JP6631397B2 - Radiation-sensitive resin composition, method for forming resist pattern, method for producing acid diffusion controller, and method for producing radiation-sensitive resin composition - Google Patents

Description

  The present invention relates to a radiation-sensitive resin composition, a method for forming a resist pattern, a method for producing an acid diffusion controller, and a method for producing a radiation-sensitive resin composition.

  The chemically amplified radiation-sensitive resin composition used for microfabrication by lithography generates an acid in the exposed portion by irradiation with far ultraviolet rays such as ArF excimer laser light, or charged particle beams such as an electron beam, and this acid is generated. A resist pattern is formed by causing a difference in a dissolution rate in a developer between an exposed portion and an unexposed portion by a chemical reaction using a catalyst.

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

  As the radiation-sensitive resin composition used in such an immersion exposure method, the elution of a radiation-sensitive acid generator or the like from the resist film to the immersion medium is suppressed, and the drainage of the resist film is improved. For the purpose, those containing a fluorine atom-containing polymer having high water repellency have been proposed (see WO 2007/116664).

International Publication No. 2007/116664

  However, since the fluorine atom-containing polymer has high water repellency, not only the immersion exposure method but also the EUV exposure may cause development defects such as blob defects due to adhesion of development residues. In addition, in the immersion exposure method, the occurrence of watermark defects that leave droplet marks on the resist pattern due to water (immersion medium) interposed during the immersion exposure remaining on the protective film is suppressed. Is also required. However, the above-mentioned conventional radiation-sensitive resin composition cannot satisfy these requirements.

  The present invention has been made in view of the above circumstances, the object thereof is a radiation-sensitive resin composition excellent in development defect suppression and watermark defect suppression, a resist pattern forming method using the same, An object of the present invention is to provide a method for producing an acid diffusion controller and a method for producing a radiation-sensitive resin composition.

（式（１）中、Ｘは、−Ｃ（＝Ｏ）Ｙ、−Ｃ（＝Ｏ）ＯＹ、−Ｃ（ＧＲ^Ｘ）_２Ｙ、−Ｃ（＝Ｏ）ＮＹＹ’、−Ｓ（＝Ｏ）_２Ｙ、−Ｓ（＝Ｏ）_２ＯＹ、−Ｓ（＝Ｏ）_２ＮＹＹ’、−Ｃ（＝Ｏ）ＯＣ（＝Ｏ）Ｙ又は−Ｃ（＝Ｏ）Ｎ（Ｙ）Ｃ（＝Ｏ）Ｙ’である。Ｇは、それぞれ独立して酸素原子又は硫黄原子である。Ｒ^Ｘは、それぞれ独立して、炭素数１〜２０の１価の有機基であるか、又は２つのＲ^ｘが互いに合わせられこれらが結合する−Ｇ−Ｃ−Ｇ−と共に環員数４〜２０の環構造を構成する。Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｙ及びＹ’は、それぞれ独立して、水素原子若しくは炭素数１〜２０の１価の有機基であるか、又はＹ若しくはＹ’とＲ^１、Ｙ若しくはＹ’とＲ^２、Ｙ若しくはＹ’とＲ^３又はＹ若しくはＹ’とＲ^４が、互いに合わせられこれらが結合する炭素原子と共に構成される環員数３〜２０の環構造を構成する。但し、Ｒ^１乃至Ｒ^４が１価の有機基である場合、Ｒ^１乃至Ｒ^４はフッ素原子を含まない。Ｒ^ｆ１及びＲ^ｆ２は、それぞれ独立して、フッ素原子又は炭素数１〜４の１価のフッ素化炭化水素基である。） The invention made to solve the above-mentioned problem is a radiation-sensitive resin containing a first polymer having an acid-dissociable group, a first compound having an anion represented by the following formula (1), and a solvent. A composition.

(In formula (1), X, -C (= O) Y, -C (= O) OY, -C (GR X) 2 Y, -C (= O) NYY ', - S (= O) _{2 Y, -S (= O)} 2 OY, -S (= O) 2 NYY ', - C (= O) OC (= O) Y or -C (= O) N (Y ) C (= O) G is each independently an oxygen atom or a sulfur atom, R ^X is each independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x are Together with —G—C—G—, which are combined with each other, they form a ring structure having 4 to 20 ring members, R ¹ , R ² , R ³ , R ⁴ , Y and Y ′ are each independently A hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or Y or Y ′ and R ¹ , Y or Y ′ and R ² , Y or Y ′ and R ^3, or Y or Y ′ and R ⁴ But To form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded, provided that when R ^{1 to} R ⁴ are monovalent organic groups, R ^{1 to} R ⁴ are each a fluorine atom R ^f1 and R ^f2 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms.)

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

（式（ａ）〜（ｅ）及び（１’）中、Ｘは、−Ｃ（＝Ｏ）Ｙ、−Ｃ（＝Ｏ）ＯＹ、−Ｃ（ＧＲ^Ｘ）_２Ｙ、−Ｃ（＝Ｏ）ＮＹＹ’、−Ｓ（＝Ｏ）_２Ｙ、−Ｓ（＝Ｏ）_２ＯＹ、−Ｓ（＝Ｏ）_２ＮＹＹ’、−Ｃ（＝Ｏ）ＯＣ（＝Ｏ）Ｙ又は−Ｃ（＝Ｏ）Ｎ（Ｙ）Ｃ（＝Ｏ）Ｙ’である。Ｇは、それぞれ独立して酸素原子又は硫黄原子である。Ｒ^Ｘは、それぞれ独立して、炭素数１〜２０の１価の有機基であるか、又は２つのＲ^ｘが互いに合わせられこれらが結合する−Ｇ−Ｃ−Ｇ−と共に環員数４〜２０の環構造を構成する。Ｒ^１’、Ｒ^３’、Ｒ^４’、Ｙ及びＹ’は、それぞれ独立して、水素原子若しくは炭素数１〜２０の１価の有機基であるか、又はＹ若しくはＹ’とＲ^１’、Ｙ若しくはＹ’とＲ^３’又はＹ若しくはＹ’とＲ^４’が、互いに合わせられこれらが結合する炭素原子と共に構成される環員数３〜２０の環構造を構成する。但し、Ｒ^１’、Ｒ^３’及び、Ｒ^４’が１価の有機基である場合、Ｒ^１’、Ｒ^３’及び、Ｒ^４’はフッ素原子を含まない。Ｒ^６は、炭素数１〜２０の１価の炭化水素基である。Ｒ^ｆ１及びＲ^ｆ２は、それぞれ独立して、フッ素原子又は炭素数１〜４の１価のフッ素化炭化水素基である。Ｑは、塩素原子、臭素原子又はヨウ素原子である。Ｚ^＋は、１価のカチオンである。Ｍ^―は、１価のアニオンである。） Yet another invention made to solve the above-mentioned problem is a method for producing an acid diffusion controller used in a radiation-sensitive resin composition, comprising a compound represented by the following formula (a) and a compound represented by the following formula (b): ) By a reaction with a compound represented by the following formula (c), and hydrolysis of an ester group of the compound represented by the following formula (c) to give a compound represented by the following formula (d) A step of obtaining a compound represented by the following formula (d) and a step of obtaining a compound represented by the following formula (1 ′) by reacting the compound represented by the following formula (d) with a salt represented by the following formula (e): A method for producing an acid diffusion controller comprising:

(In the formulas (a) to (e) and (1 ′), X represents —C (＝ O) Y, —C (＝ O) OY, —C (GR ^X ) ₂ Y, and —C (＝ O). _{NYY ', - S (= O} ) 2 Y, -S (= O) 2 OY, -S (= O) 2 NYY', - C (= O) OC (= O) Y or -C (= O) N is a group represented by N (Y) C (= O) Y ′, G is each independently an oxygen atom or a sulfur atom, and R ^X is each independently a monovalent organic group having 1 to 20 carbon atoms. Or two R ^x are joined together to form a ring structure having 4 to 20 ring members together with -GCCG- to which they are bonded, R ¹ ′, R ³ ′, R ⁴ ′, Y and Y ′ is each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or Y or Y ′ and R ¹ ′, Y or Y ′ and R ³ ′, or Y or Y ′ and ^{R 4} 'is, together with each other Which constitutes the ring structure formed ring members 3 to 20 together with the carbon atoms to which they are attached. However, R ^{1 ',} R 3' and, R 4 ^'when it is a monovalent organic group, R ^1' , R ³ ′ and R ⁴ ′ do not contain a fluorine atom, R ⁶ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ^f1 and R ^f2 are each independently a fluorine atom or A monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms, Q represents a chlorine atom, a bromine atom or an iodine atom, Z ⁺ represents a monovalent cation, and M ⁻ represents a monovalent anion. Is.)

（式（１）中、Ｘは、−Ｃ（＝Ｏ）Ｙ、−Ｃ（＝Ｏ）ＯＹ、−Ｃ（ＧＲ^Ｘ）_２Ｙ、−Ｃ（＝Ｏ）ＮＹＹ’、−Ｓ（＝Ｏ）_２Ｙ、−Ｓ（＝Ｏ）_２ＯＹ、−Ｓ（＝Ｏ）_２ＮＹＹ’、−Ｃ（＝Ｏ）ＯＣ（＝Ｏ）Ｙ又は−Ｃ（＝Ｏ）Ｎ（Ｙ）Ｃ（＝Ｏ）Ｙ’である。Ｇは、それぞれ独立して酸素原子又は硫黄原子である。Ｒ^Ｘは、それぞれ独立して、炭素数１〜２０の１価の有機基であるか、又は２つのＲ^ｘが互いに合わせられこれらが結合する−Ｇ−Ｃ−Ｇ−と共に環員数４〜２０の環構造を構成する。Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｙ及びＹ’は、それぞれ独立して、水素原子若しくは炭素数１〜２０の１価の有機基であるか、又はＹ若しくはＹ’とＲ^１、Ｙ若しくはＹ’とＲ^２、Ｙ若しくはＹ’とＲ^３又はＹ若しくはＹ’とＲ^４が、互いに合わせられこれらが結合する炭素原子と共に構成される環員数３〜２０の環構造を構成する。但し、Ｒ^１乃至Ｒ^４が１価の有機基である場合、Ｒ^１乃至Ｒ^４はフッ素原子を含まない。Ｒ^ｆ１及びＲ^ｆ２は、それぞれ独立して、フッ素原子又は炭素数１〜４の１価のフッ素化炭化水素基である。） Still another invention made to solve the above-mentioned problem is a radiation-sensitive method comprising a step of mixing a first polymer having an acid-dissociable group, a compound represented by the following formula (1), and a solvent. This is a method for producing a resin composition.

