WO2017057203A1

WO2017057203A1 - Radiation sensitive resin composition and resist pattern forming method

Info

Publication number: WO2017057203A1
Application number: PCT/JP2016/078130
Authority: WO
Inventors: 拡宮田
Original assignee: Jsr株式会社
Priority date: 2015-09-29
Filing date: 2016-09-23
Publication date: 2017-04-06
Also published as: TW201715311A

Abstract

The present invention is a radiation sensitive resin composition which contains: a polymer having a first structural unit that contains an acid-cleavable group and an oxo acid group or phenolic hydroxyl group that is protected by the acid-cleavable group; and a radiation sensitive acid generator represented by formula (b). This radiation sensitive resin composition is characterized in that the acid-cleavable group is represented by formula (1). In formula (1), Ar represents a (m + n + 1)-valent group derived from an aromatic ring having 6-30 carbon atoms; R¹ represents a divalent organic group having 3-20 carbon atoms; R² represents a halogen atom or a monovalent organic group having 1-20 carbon atoms; and m represents an integer of 1-13 and n represents an integer of 0-13, provided that (m + n) is 13 or less. In formula (b), R^p1 represents a monovalent group containing a ring structure having 6 or more ring members; and X⁺ represents a monovalent radiation sensitive onium cation.

Description

Radiation-sensitive resin composition and resist pattern forming method

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

The chemically amplified radiation-sensitive resin composition generates an acid from an acid generator at an exposed portion by irradiation with exposure light such as ArF excimer laser light and KrF excimer laser light, and the reaction is carried out by reaction using this acid as a catalyst. The dissolution rate of the part and the unexposed part in the developer is changed to form a resist pattern on the substrate.

Such a radiation-sensitive resin composition is required to have excellent lithography performance such as sensitivity and resolution as processing technology becomes finer. In response to this requirement, various structures of acid-dissociable groups possessed by the polymer in the radiation-sensitive resin composition have been studied, and those having a plurality of specific ring structures are known (Japanese Patent Laid-Open No. 2011-43794). reference). According to this radiation sensitive resin composition, it is said that resolution can be improved.

However, at present, when the miniaturization of resist patterns is progressing to a level of 40 nm or less, the radiation-sensitive resin composition is required to have excellent sensitivity, and the line width varies. It is required to be superior to LWR (Line Width Roughness) performance. In particular, recently, since the resist film has been made thinner with the progress of pattern miniaturization, it is strongly desired to improve the reduction of film thickness.

JP 2011-43794 A

The present invention has been made on the basis of the circumstances as described above, and its purpose is to provide a radiation-sensitive resin composition and a resist pattern forming method that are excellent in LWR performance and film reduction inhibition while maintaining excellent sensitivity. It is to provide.

The invention made in order to solve the above-mentioned problem is a first structural unit containing an acid dissociable group and an oxo acid group or a phenolic hydroxyl group protected by this acid dissociable group (hereinafter referred to as “structural unit (I)”). And a radiation-sensitive acid generator represented by the following formula (b), wherein the acid-dissociable group is represented by the following formula (1): It is represented by.

(In the formula (1), Ar is a (m + n + 1) -valent group derived from an aromatic ring having 6 to 30 carbon atoms. R ¹ is a divalent organic group having 3 to 20 carbon atoms. R ² Is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, m is an integer of 1 to 13, n is an integer of 0 to 13, provided that m + n is 13 or less. When n is 2 or more, the plurality of R ² may be the same or different. * Indicates the binding site to the oxy group in the protected oxo acid group or phenolic hydroxyl group.)

(In formula (b), R ^p1 is a monovalent group containing a ring structure having 6 or more ring members. R ^p2 is a divalent linking group. R ^p3 and R ^p4 are each independently , A hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, wherein R ^p5 and R ^p6 are each independently fluorine An atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, n ^p1 is an integer of 0 to 10. n ^p2 is an integer of 0 to 10. n ^p3 is 1 to 10 When n ^p1 is 2 or more, the plurality of R ^p2 may be the same or different, and when n ^p2 is 2 or more, the plurality of R ^p3 may be the same or different, and a plurality of R ^p2 ^p4 may be the same or different, and when n ^p3 is 2 or more, a plurality of R ^p5 may be the same or different. And a plurality of R ^p6 may be the same or different. X ⁺ is a monovalent radiation-sensitive onium cation.)

Another invention made to solve the above problems comprises a step of forming a resist film, a step of exposing the resist film, and a step of developing the exposed resist film. It is a resist pattern formation method formed with a radiation resin composition.

Here, “organic group” means a group containing at least one carbon atom. The “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure but includes only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The term “alicyclic hydrocarbon group” refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, it is not necessary to be composed only of the alicyclic structure, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure.

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 that is excellent in LWR performance and film reduction inhibition while maintaining excellent sensitivity. Therefore, these can be suitably used for manufacturing semiconductor devices that are expected to be further miniaturized in the future.

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

The radiation-sensitive resin composition contains an [A] polymer and an [B] acid generator, so that it maintains excellent sensitivity and is excellent in LWR performance and film reduction inhibition (hereinafter referred to as these performances). Are collectively referred to as “LWR performance”). The reason why the radiation-sensitive resin composition has the above-described configuration provides the above-mentioned effect is not necessarily clear, but can be inferred as follows, for example. That is, the structural unit (I) of the [A] polymer contains an acid dissociable group, this acid dissociable group contains R ¹ and has a phenolic hydroxyl group. By having R ¹ , the hydrophobicity of the structural unit (I) is increased, so that the solubility in an alkaline developer or the like is lowered, and as a result, the film loss suppressing property is improved. [A] The polymer has a structural unit (I) in which the acid-dissociable group has a phenolic hydroxyl group, thereby increasing the content of the acid-dissociable group without reducing the content of the phenolic hydroxyl group. Therefore, dissolution contrast can be increased while maintaining excellent sensitivity, and LWR performance can be improved. In addition, because the acid generator [B] has a specific structure represented by the formula (b), an acid resist generated by exposure due to the interaction with the structural unit (I) of the polymer [A], etc. It is considered that the diffusion length in the film is appropriately shortened, and as a result, the LWR performance and the depth of focus of the radiation-sensitive resin composition are further improved. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I). [A] In addition to the structural unit (I), the polymer is a group (z) having a hydroxy group at the terminal and a carbon atom adjacent to the hydroxy group having at least one fluorine atom or fluorinated alkyl group. A structural unit other than the structural unit (II), the structural unit (I), the structural unit (III) including an acid-dissociable group, a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. (IV), which may have a structural unit (V) containing an alcoholic hydroxyl group and a structural unit (VI) containing a phenolic hydroxyl group, and other structural units other than the structural units (I) to (VI) You may have. [A] The polymer may have one or more of the above structural units. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) includes an acid dissociable group (hereinafter also referred to as “group (I)”) and an oxo acid group or a phenolic hydroxyl group (hereinafter referred to as “oxo acid group or the like”) protected by the acid dissociable group. The acid dissociable group is a structural unit represented by the following formula (1).

The “oxo acid group” refers to a group derived from an acid (oxo acid) in which a hydrogen atom capable of dissociating as a proton is bonded to an oxygen atom (oxy group). The “acid-dissociable group” refers to a group that protects an oxo acid group or the like by substituting a hydrogen atom bonded to the oxy group and dissociates by the action of an acid.

In the above formula (1), Ar is a (m + n + 1) -valent group derived from an aromatic ring having 6 to 30 carbon atoms. R ¹ is a divalent organic group having 3 to 20 carbon atoms. R ² is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. m is an integer of 1 to 13. n is an integer of 0 to 13. However, m + n is 13 or less. When n is 2 or more, the plurality of R ² may be the same or different. * Indicates the binding site to the oxy group in the protected oxo acid group or phenolic hydroxyl group.

The group (I) is an acid dissociable group. In the case where the group (I) is an acid dissociable group, for example, the carbon atom in R ¹ bonded to an oxy group such as an oxo acid group is tertiary (bonded to three carbon atoms). In some cases, a carbon atom in R ¹ bonded to an oxy group such as an oxo acid group is bonded to another oxygen atom to form an O—C—O structure. Among these, from the viewpoint that the group (I) exhibits a more appropriate acid dissociation property, it is preferable that the carbon atom in R ¹ bonded to an oxy group such as an oxo acid group is tertiary.

Ar is a (m + n + 1) -valent group derived from an aromatic ring having 6 to 30 carbon atoms. The (m + n + 1) -valent group derived from an aromatic ring refers to a group in which (m + n + 1) hydrogen atoms bonded to a carbon atom constituting the aromatic ring are removed from the aromatic ring. Examples of the aromatic ring in Ar include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a naphthacene ring, a pentacene ring, and a pyrene ring.

Examples of the oxo acid group include a carboxy group, a sulfo group, a sulfate group, and a phosphate group. Among these, a carboxy group is preferred from the viewpoint of the group (I) exhibiting a more appropriate acid dissociability and the ease of synthesis of the monomer that gives the structural unit (I).

Examples of the divalent organic group having 3 to 20 carbon atoms represented by R ¹ include, for example, a divalent hydrocarbon group having 3 to 20 carbon atoms, a carbon-carbon boundary of this hydrocarbon group, or a terminal on the bond side. And groups containing a divalent heteroatom-containing group (a), a group obtained by substituting part or all of the hydrogen atoms of the hydrocarbon group and the group (a) with a monovalent heteroatom-containing group, and the like.

