JP2016170230A - Radiation-sensitive resin composition and method for forming resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition capable of sufficiently reducing hydrophobicity of a resist film surface after developed and excellent in inhibiting property for development defects, and a method for forming a resist pattern by using the radiation-sensitive resin composition.SOLUTION: A radiation-sensitive resin composition comprises: a polymer having a structural unit having a specific structure and containing a fluorine atom; a polymer having a smaller content percentage of fluorine atoms than that of the above polymer, and showing changes in the solubility with a developer by an action of an acid; a radiation-sensitive acid generator; and a solvent.SELECTED DRAWING: None

Description

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

  A chemically amplified radiation-sensitive resin composition used for fine processing by lithography generates an acid in an exposed area by irradiation with ArF excimer laser light, etc., and an exposed area and an unexposed area by a chemical reaction using this acid as a catalyst. Thus, a resist pattern is formed by causing a difference in dissolution rate with respect to the developer.

  In the formation of such a resist pattern, an immersion exposure method is suitably used as a method for forming a finer resist pattern. In this method, the exposure lens and the resist film are filled with an immersion exposure medium having a refractive index higher than that of air or an inert gas for exposure. According to this immersion exposure method, there is an advantage that high resolution can be obtained and the depth of focus is hardly lowered even when the numerical aperture of the lens is increased.

  The radiation-sensitive resin composition used in such an immersion exposure method suppresses the elution of a radiation-sensitive acid generator from the resist film to the immersion exposure medium, and has good drainage on the surface of the resist film. Is required. As such a radiation-sensitive resin composition, in addition to a base polymer having an acid-dissociable group, a composition containing a fluorine atom-containing polymer that is unevenly distributed in the surface layer when a resist film is formed has been proposed (international (See Publication No. 2007/116664). In addition, when the hydrophobicity of the resist film surface is increased, the surface wettability of the developer and the rinsing solution is reduced, so that the development residue deposited on the unexposed portion of the resist surface during development becomes insufficient, and the blob (Blob) Development defects such as the above may occur. For the purpose of suppressing such development defects, a fluorine-containing polymer that is hydrophobic during immersion exposure but decreases in hydrophobicity during alkali development, specifically, a fluoroalkyl group was introduced into the carboxy group. Fluorine-containing polymers (see JP 2010-032994) and fluorine-containing polymers in which a highly hydrophobic fluoroacyl group is introduced into a phenolic hydroxyl group (see JP 2009-139909 A) are being studied.

  However, when the conventional radiation-sensitive resin composition is used, the degree of decrease in the hydrophobicity of the resist film surface during development is still insufficient, and therefore the occurrence of development defects can be sufficiently suppressed. There is inconvenience that there is not.

International Publication No. 2007/116664 JP 2010-032994 A JP 2009-139909 A

  The present invention has been made on the basis of the circumstances as described above, and the object thereof is to sufficiently reduce the hydrophobicity of the resist film surface after development, and as a result, a radiation-sensitive resin excellent in development defect suppression. It is in providing the composition and the resist pattern formation method using this radiation sensitive resin composition.

（式（１）中、Ｘ^１及びＸ^２は、それぞれ独立して、炭素数１〜３０の１価の有機基である。ｍは、１〜３の整数である。ｍが２以上の場合、複数のＸ^１は同一でも異なっていてもよい。但し、Ｘ^１及びＸ^２のうちの少なくともいずれかは下記式（Ａ）で表される基である。Ｙは、炭素数１〜５の（ｍ＋１）価の鎖状炭化水素基である。）

（式（Ａ）中、Ｚ^１及びＺ^２は、それぞれ独立して、水素原子又は炭素数１〜２０の１価の炭化水素基である。Ｌ^１は、単結合、炭素数１〜２０の２価の鎖状炭化水素基又は環員数３〜２０の２価の脂環式炭化水素基である。Ｚ^１、Ｚ^２及びＬ^１のうちの２以上は、互いに合わせられ、これらが結合する炭素原子と共に構成される環員数３〜２０の脂環構造を形成していてもよい。Ｒ^１及びＲ^２は、それぞれ独立して、水素原子、フッ素原子、炭素数１〜２０の１価の炭化水素基又は炭素数１〜２０の１価のフッ素化炭化水素基である。Ｒ^１とＲ^２とは、互いに合わせられ、これらが結合する炭素原子と共に構成される環員数３〜２０の環構造を形成していてもよい。Ｒ^３は、炭素数１〜２０の１価の炭化水素基又は炭素数１〜２０の１価のフッ素化炭化水素基である。但し、Ｒ^１、Ｒ^２及びＲ^３のうちの少なくともいずれかはフッ素原子を有する。） The invention made in order to solve the above-mentioned problems is a first polymer having a first structural unit represented by the following formula (1) (hereinafter also referred to as “structural unit (I)”) (hereinafter referred to as “[A ] Second polymer (hereinafter referred to as “[B]”), which has a smaller fluorine atom mass content than the above [A] polymer and changes its solubility in a developer due to the action of an acid. A radiation-sensitive resin composition containing a radiation-sensitive acid generator (hereinafter also referred to as “[C] acid generator”) and a solvent (hereinafter also referred to as “[D] solvent”). It is a thing.

(In Formula (1), X ¹ and X ² are each independently a monovalent organic group having 1 to 30 carbon atoms. M is an integer of 1 to 3. When m is 2 or more. A plurality of X ¹ may be the same or different, provided that at least one of X ¹ and X ² is a group represented by the following formula (A): Y is a group having 1 to 5 carbon atoms. (M + 1) a valent chain hydrocarbon group.)

(In formula (A), Z ¹ and Z ² are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. L ¹ is a single bond, having 1 to 20 carbon atoms. A divalent chain hydrocarbon group or a divalent alicyclic hydrocarbon group having 3 to 20 ring members, two or more of Z ¹ , Z ² and L ¹ are combined with each other and bonded together. An alicyclic structure having 3 to 20 ring members and a carbon atom may be formed, and R ¹ and R ² are each independently a hydrogen atom, a fluorine atom, or a monovalent monovalent group having 1 to 20 carbon atoms. A hydrocarbon group or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, R ¹ and R ² are combined with each other, and a ring having 3 to 20 ring members configured together with the carbon atom to which they are bonded; optionally form a structure .R ³ is a monovalent hydrocarbon group or a C 1 -C 20 from 1 to 20 carbon atoms A monovalent fluorinated hydrocarbon group. Provided that at least one of R ^1, R ² and R ³ are a fluorine atom.)

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

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

  According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, the hydrophobicity of the resist film surface after development can be sufficiently reduced, and a resist pattern with few development defects can be formed. Therefore, these can be suitably used in the manufacturing process of semiconductor devices and the like that are expected to be further miniaturized in the future.

<Radiation sensitive resin composition>
The radiation-sensitive resin composition contains a [A] polymer, a [B] polymer, a [C] acid generator, and a [D] solvent. The radiation-sensitive resin composition may contain [E] acid diffusion controller and [F] uneven distribution accelerator as suitable components, and contains other optional components as long as the effects of the present invention are not impaired. May be. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I). [A] The mass content of fluorine atoms in the polymer is greater than the mass content of fluorine atoms in the polymer [B] described later. Therefore, the [A] polymer functions as a water-repellent polymer additive that is unevenly distributed in the surface layer than the [B] polymer during the formation of the resist film, and as a result, the resist film during exposure, particularly during immersion exposure. The water repellency of the surface can be increased. Here, the mass content (% by mass) of fluorine atoms in each polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR analysis or the like.

  [A] The lower limit of the mass content of fluorine atoms in the polymer is preferably 3% by mass, more preferably 10% by mass, and even more preferably 15% 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.

  [A] In addition to the structural unit (I), the polymer includes a structural unit (II) containing a fluorine atom other than the structural unit (I), and a structural unit (III) containing an acid-dissociable group other than the structural unit (I). ), A lactone structure, a cyclic carbonate structure, a structural unit (IV) containing a sultone structure or a combination thereof, a structural unit (V) containing an alcoholic hydroxyl group, and a structural unit (VI) containing a phenolic hydroxyl group. Good. [A] The polymer may have one or more of each structural unit. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit represented by the following formula (1).

The formula (1), ^{X 1} and ^{X 2} are each independently a monovalent organic group having 1 to 30 carbon atoms. m is an integer of 1-3. When m is 2 or more, the plurality of X ¹ may be the same or different. However, at least one of X ¹ and X ² is a group represented by the following formula (A). Y is a (m + 1) -valent chain hydrocarbon group having 1 to 5 carbon atoms.

In the above formula (A), Z ¹ and Z ² are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. L ¹ is a single bond, a divalent chain hydrocarbon group having 1 to 20 carbon atoms, or a divalent alicyclic hydrocarbon group having 3 to 20 ring members. Two or more of Z ¹ , Z ^2, and L ¹ may be combined with each other to form an alicyclic structure having 3 to 20 ring members that is configured together with the carbon atom to which they are bonded. R ¹ and R ² 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 ¹ and R ² may be combined with each other to form a ring structure having 3 to 20 ring members constituted together with the carbon atom to which they are bonded. R ³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. However, at least one of R ¹ , R ² and R ³ has a fluorine atom.

In the radiation-sensitive resin composition, the [A] polymer has the structural unit (I), so that the hydrophobicity of the resist film surface after development can be sufficiently lowered, and as a result, a resist pattern with few development defects. Can be formed. The reason why the radiation-sensitive resin composition exhibits the above-described effect by having the above-described configuration is not necessarily clear, but can be inferred as follows, for example. That is, the structural unit (I) of the [A] polymer has a group represented by the above formula (A) (hereinafter also referred to as “group (A)”). In this group (A), since at least one of R ^{1 to} R ^{3 in} the vicinity of —COO— has a fluorine atom, R ³ becomes an alkali dissociable group. In addition, the alkali-dissociable group R ³ is bonded via the —C (Z ¹ ) (Z ² ) -L ¹ -C (R ¹ ) (R ² ) —COO— in the above formula (A). A] The alkali dissociation property is higher because it is appropriately separated from the main chain of the polymer. As a result, the resist film formed from the radiation-sensitive resin composition has a surface hydrophobicity that is greatly reduced during development, so that development and subsequent rinsing can be performed sufficiently easily. Therefore, it is considered that the radiation-sensitive resin composition can suppress development defects when forming a resist pattern. Here, the “alkali dissociable group” is a group that replaces a hydrogen atom of a carboxy group, and is a group that dissociates with an aqueous 2.38 mass% tetramethyl hydroxide solution at 23 ° C., for example.

