have a substituent.

Specific examples of compounds that may be the skeleton of B include, for example, benzene, phenol, naphthalene, anthracene, phenanthrene, tetracene, chrysene, triphenylene, pyrene, pentacene, benzopyrene, coronene, azulene, fluorene, and combinations thereof, which may have a substituent. These may contain ether bonds, ketone bonds, and ester bonds. A more preferred skeleton of B is benzene.

The substituents of the compound that forms the skeleton of B are not particularly limited, but examples include halogen atoms (fluorine, chlorine, bromine), hydroxyl groups, cyano groups, nitro groups, amino groups, thiol groups, heterocyclic groups, linear aliphatic hydrocarbon groups, branched aliphatic hydrocarbon groups, cyclic aliphatic hydrocarbon groups, aryl groups, aralkyl groups, alkoxy groups, alkenyl groups, acyl groups, alkoxycarbonyl groups, alkyloyloxy groups, aryloyloxy groups, alkylsilyl groups, various crosslinkable groups, and acid-dissociable groups, and preferably hydroxyl groups or acid-dissociable groups.

The "crosslinkable group" and "acid-dissociable group" are not particularly limited, but for example, those described above in the description of R ⁴ can be used. Although not particularly limited, the acid-dissociable group bonded to the aromatic ring of B is preferably a group that is cleaved in the presence of an acid to generate a hydroxyl group.

From the viewpoint of etching resistance, the compound represented by the formula (1) is more preferably a compound represented by the following formula (3').

In formula (3'), B' represents an organic group having 5 to 30 carbon atoms including an alicyclic ring, and R ¹ , n ⁰ , n ¹ and n ² are as defined in formula (1) above.

B' may have a substituent. Examples of the compound that serves as the skeleton of B' include cycloalkanes having 5 to 30 carbon atoms, 5 to 20 carbon atoms, 5 to 10 carbon atoms, or 5 to 6 carbon atoms, which may have a substituent; cycloalkenes having 5 to 30 carbon atoms, 5 to 20 carbon atoms, 5 to 10 carbon atoms, or 5 to 6 carbon atoms, which may have a substituent; cycloalkynes having 5 to 30 carbon atoms, 5 to 20 carbon atoms, 5 to 10 carbon atoms, or 5 to 6 carbon atoms, which may have a substituent; and combinations thereof.

Specific examples of compounds that may be the skeleton of B' include, for example, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloicosane, cyclotriacontane, adamantane, and combinations thereof, which may have a substituent. These may contain ether bonds, ketone bonds, and ester bonds. A more preferred skeleton of B' is adamantane.

The substituents of the compound that forms the skeleton of B' are not particularly limited, but examples include halogen atoms (fluorine, chlorine, bromine), hydroxyl groups, cyano groups, nitro groups, amino groups, thiol groups, heterocyclic groups, linear aliphatic hydrocarbon groups, branched aliphatic hydrocarbon groups, cyclic aliphatic hydrocarbon groups, aryl groups, aralkyl groups, alkoxy groups, alkenyl groups, acyl groups, alkoxycarbonyl groups, alkyloyloxy groups, aryloyloxy groups, alkylsilyl groups, various crosslinkable groups, and acid-dissociable groups.

The "crosslinkable group" and "acid-dissociable group" are not particularly limited, but for example, those described above in relation to ^R4 can be used.

Specific examples of the halogen-containing polymerizable compound of the present embodiment are shown below, but are not limited thereto. In the following examples, R ¹ represents a hydrogen atom or a methyl group.

[Method of producing halogen-containing polymerizable compound]
As a method for synthesizing the halogen-containing polymerizable compound of the present embodiment, for example, a method for introducing a halogen group (e.g., an iodine group) into an alcohol derivative containing a hydroxyl group-containing aromatic group and then subjecting the alcohol group to an esterification reaction can be mentioned.
As a specific example of a method for introducing an iodine group, there is known a method in which a hydroxybenzyl alcohol derivative is subjected to an iodination reaction to react with iodine chloride in an organic solvent (e.g., Japanese Patent No. 5754842), a method in which iodine is dropped into an alkaline aqueous solution of phenol in an alkaline atmosphere in the presence of β-cyclodextrin (JP-A-63-101342, JP-A-2003-64012), and the like.
When multiple iodines are to be introduced, it is preferable to use an iodination reaction via iodine chloride in an organic solvent.
The alcohol moiety of the iodine-introduced hydroxybenzyl alcohol derivative thus prepared is esterified by the method described below, whereby the halogen-containing polymerizable compound of this embodiment can be synthesized.

A method for producing the halogen-containing polymerizable compound of this embodiment includes, for example, a method of reacting an iodine-containing hydroxy compound represented by general formula (a) with a (meth)acrylic acid compound represented by general formula (b), but is not limited thereto.

(In formula (a), R ⁴ , A, n ⁰ , n ¹ and n ² are as defined in formula (1)).
(In formula (b), R ¹ is as defined in formula (1). R _B is selected from the group consisting of a hydroxyl group, a halogen atom, and a (meth)acryloyloxy group. R _B is preferably a halogen atom such as a chlorine atom.)

The compound represented by the general formula (a) is preferably a compound represented by the general formula (a1).
(In formula (a1), A, n ⁰ , n ¹ and n ² are as defined in formula (1) above.)

The compound represented by the general formula (a) is preferably a compound represented by the general formula (a2).
(In formula (a2),
B represents an organic group having 5 to 30 carbon atoms and containing an aromatic ring;
ⁿ⁰ , ⁿ¹ , and ⁿ² are as defined in formula (1) above.

The compound represented by the general formula (a) is preferably a compound represented by the general formula (a3).
(In formula (a3),
B' represents an organic group having 5 to 30 carbon atoms including an alicyclic ring,
ⁿ⁰ , ⁿ¹ , and ⁿ² are as defined in formula (1) above.

Examples of the (meth)acrylic acid compound represented by the general formula (b) of the present invention are shown below.
Of these (meth)acrylic acid compounds, (meth)acrylic acid chloride is preferred from the viewpoint of reactivity.

The amounts of the iodine-containing hydroxy compound represented by the general formula (a) and the (meth)acrylic acid compound represented by the general formula (b) used may be appropriately adjusted depending on the number of ⁿ⁰ .

As the solvent for this reaction, a commonly available solvent can be used. For example, alcohols, ethers, hydrocarbons, halogenated solvents, etc. can be used as appropriate as long as they do not inhibit the reaction. A mixture of multiple solvents can also be used as long as they do not inhibit the reaction. Since water inhibits the reaction, it is preferable to use a dehydrated solvent.

The reaction temperature and reaction time depend on the substrate concentration and the catalyst used, but generally the reaction temperature is -20°C to 100°C, the reaction time is 1 to 10 hours, and the pressure is normal, reduced, or increased. The reaction can be carried out by appropriately selecting a known method such as batch, semi-batch, or continuous.

A polymerization inhibitor may be added to the series of reactions, and a commercially available product may be used. For example, nitroso compounds such as 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl, N-nitrosophenylhydroxylamine ammonium salt, N-nitrosophenylhydroxylamine aluminum salt, N-nitroso-N-(1-naphthyl)hydroxylamine ammonium salt, N-nitrosodiphenylamine, N-nitroso-N-methylaniline, nitrosonaphthol, p-nitrosophenol, and N,N'-dimethyl-p-nitrosoaniline; sulfur-containing compounds such as phenothiazine, methylene blue, and 2-mercaptobenzimidazole; N,N'-diphenyl-p-phenylenediamine; and N-phenyl Examples of the compound include amines such as -N'-isopropyl-p-phenylenediamine, 4-hydroxydiphenylamine, and aminophenol, quinones such as hydroxyquinoline, hydroquinone, methylhydroquinone, p-benzoquinone, and hydroquinone monomethyl ether, phenols such as p-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, catechol, 3-s-butylcatechol, and 2,2-methylenebis-(6-t-butyl-4-methylphenol), imides such as N-hydroxyphthalimide, oximes such as cyclohexaneoxime and p-quinonedioxime, and dialkylthiodipropionate. The amount of the compound to be added is, for example, 0.001 to 10 parts by mass, and preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the (meth)acrylic acid compound represented by the general formula (b).

The halogen-containing polymerizable compound of this embodiment obtained by the reaction can be isolated and purified as the desired high-purity monomer by known purification methods such as filtration, concentration, distillation, extraction, crystallization, recrystallization, column chromatography, separation and purification methods using activated carbon, etc., or a combination of these methods.

[(Co)polymer]
The (co)polymer of the present embodiment preferably has a structural unit derived from the above-mentioned halogen-containing polymerizable compound, and has a repeating unit represented by the following formula (A).

(In formula (A-1), R ¹ , R ² , R ³ , L, A, X, n ⁰ and n ² are as defined in formula (A) above.)

The compound represented by formula (A-1) is preferably a compound represented by formula (1-1).

