JP2022065445A - Resist material, resist film, and pattern forming method - Google Patents

Abstract

To provide a resist material capable of forming a highly sensitive resist film.SOLUTION: The present invention relates to the resist material containing a polymer which contains a unit derived from a structure represented by general formula (101) and a unit derived from a structure represented by general formula (104). The resist material of the present invention may further have a unit derived from a structure represented by general formula (102) and/or a unit derived from a structure represented by general formula (103).SELECTED DRAWING: None

Description

The present invention relates to a resist material, a resist film and a pattern forming method.

Electronic devices such as semiconductors are required to have higher definition by miniaturization. In addition, diversification of shapes of semiconductor device patterns is also being studied. As a method for forming such a pattern, for example, a lithography method using a photoresist is known. In the lithography method using a photoresist, a resist film is formed on a semiconductor substrate such as a silicon wafer, and an electromagnetic wave such as ultraviolet rays is irradiated through a photomask on which a pattern of a semiconductor device is drawn to develop the resist film. By etching the substrate using the photoresist pattern as a protective film, fine irregularities corresponding to the pattern can be formed on the substrate.

As the resist material constituting the resist film, polymers having various structures are used depending on the use and required physical properties. For example, as a polymer used as a resist material, a polymer containing a structural unit derived from (meth) acrylate is known. In Patent Documents 1 to 3, it is considered to use a polymer obtained by copolymerizing α-methylstyrene with methacrylic acid or a methacrylic acid ester as a resist material.

Further, in Patent Document 4, it is studied to use a polymer obtained by polymerizing an adamantyl methacrylate monomer and a t-butyl monomer acrylate as a radiation photosensitive material. In this way, two specific types of monomer components are copolymerized to form a resist material to form a resist film. Patent Document 5 discloses a resist material using an acrylic acid ester resin containing a fluorinated alkyl group in the ester side chain as a base polymer. The resist material in Patent Document 5 is a chemically amplified resist material used together with a photoacid generator and a basic compound.

Japanese Unexamined Patent Publication No. 60-117243 Japanese Unexamined Patent Publication No. 63-137227 International release WO99 / 62964 Japanese Unexamined Patent Publication No. 07-234511 Japanese Unexamined Patent Publication No. 2002-155118

As described above, in the lithography method using a photoresist, it has been studied to form a fine pattern. In order to form a fine pattern, it is necessary to pattern the resist film with high fineness, and for this reason, the development of a highly sensitive resist material is required.

Therefore, in order to solve the problems of the prior art, the present inventors have proceeded with studies for the purpose of providing a resist material capable of forming a highly sensitive resist film.

As a result of diligent studies to solve the above problems, the present inventors have formed a highly sensitive resist film by using a monomer having a predetermined structure as a polymerization component of the polymer constituting the resist material. I found that.
Specifically, the present invention has the following configurations.

一般式（１０１）中、Ｒ^１は、それぞれ独立に水素原子、置換基を有していてもよいアルキル基、置換基を有していてもよいアシル基、置換基を有していてもよいアリル基、置換基を有していてもよいアルコキシ基又は置換基を有していてもよいアルキルシリル基を表し、複数あるＲ^１は同一であっても異なっていてよい；Ｒ^１１は、水素原子又は置換基を有していてもよいアルキル基を表す；Ｒ^２は、水素原子、アルキル基、フッ素原子、塩素原子、臭素原子又はハロゲン化アルキル基を表し、Ｙ^１は、単結合又は連結基を表す；
一般式（１０４）中、Ｘ^３は、ハロゲン化アルキル基を表し、Ｒ^５は、水素原子、アルキル基、フッ素原子、塩素原子、臭素原子又はハロゲン化アルキル基を表し、Ｙ^４は、単結合又は連結基を表す。
［２］ ポリマーは、下記一般式（１０２）で表される構造に由来する単位をさらに含む［１］に記載のレジスト材料；

一般式（１０２）中、Ｘ^１は、置換基を有していてもよいアルキル基（但し、置換基にハロゲン原子を含むものを除く）、置換基を有していてもよいアシル基又は置換基を有していてもよいアリル基を表す；Ｒ^３は、水素原子、アルキル基、フッ素原子、塩素原子、臭素原子又はハロゲン化アルキル基を表し、Ｙ^２は、単結合又は連結基を表す。
［３］ ポリマーは、下記一般式（１０３）で表される構造に由来する単位をさらに含む［１］又は［２］に記載のレジスト材料；

一般式（１０３）中、Ｘ^２は、置換基を有していてもよいアリール基を表す；Ｒ^４は、水素原子、アルキル基、フッ素原子、塩素原子、臭素原子又はハロゲン化アルキル基を表し、Ｙ^３は、単結合又は連結基を表す。
［４］ ポリマーにおける一般式（１０４）で表される構造に由来する単位の含有量は、１～４０モル％である、［１］～［３］のいずれかに記載のレジスト材料。
［５］ 一般式（１０１）において、Ｒ^２はフッ素原子、塩素原子又は臭素原子である［１］～［４］のいずれかに記載のレジスト材料。
［６］ 一般式（１０１）において、Ｒ^１１は水素原子である［１］～［５］のいずれかに記載のレジスト材料。
［７］ 一般式（１０２）において、Ｒ^３はフッ素原子、塩素原子又は臭素原子である［２］～［６］のいずれかに記載のレジスト材料。
［８］ ［１］～［７］のいずれかに記載のレジスト材料から形成されるレジスト膜。
［９］ ［１］～［７］のいずれかに記載のレジスト材料を基板上に塗布し、レジスト膜を形成する工程と、
露光工程と、
現像工程と、を含むパターン形成方法。
［１０］ 現像工程の前に金属導入工程をさらに含む、［９］に記載のパターン形成方法。
［１１］ 露光工程では、波長が１５ｎｍ以下の電磁波をレジスト膜に照射する、［９］又は［１０］に記載のパターン形成方法。
［１２］ 現像工程で使用される現像液は、エステル系化合物、ケトン系化合物及びアルコール系化合物からなる群から選択される少なくとも１種を含む、［９］～［１１］のいずれかに記載のパターン形成方法。 [1] A resist material containing a polymer containing a unit derived from the structure represented by the following general formula (101) and a unit derived from the structure represented by the following general formula (104);

In the general formula (101), R ¹ may independently have a hydrogen atom, an alkyl group which may have a substituent, an acyl group which may have a substituent, and a substituent. Represents an allyl group, an alkoxy group which may have a substituent or an alkylsilyl group which may have a substituent, and a plurality of R ^1s may be the same or different; R ¹¹ is hydrogen. Represents an alkyl group which may have an atom or a substituent; R ² represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ¹ is a single bond or a link. Represents a group;
In the general formula (104), X ³ represents an alkyl halide group, R ⁵ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ⁴ represents a single bond. Or represents a linking group.
[2] The resist material according to [1], wherein the polymer further contains a unit derived from the structure represented by the following general formula (102);

In the general formula (102), X ¹ is an alkyl group which may have a substituent (excluding those containing a halogen atom in the substituent), an acyl group which may have a substituent or a substituent. Represents an allyl group which may have a group; R ³ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ² represents a single bond or a linking group. ..
[3] The resist material according to [1] or [2], wherein the polymer further contains a unit derived from the structure represented by the following general formula (103);

In the general formula (103), X ² represents an aryl group which may have a substituent; R ⁴ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group. , Y ³ represent a single bond or a linking group.
[4] The resist material according to any one of [1] to [3], wherein the content of the unit derived from the structure represented by the general formula (104) in the polymer is 1 to 40 mol%.
[5] The resist material according to any one of [1] to [4], wherein R ² is a fluorine atom, a chlorine atom or a bromine atom in the general formula (101).
[6] The resist material according to any one of [1] to [5], wherein R ¹¹ is a hydrogen atom in the general formula (101).
[7] The resist material according to any one of [2] to [6], wherein R ³ is a fluorine atom, a chlorine atom or a bromine atom in the general formula (102).
[8] A resist film formed from the resist material according to any one of [1] to [7].
[9] A step of applying the resist material according to any one of [1] to [7] onto a substrate to form a resist film, and
The exposure process and
A development process and a pattern forming method including.
[10] The pattern forming method according to [9], further comprising a metal introduction step before the developing step.
[11] The pattern forming method according to [9] or [10], wherein in the exposure step, the resist film is irradiated with an electromagnetic wave having a wavelength of 15 nm or less.
[12] The developer according to any one of [9] to [11], wherein the developer used in the developing step contains at least one selected from the group consisting of ester compounds, ketone compounds and alcohol compounds. Pattern formation method.

According to the present invention, it is possible to obtain a resist material capable of forming a highly sensitive resist film.

FIG. 1 is a cross-sectional view illustrating the configuration of a substrate and a resist film.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments and specific examples, but the present invention is not limited to such embodiments. In addition, the numerical range represented by using "-" in this specification means the range including the numerical values before and after "-" as the lower limit value and the upper limit value.

(Resist material)
The present invention relates to a resist material containing a polymer containing a unit derived from a structure represented by the following general formula (101) and a unit derived from a structure represented by the following general formula (104).

In the general formula (101), R ¹ may independently have a hydrogen atom, an alkyl group which may have a substituent, an acyl group which may have a substituent, and a substituent. It represents an allyl group, an alkoxy group which may have a substituent or an alkylsilyl group which may have a substituent, and a plurality of R ^1s may be the same or different. R ¹¹ represents an alkyl group which may have a hydrogen atom or a substituent. R ² represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ¹ represents a single bond or a linking group.