(In formula (1), X, -C (= O) Y, -C (= O) OY, -C (GR X) 2 Y, -C (= O) NYY ', - S (= O) _{2 Y, -S (= O)} 2 OY, -S (= O) 2 NYY ', - C (= O) OC (= O) Y or -C (= O) N (Y ) C (= O) G is each independently an oxygen atom or a sulfur atom, R ^X is each independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x are Together with —G—C—G—, which are combined with each other, they form a ring structure having 4 to 20 ring members, R ¹ , R ² , R ³ , R ⁴ , Y and Y ′ are each independently A hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or Y or Y ′ and R ¹ , Y or Y ′ and R ² , Y or Y ′ and R ^3, or Y or Y ′ and R ⁴ But To form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded, provided that when R ^{1 to} R ⁴ are monovalent organic groups, R ^{1 to} R ⁴ are each a fluorine atom R ^f1 and R ^f2 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms.)

  Here, the “organic group” refers to a group containing at least one carbon atom. The “acid dissociable group” is a group that substitutes a hydrogen atom such as a carboxy group and a hydroxy group, and is a group that dissociates by the action of an acid. The “number of ring members” refers to the number of atoms constituting a ring in an alicyclic structure, an aromatic ring structure, an aliphatic heterocyclic structure, or an aromatic heterocyclic structure.

  INDUSTRIAL APPLICABILITY The radiation-sensitive resin composition and the method of forming a resist pattern according to the present invention can be suitably used for pattern formation in semiconductor device manufacturing and the like where further miniaturization is expected to proceed.

<Radiation sensitive resin composition>
The radiation-sensitive resin composition contains a polymer [A], a compound [B] and a solvent [C]. The radiation-sensitive resin composition contains, as a suitable component, a [D] compound which generates sulfonic acid by the action of radiation, and an [E] polymer having a larger fluorine atom mass content than the [A] polymer. May be. Further, the radiation-sensitive resin composition may contain other optional components as long as the effects of the present invention are not impaired. The radiation-sensitive resin composition having the above configuration is excellent in development defect suppressing property, watermark defect suppressing property and storage stability. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I). According to the radiation-sensitive resin composition, the acid-dissociable group of the polymer [A] in the exposed portion is dissociated by the acid generated from the compound [B] by irradiation with radiation, and the exposed portion and the unexposed portion are dissociated. A difference occurs in the solubility in the developer, and as a result, a resist pattern can be formed. [A] The polymer is usually a base polymer in the radiation-sensitive resin composition. The “base polymer” refers to a polymer having the largest content among the polymers constituting the resist pattern, and preferably accounts for 50% by mass or more, more preferably 60% by mass or more.

  [A] In addition to the structural unit (I), the polymer may have a lactone structure, a cyclic carbonate structure, a sultone structure, or a structural unit containing a combination thereof (hereinafter, also referred to as “structural unit (II)”), a phenolic hydroxyl group. And a structural unit containing an alcoholic hydroxyl group (hereinafter also referred to as a “structural unit (IV)”), and preferably a structural unit (hereinafter also referred to as a “structural unit (IV)”). It may have other structural units other than I) to (IV). [A] The polymer may have one or more of these structural units.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group. Examples of the structural unit (I) include a structural unit represented by the following formula (3) (hereinafter, also referred to as “structural unit (I)”). [A] The polymer may have one or more structural units (I). Hereinafter, the structural unit (I) will be described.

In the above formula (3), R ^A1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. ^RA2 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^A3 and R ^A4 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms, or these groups are each other And represents a ring structure having 3 to 20 ring members which is combined with a carbon atom to which they are bonded.

  The “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. This “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure but is composed of only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. “Alicyclic hydrocarbon group” refers to a hydrocarbon group containing only an alicyclic structure as a ring structure and not containing an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Contains both hydrocarbon groups. However, it is not necessary to be constituted only by an 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 of only an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure.

R ^A1 is preferably a hydrogen atom and a methyl group, and more preferably a methyl group, from the viewpoint of copolymerizability of the monomer giving the structural unit (I).

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

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include an alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an i-propyl group;
Alkenyl groups such as an ethenyl group, a propenyl group and a butenyl group;
Alkynyl groups such as an ethynyl group, a propynyl group and a butynyl group are exemplified. Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, a methyl group, an ethyl group and an i-propyl group are further preferable, and an ethyl group is particularly preferable.

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

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

Examples of the monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by R ^A3 and R ^A4 include, for example, a terminal on the bond side of the monovalent hydrocarbon group exemplified as R ^A2 , R ^A3 and R ^A4. And a group having an oxygen atom bonded thereto.

The alicyclic structure of R ^A3 and a 3 to 20 carbon atoms with the carbon atom to which R ^A4 is combined they are bound together, for example, cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a norbornane structure, adamantane An alicyclic structure such as a structure;
Examples include aliphatic heterocyclic structures such as an oxacyclopentane structure, a thiacyclopentane structure, and an azacyclopentane structure. Among these, an alicyclic structure is preferable, and a cyclohexane structure is more preferable.

  Examples of the structural unit (I) include structural units represented by the following formulas (3-1) to (3-6) (hereinafter, also referred to as “structural units (I-1) to (I-6)”) and the like. Is mentioned.

In Formulas (3-1) to (3-5), R ^{A1 to} R ^A4 have the same meanings as in Formula (3).
In the above formula (3-1), i is an integer of 1 to 4.
In the above formula (3-3), j is an integer of 1 to 4.
In the above formula (3-6), ^{RA2 '} , ^RA3' and ^{RA4 '} are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms.

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

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

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

In the above formula, ^RA1 has the same ^{meaning as} in the above formula (3).

  As the structural unit (I), a structural unit derived from 1-alkyl-monocyclic cycloalkane-1-yl (meth) acrylate and a structural unit derived from 2-alkyl-polycyclic cycloalkane-2-yl (meth) acrylate And a structural unit derived from 2- (cycloalkane-yl) propan-2-yl (meth) acrylate, and a structural unit derived from 1-i-propylcyclopentan-1-yl (meth) acrylate, Structural unit derived from methylcyclohexane-1-yl (meth) acrylate, structural unit derived from 2-ethyl-adamantan-2-yl (meth) acrylate, 2-ethyl-tetracyclododecane-2-yl (meth) acrylate To a structural unit derived from 2- (adamantan-1-yl) propan-2-yl (meth) acrylate Structural units and 2- (cyclohexane-1-yl) propan-2-yl (meth) structural units derived from acrylate to come more preferable.

  The lower limit of the content of the structural unit (I) is preferably 10 mol%, more preferably 20 mol%, still more preferably 30 mol%, and more preferably 40 mol%, based on all the structural units constituting the polymer [A]. % Is particularly preferred. The upper limit of the content ratio is preferably 80 mol%, more preferably 75 mol%, further preferably 70 mol%, and particularly preferably 60 mol%. By setting the content ratio of the structural unit (I) in the above range, the LWR performance and the like of the radiation-sensitive resin composition can be further improved.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. [A] The polymer can further appropriately adjust the solubility in a developer by having the structural unit (II) in addition to the structural unit (I), and as a result, the radiation-sensitive resin composition The LWR performance and the like of the object can be further improved. Further, the adhesion between the resist pattern formed from the radiation-sensitive resin composition and the substrate can be improved.

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

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

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

  [A] When the polymer has the structural unit (II), the lower limit of the content of the structural unit (II) is preferably 10 mol%, more preferably 20 mol%, based on all the structural units in the polymer [A]. Is more preferable, 30 mol% is more preferable, and 40 mol% is particularly preferable. The upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, further preferably 65 mol%, and particularly preferably 60 mol%. When the content of the structural unit (II) is in the above range, the solubility of the polymer [A] in the developer can be adjusted more appropriately, and as a result, the LWR of the radiation-sensitive resin composition can be adjusted. Performance and the like can be further improved. Further, the adhesion between the obtained resist pattern and the substrate can be further improved.

[Structural unit (III)]
The structural unit (III) is a structural unit containing a phenolic hydroxyl group. When KrF excimer laser light, EUV, electron beam, or the like is used as radiation irradiated in the exposure step in the resist pattern forming method, the polymer [A] has the structural unit (III), so that the sensitivity can be further increased. Can be.

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

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

As the R ^14, from the viewpoint of copolymerizability of the monomer giving the structural unit (III), a hydrogen atom is preferable.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ¹⁵ include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon end of this hydrocarbon group, or a terminal on the bond side. And a group (g) containing a divalent hetero atom-containing group, and a group in which part or all of the hydrogen atoms contained in the hydrocarbon group and the group (g) are substituted with a hetero atom-containing group.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include the same groups as those described above for R ^A2 , R ^A3, and R ^A4 .

  Examples of the hetero atom contained in the hetero atom-containing group include a halogen atom such as a chlorine atom, a bromine atom and a fluorine atom, an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom, a phosphorus atom and the like. Among these, an oxygen atom, a sulfur atom, a nitrogen atom and a fluorine atom are preferred.

Examples of the divalent hetero atom-containing group contained between carbon-carbon or at the terminal on the bond side include, for example, -C (= O)-, -O-, -NR'-, -S-, -C (= S)-and groups obtained by combining these. R ′ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Incidentally, when these divalent heteroatom-containing group contains carbon atoms, the total number of carbon atoms R ¹⁵ has from 1 to 20. including those contained in these divalent heteroatom-containing group.

  Examples of the hetero atom-containing group which is substituted for part or all of the hydrogen atoms of the hydrocarbon group and the group (g) include, for example, an oxo group (基 O), a thioxo group (＝ S), a hydroxy group, a carboxy group , A sulfanyl group (-SH), an amino group, a cyano group, a halogen atom and the like.

  P is preferably an integer of 0 to 2, more preferably 0 and 1, and even more preferably 0.

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

  Examples of the structural unit (III) include structural units represented by the following formulas (4-1) to (4-4) (hereinafter, also referred to as “structural units (III-1) to (III-4)”) and the like. Is mentioned.

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

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

  [A] When the polymer has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 10 mol% with respect to all the structural units constituting the polymer [A], and is preferably 20 mol%. Mole% is more preferable, 30 mol% is further preferable, and 40 mol% is particularly preferable. The upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, further preferably 65 mol%, and particularly preferably 60 mol%. By setting the content ratio of the structural unit (III) in the above range, the sensitivity of the radiation-sensitive resin composition can be further improved.

  The structural unit (III) is obtained by polymerizing a monomer in which the hydrogen atom of the —OH group of hydroxystyrene is substituted with an acetyl group or the like, and then hydrolyzing the obtained polymer in the presence of a base such as an amine. It can be formed by performing a reaction or the like.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing an alcoholic hydroxyl group. [A] Since the polymer has the structural unit (IV), the solubility in a developer can be more appropriately adjusted, and as a result, the LWR performance and the like of the radiation-sensitive resin composition can be further improved. Can be done. Further, the adhesiveness of the resist pattern to the substrate can be further improved.

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

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

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

  When the polymer [A] has the structural unit (IV), the lower limit of the content ratio of the structural unit (IV) is preferably 10 mol% based on all the structural units constituting the polymer [A], and is preferably 20 mol%. Mole% is more preferable, 30 mol% is further preferable, and 40 mol% is particularly preferable. The upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, further preferably 65 mol%, and particularly preferably 60 mol%. By setting the content of the structural unit (IV) in the above range, the polymer [A] can further appropriately adjust the solubility in a developer, and as a result, the LWR of the radiation-sensitive resin composition can be adjusted. Performance and the like can be further improved. Further, the adhesion of the resist pattern to the substrate can be further improved.

