JP2024160688A - Resin composition for forming etching mask pattern, and method for producing etching mask pattern - Google Patents

Abstract

To provide a resin composition for forming an etching mask pattern, excellent in vertical alignment properties at a high film thickness, and to provide a method for producing an etching mask pattern using the same.SOLUTION: The resin composition for forming an etching mask pattern contains: a block copolymer having a first block and a second block; and a homopolymer having a number average molecular weight of less than 3,000. The first block is a polymer of a constituent unit represented by formula (b1). The second block is a random copolymer of a constituent unit represented by formula (b2m) and a constituent unit represented by formula (b2g). The volume ratio of the first block is 20-80 vol.%. The homopolymer contains a polymer of a constituent unit represented by formula (b1). R1 is an alkyl group; Rb1 is a hydrogen atom or a methyl group; n is an integer of 0-5; R2 is an alkyl group; R3 is an alkylene group; Rb2 is a hydrogen atom or the like; and x is more than 0 and less than 1.SELECTED DRAWING: None

Description

The present invention relates to a resin composition for forming an etching mask pattern and a method for producing an etching mask pattern.

In recent years, with the further miniaturization of large scale integrated circuits (LSIs), there is a demand for techniques for processing more delicate structures.
In response to such demands, techniques for forming finer patterns have been developed by utilizing a phase-separated structure formed by self-organization of a block copolymer in which mutually incompatible blocks are bonded together (see, for example, Patent Document 1).
In order to utilize the phase separation structure of a block copolymer, it is essential to form the self-organized nanostructure formed by microphase separation only in a specific region and to align it in a desired direction. To achieve this position control and orientation control, processes such as graphoepitaxy, which controls the phase separation pattern by a guide pattern, and chemical epitaxy, which controls the phase separation pattern by differences in the chemical state of the substrate, have been proposed (see, for example, Non-Patent Document 1).

Block copolymers form structures with regular periodic structures through phase separation.
The "period of the structure" means the period of the phase structure observed when the phase-separated structure is formed, and refers to the sum of the lengths of each phase that is incompatible with each other. When the phase-separated structure forms a cylindrical structure perpendicular to the substrate surface, the period (L0) of the structure is the center-to-center distance (pitch) between two adjacent cylindrical structures.

It is known that the period (L0) of the structure is determined by the degree of polymerization N and the inherent polymerization characteristics such as the Flory-Huggins interaction parameter χ. That is, the larger the product "χ·N" of χ and N, the greater the mutual repulsion between different blocks in the block copolymer. Therefore, when χ·N>10.5 (hereinafter referred to as "strength separation limit"), the repulsion between different types of blocks in the block copolymer is large, and the tendency for phase separation to occur is strong. At the strength separation limit, the period of the structure is approximately N ^2/3 ·χ ^1/6 , and the relationship of the following formula (1) is established. That is, the period of the structure is proportional to the degree of polymerization N, which correlates with the molecular weight and the molecular weight ratio between different blocks.

L0 ∝ a・N ^2/3・χ ^1/6 ...(1)
[In the formula, L0 represents the period of the structure; a represents a parameter indicating the size of the monomer; N represents the degree of polymerization; and χ represents an interaction parameter, and the larger this value, the This means that the phase separation performance is high.

Therefore, the period (L0) of the structure can be adjusted by adjusting the composition and total molecular weight of the block copolymer.
It is known that the periodic structure formed by a block copolymer changes from cylinder (columnar) to lamellar (plate-like) to sphere (spherical) depending on the volume ratio of the polymer components, etc., and the period depends on the molecular weight. Therefore, in order to form a structure with a relatively large period (L0) by utilizing the phase-separated structure formed by the self-organization of the block copolymer, a method of increasing the molecular weight of the block copolymer can be considered.

Another possible method is to use a block copolymer that has a larger interaction parameter (χ) than a general-purpose block copolymer having a styrene block and a methyl methacrylate block. For example, Patent Document 2 proposes a block copolymer in which a substituent has been introduced into a portion of the methyl methacrylate block.

JP 2008-36491 A JP 2022-020519 A

Proceedings of SPIE, Vol. 7637, No. 76370G-1 (2010).

In order to form a fine pattern using a phase separation structure formed by the self-organization of a block copolymer, it is preferable that the phase separation structure formed by the block copolymer has vertical alignment. In addition, in order to use the fine pattern as an etching mask pattern, it is preferable to vertically align the film with a relatively large thickness (for example, a thickness of 25 nm or more). However, the block copolymer described in Patent Document 1 becomes difficult to form a phase separation structure with vertical alignment when the film thickness is large.

The present invention has been made in consideration of the above circumstances, and aims to provide a resin composition for forming an etching mask pattern that has excellent vertical alignment even at high film thicknesses, and a method for producing an etching mask pattern using the same.

That is, the first aspect of the present invention is a resin composition for forming an etching mask pattern, which contains a block copolymer having a first block and a second block, and a homopolymer having a number average molecular weight of less than 3000, in which the first block is composed of a polymer having a repeating structure of a structural unit represented by the following general formula (b1), the second block is composed of a random copolymer having a structure in which a structural unit represented by the following general formula (b2m) and a structural unit represented by the following general formula (b2g) are randomly arranged, the ratio of the volume of the first block to the total volume of the first block and the second block is 20 to 80 volume %, and the homopolymer is a resin composition for forming an etching mask pattern, which contains a polymer having a repeating structure of a structural unit represented by the following general formula (b1).

［式（ｂ１）中、Ｒ^１は、アルキル基である。Ｒ^ｂ１は、水素原子又はメチル基である。ｎは０～５の整数である。ｎが２以上の整数である場合、複数のＲ^１は、それぞれ同じでもよく、異なってもよい。
式（ｂ２ｇ）中、Ｒ^２は、ケイ素原子、フッ素原子、カルボキシ基、アミノ基、シアノ基、ヒドロキシ基又はリン酸基を有してもよいアルキル基である。
Ｒ^３は、ヒドロキシ基を有してもよい、炭素原子数１～１０の直鎖状又は分岐鎖状のアルキレン基である。
式（ｂ２ｇ）及び式（ｂ２ｍ）中、Ｒ^ｂ２は、水素原子、炭素原子数１～５のアルキル基又は炭素原子数１～５のハロゲン化アルキル基である。複数のＲ^ｂ２は、同一でもよいし異なっていてもよい。
ｘは、モル比を表し、０超１未満である。］

In formula (b1), R ¹ is an alkyl group. R ^b1 is a hydrogen atom or a methyl group. n is an integer of 0 to 5. When n is an integer of 2 or more, the multiple R ^1s may be the same or different.
In formula (b2g), ^R2 is an alkyl group which may have a silicon atom, a fluorine atom, a carboxy group, an amino group, a cyano group, a hydroxy group or a phosphate group.
^R3 is a linear or branched alkylene group having 1 to 10 carbon atoms which may have a hydroxyl group.
In formulae (b2g) and (b2m), R ^b2 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Multiple R ^b2 may be the same or different.
x represents a molar ratio and is greater than 0 and less than 1.

The second aspect of the present invention is a method for producing an etching mask pattern, comprising the steps of applying the resin composition for forming an etching mask pattern described in the first aspect onto a support to form a layer containing a block copolymer, and phase-separating the layer containing the block copolymer.

According to the present invention, it is possible to provide a resin composition for forming an etching mask pattern that has excellent vertical alignment even at a high film thickness, and a method for producing an etching mask pattern using the same.

1A to 1C are schematic process diagrams illustrating an embodiment of a method for producing an etching mask pattern. FIG. 13 is a diagram illustrating an embodiment of an optional step.

In this specification and claims, the term "aliphatic" is a relative concept to aromaticity and is defined as meaning a group, compound, etc. that does not have aromaticity.
Unless otherwise specified, the term "alkyl group" includes linear, branched and cyclic monovalent saturated hydrocarbon groups. The same applies to the alkyl group in an alkoxy group.
Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The term "halogenated alkyl group" refers to an alkyl group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and examples of the halogen atoms include fluorine, chlorine, bromine and iodine atoms.
The term "fluorinated alkyl group" or "fluorinated alkylene group" refers to an alkyl group or alkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms.
The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer).
The phrase "optionally having a substituent" includes both the case where a hydrogen atom (--H) is replaced with a monovalent group and the case where a methylene group (--CH ₂ -) is replaced with a divalent group.
The term "exposure" is intended to include any concept including irradiation with radiation.
Unless otherwise specified, the "α-position (α-position carbon atom)" refers to the carbon atom to which the side chain of the block copolymer is bonded. The "α-position carbon atom" of a methyl methacrylate unit refers to the carbon atom to which the carbonyl group of methacrylic acid is bonded. The "α-position carbon atom" of a styrene unit refers to the carbon atom to which a benzene ring is bonded.
"Number average molecular weight" (Mn) is the number average molecular weight measured by size exclusion chromatography in terms of standard polystyrene unless otherwise specified. "Weight average molecular weight" (Mw) is the weight average molecular weight measured by size exclusion chromatography in terms of standard polystyrene unless otherwise specified. The value of Mn or Mw with the unit (g ^mol- ) indicates the molar mass.
In the present specification and claims, some structures represented by chemical formulas may have asymmetric carbons and may have enantiomers or diastereomers, in which case a single formula represents all of the isomers. These isomers may be used alone or as a mixture.

(Resin composition for forming etching mask pattern)
The resin composition for forming an etching mask pattern of the present embodiment contains a block copolymer having a first block and a second block, and a homopolymer having a number average molecular weight of less than 3000. The first block is composed of a polymer consisting of a repeating structure of a constitutional unit represented by the following general formula (b1). The second block is composed of a random copolymer consisting of a structure in which a constitutional unit represented by the following general formula (b2m) and a constitutional unit represented by the following general formula (b2g) are arranged in a disordered manner. The ratio of the volume of the first block to the total volume of the first block and the second block is 20 to 80 volume %. The homopolymer contains a polymer consisting of a repeating structure of a constitutional unit represented by the following general formula (b1).

［式（ｂ１）中、Ｒ^１は、アルキル基である。Ｒ^ｂ１は、水素原子又はメチル基である。ｎは０～５の整数である。ｎが２以上の整数である場合、複数のＲ^１は、それぞれ同じでもよく、異なってもよい。
式（ｂ２ｇ）中、Ｒ^２は、ケイ素原子、フッ素原子、カルボキシ基、アミノ基、シアノ基、ヒドロキシ基又はリン酸基を有してもよいアルキル基である。
Ｒ^３は、ヒドロキシ基を有してもよい、炭素原子数１～１０の直鎖状又は分岐鎖状のアルキレン基である。
式（ｂ２ｇ）及び式（ｂ２ｍ）中、Ｒ^ｂ２は、水素原子、炭素原子数１～５のアルキル基又は炭素原子数１～５のハロゲン化アルキル基である。複数のＲ^ｂ２は、同一でもよいし異なっていてもよい。
ｘは、モル比を表し、０超１未満である。］

In formula (b1), R ¹ is an alkyl group. R ^b1 is a hydrogen atom or a methyl group. n is an integer of 0 to 5. When n is an integer of 2 or more, the multiple R ^1s may be the same or different.
In formula (b2g), ^R2 is an alkyl group which may have a silicon atom, a fluorine atom, a carboxy group, an amino group, a cyano group, a hydroxy group or a phosphate group.
^R3 is a linear or branched alkylene group having 1 to 10 carbon atoms which may have a hydroxyl group.
In formulae (b2g) and (b2m), R ^b2 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Multiple R ^b2 may be the same or different.
x represents a molar ratio and is greater than 0 and less than 1.