Examples of the monovalent organic group having 1 to 30 carbon atoms represented by X ¹ and X ² in the above formula (1) include, for example, a monovalent hydrocarbon group having 1 to 30 carbon atoms, and carbon- A group (α) containing a divalent heteroatom-containing group at the terminal between carbons or at the bond side, a part or all of the hydrogen atoms of the hydrocarbon group and group (α) is a monovalent heteroatom-containing group Examples include substituted groups.

  Examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms include a chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and an aromatic carbon group having 6 to 30 carbon atoms. A hydrogen group etc. are mentioned.

Examples of the monovalent chain hydrocarbon group having 1 to 30 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t -An alkyl group such as a butyl group;
An alkenyl group such as an ethenyl group, a propenyl group, a butenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group and butynyl group.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms include monocyclic cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group;
A monocyclic cycloalkenyl group such as a cyclobutenyl group, a cyclopentenyl group, or a cyclohexenyl group;
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
And polycyclic cycloalkenyl groups such as a norbornenyl group, a tricyclodecenyl group, and a tetracyclododecenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group;
Examples include aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group, naphthylmethyl group, and the like.

  Examples of the hetero atom contained in the divalent hetero atom-containing group include an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom, and a phosphorus atom. In these, an oxygen atom, a sulfur atom, and a nitrogen atom are preferable, and an oxygen atom is more preferable.

  Examples of the divalent heteroatom-containing group include —O—, —CO—, —CS—, —NR′—, and a combination thereof. R ′ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

  Examples of the monovalent heteroatom-containing group include a hydroxy group, a carboxy group, a sulfanyl group (—SH), an amino group, a cyano group, and a halogen atom.

X ¹ and X ² include a hydrocarbon group, a fluorinated hydrocarbon group, a group containing a lactone structure, and a group containing —O— from the viewpoint of further improving the development defect suppression of the radiation-sensitive resin composition. Preferably, an alkyl group, a fluorinated alkyl group, a cycloalkyl group, an aryl group, a group containing a polycyclic lactone structure and a cycloalkyloxyalkyl group are more preferable, an alkyl group having 1 to 5 carbon atoms and an alkyl group having 1 to 5 carbon atoms. A fluorinated alkyl group is particularly preferred, and a methyl group and a trifluoroethyl group are particularly preferred.

(Group (A))
At least one of X ¹ and X ² in the above formula (1) is a group (A).

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by Z ¹ and Z ² include carbon among the groups exemplified as the monovalent hydrocarbon group having 1 to 30 carbon atoms of X ¹ and X ^2. The thing of number 1-20 etc. are mentioned.

Z ¹ and Z ² are preferably a hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrocarbon group having 1 to 5 carbon atoms, and still more preferably a chain hydrocarbon group having 1 to 5 carbon atoms. And an alkyl group having 1 to 5 carbon atoms is particularly preferable, and a methyl group, an ethyl group, and an isopropyl group are particularly preferable.

Examples of the divalent chain hydrocarbon group having 1 to 20 carbon atoms represented by L ¹ include alkanediyl groups such as methanediyl group, ethanediyl group, propanediyl group, butanediyl group, and pentanediyl group;
Alkenediyl groups such as ethenediyl group, propenediyl group, butenediyl group, pentenediyl group;
Examples include alkynediyl groups such as ethynediyl group, propynediyl group, butynediyl group, and pentynediyl group. Among these, an alkanediyl group is preferable, and an ethanediyl group, a propanediyl group, and a pentanediyl group are more preferable.

Examples of the divalent alicyclic hydrocarbon group having 3 to 20 ring members represented by L ¹ include monocyclic cycloalkanediyl such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, and cyclohexanediyl group. Group;
Polycyclic cycloalkanediyl groups such as norbornanediyl group, adamantanediyl group, tricyclodesandiyl group, tetracyclododesandiyl group;
Monocyclic cycloalkenediyl groups such as cyclopropenediyl group, cyclobutenediyl group, cyclopentenediyl group, cyclohexenediyl group;
Examples thereof include polycyclic cycloalkenediyl groups such as norbornenediyl group and tricyclodecenediyl group.

L ¹ is preferably a single bond and a chain hydrocarbon group having 1 to 20 carbon atoms, more preferably a single bond and a chain hydrocarbon group having 1 to 6 carbon atoms, and an alkanediyl group having 1 to 6 carbon atoms. Further preferred are a propanediyl group and a butanediyl group. By making L ¹ as described above, the alkali dissociable group R ³ can be more appropriately separated from the main chain of the [A] polymer, so that the alkali dissociation property of R ³ is further improved. As a result, the development defect suppression property of the radiation-sensitive resin composition can be further improved.

Two or more of Z ¹ , Z ^2, and L ¹ are combined with each other, and examples of the alicyclic structure having 3 to 20 ring members configured together with the carbon atom to which they are bonded include a cyclopropane structure, a cyclobutane structure, Monocyclic cycloalkane structures such as structures, cyclohexane structures, cycloheptane structures, cyclooctane structures;
Examples thereof include polycyclic cycloalkane structures such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure.

Z ¹ and L ¹ are preferably combined with each other and form an alicyclic structure having 3 to 20 ring members constituted with the carbon atom to which they are bonded, and more preferably form a cycloalkane structure. Preferably, it forms a monocyclic cycloalkane structure, more preferably forms a cyclohexane structure. Since Z ¹ and L ¹ form the alicyclic structure, the solubility of the [A] polymer in the exposed portion of the resist film can be further increased. As a result, the radiation sensitive resin composition Development defect suppression can be further improved.

Examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms represented by R ¹ , R ² and R ³ include the groups exemplified as the monovalent hydrocarbon group having 1 to 30 carbon atoms of X ¹ and X ^2. And the like groups.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 30 carbon atoms represented by R ¹ , R ² and R ³ include, for example, monovalent hydrocarbon groups having 1 to 30 carbon atoms of X ¹ and X ^2. And a group in which some or all of the hydrogen atoms in the group are substituted with fluorine atoms.

Examples of the alicyclic structure having 3 to 20 ring members formed by combining R ¹ and R ² together with the carbon atom to which they are bonded include, for example, two or more of Z ¹ , Z ² and L ¹ described above. Examples thereof include structures similar to those exemplified as the alicyclic structure having 3 to 20 ring members.

R ¹ and R ² are preferably a hydrogen atom and a fluorine atom, and more preferably a fluorine atom.

R ³ is preferably a hydrocarbon group having 1 to 30 carbon atoms and a fluorinated hydrocarbon group having 1 to 30 carbon atoms, more preferably a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms, and 1 carbon atom. To 5 monovalent fluorinated hydrocarbon groups are more preferred, fluorinated alkyl groups having 1 to 5 carbon atoms are particularly preferred, and trifluoroethyl groups and perfluoroethyl groups are most preferred.

  As m, 1 and 2 are preferable and 1 is more preferable.

Examples of the (m + 1) -valent chain hydrocarbon group having 1 to 5 carbon atoms represented by Y include, for example, a methanediyl group and an ethanediyl group as a divalent (m = 1) chain hydrocarbon group having 1 to 5 carbon atoms. , Propanediyl group, butanediyl group, pentanediyl group;
Ethenediyl group, propenediyl group, butenediyl group, pentenediyl group;
Ethynediyl group, propynediyl group, butynediyl group, pentynediyl group, etc.
A methanetriyl group, ethanetriyl group, propanetriyl group, butanetriyl group, pentanetriyl group as a trivalent (m = 2) chain hydrocarbon group having 1 to 5 carbon atoms;
Ethenetriyl group, propenetriyl group, butenetriyl group, pentenetriyl group;
Ethyne triyl group, propyne triyl group, butyne triyl group, pentyne triyl group, etc.
A methanetetrayl group, ethanetetrayl group, propanetetrayl group, butanetetrayl group, pentanetetrayl group as a tetravalent (m = 3) chain hydrocarbon group having 1 to 5 carbon atoms;
Ethenetetrayl group, propenetetrayl group, butenetetrayl group, pentenetetrayl group;
Examples include ethynetetrayl group, propynetetrayl group, butynetetrayl group, and pentynetetrayl group.

  Among these, a methanediyl group, an ethanediyl group, a propanediyl group and a butanediyl group are preferable, a methanediyl group and an ethanediyl group are more preferable, and a methanediyl group is more preferable. When m is 1 and Y is a methanediyl group, the monomer giving the structural unit (I) can be easily synthesized from itaconic acid or a derivative thereof.

The group (A) is preferably an acid dissociable group. In the radiation-sensitive resin composition, since the group (A) is an acid-dissociable group, the solubility of the [A] polymer in the exposed portion of the resist film can be further increased, and as a result, development defects can be suppressed. The sex can be further improved. Examples of the case where the group (A) is an acid dissociable group include a case where both Z ¹ and Z ² are hydrocarbon groups and the carbon atom to which Z ¹ and Z ² are bonded is tertiary. Here, the “acid-dissociable group” refers to a group that substitutes a hydrogen atom of a carboxy group and dissociates by the action of an acid.

X ¹ in the above formula (1) may be the group (A), X ² may be the group (A), and X ¹ and X ² may each be the group (A). X ² is preferably a group (A). When X ¹ and X ² are a group (A), the ^two groups (A) may be the same or different.

  As the structural unit (I), for example, structural units represented by the following formulas (1-1) to (1-19) (hereinafter also referred to as “structural units (I-1) to (I-19)”) and the like Is mentioned.

  Among these, from the viewpoint of further improving the development defect suppression of the radiation-sensitive resin composition, the structural units (I-1) to (I-15) are preferable, and the structural units (I-1) to (I-1) -4), (I-7), (I-8), and (I-11) to (1-15) are more preferable.