[Other structural units]
[A] The polymer may have other structural units in addition to the structural units (I) to (IV). Examples of the other structural unit include a structural unit containing a ketone carbonyl group, a cyano group, a carboxy group, a nitro group, an amino group or a combination thereof, and a non-dissociable monovalent alicyclic hydrocarbon group ( And a structural unit derived from (meth) acrylic acid ester. The upper limit of the content ratio of the other structural units is preferably 20 mol%, more preferably 10 mol%, based on all the structural units constituting the polymer [A].

  [A] The lower limit of the content of the polymer is preferably 70% by mass, more preferably 80% by mass, and still more preferably 85% by mass, based on the total solid content of the radiation-sensitive resin composition. “Total solids” refers to the sum of components other than the [C] solvent in the radiation-sensitive resin composition. The radiation-sensitive resin composition may contain one or more [A] polymers.

<[A] Method for synthesizing polymer>
[A] The polymer can be synthesized, for example, by polymerizing a monomer giving each structural unit in a suitable solvent using a radical polymerization initiator or the like.

Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis (3-cyclopropyl) Azo radical initiators such as propionitrile), 2,2′-azobis (3,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate;
Peroxide radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide and the like can be mentioned. Of these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is more preferred. These radical polymerization initiators can be used alone or in combination of two or more.

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

  The lower limit of the reaction temperature in the polymerization is preferably 40 ° C, more preferably 50 ° C. The upper limit of the reaction temperature is preferably 150 ° C, more preferably 120 ° C. The lower limit of the reaction time in the polymerization is preferably 1 hour, more preferably 2 hours. The upper limit of the reaction time is preferably 48 hours, and more preferably 24 hours.

  [A] The lower limit of the weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of the polymer is preferably 1,000, more preferably 3,000, still more preferably 4,000, and 000 is particularly preferred. The upper limit of Mw is preferably 50,000, more preferably 30,000, even more preferably 20,000, and particularly preferably 10,000. [A] When the Mw of the polymer is in the above range, the coating property of the radiation-sensitive resin composition is improved and the development defect suppressing property is further improved.

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

<[B] compound>
The compound [B] is a compound having an anion represented by the following formula (1). The compound [B] exerts an effect as an acid diffusion controller which controls a diffusion phenomenon of an acid generated from the following compound [D] in the resist film by the action of radiation and suppresses an undesired chemical reaction in a non-exposed region. The radiation-sensitive resin composition can be excellent in development defect suppressing property, watermark defect suppressing property and storage stability by using the compound [B] as an onium salt compound as an acid diffusion controller. . The compound [B] may be used alone or in combination of two or more.

The formula (1), X, -C (= O) Y, -C (= O) OY, -C (GR X) 2 Y, -C (= O) NYY ', - S (= O) _{2 Y, -S (= O)} 2 OY, -S (= O) 2 NYY ', - C (= O) OC (= O) Y or -C (= O) N (Y ) C (= O) Y '. G is each independently an oxygen atom or a sulfur atom. R ^X is each independently a monovalent organic group having 1 to 20 carbon atoms or 4 to 20 ring members together with -GCCG- in which two R ^x are combined with each other. Of the ring structure. R ¹ , R ² , R ³ , R ⁴ , Y and Y ′ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or Y or Y ′ and R ¹ , Y or Y ′ and R ² , Y or Y ′ and R ^3, or Y or Y ′ and R ⁴ are combined with each other to form a ring structure having 3 to 20 ring members formed together with the carbon atoms to which they are bonded. However, when R ^{1 to} R ⁴ are monovalent organic groups, R ^{1 to} R ⁴ do not contain a fluorine atom. R ^f1 and R ^f2 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms.

The radiation-sensitive resin composition contains a compound [B] in addition to the polymer [A] and the solvent [C], and thus is excellent in development defect suppression and watermark defect suppression. The reason that the radiation-sensitive resin composition has the above-described structure to achieve the above-described effects is not necessarily clear, but can be inferred, for example, as follows. That is, the anion of the compound [B] has two fluorine atoms bonded to the carbon atom to which -COO ^- is bonded, and the hydrophobicity of the radiation-sensitive resin composition as a whole is reduced by the hydrophobicity of the fluorine atom. It is considered that the solubility in a developer can be improved by the electron-withdrawing property while maintaining. As a result, it is considered that the radiation-sensitive resin composition has improved suppression of development defects and suppression of watermark defects. Further, when a conventional onium salt compound is contained as an acid diffusion controller, precipitation of a poorly soluble salt due to a decomposition reaction with the following polymer [E] is inevitable, but according to the compound [B], It is conceivable that the above-mentioned precipitation is suppressed due to a moderately low nucleophilicity due to the structure of the formula (1), and as a result, the storage stability of the radiation-sensitive resin composition is improved.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^X of —C (GR ^X ) ₂ Y include a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a carbon atom of this hydrocarbon group. - group containing a divalent heteroatom containing group at the end of the bond side of the R ^X between atoms or between G-R ^X (g), a portion of the hydrogen atom of the hydrocarbon group and the group (g) is or Examples thereof include groups in which all are substituted with a hetero atom-containing group.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent linear hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a carbon number having 1 to 20 carbon atoms. And 6-20 monovalent aromatic hydrocarbon groups.
Examples of the chain hydrocarbon group include alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group and t-butyl group;
Alkenyl groups such as an ethenyl group, a propenyl group and a butenyl group;
Alkynyl groups such as an ethynyl group, a propynyl group and a butynyl group are exemplified.

Examples of the alicyclic hydrocarbon group include a monovalent monocyclic alicyclic saturated hydrocarbon group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group;
A monovalent monocyclic alicyclic unsaturated hydrocarbon group such as a cyclobutenyl group, a cyclopentenyl group, and a cyclohexenyl group;
A monovalent polycyclic alicyclic saturated hydrocarbon group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, and a tetracyclododecyl group;
Examples thereof include monovalent polycyclic alicyclic unsaturated hydrocarbons such as a norbornenyl group, a tricyclodecenyl group, and a tetracyclododecenyl group.

Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group and an anthryl group;
And aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group and naphthylmethyl group.

  Examples of the hetero atom contained in the hetero atom-containing group include a halogen atom such as a chlorine atom and a bromine atom, an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom and a phosphorus atom. Of these, an oxygen atom and a sulfur atom are preferred.

Examples of the divalent hetero atom-containing group contained in the end of the bond side of the R ^X between atoms or between G-R ^X, for example, -C (= O) - - the carbon of the hydrocarbon group, - O-, —S—, —C (＝ S) —, and a combination thereof. When these divalent hetero atom-containing groups contain carbon atoms, the total number of carbon atoms of R ^x is 1 to 20, including those contained in these divalent hetero atom-containing groups.

  Examples of the hetero atom-containing group which is substituted for part or all of the hydrogen atoms of the hydrocarbon group and the group (g) include, for example, an oxo group (基 O), a thioxo group (＝ S), a hydroxy group, a carboxy group , A sulfanyl group (-SH) and the like.

Examples of the ring structure having 4 to 20 ring members which are formed together with -GCCG- in which the two ^Rx 's are combined and bonded to each other include, for example, a cyclic acetal ring such as 1,3-dioxacyclopentane ( (Including a cyclic ketal ring), a structure having a ring containing a group represented by -OCS- such as 1-thia-3-oxacyclopentane, and a structure having a ring including 1,3-dithiacyclopentane and the like. And a structure having a ring containing a group represented by -S-C-S-.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ¹ , R ² , R ³ , R ⁴ , Y and Y ′ include a monovalent hydrocarbon group having 1 to 20 carbon atoms, A group (g) containing a divalent heteroatom-containing group at the carbon-carbon or at the terminal of the bond side of the hydrocarbon group, and part or all of the hydrogen atoms of the hydrocarbon group and the group (g) are heteroatoms And a group substituted with a contained group.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include the same groups as those described above for R ^X.

  Examples of the hetero atom contained in the hetero atom-containing group include a halogen atom such as a chlorine atom and a bromine atom, an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom and a phosphorus atom. Among these, an oxygen atom, a sulfur atom and a nitrogen atom are preferred.

Examples of the divalent hetero atom-containing group contained between carbon-carbon or at the terminal on the bond side include, for example, -C (= O)-, -O-, -NR'-, -S-, -C (= S)-and groups obtained by combining these. R ′ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. When these divalent hetero atom-containing groups contain carbon atoms, the total number of carbon atoms of the above R ¹ , R ² , R ³ , R ⁴ , Y and Y ′ is the same as that of these divalent hetero atom-containing groups. It is 1 to 20 including those included.

  Examples of the hetero atom-containing group which is substituted for part or all of the hydrogen atoms of the hydrocarbon group and the group (g) include, for example, an oxo group (基 O), a thioxo group (＝ S), a hydroxy group, a carboxy group , A sulfanyl group (-SH), an amino group, a cyano group, a halogen atom and the like.

Y or Y 'and R ¹ , Y or Y' and R ² , Y or Y 'and R ^3, or Y or Y' and R ⁴ are combined with each other and have 3 to 20 ring members formed together with the carbon atom to which they are bonded. Examples of the ring structure include an alicyclic structure such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a norbornane structure, and an adamantane structure;
Examples include aliphatic heterocyclic structures such as an oxacyclopentane structure, a thiacyclopentane structure, and an azacyclopentane structure.

  The ring structure may be in any form such as a single ring, multiple rings, condensed ring, bridged structure and the like. Further, the ring structure may have a substituent.

Y or Y ′ and R ¹ , Y or Y ′ and R ² , Y or Y ′ and R ^3, or Y or Y ′ and R ⁴ combined with each other and having 3 to 20 carbon atoms formed together with the carbon atom to which they are bonded. Examples of the ring structure include a ring structure represented by the following formula.

  As the ring structure, among these, a ring structure represented by the above formula (bb-1), a ring structure represented by the above formula (bb-5) and the like are preferable.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms represented by R ^f1 and R ^f2 include a fluorinated alkyl group having 1 to 4 carbon atoms. As the monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms represented by R ^f1 and R ^f2 , a perfluoroalkyl group is more preferred, and a trifluoromethyl group is still more preferred.

As the X, from the viewpoint of enhancing the storage stability and developing defect suppression of the radiation-sensitive resin composition, -C (= O) Y, -C (= O) OY, -C (OR X) 2 _{Y, -S (= O) 2} Y, -S (= O) 2 OY, -S (= O) 2 NYY ', - C (= O) OC (= O) Y or -C (= O) N (Y) C (＝ O) Y ′, wherein R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, or Y or Y ′ and R ¹ , Y or Y ′ and R ² , Y or Y 'and R ³ or Y or Y' and R ⁴ represent an alicyclic structure or an aliphatic heterocyclic structure having 3 to 20 ring members which are combined with each other and formed together with a carbon atom to which they are bonded. Is more preferred.