Examples of the divalent hydrocarbon group having 3 to 20 carbon atoms include, for example, a divalent chain hydrocarbon group having 3 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, Examples thereof include 6 to 20 divalent aromatic hydrocarbon groups.

Examples of the divalent chain hydrocarbon group having 3 to 20 carbon atoms include alkanediyl groups such as propanediyl group, butanediyl group, pentanediyl group, hexanediyl group, heptanediyl group and octanediyl group;
Alkenediyl groups such as propenediyl group, butenediyl group, pentenediyl group, hexenediyl group, heptenediyl group, octenediyl group;
Examples thereof include alkynediyl groups such as propynediyl group, butynediyl group, pentynediyl group, hexynediyl group, heptindiyl group, and octynediyl group.

Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include cycloalkanediyl groups such as cyclopentanediyl group, cyclohexanediyl group, cycloheptanediyl group, and cyclooctanediyl group;
Polycyclic alicyclic saturated hydrocarbon groups such as norbornanediyl group and adamantanediyl group;
A cycloalkenediyl group such as a cyclopentenediyl group, a cyclohexenediyl group, a cycloheptenediyl group, a cyclooctenediyl group;
Examples thereof include polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenediyl group.

Examples of the divalent aromatic hydrocarbon group having 6 to 20 carbon atoms include arenediyl groups such as a phenylene group, a toluenediyl group, a xylenediyl group, a naphthalenediyl group, and an anthracenediyl group;
Examples thereof include arenediylalkanediyl groups such as benzenediylmethanediyl group and naphthalenediylmethanediyl group.

Examples of the divalent heteroatom-containing group include —O—, —CO—, —S—, —CS—, —NR′—, and a combination of two or more thereof. R ′ is a hydrogen atom or a monovalent hydrocarbon group. Of these, —COO— is preferable.
Examples of the monovalent heteroatom-containing group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, amino group, sulfanyl group (—SH) and the like. . Among these, a fluorine atom is preferable.

Examples of the R ^1, groups (hereinafter, also referred to as "group (X)") represented by the following formula (X) are preferred.

In the above formula (X), * represents a bonding site to the oxy group in the protected oxo acid group or phenolic hydroxyl group. ** represents a site bonded to the aromatic ring in Ar in the above formula (1). R ³ and R ⁴ are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group. R ⁵ is a single bond, an oxygen atom or a divalent hydrocarbon group. Two or more of R ³ , R ⁴ and R ⁵ may be combined with each other to form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded. The total number of carbon atoms of R ³ , R ⁴ and R ⁵ is 3-20.

The monovalent hydrocarbon groups include monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group having 3 to 18 carbon atoms having 1 to 18 carbon atoms represented by R ³ and R ⁴ And monovalent aromatic hydrocarbon groups having 6 to 18 carbon atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 18 carbon atoms include alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group;
An alkenyl group such as an ethenyl group, a propenyl group, a butenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group and butynyl group.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 18 carbon atoms include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group;
A polycyclic alicyclic saturated hydrocarbon group such as a norbornyl group or an adamantyl group;
A cycloalkenyl group such as a cyclopentenyl group and a cyclohexenyl group;
Examples thereof include polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group, and anthryl group;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, and naphthylmethyl group.

Of these monovalent hydrocarbon groups, an alkyl group is preferable.

Examples of the substituent for the monovalent hydrocarbon group represented by R ³ and R ⁴ include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, fluorinated alkyl group, hydroxy group, carboxy group, cyano group, Examples thereof include a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, and an acyloxy group.

Of these substituents, a hydroxy group, an alkoxy group, a fluorine atom, a trifluoromethyl group, and a cyano group are preferable.

Examples of the divalent hydrocarbon group having 1 to 18 carbon atoms represented by R ⁵ include those having 1 to 18 carbon atoms among the divalent hydrocarbon groups exemplified as the divalent organic group for R ¹ above. Etc.

Of these, monovalent chain hydrocarbon groups are preferred, alkanediyl groups are more preferred, alkanediyl groups having 1 to 4 carbon atoms are more preferred, and methanediyl groups are particularly preferred.

R ⁵ is preferably a single bond or a methanediyl group. Examples of the ring structure having 3 to 20 ring members formed by combining two or more of R ³ , R ⁴ and R ⁵ together with the carbon atom to which they are bonded include, for example, a cyclopropane structure, a cyclobutane structure, a cyclopentane Examples thereof include alicyclic structures such as a structure, cyclohexane structure, norbornane structure and adamantane structure; and aliphatic heterocyclic structures such as an oxacyclopentane structure, an oxacyclohexane structure, an azacyclopentane structure and a thiacyclopentane structure.

Examples of the group (X) include groups represented by the following formulas (X-1) to (X-15).

In the above formulas (X-1) to (X-15), * and ** are synonymous with the above formula (X).

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ² include, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon boundary of this hydrocarbon group, or a terminal on the bond side. And a group (a) containing a monovalent heteroatom-containing group, a group obtained by substituting a part or all of the hydrogen atoms of the hydrocarbon group and group (a) with a monovalent heteroatom-containing group, and the like.

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

Examples of the halogen atom represented by R ² include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

R ² is preferably a halogen atom or a hydrocarbon group, more preferably a hydrocarbon group. n is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.

m is preferably 1 to 3, more preferably 1 and 2, and still more preferably 1. In the case where Ar is a benzene ring, —OH is preferably bonded to the para-position or meta-position of R ¹ , and more preferably bonded to the para-position. However, when R ⁵ is a single bond, it is preferable that —OH is bonded to the meta position because synthesis of the monomer giving the structural unit (I) becomes easier.

Examples of the group (I) include groups represented by the following formulas (a1) to (a12) (hereinafter also referred to as “groups (I-1) to (I-12)”).

In the above formulas (a1) to (a12), * is synonymous with the above formula (1).

Of these, the groups (I-1) to (I-3) are preferred.

Examples of the structural unit (I) include structural units represented by the following formulas (1-1) to (1-3) (hereinafter also referred to as structural units (I-1) to (I-3)). It is done.

In the above formulas (1-1) to (1-3), Z is a group represented by the above formula (1).
In the above formula (1-1), R ⁶ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In the above formula (1-2), R ⁷ is a hydrogen atom or a methyl group. R ⁸ is a single bond, —O—, —COO— or —CONH—. R ⁹ is a monovalent organic group having 1 to 10 carbon atoms.
a is an integer of 0 to 4. when a is 2 or more, a plurality of R ⁹ may be the same or different.
In the above formula (1-3), R ¹⁰ is a hydrogen atom or a methyl group. R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. Two or more of one or more of R ¹¹ and R ¹² and R ¹³ may be combined with each other to form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded. b is an integer of 1 to 4. When b is 2 or more, the plurality of R ¹¹ may be the same or different, and the plurality of R ¹² may be the same or different. R ¹⁴ is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹³ and R ¹⁴ may be combined with each other to form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded.

R ⁶ is preferably a hydrogen atom and a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (I).
R ⁷ is preferably a hydrogen atom and a methyl group, more preferably a hydrogen atom, from the viewpoint of copolymerization of the monomer that gives the structural unit (I).
R ¹⁰ is preferably a hydrogen atom and a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (I).

R ⁸ is preferably a single bond, —COO— or —CONH—, and more preferably a single bond.
R ⁹ is preferably an alkyl group having 1 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group, a methoxy group or an ethoxy group.
a is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.

R ¹¹ , R ¹² and R ¹³ are preferably a hydrogen atom, a halogen atom and a chain hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom, a fluorine atom and an alkyl group, a hydrogen atom, a fluorine atom and A methyl group is more preferable, and a hydrogen atom is particularly preferable.
b is preferably 1 to 3, more preferably 1 and 2, and still more preferably 1.

R ¹⁴ is preferably a single bond and a divalent hydrocarbon group having 1 to 20 carbon atoms, more preferably a single bond and an alkanediyl group having 1 to 10 carbon atoms, and further a single bond, a methanediyl group and an ethanediyl group. Preferably, a single bond is particularly preferable.

The two or more, or ^{R 13} and ^{R 14} are ring structure composed ring members 3-20 are combined with each other of said one or more ^{R 11} and ^{R 12} and ^{R 13,} for example, cyclopropane Structures, cyclobutane structures, cyclopentane structures, cycloalkane structures such as cyclohexane structures;
Polycyclic alicyclic saturated hydrocarbon structures such as norbornane structure and adamantane structure;
Examples thereof include aliphatic heterocyclic structures such as an oxacyclopentane structure, an oxacyclohexane structure, an azacyclopentane structure, and a thiacyclopentane structure.

Examples of the structural unit (I-1) include structural units represented by the following formulas (1-1-1) and (1-1-2), and the structural unit (I-2) includes the following formula ( The structural units represented by 1-2-1) to (1-2-3) are structural units (I-3) represented by the following formulas (1-3-1) to (1-3-3): The structural unit represented by each is mentioned.

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

Of these, the structural unit (I-1) is preferable as the structural unit (I), and the structural unit represented by the formula (1-1-1) is more preferable.