Further, in the general formula (104), X ³ represents an alkyl halide group, R ⁵ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ⁴ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom or an alkyl halide group. Represents a single bond or linking group.

The resist material of the present invention can form a highly sensitive resist film by containing a polymer containing a unit derived from the above structure. Specifically, even when the irradiation amount (dose amount) of the electromagnetic beam per unit area to irradiate the resist film formed from the resist material is small, a pattern having a desired shape can be formed. For example, in the resist material of the present embodiment, for example, when the dose amount at the time of electron beam irradiation is 160 μC / cm ² or less, or when the dose amount is 60 μC / cm ² or less or 45 μC / cm ² or less. Even if there is, it is possible to form a finely shaped pattern. In the highly sensitive resist film, the irradiation intensity of the electron beam can be weakened, and the irradiation time can be shortened, so that the efficiency of the patterning process can be improved.

Further, the resist material of the present embodiment can form a resist film capable of high-definition patterning by containing a polymer containing a unit derived from the above structure. That is, the resist film formed from the resist material of the present embodiment has a high resolution. For example, even in a line-and-space line pattern with a narrow line width, it can be evaluated that the resolution of the resist film is high when the line is linear and there is no residue derived from the resist film in the space portion. That is, when the resolution of the resist film is high, it is possible to form a pattern having a high definition and a desired shape.

The content of the polymer is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, based on the total mass of the resist material. The polymer content is preferably 40% by mass or less, more preferably 30% by mass or less, based on the total amount of the resist material.

The resist film formed from the resist material of the present embodiment is a film (protective film) provided on the substrate for forming a pattern on a substrate such as a silicon wafer. The resist film may be a film provided so as to be in direct contact with the substrate, or may be a film laminated on the substrate via another layer. The resist film is processed into a pattern shape to be formed on the substrate, and the portion left as the pattern shape becomes a protective film in the subsequent etching process. After the pattern is formed on the substrate, the resist film (protective film) may be removed from the substrate. As described above, the resist film is used, for example, in a step of forming a pattern on a substrate.

The resist material of the present embodiment is preferably a main chain cutting type positive resist material. The main chain of the polymer contained in the resist material is cut by irradiation with electromagnetic rays, and only the exposed portion is dissolved in the developing solution. This makes it possible to form a higher-definition pattern.

<Polymer>
The resist material of the present embodiment contains a polymer containing a unit derived from the structure represented by the following general formula (101) and a unit derived from the structure represented by the following general formula (104). That is, the polymer preferably contains at least a unit derived from a sugar derivative and a unit having an alkyl halide group. In the present specification, the "unit" is a repeating unit (monomer unit) constituting the main chain of the polymer. However, the side chain of the unit derived from one sugar derivative may further contain a unit derived from the sugar derivative, and in this case, the repeating unit (monomer unit) constituting the polymer of the side chain is also referred to in the present specification. Corresponds to "unit".

In the general formula (101), R ¹ may independently have a hydrogen atom, an alkyl group which may have a substituent, an acyl group which may have a substituent, and a substituent. It represents an allyl group, an alkoxy group which may have a substituent or an alkylsilyl group which may have a substituent, and a plurality of R ^1s may be the same or different. R ¹¹ represents an alkyl group which may have a hydrogen atom or a substituent. R ² represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ¹ represents a single bond or a linking group.

Further, in the general formula (104), X ³ represents an alkyl halide group, R ⁵ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ⁴ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom or an alkyl halide group. Represents a single bond or linking group.

In the general formula (101), R ¹ independently has a hydrogen atom, an alkyl group which may have a substituent, an acyl group which may have a substituent, and an allyl which may have a substituent. Represents a group, an alkoxy group which may have a substituent or an alkylsilyl group which may have a substituent. Here, the alkyl group which may have a substituent includes a sugar derivative group, and R ¹ may be a unit derived from a linear or branched sugar derivative. The unit derived from the linear or branched sugar derivative is preferably a sugar derivative having the same structure as the sugar derivative to be bound. When R ¹ is a unit derived from a linear or branched sugar derivative, the number of linked sugar derivative groups (average degree of polymerization of the sugar derivative) is preferably 20 or less, and preferably 10 or less. More preferred.

Among them, it is preferable that R ¹ is an independently hydrogen atom and an alkyl group which may have a substituent or an acyl group which may have a substituent, and R ¹ is an independent hydrogen atom or a substituent. It is more preferably an acyl group which may have a group, and even more preferably an acyl group which may have a substituent. When R ¹ is an acyl group which may have a substituent, the sensitivity of the resist material can be increased more effectively.

When R ¹ is an alkyl group or an acyl group, the carbon number thereof can be appropriately selected depending on the intended purpose. For example, the number of carbon atoms is preferably 1 or more, preferably 200 or less, more preferably 100 or less, further preferably 20 or less, and particularly preferably 4 or less.

Specific examples of R ¹ include, for example, an acetyl group, a propanoyl group, a butyl group, an isobutylyl group, a valeryl group, an isovaleryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, a chloroacetyl group, a trichloroacetyl group, and a trifluoroacetyl group. Acetyl groups such as cyclopentanecarbonyl group, cyclohexanecarbonyl group, benzoyl group, methoxybenzoyl group, triflumethoxybenzoyl group, chlorobenzoyl group; methyl group, ethyl group, n-propyl group, n-butyl group, i-butyl group, Examples thereof include an alkyl group such as a t-butyl group. Among these, R ¹ is preferably a methyl group, an ethyl group, an acetyl group, a trifluoroacetyl group, a propanoyl group, an n-butyryl group, an isobutyryl group, a benzoyl group or a trimethylsilyl group, preferably an acetyl group, a propanoyl group or a group. It is particularly preferably a trifluoroacetyl group.

In the general formula (101), R ¹¹ represents an alkyl group which may have a hydrogen atom or a substituent. When R ¹¹ represents an alkyl group which may have a substituent, examples of the alkyl group include a methyl group, an ethyl group, a propyl group and the like. Of these, the alkyl group is preferably a methyl group, and such an alkyl group preferably has a substituent. Examples of the substituent having an alkyl group include a hydroxyl group, an acyl group, an allyl group, an alkoxy group and the like, and the substituent is preferably a hydroxyl group or an acyl group. More specifically, when R ¹¹ represents an alkyl group which may have a substituent, R ¹¹ is preferably −CH ₂ OR ¹ , and R ¹ may be the above-mentioned group. can. However, in the general formula (101), it is particularly preferable that R ¹¹ is a hydrogen atom. By using R ¹¹ as a hydrogen atom, it becomes easy to form a finer pattern structure.

In the general formula (101), R ² represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group. Among them, R ² is preferably a hydrogen atom, an alkyl group having 1 or more and 3 or less carbon atoms, a fluorine atom, a chlorine atom or a bromine atom, and particularly preferably a fluorine atom, a chlorine atom or a bromine atom. By introducing a fluorine atom, a chlorine atom or a bromine atom into R ² , the resist film formed can be made more sensitive.

In general formula (101), Y ¹ independently represents a single bond or a linking group. When Y ¹ is a linking group, examples of Y ¹ include a linking group that does not contain a sugar unit, and includes, for example, an alkylene group, a phenylene group, —O—, —C (= O) O—, and the like. The group is mentioned. Y ¹ may be a linking group in which these groups are combined. Above all, Y ¹ is preferably a linking group represented by the following structural formula.

In the above structural formula, the * mark represents the binding site with the main chain side, and the * mark represents the binding site with the sugar unit of the side chain.

In the above general formula (101), the structure of the sugar derivative is described as a cyclic structure, but the structure of the sugar derivative is not only a cyclic structure but also an open structure (chain structure) called aldose or ketose. May be.

Since the resist material of the present embodiment contains the structure of the sugar derivative represented by the above general formula (101), it is useful as a main chain cutting type positive resist material. Generally, in a main chain cutting type resist, it is said that radicals are generated in the polymer by the irradiated light energy to cut the main chain. However, in the conventional main chain cutting type resist, even if a radical is generated, the radical disappears thereafter, so that the efficiency of main chain cutting is low, and therefore the sensitivity is low. On the other hand, in the resist material of the present embodiment, the number of radical generation sites increases due to the presence of sugar chains having many CO-bonds, and the frequency of radical generation increases even if the light energy per unit area is low. , Main chain breakage can be further promoted. It is considered that this has improved the sensitivity of the resist material.

^In the general formula (104), X3 represents an alkyl halide group. The alkyl halide group represented by X ³ preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms. The alkyl halide group is preferably a fluoroalkyl group, a chloroalkyl group or a bromoalkyl group, more preferably a fluoroalkyl group or a chloroalkyl group, and particularly preferably a fluoroalkyl group. Examples of the halogenated alkyl group include a difluoroalkyl group, a trichloroalkyl group, a perfluoroalkyl group, a trifluoroalkyl group, a tetrafluoroalkyl group, a heptafluoroalkyl group, a hexafluoroalkyl group, and a hexachloroalkyl group. ..

In the general formula (104), R ⁵ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group. Among them, R5 is preferably a hydrogen atom, an alkyl group having 1 or more and ³ or less carbon atoms, a fluorine atom, a chlorine atom or a bromine atom, and a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms. Especially preferable.

^In the general formula (104), Y4 represents a single bond or a linking group. When Y ⁴ is a linking group, examples of Y ⁴ include a linking group that does not contain a sugar unit, and includes, for example, an alkylene group, a phenylene group, —O—, —C (= O) O—, and the like. The group is mentioned. ^Y4 may be a linking group in which these groups are combined. As Y ⁴ , the same structure as the group that Y ¹ can take in the general formula (101) can be exemplified.