  As a minimum of the content rate of structural unit (I), 70 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 80 mol% is more preferable, 90 mol% is further more preferable, and 95 mol % Is particularly preferred. By making the content rate of structural unit (I) into the said range, the development defect inhibitory property of the said radiation sensitive resin composition can further be improved.

  [A] The polymer is most preferably a monomer homopolymer having a content of the structural unit (I) of 100 mol%, that is, substantially giving the structural unit (I). According to the structural unit (I), since the mass content of fluorine atoms can be increased, even if the polymer [A] is a homopolymer having high uniformity, the resist film surface has high hydrophobicity and development. In this case, it is easy to achieve both the degree of hydrophobicity reduction. As a result, the development defect suppression of the radiation sensitive resin composition can be further improved.

  The monomer that gives the structural unit (I) is, for example, itaconic acid derivatives such as itaconic acid, itaconic acid monoester, itaconic acid diester when m in the above formula (1) is 1 and Y is a methanediyl group. It can be synthesized by esterification reaction, transesterification reaction or the like. Other monomers that give structural unit (I) can also be synthesized by the same method as described above.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a fluorine atom and different from the structural unit (I). [A] When the polymer has the structural unit (II), the mass content of fluorine atoms can be adjusted to a more appropriate one, and as a result, the development defect suppression of the radiation-sensitive resin composition can be improved. It can be improved further.

  Examples of the structural unit (II) include a structural unit represented by the following formula (2-1) (hereinafter also referred to as “structural unit (II-1)”) and a structure represented by the following formula (2-2). Unit (hereinafter also referred to as “structural unit (II-2)”) and the like.

In the above formula (2-1), R ^A is a hydrogen atom, a methyl group or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, —CO—O—, —SO ₂ —O—NH—, —CO—NH— or —O—CO—NH—. R ⁴ is a monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms.

In the above formula (2-2), R ^B is a hydrogen atom, a methyl group or a trifluoromethyl group. R ^C is a (s + 1) -valent hydrocarbon group having 1 to 20 carbon atoms, terminal oxygen atom of ^{R D} side of ^{R C,} a sulfur atom, -NR '- (where, R' is or a hydrogen atom 1 And a structure having a carbonyl group, —CO—O— or —CO—NH— bonded thereto. ^RD is a single bond, a C1-C10 bivalent chain hydrocarbon group, or a C4-C20 bivalent alicyclic hydrocarbon group. X ³ is a divalent chain fluorinated hydrocarbon group having 1 to 20 carbon atoms. A is an oxygen atom, —NR ″ — (where R ″ is a hydrogen atom or a monovalent organic group), —CO—O— * or —SO ₂ —O— * (* represents R ⁵⁾ . The bond to be combined is shown.) R ⁵ is a hydrogen atom or a monovalent organic group. s is an integer of 1 to 3. However, when s is 2 or 3, the plurality of R ^D may be the same or different, the plurality of X ³ may be the same or different, the plurality of A may be the same or different, R ⁵ may be the same or different.

Examples of the fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by R ⁴ include trifluoromethyl group, 2,2,2-trifluoroethyl group, perfluoroethyl group, 2,2,3, 3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, perfluoro n-propyl group, perfluoro i-propyl group, perfluoro n-butyl group, perfluoro i -Butyl group, perfluoro t-butyl group, 2,2,3,3,4,4,5,5-octafluoropentyl group, perfluorohexyl group and the like.

Examples of the fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ⁴ include a monofluorocyclopentyl group, a difluorocyclopentyl group, a perfluorocyclopentyl group, a monofluorocyclohexyl group, a difluorocyclopentyl group, and a perfluorocyclohexyl group. Examples thereof include a methyl group, a fluoronorbornyl group, a fluoroadamantyl group, a fluorobornyl group, a fluoroisobornyl group, a fluorotricyclodecyl group, and a fluorotetracyclodecyl group.

  Examples of the monomer that gives the structural unit (II) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, Perfluoro n-propyl (meth) acrylic acid ester, perfluoro i-propyl (meth) acrylic acid ester, perfluoro n-butyl (meth) acrylic acid ester, perfluoro i-butyl (meth) acrylic acid ester, perfluoro t-butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylic acid ester, 1- (2,2,3,3,4,4 , 5,5-octafluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylate Luric acid ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, monofluorocyclopentyl (meth) acrylic acid ester, difluorocyclopentyl (meth) acrylic acid ester, perfluorocyclopentyl (Meth) acrylic acid ester, monofluorocyclohexyl (meth) acrylic acid ester, difluorocyclopentyl (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic acid ester, fluoronorbornyl (meth) acrylic acid ester, fluoroadamantyl (Meth) acrylic acid ester, fluorobornyl (meth) acrylic acid ester, fluoroisobornyl (meth) acrylic acid ester, fluorotricyclodecyl (meth) acrylic acid ester, fluoro Mention may be made of tetracyclododecene decyl (meth) acrylate and the like.

  [A] When a polymer has a structural unit (II-1), as a minimum of the content rate of a structural unit (II-1), it is 5 mol% with respect to all the structural units which comprise a [A] polymer. Is preferable, and 10 mol% is more preferable. On the other hand, as an upper limit of the said content rate, 40 mol% is preferable and 30 mol% is more preferable.

  [A] When a polymer has a structural unit (II-2), as a minimum of the content rate of a structural unit (II-2), it is 5 mol% with respect to all the structural units which comprise a [A] polymer. Is preferable, and 10 mol% is more preferable. On the other hand, as an upper limit of the said content rate, 40 mol% is preferable and 30 mol% is more preferable.

  [A] When the polymer has the structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 5 mol% with respect to all the structural units constituting the [A] polymer. Mole% is more preferable, and 15 mol% is more preferable. On the other hand, as an upper limit of the said content rate, 40 mol% is preferable, 30 mol% is more preferable, and 25 mol% is further more preferable. By making the content rate of structural unit (II) into the said range, the mass content rate of the fluorine atom of a [A] polymer can be adjusted more appropriately, As a result, the said radiation sensitive resin composition It is possible to further improve the development defect suppression property.

[Structural unit (III)]
The structural unit (III) includes an acid dissociable group and is a structural unit different from the structural unit (I). [A] Since the polymer has the structural unit (III), the solubility of the [A] polymer in the exposed portion of the resist film can be further increased. As a result, the development defect of the radiation-sensitive resin composition Inhibitory property can be further improved.

  Examples of the structural unit (III) include a structural unit represented by the following formula (3-1) (hereinafter also referred to as “structural unit (III-1)”) and a structure represented by the following formula (3-2). A unit (hereinafter also referred to as “structural unit (III-2)”).

In the above formula (3-1), ^{R 6} is a hydrogen atom, a fluorine atom, a fluorinated alkyl group of 1 to 4 alkyl groups or carbon atoms having 1 to 4 carbon atoms. R ⁷ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ⁸ and R ⁹ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or these groups are combined with each other, and the number of ring members 3 formed together with the carbon atom to which they are bonded. Represents -20 alicyclic structures.

In the above formula ^{(3-2), R 10} is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. L ² is a single bond, —CCOO— or —CONH—. R ¹¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹² and R ¹³ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms.

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

In the above formulas (3-1-1) to (3-1-4), R ^{6 to} R ⁹ have the same meaning as the above formula (3-1). n _p is each independently an integer of 1 to 4.

In the above formula ^(3-2-1), R 10 ^{to R 13} is as defined in the above formula (3-2).

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

In said formula, R < ⁶ > is synonymous with said formula (3-1).

  Specific examples of the structural unit (III-2) include structural units represented by the following formulas.

In said formula, R < ¹⁰ > is synonymous with said formula (3-2).

  As the structural unit (III-1), structural units derived from 1-alkylcyclopentan-1-yl (meth) acrylate, structural units derived from 2-cyclohexyl-2-propyl (meth) acrylate, and 2-alkyltetra A structural unit derived from cyclododecan-2-yl (meth) acrylate is preferred.

  As the structural unit (III-2), a structural unit derived from 4-t-butoxystyrene and a structural unit derived from 4- (1-cyclohexylethoxyethoxy) styrene are preferable.

  [A] When a polymer has a structural unit (III-1), as a minimum of the content rate of a structural unit (III-1), it is 5 mol% with respect to all the structural units which comprise a [A] polymer. Is preferable, 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. On the other hand, the upper limit of the content is preferably 40 mol%, more preferably 35 mol%, still more preferably 30 mol%, and particularly preferably 25 mol%.

  [A] When a polymer has a structural unit (III-2), as a minimum of the content rate of a structural unit (III-2), it is 5 mol% with respect to all the structural units which comprise a [A] polymer. Is preferable, 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. On the other hand, the upper limit of the content is preferably 40 mol%, more preferably 35 mol%, still more preferably 30 mol%, and particularly preferably 25 mol%.

  [A] When the polymer has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 5 mol% with respect to all the structural units constituting the [A] polymer. More preferably, mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. On the other hand, the upper limit of the content is preferably 40 mol%, more preferably 35 mol%, still more preferably 30 mol%, and particularly preferably 25 mol%.

  By making the said content rate into the said range, the development defect inhibitory property of the said radiation sensitive resin composition can be improved more.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof (except for those corresponding to the structural unit (I)). [A] When the polymer further has the structural unit (IV), the solubility in the developer can be adjusted to a more appropriate level.

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

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

  Among these, the structural unit (IV) includes a structural unit containing a norbornane lactone structure, a structural unit containing an oxynorbornane lactone structure, a γ-butyrolactone structure, a structural unit containing an ethylene carbonate structure, and a structural unit containing a norbornane sultone structure. Is preferred, a structural unit derived from norbornanelactone-yl (meth) acrylate, a structural unit derived from cyanonorbornanelactone-yl (meth) acrylate, a structural unit derived from oxynorbornanelactone-yl (meth) acrylate, butyrolactone-yl A structural unit derived from (meth) acrylate, a structural unit derived from ethylene carbonate-yl (meth) acrylate, and a structural unit derived from norbornane sultone-yl (meth) acrylate are more preferred.

  [A] When a polymer has a structural unit (IV), as a minimum of the content rate of a structural unit (IV), 5 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 10 More preferably, mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. On the other hand, the upper limit of the content is preferably 40 mol%, more preferably 35 mol%, still more preferably 30 mol%, and particularly preferably 25 mol%. By setting the content ratio of the structural unit (IV) within the above range, it is possible to adjust the solubility of the [A] polymer in the developer more appropriately.

