JP6443000B2 - Radiation sensitive resin composition - Google Patents

Description

  The present invention relates to a radiation sensitive resin composition, a polymer, and a compound.

  The chemically amplified radiation-sensitive resin composition is applied to the exposed portion by irradiation (exposure) such as far ultraviolet rays and electron beams represented by KrF excimer laser light (wavelength 248 nm) and ArF excimer laser light (wavelength 193 nm). An acid is generated, and a chemical reaction using the acid as a catalyst causes a difference in the dissolution rate of the exposed portion and the unexposed portion with respect to the developer, thereby forming a resist pattern on the substrate.

  As a radiation sensitive resin composition using an ArF excimer laser as a light source, for example, a composition containing a polymer having an alicyclic hydrocarbon having no absorption in a 193 nm region in a skeleton is known. According to this, the development contrast is improved. As the polymer, a polymer containing a structural unit having a spirolactone structure has been proposed (see JP 2005-002248 A).

  However, when the conventional radiation-sensitive resin composition is used for organic solvent development, the polymer may remain undissolved at the time of development, and LWR performance (a value representing variation in the line width of the resist pattern to be formed ( (Line Width Roughness), resolution, rectangularity of the cross-sectional shape of the resist pattern, depth of focus, and the like cannot be sufficiently satisfied. Further, the conventional radiation-sensitive resin composition cannot sufficiently satisfy the LWR performance, the resolution, the rectangular shape of the cross-sectional shape of the resist pattern, the depth of focus, and the like even when used for alkaline aqueous solution development. In addition, the conventional radiation-sensitive resin composition has a problem that the film shrinkage is large during post-exposure baking (PEB) after exposure as a resist film. Furthermore, the conventional radiation sensitive resin composition has the problem that the defect derived from a radiation sensitive resin composition generate | occur | produces at the time of pattern formation.

JP-A-2005-002248

  The present invention has been made on the basis of the circumstances as described above, and the purpose thereof is LWR performance, resolution, rectangularity of a cross-sectional shape, depth of focus, resist film shrinkage restraint, and defect occurrence restraint (hereinafter referred to as the following). , Also referred to as “LWR performance and the like”).

  The invention made in order to solve the above-mentioned problem is a polymer having a first structural unit represented by the following formula (1) (hereinafter also referred to as “structural unit (I)”) (hereinafter referred to as “[A] And a radiation-sensitive resin composition containing a radiation-sensitive acid generator (hereinafter also referred to as [B] acid generator).

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^{2 to} R ⁶ are each independently a hydrogen atom or a monovalent group having 1 to 20 carbon atoms. A is an integer of 1 to 5. When a is 2 or more, the plurality of R ⁵ may be the same or different, and the plurality of R ⁶ may be the same or different. However, at least one of the one or more R ⁵ and the one or more R ⁶ is the monovalent organic group, L is a divalent organic group having 1 to 20 carbon atoms. , R ² and R ³ are both hydrogen atoms, R ⁴ is the above-mentioned monovalent organic group, and two or more of R ⁴ , L, one or more R ⁵ and one or more R ⁶ are Even if they form a ring structure having 3 to 20 carbon atoms that is configured together with the carbon atoms or atomic chains to which they are bonded together There If .R ² is the monovalent organic group and ^{R 3} is a hydrogen ^atom, these two or more of R 4, L, 1 or more ^{R 5} and one or more ^{R 6} are combined with each other A ring structure having 3 to 20 carbon atoms configured with a carbon atom or an atomic chain to be bonded may be formed, and ^two of R ² , L, one or more R ⁵ and one or more R ⁶ above are combined with each other when these carbon atoms or a chain of atoms with configured organic group ring structure are both good .R ² and R ³ be formed above monovalent 3 to 20 carbon atoms that bond, R ² , R ³ , R ⁴ , L, one or more of R ⁵ and one or more of R ⁶ are combined with each other, and the number of carbon atoms is 3 to 3 together with the carbon atom or atomic chain to which they are bonded 20 ring structures may be formed.)

  The polymer of the present invention has a structural unit (I) represented by the following formula (1).

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^{2 to} R ⁶ are each independently a hydrogen atom or a monovalent group having 1 to 20 carbon atoms. A is an integer of 1 to 5. When a is 2 or more, the plurality of R ⁵ may be the same or different, and the plurality of R ⁶ may be the same or different. However, at least one of the one or more R ⁵ and the one or more R ⁶ is the monovalent organic group, L is a divalent organic group having 1 to 20 carbon atoms. , R ² and R ³ are both hydrogen atoms, R ⁴ is the above-mentioned monovalent organic group, and two or more of R ⁴ , L, one or more R ⁵ and one or more R ⁶ are Even if they form a ring structure having 3 to 20 carbon atoms that is configured together with the carbon atoms or atomic chains to which they are bonded together There If .R ² is the monovalent organic group and ^{R 3} is a hydrogen ^atom, these two or more of R 4, L, 1 or more ^{R 5} and one or more ^{R 6} are combined with each other A ring structure having 3 to 20 carbon atoms configured with a carbon atom or an atomic chain to be bonded may be formed, and ^two of R ² , L, one or more R ⁵ and one or more R ⁶ The above may be combined with each other to form a ring structure having 3 to 20 carbon atoms that is configured together with a carbon atom or an atomic chain to which they are bonded, and when R ² and R ³ are both the above monovalent organic groups, R ² , R ³ , R ⁴ , L, one or more of R ⁵ and one or more of R ⁶ are combined with each other, and the number of carbon atoms is 3 to 3 together with the carbon atom or atomic chain to which they are bonded 20 ring structures may be formed.)

  The compound of the present invention is a compound represented by the following formula (i) (hereinafter also referred to as “compound (i)”).

(In formula (i), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^{2 to} R ⁶ are each independently a hydrogen atom or a monovalent group having 1 to 20 carbon atoms. A is an integer of 1 to 5. When a is 2 or more, the plurality of R ⁵ may be the same or different, and the plurality of R ⁶ may be the same or different. However, at least one of the one or more R ⁵ and the one or more R ⁶ is the monovalent organic group, L is a divalent organic group having 1 to 20 carbon atoms. , R ² and R ³ are both hydrogen atoms, R ⁴ is the above-mentioned monovalent organic group, and two or more of R ⁴ , L, one or more R ⁵ and one or more R ⁶ are Even if they form a ring structure having 3 to 20 carbon atoms that is configured together with the carbon atoms or atomic chains to which they are bonded together There If .R ² is the monovalent organic group and ^{R 3} is a hydrogen ^atom, these two or more of R 4, L, 1 or more ^{R 5} and one or more ^{R 6} are combined with each other A ring structure having 3 to 20 carbon atoms configured with a carbon atom or an atomic chain to be bonded may be formed, and ^two of R ² , L, one or more R ⁵ and one or more R ⁶ The above may be combined with each other to form a ring structure having 3 to 20 carbon atoms that is configured together with a carbon atom or an atomic chain to which they are bonded, and when R ² and R ³ are both the above monovalent organic groups, R ² , R ³ , R ⁴ , L, one or more of R ⁵ and one or more of R ⁶ are combined with each other, and the number of carbon atoms is 3 to 3 together with the carbon atom or atomic chain to which they are bonded 20 ring structures may be formed.)

  According to the radiation-sensitive resin composition of the present invention, a resist pattern that exhibits excellent depth of focus and resist film shrinkage suppression, low LWR, high resolution, excellent cross-sectional rectangularity, and few defects. Can be formed. The polymer of this invention can be used suitably as a polymer component of the said radiation sensitive resin composition. The compound of the present invention can be suitably used as a raw material monomer for the polymer. Therefore, these can be suitably used in a lithography process that requires further miniaturization.