(In formula (1-1), R ¹ , R ⁴ , A, n ⁰ , n ¹ and n ² are as defined in formula (1) above.)

The (co)polymer according to this embodiment having a structural unit derived from a halogen-containing polymerizable compound can be obtained by polymerizing the halogen-containing polymerizable compound according to this embodiment, or by polymerizing the halogen-containing polymerizable compound according to this embodiment together with another monomer. Examples of the other monomer include those having a functional group that improves solubility in an alkaline developer by the action of an acid or a base. The (co)polymer according to this embodiment can be used as a film-forming material for lithography.

The structural unit other than the structural unit derived from the halogen-containing polymerizable compound according to this embodiment is not particularly limited, and for example, those described in International Publication WO2016/125782, International Publication WO2015/115613, JP2015/117305, International Publication WO2014/175275, and JP2012/162498, or compounds represented by the following formulas (C1) and (C2) can be used.
(In formula (C1),
^R represents hydrogen or a methyl group;
R represents hydrogen or an alkyl group having 1 to 4 carbon atoms ^;
R ^C13 , together with the carbon atom to which R ^C13 is bonded, represents a cycloalkyl group or heterocycloalkyl group having 4 to 20 carbon atoms;
The dot * indicates the bonding point with the adjacent repeating unit.)
Preferably, R ^C12 represents hydrogen or an alkyl group having 1 to 3 carbon atoms, and R ^C13 , together with the carbon atom to which R ^C13 is bonded, represents a cycloalkyl group or heterocycloalkyl group having 4 to 10 carbon atoms. ^{R 13} may have a substituent (for example, an oxo group).
(In formula (C2),
^R represents hydrogen or a methyl group;
R ^C22 and R ^C23 each independently represent an alkyl group having 1 to 4 carbon atoms.
R represents an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 5 to 20 carbon atoms ^;
Two or three of R ^{to R} may form an alicyclic structure having 3 to 20 carbon atoms together with the carbon atom to which they are bonded,
The dot * indicates the bonding point with the adjacent repeating unit.)
Preferably, R ^C22 represents an alkyl group having 1 to 3 carbon atoms, and R ^C24 is a cycloalkyl group having 5 to 10 carbon atoms. The alicyclic structure formed by R ^C22 to R ^C24 may contain multiple rings, such as an adamantyl group. The alicyclic structure may have a substituent (for example, a hydroxyl group, an alkyl group).

The monomer raw material of the repeating unit represented by the general formula (C2) is not limited, but for example, 2-methyl-2-(meth)acryloyloxyadamantane, 2-ethyl-2-(meth)acryloyloxyadamantane, 2-isopropyl-2-(meth)acryloyloxyadamantane, 2-n-propyl-2-(meth)acryloyloxyadamantane, 2-n-butyl-2-(meth)acryloyloxyadamantane, 1-methyl-1-(meth)acryloyloxycyclopentane, 1-ethyl-1-(meth)acryloyloxycyclopentane, 1-methyl Examples of the monomer include 1-(meth)acryloyloxycyclohexane, 1-ethyl-1-(meth)acryloyloxycyclohexane, 1-methyl-1-(meth)acryloyloxycycloheptane, 1-ethyl-1-(meth)acryloyloxycycloheptane, 1-methyl-1-(meth)acryloyloxycyclooctane, 1-ethyl-1-(meth)acryloyloxycyclooctane, 2-ethyl-2-(meth)acryloyloxydecahydro-1,4:5,8-dimethanonaphthalene, and 2-ethyl-2-(meth)acryloyloxynorbornane. Commercially available products can be used as these monomers.

A (co)polymer having structural units derived from the halogen-containing polymerizable compound of this embodiment is preferred for improving the performance of a film-forming material for lithography.

Next, a method for producing the (co)polymer according to this embodiment by polymerization reaction will be described. The polymerization reaction is carried out by dissolving the monomers that will become the repeating units in a solvent, adding a catalyst, and heating or cooling the mixture. The reaction conditions can be set as desired depending on the type of initiator, the initiation method such as heat or light, temperature, pressure, concentration, solvent, additives, etc. The (co)polymer according to this embodiment can be produced by known methods such as radical polymerization using a radical generator such as azoisobutyronitrile or peroxide, or ionic polymerization using a catalyst such as an alkyl lithium or a Grignard reagent.

As the solvent used in the polymerization reaction, a commercially available product that is generally available can be used. For example, a wide variety of solvents such as alcohols, ethers, hydrocarbons, and halogenated solvents can be used as appropriate as long as they do not inhibit the reaction. A mixture of multiple solvents can also be used as long as they do not inhibit the above reaction.

The (co)polymer obtained by the polymerization reaction can be purified by known methods. Specifically, this can be achieved by a combination of ultrafiltration, crystallization, microfiltration, acid washing, washing with water having an electrical conductivity of 10 mS/m or less, and extraction.

[Purification method]
The compound in this embodiment is preferably obtained as a crude product by the above-mentioned reaction, and then purified to remove remaining metal impurities. That is, from the viewpoint of preventing deterioration of the resin over time and storage stability, and further from the viewpoint of process suitability and manufacturing yield due to defects when resinified and applied to a semiconductor manufacturing process, it is preferable to avoid the remaining metal impurities resulting from the contamination of metal components used as reaction aids in the compound manufacturing process or contaminated from a reaction kettle or other manufacturing equipment.

The compound in this embodiment has a halogen element as a substituent, which improves the exposure efficiency in the lithography process, thereby improving the lithography performance. However, if metal-containing impurities remain in the system, the halogen element that is a feature of the compound in this embodiment becomes unstable, and the desired characteristics cannot be obtained, or unexpected secondary reactions such as decomposition of the resin or bond formation between resins due to the detachment of the halogen element, etc., are induced, which results in deterioration of performance in terms of sensitivity, resolution, roughness, exposure stability, defects, etc. in lithography. Due to these factors, it is preferable to reduce the metal-containing impurities. For the compound in this embodiment, there is a concern that the halogen element may be destabilized by Fe, Al, Sb, Ru, W, etc.

The residual amount of the above-mentioned metal impurities is preferably less than 1 ppm, more preferably less than 100 ppb, and even more preferably less than 50 ppb, relative to the resin. In particular, for metal species such as Fe, Al, Sb, Ru, and W, which are classified as transition metals, if the residual metal amount is 1 ppm or more, there is a concern that the interaction with the compound in this embodiment may cause the material to degenerate or deteriorate over time. In addition, if the residual metal amount is 1 ppm or more, it is not possible to sufficiently reduce the residual metal amount when preparing a resin for semiconductor processing using the prepared compound, and there is a concern that this may cause defects due to residual metals in the semiconductor manufacturing process or a decrease in yield due to performance deterioration.

The purification method is not particularly limited, but includes a step of dissolving the compound of the present embodiment in a solvent to obtain a solution (S), and a step (first extraction step) of contacting the obtained solution (S) with an acidic aqueous solution to extract impurities in the compound of the present embodiment, wherein the solvent used in the step of obtaining the solution (S) includes an organic solvent that is arbitrarily immiscible with water.
According to the above purification method, it is possible to reduce the contents of various metals that may be contained in the resin as impurities.
More specifically, the compound in the present embodiment can be dissolved in an organic solvent that is not miscible with water to obtain a solution (S), and the solution (S) can be contacted with an acidic aqueous solution to perform an extraction treatment, whereby the metal content in the solution (S) is transferred to the aqueous phase, and the organic phase and the aqueous phase are separated to obtain a resin with a reduced metal content.

The water-immiscible solvent used in the above purification method is not particularly limited, but is preferably an organic solvent that can be safely applied to the semiconductor manufacturing process, specifically an organic solvent whose solubility in water at room temperature is less than 30%, more preferably less than 20%, and particularly preferably less than 10%. The amount of the organic solvent used is preferably 1 to 100 times the total amount of the resin used.

Specific examples of solvents that are not randomly miscible with water include, but are not limited to, ethers such as diethyl ether and diisopropyl ether, esters such as ethyl acetate, n-butyl acetate, and isoamyl acetate, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-heptanone, and 2-pentanone; glycol ether acetates such as ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), and propylene glycol monoethyl ether acetate; aliphatic hydrocarbons such as n-hexane and n-heptane; aromatic hydrocarbons such as toluene and xylene; and halogenated hydrocarbons such as methylene chloride and chloroform. Among these, toluene, 2-heptanone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethyl acetate, etc. are preferred, methyl isobutyl ketone, ethyl acetate, cyclohexanone, propylene glycol monomethyl ether acetate are more preferred, and methyl isobutyl ketone and ethyl acetate are even more preferred. Methyl isobutyl ketone, ethyl acetate, etc. have a relatively high saturated solubility of the compound in this embodiment and a relatively low boiling point, so that it is possible to reduce the load in the process of industrially distilling off the solvent or removing it by drying. Each of these solvents can be used alone, or two or more of them can be mixed and used.

