JP2018097125A - Radiation-sensitive resin composition and method for forming resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition excellent in LWR performance or the like.SOLUTION: A radiation-sensitive resin composition comprises a first polymer having a first structural unit represented by formula (1) and a first radiation-sensitive acid generator generating sulfonic acid or disulfonylimidic acid. The first radiation-sensitive acid generator comprises an anion having a group including a polycyclic structure and having one or more fluorine atoms. In formula (1), Ris a monovalent hydrocarbon group having 1 to 20 carbon atoms; n is an integer of 0 to 16; and Ris a monovalent hydrocarbon group having 1 to 20 carbon atoms, in which when n is 2 or more, each of a plurality of Ris an independent monovalent hydrocarbon group having 1 to 20 carbon atoms or the plurality of Rare bonded to one another to constitute an alicyclic structure having 3 to 20 ring members together with a carbon atom or a carbon chain through which the groups are bonded.SELECTED DRAWING: None

Description

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

  Radiation sensitive resin compositions used for fine processing by lithography are far ultraviolet rays such as KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), extreme ultraviolet light (EUV: Extreme Ultraviolet, wavelength 13.5 nm). The acid is generated in the exposed part by irradiation with charged particle beams such as electron beams, and the chemical reaction using this acid as a catalyst causes a difference in the dissolution rate in the developer between the exposed part and the unexposed part. A resist pattern is formed thereon.

  At present, miniaturization of the resist pattern processing technique is being attempted by using a laser beam having a shorter wavelength, an electron beam, an immersion exposure apparatus, or the like. Accordingly, the radiation-sensitive resin composition is required to have excellent lithography performance such as resolution and rectangularity of the cross-sectional shape of the resist pattern. In response to this requirement, the structure of the polymer in the radiation-sensitive resin composition has been studied, and various polar groups have been introduced, and those having a lactone structure are known (Japanese Patent Laid-Open No. 2000). No. 26464, JP 2000-159758 A, JP 10-207069 A, and JP 10-274852 A). According to these radiation-sensitive resin compositions, it is said that resolution can be improved.

JP 2000-26446 A JP 2000-159758 A JP-A-10-207069 JP-A-10-274852

  However, at present, when the miniaturization of the resist pattern is progressing to a level of 45 nm or less, the required level of the above performance is further increased, and further, LWR (Line Width Roughness) performance, CDU (Critical Dimension Uniformity). There is a demand for excellent performance and MEEF (Mask Error Enhancement Factor) performance. However, the above conventional radiation-sensitive resin composition cannot satisfy these requirements.

  The present invention has been made based on the above circumstances, and an object thereof is to provide a radiation-sensitive resin composition having excellent LWR performance, CDU performance, and MEEF performance (hereinafter also referred to as “LWR performance”). And

（式（１）中、Ｒ^１は、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^２は、炭素数１〜２０の１価の炭化水素基である。ｎは、０〜１６の整数である。Ｒ^３は、炭素数１〜２０の１価の炭化水素基であり、ｎが２以上の場合、複数のＲ^３は、それぞれ独立して、炭素数１〜２０の１価の炭化水素基であるか、又は複数のＲ^３が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の脂環構造を構成する。） The invention made in order to solve the above problems includes a first polymer having a first structural unit represented by the following formula (1) (hereinafter also referred to as “[A] polymer”), sulfonic acid or A first radiation-sensitive acid generator that generates disulfonylimide acid (hereinafter also referred to as “[B] radiation-sensitive acid generator”). A radiation-sensitive resin composition having a group containing a ring structure and containing an anion having one or more fluorine atoms.

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms. N is 0. R ³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and when n is 2 or more, the plurality of R ³ are each independently a group having 1 to 20 carbon atoms. It is a monovalent hydrocarbon group, or a plurality of R ³ are combined together to form an alicyclic structure having 3 to 20 ring members together with the carbon atom or carbon chain to which these are bonded.

  Another invention made to solve the above problems includes a step of coating the radiation-sensitive resin composition on one side of the substrate, and a step of exposing the resist film obtained by the coating step. And a step of developing the exposed resist film.

  Here, the “polycyclic structure” in the “group containing a polycyclic structure” refers to a structure containing a plurality of rings when the cyclic structure is a single ring. Examples of the polycyclic structure include (1) a structure including a condensed ring, (2) a structure including a bridged ring, and (3) a structure including any of a condensed ring, a bridged ring, and a single ring. . “Monocycle” refers to a ring consisting of only one ring.

  “Organic group” refers to a group containing at least one carbon atom. The “acid-dissociable group” refers to a group that replaces a hydrogen atom such as a carboxy group or a hydroxy group and dissociates by the action of an acid. “Number of ring members” means the number of atoms constituting the ring of an alicyclic structure, aromatic ring structure, aliphatic heterocyclic structure and aromatic heterocyclic structure, and in the case of polycyclic rings such as fused rings and bridged rings Refers to the total number of atoms constituting this polycycle. For example, the naphthalene structure has 10 ring members and the adamantane structure has 10 ring members.

  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, a resist pattern having excellent LWR performance, CDU performance, and MEEF performance can be formed. Therefore, they can be suitably used for pattern formation in semiconductor device manufacturing or the like where further miniaturization is expected.

<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 has, as a suitable component, a radiation-sensitive acid generator other than [B] acid generator (hereinafter referred to as “[C] radiation-sensitive acid generator” or “[C] acid generator”). And [A] a polymer having a larger mass content of fluorine atoms than the polymer (hereinafter also referred to as “[D] polymer”), [E] a solvent, and [F] a nitrogen-containing compound. You may do it. Furthermore, the said radiation sensitive resin composition may contain the other arbitrary component in the range which does not impair the effect of this invention. The said radiation sensitive resin composition is excellent in LWR performance, CDU performance, and MEEF performance by having the said structure. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a heavy polymer having a structural unit (I) represented by the following formula (1) including a dinorbornane structure in which two norbornanes (bicyclo [2.2.1] heptane) share one side. It is a coalescence. [A] The polymer is usually a base polymer in the radiation-sensitive resin composition. The “base polymer” refers to a polymer having the largest content of the polymers constituting the resist pattern, and preferably occupies 50% by mass or more, more preferably 60% by mass or more.

  [A] In addition to the structural unit (I), the polymer may be a structural unit containing an acid dissociable group (hereinafter also referred to as “structural unit (II)”), a lactone structure, a cyclic carbonate structure, a sultone structure, or the like. A structural unit (hereinafter also referred to as “structural unit (III)”), a structural unit containing a phenolic hydroxyl group (hereinafter also referred to as “structural unit (IV)”), and / or an alcoholic hydroxyl group. It is preferable to have a structural unit (hereinafter also referred to as “structural unit (V)”), and may have other structural units other than the structural units (II) to (V). [A] The polymer may have one or more of these structural units.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group. The structural unit (I) includes a structural unit represented by the following formula (1). According to the radiation-sensitive resin composition, the acid-dissociable group of the structural unit (I) of the exposed portion is dissociated by the acid generated from the [B] acid generator or the like by irradiation with radiation, and the exposed portion and the unexposed portion Thus, a difference in solubility in the developer occurs, and as a result, a resist pattern can be formed.

In said formula (1), R < ¹ > is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms. n is an integer of 0-16. R ³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and when n is 2 or more, the plurality of R ³ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms. Or a plurality of R ³ are combined together to form an alicyclic structure having 3 to 20 ring members together with the carbon atom or carbon chain to which they are bonded.

  The radiation-sensitive resin composition contains the [A] polymer containing the structural unit (I) represented by the above formula (1) and the [B] radiation-sensitive acid generator, thereby exhibiting the above effects. The reason is not necessarily clear, but can be inferred as follows, for example. That is, since the [A] polymer has a structural unit containing a dinorbornane structure, it has a bulky (bulky) structure. [B] Since the radiation-sensitive acid generator also has a group containing a polycyclic structure, it has a bulky structure. As a result, the [A] polymer has a bulky structure, so the dissolution contrast is improved, and the [B] radiation-sensitive acid generator has a bulky structure, so that the acid diffusion length is appropriately shortened. It is considered that LWR performance, CDU performance, etc. of the radiation sensitive resin composition can be improved by these two synergistic effects.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ² and R ³ include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent hydrocarbon group having 3 to 20 carbon atoms. Examples include alicyclic hydrocarbon groups and monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, and an i-propyl 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. Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, and a methyl group, an ethyl group, and an i-propyl group are further preferable.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monovalent monocyclic alicyclic saturated hydrocarbon groups such as a cyclopentyl group and a cyclohexyl group;
Monovalent monocyclic alicyclic unsaturated hydrocarbon groups such as a cyclopentenyl group and a cyclohexenyl group;
Monovalent polycyclic alicyclic saturated hydrocarbon groups such as a norbornyl group, an adamantyl group, a tricyclodecyl group;
And monovalent polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group and a tricyclodecenyl group. Among these, a monovalent monocyclic alicyclic saturated hydrocarbon group and a monovalent polycyclic saturated alicyclic hydrocarbon group are preferable, and a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group are more preferable.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group, methylnaphthyl group, anthryl group, and methylanthryl group;
Examples include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group, and anthrylmethyl group.

Examples of the alicyclic structure having 3 to 20 ring members represented by R ² and R ³ include alicyclic saturated hydrocarbon structures such as a cyclopentane structure and a cyclohexane structure.

As R ² in the above formula (1), the hydrocarbon group of R ² preferably has 3 to 20 carbon atoms, and among these, an i-propyl group is more preferable from the viewpoint of ease of dissociation. .

R ³ in the above formula (1) is preferably a hydrogen atom independently from the viewpoint that the polarity of the [A] polymer can be more easily controlled among them.

