JP6882703B2 - Acid diffusion control agents and compounds - Google Patents

Description

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

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

In the formation of such a resist pattern, the immersion exposure method is preferably 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 refractive index larger than that of air or an inert gas for exposure. According to this immersion exposure method, even when the numerical aperture of the lens is increased, the depth of focus is unlikely to decrease, and high resolution can be obtained.

As the radiation-sensitive resin composition used in such an immersion exposure method, it is necessary to suppress elution of a radiation-sensitive acid generator or the like from the resist film into the immersion medium and improve the drainage of the resist film. For the purpose, those containing a fluorine atom-containing polymer having high water repellency have been proposed (see International Publication No. 2007/116664).

International Publication No. 2007/116664

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

The present invention has been made based on the above circumstances, and an object of the present invention is a radiation-sensitive resin composition having excellent development defect suppressing property and water mark defect suppressing property, and a resist pattern forming method using the same. It is an object of the present invention to provide a method for producing an acid diffusion control agent 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 problems is a radiation-sensitive resin containing a first polymer having an acid dissociative group, a first compound having an anion represented by the following formula (1), and a solvent. It is a composition.

(In the formula (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 is a '.G are each independently an oxygen atom or a sulfur atom .R ^X are each independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x is Together with -G-C-G- which are combined with each other and bonded to 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 independent of each other. 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 constitute a ring structure composed of ring members 3 to 20 together with the carbon atom bonded these aligned with each other. However, when R ¹ to R ⁴ is a monovalent organic group, R ¹ to R ⁴ is It does not contain a fluorine atom. R ^f1 and R ^f2 are independently fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 4 carbon atoms.)

Another invention made to solve the above problems includes a step of coating the radiation-sensitive resin composition on one surface side of the substrate and a step of exposing the resist film obtained by the coating step. This is a resist pattern forming method including the 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 problems is a method for producing an acid diffusion control agent used in a radiation-sensitive resin composition, which comprises a compound represented by the following formula (a) and the following formula (b). By the step of obtaining the compound represented by the following formula (c) by the reaction with the compound represented by the following formula (c), and by hydrolyzing the ester group of the compound represented by the following formula (c), the following formula (d) is used. A step of obtaining a compound represented by the following formula, and 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). This is a method for producing an acid diffusion control agent.

(In formulas (a) to (e) and (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 is a (Y) C (= O) Y '.G , the .R ^X are each independently oxygen atom or a sulfur atom, each independently, a monovalent organic group having 1 to 20 carbon atoms There are, or two R ^x 's are combined with each other and they combine to form a ring structure with 4 to 20 ring members. R ¹ ', R ³ ', R ⁴ ', Y and Y 'are each independently a monovalent organic group hydrogen atom or 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 'constitutes} a ring structure composed of ring members 3 to 20 together with the carbon atom bonded these aligned with each other. However, R ^1', R 3 ^'and, R ^4' is a monovalent organic is a group, ^{R 1} ', ^{R 3'} and, .R ^{6 R 4} 'do not contain fluorine atoms, ^{.R f1} and ^{R f2} is a monovalent hydrocarbon group having 1 to 20 carbon atoms, Independently, they are fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 4 carbon atoms. Q is a chlorine atom, a bromine atom or an iodine atom. Z ⁺ is a monovalent cation. M ^- is a monovalent anion.)

（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。） Yet another invention made to solve the above problems is radiation-sensitive, which comprises a step of mixing a first polymer having an acid dissociative group, a compound represented by the following formula (1), and a solvent. This is a method for producing a resin composition.

(In the formula (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 is a '.G are each independently an oxygen atom or a sulfur atom .R ^X are each independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x is Together with -G-C-G- which are combined with each other and bonded to 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 independent of each other. 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 constitute a ring structure composed of ring members 3 to 20 together with the carbon atom bonded these aligned with each other. However, when R ¹ to R ⁴ is a monovalent organic group, R ¹ to R ⁴ is It does not contain a fluorine atom. R ^f1 and R ^f2 are independently fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 4 carbon atoms.)

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

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

<Radiation-sensitive resin composition>
The radiation-sensitive resin composition contains the [A] polymer, the [B] compound, and the [C] solvent. The radiation-sensitive resin composition contains, as suitable components, a [D] compound that generates sulfonic acid by the action of radiation, and an [E] polymer having a larger mass content of fluorine atoms 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. By having the above structure, the radiation-sensitive resin composition 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 a structural unit (I). According to the radiation-sensitive resin composition, the acid dissociative group of the [A] polymer in the exposed portion is dissociated by the acid generated from the [B] compound or the like by irradiation with radiation, and the exposed portion and the unexposed portion are separated. There is a difference in solubility in the developer, and as a result, a resist pattern can be formed. The polymer [A] is usually the base polymer in the radiation-sensitive resin composition. The "base polymer" is a polymer having the highest content among the polymers constituting the resist pattern, and preferably occupies 50% by mass or more, more preferably 60% by mass or more.

[A] In addition to the structural unit (I), the polymer is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure or a combination thereof (hereinafter, also referred to as “structural unit (II)”), and a phenolic hydroxyl group. It is preferable to have a structural unit containing (hereinafter, also referred to as “structural unit (III)”) and / or a structural unit containing an alcoholic hydroxyl group (hereinafter, also referred to as “structural unit (IV)”), and the structural unit (hereinafter, also referred to as “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 dissociative 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)”). The polymer [A] may have one or more structural units (I). Hereinafter, the structural unit (I) will be described.

In the above formula (3), ^RA1 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. ^RA3 and ^RA4 are independently monovalent hydrocarbon groups having 1 to 20 carbon atoms, hydrogen atoms or monovalent oxyhydrocarbon groups having 1 to 20 carbon atoms, or these groups are mutually exclusive. It represents a ring structure having 3 to 20 ring members, which is composed of carbon atoms to which they are combined and 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 contain a cyclic structure and is composed only of a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The "alicyclic hydrocarbon group" refers to a hydrocarbon group containing only an alicyclic structure as a ring structure and not containing an aromatic ring structure, and refers to a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Contains both hydrocarbon groups. However, it does not have to be composed only of an alicyclic structure, and a chain structure may be included as a part thereof. The "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it does not have to be composed only of an aromatic ring structure, and a chain structure or an alicyclic structure may be included as a part thereof.

As ^RA1 , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable, from the viewpoint of copolymerizability of the monomer giving the structural unit (I).

R ^{A2, R A3} and Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by ^{R A4,} for example, a monovalent chain-like hydrocarbon group having 1 to 20 carbon atoms, 1 to 20 carbon atoms Examples thereof include a valent 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 ethenyl group, propenyl group, butenyl group;
Examples thereof include an alkynyl group such as an ethynyl group, a propynyl group and a butynyl group. Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, a methyl group, an ethyl group and an i-propyl group are more 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;
Monovalent monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopentenyl group and cyclohexenyl group;
Monovalent polycyclic alicyclic saturated hydrocarbon groups such as norbornyl group, adamantyl group, tricyclodecyl group and tetracyclododecane;
Examples thereof include monovalent polycyclic alicyclic unsaturated hydrocarbon groups such as norbornenyl group and 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 an aryl group such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, a naphthyl group, a methylnaphthyl group, an anthryl group and a methyl anthryl group;
Examples thereof include an aralkyl group such as a benzyl group, a phenethyl group, a naphthylmethyl group and an anthrylmethyl group.

Terminus of the monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by R ^A3 and ^{R A4,} for example for example ^{R A2,} bond side of the monovalent hydrocarbon groups exemplified as ^{R A3} and ^{R A4} Examples include a group to which an oxygen atom is bonded.

