JP2020204765A - Radiation-sensitive resin composition and resist pattern-forming method - Google Patents

Abstract

To provide: a radiation-sensitive resin composition with high sensitivity, favorable LWR performance and wide process latitude; and a resist pattern-forming method.SOLUTION: A radiation-sensitive resin composition contains a polymer, a radiation-sensitive acid generator, and a compound represented by formula (2) in the figure. The polymer includes a first structural unit including a phenolic hydroxyl group, a second structural unit including a group represented by formula (1) in the figure, and a third structural unit including an acid-labile group.SELECTED DRAWING: None

Description

The present invention relates to a radiation-sensitive resin composition and a resist pattern forming method.

Radiation-sensitive resin compositions used for micromachining by lithography include far-ultraviolet rays such as ArF excima laser light (wavelength 193 nm) and KrF excima laser light (wavelength 248 nm), and extreme ultraviolet rays (EUV) (wavelength 13.5 nm). An acid is generated in the exposed part by irradiation with radiation such as an electromagnetic wave or a charged particle beam such as an electron beam, and a chemical reaction using this acid as a catalyst causes a difference in the dissolution rate of the exposed part and the unexposed part in the developing solution. , A resist pattern is formed on the substrate.

In addition to having good sensitivity to exposure light such as extreme ultraviolet rays and electron beams, the radiation-sensitive composition is also excellent in LWR (Line Width Roughness) performance, which indicates uniformity of line width. Required.

In response to these requirements, the types and molecular structures of polymers and other components used in the radiation-sensitive resin composition have been studied, and the combinations thereof have also been studied in detail (Japanese Patent Laid-Open No. 2009-244805). (Refer to JP-A-2004-012510 and JP-A-2017-141373).

JP-A-2009-244805 Japanese Unexamined Patent Publication No. 2004-012510 JP-A-2017-141373

With the further miniaturization of the resist pattern, the influence of slight blurring of exposure / development conditions on the shape of the resist pattern and the occurrence of defects is increasing. There is also a demand for a radiation-sensitive resin composition having a wide process window (process margin) capable of absorbing such slight fluctuations in process conditions. However, the above-mentioned conventional radiation-sensitive resin composition cannot satisfy these requirements.

The present invention has been made based on the above circumstances, and an object of the present invention is a feeling that a resist pattern having good sensitivity to exposure light, excellent LWR performance, and a wide process window can be formed. It is an object of the present invention to provide a radioactive resin composition and a method for forming a resist pattern.

（式（１）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６は、それぞれ独立して、水素原子、フッ素原子、塩素原子、臭素原子、ヨウ素原子又は炭素数１〜１０の１価のフッ素化炭化水素基である。但し、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６のうちの少なくとも１つはフッ素原子又はフッ素化炭化水素基である。Ｒ^Ａは、水素原子又は炭素数１〜２０の１価の有機基である。＊は、上記第２構造単位における上記式（１）で表される基以外の部分との結合部位を示す。）

（式（２）中、Ｒ^７、Ｒ^８及びＲ^９は、それぞれ独立して、水素原子、フッ素原子若しくは炭素数１〜４０の１価の有機基であるか、又はこれらの基のうちの２つ以上が互いに合わせられこれらが結合する炭素原子と共に構成される環員数３〜２０の環構造の一部である。Ａ^＋は、１価の感放射線性オニウムカチオンである。） The invention made to solve the above problems includes a first structural unit containing a phenolic hydroxyl group, a second structural unit containing a group represented by the following formula (1), and a third structural unit containing an acid dissociable group. A polymer (hereinafter, also referred to as “[A] polymer”), a radiation-sensitive acid generator (hereinafter, also referred to as “[B] acid generator”), and a compound represented by the following formula (2). It is a radiation-sensitive resin composition containing (hereinafter, also referred to as “[C] compound”).

(In formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are independently hydrogen atoms, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms or 1 to 1 carbon atoms. It is a monovalent fluorinated hydrocarbon group of 10. However, at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is a fluorine atom or a fluorinated hydrocarbon group. ^RA is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. * Indicates a bonding site with a portion other than the group represented by the above formula (1) in the above second structural unit. )

(In the formula (2), R ⁷ , R ⁸ and R ⁹ are independently hydrogen atoms, fluorine atoms or monovalent organic groups having 1 to 40 carbon atoms, or among these groups. It is a part of a ring structure having 3 to 20 ring members, in which two or more are combined with each other and composed of carbon atoms to which they are bonded. A ⁺ is a monovalent radiosensitive onium cation.)

Another invention made to solve the above problems includes a step of directly or indirectly coating the substrate with the radiation-sensitive resin composition, a step of exposing the resist film formed by the coating step, and a step of exposing the resist film formed by the coating step. This is a resist pattern forming method including a step of developing a resist film after the exposure step.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, it is possible to form a resist pattern having good sensitivity to exposure light, excellent LWR performance, and a wide process window. Therefore, these can be suitably used for processing processes of semiconductor devices, which are expected to be further miniaturized in the future.

<Radiation-sensitive resin composition>
The radiation-sensitive resin composition contains a [A] polymer, a [B] acid generator, and a [C] compound. The radiation-sensitive resin composition may contain a solvent (hereinafter, also referred to as “[D] organic solvent”) as a suitable component, and may contain other optional components as long as the effects of the present invention are not impaired. It may be contained.

The radiation-sensitive resin composition contains the [A] polymer, the [B] acid generator, and the [C] compound, so that the sensitivity to exposure light is good, the LWR performance is excellent, and the process window. Can form a wide resist pattern. The reason why the radiation-sensitive resin composition exerts the above-mentioned effect by having the above-mentioned constitution is not always clear, but it can be inferred as follows, for example. That is, the [A] polymer contained in the radiation-sensitive resin composition has a first structural unit containing a phenolic hydroxyl group and a second structural unit containing a group represented by the above formula (1). Solubility in developer is improved. Further, when the radiation-sensitive resin composition contains the [C] compound, the solubility in a developing solution is further improved. As a result, it is considered that the radiation-sensitive resin composition can form a resist pattern having good sensitivity to exposure light, excellent LWR performance, and a wide process window.

Hereinafter, each component contained in the radiation-sensitive resin composition will be described.

<[A] Polymer>
The polymer [A] has a first structural unit containing a phenolic hydroxyl group (hereinafter, also simply referred to as “first structural unit”) and a second structural unit containing a group represented by the above formula (1) (hereinafter, simply referred to as “first structural unit”). It has a "second structural unit") and a third structural unit containing an acid-dissociable group (hereinafter, also simply referred to as "third structural unit"). [A] The polymer may have other structural units other than the above-mentioned first structural unit, second structural unit and third structural unit. [A] The polymer may have one or more structural units.

Hereinafter, each structural unit of the [A] polymer will be described.

[First structural unit]
The first structural unit is a structural unit containing a phenolic hydroxyl group. The "phenolic hydroxyl group" refers not only to the hydroxy group directly connected to the benzene ring but to all the hydroxy groups directly connected to the aromatic ring. [A] When the polymer has the first structural unit, the hydrophilicity of the resist film can be enhanced, the solubility in the developing solution can be appropriately adjusted, and in addition, the resist pattern adheres to the substrate. The sex can be improved. Further, when extreme ultraviolet rays or electron beams are used as the radiation to be irradiated in the exposure step in the resist pattern forming method described later, the sensitivity to the exposure light can be further improved.

Examples of the first structural unit include a structural unit represented by the following formula (3).

In the above formula (3), R ¹⁰ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹¹ is a single bond, -O-, -COO- or -CONH-. Ar is a group obtained by removing (p + q + 1) hydrogen atoms on an aromatic ring from an array having 6 to 20 ring members. p is an integer from 0 to 10. When p is 1, R ¹² is a monovalent organic group or halogen atom having 1 to 20 carbon atoms. When p is 2 or more, the plurality of R ^12s are the same or different from each other and are monovalent organic groups or halogen atoms having 1 to 20 carbon atoms, or two or more of the plurality of R ^12s are combined with each other. It is a part of a ring structure having 4 to 20 ring members, which is composed of a carbon chain to which these are bonded. q is an integer of 1-11. However, p + q is 11 or less.

As R ¹⁰ , a hydrogen atom or a methyl group is preferable from the viewpoint of copolymerizability of the monomer giving the first structural unit.

When R ¹¹ is -COO-, the oxyoxygen atom is preferably bonded to Ar, and when R ¹¹ is -CONH-, the nitrogen atom is preferably bonded to Ar. That is, if ** indicates a binding site with Ar, -COO- is preferably -COO-**, and -CONH- is preferably -CONH-**. The R ^11, a single bond or -COO- is more preferably a single bond.

The "number of ring members" refers to the number of atoms constituting the rings of the alicyclic structure, the aromatic carbocyclic structure, the aliphatic heterocyclic structure and the aromatic heterocyclic structure, and in the case of a polycycle, it constitutes this polycycle. The number of atoms.

Examples of the arene having 6 to 20 ring members that give Ar include benzene, naphthalene, anthracene, phenanthrene, tetracene, pyrene and the like. As Ar, benzene or naphthalene is preferable, and benzene is more preferable.