<Block copolymer (BCP) component>
A block copolymer is a polymer in which multiple types of blocks (partial constituent components in which the same type of constituent units are repeatedly bonded) are bonded together. The number of types of blocks constituting a block copolymer may be two or more.
The block copolymer (hereinafter also referred to as "(BCP) component") in this embodiment has a first block and a second block.

<First Block>
The first block is composed of a polymer having a repeating structure of a structural unit represented by the following general formula (b1) (hereinafter, also referred to as structural unit (b1)).

［式中、Ｒ^１は、アルキル基である。Ｒ^ｂ１は、水素原子又はメチル基である。ｎは０～５の整数である。ｎが２以上の整数である場合、複数のＲ^１は、それぞれ同じでもよく、異なってもよい。］

[In the formula, R ¹ is an alkyl group. R ^b1 is a hydrogen atom or a methyl group. n is an integer of 0 to 5. When n is an integer of 2 or more, the multiple R ^1s may be the same or different.]

In the formula (b1), R ¹ is an alkyl group. The alkyl group preferably has 1 to 5 carbon atoms, more preferably has 1 to 4 carbon atoms, and even more preferably has 1 to 3 carbon atoms, and is further preferably an ethyl group or a methyl group. ^{R 1} is particularly preferably a methyl group.

In the formula (b1), R ^b1 is a hydrogen atom or a methyl group.
In the formula (b1), n is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and even more preferably 0 or 1.

<Second Block>
The second block is composed of a random copolymer having a structure in which a structural unit represented by the following general formula (b2m) (hereinafter also referred to as structural unit (b2m)) and a structural unit represented by the following general formula (b2g) (hereinafter also referred to as structural unit (b2g)) are arranged in a disordered manner.

［式（ｂ２ｇ）中、Ｒ^２は、ケイ素原子、フッ素原子、カルボキシ基、アミノ基、シアノ基、ヒドロキシ基又はリン酸基を有してもよいアルキル基である。
Ｒ^３は、ヒドロキシ基を有してもよい、炭素原子数１～１０の直鎖状又は分岐鎖状のアルキレン基である。
式（ｂ２ｇ）及び式（ｂ２ｍ）中、Ｒ^ｂ２は、水素原子、炭素原子数１～５のアルキル基又は炭素原子数１～５のハロゲン化アルキル基である。複数のＲ^ｂ２は、同一でもよいし異なっていてもよい。
ｘは、モル比を表し、０超１未満である。］

In formula (b2g), R ² represents an alkyl group which may have a silicon atom, a fluorine atom, a carboxy group, an amino group, a cyano group, a hydroxy group or a phosphate group.
^R3 is a linear or branched alkylene group having 1 to 10 carbon atoms which may have a hydroxyl group.
In formulae (b2g) and (b2m), R ^b2 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Multiple R ^b2 may be the same or different.
x represents a molar ratio and is greater than 0 and less than 1.

(Structural unit (b2m))
The structural unit (b2m) is a structural unit represented by general formula (b2m) above.
In the formula (b2m), R ^b2 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. The alkyl group having 1 to 5 carbon atoms of R ^b2 is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. As the halogen atom, a fluorine atom is particularly preferable.
R ^b2 is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is more preferable, and a methyl group is even more preferable.

(Structural unit (b2g))
The structural unit (b2g) is a structural unit represented by the above general formula (b2g).

In the formula (b2g), R ^b2 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. R ^b2 is the same as R ^b2 in the formula (b2m).

In the formula (b2g), R ² is an alkyl group which may have a silicon atom, a fluorine atom, a carboxy group, an amino group, a cyano group, a hydroxy group, or a phosphate group. The alkyl group may be linear, branched, or may include a ring structure. The alkyl group is preferably a linear, branched, or cyclic alkyl group, and more preferably a linear or cyclic alkyl group. When the alkyl group is linear, the number of carbon atoms may be 1 or more, and preferably 2 or more. The upper limit of the number of carbon atoms of the linear alkyl group is not particularly limited, but from the viewpoint of phase separation performance, the number of carbon atoms is preferably 15 or less, more preferably 10 or less, even more preferably 8 or less, and even more preferably 6 or less. When the alkyl group is branched, the number of carbon atoms may be 3 or more. The upper limit of the number of carbon atoms of the branched alkyl group is not particularly limited, but from the viewpoint of phase separation performance, the number of carbon atoms is preferably 15 or less, more preferably 10 or less, even more preferably 8 or less, and even more preferably 6 or less.
When the alkyl group includes a ring structure, R ² may be a cycloalkyl group, a linear or branched alkyl group with a cycloalkylene group interposed therein, or a linear or branched alkyl group with a cycloalkyl group bonded to the end thereof. The cycloalkyl group and the cycloalkylene group may be a monocyclic group or a polycyclic group, but a monocyclic group is preferred. When the cycloalkyl group or the cycloalkylene group is a monocyclic group, a 3- to 8-membered ring is preferred, a 3- to 6-membered ring is more preferred, and a 5- to 6-membered ring is even more preferred. When the alkyl group includes a ring structure, R ² may have 3 or more carbon atoms. The upper limit of the number of carbon atoms of the alkyl group including the ring structure is not particularly limited, but from the viewpoint of phase separation performance, the number of carbon atoms is preferably 15 or less, more preferably 10 or less, even more preferably 8 or less, and even more preferably 6 or less.
The alkyl group for ^R2 preferably has 2 to 15 carbon atoms, more preferably has 2 to 10 carbon atoms, even more preferably has 2 to 8 carbon atoms, and even more preferably has 2 to 6 carbon atoms.
The alkyl group of ^R2 is preferably a linear alkyl group or a cycloalkyl group having 2 to 6 carbon atoms.

The alkyl group of ^R2 may have a silicon atom, a fluorine atom, a carboxy group, an amino group, a cyano group, a hydroxy group, or a phosphate group. When the alkyl group of ^R2 has a fluorine atom, a carboxy group, an amino group, a cyano group, a hydroxy group, or a phosphate group, the fluorine atom, the carboxy group, the amino group, the cyano group, the hydroxy group, or the phosphate group may be a substituent substituting a hydrogen atom of the alkyl group. The number of hydrogen atoms substituted by the group is not particularly limited, but is preferably 1 to 3.
When the alkyl group of ^R2 has a silicon atom, the silicon atom may be a substituent that replaces a methylene group ( _-CH2- ) in the alkyl group. The number of methylene groups substituted with silicon atoms is not particularly limited, but one is preferred.
^R2 is preferably an alkyl group which may be substituted with an alkylsilyl group, a fluoromethyl group, a carboxy group, an amino group, a hydroxy group, a cyano group, or a phosphate group. The alkyl group in the alkylsilyl group preferably has 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms. The alkylsilyl group is preferably a trialkylsilyl group, more preferably a triethylsilyl group or a trimethylsilyl group, and even more preferably a trimethylsilyl group. The fluoromethyl group is preferably a trifluoromethyl group.

Preferred examples of ^R2 are shown below, but are not limited to these. In the following formula, * represents a bond bonded to the sulfur atom (S) in the above formula (b2g).

［式中、Ｙ^２は、単結合又は炭素原子数１～１５の直鎖状又は分岐鎖状のアルキレン基である。ｐは、１～１０の整数である。］

[In the formula, ^Y2 is a single bond or a linear or branched alkylene group having 1 to 15 carbon atoms, and p is an integer from 1 to 10.]

In the formulae (r2-1) to (r2-7), ^Y2 is a single bond or a linear or branched alkylene group having 1 to 15 carbon atoms. When the alkylene group is linear, it more preferably has 1 to 10 carbon atoms, even more preferably has 1 to 8 carbon atoms, and particularly preferably has 1 to 5 carbon atoms. When the alkylene group is branched, it more preferably has 2 to 10 carbon atoms, even more preferably has 2 to 8 carbon atoms, and particularly preferably has 2 to 6 carbon atoms.
The alkylene group of ^Y2 is preferably a linear alkylene group having 1 to 5 carbon atoms or a branched alkylene group having 2 to 6 carbon atoms.
When R ² is a group represented by any one of the formulae (r2-1) to (r2-8), Y ² is preferably a linear or branched alkylene group having 1 to 15 carbon atoms, more preferably a linear alkylene group having 1 to 5 carbon atoms or a branched alkylene group having 2 to 6 carbon atoms. When R ² is a group represented by the formula (r2-9), Y ² is preferably a single bond or a linear alkylene group having 1 to 5 carbon atoms, more preferably a single bond.
In formula (r2-9), p is preferably an integer of 1 to 6, more preferably an integer of 1 to 4, and even more preferably 3 or 4.

Specific examples of ^R2 are shown below, but are not limited to these. In the following formula, * represents a bond bonded to the sulfur atom (S) in the above formula (b2g).

［式中、ｑは、１～１５の整数である。ｑ’は、０～１５の整数である。ｐは、１～１０の整数である。ｐ’は、それぞれ独立に、０～１０の整数である。］

[In the formula, q is an integer of 1 to 15. q' is an integer of 0 to 15. p is an integer of 1 to 10. Each p' is independently an integer of 0 to 10.]

In the above formula, q is preferably an integer of 1 to 10, more preferably an integer of 1 to 8, even more preferably an integer of 1 to 6, and particularly preferably an integer of 1 to 5.
In the formulae (r2-18) and (r2-19), q′ is preferably an integer of 0 to 10, more preferably an integer of 0 to 8, even more preferably an integer of 0 to 6, and particularly preferably an integer of 0 to 5.
In the above formula (r2-18), p is preferably an integer of 1 to 6, more preferably an integer of 1 to 4, and even more preferably 3 or 4.
In the above formula (r2-19), p' is preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 3, and particularly preferably 1 or 2.