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 Alicyclic structure such as structure;
Aliphatic heterocyclic structures such as oxacyclopentane structure, thiacyclopentane structure, and azacyclopentane structure can be mentioned. Among these, the alicyclic structure is preferable, and the cyclohexane structure is more preferable.

The structural unit (I) is, for example, a structural unit represented by the following formulas (3-1) to (3-6) (hereinafter, also referred to as “structural unit (I-1) to (I-6)”) and the like. Can be mentioned.

In the above formula ^{(3-1) ~ (3-5),} R A1 ~R A4 is as defined in the above formula (3).
In the above equation (3-1), i is an integer of 1 to 4.
In the above equation (3-3), j is an integer of 1 to 4.
In the formula ^{(3-6), R A2 ',} R A3' and ^{R A4 'are} each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms.

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

As the structural unit (I), 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 is synonymous with the above formula (3).

The structural unit (I) is a structural unit derived from 1-alkyl-monocyclic cycloalkane-1-yl (meth) acrylate and a structure derived from 2-alkyl-polycyclic cycloalkane-2-yl (meth) acrylate. Units and structural units derived from 2- (cycloalkane-yl) propan-2-yl (meth) acrylate are preferred, and structural units derived from 1-i-propylcyclopentane-1-yl (meth) acrylate, 1-. 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 Derived from structural units derived from 2- (adamantan-1-yl) propan-2-yl (meth) acrylate and derived from 2- (cyclohexane-1-yl) propan-2-yl (meth) acrylate The structural unit to be used is more preferable.

As the lower limit of the content ratio of the structural unit (I), 10 mol% is preferable, 20 mol% is more preferable, 30 mol% is further preferable, and 40 mol% is more preferable with respect to all the structural units constituting the polymer [A]. % Is particularly preferable. 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) within 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. The polymer [A] has a structural unit (II) in addition to the structural unit (I), so that the solubility in a developing solution can be adjusted more appropriately, and as a result, the radiation-sensitive resin composition. The LWR performance of the object can be further improved. In addition, 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, ^RL1 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 sulton 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 meta) acrylate and structural units derived from sulton structure-containing (meth) acrylate are more preferred, and are derived from norbornan lactone-yl (meth) acrylate-derived structural unit, cyanonorbornan lactone-yl (meth) acrylate. Structural unit, structural unit derived from norbornan lactone-yloxycarbonylmethyl (meth) acrylate, structural unit derived from γ-butyrolactone-yl (meth) acrylate, structural unit derived from ethylene carbonate-ylmethyl (meth) acrylate, and Structural units derived from norbornan sulton-yl (meth) acrylate are more preferred.

When the polymer [A] has a structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 10 mol%, preferably 20 mol%, based on the total structural units in the [A] polymer. 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 (II) in the above range, the solubility of the polymer [A] in the developing solution can be adjusted more appropriately, and as a result, the LWR of the radiation-sensitive resin composition is obtained. 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 the radiation to be irradiated in the exposure step in the resist pattern forming method, the sensitivity of the [A] polymer is further enhanced by having the structural unit (III). Can be done.

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 from 0 to 3. When p is 2 or 3, the plurality of R ^15s may be the same or different. q is an integer of 1-3. However, p + q is 5 or less.

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

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^15, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, the carbon of the hydrocarbon group - terminal carbon-carbon or a bond side Examples thereof include a group (g) containing a divalent heteroatom-containing group, a group in which a part or all of the hydrogen atoms of the above-mentioned hydrocarbon group and group (g) are substituted with a heteroatom-containing group, and the like.

The monovalent hydrocarbon groups of 1 to 20 carbon atoms include the same groups as listed above ^{R A2, R A3} and ^{R A4.}

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

Examples of the divalent heteroatom-containing group contained between carbon-carbon or at the end on the bond hand side include -C (= O)-, -O-, -NR'-, -S-, and -C (=). S)-, a group combining these, and the like can be mentioned. R'is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. When these divalent heteroatom-containing groups contain ^{carbon atoms, the total number of carbon atoms contained in R 15} is 1 to 20 including those contained in these divalent heteroatom-containing groups.

Examples of the heteroatom-containing group in which the above-mentioned hydrocarbon group and group (g) are replaced with a part or all of the hydrogen atom include an oxo group (= O), a thioxo group (= S), a hydroxy group, and a carboxy group. , Sulfanyl group (-SH), amino group, cyano group, halogen atom and the like.

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

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

The structural unit (III) is, for example, a structural unit represented by the following formulas (4-1) to (4-4) (hereinafter, also referred to as “structural unit (III-1) to (III-4)”) and the like. Can be mentioned.

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

When the [A] polymer has a structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 10 mol%, preferably 20 mol%, based on all the structural units constituting the [A] polymer. Mol% is more preferred, 30 mol% is even more preferred, and 40 mol% is particularly preferred. 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 replaced 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 carrying out a reaction or the like.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing an alcoholic hydroxyl group. Since the polymer [A] has a structural unit (IV), its solubility in a developing solution can be adjusted more appropriately, and as a result, the LWR performance and the like of the radiation-sensitive resin composition are further improved. Can be made to. In addition, the adhesion 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, ^RL2 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 [A] polymer has a structural unit (IV), the lower limit of the content ratio of the structural unit (IV) is preferably 10 mol%, preferably 20 mol%, based on all the structural units constituting the [A] polymer. Mol% is more preferred, 30 mol% is even more preferred, and 40 mol% is particularly preferred. 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 (IV) to the above range, the solubility of the polymer [A] in a developing solution can be further adjusted more appropriately, and as a result, the LWR of the radiation-sensitive resin composition is obtained. 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 above structural units (I) to (IV). The other structural units include, for example, 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 ( Examples include structural units derived from meta) acrylic acid esters. As the upper limit of the content ratio of the other structural units, 20 mol% is preferable and 10 mol% is more preferable with respect to all the structural units constituting the polymer [A].

The lower limit of the content of the polymer [A] is preferably 70% by mass, more preferably 80% by mass, and even more preferably 85% by mass, based on the total solid content of the radiation-sensitive resin composition. The “total solid content” refers to the sum of the 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] Polymer synthesis method>
The polymer [A] can be synthesized, for example, by polymerizing a monomer giving each structural unit in an appropriate 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). Propionitrile), 2,2'-azobis (3,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate and other azo radical initiators;
Examples thereof include peroxide-based radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferable, and AIBN is more preferable. These radical polymerization initiators can be used alone or in admixture 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, cumene;
Halogenated hydrocarbons such as chlorobutane, bromohexane, dichloroethane, hexamethylenedibromid, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate;
Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. The solvent used for these polymerizations may be used alone or in combination of two or more.

The lower limit of the reaction temperature in the polymerization is preferably 40 ° C, more preferably 50 ° C. 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, more preferably 24 hours.

[A] As the lower limit of the polystyrene-equivalent weight average molecular weight (Mw) of the polymer by gel permeation chromatography (GPC), 1,000 is preferable, 3,000 is more preferable, 4,000 is further preferable, and 5, 000 is particularly preferable. As the upper limit of the Mw, 50,000 is preferable, 30,000 is more preferable, 20,000 is further preferable, and 10,000 is particularly preferable. By setting the Mw of the polymer in the above range, the coatability of the radiation-sensitive resin composition is improved, and the ability to suppress development defects is further improved.