"Organic group" means a group containing at least one carbon atom. The "carbon number" means the number of carbon atoms constituting the group. Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ¹² include a monovalent hydrocarbon group having 1 to 20 carbon atoms and a divalent heteroatomic group between carbons of the hydrocarbon group. A group containing a group (α), a group (β) in which a part or all of hydrogen atoms contained in the above hydrocarbon group and the above divalent heteroatom-containing group are substituted with a monovalent heteroatom-containing group, the above. Examples thereof include a group (γ) in which a hydrocarbon group, a group (α) or a group (β) and a divalent heteroatom-containing group are combined.

The "hydrocarbon group" includes a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. This "hydrocarbon group" may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The "chain hydrocarbon group" refers to a hydrocarbon group composed only of a chain structure without containing a cyclic structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The "alicyclic hydrocarbon group" refers to a hydrocarbon group containing only an alicyclic structure and not an aromatic ring structure as a ring structure, and is a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Contains both hydrocarbon groups. However, it does not have to be composed only of an alicyclic structure, and a chain structure may be included as a part thereof. The "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it does not have to be composed only of an aromatic ring structure, and a chain structure or an alicyclic structure may be included as a part thereof.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and 6 carbon atoms. Examples thereof include monovalent aromatic hydrocarbon groups of ~ 20.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include an alkyl group such as a methyl group, an ethyl group, an n-propyl group and an i-propyl group, and an alkenyl group such as an ethenyl group, a propenyl group and a butenyl group. , Ethynyl group, propynyl group, alkynyl group such as butynyl group and the like.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include an alicyclic saturated hydrocarbon group such as a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a tricyclodecyl group and a tetracyclododecyl group. Examples thereof include an alicyclic unsaturated hydrocarbon group such as a cyclopentenyl group, a cyclohexenyl group, a norbornenyl group, a tricyclodecenyl group and a tetracyclododecenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include an aryl group such as a phenyl group, a tolyl group, a xsilyl group, a naphthyl group and an anthryl group, a benzyl group, a phenethyl group, a naphthylmethyl group and an anthrylmethyl group. Examples include an aralkyl group such as a group.

Examples of the heteroatom constituting the monovalent and divalent heteroatom-containing groups include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, a halogen atom and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the divalent heteroatom-containing group include -O-, -CO-, -S-, -CS-, -NR'-, a group in which two or more of these are combined, and the like. R'is a hydrogen atom or a monovalent hydrocarbon group.

As R ¹² , a monovalent hydrocarbon group is preferable, and an alkyl group is more preferable.

Examples of the ring structure having 4 to 20 ring members, in which two or more of the plurality of R ^12s are combined with each other and together with the carbon chain to which they are bonded, include a cyclopentane structure, a cyclohexane structure, a cyclopentene structure, and a cyclohexene structure. An alicyclic structure and the like can be mentioned.

As p, 0 to 2, 0 or 1, is more preferable, and 0 is even more preferable.

As q, 1 to 3 is preferable, and 1 or 2 is more preferable.

Examples of the first structural unit include structural units represented by the following formulas (3-1) to (3-12).

In the above formulas (3-1) to (3-12), R ¹⁰ has the same meaning as the above formula (3).

As the first structural unit, the structural unit represented by the above formula (3-1) or (3-2) is preferable.

The lower limit of the content ratio of the first structural unit in the [A] polymer is preferably 10 mol%, more preferably 15 mol%, and 20 mol% with respect to all the structural units constituting the [A] polymer. More preferably, 25 mol% is particularly preferable. The upper limit of the content ratio is preferably 70 mol%, more preferably 65 mol%, further preferably 60 mol%, and particularly preferably 55 mol%. By setting the content ratio of the first structural unit in the above range, the sensitivity and LWR performance of the resist pattern formed by the radiation-sensitive resin composition to exposure light can be further improved, and the process window can be further expanded. be able to.

[Second structural unit]
The second structural unit is a structural unit containing a group represented by the following formula (1).

In the above formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are independently hydrogen atoms, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms or 1 to 1 carbon atoms. It is a monovalent fluorinated hydrocarbon group of 10. However, at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is a fluorine atom or a fluorinated hydrocarbon group. ^RA is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. * Indicates the binding site of the second structural unit with a portion other than the group represented by the above formula (1).

Examples of the hydrocarbon group substituted with a fluorine atom in the monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ include the above. such same groups as the hydrocarbon groups exemplified as R ¹² in formula (3) below. Specifically, examples of the monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms include a fluorinated alkyl group having 1 to 10 carbon atoms.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by ^RA include a group similar to the monovalent organic group exemplified as R ¹² of the above formula (3).

As R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ , a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms is preferable, and a fluorine atom or 1 of 1 to 10 carbon atoms is preferable. Valuable alkyl fluorinated groups are more preferred, and fluorinated atoms are even more preferred.

At least ^{one of} R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is a fluorinated atom or fluorinated hydrocarbon group, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and At least two of R ⁶ are preferably fluorine atoms or fluorinated hydrocarbon groups, at least two of R ¹ , R ² and R ³ and at least two of R ⁴ , R ⁵ and R ^6. It is more preferable that one is a fluorine atom or a fluorinated hydrocarbon group, and it is further preferable that R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are a fluorine atom or a fluorinated hydrocarbon group, and R ^{1, R 2, R 3,} R 4, and particularly preferably ^{R 5} and ^{R 6} is a fluorine atom.

^A hydrogen atom is preferable as ^RA .

Examples of the second structural unit include structural units represented by the following formulas (1-1) or (1-2).

In the above formulas (1-1) and (1-2), ^Ra1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, respectively, independently of each other. X is a group represented by the above formula (1).

In the above formula (1-1), L is a single bond or -COO-. ^Ra2 is a (n + 1) -valent organic group having 1 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, a plurality of X's are the same or different from each other.

In the above formula (1-2), ^Ra3 is a divalent hydrocarbon group having 1 to 10 carbon atoms. ^Ra4 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^a5 and R ^a6 are independently hydrogen atoms or monovalent hydrocarbon groups having 1 to 10 carbon atoms, or are composed of carbon atoms in which R ^a5 and R ^a6 are bonded to each other and are bonded to each other. It is a part of a ring structure having 3 to 20 ring members.

As ^Ra1 , a hydrogen atom or a methyl group is preferable from the viewpoint of copolymerizability of the monomer giving the second structural unit.

As L, -COO- is preferable. When L is −COO−, it is preferable that the ^oxyoxygen atom binds to ^Ra2 . That is, when *** is to indicate a binding site for ^{R a2,} -COO- is, -COO - is preferably ***.

Examples of R ^a2 include a monovalent organic group exemplified as R ¹² of the above formula (3) from which n hydrogen atoms have been removed. As R ^a2 , a hydrocarbon group is preferable, a chain hydrocarbon group or an alicyclic hydrocarbon group is more preferable, a saturated chain hydrocarbon group or an alicyclic saturated hydrocarbon group is more preferable, and an alicyclic saturated hydrocarbon group is more preferable. Hydrocarbon groups are particularly preferred.

As n, 1 or 2 is preferable, and 1 is more preferable.

Examples of R ^a3 include a monovalent hydrocarbon group exemplified as R ¹² of the above formula (3) from which one hydrogen atom has been removed. As ^Ra3 , a chain hydrocarbon group is preferable, and a saturated chain hydrocarbon group is more preferable.

Examples of R ^a4 include a group similar to the hydrocarbon group exemplified as R ¹² of the above formula (3). As R ^a4 , a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms is preferable, and an aryl group is more preferable.

Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ^a5 and R ^a6 include a group similar to the hydrocarbon group exemplified as R ^{12 in the} above formula (3). Hydrogen atoms are preferable as R ^a5 and R ^a6 .

Examples of the ring structure having 3 to 20 ring members, in which R ^a5 and Ra ⁶ are bonded to each other and formed together with the carbon atom to which they are bonded, include an alicyclic structure having 3 to 20 ring members.

Among the second structural units, examples of the structural unit represented by the above formula (1-1) include structural units represented by the following formulas (1-1-1) to (1-1-3). Be done.

In the above formulas (1-1-1) to (1-1-3), ^Ra1 has the same ^meaning as the above formula (1-1).

Among the second structural units, examples of the structural unit represented by the above formula (1-2) include a structural unit represented by the following formula (1-2-1).

In the above formula (1-2-1), ^Ra1 has the same ^meaning as the above formula (1-2).

As the second structural unit, the structural unit represented by the above formula (1-1-1) or (1-2-1) is preferable.

The lower limit of the content ratio of the second structural unit in the [A] polymer is preferably 3 mol%, more preferably 5 mol%, and 10 mol% with respect to all the structural units constituting the [A] polymer. More preferred. The upper limit of the content ratio is preferably 50 mol%, more preferably 45 mol%, still more preferably 40 mol%. By setting the content ratio of the second structural unit within the above range, the sensitivity and LWR performance of the resist pattern formed by the radiation-sensitive resin composition to exposure light can be further improved, and the process window can be further expanded. be able to.