In the formula (b2g), R ³ is a linear or branched alkylene group having 1 to 10 carbon atoms, which may have a hydroxyl group. When the alkylene group is linear, the number of carbon atoms may be 1 or more, but preferably 3 or more. The upper limit of the number of carbon atoms of the linear alkylene group is preferably 8 or less, more preferably 5 or less, and even more preferably 4 or less, from the viewpoint of phase separation performance. The number of carbon atoms of the linear alkylene group is particularly preferably 3. When the alkylene group is branched, the number of carbon atoms may be 3 or more, but preferably 4 or more. The upper limit of the number of carbon atoms of the branched alkylene group is preferably 8 or less, and more preferably 5 or less, from the viewpoint of phase separation performance. The number of carbon atoms of the alkylene group is preferably 3 to 10, more preferably 3 to 8, even more preferably 3 to 5, even more preferably 3 to 4, and especially preferably 3.
The alkylene group of ^R3 is preferably a linear alkylene group having 3 carbon atoms.

The alkylene group of ^R3 may have a hydroxy group. The hydroxy group may be a substituent that replaces a hydrogen atom of the alkylene group. The number of hydrogen atoms replaced by the hydroxy group is not particularly limited, but is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

The structural unit (b2g) is preferably a structural unit represented by the following general formula (b2g-1):

［式中、Ｒ^４は、水素原子又はヒドロキシ基である。ｋ１及びｋ２は、それぞれ独立に、１～５の整数である。Ｒ^ｂ２及びＲ^２は、前記式（ｂ２ｇ）におけるＲ^ｂ２及びＲ^２と同様である。］

[In the formula, R ⁴ is a hydrogen atom or a hydroxy group. k1 and k2 each independently represent an integer of 1 to 5. R ^b2 and R ² are the same as R ^b2 and R ² in the formula (b2g).]

In the formula (b2g-1), R ^b2 and R ² are the same as R ^b2 and R ² in the formula (b2g). R ² is preferably one represented by the formulas (r2-1) to (r2-9), and more preferably one represented by the formulas (r2-10) to (r2-19).

In the above formula (b2g-1), R ⁴ is a hydrogen atom or a hydroxy group.

In the formula (b2g-1), k1 and k2 are each independently an integer from 1 to 5. k1 and k2 are preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

Specific examples of the structural unit (b2g) are shown below, but are not limited to these. In the following formula, R represents a methyl group or a hydrogen atom, with a methyl group being preferred.

The second block is composed of a random copolymer having a structure in which the structural units (b2g) and (b2m) are arranged in a disordered manner. In the formulas (b2g) and (b2m), x and 1-x represent the molar ratios of the structural units (b2g) and (b2m). x is greater than 0 and less than 1. x can be appropriately determined depending on the type of phase separation structure desired. When a phase separation structure having a lamellar structure is formed, x is preferably 0.01 to 0.3, and more preferably 0.1 to 0.3. When a phase separation structure having a cylindrical structure is formed, x is preferably 0.01 to 0.1, and more preferably 0.01 or more and less than 0.1.

In the (BCP) component, the volume ratio of the first block to the total volume of the first block and the second block is 20 to 80 volume %. The volume ratio of the first block can be appropriately determined depending on the type of phase separation structure desired. When forming a phase separation structure with a lamellar structure, the volume ratio of the first block is preferably 35 to 65 volume %. When forming a phase separation structure with a cylindrical structure, the volume ratio of the first block is preferably 20 to 35 volume % or 65 to 80 volume %.

The ratio of the volume of the first block to the total volume of the first block and the second block in the (BCP) component can be calculated as follows.
From the analysis results of ¹ H NMR, the mol% of the first block and the second block in the (BCP) component are calculated, and further, the mass% of each block is calculated from the molecular weight of each block. The mass% of each block is divided by the density of each block to calculate the volume ratio of each block, and the volume% of the first block in the (BCP) component is calculated from the volume ratio. The density of each block can be estimated by the atomic group contribution method (Fedors, RF Polym. Eng. Sci. 1974, 14,147-154.). When the first block is a polystyrene block (PS), the density of PS can be 1.05 gm ⁻³ . When the second block is a polystyrene block (PS), the density of PS can be 1.05 gm ⁻³ . When the second block has a structural unit derived from methyl methacrylate, the density of the structure composed of the structural units can be 1.18 gcm ^-3 . When the second block has a structural unit derived from 2-hydroxy-3-(2,2,2-trifluoroethylsulfanyl)propyl methacrylate, the density of the structure composed of the structural units can be 1.43 gcm ^- 3. The density of each block can be that described in the literature (Polymer Handbook, 4th ed.; Wiley: New York, 2004.) or the like.

The (BCP) component may have other blocks in addition to the first block and the second block. In a preferred embodiment, the (BCP) component is a block copolymer composed of a first block and a second block.

The number average molecular weight (Mn) (based on polystyrene equivalent by size exclusion chromatography) of the (BCP) component is not particularly limited, but is preferably 5,000 to 100,000, more preferably 6,000 to 7,000, even more preferably 8,000 to 40,000, and particularly preferably 10,000 to 40,000.
The molecular weight dispersity (Mw/Mn) of each block constituting the (BCP) component is preferably from 1.0 to 1.5, more preferably from 1.0 to 1.4, and even more preferably from 1.0 to 1.3.

<<Production method of block copolymer ((BCP) component)>>
The (BCP) component can be produced, for example, by a production method having the steps shown below.
Step (p1): A step of obtaining a block copolymer having a first block and a precursor of a second block (hereinafter, also referred to as a "BCP precursor").
Step (p2): A step of reacting a precursor of the second block in the BCP precursor with a compound represented by R ² -SH (R ² is the same as R ² in the above formula (b2g)) to obtain a block copolymer containing a first block and a second block ((BCP) component).

Step (p1):
The precursor of the second block is a random copolymer having a structure in which the structural unit (b2gp), which is a precursor of the structural unit (b2g), and the structural unit (b2m) are arranged in a disordered manner. The structural unit (b2gp) is a structural unit containing an epoxy group or a vinyl group, and examples of the structural unit represented by the following general formula (b2gp) are:

［式中、Ｒｐ^２は、エポキシ基又はビニル基を表す。Ｙｐ^２は、炭素原子数１～８の直鎖状又は分岐鎖状のアルキレン基を表す。Ｒ^ｂ２は、水素原子、炭素原子数１～５のアルキル基又は炭素原子数１～５のハロゲン化アルキル基である。］

[In the formula, ^Rp2 represents an epoxy group or a vinyl group. ^Yp2 represents a linear or branched alkylene group having 1 to 8 carbon atoms. ^Rb2 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.]

The BCP precursor can be obtained, for example, by carrying out a polymerization reaction of a monomer (e.g., styrene or a derivative thereof, hereinafter also referred to as monomer (b1)) that induces the structural unit (b1), and then adding a monomer (e.g., glycidyl methacrylate, allyl methacrylate, etc., hereinafter also referred to as monomer (b2gp)) that induces the structural unit (b2m) to the polymerization reaction liquid and further carrying out a polymerization reaction. Alternatively, the BCP precursor can be obtained by carrying out a polymerization reaction using a mixture of monomer (b2gp) and monomer (b2m), and then adding monomer (b1) to the polymerization reaction liquid and further carrying out a polymerization reaction. Living polymerization is preferred for the polymerization reaction because it is narrowly dispersed and easy to synthesize. Preferred living polymerization methods include living anionic polymerization and living radical polymerization, and living anionic polymerization is particularly preferred because it can achieve a more narrow dispersion.

Step (p2):
The compound represented by R ² -SH (hereinafter also referred to as "compound (R ² -SH)") is a compound that reacts with the epoxy group or vinyl group of the structural unit (b2gp) to convert the structural unit (b2gp) to the structural unit (b2g).
When the structural unit (b2gp) contains an epoxy group, the reaction of the BCP precursor with the compound (R ² -SH) can be carried out in an organic solvent such as tetrahydrofuran in the presence of a catalyst such as lithium hydroxide. The reaction temperature can be, for example, 20 to 60°C, preferably 30 to 50°C, and more preferably 35 to 45°C. The reaction time can be set appropriately depending on the amount of the BCP precursor used, and can be a time sufficient for all of the structural units (b2gp) in the precursor of the second block to be converted to the structural units (b2g). The reaction time can be, for example, 1 to 10 hours. When the structural unit (b2gp) contains a vinyl group, the reaction of the BCP precursor with the compound (R ² -SH) can be carried out by a thiol-ene reaction. The thiol-ene reaction can be carried out in an organic solvent such as tetrahydrofuran in the presence of a catalyst such as azobisisobutyronitrile (AIBN). The reaction temperature is, for example, 60 to 90° C., preferably 70 to 90° C., and more preferably 75 to 85° C. The reaction time can be appropriately set depending on the amount of BCP precursor used, and may be any time sufficient for all of the structural units (b2gp) in the precursor of the second block to be converted to structural units (b2g). The reaction time may be, for example, 1 to 10 hours.

［式中、Ｒ^１、Ｒ^ｂ１、及びｎは、前記式（ｂ１）中のＲ^１、Ｒ^ｂ１及びｎとそれぞれ同じである。Ｒ^２及びＲ^３は、前記式（ｂ２ｇ）中のＲ^２及びＲ^３と同じである。Ｒ^ｂ２及びｘは、前記式（ｂ２ｇ）及び式（ｂ２ｍ）中のＲ^ｂ２及びｘと同じである。Ｙｐ²は、炭素原子数１～８の直鎖状又は分岐鎖状のアルキル基を表す。Ｒｐ^２は、エポキシ基又はビニル基を表す。］

[In the formula, R ¹ , R ^b1 , and n are the same as R ¹ , R ^{b1 ,} and n in the formula (b1), respectively. ^{R 2} and R ³ are the same as R ² and R ³ in the formula (b2g). R ^b2 and x are the same as R ^b2 and x in the formulas (b2g) and (b2m). Yp ² represents a linear or branched alkyl group having 1 to 8 carbon atoms. Rp ² represents an epoxy group or a vinyl group.]

<Homopolymer: Component (H)>
The homopolymer is a homopolymer (hereinafter also referred to as "component (H)") having a number average molecular weight of less than 3000. The component (H) contains a polymer composed of a repeating structure of the structural unit (b1) represented by the general formula (b1) above.

(Polymer having repeating structures of structural unit (b1): component (H1))
The component (H) contains a polymer (hereinafter also referred to as "component (H1)") that is composed of a repeating structure of the structural unit (b1). The explanation of the structural unit (b1) contained in the component (H1) is the same as the explanation of the structural unit (b1) contained in the first block of the component (BCP) above.
The structural unit (b1) in the component (H1) may be the same as or different from the structural unit (b1) in the first block of the component (BCP), but is preferably the same. For example, when the first block of the component (BCP) is a polystyrene block, the component (H1) is preferably polystyrene.