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

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

In the above formula (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 an oxygen atom or a sulfur atom independently of each other. ^{Each RX} is independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x 's are combined with each other and they are bonded to each other, and the number of ring members is 4 to 20 together with -GC-G-. Consists of the ring structure of. R ¹ , R ² , R ³ , R ⁴ , Y and Y'are independent hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms, or Y or Y'and R ¹ , respectively. Y or Y'and R ² , Y or Y'and R ³ or Y or Y'and R ⁴ form a ring structure having 3 to 20 ring members, which are combined with each other and composed of 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 independently fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 4 carbon atoms.

The radiation-sensitive resin composition is excellent in developing defect suppressing property and watermark defect suppressing property by containing the compound [B] in addition to the polymer [A] and the solvent [C]. The reason why the radiation-sensitive resin composition has the above-mentioned structure and exerts the above-mentioned effect is not always clear, but can be inferred as follows, for example. That is, the anion of the [B] compound ^{has two fluorine atoms bonded to the carbon atom to which −COO −} is bonded, and the hydrophobicity of the fluorine atom makes the entire hydrophobicity of the radiation-sensitive resin composition. It is considered that the solubility in the developing solution can be improved due to its electron attracting property while maintaining it. As a result, it is considered that the development defect suppressing property and the watermark defect suppressing property of the radiation-sensitive resin composition are improved. Further, when a conventional onium salt compound is contained as an acid diffusion control agent, precipitation of a sparingly soluble salt due to a decomposition reaction with the following [E] polymer is unavoidable, but according to the [B] compound. It is considered that the precipitation is suppressed, and as a result, the storage stability of the radiation-sensitive resin composition is improved, probably because of the moderately low nucleophilicity due to the structure of the formula (1).

The monovalent organic group of the -C ^(GR _{X) 2} Y having 1 to 20 carbon atoms represented by ^{R X,} for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, the carbon of the 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 a group in which all of the groups are substituted with a heteroatom-containing group.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a carbon number of carbon atoms. Examples thereof include 6 to 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 ethenyl group, propenyl group, butenyl group;
Examples thereof include an alkynyl group such as an ethynyl group, a propynyl group and a butynyl group.

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;
Monovalent monocyclic alicyclic unsaturated hydrocarbon groups such as cyclobutenyl group, cyclopentenyl group, cyclohexenyl group;
Monovalent polycyclic alicyclic saturated hydrocarbon group such as norbornyl group, adamantyl group, tricyclodecyl group, tetracyclododecyl group;
Examples thereof include monovalent polycyclic alicyclic unsaturated hydrocarbons such as norbornenyl group, tricyclodecenyl group and tetracyclododecenyl group.

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

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

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)-, groups combining these, and the like can be mentioned. When these divalent heteroatom-containing groups contain ^{carbon atoms, the total number of carbon atoms contained in Rx} is 1 to 20 including those contained in these divalent heteroatom-containing groups.

Examples of the hetero atom-containing group in which the hydrocarbon group and the group (g) are replaced with a part or all of the hydrogen atom include an oxo group (= O), a thioxo group (= S), a hydroxy group, and a carboxy group. , Sulfanyl group (-SH) and the like.

A ring structure having 4 to 20 ring members, which is composed of −GC—G— in which the above two ^Rx are combined with each other and bonded to each other, is a cyclic acetal ring such as 1,3-dioxacyclopentane (for example). A structure having a ring (including a cyclic ketal ring), a structure having a ring containing a group represented by -OC-S- such as 1-thia-3-oxacyclopentane, 1,3-dithiacyclopentane and the like. Examples thereof include a structure having a ring containing a group represented by −SC—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'are, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms. A group (g) containing a divalent heteroatom-containing group at the carbon-carbon end of the hydrocarbon group or at the end on the bond hand side, and a part or all of the hydrogen atoms of the above hydrocarbon group and group (g) are heteroatoms. Examples thereof include a group substituted with a containing group.

The monovalent hydrocarbon groups of 1 to 20 carbon atoms include the same groups as the groups listed above R ^X.

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

Examples of the divalent heteroatom-containing group contained between carbon-carbon or at the end on the bond hand side include -C (= O)-, -O-, -NR'-, -S-, and -C (=). S)-, a group combining these, and the like can be mentioned. 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 atom, the ^{R 1, R 2, R 3} , R 4, Y and Y 'in the heteroatom-containing group of divalent total number of carbon atom of the It is 1 to 20 including those included.

Examples of the heteroatom-containing group in which the above-mentioned hydrocarbon group and group (g) are replaced with a part or all of the hydrogen atom include an oxo group (= O), a thioxo group (= S), a hydroxy group, and a carboxy group. , Sulfanyl group (-SH), amino group, cyano group, 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 composed of carbon atoms to which they are bonded 3 to 20 ring members. As the ring structure of, for example, an alicyclic structure such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a norbornane structure, and an adamantane structure;
Aliphatic heterocyclic structures such as oxacyclopentane structure, thiacyclopentane structure, and azacyclopentane structure can be mentioned.

The ring structure may have any shape such as a single ring, a double ring, a condensed ring, and a bridging structure. 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 are combined with each other and composed of 3 to 20 carbon atoms to which they are bonded. Examples of the ring structure of the above include a ring structure represented by the following formula.

Among these, as the ring structure, 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 preferable, and a trifluoromethyl group is further preferable.

^{The above X is -C (= O) Y, -C (= O) OY, -C (OR X} ) ₂ from the viewpoint of further enhancing the storage stability and development defect suppressing property of the radiation-sensitive resin composition. 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', and R ¹ , R ² , R ³ and R ⁴ are independent hydrogen atoms, or Y or Y'and R ¹ , Y or Y'and R. ^2. Representing an alicyclic structure or an aliphatic heterocyclic structure having 3 to 20 ring members, in which Y or Y'and R ³ or Y or Y'and R ⁴ are combined with each other and composed of carbon atoms to which they are bonded. Is more preferable.

The R ¹ , R ² , R ³ and R ⁴ are more preferably hydrogen atoms from the viewpoint of further enhancing the storage stability and the ability to suppress development defects of the radiation-sensitive resin composition.

The R ^f1 and R ^f2 are more preferably fluorine atoms from the viewpoint of further enhancing the storage stability and the ability to suppress development defects of the radiation-sensitive resin composition.

The compound [B] 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 above formula (2), X, ^RX , R ¹ , R ² , R ³ , R ⁴ , Y, Y', R ^f1 and R ^f2 are synonymous with the above 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. Can be mentioned. 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 and the like.