[Third structural unit]
The third structural unit is a structural unit containing an acid dissociative group. The "acid dissociative group" is a group that replaces a hydrogen atom such as a carboxy group or a phenolic hydroxyl group, and means a group that dissociates by the action of an acid. Since the [A] polymer has a third structural unit having an acid dissociative group, the acid dissociative group is dissociated in the exposed portion by the action of the acid generated from the [B] acid generator by the exposure, and the exposed portion and the exposed portion A resist pattern can be formed due to the difference in solubility in the developing solution between the unexposed portion and the unexposed portion.

Examples of the third structural unit include structural units represented by the following formulas (4-1A), (4-1B), (4-2A), or (4-2B). In Formula (4-1A) ~ (4-2B), -CR X R Y R Z or ^-CR U ^R V binding to oxy oxygen atom derived from a carboxy group or a phenolic hydroxy group (OR ^W) is It is an acid dissociative group.

In the above formulas (4-1A), (4-1B), (4-1C), (4-2A) and (4-2B), ^RT is independently a hydrogen atom, a fluorine atom and a methyl group. Alternatively, it is a trifluoromethyl group.

In the formula (4-1A) and (4-1B), ^{R X} is independently a monovalent hydrocarbon group having a hydrogen atom or a C 1-20. ^RY and R ^Z are independently monovalent hydrocarbon groups having 1 to 20 carbon atoms, or the number of rings composed of carbon atoms in which ^RY and R ^Z are combined with each other and bonded to each other. It is part of the alicyclic structure of 3-20.

In the above formula (4-1C), ^RC is a hydrogen atom. R ^D and ^{R E} are each independently a monovalent hydrocarbon group having a hydrogen atom or a C 1-20. R ^F is ^a divalent hydrocarbon group R C, carbon atoms constituting the unsaturated alicyclic structure ring members 4 to 20 together with the carbon atom ^{to which R D} and ^{R E} are respectively coupled to 20.

In the formula (4-2A) and (4-2B), ^{R U} and ^{R V} are each independently a monovalent hydrocarbon group having a hydrogen atom or a carbon number of 1 to 20, ^{R W} are each independently, or a monovalent hydrocarbon group having 1 to 20 carbon atoms, the alicyclic structure composed ring members 3 to 20 together with the carbon atom to which R ^U and R ^V are combined they are bound to each other one either a part, or R ^U and R ^W are carbon atoms and R ^W that keyed R ^U, bonded to each other is part of the aliphatic heterocyclic structure consisting ring members 5 to 20 together with the oxygen atom bonded ..

As the ^RT , a hydrogen atom or a methyl group is preferable from the viewpoint of copolymerizability of the monomer giving the third structural unit.

^{R X, R Y, R Z} , R D, R E, R U, the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by ^{R V} and ^{R W,} for example, the above formula (3) R Examples thereof include a group similar to the hydrocarbon group exemplified as No. ¹² .

Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^F, for example, the formula monovalent hydrocarbon group obtained by removing one hydrogen atom from the groups exemplified as R ¹² in (3) or the like Can be mentioned.

R ^Y and R ^Z or R ^U and The alicyclic structure formed ring members 3 to 20 together with the carbon atom to which R ^V is combined they are bound together, for example, cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane Monocyclic saturated alicyclic structure, norbornene structure, adamantan structure, tricyclodecane structure, tetracyclododecane structure and other polycyclic saturated alicyclic structure, cyclopropene structure, cyclobutene structure, cyclopentene structure, cyclohexene structure, etc. Examples thereof include a monocyclic unsaturated alicyclic structure, a norbornene structure, a tricyclodecene structure, a tetracyclododecene structure, and other polycyclic unsaturated alicyclic structures.

R ^U and the aliphatic heterocyclic structure consisting ring members 5 to 20 together with the oxygen atom to which R ^W is combined with each other, R ^U, carbon atoms bonded and R ^W are attached, for example, oxacyclobutane structure, oxacyclopentane Examples thereof include a structure, a saturated oxygen-containing heterocyclic structure such as an oxacyclohexane structure, an oxacyclobutane structure, an oxacyclopentene structure, and an unsaturated oxygen-containing heterocyclic structure such as an oxacyclohexene structure.

R ^F is R ^C, the unsaturated alicyclic structure ring members 4-20 which constitute together with the carbon atom to which R ^D and R ^E are respectively coupled, for example cyclobutene structure, cyclopentene structure, cyclohexene structure, unsaturated such as norbornene structure An alicyclic structure and the like can be mentioned.

The R ^X, preferably a hydrocarbon group, more preferably a chain hydrocarbon group or an aromatic hydrocarbon group, more preferably an alkyl group or an aryl group.

As ^RY and R ^Z , a hydrocarbon group is preferable, a chain hydrocarbon group or an alicyclic hydrocarbon group is more preferable, and an alkyl group or an alicyclic saturated hydrocarbon group is further preferable.

The R ^U, preferably a hydrogen atom or a hydrocarbon group, more preferably a hydrogen atom.

The R ^V and R ^W, preferably a hydrocarbon group, is a chain hydrocarbon group is more preferable.

As the third structural unit, the structural unit represented by the above formula (4-1A) is preferable.

The lower limit of the content ratio of the third structural unit in the [A] polymer is preferably 5 mol%, more preferably 10 mol%, and 15 mol% with respect to all the structural units constituting the [A] polymer. More preferred. The upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, and even more preferably 60 mol%. By setting the content ratio of the third structural unit within the above range, the sensitivity and LWR performance of the resist pattern formed by the radiation-sensitive resin composition to exposure light can be further improved, and the process window can be further expanded. be able to.

[Other structural units]
Other structural units include, for example, a lactone structure, a cyclic carbonate structure, a sultone structure or a structural unit containing a combination thereof, a structural unit containing an alcoholic hydroxyl group other than the second structural unit, and a structural unit derived from benzyl (meth) acrylate. And so on. By further having these other structural units, the polymer [A] can further appropriately adjust the solubility in the developing solution, and as a result, the resist formed by the radiation-sensitive resin composition. The sensitivity of the pattern to the exposure light and the LWR performance can be further improved, and the process window can be further expanded. Further, the adhesion between the resist pattern and the substrate can be further improved.

Examples of the structural unit containing the lactone structure, the cyclic carbonate structure, the sultone structure, or a combination thereof include a structural unit represented by the following formula.

In the above formula, ^RL1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

As the structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure or a combination thereof, a structural unit containing a lactone structure is preferable, a structural unit containing a norbornane lactone structure is more preferable, and it is derived from norbornane lactone-yl (meth) acrylate. The structural unit to be used is more preferable.

Examples of the structural unit containing an alcoholic hydroxyl group other than the second structural unit include a structural unit represented by the following formula.

In the above formula, ^RL2 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

When the polymer [A] has other structural units, the lower limit of the content ratio of the other structural units is preferably 1 mol%, more preferably 5 mol%, based on all the structural units in the [A] polymer. preferable. The upper limit of the content ratio is preferably 30 mol%, more preferably 20 mol%.

[A] As the lower limit of the polystyrene-equivalent weight average molecular weight (Mw) by gel permeation chromatography (GPC) of the polymer, 2,000 is preferable, 3,000 is more preferable, 4,000 is further preferable, and 5, 000 is particularly preferable. As the upper limit of the Mw, 11,000 is preferable, 10,000 is more preferable, 9,000 is further preferable, and 8,000 is particularly preferable. By setting the Mw of the polymer in the above range, the coatability of the radiation-sensitive resin composition can be improved, and as a result, the resist pattern formed by the radiation-sensitive resin composition can be improved. The sensitivity to exposure light and LWR performance can be further improved, and the process window can be further expanded.

[A] The upper limit of the ratio (Mw / Mn) of Mw to the polystyrene-equivalent number average molecular weight (Mn) of the polymer by GPC is preferably 2.50, more preferably 2.00, and even more preferably 1.75. The lower limit of the ratio is usually 1.00, preferably 1.10, and more preferably 1.20. By setting the Mw / Mn of the polymer in the above range, the coatability of the radiation-sensitive resin composition can be further improved.

The Mw and Mn of the polymer in the present specification are values measured by gel permeation chromatography (GPC) under the following conditions.
GPC column: 2 "G2000HXL", 1 "G3000HXL" and 1 "G4000HXL" from Toso Co., Ltd. Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Column temperature: 40 ° C
Detector: Differential refractometer Standard material: Monodisperse polystyrene

The lower limit of the content ratio of the [A] polymer in the radiation-sensitive resin composition is preferably 50% by mass, more preferably 60% by mass, and 70% by mass with respect to all the components other than the [D] organic solvent. Is more preferable, and 80% by mass is particularly preferable.

The polymer [A] can be synthesized, for example, by polymerizing a monomer giving each structural unit by a known method.

<[B] Acid generator>
[B] The acid generator is a substance that generates acid by irradiation with radiation. Examples of radiation include visible light, ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as electron beams and α-rays. The acid generated from the [B] acid generator by irradiation (exposure) of radiation dissociates the acid dissociative group contained in the third structural unit of the [A] polymer to generate a carboxy group, which is unexposed with the exposed portion. A resist pattern can be formed by causing a difference in the solubility of the [A] polymer in the developing solution. The radiation-sensitive resin composition contains the [B] acid generator in the form of a low molecular weight compound (hereinafter, also referred to as “[B] acid generator”) and incorporated as a part of the [A] polymer. Or both of these forms.