<Radiation sensitive resin composition>
The radiation sensitive resin composition of the present invention contains a [A] polymer and a [B] acid generator. Moreover, the said radiation sensitive resin composition is a polymer (henceforth "[[C] solvent, [D] acid diffusion control body, and a polymer with a higher fluorine atom content than [E] [A] polymer (henceforth" [ E] polymer ”. Furthermore, the said radiation sensitive resin composition may contain another arbitrary component, unless the effect of this invention is impaired. Hereinafter, each component will be described in detail.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I) represented by the above formula (1). [A] The polymer preferably further has a structural unit (II) which is a structural unit other than the structural unit (I) and contains an acid dissociable group. [A] The polymer is a structural unit other than the structural unit (I) and the structural unit (II) and includes at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. You may have unit (III). Furthermore, the polymer [A] may have other structural units other than the structural unit (I), the structural unit (II) and the structural unit (III) as long as the effects of the present invention are not impaired. In addition, the [A] polymer may have 2 or more types of each structural unit. Hereinafter, each structural unit will be described in detail.

[Structural unit (I)]
The structural unit (I) is a structural unit represented by the above formula (1). At least one organic group is bonded to the lactone ring of the structural unit (I), and it is considered that the hydrophobicity of the [A] polymer is high. As a result, the radiation sensitive resin composition is LWR performance and the like can be improved. The reason why the radiation-sensitive resin composition exhibits the above-described effect by having the above-described configuration is not necessarily clear, but for example, at least one organic group is bonded to the lactone ring of the structural unit (I). Thus, in the case of organic solvent development, the affinity between the [A] polymer and the organic solvent is effectively improved, and in the case of alkali development, the solubility of the [A] polymer in an aqueous alkali solution is reduced. In addition, it is conceivable that the unexposed portion of the resist film to be formed can be effectively prevented from dissolving in the alkaline aqueous solution. Moreover, since the structural unit (I) has a lactone ring, the adhesion of the resist film to the substrate can be improved.

In said formula (1), R < ¹ > is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^{2 to} R ⁶ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. a is an integer of 1-5. When a is 2 or more, the plurality of R ⁵ may be the same or different, and the plurality of R ⁶ may be the same or different. However, at least one of the one or more R ⁵ and the one or more R ⁶ is the monovalent organic group. L is a C1-C20 divalent organic group. However, when both R ² and R ³ are hydrogen atoms, R ⁴ is the above monovalent organic group, and two or more of R ⁴ , L, one or a plurality of R ⁵ and one or a plurality of R ⁶ May be combined with each other to form a ring structure of 3 to 20 carbon atoms configured with a carbon atom or an atomic chain to which they are bonded. When R ² is a monovalent organic group and R ³ is a hydrogen atom, two or more of R ⁴ , L, one or more R ⁵ and one or more R ⁶ are combined with each other and bonded together. A ring structure having 3 to 20 carbon atoms configured with a carbon atom or an atomic chain may be formed, and ^two or more of R ² , L, one or more R ⁵ and one or more R ⁶ may be You may form the C3-C20 ring structure comprised with the carbon atom or atomic chain which these are match | combined and these couple | bond together. When R ² and R ³ are both monovalent organic groups, ^two or more of R ² , R ³ , R ⁴ , L, one or more R ⁵ and one or more R ⁶ are combined with each other. You may form the C3-C20 ring structure comprised with the carbon atom or atomic chain which these couple | bond.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^{2 to} R ⁶ include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent fat having 3 to 20 carbon atoms. A monovalent hetero group including a cyclic hydrocarbon group, a monovalent hydrocarbon group such as a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a group having a hetero atom between carbon and carbon of the hydrocarbon group. Examples thereof include monovalent groups in which part or all of the hydrogen atoms of the atom-containing group, the hydrocarbon group, and the heteroatom-containing group are substituted with a substituent.

Examples of the chain hydrocarbon group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, and n-pentyl group. Alkyl groups such as
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group, butynyl group, and pentynyl group.

Examples of the alicyclic hydrocarbon group include monocyclic cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group;
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group and a tricyclodecyl group;
A monocyclic cycloalkenyl group such as a cyclopentenyl group and a cyclohexenyl group;
Examples thereof include polycyclic cycloalkenyl groups such as norbornenyl group and tricyclodecenyl group.

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

  The hetero atom of the group having a hetero atom is an atom other than a carbon atom and a hydrogen atom, for example, an oxygen atom, a nitrogen atom, a silicon atom, a phosphorus atom, a sulfur atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom. And halogen atoms such as

Examples of the group having a heteroatom include —O—, —NR′—, —S—, —CO—, —CS—, —SO ₂ —, and a combination thereof. R ′ is a monovalent hydrocarbon group having 1 to 10 carbon atoms.

  Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, Examples include an acyloxy group, and an oxygen atom (═O, oxy group) that replaces two hydrogen atoms bonded to the same carbon atom.

  As a, 2 or 3 is preferable.

  Examples of the divalent organic group having 1 to 20 carbon atoms represented by L include a divalent chain hydrocarbon group having 1 to 20 carbon atoms and a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. A divalent heteroatom-containing group containing a divalent hydrocarbon group such as a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group having a heteroatom between carbon-carbons of the hydrocarbon group, And divalent groups in which part or all of the hydrogen atoms of the hydrocarbon group and heteroatom-containing group are substituted with a substituent.

Specific examples thereof include a divalent group obtained by removing one hydrogen atom from those exemplified as the monovalent organic group having 1 to 20 carbon atoms represented by R ^{2 to} R ^6. .

R ⁴ , L, two or more of one or more R ⁵ and one or more R ⁶ , R ² , L, one or more R ⁵ and two or more of one or more R ⁶ , And a ring structure having 3 to 20 carbon atoms formed by two or more of R ² , R ³ , R ⁴ , L, one or more R ⁵ and one or more R ⁶ , a cycloheptane ring structure , Cyclohexane ring structure, norbornane ring structure, adamantane ring structure, benzene ring structure and the like.

  Examples of the structural unit (I) include structural units represented by the following formulas (1-1) to (1-17).

In the above formula, ^{R 1} has the same meaning as in the formula (1).

  [A] The lower limit of the content ratio of the structural unit (I) in the polymer is preferably 1 mol%, more preferably 3 mol%, more preferably 5 mol% with respect to all the structural units constituting the [A] polymer. Is more preferable. As an upper limit of the said content rate, 80 mol% is preferable, 50 mol% is more preferable, and 25 mol% is further more preferable. By making the content rate of structural unit (I) into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved more.

<Method for Producing Compound (i)>
[A] As described later, the polymer [A] can be obtained by radical polymerization of the monomer that gives the structural unit (I) together with a monomer that gives another structural unit as necessary. The compound (i) that gives the structural unit (I) can be produced, for example, by subjecting a compound represented by the following formula (a) and a compound represented by the following formula (b) to an esterification reaction. .

In said formula (a) and (b), R < ¹ >, R < ² > -R < ⁶ >, a and L are synonymous with Formula (1).

  The compound represented by the following formula (b) can be synthesized according to a known method.

[Structural unit (II)]
The structural unit (II) is a structural unit containing an acid dissociable group. Since the structural unit (I) may be an acid dissociable group, the structural unit (II) is a structural unit other than the structural unit (I). In the exposed part, the acid-dissociable group in the structural unit (II) is dissociated by the action of the acid generated from the [B] acid generator in the exposed portion, whereby the development of the [A] polymer is performed. Since the solubility in the liquid changes, the resist pattern can be formed with high sensitivity. As a result, the radiation sensitive resin composition can further improve the LWR performance and the like. The “acid-dissociable group” in the structural unit (II) refers to a group that replaces a hydrogen atom of a polar group such as a carboxy group or a hydroxy group, and dissociates in the presence of an acid. The structural unit (II) is not particularly limited as long as it contains an acid dissociable group, and examples thereof include a structural unit represented by the following formula (2).

In the formula (2), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^p is a monovalent acid dissociable group.

The monovalent acid dissociable group represented by R ^p is preferably a group represented by the following formula (I).

In said formula (I), R ^<p1> is a C1-C20 monovalent hydrocarbon group. R ^p2 and R ^p3 are each independently a monovalent chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are An alicyclic structure having 3 to 20 ring members composed of carbon atoms bonded to each other and bonded thereto is represented.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^p1 include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent alicyclic group having 3 to 20 carbon atoms. Examples include hydrocarbon groups and monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms represented by R ^p1 , R ^p2 and R ^p3 include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and n-butyl. Group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^p1 , R ^p2 and R ^p3 include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclo Cycloalkyl groups such as octyl, cyclodecyl, cyclododecyl, norbornyl, adamantyl, tricyclodecyl, tetracyclododecyl;
And cycloalkenyl groups such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group, a cyclooctenyl group, a cyclodecenyl group, a norbornenyl group, a tricyclodecenyl group, and a tetracyclododecenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by R ^p1 , R ^p2 and R ^p3 include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group and anthryl group;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, and naphthylmethyl group.