The content (mol%) of the unit derived from the structure represented by the general formula (101) is preferably 0.5 mol% or more and 95 mol% or less with respect to the total mass of the polymer, and is preferably 1 mol%. It is more preferably 90 mol% or more, more preferably 2 mol% or more and 85 mol% or less, and particularly preferably 5 mol% or more and 75 mol% or less. By setting the content of the unit derived from the structure represented by the general formula (101) within the above range, the sensitivity of the resist film formed from the resist material can be more effectively increased.

The content (% by mass) of the unit derived from the structure represented by the general formula (104) is preferably 0.3 mol% or more and 40 mol% or less with respect to the total mass of the polymer, and is 0. It is more preferably 5.5 mol% or more and 30 mol% or less, further preferably 0.7 mol% or more and 20 mol% or less, and particularly preferably 1 mol% or more and 10 mol% or less. By setting the content of the unit derived from the structure represented by the general formula (104) within the above range, the sensitivity of the resist film formed from the resist material can be more effectively increased.

The content of the unit derived from the structure represented by the general formula (101) and the content of the unit derived from the structure represented by the general formula (104) are, for example, the molar composition ratio from the signal integral ratio of ¹ H-NMR. Can be asked.

一般式（１０２） The polymer contained in the resist material of the present embodiment preferably further contains a unit derived from the structure represented by the following general formula (102).

General formula (102)

In the general formula (102), X ¹ is an alkyl group which may have a substituent (excluding those containing a halogen atom in the substituent), an acyl group which may have a substituent or a substituent. Represents an allyl group which may have a group. R ³ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ² represents a single bond or a linking group.

In the general formula (102), X ¹ is an alkyl group which may have a substituent (excluding those containing a halogen atom in the substituent), an acyl group which may have a substituent or a substituent. Represents an allyl group which may have a group. Among them, X ¹ is preferably an alkyl group which may have a substituent (excluding those containing a halogen atom in the substituent), and particularly preferably an alkyl group having no substituent. preferable. The number of carbon atoms of the alkyl group is preferably 1 or more and 8 or less, more preferably 1 or more and 5 or less, and further preferably 1 or more and 3 or less. The carbon number is the number of carbons excluding the substituent. Examples of the alkyl group having a substituent include _-CH2 -OH, _-CH2 -O-methyl, _-CH2 -O-ethyl, _-CH2 -On-propyl, and _-CH2 -O. -Isopropyl, -CH ₂ -On-Butyl, -CH ₂ -O-Isobutyl, -CH ₂ -O-t-Butyl, -CH ₂ -O- (C = O) -Methyl, -CH ₂ -O -(C = O) -ethyl, -CH ₂ -O- (C = O) -propyl, -CH ₂ -O- (C = O) -isopropyl, -CH ₂ -O- (C = O) -n -Butyl, -CH ₂ -O- (C = O) -isobutyl, -CH ₂ -O- (C = O) -t-butyl, -C ₂ H ₄ -OH, -C ₂ H ₄ -O-methyl , -C ₂ H ₄ -O-ethyl, -C ₂ H ₄ -On-propyl, -C ₂ H ₄ -O-isopropyl, -C ₂ H ₄ -On-butyl, -C ₂ H ₄ -O-isobutyl, -C ₂ H ₄ --O-t-butyl, -C ₂ H ₄ --O- (C = O) -methyl, -C ₂ H ₄ -O- (C = O) -ethyl,- C ₂ H ₄ -O- (C = O) -n-propyl, -C ₂ H ₄ -O- (C = O) -isopropyl, -C ₂ H ₄ -O- (C = O) -n-butyl , -C ₂ H ₄ -O- (C = O) -isobutyl, -C ₂ H ₄ -O- (C = O) -t-butyl, -C ₂ H ₄ -O- (C = O) -CH _2- (C = O) -methyl and the like can be mentioned. Further, the alkyl group having a substituent may be a cycloalkyl group.

In the general formula (102), R ³ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group. Among them, R ³ is preferably a hydrogen atom, an alkyl group having 1 or more and 3 or less carbon atoms, a fluorine atom, a chlorine atom or a bromine atom, and particularly preferably a fluorine atom, a chlorine atom or a bromine atom. By introducing a fluorine atom, a chlorine atom or a bromine atom into R ³ , the resist film formed can be made more sensitive. When the polymer contained in the resist material further contains a unit derived from the structure represented by the general formula (102), at least one of R ² in the general formula (101) and R ³ in the general formula (102) It is preferably a fluorine atom, a chlorine atom or a bromine atom. Both R ² in the general formula (101) and R ³ in the general formula (102) may be a fluorine atom, a chlorine atom or a bromine atom.

In the general formula (102), Y ² represents a single bond or a linking group. When Y ² is a linking group, examples of Y ² include a group containing an alkylene group, a phenylene group, —O—, —C (= O) O— and the like. Y ² may be a linking group in which these groups are combined. Above all, Y ² is preferably a linking group represented by the following structural formula.

In the above structural formula, the * mark represents the binding site with the main chain ^side , and the * mark represents the binding site with X1.

When the polymer contains units derived from the structure represented by the general formula (102), the content (mol%) of the units derived from the structure represented by the general formula (102) is based on the total mass of the polymer. It is preferably 0.5 mol% or more and 99 mol% or less, more preferably 3 mol% or more and 98 mol% or less, and particularly preferably 10 mol% or more and 95 mol% or less. The content rate (mol%) of the unit derived from the structure represented by the general formula (102) is the same method as the calculation of the content rate of the unit derived from the structure represented by the general formula (101) described above. Can be calculated with.

The polymer contained in the resist material of the present embodiment preferably further contains a unit derived from the structure represented by the following general formula (103). By further including the unit derived from the structure represented by the general formula (103) in the polymer, the solubility in an organic solvent can be improved.

In the general formula (103), X ² represents an aryl group which may have a substituent. ^R4 represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group ^, and Y3 represents a single bond or a linking group.

In the general formula (103), X ² represents an aryl group which may have a substituent. Above all, X ² is preferably a phenyl group.

In the general formula (103), R ⁴ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group. Among them, ^R4 is preferably a hydrogen atom, an alkyl group having 1 or more and 3 or less carbon atoms, a fluorine atom, a chlorine atom or a bromine atom, and particularly preferably a fluorine atom, a chlorine atom or a bromine atom. By introducing a fluorine atom, a chlorine atom or a bromine atom into R ⁴ , the resist film formed can be made more sensitive.

In the general formula (103), Y ³ represents a single bond or a linking group. When Y ² is a linking group, examples of Y ³ include a group containing an alkylene group, a phenylene group, —O—, —C (= O) O—, and the like. Y3 may be a linking group in which these groups ^are combined. However, it is particularly preferable that ^Y3 is a single bond.

The unit derived from the structure represented by the general formula (103) is preferably a unit derived from a styrene compound. Examples of the styrene compound include styrene, o-methylstyrene, p-methylstyrene, ethylstyrene, p-methoxystyrene, p-phenylstyrene, 2,4-dimethylstyrene, pn-octylstyrene and pn-. Decylstyrene, pn-dodecylstyrene, chlorostyrene, bromostyrene, trimethylsilylstyrene, hydroxystyrene, 3,4,5-methoxystyrene, pentamethyldisilylstyrene, t-butoxycarbonylstyrene, tetrahydropyranylstyrene, phenoxyethyl Examples thereof include styrene and t-butoxycarbonylmethylstyrene.

When the polymer contains units derived from the structure represented by the general formula (103), the content (mol%) of the units derived from the structure represented by the general formula (103) is based on the total mass of the polymer. It is preferably 0.5 mol% or more and 98 mol% or less, more preferably 2 mol% or more and 97 mol% or less, and particularly preferably 10 mol% or more and 95 mol% or less. The content rate (mass%) of the unit derived from the structure represented by the general formula (103) is the same method as the calculation of the content rate of the unit derived from the structure represented by the general formula (101) described above. Can be calculated with.

The polymer contained in the resist material of the present embodiment contains units derived from the structures represented by the above-mentioned general formulas (101) and (104), and further, the general formula (102) and / or It preferably contains a unit derived from the structure represented by (103). As described above, the polymer contained in the resist material of the present embodiment is a copolymer, and the copolymer may be a block copolymer or a random copolymer. Further, the copolymer may have a structure in which a part is a random copolymer and a part is a block copolymer. In this way, an appropriate structure can be appropriately selected depending on the intended use and required physical characteristics. However, the copolymer is preferably a random copolymer because the radical generation sites are dispersed in the polymer so that the resist has a high resolution and a fine pattern can be formed.

The weight average molecular weight (Mw) of the polymer is preferably 5000 or more, more preferably 8000 or more, and further preferably 10000 or more. The weight average molecular weight (Mw) of the polymer is preferably 2 million or less, more preferably 1.5 million or less, further preferably 1 million or less, still more preferably 700,000 or less. .. The weight average molecular weight (Mw) of the polymer is a value measured in terms of polystyrene by GPC.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the polymer is preferably 1 or more. Further, Mw / Mn is preferably 100 or less, more preferably 50 or less, further preferably 20 or less, further preferably 15 or less, and particularly preferably 10 or less. ..

The solubility of the polymer in at least one selected from PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, ethyl lactate, N-methylpyrrolidone, γ-butyrolactone and DMF is preferably 1% by mass or more. It is more preferably 2% by mass or more, particularly preferably 3% by mass or more, and even more preferably 4% by mass or more. The upper limit of the solubility of the polymer in the organic solvent is not particularly limited, but may be, for example, 40% by mass. The solubility is at least one selected from PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, ethyl lactate, N-methylpyrrolidone, γ-butyrolactone and DMF.