As a minimum of the content rate of structural unit (I), 1 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 5 mol% is more preferable, 8 mol% is further more preferable, 14 mol % Is particularly preferred. As an upper limit of the content rate of structural unit (I), 70 mol% is preferable, 50 mol% is more preferable, 35 mol% is further more preferable, 25 mol% is especially preferable. By making the content rate of structural unit (I) into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved. When the said content rate is less than the said minimum, the pattern formation property of the said radiation sensitive resin composition may fall. When the said content rate exceeds the said upper limit, the adhesiveness to the board | substrate of the resist film formed from the said radiation sensitive resin composition may fall.

Examples of the monomer giving the structural unit (I) include compounds represented by the following formula (i).

In the above formula (i), Ar is a (m + n + 1) -valent group derived from an aromatic ring having 6 to 30 carbon atoms. R ¹ is a divalent organic group having 3 to 20 carbon atoms. R ² is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. m is an integer of 1 to 13. n is an integer of 0 to 13. However, m + n is 13 or less. When n is 2 or more, the plurality of R ² may be the same or different. A is —COO—, —SO ₂ O— or —R ^a —O—. R ^a is a substituted or unsubstituted arenediyl group. R ¹⁹ is a monovalent group containing a polymerizable carbon-carbon double bond.

The arenediyl group represented by R ^a, for example, benzene-diyl group, a naphthalene-diyl group, an anthracene-diyl group and the like. Of these, a benzenediyl group is preferred.
Examples of the substituent for the arenediyl group include a halogen atom, a hydroxy group, a cyano group, a nitro group, and an alkoxy group.

Examples of the monovalent group containing a polymerizable carbon-carbon double bond represented by R ¹⁹ include a vinyl group, a propenyl group, and a butenyl group.

Examples of the compound (i) include compounds represented by the following formulas (i-1) to (i-14) (hereinafter also referred to as “compounds (i-1) to (i-14)”). It is done.

In the above formulas (i-1) to (i-14), R ¹⁰ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹¹ is a hydrogen atom or a methyl group. R ¹⁴ is a hydrogen atom or a methyl group.

The compound (i) can be synthesized according to the following scheme, for example, in the case of the compound (i ′) in which A in the formula (i) is —COO—.

In the above scheme, Ar is a (m + n + 1) -valent group derived from an aromatic ring having 6 to 30 carbon atoms. R ¹ is a divalent organic group having 3 to 20 carbon atoms. R ² is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. m is an integer of 1 to 13. n is an integer of 0 to 13. However, m + n is 13 or less. When n is 2 or more, the plurality of R ² may be the same or different. J is a halogen atom, a hydroxy group or —OCOR ′. R ′ is a monovalent hydrocarbon group. R ¹⁹ is a polymerizable carbon - is a monovalent group containing a carbon double bond.

Examples of the halogen atom represented by J include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a chlorine atom and a bromine atom are preferable, and a chlorine atom is more preferable.

A polymerizable carbon-carbon double bond-containing compound represented by the above formula (ia) and a hydroxy compound represented by the above formula (ib) are combined with triethylamine, 1,4-diazabicyclo [2.2. .2] Compound (i ′) can be obtained by reacting in a solvent such as acetonitrile in the presence of a base such as octane. The compound (i ′) can be isolated by appropriately purifying the obtained product by column chromatography, recrystallization, distillation or the like.

Compound (i) other than the above compound (i ′) can also be synthesized by the same method as described above.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a group (z) having a hydroxy group at the terminal and a carbon atom adjacent to the hydroxy group having at least one fluorine atom or fluorinated alkyl group. [A] By having the structural unit (II), the polymer can adjust the solubility in the developer more appropriately, and as a result, the LWR performance and the like of the radiation-sensitive resin composition are further improved. Can be made. Moreover, the sensitivity of the said radiation sensitive resin composition in the case of EUV exposure and electron beam exposure can be improved.

Examples of the group (z) include groups represented by the following formula (Y).

In the above formula (Y), R ¹⁵ and R ¹⁶ are each independently an alkyl group having 1 to 10 carbon atoms or a fluorinated alkyl group having 1 to 10 carbon atoms. However, at least one of R ¹⁵ and R ¹⁶ is a fluorinated alkyl group. * Indicates a binding site to a moiety other than the group represented by the formula (Y) in the structural unit (II).

Examples of the fluorinated alkyl group having 1 to 10 carbon atoms represented by R ¹⁵ and R ¹⁶ include, for example, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, Examples include a pentafluoroethyl group, a hexafluoropropyl group, a heptafluoropropyl group, and a nonafluorobutyl group.
Among these, a trifluoromethyl group and a pentafluoroethyl group are preferable, and a trifluoromethyl group is more preferable.

The group (z) is preferably a hydroxy-di (trifluoromethyl) methyl group, a hydroxy-di (pentafluoroethyl) methyl group, or a hydroxy-methyl-trifluoromethylmethyl group, and hydroxy-di (trifluoromethyl). A methyl group is more preferred.

Examples of the structural unit (II) include structural units represented by the following formulas (2-1) to (2-6) (hereinafter also referred to as “structural units (II-1) to (II-6)”), etc. Is mentioned.

In the above formulas (2-1) to (2-6), R ^L3 is independently a hydrogen atom or a methyl group.

Of these, the structural unit (II-1) and the structural unit (II-2) are preferable.

[A] When the polymer has the structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 5 mol% with respect to all the structural units constituting the [A] polymer. Mole% is more preferable. As an upper limit of the content rate of structural unit (II), 60 mol% is preferable, 50 mol% is more preferable, and 45 mol% is further more preferable. By making the content rate of structural unit (II) into the said range, the said radiation sensitive resin composition can further improve LWR performance etc. Moreover, the sensitivity in KrF exposure, EUV exposure, and electron beam exposure can be improved more.

[Structural unit (III)]
The structural unit (III) is a structural unit represented by the following formula (3-1) or (3-2) (hereinafter also referred to as “structural unit (III-1) or (III-2)”). The group represented by —CR ²¹ R ²² R ²³ in the following formula (3-1) and the group represented by —CR ²⁵ R ²⁶ R ²⁷ in the following formula (3-2) are acid dissociable groups. [A] The polymer has the structural unit (III) in addition to the structural unit (I) as the structural unit containing an acid dissociable group, so that the solubility in the developer can be adjusted more appropriately. As a result, the LWR performance and the like of the radiation sensitive resin composition can be further improved.

In the above formula (3-1), R ²⁰ represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ²¹ is a monovalent alicyclic hydrocarbon group having a monovalent chain hydrocarbon group or a C 3-20 having 1 to 10 carbon atoms. R ²² and R ²³ are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups Represents an alicyclic structure having 3 to 20 carbon atoms which is constituted together with carbon atoms to which they are bonded to each other.
In the above formula (3-2), R ²⁴ represents a hydrogen atom or a methyl group. L ¹ is a single bond, —CCOO— or —CONH—. R ²⁵ , R ²⁶ and R ²⁷ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms.

As the structural unit (III-1), structural units represented by the following formulas (3-1-1) to (3-1-4) (hereinafter referred to as “structural units (III-1-1) to (III-1) -4) ") is preferred. As the structural unit (III-2), a structural unit represented by the following formula (3-2-1) (hereinafter also referred to as “structural unit (III-2-1)”) is preferable.

In the above formulas (3-1-1) to (3-1-4), R ²⁰ to R ²³ have the same meanings as the above formula (3-1). n _p is each independently an integer of 1 to 4.
In the above formula (3-2-1), R ²⁴ to R ²⁷ have the same meaning as in the above formula (3-2).

Examples of the structural unit (III-1) include a structural unit represented by the following formula.

In the above formula, R ²⁰ has the same meaning as in the above formula (3-1).

Examples of the structural unit (III-2) include a structural unit represented by the following formula.

In the above formula, R ²⁴ has the same meaning as in the above formula (3-2).

The structural unit (III-1) includes a structural unit derived from 2-alkyladamantan-2-yl (meth) acrylate, a structural unit derived from 1-alkylcyclopentan-1-yl (meth) acrylate, 2- Structural units derived from adamantyl-2-propyl (meth) acrylate, structural units derived from 2-cyclohexyl-2-propyl (meth) acrylate, and structures derived from 2-alkyltetracyclododecan-2-yl (meth) acrylate Units are preferred.
The structural unit (III-2) is preferably a structural unit derived from 1-oxyhydrocarbon-substituted-1-alkyloxystyrene, more preferably a structural unit derived from 1-cycloalkyl-1-alkyloxystyrene, More preferred are structural units derived from 1-cyclohexylethyloxy-1-ethyloxystyrene.

[A] When the polymer has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 5 mol% with respect to all the structural units constituting the [A] polymer. Mole% is more preferable, and 15 mol% is more preferable. As an upper limit of the content rate of structural unit (III), 80 mol% is preferable, 60 mol% is more preferable, and 45 mol% is further more preferable. By making the said content rate into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved more.

[A] As the lower limit of the content ratio of the structural unit containing an acid dissociable group in the polymer, that is, the total content ratio of the structural unit (I) and the structural unit (III), [A] the total structure constituting the polymer 20 mol% is preferable with respect to a unit, 50 mol% is more preferable, and 60 mol% is further more preferable. The upper limit of the total content of the structural unit (I) and the structural unit (III) is preferably 80 mol%, more preferably 70 mol%, and even more preferably 65 mol%. By making the said total content rate into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved further.