R ¹ , R ² , R ³ and R ⁴ are more preferably hydrogen atoms from the viewpoint of further improving the storage stability and development defect suppression of the radiation-sensitive resin composition.

R ^f1 and R ^f2 are more preferably fluorine atoms from the viewpoint of further improving the storage stability and development defect suppression of the radiation-sensitive resin composition.

  [B] The compound is not particularly limited as long as it contains an anion represented by the following formula (1), and examples thereof include a compound formed by a combination of an anion represented by the following formula (2) and a cation. .

In the formula (2), X, R ^X , R ¹ , R ² , R ³ , R ⁴ , Y, Y ′, R ^f1 and R ^f2 have the same ^{meanings as} in the formula (1). Z ⁺ is a monovalent cation.

Examples of the monovalent cation represented by Z ⁺ include cations containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. No. Examples of the cation containing S (sulfur) as an element include a sulfonium cation and a tetrahydrothiophenium cation, and examples of the cation containing I (iodine) as an element include an iodonium cation.

  Examples of the sulfonium cation include a cation represented by the following formula (Q-1). Examples of the tetrahydrothiophenium cation include a cation represented by the following formula (Q-2). Examples of the iodonium cation include a cation represented by the following formula (Q-3).

In the above formula (Q-1), R ^c1 , R ^c2 and R ^c3 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkyl group. An aromatic hydrocarbon group having 6 to 12 carbon atoms, —OSO ₂ —RP ^′ or —SO ₂ —RQ ^′ , or a ring structure in which two or more of these groups are combined with each other Represents R ^{P ′} and R ^{Q ′} each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic carbon group having 5 to 25 carbon atoms. It is a hydrogen group 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. When each of R ^{c1 to} R ^{c3 and} R ^{P ′} and R ^{Q ′} is plural, the plural R ^{c1 to} R ^{c3 and} R ^{P ′} and R ^{Q ′} may be the same or different.
In the formula (Q-2), R ^d1 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. Group. k4 is an integer of 0 to 7. If R ^d1 is plural, the plurality of R ^d1 may be the same or different, and a plurality of R ^d1 may represent a constructed ring aligned with each other. R ^d2 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 to 6. If R ^d2 is a multiple, the plurality of R ^d2 may be the same or different, a plurality of R ^d2 may represent configured ring aligned with each other. t is an integer of 0 to 3.
In the formula (Q-3), R ^e1 and R ^e2 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted carbon group having 6 carbon atoms. 12 aromatic hydrocarbon group, or an -OSO ₂ -R ^R or _-SO 2 -R ^S, or two or more are combined with each other configured ring of these groups. R ^R and R ^S are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, 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. When each of R ^e1 , R ^e2 , R ^R, and R ^S is plural, the plurality of R ^e1 , R ^e2 , R ^R, and R ^S may be the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^{c1 to} R ^c3 , R ^d1 , R ^d2 , R ^e1 and R ^e2 include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. And the like.
Examples of the unsubstituted branched alkyl group represented by R ^{c1 to} R ^c3 , R ^d1 , R ^d2 , R ^e1 and R ^e2 include, for example, i-propyl, i-butyl, sec-butyl, t -Butyl group and the like.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^{c1 to} R ^c3 , R ^e1 and R ^e2 include an aryl group such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group; a benzyl group; And aralkyl groups such as phenethyl groups.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^d1 and R ^d2 include a phenyl group, a tolyl group, and a benzyl group.

Examples of the substituent which may substitute a hydrogen atom contained in 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, and a cyano group. Nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group and the like.
Among these, a halogen atom is preferred, and a fluorine atom is more preferred.

As the above R ^{c1 to} R ^c3 , R ^d1 , R ^d2 , R ^e1 and R ^e2 , unsubstituted linear or branched alkyl groups, fluorinated alkyl groups, unsubstituted monovalent aromatic hydrocarbon groups , —OSO ₂ —R ^** , and —SO ₂ —R ^** are preferred, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferred, and a fluorinated alkyl group is even more preferred. R ^** is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As k1, k2, and k3 in the above formula (Q-1), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable.
K4 in the above formula (Q-2) is preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 1. k5 is preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0.
K6 and k7 in the above formula (Q-3) are preferably integers of 0 to 2, more preferably 0 or 1, and still more preferably 0.

  Examples of the sulfonium cation include cations represented by the following formulas (i-1) to (i-21).

  Among these, a cation represented by the above formula (i-1) and a cation represented by the above formula (i-21) are preferable.

  Examples of the tetrahydrothiophenium cation include cations represented by the following formulas (i'-1) to (i'-4).

  Among these, the cation represented by the above formula (i'-2) is preferable.

  Examples of the iodonium cation include cations represented by the following formulas (ii-1) to (ii-25).

  Among these, a cation represented by the above formula (ii-11) is preferable.

  Examples of the compound [B] include compounds represented by the following formulas (B-1) to (B-17) (hereinafter, also referred to as “compounds (B-1) to (B-17)”). Can be

  [B] As the compound, among these, compounds (B-1) to (B-8) are preferable, and compound (B-6) is more preferable.

  The method for producing the compound [B], which is an acid diffusion controller, is represented by the following formula (c) by, for example, reacting a compound represented by the following formula (a) with a compound represented by the following formula (b). A step of obtaining a compound represented by the following formula (d), a step of obtaining a compound represented by the following formula (d) by hydrolysis of an ester group of the compound represented by the following formula (c), And reacting the compound with a salt represented by the following formula (e) to obtain a compound represented by the following formula (1 ′).

[B] As the compound, in the above formula (2), R ² is a hydrogen atom, and Y or Y ′ and R ¹ , Y or Y ′ and R ^3, or Y or Y ′ and R ⁴ have a ring structure. The following compound (1 ′) when not formed can be synthesized, for example, according to the following reaction scheme. According to the above method, the compound [B] can be synthesized simply and with high yield. The compound [B] other than these can also be synthesized using a known method.

The formula (a) ~ (e) and in (1 '), X is, -C (= O) Y, -C (= O) OY, -C (GR X) 2 Y, -C (= O) _{NYY ', - S (= O} ) 2 Y, -S (= O) 2 OY, -S (= O) 2 NYY', - C (= O) OC (= O) Y or -C (= O) N (Y) C (= O) Y '.
G is each independently an oxygen atom or a sulfur atom.
R ^X is each independently a monovalent organic group having 1 to 20 carbon atoms or 4 to 20 ring members together with -GCCG- in which two R ^x are combined with each other. Of the ring structure.
R ¹ ′, R ³ ′, R ⁴ ′, Y and Y ′ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or Y or Y ′ and R ¹ ′ , Y or Y ′ and R ³ ′ or Y or Y ′ and R ⁴ ′ together form a ring structure having 3 to 20 ring members which is formed together with the carbon atom to which they are bonded. However, when R ¹ ′, R ³ ′, and R ⁴ ′ are monovalent organic groups, R ¹ ′, R ³ ′, and R ⁴ ′ do not include a fluorine atom.
R ⁶ is a monovalent hydrocarbon group having 1 to 20 carbon atoms.
R ^f1 and R ^f2 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms.
Q is a chlorine, bromine or iodine atom.
Z ⁺ is a monovalent cation.
M ^- is a monovalent anion.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ¹ ′, R ³ ′ and R ⁴ ′ are the same as those described above for R ¹ , R ² , R ³ , R ⁴ , Y and Y ′. The same groups as the groups can be mentioned.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ⁶ include the same groups as those described above for R ^A2 , R ^A3, and R ^A4 .

  The lower limit of the content of the compound [B] is preferably 0.1 part by mass, more preferably 0.5 part by mass, and still more preferably 1 part by mass with respect to 100 parts by mass of the polymer [A]. The upper limit of the content of the compound [B] is preferably 25 parts by mass, more preferably 20 parts by mass, still more preferably 15 parts by mass, and particularly preferably 10 parts by mass with respect to 100 parts by mass of the polymer [A]. . When the content of the compound (B) is less than the above lower limit, lithography performance such as resolution of the radiation-sensitive resin composition may be reduced. When the content of the compound (B) exceeds the above upper limit, the sensitivity of the radiation-sensitive resin composition may decrease.

<[C] solvent>
The radiation-sensitive resin composition usually contains a solvent [C]. [C] The solvent is not particularly limited as long as it can dissolve or disperse at least the [B] compound, the [E] polymer, and the [D] compound contained as necessary.

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

As the alcohol solvent, for example,
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 polyhydric alcohol solvent having 2 to 18 carbon atoms such as 1,2-propylene glycol;
Examples thereof include polyhydric alcohol partial ether solvents having 3 to 19 carbon atoms, such as propylene glycol monomethyl ether.

Examples of the ether solvent include, for example,
Dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, diheptyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
Aromatic ring-containing ether solvents such as diphenyl ether and anisole (methylphenyl ether) are exemplified.

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 (methyl-n-pentyl ketone), and ethyl-n-butyl ketone. , Methyl-n-hexyl ketone, di-iso-butyl ketone, chain ketone solvents such as trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
Examples thereof include 2,4-pentanedione, acetonylacetone, and acetophenone.

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

As the ester solvent, for example,
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;
lactone solvents such as γ-butyrolactone and δ-valerolactone;
Polyvalent carboxylic acid diester solvents such as diethyl oxalate;
Examples thereof include carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate.

As the hydrocarbon solvent, for example,
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 them, the [C] solvent is preferably an ester solvent or a ketone solvent, more preferably a polyhydric alcohol partial ether carboxylate solvent, a lactone solvent or a cyclic ketone solvent, and more preferably a polyhydric alcohol partial alkyl ether. Acetate, lactone solvents and cyclic ketone solvents are more preferred, and propylene glycol monomethyl ether acetate, γ-butyrolactone and cyclohexanone are particularly preferred. The radiation-sensitive resin composition may contain one or more [C] solvents.

<[D] compound>
[D] The compound is a substance that generates sulfonic acid by the action of radiation. The generated sulfonic acid dissociates the acid-dissociable groups of the [E] polymer, [A] polymer and the like to generate carboxy groups and the like, and changes the solubility of these polymers in a developing solution. A resist pattern can be formed from the radiation-sensitive resin composition.

  Examples of the compound [D] include an onium salt compound, an N-sulfonyloxyimide compound, a halogen-containing compound, and a diazoketone compound.

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

  Specific examples of the compound [D] include, for example, compounds described in paragraphs [0080] to [0113] of JP-A-2009-134088.

  As the compound [D], a compound represented by the following formula (vi) is preferable. By making the compound [D] a compound represented by the following formula (vi), an acid generated by the action of radiation due to interaction with the polar structure of the polymer [E] or [A], or the like. It is considered that the diffusion length in the resist film is more appropriately reduced, and as a result, the lithography performance of the radiation-sensitive resin composition can be further improved.