The number average molecular weight (Mn) of the (H1) component (based on polystyrene conversion by size exclusion chromatography) may be less than 3,000. When the (H1) component has an Mn of less than 3,000, the (H1) component is easily uniformly dispersed in the layer containing the block copolymer, and the vertical alignment property is improved at a high film thickness (for example, a film thickness of 25 nm or more). The upper limit of the Mn of the (H1) component is, for example, 2,900 or less, 2,800 or less, 2,700 or less, 2,600 or less, 2,500 or less, 2,400 or less, 2,300 or less, 2,200 or less, 2,100 or less, or 2,000 or less. The lower limit of the Mn of the (H1) component is, for example, 1,000 or more, or 1,200 or more. The Mn of the component (H1) is, for example, in the range of 1,000 to 2,900, preferably 1,000 to 2,500, and more preferably 1,200 to 2,000.
When the Mn of the component (H1) is within the above preferred range, a phase-separated structure with excellent vertical alignment properties is easily formed.

The content of the (H1) component in the resin composition for forming an etching mask pattern of this embodiment is 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, relative to 100 parts by mass of the (BCP) component. The upper limit of the content of the (H1) component is 100 parts by mass or less, preferably 70 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the (BCP) component. The content of the (H1) component is in the range of 1 to 100 parts by mass, preferably 10 to 70 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 15 to 30 parts by mass, relative to 100 parts by mass of the (BCP) component.
When the content of the component (H1) is within the above preferred range, a phase-separated structure having excellent vertical alignment properties is easily formed.

The component (H1) may be used alone or in combination of two or more types.
When the component (H) contains two or more types of the component (H1), the content of the component (H1) means the total content of the two or more types of the component (H1).

(Other homopolymers)
The component (H) may contain, in addition to the component (H1), another homopolymer. Examples of the other homopolymer include a polymer having a repeating structure of the structural unit (b2m) represented by the general formula (b2m) (hereinafter, also referred to as "component (H2)").

<<Polymer Having Repeating Structure of Structural Unit (b2m): Component (H2)>>
The explanation for the structural unit (b2m) contained in the (H2) component is the same as the explanation for the structural unit (b2m) contained in the second block of the (BCP) component described above.
The structural unit (b2m) in the (H2) component may be the same as or different from the structural unit (b2m) in the second block of the (BCP) component, but is preferably the same. For example, when the second block of the (BCP) component is a polymethyl methacrylate block, the (H1) component is preferably polymethyl methacrylate.

The number average molecular weight (Mn) of the (H2) component (based on polystyrene conversion by size exclusion chromatography) may be less than 3,000. When the (H2) component has an Mn of less than 3,000, the (H2) component is easily dispersed uniformly in the layer containing the block copolymer, and the vertical alignment property is improved at a high film thickness (for example, a film thickness of 25 nm or more). The upper limit of the Mn of the (H2) component is, for example, 2,900 or less, 2,800 or less, 2,700 or less, 2,600 or less, 2,500 or less, 2,400 or less, 2,300 or less, 2,200 or less, 2,100 or less, or 2,000 or less. The lower limit of the Mn of the (H2) component is, for example, 1,000 or more, or 1,200 or more. The Mn of the component (H2) is, for example, in the range of 1,000 to 2,900, preferably 1,000 to 2,500, and more preferably 1,200 to 2,000.
When the Mn of the component (H2) is within the above-mentioned preferred range, a phase-separated structure with excellent vertical alignment properties is easily formed.

When the (H) component includes the (H2) component, the content of (H2) in the composition for forming an etching mask pattern of this embodiment may be 90 parts by mass or less, preferably 70 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the (BCP) component. When the (H) component includes the (H2) component, the content of the (H2) component may be 1 part by mass or more, 5 parts by mass or more, 10 parts by mass or more, or 15 parts by mass or more, relative to 100 parts by mass of the (BCP) component. The content of the (H2) component may be in the range of 0 to 90 parts by mass, preferably 0 to 70 parts by mass, more preferably 0 to 50 parts by mass, even more preferably 0 to 30 parts by mass, and even more preferably 0 to 25 parts by mass, relative to 100 parts by mass of the (BCP) component.
When the content of the component (H2) is within the above preferred range, a phase-separated structure having excellent vertical alignment properties is easily formed.

The component (H2) may be used alone or in combination of two or more types.
When the component (H) contains two or more types of the component (H2), the content of the component (H2) means the total content of the two or more types of the component (H2).

When the (H) component contains the (H2) component, the content of the (H2) component is preferably 100 parts by mass or less per 100 parts by mass of the (H1) component. The content of the (H2) component may be 90 parts by mass or less, 80 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, or 40 parts by mass or less per 100 parts by mass of the (H1) component.

The content of the (H) component in the resin composition for forming an etching mask pattern of this embodiment is preferably 100 parts by mass or less relative to 100 parts by mass of the (BCP) component. When the (H) component contains two or more homopolymers, the content of the (H) component means the total content of the two or more homopolymers. The content of the (H) component is 5 parts by mass or more relative to 100 parts by mass of the (BCP) component, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 30 parts by mass or more. The upper limit of the content of the (H) component is 100 parts by mass or less relative to 100 parts by mass of the (BCP) component, preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. The content of the component (H) is in the range of 5 to 100 parts by mass, preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass, per 100 parts by mass of the component (BCP).
When the content of the component (H) is within the above preferred range, a phase-separated structure having excellent vertical alignment properties is easily formed.

The resin composition for forming an etching mask pattern of this embodiment may or may not contain a homopolymer having an Mn of 3,000 or more, but it is preferable that it does not contain one. By not containing a homopolymer having an Mn of 3,000 or more, the resin composition for forming an etching mask pattern of this embodiment is more likely to form a phase separation structure with excellent vertical alignment.

<Organic Solvent Component>
The resin composition for forming an etching mask pattern of the present embodiment can be prepared by dissolving the above-mentioned components (BCP) and (H) in an organic solvent component.
The organic solvent component may be any solvent capable of dissolving each component used to form a homogeneous solution, and any solvent known in the art as a solvent for film compositions mainly composed of resins may be used.

Examples of the organic solvent component include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate; ether bonds such as monoalkyl ethers, monomethyl ether, monoethyl ether, monopropyl ether, and monobutyl ether of the polyhydric alcohols or the compounds having an ester bond, and monophenyl ether. derivatives of polyhydric alcohols such as compounds having a bond [among which, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; cyclic ethers such as dioxane, esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; and aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene.
The organic solvent component may be used alone or in a mixture of two or more kinds. Among them, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone, and EL are preferred.

A mixed solvent obtained by mixing PGMEA and a polar solvent is also preferred. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, and is preferably within a range of 1:9 to 9:1, and more preferably 2:8 to 8:2.
For example, when EL is blended as the polar solvent, the mass ratio of PGMEA:EL is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. When PGME is blended as the polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, more preferably 2:8 to 8:2, and even more preferably 3:7 to 7:3. When PGME and cyclohexanone are blended as the polar solvent, the mass ratio of PGMEA:(PGME+cyclohexanone) is preferably 1:9 to 9:1, more preferably 2:8 to 8:2, and even more preferably 3:7 to 7:3.

As the organic solvent component in the resin composition for forming an etching mask pattern, a mixed solvent of PGMEA or EL, or a mixed solvent of PGMEA and a polar solvent, and γ-butyrolactone is also preferred. In this case, the mass ratio of the former to the latter is preferably 70:30 to 95:5.
The organic solvent component contained in the resin composition for forming an etching mask pattern is not particularly limited, and is appropriately set at a coatable concentration according to the coating film thickness, and is generally used so that the solid content concentration is within the range of 0.2 to 70 mass %, preferably 0.2 to 50 mass %.

<Optional ingredients>
In addition to the above-mentioned component (BCP), component (H) and organic solvent component, the resin composition for forming an etching mask pattern may further contain, as desired, compatible additives such as an additional resin for improving the performance of the layer, a surfactant for improving coatability, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, a sensitizer, a base amplifier, a basic compound, etc.

According to the resin composition for forming an etching mask pattern of this embodiment described above, by containing the (H) component in addition to the (BCP) component, a phase separation structure with good vertical alignment can be formed even at a high film thickness (for example, a film thickness of 25 nm or more). Therefore, a vertically aligned phase separation structure can be formed at a high film thickness (for example, a film thickness of 25 nm or more, preferably 30 nm or more), and the phase separation structure can be used as an etching mask pattern.

The (BCP) component can increase the value of χ compared to a block copolymer (PS-b-PMMA) having a styrene block and a methyl methacrylate block, because the second block has the structural unit (b2g). This allows a fine phase-separated structure with a shorter period to be formed using a block copolymer with a lower degree of polymerization (N). However, when the value of χ is high, the vertical alignment tends to decrease. In particular, at a film thickness applicable to an etching mask pattern (for example, a film thickness of 25 nm or more, preferably 30 nm or more), the (BCP) component is less likely to form a vertically aligned phase-separated structure.
The resin composition for forming an etching mask pattern of the present embodiment contains the component (H) in addition to the component (BCP), thereby improving the vertical alignment property and enabling the formation of a vertically oriented phase-separated structure with a film thickness applicable to an etching mask pattern.

(Method of Manufacturing Etching Mask Pattern)
The method for producing an etching mask pattern of the present embodiment includes a step of applying the resin composition for forming an etching mask pattern of the above-described embodiment onto a support to form a layer containing a block copolymer (hereinafter referred to as "step (i)"), and a step of phase-separating the layer containing the block copolymer (hereinafter referred to as "step (ii)").
Hereinafter, such a method for producing an etching mask pattern will be specifically described with reference to Fig. 1. However, the present invention is not limited to this.

FIG. 1 shows an embodiment of a method for producing an etching mask pattern.
In the embodiment shown in FIG. 1, first, a base agent is applied onto a support 1 to form a base agent layer 2 (FIG. 1(I)).
Next, the resin composition for forming an etching mask pattern of the above-mentioned embodiment is applied onto the undercoat agent layer 2 to form a layer containing a block copolymer (BCP layer) 3 (FIG. 1(II); this is step (i)).
Next, an annealing treatment is performed by heating, so that the BCP layer 3 is separated into a phase 3a and a phase 3b (FIG. 1(III); step (ii)).
As a result, a structure 3' including a phase-separated structure is produced on the support 1 on which the undercoat agent layer 2 is formed. The structure 3' including a phase-separated structure can be used to produce an etching mask pattern.

[Step (i)]
In the step (i), a resin composition for forming an etching mask pattern is applied onto a support 1 to form a BCP layer 3 .
In the embodiment shown in FIG. 1, first, a base agent is applied onto a support 1 to form a base agent layer 2 .
By providing the undercoat agent layer 2 on the support 1, a balance of hydrophilicity and hydrophobicity between the surface of the support 1 and the layer containing a block copolymer (BCP layer) 3 can be achieved.
That is, when the primer layer 2 contains a resin component having the structural unit (b1) constituting the first block, the adhesion between the phase of the BCP layer 3 consisting of the first block and the support 1 is enhanced. When the primer layer 2 contains a resin component having the structural unit (b2) constituting the second block, the adhesion between the phase of the BCP layer 3 consisting of the second block and the support 1 is enhanced.
Accordingly, due to phase separation of the BCP layer 3, a phase-separated structure oriented in a direction perpendicular to the surface of the support 1 is easily formed.