The method for measuring the solubility of a polymer is that when PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, ethyl lactate, N-methylpyrrolidone, γ-butyrolactone or DMF are gradually added to a predetermined amount of the polymer, the mixture is stirred and dissolved. Record the amount of organic solvent added in. A magnetic stirrer or the like may be used for stirring. Then, the solubility is calculated from the following formula.
Solubility (% by mass) = mass of polymer / (mass of polymer + mass of organic solvent) x 100

<Polymer synthesis method>
The polymer can be synthesized by a known polymerization method such as living radical polymerization, living anionic polymerization, or atom transfer radical polymerization. For example, in the case of living radical polymerization, a copolymer can be obtained by reacting with a monomer using a polymerization initiator such as AIBN (α, α'-azobisisobutyronitrile). In the case of living anionic polymerization, a polymer can be obtained by reacting butyllithium with a monomer in the presence of lithium chloride. Although a polymer synthesis example is shown in this example, the present embodiment is not limited to this, and can be appropriately synthesized by each of the above synthetic methods or a known synthetic method. For example, the method described in International Publication WO99 / 062964 or the like can be used.

Further, when synthesizing the polymer, a step of extracting from lignocellulosic derived from a woody plant or a herbaceous plant may be combined. For example, in the case of adopting a method of extracting from lignocellulosic derived from a woody plant or a herbaceous plant, the extraction method described in JP-A-2012-100546 can be used.

Xylan can be extracted, for example, by the method disclosed in Japanese Patent Application Laid-Open No. 2012-180424.

Then, when synthesizing the polymer, it is preferable to modify the OH group of the sugar portion obtained by the above extraction method by esterification or the like. For example, when an acetyl group is introduced, an acetylated sugar derivative portion can be obtained by reacting with acetic anhydride.

When synthesizing the copolymer, Macromolecules Vol. 36, No. It is also possible to synthesize with reference to 6, 2003. Specifically, each compound is put into a solvent containing DMF, water, acetonitrile and the like, and a reducing agent is added. Examples of the reducing agent include NaCNBH ₃ and the like. Then, the mixture is stirred at 30 ° C. or higher and 100 ° C. or lower for 1 day or more and 20 days or less, and a reducing agent is appropriately added as necessary. A precipitate can be obtained by adding water, and a copolymer can be obtained by vacuum drying the solid content.

Examples of the copolymer synthesis method include a synthesis method using radical polymerization, RAFT polymerization, ATRP polymerization, click reaction, and NMP polymerization, in addition to the above methods.
Radical polymerization is a polymerization reaction that occurs when an initiator is added to generate two free radicals by a thermal reaction or a photoreaction. The monomer (eg, a styrene monomer and a sugar methacrylate compound in which methacrylic acid is added to the β-1 position at the end of the xylooligosaccharide) and the initiator (for example, an azo compound such as azobisbutyronitrile (AIBN)) are heated at 150 ° C. This makes it possible to synthesize a polystyrene-polysaccharide methacrylate random copolymer.
RAFT polymerization is a radical initiation polymerization reaction accompanied by an exchange chain reaction using a thiocarbonylthio group. For example, a method can be taken in which the OH group attached to the terminal 1 position of the xylooligosaccharide is converted into a thiocarbonylthio group, and then the styrene monomer is reacted at 30 ° C. or higher and 100 ° C. or lower to synthesize a copolymer (Material Meters vol). .5, No.1 Latest Polymer Synthesis Sigma Aldrich Japan Co., Ltd.).
In ATRP polymerization, the terminal OH group of the sugar is halogenated, and the metal complex [(CuCl, CuCl ₂ , CuBr, CuBr ₂ , CuI, etc.) + TPMA (tris (2-pyridylmonomer) amino)], MeTREN (tris [2- (dimethyrene)). ) Ethyl] amine), etc.), a monomer (eg, styrene monomer), and a polymerization initiator (2,2,5-trimethyl-3- (1-phenylethoxy) -4-phenyl-3-azahexane). Allows the synthesis of sugar copolymers (eg, sugar-styrene block copolymers).
In NMP polymerization, by heating with an alkoxyamine derivative as an initiator, a reaction with a monomer molecule is caused to generate nitroxide. After that, radicals are generated by thermal dissociation, and the polymerization reaction proceeds. Such NMP polymerization is a kind of living radical polymerization reaction. A monomer (for example, a styrene monomer and a sugar methacrylate compound in which methacrylic acid is added to the β-1 position at the end of a xylooligosaccharide) is mixed, and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) is used as an initiator. Polystyrene-polysaccharide methacrylate random copolymers can be synthesized by heating at 140 ° C.
The click reaction is a 1,3-bipolar azide / alkyne cycloaddition reaction using a sugar having a propargyl group and a Cu catalyst.

<Organic solvent>
The resist material of the present embodiment may further contain an organic solvent. However, the resist material may further contain an aqueous solvent such as water or various aqueous solutions in addition to the organic solvent. Examples of the organic solvent include alcohol-based solvents, ether-based solvents, ketone-based solvents, sulfur-containing solvents, amide-based solvents, ester-based solvents, hydrocarbon-based solvents and the like. These solvents may be used alone or in combination of two or more.

Examples of the alcohol-based solvent include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, tert-butanol, n-pentanol, i-pentanol and 2-methylbutanol. , Se-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethyl Hexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, flufuryl alcohol , Phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol, etc .; ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanol Diol, 2-methyl-2,4-pentandiol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene Glycols, 1H, 1H-trifluoroethanol, 1H, 1H-pentafluoropropanol, 6- (perfluoroethyl) hexanol, etc .; can be mentioned.

Further, as the polyhydric alcohol partially ether-based solvent, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2. -Ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, diethylene glycol dimethyl ether, diethylene glycol ethylmethyl ether, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene Examples thereof include glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and dipropylene glycol monopropyl ether.

Examples of the ether solvent include diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, tetrahydrofuran (THF) and the like.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, methyl-i-pentyl ketone, and ethyl-. n-butyl ketone, methyl-n-hexyl ketone, di-i-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentandione, acetonylacetone, acetophenone , Full full, etc.

Examples of the sulfur-containing solvent include dimethyl sulfoxide and the like.

Examples of the amide solvent include N, N'-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide. , N-Methylpropionamide, N-methylpyrrolidone and the like.

Examples of the ester solvent include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate and acetic acid. sec-butyl, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, acet Methyl acetate, ethyl acetoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl acetate ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene acetate Glycol monoethyl ether, propylene glycol monopropyl ether acetate, propylene glycol monobutyl acetate ether, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl acetate ether, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-propionic acid Butyl, i-amyl propionate, methyl 3-methoxypropionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate , Diethyl phthalate and the like.

As the hydrocarbon solvent, for example, as an aliphatic hydrocarbon solvent, n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane, i-octane, cyclohexane, methylcyclohexane, etc .; as aromatic hydrocarbon solvents, benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, i-propylbenzene, diethylbenzene, etc. Examples thereof include i-butylbenzene, triethylbenzene, di-i-propylbenzene, n-amylnaphthalene and anisole.

Among these, the organic solvents are propylene glycol monomethyl ether acetate (PGMEA), N, N-dimethylformamide (DMF), propylene glycol monomethyl ether (PGME), anisole, ethanol, methanol, acetone, methyl ethyl ketone, hexane, and tetrahydrofuran (THF). ), Dimethylsulfoxide (DMSO), 1H, 1H-trifluoroethanol, 1H, 1H-pentafluoropropanol, 6- (perfluoroethyl) hexanol, ethyl acetate, propyl acetate, butyl acetate, cyclohexanone, furfural, N-methylpyrrolidone. Alternatively, it is more preferably γ-butylolactone, more preferably PGMEA, PGME, THF, butyl acetate, anisole, cyclohexanone, N-methylpyrrolidone, γ-butyrolactone or DMF, and more preferably anisole, PGME or PGMEA. More preferred. These solvents may be used alone or in combination of two or more.

The content of the organic solvent is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, based on the total mass of the resist material. The content of the organic solvent is preferably 99.9% by mass or less, more preferably 99% by mass or less. By setting the content of the organic solvent within the above range, the coatability of the resist material can be improved.

<Arbitrary ingredient>
The resist material of this embodiment may contain an optional component as described later.

<< Monomer component >>
The resist material of the present embodiment may further contain a monomer component constituting the polymer in addition to the polymer. Examples of the monomer component include the above-mentioned compounds represented by the general formula (101) or the general formula (104), and the compounds represented by the general formula (102) or (103).

<< Crosslinkable compound >>
The resist material of this embodiment may further contain a crosslinkable compound. By this cross-linking reaction, the formed resist film becomes strong and the etching resistance can be enhanced. Further, when a crosslinkable compound is added, the crosslinking reaction of the polymer in the exposed portion can be promoted and insolubilized by irradiating with an electromagnetic wave. In this case, the resist film (resist material) in the unexposed portion is removed by treating with an appropriate developer.

The crosslinkable compound is not particularly limited, but a crosslinkable compound having at least two crosslink-forming substituents is preferably used. A compound having two or more, for example, 2 to 6 crosslinkable substituents selected from an isocyanate group, an epoxy group, a hydroxymethylamino group, and an alkoxymethylamino group can be used as the crosslinkable compound. .. As the crosslinkable compound, only one kind of compound can be used, or two or more kinds of compounds can be used in combination.

These crosslinkable compounds can undergo a crosslink reaction by self-condensation. It can also cause a cross-linking reaction with the structural units contained in the polymer.