  As the structural unit (I) represented by the above formula (1), specifically, structural units represented by the following end formulas (1-1) to (1-2) (hereinafter referred to as structural unit (1) -1) to (1-2)) and exo-type structural units represented by the following formulas (1-3) to (1-4) (hereinafter, structural units (1-3) to (1- 4))).

In the formulas (1-1) to (1-4), R ¹ , R ² and R ³ have the same meaning as the above formula (1).

  As the structural unit (I) represented by the above formula (1), an end-type structural unit (1-1) and a structural unit (1-2) are preferable among them from the viewpoint of improving LWR performance and the like.

  Specific examples of the structural unit (I) represented by the above formula (1) include a structural unit represented by the following formula.

In the formulas (1-a) to (1-g), R ¹ has the same meaning as the formula (1).

  As the structural unit (I) represented by the above formula (1-1), an end-type structural unit (1-a) and a structural unit (1-d) are preferable among these from the viewpoint of improving LWR performance and the like. .

  [A] When the polymer has the structural unit (I), the lower limit of the content ratio of the structural unit (I) is preferably 3 mol% with respect to all the structural units in the polymer [A], and 5 mol%. Is more preferable, and 10 mol% is further more preferable. As an upper limit of the said content rate, 80 mol% is preferable, 75 mol% is more preferable, and 70 mol% is further more preferable. By making the content rate of structural unit (I) into the said range, the [A] polymer can adjust the solubility to a developing solution more appropriately, As a result, LWR of the said radiation sensitive resin composition concerned The performance and the like can be further improved. In addition, the adhesion between the obtained resist pattern and the substrate can be further improved.

[Structural unit (II)]
The structural unit (II) is a structural unit containing an acid dissociable group different from the structural unit (I). The structural unit (II) is not particularly limited as long as it contains an acid dissociable group different from the structural unit (I).

  Examples of the structural unit (II) include structural units represented by the following formula (3) and the following formula (8) (hereinafter also referred to as “structural units (II-1) to (II-2)”). It is done. [A] The polymer may have one or more structural units (II). Hereinafter, the structural unit (II) will be described.

In said formula (3), R ^<A1> is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^A2 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^A3 and R ^A4 each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms, or have 3 to 11 ring members composed of these groups together with the carbon atom to which they are bonded. Represents the ring structure of

In said formula (8), R ^<A1> is synonymous with said formula (3). L ^p is a single bond, —COO— or —CONH—. R ^m represents a monovalent organic group having 1 to 20 carbon atoms. c is an integer of 0-4. When c is 2 or more, the plurality of R ^m may be the same or different. R ^A5 , R ^A6 and R ^A7 are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms.

R ^A1 is preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (II).

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^A2 , R ^A3 and R ^A4 include, for example, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and 1 to 3 carbon atoms. Valent alicyclic hydrocarbon group, monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and the like.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, and an i-propyl 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. Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, a methyl group, an ethyl group, and an i-propyl group are further preferable, and an ethyl group is particularly preferable.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monovalent monocyclic alicyclic saturated hydrocarbon groups such as a cyclopentyl group and a cyclohexyl group;
Monovalent monocyclic alicyclic unsaturated hydrocarbon groups such as a cyclopentenyl group and a cyclohexenyl group;
Monovalent polycyclic alicyclic saturated hydrocarbon groups such as a norbornyl group, an adamantyl group, a tricyclodecyl group;
And monovalent polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group and a tricyclodecenyl group. Among these, a monovalent monocyclic alicyclic saturated hydrocarbon group and a monovalent polycyclic saturated alicyclic hydrocarbon group are preferable, and a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group are more preferable.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group, methylnaphthyl group, anthryl group, and methylanthryl group;
Examples include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group, and anthrylmethyl group.

Examples of the alicyclic structure having 3 to 11 ring members composed of R ^A3 and R ^A4 together with the carbon atom to which they are bonded include a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a norbornane structure, and an adamantane. Alicyclic structures such as structures;
Examples thereof include aliphatic heterocyclic structures such as an oxacyclopentane structure, a thiacyclopentane structure, and an azacyclopentane structure. Among these, an alicyclic structure is preferable and a cyclohexane structure is more preferable.

  As the structural unit (II), for example, structural units represented by the following formulas (3-1) to (3-5) and (8-1) (hereinafter referred to as “structural units (II-1-1) to (II) -1-5) and (II-2-1) ").

In the above formulas (3-1) to (3-5), R ^{A1 to} R ^A4 have the same meaning as the above formula (3).
In said formula (3-1), i is an integer of 1-4.
In said formula (3-3), j is an integer of 1-4.
In the above formula (3-5), R ^{A2 ′} , R ^{A3 ′} and R ^{A4 ′} each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms.
In said formula (8-1), R ^{<A1 >} , R ^{< A5>} , R ^<A6> and R ^<A7> are synonymous with said formula (8).

  As i and j, 1-3 are preferable and 1 and 2 are more preferable.

  As the structural unit (II), structural units (II-1-1) to (II-1-5) are preferable.

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

In the above formula, R ^A1 has the same ^meaning as the above formula (3).

  As the structural unit (II), a structural unit derived from 1-alkyl-monocyclic cycloalkane-1-yl (meth) acrylate, a structure derived from 2-alkyl-polycyclic cycloalkane-2-yl (meth) acrylate A structural unit derived from a unit and 2- (cycloalkane-yl) propan-2-yl (meth) acrylate, preferably a structural unit derived from 1-i-propylcyclopentan-1-yl (meth) acrylate, 1- Structural units derived from methylcyclohexane-1-yl (meth) acrylate, structural units derived from 2-ethyl-adamantan-2-yl (meth) acrylate, 2-ethyl-tetracyclododecan-2-yl (meth) acrylate Unit derived from 2-, adamantane-1-yl) propan-2-yl (meth) acrylate A structural unit derived from and 2- (cyclohexane-1-yl) propan-2-yl (meth) structural units derived from acrylate are more preferred.

  As a minimum of the content rate of structural unit (II), 5 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 10 mol% is more preferable, 20 mol% is further more preferable, 30 mol % Is particularly preferred. As an upper limit of the said content rate, 80 mol% is preferable, 75 mol% is more preferable, 70 mol% is further more preferable, 60 mol% is especially preferable. By making the content rate of structural unit (II) into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved further.

[Structural unit (III)]
The structural unit (III) is a structural unit including a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. [A] In addition to the structural unit (I) and the structural unit (II), the polymer can further adjust the solubility in the developer more appropriately by further including the structural unit (III). The LWR performance etc. of the said radiation sensitive resin composition can be improved more. 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 (III) 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.

  As the structural unit (III), a structural unit having a lactone structure, a structural unit having a cyclic carbonate structure, and a structural unit having a sultone structure are preferable. A structural unit derived from a lactone structure-containing (meth) acrylate, a cyclic carbonate structure-containing ( More preferred are structural units derived from (meth) acrylate and structural units derived from sultone structure-containing (meth) acrylate, derived from norbornanelactone-yl (meth) acrylate, derived from cyanonorbornanelactone-yl (meth) acrylate Structural units derived from norbornanelactone-yloxycarbonylmethyl (meth) acrylate, structural units derived from γ-butyrolactone-yl (meth) acrylate, ethylene carbonate-ylmethyl (meth) acrylate Structural units and norbornane sultone derived from over bets - yl (meth) structural units derived from acrylate are more preferred.

  [A] When the polymer has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 10 mol%, preferably 15 mol% with respect to all the structural units in the polymer. Is more preferable, 20 mol% is further more preferable, and 25 mol% is particularly preferable. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, 60 mol% is further more preferable, 55 mol% is especially preferable. By making the content rate of structural unit (III) into the said range, the [A] polymer can adjust the solubility to a developing solution more appropriately, As a result, LWR of the said radiation sensitive resin composition concerned The performance and the like can be further improved. In addition, the adhesion between the obtained resist pattern and the substrate can be further improved.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing a phenolic hydroxyl group. When KrF excimer laser light, EUV, electron beam, or the like is used as the radiation to be irradiated in the exposure process in the resist pattern forming method, the sensitivity is further enhanced by having the structural unit (IV) in the polymer [A]. Can do.

  Examples of the structural unit (IV) include a structural unit represented by the following formula (4) (hereinafter also referred to as “structural unit (IV)”).

In the formula ^{(4), R 14} is a hydrogen atom or a methyl group. R ¹⁵ is a monovalent organic group having 1 to 20 carbon atoms. p is an integer of 0-3. When p is 2 or 3, the plurality of R ¹⁵ may be the same or different. q is an integer of 1 to 3. However, p + q is 5 or less.

R ¹⁴ is preferably a hydrogen atom from the viewpoint of the copolymerizability of the monomer giving the structural unit (IV).

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ¹⁵ 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 (g) containing a divalent heteroatom-containing group, a group obtained by substituting part or all of the hydrogen atoms of the hydrocarbon group and group (g) with a heteroatom-containing group, and the like.

  As said p, the integer of 0-2 is preferable, 0 and 1 are more preferable, and 0 is further more preferable.

  As said q, 1 and 2 are preferable and 1 is more preferable.

  Examples of the structural unit (IV) include structural units represented by the following formulas (4-1) to (4-4) (hereinafter also referred to as “structural units (IV-1) to (IV-4)”). Etc.

In the above formulas (4-1) to (4-4), R ¹⁴ has the same meaning as the above formula (4).

  As the structural unit (IV), the structural unit (IV-1) and the structural unit (IV-2) are preferable, and the structural unit (IV-1) is more preferable.