The sulfonium cation includes, for example, a cation represented by the following formula (Q-1), and the tetrahydrothiophenium cation includes, for example, 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 are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, substituted or unsubstituted. aromatic hydrocarbon group having 6 to 12 carbon atoms, or an -OSO ₂ -R ^{P 'or} _-SO 2 -R ^Q', or two or more are combined with each other configured ring of these groups Represents. R P ^'and R ^Q' are each independently a substituted or unsubstituted, straight or branched alkyl group having 1 to 12 carbon atoms, alicyclic substituted or unsubstituted 5 to 25 carbon atoms carbide It is a hydrogen group or an substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2, and k3 are independently integers of 0 to 5. R ^c1 to R ^c3 and R ^{P 'and} R ^Q' if there are a plurality each of the plurality of ^R c1 ^{to R c3} and R ^{P 'and} R ^Q' may have respectively the same or different.
In the above formula (Q-2), R ^d1 is 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. Is the basis. k4 is an integer from 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 from 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 from 0 to 3.
In the above formula (Q-3), R ^e1 and R ^e2 are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, and substituted or unsubstituted carbon atoms 6 respectively. Represents a ring structure consisting of ~ 12 aromatic hydrocarbon groups, -OSO _2- ^RR or -SO _2- ^RS , or two or more of these groups combined with each other. R ^R and R ^S are each independently a substituted or unsubstituted, straight or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms Alternatively, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k6 and k7 are independently integers of 0 to 5. R ^{e1, R} e2, ^R when ^R and ^{R S} is plural respective plurality of ^{R e1,} R e2, ^{R R} and ^{R S} may have respectively 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 so on.
Examples of the ^{unsubstituted branched alkyl group represented by R c1 to} R ^c3 , R ^d1 , R ^d2 , R ^e1 and R ^e2 include an i-propyl group, an i-butyl group, a sec-butyl group and t. -Butyl group and the like can be mentioned.
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 xsilyl group, a mesityl group and a naphthyl group; a benzyl group, Examples thereof include an aralkyl group such as a phenyl group.
Examples of the ^{unsubstituted aromatic hydrocarbon group represented by R d1} and R ^d2 include a phenyl group, a tolyl group, a benzyl group and the like.

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

Examples of R ^{c1 to} R ^c3 , R ^d1 , R ^d2 , R ^e1 and R ^e2 include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, and an unsubstituted monovalent aromatic hydrocarbon group. , -OSO _2- R ^** , -SO _2- R ^** are preferred, fluorinated alkyl groups, unsubstituted monovalent aromatic hydrocarbon groups are more preferred, and fluorinated alkyl groups are 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.
As k4 in the above formula (Q-2), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 1 is further preferable. As k5, an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable.
As k6 and k7 in the above formula (Q-3), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable.

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

Among these, the cation represented by the above formula (i-1) and the 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, the cation represented by the above formula (ii-11) is preferable.

Examples of the [B] compound include compounds represented by the following formulas (B-1) to (B-17) (hereinafter, also referred to as "compound (B-1) to compound (B-17)"). Be done.

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

The method for producing the compound [B], which is an acid diffusion control agent, is represented by the following formula (c), for example, by reacting the compound represented by the following formula (a) with the compound represented by the following formula (b). The step of obtaining the compound represented by the following formula (d) by hydrolyzing the ester group of the compound represented by the following formula (c), and the step of obtaining the compound represented by the following formula (d). It is provided with a step of obtaining a compound represented by the following formula (1') by reacting with a salt represented by the following formula (e).

As the compound [B], 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 form} a ring structure. The following compound (1'), which is not formed, can be synthesized, for example, according to the following reaction scheme. By the above method, the compound [B] can be synthesized easily and in good yield. Compounds [B] other than these can also be synthesized by using known methods.

In the above formulas (a) to (e) and (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 an oxygen atom or a sulfur atom independently of each other.
^{Each RX} is independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x 's are combined with each other and they are bonded to each other, and the number of ring members is 4 to 20 together with -GC-G-. Consists of the ring structure of.
R ¹ ', R ³ ', R ⁴ ', Y and Y'are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms, or Y or Y'and R ¹ '. , Y or the Y 'and R ^3' or Y or Y 'and R ^4', constitute a ring structure composed of ring members 3 to 20 together with the carbon atom to which they are bonded aligned with each other. However, ^{R 1} ', ^{R 3'} and, 'when it is a monovalent organic group, ^{R 1' R 4, R 3} 'and, ^{R 4'} contains no fluorine atom.
R ⁶ is a monovalent hydrocarbon group having 1 to 20 carbon atoms.
R ^f1 and R ^f2 are independently fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 4 carbon atoms.
Q is a chlorine atom, a bromine atom or an iodine atom.
Z ⁺ is a monovalent cation.
M ^- is a monovalent anion.

The ^{R 1 ', R 3',} ' The monovalent organic group having 1 to 20 carbon atoms represented by said ^{R 1, R 2, R 3} , R 4, Y and Y' ^{R 4} listed A group similar to the group 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 mentioned in ^{RA 2} , RA 3 and RA ^4.

As the lower limit of the content of the compound [B], 0.1 part by mass is preferable, 0.5 part by mass is more preferable, and 1 part by mass is further preferable with respect to 100 parts by mass of the polymer of [A]. The upper limit of the content of the compound [B] is preferably 25 parts by mass, more preferably 20 parts by mass, further preferably 15 parts by mass, and particularly preferably 10 parts by mass with respect to 100 parts by mass of the polymer [A]. .. If the content of the compound [B] is less than the above lower limit, the lithography performance such as the resolution of the radiation-sensitive resin composition may deteriorate. If 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 [C] solvent. The solvent [C] is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the [B] compound, the [E] polymer, the [D] compound contained if necessary, and the like.

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

Examples of the alcohol solvent include, for example.
Aliphatic monoalcoholic solvents with 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcoholic solvent having 3 to 18 carbon atoms such as cyclohexanol;
Polyhydric alcohol solvent with 2 to 18 carbon atoms such as 1,2-propylene glycol;
Examples thereof include a polyhydric alcohol partial ether solvent 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 solvent such as tetrahydrofuran and tetrahydropyran;
Examples thereof include aromatic ring-containing ether-based solvents such as diphenyl ether and anisole (methylphenyl ether).

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, trimethylnonanone and other chain ketone solvents:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and methylcyclohexanone:
Examples thereof include 2,4-pentandione, acetonylacetone and acetophenone.

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

Examples of the ester solvent include, for example.
Monocarboxylic acid ester solvent such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvent such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvent such as propylene glycol monomethyl ether acetate;
Lactone-based solvents such as γ-butyrolactone and δ-valerolactone;
Polyvalent carboxylic acid diester solvent such as diethyl oxalate;
Examples thereof include carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate and propylene carnate.

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

Among these, as the [C] solvent, an ester solvent and a ketone solvent are preferable, a polyhydric alcohol partial ether carboxylate solvent, a lactone solvent, and a cyclic ketone solvent are more preferable, and a polyhydric alcohol partial alkyl ether is preferable. Acetates, lactone-based solvents, and cyclic ketone-based solvents are more preferable, and propylene glycol monomethyl ether acetate, γ-butyrolactone, and cyclohexanone are particularly preferable. The radiation-sensitive resin composition may contain one or more [C] solvents.

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

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

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

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

As the [D] compound, a compound represented by the following formula (vi) is preferable. By making the compound [D] a compound represented by the following formula (vi), the acid generated by the action of radiation due to the interaction with the [E] polymer or the polar structure of the [A] polymer, etc. It is considered that the diffusion length in the resist film is more appropriately shortened, 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 R b1} refers to the number of atoms constituting the rings of the alicyclic structure and the aliphatic heterocyclic structure, and in the case of the polycyclic alicyclic structure and the polycyclic aliphatic heterocyclic structure, this is used. The number of atoms that make up a polycycle.

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

As the ^{monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members represented by R b1} , for example, a group containing a lactone structure such as norbornane lactone-yl group;
Norbornane sultone-a group containing a sultone structure such as an yl group;
Oxygen atom-containing heterocyclic groups such as oxacycloheptyl group and oxanorbornyl group;
Nitrogen atom-containing heterocyclic groups such as azacyclohexyl group, azacycloheptyl group, diazabicyclooctane-yl group;
Examples thereof include a sulfur atom-containing heterocyclic group such as a thiacycloheptyl group and a thianorbornyl group.

The ^{number of ring members of the group represented by R b1} is preferably 8 or more, more preferably 9 to 15, and even more preferably 10 to 13 from the viewpoint of further making the diffusion length of the acid more appropriate.