Among these, R ^p1 is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, and R ^ap group and cycloalkane constituted by carbon atoms to which R ^p2 and R ^p3 groups are combined and bonded to each other It is preferable to represent the structure.

  Examples of the structural unit (II) include structural units represented by the following formulas (2-1) to (2-4).

In the above formulas (2-1) to (2-4), R ⁷ has the same meaning as the above formula (1). R ^p1 , R ^p2 and R ^p3 are as defined in the above formula (I). n _p is an integer of 1 to 4.

  Examples of the structural unit represented by the above formula (2) or (2-1) to (2-4) include a structural unit represented by the following formula.

In said formula, R < ⁷ > is synonymous with the said Formula (2).

  Examples of the monomer that gives structural unit (II) include (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyladamantyl-2-yl ester, (meth) acrylic acid- 2-methylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid 1- ( Bicyclo [2.2.1] hept-2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1-methyl -1-cyclopentyl ester, (meth) acrylic acid 1-ethyl-1-cyclopentyl ester, (meth) acrylic acid 1-methyl-1-cyclohexyl ester, ( Data), and acrylic acid 1-ethyl-1-cyclohexyl ester.

  [A] As a minimum of the content rate of structural unit (II) in a polymer, 15 mol% is preferred to 25 mol% with respect to all the structural units which constitute [A] polymer. As an upper limit of the said content rate, 80 mol% is preferable and 50 mol% is more preferable. By setting it as such a content rate, the sensitivity of the said radiation sensitive resin composition can be improved, As a result, LWR performance etc. can be improved more.

[Structural unit (III)]
The structural unit (III) is a structural unit other than the structural unit (I) and the structural unit (II), and includes at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. It is. [A] When the polymer further includes the structural unit (III), adhesion of the resist film to the substrate can be enhanced.

  As structural unit (III), the structural unit represented, for example by a following formula is mentioned.

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

  [A] The content ratio of the structural unit (III) in the polymer is preferably 0 mol% or more and 60 mol% or less with respect to all the structural units constituting the [A] polymer. The adhesiveness of a resist film can be improved more by making the content rate of structural unit (III) into the said range.

<Other structural units>
[A] The polymer may have a structural unit other than the above. Examples of the polymerizable unsaturated monomer that gives other structural units include monomers disclosed in paragraphs [0065] to [0085] of International Publication No. 2007/116664.

  The other structural unit is preferably a structural unit derived from 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate or 3-hydroxypropyl (meth) acrylate.

  [A] The content of other structural units in the polymer is usually 30 mol% or less, preferably 20 mol% or less, and preferably 10 mol% or less, based on all structural units constituting the [A] polymer. Is more preferable.

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

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized according to a conventional method such as radical polymerization. Examples of the synthesis method include a method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction; a solution containing the monomer and a radical initiator A solution containing each of the monomers separately added to a reaction solvent or a solution containing a monomer to cause a polymerization reaction; a plurality of types of solutions containing each monomer; and a solution containing a radical initiator And a method of dropping them into a reaction solvent or a monomer-containing solution to cause a polymerization reaction.

  The reaction temperature in the polymerization is appropriately determined depending on the radical initiator species, but the lower limit of the reaction temperature is usually 30 ° C, preferably 40 ° C, more preferably 50 ° C. As an upper limit of reaction temperature, it is 180 degreeC normally, 160 degreeC is preferable and 140 degreeC is more preferable. The dropping time varies depending on the reaction temperature, the type of radical initiator, the monomer to be reacted, etc., but the lower limit of the dropping time is usually 30 minutes, preferably 45 minutes, and more preferably 1 hour. The upper limit of the dropping time is usually 8 hours, preferably 6 hours, and more preferably 5 hours. Moreover, as a minimum of the total reaction time including dripping time, it is 30 minutes normally, 45 minutes are preferable and 1 hour is more preferable. The upper limit of the total reaction time is usually 8 hours, preferably 7 hours, and more preferably 6 hours.

  Examples of the radical initiator include 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis ( 2-cyclopropylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2-azobisisobutyrate and the like. These radical initiators can be used in combination of two or more.

  The solvent used for the polymerization is not limited as long as it is a solvent other than a solvent that inhibits polymerization of each monomer and can dissolve the monomer. Examples of the solvent include alcohol solvents, ketone solvents, amide solvents, ester solvents, lactone solvents, nitrile solvents, and the like. Two or more of these solvents can be used in combination.

  The polymer obtained by the polymerization reaction can be recovered by a reprecipitation method. As the reprecipitation solvent, an alcohol solvent or the like can be used.

  [A] In the polymerization reaction for synthesizing the polymer, a molecular weight modifier can be used to adjust the molecular weight. Examples of the molecular weight modifier include halogenated hydrocarbons such as chloroform and carbon tetrabromide; mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and thioglycolic acid; Xanthogens such as xanthogen sulfide and diisopropylxanthogen disulfide; terpinolene, α-methylstyrene dimer and the like.

  [A] As a minimum of polystyrene conversion weight average molecular weight (Mw) by gel permeation chromatography (GPC) of a polymer, 1,000 is preferred and 2,000 is more preferred. The upper limit of Mw is preferably 20,000, and more preferably 10,000. [A] By making Mw of a polymer into the said range, lithography performance, such as the sensitivity of the said radiation sensitive resin composition, and LWR performance, can further be improved.

  [A] The content of the low molecular weight component in the polymer is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.06% by mass or less. By setting the content of the low molecular weight component in the above range, the development contrast can be further improved. In addition, a low molecular weight component means a thing with a molecular weight less than 1,000.

  [A] The ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is usually from 1 to 5, preferably from 1 to 3, and more preferably from 1 to 2. In addition, Mw and Mn of the polymer in this specification are measured by GPC under the following conditions.

Column: 2 G2000HXL, 1 G3000HXL, and 1 G4000HXL (Tosoh Corporation)
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

<[B] Acid generator>
[B] The acid generator is a radiation-sensitive acid generator. [B] The acid generator generates an acid by exposure, and the acid dissociates an acid dissociable group or the like of the structural unit (II) of the polymer [A] to generate a carboxy group or the like. As a result, the polarity of the [A] polymer increases, and the [A] polymer in the exposed area becomes soluble in the developer in the case of alkaline aqueous solution development, while in the case of organic solvent development, It becomes sparingly soluble. The contained form of the [B] radiation-sensitive acid generator in the radiation-sensitive resin composition may be a compound form as described later (hereinafter also referred to as “[B] acid generator”). It may be a form incorporated as a part or both of these forms.

  [B] Examples of the acid generator include onium salt compounds, sulfonimide compounds, halogen-containing compounds, diazoketone compounds, and the like.

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

  Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2- (1-adamantyl) -1,1-difluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenyl Sulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro-n-octanesulfonate 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4- Methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl -1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-6- (1-adamantanecarbonyloxy) -hexane-1-sulfur Sulfonates, and the like.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona. Fluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophene Nitro 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium trifluoromethane Sulfonate, 1- (6-n-butoxynaphthalene-2 Yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalene- 2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydro Thiophenium perfluoro-n-octance Phonates, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, etc. Can be mentioned.

  Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t -Butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetra Le Oro ethanesulfonate.

  Examples of the sulfonimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy) bicyclo [ 2.2.1] Hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3- Dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene -2,3-dicarboximide and the like.

  Of these [B] acid generators, sulfonium salts are preferable, and triphenylsulfonium 2- (1-adamantyl) -1,1-difluoroethanesulfonate is more preferable.