The acidic aqueous solution used in the above purification method is appropriately selected from among aqueous solutions in which a commonly known organic or inorganic compound is dissolved in water. Examples include, but are not limited to, mineral acid aqueous solutions in which a mineral acid such as hydrochloric acid, sulfuric acid, nitric acid, or phosphoric acid is dissolved in water, or organic acid aqueous solutions in which an organic acid such as acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, tartaric acid, citric acid, methanesulfonic acid, phenolsulfonic acid, p-toluenesulfonic acid, or trifluoroacetic acid is dissolved in water. These acidic aqueous solutions can be used alone or in combination of two or more. Among these acidic aqueous solutions, one or more mineral acid aqueous solutions selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, or one or more organic acid aqueous solutions selected from the group consisting of acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, tartaric acid, citric acid, methanesulfonic acid, phenolsulfonic acid, p-toluenesulfonic acid, and trifluoroacetic acid are preferred, and aqueous solutions of sulfuric acid, nitric acid, and carboxylic acids such as acetic acid, oxalic acid, tartaric acid, and citric acid are more preferred, and aqueous solutions of oxalic acid are even more preferred. Polycarboxylic acids such as oxalic acid, tartaric acid, and citric acid are coordinated to metal ions, and a chelating effect is generated, so that it is considered that there is a tendency to more effectively remove metals. In addition, it is preferable to use water with a low metal content, such as ion-exchanged water, in accordance with the purpose of the purification method in this embodiment.

The pH of the acidic aqueous solution used in the above purification method is not particularly limited, but it is preferable to adjust the acidity of the aqueous solution taking into consideration the effect on the resin. The pH range is usually about 0 to 5, and preferably about 0 to 3.

The amount of the acidic aqueous solution used in the above purification method is not particularly limited, but it is preferable to adjust the amount used from the viewpoint of reducing the number of extractions for metal removal and from the viewpoint of ensuring operability in consideration of the total liquid volume. From the above viewpoints, the amount of the acidic aqueous solution used is preferably 10 to 200% by mass, and more preferably 20 to 100% by mass, relative to 100% by mass of the above solution (S).

In the above purification method, the acidic aqueous solution is brought into contact with the above solution (S), thereby enabling the metal components to be extracted from the above resin in the solution (S).

In the above purification method, the solution (S) may further contain an organic solvent that is arbitrarily miscible with water. When the solution (S) contains an organic solvent that is arbitrarily miscible with water, the amount of the resin charged can be increased, and the liquid separation property is improved, and purification tends to be performed with high kettle efficiency. The method of adding the organic solvent that is arbitrarily miscible with water is not particularly limited. For example, any of the following methods may be used: adding the organic solvent to a solution containing an organic solvent in advance, adding the organic solvent to water or an acidic aqueous solution in advance, or adding the organic solvent after contacting the solution containing the organic solvent with water or an acidic aqueous solution. Among these, the method of adding the organic solvent to a solution containing an organic solvent in advance is preferable in terms of ease of operation and ease of management of the amount charged.

The organic solvent that is miscible with water and used in the above purification method is not particularly limited, but an organic solvent that can be safely applied to the semiconductor manufacturing process is preferable. The amount of the organic solvent that is miscible with water and used is not particularly limited as long as the solution phase and the aqueous phase are separated, but it is preferably 0.1 to 100 times by mass, more preferably 0.1 to 50 times by mass, and even more preferably 0.1 to 20 times by mass, relative to the total amount of the resin used.

Specific examples of organic solvents that are optionally miscible with water and used in the above purification method include, but are not limited to, ethers such as tetrahydrofuran and 1,3-dioxolane; alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone and N-methylpyrrolidone; and aliphatic hydrocarbons such as glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether (PGME), and propylene glycol monoethyl ether. Among these, N-methylpyrrolidone, propylene glycol monomethyl ether, and the like are preferred, with N-methylpyrrolidone and propylene glycol monomethyl ether being more preferred. Each of these solvents can be used alone, or two or more can be mixed together.

The temperature during the extraction process is usually in the range of 20 to 90°C, and preferably in the range of 30 to 80°C. The extraction operation is carried out, for example, by mixing thoroughly by stirring or the like, and then allowing to stand. This causes the metals contained in the solution (S) to migrate to the aqueous phase. This operation also reduces the acidity of the solution, making it possible to suppress deterioration of the resin.

The above mixed solution separates into a solution phase containing the resin and the solvent and an aqueous phase when left to stand, and the solution phase is recovered by decantation or the like. The time for standing is not particularly limited, but it is preferable to adjust the time for standing from the viewpoint of improving the separation of the solution phase containing the solvent and the aqueous phase. Usually, the time for standing is 1 minute or more, preferably 10 minutes or more, and more preferably 30 minutes or more. In addition, the extraction process may be performed only once, but it is also effective to repeat the operations of mixing, standing, and separation multiple times.

In the above purification method, it is preferable to further include a step (second extraction step) of contacting the solution phase containing the resin with water after the first extraction step to extract impurities in the resin. Specifically, for example, after the above extraction treatment is performed using an acidic aqueous solution, it is preferable to further subject the solution phase containing the resin and the solvent extracted and recovered from the aqueous solution to an extraction treatment with water. The above extraction treatment with water is not particularly limited, but can be performed, for example, by thoroughly mixing the above solution phase and water by stirring or the like, and then allowing the resulting mixed solution to stand. The mixed solution after standing is separated into a solution phase containing the above resin and the solvent and an aqueous phase, so the solution phase can be recovered by decantation or the like.
In addition, in accordance with the object of this embodiment, the water used here is preferably water with a low metal content, such as ion-exchanged water. The extraction treatment may be performed only once, but it is also effective to repeat the operations of mixing, standing, and separation several times. In addition, the conditions such as the ratio of both used in the extraction treatment, the temperature, and the time are not particularly limited, but may be the same as those in the contact treatment with the acidic aqueous solution.

Any moisture that may be mixed into the solution containing the resin and the solvent obtained in this way can be easily removed by performing an operation such as vacuum distillation. In addition, if necessary, a solvent can be added to the above solution to adjust the resin concentration to any desired concentration.

In the method for purifying the compound according to the present embodiment, the compound can also be purified by passing a solution in which the resin is dissolved in a solvent through a filter.
According to the method for purifying a substance according to the present embodiment, the content of various metals in the resin can be effectively and significantly reduced. The amount of these metal components can be measured by the method described in the Examples below.
In this embodiment, "passing through" means that the solution moves from the outside of the filter through the inside of the filter and then back to the outside of the filter, and excludes, for example, a case in which the solution is simply brought into contact with the surface of the filter, or a case in which the solution is brought into contact with the surface of the filter while moving outside the ion exchange resin (i.e., a case in which the solution is simply brought into contact).

In the purification using a filter, the filter used to remove metals from the solution containing the resin and the solvent can be one that is commercially available for liquid filtration. The filtration accuracy of the filter is not particularly limited, but the nominal pore size of the filter is preferably 0.2 μm or less, more preferably less than 0.2 μm, even more preferably less than 0.1 μm, and even more preferably less than 0.1 μm, and even more preferably 0.05 μm or less. The lower limit of the nominal pore size of the filter is not particularly limited, but is usually 0.005 μm. The nominal pore size here is the nominal pore size that indicates the separation performance of the filter, and is determined by a test method determined by the filter manufacturer, such as a bubble point test, a mercury porosimetry test, or a standard particle supplement test. When a commercially available product is used, it is the value described in the catalog data of the manufacturer. By making the nominal pore size 0.2 μm or less, the content of metals after passing the solution through the filter once can be effectively reduced. In this embodiment, in order to further reduce the content of each metal in the solution, the filter passing step may be performed two or more times.

As the form of the filter, a hollow fiber membrane filter, a membrane filter, a pleated membrane filter, and a filter filled with a filter material such as nonwoven fabric, cellulose, and diatomaceous earth can be used. Among the above, it is preferable that the filter is one or more types selected from the group consisting of a hollow fiber membrane filter, a membrane filter, and a pleated membrane filter. In addition, it is particularly preferable to use a hollow fiber membrane filter, in particular because of its high-precision filtration accuracy and its large filtration area compared to other forms.

Examples of the material of the filter include polyolefins such as polyethylene and polypropylene, polyethylene-based resins with functional groups having ion exchange capacity by graft polymerization, polar group-containing resins such as polyamide, polyester, and polyacrylonitrile, and fluorine-containing resins such as fluorinated polyethylene (PTFE). Among the above, it is preferable that the filter material is one or more selected from the group consisting of polyamide, polyolefin resin, and fluororesin. In addition, polyamide is particularly preferable from the viewpoint of reducing heavy metals such as chromium. In addition, it is preferable to use a filter material other than sintered metal material from the viewpoint of avoiding metal elution from the filter material.