In the above formula (vi), R ^b1 is a monovalent group containing an alicyclic structure having 6 or more ring members or a monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members. R ^b2 is a fluorinated alkanediyl group having 1 to 10 carbon atoms. T ⁺ is a monovalent radiolytic onium cation.

The “number of ring members” in the above R ^b1 refers to the number of atoms constituting a ring having an alicyclic structure and an aliphatic heterocyclic structure, and in the case of a polycyclic alicyclic structure and a polycyclic aliphatic heterocyclic structure, Refers to the number of atoms constituting a polycyclic ring.

Examples of the monovalent group containing an alicyclic structure having 6 or more ring members represented by R ^b1 include a monovalent monocyclic alicyclic saturated group such as a cyclooctyl group, a cyclononyl group, a cyclodecyl group, and a cyclododecyl group. Hydrocarbon group;
A monovalent monocyclic alicyclic unsaturated hydrocarbon group such as a cyclooctenyl group and a cyclodecenyl group;
A monovalent polycyclic alicyclic saturated hydrocarbon group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, and a tetracyclododecyl group;
Examples include a monovalent polycyclic alicyclic unsaturated hydrocarbon group such as a norbornenyl group and a tricyclodecenyl group.

Examples of the monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members represented by R ^b1 include a group containing a lactone structure such as a norbornane lactone-yl group;
A group containing a sultone structure such as a norbornane sultone-yl group;
An oxygen atom-containing heterocyclic group such as an oxacycloheptyl group or an oxanorbornyl group;
A nitrogen-containing heterocyclic group such as an azacyclohexyl group, an azacycloheptyl group, a diazabicyclooctane-yl group;
Examples thereof include a sulfur atom-containing heterocyclic group such as a thiacycloheptyl group and a thiannorbornyl group.

The number of ring members of the group represented by R ^b1 is preferably 8 or more, more preferably 9 to 15, and still more preferably 10 to 13, from the viewpoint that the above-mentioned acid diffusion length becomes more appropriate.

As the above R ^b1 , among these, a monovalent group containing an alicyclic structure having 9 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members are preferable, and an adamantyl group and a hydroxyadamantyl are preferable. Group, norbornane lactone-yl group and 5-oxo-4-oxatricyclo [4.3.1.1 ^3,8 ] undecane-yl group are more preferred, and an adamantyl group is still more preferred.

Examples of the fluorinated alkanediyl group having 1 to 10 carbon atoms represented by R ^b2 include at least one hydrogen atom of an alkanediyl group having 1 to 10 carbon atoms such as a methanediyl group, an ethanediyl group, and a propanediyl group. With a fluorine atom.
Among these, SO ₃ ^- fluorinated alkane diyl group which has a fluorine atom to carbon atom is bonded to adjacent groups are preferred, SO ₃ ^- 2 fluorine atoms to the carbon atom adjacent to the group is attached Fluorinated alkanediyl groups are more preferred, 1,1-difluoromethanediyl group, 1,1-difluoroethanediyl group, 1,1,3,3,3-pentafluoro-1,2-propanediyl group, 1,1 And 2,2,2-tetrafluoroethanediyl, 1,1,2,2-tetrafluorobutanediyl and 1,1,2,2-tetrafluorohexanediyl are more preferred.

Examples of the monovalent radiolytic onium cation represented by T ⁺ include those similar to the onium cation exemplified as Z ⁺ in the formula (2) of the compound [B].

  Examples of the compound [D] include compounds represented by the following formulas (vi-1) to (vi-17) (hereinafter, also referred to as “compounds (vi-1) to (vi-17)”). Can be

  [D] As the compound, an onium salt compound is preferable, and a sulfonium salt is more preferable, and compounds (vi-1) to (vi-3) and compounds (vi-13) to (vi-17) are preferable. More preferred.

  The lower limit of the content of the compound [D] is preferably 0.1 part by mass, more preferably 0.5 part by mass, still more preferably 1 part by mass, and more preferably 3 parts by mass based on 100 parts by mass of the polymer [A]. Parts are particularly preferred. The upper limit of the compound [D] is preferably 40 parts by mass, more preferably 30 parts by mass, and still more preferably 25 parts by mass, based on 100 parts by mass of the polymer [A]. [D] The compound may be used alone or in combination of two or more.

<[E] polymer>
[E] The polymer is a polymer containing a fluorine atom. [E] The polymer preferably has at least one of the following structural units (V) and (VI). Since the radiation-sensitive resin composition contains the polymer [E], when the resist film is formed, the distribution is unevenly distributed on the surface of the resist film due to the oil-repellent characteristic of the polymer [E]. This tends to prevent the compound [D] and the acid diffusion controller from being eluted into the immersion liquid during the immersion exposure. Further, due to the water-repellent characteristic of the polymer [E], the advancing contact angle between the resist film and the immersion liquid can be controlled within a desired range, and the occurrence of bubble defects can be suppressed. Further, the receding contact angle between the resist film and the immersion liquid is increased, and high-speed scanning exposure can be performed without leaving water droplets. Also, in electron beam exposure or EUV exposure, the water repellency of the polymer [E] can improve the defect suppression of the resist film. When the radiation-sensitive resin composition contains the polymer [E], a resist film suitable for immersion exposure, electron beam exposure, EUV exposure, or the like can be formed.

  [E] The polymer preferably has a larger total mass content of fluorine atoms than the [A] polymer in the radiation-sensitive resin composition. [E] The polymer has a greater total mass content of fluorine atoms than the polymer [A], so that the degree of uneven distribution described above is higher, and the resulting resist film surface has water repellency and elution suppression properties. The characteristics can be further improved.

[E] The lower limit of the mass content of fluorine atoms in the polymer is preferably 1% by mass, more preferably 2% by mass, still more preferably 4% by mass, and particularly preferably 7% by mass. As a maximum of the above-mentioned total mass content, 60 mass% is preferred, 40 mass% is more preferred, and 30 mass% is still more preferred. The mass content of fluorine atoms in the polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR spectrum measurement or the like.

  [E] The polymer preferably has an alkali-dissociable group. [E] When the polymer has an alkali-dissociable group, the surface of the resist film can be effectively changed from hydrophobic to hydrophilic during alkali development, and the radiation-sensitive resin composition is improved in suppressing development defects. . [E] When the polymer has an alkali-dissociable group, ion exchange with a conventionally used onium salt compound is likely to occur, and the storage stability and development defect suppression of the radiation-sensitive resin composition are further reduced. . However, since the radiation-sensitive resin composition uses the above-mentioned specific compound [B] as an onium salt compound, even when the polymer [E] has an alkali-dissociable group, it has poor storage stability and development defect suppression properties. It can be excellent. The “alkali-dissociable group” is a group that substitutes for a hydrogen atom of a carboxy group, a hydroxy group, or the like, and dissociates in an alkaline aqueous solution (eg, a 2.38% by mass tetramethylammonium hydroxide aqueous solution at 23 ° C.). Group.

  [E] The form in which the fluorine atom is contained in the polymer is not particularly limited, and may be any of those bonded to the main chain, the side chain, and the terminal. However, the structural unit containing a fluorine atom (hereinafter referred to as “structural unit (V)”) ). [E] The polymer may contain an acid-dissociable group in addition to at least one of the structural unit (V) and the structural unit (VI), from the viewpoint of improving development defect suppression of the radiation-sensitive resin composition. It is preferable to have a structural unit (Structural unit (I) in the polymer [A] described later).

[Structural unit (V)]
The structural unit (V) is a structural unit represented by the following formula (5) (hereinafter, also referred to as “structural unit (V-1)”). [E] The polymer can adjust the fluorine atom content by having the structural unit (V).

In the above formula (5), R ⁵¹ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxyalkyl group having 2 to 10 carbon atoms. W is a divalent organic group having 1 to 20 carbon atoms. R ⁵² 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 W and R ⁵² is a group containing a fluorine atom.

Examples of the alkyl group having 1 to 10 carbon atoms represented by ^{R 51,} a methyl group, an ethyl group, n- propyl group, and n- butyl.

As the alkoxyalkyl group having 2 to 10 carbon atoms represented by R ^51, such as methoxymethyl group, methoxyethyl group, methoxypropyl group, methoxybutyl group, ethoxymethyl group, ethoxyethyl, ethoxypropyl, ethoxybutyl And the like.

As the divalent organic group having 1 to 20 carbon atoms represented by W, for example, one hydrogen atom is selected from the monovalent organic group having 1 to 20 carbon atoms exemplified as R ^{15 in the} above formula (4). Excluded groups and the like.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ⁵² include a monovalent linear hydrocarbon group having 1 to 20 carbon atoms and a monovalent alicyclic group having 3 to 20 carbon atoms. Examples thereof include a hydrocarbon group and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include an alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an i-propyl group;
Alkenyl groups such as an ethenyl group, a propenyl group and a butenyl group;
Alkynyl groups such as an ethynyl group, a propynyl group and a butynyl group are exemplified.

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

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

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^52, chain hydrocarbon group and alicyclic hydrocarbon group is preferred.

The monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^52, for example, and the like fluorinated alkyl group having 1 to 20 carbon atoms is. As the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ⁵² , a fluorine atom and a fluorinated alkyl group are preferable, a fluorine atom and a perfluoroalkyl group are more preferable, and a fluorine atom and trifluoro Methyl groups are more preferred.

From the viewpoint of further improving the effect as an alkali-dissociable group, at least one of W and R ⁵² is preferably a group containing a fluorine atom.

  When the polymer [E] has the structural unit (V), the upper limit of the content ratio of the structural unit (V) is preferably 100 mol%, and more preferably 95 mol% based on all the structural units in the polymer [E]. Is more preferable, and 90 mol% is further preferable. With such a content ratio, the fluorine atom content of the polymer [E] can be more appropriately adjusted.

[Structural unit (VI)]
The structural unit (VI) is a structural unit represented by the following formula (6) (hereinafter, also referred to as “structural unit (VI)”). [E] The polymer can control the fluorine atom content by having the structural unit (VI).

In the above formula (6), ^Rh is a hydrogen atom, a methyl group or a trifluoromethyl group. G represents a single bond, an oxygen atom, a sulfur _{atom, -CO-O -, - SO} 2 -NH -, - is CO-NH- or -O-CO-NH-. R ^k 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.

As the R ^h, from the viewpoint of copolymerizability and the like of the monomer giving the structural unit (VI), preferably a hydrogen atom or a methyl group, more preferably a methyl group.

As the _{G, -CO-O -, -} SO 2 -NH -, - CO-NH- or -O-CO-NH- are preferred, -CO-O-are more preferred.

Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by R ^k include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, , 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 Groups, 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 monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^k include a monofluorocyclopentyl group, a difluorocyclopentyl group, a perfluorocyclopentyl group, a monofluorocyclohexyl group, and a difluorocyclopentyl group. , Perfluorocyclohexylmethyl group, fluoronorbornyl group, fluoroadamantyl group, fluorobornyl group, fluoroisobornyl group, fluorotricyclodecyl group, fluorotetracyclodecyl group and the like.