[Structural unit (V)]
The structural unit (V) is a structural unit having an alcoholic hydroxyl group (except for those corresponding to the structural unit (I)). [A] When the polymer further has the structural unit (V), the solubility in the developer can be adjusted to a more appropriate level.

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

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

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

  [A] When a polymer has a structural unit (V), as a minimum of the content rate of a structural unit (V), 3 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 7 Mole% is more preferable, and 10 mol% is more preferable. On the other hand, as an upper limit of the said content rate, 40 mol% is preferable, 30 mol% is more preferable, and 20 mol% is further more preferable. By making the content rate of a structural unit (V) into the said range, the solubility to the developing solution of a [A] polymer can be adjusted more appropriately.

[Structural unit (VI)]
The structural unit (VI) is a structural unit containing a phenolic hydroxyl group. [A] When the polymer further has the structural unit (VI), the solubility in the developer can be adjusted to a more appropriate level. Furthermore, in the case of KrF exposure, EUV exposure, or electron beam exposure, the sensitivity of the radiation sensitive resin composition can be increased.

  Examples of the structural unit (VI) include a structural unit represented by the following formula (4) (hereinafter also referred to as “structural unit (VI-1)”).

In the formula ^{(4), R 14} is a hydrogen atom or a methyl group. L ³ is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹⁵ is a monovalent organic group having 1 to 20 carbon atoms. v is an integer of 0-2. w is an integer of 0-9. When w is 2 or more, the plurality of R ¹⁵ may be the same or different. x is an integer of 1 to 3.

  As the structural unit (VI), for example, structural units represented by the following formulas (4-1) to (4-6) (hereinafter also referred to as “structural units (VI-1) to (VI-6)”) and the like Is mentioned.

In the above formulas (4-1) to (4-6), R ¹⁴ has the same meaning as the above formula (4).

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

  [A] When the polymer has a structural unit (VI), the lower limit of the content ratio of the structural unit (VI) is preferably 10 mol% with respect to all the structural units constituting the [A] polymer. Mole% is more preferable, and 20 mol% is more preferable. On the other hand, as an upper limit of the said content rate, 40 mol% is preferable, 30 mol% is more preferable, and 25 mol% is further more preferable. By making the content rate of a structural unit (VI) into the said range, the solubility to the developing solution of a [A] polymer can be adjusted more appropriately. Moreover, the sensitivity in the case of KrF exposure, EUV exposure, or electron beam exposure can be improved more.

  [A] The polymer may have other structural units in addition to the structural units (I) to (VI). Examples of the other structural unit include a structural unit containing a non-dissociable alicyclic hydrocarbon group. [A] When a polymer has another structural unit, as an upper limit of the content rate of another structural unit, 30 mol% is preferable and 20 mol% is more preferable.

  [A] The lower limit of the content of the polymer is preferably 0.1% by mass, more preferably 0.5% by mass in terms of solid content, that is, with respect to the total solid content of the radiation-sensitive resin composition. 1% by mass is more preferable, and 3% by mass is particularly preferable. On the other hand, the upper limit of the content is preferably 20% by mass, more preferably 15% by mass, further preferably 10% by mass, and particularly preferably 6% by mass.

  [A] The lower limit of the content of the polymer is preferably 0.1 parts by mass, more preferably 1 part by mass, and further preferably 3 parts by mass with respect to 100 parts by mass of the polymer [B] described later. Part by mass is particularly preferred. On the other hand, the upper limit of the content is preferably 20 parts by mass, more preferably 15 parts by mass, further preferably 10 parts by mass, and particularly preferably 6 parts by mass.

  [A] By making content of a polymer into the said range, the uneven distribution of [A] polymer to the resist film surface layer can be accelerated | stimulated, As a result, the development defect of the said radiation sensitive resin composition Inhibitory property can be further improved.

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

  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; benzoyl peroxide, t-butyl hydroperoxide And peroxide radical initiators such as cumene hydroperoxide. Of these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is more preferred. These radical initiators can be used alone or in combination of two or more.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples 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 the above-mentioned polymerization, 40 ° C is preferred and 50 ° C is more preferred. On the other hand, the upper limit of the reaction temperature is preferably 150 ° C, more preferably 120 ° C. Moreover, as a minimum of the reaction time in the said superposition | polymerization, 1 hour is preferable and 2 hours is more preferable. On the other hand, 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) of the polymer is preferably 1,000, more preferably 2,000, still more preferably 4,000, and particularly preferably 7,000. On the other hand, the upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000. By making said Mw into the said range, the applicability | paintability of the said radiation sensitive resin composition can be improved, As a result, development defect inhibitory property can be improved more.

  [A] The lower limit of the number average molecular weight (Mn) of the polymer is preferably 1,000, more preferably 2,500, and still more preferably 3,500. On the other hand, the upper limit of Mn is preferably 40,000, more preferably 20,000, still more preferably 10,000, and particularly preferably 7,000.

  [A] The lower limit of the ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) of the polymer is usually 1, preferably 1.3 and more preferably 1.5. On the other hand, the upper limit of the Mw / Mn is preferably 5, more preferably 3, and even more preferably 2.

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

<[B] polymer>
[B] The polymer is a polymer having a smaller fluorine atom mass content than that of the [A] polymer, and its solubility in a developing solution is changed by the action of an acid. [B] The polymer usually constitutes the base polymer in the radiation-sensitive resin composition. The radiation sensitive resin composition may contain one or more [B] polymers. Here, the “base polymer” is a polymer that is a main component constituting the resist pattern, and is usually 50% by mass or more, preferably 60% by mass or more, based on the total polymer in the radiation-sensitive resin composition. Is a polymer.

  [B] The upper limit of the mass content of fluorine atoms in the polymer is preferably 5% by mass, more preferably 3% by mass, and even more preferably 2% by mass.

  Examples of the polymer [B] include a polymer having a structural unit containing an acid dissociable group (hereinafter also referred to as “structural unit (A)”).

  [B] In addition to the structural unit (A), the polymer may have a structural unit (B) containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof, and a structural unit containing an alcoholic hydroxyl group You may have other structural units other than (C), the structural unit (D) containing a phenolic hydroxyl group, and / or the said structural unit (A)-(D). [B] The polymer may have one or more of each structural unit.

[Structural unit (A)]
The structural unit (A) is a structural unit containing an acid dissociable group. Examples of the structural unit (A) include the structural unit (III) in the [A] polymer.

  As the structural unit (A), structural units (III-1) and (III-2) in the [A] polymer are preferable, and the structural units (III-1-1) to (III-1-4) and (III) 2-1) is more preferable, a structural unit derived from 2-alkyladamantan-2-yl (meth) acrylate, a structural unit derived from 1-alkylcyclopentan-1-yl (meth) acrylate, 2- (adamantane) -1-yl) propan-2-yl (meth) acrylate-derived structural unit, 2-alkyltetracyclododecan-2-yl (meth) acrylate-derived structural unit, 2- (cyclohexane-1-yl) propane Structural unit derived from 2-yl (meth) acrylate, structural unit derived from t-decane-yl (meth) acrylate, 1-alkylcyclohexane Tan-1-yl (meth) structural units derived from acrylate, p-t-butoxy structural units and p-2-(cyclohexylethoxy) derived from styrene structural units derived from ethoxy styrene is preferred.

  [B] When the polymer has a structural unit (A), the lower limit of the content ratio of the structural unit (A) is preferably 20 mol% with respect to all the structural units constituting the polymer. More preferably, mol% is more preferable, 40 mol% is further more preferable, and 50 mol% is especially preferable. On the other hand, as an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 60 mol% is further more preferable. By making the content rate of a structural unit (A) into the said range, the solubility with respect to the developing solution of a [B] polymer can be improved more, As a result, the development defect inhibitory property of the said radiation sensitive resin composition can be improved. It can be improved further.

[Structural unit (B)]
The structural unit (B) is a structural unit including a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. Examples of the structural unit (B) include the structural unit (IV) in the [A] polymer.

  The structural unit (B) is preferably a structural unit containing a lactone structure, more preferably a structural unit containing a norbornane lactone structure, a structural unit containing an oxynorbornane lactone structure, or a structural unit containing a γ-butyrolactone structure, and norbornane lactone-yl. Structural unit derived from (meth) acrylate, structural unit derived from cyano-substituted norbornanelactone-yl (meth) acrylate, structural unit derived from oxynorbornanelactone-yl (meth) acrylate, and γ-butyrolactone-3-yl (meta More preferred are structural units derived from acrylates.

  [B] When the polymer has a structural unit (B), the lower limit of the content ratio of the structural unit (B) is preferably 20 mol% with respect to all the structural units constituting the [B] polymer, 30 More preferably, mol% is more preferable, 40 mol% is further more preferable, and 50 mol% is especially preferable. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 60 mol% is further more preferable. By making the content rate of a structural unit (B) into the said range, the solubility to the developing solution of a [B] polymer can be adjusted more appropriately. Further, the adhesion between the resist pattern and the substrate can be further improved.

[Structural unit (C)]
The structural unit (C) is a structural unit containing an alcoholic hydroxyl group. Examples of the structural unit (C) include the structural unit (V) in the [A] polymer.

  As the structural unit (C), a structural unit derived from 3-hydroxyadamantan-1-yl (meth) acrylate is preferable.

  [B] When the polymer has a structural unit (C), the lower limit of the content ratio of the structural unit (C) is preferably 1 mol% with respect to all the structural units constituting the polymer [B]. The mol% is more preferable, and 8 mol% is more preferable. On the other hand, as an upper limit of the said content rate, 30 mol% is preferable, 20 mol% is more preferable, and 15 mol% is further more preferable. By making the content rate of a structural unit (C) into the said range, the solubility to the developing solution of a [B] polymer can be adjusted more appropriately.

[Structural unit (D)]
The structural unit (D) is a structural unit containing a phenolic hydroxyl group. Examples of the structural unit (D) include the structural unit (VI) in the [A] polymer.

  As the structural unit (D), a structural unit derived from hydroxystyrene is preferable.