Base:
As the undercoat agent, a resin composition can be used.
The resin composition for the undercoat agent can be appropriately selected from among conventionally known resin compositions used for thin film formation, depending on the type of block constituting the (BCP) component.
The resin composition for the undercoat agent may be, for example, a thermally polymerizable resin composition, or may be a photosensitive resin composition such as a positive resist composition or a negative resist composition. In addition, a compound may be used as a surface treatment agent, and a non-polymerizable film formed by applying the compound may be used as the undercoat agent layer. For example, a siloxane-based organic monomolecular film formed using phenethyltrichlorosilane, octadecyltrichlorosilane, hexamethyldisilazane, or the like as a surface treatment agent may also be suitably used as the undercoat agent layer.

Examples of such resin compositions include a resin composition containing a resin having both the structural unit (b1) constituting the first block and the structural unit (b2m) constituting the second block, and a resin composition containing a resin having both structural units having high affinity with each of the blocks constituting the (BCP) component.
As the resin composition for the primer, it is preferable to use, for example, a composition containing a resin having both styrene and methyl methacrylate as constituent units, or a compound or composition containing both a moiety having high affinity for styrene, such as an aromatic ring, and a moiety having high affinity for methyl methacrylate (such as a highly polar functional group).
Examples of resins having both styrene and methyl methacrylate as structural units include random copolymers of styrene and methyl methacrylate, alternating polymers of styrene and methyl methacrylate (monomers copolymerized alternately), random copolymers of styrene, methyl methacrylate, and (hydroxyethyl) methacrylate, etc. From the viewpoint of forming a vertically oriented phase separation structure in the BCP layer, the proportion of the styrene structural unit in the resin is preferably 20 to 90 mol%, more preferably 30 to 85 mol%, relative to the total (100 mol%) of all structural units constituting the resin.
In addition, as a composition containing both a site having high affinity with styrene and a site having high affinity with methyl methacrylate, for example, a composition containing a resin obtained by polymerizing at least a monomer having an aromatic ring and a monomer having a highly polar functional group as a monomer. Examples of monomers having an aromatic ring include monomers having aryl groups in which one hydrogen atom is removed from an aromatic hydrocarbon ring, such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group, or monomers having heteroaryl groups in which a part of the carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. In addition, examples of monomers having a highly polar functional group include monomers having a trimethoxysilyl group, a trichlorosilyl group, an epoxy group, a glycidyl group, a carboxy group, a hydroxyl group, a cyano group, or a hydroxyalkyl group in which a part of the hydrogen atoms of an alkyl group is substituted with a hydroxyl group. From the viewpoint of forming a vertically oriented phase separation structure in the BCP layer, the proportion of structural units derived from a monomer having an aromatic ring in the resin is preferably 20 to 90 mol %, and more preferably 30 to 85 mol %, relative to the total (100 mol %) of all structural units constituting the resin.
Other examples of compounds that contain both a moiety with high affinity for styrene and a moiety with high affinity for methyl methacrylate include compounds that contain both an aryl group and a highly polar functional group, such as phenethyltrichlorosilane, and compounds that contain both an alkyl group and a highly polar functional group, such as alkylsilane compounds.

The resin composition for the base can be produced by dissolving the above-mentioned resin in a solvent.
Such a solvent may be any solvent capable of dissolving each component used to form a homogeneous solution, and examples thereof include the same organic solvent components as those exemplified in the description of the resin composition for forming an etching mask pattern of the above embodiment.

The type of the support 1 is not particularly limited as long as the resin composition can be applied to the surface thereof. For example, a substrate made of an inorganic material such as metal (silicon, copper, chromium, iron, aluminum, etc.), glass, titanium oxide, silica, mica, etc.; a substrate made of an oxide such as _SiO2 ; a substrate made of a nitride such as SiN; a substrate made of an oxynitride such as SiON; a substrate made of an organic material such as acrylic, polystyrene, cellulose, cellulose acetate, phenolic resin, etc. can be mentioned. Among these, a metal substrate is preferable, and a cylinder structure is easily formed on, for example, a silicon substrate (Si substrate) or a copper substrate (Cu substrate). Among these, a Si substrate is particularly preferable.
The size and shape of the support 1 are not particularly limited. The support 1 does not necessarily have to have a smooth surface, and substrates of various shapes can be appropriately selected. For example, substrates having a curved surface, flat plates with an uneven surface, and substrates having a flaky shape can be mentioned.

The surface of the support 1 may be provided with an inorganic and/or organic film.
The inorganic film may be an inorganic anti-reflective coating (inorganic BARC), and the organic film may be an organic anti-reflective coating (organic BARC).
The inorganic film can be formed, for example, by applying an inorganic anti-reflective coating composition, such as a silicon-based material, onto a support and baking the composition.
The organic film can be formed, for example, by applying an organic film-forming material, which is a solution of the resin components constituting the film in an organic solvent, onto a substrate using a spinner or the like, and baking the material under heating conditions of preferably 200 to 300° C., preferably 30 to 300 seconds, more preferably 60 to 180 seconds. This organic film-forming material does not necessarily need to be sensitive to light or electron beams, unlike a resist film, and may or may not be sensitive. Specifically, resists and resins commonly used in the manufacture of semiconductor elements and liquid crystal display elements can be used.
In addition, the material for forming the organic film is preferably a material capable of forming an organic film that can be etched, particularly dry etched, so that an organic film pattern can be formed by etching an organic film using a pattern made of a block copolymer formed by processing the BCP layer 3. Among them, it is preferable that the material is a material capable of forming an organic film that can be etched by oxygen plasma etching or the like. Such a material for forming the organic film may be a material that has been used to form an organic film such as an organic BARC. For example, the ARC series manufactured by Nissan Chemical Industries, Ltd., the AR series manufactured by Rohm and Haas, and the SWK series manufactured by Tokyo Ohka Kogyo Co., Ltd. can be mentioned.

The method for applying the primer onto the support 1 to form the primer layer 2 is not particularly limited, and may be any of the conventionally known methods.
For example, the undercoat layer 2 can be formed by applying the undercoat agent onto the support 1 by a conventionally known method such as spin coating or using a spinner to form a coating film, and then drying the coating film.
The method for drying the coating film may be any method capable of volatilizing the solvent contained in the undercoat agent, such as a baking method. In this case, the baking temperature is preferably 80 to 300° C., more preferably 180 to 270° C., and further preferably 220 to 250° C. The baking time is preferably 30 to 500 seconds, and more preferably 60 to 400 seconds.
The thickness of the undercoat layer 2 after the coating film has dried is preferably about 10 to 100 nm, and more preferably about 40 to 90 nm.

The surface of the support 1 may be washed before forming the primer layer 2 on the support 1. Washing the surface of the support 1 improves the coatability of the primer.
The cleaning treatment may be carried out by any of the conventional methods known in the art, including, for example, oxygen plasma treatment, ozone oxidation treatment, acid-alkali treatment, and chemical modification treatment.

After forming the undercoat agent layer 2, the undercoat agent layer 2 may be rinsed with a rinsing liquid such as a solvent, if necessary. The rinsing removes uncrosslinked portions and the like in the undercoat agent layer 2, improving the affinity with at least one block constituting the block copolymer, and facilitating the formation of a phase-separated structure consisting of cylindrical structures oriented in a direction perpendicular to the surface of the support 1.
The rinse liquid may be any liquid capable of dissolving the uncrosslinked portion, and examples of the rinse liquid include solvents such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethyl lactate (EL), and mixtures of two or more of these solvents, and commercially available thinners.
After the cleaning, post-baking may be performed to volatilize the rinsing liquid. The temperature conditions for this post-baking are preferably 80 to 300° C., more preferably 90 to 270° C., and even more preferably 100 to 250° C. The baking time is preferably 30 to 500 seconds, and more preferably 60 to 240 seconds. The thickness of the undercoat agent layer 2 after such post-baking is preferably about 1 to 10 nm, and more preferably about 2 to 7 nm.

Next, a layer containing a (BCP) component (BCP layer) 3 is formed on the undercoat agent layer 2 .
The method for forming the BCP layer 3 on the undercoat layer 2 is not particularly limited, and examples of the method include a method in which the resin composition for forming an etching mask pattern of the above-mentioned embodiment is applied onto the undercoat layer 2 by a conventionally known method such as using spin coating or a spinner to form a coating film, and then drying.

The thickness of the BCP layer 3 may be sufficient to form an etching mask pattern, and is preferably 25 nm or more, more preferably 30 nm or more, and even more preferably 36 nm or more. The upper limit of the thickness of the BCP layer 3 may be, for example, 100 nm or less, preferably 90 nm or less, more preferably 80 nm or less, even more preferably 70 nm or less, and particularly preferably 60 nm or less. For example, when the support 1 is a Si substrate, the thickness of the BCP layer 3 is preferably adjusted to 25 to 100 nm, more preferably 30 to 90 nm, even more preferably 30 to 80 nm, and particularly preferably 30 to 60 nm.

[Step (ii)]
In the step (ii), the BCP layer 3 formed on the support 1 is subjected to phase separation.
By heating the support 1 after step (i) to perform an annealing treatment, the block copolymer is selectively removed to form a phase-separated structure that exposes at least a part of the surface of the support 1. That is, a structure 3' including a phase-separated structure separated into a phase 3a and a phase 3b is produced on the support 1.
The temperature condition of the annealing treatment is preferably equal to or higher than the glass transition temperature of the (BCP) component used and lower than the thermal decomposition temperature, and for example, when the block copolymer is a polystyrene-polymethyl methacrylate (PS-PMMA) block copolymer (mass average molecular weight 5000 to 100000), the temperature is preferably 180 to 270° C. The heating time is preferably 30 to 3600 seconds.
Moreover, the annealing process is preferably carried out in a gas with low reactivity, such as nitrogen.

According to the method for producing an etching mask pattern of the embodiment described above, since the resin composition for forming an etching mask pattern of the above-mentioned embodiment is used, a structure containing a vertically oriented phase separation structure can be obtained with a film thickness sufficient for forming an etching mask pattern (for example, a film thickness of 25 nm or more, preferably a film thickness of 30 nm or more). Therefore, an etching mask pattern can be produced using the structure containing the phase separation structure.

[Optional steps]
The method for producing a structure containing a phase-separated structure is not limited to the above-described embodiment, and may include steps (optional steps) other than steps (i) and (ii).

Such optional steps include a step of selectively removing a phase of the BCP layer 3 that is made up of at least one type of block from the first block and the second block that constitute the (BCP) component (hereinafter referred to as "step (iii)"), a guide pattern formation step, etc.

Regarding step (iii), in the step (iii), a phase consisting of at least one of the first block and the second block constituting the (BCP) component in the BCP layer formed on the undercoat agent layer 2 is selectively removed, thereby forming an etching mask pattern.