  [A] When a polymer has a structural unit (IV), as a minimum of the content rate of a structural unit (IV), 10 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 20 More preferably, mol% is more preferable, 30 mol% is further more preferable, and 35 mol% is especially preferable. As an upper limit of the said content rate, 90 mol% is preferable, 80 mol% is more preferable, 75 mol% is further more preferable, 70 mol% is especially preferable. By making the content rate of structural unit (IV) into the said range, the said radiation sensitive resin composition can further improve a sensitivity.

  The structural unit (IV) is formed by polymerizing a styrene monomer having an acyloxy group such as an acetoxy group, and then performing a hydrolysis reaction in the presence of a base such as an amine. can do.

[Structural unit (V)]
The structural unit (V) is a structural unit containing an alcoholic hydroxyl group. [A] By having the structural unit (V), the polymer can adjust the solubility in the developer more appropriately. As a result, the LWR performance of the radiation-sensitive resin composition is further improved. Can be made. In addition, the adhesion of the resist pattern to the substrate can be further improved.

  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.

  As the structural unit (V), a structural unit containing a hydroxyadamantyl group is preferable, and a structural unit derived from 3-hydroxyadamantyl (meth) acrylate is more preferable.

  [A] When a polymer has a structural unit (V), as a minimum of the content rate of a structural unit (V), 2 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 5 The mol% is more preferable, and 8 mol% is more preferable. As an upper limit of the said content rate, 70 mol% is preferable, 60 mol% is more preferable, and 55 mol% is further more preferable. By making the content rate of a structural unit (V) into the said range, the [A] polymer can adjust the solubility to a developing solution further moderately, As a result, LWR of the said radiation sensitive resin composition is obtained. The performance and the like can be further improved. In addition, the adhesion of the resist pattern to the substrate can be further enhanced.

[Other structural units]
[A] The polymer may have other structural units in addition to the structural units (I) to (V). Examples of the other structural unit include a structural unit containing a ketonic carbonyl group, a cyano group, a carboxy group, a nitro group, an amino group or a combination thereof, and a non-dissociable monovalent alicyclic hydrocarbon group ( And structural units derived from (meth) acrylic acid esters. As an upper limit of the content rate of another structural unit, 20 mol% is preferable with respect to all the structural units which comprise a [A] polymer, and 10 mol% is more preferable.

  [A] As a minimum of content of a polymer, 55 mass% is preferred to 60 mass%, and 65 mass% is still more preferred to the total solid of the radiation sensitive resin composition concerned. “Total solid content” refers to the sum of components other than the solvent [E] in the radiation-sensitive resin composition. The radiation sensitive resin composition may contain one or more [A] polymers.

<[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-cyclopropyl). Azo radical initiators such as propionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate;
And peroxide radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, and the like. Of these, AIBN and dimethyl 2,2′-azobisisobutyrate are preferred, and AIBN is more preferred. These radical polymerization initiators can be used alone or in combination of two or more.

Examples of the solvent used for polymerization include saturated hydrocarbons such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloaliphatic saturated hydrocarbons such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutane, bromohexane, dichloroethane, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate;
Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples 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.

  As a minimum of reaction temperature in superposition | polymerization, 40 degreeC is preferable and 50 degreeC is more preferable. 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 superposition | polymerization, 1 hour is preferable and 2 hours is more preferable. The upper limit of the reaction time is preferably 48 hours, more preferably 24 hours.

  [A] The lower limit of the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is preferably 1,000, more preferably 3,000, still more preferably 4,000, 000 is particularly preferred. 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 of the said radiation sensitive resin composition improves, and development defect inhibitory property improves more.

  [A] The lower limit of the ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is usually 1 and preferably 1.1. As an upper limit of the ratio, 5 is preferable, 3 is more preferable, and 2 is more preferable.

<[B] Radiation sensitive acid generator>
The radiation-sensitive resin composition contains a [B] acid generator in addition to the [A] polymer. [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 with the radiation resin composition. As the containing form of the acid generator in the radiation sensitive resin composition, in the form of a free compound (hereinafter referred to as “[B] acid generator” as appropriate), or in a form incorporated as a part of the polymer, Both of these forms may be used.

[B] The acid generator generates sulfonic acid or disulfonylimide acid. [B] The acid generator includes a group having a polycyclic structure and an anion having one or more fluorine atoms. [B] The anion of the acid generator has —SO ₂ — and a carbon atom adjacent to the sulfur atom of this —SO ₂ —, and one or more fluorine atoms are bonded to this carbon atom. It is preferable.

  As described above, the polycyclic structure of the [B] acid generator includes (1) a structure containing a condensed ring, (2) a structure containing a bridged ring, (3) a condensed ring, a bridged ring and a single ring. Among them, (1) a structure containing a condensed ring or (2) a structure containing a bridged ring is preferable, and (2) a structure containing a bridged ring is more preferable.

  [B] Examples of the acid generator include onium salt compounds and disulfonylimide salt compounds.

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

  [B] The acid generator is preferably an acid generator represented by the following formula (r1) or the following formula (r2). [B] When the acid generator has the following structure, the diffusion length of the acid generated by exposure in the resist film is appropriately shortened due to the interaction between the polymer and the structural unit (II), etc. As a result, the LWR performance and the depth of focus of the radiation sensitive resin composition can be further improved.

In the above formula (r1), R ^p1 is an organic group containing a monovalent polycyclic structure having 5 to 20 carbon atoms. 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 hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a fluorine atom, and R ^p5 and R of the carbon atom adjacent to the sulfur atom of —SO ₂ —. ^At least one of ^p6 is a fluorine atom. 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. T ⁺ is a monovalent radiation-sensitive onium cation.

In the formula (r2), R ^p7 and R ^p8 are each independently a monovalent organic group having 1 to 20 carbon atoms, and at least one of —SO ₂ — in R ^p7 and R ^p8 One or more fluorine atoms are bonded to a carbon atom adjacent to the sulfur atom, and at least one of R ^p7 and R ^p8 has a group containing a polycyclic structure.

Examples of the group containing a monovalent polycyclic structure represented by R ^p1 , R ^p7 and R ^p8 include (1) a monovalent group having a structure containing a condensed ring having 7 or more ring members, (2) One of a monovalent group having a structure including a bridge ring having 7 or more ring members, (3) a condensed ring having 7 or more ring members, a bridge ring having 7 or more ring members, or a single ring having 5 or more ring members And a monovalent group having a structure containing a plurality of. Among these, a monovalent group having a structure containing a condensed ring having 7 or more ring members or a monovalent group having a structure containing a bridged ring having 7 or more ring members is preferable, and a bridged ring having 7 or more ring members is preferable. A monovalent group having a structure to be included is more preferable.

Examples of the condensed ring having 7 or more ring members include:
Condensed ring hydrocarbon structures such as tricyclodecane, tetracyclododecane, tricyclodecene, dinorbornane;
Polycyclic aliphatic heterocyclic structures such as oxaspirodecane polycyclic aromatic ring structures such as naphthalene, phenanthrene, anthracene;
Examples thereof include polycyclic aromatic heterocyclic structures such as benzopyran and indole.

As a bridge ring having 7 or more ring members, for example,
Bridged ring hydrocarbon structures such as norbornane, adamantane, norbornene;
Examples thereof include polycyclic aliphatic heterocyclic structures such as norbornane lactone, norbornane sultone, oxanorbornane, diazabicyclooctane, and thianorbornane.

Examples of the monocyclic ring having 5 or more ring members include monocyclic alicyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cyclododecane, cyclopentene, cyclohexene, cycloheptene, cyclooctene, and cyclodecene. Construction;
Monocyclic aliphatic heterocyclic structures such as hexanolactone, hexanosultone, oxacycloheptane, cyclic acetal, azacyclohexane and thiacyclohexane;
Monocyclic aromatic ring structures such as benzene;
And monocyclic aromatic heterocyclic structures such as furan, pyran, pyridine, and pyrimidine.

As a minimum of the number of ring members of the ring structure which constitutes the polycyclic structure of R ^p1 , R ^p7 and R ^p8 , 6 is preferable, 7 is more preferable, 8 is further preferable, and 9 is particularly preferable. 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.

The condensed ring, bridged ring or monocyclic structure constituting the group containing a polycyclic structure represented by R ^p1 , R ^p7 and R ^p8 includes Z-1, Z-2, Z-3 and Z-4. Are preferred, and Z-1 and Z-2 are more preferred.

Moreover, one part or all part of the hydrogen atom which the polycyclic structure of R ^{< p1>} , R ^<p7> and R ^<p8> has may be substituted by the 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 and other heteroatom-containing groups.

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.

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

The n ^p2, preferably an integer of 0 to 5, more preferably an integer of 0 to 2, more preferably 0 and 1, 0 being particularly preferred.

As ^np3 , the integer of 1-5 is preferable, the integer of 1-4 is more preferable, the integer of 1-3 is more preferable, and 1 and 2 are especially preferable.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^p7 and R ^p8 include the same groups as those exemplified as R ^{15 in the} above formula (4).

The monovalent radiation-sensitive onium cation represented by T ⁺ is a cation that is decomposed by exposure light and / or electron beam irradiation. Taking an acid generator composed of a sulfonate anion and a radiation-sensitive onium cation as an example, in the exposed portion, a sulfonic acid is generated from protons generated by the decomposition of the radiation-sensitive onium cation and the sulfonate anion.
Examples of the monovalent radiation-sensitive onium cation represented by T ⁺ include a cation represented by the following formula (r-a) (hereinafter also referred to as “cation (r-a)”), and the following formula ( cation represented by rb) (hereinafter also referred to as “cation (rb)”) and cation represented by the following formula (rc) (hereinafter also referred to as “cation (rc)”). Etc.).