<< Catalyst >>
The resist material contains p-toluene sulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonic acid, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, ammonium dodecylbenzenesulfonic acid, as catalysts for promoting the cross-linking reaction. Acid compounds such as hydroxybenzoic acid can be added. In addition, as a catalyst, 2,4,4,6-tetrabromocyclohexadienone, benzointosylate, 2-nitrobenzyltosylate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate , Phenyl-bis (trichloromethyl) -s-triazine, N-hydroxysuccinimide trifluoromethanesulfonate and other acid generators can be added.

<< Light antireflection agent >>
The resist material of the present embodiment may further contain an antireflection agent. Examples of the light antireflection agent include compounds having an absorbance. Examples of the absorbent compound include those having a high absorption ability for light in the photosensitive characteristic wavelength region of the photosensitive component in the photoresist provided on the light reflection antireflection film, and examples thereof include benzophenone compounds and the like. Examples thereof include benzotriazole compounds, azo compounds, naphthalene compounds, anthracene compounds, anthracinone compounds, and triazine compounds. Examples of the polymer include polyester, polyimide, polystyrene, novolak resin, polyacetal, acrylic polymer and the like. Examples of the polymer having an absorptive group linked by a chemical bond include a polymer having an absorptive aromatic ring structure such as an anthracene ring, naphthalene ring, benzene ring, quinoline ring, quinoxaline ring, and thiazole ring.

<< Other ingredients >>
The resist material may further contain an ionic liquid, a surfactant and the like. By containing an ionic liquid in the resist material, the compatibility between the polymer and the organic solvent can be enhanced.
By containing a surfactant in the resist material, the applicability of the resist material to the substrate can be improved. Preferred surfactants include nonionic surfactants, fluorine-based surfactants and silicon-based surfactants.
In addition, any known material such as a rheology adjuster, an adhesion aid, an acid generator, a sensitizer, and a quencher may be included in the resist material.

The content of the optional component as described above is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total mass of the resist material.

(Resist film)
The present invention may relate to a resist film formed from the resist material described above. The resist film is used when forming a pattern on a substrate or the like, and is a film that can function as a protective film when an etching process is applied to the substrate. The resist film includes a layered film before forming a pattern and an intermittent film after forming a pattern.

FIG. 1A shows a laminate in which a resist film 40 is formed on a substrate 10. Although not shown, another layer may be provided between the substrate 10 and the resist film 40.

As shown in FIG. 1 (b), at least a part of the resist film 40 is removed so as to have a pattern shape desired to be formed on the substrate 10. For example, the resist film 40 can be exposed and developed to form a pattern shape as shown in FIG. 1 (b).

In the exposure step, an electromagnetic wave is applied to the resist film 40 through a mask on which a circuit pattern is drawn, and the resist film in the portion exposed to the light is altered to transfer the pattern. At this time, it is preferable that the main chain of the polymer contained in the resist film is cut at the portion exposed to light. As a result, the molecular weight of the polymer is reduced, the exposed portion can be dissolved and removed with a developing solution, and an intermittent portion of the resist film is formed. The substrate 10 is exposed at the intermittent portion of the resist film thus formed. For the exposed substrate 10, chlorine gas, boron trichloride, methane tetrafluoride gas, methane trifluoride gas, ethane hexafluoride gas, propane octafluoride gas, butane octafluoride gas, sulfur hexafluoride gas, argon gas , Oxygen gas, helium gas, etc. are used to form a pattern by performing reactive ion etching or the like such as inductively coupled plasma, and a pattern as shown in FIG. 1C is formed on the substrate 10. Further, in the exposure step, exposure without using a mask such as a maskless exposure machine or an electron beam drawing apparatus can be performed. In that case, a latent image can be drawn directly on the resist by irradiating the resist film 40 with light energy using a fine beam.

The film thickness of the resist film can be appropriately adjusted depending on the application, but for example, it is preferably 1 nm or more and 20000 nm or less, more preferably 1 nm or more and 10000 nm or less, and further preferably 1 nm or more and 5000 nm or less. It is particularly preferable that the thickness is 1 nm or more and 3000 nm or less.

The resist film may be a film for introducing a metal, or may be a film into which a metal has been introduced. The resist film may contain a metal. In this case, the metal content of the resist film is preferably 3 at% or more, more preferably 5 at% or more, further preferably 7 at% or more, and particularly preferably 10 at% or more. The metal content can be calculated, for example, by the following method. EDX analysis (energy dispersive X-ray analysis) was performed on the resist film after metal introduction using an electron microscope JSM7800F (manufactured by JEOL Ltd.) to calculate the ratio of metal components (metal content), which was used as the metal content. And.

(Pattern formation method)
The present invention also relates to a pattern forming method using the resist material described above. Specifically, the pattern forming method preferably includes a step of applying the above-mentioned resist material on a substrate to form a resist film, an exposure step, and a developing step.

Examples of the substrate used in the pattern forming method include substrates such as glass, silicon, SiN, GaN, AlN, SiO ₂ , quartz, and sapphire. Further, a substrate made of an organic material such as PET, PE, PEO, PS, cycloolefin polymer, polylactic acid, and cellulose nanofiber may be used.

Before applying the resist material to the substrate, it is preferable to provide a step of cleaning the substrate. By cleaning the surface of the substrate, the applicability of the resist material is improved. As the cleaning treatment method, a conventionally known method can be used, and examples thereof include oxygen plasma treatment, ozone oxidation treatment, acid-alkali treatment, and chemical modification treatment.

The method for applying the resist material is not particularly limited, but for example, the resist material can be applied onto the substrate by a known method such as a spin coating method. Further, after the resist material is applied, the resist material may be cured by heating to form a resist film. The temperature at which the coating film is heated is not particularly limited, but is preferably 60 or more and 550 ° C. or less. Further, the heat treatment is preferably a heat treatment in the atmosphere and at a relatively low temperature.

The substrate and the resist film are preferably laminated so that adjacent layers are in direct contact with each other in this order, but another layer may be provided between the layers. For example, an anchor layer or an antireflection film may be provided between the substrate and the resist film. The anchor layer is a layer that controls the wettability of the substrate and enhances the adhesion between the substrate and the resist film. The antireflection film is a layer that absorbs the electromagnetic waves used. Further, a plurality of layers made of different materials may be sandwiched between the substrate and the resist film. These materials are not particularly specified, but include inorganic materials such as SiO ₂ , SiN, Al ₂ O ₃ , AlN, GaN, GaAs, W, Cr, Ru, TaN, SOG, and amorphous carbon. Examples include commercially available organic materials such as SOCs and adhesives. When the light antireflection film is provided between the substrate and the resist film, the composition for the light antireflection film used for forming the light antireflection film is not particularly limited, and can be selected from those commonly used in the lithography process. It can be arbitrarily selected and used.

When forming a pattern on a resist film, a step of exposing through a mask on which a circuit pattern is drawn (exposure step) or a step of exposing using fine electromagnetic waves without using a mask (exposure step) is performed. It is preferable to include it. As the electromagnetic waves used for exposure, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm) and F2 excimer laser (wavelength 157 nm), electron beam, EUV (extreme ultraviolet rays, wavelength 13.5 nm or less), etc. are used. can do. Since the exposure draws a fine pattern, it is preferable to use an electron beam or EUV. After the exposure, if necessary, post-exposure heating can be performed. The post-exposure heating is preferably performed under the conditions of a heating temperature of 70 ° C. to 150 ° C. and a heating time of 0.3 to 10 minutes.

In the exposure process, by irradiating with electromagnetic waves, the resist film in the portion exposed to the light is altered and the mask pattern is transferred. At this time, it is preferable that the main chain of the polymer contained in the resist film is cut at the portion exposed to light. In the portion where the main chain of the polymer is cut, the resist film (resist material) in the exposed portion is removed in the developing step of the subsequent step.

When the resist film is irradiated with electromagnetic waves in the exposure step, the wavelength of the electromagnetic waves is preferably 15 nm or less, and the wavelength of the electromagnetic waves is preferably 0.0001 nm or more. By irradiating an electromagnetic wave having a wavelength of 15 nm or less in the exposure process, a fine pattern can be formed with high accuracy.

When the resist material contains a polymer having a crosslinkable group or a crosslinkable compound is added, the resist material is irradiated with light energy to promote the crosslinking reaction of the polymer in the exposed portion and insolubilize it. You can also let it. In this case, the resist film (resist material) in the unexposed portion is removed by treating with an appropriate developer.

The developer used in the developing step is not particularly limited, but a known developer can be used. For example, esters such as aromatics such as xylene, toluene and anisole, pentyl acetate, hexyl acetate, heptyl acetate, octyl acetate, ethyl acetate, propyl acetate, n-butyl acetate, ethyl lactate, propyl lactate, butyl lactate, γ butyrolactone and the like. , Ethanol, alcohols such as isopropanol, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, ketone such as cyclohexanone, ethers such as diethylene glycol dimethyl ether, organic acids such as anhydrous acetic acid and acetic acid, and alkalis such as potassium hydroxide and sodium hydroxide. Examples include an aqueous solution of a metal hydroxide, an aqueous solution of quaternary ammonium hydroxide such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline, and an alkaline aqueous solution such as an amine aqueous solution such as ethanolamine, propylamine, and ethylenediamine. can. As the developer, these can be used alone or in combination of two or more. Further, a surfactant or the like can be added to these developers. The developing conditions are appropriately selected from a temperature of −70 to 50 ° C. and a time of 10 to 300 seconds.