Among these, as the R ^b1 , 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 group are preferable. Groups, norbornane lactone-yl groups, 5-oxo-4-oxatricyclo [4.3.1.1 ^3,8 ] undecane-yl groups are more preferred, and adamantyl groups are even more preferred.

The ^{fluorinated alkanediyl group having 1 to 10 carbon atoms represented by R b2} is, for example, one or more hydrogen atoms of an alkanediyl group having 1 to 10 carbon atoms such as a methanediyl group, an ethanediyl group, and a propanediyl group. Examples thereof include a group in which is substituted 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 groups, 1,1-difluoroethanediyl groups, 1,1,3,3,3-pentafluoro-1,2-propanediyl groups, 1,1 , 2,2-Tetrafluoroethanediyl group, 1,1,2,2-tetrafluorobutandyl group, 1,1,2,2-tetrafluorohexanediyl group are more preferable.

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 [D] compound include compounds represented by the following formulas (vi-1) to (vi-17) (hereinafter, also referred to as "compounds (vi-1) to (vi-17)"). Be done.

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

As the lower limit of the content of the compound [D], 0.1 parts by mass is preferable, 0.5 parts by mass is more preferable, and 1 part by mass is more preferable with respect to 100 parts by mass of the polymer of [A], and 3 parts by mass. Part is particularly preferable. The upper limit of the compound [D] is preferably 40 parts by mass, more preferably 30 parts by mass, and even more preferably 25 parts by mass with respect to 100 parts by mass of the polymer [A]. As the [D] compound, one kind or two or more kinds can be used.

<[E] Polymer>
The [E] polymer is a polymer containing a fluorine atom. The polymer [E] preferably has at least one of the following structural units (V) and structural units (VI). When the resist film is formed by containing the [E] polymer, the radiation-sensitive resin composition has an uneven distribution on the surface layer of the resist film due to the oil-repellent characteristics of the [E] polymer. There is a tendency, and it is possible to prevent the [D] compound, the acid diffusion control agent, and the like from being eluted into the immersion liquid during immersion exposure. Further, due to the water-repellent characteristic of this [E] polymer, the forward 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 becomes high, and high-speed scan exposure can be performed without leaving water droplets. Further, also in electron beam exposure and EUV exposure, the defect suppressing property of the resist film can be improved due to the water-repellent characteristics of the [E] polymer. By containing the [E] polymer in the radiation-sensitive resin composition as described above, a resist film suitable for immersion exposure, electron beam exposure, EUV exposure and the like can be formed.

The [E] polymer preferably has a larger total mass content of fluorine atoms than the [A] polymer in the radiation-sensitive resin composition. Since the [E] polymer has a higher total mass content of fluorine atoms than the [A] polymer, the degree of uneven distribution described above becomes higher, and the water repellency and elution inhibitory property of the obtained resist film surface can be improved. The characteristics can be further improved.

[E] As the lower limit of the mass content of fluorine atoms in the polymer, 1% by mass is preferable, 2% by mass is more preferable, 4% by mass is further preferable, and 7% by mass is particularly preferable. The upper limit of the total mass content is preferably 60% by mass, more preferably 40% by mass, and even more preferably 30% by mass. 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.}

The polymer [E] preferably has an alkali dissociative group. [E] When the polymer has an alkali dissociative group, the surface of the resist film can be effectively changed from hydrophobic to hydrophilic during alkaline development, and the ability to suppress development defects of the radiation-sensitive resin composition is improved. .. [E] When the polymer has an alkali dissociative group, ion exchange with a conventionally used onium salt compound or the like is likely to occur, and the storage stability and development defect suppression property of the radiation-sensitive resin composition are further lowered. .. However, since the radiation-sensitive resin composition uses the above-mentioned specific [B] compound as the onium salt compound, even when the [E] polymer has an alkali dissociative group, storage stability and development defect suppression property are maintained. It can be excellent. The "alkali dissociative group" is a group that replaces a hydrogen atom contained in a carboxy group, a hydroxy group, or the like, and dissociates in an alkaline aqueous solution (for example, a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C.). Refers to the group to be used.

[E] The form of the fluorine atom contained in the polymer is not particularly limited and may be bonded to any of the main chain, side chain and terminal, but a structural unit containing a fluorine atom (hereinafter, “structural unit (V)””. Also referred to as). [E] In addition to at least one of the structural unit (V) and the structural unit (VI), the polymer contains an acid dissociable group from the viewpoint of improving the inhibitory property of development defects of the radiation-sensitive resin composition. It is preferable to have a structural unit containing the structural unit (structural unit (I) in the [A] polymer 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)”). The fluorine atom content of the [E] polymer can be adjusted by having a structural unit (V).

In the above formula (5), ^R51 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} include a methyl group, an ethyl group, an n-propyl group, an n-butyl group and the like.

Examples ^{of the alkoxyalkyl group having 2 to 10 carbon atoms represented by R 51} include a methoxymethyl group, a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, an ethoxymethyl group, an ethoxyethyl group, an ethoxypropyl group and an ethoxybutyl group. Group etc. can be mentioned.

Examples of the divalent organic group having 1 to 20 carbon atoms represented by W, for example, of one hydrogen atom from a monovalent organic group of formula (4) carbon atoms exemplified as R ¹⁵ of 20 Excluded groups and the like can be mentioned.

Examples of the ^{monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R 52} include a monovalent chain 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 ethenyl group, propenyl group, butenyl group;
Examples thereof include an alkynyl group such as an ethynyl group, a propynyl group and a butynyl group.

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;
Monovalent monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopentenyl group and cyclohexenyl group;
Monovalent polycyclic alicyclic saturated hydrocarbon groups such as norbornyl group, adamantyl group and tricyclodecyl group;
Examples thereof include monovalent polycyclic alicyclic unsaturated hydrocarbon groups such as norbornenyl group and 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 xsilyl group, a naphthyl group and an anthryl group;
Examples thereof include an aralkyl group such as a benzyl group, a phenethyl group, a naphthylmethyl group and an anthrylmethyl group.

As the ^{monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R 52} , a chain hydrocarbon group and an alicyclic hydrocarbon group are preferable.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by ^{R 52 include a fluorinated alkyl group having 1 to 20 carbon atoms.} 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 a trifluoro are more preferable. Methyl groups are more preferred.

Further, from the viewpoint of further improving the effect as an alkali dissociative group, it is preferable that at least one of ^{W and R 52 is a group containing a fluorine atom.}

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

[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)”). The fluorine atom content of the [E] polymer can be adjusted by having a structural unit (VI).

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

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

As the G, -CO-O-, -SO ₂ -NH-, -CO-NH- or -O-CO-NH- is preferable, and -CO-O- is more preferable.

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, and 2 , 2,3,3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, perfluoron-propyl group, perfluoroi-propyl group, perfluoron-butyl Examples thereof include a group, a perfluoroi-butyl group, a perfluorot-butyl group, a 2,2,3,3,4,5,5-octafluoropentyl group and a perfluorohexyl group.

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 ^{R k,} among these, preferably fluorinated chain hydrocarbon group, a 2,2,2-trifluoroethyl group, 1,1,1,3,3,3-hexafluoro-2-propyl Groups are more preferred, and 1,1,1,3,3,3-hexafluoro-2-propyl groups are even more preferred.