In the above formula (r-a), R ^B3 and R ^B4 are each independently a monovalent organic group having 1 to 20 carbon atoms. R ^B5 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. b3 is an integer of 0-5 each independently. If R ^B5 is plural, the plurality of R ^B5 may be the same or different, and the plurality of R ^B5, may constitute a keyed ring structure. n _bb is an integer of 0 to 3.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^B3 , R ^B4, and R ^B5 include, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a carbon-carbon gap of the hydrocarbon group. Alternatively, a monovalent group (g) containing a divalent heteroatom-containing group at the terminal end on the bond side, a part or all of the hydrogen atoms of the hydrocarbon group and group (g) were substituted with a heteroatom-containing group. And monovalent groups.

R ^B3 and R ^B4 are preferably a monovalent unsubstituted hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group in which a hydrogen atom is substituted with a substituent, and a monovalent unsubstituted group having 6 to 18 carbon atoms. Are more preferable, and an aromatic hydrocarbon group in which a hydrogen atom is substituted with a substituent is more preferable, and a phenyl group is more preferable.

Examples of the substituent which may be substituted for the hydrogen atom contained in the monovalent hydrocarbon group having 1 to 20 carbon atoms represented as R ^B3 and R ^B4 above are substituted or unsubstituted 1 to 1 carbon atoms having 1 to 20 carbon atoms. valent hydrocarbon _{^{group, -OSO 2 -R k, -SO 2}} -R k, -OR k, -COOR k, -O-CO-R k, -O-R kk -COOR k, -R kk -CO -R ^k and ^{-S-R k} are preferred. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

As R ^B5 , a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, —OSO ₂ —R ^k , —SO ₂ —R ^k , —OR ^k , —COOR ^k , —O—CO— R ^k , —O—R ^kk —COOR ^k , —R ^kk —CO—R ^k and —S—R ^k are preferred. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

In the above formula (rb), R ^B6 and R ^B7 are each independently a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. b4 is an integer of 0-7. If R ^B6 is plural, the plurality of R ^B6 may be the same or different, and plural R ^B6 may constitute The combined ring structure. b5 is an integer of 0-6. If R ^B7 is plural, R ^B7 may be the same or different, and plural R ^B7 may constitute The combined 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.

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

In the above formula (rc), R ^B9 and R ^B10 are each independently a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. b6 and b7 are each independently an integer of 0 to 5. If R ^B9 is plural, plural R ^B9 may be the same or different, and plural R ^B9 may constitute The combined ring structure. If R ^B10 is plural, R ^B10 may be the same or different, and plural R ^B10 may constitute a keyed ring structure.

As R ^B9 and R ^B10 , a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, —OSO ₂ —R ^k , —SO ₂ —R ^k , —OR ^k , —COOR ^k , — Two or more of O—R ^k —, —O—CO—R ^k , —O—R ^kk —COOR ^k , —R ^kk —CO—R ^k , —S—R ^k and these groups are combined with each other. The ring structure constituted is preferable. R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^B5 , R ^B6 , R ^B7 , R ^B9, and R ^B10 include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. A linear alkyl group of
branched alkyl groups such as i-propyl group, i-butyl group, sec-butyl group, t-butyl group;
Aryl groups such as phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group;
Examples include aralkyl groups such as benzyl group and phenethyl group.

Examples of the divalent organic group represented by R ^B8 include one hydrogen from the monovalent organic group having 1 to 20 carbon atoms exemplified as R ^B3 , R ^B4 and R ^{B5 in the} above formula (r−a). Examples include groups other than atoms.

Examples of the substituent that may substitute the hydrogen atom of the hydrocarbon group represented by R ^B5 , R ^B6 , R ^B7 , R ^B9, and R ^B10 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. And a halogen atom such as hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, and acyloxy group. Among these, a halogen atom is preferable and a fluorine atom is more preferable.

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

As b3 in Formula (r-a), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is more preferable. As n _bb , 0 and 1 are preferable, and 0 is more preferable. As b4 in the formula (rb), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is more preferable. As b5, the integer of 0-2 is preferable, 0 and 1 are more preferable, and 0 is still more preferable. As _nb2 , 2 and 3 are preferable and 2 is more preferable. As _nb1 , 0 and 1 are preferable and 0 is more preferable. As b6 and b7 in Formula (rc), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is more preferable.

Of these, cation (r−a) and cation (r−b) are preferable as T ⁺ , and 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 (r1) include compounds represented by the following formulas (r1-1) to (r1-16) (hereinafter, “compounds (r1-1) to (r1-16)”). Or the like)).

In the above formulas (r1-1) to (r1-16), T ⁺ is a monovalent radiation-sensitive onium cation.

  Examples of the acid generator represented by the above formula (r2) include a compound represented by the following formula (r2-1) (hereinafter also referred to as “compound (r2-1)”).

In the above formula (r2-1), T ⁺ is a monovalent radiation-sensitive onium cation.

  [B] As the acid generator, compounds (r1-1), (r1-4), (r1-8) and (r1-13) are preferable.

  [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, 35 mass parts is preferable, 30 mass parts is more preferable, and 25 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] Radiation sensitive acid generator>
The said radiation sensitive resin composition may contain a [C] radiation sensitive acid generator as needed. [C] In the radiation sensitive acid generator, the acidity of the acid generated is lower than the acidity of the acid generated by the [B] radiation sensitive acid generator. [C] The radiation-sensitive acid generator generates a weak acid upon exposure. [A] When the acid dissociable group contained in the polymer is also dissociated by the weak acid generated from the [C] radiation sensitive acid generator, [B] the radiation sensitive acid generator and [C] radiation sensitive By using the acidic acid generator in combination, the concentration distribution of the acid generated in the resist film can be appropriately adjusted as compared with the case where only one of them is used, and LWR and CDU can be improved. On the other hand, when the acid dissociable group contained in the [A] polymer is not dissociated by the weak acid generated from the [C] radiation sensitive acid generator, the [C] radiation sensitive acid generator is [B] sensitive. The acid generated from the radioactive acid generator is captured, and the diffusion phenomenon of the acid generated from the following [B] acid generator in the resist film by exposure is controlled. At this time, the [C] radiation-sensitive generator also generates a weak acid by the action of radiation in the exposed region, so that [B] the acid generated from the radiation-sensitive acid generator is not captured and the [A] polymer is formed. It does not inhibit the dissociation of the acid dissociable groups contained. As a result, the [C] acid generator has an effect as an acid diffusion control agent that suppresses an undesirable chemical reaction in the non-exposed region. [C] The content of the radiation-sensitive acid generator in the radiation-sensitive resin composition may be a free compound (hereinafter, referred to as “[C] acid generator” as appropriate) as a part of the polymer. Either the built-in form or both forms may be used.

  [C] Examples of the radiation sensitive acid generator include an onium salt compound which decomposes by exposure and loses acid diffusion controllability. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (6-1), an iodonium salt compound represented by the following formula (6-2), and the like.

In the above formula ^{(6-1), R 23} and ^{R 24} are each independently a monovalent organic group having 1 to 20 carbon atoms. R ³⁰ is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, a nitro group, or a halogen atom. b8 is an integer of 0-5 each independently. If R ³⁰ is plural, plural R ³⁰ may be the same or different, and plural R ³⁰ may constitute a keyed ring structure. n _b3 is an integer of 0 to 3.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ²³ , R ²⁴ and R ³⁰ include, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a carbon-carbon gap of the hydrocarbon group. Or a group (g) containing a divalent heteroatom-containing group at the terminal end of the bond, a group in which part or all of the hydrogen atoms of the hydrocarbon group and group (g) are substituted with a heteroatom-containing group, etc. Can be mentioned.

R ²³ and R ²⁴ are preferably a monovalent unsubstituted hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group in which a hydrogen atom is substituted with a substituent, and a monovalent unsubstituted group having 6 to 18 carbon atoms. Are more preferable, and an aromatic hydrocarbon group in which a hydrogen atom is substituted with a substituent is more preferable, and a phenyl group is more preferable.

Examples of the substituent which may be substituted for the hydrogen atom contained in the monovalent hydrocarbon group having 1 to 20 carbon atoms represented as R ²³ and R ²⁴ are substituted or unsubstituted 1 to 1 carbon atoms having 1 to 20 carbon atoms. valent hydrocarbon _{^{group, -OSO 2 -R q, -SO 2}} -R q, -OR q, -COOR q, -O-CO-R q, -O-R qq -COOR q, -R qq -CO -R ^q and ^{-S-R q} are preferred. R ^q is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^qq is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

R ³⁰ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, —OSO ₂ —R ^q , —SO ₂ —R ^q , —OR ^q , —COOR ^q , —O—CO—. ^{R q, -O-R qq -COOR} q, -R qq -CO-R q and ^{-S-R q} are preferred. R ^q is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^qq is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

In said formula (6-2), R < ²⁶ > -R < ²⁷ > is respectively independently a C1-C20 monovalent organic group, a hydroxyl group, a nitro group, or a halogen atom.

R ²⁶ and R ²⁷ are a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, —OSO ₂ —R ^q , —SO ₂ —R ^q , —OR ^q , —COOR ^q , — A ring structure in which two or more of these groups are combined with each other: O—C—R ^q , —O—R ^qq —COOR ^q , —R ^qq —CO—R ^q , —S—R ^q preferable. R ^q is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^qq is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ³⁰ , R ²⁶ and R ²⁷ include the same groups as those exemplified as R ^{B5 in} the above formula (r−a). .

Examples of the substituent that may substitute the hydrogen atom of the hydrocarbon group represented by R ³⁰ , R ^26, and R ²⁷ are the same as those exemplified as R ^{B5 in} the above formula (r−a). Etc.

R ³⁰ , R ²⁶ and R ²⁷ R ^B9 and R ^B10 include an unsubstituted linear or branched monovalent alkyl group, a monovalent fluorinated alkyl group, and an unsubstituted monovalent aromatic carbonization. A hydrogen group, —OSO ₂ —R ^q and —SO ₂ —R ^q are preferred, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferred, and a fluorinated alkyl group is more preferred.