  [B] When a polymer has a structural unit (D), as a minimum of the content rate of a structural unit (D), 1 mol% is preferable with respect to all the structural units which comprise a [B] polymer, 5 Mole% is more preferable, and 10 mol% is more preferable. On the other hand, the upper limit of the content is preferably 60 mol%, more preferably 40 mol%, and even more preferably 30 mol%. By making the content rate of a structural unit (D) into the said range, the solubility to the developing solution of a [B] polymer can be adjusted more appropriately.

[Other structural units]
Examples of the other structural unit include a structural unit containing a non-dissociable alicyclic hydrocarbon group, and a structural unit containing a polar group such as a carboxy group, a cyano group, a nitro group, and a sulfonamide group. As an upper limit of the content rate of another structural unit, 30 mol% is preferable with respect to all the structural units which comprise a [B] polymer, 20 mol% is more preferable, and 10 mol% is further more preferable.

  [B] The lower limit of the Mw of the polymer is preferably 1,500, more preferably 2,500, still more preferably 3,500, and particularly preferably 5,000. On the other hand, the upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 15,000, and particularly preferably 8,000. By setting the Mw in the above range, the solubility of the [B] polymer in the developer can be further adjusted to an appropriate level. As a result, the development defect suppression of the radiation-sensitive resin composition can be improved. It can be improved further.

  [B] The lower limit of Mn of the polymer is preferably 1,000, more preferably 2,000, and still more preferably 3,000. On the other hand, the upper limit of Mn is preferably 35,000, more preferably 20,000, still more preferably 10,000, and particularly preferably 5,000.

  [B] The lower limit of Mw / Mn of the polymer is usually 1 and preferably 1.4. On the other hand, the upper limit of the Mw / Mn is usually 5, preferably 3, preferably 2 and more preferably 1.8. By setting the Mw / Mn in the above range, it is possible to further reduce the undissolved residue of the [B] polymer in the developer, and as a result, the development defect suppression of the radiation sensitive resin composition is further improved. Can be made.

  [B] The lower limit of the content of the polymer is preferably 70% by mass and more preferably 80% by mass with respect to the total solid content in the radiation-sensitive resin composition. On the other hand, as a maximum of content of [B] polymer, 99 mass% is preferred, 95 mass% is more preferred, and 90 mass% is still more preferred.

<[B] Polymer Synthesis Method>
The [B] polymer can be synthesized, for example, by the same method as the above-described method for synthesizing the [A] polymer.

<[C] acid generator>
[C] The acid generator is a substance that generates an acid upon exposure. The generated acid dissociates the acid-dissociable group of the [A] polymer, [B] polymer, etc. to generate a carboxy group, etc., and the [A] polymer, [B] polymer, etc. into the developer. Since solubility changes, a resist pattern can be formed from the said radiation sensitive resin composition. As the inclusion form of the [C] acid generator in the radiation sensitive resin composition, a low molecular compound form (hereinafter also referred to as “[C] acid generator”) is incorporated as part of the polymer. Or both of these forms. The radiation-sensitive resin composition may contain one or more [C] acid generators.

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

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

  [C] Specific examples of the acid generator include compounds described in paragraphs [0080] to [0113] of JP-A-2009-134088.

  [C] The acid generator is preferably a compound represented by the following formula (5). [C] When the acid generator has the following structure, the diffusion length of the acid generated by exposure in the resist film is appropriately shortened by the interaction with the structural unit (A) of the polymer [B]. As a result, the lithography performance of the radiation sensitive resin composition can be improved.

In the above formula (5), R ^p1 is a monovalent group containing a ring structure having 6 or more ring members. R ^p2 is a divalent linking group. R ^p3 and R ^p4 are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ^p5 and R ^p6 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. n ^p1 is an integer of 0 to 10. n ^p2 is an integer of 0 to 10. n ^p3 is an integer of 1 to 10. When n ^p1 is 2 or more, the plurality of R ^p2 may be the same or different. When n ^p2 is 2 or more, the plurality of R ^p3 may be the same or different, and the plurality of R ^p4 may be the same or different. When n ^p3 is 2 or more, the plurality of R ^p5 may be the same or different, and the plurality of R ^p6 may be the same or different. X ⁺ is a monovalent radiation-sensitive onium cation.

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

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

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

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

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

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

A part or all of the hydrogen atoms ^{contained in} the ring structure of R ^p1 may be substituted with a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, An acyloxy group etc. are mentioned, Among these, a hydroxy group is preferable.

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

Examples of the divalent linking group represented by R ^p2 include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, and a divalent hydrocarbon group. The divalent linking group represented by R ^p2 is preferably a carbonyloxy group, a sulfonyl group, an alkanediyl group and a cycloalkanediyl group, more preferably a carbonyloxy group and a cycloalkanediyl group, a carbonyloxy group and a norbornanediyl group. A group is more preferred, and a carbonyloxy group is particularly preferred.

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

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p5 and R ^p6 include a fluorinated alkyl group having 1 to 20 carbon atoms. R ^p5 and R ^p6 are preferably a fluorine atom and a fluorinated alkyl group, more preferably a fluorine atom and a perfluoroalkyl group, still more preferably a fluorine atom and a trifluoromethyl group, and particularly preferably a fluorine atom.

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

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

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

The monovalent radiation-sensitive onium cation represented by X ⁺ is a cation that decomposes upon exposure to exposure light. In the exposed portion, sulfonic acid is generated from protons generated by the decomposition of the radiation-sensitive onium cation and sulfonate anions. Examples of the monovalent radiation-sensitive onium cation represented by X ⁺ include a sulfonium cation having a sulfur atom and an iodonium cation having an iodine atom. Among these, a cation represented by the following formula (X-1), a cation represented by the following formula (X-2), and a cation represented by the following formula (X-3) are preferable.

In the above formula (X-1), R ^a1 , R ^a2 and R ^a3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, substituted or unsubstituted. aromatic hydrocarbon group having 6 to 12 carbon atoms, or an -OSO ₂ -R ^P or _-SO 2 -R ^Q, or two or more are combined with each other of these groups, or a carbon atom they are attached The ring structure comprised with the carbon chain which may contain -S- between carbon-carbon bonds is represented. R ^P and R ^Q are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2 and k3 are each independently an integer of 0 to 5. R ^a1 to R ^a3 and, if a plurality ^{R P} and ^{R Q} are each plurality of ^R a1 ^{to R a3} and ^{R P} and ^{R Q} may each be the same or different.

In the above formula (X-2), R ^b1 represents a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon having 6 to 8 carbon atoms. It is a group. k4 is an integer of 0-7. If R ^b1 is plural, the plurality of R ^b1 may be the same or different, and plural R ^b1 is keyed, to form a ring structure composed together with the carbon atom or carbon chain thereof are bonded to each other It may be. R ^b2 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. k5 is an integer of 0-6. If R ^b2 is plural, the plurality of R ^b2 may be the same or different, and plural R ^b2 are keyed, to form a ring structure composed together with the carbon atom or carbon chain thereof are bonded to each other It may be. q is an integer of 0-3.

In the above formula (X-3), R ^c1 and R ^c2 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 6 12 aromatic hydrocarbon group, or an -OSO ₂ -R ^R or _-SO 2 -R ^S, or two or more are combined with each other of these groups, a carbon atom or carbon they are bonded - carbon The ring structure comprised with the carbon chain which may contain -S- between bonds is represented. R ^R and R ^S are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k6 and k7 are each independently an integer of 0 to 5. R ^{c1, R} c2, ^R when ^R and ^{R S} is plural respective plurality of ^{R c1,} R c2, ^{R R} and ^{R S} may have respectively the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^{a1 to} R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. Is mentioned.

Examples of the unsubstituted branched alkyl group represented by R ^{a1 to} R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include i-propyl group, i-butyl group, sec-butyl group, t- A butyl group etc. are mentioned.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^{a1 to} R ^a3 , R ^c1 and R ^c2 include aryl groups such as phenyl group, tolyl group, xylyl group, mesityl group and naphthyl group; benzyl group and phenethyl group And an aralkyl group such as a group.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^b1 and R ^b2 include a phenyl group, a tolyl group, and a benzyl group.

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

R ^{a1 to} R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, -OSO ₂ -R ^T and _-SO 2 -R ^T, more preferably a monovalent aromatic hydrocarbon group having a fluorinated alkyl group and unsubstituted, more preferably a fluorinated alkyl group. R ^T is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

  As k1, k2, and k3 in the formula (X-1), integers of 0 to 2 are preferable, 0 or 1 is more preferable, and 0 is more preferable.

  As k4 in the formula (X-2), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 1 is more preferable. k5 is preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0.

  As k6 and k7 in the formula (X-3), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is more preferable.

X ⁺ is preferably a cation represented by the above formula (X-1), more preferably a triphenylsulfonium cation.

  Examples of the acid generator represented by the above formula (5) include compounds represented by the following formulas (5-1) to (5-13) (hereinafter “compounds (5-1) to (5-13)”. Also).

In the above formulas (5-1) to (5-13), X ⁺ has the same meaning as in the above formula (5).

  [C] Among these, the acid generator is preferably an onium salt compound, more preferably a sulfonium salt and a tetrahydrothiophenium salt, and the compound (5-1), the compound (5-2), and the compound (5-12). And compound (5-13) are more preferable.

  When the [C] acid generator is a [C] acid generator, the lower limit of the content of the [C] acid generator is preferably 0.1 parts by mass with respect to 100 parts by mass of the [B] polymer, 0.5 mass parts is more preferable, 1 mass part is further more preferable, and 3 mass parts is especially preferable. On the other hand, the upper limit of the content is preferably 30 parts by mass, more preferably 20 parts by mass, further preferably 10 parts by mass, and particularly preferably 7 parts by mass. [C] By making content of an acid generator into the said range, the sensitivity of the said radiation sensitive resin composition can be raised more appropriately, As a result, the development defect inhibitory property of the said radiation sensitive resin composition Can be further enhanced.

<[D] solvent>
[D] Solvent dissolves at least [A] polymer, [B] polymer and [C] acid generator, and optionally contained [E] acid diffusion controller and [F] uneven distribution accelerator. There is no particular limitation as long as it is a dispersible solvent. The resin composition may contain one or more [D] solvents.