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

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

<[E] Polymer synthesis method>
The [E] polymer can be synthesized, for example, by polymerizing a monomer giving each structural unit in an appropriate 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-cyclopropylpro). Pionitrile), 2,2'-azobis (3,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate and other azo radical initiators; benzoyl peroxide, t-butyl hydroperoxide, Examples thereof include peroxide-based radical initiators such as cumene hydroperoxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferable, and AIBN is more preferable. These radical initiators can be used alone or in admixture 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, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylenedibromid, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate;
Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. The solvent used for these polymerizations may be used alone or in combination of two or more.

The 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, 1 hour to 24 hours.

[E] The polystyrene-equivalent weight average molecular weight (Mw) of the polymer by gel permeation chromatography (GPC) is not particularly limited, but is preferably 1,000 or more and 50,000 or less, and more preferably 2,000 or more and 30,000 or less. Preferably, it is more preferably 2,500 or more and 20,000 or less, and particularly preferably 3,000 or more and 15,000 or less. 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] If 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 the 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. More preferably 1 or more and 2 or less.

<Other optional ingredients>
The radiation-sensitive resin composition may contain other optional components other than the above-mentioned [A] to [E] components. Examples of the other optional components include acid diffusion controllers other than the [B] compound, surfactants, alicyclic skeleton-containing compounds, sensitizers, and the like. 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. Other acid diffusion controllers control the diffusion phenomenon of the acid generated from the [D] compound in the resist membrane by the action of radiation. As a result, it has the effect of suppressing an unfavorable chemical reaction in the unexposed region. In addition, the storage stability of the obtained radiation-sensitive resin composition is further improved. Further, the resolution of the resist is further improved, and the change in the line width of the resist pattern due to the fluctuation of the leaving time from the exposure to the development process can be suppressed, so that a radiation-sensitive resin composition having excellent process stability can be obtained. .. As the content form of the other acid diffusion control body in the radiation-sensitive resin composition, even in the form of a free compound (hereinafter, appropriately referred to as “another acid diffusion control agent”), it is incorporated as a part of the polymer. Or both of these forms.

Examples of other acid diffusion control agents include compounds represented by the following formula (vii) (hereinafter, also referred to as “nitrogen-containing compound (I)”) and compounds having two nitrogen atoms in the same molecule (hereinafter, “nitrogen-containing compound (I)”). Examples thereof include a 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, and a nitrogen-containing heterocyclic compound. ..

In the above formula (vii), R ^f4 , R ^f5 and R ^f6 are independently hydrogen atoms, optionally substituted linear, branched or cyclic alkyl groups, aryl groups or aralkyl groups, respectively. ..

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

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, N-methylpyrrolidone and the like. Be done.

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

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

Further, as the nitrogen-containing organic compound, a compound having an acid dissociative group can also be used. Examples of the nitrogen-containing organic compound having such an acid dissociative group include Nt-butoxycarbonylpiperidin, 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-hydroxypiperidin, Nt-amyloxycarbonyl-4-hydroxypiperidin and the like.

Further, as another acid diffusion controller, a photodisintegrating base that generates a weak acid by the action of radiation can also be used. Examples of the photodisintegrating base include onium salt compounds that are decomposed by the action of radiation and lose their acid diffusion controllability (however, those corresponding to the [B] compound are excluded).

When the other acid diffusion control body is another acid diffusion control agent, the content of the other acid diffusion control body is 0 parts by mass to 20 parts by mass with respect to 100 parts by mass of the [A] polymer. Preferably, 0.1 part by mass to 15 parts by mass is more preferable, 0.3 parts by mass to 10 parts by mass is further preferable, and 0.5 parts by mass to 5 parts by mass is particularly preferable. If the content of the other acid diffusion control body 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 di. Nonionic surfactants such as stearate; Commercial products include "KP341" from Shinetsu Chemical Industry Co., Ltd., "Polyflow No.75" and "No.95" from Kyoeisha Chemical Co., Ltd., and "Ftop" from Tochem Products Co., Ltd. EF301, EF303, EF352, DIC's "Megafuck F171", "F173, Sumitomo 3M's" Florard FC430 "," FC431 ", Asahi Glass Industry's" Asahi Guard AG710 ", "Surflon S-382", "SC-101", "SC-102", "SC-103", "SC-104", "SC-105", "SC-106", etc. Can be mentioned. The content of the surfactant in the radiation-sensitive resin composition is usually 2 parts by mass or less with respect to 100 parts by mass of the [A] polymer.

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

[Sensitizer]
The sensitizer has an action of increasing the amount of acid produced from the [D] compound or the like, 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, biacetyls, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like. 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 with respect to 100 parts by mass of the [A] polymer.

<Manufacturing method of radiation-sensitive resin composition>
The method for producing the radiation-sensitive resin composition comprises, for example, a [A] polymer, a [B] compound, a [C] solvent, a [D] compound, an [E] polymer contained as necessary, or the like. A step of mixing at a ratio is provided. After mixing, the radiation-sensitive resin composition is preferably filtered with, for example, a filter having a pore size of about 0.2 μm. The total solid content concentration of the radiation-sensitive resin composition is usually 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 for forming a positive pattern using an alkaline developer and for forming a negative pattern using a developer containing an organic solvent. Of these, when used for forming a negative pattern using a developing solution 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 applying the radiation-sensitive resin composition to one surface side of the substrate (hereinafter, also referred to as a “coating step”) and a resist film obtained by the above coating step. A step of exposing the exposed resist film (hereinafter, also referred to as “exposure step”) and a step of developing the exposed resist film (hereinafter, also referred to as “development step”) are provided.

[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 this substrate. The method for 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 the radiation-sensitive resin composition is applied, the amount of the radiation-sensitive resin composition to be applied is adjusted so that the resist film to be formed has a desired film thickness. After applying the radiation-sensitive resin composition on the substrate, soft baking (hereinafter, also referred to as “SB”) may be performed to volatilize the solvent. The temperature of the soft bake is usually 30 ° C. to 200 ° C., preferably 50 ° C. to 150 ° C.

[Exposure process]
In this step, the resist film obtained by the above coating step is exposed. In some cases, 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 the case of immersion exposure, an immersion medium is placed on the resist film, and radiation is applied to the resist film through the immersion medium. As the immersion medium, a liquid having a refractive index larger than that of air is usually used. Specific examples thereof include pure water, long-chain or cyclic aliphatic compounds and the like. With the immersion medium passing through, that is, with the immersion medium filled between the lens and the resist film, radiation is irradiated from the exposure apparatus, and the resist film is exposed through a mask having a predetermined pattern. ..

Examples of the radiation include visible light, ultraviolet rays, far ultraviolet rays, vacuum ultraviolet rays (extreme ultraviolet rays (EUV); wavelength 13.5 nm), electromagnetic waves such as X-rays and γ-rays; charged particle beams such as electron beams and α-rays. Can be mentioned. In the case of immersion exposure, far ultraviolet rays typified 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.

In addition, post-exposure baking (PEB) may be performed after 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, 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 the substrate to be used. Further, in order to prevent the influence of basic impurities and the like contained in the environmental atmosphere, for example, a protective film may be provided on the coating film. Further, 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 process]
In this step, the resist film exposed in the above exposure step is developed. As a result, a resist pattern is formed.

Examples of the developing solution used for the above development include alkaline developing solutions 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. An appropriate amount of a water-soluble organic solvent such as alcohols such as methanol and ethanol and a surfactant can be added to this developer.

Further, as the developer, a developer containing an organic solvent can also be used. Examples of the organic solvent include one or more of the organic solvents exemplified as the [C] solvent 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 measurement method of various physical property values is shown below.