In the above formulas (6-1) and (6-2), E ⁻ and Q ⁻ are each independently OH ⁻ , R ^β —COO ⁻ , R ^γ —SO ₃ ^— or the following formula (6-3) An anion represented by ^Rβ is an alkyl group, an aryl group, or an aralkyl group. R ^γ is an alkyl group or an aralkyl group.

In the above formula (6-3), R ²⁸ represents a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched fluorinated alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. -12 linear or branched alkoxy groups. u is an integer of 0-2. When u is 2, two R ²⁸ may be the same or different.

  [C] Examples of the radiation sensitive acid generator include compounds represented by the following formulas.

  [C] Among these, the radiation-sensitive acid generator is preferably a sulfonate, more preferably a triarylsulfonate, and even more preferably triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate.

  When the said radiation sensitive resin composition contains a [C] radiation sensitive acid generator, as a minimum of content of a [C] radiation sensitive acid generator, with respect to 100 mass parts of [A] polymers, 0.01 mass part is preferable, 0.1 mass part is more preferable, and 0.5 mass part is further more preferable. The upper limit of the content is preferably 30 parts by mass, more preferably 20 parts by mass, and still more preferably 10 parts by mass with respect to 100 parts by mass of the [A] polymer. When the content of the other acid diffusion controller exceeds the upper limit, the sensitivity of the radiation sensitive resin composition may be lowered.

<[D] Polymer>
[D] The polymer is a polymer having a larger mass content of fluorine atoms than the [A] polymer.
A polymer having a higher hydrophobicity than a polymer serving as a base polymer tends to be unevenly distributed in the resist film surface layer, and the [D] polymer has a higher mass content of fluorine atoms than the [A] polymer. Due to the characteristics resulting from the hydrophobicity, there is a tendency to be unevenly distributed on the surface of the resist film. As a result, according to the radiation sensitive resin composition, it is possible to suppress the elution of the acid generator, the acid diffusion control agent, and the like during the immersion exposure into the immersion medium. In addition, according to the radiation sensitive resin composition, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range due to the properties resulting from the hydrophobicity of the [D] polymer, and bubble defects can be controlled. Generation can be suppressed. Furthermore, according to the radiation-sensitive resin composition, 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. The radiation-sensitive resin composition can form a resist film suitable for the immersion exposure method by containing the [D] polymer as described above.

[D] The lower limit of the mass content of fluorine atoms in the polymer is preferably 1% by mass, more preferably 2% by mass, and even more preferably 3% by mass. As an upper limit of the said mass content rate, 60 mass% is preferable, 50 mass% is more preferable, and 40 mass% is further more preferable. By making the mass content rate of a fluorine atom into the said range, [D] uneven distribution in the resist film of a polymer can be adjusted more appropriately. The mass content of fluorine atoms in the polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR spectrum measurement.

  [D] The fluorine atom content in the polymer is not particularly limited, and may be bonded to any of the main chain, side chain, and terminal, but is a structural unit containing a fluorine atom (hereinafter, “structural unit (f)”) It is also preferable to have a. [D] In addition to the structural unit (f), the polymer preferably has a structural unit containing an acid-dissociable group from the viewpoint of improving development defect suppression of the radiation-sensitive resin composition. Examples of the structural unit containing an acid dissociable group include the structural unit (II) in the [A] polymer.

  [D] The polymer preferably has an alkali dissociable group. [D] When the polymer has an alkali-dissociable group, the resist film surface can be effectively changed from hydrophobic to hydrophilic during alkali development, and the development defect suppression of the radiation-sensitive resin composition is further improved. To do. The “alkali dissociable group” is a group that replaces a hydrogen atom such as a carboxy group or a hydroxy group, and dissociates in an alkaline aqueous solution (for example, an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C.). Refers to the group.

  As the structural unit (f), a structural unit represented by the following formula (f-1) (hereinafter also referred to as “structural unit (f-1)”) and a structure represented by the following formula (f-2) A unit (hereinafter also referred to as “structural unit (f-2)”) is preferred. The structural unit (f) may have one or more structural units (f-1) and structural units (f-2).

[Structural unit (f-1)]
The structural unit (f-1) is a structural unit represented by the following formula (f-1). [D] A polymer can adjust the mass content of a fluorine atom by having a structural unit (f-1).

In said formula (f-1), ^RJ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, —COO—, —SO ₂ NH—, —CONH— or —OCONH—. R ^K is a monovalent fluorine-cycloaliphatic hydrocarbon group having a monovalent fluorinated chain hydrocarbon group or a 4 to 20 carbon atoms having 1 to 6 carbon atoms.

R ^J 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 (f-1).

As the _{G, -COO -, - SO 2} NH -, - CONH- and -OCONH- are preferred, -COO- is more preferable.

Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by R ^K, some or all of the hydrogen atoms is a linear or branched having 1 to 6 carbon atoms which is substituted by fluorine atoms A chain alkyl group.

The monovalent fluorine-cycloaliphatic hydrocarbon group having 4 to 20 carbon atoms represented by R ^K, monocyclic been 4 to 20 carbon atoms substituted some or all of the hydrogen atoms by fluorine atoms or A polycyclic hydrocarbon group is mentioned.

The R ^K, preferably a fluorinated chain hydrocarbon group, a 2,2,2-trifluoroethyl group and 1,1,1,3,3,3-hexafluoro-2-propyl group is more preferred, 2 2,2-trifluoroethyl group is more preferable.

  [D] When a polymer has a structural unit (f-1), as a minimum of the content rate of a structural unit (f-1), it is 10 mol% with respect to all the structural units which comprise a [D] polymer. Is preferable, and 20 mol% is more preferable. As an upper limit of the said content rate, 100 mol% is preferable and 90 mol% is more preferable. By making the content rate of a structural unit (f-1) into the said range, the mass content rate of the fluorine atom of a [D] polymer can be adjusted further appropriately.

[Structural unit (f-2)]
The structural unit (f-2) is represented by the following formula (f-2). [D] Since the polymer has the structural unit (f-2), the solubility in an alkaline developer is improved, and the occurrence of development defects can be suppressed.

The structural unit (f-2) includes (x) an alkali-soluble group, and (y) a group (hereinafter simply referred to as an “alkali-dissociable group” which dissociates due to the action of an alkali and increases the solubility in an alkali developer. It is also divided into two cases. Common to both (x) and (y), in formula (f-2), R ^C represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^D is a single bond, a (s + 1) -valent hydrocarbon group having 1 to 20 carbon atoms, an oxygen atom, a sulfur atom, —NR ^dd —, a carbonyl group, —COO—, or a terminal on the R ^E side of this hydrocarbon group It is a structure in which —CONH— is bonded, or a structure in which a part of the hydrogen atoms of the hydrocarbon group is substituted with an organic group having a hetero atom. R ^dd is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s is an integer of 1 to 3. However, when s is 1, ^RD is not a single bond.

When the structural unit (f-2) has (x) an alkali-soluble group, R ^F is a hydrogen atom, and A ¹ is an oxygen atom, —COO— * or —SO ₂ O— *. * Indicates a site that binds to R ^F. W ¹ is a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. When A ¹ is an oxygen atom, W ¹ is a fluorinated hydrocarbon group having a fluorine atom or a fluoroalkyl group on the carbon atom to which A ¹ is bonded. R ^E is a single bond or a divalent organic group having 1 to 20 carbon atoms. When s is 2 or 3, a plurality of R ^E , W ¹ , A ¹ and R ^F may be the same or different. When the structural unit (f-2) has (x) an alkali-soluble group, the affinity for an alkali developer can be increased and development defects can be suppressed. (X) As the structural unit (f-2) having an alkali-soluble group, A ¹ is an oxygen atom and W ¹ is a 1,1,1,3,3,3-hexafluoro-2,2-propanediyl group. Is particularly preferred.

When the structural unit (f-2) has (y) an alkali dissociable group, R ^F is a monovalent organic group having 1 to 30 carbon atoms, A ¹ is an oxygen atom, —NR ^aa —, —COO—. * or _-SO 2 O- *. R ^aa is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * Indicates a site that binds to R ^F. W ¹ is a single bond or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ^E is a single bond or a divalent organic group having 1 to 20 carbon atoms. When A ¹ is —COO— * or —SO ₂ O— *, W ¹ or R ^F has a fluorine atom on the carbon atom bonded to A ¹ or the carbon atom adjacent thereto. When A ¹ is an oxygen atom, W ¹ and R ^E are single bonds, R ^D is a structure in which a carbonyl group is bonded to a terminal on the R ^E side of a hydrocarbon group having 1 to 20 carbon atoms, ^F is an organic group having a fluorine atom. When s is 2 or 3, a plurality of R ^E , W ¹ , A ¹ and R ^F may be the same or different. When the structural unit (f-2) has (y) an alkali-dissociable group, the resist film surface changes from hydrophobic to hydrophilic in the alkali development step. As a result, the affinity for the developer can be greatly increased and development defects can be more efficiently suppressed. (Y) As the structural unit (f-2) having an alkali dissociable group, it is particularly preferable that A ¹ is —COO— *, and R ^F or W ¹ or both have a fluorine atom.

As R ^C , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable from the viewpoint of the copolymerizability of the monomer giving the structural unit (f-2).

When R ^E is a divalent organic group, a group having a lactone structure is preferable, a group having a polycyclic lactone structure is more preferable, and a group having a norbornane lactone structure is more preferable.

  [D] When a polymer has a structural unit (f-2), as a minimum of the content rate of a structural unit (f-2), it is 0 mol% with respect to all the structural units which comprise a [D] polymer. Is preferable, and 5 mol% is more preferable. As an upper limit of the said content rate, 50 mol% is preferable and 40 mol% is more preferable. By setting the content ratio of the structural unit (f-2) in the above range, the surface of the resist film formed from the radiation-sensitive resin composition can be more appropriately changed from water repellency to hydrophilicity before and after alkali development. .