The lower limit of the temperature at which the acid dissociates the acid dissociative group is preferably 80 ° C., more preferably 90 ° C., and even more preferably 100 ° C. The upper limit of the temperature is preferably 130 ° C, more preferably 120 ° C, and even more preferably 110 ° C. The lower limit of the time for the acid to dissociate the acid dissociative group is preferably 10 seconds, more preferably 1 minute. The upper limit of the time is preferably 10 minutes, more preferably 2 minutes.

[B] Examples of the acid generated from the acid generator include sulfonic acid and imidic acid.

[B] Examples of the acid generator include onium salt compounds, N-sulfonyloxyimide compounds, sulfonimide compounds, halogen-containing compounds, diazoketone compounds and the like.

Examples of the onium salt compound include sulfonium salt, tetrahydrothiophenium salt, iodonium salt, phosphonium salt, diazonium salt, pyridinium salt and the like.

Specific examples of the [B] acid generator include compounds described in paragraphs [0080] to [0113] of JP-A-2009-134808.

Examples of the [B] acid generator that generates sulfonic acid by irradiation with radiation include a compound represented by the following formula (5) (hereinafter, also referred to as “compound (5)”). It is considered that when the [B] acid generator has the following structure, the diffusion length of the generated acid in the resist film is more appropriately shortened due to the interaction with the [A] polymer and the like, and as a result, the feeling is concerned. The sensitivity and LWR performance of the resist pattern formed by the radioactive resin composition to the exposure light can be further improved, and the process window can be further expanded.

In the above formula (5), R ^p1 is a monovalent group containing a ring structure having 5 or more ring members. R ^p2 is a divalent linking group. R ^p3 and R ^p4 are independently hydrogen atoms, fluorine atoms, monovalent hydrocarbon groups having 1 to 20 carbon atoms, or monovalent fluorinated hydrocarbon groups having 1 to 20 carbon atoms. R ^p5 and R ^p6 are independently fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 20 carbon atoms. n ^p1 is an integer from 0 to 10. n ^p2 is an integer from 0 to 10. n ^p3 is an integer from 0 to 10. However, n ^p1 + n ^p2 + n ^p3 is 1 or more and 30 or less. When n ^p1 is 2 or more, a plurality of R ^p2s are the same or different from each other. If n ^p2 is 2 or more, the plurality of ^{R p3} equal to or different from each other, a plurality of ^{R p4} are the same or different from each other. If n ^p3 is 2 or more, the plurality of ^{R p5} equal to or different from each other, a plurality of ^{R p6} are the same or different from each other. T ⁺ is a monovalent radiation-sensitive onium cation.

Examples of the monovalent group including a ring structure having 5 or more ring members represented by R ^p1 include a monovalent group including an alicyclic structure having 5 or more ring members and an aliphatic heterocyclic structure having 5 or more ring members. Examples thereof include a monovalent group, a monovalent group containing an aromatic carbocyclic ring structure having 5 or more ring members, and a monovalent group containing an aromatic heterocyclic structure having 5 or more ring members.

Examples of the alicyclic structure having 5 or more ring members include a monocyclic saturated alicyclic structure such as a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure, a cyclopentene structure, and a cyclohexene structure. Structure, cycloheptene structure, cyclooctene structure, monocyclic unsaturated alicyclic structure such as cyclodecene structure, norbornane structure, adamantan structure, tricyclodecane structure, polycyclic saturated alicyclic structure such as tetracyclododecan structure, norbornene structure, Examples thereof include a polycyclic unsaturated alicyclic structure such as a tricyclodecene structure.

Examples of the aliphatic heterocyclic structure having 5 or more ring members include a lactone structure such as a hexanolactone structure and a norbornane lactone structure, a sulton structure such as a hexanosulton structure and a norbornane sulton structure, an oxacycloheptane structure, and an oxanorbornane structure. Examples thereof include a nitrogen atom-containing heterocyclic structure such as an oxygen atom-containing heterocyclic structure, an azacyclohexane structure and a diazabicyclooctane structure, and a sulfur atom-containing heterocyclic structure such as a thiacyclohexane structure and a thianorbornane structure.

Examples of the aromatic carbocyclic ring structure having 5 or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, an anthracene structure and the like.

Examples of the aromatic heterocyclic structure having 5 or more ring members include an oxygen atom-containing heterocyclic structure such as a furan structure, a pyran structure, a benzofuran structure, and a benzopyran structure, and a nitrogen atom-containing heterocyclic structure such as a pyridine structure, a pyrimidine structure, and an indole structure. And so on.

As the lower limit of the number of ring members of the ring structure of R ^p1 , 6 is preferable, 8 is more preferable, 9 is further preferable, and 10 is particularly preferable. As the upper limit of the number of ring members, 15 is preferable, 14 is more preferable, 13 is further preferable, and 12 is particularly preferable. By setting the number of ring members in the above range, the diffusion length of the above-mentioned acid can be further appropriately shortened, and as a result, the sensitivity and LWR performance of the resist pattern formed by the radiation-sensitive resin composition to exposure light. Can be improved and the process window can be expanded further.

A part or all of the hydrogen atom of the ring structure of R ^p1 may be substituted with a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group and acyl group. Examples thereof include an asyloxy group. Of these, a hydroxy group is preferable.

As R ^p1 , a monovalent group containing an alicyclic structure having 5 or more ring members or a monovalent group containing an aliphatic heterocyclic structure having 5 or more ring members is preferable, and a monovalent group containing a polycyclic saturated alicyclic structure is preferable. , A monovalent group containing an oxygen atom-containing heterocyclic structure or a monovalent group containing a nitrogen atom-containing heterocyclic structure is more preferable, and an adamantyl group, a norbornane sulton-yl group or an azacyclohexane-yl group is further preferable.

Examples of the divalent linking group represented by R ^p2 include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, and a divalent hydrocarbon group. Among these, a carbonyloxy group, a sulfonyl group, an alkanediyl group or a divalent alicyclic saturated hydrocarbon group is preferable, and a carbonyloxy group or a sulfonyl group is more preferable.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 include an alkyl group having 1 to 20 carbon atoms. Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 include a fluorinated alkyl group having 1 to 20 carbon atoms. As R ^p3 and R ^p4 , a hydrogen atom, a fluorine atom or a fluorinated alkyl group is preferable, a fluorine atom or a perfluoroalkyl group is more preferable, and a fluorine atom or a trifluoromethyl group is further preferable.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p5 and R ^p6 include a fluorinated alkyl group having 1 to 20 carbon atoms. As R ^p5 and R ^p6 , a fluorine atom or a fluorinated alkyl group is preferable, a fluorine atom or a perfluoroalkyl group is more preferable, a fluorine atom or a trifluoromethyl group is further preferable, and a fluorine atom is particularly preferable.

As n ^p1 , 0 to 5 is preferable, 0 to 2 is more preferable, and 0 or 1 is further preferable.

The n ^p2 is preferably 0 to 5, more preferably 0 to 2, and even more preferably 0 or 1.

As the lower limit of n ^p3 , 1 is preferable, and 2 is more preferable. By setting n ^p3 to 1 or more, the strength of the acid generated from the compound (5) can be increased, and as a result, the sensitivity of the resist pattern formed by the radiation-sensitive resin composition to the exposure light and the LWR The performance can be further improved and the process window can be further expanded. As the upper limit of n ^p3 , 4 is preferable, 3 is more preferable, and 2 is further preferable.

As the lower limit of n ^p1 + n ^p2 + n ^p3 , 2 is preferable, and 4 is more preferable. As the upper limit of n ^p1 + n ^p2 + n ^p3 , 20 is preferable, and 10 is more preferable.

Examples of the monovalent radiation-sensitive onium cation represented by T ⁺ include a cation represented by the following formula (ra) (hereinafter, also referred to as “cation (ra)”) and the following formula (r−a). The cation represented by b) (hereinafter, also referred to as “cation (rb)”), the cation represented by the following formula (rc) (hereinafter, also referred to as “cation (rc)”), etc. Can be mentioned.

In the above formula (ra), R ^B3 and R ^B4 are independently monovalent organic groups having 1 to 20 carbon atoms. b3 is an integer from 0 to 11. When b3 is 1, ^RB5 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group or a halogen atom. When b3 is 2 or more, the plurality of ^RB5s are the same or different from each other and are monovalent organic groups having 1 to 20 carbon atoms, hydroxy groups, nitro groups or halogen atoms, or these groups are combined with each other. It represents a part of a ring structure having 4 to 20 ring members, which is composed of a carbon chain to which these are bonded. n _bb is an integer from 0 to 3.

The monovalent organic group having 1 to 20 carbon atoms represented by ^{R B3, R B4} and ^{R B5,} for example, the same groups as exemplified organic groups as ^{R 12} in the formula (3) below.