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

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

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

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

Of the above compounds, (M-1) to (M-7) and (M-16) have structural units (I), and (M-8) to (M-9) and (M-11) to (M-11) to ( M-14) is the structural unit (II), (M-15) is the structural unit (III), (M-10) is the structural unit (IV), and (M-17) is the structural unit (VI). , Compound (M-18) gives a structural unit (V), respectively.

[Synthesis Example 1] (Synthesis of Polymer (A-1))
As shown in Table 1 below, 9.38 g (50 mol%) of compound (M-1) and 10.62 g (50 mol%) of compound (M-8) are dissolved in 40 g of 2-butanone, and a polymerization initiator is further added. As a result, 0.785 g of azobisisobutyronitrile (5 mol% with respect to all the monomers) was dissolved to prepare a monomer solution. Next, a 200 mL three-necked flask containing 20 g of 2-butanone was heated to 80 ° C. with stirring under a nitrogen atmosphere, and the prepared monomer solution was added dropwise over 3 hours. After completion of the dropping, the polymerization reaction was carried out by heating at 80 ° C. for another 3 hours. After 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 separated solid was washed twice with 60 mL of methanol, filtered off, and then dried under reduced pressure at 50 ° C. for 15 hours to synthesize a polymer (A-1) (yield 15.8 g, yield 78.9). %). The Mw of the polymer (A-1) was 6,100, and the Mw / Mn was 1.41. ¹³ As a result of 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))
The polymers (A-2) to (A-7) shown in Table 1 below can be obtained by performing the same operations as in Synthesis Example 1 except that the monomers of the type and amount used shown in Table 1 below are used. Synthesized.

[Synthesis Example 8] (Synthesis of Polymer (A-8))
As shown in Table 1 below, 54.76 g (50 mol%) of compound (M-1), 45.24 g (50 mol%) of compound (M-15), and azobisisobutyronitrile as a polymerization initiator 4. After dissolving 58 g (5 mol% with respect to the total monomer) and 1,14 g of t-dodecyl mercaptan in 100 g of propylene glycol monomethyl ether, the reaction temperature was maintained at 70 ° C. under a nitrogen atmosphere, and copolymerization was carried out for 16 hours. I let you. After completion of the polymerization reaction, the polymerization solution was added dropwise to 1,000 g of n-hexane for coagulation and purification, and then 150 g of propylene glycol monomethyl ether was added again to the obtained solid, and 150 g of methanol, 34 g of triethylamine and 6 g of water were added. In addition, the hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, the obtained solid was dissolved in 150 g of acetone, and then dropped into 2,000 g of water to coagulate, and the produced solid was filtered and filtered at 50 ° C. for 17 hours. The mixture was dried to obtain a white powdery polymer (A-8) (yield 63.8 g, yield 72.3%). The Mw of the polymer (A-8) was 6400, and the Mw / Mn was 1.72. ¹³ As a result of C-NMR analysis, the content ratios of the structural units derived from the compound (M-1) and the compound (M-15) were 51.2 mol% and 48.8 mol%, respectively.

[Synthesis Example 9] (Synthesis of Polymer (E-1))
As shown in Table 2 below, 5.16 g (20 mol%) of compound (M-16), 11.46 g (40 mol%) of compound (M-17), and 13.38 g (40 mol%) of compound (M-18). %) Was dissolved in 20 g of 2-butanone, and 1.16 g of azobisisobutyronitrile (5 mol% with respect to all the monomers) 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. with stirring under a nitrogen atmosphere, and the prepared monomer solution was added dropwise over 3 hours. After completion of the dropping, the polymerization reaction was carried out by heating at 80 ° C. for another 3 hours. After completion of the polymerization reaction, the reaction solution was cooled to room temperature. After transferring the reaction solution to a separatory funnel, the reaction solution was uniformly diluted with 45 g of n-hexane, and 180 g of methanol was added and mixed. Then, 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%). .. The Mw of the polymer (E-1) was 7,300, and the Mw / Mn was 2.00. ¹³ As a result of C-NMR analysis, the content ratios of each structural unit derived from compound (M-16), compound (M-17), and compound (M-18) were 20.1 mol% and 38.9 mol, respectively. %, 41.0 mol%.

<Synthesis of [B] compound>
[Synthesis Example 10] (Synthesis of compound (B-1))
To a 200 mL round bottom flask, add 3.30 g (34 mmol) of 2-cyclohexene-1-one, 12.64 g (62.3 mmol) of ethyl bromodifluoroacetate, 4.64 g (74 mmol) of copper powder, and 40 mL of tetrahydrofuran, and add under a nitrogen atmosphere. The mixture was 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 dropping, the mixture was stirred under reflux conditions for 8 hours. After stopping the reaction by adding saturated aqueous ammonium chloride solution, ethyl acetate was added and the organic layer was washed twice with saturated aqueous ammonium chloride solution. After distilling off the solvent, the residue was purified by column chromatography to obtain 7.17 g (yield 95%) of the intermediate (B'-1).

Next, 7.17 g (32.6 m 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 prepared by dissolving 0.94 g (39.1 mmol) of lithium hydroxide in 17.9 g of water was added dropwise thereto. After completion of the dropping, 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 with water three times. After distilling off the solvent, it 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) can be obtained. Synthesized.

[Synthesis Example 5] (Synthesis of compound (B-5))
8.82 g (45.4 mmol) of compound (B-2), 10.73 g (90.8 mmol) of pinacol, paratoluenesulfonic acid monohydrate obtained in the same operation as in Synthesis Example 1 in a 200 mL round bottom flask. 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, it was washed twice with saturated aqueous sodium hydrogen carbonate solution. After distilling off the solvent, the mixture was purified by column chromatography to obtain 3.61 g (yield 27%) of the intermediate (B "-5). Next, the intermediate (B) described in Synthesis Example 1 was obtained. A compound represented by the following formula compound (B-5) was synthesized by the same operation as the method for obtaining the compound (B-1) from'-1).

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

<Preparation of radiation-sensitive resin composition>
Other acid diffusion control agents, [C] solvent and [D] compound used in the preparation of the radiation-sensitive resin compositions of the following Examples and Comparative Examples are shown below.

[Other acid diffusion regulators]
As another acid diffusion control agent, compounds represented by photodisintegrating bases (BB-1) to (BB-2) were used.

[[C] Solvent]
C-1: Propylene glycol monomethyl ether acetate C-2: Cyclohexanone C-3: γ-Butyrolactone

[[D] Compound]
As the [D] compound, the compounds represented by the following (D-1) to (D-6) were used.

<Formation of resist pattern (1)> (ArF exposure, alkaline 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 ( By mixing 2,240 parts by mass of C-1), 960 parts by mass of the solvent (C-2) and 30 parts by mass of the solvent (C-3), and filtering the obtained mixed solution with a filter having a pore size of 0.20 μm. The radiation-sensitive resin composition of Example 1 was prepared.

[Examples 2 to 24 and Comparative Examples 1 to 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 each component of the type and the blending amount shown in Table 3 below was used.

A composition for forming an underlayer antireflection film (“ARC66” by Brewer Science) was applied to the surface of a 12-inch silicon wafer using a spin coater (“CLEAN TRACK ACT12” by Tokyo Electron Limited), and then the temperature was 205 ° C. A lower antireflection film having an average thickness of 105 nm was formed by heating for 60 seconds. Each of the above-prepared radiation-sensitive resin compositions was applied onto the lower antireflection film using the spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 seconds to form a resist film having an average thickness of 90 nm. Next, this resist film was subjected to an ArF excimer laser immersion exposure apparatus (NIKON's "NSR-S610C") under optical conditions of NA = 1.3 and dipole (Sigma 0.977 / 0.782). , 40 nm line and space (1L1S) mask pattern was used for exposure. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Then, it was subjected to alkaline development using a 2.38 mass% TMAH aqueous solution as an alkaline developer, washed with water, and dried to form a positive resist pattern. When forming this resist pattern, the optimum exposure amount is the exposure amount when the pattern formed through a 1: 1 line-and-space mask having a target dimension of 40 nm is formed in a 1: 1 line-and-space pattern having a line width of 40 nm. And said.