As a method for selectively removing a phase consisting of any one of the blocks, there is a method for subjecting the BCP layer to an oxygen plasma treatment, a method for subjecting the BCP layer to a hydrogen plasma treatment, or the like.
For example, after phase separation of a BCP layer containing the (BCP) component, the BCP layer is subjected to oxygen plasma treatment, hydrogen plasma treatment, or the like, whereby the phase consisting of the first block is not selectively removed, but the phase consisting of the second block is selectively removed.

FIG. 2 shows an example embodiment of step (iii).
In the embodiment shown in Figure 2, the structure 3' produced on the support 1 in step (ii) is subjected to an oxygen plasma treatment to selectively remove the phase 3a and form an etching mask pattern consisting of spaced apart phases 3b, where the phase 3b is the phase consisting of the first block and the phase 3a is the phase consisting of the second block.

The etching mask pattern obtained as described above can be used as it is for etching a substrate, but by further heating it, the shape of the etching mask pattern on the substrate 1 can be changed.
The heating temperature is preferably equal to or higher than the glass transition temperature of the block copolymer used and lower than its thermal decomposition temperature, and is preferably carried out in a gas with low reactivity such as nitrogen.

Regarding the guide pattern forming step, the method for producing a structure containing a phase-separated structure may include a step of providing a guide pattern on the undercoat agent layer (guide pattern forming step) prior to the above-mentioned steps (i) and (ii). This makes it possible to control the arrangement structure of the phase-separated structure.
For example, even in the case of a block copolymer in which a random fingerprint-like phase separation structure is formed when no guide pattern is provided, a phase separation structure oriented along the grooves can be obtained by providing a groove structure of the resist film on the surface of the undercoat layer. Based on this principle, a guide pattern may be provided on the undercoat layer 2. In addition, if the surface of the guide pattern has affinity with any of the blocks constituting the (BCP) component, a phase separation structure oriented perpendicular to the support surface is easily formed.

The guide pattern can be formed using, for example, a resist composition.
The resist composition for forming the guide pattern can be appropriately selected from resist compositions generally used for forming resist patterns and their modifications, and can be used by selecting one that has affinity with any of the blocks constituting the (BCP) component. The resist composition may be either a positive resist composition for forming a positive pattern in which the exposed portion of the resist film is dissolved and removed, or a negative resist composition for forming a negative pattern in which the unexposed portion of the resist film is dissolved and removed, but is preferably a negative resist composition. As the negative resist composition, for example, a resist composition containing an acid generator and a base material component whose solubility in a developer containing an organic solvent is reduced by the action of an acid, and the base material component contains a resin component having a structural unit that is decomposed by the action of an acid to increase polarity, is preferred.
After the resin composition for forming an etching pattern is poured onto the undercoat layer on which the guide pattern is formed, an annealing treatment is performed to cause phase separation. Therefore, it is preferable that the resist composition for forming the guide pattern is one capable of forming a resist film having excellent solvent resistance and heat resistance.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

(Synthesis of BCP precursor: BCP precursor (1))
All anionic polymerizations were carried out under an argon atmosphere. 30 mL of tetrahydrofuran (THF) and lithium chloride (LiCl) (21.2 mg, 0.500 mmol) were transferred to a 50 mL Schlenk flask and cooled to −78° C. in a cool-nic bath. Sec-butyllithium (Sec-BuLi) (1.05 M in hexane/cyclohexane) was added to the Schlenk flask until the solution turned yellow in color. The Schlenk flask was removed from the cool-nic bath and warmed at room temperature until the solution became colorless. The Schlenk flask was again cooled to −78° C. in a cool-nic bath and sec-BuLi (0.095 mL, 0.100 mmol) was added as initiator. Styrene (1.03 mL, 9.04 mmol) was added and stirred for 30 min. This resulted in a bright orange solution. 1,1-diphenylethylene (DPE) (0.088 mL, 0.50 mmol) was added, and the color of the solution changed to deep red. After stirring for 30 minutes, a monomer mixture of methyl methacrylate (MMA) (0.80 mL, 7.50 mmol) and glycidyl methacrylate (GMA) (0.325 mL, 2.50 mmol) was added and stirred for 30 minutes. The color of the solution changed from red to transparent. As a terminator, 3 mL of degassed methanol (MeOH) was added to the Schlenk flask to terminate the polymerization. The Schlenk flask was removed from the Coolnics bath, and the solution was poured into MeOH to perform reprecipitation. The precipitated solid was filtered and then dried under reduced pressure at 40° C. to obtain a white powder of BCP precursor (1) (1.76 g, 88% yield).

(Synthesis of Block Copolymer: BCP(1))
A 10 mL glass tube was charged with 0.2 g of BCP precursor (1) and THF (20 wt % solution) and immersed in an ice-water bath. 1 wt % lithium hydroxide (LiOH) aqueous solution (0.05 mole equivalents of LiOH/GMA unit) and 2,2,2-trifluoroethanethiol (2 mole equivalents/GMA unit) were added to the glass tube. After stirring at room temperature for 20 minutes, the reactor was set to 40° C. and stirred for 3 hours to synthesize BCP (1). Depending on the Mn and PHFMA fraction of the synthesized BCP (1), the product was repeatedly precipitated with methanol or methanol/hexane several times to remove residual reagents. The product was dried overnight at room temperature under reduced pressure to obtain a white powder of BCP (1). The Mn and polydispersity (PDI = Mw/Mn) of BCP (1) measured by size exclusion chromatography (SEC) were 23,000 g·mol ⁻¹ and 1.05, respectively.
^1H NMR (400MHz, Acetone-d ₆ , δ, ppm): 0.84 (s, α-CH ₃ , PMMA), 0.87 (s, α-CH ₃ , PMMA), 1.00 (s, α-CH ₃ , PMMA), 1.03 (s, α-CH ₃ , PHFMA), 1.23-1.73 (br, backbone, -CH ₂ -CH-, PS), 1.75-2.23 (br, backbone, -CH ₂ -CH-, PS, br, backbone, -CH ₂ -C (CH ₃ )-, PHFMA and PMMA) .00(d,CH(OH) _-CH2 -S-, PHFMA), 3.40-3.77 (s, -S-CH ₂ -CF ₃ , PHFMA), 3.54-3.75 (s, -OCH ₃ , PMMA), 3.92-4.07 (d, -(C=O)O-CH ₂ -, PHFMA), 4.07-4.18 (m, -CH (O H)-, PHFMA) 4.50-4.72 (br, -CH(OH)-, PHFMA), 6.36-6.84 (m, o-aromatic, PS), 6.85-7.35 (m, m-, p-aromatic, PS).

(Synthesis of Block Copolymer: BCP(2))
BCP precursor (2) was synthesized in the same manner as in the synthesis of BCP precursor (1) except that the amount of styrene used was 2.71 mL (23.8 mmol), the amount of MMA used was 0.91 mL (8.5 mmol), and the amount of GMA used was 0.065 mL (0.5 mmol). Next, BCP (2) was synthesized in the same manner as in the synthesis of BCP (1) except that BCP precursor (2) was used instead of BCP precursor (1). The Mn and polydispersity (PDI = Mw / Mn) of BCP (2) measured by size exclusion chromatography (SEC) were 33000 g mol ^-1 and 1.05, respectively.

(Measurement of the volume of each block)
The mole percentage of each block in the block copolymer was calculated from the results of ¹ H NMR analysis, and the mass percentage of each block was calculated. The mass percentage of each block was then divided by the density of each block to calculate the volume ratio of each block. From the volume ratio, the ratio of the volume of the polystyrene block to the total volume of the block copolymer was calculated. The density of each block was estimated by the atomic group contribution method (Fedors, RF Polym. Eng. Sci. 1974, 14,147-154.). The density of the polystyrene block was 1.05 gm ⁻³ . The density of the structure composed of structural units derived from methyl methacrylate was 1.18 gcm ⁻³ . The density of the structure composed of structural units derived from 2-hydroxy-3-(2,2,2-trifluoroethylsulfanyl)propyl methacrylate was 1.43 gcm ⁻³ .

Table 1 shows the number average molecular weight (Mn), polydispersity (PDI = Mw/Mn), volume ratio (vol %) of the polystyrene block (PS) to the total volume of the block copolymer, and the value of x in the reaction formula above.

(Preparation of Base)
The components shown in Table 2 were mixed and dissolved to prepare each of the base agents NL-1 to NL-3 (solid content concentration: 1% by mass).

In Table 2, each abbreviation has the following meaning. The value in [ ] is the blend amount (parts by mass). The number average molecular weight (Mn) of each polymer was determined by size exclusion chromatography (SEC). The copolymerization composition ratio of each polymer (the ratio (molar ratio) of each structural unit in the structural formula) was determined by ^3C -NMR.
(P)-1: A polymer represented by the following chemical formula (P-1). Mn=24,000. l/m/n=39/56/5.
(P)-2: A polymer represented by the following chemical formula (P-1). Mn=28,000. l/m/n=49/46/5.
(P)-3: A polymer represented by the following chemical formula (P-1). Mn=30,000. l/m/n=61/34/5.
(S)-1: Propylene glycol monomethyl ether acetate (PGMEA).

In Table 2, "Water contact angle (°)" was measured as follows.
A primer layer was formed in the same manner as in "Formation of primer layer" described later. Water (2 μL) was dropped onto the surface of the primer layer, and the contact angle (static contact angle) was measured using DROP MASTER-700 (product name, manufactured by Kyowa Interface Science Co., Ltd.).

(Examples 1 to 3, Comparative Example 1)
<Preparation of Resin Composition for Forming Etching Mask Pattern>
The components shown in Table 3 were mixed and dissolved to prepare a resin composition for forming an etching mask pattern (solid content concentration: 1.25% by mass) of each example.

In Table 3, the abbreviations have the following meanings. The numbers in brackets [ ] indicate the blend amount (parts by mass).
BCP-1: the BCP (1).
PS-2k: polystyrene. The number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 2000.
PMMA-2k: Polymethylmethacrylate, with a number average molecular weight (Mn) of 2000 as measured by size exclusion chromatography (SEC).
(S)-1: PGMEA.

<Production of Etching Mask Pattern (1)>
After forming a base layer on a wafer using the base agent NL-1, an etching mask pattern was obtained using the resin composition for forming an etching mask pattern of each of the above examples by a manufacturing method having the steps (i) to (iii) shown below.

Formation of the primer layer:
The above-mentioned undercoat agent NL-1 was spin-coated onto a silicon substrate, and then heated at 250° C. for 5 minutes in an air atmosphere. Next, the substrate was rinsed with a mixed solvent of propylene glycol monomethyl ether (PGME)/propylene glycol monomethyl ether acetate (PGMEA) (PGME/MGMEA=7/3 (mass ratio)). Next, the substrate was heated at 100° C. for 1 minute. As a result, a 5 nm-thick undercoat agent layer made of the undercoat agent NL-1 was formed on the substrate surface.