As the above R ^k , among these, a fluorinated chain hydrocarbon group is preferable, and a 2,2,2-trifluoroethyl group, 1,1,1,3,3,3-hexafluoro-2-propyl is preferred. Groups are more preferred, and 1,1,1,3,3,3-hexafluoro-2-propyl groups are even more preferred.

  When the polymer [E] has the structural unit (VI), the upper limit of the content ratio of the structural unit (VI) is preferably 100 mol%, more preferably 95 mol%, based on all the structural units in the polymer [E]. Is more preferable, and 90 mol% is further preferable. With such a content ratio, the fluorine atom content of the polymer [E] can be more appropriately adjusted.

  The lower limit of the content of the polymer [E] is preferably 0.1 part by mass, more preferably 0.2 part by mass, and more preferably 0.5 part by mass with respect to 100 parts by mass of the polymer [A] described below. More preferably, 1 part by mass is particularly preferred. [E] The upper limit of the content of the polymer is preferably 30 parts by mass, more preferably 20 parts by mass, still more preferably 15 parts by mass, particularly preferably 10 parts by mass, based on 100 parts by mass of the polymer [A]. preferable.

<[E] Polymer synthesis method>
[E] The polymer can be synthesized, for example, by polymerizing a monomer giving each structural unit in a suitable solvent using a radical polymerization initiator or the like.

  Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis (3-cyclopropylprothyl). Azo radical initiators such as pionitrile), 2,2′-azobis (3,4-dimethylvaleronitrile) and dimethyl 2,2′-azobisisobutyrate; benzoyl peroxide, t-butyl hydroperoxide, 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 in the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Alicyclic saturated hydrocarbons such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, and chlorobenzene;
Saturated carboxylic 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 and 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes and diethoxyethanes;
Examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. The solvents used for these polymerizations may be used alone or in combination of two or more.

  The reaction temperature in the above polymerization is usually preferably 40 ° C to 150 ° C, and 50 ° C to 120 ° C. The reaction time is usually preferably 1 hour to 48 hours, and 1 hour to 24 hours.

  [E] The weight average molecular weight (Mw) of the polymer in terms of polystyrene measured by gel permeation chromatography (GPC) is not particularly limited, but is preferably from 1,000 to 50,000, more preferably from 2,000 to 30,000. It is more preferably 2,500 or more and 20,000 or less, particularly preferably 3,000 or more and 15,000 or less. [E] By setting the Mw of the polymer in the above range, the coating property and the development defect suppressing property of the radiation-sensitive resin composition are improved. [E] If the Mw of the polymer is less than the above lower limit, a resist film having sufficient heat resistance may not be obtained. [E] When the Mw of the polymer exceeds the above upper limit, the developability of the resist film may decrease.

  [E] The ratio (Mw / Mn) of Mw to polystyrene-equivalent number average molecular weight (Mn) by gel permeation chromatography (GPC) of the polymer is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, One or more and two or less are more preferable.

<Other optional components>
The radiation-sensitive resin composition may contain other optional components other than the components [A] to [E]. Examples of the other optional components include an acid diffusion controller other than the compound [B], a surfactant, an alicyclic skeleton-containing compound, and a sensitizer. These other optional components may be used alone or in combination of two or more.

[Other acid diffusion controllers]
The radiation-sensitive resin composition may contain an acid diffusion controller other than the compound [B] as long as the effects of the present invention are not impaired. Another acid diffusion controller controls the diffusion phenomenon of an acid generated from the compound [D] in the resist film by the action of radiation. As a result, an effect of suppressing an undesired chemical reaction in the non-exposed area is exhibited. Further, the storage stability of the obtained radiation-sensitive resin composition is further improved. In addition, the resolution as a resist is further improved, and a line width change of a resist pattern due to a change in a withdrawal time from exposure to development processing can be suppressed, and a radiation-sensitive resin composition having excellent process stability can be obtained. . As the content form of the other acid diffusion controller in the radiation-sensitive resin composition, even in the form of a free compound (hereinafter, appropriately referred to as “another acid diffusion controller”), it is incorporated as a part of the polymer. Or both of these forms.

  As other acid diffusion controlling agents, for example, a compound represented by the following formula (vii) (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 (III)), a compound having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compound (IV)"), an amide group-containing compound, a urea compound, a nitrogen-containing heterocyclic compound and the like. .

In the above formula (vii), R ^f4 , R ^f5 and R ^f6 are each independently a hydrogen atom, an ^optionally substituted linear, branched or cyclic alkyl group, aryl group or aralkyl group. .

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

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

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

  Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methylpyrrolidone. Can be

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

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

  Further, as the nitrogen-containing organic compound, a compound having an acid-dissociable group can also be used. Examples of such nitrogen-containing organic compounds having an acid-dissociable group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, and 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 another acid diffusion controller, a photo-degradable base that generates a weak acid by the action of radiation can be used. Examples of the photodisintegrable base include an onium salt compound which is decomposed by the action of radiation and loses its acid diffusion controllability (excluding those corresponding to the compound [B]).

  When the other acid diffusion controller is another acid diffusion controller, the content of the other acid diffusion controller is 0 to 20 parts by mass relative to 100 parts by mass of the polymer (A). Preferably, 0.1 to 15 parts by mass is more preferable, 0.3 to 10 parts by mass is more preferable, and 0.5 to 5 parts by mass is particularly preferable. If the content of the other acid diffusion controller exceeds the above upper limit, the sensitivity of the radiation-sensitive resin composition may decrease.

[Surfactant]
Surfactants have the effect of improving coatability, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol dilaurate. Nonionic surfactants such as stearate; commercially available products include “KP341” manufactured by Shin-Etsu Chemical Co., Ltd., “Polyflow No. 75” and “No. 95” manufactured by Kyoeisha Chemical Co., Ltd., and “Ftop” manufactured by Tochem Products. EF301, EF303, EF352, DIC's MegaFac F171, FDIC 173, Sumitomo 3M's Florard FC430, FC431, Asahi Glass Industry's Asahi Guard AG71 "," Surflon S-382 "," SC-101 "," SC-102 "," SC-103 "," SC-104 "," SC-105 "," SC-106 " And the like. The content of the surfactant in the radiation-sensitive resin composition is usually 2 parts by mass or less based on 100 parts by mass of the polymer [A].

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

[Sensitizer]
The sensitizer has an effect of increasing the amount of acid generated from the compound [D], and has an effect of improving the “apparent sensitivity” of the radiation-sensitive resin composition.

  Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, and phenothiazines. These sensitizers may be used alone or in combination of two or more. The content of the sensitizer in the radiation-sensitive resin composition is usually 2 parts by mass or less based on 100 parts by mass of the polymer [A].

<Method for producing radiation-sensitive resin composition>
The method for producing the radiation-sensitive resin composition includes, for example, a method of preparing a polymer [A], a compound [B], a solvent [C], a compound [D], and a polymer [E] contained as necessary. A step of mixing at a ratio. After mixing, the radiation-sensitive resin composition is preferably filtered, for example, with a filter having a pore size of about 0.2 μm. The total solid content of the radiation-sensitive resin composition is generally 0.1% by mass to 50% by mass, preferably 0.5% by mass to 30% by mass, and more preferably 1% by mass to 20% by mass. .

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

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

[Coating process]
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 a silicon wafer and a wafer coated with aluminum. A resist film is formed by applying the radiation-sensitive resin composition on the substrate. The method of applying the radiation-sensitive resin composition is not particularly limited, but it can be applied by a known method such as a spin coating method. When applying the radiation-sensitive resin composition, the amount of the radiation-sensitive resin composition to be applied is adjusted so that the formed resist film has a desired film thickness. After applying the radiation-sensitive resin composition on a substrate, soft baking (hereinafter, also referred to as “SB”) may be performed to volatilize the solvent. The temperature of the soft bake is usually 30C to 200C, and preferably 50C to 150C.

[Exposure process]
In this step, the resist film obtained in the above coating step is exposed. This exposure is performed by immersion exposure in which radiation is irradiated through an immersion medium such as water and a mask having a predetermined pattern in some cases.

  In the case of immersion exposure, the immersion medium is placed on the resist film, and the resist film is irradiated with radiation through the immersion medium. As the immersion medium, a liquid having a higher refractive index than air is usually used. Specific examples include pure water, long-chain or cyclic aliphatic compounds, and the like. In a state where the immersion medium is interposed, that is, in a state where the immersion medium is filled between the lens and the resist film, radiation is irradiated from an exposure apparatus to expose the resist film through a mask having a predetermined pattern. .

  Examples of the radiation include visible light, ultraviolet light, far ultraviolet light, vacuum ultraviolet light (extreme ultraviolet light (EUV); wavelength of 13.5 nm), electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as electron beams and α-rays. No. In the case of immersion exposure, far ultraviolet rays represented by ArF excimer laser light (wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm) are preferable, and ArF excimer laser light (wavelength 193 nm) is more preferable.

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

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

[Development step]
In this step, the resist film exposed in the exposure step is developed. Thereby, a resist pattern is formed.

  Examples of the developer used for the development include alkali developers such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n. -Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1.5 An alkaline aqueous solution in which at least one alkaline compound such as -diazabicyclo- [4.3.0] -5-nonene is dissolved is preferable. In addition, an appropriate amount of a water-soluble organic solvent such as alcohols such as methanol and ethanol, and a surfactant can be added to the developer.

  Further, as the developer, a developer containing an organic solvent can be used. Examples of the organic solvent include one or more of the organic solvents exemplified as the solvent [C] of the radiation-sensitive resin composition.

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

[Weight average molecular weight (Mw), number average molecular weight (Mn) and degree of dispersion (Mw / Mn)]
The Mw and Mn of the polymer were determined by gel permeation chromatography (GPC) using GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation under the following conditions. It was measured. The degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

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

[ ¹³ C-NMR analysis]
The ¹³ C-NMR analysis for obtaining the content ratio of each structural unit of the polymer was performed using a nuclear magnetic resonance apparatus (“JNM-ECX400” of JEOL Ltd.) and using heavy chloroform as a measurement solvent.

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

  In the above compounds, (M-1) to (M-7) and (M-16) represent the structural unit (I) as (M-8) to (M-9) and (M-11) to (M-11). (M-14) represents the structural unit (II), (M-15) represents the structural unit (III), (M-10) represents the structural unit (IV), and (M-17) represents the structural unit (VI). And compound (M-18) each give a structural unit (V).