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

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

[WM (watermark) defect suppression property]
Similar to the above method, a resist film having an average thickness of 90 nm was formed. Next, this resist film was subjected to NA = 1.3, optical conditions of Dipole (Sigma 0.977 / 0.782), 568 nm / s, using an ArF excimer laser immersion exposure apparatus (ASML's "XT1900i"). The exposure was performed at the scan speed of. Subsequently, after standing for 60 seconds during PIR (post-immersion rinse) after exposure, PEB was performed at 90 ° C. for 60 seconds. Then, it was subjected to alkaline development using a 2.38 mass% TMAH aqueous solution as an alkaline developer, washed with water, and dried to form a positive WM defect evaluation resist pattern. When forming this resist pattern, the optimum exposure amount is the exposure amount when the pattern formed through a 1: 1 line-and-space mask having a target dimension of 40 nm is formed in a 1: 1 line-and-space pattern having a line width of 40 nm. And said.

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

[Storage stability (1)]
For the radiation-sensitive resin composition immediately after preparation and the radiation-sensitive resin composition after storage at 25 ° C. for 3 months after preparation, a pattern formed through a 40 nm 1: 1 line-and-space mask has a line width. The exposure amount (optimum exposure amount) when formed in a one-to-one line and space of 40 nm was measured, and the optimum exposure amount of the radiation-sensitive resin composition immediately after preparation was Ea, and after storage for 3 months after preparation. The optimum exposure amount of the radiation-sensitive resin composition 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 poor when it is less than -1.00 or more than 1.00. ..

[Storage stability (2)]
Examples (J-1) to (J-24) and Comparative Examples (JJ-1) to (JJ-2) of the photoresist composition were stored at 35 ° C. for 3 months, and then the turbidity of the solution was visually observed. I confirmed it.

The evaluation results of the resist patterns (1) (ArF exposure, alkaline development) formed from Examples 1 to 24 and Comparative Examples 1 and 2 are shown in Table 4 below.

<Formation of resist pattern (3)> (electron beam exposure, alkaline 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 was blended and filtered through a solvent 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 to 4 were prepared in the same manner as in Example 25 except that the components of the types and blending amounts shown in Table 5 below were used.

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

<Evaluation of resist pattern (3) (electron beam exposure, alkaline development)>
By measuring the resist patterns formed in each of Examples 25 to 28 and Comparative Examples 3 to 4 (electron beam exposure, alkaline development) according to the following method, development defect suppression property can be achieved by the same method as in the case of ArF exposure. And storage stability (1) was evaluated. Further, as described above, as an evaluation of the storage stability (2), the radiation-sensitive resin compositions (J-30) to (J-33) and (JJ-3) to (JJ-4) were used at 35 ° C. for 3 months. After storage, the turbidity of the solution was visually confirmed.

The evaluation results of the resist patterns (3) (electron beam exposure, alkaline development) formed from Examples 25 to 28 and Comparative Examples 3 to 4 are shown in Table 6 below.

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

On the other hand, in Comparative Example 1 containing no fluorine atom in ArF exposure, all items were inferior, and in particular, WM defect suppression property and storage stability were extremely inferior. Further, in Comparative Example 2 containing 6 fluorine atoms, the WM defect suppressing property and the storage stability (2) were excellent, but the developing defect suppressing property and the storage stability (1) were very inferior. In Comparative Example 3 containing no fluorine atom in the electron beam exposure, the development defect suppressing property was excellent, but the storage stability (1) and (2) were very inferior. Further, in Comparative Example 4 containing 6 fluorine atoms, the storage stability (2) was excellent, but the development defect suppressing property was very inferior. Generally, it is known that electron beam exposure shows the same tendency as EUV exposure, and therefore, according to the radiation-sensitive resin composition of Examples, even in EUV exposure. It is presumed to be excellent in development defect suppression property, watermark defect suppression property, storage stability and the like.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern having excellent development defect suppressing property, watermark defect suppressing property, and storage stability can be formed. Therefore, these can be suitably used for pattern formation in semiconductor device manufacturing and the like, where further miniaturization is expected to progress.

Claims (8)

An acid diffusion control agent containing a compound having an anion represented by the following formula (1).

(In the formula (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 is a '.G are each independently an oxygen atom or a sulfur atom .R ^X are each independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x is Together with -G-C-G- which are combined with each other and bonded to 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 independent of each other. 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 constitute a ring structure composed of ring members 3 to 20 together with the carbon atom bonded these aligned with each other. However, when R ¹ to R ⁴ is a monovalent organic group, R ¹ to R ⁴ is It does not contain a fluorine atom. R ^f1 and R ^f2 are independently fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 4 carbon atoms.) The acid diffusion control agent according to claim 1, wherein the compound is represented by the following formula (2).

(In the formula (2), X, ^RX , R ¹ , R ² , R ³ , R ⁴ , Y, Y', R ^f1 and R ^f2 are synonymous with the above formula (1). Z ⁺ is synonymous with the above formula (1). It is a monovalent cation.) X in the above formula (1) and the above formula (2) is -C (= O) Y, -C (= O) OY, -C (GR ^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' , R ¹ , R ² , R ³ and R ⁴ are independent hydrogen 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 is an acid diffusion control according to claim 1 or claim 2 represents an alicyclic structure or aliphatic heterocyclic structure consisting ring members 3 to 20 together with the carbon atom bonded these aligned with one another Agent. The acid diffusion control agent according to claim 1, claim 2 or claim 3, wherein ^{R f1} and R ^f2 in the above formula (1) and the above formula (2) are fluorine atoms. A compound having an anion represented by the following formula (1).

(In the formula (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 is a '.G are each independently an oxygen atom or a sulfur atom .R ^X are each independently a monovalent organic group having 1 to 20 carbon atoms, or two R ^x is Together with -G-C-G- which are combined with each other and bonded to 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 independent of each other. 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 constitute a ring structure composed of ring members 3 to 20 together with the carbon atom bonded these aligned with each other. However, when R ¹ to R ⁴ is a monovalent organic group, R ¹ to R ⁴ is It does not contain a fluorine atom. R ^f1 and R ^f2 are independently fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 4 carbon atoms.) The compound according to claim 5, wherein the compound is represented by the following formula (2).

(In the formula (2), X, ^RX , R ¹ , R ² , R ³ , R ⁴ , Y, Y', R ^f1 and R ^f2 are synonymous with the above formula (1). Z ⁺ is synonymous with the above formula (1). It is a monovalent cation.) X in the above formula (1) and the above formula (2) is -C (= O) Y, -C (= O) OY, -C (GR ^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' , R ¹ , R ² , R ³ and R ⁴ are independent hydrogen 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 is a compound according to claim 5 or claim 6 represents an alicyclic structure or aliphatic heterocyclic structure consisting ring members 3 to 20 together with the carbon atom bonded these aligned with each other. The compound according to claim 5, claim 6 or claim 7, wherein ^{R f1} and R ^f2 in the above formula (1) and the above formula (2) are fluorine atoms.