[Structural unit (IV)]
The structural unit (IV) is a structural unit (excluding the structural unit (I)) including a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. [A] Since the polymer further has the structural unit (IV), the solubility in the developer can be further adjusted, and as a result, the LWR performance and the like of the radiation-sensitive resin composition are further improved. be able to. Moreover, the adhesiveness of the resist pattern formed from the said radiation sensitive resin composition and a board | substrate can be improved.

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

In the above formula, R ^L1 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

Among these, the structural unit (IV) is preferably a structural unit containing a lactone structure, more preferably a structural unit containing a norbornane lactone structure, a structural unit containing an oxynorbornane lactone structure, or a structural unit containing a γ-butyrolactone structure. , A structural unit derived from norbornanelactone-yl (meth) acrylate, a structural unit derived from cyanonorbornanelactone-yl (meth) acrylate, a structural unit derived from oxynorbornanelactone-yl (meth) acrylate, and a butyrolactone-yl (meth) More preferred are structural units derived from acrylates.

[A] When a polymer has a structural unit (IV), as a minimum of the content rate of a structural unit (IV), 1 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 5 Mole% is more preferable, and 10 mol% is more preferable. As an upper limit of the content rate of structural unit (IV), 70 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 65 mol% is more preferable, and 60 mol% is further more preferable. By making the said content rate into the said range, the LWR performance etc. of the said radiation sensitive resin composition can be improved further. Moreover, the adhesiveness to the board | substrate of the resist pattern formed from the said radiation sensitive resin composition can be improved more.

[Structural unit (V)]
The structural unit (V) is a structural unit having an alcoholic hydroxyl group (excluding the structural unit (I)). [A] The polymer further has the structural unit (V), so that the solubility in the developer can be further adjusted, and as a result, the LWR performance and the like of the radiation-sensitive resin composition are further improved. be able to.

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

In the above formula, R ^L2 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

Of these, structural units derived from 3-hydroxyadamantan-1-yl (meth) acrylate are preferred.

[A] When a polymer has a structural unit (V), as a minimum of the content rate of a structural unit (V), 1 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 3 Mole% is more preferable. As an upper limit of the content rate of a structural unit (V), 50 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 40 mol% is more preferable, and 30 mol% is further more preferable. By making the said content rate into the said range, the LWR performance etc. of the said radiation sensitive resin composition can be improved further.

[Structural unit (VI)]
The structural unit (VI) is a structural unit containing a phenolic hydroxyl group (excluding the structural unit (I)). [A] By further having the structural unit (VI), the polymer can adjust the solubility in the developer more appropriately, and as a result, the LWR performance of the radiation-sensitive resin composition is further improved. be able to. In addition, the adhesion of the resulting resist pattern to the substrate can be improved. Furthermore, in the case of KrF exposure, EUV exposure, or electron beam exposure, the sensitivity of the radiation sensitive resin composition can be increased.

Examples of the structural unit (VI) include a structural unit represented by the following formula (6) (hereinafter also referred to as “structural unit (VI-1)”).

In said formula (6), R <^28> is a hydrogen atom or a methyl group. L ² is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ²⁹ is a monovalent organic group having 1 to 20 carbon atoms. q is an integer of 0 to 9. When q is 2 or more, the plurality of R ²⁹ may be the same or different. r is an integer of 1 to 3. p is an integer of 0-2.

Examples of the structural unit (VI-1) include structural units represented by the following formulas (6-1) to (6-7) (hereinafter referred to as “structural units (VI-1-1) to (VI-1-7)”. ) ")) And the like.

In the above formulas (6-1) to (6-7), R ^C each independently represents a hydrogen atom or a methyl group.

Of these, the structural unit (VI-1-1) is preferred.

[A] When the polymer has a structural unit (VI), the lower limit of the content ratio of the structural unit (VI) is preferably 3 mol% with respect to all the structural units constituting the [A] polymer. Mole% is more preferable. As an upper limit of the content rate of structural unit (II), 80 mol% is preferable, 70 mol% is more preferable, and 65 mol% is further more preferable. By making the content rate of structural unit (VI) into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved further. Moreover, the sensitivity in the case of KrF exposure, EUV exposure, or electron beam exposure can be improved more.

The structural unit (VI) is obtained by polymerizing a monomer obtained by converting the hydrogen atom of the —OH group of hydroxystyrene with an acetyl group and the like, and then subjecting the obtained polymer to a hydrolysis reaction in the presence of a base such as an amine. It can be formed by performing etc.

[Other structural units]
[A] The polymer may have other structural units in addition to the structural units (I) to (VI). Examples of the other structural unit include a structural unit containing a fluorine atom and a structural unit containing an alicyclic hydrocarbon group. As an upper limit of the content rate of the said other structural unit, 30 mol% is preferable with respect to all the structural units which comprise a [A] polymer, and 20 mol% is more preferable.

[A] The content of the polymer is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 85% by mass or more based on the total solid content of the radiation-sensitive resin composition.

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized, for example, by polymerizing monomers that give each structural unit in a suitable solvent using a radical polymerization initiator or the like.

Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpropylene). Pionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), azo radical initiators such as dimethyl 2,2′-azobisisobutyrate; benzoyl peroxide, t-butyl hydroperoxide, And peroxide radical initiators such as cumene hydroperoxide. Of these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferable, and AIBN is more preferable. These radical initiators can be used alone or in combination of two or more.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane;
Polycyclic alicyclic saturated hydrocarbons such as decalin and norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. The solvent used for these polymerizations may be used alone or in combination of two or more.

The lower limit of the reaction temperature in the polymerization is preferably 40 ° C, more preferably 50 ° C. As an upper limit of the said reaction temperature, 150 degreeC is preferable and 120 degreeC is more preferable. As a minimum of reaction time in the above-mentioned polymerization, 1 hour is preferred and 2 hours is more preferred. The upper limit of the reaction time is preferably 48 hours, more preferably 24 hours.

[A] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is not particularly limited, but the lower limit of the Mw is preferably 1,000, more preferably 2,000, Is more preferable, and 5,000 is particularly preferable. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000. [A] By making Mw of a polymer into the said range, the applicability | paintability and development defect inhibitory property of the said radiation sensitive resin composition improve. [A] If the Mw of the polymer is less than the lower limit, a resist film having sufficient heat resistance may not be obtained. [A] If the Mw of the polymer exceeds the above upper limit, the developability of the resist film may deteriorate.

[A] The ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is usually from 1 to 5, preferably from 1 to 3, more preferably from 1 to 2. .

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

<[B] Acid generator>
[B] The acid generator is a compound represented by the following formula (b). [B] The acid generator is a substance that generates an acid upon exposure. The generated acid dissociates the acid dissociable group of the [A] polymer and the like to generate a carboxy group, a hydroxy group, and the like, and the solubility of the [A] polymer in the developer changes. A resist pattern can be formed from the radiation resin composition.

In the above formula (b), R ^p1 is a monovalent group containing a ring structure having 6 or more ring members. R ^p2 is a divalent linking group. R ^p3 and R ^p4 are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ^p5 and R ^p6 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. n ^p1 is an integer of 0 to 10. n ^p2 is an integer of 0 to 10. n ^p3 is an integer of 1 to 10. When n ^p1 is 2 or more, the plurality of R ^p2 may be the same or different. When n ^p2 is 2 or more, the plurality of R ^p3 may be the same or different, and the plurality of R ^p4 may be the same or different. When n ^p3 is 2 or more, the plurality of R ^p5 may be the same or different, and the plurality of R ^p6 may be the same or different. X ⁺ is a monovalent radiation-sensitive onium cation.

Examples of the monovalent group including a ring structure having 6 or more ring members represented by R ^p1 include a monovalent group including an alicyclic structure having 6 or more ring members and an aliphatic heterocyclic structure having 6 or more ring members. A monovalent group, a monovalent group containing an aromatic ring structure having 6 or more ring members, a monovalent group containing an aromatic heterocyclic structure having 6 or more ring members, and the like.

Examples of the alicyclic structure having 6 or more ring members include monocyclic cycloalkane structures such as a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure;
Monocyclic cycloalkene structures such as cyclohexene structure, cycloheptene structure, cyclooctene structure, cyclodecene structure;
Polycyclic alicyclic saturated hydrocarbon structures such as norbornane structure, adamantane structure, tricyclodecane structure, tetracyclododecane structure;
Examples thereof include polycyclic alicyclic unsaturated hydrocarbon structures such as a norbornene structure and a tricyclodecene structure.

Examples of the aliphatic heterocyclic structure having 6 or more ring members include lactone structures such as a hexanolactone structure and a norbornane lactone structure;
Sultone structures such as hexanosultone structure and norbornane sultone structure;
An oxygen atom-containing heterocyclic structure such as an oxacycloheptane structure or an oxanorbornane structure;
Nitrogen atom-containing heterocyclic structures such as azacyclohexane structure and diazabicyclooctane structure;
Examples thereof include a sulfur atom-containing heterocyclic structure such as a thiacyclohexane structure and a thianorbornane structure.