As R ^B3 and R ^B4 , monovalent unsubstituted hydrocarbon groups having 1 to 20 carbon atoms or hydrocarbon groups in which hydrogen atoms are substituted with substituents are preferable, and monovalent unsubstituted hydrocarbon groups having 6 to 18 carbon atoms are preferred. The aromatic hydrocarbon group or the aromatic hydrocarbon group in which the hydrogen atom is substituted with a substituent is more preferable, the substituted or unsubstituted phenyl group is further preferable, and the unsubstituted phenyl group is particularly preferable.

The substituent which may substitute the hydrogen atom of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by ^RB3 and ^RB4 is 1 of 1 to 20 of substituted or unsubstituted carbon atoms. Hydrocarbon groups of valence, -OSO _2- R ^k , -SO _2- R ^k , -OR ^k , -COOR ^k , -O-CO-R ^k , -OR ^kk- COOR ^k , -R ^kk- CO -R ^k or -S-R ^k is preferable. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

R ^B5 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, −OSO _2- R ^k , −SO _2- R ^k , −OR ^k , −COOR ^k , −O—CO−. R ^k , -OR ^kk- COOR ^k , -R ^kk- CO-R ^k or -SR ^k are preferred. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

In the above equation (rb), b4 is an integer from 0 to 9. When b4 is 1, ^RB6 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group or a halogen atom. When b4 is 2 or more, the plurality of ^RB6s are the same or different from each other and are monovalent organic groups having 1 to 20 carbon atoms, hydroxy groups, nitro groups or halogen atoms, or these groups are combined with each other. It represents a part of a ring structure having 4 to 20 ring members, which is composed of a carbon chain to which these are bonded. b5 is an integer from 0 to 10. When b5 is 1, ^RB7 is a monovalent organic group, a hydroxy group, a nitro group or a halogen atom having 1 to 20 carbon atoms. When b5 is 2 or more, the plurality of ^RB7s are the same or different from each other and are monovalent organic groups having 1 to 20 carbon atoms, hydroxy groups, nitro groups or halogen atoms, or these groups are combined with each other. It represents a part of a ring structure having 3 to 20 ring members, which is composed of a carbon atom or a carbon chain to which these are bonded. n _b2 is an integer from 0 to 3. ^RB8 is a single bond or a divalent organic group having 1 to 20 carbon atoms. n _b1 is an integer of 0 to 2.

As the ^{R B6} and ^{R B7,} 1 monovalent hydrocarbon group substituted or unsubstituted C ^{1~20, -OR k, -COOR k,} -O-CO-R k, -O-R kk -COOR ^k or −R ^kk −CO—R ^k is preferred. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

In the above equation (rc), b6 is an integer from 0 to 5. When b6 is 1, ^RB9 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group or a halogen atom. When b6 is 2 or more, the plurality of ^RB9s are the same or different from each other and are monovalent organic groups having 1 to 20 carbon atoms, hydroxy groups, nitro groups or halogen atoms, or these groups are combined with each other. It represents a part of a ring structure having 4 to 20 ring members, which is composed of a carbon chain to which these are bonded. b7 is an integer from 0 to 5. When b7 is 1, ^RB10 is a monovalent organic group, a hydroxy group, a nitro group or a halogen atom having 1 to 20 carbon atoms. When b7 is 2 or more, the plurality of ^RB10s are the same or different from each other and are monovalent organic groups having 1 to 20 carbon atoms, hydroxy groups, nitro groups or halogen atoms, or these groups are combined with each other. It represents a part of a ring structure having 4 to 20 ring members, which is composed of a carbon chain to which these are bonded.

Examples of the ^{R B9} and ^{R B10,} 1 monovalent hydrocarbon group having 1 to 20 carbon atoms substituted or _{^{unsubstituted, -OSO 2 -R k, -SO 2}} -R k, -OR k, -COOR k, - ^{O-CO-R k, -O} -R kk -COOR k, -R kk -CO-R k, is ^{-S-R k,} or two or more are combined with each other configured ring of these groups preferable. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms represented by R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include methyl group, ethyl group, n-propyl group and n-butyl group. Linear alkyl group, i-propyl group, i-butyl group, sec-butyl group, t-butyl group and other branched alkyl groups, phenyl group, trill group, xsilyl group, mesityl group, naphthyl group, etc. Examples thereof include an aryl group such as an aryl group, a benzyl group, and a phenethyl group.

As the divalent organic group represented by R ^B8 , for example, one hydrogen from a monovalent organic group having 1 to 20 carbon atoms exemplified as R ^B3 , R ^B4 and R ^B5 of the above formula (ra). Examples include groups excluding atoms.

Said ^{R B5,} as the ^{R B6,} R B7, R ^B9 and ^{R B10} represented by carbonization substituted optionally may substituent hydrogen atoms hydrogen group has, for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom Halogen atoms such as, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group and the like can be mentioned. Of these, a halogen atom is preferable, and a fluorine atom is more preferable.

R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include an unsubstituted linear or branched monovalent alkyl group, a monovalent fluorinated alkyl group, and an unsubstituted monovalent aromatic hydrocarbon. A hydrogen group, −OSO _2- R ^k or −SO _2- R ^k is preferred, a fluorinated alkyl group or an unsubstituted monovalent aromatic hydrocarbon group is more preferred, and a fluorinated alkyl group is even more preferred.

As b3 in the formula (ra), 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable. As n _bb , 0 or 1 is preferable, and 0 is more preferable. As b4 in the formula (rb), 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable. The b5 is preferably 0 to 2, more preferably 0 or 1, and even more preferably 0. As n _b2 , 2 or 3 is preferable, and 2 is more preferable. As n _b1 , 0 or 1 is preferable, and 0 is more preferable. The b6 and b7 in the formula (rc) are preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

Among these, as T ⁺ , a cation (ra) is preferable, and a triphenylsulfonium cation is more preferable.

[B] As the acid generator, as an acid generator that generates sulfonic acid, for example, compounds represented by the following formulas (5-1) to (5-5) (hereinafter, "Compounds (5-1) to (5-5)". 5-5) ”) and the like.

In the above formulas (5-1) to (5-5), T ⁺ is a monovalent radiation-sensitive onium cation.

When the [B] acid generator is a [B] acid generator, the lower limit of the content of the [B] acid generator in the radiation-sensitive resin composition is 100 parts by mass of the [A] polymer. , 0.1 part by mass is preferable, 1 part by mass is more preferable, and 5 parts by mass is further preferable. The upper limit of the content is preferably 70 parts by mass, more preferably 50 parts by mass, further preferably 40 parts by mass, and particularly preferably 30 parts by mass. [B] By setting the content of the acid generator in the above range, the sensitivity and LWR performance of the resist pattern formed by the radiation-sensitive resin composition to exposure light can be further improved, and the process window can be opened. It can be further expanded.

<[C] compound>
The compound [C] is a compound represented by the following formula (2). The compound [C] acts as an acid diffusion control agent. The acid diffusion control agent has the effect of controlling the diffusion phenomenon of the acid generated from the [B] acid generator or the like in the resist film by exposure and controlling an unfavorable chemical reaction in the non-exposed region. By containing the [C] compound, the radiation-sensitive resin composition can form a resist pattern having good sensitivity to exposure light, excellent LWR performance, and a wide process window.

In the above formula (2), R ⁷ , R ⁸ and R ⁹ are independently hydrogen atoms, fluorine atoms or monovalent organic groups having 1 to 40 carbon atoms, or among these groups. It is part of a ring structure having 3 to 20 ring members, in which two or more are combined with each other and composed of carbon atoms to which they are bonded. A ⁺ is a monovalent radiation-sensitive onium cation.

Examples of the monovalent organic group having 1 to 40 carbon atoms represented by R ⁷ , R ⁸ and R ⁹ include a group similar to the monovalent organic group exemplified as R ^{12 in the} above formula (3). Be done.

A ring structure having 3 to 20 ring members, in which two or more of R ⁷ , R ⁸ and R ⁹ are combined with each other and composed of carbon atoms to which they are bonded, is, for example, an alicyclic structure having 3 to 20 ring members. Examples thereof include an aliphatic heterocyclic structure having 4 to 20 ring members, an aromatic carbocyclic structure having 6 to 20 ring members, and an aromatic heterocyclic structure having 6 to 20 ring members.

Examples of the alicyclic structure having 3 to 20 ring members, the aliphatic heterocyclic structure having 4 to 20 ring members, the aromatic carbocyclic structure having 6 to 20 ring members, and the aromatic heterocyclic structure having 6 to 20 ring members are described above. Examples of R ^p1 of the formula (5) include an aliphatic heterocyclic structure, an aliphatic heterocyclic structure, an aromatic carbocyclic structure, and a ring structure similar to the aromatic heterocyclic structure.

Examples of the monovalent radiation-sensitive onium cation represented by A ⁺ include the monovalent radiation-sensitive onium cation exemplified as T ^{+ in the} above formula (5).

As R ⁷ , R ⁸ and R ⁹ , it is preferable that at least one of them is a fluorine atom, more preferably two of them are fluorine atoms, and R ⁷ and R ⁹ are fluorine atoms. Is even more preferable.