  [D] Examples of the solvent include alcohol solvents, ether solvents, ketone organic solvents, amide solvents, ester organic 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 1,2-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;
Examples thereof include carbonate solvents such as dimethyl carbonate and diethyl 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.

  Among these, 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, and propylene glycol. Monomethyl ether acetate and cyclohexanone are particularly preferred.

<[E] Acid diffusion controller>
The said radiation sensitive resin composition may contain an [E] acid diffusion control body as needed. [E] The acid diffusion controller controls the diffusion phenomenon in the resist film of the acid generated from the [C] acid generator by exposure, and has an effect of suppressing an undesirable chemical reaction in the non-exposed portion. Moreover, the said radiation sensitive resin composition improves storage stability by containing an [E] acid diffusion control body. Further, the radiation-sensitive resin composition contains [E] an acid diffusion controller, whereby the resolution of the resist pattern is further improved, and the resist pattern line due to fluctuations in the holding time from exposure to development processing. Process stability is improved by suppressing the width change. [E] The content of the acid diffusion controller in the radiation-sensitive resin composition is incorporated as a part of the polymer even in the form of a free compound (hereinafter referred to as “[E] acid diffusion controller”). Either of these forms may be used. The radiation-sensitive resin composition may contain one or more [E] acid diffusion controllers.

  [E] Examples of the acid diffusion controller include a compound represented by the following formula (6) (hereinafter also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (I)”). "Nitrogen-containing compound (II)"), compounds having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compound (III)"), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, etc. It is done.

In the above formula (6), R ¹⁸ , R ¹⁹ and R ²⁰ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or A substituted or unsubstituted 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; aromatic amines such as aniline. It is done.

  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 and pyrazole.

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

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

In the above formula (7-1) and formula (7-2), R ^{21 to} R ²⁵ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group, or a halogen atom. E ⁻ and Q ⁻ are each independently an OH ⁻ , R ^α —COO ⁻ , R ^α —SO ₃ ^— or an anion represented by the following formula (7-3). R ^α is an alkyl group, an aryl group, or an aralkyl group.

In the formula ^{(7-3), R 26} is an alkyl group or a fluorinated alkyl group or an alkoxy group or a fluorinated alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms. u is an integer of 0-2. When u is 2, the plurality of R ²⁶ may be the same or different.

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

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

  When the said radiation sensitive resin composition contains an [E] acid diffusion control agent, as a minimum of content of [E] acid diffusion control agent, it is 0.1 with respect to 100 mass parts of [B] polymers. Part by mass is preferable, 1 part by mass is more preferable, and 5 parts by mass is more preferable. On the other hand, as an upper limit of the said content, 20 mass parts is preferable, 15 mass parts is more preferable, and 10 mass parts is further more preferable. [E] By making content of an acid diffusion control agent into the said range, the lithography performance of the said radiation sensitive resin composition can be improved more.

<[F] Localization promoter>
[F] The uneven distribution accelerator has an effect of more efficiently unevenly distributing the [A] polymer, which is a fluorine atom-containing polymer, on the resist film surface. By containing the [F] uneven distribution accelerator in the radiation sensitive resin composition, the content of the [A] polymer can be reduced as compared with the conventional case. Therefore, while maintaining the lithography performance of the radiation-sensitive resin composition, the elution of components from the resist film to the immersion medium can be further suppressed by improving the hydrophobicity of the resist film surface, or the immersion can be performed by high-speed scanning. Exposure can be performed at a higher speed, and as a result, immersion-derived defects such as watermark defects can be suppressed. Examples of the [F] uneven distribution promoter include low molecular compounds having a relative dielectric constant of 30 to 200 and a boiling point of 100 ° C. at 1 atm. Specific examples of such compounds include lactone compounds, carbonate compounds, nitrile compounds, and polyhydric alcohols. The radiation-sensitive resin composition may contain one or more [F] uneven distribution accelerators.

  Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, 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.

  [F] The lower limit of the content of the uneven distribution accelerator is preferably 10 parts by weight, more preferably 15 parts by weight, and 20 parts by weight with respect to 100 parts by weight of the total amount of the polymer in the radiation-sensitive resin composition. Is more preferable, and 25 parts by mass is more preferable. On the other hand, the upper limit of the content is preferably 500 parts by mass, more preferably 300 parts by mass, further preferably 200 parts by mass, and particularly preferably 100 parts by mass.

<Other optional components>
The radiation-sensitive resin composition may contain other optional components in addition to the components [A] to [F]. As said other arbitrary component, polymers other than [A] polymer and [B] polymer, surfactant, an alicyclic skeleton containing compound, a sensitizer, etc. are mentioned, for example. 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 diacrylate. Nonionic surfactants such as stearate; commercially available products include KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, Tochem Products), MegaFuck F171, F173 (above, DIC), Florard FC430, FC431 (above, Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, Asahi Glass) It is done. As content of the said surfactant, it is 2 mass parts or less normally with respect to 100 mass parts of [A] polymers.

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

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

(Sensitizer)
The sensitizer exhibits an action of increasing the amount of acid generated from the [C] acid generator and the like, and has an effect of improving the “apparent sensitivity” of the resin composition.

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

<Method for preparing radiation-sensitive resin composition>
For example, the radiation-sensitive resin composition is a mixture of [A] polymer, [B] polymer, [C] acid generator and [D] solvent, and optional components contained as necessary. Preferably, the resultant mixture can be prepared by filtering through a membrane 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% is more preferred, 1.5 mass% is still more preferred, and 3 mass% is especially preferred. On the other hand, the upper limit of the solid content concentration is preferably 50% by mass, more preferably 30% by mass, further preferably 15% by mass, and particularly preferably 6% by mass.

<Resist pattern formation method>
The resist pattern forming method of the present invention includes a step of forming a resist film (hereinafter also referred to as “resist film forming step”), a step of exposing the resist film (hereinafter also referred to as “exposure step”), and the exposure. And a step of developing the resist film (hereinafter also referred to as “developing step”).

[Resist film forming step]
In this step, a resist film is formed from the radiation sensitive resin composition. Examples of the substrate on which the resist film is formed include conventionally known ones such as a silicon wafer, silicon dioxide, and a wafer coated with aluminum. Further, an organic or inorganic antireflection film (lower antireflection film) is formed on the substrate by a known method disclosed in, for example, Japanese Patent Publication No. 6-12452 and Japanese Patent Application Laid-Open No. 59-93448. May be. Examples of the coating method include spin coating (spin coating), cast coating, and roll coating. After application, it is preferable to perform soft baking (SB) to volatilize the solvent in the coating film as necessary. As a minimum of the temperature of SB, 60 degreeC is preferable and 80 degreeC is more preferable. On the other hand, the upper limit of the temperature of SB is preferably 140 ° C., more preferably 120 ° C. Further, the lower limit of the SB time is preferably 5 seconds, and more preferably 10 seconds. On the other hand, the upper limit of the SB time is preferably 600 seconds, and more preferably 300 seconds. Furthermore, as a minimum of the average thickness of the resist film formed, 5 nm is preferable and 10 nm is more preferable. On the other hand, the upper limit of the average thickness is preferably 1,000 nm, and more preferably 500 nm.

[Exposure process]
In this step, the resist film formed in the resist film forming step is exposed by irradiating exposure light through a photomask or the like. As the exposure light, electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays and γ rays; charged particle beams such as electron beams and α rays, depending on the line width of the target pattern. Etc. Among these, far ultraviolet rays are preferable, ArF excimer laser light (wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm) are more preferable, and ArF excimer laser light is more preferable.

  The exposure is preferably performed through an immersion medium. That is, the exposure is preferably immersion exposure. Examples of the immersion medium include water and a fluorine-based inert liquid. The immersion medium is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient that is as small as possible so as to minimize distortion of the optical image projected onto the film. In the case of excimer laser light (wavelength 193 nm), it is preferable to use water from the viewpoints of availability and easy handling in addition to the above-described viewpoints. The water used is preferably distilled water. When water is used, an additive that decreases the surface tension of water and increases the surface activity may be added in a small proportion. This additive is preferably one that does not dissolve the resist film on the wafer and can ignore the influence on the optical coating on the lower surface of the lens.

  When water is used as the immersion medium, the lower limit of the receding contact angle with water on the surface of the formed resist film is preferably 75 °, more preferably 78 °, still more preferably 81 °, and particularly preferably 85 °. 90 ° is even more particularly preferred. On the other hand, the upper limit of the receding contact angle is usually 100 °. By setting the receding contact angle within the above range, scanning can be performed at higher speed in the immersion exposure.

  After the exposure, post-exposure baking (PEB) is performed, and in the exposed portion of the resist film, dissociation of the acid-dissociable group of the [B] polymer or the like by the acid generated from the [C] acid generator by exposure. Is preferably promoted. This PEB can increase the difference in solubility in the developer between the exposed area and the unexposed area. As a minimum of the temperature of PEB, 50 degreeC is preferable and 80 degreeC is more preferable. On the other hand, as an upper limit of the temperature of PEB, 180 degreeC is preferable and 130 degreeC is more preferable. Further, the lower limit of the PEB time is preferably 5 seconds, and more preferably 10 seconds. On the other hand, the upper limit of the PEB time is preferably 600 seconds, and more preferably 300 seconds.

[Development process]
In this step, the resist film exposed in the exposure step is developed. Thereby, a predetermined resist pattern can be formed. In general, after development, the substrate is washed with a rinse solution such as water or alcohol and then dried. The development method may be alkali development or organic solvent development, but alkali development is preferred. In the case of alkali development, since it is preferable to further promote dissociation of the acid dissociable group of the polymer, the benefits of the present invention are further increased.

  As the developer used for the development, in the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n -Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, Examples include alkaline aqueous solutions in which at least one alkaline compound such as 1,5-diazabicyclo- [4.3.0] -5-nonene is dissolved. Among these, a TMAH aqueous solution is preferable, and a 2.38 mass% TMAH aqueous solution is more preferable.

  In the case of organic solvent development, examples of the developer include organic solvents such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, or solvents containing organic solvents. . As said organic solvent, the 1 type (s) or 2 or more types of the solvent enumerated as the [D] solvent of the said radiation sensitive resin composition mentioned above are mentioned, for example. 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. As a minimum of content of the organic solvent in a developing solution, 80 mass% is preferred, 90 mass% is more preferred, 95 mass% is still more preferred, and 99 mass% is especially preferred. Examples of components other than the organic solvent in the developer include water and silicone oil.