[Synthesis Example 1] (Synthesis of polymer (A-1))
As shown in Table 1 below, 9.38 g (50 mol%) of the compound (M-1) and 10.62 g (50 mol%) of the compound (M-8) were dissolved in 40 g of 2-butanone, and the polymerization initiator was further dissolved. Was dissolved in 0.785 g of azobisisobutyronitrile (5 mol% based on all monomers) to prepare a monomer solution. Next, a 200 mL three-necked flask containing 20 g of 2-butanone was heated to 80 ° C. while stirring under a nitrogen atmosphere, and the prepared monomer solution was added dropwise over 3 hours. After completion of the dropwise addition, the polymerization reaction was carried out by heating at 80 ° C. for 3 hours. After the completion of the polymerization reaction, the reaction solution was cooled to room temperature, poured into 300 g of methanol, and the precipitated solid was separated by filtration. The solid separated by filtration was washed twice with 60 mL of methanol, filtered, and then dried under reduced pressure at 50 ° C. for 15 hours to synthesize a polymer (A-1) (yield: 15.8 g, 78.9). %). Mw of the polymer (A-1) was 6,100, and Mw / Mn was 1.41. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from the compound (M-1) and the compound (M-8) were 49.8 mol% and 50.2 mol%, respectively.

[Synthesis Examples 2 to 7] (Synthesis of Polymers (A-2) to (A-7))
Polymers (A-2) to (A-7) shown in Table 1 below were obtained by performing the same operations as in Synthesis Example 1 except for using the types and amounts of monomers shown in Table 1 below. Synthesized.

[Synthesis Example 8] (Synthesis of polymer (A-8))
As shown in Table 1 below, compound (M-1) 54.76 g (50 mol%), compound (M-15) 45.24 g (50 mol%), and azobisisobutyronitrile 4. After dissolving 58 g (5 mol% based on all monomers) and 1,14 g of t-dodecyl mercaptan in 100 g of propylene glycol monomethyl ether, the reaction temperature is kept at 70 ° C. under a nitrogen atmosphere, and the copolymerization is carried out for 16 hours. I let it. After completion of the polymerization reaction, the polymerization solution was added dropwise to 1,000 g of n-hexane for coagulation and purification. To the obtained solid, 150 g of propylene glycol monomethyl ether was added again, and 150 g of methanol, 34 g of triethylamine and 6 g of water were further added. In addition, a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained solid was dissolved in 150 g of acetone, and then dropped into 2,000 g of water to coagulate. The resulting solid was filtered, and filtered at 50 ° C. for 17 hours. The polymer was dried to obtain a white powdery polymer (A-8) (yield 63.8 g, 72.3%). Mw of the polymer (A-8) was 6,400, and Mw / Mn was 1.72. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from the compound (M-1) and the compound (M-15) was 51.2 mol% and 48.8 mol%, respectively.

[Synthesis Example 9] (Synthesis of polymer (E-1))
As shown in Table 2 below, compound (M-16) 5.16 g (20 mol%), compound (M-17) 11.46 g (40 mol%), compound (M-18) 13.38 g (40 mol%) %) Was dissolved in 20 g of 2-butanone, and 1.16 g (5 mol% based on all monomers) of azobisisobutyronitrile was further dissolved as a polymerization initiator to prepare a monomer solution. Next, a 100 mL three-necked flask containing 10 g of 2-butanone was heated to 80 ° C. while stirring under a nitrogen atmosphere, and the prepared monomer solution was added dropwise over 3 hours. After completion of the dropwise addition, the polymerization reaction was carried out by heating at 80 ° C. for 3 hours. After the completion of the polymerization reaction, the reaction solution was cooled to room temperature. After the reaction solution was transferred to a separating funnel, the reaction solution was uniformly diluted with 45 g of n-hexane, and 180 g of methanol was added and mixed. Next, 9 g of distilled water was added, and the mixture was further stirred and allowed to stand for 30 minutes. Next, the lower layer was recovered and the solvent was replaced with propylene glycol monomethyl ether acetate to obtain a propylene glycol monomethyl ether acetate solution containing the polymer (E-1) as a solid content (yield: 72.0%). . Mw of the polymer (E-1) was 7,300, and Mw / Mn was 2.00. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from compound (M-16), compound (M-17), and compound (M-18) was 20.1 mol% and 38.9 mol, respectively. %, 41.0 mol%.

<Synthesis of [B] compound>
[Synthesis Example 10] (Synthesis of compound (B-1))
In a 200 mL round bottom flask, 3.30 g (34 mmol) of 2-cyclohexen-1-one, 12.64 g (62.3 mmol) of ethyl bromodifluoroacetate, 4.64 g (74 mmol) of copper powder, and 40 mL of tetrahydrofuran were added, and under a nitrogen atmosphere. And heated and stirred at 50 ° C. 2.03 g (17.5 mmol) of tetramethylethylenediamine and 1.89 g (34.3 mmol) of acetic acid were added dropwise in this order. After completion of the dropwise addition, the mixture was stirred for 8 hours under reflux conditions. After the reaction was stopped by adding a saturated aqueous ammonium chloride solution, ethyl acetate was added, and the organic layer was washed twice with a saturated aqueous ammonium chloride solution. After evaporating the solvent, the residue was purified by column chromatography to obtain 7.17 g (yield 95%) of an intermediate (B'-1).

  Next, 7.17 g (32.6 mmol) of the intermediate (B'-1) and 50 mL of THF were added to a 200 mL round bottom flask, and the mixture was stirred at room temperature. An aqueous solution in which 0.94 g (39.1 mmol) of lithium hydroxide was dissolved in 17.9 g of water was added dropwise thereto. After completion of the dropwise addition, the mixture was stirred at room temperature for 2 hours. 9.74 g (32.6 mmol) of triphenylsulfonium chloride, 240 mL of dichloromethane and 120 mL of water were added thereto, and the mixture was stirred at room temperature for 10 hours. After recovering the organic layer, it was washed three times with water. After evaporating the solvent, the residue was purified by column chromatography to obtain 5.46 g (yield 35%) of compound (B-1).

[Synthesis Examples 2 to 13] (Synthesis of Compounds (B-2) to (B-4) and (B-7) to (B-13))
By appropriately selecting a precursor and performing the same operation as in Synthesis Example 1, compounds represented by the following formulas (B-2) to (B-4) and (B-7) to (B-13) are obtained. Synthesized.

[Synthesis Example 5] (Synthesis of Compound (B-5))
In a 200 mL round-bottomed flask, 8.82 g (45.4 mmol) of compound (B-2) obtained by the same operation as in Synthesis Example 1, 10.73 g (90.8 mmol) of pinacol, paratoluenesulfonic acid monohydrate 0.86 g (4.54 mmol) and 250 mL of toluene were added, and the mixture was stirred under reflux conditions for 12 hours. After cooling to room temperature, the mixture was washed twice with a saturated aqueous solution of sodium hydrogen carbonate. After evaporating the solvent, the residue was purified by column chromatography to obtain 3.61 g (yield 27%) of an intermediate (B ″ -5). A compound represented by the following formula compound (B-5) was synthesized by the same operation as in the method for obtaining compound (B-1) from '-1).

[Synthesis Example 6] (Synthesis of Compound (B-6))
By performing the same operation as in Synthesis Example 5, a compound represented by the following formula (B-6) was synthesized.

<Preparation of radiation-sensitive resin composition>
Other acid diffusion controllers, [C] solvents and [D] compounds used for preparing the radiation-sensitive resin compositions of the following Examples and Comparative Examples are shown below.

[Other acid diffusion control agents]
The compounds represented by (BB-1) to (BB-2), which are photodegradable bases, were used as other acid diffusion controllers.

[[C] solvent]
C-1: propylene glycol monomethyl ether acetate C-2: cyclohexanone C-3: γ-butyrolactone

[[D] compound]
[D] Compounds represented by the following formulas (D-1) to (D-6) were used.

<Formation of resist pattern (1)> (ArF exposure, alkali development)
[Example 1]
100 parts by mass of polymer (A-1), 7.9 parts by mass of compound (D-1), 1.6 parts by mass of compound (B-1), 3.0 parts by mass of polymer (E-1), solvent ( C-1) 2,240 parts by mass, 960 parts by mass of the solvent (C-2) and 30 parts by mass of the solvent (C-3) are mixed, and the obtained mixed solution is filtered through a filter having a pore size of 0.20 μm. A radiation-sensitive resin composition of Example 1 was prepared.

[Examples 2 to 24 and Comparative Examples 1 and 2]
The radiation-sensitive resin compositions of Examples 2 to 24 and Comparative Examples 1 and 2 were prepared in the same manner as in Example 1, except that the components and the amounts of the components shown in Table 3 below were used.

  Using a spin coater ("CLEAN TRACK ACT12" manufactured by Tokyo Electron) on the surface of a 12-inch silicon wafer, a composition for forming a lower antireflection film ("ARC66" manufactured by Brewer Science) was applied, and then 205 ° C. For 60 seconds to form a lower antireflection film having an average thickness of 105 nm. Each of the radiation-sensitive resin compositions prepared above was applied onto the lower antireflection film using the spin coater, and subjected to PB at 90 ° C. for 60 seconds. Thereafter, cooling was performed at 23 ° C. for 30 seconds to form a resist film having an average thickness of 90 nm. Next, this resist film was subjected to an optical condition of NA = 1.3 and dipole (Sigma 0.977 / 0.782) using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON). , 40 nm line and space (1L1S) mask pattern. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, alkali development was performed using a 2.38% by mass aqueous solution of TMAH as an alkali developer, washed with water, and dried to form a positive resist pattern. In forming the resist pattern, the exposure amount when a pattern formed through a one-to-one line-and-space mask having a target size of 40 nm is formed in a one-to-one line-and-space having a line width of 40 nm is determined as an optimum exposure amount. And

<Evaluation of resist pattern (1) (ArF exposure, alkali development)>
Each radiation-sensitive resin composition was evaluated by measuring the resist pattern formed in each of Examples 1 to 24 and Comparative Examples 1 and 2 (ArF exposure, alkali development) according to the following method. Note that a scanning electron microscope (“CG-4100” manufactured by Hitachi High-Technologies Corporation) was used for measuring the length of the resist pattern.

[Development defect suppression]
The number of defects in the resist pattern resolved at the optimum exposure amount was measured using a defect inspection apparatus (“KLA2810” manufactured by KLA-Tencor). The smaller the number of defects per unit area, the better the defect suppression properties.

[WM (watermark) defect suppression]
Similarly to the above method, a resist film having an average thickness of 90 nm was formed. Next, using an ArF excimer laser immersion exposure apparatus (“XT1900i” manufactured by ASML), NA = 1.3, optical conditions of a dipole (Sigma 0.977 / 0.782), 568 nm / s. Exposure was performed at a scan speed of Subsequently, after the PIR (post immersion rinse) after exposure was allowed to stand for 60 seconds, PEB was performed at 90 ° C. for 60 seconds. Thereafter, alkali development was performed using a 2.38% by mass aqueous solution of TMAH as an alkali developer, washed with water, and dried to form a positive-type resist pattern for WM defect evaluation. In forming the resist pattern, the exposure amount when a pattern formed through a one-to-one line-and-space mask having a target size of 40 nm is formed in a one-to-one line-and-space having a line width of 40 nm is determined as an optimum exposure amount. It was.