The R ^8, preferably a monovalent organic group having 1 to 40 carbon atoms. Among them, a monovalent organic group having 1 to 40 carbon atoms containing a hetero atom other than a fluorine atom is more preferable. Examples of the hetero atom other than the fluorine atom include a nitrogen atom, an oxygen atom and a sulfur atom, and an oxygen atom is preferable. It is more preferable that R ⁸ is a monovalent organic group having 1 to 40 carbon atoms containing at least one selected from an ester structure, a ketone structure and a hydroxyl group. Further, it is also preferable that R ⁸ is a monovalent organic group having a ring structure and having 1 to 40 carbon atoms. Examples of such a ring structure include an alicyclic structure, an aromatic carbocyclic structure, an aliphatic heterocyclic structure, and an aromatic heterocyclic structure, and the specific ring structure is the same as described above. Among them, the alicyclic structure is preferable as the ring structure, and the cycloalkyl ring and the adamantane ring are more preferable. Alternatively, R ⁸ is preferably a monovalent organic group having 1 to 40 carbon atoms and does not contain a fluorine atom. It is particularly preferable that R ⁷ and R ⁹ are fluorine atoms and R ⁸ is in such an embodiment.

As A ⁺ , the above cation (ra), the above cation formula (rb) or the above cation (rc) is preferable, and the above cation (ra) or the above cation (rb) is more preferable. , The above cation (ra) is more preferable, and the triphenylsulfonium cation is particularly preferable.

Examples of the [C] compound include compounds represented by the following formulas (2-1) to (2-15) (hereinafter, also referred to as "compounds (2-1) to (2-15)"). ..

In the above formulas (2-1) to (2-15), A ⁺ has the same meaning as the above formula (2).

As the [C] compound, the above compounds (2-1) to (2-7) are preferable.

The lower limit of the content ratio of the [C] compound in the radiation-sensitive resin composition is preferably 1 mol%, more preferably 5 mol%, and 10 mol% with respect to 100 mol% of the [B] acid generator. More preferred. The upper limit of the content ratio is preferably 200 mol%, more preferably 10 mol%, still more preferably 50 mol%. By setting the content ratio of the [C] compound in the above range, the sensitivity and LWR performance of the resist pattern formed by the radiation-sensitive resin composition to exposure light can be further improved, and the process window can be further expanded. be able to.

<[D] Organic solvent>
The radiation-sensitive resin composition usually contains [D] an organic solvent. The [D] organic solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the [A] polymer, the [B] acid generator, the [C] compound and any component contained if desired.

[D] Examples of the organic solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents and the like.

Examples of the alcohol solvent include an aliphatic monoalcohol solvent having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol, and an alicyclic monoalcohol solvent having 3 to 18 carbon atoms such as cyclohexanol. Examples thereof include a solvent, a polyhydric alcohol solvent having 2 to 18 carbon atoms such as 1,2-propylene glycol, and a polyhydric alcohol partial ether solvent having 3 to 19 carbon atoms such as propylene glycol-1-monomethyl ether.

Examples of the ether-based solvent include dialkyl ether-based solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether and diheptyl ether, cyclic ether-based solvents such as tetrahydrofuran and tetrahydropyran, and diphenyl ethers. Examples thereof include an aromatic ring-containing ether-based solvent such as anisole.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, and the like. Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanone, cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone, 2,4-pentandione and acetonylacetone. , Acetphenone and the like.

Examples of the amide solvent include cyclic amide solvents such as N, N'-dimethylimidazolidinone and N-methylpyrrolidone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, and N. Examples thereof include chain amide solvents such as −methylacetamide, N, N-dimethylacetamide and N-methylpropionamide.

Examples of the ester solvent include a monocarboxylic acid ester solvent such as n-butyl acetate and ethyl lactate, a lactone solvent such as γ-butyrolactone and valerolactone, a polyhydric alcohol carboxylate solvent such as propylene glycol acetate, and propylene acetate. Examples thereof include a polyhydric alcohol partial ether carboxylate solvent such as glycol monomethyl ether, a polycarboxylic acid diester solvent such as diethyl oxalate, and a carbonate solvent such as dimethyl carbonate and diethyl carbonate.

Examples of the hydrocarbon solvent include an aliphatic hydrocarbon solvent having 5 to 12 carbon atoms such as n-pentane and n-hexane, and an aromatic hydrocarbon solvent having 6 to 16 carbon atoms such as toluene and xylene. Be done.

[D] As the organic solvent, an alcohol solvent or an ester solvent is preferable, a polyhydric alcohol partial ether solvent having 3 to 19 carbon atoms or a polyhydric alcohol partial ether carboxylate solvent is more preferable, and propylene glycol-1- More preferably, monomethyl ether or propylene glycol monomethyl ether acetate. [D] The organic solvent may contain one kind or two or more kinds.

When the radiation-sensitive resin composition contains the [D] organic solvent, the lower limit of the content ratio of the [D] organic solvent is 50% by mass with respect to all the components contained in the radiation-sensitive resin composition. % Is preferable, 60% by mass is more preferable, 70% by mass is further preferable, and 80% by mass is particularly preferable. The upper limit of the content ratio is preferably 99.9% by mass, preferably 99.5% by mass, and even more preferably 99.0% by mass.

<Other optional ingredients>
Examples of other optional components include acid diffusion controllers other than the [C] compound, surfactants, and the like. The radiation-sensitive resin composition may contain one or more other optional components, respectively.

[Acid diffusion control bodies other than [C] compound]
Examples of the contained form of the acid diffusion control body other than the [C] compound in the radiation-sensitive resin composition include the form of a low molecular weight compound (hereinafter, also referred to as “another acid diffusion control agent”) and [A] heavy weight. Examples include forms incorporated as part of a polymer such as coalescing, or both forms.

Examples of other acid diffusion control agents include nitrogen atom-containing compounds, photodisintegrating bases that are exposed to exposure to generate weak acids (excluding those corresponding to the [C] compound), and the like.

Examples of the nitrogen atom-containing compound include amine compounds such as trypentylamine and trioctylamine, amide group-containing compounds such as formamide and N, N-dimethylacetamide, urea compounds such as urea and 1,1-dimethylurea, and pyridine. Examples thereof include nitrogen-containing heterocyclic compounds such as N- (undecylcarbonyloxyethyl) morpholine and Nt-pentyloxycarbonyl-4-hydroxypiperidin.

Examples of the photodisintegrating base include compounds containing an onium cation and a weak acid anion that are decomposed by exposure (excluding those corresponding to the [C] compound).

When the radiation-sensitive resin composition contains another acid diffusion control agent, the lower limit of the content ratio of the other acid diffusion control agent in the radiation-sensitive resin composition is [B] 100 mol% of the acid generator. On the other hand, 1 mol% is preferable, 5 mol% is more preferable, and 10 mol% is further preferable. The upper limit of the content ratio is preferably 200 mol%, more preferably 100 mol%, still more preferably 50 mol%.

[Surfactant]
Surfactants have the effect of improving coatability, striation, developability and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol di. Nonionic surfactants such as stearate can be mentioned. Commercially available products include KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, No. 95 (above, Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (above, Tochem Products Co., Ltd.), Megafuck F171, F173 (above, DIC Corporation), Florard FC430, same FC431 (Sumitomo 3M Ltd.), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( As mentioned above, Asahi Glass Industry Co., Ltd. and the like can be mentioned.

When the radiation-sensitive resin composition contains a surfactant, the upper limit of the content of the surfactant in the radiation-sensitive resin composition is 2 parts by mass with respect to 100 parts by mass of the polymer [A]. Is preferable. The lower limit of the content is, for example, 0.1 parts by mass.

<Method for preparing radiation-sensitive resin composition>
The radiation-sensitive resin composition is, for example, a mixture of [A] polymer, [B] acid generator, [C] compound and, if necessary, [D] organic solvent and other optional components in a predetermined ratio. However, it can be preferably prepared by filtering the obtained mixture with a polymer filter having a pore size of 0.2 μm or less.

The radiation-sensitive resin composition can be used for forming a positive pattern using an alkaline developer and for forming a negative pattern using an organic solvent-containing developer.

The radiation-sensitive resin composition is for exposure with radiation (exposure light) irradiated in the exposure step in the resist pattern forming method described later. Extreme ultraviolet (EUV) or electron beam has a relatively high energy among the exposure light, but according to the radiation-sensitive resin composition, exposure even when extreme ultraviolet or electron beam is used as the exposure light. It has good sensitivity to light, has excellent LWR performance, and can form a resist pattern with a wide process window. Therefore, the radiation-sensitive resin composition can be particularly preferably used for extreme ultraviolet exposure or electron beam exposure.

<Resist pattern formation method>
The resist pattern forming method includes a step of directly or indirectly coating the radiation-sensitive resin composition on a substrate (hereinafter, also referred to as a “coating step”) and exposing a resist film formed by the coating step. A step of developing the exposed resist film (hereinafter, also referred to as “exposure step”) and a step of developing the exposed resist film (hereinafter, also referred to as “development step”) are provided.

According to the resist pattern forming method, by using the radiation-sensitive resin composition in the coating process, a resist pattern having good sensitivity to exposure light, excellent LWR performance, and a wide process window can be formed. Can be done.

Hereinafter, each step included in the resist pattern forming method will be described.