Above all, the developer used in the developing step preferably contains at least one selected from the group consisting of ester compounds, ketone compounds and alcohol compounds. By using such a developer, high-sensitivity and high-definition patterning becomes easy. In addition, 2 or more kinds of the above-mentioned compounds may be used in combination in a developer. For example, when the above-mentioned compounds are mixed, the developing solution includes a mixed solution of two or more ester compounds such as butyl acetate, a mixed solution of an ester compound and an alcohol compound such as isopropyl alcohol, and an ester compound and cyclohexanone. Mixture of ketone compounds such as, ester compound and ether compound such as diethylene glycol dimethyl ether, mixture of two or more ketone compounds, mixture of ketone compound and alcohol compound, ketone compound and ether A mixed solution of a system compound, a mixed solution of two or more kinds of alcohol-based compounds, a mixed solution of an alcohol-based compound and an organic acid such as anhydrous acetic acid, and a mixed solution of an alcohol-based compound and an amine-based compound such as tetramethylammonium hydroxide are used. be able to.

Further, a rinsing step using a rinsing liquid may be provided after the developing step. The rinsing solution is not particularly limited, but a known rinsing solution can be used. For example, xylene, butyl acetate, ethanol, isopropyl alcohol, methyl isobutyl ketone, pure water and the like can be used. As the rinsing solution, these can be used alone or in combination of two or more. Further, a surfactant or the like may be added to these rinse liquids for use. The conditions of the rinsing step are appropriately selected from a temperature of −70 to 50 ° C. and a time of 10 to 100 seconds.

The pattern forming method of the present invention may further include a metal introduction step before the developing step. That is, the pattern forming method of the present invention may further include a metal introduction step between the step of forming the resist film and the exposure step, or after the developing step. In this case, examples of the metal introduction step include a step of introducing the metal into the resist membrane, such as the SIS method (Sequential Infiltration Synthesis). The metals to be introduced include Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, etc. Sr, Y, Zr, Nb, Mo, Ru, Pd, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Examples thereof include Tl, Pb, Bi, Po, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. Such a process can be performed, for example, by the method described in General of Photopolymer Science and Technology Volume 29, Number 5 (2016) 653-657. Further, in the step of introducing the metal, a method of using a metal complex gas, a method of applying a solution containing the metal, or a method of introducing the metal into the resist by an ion implant method can be adopted.

The pattern forming method of the present embodiment is a method of forming a pattern on a resist film formed from a resist material, but further includes a step of processing a semiconductor substrate or the like using the pattern formed on the resist film as a protective film. It may be. Such a process is called an etching process. In this case, an etching process is provided as a post-process of the developing process.

Known methods for processing a semiconductor substrate in the etching step include, for example, reactive ion etching (RIE) such as chemical dry etching, chemical wet etching (wet development), spatter etching, and physical etching such as ion beam etching. The method is mentioned. Processing of semiconductor substrates includes, for example, tetrafluoromethane, perfluorocyclobutane ( _C4 F ₈ ), perfluoropropane (C ₃ F ₈ ), trifluoromethane, carbon monoxide, argon, oxygen, nitrogen, chlorine, and hexafluoride. It is preferably performed by dry etching using a gas such as sulfur, difluoromethane, nitrogen trifluoride and chlorine trifluoride.

Hereinafter, the features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limiting by the specific examples shown below. Hereinafter, n, m, l, and s in the structural formulas in the examples are the number of repetitions of each structural unit in the polymer.

[Example 1: Synthesis of copolymer 1]
(Synthesis of Acetyl Sugar Methacrylate 1)
20 g of xylose was added to a mixed solution of 250 g of acetic anhydride (manufactured by Wako Pure Chemical Industries, Ltd.) and 320 g of acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), and the mixture was stirred at 30 ° C. for 2 hours. Approximately 5 times the amount of cold water of the solution was slowly added with stirring, and after stirring for 2 hours, the mixture was allowed to stand overnight to precipitate crystals. In a flask, add 1.2 g of ethylenediamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 0.14 g of acetic acid to 400 mL of tetrahydrofuran (THF, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and bring the temperature to 0 ° C., and add 10 g of the precipitated crystals. The mixture was stirred for 4 hours. This was poured into 1 L of cold water and extracted twice with dichloromethane (manufactured by Wako Pure Chemical Industries, Ltd.). 20 g of this extract, 300 mL of dichloromethane and 4.8 g of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a flask and cooled to −30 ° C. 2.8 g of methacryl chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred for 2 hours. This was poured into 300 mL of cold water, extracted twice with dichloromethane, and the solvent was concentrated to obtain 16.1 g of acetyl sugar methacrylate 1. The structure of the obtained acetyl sugar methacrylate 1 is as follows.

(Synthesis of Acetyl Sugar Methacrylate 1-Trifluoroethyl Methacrylate Random Copolymer)
After 19.5 g of acetyl sugar methacrylate and 0.5 g of 2,2,2-trifluoroethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) are placed in a flask, 100 g of THF is used as a solvent and azobisisobutyronitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) is used as a polymerization initiator. 0.8 g (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, the flask was sealed and replaced with nitrogen. The temperature was raised to 78 ° C. under a nitrogen atmosphere, and the mixture was stirred for 6 hours. Then, the temperature was returned to room temperature, and the flask was placed under the atmosphere. 300 g of methanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise to the obtained solution to precipitate the polymer. Then, the solution containing the precipitated polymer was suction-filtered to obtain 11 g of a white copolymer. The structure of each structural unit of the obtained copolymer 1 is as follows.

[Example 2: Synthesis of copolymer 2]
(Synthesis of Acetyl Sugar Methacrylate 1-Methyl Chloroacrylate-Trifluoroethyl Methacrylate Random Copolymer)
After putting 14.7 g of acetyl sugar methacrylate 1, 4.6 g of methyl 2-chloroacrylate (manufactured by Tokyo Kasei Co., Ltd.) and 0.7 g of 2,2,2-trifluoroethyl methacrylate in a flask, 100 g of THF as a solvent was used to initiate polymerization. After adding 0.8 g of azobisisobutyronitrile as an agent, the flask was sealed and replaced with nitrogen. The temperature was raised to 78 ° C. under a nitrogen atmosphere, and the mixture was stirred for 6 hours. Then, the temperature was returned to room temperature, the flask was placed under the atmosphere, and 300 g of methanol was added dropwise to the obtained solution to precipitate the polymer. Then, the solution containing the precipitated polymer was suction-filtered to obtain 12.1 g of the white copolymer 2. The structure of each structural unit of the obtained copolymer 2 is as follows.

[Example 3: Synthesis of copolymer 3]
(Synthesis of Acetyl Sugar Methacrylate 1-Methyl Methacrylate-Styrene-Trifluoroethyl Methacrylate Random Copolymer)
11.6 g of acetyl sugar methacrylate, 3.4 g of methyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 4.2 g of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.9 g of 2,2,2-trifluoroethyl methacrylate in a flask. After the addition, 100 g of THF as a solvent and 0.8 g of azobisisobutyronitrile as a polymerization initiator were placed in a flask, and the flask was sealed and replaced with nitrogen. The temperature was raised to 78 ° C. under a nitrogen atmosphere, and the mixture was stirred for 6 hours. Then, the temperature was returned to room temperature, the flask was placed under the atmosphere, and 310 g of methanol was added dropwise to the obtained solution to precipitate the polymer. Then, the solution containing the precipitated polymer was suction-filtered to obtain 10.2 g of a white copolymer 3. The structure of each structural unit of the obtained copolymer 3 is as follows.

[Example 4: Synthesis of copolymer 4]
(Synthesis of acetyl sugar chloroacrylate)
In the synthesis of acetyl sugar methacrylate 1, methacryl chloride was changed to 2-chloroacrylic acid chloride (manufactured by 1Click Chemistry Stock Products) and synthesized to obtain 20 g of acetyl sugar chloroacrylate. The structure of the obtained acetyl sugar chloroacrylate is as follows.

(Synthesis of acetyl sugar chloroacrylate-methyl chloroacrylate-methylstyrene-trifluoroethyl methacrylate random copolymer)
In the synthesis of copolymer 3, 11.6 g of acetyl sugar methacrylate 1 was changed to 9.8 g of acetyl sugar chloroacrylate, 3.4 g of methyl methacrylate was changed to 3.9 g of methyl 2-chloroacrylate, and styrene 4. The same method was used except that 2 g was changed to 4.6 g of α-methylstyrene (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and the amount of 2,2,2-trifluoroethyl methacrylate added was changed from 0.9 g to 1.8 g. 49.7 g of the copolymer was obtained. The structure of each structural unit of the obtained copolymer 4 is as follows.

[Example 5: Synthesis of copolymer 5]
(Synthesis of propyl sugar methacrylate)
In the synthesis of acetyl sugar methacrylate 1, the mixed solution of 250 g of acetic anhydride and 320 g of acetic acid was changed to 300 g of propionic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 400 g of propionic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). , 22.1 g of propyl sugar methacrylate was obtained. The structure of the obtained propyl sugar methacrylate is as follows.

(Synthesis of propyl sugar methacrylate-methyl chloroacrylate-methyl styrene-trifluoroethyl methacrylate random copolymer)
In the synthesis of the copolymer 3, 11.6 g of acetyl sugar methacrylate 1 was changed to 8.1 g of propyl sugar methacrylate, 3.4 g of methyl methacrylate was changed to 2.5 g of methyl 2-chloroacrylate, and 4.2 g of styrene was further changed. Was changed to 3.6 g of α-methylstyrene, and 10.0 g of the copolymer 5 was obtained by the same method except that the amount of 2,2,2-trifluoroethyl methacrylate changed from 0.9 g to 6.2 g. rice field. The structure of each structural unit of the obtained copolymer 5 is as follows.