Examples of polyamide-based filters (hereinafter, trademarks) include, but are not limited to, the Polyfix nylon series manufactured by Kitz Microfilter Co., Ltd., Ultipleats P-nylon 66 and Ultipore N66 manufactured by Nippon Pole Co., Ltd., and the LifeAsure PSN series and LifeAsure EF series manufactured by 3M Limited.
Examples of polyolefin filters include, but are not limited to, Ultipleats PE Clean and Ion Clean, both manufactured by Nippon Pole Co., Ltd., and Protego Series, Microguard Plus HC10, and Optimizer D, both manufactured by Nippon Entegris Co., Ltd.
Examples of polyester-based filters include, but are not limited to, Gelaflow DFE manufactured by Central Filter Kogyo Co., Ltd. and Breeze Type PMC manufactured by Nippon Filter Co., Ltd.
Examples of polyacrylonitrile filters include, but are not limited to, Ultrafilters AIP-0013D, ACP-0013D, and ACP-0053D manufactured by Advantec Toyo Co., Ltd.
Examples of fluororesin filters include, but are not limited to, Enflon HTPFR manufactured by Nippon Pole Co., Ltd., and Lifesure FA series manufactured by 3M Limited.
These filters may be used alone or in combination of two or more kinds.

The filter may also contain an ion exchanger such as a cation exchange resin, or a cationic charge regulator that generates a zeta potential in the organic solvent solution to be filtered.
Filters containing an ion exchanger include, but are not limited to, the Protego series manufactured by Nippon Entegris Co., Ltd., and Clangraft manufactured by Kurashiki Sen-i Kako Co., Ltd.
In addition, examples of filters containing substances having a positive zeta potential, such as polyamide polyamine epichlorohydrin cationic resin (hereinafter, trademarks), include, but are not limited to, Zeta Plus 40QSH and Zeta Plus 020GN manufactured by 3M Limited, and the Life Asure EF series.

[Composition containing halogen-containing polymerizable compound or (co)polymer thereof]
The composition of the present embodiment contains a halogen-containing polymerizable compound or its (co)polymer, and is particularly suitable for lithography technology. Although not particularly limited, the composition can be used for forming a film for lithography, for example, for forming a resist film (i.e., a "resist composition"). Furthermore, the composition can be used for forming an upper layer film (i.e., a "composition for forming an upper layer film"), an intermediate layer (i.e., a "composition for forming an intermediate layer"), an underlayer film (i.e., a "composition for forming an underlayer film"), etc. According to the composition of the present embodiment, a film having high sensitivity can be formed, and it is also possible to impart a good resist pattern shape.

The composition of the present embodiment can also be used as an optical component forming composition to which lithography technology is applied. In addition to being used in the form of a film or sheet, optical components are useful as plastic lenses (prism lenses, lenticular lenses, microlenses, Fresnel lenses, viewing angle control lenses, contrast enhancement lenses, etc.), retardation films, films for electromagnetic wave shielding, prisms, optical fibers, solder resists for flexible printed wiring, plating resists, interlayer insulating films for multilayer printed wiring boards, photosensitive optical waveguides, liquid crystal displays, organic electroluminescence (EL) displays, optical semiconductor (LED) elements, solid-state imaging elements, organic thin-film solar cells, dye-sensitized solar cells, and organic thin-film transistors (TFTs). The composition can be suitably used as an embedded film and planarizing film on a photodiode, which is a component of a solid-state imaging element that is particularly required to have a high refractive index, a planarizing film before and after a color filter, a microlens, a planarizing film on a microlens, and a conformal film.

The composition of the present embodiment contains a halogen-containing polymerizable compound or its (co)polymer (B), and may contain other components such as a base material (A), a solvent (S), an acid generator (C), and an acid diffusion controller (E) as necessary. Each component will be described below.

[Base material (A)]
In this embodiment, the term "substrate (A)" refers to a compound (including a resin) other than a halogen-containing polymerizable compound or its (co)polymer, and is applied as a resist for g-line, i-line, KrF excimer laser (248 nm), ArF excimer laser (193 nm), extreme ultraviolet (EUV) lithography (13.5 nm) or electron beam (EB) (for example, a substrate for lithography or a substrate for resist). Any of these substrates can be used as the substrate (A) in this embodiment without any particular limitation. Examples of the substrate (A) include phenol novolac resin, cresol novolac resin, hydroxystyrene resin, (meth)acrylic resin, hydroxystyrene-(meth)acrylic copolymer, cycloolefin-maleic anhydride copolymer, cycloolefin, vinyl ether-maleic anhydride copolymer, and inorganic resist materials having metal elements such as titanium, tin, hafnium, and zirconium, as well as derivatives thereof. Among these, from the viewpoint of the shape of the resulting resist pattern, preferred are phenol novolak resins, cresol novolak resins, hydroxystyrene resins, (meth)acrylic resins, hydroxystyrene-(meth)acrylic copolymers, and inorganic resist materials containing metal elements such as titanium, tin, hafnium, zirconium, and derivatives thereof.

The derivative is not particularly limited, but examples thereof include those into which a dissociable group has been introduced and those into which a crosslinkable group has been introduced. The derivative into which a dissociable group or a crosslinkable group has been introduced can undergo a dissociation reaction or a crosslinking reaction by the action of light, acid, or the like.

The term "dissociable group" refers to a characteristic group that cleaves to produce a functional group such as an alkali-soluble group that changes solubility. Examples of alkali-soluble groups include, but are not limited to, a phenolic hydroxyl group, a carboxyl group, a sulfonic acid group, and a hexafluoroisopropanol group, with the phenolic hydroxyl group and the carboxyl group being preferred, and the phenolic hydroxyl group being particularly preferred.

"Crosslinkable group" refers to a group that crosslinks in the presence or absence of a catalyst. Examples of crosslinkable groups include, but are not limited to, alkoxy groups having 1 to 20 carbon atoms, groups having an allyl group, groups having a (meth)acryloyl group, groups having an epoxy (meth)acryloyl group, groups having a hydroxyl group, groups having a urethane (meth)acryloyl group, groups having a glycidyl group, and groups having a vinyl-containing phenylmethyl group.

[Solvent (S)]
In the present embodiment, any known solvent can be appropriately used as long as it is capable of dissolving at least the halogen-containing polymerizable compound or the (co)polymer thereof (B). Specific examples of the solvent include, but are not limited to, 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 ether acetates 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 (PGME) and propylene glycol monoethyl ether; esters such as methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, and n-amyl lactate. esters; aliphatic carboxylic acid esters such as methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, n-amyl acetate, n-hexyl acetate, methyl propionate, and ethyl propionate; methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl 3-methoxy-2-methylpropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, butyl 3-methoxy-3-methylpropionate, 3-meth Examples of the solvent include, but are not limited to, other esters such as butyl oxy-3-methylbutyrate, methyl acetoacetate, methyl pyruvate, and ethyl pyruvate; aromatic hydrocarbons such as toluene and xylene; ketones such as acetone, 2-butanone, 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; and lactones such as γ-lactone. The solvent used in the present embodiment is preferably a safe solvent, and more preferably at least one selected from PGMEA, PGME, CHN, CPN, 2-heptanone, anisole, butyl acetate, and ethyl lactate, and even more preferably at least one selected from PGMEA, PGME, CHN, CPN, and ethyl lactate.

In this embodiment, the amount of solid components and the amount of solvent are not particularly limited, but it is preferable that the amount of solid components is 1 to 80% by mass and the amount of solvent is 20 to 99% by mass, more preferably 1 to 50% by mass and the amount of solvent is 50 to 99% by mass, even more preferably 2 to 40% by mass and the amount of solvent is 60 to 98% by mass, and particularly preferably 2 to 10% by mass and the amount of solid components is 90 to 98% by mass.

[Acid Generator (C)]
The composition of the present embodiment preferably contains one or more acid generators (C) that generate an acid directly or indirectly upon irradiation with any radiation selected from visible light, ultraviolet light, excimer laser, electron beam, extreme ultraviolet light (EUV), X-rays, and ion beams. The acid generator (C) is not particularly limited, but for example, those described in International Publication WO2013/024778 can be used. The acid generators (C) can be used alone or in combination of two or more.

The amount of the acid generator (C) used is preferably 0.001 to 49% by mass, more preferably 1 to 40% by mass, even more preferably 3 to 30% by mass, and particularly preferably 10 to 25% by mass, of the total mass of the solid components. By using the acid generator (C) within the above range, a pattern profile with high sensitivity and low edge roughness tends to be obtained. In this embodiment, the method of generating the acid is not particularly limited as long as an acid is generated in the system. If an excimer laser is used instead of ultraviolet rays such as g-rays and i-rays, finer processing is possible, and further finer processing is possible if an electron beam, extreme ultraviolet rays, X-rays, or ion beams are used as high-energy rays.