  These [B] acid generators can use 2 or more types together. [B] The lower limit of the content when the acid generator is an acid generator is usually 0.1 with respect to 100 parts by mass of the polymer [A] from the viewpoint of ensuring sensitivity and developability as a resist. 1 part by mass is preferable, and 3 parts by mass is more preferable. The upper limit of the content is usually 30 parts by mass, preferably 25 parts by mass, and more preferably 20 parts by mass. [B] When the content of the acid generator is less than the lower limit, the sensitivity and developability of the radiation-sensitive resin composition tend to decrease. On the other hand, when the content of the [B] acid generator exceeds the above upper limit, the transparency to exposure light is lowered, and it may be difficult to obtain a desired resist pattern.

<[C] solvent>
The radiation-sensitive resin composition usually contains a [C] solvent. [C] As the solvent, a solvent in which each component is uniformly dissolved or dispersed and does not react with each component is preferably used. [C] Examples of the solvent include alcohols, ethers, ketones, amides, esters, hydrocarbons and the like. In addition, these solvents can use 2 or more types together.

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

Examples of the ether solvent include dialiphatic ethers such as diethyl ether, dipropyl ether, and dibutyl ether;
Diaromatic ethers such as diphenyl ether and ditolyl ether;
Examples thereof include aromatic-aliphatic ethers such as anisole and phenylethyl 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, methyl amyl ketone, ethyl-n-butyl ketone, and methyl-n-hexyl ketone. Aliphatic ketone solvents such as di-iso-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone;
Aliphatic-aromatic ketone solvents such as acetophenone, propiophenone, tolylmethylketone;
Aromatic ketone solvents such as benzophenone, tolylphenyl ketone, and ditolyl ketone are listed.

Examples of the amide solvents include N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide. , N-methylpropionamide, N-methylpyrrolidone and the like.

Examples of the ester solvent include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, and acetic acid. 3-methoxybutyl, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, methoxytriglycol acetate, ethyl propionate Monoester solvents such as n-butyl propionate, iso-amyl propionate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate;
Diester solvents such as glycol diacetate, diethyl oxalate, di-n-butyl oxalate, diethyl malonate, dimethyl phthalate and diethyl phthalate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Polyhydric alcohol monoether acetate solvents such as acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
Lactone solvents such as γ-butyrolactone and γ-valerolactone;
Examples thereof include carbonate solvents such as diethyl carbonate, dipropyl carbonate, ethylene carbonate, and propylene carbonate.

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

  Of these, esters and ketones are preferable, and propylene glycol monomethyl ether acetate and cyclohexanone are more preferable.

<[D] Acid diffusion controller>
The radiation sensitive resin composition preferably contains a [D] acid diffusion controller. [D] The acid diffusion controller controls the diffusion phenomenon in the resist film of the acid generated from the [B] acid generator by exposure, and has an effect of suppressing an undesirable chemical reaction in the non-exposed region. When the radiation-sensitive resin composition further contains a [D] acid diffusion controller, the radiation-sensitive resin composition can form a resist pattern that is superior in pattern developability and LWR performance. The content of the [D] acid diffusion controller in the radiation-sensitive resin composition is a part of the polymer even in the form of a compound as described later (hereinafter also referred to as “[D] acid diffusion controller” as appropriate). Or may be both of these forms.

  [D] Examples of the acid diffusion controller include amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

  Examples of the amine compound include mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N, N ′, N′-tetra Methylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4 -Aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-amino) Phenyl) -2- (4-hydroxyphenyl) propane, 1, -Bis (1- (4-aminophenyl) -1-methylethyl) benzene, 1,3-bis (1- (4-aminophenyl) -1-methylethyl) benzene, bis (2-dimethylaminoethyl) ether Bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ′ , N ″, N ″ -pentamethyldiethylenetriamine and the like.

  Examples of amide group-containing compounds include Nt-butoxycarbonyl group-containing amino compounds such as N- (t-butoxycarbonyl) -4-hydroxypiperidine, and N- (t-pentyloxycarbonyl) -4-hydroxypiperidine. Nt-pentyloxycarbonyl group-containing amino compound, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methyl Examples include pyrrolidone, N-acetyl-1-adamantylamine, and isocyanuric acid tris (2-hydroxyethyl).

  Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea and the like. Is mentioned.

  Examples of the nitrogen-containing heterocyclic compound include imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinazoline, purine, pyrrolidine, piperidine, piperidineethanol, 2-quinoxalinol, 3-piperidino-1,2-propane. Diol, morpholine, 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane and the like.

  [D] As the acid diffusion control agent, a photodegradable base that is sensitized by exposure and generates a weak acid can also be used. An example of a photo-disintegrating base includes an onium salt compound that decomposes upon exposure and loses acid diffusion controllability. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (K1) and an iodonium salt compound represented by the following formula (K2).

In the above formulas (K1) and (K2), R ^{8 to} R ¹² are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, or a halogen atom. Z ^- and ^E - ^{are, OH -, R A -COO -} , R A -SO 3 -, R A -N - is an anion represented by _-SO 2 -R ^B or formula (K3). However, ^RA is an alkyl group, an aryl group, or an alkaryl group. R ^B is an alkyl group which may have a fluorine atom.

In the above formula (K3), R ¹³ is a linear or branched alkyl group having 1 to 12 carbon atoms in which part or all of the hydrogen atoms may be substituted with fluorine atoms, or 1 to 12 carbon atoms. These are linear or branched alkoxy groups. u is an integer of 0-2.

  [D] Two or more acid diffusion control agents may be used in combination. [D] The lower limit of the content when the acid diffusion controller is a [D] acid diffusion controller is preferably 0.1 parts by mass and 0.5 parts by mass with respect to 100 parts by mass of the polymer [A]. Part is more preferred. As an upper limit of the said content, 20 mass parts is preferable and 15 mass parts is more preferable. [D] By making content of an acid diffusion control agent into the said range, the LWR performance of the said radiation sensitive resin composition etc. improve more.

[[E] polymer]
The [E] polymer is a polymer having a higher fluorine atom content than the [A] polymer. When the resist material contains the [E] polymer, the distribution tends to be unevenly distributed on the surface of the resist film due to the oil-repellent characteristics of the [E] polymer when the resist film is formed. As a result, when performing immersion exposure, it can suppress that an acid generator, an acid diffusion control agent, etc. elute to an immersion medium, and is preferable. Further, due to the water-repellent characteristics of the [E] polymer, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range, and the occurrence of bubble defects can be suppressed. Furthermore, the receding contact angle between the resist film and the immersion medium is increased, and high-speed scanning exposure is possible without leaving water droplets. In addition, a fluorine atom content rate (mass%) can be calculated | required by calculating | requiring the structure of a polymer by measuring ¹³ C-NMR, ¹ H-NMR, IR spectrum, etc.

  [E] The polymer is not particularly limited as long as the fluorine atom content is higher than that of the [A] polymer, but preferably has a fluorinated alkyl group. [E] The polymer is formed by polymerization using at least one monomer containing a fluorine atom in the structure. Monomers that contain fluorine atoms in the structure include monomers that contain fluorine atoms in the main chain, monomers that contain fluorine atoms in the side chain, and monomers that contain fluorine atoms in the main chain and side chains. Can be mentioned.

  Examples of the monomer containing a fluorine atom in the main chain include an α-fluoroacrylate compound, an α-trifluoromethyl acrylate compound, a β-fluoroacrylate compound, a β-trifluoromethyl acrylate compound, an α, β-fluoroacrylate compound, An α, β-trifluoromethyl acrylate compound, a compound in which a hydrogen atom of one or more kinds of vinyl sites is substituted with a fluorine atom or a trifluoromethyl group, and the like can be mentioned.

  Examples of the monomer containing a fluorine atom in the side chain include those in which the side chain of an alicyclic olefin compound such as norbornene is a fluorine atom or a fluoroalkyl group or a derivative thereof, a fluoroalkyl group of acrylic acid or methacrylic acid, or Examples thereof include an ester compound having such a derivative group, a monomer in which the side chain of one or more olefins (site not including a double bond) is a fluorine atom, a fluoroalkyl group or a derivative group thereof.