Step (i):
Onto the above undercoat agent layer, the resin composition for forming an etching mask pattern of each example was spin-coated to a film thickness of 36 nm to form a resin composition layer (a layer containing a block copolymer).

Step (ii):
The resin composition layer formed on the undercoat layer was prebaked at 90° C. for 60 seconds in a nitrogen atmosphere, and then annealed at 240° C. for 5 minutes in a nitrogen atmosphere to form a phase-separated structure.

Step (iii):
The substrate on which the phase-separated structure was formed was subjected to oxygen plasma treatment (200 mL/min, 40 Pa, 40° C., 200 W, 10 seconds) using TCA-3822 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) to selectively remove the phase made of PMMA.

[Evaluation of Resolution]
The surface (phase-separated state) of the obtained substrate was observed with a length-measuring SEM (scanning electron microscope, product name: CG6300, manufactured by Hitachi High-Technologies Corporation), and the formation of a microphase-separated structure (lamellar structure) was confirmed.
As a result of such observation, the resolution was evaluated based on the following evaluation criteria. The results are shown in Table 4 as "resolution".
(Evaluation Criteria)
A: A microphase-separated structure without any disconnections was observed over the entire surface.
B: Disconnection was observed in part of the microphase-separated structure.
C: No microphase-separated structure was observed.

[Evaluation of vertical alignment]
The surface (phase-separated state) of the obtained substrate was observed with a length-measuring SEM (scanning electron microscope, product name: CG6300, manufactured by Hitachi High-Technologies Corporation).
As a result of such observation, the vertical alignment of the etching pattern was evaluated based on the following evaluation criteria. The results are shown in Table 3 as "vertical alignment".
(Evaluation Criteria)
A: A vertical lamellar pattern is formed over the entire surface.
B: Vertical lamellar pattern is partially formed.
C: No terrace structure or pattern.

From the results shown in Table 4, in Examples 1 to 3, etching mask patterns with good resolution and vertical alignment were formed. On the other hand, in Comparative Example 1, a vertical lamellar pattern could not be formed, and an etching mask pattern could not be formed.

(Examples 4 to 8, Comparative Examples 2 to 4)
<Preparation of Resin Composition for Forming Etching Mask Pattern>
The components shown in Table 5 were mixed and dissolved to prepare a resin composition for forming an etching mask pattern (solid content concentration: 1.25% by mass) of each example.

In Table 5, the abbreviations have the following meanings. The numbers in brackets [ ] indicate the blend amount (parts by mass).
BCP-1: the BCP (1).
PS-2k: polystyrene. The number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 2000.
PS-1.5k: polystyrene. The number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 1,500.
PS-3k: polystyrene. The number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 3,000.
PS-5k: polystyrene. The number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 5,000.
PMMA-2k: Polymethylmethacrylate, with a number average molecular weight (Mn) of 2000 as measured by size exclusion chromatography (SEC).
PMMA-1.5k: Polymethylmethacrylate, number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 1500.
PMMA-3k: Polymethylmethacrylate, with a number average molecular weight (Mn) of 3,000 as measured by size exclusion chromatography (SEC).
PMMA-5k: Polymethylmethacrylate, number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 5000.
(S)-1: PGMEA.

<Production of Etching Mask Pattern (2)>
An etching mask pattern was formed in the same manner as in <Production of Etching Mask Pattern (1)> above, except that the above-mentioned base agent NL-1 or NL-2 was used as the base agent.

[Evaluation of Resolution]
The resolution of the etching pattern formed using each of the resin compositions for forming an etching mask pattern was evaluated in the same manner as above. The results are shown in Table 6 as "resolution".

[Evaluation of vertical alignment]
The vertical alignment property of the etching pattern formed using each of the resin compositions for forming an etching mask pattern was evaluated in the same manner as above. The results are shown in Table 6 as "vertical alignment property".

From the results shown in Table 6, in Examples 4 to 8, an etching mask pattern with good resolution and vertical alignment was formed regardless of which base agent was used. On the other hand, in Comparative Example 1, a vertical lamellar pattern could not be formed regardless of which base agent was used, and an etching mask pattern could not be formed.

(Examples 9 to 10, Comparative Examples 5 to 7)
<Preparation of Resin Composition for Forming Etching Mask Pattern>
The components shown in Table 7 were mixed and dissolved to prepare a resin composition for forming an etching mask pattern (solid content concentration: 1.25% by mass) of each example.

In Table 7, the abbreviations have the following meanings. The numbers in brackets [ ] indicate the blend amount (parts by mass).
BCP-2: the BCP (2).
BCP-3: Block copolymer BCP(3) (PS-b-PMMA) shown below. The number average molecular weight (Mn), polydispersity (PDI=Mw/Mn) of the block copolymer, and the volume ratio (volume %) of the polystyrene block (PS) to the total volume of the block copolymer are summarized in Table 8.

PS-2k: polystyrene. The number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 2000.
PMMA-2k: Polymethylmethacrylate, with a number average molecular weight (Mn) of 2000 as measured by size exclusion chromatography (SEC).
(S)-1: PGMEA.

<Production of Etching Mask Pattern (3)>
An etching mask pattern was formed in the same manner as in <Production of Etching Mask Pattern (1)> above, except that the undercoat agent NL-3 was used as the undercoat agent and the annealing temperature was set to 220°C.

[Evaluation of Resolution]
The surface (phase-separated state) of the obtained substrate was observed with a length-measuring SEM (scanning electron microscope, product name: CG6300, manufactured by Hitachi High-Technologies Corporation), and the formation of a microphase-separated structure (cylinder structure) was confirmed.
As a result of such observation, the resolution was evaluated based on the following evaluation criteria. The results are shown in Table 4 as "resolution".
(Evaluation Criteria)
A: A microphase-separated structure without any disconnections was observed over the entire surface.
B: Disconnection was observed in part of the microphase-separated structure.
C: No microphase-separated structure was observed.

[Evaluation of vertical alignment]
The surface (phase-separated state) of the obtained substrate was observed with a length-measuring SEM (scanning electron microscope, product name: CG6300, manufactured by Hitachi High-Technologies Corporation).
As a result of such observation, the vertical alignment of the etching pattern was evaluated based on the following evaluation criteria. The results are shown in Table 9 as "vertical alignment".
(Evaluation Criteria)
A: A vertical cylinder pattern is formed over the entire surface.
B: A vertical cylinder pattern is partially formed.
C: No terrace structure or pattern.

From the results shown in Table 9, in Examples 9 to 10, etching mask patterns with good resolution and vertical alignment were formed. On the other hand, in Comparative Examples 5 to 7, a vertical cylinder pattern could not be formed, and an etching mask pattern could not be formed.

(Synthesis of Block Copolymer: BCP(4))
BCP (4) was synthesized in the same manner as above (Synthesis of block copolymer: BCP (1)), except that ethanethiol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (4) measured by size exclusion chromatography (SEC) were 23,000 g mol ^-1 and 1.05, respectively.
^1H NMR (400MHz, CDCl ₃ , δ, ppm): 0.85-1.02 (α-CH ₃ , PMMA, PGEMA, -S-CH ₂ -CH ₃ , PGEMA,), 1.23-1.69 (-CH ₂ -CH-, PS backbone), 1.74 -2.02 (-CH ₂ -CH-, PS backbone, -CH ₂ -C(CH ₃ )-, PGEMA and PMMA), 2.63 (-CH(OH)-CH ₂ -S-CH ₂ -CH ₃ , PGEMA), 3.60 (-O-CH ₃ , PMMA), 3. 99(-(C=O)O- _CH2 -CH(OH), PGEMA), 6.39-6.85 (o-aromatic, PS), 6.91-7.42 (p-, m-aromatic, PS).

(Synthesis of Block Copolymer: BCP(5))
BCP (5) was synthesized in the same manner as above (Synthesis of block copolymer: BCP (2)), except that ethanethiol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (5) measured by size exclusion chromatography (SEC) were 33,000 g mol ^-1 and 1.05, respectively.

(Synthesis of Block Copolymer: BCP(6))
BCP (6) was synthesized in the same manner as above (Synthesis of block copolymer: BCP (1)), except that 1-propanethiol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (6) measured by size exclusion chromatography (SEC) were 23,000 g mol ^-1 and 1.05, respectively.
^1H NMR (400MHz, CDCl ₃ , δ, ppm): 0.85-1.02 (α-CH ₃ , PMMA, PGPMA, -S-CH ₂ -CH ₂ -CH ₃ , PGPMA,), 1.23-1.69 (-S-CH ₂ -CH ₂ -CH ₃ , P GPMA, -CH ₂ -CH-, PS backbone), 1.74-2.02 (-CH ₂ -CH-, PS backbone, -CH ₂ -C(CH ₃ )-, PGPMA and PMMA), 2.63 (-CH(OH)-CH ₂ -S-CH ₂ -CH _2- , PGPMA), 3.60(-O- _CH3 , PMMA), 3.99 (-(C=O)O-CH ₂ -CH(OH), PGPMA), 6.39-6.85 (o-aromatic, PS), 6.91-7.42 (p-, m-aromatic, PS).

(Synthesis of Block Copolymer: BCP(7))
BCP (7) was synthesized in the same manner as in the above (Synthesis of block copolymer: BCP (2)), except that 1-propanethiol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (7) measured by size exclusion chromatography (SEC) were 33,000 g mol ^-1 and 1.05, respectively.

(Synthesis of Block Copolymer: BCP(8))
BCP (8) was synthesized in the same manner as above (Synthesis of block copolymer: BCP (1)), except that 1-hexanethiol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (8) measured by size exclusion chromatography (SEC) were 23,000 g mol ^-1 and 1.05, respectively.
^1H NMR (400MHz, CDCl ₃ , δ, ppm): 0.85-1.02 (α-CH ₃ , PMMA, PGHMA, -CH ₂ -CH ₂ -CH ₃ , PGHMA,), 1.23-1.69 (-S-CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -, PGHMA, -CH ₂ -CH-, PS backbone), 1.74-2.02 (-CH ₂ -CH-, PS backbone, -CH ₂ -C(CH ₃ )-, PGHMA and PMMA), 2.63 (-CH(OH)-CH ₂ -S-CH ₂ -CH ₂ -, PGHMA), 3.60 (-O-CH ₃ , PMMA), 3.99 (-(C=O)O-CH ₂ -CH(OH), PGHMA), 6.39-6.85 (o-aromatic, PS), 6.91-7.42 (p-, m-aromatic, PS).

(Synthesis of Block Copolymer: BCP(9))
BCP (9) was synthesized in the same manner as above (Synthesis of block copolymer: BCP (2)), except that 1-hexanethiol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (9) measured by size exclusion chromatography (SEC) were 33,000 g mol ^-1 and 1.05, respectively.