Examples of the aromatic ring structure having 6 or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, and an anthracene structure.

Examples of the aromatic heterocyclic structure having 6 or more ring members include oxygen atom-containing heterocyclic structures such as furan structure, pyran structure and benzopyran structure, nitrogen atom-containing heterocyclic structures such as pyridine structure, pyrimidine structure and indole structure. Can be mentioned.

The lower limit of the number of ring members of the ring structure of R ^p1 is preferably 7, more preferably 8, more preferably 9, and particularly preferably 10. On the other hand, the upper limit of the number of ring members is preferably 15, more preferably 14, still more preferably 13, and particularly preferably 12. By setting the number of ring members in the above range, the acid diffusion length can be further appropriately shortened, and as a result, the LWR performance and the like of the radiation-sensitive resin composition can be further improved.

A part or all of the hydrogen atoms ^{contained in} 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, acyl group, Examples include an acyloxy group. Of these, a hydroxy group is preferred.

Among these, R ^p1 is preferably a monovalent group containing an alicyclic structure having 6 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members, and an alicyclic group having 9 or more ring members. More preferred are a monovalent group containing a ring structure and a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members, such as an adamantyl group, a hydroxyadamantyl group, a norbornanelactone-yl group, a norbornane sultone-yl group, and 5- An oxo-4-oxatricyclo [4.3.1.1 ^3,8 ] undecan-yl group is more preferred, and an adamantyl group is particularly preferred.

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. The divalent linking group represented by R ^p2 is preferably a carbonyloxy group, a sulfonyl group, an alkanediyl group and a cycloalkanediyl group, more preferably a carbonyloxy group and a cycloalkanediyl group, a carbonyloxy group and a norbornanediyl group. A group is more preferred, and a carbonyloxy group is particularly preferred.

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. R ^p3 and R ^p4 are preferably a hydrogen atom, a fluorine atom and a fluorinated alkyl group, more preferably a fluorine atom and a perfluoroalkyl group, and still more preferably a fluorine atom and a trifluoromethyl group.

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. R ^p5 and R ^p6 are preferably a fluorine atom and a fluorinated alkyl group, more preferably a fluorine atom and a perfluoroalkyl group, still more preferably a fluorine atom and a trifluoromethyl group, and particularly preferably a fluorine atom.

n ^p1 is preferably an integer of 0 to 5, more preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and particularly preferably 0 and 1.

n ^p2 is preferably an integer of 0 to 5, more preferably an integer of 0 to 2, still more preferably 0 and 1, and particularly preferably 0.

n ^p3 is preferably an integer of 1 to 5, more preferably an integer of 1 to 4, still more preferably an integer of 1 to 3, and particularly preferably 1 and 2.

The monovalent radiation-sensitive onium cation represented by X ⁺ is a cation that decomposes upon exposure to exposure light. In the exposed portion, sulfonic acid is generated from protons generated by the decomposition of the photodegradable onium cation and a sulfonate anion. Examples of the monovalent radiation-sensitive onium cation represented by the above X ⁺ include a cation represented by the following formula (ba) (hereinafter also referred to as “cation (ba)”), and the following formula (b -B) cation (hereinafter also referred to as “cation (bb)”), cation represented by the following formula (bc) (hereinafter also referred to as “cation (bc)”), etc. Is mentioned.

In the above formula (ba), R ^B3 , R ^B4 and R ^B5 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted group. An aromatic hydrocarbon group having 6 to 12 carbon atoms, —OSO ₂ —R ^BB1 or —SO ₂ —R ^BB2 , or a ring structure in which two or more of these groups are combined with each other .
R ^BB1 and R ^BB2 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. b1, b2 and b3 are each independently an integer of 0 to 5. R ^B3 ~ ^{R B5} and ^{R BB1} and when ^{R BB2} is plural, respectively, may be different in each of a plurality of ^R B3 ^{~ R B5} and ^{R BB1} and ^{R BB2} is the same.

In the above formula (bb), R ^B6 represents a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms. It is.
b4 is an integer of 0 to 7. If R ^B6 is plural, the plurality of R ^B6 may be the same or different, and plural R ^B6 may represent a constructed ring aligned with each other.
R ^B7 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. b5 is an integer of 0 to 6. If R ^B7 is plural, R ^B7 may be the same or different, and plural R ^B7 may represent a keyed configured ring structure. n _b2 is an integer of 0 to 3. R ^B8 is a single bond or a divalent organic group having 1 to 20 carbon atoms. n _b1 is an integer of 0-2.

In the above formula ( ^bc ), R ^B9 and R ^B10 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 6 Or an aromatic hydrocarbon group of ^˜12 , —OSO ₂ —R ^BB3 or —SO ₂ —R ^BB4 , or a ring structure in which two or more of these groups are combined with each other. R ^BB3 and R ^BB4 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. b6 and b7 are each independently an integer of 0 to 5. ^{^R ^B9,} R B10, R ^BB3 and when ^{R BB4} is plural respective plurality of ^{^R ^B9,} ^R ^B10, ^R ^BB3 and ^{R BB4} may have respectively the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include, for example, a methyl group, an ethyl group, an n-propyl group, an n- A butyl group etc. are mentioned.

Examples of the unsubstituted branched alkyl group represented by R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include an i-propyl group, an i-butyl group, and a sec-butyl group. , T-butyl group and the like.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^B3 , R ^B4 , R ^B5 , R ^B9, and R ^B10 include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group;
Examples include aralkyl groups such as benzyl group and phenethyl group.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^B6 and R ^B7 include a phenyl group, a tolyl group, and a benzyl group.

Examples of the divalent organic group represented by R ^B8 include a single bond or a divalent organic group having 1 to 20 carbon atoms.

Examples of the substituent that may be substituted for the hydrogen atom of the alkyl group and the aromatic hydrocarbon group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a hydroxy group, a carboxy group, a cyano group, Examples thereof include a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, and an acyloxy group. Among these, a halogen atom is preferable and a fluorine atom is more preferable.

R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic carbonization A hydrogen group, —OSO ₂ —R ^BB5 and —SO ₂ —R ^BB5 are preferred, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferred, and a fluorinated alkyl group is more preferred. R ^BB5 is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

In formula (ba), b1, b2 and b3 are preferably integers of 0 to 2, more preferably 0 and 1, and still more preferably 0. As b4 in the formula (bb), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 1 is more preferable. b5 is preferably an integer of 0 to 2, more preferably 0 and 1, and still more preferably 0. As _nb2 , 2 and 3 are preferable and 2 is more preferable. As _nb1 , 0 and 1 are preferable and 0 is more preferable. In formula (bc), b6 and b7 are preferably integers of 0 to 2, more preferably 0 and 1, and still more preferably 0.

X ⁺ is preferably a cation (ba) or a cation (bb), among which triphenylsulfonium cation and 1- [2- (4-cyclohexylphenylcarbonyl) propan-2-yl] tetrahydro A thiophenium cation is more preferred.

Examples of the acid generator represented by the above formula (b) include compounds represented by the following formulas (b-1) to (b-14) (hereinafter referred to as “compounds (b-1) to (b-14)”). Also).

In the above formulas (b-1) to (b-14), X ⁺ is a monovalent radiation-sensitive onium cation.

[B] As the acid generator, compounds (b-1), (b-4), (b-5), (b-11), (b-12) and (b-14) are more preferred.

[B] The lower limit of the content of the acid generator is preferably 0.1 parts by weight, more preferably 0.5 parts by weight, and even more preferably 1 part by weight with respect to 100 parts by weight of the [A] polymer. As an upper limit of the said content, 30 mass parts is preferable, 20 mass parts is more preferable, and 15 mass parts is further more preferable. [B] By making content of an acid generator into the said range, the sensitivity and developability of the said radiation sensitive resin composition improve, As a result, LWR performance and depth of focus can be improved. [B] 1 type (s) or 2 or more types can be used for an acid generator.

<[C] Acid diffusion controller>
The said radiation sensitive resin composition may contain a [C] acid diffusion control body as needed. [C] The acid diffusion control body controls the diffusion phenomenon in the resist film of the acid generated from the [B] acid generator by exposure, has the effect of suppressing undesirable chemical reactions in the non-exposed areas, and the radiation sensitivity obtained The storage stability of the photosensitive resin composition is further improved, the resolution of the resist is further improved, and the change in the line width of the resist pattern due to fluctuations in the holding time from exposure to development processing can be suppressed, thereby stabilizing the process. A radiation-sensitive resin composition having excellent properties can be obtained. [C] The content of the acid diffusion controller in the radiation-sensitive resin composition is incorporated as a part of the polymer even in the form of a free compound (hereinafter referred to as “[C] acid diffusion controller” as appropriate). Or both of these forms.

[C] Examples of the acid diffusion controller include a compound represented by the following formula (7a) (hereinafter also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (I)”). "Nitrogen-containing compound (II)"), compounds having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compound (III)"), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, etc. It is done.

In the above formula (7a), R ³² , R ³³ and R ³⁴ are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, aryl group or aralkyl group. .

Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine and tri-n-pentylamine; and aromatics such as aniline Group amines and the like.

Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, and the like.

Examples of the nitrogen-containing compound (III) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethylacrylamide.

Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. It is done.

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like.

Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N- (undecan-1-ylcarbonyloxyethyl) morpholine; pyrazine, pyrazole and the like. .

Moreover, the compound which has an acid dissociable group can also be used as said nitrogen-containing organic compound.
Examples of the nitrogen-containing organic compound having such an acid dissociable group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2 -Phenylbenzimidazole, N- (t-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine and the like.

Further, as the [C] acid diffusion control agent, a photodegradable base that is exposed to light and generates an acid upon exposure can also be used. Examples of the photodegradable base include an onium salt compound that loses acid diffusion controllability by being decomposed by exposure. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (7b-1), an iodonium salt compound represented by the following formula (7b-2), and the like.

In the above formulas (7b-1) and (7b-2), R ³⁵ to R ³⁹ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group, or a halogen atom. E ⁻ and Q ⁻ are each independently OH ⁻ , R ^β —COO ⁻ , R ^γ —SO ₃ ^— or an anion represented by the following formula (7b-3). ^Rβ is an alkyl group or an aralkyl group. The R ^gamma, an alkyl group or an aralkyl group.

In the above formula (7b-3), R ⁴⁰ represents a linear or branched alkyl group having 1 to 12 carbon atoms in which part or all of the hydrogen atoms may be substituted with fluorine atoms, or 1 carbon atom 12 to 12 linear or branched alkoxyl groups. u is an integer of 0-2.

Examples of the photodegradable base include compounds represented by the following formulas.

Of these, the photodegradable base is preferably a sulfonium salt, more preferably a triarylsulfonium salt, and even more preferably triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate.

When the [C] acid diffusion controller is a [C] acid diffusion controller, the lower limit of the content of the [C] acid diffusion controller in the [A] polymer is 100 parts by mass of the [A] polymer. 0 parts by mass is preferable, 0.1 parts by mass is more preferable, 0.5 parts by mass is further preferable, and 1 part by mass is particularly preferable. [C] The upper limit of the content of the acid diffusion controller is preferably 20 parts by mass, more preferably 15 parts by mass, further preferably 10 parts by mass, and particularly preferably 7 parts by mass. [C] By setting the content of the acid diffusion controller within the above range, the resolution, storage stability, and the like of the radiation-sensitive resin composition can be improved. [C] When the content of the acid diffusion controller exceeds the upper limit, the sensitivity of the radiation-sensitive resin composition may be lowered.

<[D] solvent>
The radiation-sensitive resin composition usually contains a [D] solvent. [D] The 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, and the optionally contained [C] acid diffusion controller.

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

Examples of the alcohol solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec -Monoalcohol solvents such as heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
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, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of ketone solvents 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, Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
Examples include 2,4-pentanedione, acetonylacetone, acetophenone, and the like.

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

Examples of ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, i-pentyl acetate, sec Acetate solvents such as pentyl, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Polyhydric alcohol partial ether acetate solvents such as acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
Carbonate solvents such as dimethyl carbonate and diethyl carbonate;
Diethyl acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl acetoacetate, ethyl acetoacetate, methyl lactate, ethyl lactate N-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of hydrocarbon solvents include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene, n-amylnaphthalene Group hydrocarbon solvents and the like.

Of these, ester solvents and ketone solvents are preferred, polyhydric alcohol partial ether acetate solvents and cyclic ketone solvents are more preferred, and propylene glycol monomethyl ether acetate and cyclohexanone are even more preferred. The radiation-sensitive resin composition may contain one or more [D] solvents.

<Other optional components>
In addition to the above components [A] to [D], the radiation sensitive resin composition includes, as other optional components, for example, acid generators other than [B] acid generators (hereinafter referred to as “other acid generators”). Or a fluorine atom-containing polymer, a surfactant, an alicyclic skeleton-containing compound, a sensitizer, and the like. The said radiation sensitive resin composition may contain 1 type (s) or 2 or more types of other arbitrary components, respectively.

(Other acid generators)
The said radiation sensitive resin composition may contain the other acid generator in the range which does not impair the effect of this invention. The content of the other acid generator may be a low molecular weight compound (hereinafter also referred to as “other acid generator” as appropriate) or an acid generator group incorporated as part of the polymer. Both forms may be used. Specific examples of these acid generators include compounds described in paragraphs [0080] to [0113] of JP-A-2009-134088.

Further, as another acid generator, a polymer having a structural unit represented by the following formula (7) is also preferable.

In said formula (7), R 'is a hydrogen atom or a methyl group. X ⁺ is a monovalent radiation-sensitive onium cation.

When the said radiation sensitive resin composition contains another acid generator, as an upper limit of content of another acid generator, 10 mass parts is preferable with respect to 100 mass parts of [A] polymers, 5 Part by mass is more preferable.

(Fluorine atom-containing polymer)
The radiation sensitive resin composition may further contain a fluorine atom-containing polymer (except for those corresponding to the [A] polymer). When the radiation-sensitive resin composition contains a fluorine atom-containing polymer, when the resist film is formed, the distribution is unevenly distributed near the resist film surface due to the oil-repellent characteristics of the fluorine atom-containing polymer in the resist film. It is possible to prevent the acid generator, the acid diffusion controller and the like from being eluted into the immersion medium during immersion exposure. Further, due to the water-repellent characteristics of this fluorine atom-containing polymer, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range, and the occurrence of bubble defects can be suppressed. Furthermore, the receding contact angle between the resist film and the immersion medium is increased, and high-speed scanning exposure is possible without leaving water droplets. Thus, the said radiation sensitive resin composition can form the resist film suitable for an immersion exposure method by further containing a fluorine atom containing polymer.

The fluorine atom-containing polymer is not particularly limited as long as it is a polymer having a fluorine atom, but the fluorine atom content (% by mass) is higher than the [A] polymer of the radiation-sensitive resin composition. Is preferred. Examples of the fluorine atom-containing polymer include 1,1,1,3,3,3-hexafluoro-2-propyl (meth) acrylate, 1,1-difluoro-1-ethoxycarbonylbutan-2-yl (meth) And those having a structural unit derived from (meth) acrylate containing fluorine atoms such as acrylate.

The lower limit of the content of the fluorine atom-containing polymer is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and still more preferably 1 part by mass with respect to 100 parts by mass of the [A] polymer. As an upper limit of content of the said fluorine atom containing polymer, 20 mass parts is preferable, 15 mass parts is more preferable, and 10 mass parts is further more preferable.

(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, polyethylene glycol diacrylate. Nonionic surfactants such as stearate; commercially available products include KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, Tochem Products), MegaFuck F171, F173 (above, DIC), Florard FC430, FC431 (above, Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, Asahi Glass Industrial Co., Ltd.) Can be mentioned.
As content of the said surfactant, it is 2 mass parts or less normally with respect to 100 mass parts of [A] polymers.

(Alicyclic skeleton-containing compound)
The alicyclic skeleton-containing compound has an effect of improving dry etching resistance, pattern shape, adhesion to the substrate, and the like.

Examples of the alicyclic skeleton-containing compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl;
Deoxycholic acid esters such as t-butyl deoxycholic acid, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid;
Lithocholic acid esters such as tert-butyl lithocholic acid, tert-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid;
3- [2-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane, and the like.
As content of the said alicyclic skeleton containing compound, it is 5 mass parts or less normally with respect to 100 mass parts of [A] polymers.

(Sensitizer)
A sensitizer exhibits the effect | action which increases the production amount of the acid from [B] acid generator etc., and there exists an effect which improves the "apparent sensitivity" of the said radiation sensitive resin composition.

Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like. These sensitizers may be used alone or in combination of two or more.
As content of the said sensitizer, it is 2 mass parts or less normally with respect to 100 mass parts of [A] polymers.

<Method for preparing radiation-sensitive resin composition>
The radiation sensitive resin composition includes, for example, [A] polymer, [B] acid generator agent, optional components such as [C] acid diffusion controller contained as necessary, and [D] solvent. It can prepare by mixing in the ratio. The radiation-sensitive resin composition is preferably filtered after mixing with, for example, a filter having a pore size of about 0.2 μm. As a minimum of solid concentration of the radiation sensitive resin composition, 0.1 mass% is preferred, 0.5 mass% is more preferred, and 1 mass% is still more preferred. The upper limit of the solid content concentration of the radiation-sensitive resin composition is preferably 50% by mass, more preferably 30% by mass, and still more preferably 20% by mass.

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

Since the radiation-sensitive resin composition contains an aromatic ring in the structural unit (I) of the [A] polymer contained therein, it is particularly suitable for exposure by KrF excimer laser light, electron beam, or extreme ultraviolet (EUV). Can be suitably used.

<Resist pattern formation method>
The resist pattern forming method includes a step of forming a resist film (hereinafter also referred to as “resist film forming step”), a step of exposing the resist film (hereinafter also referred to as “exposure step”), and the exposed resist. A step of developing the film (hereinafter also referred to as “developing step”). In the resist pattern forming method, the film is formed from the radiation-sensitive resin composition.

According to the resist pattern forming method, since the radiation sensitive resin composition described above is used, it is possible to form a pattern with high sensitivity and excellent nano edge roughness. Hereinafter, each step will be described.