  Examples of monomers containing fluorine atoms in the main chain and the side chain include α-fluoroacrylic acid, β-fluoroacrylic acid, α, β-fluoroacrylic acid, α-trifluoromethylacrylic acid, β-trifluoro. An ester compound having a fluoroalkyl group such as methylacrylic acid or α, β-trifluoromethylacrylic acid or a derivative group thereof, a compound in which hydrogen atoms of one or more kinds of vinyl sites are substituted with a fluorine atom or a trifluoromethyl group Monomer substituted with a fluorine atom or a fluoroalkyl group or a derivative thereof, a hydrogen atom bonded to a double bond of one or more alicyclic olefin compounds, a fluorine atom or a trifluoromethyl group, etc. And a monomer whose side chain is a fluoroalkyl group or a derivative group thereof. In addition, this alicyclic olefin compound shows the compound in which a part of ring is a double bond.

  [E] As an aspect in which the polymer has a fluorine atom, the polymer preferably contains a structural unit (IV) represented by the following formula (F1).

In the above formula (F1), R ¹⁴ represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁵ is a linear or branched alkyl group having 1 to 6 carbon atoms having at least one fluorine atom, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof. k is an integer of 1 to 3. However, when R ¹⁵ is plural, plural R ¹⁵ may be different even in the same it. A is a single bond or a (k + 1) -valent linking group.

  As the (k + 1) -valent linking group represented by A, for example, an oxygen atom, a sulfur atom, a carbonyloxy group, an oxycarbonyl group, an amide group, a sulfonylamide group, a urethane group, carbonyloxy-di (oxycarbonyl) ethanediyl Group, carbonyloxy-di (oxycarbonyl) propanediyl group, tri (carbonyloxy) ethanediyl group, carbonyloxy-tri (oxycarbonyl) ethanediyl group, carbonyloxy-tri (oxycarbonyl) propanediyl group, tetra (carbonyloxy) And an ethanediyl group.

  Monomers that give the structural unit (IV) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, Fluoro n-propyl (meth) acrylate, perfluoro i-propyl (meth) acrylate, perfluoro n-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, perfluoro t -Butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylic acid ester, 1- (2,2,3,3,4,4, 5,5-octafluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic acid Stell, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, 1- (3,3,4,4,5,5,6,6,7,7,8 , 8,9,9,10,10,10-heptadecafluorodecyl) (meth) acrylic acid ester, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6- Octafluorohexyl) (meth) acrylic acid ester, 2,2-di (2,2,2-trifluoroethyloxycarbonyl) ethyl (meth) acrylic acid ester and 2,2-di (2,2,2-triic acid) Fluoroethyloxycarbonyl) ethyl (meth) acrylate is preferred, 2,2,2-trifluoroethyl (meth) acrylate and 2,2-di (2,2,2-trifluoroethyloxycarbonyl) ethyl (Me ) Acrylic acid ester are more preferable.

  [E] The polymer may have two or more structural units (IV). As a content rate of structural unit (IV), it is 5 mol% or more normally with respect to all the structural units in a [E] polymer, 10 mol% or more is preferable and 15 mol% or more is more preferable. If the content ratio of the structural unit (IV) is less than 5 mol%, a receding contact angle of 70 ° or more may not be achieved, and elution of an acid generator or the like from the resist film may not be suppressed.

  [E] In addition to the structural unit (IV), the polymer [E] contains an acid-dissociable group in order to control the dissolution rate in the developer, the structural unit (II) in the polymer, a lactone structure, and a cyclic structure. 1 or more types of other structural units, such as structural unit (III) in the said [A] polymer containing the at least 1 sort (s) chosen from the group which consists of a carbonate structure and a sultone structure, a structural unit containing an alicyclic hydrocarbon group, etc. can do.

  Examples of the structural unit containing the alicyclic hydrocarbon group include a structural unit represented by the following formula (F2).

In the above formula (F2), R ¹⁶ represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. X is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms.

Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by X include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, and bicyclo [2.2.2]. Octane, tricyclo [5.2.1.0 ^2,6 ] decane, tetracyclo [6.2.1.1 ^3,6 . And hydrocarbon groups composed of alicyclic rings derived from cycloalkanes such as 0 ^2,7 ] dodecane and tricyclo [3.3.1.1 ^3,7 ] decane.

  As a content rate of said other structural unit, it is 90 mol% or less normally with respect to all the structural units which comprise a [E] polymer, and 80 mol% or less is preferable.

  [E] As a minimum of content of a polymer, 0.1 mass part is preferred to 100 mass parts of [A] polymer, and 1 mass part is more preferred. The upper limit of the content is preferably 20 parts by mass, and more preferably 10 parts by mass. [E] By making content of a polymer into the said range, the water repellency of the resist film surface formed can be raised more moderately.

([E] Polymer Synthesis Method)
[E] As a method for synthesizing the polymer, for example, it can be synthesized according to a method similar to the method for synthesizing the polymer [A]. [E] The Mw of the polymer is preferably 1,000 or more and 50,000 or less, more preferably 1,000 or more and 30,000 or less, and still more preferably 1,000 or more and 10,000 or less. [E] When the Mw of the polymer is less than 1,000, a sufficient advancing contact angle may not be obtained.

<Other optional components>
The radiation-sensitive resin composition may contain an uneven distribution accelerator, a surfactant, a sensitizer, and the like as other components in addition to the above components. In addition, the said radiation sensitive resin composition may contain 2 or more types of said other components.

[Uneven distribution promoter]
When the radiation sensitive resin composition contains an [E] fluorine atom-containing polymer, the uneven distribution accelerator has an effect of unevenly distributing the [E] fluorine atom containing polymer on the resist film surface more efficiently. It is what has. By adding the uneven distribution accelerator to the radiation sensitive resin composition, the amount of the water repellent additive added can be reduced as compared with the conventional case. Therefore, it is possible to further suppress the elution of components from the resist film into the immersion liquid without damaging the basic resist characteristics such as LWR, development defects, and pattern collapse resistance, and to perform immersion exposure at a higher speed by high-speed scanning. As a result, the hydrophobicity of the resist film surface that suppresses immersion-derived defects such as watermark defects can be improved. Examples of such an uneven distribution promoter include low molecular compounds having a relative dielectric constant of 30 or more and 200 or less and a boiling point at 1 atm of 100 ° C. or more. Examples of such compounds include lactone compounds, carbonate compounds, nitrile compounds, and polyhydric alcohols.

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

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

  Examples of the nitrile compound include succinonitrile.

  Examples of the polyhydric alcohol include glycerin.

  Among these, lactone compounds and carbonate compounds are preferable, γ-butyrolactone and propylene carbonate are more preferable, and γ-butyrolactone is particularly preferable.

[Surfactant]
Surfactants have the effect of improving coatability, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. Nonionic surfactants such as stearate are listed. Examples of commercially available products include KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), MegaFac F171, F173 (above, manufactured by Dainippon Ink & Chemicals), Fluorad FC430, FC431 ( As above, manufactured by Sumitomo 3M, Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, Asahi Glass Industry) Manufactured) and the like.

[Sensitizer]
A sensitizer exhibits the effect | action which increases the production amount of a [B] acid generator, and there exists an effect which improves the "apparent sensitivity" of the said radiation sensitive resin composition. Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like.

<Method for preparing radiation-sensitive resin composition>
The said radiation sensitive resin composition can be prepared, for example by mixing a [A] polymer, a [B] acid generator, and another component in a [C] solvent in a predetermined ratio. In use, the radiation-sensitive resin composition is usually prepared by dissolving in a solvent and then filtering with, for example, a filter having a pore diameter of about 200 nm. As a minimum of the total solid content concentration at the time of dissolving in a solvent, it is usually 1 mass% and 1.5 mass% is preferred. The upper limit of the total solid content is usually 30% by mass, and preferably 25% by mass.

  The said radiation sensitive resin composition can be used suitably for organic solvent image development. As described above, the radiation-sensitive resin composition is considered to effectively improve the affinity between the [A] polymer and the organic solvent by having the above-described configuration. Therefore, when used for organic solvent development, the LWR Performance and the like can be improved.

  The radiation sensitive resin composition can be suitably used for alkaline aqueous solution development. As described above, the radiation-sensitive resin composition has the above-described configuration, so that the solubility of the polymer [A] in the alkaline aqueous solution is reduced, and the unexposed portion of the formed resist film is dissolved in the alkaline aqueous solution. Therefore, when used for alkaline aqueous solution development, LWR performance and the like can be improved.