  As a minimum of the content rate of a structural unit (f), 10 mol% is preferable with respect to all the structural units which comprise a [D] polymer, 20 mol% is more preferable, and 25 mol% is further more preferable. As an upper limit of the said content rate, 100 mol% is preferable, 90 mol% is more preferable, and 80 mol% is further more preferable.

  [D] The lower limit of the structural unit containing an acid dissociable group in the polymer is preferably 10 mol%, more preferably 20 mol%, and more preferably 25 mol% with respect to all structural units constituting the [D] polymer. Is more preferable. As an upper limit of the said content rate, 90 mol% is preferable, 80 mol% is more preferable, and 75 mol% is further more preferable. By making the content rate of the structural unit containing an acid dissociable group into the said range, the development defect inhibitory property of the said radiation sensitive resin composition can further be improved.

  When the said radiation sensitive resin composition contains a [D] polymer, as a minimum of content of a [D] polymer, 0.1 mass part is preferable with respect to 100 mass parts of [A] polymers. 0.5 parts by mass is more preferable, 1 part by mass is further preferable, and 2 parts by mass is particularly preferable. As an upper limit of the said content, 30 mass parts is preferable, 20 mass parts is more preferable, 15 mass parts is further more preferable, and 10 mass parts is especially preferable. The radiation sensitive resin composition may contain one or more [D] polymers.

  The [D] polymer can be synthesized by the same method as the above-described [A] polymer.

  [D] The lower limit of Mw by GPC of the polymer is preferably 1,000, more preferably 3,000, still more preferably 4,000, and particularly preferably 5,000. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000. [D] 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.

  [D] The lower limit of the ratio of Mw to Mn (Mw / Mn) by GPC of the polymer is usually 1 and preferably 1.2. As an upper limit of the ratio, 5 is preferable, 3 is more preferable, and 2 is more preferable.

<[E] solvent>
The radiation-sensitive resin composition usually contains an [E] solvent. [E] The solvent dissolves at least the [A] polymer and the [B] acid generator and the [C] acid generator, [D] polymer, [F] nitrogen-containing compound, etc. contained as necessary. There is no particular limitation as long as it is a dispersible solvent.

  [E] 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 aliphatic monoalcohol solvents having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcohol solvent having 3 to 18 carbon atoms such as cyclohexanol;
A C2-C18 polyhydric alcohol solvent such as propylene glycol;
Examples thereof include C3-C19 polyhydric alcohol partial ether solvents such as propylene glycol monomethyl ether.

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

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
2,4-pentanedione, acetonylacetone, acetophenone and the like can be mentioned.

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 monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvents such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate;
Polycarboxylic acid diester solvents such as diethyl oxalate;
lactone solvents such as γ-butyrolactone and δ-valerolactone;
Examples thereof include carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate.

Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents having 5 to 12 carbon atoms such as n-pentane and n-hexane;
Examples thereof include aromatic hydrocarbon solvents having 6 to 16 carbon atoms such as toluene and xylene.

  [E] As the solvent, ester solvents and ketone solvents are preferable, polyhydric alcohol partial ether carboxylate solvents and cyclic ketone solvents are more preferable, polyhydric alcohol partial alkyl ether acetates and cycloalkanones are more preferable, Propylene glycol monomethyl ether acetate and cyclohexanone are particularly preferred. The radiation-sensitive resin composition may contain one or more [E] solvents.

<[F] Nitrogen-containing compound>
The said radiation sensitive resin composition may contain a [F] nitrogen-containing compound in the range which does not impair the effect of this invention. [F] The nitrogen-containing compound serves as an acid diffusion control agent that controls the diffusion phenomenon in the resist film of the acid generated from [D] other acid generators and the like by exposure, and suppresses an undesirable chemical reaction in the non-exposed region. There is an effect. Further, the storage stability of the radiation sensitive resin composition is improved, and the resolution as a resist is further improved. Furthermore, a change in the line width of the resist pattern due to fluctuations in the holding time from exposure to development processing can be suppressed, and a radiation-sensitive resin composition excellent in process stability can be obtained.

  [F] Examples of the nitrogen-containing compound include a compound represented by the following formula (5) (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)”). Also referred to as “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. Is mentioned.

In the above formula (5), R ²⁰ , R ²¹ and R ²² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group or an 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; aniline and 2,6-dii-propyl And aromatic amines such as aniline.

  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; 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- (undecylcarbonyloxyethyl) morpholine; pyrazine, pyrazole, benzimidazole, and 2-phenyl. Examples include imidazoles such as benzimidazole.

  As the nitrogen-containing organic compound, a compound having an acid dissociable group can also be used. 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.

  When the said radiation sensitive resin composition contains a [F] nitrogen-containing compound as a [F] nitrogen-containing compound, as a minimum of content of a [F] nitrogen-containing compound, with respect to 100 mass parts of [A] polymers. 0.1 parts by mass is preferable, 0.3 parts by mass is more preferable, and 1 part by mass is more preferable. As an upper limit of the said content, 15 mass parts is preferable, 10 mass parts is more preferable, and 5 mass parts is further more preferable.

<Other optional components>
The said radiation sensitive resin composition may contain other arbitrary components other than the said [A]-[F] component. Examples of other optional components include surfactants, alicyclic skeleton-containing compounds, sensitizers, uneven distribution accelerators, and the like. Each of these other optional components may be used alone or in combination of two or more.

[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 dilaurate. Nonionic surfactants such as stearate;
Commercially available products include “KP341” from Shin-Etsu Chemical Co., Ltd., “Polyflow No. 75” and “No. 95” from Kyoeisha Chemical Co., Ltd. EF352, DIC's "Megafuck F171", "F173, Sumitomo 3M's" Florard FC430 "," FC431 ", Asahi Glass Industry's" Asahi Guard AG710 "," Surflon S-382 "," SC " -101 "," SC-102 "," SC-103 "," SC-104 "," SC-105 "," SC-106 ", and the like. The upper limit of the content of the surfactant is preferably 2 parts by mass and more preferably 1 part by mass with respect to 100 parts by mass of the [A] polymer.

[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.

[Sensitizer]
A sensitizer exhibits the effect | action which increases the production amount of the acid from a [B] acid generator, 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 an upper limit of content of a sensitizer, 2 mass parts is preferable with respect to 100 mass parts of [A] polymer, and 1 mass part is more preferable.

[Uneven distribution promoter]
The uneven distribution promoter is a component that makes the [D] polymer more unevenly distributed on the resist film surface when the radiation-sensitive resin composition contains the [D] polymer. When the radiation-sensitive resin composition contains an uneven distribution accelerator, the [D] polymer can be unevenly distributed more effectively on the resist film surface, and as a result, the amount of the [D] polymer used is reduced. can do. Examples of the uneven distribution promoter include lactone compounds, carbonate compounds, nitrile compounds, polyhydric alcohols, and the like. You may use an uneven distribution promoter individually by 1 type or in combination of 2 or more types.

  Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalolactone, norbornane lactone, and the like.

  Examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, and the like.

  Examples of the nitrile compound include succinonitrile.

  Examples of the polyhydric alcohol include glycerin.

  Of these, lactone compounds are preferred, and γ-butyrolactone is more preferred.

  When the radiation sensitive resin composition contains an uneven distribution accelerator, the lower limit of the content of the uneven distribution accelerator is preferably 5 parts by weight with respect to 100 parts by weight of the polymer [A]. More preferred is 20 parts by mass. The upper limit of the content is preferably 300 parts by mass, more preferably 100 parts by mass, and still more preferably 70 parts by mass with respect to 100 parts by mass of the [A] polymer.

<Method for preparing radiation-sensitive resin composition>
The radiation-sensitive resin composition includes, for example, a [A] polymer and a [B] acid generator, and a [C] radiation-sensitive acid generator, a [D] polymer, and an [E] solvent that are contained as necessary. , [F] a nitrogen-containing compound and other optional components are mixed at a predetermined ratio, and preferably, the obtained mixed solution can be prepared by filtering with a filter having a pore size of about 0.2 μm, for example. As a minimum of solid content concentration of the radiation sensitive resin composition, 0.1 mass% is preferred, 0.5 mass part is more preferred, and 1 mass% is still more preferred. As an upper limit of the said solid content concentration, 50 mass% is preferable, 30 mass% is more preferable, and 20 mass% is further more preferable.

  The radiation-sensitive resin composition can be used for forming a positive pattern using an alkaline developer and for forming a negative pattern using a developer containing an organic solvent. Among these, when used for forming a negative pattern using a developer containing an organic solvent, the radiation-sensitive resin composition can exhibit higher resolution.

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

  According to the resist pattern forming method, since the radiation-sensitive resin composition described above is used, LWR performance, resolution, rectangular shape of a cross-sectional shape, depth of focus, MEEF performance, development defect suppression, and after PEB It is possible to form a resist pattern excellent in the film shrinkage inhibiting property.

[Coating process]
In this step, the radiation sensitive resin composition is applied to one side of the substrate. Examples of the substrate on which the resist film is formed include a silicon wafer and a wafer coated with aluminum. A resist film is formed by applying the radiation sensitive resin composition on the substrate. Although it does not specifically limit as a coating method of the said radiation sensitive resin composition, For example, well-known methods, such as a spin coat method, etc. are mentioned. When the radiation sensitive resin composition is applied, the amount of the radiation sensitive resin composition to be applied is adjusted so that the resist film to be formed has a desired thickness. In addition, after coating the said radiation sensitive resin composition on a board | substrate, in order to volatilize a solvent, you may pre-bake (henceforth "PB"). As a minimum of the temperature of PB, 30 degreeC is preferable and 50 degreeC is more preferable. As an upper limit of the said temperature, 200 degreeC is preferable and 150 degreeC is more preferable. The lower limit of the PB time is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. As a minimum of the average thickness of a resist film, 10 nm is preferred, 20 nm is more preferred, and 50 nm is still more preferred. The upper limit of the average thickness is preferably 1,000 nm, more preferably 200 nm, and even more preferably 150 nm.