[Example 6: Synthesis of copolymer 6]
(Synthesis of trifluoroacetyl sugar methacrylate)
In the synthesis of acetyl sugar methacrylate 1, a mixed solution of 250 g of acetic anhydride and 320 g of acetic acid was changed to 400 g of trifluoroacetic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 500 g of trifluoroacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.). , 20.0 g of trifluoroacetylsaccharide methacrylate was obtained. The structure of the obtained trifluoroacetyl sugar methacrylate is as follows.

(Synthesis of trifluoroacetyl sugar methacrylate-methyl chloroacrylate-methyl styrene-trifluoroethyl methacrylate random copolymer)
In the synthesis of the copolymer 3, 11.6 g of acetyl sugar methacrylate 1 was changed to 11.9 g of trifluoroacetyl sugar methacrylate, and 3.4 g of methyl methacrylate was changed to 3.4 g of methyl 2-chloroacrylate. Further, the same method was used except that 4.2 g of styrene was changed to 4.0 g of α-methylstyrene and the amount of 2,2,2-trifluoroethyl methacrylate added was changed from 0.9 g to 0.8 g. The copolymer 6 was obtained in an amount of 13.0 g. The structure of each structural unit of the obtained copolymer 6 is as follows.

[Example 7: Synthesis of copolymer 7]
(Synthesis of sugar methacrylate)
33 g of xylose was dissolved in 150 mL of water, 28.5 g of ammonium hydrogen carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) was added 4 times every 24 hours, and the mixture was stirred at 37 ° C. for 96 hours. Then, 200 mL of distilled water was added, the water was distilled off until it became 20 mL, 150 mL of water was added, and the mixture was concentrated to 10 mL. This was repeated until the ammonia odor disappeared, and after freeze-drying, a white solid was obtained. Dissolve this substance in 50 mL of a ^1x10-3M KOH (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) aqueous solution, add 10.4 g of 2-isocyanate ethyl methacrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and keep the temperature at 3 ° C. The mixture was vigorously stirred for 12 hours. After removing the precipitated white solid, the filtrate was washed 4 times with 50 mL of diethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) and freeze-dried. Then, the obtained white solid was dissolved in a mixed solution of 2 mL of water and 10 mL of methanol, and the mixture was dropped into a mixed solution of 200 mL of acetone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and cooled. Then, it was filtered through a filter and dried under reduced pressure to obtain 25 g of sugar methacrylate. The structure of sugar methacrylate is as follows.

(Synthesis of sugar methacrylate-methyl chloroacrylate-methyl styrene-trifluoroethyl methacrylate random copolymer)
In the synthesis of copolymer 3, 11.6 g of acetyl sugar methacrylate 1 was changed to 14.2 g of sugar methacrylate, 3.4 g of methyl methacrylate was changed to 2.2 g of methyl 2-chloroacrylate, and 4.2 g of styrene was further changed. Copolymer 7 11.3 g was obtained by the same method except that the amount of α-methylstyrene was changed to 2.8 g and the amount of 2,2,2-trifluoroethyl methacrylate was changed from 0.9 g to 0.8 g. .. The structure of each structural unit of the obtained copolymer 7 is as follows.

[Example 8: Synthesis of copolymer 8]
(Synthesis of Acetylxylooligosaccharide Methacrylate)
In the synthesis of acetyl sugar methacrylate 1, 20 g of xylose was changed to 55 g of xylooligosaccharide (average sugar chain length 3), and the same method was used for synthesis to obtain 30.0 g of acetylxylooligosaccharide methacrylate. The structure of the obtained acetylxylooligosaccharide methacrylate is as follows.

(Synthesis of Acetyl Xylooligosaccharide Methacrylate-Methyl Chloroacrylate-Methyl Styrene-Bromoethyl Acrylate Random Copolymer)
In the synthesis of the copolymer 3, 11.6 g of acetyl sugar methacrylate 1 was changed to 14.6 g of acetyl xylooligosaccharide methacrylate, 3.4 g of methyl methacrylate was changed to 2.3 g of methyl 2-chloroacrylate, and styrene 4. The same method was used except that 2 g was changed to 2.6 g of α-methylstyrene and 0.9 g of 2,2,2-trifluoroethyl methacrylate was changed to 0.6 g of 2-bromoethyl acrylate (manufactured by Alfa Aesar). 88.1 g of the copolymer was obtained. The structure of each structural unit of the obtained copolymer 8 is as follows.

[Example 9: Synthesis of copolymer 9]
(Synthesis of Acetyl Sugar Methacrylate 2)
120 g of acetic anhydride was added to 10 g of sugar methacrylate, and the mixture was stirred for 2 hours. Then, the reaction was stopped with a 33% by mass magnesium acetate solution (manufactured by Wako Pure Chemical Industries, Ltd.), and pure water was added to precipitate crystals to obtain 211 g of acetyl sugar methacrylate. The structure of the obtained acetyl sugar methacrylate 2 is as follows.

(Synthesis of Acetyl Sugar Methacrylate 2-Chloroacrylate Methyl-Methylstyrene-2,2,3,3,3-Pentafluoropropyl Methrate Random Copolymer)
In the synthesis of copolymer 3, 11.6 g of acetyl sugar methacrylate 1 was changed to 11.9 g of acetyl sugar methacrylate 2, 3.4 g of methyl methacrylate was changed to 3.3 g of methyl 2-chloroacrylate, and 4.2 g of styrene. To 3.9 g of α-methylstyrene and 0.9 g of 2,2,2-trifluoroethyl methacrylate 1.0 g of 2,2,3,3,3-pentafluoropropylmethacrylate (manufactured by Sigma Aldrich). 10.5 g of copolymer 9 was obtained by the same method except that it was changed to. The structure of each structural unit of the obtained copolymer 9 is as follows.

[Example 10: Synthesis of copolymer 10]
(Synthesis of Acetyl Sugar Methacrylate 1-Methyl Chloroacrylate-Methylstyrene-Trifluoroethyl Methacrylate Random Copolymer)
In the synthesis of the copolymer 3, the amount of acetyl sugar methacrylate 1 added was changed from 11.6 g to 10.9 g, 3.4 g of methyl methacrylate was changed to 3.8 g of methyl 2-chloroacrylate, and styrene 4. 10.7 g of the copolymer 10 was obtained by the same method except that 2 g was changed to 4.5 g of α-methylstyrene. The structure of each structural unit of the obtained copolymer 10 is as follows.

[Example 11: Synthesis of copolymer 11]
(Synthesis of Acetyl Sugar Methacrylate 1-Methyl Chloroacrylate-Methylstyrene-Trichloroethyl Acrylate Random Copolymer)
In the synthesis of the copolymer 3, the amount of acetyl sugar methacrylate 1 added was changed from 11.6 g to 11.1 g, 3.4 g of methyl methacrylate was changed to 3.9 g of methyl 2-chloroacrylate, and styrene 4. Change 2g to 4.0g of α-methylstyrene and change 0.9g of 2,2,2-trifluoroethyl methacrylate to 1.1g of 2,2,2-trichloroethyl acrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). The copolymer 11 was obtained in the same manner except for the above. The structure of each structural unit of the obtained copolymer 11 is as follows.

[Example 12: Synthesis of copolymer 12]
(Synthesis of Acetyl Sugar Methacrylate 1-Fluoroacrylate Methyl-Methylstyrene-Trifluoroethyl Methacrylate Random Copolymer)
In the synthesis of the copolymer 3, the amount of acetyl sugar methacrylate 1 added was changed from 11.6 g to 11.2 g, and 3.4 g of methyl methacrylate was added to methyl 2-fluoroacrylate (manufactured by Fujifilm Wako Junyaku Co., Ltd.). 11.0 g of the copolymer 12 was obtained by the same method except that the amount was changed to 4 g and 4.2 g of styrene was changed to 4.6 g of α-methylstyrene. The structure of each structural unit of the obtained copolymer 12 is as follows.

[Example 13: Synthesis of copolymer 13]
(Synthesis of acetyl sugar styrene)
20 g of xylose was added to a mixed solution of 250 g of acetic anhydride (manufactured by Wako Pure Chemical Industries, Ltd.) and 320 g of acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), and the mixture was stirred at 30 ° C. for 2 hours. About 5 times the amount of cold water of the solution was slowly added with stirring, and after stirring for 2 hours, the mixture was allowed to stand overnight to precipitate crystals, and the crystals were filtered to synthesize 30 g of acetyl sugar. Silicon oil while stirring 10.8 g (90 mmol) of acetyl sugar 4-vinylphenol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 32.2 g (32 mmol) of acetyl sugar and 0.5 g of zinc chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) It was heated in a bath at 160 ° C. for 30 minutes. The melting mixture was cooled to about 60 ° C. and dissolved in 200 mL of benzene (manufactured by Wako Pure Chemical Industries, Ltd.). This solution was washed twice with water and then with 1M sodium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) until the aqueous phase became almost colorless. Subsequently, it was washed twice with water, dried, and concentrated under reduced pressure to obtain 26.5 g of acetyl sugar styrene. The structure of the obtained acetyl sugar styrene is as follows.

(Synthesis of Acetyl Styrene-Methyl Chloroacrylate-Methylstyrene-Trifluoroethyl Methacrylate Random Copolymer)
In the synthesis of the copolymer 3, 11.6 g of acetyl sugar methacrylate 1 was changed to 11.2 g of acetyl sugar styrene, 3.4 g of methyl methacrylate was changed to 3.7 g of methyl 2-chloroacrylate, and 4.2 g of styrene was further changed. Copolymer 13 10.8 g was obtained by the same method except that the amount was changed to 4.3 g of α-methylstyrene. The structure of each structural unit of the obtained copolymer 13 is as follows.