[Coating process]
In this step, the radiation-sensitive resin composition is directly or indirectly applied to the substrate. As a result, a resist film is formed. Examples of the substrate include conventionally known wafers such as silicon wafers, silicon dioxide, and wafers coated with aluminum. Further, as the underlayer film, for example, an organic or inorganic antireflection film disclosed in Japanese Patent Application Laid-Open No. 6-12452 and JP-A-59-93448 may be formed on the substrate. Examples of the coating method include rotary coating (spin coating), cast coating, roll coating and the like. After coating, if necessary, prebaking (PB) may be performed to volatilize the solvent in the coating film. As the lower limit of the temperature of PB, 60 ° C. is preferable, and 80 ° C. is more preferable. The upper limit of the temperature is preferably 150 ° C., more preferably 140 ° C. As the lower limit of the PB time, 5 seconds is preferable, and 10 seconds is more preferable. As the lower limit of the time, 600 seconds is preferable, and 300 seconds is more preferable. The lower limit of the average thickness of the resist film formed is preferably 10 nm, more preferably 20 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm.

[Exposure process]
In this step, the resist film formed by the above coating step is exposed. This exposure is performed by irradiating the exposure light through a photomask (in some cases, through an immersion medium such as water). The exposure light includes electromagnetic waves such as visible light, ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), X-rays, and γ-rays; charged particles such as electron beams and α-rays, depending on the line width of the target pattern. Examples include lines. Among these, far ultraviolet rays, EUV or electron beams are preferable, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), EUV or electron beams are more preferable, and ArF excimer laser light, EUV or electron beams are preferable. More preferably, EUV or electron beam is particularly preferable. The exposure conditions such as the exposure amount can be appropriately selected according to the compounding composition of the radiation-sensitive resin composition, the type of additive, the type of exposure light, and the like.

After the above exposure, post-exposure baking (PEB) is performed, and in the exposed portion of the resist film, the acid dissociative group of the [A] polymer is dissociated by the acid generated from the [B] acid generator or the like by the exposure. It is preferable to promote. With this PEB, it is possible to increase the difference in solubility in the developing solution between the exposed portion and the unexposed portion. As the lower limit of the temperature of PEB, 50 ° C. is preferable, 80 ° C. is more preferable, and 90 ° C. is further preferable. The upper limit of the temperature is preferably 180 ° C., more preferably 130 ° C. As the lower limit of the PEB time, 5 seconds is preferable, 10 seconds is more preferable, and 30 seconds is further preferable. The upper limit of the time is preferably 600 seconds, more preferably 300 seconds, and even more preferably 100 seconds.

[Development process]
In this step, the exposed resist film is developed. As a result, a predetermined resist pattern can be formed. After development, it is generally washed with a rinse solution such as water or alcohol and dried. The developing method in the developing step may be alkaline development or organic solvent development.

In the case of alkaline development, the developing solution used for development includes, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-. Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1 , 5-Diazabicyclo- [4.3.0] -5-Nonene and other alkaline compounds dissolved in at least one alkaline aqueous solution. Among these, the TMAH aqueous solution is preferable, and the 2.38 mass% TMAH aqueous solution is more preferable.

In the case of organic solvent development, examples of the developing solution include organic solvents such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents and alcohol solvents, and solvents containing the above organic solvents. Examples of the organic solvent include one or more of the solvents exemplified as the [D] organic solvent of the above-mentioned radiation-sensitive resin composition. Among these, an ester solvent or a ketone solvent is preferable. As the ester solvent, an acetic acid ester solvent is preferable, and n-butyl acetate is more preferable. As the ketone solvent, a chain ketone is preferable, and 2-heptanone is more preferable. The lower limit of the content of the organic solvent in the developing solution is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, and particularly preferably 99% by mass. Examples of the components other than the organic solvent in the developing solution include water, silicone oil and the like.

Examples of the developing method include a method of immersing the substrate in a tank filled with a developing solution for a certain period of time (dip method), and a method of developing by raising the developing solution on the surface of the substrate by surface tension and allowing it to stand still for a certain period of time (paddle method). ), A method of spraying the developer on the surface of the substrate (spray method), a method of continuing to apply the developer on the substrate rotating at a constant speed while scanning the developer dispensing nozzle at a constant speed (dynamic discharge method). And so on.

Examples of the pattern formed by the resist pattern forming method include a line-and-space pattern and a hole pattern.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The measurement method of various physical property values is shown below.

[Weight average molecular weight (Mw), number average molecular weight (Mn) and dispersity (Mw / Mn)]
For the Mw and Mn of the polymer, a GPC column (2 "G2000HXL", 1 "G3000HXL", and 1 "G4000HXL") of Tosoh Corporation was used by gel permeation chromatography (GPC). It was measured according to the conditions of. The dispersity (Mw / Mn) was calculated from the measurement results of Mw and Mn.

Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Column temperature: 40 ° C
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[Content ratio of each structural unit of polymer]
The content ratio of each structural unit of the polymer was determined by ¹³ C-NMR analysis using a nuclear magnetic resonance apparatus (“JNM-Delta 400” of JEOL Ltd.).

<[A] Synthesis of polymer>
The monomers used in the synthesis of each polymer in each Example and Comparative Example are shown below. In the following synthesis examples, unless otherwise specified, parts by mass mean a value when the total mass of the monomers used is 100 parts by mass, and mol% is the total number of moles of the monomers used. Means the value when is 100 mol%.

[Synthesis Example 1] Synthesis of Polymer (A-1) Monomer (M-1), Monomer (M-3) and Monomer (M-10) in molar ratio of 40/40/20 ( It was dissolved in propylene glycol-1-monomethyl ether (200 parts by mass) so as to have a molar%), and AIBN (6 mol%) was added as an initiator to prepare a monomer solution. Propylene glycol-1-monomethyl ether (100 parts by mass) was placed in an empty reaction vessel and heated to 85 ° C. with stirring. Next, the monomer solution was added dropwise to the reaction vessel over 3 hours, and the mixture was further heated at 85 ° C. for 3 hours. The polymerization reaction was carried out for a total of 6 hours with the start of the dropping of the monomer solution as the start time of the polymerization reaction. Carried out. After completion of the polymerization reaction, the polymerization solution was cooled to room temperature. The cooled polymerization solution was put into hexane (500 parts by mass with respect to 100 parts by mass of the polymerization solution), and the precipitated white powder was filtered off. The filtered white powder was washed twice with hexane (100 parts by mass with respect to 100 parts by mass of the polymerization solution), filtered, and dissolved in propylene glycol-1-monomethyl ether (300 parts by mass). Next, methanol (500 parts by mass), triethylamine (50 parts by mass) and ultrapure water (10 parts by mass) were added, and a hydrolysis reaction was carried out at 70 ° C. for 6 hours with stirring. After completion of the hydrolysis reaction, the residual solvent was distilled off, and the obtained solid was dissolved in acetone (100 parts by mass). This solution was added dropwise to 500 parts by mass of water to solidify the resin, the obtained solid was filtered off, and dried at 50 ° C. for 12 hours to obtain a white powdery polymer (A-1). The Mw of the polymer (A-1) was 5600, and the Mw / Mn was 1.62. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from (M-1), (M-3) and (M-10) were 42.3 mol%, 39.8 mol% and 39.8 mol%, respectively. It was 17.9 mol%.

[Synthesis Examples 2 to 8] Synthesis of Polymers (A-2) to (A-8) The weight is the same as that of Synthesis Example 1 except that the monomers of the types and blending ratios shown in Table 1 below are used. Combined (A-2) to (A-8) were synthesized. The content ratio and physical property values (Mw and Mw / Mn) of each structural unit of the obtained polymer are shown in Table 1 below. In addition, "-" in Table 1 below indicates that the corresponding monomer was not used.

[Synthesis Example 9] Synthesis of Polymer (A-9) “Polymer (B-3-1)” described in JP-A-2009-244805, using the monomers of the types and blending ratios shown in Table 1 below. The polymer (A-9) was synthesized by the same method as the synthesis method of. The content ratio and physical property values (Mw and Mw / Mn) of each structural unit of the obtained polymer are shown in Table 1 below.

<Preparation of radiation-sensitive resin composition>
The components other than the [A] polymer used for preparing the radiation-sensitive resin composition are shown below. In the following Examples and Comparative Examples, unless otherwise specified, parts by mass mean a value when the mass of the polymer used is 100 parts by mass, and mol% means the used [B] acid generator. It means a value when the number of moles of is 100 mol%.

[[B] Acid generator]
B-1 to B-4: Compounds represented by the following formulas (B-1) to (B-4)

[[C] Acid diffusion control agent]
C-1 to C-9: Compounds represented by the following formulas (C-1) to (C-9)

[[D] Organic solvent]
D-1: Propylene glycol monomethyl ether acetate D-2: Propylene glycol-1-monomethyl ether

[Example 1]
[A] 100 parts by mass of (A-1) as a polymer, 20 parts by mass of (B-1) as an acid generator, and 20 mol of (C-1) as an [C] acid diffusion control agent. %, [D] 4800 parts by mass of (D-1) and 2000 parts by mass of (D-2) as an organic solvent are mixed and filtered through a polymer filter having a pore size of 0.2 μm to obtain a radiation-sensitive resin composition ( R-1) was prepared.