<Method for forming resist pattern>
The resist pattern forming method using the radiation sensitive resin composition includes (1) a step of forming a resist film on a substrate using the radiation sensitive resin composition (hereinafter, also referred to as “step (1)”). (2) a step of exposing the resist film (hereinafter also referred to as “step (2)”), and (3) a step of developing the exposed resist film (hereinafter also referred to as “step (3)”). Have Hereinafter, each process is explained in full detail.

[Step (1)]
In this step, a resist film is formed on the substrate using the radiation sensitive resin composition. As the substrate, for example, a conventionally known substrate such as a silicon wafer or a wafer coated with aluminum can be used. Further, for example, an organic or inorganic lower-layer antireflection film disclosed in Japanese Patent Publication No. 6-12452, Japanese Patent Application Laid-Open No. 59-93448, or the like may be formed on the substrate.

  Examples of the coating method include spin coating (spin coating), cast coating, and roll coating. In addition, as a minimum of the film thickness of the resist film formed, it is 10 nm normally and 10 nm is preferable. The upper limit of the film thickness is usually 1,000 nm, and preferably 500 nm.

  After apply | coating the said radiation sensitive resin composition, you may volatilize the solvent in a coating film by prebaking (PB) as needed. The temperature condition of PB is appropriately selected according to the composition of the radiation sensitive resin composition, but the lower limit of the temperature is usually 30 ° C., and preferably 50 ° C. The upper limit of the temperature is usually 200 ° C, preferably 150 ° C.

[Step (2)]
In this step, exposure is performed by reducing and projecting onto a desired region of the resist film formed in step (1) through a mask having a specific pattern and, if necessary, an immersion liquid. For example, an isotrench pattern can be formed by performing reduced projection exposure on a desired region through an isoline pattern mask. Moreover, you may perform exposure twice or more. In addition, as an immersion liquid used in the case of exposure, water, a fluorine-type inert liquid, etc. are mentioned, for example. The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient that is as small as possible so as to minimize distortion of the optical image projected onto the film. When the exposure light is ArF excimer laser light (wavelength 193 nm), water is preferable from the viewpoints of availability and ease of handling in addition to the above-described viewpoints. When water is used, an additive that decreases the surface tension of water and increases the surface activity may be added in a small proportion. This additive is preferably one that does not dissolve the resist layer on the wafer and can ignore the influence on the optical coating on the lower surface of the lens. The water used is preferably distilled water.

  The exposure light used for the exposure is appropriately selected according to the type of the [B] acid generator, and examples thereof include ultraviolet rays, far ultraviolet rays, EUV (ultra-ultraviolet rays), X-rays, and charged particle beams. Of these, far ultraviolet rays such as ArF excimer laser light and KrF excimer laser light (wavelength 248 nm) are preferable, and ArF excimer laser light is more preferable. The exposure conditions such as the exposure amount are appropriately selected according to the blending composition of the radiation-sensitive resin composition, the type of additive, and the like.

  In this step, post-exposure baking (PEB) is preferably performed after exposure. By performing PEB, the dissociation reaction of the acid dissociable group in the radiation sensitive resin composition can proceed smoothly. As a minimum of PEB temperature, it is usually 30 ° C and 50 ° C or more is preferred. Regarding the upper limit, it is usually less than 200 ° C, preferably less than 150 ° C. When the temperature is lower than 30 ° C., the dissociation reaction may not proceed smoothly. On the other hand, when the temperature is 200 ° C. or higher, the acid generated from the [B] acid generator diffuses widely to the unexposed area and is good. There is a possibility that a pattern cannot be obtained.

[Step (3)]
In this step, after the step (2), development is performed using a developer to form a resist pattern. As a developing solution, in the case of organic solvent development, it is preferable to use a negative developing solution containing 80% by mass or more of an organic solvent. The negative developer is a developer that selectively dissolves and removes the low-exposed portion and the unexposed portion. The organic solvent contained in the negative developer is preferably at least one organic solvent selected from the group consisting of carboxylic acid alkyl esters having 3 to 7 carbon atoms and dialkyl ketones having 3 to 10 carbon atoms. By using the specific organic solvent as the developer, it is considered that the solubility of the radiation-sensitive resin composition in the developer is further improved, and the LWR performance and the like are further improved.

  Examples of the carboxylic acid alkyl ester having 3 to 7 carbon atoms include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, iso-propyl acetate, and n-butyl acetate. Iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate and the like.

  Examples of the dialkyl ketone having 3 to 10 carbon atoms include acetone, 2-butanone, methyl isoamyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, and methyl-n-pentyl. Examples include ketone and ethyl-n-butyl ketone.

  Of these, n-butyl acetate and methyl amyl ketone are preferred. These organic solvents may be used alone or in combination of two or more.

  In the case of aqueous alkali development, examples of the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-propyl. Amine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1, It is preferable to use an alkaline aqueous solution in which at least one of alkaline compounds such as 5-diazabicyclo- [4.3.0] -5-nonene is dissolved.

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

<Polymer>
The polymer has a structural unit (I) represented by the above formula (1). Therefore, the polymer can be suitably used as a component of the radiation sensitive resin composition. The polymer may be used as a base polymer, or may be used as a water repellent additive by containing a structural unit containing a fluorine atom.

<Compound>
The compound is represented by the above formula (i). Since the compound has a structure represented by the above formula (i), it can be suitably used as a monomer compound in which the structural unit (I) is incorporated into the polymer.

  In addition, since the detailed description of the said polymer and the said compound is performed in the term of the [A] polymer contained in the said radiation sensitive resin composition, it abbreviate | omits here.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In addition, each measurement in an Example and a comparative example was performed with the following method.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Using Tosoh's GPC columns ("G2000HXL", "G3000HXL", "G4000HXL"), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, sample concentration: 1.0% by mass, sample Injection amount: 100 μL, column temperature: 40 ° C., detector: measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of a differential refractometer. The polydispersity (Mw / Mn) was calculated from the measurement results of Mw and Mn.

[ ¹³ C-NMR analysis]
Using “JNM-ECX400” manufactured by JEOL Ltd. as the measuring device and deuterated chloroform as the measuring solvent, analysis was performed to determine the content ratio (mol%) of each structural unit in each polymer.

<Synthesis of compounds>
[Example 1] (Synthesis of Compound (M-1))
To a 300 mL round bottom flask, 8.67 g (133 mmol) of zinc powder, 70 mL of tetrahydrofuran and 0.852 g (7.85 mmol) of trimethylsilyl chloride were added and stirred at room temperature for 30 minutes. There, a solution in which 13.0 g (78.5 mmol) of 5-hydroxyadamantan-2-one and 19.7 g (102 mmol) of ethyl bromomethacrylate was dissolved in 60 mL of tetrahydrofuran was slowly kept at an internal temperature of 40 ° C. or lower. It was dripped. After completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours, and 5 g of silica gel was added to stop the reaction. Insoluble material was removed by filtration, ethyl acetate was added, and the mixture was washed 3 times with a saturated aqueous ammonium chloride solution. After drying with anhydrous sodium sulfate, the solvent was distilled off. By purification by column chromatography, 14.6 g (yield 79%) of compound (m-1) was obtained.

  To a 200 mL round bottom flask, 7.0 g (29.9 mmol) of compound (m-1) and 50 mL of methanol were added, and cooled to 0 ° C. in an ice bath. Thereto, 0.969 g (25.6 mmol) of sodium borohydride was slowly added as a solid. The mixture was stirred at 0 ° C. for 3 hours. After 2 g of silica gel was added to stop the reaction, insoluble matters were removed by filtration. Ethyl acetate was added, washed twice with water, and dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was purified by column chromatography to obtain 4.60 g (yield 65%) of compound (m-2).

  In a 300 mL round bottom flask, 4.50 g (19.0 mmol) of compound (m-2), 2.31 g (22.9 mmol) of triethylamine, and 0.641 g of 1,4-diazabicyclo [2.2.2] octane (5. 71 mmol) and 60 mL of N, N-dimethylformamide were added, and the mixture was stirred at room temperature in a water bath. Thereto, 2.59 g (24.8 mmol) of methacryloyl chloride was slowly added dropwise. After completion of dropping, the mixture was stirred at room temperature for 5 hours. Water was added to stop the reaction, and the organic layer was washed twice with water. After distilling off the solvent, 4.25 g (yield 73%) of (M-1) was obtained by purification by column chromatography.

