JP6237099B2 - Radiation-sensitive resin composition and resist pattern forming method - Google Patents

Description

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

  Conventionally, in the manufacturing process of semiconductor devices such as IC and LSI, fine processing by lithography using a radiation-sensitive resin composition has been performed. In recent years, with the high integration of integrated circuits, the formation of ultrafine patterns in the submicron region and the quarter micron region has been required. Along with this, the radiation used for exposure also has shorter wavelengths such as g-line to i-line, KrF excimer laser light, and further ArF excimer laser light. In particular, recently, development of a lithography technique using extreme ultraviolet (EUV), X-ray, electron beam (EB) or the like (hereinafter also referred to as “EUV”) having a wavelength shorter than that of excimer laser light has been promoted ( JP, 2006-171440, JP, 2011-16746, and JP, 2010-204634).

  The lithography technique using the EUV or the like is expected as a next-generation pattern forming technique capable of forming a pattern in an ultrafine region of 32 nm or less. However, in exposure using EUV or the like, high sensitivity of the radiation-sensitive resin composition is required for reasons such as difficulty in increasing the radiation output. In addition, it is also required to improve LWR (Line Width Roughness) performance and resolution. However, the conventional radiation-sensitive resin composition cannot satisfy these requirements.

JP 2006-171440 PR JP2011-16746 JP 2010-204634 PR

  The present invention has been made based on the circumstances as described above, and an object thereof is to provide a radiation-sensitive resin composition having excellent sensitivity and excellent LWR performance and resolution in exposure such as EUV. There is.

The invention made to solve the above problems is
A polymer having an acid dissociable group (hereinafter, also referred to as “[A] polymer”),
An organic compound (hereinafter also referred to as “[B] organic compound”) that emits two or more electrons with a change in chemical structure by the action of one radiation particle, and [C] an acid by the action of radiation. Generated acid generator (hereinafter also referred to as “[C] acid generator”)
Is a radiation-sensitive resin composition.

Another invention made to solve the above problems is as follows:
Forming a resist film;
A step of exposing the resist film, and a step of developing the exposed resist film,
It is a resist pattern formation method which forms the said resist film with the said radiation sensitive resin composition.

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

  According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern with low LWR and high resolution can be formed while exhibiting high sensitivity. Therefore, they can be suitably used for forming a fine resist pattern in the lithography process of various electronic devices such as semiconductor devices and liquid crystal devices.

<Radiation sensitive resin composition>
The radiation sensitive resin composition of the present invention contains a [A] polymer, a [B] organic compound, and a [C] acid generator. Moreover, the said radiation sensitive resin composition may contain a [D] acid diffusion control body and a [E] solvent as a suitable component, and contains other arbitrary components in the range which does not impair the effect of this invention. May be.
Hereinafter, each component will be described in detail.

<[A] polymer>
[A] The polymer is a polymer having an acid dissociable group. The “acid-dissociable group” refers to a group that replaces a hydrogen atom such as a carboxyl group or a hydroxyl group and that dissociates by the action of an acid. According to the radiation-sensitive resin composition, the acid-dissociable group of the [A] polymer is dissociated in the exposed area by the action of an acid generated from the [C] acid generator, which will be described later, and the solubility in the developer By changing, a resist pattern can be formed. [A] The polymer is not particularly limited as long as it has an acid-dissociable group, and the position of the acid-dissociable group may be bonded to any of the main chain, side chain, and terminal. It is preferable to have a structural unit containing an acid dissociable group (hereinafter also referred to as “structural unit (I)”).

The polymer [A] may have a structural unit (II) containing a phenolic hydroxyl group, which will be described later, in addition to the structural unit (I), and other than the structural unit (I) and the structural unit (II). Other structural units may be included.
Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group. As this acid dissociable group, a group represented by the following formula (7) is preferable. This acid dissociable group is bonded to a polar group such as —COO— or —O— in the [A] polymer.

In said formula (7), R ^<p1> is a C1-C20 alkyl group, a C3-C20 cycloalkyl group, or a C6-C20 aryl group. R ^p2 and R ^p3 are each independently an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms, or these groups are combined with each other and configured together with the carbon atom to which they are bonded. Represents an alicyclic structure having 3 to 20 ring members. * Indicates the binding site to the polar group of the [A] polymer.

Examples of the alkyl group having 1 to 20 carbon atoms represented by R ^p1 , R ^p2 and R ^p3 include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl. Group, sec-butyl group, t-butyl group and the like.