[Exposure process]
In this step, the resist film obtained by the coating step is exposed. In some cases, this exposure is performed by irradiating with radiation through a mask having a predetermined pattern through an immersion exposure liquid such as water.

  As the immersion exposure liquid, a liquid having a refractive index larger than that of air is usually used. Specific examples include pure water, long-chain or cyclic aliphatic compounds, and the like. In this state through the immersion exposure liquid, that is, in a state where the immersion exposure liquid is filled between the lens and the resist film, the exposure apparatus irradiates radiation, and the resist film is formed through a mask having a predetermined pattern. Exposure.

  Examples of the radiation include far ultraviolet rays such as visible light, ultraviolet rays, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), and extreme ultraviolet rays (depending on the type of radiation-sensitive acid generator used). Extreme Ultraviolet (EUV), 13.5 nm), electromagnetic waves such as X-rays, charged particle beams such as electron beams and α-rays, etc., are appropriately selected and used. Among these, ArF excimer laser light, KrF excimer laser Light, EUV, X-ray and electron beam are preferable, and ArF excimer laser light, EUV and electron beam are more preferable. In addition, exposure conditions, such as exposure amount, can be suitably selected according to the compounding composition of the said radiation sensitive resin composition, the kind of additive, etc.

  It is preferable to perform heat treatment (hereinafter also referred to as “post-exposure baking (post-exposure baking, PEB)”) on the resist film after exposure. By this PEB, the dissociation reaction of an acid dissociable group such as the [A] polymer can be smoothly advanced. The heating conditions for PEB are appropriately adjusted depending on the composition of the radiation sensitive resin composition, but the lower limit of the temperature of PEB is preferably 30 ° C, more preferably 50 ° C, and even more preferably 70 ° C. As an upper limit of the said temperature, 200 degreeC is preferable, 150 degreeC is more preferable, and 120 degreeC is further more preferable. The lower limit of the PEB time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. In the resist pattern forming method, since the radiation-sensitive resin composition is used, the film shrinkage suppression property after PEB is excellent.

  In order to maximize the potential of the radiation-sensitive resin composition, for example, as disclosed in Japanese Patent Publication No. 6-12452, Japanese Patent Application Laid-Open No. 59-93448, etc., on the substrate to be used. An organic or inorganic antireflection film can also be formed. In order to prevent the influence of basic impurities contained in the ambient atmosphere, a protective film can be provided on the resist film as disclosed in, for example, Japanese Patent Laid-Open No. 5-188598.

[Development process]
In this step, the resist film exposed in the exposure step is developed. Examples of the developer used for the development include an aqueous alkali solution (alkaline developer) and a solution containing an organic solvent (organic solvent developer). Thereby, a predetermined resist pattern is formed.

  Examples of the alkali developer 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. 0.0] -5-nonene, and an alkaline aqueous solution in which at least one of alkaline compounds is dissolved. In these, a TMAH aqueous solution is preferable and a 2.38 mass% TMAH aqueous solution is more preferable.

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

  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.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. The measuring method of various physical property values is shown below.

[Measurement of weight average molecular weight (Mw), number average molecular weight (Mn) and dispersity (Mw / Mn)]
Mw and Mn of the polymer are obtained by gel permeation chromatography (GPC) using Tosoh GPC columns ("G2000HXL", "G3000HXL", "G4000HXL") under the following conditions. It was measured. The degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

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

[ ¹ H-NMR analysis and ¹³ C-NMR analysis]
The analysis which calculated | required the content rate (mol%) of each structural unit in each polymer was performed using "JNM-Delta400" of JEOL.

<Synthesis of [A] polymer and [D] polymer>
The monomers used in the synthesis of each polymer in each example and comparative example are shown below.

  M-2, M-4, M-6, M-7, M-8, M-11, M-12, M-13 and M-14 are compounds having a large protective group having a sterically bulky structure. M-1 and M-3 were used as compounds having a small protective group having a small structure, and M-5, M-9 and M-10 were used as compounds having a polar group. In the following synthesis examples, unless otherwise specified, parts by mass means a value when the total mass of the monomers used is 100 parts by mass, and mol% indicates the total number of moles of the monomers used. It means the value when it is 100 mol%.

[Synthesis Example 1] (Synthesis of polymer (A-1))
Compound (M-1), compound (M-2), and compound (M-5) as monomers were dissolved in 2-butanone (200 parts by mass) so that the molar ratio was 25/25/50. Here, AIBN (5 mol%) was added as an initiator to prepare a monomer solution. 2-butanone (100 parts by mass) was placed in the reaction vessel and purged with nitrogen for 30 minutes. The monomer solution was added dropwise over 3 hours while stirring in a reaction vessel at 80 ° C. 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, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization solution was put into methanol (2000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-1) in good yield. Mw of the polymer (A-1) was 6,300, and Mw / Mn was 1.39. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M-1), (M-2), and (M-5) was 25.0 mol%, 24.3 mol%, and It was 50.7 mol%.

[Synthesis Examples 2 to 7 and Synthesis Examples 9 to 11] (Synthesis of Polymer (A-2) to Polymer (A-7) and Polymer (A-9) to Polymer (A-11))
A monomer is appropriately selected, and the same operation as in Synthesis Example 1 is performed to obtain a polymer (A-2) to a polymer (A-7) and a polymer (A-9) to a polymer (A-11). Synthesized.

[Synthesis Example 8] (Synthesis of polymer (A-8))
The compound (M-2) and the compound (M-10) as monomers were dissolved in propylene glycol monomethyl ether (100 parts by mass) so that the molar ratio was 50/50. A monomer solution was prepared by adding AIBN (6 mol%) as an initiator and t-dodecyl mercaptan (38 parts by mass relative to 100 parts by mass of the initiator) as a chain transfer agent. This monomer solution was copolymerized under a nitrogen atmosphere while maintaining the reaction temperature at 70 ° C. for 16 hours. After the completion of the polymerization reaction, the polymerization solution was dropped into n-hexane (1000 parts by mass) to solidify and purify the polymer. To the polymer, propylene glycol monomethyl ether (150 parts by mass) was added again. Further, methanol (150 parts by mass), triethylamine (1.5 molar equivalents relative to the amount of compound (M-10) used) and water (1.5 molar equivalents relative to the amount of compound (M-10) used) were added. Then, the hydrolysis reaction was carried out 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 acetone (150 parts by mass). This was dropped into water (2000 parts by mass) to solidify, and the produced white powder was filtered off. It was dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-8) in a good yield. Mw of the polymer (A-8) was 6,300, and Mw / Mn was 1.90. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M-2) and (M-10) was 49.3 mol% and 50.7 mol%, respectively.

[Synthesis Example 12] (Synthesis of Polymer (A-12))
A monomer was selected and the same operation as in Synthesis Example 8 was performed to synthesize a polymer (A-12).

[Synthesis Example 13] (Synthesis of Polymer (D-1))
The compound (M-1) and the compound (M-9) as monomers were dissolved in 2-butanone (200 parts by mass) so that the molar ratio was 70/30. AIBN (5 mol% with respect to all monomers) was added here as an initiator to prepare a monomer solution. 2-butanone (100 parts by mass) was placed in the reaction vessel and purged with nitrogen for 30 minutes. The inside of the reaction vessel was set to 80 ° C., and the monomer solution was added dropwise over 3 hours with stirring. 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, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. After replacing the solvent with acetonitrile (400 parts by mass), the operation of adding hexane (100 parts by mass) and stirring to recover the acetonitrile layer was repeated three times. By replacing the solvent with propylene glycol monomethyl ether acetate, a solution of the polymer (D-1) was obtained in good yield. Mw of the polymer (D-1) was 7,300, and Mw / Mn was 2.00. As a result of ¹³ C-NMR analysis, the content ratios of structural units derived from (M-1) and (M-9) were 71.1 mol% and 28.9 mol%, respectively.

  The content ratio, yield, Mw, and Mw / Mn of each structural unit of the obtained polymer are shown in Table 1. In the following table, “-” indicates that the corresponding component was not used.

＊Ｍ−１０に由来するｐ−ヒドロキシスチレン構造単位を示す

* Indicates p-hydroxystyrene structural unit derived from M-10

<Preparation of radiation-sensitive resin composition>
It shows about components other than the [A] polymer and the [D] polymer which comprise a radiation sensitive resin composition.

[[B] acid generator]
[B] Compounds represented by the following formulas (B-1) to (B-7) were used as acid generators.

[[C] acid generator (acid diffusion controller)]
[C] Compounds represented by the following formulas (C-1) to (C-2) were used as acid generators.
C-1: Triphenylsulfonium 10-camphorsulfonate C-2: Triphenylsulfonium salicylate

[[E] solvent]
[E] The following (E-1) to (E-4) were used as solvents.
E-1: Propylene glycol monomethyl ether acetate E-2: Cyclohexanone E-3: γ-Butyrolactone E-4: Ethyl lactate

[[F] Nitrogen-containing compound]
[F] A compound represented by the following formula (F-1) was used as the nitrogen-containing compound.
F-1: N- (n-undecan-1-ylcarbonyloxyethyl) morpholine

[Example 1]
[A] 100 parts by mass of (A-1) as a polymer, [B] 10 parts by mass of (B-2) as an acid generator, [C] 7 parts by mass of (C-1) as an acid diffusion controller [D] 3 parts by mass as a polymer, (E-1) 2,240 parts by mass, (E-2) 960 parts by mass and (E-3) 30 parts by mass as a solvent. The radiation sensitive resin composition (J-1) was prepared by mixing parts and filtering with a membrane filter having a pore size of 0.2 μm.