[Examples 2 to 17] (Synthesis of compounds (M-2) to (M-17))
The precursors were appropriately selected, and the same operations as in Example 1 were performed to synthesize compounds represented by the following formulas (M-2) to (M-17).

<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.

[Example 18] (Synthesis of polymer (A-1))
Compound (M′-1) 6.51 g (30 mol%), Compound (M′-2) 6.30 g (40 mol%), Compound (M′-3) 4.37 g (20 mol%) and Compound ( M-1) 2.82 g (10 mol%) was dissolved in 40 g of 2-butanone, and 0.76 g of AIBN (5 mol% based on the total monomers) was added as an initiator to prepare a monomer solution. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, and then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The polymerization solution cooled in 400 g of methanol was added, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 80 g of methanol, filtered and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-1) (15.8 g, yield 79). %). Mw of the polymer (A-1) was 7,400, and Mw / Mn was 1.54. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M′-1), (M′-2), (M′-3) and (M-1) was 30.1 mol, respectively. %, 40.1 mol%, 19.6 mol% and 10.2 mol%.

[Example 38] (Synthesis of polymer (A-21))
Compound (M′-4) 49.19 g (60 mol%), Compound (M′-5) 25.11 g (20 mol%), Compound (M-2) 25.71 g (20 mol%), as an initiator After dissolving 4.15 g of AIBN (5 mol% based on the total monomers) and 1.14 g of t-dodecyl mercaptan (1.5 mol% based on the total monomers) in 100 g of propylene glycol monomethyl ether, the reaction was performed in a nitrogen atmosphere. The temperature was maintained at 70 ° C. and copolymerization was performed for 16 hours. After completion of the polymerization reaction, the polymer solution was dropped into 1,000 g of n-hexane to solidify and purify the polymer. Next, 150 g of propylene glycol monomethyl ether was added to the polymer again, and then 150 g of methanol, 34 g of triethylamine and 6 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the resulting polymer was dissolved in 150 g of acetone, then dropped into 2,000 g of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. It was made to dry for a time and the white powdery polymer (A-21) was obtained (66.2g, yield 76%). Mw of the polymer (A-21) was 7600, and Mw / Mn was 1.91. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from p-hydroxystyrene, (M′-5) and (M-2) was 60.2 mol%, 19.8 mol% and 20 respectively. 0.0 mol%.

[Examples 19 to 37, 39 to 43, and Synthesis Examples 1 to 9] (Synthesis of Polymers (A-2) to (A-20) and (A-22) to (A-35))
Polymers (A-2) to (A-20) and (A-22) to (A-) are selected by appropriately selecting monomers as shown in Tables 1 and 2 and performing the same operations as in Example 18. 35) was synthesized.

[Synthesis Example 10] (Synthesis of Polymer (E-1))
Compound (M′-6) 79.9 g (70 mol%) and compound (M′-17) 20.91 g (30 mol%) were dissolved in 100 g of 2-butanone, and dimethyl 2,2 ′ as an initiator. -A monomer solution was prepared by dissolving 4.77 g of azobisisobutyrate. Next, a 1,000 mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes and then heated to 80 ° C. with stirring, and the monomer solution prepared above was added dropwise over 3 hours using a dropping funnel. . The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The reaction solution was transferred to a 2 L separatory funnel, and then the polymerization solution was uniformly diluted with 150 g of n-hexane, and 600 g of methanol was added and mixed. Next, 30 g of distilled water was added, and the mixture was further stirred and allowed to stand for 30 minutes. Thereafter, the lower layer was recovered to obtain a propylene glycol monomethyl ether acetate solution containing the polymer (E-1) as a solid content (yield 60%). Mw of the polymer (E-1) was 7,200, and Mw / Mn was 2.00. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M′-6) and (M′-17) was 71.1 mol% and 28.9 mol%, respectively.

<Preparation of radiation sensitive resin composition (I)>
[B] acid generator used for the preparation of the radiation sensitive resin compositions (I) of the following Examples 44 to 45, 48 to 59, 61 to 63, Reference Examples 46 to 47, 60 and Comparative Examples 1 to 8, [D] Acid diffusion controller and [C] solvent are shown below.

[[B] acid generator]
B-1: Triphenylsulfonium 2- (adamantan-1-ylcarbonyloxy) -1,1,3,3,3-pentafluoropropane-1-sulfonate B-2: Triphenylsulfonium norbornane sultone-2-yloxy Carbonyl difluoromethanesulfonate B-3: Triphenylsulfonium 3- (piperidin-1-ylsulfonyl) -1,1,2,2,3,3-hexafluoropropane-1-sulfonate B-4: Triphenylsulfonium adamantane- 1-yloxycarbonyldifluoromethanesulfonate Each structural formula is shown below.

[[D] acid diffusion controller]
D-1: Triphenylsulfonium salicylate D-2: Triphenylsulfonium 10-camphorsulfonate D-3: N- (n-undecan-1-ylcarbonyloxyethyl) morpholine D-4: 2,6-dii -Propylaniline D-5: Tri-n-pentylamine Each structural formula is shown below.

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

[[F] uneven distribution promoter]
F-1: γ-butyrolactone

[Radiosensitive resin composition for ArF exposure]
[Example 44]
[A] 100 parts by mass of (A-1) as a polymer, [B] 8.5 parts by mass of (B-1) as an acid generator, [D] (D-1) 2 as an acid diffusion controller 3 parts by weight, (E-1) 3 parts by weight as a polymer, (C-1) 2,240 parts by weight and (C-2) 960 parts by weight as a solvent, and [F The radiation-sensitive resin composition (J-1) was prepared by blending 30 parts by mass of (F-1) as an uneven distribution accelerator and filtering with a membrane filter having a pore size of 0.2 μm.

[Examples 45, 48-59, 61-63, Reference Examples 46-47, 60 and Comparative Examples 1-8]
Each radiation-sensitive resin composition was prepared in the same manner as in Example 44 except that the components of the types and blending amounts shown in Table 3 below were used.

<Formation of resist pattern (1)>
A 12-inch silicon wafer surface was coated with a composition for forming a lower antireflection film (“ARC66” from Brewer Science Co., Ltd.) using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron), and then 205 ° C. Was heated for 60 seconds to form a lower antireflection film having a thickness of 105 nm. On the lower antireflection film, each of the prepared radiation sensitive resin compositions was applied using the spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 90 nm. Next, this resist film was subjected to an optical condition of NA = 1.3 and dipole (Sigma 0.977 / 0.782) using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON). , Exposed through a 40 nm line and space (1L1S) mask pattern. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, the resist was alkali-developed using a 2.38 mass% TMAH aqueous solution as an alkali developer, washed with water, and dried to form a positive resist pattern. When this resist pattern is formed, the exposure amount that is formed in a one-to-one line-and-space pattern with a line width of 40 nm is defined as the optimum exposure amount. did.

<Formation of resist pattern (2)>
A negative resist pattern was prepared in the same manner as in the above resist pattern formation (1) except that n-butyl acetate was used instead of the TMAH aqueous solution and the organic solvent was developed, and washing with water was not performed. Formed.

<Evaluation>
About the formed resist pattern, each radiation sensitive resin composition was evaluated by measuring according to the following method. A scanning electron microscope (Hitachi High-Technologies “CG-4100”) was used for measuring the resist pattern.

[LWR performance]
The resist pattern was observed from above the pattern using the scanning electron microscope. A total of 50 line widths were measured at arbitrary points, and a 3-sigma value was obtained from the distribution of the measured values, and this was defined as LWR performance (nm). The LWR performance indicates that the smaller the value, the better.

[Resolution]
The dimension of the minimum resist pattern that can be resolved at the optimum exposure dose is measured, and the measurement result is defined as resolution (nm). The smaller the measured value, the better the resolution.