[Acid Diffusion Controller (E)]
In this embodiment, an acid diffusion controller (E) having the action of controlling the diffusion of the acid generated from the acid generator by radiation exposure in the resist film and preventing undesirable chemical reactions in unexposed regions may be blended in the composition. By using the acid diffusion controller (E), the storage stability of the composition of this embodiment tends to be improved. In addition, by using the acid diffusion controller (E), the resolution of the film formed using the composition of this embodiment can be improved, and the change in line width of the resist pattern due to the variation between the delay time before radiation exposure and the delay time after radiation exposure can be suppressed, and the process stability tends to be excellent. The acid diffusion controller (E) is not particularly limited, and examples thereof include radiation decomposable basic compounds such as nitrogen atom-containing basic compounds, basic sulfonium compounds, and basic iodonium compounds.

The acid diffusion control agent (E) is not particularly limited, but for example, those described in International Publication WO2013/024778 can be used. The acid diffusion control agent (E) can be used alone or in combination of two or more kinds.

The amount of the acid diffusion control agent (E) is preferably 0.001 to 49% by mass, more preferably 0.01 to 10% by mass, even more preferably 0.01 to 5% by mass, and particularly preferably 0.01 to 3% by mass, based on the total mass of the solid components. When the amount of the acid diffusion control agent (E) is within the above range, it tends to be possible to prevent a decrease in resolution, deterioration of the pattern shape, dimensional fidelity, etc. Furthermore, even if the waiting time from electron beam irradiation to heating after radiation irradiation is long, it is possible to suppress deterioration of the shape of the upper layer of the pattern. Furthermore, when the amount is 10% by mass or less, it tends to be possible to prevent a decrease in sensitivity, developability of the unexposed part, etc. Furthermore, by using such an acid diffusion control agent, the storage stability of the resist composition is improved, and the resolution is improved, and changes in the line width of the resist pattern due to fluctuations in the waiting time before radiation irradiation and the waiting time after radiation irradiation can be suppressed, and the process stability tends to be excellent.

[Other components (F)]
To the composition of the present embodiment, as other component (F), one or more of various additives such as a crosslinking agent, a dissolution promoter, a dissolution control agent, a sensitizer, a surfactant, and an organic carboxylic acid, a phosphorus oxoacid, or a derivative thereof may be added as necessary.

(Crosslinking Agent)
In this embodiment, the composition may contain one or more crosslinking agents. The crosslinking agent means a compound capable of crosslinking at least the substrate (A) or the halogen-containing polymerizable compound or its (co)polymer (B). The crosslinking agent is preferably an acid crosslinking agent capable of intramolecularly or intermolecularly crosslinking the substrate (A) in the presence of the acid generated from the acid generator (C). Such an acid crosslinking agent may, for example, be a compound having one or more groups (hereinafter referred to as "crosslinkable groups") capable of crosslinking the substrate (A).

Examples of the crosslinkable group include (i) hydroxyalkyl groups such as hydroxy (alkyl groups having 1 to 6 carbon atoms), alkoxy (alkyl groups having 1 to 6 carbon atoms), and acetoxy (alkyl groups having 1 to 6 carbon atoms), or groups derived therefrom; (ii) carbonyl groups such as formyl and carboxy (alkyl groups having 1 to 6 carbon atoms), or groups derived therefrom; (iii) dimethylaminomethyl groups, diethylaminomethyl groups, dimethylolaminomethyl groups, diethylolaminomethyl groups, and dimethylolaminomethyl groups. Examples of the crosslinkable group include a nitrogen-containing group such as a methyl group or a morpholinomethyl group; (iv) a glycidyl group-containing group such as a glycidyl ether group, a glycidyl ester group or a glycidylamino group; (v) a group derived from an aromatic group such as an allyloxy (an alkyl group having 1 to 6 carbon atoms) having 1 to 6 carbon atoms or an aralkyloxy (an alkyl group having 1 to 6 carbon atoms) having 1 to 6 carbon atoms, such as a benzyloxymethyl group or a benzoyloxymethyl group; and (vi) a polymerizable multiple bond-containing group such as a vinyl group or an isopropenyl group. As the crosslinkable group of the crosslinking agent in this embodiment, a hydroxyalkyl group and an alkoxyalkyl group are preferred, and an alkoxymethyl group is particularly preferred.

The crosslinking agent having a crosslinkable group is not particularly limited, but for example, the acid crosslinking agent described in International Publication WO2013/024778 can be used. The crosslinking agents can be used alone or in combination.

In this embodiment, the amount of crosslinking agent is preferably 50% by mass or less of the total mass of the solid components, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 20% by mass or less.

(Solubility enhancer)
The dissolution promoter is a component that has the effect of increasing the solubility of the solid component in the developer when the solubility is too low, and appropriately increasing the dissolution rate of the compound during development. The dissolution promoter is preferably a low molecular weight one, and examples thereof include low molecular weight phenolic compounds. Examples of low molecular weight phenolic compounds include bisphenols, tris(hydroxyphenyl)methane, etc. These dissolution promoters can be used alone or in combination of two or more kinds.

The amount of the dissolution promoter is adjusted appropriately depending on the type of solid component used, but is preferably 0 to 49% by mass, more preferably 0 to 5% by mass, even more preferably 0 to 1% by mass, and particularly preferably 0% by mass, of the total mass of the solid components.

(Dissolution Control Agent)
The dissolution controller is a component that has the effect of controlling the solubility of a solid component in a developer when the solubility of the solid component is too high in the developer, thereby appropriately reducing the dissolution rate during development. As such a dissolution controller, it is preferable that the dissolution controller does not undergo chemical changes during steps such as baking, irradiation, and development of the resist film.

Examples of dissolution control agents include, but are not limited to, aromatic hydrocarbons such as phenanthrene, anthracene, and acenaphthene; ketones such as acetophenone, benzophenone, and phenyl naphthyl ketone; and sulfones such as methyl phenyl sulfone, diphenyl sulfone, and dinaphthyl sulfone. These dissolution control agents can be used alone or in combination of two or more.

The amount of dissolution inhibitor is adjusted appropriately depending on the type of compound used, but is preferably 0 to 49% by mass of the total solid component mass, more preferably 0 to 5% by mass, even more preferably 0 to 1% by mass, and particularly preferably 0% by mass.

(Sensitizer)
The sensitizer is a component that absorbs the energy of the irradiated radiation, transfers the energy to the acid generator (C), and thereby increases the amount of acid generated, thereby improving the apparent sensitivity of the resist. Examples of such sensitizers include, but are not limited to, benzophenones, biacetyls, pyrenes, phenothiazines, fluorenes, etc. These sensitizers can be used alone or in combination.

The amount of sensitizer used is adjusted appropriately depending on the type of compound used, but is preferably 0 to 49% by mass of the total solid component mass, more preferably 0 to 5% by mass, even more preferably 0 to 1% by mass, and particularly preferably 0% by mass.

(Surfactant)
The surfactant is a component that has the effect of improving the coatability and striation of the composition of this embodiment, the developability of the resist, and the like. The surfactant may be any of anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. A preferred surfactant is a nonionic surfactant. The nonionic surfactant has good affinity with the solvent used in the production of the composition of this embodiment, and can further enhance the effect of the composition of this embodiment. Examples of the nonionic surfactant include, but are not limited to, polyoxyethylene higher alkyl ethers, polyoxyethylene higher alkyl phenyl ethers, and higher fatty acid diesters of polyethylene glycol. Examples of commercially available products of these surfactants include, under the trade names below, Eftop (manufactured by Gemco), Megafac (manufactured by Dainippon Ink and Chemicals, Inc.), Fluorad (manufactured by Sumitomo ThreeM), Asahi Guard, Surflon (all manufactured by Asahi Glass Co., Ltd.), Pepol (manufactured by Toho Chemical Industry Co., Ltd.), KP (manufactured by Shin-Etsu Chemical Co., Ltd.), and Polyfluor (manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.).

The amount of surfactant to be used is adjusted appropriately depending on the type of solid component used, but is preferably 0 to 49% by mass, more preferably 0 to 5% by mass, even more preferably 0 to 1% by mass, and particularly preferably 0% by mass, of the total mass of the solid components.

(Organic carboxylic acid or phosphorus oxoacid or its derivative)
For the purpose of preventing deterioration in sensitivity or improving resist pattern shape, post-deposition stability, etc., an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof may be further contained as an optional component. The organic carboxylic acid or the oxo acid of phosphorus or a derivative thereof may be used in combination with an acid diffusion controller, or may be used alone. Suitable examples of the organic carboxylic acid include malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid. Suitable examples of the oxo acid of phosphorus or a derivative thereof include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester, and other phosphoric acid or ester derivatives thereof, phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester, and other phosphonic acid or ester derivatives thereof, phosphinic acid, phenylphosphinic acid, and other phosphinic acid and ester derivatives thereof, and among these, phosphonic acid is particularly preferred.

The organic carboxylic acid or phosphorus oxoacid or its derivative may be used alone or in combination of two or more. The amount of organic carboxylic acid or phosphorus oxoacid or its derivative is adjusted appropriately depending on the type of compound used, but is preferably 0 to 49% by mass, more preferably 0 to 5% by mass, even more preferably 0 to 1% by mass, and particularly preferably 0% by mass, of the total mass of the solid components.