  As a developing method, for example, a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (dip method), a method in which the developer is raised on the surface of the substrate by surface tension and is left stationary for a certain time (paddle method) ), A method of spraying the developer on the substrate surface (spray method), a method of continuously applying the developer while scanning the developer coating nozzle on the substrate rotating at a constant speed (dynamic dispensing method) Etc.

  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.

[Mw and Mn]
Mw and Mn of the polymer were measured by GPC under the following conditions.
GPC column: 2 “G2000HXL”, 1 “G3000HXL”, and 1 “G4000HXL” manufactured by Tosoh Corporation Column temperature: 40 ° C.
Elution solvent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[ ¹³ C-NMR analysis]
¹³ C-NMR analysis was performed using a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.) and deuterated chloroform as a measurement solvent.

<Synthesis of compounds>
The compound was synthesized according to the following scheme.

[Synthesis Example 1] (Synthesis of Compound (Z-1))
To a 1,000 mL round bottom flask was added 34.95 g (0.55 mol) of copper powder, 91.35 g (0.45 mol) of ethyl bromodifluoroacetate, 21.03 g (0.25 mol) of ethyl vinyl ketone, and 300 g of tetrahydrofuran. Heated at 60 ° C. Subsequently, 14.6 g (0.125 mol) of tetramethylethylenediamine and 13.5 g (0.225 mol) of acetic acid were added, and the mixture was heated to reflux for 8 hours. After cooling to room temperature, an aqueous ammonium chloride solution was added, and the reaction product was extracted with ethyl acetate. Insoluble matters were removed by Celite filtration, and the obtained solution was evaporated to obtain 56.0 g of a crude product (z-1) represented by the following formula (z-1). The crude product was used in the next reaction without further purification.

  Next, 20.0 g (96 mmol) of the crude product (z-1) obtained above and 50 mL of acetonitrile were added to a 300 mL round bottom flask and stirred in a water bath. A 5 mass% aqueous solution containing 2.42 g (101 mmol) of lithium hydroxide was slowly added dropwise to the stirred solution. After completion of dropping, the mixture was stirred at room temperature for 10 hours. Concentrated hydrochloric acid was added until the pH was 2 or less, and then the reaction product was extracted with dichloromethane. By distilling off the solvent, 13.84 g of a crude product (z-2) represented by the following formula (z-2) was obtained. The crude product was used in the next reaction without further purification.

  Next, 15.00 g (84 mmol) of the crude product (z-2) obtained above and 75 mL of THF were added to a 300 mL round bottom flask and stirred in an ice bath. To the stirred solution, 168 mL (168 mmol) of MeMgBr solution (1.0 M THF solution) was slowly added dropwise. After completion of dropping, the mixture was stirred at room temperature for 5 hours. Thereafter, the reaction was stopped with dilute hydrochloric acid, and the reaction product was extracted with acetic acid. By distilling off the solvent, 9.81 g of a crude product (z-3) represented by the following formula (z-3) was obtained. The crude product was used in the next reaction without further purification.

  To the 200 mL round bottom flask, 9.00 g (46 mmol) of the crude product (z-3) obtained above, 50 mL of toluene and 0.3 g of dimethylformamide were added, and the mixture was cooled and stirred in an ice bath. 6.98 g (55 mmol) of oxalyl chloride was slowly added dropwise to the stirred solution. After completion of dropping, the mixture was stirred at 0 ° C. for 15 minutes and then stirred at room temperature for 3 hours. After distilling off the solvent and excess oxalyl chloride, 25 mL of toluene was added to obtain Solution (I).

  To a 300 mL round bottom flask were added 5.50 g (55 mmol) of trifluoroethanol, 5.60 g (55 mmol) of triethylamine and 25 g of toluene, and the mixture was cooled and stirred in an ice bath. The prepared solution (I) was slowly added dropwise to the stirred solution. After completion of dropping, the mixture was stirred at 0 ° C. for 1 hour, and then stirred at room temperature for 8 hours. After the solvent was distilled off, ethyl acetate was added, and insoluble matters were removed by Celite filtration. The obtained solution was washed with water three times, and then the solvent was distilled off. By purification by column chromatography, 13.77 g (yield 90%) of an ester form (z-4) represented by the following formula (z-4) was obtained.

  To a 200 mL round bottom flask were added 5.77 g (40 mmol) of monomethyl itaconate, 40 mL of toluene and 0.2 g of dimethylformamide, and the mixture was cooled and stirred in an ice bath. To the stirred solution, 6.09 g (48 mmol) of oxalyl chloride was slowly added dropwise. After completion of dropping, the mixture was stirred at 0 ° C. for 15 minutes and then stirred at room temperature for 3 hours. After distilling off the solvent and excess oxalyl chloride, 20 mL of toluene was added to obtain a solution (II).

  To a 300 mL round bottom flask, 13.35 g (48 mmol) of ester (z-4), 4.85 g (48 mmol) of triethylamine and 25 g of toluene were added, and the mixture was cooled and stirred in an ice bath. The prepared solution (II) was slowly added dropwise to the stirred solution. After completion of dropping, the mixture was stirred at 0 ° C. for 1 hour, and then stirred at room temperature for 8 hours. After the solvent was distilled off, ethyl acetate was added, and insoluble matters were removed by Celite filtration. The obtained solution was washed with water three times, and then the solvent was distilled off. By purifying by column chromatography, 15.52 g (yield 80%) of a compound (Z-1) which is an ester represented by the following formula (Z-1) was obtained.

[Synthesis Examples 2 to 12] (Synthesis of Compounds (Z-2) to (Z-12))
Compounds (Z-2) to (Z-12) represented by the following formulas were synthesized by the same method as in Synthesis Example 1 except that the corresponding reagents were changed.

<Synthesis of polymer>
In addition to the compounds (Z-1) to (Z-12), a compound which is a monomer used for the synthesis of [A] polymer (water repellent polymer additive) and [B] polymer (base polymer) (M-1) to (M-11) and (ci-1) to (ci-2) are shown in the following formula.

  In addition, each of the compounds (Z-1) to (Z-12) gives the structural unit (I) of the [A] polymer. Compounds (M-1) to (M-7) give the structural unit (III) of the [A] polymer or the structural unit (A) of the [B] polymer, respectively. Compounds (M-8) to (M-11) each give a structural unit (B) of the [B] polymer.

[Synthesis Example 13] (Synthesis of Polymer (A-1))
26.75 g (80 mol%) of the compound (Z-1) and 3.25 g (20 mol%) of the compound (M-2) were dissolved in 30 g of 2-butanone, and further dimethyl 2, as a radical polymerization initiator. A monomer solution was prepared by dissolving 0.28 g (1.71 mmol) of 2′-azobisisobutyrate. Next, a 300 mL three-necked flask containing 30 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the monomer solution prepared above was added dropwise over 3 hours using a dropping funnel. . The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled to 30 ° C. or less by water cooling. After the cooled polymerization reaction liquid was transferred to a 2 L separatory funnel, 450 g of n-hexane and 90 g of acetonitrile were added and mixed, and allowed to stand for 30 minutes. Thereafter, the lower layer was recovered and solvent substitution into propylene glycol monomethyl ether acetate was performed to obtain a propylene glycol monomethyl ether acetate solution of polymer (A-1) (yield 80%). Mw of the polymer (A-1) was 9,100, and Mw / Mn was 1.72. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from the compound (Z-1) and the compound (M-2) were 77.1 mol% and 22.9 mol%, respectively.

[Synthesis Examples 14 to 31 and Comparative Synthesis Examples 1 and 2] (Synthesis of Polymers (A-2) to (A-19) and (a-1) to (a-2))
Polymers (A-2) to (A-19) and (a-1) to (a-) were used in the same manner as in Synthesis Example 13 except that the types and amounts of monomers shown in Table 1 were used. 2) was obtained. In Table 1, “-” indicates that the corresponding monomer was not used. The total mass of the monomers used was 30 g. Table 1 below shows the content (mol%), yield (%), Mw, and Mw / Mn of each structural unit of these polymers.

[Synthesis Example 34] (Synthesis of Polymer (B-3))
Compound (M-6) 51.0 g (55 mol%) and compound (M-9) 49.0 g (45 mol%) were dissolved in 150 g of 2-butanone, and 3.62 g of AIBN as a radical polymerization initiator ( A monomer solution was prepared by dissolving 5 mol% of the total number of moles of the compounds (M-6) and (M-9). Next, a 100 mL three-necked flask containing 50 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. . The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled to 30 ° C. or less by water cooling. The cooled polymerization reaction solution was put into 1,500 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 300 g of methanol, filtered, and dried at 50 ° C. for 17 hours to obtain 81 g of a white powdery polymer (B-3) (yield 81%). Mw of the polymer (B-3) was 6,900, and Mw / Mn was 1.55. As a result of ¹³ C-NMR analysis, the content ratios of structural units derived from the compounds (M-6) and (M-9) were 53.3 mol% and 46.7 mol%, respectively.

[Synthesis Examples 32 and 33] (Synthesis of Polymers (B-1) and (B-2))
Polymers (B-1) and (B-2) were synthesized in the same manner as in Synthesis Example 34, except that each type and amount of each monomer shown in Table 2 were used. The total mass of the monomers used was 100 g. Table 2 below shows the content, yield (%), Mw, and Mw / Mn of each structural unit of these polymers.

<Preparation of radiation-sensitive resin composition>
Each component used for preparation of a radiation sensitive resin composition is shown below.