[Cross-sectional shape]
The cross-sectional shape of the resist pattern resolved at the optimum exposure dose was observed, and the line width Lb in the middle in the height direction of the resist pattern and the line width La at the top of the film were measured. La / Lb was calculated from these measured values and used as an index of the rectangularity of the cross-sectional shape. When 0.9 ≦ La / Lb ≦ 1.1, the cross-sectional shape can be evaluated as “good”, and when it is out of the above range, the cross-sectional shape can be evaluated as “defective”.

[Depth of focus]
In the resist pattern resolved at the above optimum exposure amount, the dimension when the focus is changed in the depth direction is observed, and the depth direction in which the pattern dimension falls within 90% to 110% of the standard without any bridge or residue. Was measured, and the measurement result was defined as the depth of focus (nm). The larger the measured value, the better the depth of focus.

  The evaluation results are shown in Table 4.

[Resistence of resist film shrinkage]
A 12-inch silicon wafer surface was coated with a composition for forming a lower antireflection film (“ARC66” from Brewer Science Co., Ltd.) using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron), and then 205 ° C. Was heated for 60 seconds to form a lower antireflection film having a thickness of 105 nm. On the lower antireflection film, each of the prepared radiation sensitive resin compositions was applied using the spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 90 nm. Next, the resist film was exposed at 70 mJ using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON), and then the film thickness was measured to obtain the film thickness A. Then, after implementing PEB for 60 seconds at 90 degreeC, the film thickness measurement was implemented again and the film thickness B was calculated | required. At this time, 100 × (A−B) / A (%) was obtained and used as the film shrinkage rate by PEB. The evaluation results are shown in Table 5. The smaller the measured value, the better the film shrinkage by PEB.

[Defect suppression]
A coating film is formed with a radiation-sensitive resin composition on a 12-inch silicon wafer on which a lower antireflection film is formed with a composition for forming an lower antireflection film (“ARC66” of Nissan Chemical Co., Ltd.), and is heated at 120 ° C. for 50 seconds. SB was performed to form a resist film having a thickness of 110 nm. Next, an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON) was used for this resist film, and the target size was 40 nm in width under the conditions of NA = 1.3, ratio = 0.800, Dipole. It exposed through the mask pattern for line and space (1L / 1S) formation. After exposure, PEB was performed at 95 ° C. for 50 seconds. Thereafter, development is performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 10 seconds using a GP nozzle of a developing device (“Clean Track ACT8” manufactured by Tokyo Electron), rinsing with pure water for 15 seconds, and liquid at 2,000 rpm. By shaking off and drying, a positive resist pattern was formed. At this time, the exposure amount for forming 1 L / 1S having a width of 40 nm was determined as the optimum exposure amount. With this optimum exposure amount, 1 L / 1S having a line width of 40 nm was formed on the entire surface of the wafer to obtain a defect inspection wafer. A scanning electron microscope (Hitachi High-Technologies “CC-4000”) was used for length measurement. The number of defects on the defect inspection wafer was measured using a defect inspection apparatus (“KLA2810” manufactured by KLA-Tencor). Then, the measured defects were classified into those judged to be derived from the resist film and foreign matters derived from the outside, and the number of those judged to be derived from the resist film was calculated. The evaluation results are shown in Table 6. The smaller the number of defects judged to be derived from this resist film, the better the defect suppression.

[Radiation sensitive resin composition for electron beam exposure]
[Example 64]
[A] 100 parts by mass of (A-1) as a polymer, [B] 20 parts by mass of (B-1) as an acid generator, [D] 3.6 (D-1) as an acid diffusion controller Radiation sensitive resin by blending part by mass, (C-1) 4,280 parts by mass as [C] solvent and (C-2) 1,830 parts by mass, and filtering through a membrane filter having a pore size of 0.2 μm A composition (J-21) was prepared.

[Examples 66, 69 to 71, Reference Examples 65, 67 to 68, and Comparative Examples 9 to 14]
Except having used each component of the kind and compounding quantity which are shown in following Table 7, it operated similarly to Example 64 and prepared each radiation sensitive resin composition.

<Formation of resist pattern (3)>
Using a spin coater (“CLEAN TRACK ACT8” manufactured by Tokyo Electron Ltd.) on the surface of an 8-inch silicon wafer, each radiation-sensitive resin composition described in Table 7 was applied, and PB was performed at 90 ° C. for 60 seconds. . Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 50 nm. Next, the resist film was irradiated with an electron beam by using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 120 ° C. for 60 seconds. Thereafter, development was performed at 23 ° C. for 30 seconds using a 2.38 mass% TMAH aqueous solution as an alkali developer, washed with water, and dried to form a positive resist pattern.

<Formation of resist pattern (4)>
A negative resist pattern was prepared in the same manner as in the above resist pattern formation (1) except that n-butyl acetate was used instead of the TMAH aqueous solution and the organic solvent was developed, and washing with water was not performed. Formed.

<Evaluation>
About the resist pattern formed using each said radiation sensitive resin composition, evaluation similar to the said Examples 44-45, 48-59, 61-63, Reference Examples 46-47, 60 and Comparative Examples 1-8 was carried out. Carried out. The evaluation results are shown in Table 8.

  From the results of Tables 3 to 8, according to the radiation-sensitive resin compositions of the examples, the LWR performance was obtained in both cases of ArF exposure and electron beam exposure, and in both cases of alkali development and organic solvent development. It can be seen that the present invention is excellent in resolution, rectangularity of the cross-sectional shape, depth of focus, resist film shrinkage suppression, and defect generation suppression. In general, electron beam exposure is known to show the same tendency as in EUV exposure. Therefore, even in the case of EUV exposure, according to the radiation-sensitive resin composition of the examples. It is estimated that the LWR performance is excellent.

  According to the radiation-sensitive resin composition of the present invention, a resist pattern that exhibits excellent depth of focus and resist film shrinkage suppression, low LWR, high resolution, excellent cross-sectional rectangularity, and few defects. Can be formed. The polymer of this invention can be used suitably as a polymer component of the said radiation sensitive resin composition. The compound of the present invention can be suitably used as a raw material monomer for the polymer. Therefore, these can be suitably used in a lithography process that requires further miniaturization.

Claims (4)

A polymer having a first structural unit represented by the following formula (1);
A radiation-sensitive resin composition containing a radiation-sensitive acid generator.

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^{2 to} R ⁶ are each independently a hydrogen atom or a monovalent group having 1 to 20 carbon atoms. A is an integer of 1 to 5. When a is 2 or more, the plurality of R ⁵ may be the same or different, and the plurality of R ⁶ may be the same or different. However, at least one of the one or more R ⁵ and the one or more R ⁶ is the above monovalent organic group, L is a divalent hydrocarbon group having 1 to 20 carbon atoms or the above carbonization. A group in which some or all of the hydrogen atoms of the hydrogen group are substituted with substituents, provided that when R ² and R ³ are both hydrogen atoms, R ⁴ is the above monovalent organic group, and R ⁴ , L, 1 or more R ⁵ and one or more of two or more are combined with each other of R ⁶ these If with bonded carbon atom or chain of atoms which may form a ring structure composed of 3 to 20 carbon atoms .R ² is the monovalent organic group and R ³ is a hydrogen ^atom, R 4, ^L, 1 or R ⁵ and one or more ring structures comprised 3 to 20 carbon atoms with two or more carbon atoms or a chain of atoms aligned they are bound to each other of R ⁶ may be formed, In addition, a ring structure having 3 to 20 carbon atoms constituted by a carbon atom or an atomic chain in which two or more of R ² , L, one or more R ⁵ and one or more R ⁶ are combined with each other and bonded together When R ² and R ³ are both monovalent organic groups, R ² , R ³ , R ⁴ , L, one or more R ⁵ and one or more R ⁶ Constructed with two or more carbon atoms or atomic chains that are joined together A C3-C20 ring structure may be formed.)   The radiation sensitive resin composition according to claim 1, wherein the polymer further includes a second structural unit which is a structural unit other than the first structural unit and includes an acid dissociable group.   The radiation-sensitive resin composition according to claim 1 or 2, which is used for organic solvent development.   The radiation-sensitive resin composition according to claim 1, which is used for developing an aqueous alkali solution.