[Other additives]
Furthermore, the composition of the present embodiment may contain one or more additives other than the above-mentioned components, as necessary. Examples of such additives include dyes, pigments, and adhesion aids. For example, the incorporation of a dye or pigment is preferable because it can visualize the latent image of the exposed area and mitigate the effect of halation during exposure. In addition, the incorporation of an adhesion aid is preferable because it can improve adhesion to the substrate. Furthermore, examples of other additives include antihalation agents, storage stabilizers, defoamers, shape improvers, and the like, specifically 4-hydroxy-4'-methylchalcone.

In the composition of this embodiment, the total amount of optional component (F) can be 0 to 99 mass% of the total mass of the solid components, preferably 0 to 49 mass%, more preferably 0 to 10 mass%, even more preferably 0 to 5 mass%, even more preferably 0 to 1 mass%, and particularly preferably 0 mass%.

To form a resist pattern from the composition of the present invention, the composition solution is applied to a substrate such as a silicon wafer, metal, plastic, glass, or ceramic by a suitable coating means such as a spin coater, dip coater, or roller coater to form a resist film, which is optionally heated at a temperature of about 50°C to 200°C beforehand, and then exposed through a predetermined mask pattern. The thickness of the coating film is, for example, about 0.1 to 20 μm, preferably about 0.3 to 2 μm. For exposure, light rays of various wavelengths, such as ultraviolet rays and X-rays, can be used. For example, as a light source, far ultraviolet rays such as F2 excimer laser (wavelength 157 nm), ArF excimer laser (wavelength 193 nm), and KrF excimer laser (wavelength 248 nm), extreme ultraviolet rays (wavelength 13n), X-rays, electron beams, etc. are appropriately selected and used. In addition, exposure conditions such as the exposure dose are appropriately selected depending on the blending composition of the above-mentioned resin and/or compound, the type of each additive, etc.

In the present invention, in order to stably form a highly accurate fine pattern, it is preferable to perform a heat treatment at a temperature of 50 to 200°C for 30 seconds or more after exposure. In this case, if the temperature is less than 50°C, there is a risk of widening the variation in sensitivity depending on the type of substrate. Thereafter, the desired resist pattern is formed by developing with an alkaline developer, usually at 10 to 50°C for 10 to 200 seconds, preferably at 20 to 25°C for 15 to 90 seconds.

The alkaline developer is, for example, an alkaline aqueous solution in which an alkaline compound such as an alkali metal hydroxide, aqueous ammonia, alkylamines, alkanolamines, heterocyclic amines, tetraalkylammonium hydroxides, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, or 1,5-diazabicyclo-[4.3.0]-5-nonene is dissolved to a concentration of usually 1 to 10% by weight, preferably 1 to 3% by weight. In addition, a water-soluble organic solvent or a surfactant can be appropriately added to the developer consisting of the alkaline aqueous solution.

The composition of this embodiment can also be used as a patterning material for lithography applications. The lithography process can be used for various applications, such as semiconductors, liquid crystal display panels, display panels using OLEDs, power devices, CCDs and other sensors. In particular, for integrated circuits of semiconductors and devices, in the process of forming device elements on a silicon wafer, a pattern is formed on the insulating film on the substrate side by etching based on a pattern formed on the upper surface side of an insulating layer such as a silicon oxide film or other oxide film using the composition of this embodiment, and further, a metal film or semiconductor material is laminated based on the formed insulating film pattern to form a circuit pattern, thereby constructing semiconductor elements and other devices. The composition of this embodiment can be suitably used.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[Measurement method]
(1) Compound Structure The compound structure was confirmed by ¹ H-NMR measurement using an Advance 600II spectrometer manufactured by Bruker under the following conditions.
Frequency: 400MHz
Solvent: CDCl ₃ or d ₆ -DMSO
Internal standard: TMS
Measurement temperature: 23℃

[Inorganic element content]
The metal contents of the compounds prepared in the examples and comparative examples were measured using an inorganic elemental analysis (ICP-AES/ICP-MS) device "AG8900" (product name, manufactured by Agilent Technologies, Inc.).

(Synthesis Example 1-1) Synthesis of M1 128g (0.78mol) of calcium chloride and 91.3g (2.4mol) _{of NaBH4} were dissolved in 2.8L of ethanol, and 410g (1.1mol) of 4-hydroxy-3,5-diiodobenzaldehyde was added thereto under ice cooling. After stirring and reacting for 18 hours at 25°C, 10L of water was added and the pH was adjusted to 2.5 with hydrochloric acid. The precipitate was filtered, washed with water, and then dried to obtain 401g (yield 97%) of 4-hydroxy-3,5-diiodobenzyl alcohol shown below.

400 g (1.06 mol) of 4-hydroxy-3,5-diiodobenzyl alcohol obtained above was dissolved in 2.8 L of toluene, and 1832 g (21.2 mol) of methacrylic acid, 40 g (0.21 mol) of paratoluenesulfonic acid monohydrate, and 26 mg (0.02 mmol) of 4-methoxyphenol were added and stirred for 2 hours under reflux at 110° C. After the reaction, 4 L of water was added to dry the organic layer, which was then recrystallized twice with hexane to obtain 158 g (yield 33%) of the target product M1 shown below.

(Synthesis Example 2-1) Synthesis of M2
90g (0.24mol) of 3,5-diiodosalicylaldehyde was dissolved in 900ml of methanol, and 22.8g (0.60mol) _{of NaBH4} was added at 10℃ or less. The mixture was then stirred for 3 hours under ice cooling, and then stirred for 16 hours at 25℃ to react, and the methanol was distilled off under reduced pressure to concentrate. Water and ethyl acetate were added to the concentrate, and the organic phase was extracted. Magnesium sulfate was added to this organic phase to dry it, and the solvent was distilled off under reduced pressure to obtain a crude product of 2-hydroxy-3,5-diiodobenzyl alcohol. The obtained crude product of 2-hydroxy-3,5-diiodobenzyl alcohol was purified by column chromatography to obtain 82.5g (yield 91%) of 2-hydroxy-3,5-diiodobenzyl alcohol shown below.

10 g (27 mmol) of 2-hydroxy-3,5-diiodobenzyl alcohol obtained above was dissolved in 100 mL of dichloromethane, and 3.1 g (39 mmol) of pyridine was added under ice cooling, and 8.2 g (54 mmol) of methacrylic anhydride was added dropwise. The mixture was then stirred for 4 hours under ice cooling and for 24 hours at room temperature to react. After the reaction was completed, water was added to the reaction solution, which was then washed with an aqueous solution of sodium hydrogen carbonate. Magnesium sulfate was added to the organic phase to dry it, and the mixture was concentrated and purified by column chromatography to obtain 9 g (yield 88%) of the target product M2 shown below.

The following compounds M3 to M5, MRA1, MRA3, and MRA5 were synthesized using the corresponding raw materials according to the method of Synthesis Example 1-1.
The following compounds MRB1, MRB3, MRB5, MRC1, MRC3, and MRC5 were synthesized according to the method of Synthesis Example 1-1, using the corresponding raw materials and appropriately reducing the amount of methacrylic acid used.

(Synthesis Example 3-1) Synthesis of MAD1 1.84 g (10 mmol) of adamantyltriol, 3.0 g (20 mmol) of NaI, 2.18 g (20 mmol) of chlorotrimethylsilyl, and 15.7 g of acetonitrile were added to a 200 mL flask, and refluxed at 80° C. for 5 hours. After cooling to room temperature, 21.2 mL of a 6% by mass aqueous solution of Na2S2O3 was added. Furthermore, extraction of the organic phase was performed five times with 80 mL of diethyl ether, and the obtained organic phase was concentrated under reduced pressure to obtain 1.68 g of a pale yellow solid (yield 57%).

In a 200 mL flask, 1.68 g (5.7 mmol) of the monoiodoadamantanediol obtained above was dissolved in 150 mL of dichloromethane, and 1.56 g (15 mmol) of methacrylic acid chloride and 0.61 g (6 mmol) of triethylamine were added under a temperature condition of 0° C., and the mixture was stirred for 5 hours at 0° C. After the reaction, separation washing was performed with 50 mL of a 1% aqueous hydrochloric acid solution, and then 50 mL of water was added for separation treatment, magnesium sulfate was added to the organic layer and dried, and then the filtrate was collected and concentrated under reduced pressure to obtain 1.96 g (yield 79%) of the target product MAD1 shown below.