[Comparative Example 1: Synthesis of Copolymer 14]
(Synthesis of Methyl Chloroacrylate-Methylstyrene-Trifluoromethylmethacrylate Random Copolymer)
After putting 10.0 g of α-methylstyrene, 8.9 g of methyl 2-chloroacrylate and 1.4 g of 2,2,2-trifluoroethyl methacrylate in a flask, 100 g of THF as a solvent and azobisisobuty as a polymerization initiator After adding 0.8 g of lonitrile, the flask was sealed and replaced with nitrogen. The temperature was raised to 78 ° C. under a nitrogen atmosphere, and the mixture was stirred for 6 hours. Then, the temperature was returned to room temperature, the flask was placed under the atmosphere, and 300 g of methanol was added dropwise to the obtained solution to precipitate the polymer. Then, the solution containing the precipitated polymer was suction-filtered to obtain 14.0 g of a white copolymer. The structure of each structural unit of the obtained copolymer 14 is as follows.

[Comparative Example 2: Synthesis of Copolymer 15]
(Synthesis of Acetyl Sugar Methacrylate 1-Methyl Chloroacrylate Random Copolymer)
In the synthesis of copolymer 2, the amount of acetyl sugar methacrylate 1 added was changed from 14.7 g to 11.1 g, the amount of methyl 2-chloroacrylate added was changed from 4.6 g to 4.5 g, and further 2, 12.0 g of the copolymer 15 was obtained by the same method except that 4.4 g of α-methylstyrene was added without adding 2,2-trifluoroethyl methacrylate. The structure of each structural unit of the obtained copolymer 15 is as follows.

[Comparative Example 3: Synthesis of Copolymer 16]
(Synthesis of Acetyl Sugar Methacrylate-Methyl Chloroacrylate Random Copolymer)
In the synthesis of copolymer 1, the amount of acetyl sugar methacrylate 1 added was changed from 19.5 g to 14.8 g, and 2-chloroacrylic was added without adding 0.5 g of 2,2,2-trifluoroethyl methacrylate. 10.5 g of the copolymer 16 was obtained by the same method except that 5.2 g of methyl oxyate was added. The structure of each structural unit of the obtained copolymer 16 is as follows.

[Comparative Example 4: Synthesis of Copolymer 17]
(Synthesis of adamantyl methacrylate-methyl-methylstyrene-trifluoroethyl methacrylate random copolymer)
In the synthesis of copolymer 3, 11.6 g of acetylsaccharide methacrylate 1 was changed to 8.7 g of 1-adamantyl methacrylate (manufactured by Tokyo Kasei Kogyo Co., Ltd.), and 3.4 g of methyl methacrylate was changed to 4.7 g of methyl 2-chloroacrylate. The same applies except that 4.2 g of styrene was changed to 5.6 g of α-methylstyrene, and the amount of 2,2,2-trifluoroethyl methacrylate added was changed from 0.9 g to 1.1 g. To obtain 8.4 g of the copolymer 17 by the above method. The structure of each structural unit of the obtained copolymer 17 is as follows.

[Comparative Example 5: Synthesis of Copolymer 18]
(Synthesis of Acetyl Sugar Methacrylate-Methyl Methacrylate-Methylstyrene Random Copolymer)
In the synthesis of copolymer 2, the amount of acetyl sugar methacrylate 1 added was changed from 14.7 g to 11.5 g, 4.6 g of methyl 2-chloroacrylate was changed to 3.9 g of methyl methacrylate, and further 2, Copolymer 189.8 g was obtained by the same method except that 4.6 g of α-methylstyrene was added without adding 0.7 g of 2-trifluoroethyl methacrylate. The structure of each structural unit of the obtained copolymer 18 is as follows.

[Analysis of copolymer]
<Weight average molecular weight>
The weight average molecular weight of the copolymer was measured by the gel permeation chromatogram (GPC) method.
GPC column: Shodex K-806M / K-802 connecting column (manufactured by Showa Denko KK)
Column temperature: 40 ° C
Moving layer: Chloroform detector: RI
After all the polymerization was completed, the degree of polymerization was confirmed by the GPC method, and it was confirmed that the random copolymer having the desired degree of polymerization and average molecular weight was formed. The number average molecular weight Mn of each copolymer was 50,000.

<Unit (a): Unit (b): Unit (c): Unit (d) ratio>
The ratio of each unit of the copolymer was calculated by measuring ¹ H-NMR of the polymer using JNM-ECS-400 (manufactured by JEOL Ltd.). From the peak area derived from each unit, the ratio (molar ratio) of the unit (a) and the unit (b): unit (c): unit (d) of the copolymer was calculated. The molar ratio indicates the ratio of the number of units present in the copolymer.

[Evaluation of copolymer solubility]
The synthesized copolymer was weighed and dissolved in propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Inc.) at 23 ° C. so as to be 3.0% by mass, and the solubility was visually confirmed and evaluated according to the following criteria.
◯: The solution is transparent and there is no white turbidity or precipitation △: The solution is turbid but there is no precipitation ×: Precipitation is observed in the solution

[Preparation of sample for resist evaluation]
The synthesized copolymer was weighed and dissolved in propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Inc.) at 23 ° C. to a concentration of 3.0% by mass. This solution was spin-coated on a silicon wafer so as to have a film thickness of 100 nm, heated on a hot plate at 180 ° C. for 2 minutes, and fired. An electron beam drawing device ELS-F125 (manufactured by Elionix Inc.) was used to irradiate the fired silicon wafer with an electron beam under the conditions of an acceleration voltage of 50 kV and a current of 500 pA (wavelength 0.0053 nm) to draw a latent image. Then, the steps shown below were performed to prepare a sample for sensitivity and resolution evaluation, and the sensitivity was evaluated.

[Sensitivity evaluation]
The dose amount is 15 μC / cm ² , 30 μC / cm ² , 45 μC / cm ² , 60 μC / cm ² , 160 μC / cm ² , respectively, the line width is 100 nm on the resist film, and the line: space ratio is 1: 1. I drew a latent image of Andspace. The silicon wafer after drawing was immersed in amyl acetate (manufactured by Tokyo Kasei Co., Ltd.) at 23 ° C. for development. After development, it was dried with a nitrogen blow to prepare a sample for sensitivity evaluation.
The surface and cross section of the line-and-space portion were observed using a scanning electron microscope (SEM) JSM7800F (manufactured by JEOL Ltd.) under the conditions of an acceleration voltage of 5 kV, an emission current of 86.0 μA, and a magnification of 100,000 times, and the sensitivity was measured. confirmed. The condition was evaluated according to the following evaluation criteria. When the line-and-space pattern was developed with a dose amount of 45 μC / cm ² or less, the sensitivity was evaluated as good.
○: Line and space pattern is developed ×: Line and space pattern is not developed

When the resist film was formed by using the copolymer obtained in the examples, the sensitivity of the resist film was high.

10 Substrate 40 Resist film

Claims (12)

A resist material containing a polymer containing a unit derived from the structure represented by the following general formula (101) and a unit derived from the structure represented by the following general formula (104);

In the general formula (101), R ¹ may independently have a hydrogen atom, an alkyl group which may have a substituent, an acyl group which may have a substituent, and a substituent. Represents an allyl group, an alkoxy group which may have a substituent or an alkylsilyl group which may have a substituent, and a plurality of R ^1s may be the same or different; R ¹¹ is hydrogen. Represents an alkyl group which may have an atom or a substituent; R ² represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ¹ is a single bond or a link. Represents a group;
In the general formula (104), X ³ represents an alkyl halide group, R ⁵ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ⁴ represents a single bond. Or represents a linking group. The resist material according to claim 1, wherein the polymer further contains a unit derived from the structure represented by the following general formula (102);

In the general formula (102), X ¹ is an alkyl group which may have a substituent (excluding those containing a halogen atom in the substituent), an acyl group which may have a substituent or a substituent. Represents an allyl group which may have a group; R ³ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group, and Y ² represents a single bond or a linking group. .. The resist material according to claim 1 or 2, wherein the polymer further contains a unit derived from the structure represented by the following general formula (103);

In the general formula (103), X ² represents an aryl group which may have a substituent; R ⁴ represents a hydrogen atom, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom or an alkyl halide group. , Y ³ represent a single bond or a linking group. The resist material according to any one of claims 1 to 3, wherein the content of the unit derived from the structure represented by the general formula (104) in the polymer is 1 to 40 mol%. The resist material according to any one of claims 1 to 4, wherein R ² is a fluorine atom, a chlorine atom or a bromine atom in the general formula (101). The resist material according to any one of claims 1 to 5, wherein R ¹¹ is a hydrogen atom in the general formula (101). The resist material according to any one of claims 2 to 6, wherein R ³ is a fluorine atom, a chlorine atom or a bromine atom in the general formula (102). A resist film formed from the resist material according to any one of claims 1 to 7. A step of applying the resist material according to any one of claims 1 to 7 onto a substrate to form a resist film, and
The exposure process and
A development process and a pattern forming method including. The pattern forming method according to claim 9, further comprising a metal introduction step before the developing step. The pattern forming method according to claim 9 or 10, wherein in the exposure step, the resist film is irradiated with an electromagnetic wave having a wavelength of 15 nm or less. The pattern forming according to any one of claims 9 to 11, wherein the developing solution used in the developing step contains at least one selected from the group consisting of an ester compound, a ketone compound and an alcohol compound. Method.

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