[Examples 2 to 14 and Comparative Examples 1 to 4]
The radiation sensitive resin compositions (J-2) to (J-14) and (K-1) to (K-1) to (K) were used in the same manner as in Example 1 except that the components having the types and contents shown in Table 2 below were used. K-4) was prepared.

<Formation of resist pattern (1): ArF excimer laser immersion exposure, organic solvent development>
On the surface of a 12-inch silicon wafer, using a spin coater (“CLEAN TRACK ACT12” manufactured by Tokyo Electron), a composition for forming a lower antireflection film (“ARC66” manufactured by Brewer Science) was applied at 205 ° C. Was heated for 60 seconds to form a lower antireflection film having a thickness of 105 nm. On the lower antireflection film, each radiation sensitive resin composition was applied using the spin coater, and PAB (Post applied baking) was performed at 100 ° C. for 50 seconds. Thereafter, it was cooled at 23 ° C. for 30 seconds to form a resist film having a thickness of 90 nm. Next, using ArF excimer laser immersion exposure apparatus (“TWINSCAN XT-1900i” manufactured by ASML), this coating film was subjected to optical conditions of NA = 1.35 and Annular (σ = 0.8 / 0.6). Then, exposure was performed through a mask pattern for forming a resist pattern having a 58 nm hole and a 96 nm pitch. After the exposure, PEB was performed at 90 ° C. for 50 seconds. Thereafter, paddle development was performed for 10 seconds at 23 ° C. using n-butyl acetate, and spin drying was performed by shaking off at 2,000 rpm for 15 seconds to form a resist pattern having 48 nm holes and 96 nm pitches. When this resist pattern was formed, the exposure amount at which the hole pattern size was 48 nm was determined as the optimum exposure amount (Eop).

<Formation of resist pattern (2): ArF excimer laser immersion exposure, alkali development>
On the surface of a 12-inch silicon wafer, using a spin coater (“CLEAN TRACK ACT12” manufactured by Tokyo Electron), a composition for forming a lower antireflection film (“ARC66” manufactured by Brewer Science) was applied at 205 ° C. Was heated for 60 seconds to form a lower antireflection film having a thickness of 105 nm. Each radiation sensitive resin composition was applied onto the lower antireflection film using the spin coater, and PAB was performed at 100 ° C. for 50 seconds. Thereafter, it was cooled at 23 ° C. for 30 seconds to form a resist film having a thickness of 90 nm. Next, this coating film was subjected to an optical condition of NA = 1.35, Dipole 35X (σ = 0.97 / 0.77) using an ArF excimer laser immersion exposure apparatus (“TWINSCAN XT-1900i” manufactured by ASML). Then, it was exposed through a mask pattern for forming a resist pattern of 38 nm line and space (1L / 1S). After the exposure, PEB was performed at 90 ° C. for 50 seconds. Then, perform paddle development for 30 seconds at 23 ° C. using an aqueous 2.38 mass% TMAH solution, then rinse for 7 seconds using ultrapure water, and then spin dry at 2,000 rpm for 15 seconds. As a result, a 40 nm line and space (1L / 1S) resist pattern was formed. When this resist pattern was formed, the exposure amount for forming a line with a line width of 40 nm formed through a mask pattern for pattern formation with a target dimension of 40 nm line and space was defined as the optimum exposure amount (Eop).

<Evaluation>
About the formed resist pattern, each radiation sensitive resin composition was evaluated by measuring according to the following method. The evaluation results are shown in Table 3 below. A scanning electron microscope (Hitachi High-Technologies “CG-5000”) was used for measuring the resist pattern.

[CDU performance]
The hole pattern formed by irradiating with the same exposure as Eop obtained in the formation of the resist pattern (1) was observed from above the pattern using the scanning electron microscope. The hole diameter is measured at 16 points in a 400nm square area, and the average value is obtained. The average value is measured at a total of 500 points, and the 3 sigma value is obtained from the distribution of the measured values. (Nm). The smaller the value of the CDU performance, the better the variation in hole diameter over a long period. The CDU performance can be evaluated as “good” when it is 5.0 nm or less, and “bad” when it exceeds 5.0 nm.

[MEEF]
The hole pattern formed by irradiating with the same exposure as Eop obtained in the formation of the resist pattern (1) was observed from above the pattern using the scanning electron microscope. The hole diameter was measured at 16 points in a 400 nm square side to determine the average value, and the average value was measured at 100 arbitrary points to calculate the average hole diameter. The same measurement was performed under five conditions with different mask sizes in increments of 1 nm, and the hole diameter change amount relative to the mask change amount was defined as MEEF performance (nm). The smaller the value of MEEF performance, the better the mask fidelity. The MEEF performance can be evaluated as “good” when it is 3.9 nm or less, and “bad” when it exceeds 3.9 nm.

[LWR performance]
The line and space pattern formed by irradiating with the same exposure amount as Eop obtained in the formation of the resist pattern (2) was observed from above the pattern using the scanning electron microscope. A total of 500 line width variations were measured, and a 3-sigma value was determined from the distribution of the measured values, and this was defined as LWR performance (nm). The smaller the value of the LWR performance, the smaller the line play and the better. The LWR performance can be evaluated as “good” when it is 3.9 nm or less and “bad” when it exceeds 3.9 nm.

[Example 15]
[A] 100 parts by mass as a polymer (A-8), [B] 20 parts by mass as an acid generator (B-2), [C] 2.5 parts by mass as an acid generator (C-3) Part, (E-1) 4280 parts by mass as solvent and (E-4) 1830 parts by mass are mixed and filtered through a 0.2 μm membrane filter to produce a radiation sensitive resin composition (J- 15) was prepared.

[Examples 16 to 17 and Comparative Examples 5 to 6]
The radiation sensitive resin compositions (J-16) to (J-17) and (K-5) to (K) are used in the same manner as in Example 15 except that the components having the types and contents shown in Table 4 below are used. K-6) was prepared.

<Formation of resist pattern (3): electron beam exposure, alkali development>
Using a spin coater (CLEAN TRACK ACT8, manufactured by Tokyo Electron) on the surface of an 8-inch silicon wafer, each radiation sensitive resin composition described in Table 4 was applied, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 50 nm. Next, the resist film was irradiated with an electron beam using a simple electron beam drawing apparatus (manufactured by Hitachi, model “HL800D”, output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 120 ° 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 having 100 nm holes and 200 nm pitches.

<Evaluation>
About the radiation sensitive resin composition, according to the said method, CDU performance of the resist pattern formed by irradiating the optimal exposure amount (Eop) was evaluated. For measuring the resist pattern, a scanning electron microscope (S-9380, manufactured by Hitachi High-Technologies Corporation) was used. The results are shown in Table 5 below.

In the results of Table 3 above, it was shown that the radiation-sensitive resin composition was good in all cases of CDU performance and MEEF performance in organic solvent development and LWR performance in alkali development in ArF exposure. In particular, the examples containing the polymers having i-propyl groups in the end-type dinorbornane structures of Examples 1, 2 and 9 to 11 gave excellent results.
Moreover, in the result of Table 5, the CDU performance was also favorable when the radiation sensitive resin composition was subjected to alkali development in electron beam exposure. On the other hand, it was shown that the radiation sensitive resin composition of the comparative example is inferior in CDU performance to that of the example. In general, it is known that electron beam exposure shows the same tendency as in EUV exposure. Therefore, from the results of this example, it is presumed that excellent CDU performance and limit resolution are exhibited even in the case of EUV exposure.

  According to the radiation sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern having excellent LWR performance, CDU performance, and MEEF performance can be formed. The compound of the present invention can be suitably used as a raw material monomer for the polymer. Therefore, they can be suitably used for pattern formation in semiconductor device manufacturing or the like where further miniaturization is expected.

Claims (6)

A first polymer having a first structural unit represented by the following formula (1);
A first radiation-sensitive acid generator that generates sulfonic acid or disulfonylimide acid,
A radiation-sensitive resin composition in which the first radiation-sensitive acid generator includes a group having a polycyclic structure and an anion having one or more fluorine atoms.

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms. N is 0. R ³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and when n is 2 or more, the plurality of R ³ are each independently a group having 1 to 20 carbon atoms. It is a monovalent hydrocarbon group, or a plurality of R ³ are combined together to form an alicyclic structure having 3 to 20 ring members together with the carbon atom or carbon chain to which these are bonded. The radiation-sensitive resin composition according to claim 1, wherein the hydrocarbon group of R ^{2 in} the above formula (1) has 3 to 20 carbon atoms. Further containing a second radiation sensitive acid generator other than the first radiation sensitive acid generator,
The radiation sensitive resin according to claim 1 or 2, wherein the acidity of the acid generated by the second radiation sensitive acid generator is lower than the acidity of the acid generated by the first radiation sensitive acid generator. Composition. The radiation-sensitive resin composition according to claim 1, wherein the first structural unit is represented by the following formula (1-1) or the following formula (1-2).

(In the above formulas (1-1) and (1-2), R ¹ , R ² , R ³ and n are as defined in the above formula (1).)   The radiation sensitive resin composition of any one of Claims 1-4 which further contains the 2nd polymer with a mass content rate of a fluorine atom larger than the said 1st polymer. A step of applying the radiation-sensitive resin composition according to any one of claims 1 to 5 on one surface side of the substrate;
Exposing the resist film obtained by the coating step;
And a step of developing the exposed resist film.