(Synthesis Example 1) Synthesis of M1 resin 1.5 g of M1, 3.0 g of 2-methyl-2-adamantyl methacrylate, 2.0 g of γ-butyrolactone methacrylate, and 1.5 g of hydroxyadamantyl methacrylate were dissolved in 45 mL of tetrahydrofuran, and 0.20 g of azobisisobutyronitrile was added. After refluxing for 12 hours, the reaction solution was dropped into 2 liters of n-heptane. The precipitated resin was filtered and dried under reduced pressure to obtain a white powder-like resin represented by the following chemical formula (P-MAC-0I). The molecular weight (Mw) of this resin was 12,000, and the dispersity (Mw/Mn) was 1.90. In addition, as a result of measuring ¹³ C-NMR, the composition ratio (molar ratio) in the following chemical formula (P-MAC-0I) was a:b:c:d=40:30:15:15. It should be noted that the following chemical formula (P-MAC-0I) is simply shown to indicate the ratio of each constituent unit, but P-MAC-0I is not a block copolymer in which each constituent unit forms an independent block.

(Synthesis Examples 2 to 6, Synthesis Comparative Examples 1 to 9)
Various resins were prepared in the same manner as in Synthesis Example 1, except that M2 to 5, MRA1, MRA3, MRA5, MRB1, MRB3, MRB5, MRC1, MRC3, MRC5, and MAD1 were used instead of M1, respectively.

(EUV Sensitivity Evaluation)
A resin solution containing the resin prepared in the Synthesis Example or the Synthesis Comparative Example was applied onto a silicon wafer and baked for 60 seconds at 110° C. to form a photoresist layer with a film thickness of 100 nm. Here, the resin solution was prepared by mixing 5 parts by mass of the resin prepared in the Synthesis Example or the Synthesis Comparative Example, 1 part by mass of triphenylsulfonium nonafluoromethanesulfonate, 0.2 parts by mass of tributylamine, 80 parts by mass of PGMEA, and 12 parts by mass of PGME.
Next, a maskless shot exposure was performed with an EUV exposure device (LithoTech Japan Co., Ltd.; EUVES-7000) in which the exposure dose was increased from 1 mJ/cm2 to 80 mJ/cm2 in increments of 1 mJ/cm2, followed by baking (PEB) at 110°C for 90 seconds and developing with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution for 60 seconds to obtain a wafer in which 80 shots of shot exposure were performed on the wafer. For each of the obtained shot exposure areas, the film thickness was measured using an interference film thickness meter, profile data of the film thickness relative to the exposure dose was obtained, and the exposure dose at which the slope of the film thickness variation relative to the exposure dose was the largest was calculated as a sensitivity value (mJ/cm2), which was used as an index of the EUV sensitivity of the resist.

(EB Pattern Evaluation)
A resin solution containing the resin prepared in the Synthesis Example or the Synthesis Comparative Example was applied onto a silicon wafer and baked for 60 seconds at 110 to 130° C. to form a photoresist layer with a film thickness of 100 nm. Here, the resin solution was prepared by mixing 5 parts by mass of the resin prepared in the Synthesis Example or the Synthesis Comparative Example, 1 part by mass of triphenylsulfonium nonafluoromethanesulfonate, 0.1 part by mass of tributylamine, and 92 parts by mass of PGMEA.
Next, the pattern was exposed to light using an electron beam lithography system (ELS-7500, 50 keV, manufactured by Elionix), baked at 115° C. for 90 seconds (PEB), and developed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 seconds to obtain a positive pattern. The exposure dose was adjusted to obtain a line and space with a half pitch of 20 nm.
For the obtained pattern, 80 pattern images were taken at a magnification of 100,000 times using S-4800 (manufactured by Hitachi, Ltd.), the number of pattern collapses was counted, and evaluation was made from the total amount of pattern collapse.

(Evaluation of sensitivity over time)
The prepared resin solution was subjected to forced aging treatment under light-shielded conditions at 40° C. for 240 hours, and the solution after aging was similarly subjected to an EUV sensitivity evaluation, and an evaluation was made according to the amount of change in sensitivity.

(Aging Roughness Evaluation)
The prepared resin solution was subjected to forced aging treatment under the condition of 40°C/240 hours under light-shielded conditions, and the EB pattern evaluation was performed on the solution after the aging treatment in the same manner, and a pattern image was obtained by SEM in the same manner, and roughness and residue (scum) between patterns were counted. Note that, as the developer, a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution was used as an alkaline developer to form a PTI (positive) pattern and perform PTI roughness evaluation. In addition, organic solvent development was performed using butyl acetate as the developer, and an NTI (negative) pattern was formed and performed NTI scum evaluation.

As described above, it has been found that by using the halogen-containing polymerizable compound or its polymer of this embodiment, a resin liquid for lithography that is excellent in terms of defects and performance over time can be created.

<Evaluation of etching defects in laminated films>
The quality of the resin prepared using the compound of the present invention obtained in the synthesis example was evaluated before and after purification. That is, the resin film formed on a wafer using the resin prepared using the compound of the present invention was transferred to the substrate side by etching, and then the defects were evaluated.
A 12-inch silicon wafer was subjected to thermal oxidation treatment to obtain a substrate having a silicon oxide film with a thickness of 100 nm. On the substrate, a resin solution made using the compound of the present invention was spin-coated under adjusted conditions so as to form a film with a thickness of 100 nm, and then baked at 150°C for 1 minute, followed by baking at 350°C for 1 minute, to produce a laminated substrate in which the resin made using the compound of the present invention was laminated on the silicon with a thermal oxide film.
The resin film was etched using a TELIUS (Tokyo Electron Ltd.) etching device under the condition of CF4/O2/Ar to expose the substrate on the oxide film surface. Further, an etching process was performed under the condition of etching the oxide film by 100 nm with a gas composition ratio of CF4/Ar to produce an etched wafer.
The number of defects of 19 nm or more in size was measured for the prepared etched wafer using a defect inspection device SP5 (manufactured by KLA-Tencor Corporation), and this was used to evaluate defects due to the etching process in the laminated film.

(Example E01) Purification of M1 resin with acid In a 1000 mL capacity four-neck flask (bottom-opening type), 150 g of a solution (10 mass%) obtained by dissolving the M1 resin obtained in Synthesis Example 1 in PGMEA was charged, and heated to 80 ° C. while stirring. Next, 37.5 g of an aqueous oxalic acid solution (pH 1.3) was added, stirred for 5 minutes, and then allowed to stand for 30 minutes. As a result, the oil phase and the aqueous phase were separated, and the aqueous phase was removed. After repeating this operation once, 37.5 g of ultrapure water was charged into the obtained oil phase, stirred for 5 minutes, and then allowed to stand for 30 minutes, and the aqueous phase was removed. After repeating this operation three times, the flask was heated to 80 ° C. while reducing the pressure in the flask to 200 hPa or less, and the residual water and PGMEA were concentrated and distilled off. Thereafter, the solution was diluted with EL grade PGMEA (a reagent manufactured by Kanto Chemical Co., Ltd.) and the concentration was adjusted to 10 mass %, thereby obtaining a PGMEA solution of M1 resin with a reduced metal content. The solution containing the resin prepared using the compound of the present invention was filtered under a condition of 0.5 MPa using a UPE filter having a nominal pore size of 3 nm manufactured by Nippon Entegris Co., Ltd. to prepare a solution sample, and then an evaluation of etching defects in the laminated film was performed.

(Example E02) Purification of M2 resin with acid In a 1000 mL capacity four-neck flask (bottom-opening type), 140 g of a solution (10 mass%) obtained by dissolving the M2 resin obtained in Synthesis Example 2 in PGMEA was charged and heated to 60 ° C. while stirring. Next, 37.5 g of an aqueous oxalic acid solution (pH 1.3) was added, stirred for 5 minutes, and then allowed to stand for 30 minutes. As a result, the oil phase and the aqueous phase were separated, and the aqueous phase was removed. After repeating this operation once, 37.5 g of ultrapure water was charged into the obtained oil phase, stirred for 5 minutes, and then allowed to stand for 30 minutes, and the aqueous phase was removed. After repeating this operation three times, the flask was heated to 80 ° C. while reducing the pressure in the flask to 200 hPa or less, and the residual water and PGMEA were concentrated and distilled off. Thereafter, the solution was diluted with EL grade PGMEA (a reagent manufactured by Kanto Chemical Co., Ltd.) and the concentration was adjusted to 10 mass %, thereby obtaining a PGMEA solution of M2 resin with a reduced metal content. The solution containing the resin prepared using the compound of the present invention was filtered under a condition of 0.5 MPa using a UPE filter having a nominal pore size of 3 nm manufactured by Nippon Entegris Co., Ltd. to prepare a solution sample, and then an etching defect evaluation was performed on the laminated film.