(Synthesis of Block Copolymer: BCP(10))
BCP (10) was synthesized in the same manner as above (Synthesis of block copolymer: BCP (1)), except that cyclohexanethiol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (10) measured by size exclusion chromatography (SEC) were 23,000 g mol ^-1 and 1.05, respectively.
¹ H NMR (400 MHz, CDCl ₃ , δ, ppm): 0.85-1.02 (α-CH ₃ , PMMA, PGCMA), 1.23-1.69 (-S-CH(CH ₂ -CH ₂ )-CH ₂ -CH ₂ -CH ₂ -, PGCMA, -CH ₂ -CH-, PS backbone), 1.74-2.02 (-S-CH (CH ₂ -CH ₂ ) -CH ₂ -CH ₂ -CH ₂ -, PGCMA, -CH ₂ -CH-, PS backbone, -CH ₂ -C(CH ₃ )-, PGCMA and PMMA), 2.63(-CH(OH)-CH ₂ -S-CH(CH ₂ -CH ₂ )-CH ₂ -CH ₂ -CH ₂ -, PGCMA), 3.60 (-O-CH ₃ , PMMA), 3.99 (-(C=O)O-CH ₂ -CH(OH), PGCMA), 6.39-6.85 (o-aromatic, PS), 6.91-7.42 (p-, m-aromatic, PS).

(Synthesis of Block Copolymer: BCP(11))
BCP (11) was synthesized in the same manner as in (Synthesis of block copolymer: BCP (2)) except that cyclohexanethiol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (11) measured by size exclusion chromatography (SEC) were 33,000 g mol ^-1 and 1.05, respectively.

(Measurement of the volume of each block)
The volume ratio of each block was calculated in the same manner as above. From the volume ratio, the proportion of the volume of the polystyrene block in the total volume of the block copolymer was calculated in the same manner as above. In block copolymers (4) to (11), the density of the structure composed of a structural unit corresponding to the structural unit (b2g) (structural unit having a sulfide group) was always 1.18 g cm ^-3 .

The number average molecular weight (Mn), polydispersity (PDI = Mw/Mn), volume ratio (vol %) of the polystyrene block (PS) to the total volume of the block copolymer, and the value of x in the above reaction formula are summarized in Table 10.

(Examples 11 to 30, Comparative Examples 8 to 15)
<Preparation of Resin Composition for Forming Etching Mask Pattern>
The components shown in Tables 11 and 12 were mixed and dissolved to prepare resin compositions for forming etching mask patterns (solid content concentration: 1.25% by mass).

In Tables 11 and 12, the abbreviations have the following meanings. The numbers in brackets [ ] are the amounts blended (parts by mass).
BCP-4 to BCP-11: the aforementioned BCPs (4) to BCPs (11).
PS-2k: polystyrene. The number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 2000.
PMMA-2k: Polymethylmethacrylate, with a number average molecular weight (Mn) of 2000 as measured by size exclusion chromatography (SEC).
(S)-1: PGMEA.

<Manufacture of Etching Mask Pattern>
An etching mask pattern was formed in the same manner as in <Production of Etching Mask Pattern (1)> above.

[Evaluation of Resolution]
The resolution of the etching pattern formed using the resin composition for forming an etching mask pattern of each example was evaluated in the same manner as described above (Examples 1 to 3, Comparative Example 1). The results are shown in Tables 13 to 14 as "resolution".

[Evaluation of vertical alignment]
The surface (phase-separated state) of the obtained substrate was observed with a length-measuring SEM (scanning electron microscope, product name: CG6300, manufactured by Hitachi High-Technologies Corporation).
As a result of such observation, the vertical alignment of the etching pattern was evaluated based on the following evaluation criteria. The results are shown in Tables 13 to 14 as "vertical alignment".
(Evaluation Criteria)
A: A vertical lamellar pattern is formed over the entire surface.
B: Vertical lamellar pattern is partially formed.
C: No terrace structure or pattern.

From the results shown in Tables 13 to 14, in Examples 11 to 30, etching mask patterns with good resolution and vertical alignment were formed. On the other hand, in Comparative Examples 8 to 15, a vertical lamellar pattern could not be formed, and an etching mask pattern could not be formed.

(Synthesis of Block Copolymer: BCP(12))
BCP (12) was synthesized in the same manner as in the above (Synthesis of block copolymer: BCP (1)), except that 3-mercapto-1-hexanol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (12) measured by size exclusion chromatography (SEC) were 23,000 g mol ^-1 and 1.05, respectively.
^1H NMR (400MHz, CDCl ₃ , δ, ppm): 0.71-1.05 (α-CH ₃ , PMMA and PGOMA, -S-CH-CH ₂ -CH ₂ -CH ₃ , PGOMA), 1.43-2.02 (-S-CH-CH ₂ -CH ₂ -CH ₃ , PGOMA, -S-CH-CH ₂ -CH ₂ -OH, PGOMA, -CH ₂ -CH-, PS backbone, -CH ₂ -C(CH ₃ )-, PGOMA and PMMA), 2.68-2.88(-CH(OH)-CH2- _S -CH(-,PGOMA),3.60(-O- _CH3 , PMMA), 3.73 (-S-CH-CH ₂ -CH ₂ -OH, PGOMA), 4.08 (-(C=O)O-CH ₂ -CH(OH), PGOMA), 6.39-6.85 (o-aromatic, PS), 6.91-7.42 (p-, m-aromatic, PS).

(Synthesis of Block Copolymer: BCP(13))
BCP (13) was synthesized in the same manner as in the above (Synthesis of block copolymer: BCP (2)), except that 3-mercapto-1-hexanol was used instead of 2,2,2-trifluoroethanethiol. The Mn and polydispersity (PDI = Mw/Mn) of BCP (13) measured by size exclusion chromatography (SEC) were 33,000 g mol ^-1 and 1.05, respectively.

(Measurement of the volume of each block)
The volume ratio of each block was calculated in the same manner as above. From the volume ratio, the proportion of the volume of the polystyrene block in the total volume of the block copolymer was calculated in the same manner as above. In block copolymers (12) to (13), the density of the structure constituted by the constituent unit corresponding to the constituent unit (b2g) (constituent unit having a sulfide group) was always 1.18 g cm ^-3 .

The number average molecular weight (Mn), polydispersity (PDI = Mw/Mn), volume ratio (vol %) of the polystyrene block (PS) to the total volume of the block copolymer, and the value of x in the above reaction formula are summarized in Table 15.

(Examples 31 to 35, Comparative Examples 16 and 17)
<Preparation of Resin Composition for Forming Etching Mask Pattern>
The components shown in Tables 16 and 17 were mixed and dissolved to prepare resin compositions for forming etching mask patterns (solid content concentration: 1.25% by mass).

In Tables 16 and 17, the abbreviations have the following meanings. The numbers in brackets [ ] are the blend amounts (parts by mass).
BCP-12 to BCP-13: The above BCP (12) to BCP (13).
PS-2k: polystyrene. The number average molecular weight (Mn) measured by size exclusion chromatography (SEC) is 2000.
PMMA-2k: Polymethylmethacrylate, with a number average molecular weight (Mn) of 2000 as measured by size exclusion chromatography (SEC).
(S)-1: PGMEA.

<Manufacture of Etching Mask Pattern>
In Comparative Example 16 and Examples 31 to 33, etching mask patterns were formed in the same manner as in <Production of Etching Mask Pattern (1)> above.

For Comparative Example 17 and Examples 34 to 35, the etching mask patterns were formed in the same manner as described above in <Production of Etching Mask Pattern (3)>.

[Evaluation of Resolution]
The resolution of the etching pattern formed using the resin composition for forming an etching mask pattern of each example was evaluated in the same manner as described above (Examples 1 to 3, Comparative Example 1). The results are shown in Tables 18 and 19 as "resolution".

[Evaluation of vertical alignment]
The surface (phase-separated state) of the obtained substrate was observed with a length-measuring SEM (scanning electron microscope, product name: CG6300, manufactured by Hitachi High-Technologies Corporation).
As a result of such observation, the vertical alignment of the etching pattern was evaluated based on the following evaluation criteria. The results are shown in Tables 18 and 19 as "vertical alignment".
(Evaluation Criteria)
A: A vertical lamellar pattern is formed over the entire surface.
B: Vertical lamellar pattern is partially formed.
C: No terrace structure or pattern.

From the results shown in Tables 18 and 19, in Examples 31 to 35, etching mask patterns with good resolution and vertical alignment were formed. On the other hand, in Comparative Examples 16 to 17, a vertical lamellar pattern could not be formed, and an etching mask pattern could not be formed.

DESCRIPTION OF SYMBOLS 1... Support body, 2... Base layer, 3... BCP layer, 3'... Structure, 3a... Phase, 3b... Phase.

Claims (6)

A resin composition for forming an etching mask pattern, comprising a block copolymer having a first block and a second block, and a homopolymer having a number average molecular weight of less than 3,000,
The first block is composed of a polymer having a repeating structure of a structural unit represented by the following general formula (b1):
The second block is composed of a random copolymer having a structure in which a constitutional unit represented by the following general formula (b2m) and a constitutional unit represented by the following general formula (b2g) are randomly arranged,
a ratio of a volume of the first block to a total volume of the first block and the second block is 20 to 80 volume %,
The homopolymer includes a polymer having a repeating structure of a structural unit represented by the following general formula (b1):
A resin composition for forming an etching mask pattern.

In formula (b1), R ¹ is an alkyl group. R ^b1 is a hydrogen atom or a methyl group. n is an integer of 0 to 5. When n is an integer of 2 or more, the multiple R ^1s may be the same or different.
In formula (b2g), ^R2 is an alkyl group which may have a silicon atom, a fluorine atom, a carboxy group, an amino group, a cyano group, a hydroxy group or a phosphate group.
^R3 is a linear or branched alkylene group having 1 to 10 carbon atoms which may have a hydroxyl group.
In formulae (b2g) and (b2m), R ^b2 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Multiple R ^b2 may be the same or different.
x represents a molar ratio and is greater than 0 and less than 1. The resin composition for forming an etching mask pattern according to claim 1, wherein the homopolymer further contains a polymer having a repeating structure of the structural unit represented by the general formula (b2m). The resin composition for forming an etching mask pattern according to claim 1 or 2, wherein the homopolymer has a number average molecular weight of 1000 or more. The resin composition for forming an etching mask pattern according to claim 1 or 2, wherein the content of the homopolymer is 10 to 50 parts by mass per 100 parts by mass of the block copolymer. A step of applying the resin composition for forming an etching mask pattern according to claim 1 or 2 onto a support to form a layer containing a block copolymer;
allowing the layer containing the block copolymer to phase separate;
The method for producing an etching mask pattern includes the steps of: The method for producing an etching mask pattern according to claim 5, wherein the layer containing the block copolymer is formed to a thickness of 25 nm or more.

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