[Examples 2 to 14 and Comparative Examples 1 to 3]
Radiation-sensitive resin compositions (R-2) to (R-14) and (CR-1) to the same as in Example 1 except that each component of the type and content shown in Table 2 below was used. (CR-3) was prepared.

<Formation of resist pattern (EUV exposure, alkaline development)>
The above-prepared radiation-sensitive resin composition was applied to the underlayer film of a 12-inch silicon wafer on which an underlayer film with an average thickness of 20 nm (“AL412” from Brewer Science Co., Ltd.) was formed. It was applied using CLEAN TRACK ACT12 ”) and soft-baked (SB) was performed at 130 ° C. for 60 seconds. Then, by cooling at 23 ° C. for 30 seconds, a resist film having an average thickness of 50 nm was formed. Next, this resist film was exposed to this resist film using an EUV exposure apparatus (“NEX3300” manufactured by ASML) with NA = 0.33, illumination conditions: Conventional s = 0.89, and mask: imageDEFECT32FFR02. After the exposure, a 2.38 mass% TMAH solution was used as an alkaline developer and developed at 23 ° C. for 30 seconds to form a positive resist pattern (32 nm line and space pattern).

<Evaluation>
The sensitivity, LWR performance and process window of the formed resist pattern were evaluated according to the following methods. A scanning electron microscope (“CG-4100” of Hitachi High-Tech Technology Corporation) was used to measure the length of the resist pattern. The evaluation results are shown in Table 3 below. In addition, "-" in Table 3 below indicates that in Comparative Example 2, even the unexposed portion was dissolved in the alkaline developer, so that the resist pattern was not formed and various evaluations could not be performed.

[sensitivity]
In the formation of the resist pattern, the exposure amount for forming the 32 nm line-and-space pattern was defined as the optimum exposure amount, and this optimum exposure amount was defined as the sensitivity (mJ / cm ² ). The sensitivity can be evaluated as "good" when it is 30 mJ / cm ² or less, and as "poor" when it exceeds 30 mJ / cm ² .

[LWR performance]
The resist pattern formed above was observed from above the register pattern using the scanning electron microscope. A total of 50 points of line width were measured at arbitrary points, 3 sigma values were obtained from the distribution of the measured values, and these 3 sigma values were defined as LWR (nm). The LWR indicates that the smaller the value, the smaller the rattling of the line and the better. The LWR performance can be evaluated as "good" when it is 4.0 nm or less and "bad" when it exceeds 4.0 nm.

[Process window]
"Process window" means the range of resist dimensions that can form a pattern that is free of bridge defects and tilt. Using a mask to form a 32 nm line-and-space pattern (1L / 1S), patterns from low to high exposures were formed. Generally, in the case of low exposure, defects such as bridge formation between patterns are observed, and in the case of high exposure, defects such as pattern collapse are observed. The difference between the maximum value and the minimum value of the resist dimensions in which these defects are not observed is defined as a "CD (Critical Demension) margin". The larger the value of the CD margin, the wider the process window and the better. When the CD margin is 30 nm or more, it can be evaluated as “good”, and when it is less than 30 nm, it can be evaluated as “bad”.

As is clear from the results in Table 3, the radiation-sensitive resin compositions of Examples were superior in sensitivity, LWR performance, and CD margin as compared with the radiation-sensitive resin compositions of Comparative Examples.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, it is possible to form a resist pattern having good sensitivity to exposure light, excellent LWR performance, and a wide process window. Therefore, these can be suitably used for processing processes of semiconductor devices, which are expected to be further miniaturized in the future.

Claims (8)

A polymer having a first structural unit containing a phenolic hydroxyl group, a second structural unit containing a group represented by the following formula (1), and a third structural unit containing an acid dissociable group,
Radiation-sensitive acid generators and
A radiation-sensitive resin composition containing a compound represented by the following formula (2).

(In formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are independently hydrogen atoms, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms or 1 to 1 carbon atoms. It is a monovalent fluorinated hydrocarbon group of 10. However, at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is a fluorine atom or a fluorinated hydrocarbon group. ^RA is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. * Indicates a bonding site with a portion other than the group represented by the above formula (1) in the above second structural unit. )

(In the formula (2), R ⁷ , R ⁸ and R ⁹ are independently hydrogen atoms, fluorine atoms or monovalent organic groups having 1 to 40 carbon atoms, or among these groups. It is a part of a ring structure having 3 to 20 ring members, in which two or more are combined with each other and composed of carbon atoms to which they are bonded. A ⁺ is a monovalent radiosensitive onium cation.) The radiation-sensitive resin composition according to claim 1, wherein at least one of R ⁷ , R ⁸ and R ⁹ in the above formula (2) is a fluorine atom. R ⁷ and R ⁹ in the above formula (2) are fluorine atoms.
A monovalent organic group having 1 to 40 carbon atoms R ⁸ contains a heteroatom other than a fluorine atom, an ester structure, a monovalent organic group having 1 to 40 carbon atoms containing at least one selected from the ketone structure and a hydroxyl group, The radiation-sensitive resin composition according to claim 2, which is a monovalent organic group having 1 to 40 carbon atoms and does not contain a fluorine atom. The radiation-sensitive resin composition according to claim 1, wherein the content ratio of the third structural unit in the polymer is 30 mol% or more and 80 mol% or less with respect to all the structural units constituting the polymer. The radiation-sensitive resin composition according to claim 1, wherein the first structural unit is represented by the following formula (3).

(In formula (3), R ¹⁰ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹¹ is a single bond, −O−, −COO− or −CONH−. Ar is , A group having 6 to 20 ring members minus (p + q + 1) hydrogen atoms on the aromatic ring. P is an integer of 0 to 10. When p is 1, R ¹² is the number of carbon atoms. It is a monovalent organic group or halogen atom of 1 to 20. When p is 2 or more, the plurality of R ^12s are the same or different from each other, and are monovalent organic groups or halogen atoms having 1 to 20 carbon atoms. or two or more are combined with each other is part of the ring structure formed ring members 4-20 together with the carbon chain to which they are attached .q of the plurality of R ¹² is an integer of 1 to 11. However, p + q is 11 or less.) The third structural unit according to claim 1, wherein the third structural unit is represented by the following formula (4-1A), formula (4-1B), formula (4-1C), formula (4-2A) or formula (4-2B). Radiation-sensitive resin composition.

(In formulas (4-1A), (4-1B), (4-1C), (4-2A) and (4-2B), ^RT is independently a hydrogen atom, a fluorine atom and a methyl group. Alternatively, it is a trifluoromethyl group.
Wherein (4-1A) and (4-1B), ^{R X} is independently a monovalent hydrocarbon group having a hydrogen atom or a C 1-20. Each of ^RY and R ^Z is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a ring formed by combining ^RY and R ^Z with carbon atoms to which they are bonded. It is a part of the alicyclic structure having 3 to 20 members.
In formula (4-1C), ^RC is a hydrogen atom. R ^D and ^{R E} are each independently a monovalent hydrocarbon group having a hydrogen atom or a C 1-20. R ^F is ^a divalent hydrocarbon group R C, carbon atoms constituting the unsaturated alicyclic structure ring members 4 to 20 together with the carbon atom ^{to which R D} and ^{R E} are respectively coupled to 20.
Wherein (4-2A) and (4-2B), ^{R U} and ^{R V} are each independently a monovalent hydrocarbon group having a hydrogen atom or a carbon number of 1 to 20, ^{R W} are each independently to either a monovalent hydrocarbon group having 1 to 20 carbon atoms, a part of the alicyclic structure formed ring members 3 to 20 together with the carbon atom to which R ^U and R ^V are combined they are bound to each other or it is, or is part of R ^U and R ^W aliphatic heterocyclic structure consisting ring members 5 to 20 together with the oxygen atom is bonded carbon atoms and R ^W that keyed R ^U, bonded to each other. ) The radiation-sensitive resin composition according to claim 1, which is for extreme ultraviolet exposure or electron beam exposure. The process of directly or indirectly applying the radiation-sensitive resin composition to the substrate,
The process of exposing the resist film formed by the above coating process and
The process of developing the resist film after the above exposure step is provided.
The radiation-sensitive resin composition is
A polymer having a first structural unit containing a phenolic hydroxyl group, a second structural unit containing a group represented by the following formula (1), and a third structural unit containing an acid dissociable group,
Radiation-sensitive acid generators and
A resist pattern forming method containing a compound represented by the following formula (2).

(In formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are independently hydrogen atoms, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms or 1 to 1 carbon atoms. It is a monovalent fluorinated hydrocarbon group of 10. However, at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is a fluorine atom or a fluorinated hydrocarbon group. ^RA is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. * Indicates a bonding site with a portion other than the group represented by the above formula (1) in the above second structural unit. )

(In the formula (2), R ⁷ , R ⁸ and R ⁹ are independently hydrogen atoms, fluorine atoms or monovalent organic groups having 1 to 40 carbon atoms, or among these groups. It is a part of a ring structure having 3 to 20 ring members, in which two or more are combined with each other and composed of carbon atoms to which they are bonded. A ⁺ is a monovalent radiosensitive onium cation.)