[Resist film forming step]
In this step, a resist film is formed using the radiation sensitive resin composition. The resist film can be formed, for example, by applying a radiation sensitive resin composition on the substrate. Although it does not specifically limit as an application | coating method, For example, appropriate application | coating means, such as spin coating, cast coating, roll coating, can be employ | adopted. Examples of the substrate include a silicon wafer and a wafer coated with aluminum. Specifically, after the radiation-sensitive resin composition is applied so that the resulting film has a predetermined thickness, the solvent in the coating film is volatilized by pre-baking (PB) as necessary.

The lower limit of the average film thickness of the resist film is preferably 1 nm, more preferably 5 nm, still more preferably 10 nm, and particularly preferably 20 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 200 nm, further preferably 100 nm, and particularly preferably 50 nm.

The lower limit of the PB temperature is usually 60 ° C., preferably 80 ° C. As an upper limit of the temperature of PB, it is 140 degreeC normally and 120 degreeC is preferable. The lower limit of the PB time is usually 5 seconds, and preferably 10 seconds. The upper limit of the PB time is usually 600 seconds, and preferably 300 seconds.

[Exposure process]
In this step, the film formed in the film forming step is exposed. In some cases, this exposure is performed by irradiating radiation through a mask having a predetermined pattern through an immersion medium such as water. Examples of the radiation include visible rays, ultraviolet rays, far ultraviolet rays, vacuum ultraviolet rays (extreme ultraviolet rays (EUV); wavelength 13.5 nm), electromagnetic waves such as X-rays and γ rays, and charged particle beams such as electron rays and α rays. Can be mentioned. Among these, radiation that emits more secondary electrons from the [B] particles by exposure is preferable, and EUV, X-rays, and electron beams are more preferable.

Further, post-exposure baking (PEB) may be performed after exposure. As a minimum of the temperature of PEB, it is 50 degreeC normally and 80 degreeC is preferable. The upper limit of the PEB temperature is usually 180 ° C, preferably 130 ° C. The lower limit of the PEB time is usually 5 seconds, and preferably 10 seconds. The upper limit of the PEB time is usually 600 seconds, and preferably 300 seconds.

In the present invention, in order to maximize the potential of the radiation-sensitive resin composition, for example, an organic or inorganic antireflection film can be formed on the substrate to be used. Moreover, in order to prevent the influence of the basic impurity etc. which are contained in environmental atmosphere, a protective film can also be provided, for example on a coating film. When immersion exposure is performed, an immersion protective film may be provided on the film, for example, in order to avoid direct contact between the immersion medium and the film.

[Development process]
In this step, the film exposed in the exposure step is developed. Examples of the developer used for the development include an alkaline aqueous solution and an organic solvent-containing solution.

Examples of the alkaline aqueous solution include 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 an alkaline aqueous solution in which at least one alkaline compound is dissolved.

The lower limit of the content of the alkaline compound in the alkaline aqueous solution is preferably 0.1% by mass, more preferably 0.5% by mass, and even more preferably 1% by mass. As an upper limit of the said content, 20 mass% is preferable, 10 mass% is more preferable, and 5 mass% is further more preferable.

As the alkaline aqueous solution, a TMAH aqueous solution is preferable, and a 2.38 mass% TMAH aqueous solution is more preferable.

Examples of the organic solvent in the organic solvent-containing liquid include the same organic solvents exemplified as the [D] solvent of the radiation-sensitive resin composition. Of these, ester solvents are preferred, and butyl acetate is more preferred.

The lower limit of the content of the organic solvent in the organic solvent developer is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, and particularly preferably 99% by mass.

These developers may be used alone or in combination of two or more. In general, after development, the substrate is washed with water or the like and dried.

When a alkaline aqueous solution is used as the developer, a positive pattern can be obtained. In addition, when an organic solvent is used as the developer, a negative pattern can be obtained. From the viewpoint of further improving the film thickness suppression, an alkali developer is preferred.

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

[Weight average molecular weight (Mw), number average molecular weight (Mn) and dispersity (Mw / Mn)]
Mw and Mn of the polymer are GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL, Tosoh Corporation), flow rate 1.0 mL / min, elution solvent tetrahydrofuran, sample concentration 1.0 mass%, sample Measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard, using a differential refractometer as a detector under the analysis conditions of an injection amount of 100 μL and a column temperature of 40 ° C. The degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

[ ¹³ C-NMR analysis]
The ¹³ C-NMR analysis for determining the content (mol%) of the structural unit of the polymer uses a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.) and deuterated chloroform as a measurement solvent. went.

<[A] Synthesis of polymer>
(1) The monomer used for the synthesis of [A] polymer is shown below.

The compounds (M-1) to (M-4), (M-15) and (M-16) are structural units (I), and the compounds (M-12) and (M-13) are structural units. (II), compounds (M-5), (M-6) and (M-11) are structural units (III), and compounds (M-7) and (M-8) are structural units (IV). Compounds (M-9) and (M-10) give structural units (VI), respectively. In addition, the structural unit of the [B] acid generator is incorporated into the [A] polymer by the compound (M-14).

[Synthesis Example 1] (Synthesis of polymer (A-1))
29.24 g (20 mol%) of the above compound (M-1), 44.83 g (50 mol%) of the compound (M-6), 25.93 g (30 mol%) of the compound (M-10), and an initiator. 5.25 g of AIBN (6 mol% based on the total monomers) and 2.00 g of t-dodecyl mercaptan (2.28 mol% based on the total monomers) were dissolved in 200 g of propylene glycol monomethyl ether. Next, a 500 mL three-necked flask containing 100 g of propylene glycol monomethyl ether was purged with nitrogen for 30 minutes, and then heated to 85 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. . The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, 200 g of ethyl acetate, 120 g of methanol, 32 g of water and 800 g of hexane were added to the polymerization solution, mixed, and transferred to a 3 L separatory funnel. After standing for 30 minutes, the lower layer was recovered and solvent substitution was performed with propylene glycol monomethyl ether to obtain 200 g of a solution. Next, 250 g of methanol, 22 g of triethylamine and 4 g of water were added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the resulting polymer was dissolved in propylene glycol monomethyl ether acetate to obtain a solution containing the polymer (A-1) having a solid content concentration of 25% by mass (62 g). Yield 62%). Mw of the polymer (A-1) was 6,250, and Mw / Mn was 1.61. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from the structural unit derived from compound (M-1), compound (M-6) and p-hydroxystyrene was 19.0 mol%, 49 0.5 mol% and 31.5 mol%.

[Synthesis Examples 2 to 7, 12 to 15] (Synthesis of Polymers (A-2) to (A-6) and (A-11) to (A-15))
Polymers (A-2) to (A-6) and (A-11) to (A-) were prepared in the same manner as in Synthesis Example 1 except that the types and amounts of monomers shown in Table 1 were used. 15) was synthesized. In Table 1, it shows together about Mw of each obtained polymer, Mw / Mn, and each structural unit content rate. In Table 1, “-” indicates that the corresponding monomer was not used.

[Synthesis Example 8] (Synthesis of Polymer (A-7))
Compound (M-1) 28.51 g (20 mol%), Compound (M-6) 43.71 g (50 mol%), Compound (M-9) 27.78 g (30 mol%), initiator AIBN 5.12 g (6 mol% based on the total monomers) and t-dodecyl mercaptan 1.95 g (2.28 mol% based on the total monomers) were dissolved in 200 g of propylene glycol monomethyl ether. Next, a 500 mL three-necked flask containing 100 g of propylene glycol monomethyl ether was purged with nitrogen for 30 minutes, and then heated to 85 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. . The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, 200 g of ethyl acetate, 120 g of methanol, 32 g of water and 800 g of hexane were added to the polymerization solution, mixed, and transferred to a 3 L separatory funnel. After standing for 30 minutes, the lower layer was recovered and dissolved in propylene glycol monomethyl ether acetate to obtain a solution containing the polymer (A-7) having a solid content concentration of 25% by mass (67 g, yield 63%). . Mw of the polymer (A-7) was 6,670, and Mw / Mn was 1.66. As a result of ¹³ C-NMR analysis, the content of each structural unit derived from (M-1), (M-6) and (M-9) was 18.4 mol%, 49.7 mol% and 31 respectively. It was 9 mol%.

[Synthesis Examples 9 to 11] (Synthesis of Polymers (A-8) to (A-10))
Polymers (A-8) to (A-10) were synthesized in the same manner as in Synthesis Example 8 except that the types and amounts of monomers shown in Table 1 were used. In Table 1, it shows together about Mw of each obtained polymer, Mw / Mn, and each structural unit content rate.

<Preparation of radiation-sensitive resin composition>
It shows below about components other than the [A] polymer used for preparation of a radiation sensitive resin composition.