  Next, the number of defects in the resist pattern resolved at the above optimum exposure amount was measured using a defect inspection apparatus (“KLA2810” manufactured by KLA-Tencor). Among the defects, missing type defects were counted as WM defects. The smaller the number of defects per unit area, the better the defect suppression properties.

[Storage stability (1)]
Regarding the radiation-sensitive resin composition immediately after the preparation and the radiation-sensitive resin composition stored at 25 ° C. for 3 months after the preparation, the pattern formed through a 40 nm one-to-one line-and-space mask has a line width. The exposure amount (optimal exposure amount) when each was formed in a 40 nm one-to-one line and space was measured, the optimal exposure amount of the radiation-sensitive resin composition immediately after preparation was Ea, and after storage for 3 months after preparation, The optimal exposure amount of the radiation-sensitive resin composition of Example 1 was defined as Eb. Then, (Ea−Eb) × 100 / Ea was calculated and used as an index of storage stability. The storage stability can be evaluated as good when (Ea−Eb) × 100 / Ea is −1.00 or more and 1.00 or less, and as poor when less than −1.00 or more than 1.00. .

[Storage stability (2)]
After the examples (J-1) to (J-24) and the comparative examples (JJ-1) to (JJ-2) of the above photoresist composition were stored at 35 ° C. for 3 months, the degree of turbidity of the solution was visually observed. Confirmed.

  Table 4 below shows the evaluation results of the resist patterns (1) (ArF exposure, alkali development) formed from Examples 1 to 24 and Comparative Examples 1 and 2.

<Formation of resist pattern (3)> (Electron beam exposure, alkali development)
[Example 25]
100 parts by mass of polymer (A-8), 20 parts by mass of compound (D-3), 3.2 parts by mass of compound (B-1), 4,280 parts by mass of solvent (C-1), and solvent (C-2) ) 1,830 parts by mass were blended, and the mixture was filtered through a membrane filter having a pore size of 0.2 µm to prepare a radiation-sensitive resin composition of Example 25.

[Examples 26 to 28 and Comparative Examples 3 to 4]
The radiation-sensitive resin compositions of Examples 26 to 28 and Comparative Examples 3 and 4 were prepared in the same manner as in Example 25, except that the components and the amounts of the components shown in Table 5 below were used.

Next, using a spin coater ("CLEAN TRACK ACT8" from Tokyo Electron), each radiation-sensitive resin composition described in Table 5 above was applied to the surface of an 8-inch silicon wafer, and PB was applied at 90 ° C for 60 seconds. Was done. Thereafter, the resultant was cooled at 23 ° C. for 30 seconds to form a resist film having an average thickness of 50 nm. Next, the resist film was irradiated with an electron beam using a simple electron beam lithography system (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A / cm ² ). After the irradiation, PEB was performed at 120 ° C. for 60 seconds. Thereafter, the resist film was developed with a 2.38% by mass aqueous solution of TMAH as an alkaline developer at 23 ° C. for 30 seconds, washed with water and dried to form a positive resist pattern.

<Evaluation of resist pattern (3) (electron beam exposure, alkali development)>
The resist pattern formed for each of Examples 25 to 28 and Comparative Examples 3 to 4 (electron beam exposure, alkali development) was measured in accordance with the following method, and the development defect suppressing property was measured in the same manner as in the case of ArF exposure. Evaluation of storage stability (1) was performed. In addition, as described above, the radiation-sensitive resin compositions (J-30) to (J-33) and (JJ-3) to (JJ-4) were evaluated at 35 ° C. for 3 months to evaluate the storage stability (2). After storage, the turbidity of the solution was visually checked.

  Table 6 below shows the evaluation results of the resist pattern (3) (electron beam exposure, alkali development) formed from Examples 25 to 28 and Comparative Examples 3 and 4.

  As is clear from the results in Tables 4 and 6, the radiation-sensitive resin compositions of Examples are based on ArF exposure based on development defect suppression, WM defect suppression, and optimal exposure after storage at room temperature for 3 months. It was excellent in all evaluation items of storage stability (1) and storage stability (2) based on white turbidity after storage at 35 ° C. for 3 months. In addition, the radiation-sensitive resin compositions of Examples were excellent in all the evaluation items of the development defect suppressing property and the storage stability (1) and (2) in electron beam exposure.

  On the other hand, Comparative Example 1, which did not contain a fluorine atom in the ArF exposure, was inferior in all items, and in particular, very poor in WM defect suppression and storage stability. In Comparative Example 2 containing six fluorine atoms, the WM defect suppression property and the storage stability (2) were excellent, but the development defect suppression property and the storage stability (1) were very poor. In Comparative Example 3, which did not contain a fluorine atom in electron beam exposure, development defect suppression was excellent, but storage stability (1) and (2) were very poor. In Comparative Example 4 containing six fluorine atoms, the storage stability (2) was excellent, but the development defect suppressing property was very poor. Generally, according to electron beam exposure, it is known that the same tendency as in the case of EUV exposure is exhibited. Therefore, according to the radiation-sensitive resin composition of the example, even in the case of EUV exposure, It is presumed to be excellent in development defect suppression, watermark defect suppression, storage stability, and the like.

  According to the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention, it is possible to form a resist pattern excellent in development defect suppression, watermark defect suppression, and storage stability. Therefore, they can be suitably used for pattern formation in semiconductor device manufacturing or the like where further miniaturization is expected to proceed.

Claims (8)

A first polymer having an acid dissociable group;
A first compound having an anion represented by the following formula (1):
A radiation-sensitive resin composition comprising a solvent and

(In formula (1), X, -C (= O) Y, -C (= O) OY, -C (GR X) 2 Y, -C (= O) NYY ', - S (= O) _{2 Y, -S (= O)} 2 OY, -S (= O) 2 NYY ', - C (= O) OC (= O) Y or -C (= O) N (Y ) C (= O) G is each independently an oxygen atom or a sulfur atom, R ^X is each independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x are Together with —G—C—G—, which are combined with each other, they form a ring structure having 4 to 20 ring members, R ¹ , R ² , R ³ , R ⁴ , Y and Y ′ are each independently A hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or Y or Y ′ and R ¹ , Y or Y ′ and R ² , Y or Y ′ and R ^3, or Y or Y ′ and R ⁴ But To form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded, provided that when R ^{1 to} R ⁴ are monovalent organic groups, R ^{1 to} R ⁴ are each a fluorine atom R ^f1 and R ^f2 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms.) A second compound that generates sulfonic acid by the action of radiation,
The radiation-sensitive resin composition according to claim 1, wherein the first compound is represented by the following formula (2).

(In the formula (2), X, R ^X , R ¹ , R ² , R ³ , R ⁴ , Y, Y ′, R ^f1 and R ^f2 are the same as those in the above formula (1). Z ⁺ is It is a monovalent cation.) The formula (1) and the above formula X is in (2), -C (= O ) Y, -C (= O) OY, -C (GR X) 2 Y, -S (= O) 2 Y, - _{S (= O) 2 OY,} -S (= O) 2 NYY - be ', C (= O) OC (= O) Y or -C (= O) N (Y ) C (= O) Y' , R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, or Y or Y ′ and R ¹ , Y or Y ′ and R ² , Y or Y ′ and R ³ or Y or 3. The radiation-sensitive composition according to claim 1, wherein Y ′ and R ⁴ represent an alicyclic structure or an aliphatic heterocyclic structure having 3 to 20 ring members formed together with the carbon atom to which they are bonded. ⁴ . Resin composition. 4. The radiation-sensitive resin composition according to claim 1, wherein R ^f1 and R ^f2 in the formulas (1) and (2) are each a fluorine atom. The radiation-sensitive resin composition according to any one of claims 1 to 4, wherein the first polymer has a structural unit represented by the following formula (3).

(In the formula (3), R ^A1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^A2 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^A3 and R A ^A4 is each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms, or when these groups are combined with each other, Represents a ring structure having 3 to 20 ring members, which is formed together with the carbon atom to be bonded.) A step of coating the radiation-sensitive resin composition according to any one of claims 1 to 5 on one surface side of the substrate,
Exposing the resist film obtained by the coating step,
Developing the exposed resist film. A method for producing an acid diffusion controller used in a radiation-sensitive resin composition,
A step of obtaining a compound represented by the following formula (c) by reacting a compound represented by the following formula (a) with a compound represented by the following formula (b):
A step of obtaining a compound represented by the following formula (d) by hydrolysis of an ester group of the compound represented by the following formula (c);
A step of obtaining a compound represented by the following formula (1 ′) by reacting a compound represented by the following formula (d) with a salt represented by the following formula (e): .

(In the formulas (a) to (e) and (1 ′), X represents —C (＝ O) Y, —C (＝ O) OY, —C (GR ^X ) ₂ Y, and —C (＝ O). _{NYY ', - S (= O} ) 2 Y, -S (= O) 2 OY, -S (= O) 2 NYY', - C (= O) OC (= O) Y or -C (= O) N is a group represented by N (Y) C (= O) Y ′, G is each independently an oxygen atom or a sulfur atom, and R ^X is each independently a monovalent organic group having 1 to 20 carbon atoms. Or two R ^x are joined together to form a ring structure having 4 to 20 ring members together with -GCCG- to which they are bonded, R ¹ ′, R ³ ′, R ⁴ ′, Y and Y ′ is each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or Y or Y ′ and R ¹ ′, Y or Y ′ and R ³ ′, or Y or Y ′ and ^{R 4} 'is, together with each other Which constitutes the ring structure formed ring members 3 to 20 together with the carbon atoms to which they are attached. However, R ^{1 ',} R 3' and, R 4 ^'when it is a monovalent organic group, R ^1' , R ³ ′ and R ⁴ ′ do not contain a fluorine atom, R ⁶ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ^f1 and R ^f2 are each independently a fluorine atom or A monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms, Q represents a chlorine atom, a bromine atom or an iodine atom, Z ⁺ represents a monovalent cation, and M ⁻ represents a monovalent anion. Is.) A first polymer having an acid dissociable group;
A compound represented by the following formula (1):
A method for producing a radiation-sensitive resin composition, comprising a step of mixing a solvent and

(In formula (1), X, -C (= O) Y, -C (= O) OY, -C (GR X) 2 Y, -C (= O) NYY ', - S (= O) _{2 Y, -S (= O)} 2 OY, -S (= O) 2 NYY ', - C (= O) OC (= O) Y or -C (= O) N (Y ) C (= O) G is each independently an oxygen atom or a sulfur atom, R ^X is each independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x are Together with —G—C—G—, which are combined with each other, they form a ring structure having 4 to 20 ring members, R ¹ , R ² , R ³ , R ⁴ , Y and Y ′ are each independently A hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or Y or Y ′ and R ¹ , Y or Y ′ and R ² , Y or Y ′ and R ^3, or Y or Y ′ and R ⁴ But To form a ring structure having 3 to 20 ring members together with the carbon atom to which they are bonded, provided that when R ^{1 to} R ⁴ are monovalent organic groups, R ^{1 to} R ⁴ are each a fluorine atom R ^f1 and R ^f2 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 4 carbon atoms.)