[[C] acid generator]
Each structural formula is shown below.
C-1: Triphenylsulfonium 3-hydroxyadamantan-1-ylmethyloxycarbonyldifluoromethanesulfonate C-2: Triphenylsulfonium adamantane-1-ylcarbonyloxy-1,1,3,3,3-pentafluoropropane- 1-sulfonate C-3: 4-butoxynaphthalen-1-yltetrahydrothiophenium 3-hydroxyadamantan-1-ylmethyloxycarbonyldifluoromethanesulfonate C-4: triphenylsulfonium 2- (adamantan-1-yl)- 1,1-difluoroethanesulfonate

[[D] solvent]
D-1: Propylene glycol monomethyl ether acetate D-2: Cyclohexanone D-3: γ-Butyrolactone

[[E] acid diffusion controller]
Each structural formula is shown below.
E-1: Triphenylsulfonium 10-camphorsulfonate E-2: N- (undecan-1-ylcarbonyloxyethyl) morpholine E-3: N- (t-amyloxycarbonyl) -4-hydroxypiperidine

[Example 1] (Preparation of radiation-sensitive resin composition (J-1))
[A] 5 parts by mass of the polymer (A-1) as a polymer, 100 parts by mass of the polymer (B-1) as a [B] polymer, and [C] (C-1 as an acid generator) ) 5.1 parts by mass, (D-1) 1,980 parts by mass as [D] solvent, (D-2) 850 parts by mass and (D-3) 100 parts by mass, and [E] acid diffusion control 7.9 parts by mass of (E-1) as an agent was mixed, and the obtained mixed solution was filtered through a membrane filter having a pore size of 0.2 μm to prepare a radiation sensitive resin composition (J-1).

[Examples 2 to 23 and Comparative Examples 1 and 2] (Preparation of radiation-sensitive resin compositions (J-2) to (J-23) and (CJ-1) to (CJ-2))
The radiation-sensitive resin compositions (J-2) to (J-23) and (CJ-1) to (CJ) were the same as in Example 1 except that the types and contents shown in Table 3 were used. -2) was prepared.

<Evaluation of Radiation Sensitive Resin Compositions (J-1) to (J-23) and (CJ-1) to (CJ-2)>
About the prepared radiation sensitive resin compositions (J-1) to (J-23) and (CJ-1) to (CJ-2), a resist film and a resist pattern are formed as follows, and a receding contact angle is formed. In addition, evaluation of development defect suppression was performed. The evaluation results are shown in Table 4 below.

[Backward contact angle after SB]
A radiation sensitive resin composition (J-1) was spin-coated on an 8-inch silicon wafer, and SB was performed at 110 ° C. for 60 seconds to form a resist film having an average thickness of 110 nm.

  The receding contact angle (°) was measured using a receding contact angle measuring device (“DSA-10” manufactured by KRUSS) under the conditions of a temperature of 23 ° C., a relative humidity of 45%, and 1 atm. In this measurement, first, the needle was washed with acetone and isopropyl alcohol, then water was injected into the needle, and the silicon wafer on which the resist film was formed as a measurement target was set on the wafer stage of the receding contact angle measurement device. . Thereafter, the height of the stage is adjusted so that the distance between the resist film surface and the tip of the needle is 1 mm or less, and water is discharged from the needle to form a 20 μL water droplet on the wafer. While suctioning at a rate of 10 μL / min for 180 seconds, the contact angle was measured every second. A total of 20 contact angles were measured from the time when the contact angle was stabilized, and the average value was defined as “retreat contact angle after SB (°)”. The receding contact angle after SB indicates that the larger the value, the better the water repellency of the surface. The case of 75 ° or more is “A (good)” and the case of less than 75 ° is “B (bad). Can be evaluated.

[Backward contact angle after development]
A radiation-sensitive resin composition (J-1) was spin-coated on an 8-inch silicon wafer, and SB was performed at 110 ° C. for 60 seconds to form a resist film having an average thickness of 110 nm. Thereafter, development was performed with a 2.38 mass% TMAH aqueous solution for 30 seconds using a developing device (“Clean Track ACT8” manufactured by Tokyo Electron Ltd.). Thereafter, it was rinsed with pure water for 15 seconds, shaken off at 2,000 rpm, and dried. The receding contact angle of the resist film after development was measured using the receding contact angle measuring device in the same manner as the above-mentioned “receding contact angle after SB”, and was defined as “backing contact angle after development (°)”. The receding contact angle after development indicates that the smaller the numerical value, the better the surface wettability, indicating that “A (good)” when the angle is less than 10 ° and “B (bad) when the angle is 10 ° or more. Can be evaluated.

  In place of the radiation-sensitive resin composition (J-1), the radiation-sensitive resin compositions (J-2) to (J-23) and (CJ-1) to (CJ-2) are used, and similarly after SB And the receding contact angle after development was measured.

[Development Defect Suppression (Blob Defect)]
A coating film is formed with a radiation sensitive resin composition (J-1) on a 12-inch silicon wafer on which an underlayer antireflection film is formed with a composition for forming an underlayer antireflection film (“ARC66” of Nissan Chemical Co., Ltd.) SB was performed at 120 ° C. for 50 seconds to form a resist film having an average thickness of 110 nm. Next, for this resist film, an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON) was used, and the target size had an average width of 38 nm under the conditions of NA = 1.3, ratio = 0.800, Dipole. The film was exposed through a mask pattern for forming a line and space (1L / 1S). After exposure, PEB was performed at 95 ° C. for 50 seconds. Then, it developed for 10 second with 2.38 mass% tetramethylammonium hydroxide aqueous solution with the GP nozzle of the image development apparatus ("Clean track ACT8" of Tokyo Electron). Thereafter, rinsing was performed with pure water for 15 seconds, and the liquid was spun off and dried at 2,000 rpm to form a positive resist pattern. At this time, the exposure amount for forming 1 L / 1S having an average width of 38 nm was determined as the optimum exposure amount. With this optimum exposure amount, 1 L / 1S having an average line width of 38 nm was formed on the entire surface of the wafer, and this was used as a wafer for defect inspection. A scanning electron microscope (Hitachi High-Technologies “CC-4000”) was used for length measurement. The number of defects on the defect inspection wafer was measured using a defect inspection apparatus (“KLA2810” manufactured by KLA-Tencor). In the measurement, the location where the unmelted residue of the resist film was observed was defined as a blob defect, and the number of blob defects was measured. The case where the number of detected blob defects is 100 or less is “A (good)”, the case where the number is more than 100 and 200 or less is “B (slightly good)”, and the case where the number exceeds 200 is “C (bad)” ".

[Development defect suppression (bridge defect)]
A wafer for defect inspection was prepared by the same operation as the evaluation of the blob defect described above, and the number of defects was measured using a defect inspection apparatus (“KLA2810” from KLA-Tencor). In the measurement, a bridge defect is targeted, and “A (good)” when the number of bridge defects detected when a resist pattern is formed is 10 or less, and “B ( Slightly good) ”, and the case of exceeding 50 was evaluated as“ C (defect) ”.

  Using the radiation sensitive resin compositions (J-2) to (J-23) and (CJ-1) to (CJ-2) in place of the radiation sensitive resin composition (J-1), the same operation is performed. The number of blob defects and bridge defects was measured.

  As is clear from the results in Table 4, the radiation-sensitive resin compositions of the examples had good receding contact angles and good development defect suppression properties both after SB and after development. From this, it is judged that the radiation sensitive resin composition of an Example can be used suitably for formation of a resist pattern, especially the formation of the resist pattern by immersion exposure. On the other hand, in the radiation sensitive resin composition of the comparative example, the receding contact angle after SB was good, but the receding contact angle after development was poor. Further, in the comparative example, the development defect suppression property was poor because the receding contact angle after development was poor.

  According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, the hydrophobicity of the resist film surface after development can be sufficiently reduced, and a resist pattern with few development defects can be formed. Therefore, these can be suitably used in the manufacturing process of semiconductor devices and the like that are expected to be further miniaturized in the future.

Claims (8)

A first polymer having a first structural unit represented by the following formula (1):
A second polymer having a smaller mass content of fluorine atoms than that of the first polymer and the solubility in a developing solution being changed by the action of an acid;
A radiation-sensitive resin composition comprising a radiation-sensitive acid generator and a solvent.

(In Formula (1), X ¹ and X ² are each independently a monovalent organic group having 1 to 30 carbon atoms. M is an integer of 1 to 3. When m is 2 or more. A plurality of X ¹ may be the same or different, provided that at least one of X ¹ and X ² is a group represented by the following formula (A): Y is a group having 1 to 5 carbon atoms. (M + 1) a valent chain hydrocarbon group.)

(In formula (A), Z ¹ and Z ² are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. L ¹ is a single bond, having 1 to 20 carbon atoms. A divalent chain hydrocarbon group or a divalent alicyclic hydrocarbon group having 3 to 20 ring members, two or more of Z ¹ , Z ² and L ¹ are combined with each other and bonded together. An alicyclic structure having 3 to 20 ring members and a carbon atom may be formed, and R ¹ and R ² are each independently a hydrogen atom, a fluorine atom, or a monovalent monovalent group having 1 to 20 carbon atoms. A hydrocarbon group or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, R ¹ and R ² are combined with each other, and a ring having 3 to 20 ring members configured together with the carbon atom to which they are bonded; optionally form a structure .R ³ is a monovalent hydrocarbon group or a C 1 -C 20 from 1 to 20 carbon atoms A monovalent fluorinated hydrocarbon group. Provided that at least one of R ^1, R ² and R ³ are a fluorine atom.) The radiation sensitive property according to claim ^1, wherein Z ¹ and L ¹ in the above formula (A) are combined with each other to form an alicyclic structure having 3 to 20 ring members composed of carbon atoms to which they are bonded. Resin composition.   The radiation-sensitive resin composition according to claim 1 or 2, wherein the group represented by the formula (A) is an acid-dissociable group.   The radiation sensitive resin composition according to claim 1, wherein m in the formula (1) is 1 and Y is a methanediyl group.   The radiation sensitive resin composition according to any one of claims 1 to 4, wherein a content ratio of the first structural unit with respect to all structural units constituting the first polymer is 50 mol% or more.   The radiation-sensitive resin composition according to claim 5, wherein a content ratio of the first structural unit with respect to all structural units constituting the first polymer is 100 mol%.   The radiation sensitive resin composition according to any one of claims 1 to 6, wherein the content of the first polymer is 0.1% by mass or more and 20% by mass or less in terms of solid content. Forming a resist film;
A step of exposing the resist film, and a step of developing the exposed resist film,
The resist pattern formation method which forms the said resist film with the radiation sensitive resin composition of any one of Claims 1-7.