[[B] acid generator]
Each structural formula is shown below.
B-1: Triphenylsulfonium 3- (piperidin-1-ylsulfonyl) -1,1,2,2,3,3-hexafluoropropane-1-sulfonate B-2: Triphenylsulfonium adamantane-1-yloxy Carbonyl difluoromethanesulfonate B-3: Triphenylsulfonium 4- (adamantan-1-ylcarbonyloxy) -1,1,2,2-tetrafluorohexane-1-sulfonate B-4: Triphenylsulfonium norbornanelactone-2- Ileoxycarbonyldifluoromethanesulfonate B-5: Triphenylsulfonium norbornane sultone-2-yloxycarbonyldifluoromethanesulfonate B-6: Triphenylsulfonium nonafluoro n-butanesulfonate B-7: Trif Sulfonyl sulfonium 2,4-di (trifluoromethyl) benzenesulfonate

[[C] acid diffusion controller]
Each structural formula is shown below.
C-1: Triphenylsulfonium salicylate C-2: Triphenylsulfonium 10-camphorsulfonate C-3: N- (undecan-1-ylcarbonyloxyethyl) morpholine

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

[Example 1]
[A] 100 parts by mass of (A-1) as a polymer, [B] 27 parts by mass of (B-1) as an acid generator, [C] (C-1) 3.7 as an acid diffusion controller A radiation-sensitive resin composition (J-1) was prepared by mixing 4,583 parts by weight of (D-1) as a solvent and (D-2) 1,921 parts by weight of [D] solvent.

[Examples 2 to 18 and Comparative Examples 1 to 3]
Except that the components of the types and contents shown in Table 2 below were used, the same operations as in Example 1 were performed, and the radiation-sensitive resin compositions (J-2) to (J-18) and (CJ-2) ) To (CJ-4) were prepared. “-” In Table 2 indicates that the corresponding component was not used.

<Formation of resist pattern>
Using a spin coater (“CLEAN TRACK ACT8” manufactured by Tokyo Electron Ltd.) on the surface of an 8-inch silicon wafer, the prepared radiation sensitive resin composition was applied, PB was performed at 130 ° C. for 60 seconds, and at 23 ° C. After cooling for 30 seconds, a resist film having an average thickness of 50 nm was formed. Next, the resist film was irradiated with an electron beam by using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 90 ° C. for 60 seconds. Thereafter, development was performed at 23 ° C. for 30 seconds using a 2.38 mass% TMAH aqueous solution as an alkaline developer, washed with water, and dried to form a positive resist pattern.

<Evaluation>
About the formed resist pattern, the sensitivity of the said radiation sensitive resin composition, LWR performance, and film | membrane reduction inhibitory property were evaluated by performing the following measurement. A scanning electron microscope (Hitachi High-Technologies “S-9380”) was used to measure the resist pattern.
The evaluation results are shown in Table 3 below.

[sensitivity]
The resist pattern was observed from above the pattern using the scanning electron microscope. The exposure amount that becomes a line and space pattern with a line width of 150 nm was taken as the optimum exposure amount, and this optimum exposure amount was taken as the sensitivity (μC / cm ² ). The smaller the value, the better the sensitivity. The sensitivity is 10% or more compared with that of Comparative Example 1 (sensitivity value is 90% or less), “AA (very good)” and 0 to less than 10% improvement ( When the sensitivity value was 90% to 100%), “A (good)” was evaluated, and when the sensitivity value increased, “B (bad)” was evaluated.

[LWR performance]
The formed resist pattern was observed from above the pattern using the scanning electron microscope. A total of 50 line widths were measured at arbitrary points, and a 3-sigma value was obtained from the distribution of the measured values, and this was defined as LWR performance (nm). The LWR performance indicates that the smaller the value, the better. The LWR performance is “AA (very good)” in the case of an improvement of 10% or more (the value of LWR performance is 90% or less) compared with that of Comparative Example 1, and 0 to less than 10%. When the improvement (LWR performance value was 90% to 100%), the evaluation was “A (good)”, and when the LWR performance value increased, the evaluation was “B (defect)”.

[Membrane loss suppression]
Using a spin coater (CLEAN TRACK ACT8 manufactured by Tokyo Electron Co., Ltd.) on the surface of an 8-inch silicon wafer, each radiation sensitive resin composition shown in Table 2 was applied, and PB was performed at 130 ° C. for 60 seconds. Then, it developed for 30 seconds at 23 degreeC using 2.38 mass% TMAH aqueous solution as an alkali developing solution, washed with water, and dried. After completion of the series of processes, the average thickness of the remaining resist film was measured, and a value obtained by subtracting the remaining film thickness from the initial film thickness was defined as a film reduction (nm). For the film thickness measurement, an optical interference type film thickness measuring device (“Lambda Ace” manufactured by Dainippon Screen Mfg. Co., Ltd.) was used. The smaller the value is, the better this film reduction suppression property is.
When the film thickness is improved by 10% or more compared to that of Comparative Example 1 (the value of film thickness is 90% or less), “AA (very good)” is 0 to less than 10%. When the improvement (film reduction value is 90% to 100%), the evaluation was “A (good)”, and when the film reduction value increased, the evaluation was “B (poor)”.

From the results in Table 3, it was shown that the radiation-sensitive resin compositions of the examples were excellent in LWR performance and film reduction suppression while maintaining excellent sensitivity. On the other hand, it was also shown that the radiation sensitive resin composition of the comparative example was inferior to that of the example in terms of the above LWR performance and film loss suppression. In general, it is known that electron beam exposure shows the same tendency as EUV exposure. Therefore, even in the case of EUV exposure, it is presumed that the radiation sensitive resin compositions of the examples are excellent in LWR performance and the like.

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 that is excellent in LWR performance and film reduction inhibition while maintaining excellent sensitivity. Therefore, these can be suitably used for manufacturing semiconductor devices that are expected to be further miniaturized in the future.

Claims

A polymer having an acid dissociable group and a first structural unit containing an oxo acid group or a phenolic hydroxyl group protected by the acid dissociable group;
A radiation sensitive resin composition containing a radiation sensitive acid generator represented by the following formula (b):
The said acid dissociable group is represented by following formula (1), The radiation sensitive resin composition characterized by the above-mentioned.

(In the formula (1), Ar is a (m + n + 1) -valent group derived from an aromatic ring having 6 to 30 carbon atoms. R 1 is a divalent organic group having 3 to 20 carbon atoms. R 2 Is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, m is an integer of 1 to 13, n is an integer of 0 to 13, provided that m + n is 13 or less. When n is 2 or more, the plurality of R 2 may be the same or different. * Indicates the binding site to the oxy group in the protected oxo acid group or phenolic hydroxyl group.)

(In formula (b), R p1 is a monovalent group containing a ring structure having 6 or more ring members. R p2 is a divalent linking group. R p3 and R p4 are each independently , A hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, wherein R p5 and R p6 are each independently fluorine An atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, n p1 is an integer of 0 to 10. n p2 is an integer of 0 to 10. n p3 is 1 to 10 When n p1 is 2 or more, the plurality of R p2 may be the same or different, and when n p2 is 2 or more, the plurality of R p3 may be the same or different, and a plurality of R p2 p4 may be the same or different, and when n p3 is 2 or more, a plurality of R p5 may be the same or different. And a plurality of R p6 may be the same or different. X + is a monovalent radiation-sensitive onium cation.)
The radiation-sensitive resin composition according to claim 1, wherein the divalent organic group represented by R 1 in the formula (1) is represented by the following formula (X).

(In the formula (X), * represents a bonding site to the oxy group in the protected oxo acid group or phenolic hydroxyl group. ** represents a site bonded to the aromatic ring in Ar in the formula (1). R 3 and R 4 are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, and R 5 is a single bond, an oxygen atom or a divalent hydrocarbon group. Two or more of R 3 , R 4, and R 5 may be combined with each other to form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded, R 3 , R 4, and R 5 The total number of carbon atoms is 3 to 20.)
The radiation-sensitive resin composition according to claim 1, wherein the first structural unit is represented by the following formulas (1-1) to (1-3).

(In the formulas (1-1) to (1-3), Z is a group represented by the above formula (1).
In formula (1-1), R 6 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In formula (1-2), R 7 represents a hydrogen atom or a methyl group. R 8 is a single bond, —O—, —COO— or —CONH—. R 9 is a monovalent organic group having 1 to 10 carbon atoms. a is an integer of 0 to 4. when a is 2 or more, a plurality of R 9 may be the same or different.
In formula (1-3), R 10 represents a hydrogen atom or a methyl group. R 11 , R 12 and R 13 are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. Two or more of one or more of R 11 and R 12 and R 13 may be combined with each other to form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded. b is an integer of 1 to 4. When b is 2 or more, the plurality of R 11 may be the same or different, and the plurality of R 12 may be the same or different. R 14 is a single bond or a divalent organic group having 1 to 20 carbon atoms. R 13 and R 14 may be combined with each other to form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded. )
The radiation sensitive resin composition according to claim 1, wherein the polymer further has a second structural unit containing a group represented by the following formula (Y).

(In the formula (Y), R 15 and R 16 are each independently an alkyl group having 1 to 10 carbon atoms or a fluorinated alkyl group having 1 to 10 carbon atoms, provided that at least one of R 15 and R 16 One is a fluorinated alkyl group, and * represents a binding site to a portion other than the group represented by the above formula (Y) in the second structural unit.
The radiation sensitive resin composition according to any one of claims 1 to 4, further comprising a photodegradable base.
Forming a resist film;
A step of exposing the resist film, and a step of developing the exposed resist film,
A resist pattern forming method, wherein the resist film is formed from the radiation-sensitive resin composition according to any one of claims 1 to 5.
The resist pattern forming method according to claim 6, wherein the radiation used in the exposure step is extreme ultraviolet rays, electron beams, or X-rays.