(Example E03) Purification by passing through a filter In a class 1000 clean booth, 500 g of a 10% by mass solution of the M1 resin obtained in Synthesis Example 1 dissolved in propylene glycol monomethyl ether (PGME) was charged into a 1000 mL capacity four-neck flask (bottom-opening type), and then the air inside the vessel was removed under reduced pressure, and nitrogen gas was introduced to return to atmospheric pressure, and the oxygen concentration inside was adjusted to less than 1% under aeration of nitrogen gas at 100 mL per minute, and then heated to 30 ° C. with stirring. The above solution was extracted from the bottom-opening valve, and passed through a nylon hollow fiber membrane filter (manufactured by Kitz Micro Filter Co., Ltd., product name: Polyfix Nylon Series) with a nominal pore size of 0.01 μm at a flow rate of 100 mL per minute with a diaphragm pump by pressure filtration so that the filtration pressure was 0.5 MPa. The resin solution after filtration was diluted with EL grade PGMEA (a reagent manufactured by Kanto Chemical Co., Ltd.) and the concentration was adjusted to 10% by mass, thereby obtaining a PGMEA solution of M1 resin with a reduced metal content. The solution containing the resin prepared using the compound of the present invention was filtered under a condition of 0.5 MPa using a UPE filter with a nominal pore size of 3 nm manufactured by Nippon Integris Co., Ltd. to prepare a solution sample, and then an etching defect evaluation was performed on the laminated film. The oxygen concentration was measured using an oxygen concentration meter "OM-25MF10" manufactured by AS ONE Corporation (the same applies below).

(Example E04)
As a purification step using a filter, IONKLEEN manufactured by Nippon Pall, a nylon filter manufactured by Nippon Pall, and a UPE filter having a nominal pore size of 3 nm manufactured by Nippon Integris were connected in series in this order to construct a filter line. Except for using the prepared filter line instead of a 0.1 μm nylon hollow fiber membrane filter, the liquid was passed through by pressure filtration so that the filtration pressure was 0.5 MPa in the same manner as in Example E03. The solution was diluted with EL grade PGMEA (a reagent manufactured by Kanto Chemical Co., Ltd.) and the concentration was adjusted to 10 mass%, thereby obtaining a PGMEA solution of M1 resin with a reduced metal content. The solution containing the resin prepared using the compound of the present invention was pressure-filtered through a UPE filter having a nominal pore size of 3 nm manufactured by Nippon Integris Co., Ltd. so that the filtration pressure was 0.5 MPa, and then an etching defect evaluation was performed on the laminated film.

(Example E05)
The solution sample prepared in Example E01 was further subjected to pressure filtration using the filter line prepared in Example E04 so that the filtration pressure was 0.5 MPa to prepare a solution sample, and then an evaluation of etching defects in the laminated film was performed.

(Example E06)
The M3 resin produced in (Synthesis Example 3) was purified in the same manner as in Example E05 to produce a solution sample, and then an etching defect evaluation was performed on the laminated film.

(Example E07)
The M4 resin produced in (Synthesis Example 4) was purified in the same manner as in Example E05 to produce a solution sample, and then an etching defect evaluation was performed on the laminated film.

(Example E08)
The M5 resin produced in (Synthesis Example 5) was purified in the same manner as in Example E05 to produce a solution sample, and then an etching defect evaluation was performed on the laminated film.

(Example E09)
The MAD1 resin produced in (Synthesis Example 6) was purified in the same manner as in Example E01 to produce a solution sample, and then an etching defect evaluation was performed on the laminated film.

(Example E10)
The MAD1 resin produced in (Synthesis Example 6) was purified in the same manner as in Example E01 to produce a solution sample, and then an etching defect evaluation was performed on the laminated film.

(Synthesis Example F01)
For the synthesized compound M1, purification treatment of each raw material was additionally carried out before the synthesis of the polymer. Using ethyl acetate (PrimePure manufactured by Kanto Chemical Co., Ltd.) as a solvent, a 10% by mass ethyl acetate solution of compound M1 was prepared by dissolving compound M1. For the purpose of removing metal impurities, an ion exchange resin "AMBERLYST MSPS2-1.DRY" (product name, manufactured by Organo Corporation) was immersed in ethyl acetate (PrimePure manufactured by Kanto Chemical Co., Ltd.), stirred for 1 hour, and then washed 10 times by a method of removing the solvent, to wash the ion exchange resin. The washed ion exchange resin was added to the above ethyl acetate solution of compound M1 so that the mass was the same as that of the resin solid content, and the mixture was stirred at room temperature for one day, and then washed three times by a method of performing an ion exchange treatment by filtering out the ion exchange resin, to prepare an ethyl acetate solution of ion-exchanged compound M1. Furthermore, the same treatment was performed on other monomers to prepare an ethyl acetate solution containing ion-exchanged monomers. Using the obtained ion-exchanged monomer-containing ethyl acetate solution, and using electronic grade Pruimepure manufactured by Kanto Chemical Co., Ltd. as a solvent such as n-heptane and tetrahydrofuran, and further using equipment in which all reaction vessels such as flasks were immersed in nitric acid for one day and then washed with ultrapure water, a compound represented by the above-mentioned chemical formula (P-MAC-0I) was obtained according to the same scheme as in Synthesis Example 1. Furthermore, in the post-synthesis treatment, a purification treatment was performed using a 5 nm nylon filter (manufactured by Pall) and a 15 nm PTFE filter (manufactured by Entegris) in this order, and then a white powder-like polymer (M1-CL resin) (the chemical structure is a polymer represented by the formula (P-MAC-0I)) was obtained by drying under reduced pressure. The inorganic element content of the polymer was measured by the above-mentioned method, and the results are shown in Table 3.

(Synthesis Examples F02 to F06)
Various polymers (M2-CL resin to M5-CL resin, MDA1-CL resin) were prepared in the same manner as in Synthesis Example 1, except that M2 to M5 and MAD1 were used instead of M1, respectively.

The polymer thus produced was subjected to metal content and PE-CVD defect evaluation in the same manner as in Example E01.

According to the present invention, it is possible to provide a compound and composition capable of forming a film having high resolution and sensitivity, as well as a method for forming a resist pattern and a method for forming an insulating film using the same.

Claims (12)

A (co)polymer having a structural unit derived from a compound having one or more halogens and two or more substituents having an unsaturated double bond;
A composition for forming a resist film, comprising :
The (co)polymer further comprises a structural unit having a functional group whose solubility in an alkaline developer is improved by the action of an acid or a base . The composition according to claim 1 , wherein the compound is represented by the following general formula (A):
(In formula (A),
R ¹ , R ² , and R ³ each independently represent a hydrogen atom, a halogen, a linear organic group having 1 to 20 carbon atoms, a branched organic group having 3 to 20 carbon atoms, or a cyclic organic group having 3 to 20 carbon atoms;
L represents a divalent linking group;
A represents an organic group having 1 to 30 carbon atoms;
X represents Cl, Br, or I, or a hydrocarbon group having 1 to 30 carbon atoms which contains a halogen atom selected from the group consisting of Cl, Br, and I and is bonded to A via a single bond, an ester group, an ether group, an amide group, an imide group, a urethane group, a urea group, a thioether group, a phosphine group, or a phosphate ester group;
n ⁰ represents an integer from 2 to 5;
ⁿ² represents an integer of 1 to 5. The composition according to claim 2 , wherein general formula (A) is represented by general formula (1):
(In formula (1),
R ¹ represents a hydrogen atom, a halogen atom or a methyl group;
R ⁴ each independently represents a hydrogen atom, a linear organic group having 1 to 20 carbon atoms, a branched organic group having 3 to 20 carbon atoms, or a cyclic organic group having 3 to 20 carbon atoms;
A represents an organic group having 1 to 30 carbon atoms;
n ⁰ represents an integer from 2 to 5;
ⁿ¹ represents 0 or 1;
ⁿ² represents an integer of 1 to 5. The composition of claim 2 or 3, wherein A contains an aromatic ring. 5. The composition according to claim 1, wherein the (co)polymer has a content of Fe, Al, Sb, Ru and W of less than 1 ppm. A composition for forming a resist film, comprising a compound having one or more halogens and two or more substituents having an unsaturated double bond, and/or a (co)polymer having a structural unit derived from the compound,
The composition further comprising an acid generator, a photobase generator, or a base compound . A step of depositing a composition for forming a resist film on a wafer, the composition comprising a compound having one or more halogens and two or more substituents having an unsaturated double bond, and/or a (co)polymer having a structural unit derived from the compound;
forming an optical image as a pattern on a resist film on a wafer by exposure; and forming a resist pattern based on the optical image by development.
A pattern forming method comprising the steps of: A method for forming an insulating film, comprising the method according to claim 7 . a structural unit derived from a compound having one or more halogens and two or more substituents having an unsaturated double bond, and a structural unit having a functional group whose solubility in an alkaline developer is improved by the action of an acid or a base,
A copolymer having the formula: a compound having one or more halogens and two or more substituents having an unsaturated double bond, and/or a (co)polymer having a structural unit derived from the compound, and an acid generator, a photobase generator, or a base compound,
A resist composition comprising: A step of forming a film of the resist composition according to claim 10 on a wafer;
forming an optical image as a pattern on a resist film on a wafer by exposure; and forming a resist pattern based on the optical image by development.
A pattern forming method comprising the steps of: A method for forming an insulating film, comprising the method according to claim 11 .