Examples of the cycloalkyl 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 cyclooctyl group, a norbornyl group, an adamantyl group, and the like. Is mentioned.

Examples of the aryl group having 6 to 20 carbon atoms represented by R ^p1 include a phenyl group, a tolyl group, a xylyl group, a mesityl group, a naphthyl group, and an anthryl group.

Examples of the alicyclic structure having 3 to 20 ring members constituted by the carbon atoms to which these groups of R ^p2 and R ^p3 are combined and bonded to each other include, for example, cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane Examples thereof include a structure, a cyclooctane structure, a norbornane structure, and an adamantane structure.

  Examples of the structural unit (I) include a structural unit represented by the following formula (7-1) (hereinafter also referred to as “structural unit (I-1)”) and a following formula (7-2). A structural unit (hereinafter also referred to as “structural unit (I-2)”).

In the above formulas (7-1) and (7-2), R ^p1 , R ^p2 and R ^p3 have the same ^{meaning as} in the above formula (7).
In said formula (7-1), ^RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.
In the above formula (7-2), R ^B is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L ¹ is a single bond, —O—, —COO— or —CONH—.

R ^A is preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (I-1).
Examples of the R ^B, in view of copolymerizability of the monomer giving the structural unit (I-2), a hydrogen atom, preferably a methyl group, and more preferably a hydrogen atom.

  As the structural unit (I-1), structural units represented by the following formulas (7-1-1) to (7-1-4) (hereinafter referred to as “structural units (I-1-1) to (I -1-4) ”is a structural unit represented by the following formula (7-2-1) as the structural unit (I-2) (hereinafter referred to as“ structural unit (I-2-1) ”). Are also preferred).

In the above formulas (7-1-1) to (7-2-1), R ^{p1 to} R ^p3 , R ^A and R ^B have the same meanings as the above formulas (7-1) and (7-2). n _p is each independently an integer of 1 to 4.

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

In the above formula, R ^A has the same meaning as in the above formula (7-1).

  Examples of the structural unit (I-2) include structural units represented by the following formulas.

In the above formula, R ^B has the same meaning as in the above formula (7-2).

  As the structural unit (I), the structural unit (I-1) is preferable, the structural unit (I-1-1) is more preferable, and the structural unit derived from 2-ethyl-2-adamantyl (meth) acrylate is more preferable. .

  As a content rate of structural unit (I), 10 mol%-90 mol% are preferable with respect to all the structural units which comprise a [A] polymer, 20 mol%-70 mol% are more preferable, 25 mol% More preferred is ˜50 mol%. By making the content rate of structural unit (I) into the said range, the sensitivity of the said radiation sensitive resin composition, LWR performance, and resolution can be improved more.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a phenolic hydroxyl group. The said radiation sensitive resin composition can improve the sensitivity with respect to EUV etc. more because a [A] polymer has structural unit (II).

  Examples of the structural unit (II) include a structural unit represented by the following formula (8).

In said formula (8), R <^C> is a hydrogen atom or a methyl group. L ² is a single bond or a divalent organic group having 1 to 20 carbon atoms. ^RD is a monovalent organic group having 1 to 20 carbon atoms. k is an integer of 0-9. When k is 2 or more, the plurality of R ^D may be the same or different. j is an integer of 1 to 3. s is an integer of 0-2.

As said ^RC , a hydrogen atom is preferable from a copolymerizable viewpoint of the monomer which gives structural unit (II).

Examples of the divalent organic group having 1 to 20 carbon atoms represented by L ² include, for example, a hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon boundary of the hydrocarbon group, or a terminal on the bond side. O—, —NH—, —CO—, —CS—, a group (α) containing a divalent heteroatom-containing group such as a combination of these, a hydrocarbon atom and a hydrogen atom of the group (α) Examples include a group in which a part or all of them are substituted with a monovalent heteroatom-containing group such as a hydroxy group, a halogen atom, or a cyano group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by ^RD include one hydrogen atom in the group exemplified as the divalent organic group having 1 to 20 carbon atoms represented by L ² above. Examples include groups to which atoms are added.

As the ^{L 2,} preferably a single bond.
The ^RD is preferably a hydrocarbon group, more preferably a chain hydrocarbon group, still more preferably an alkyl group, and particularly preferably a methyl group.

As said k, the integer of 0-2 is preferable, 0 or 1 is more preferable, and 0 is especially preferable.
J is preferably 1 or 2, and more preferably 1.
As said s, 0 or 1 is preferable and 0 is more preferable.

  As the structural unit (II), for example, structural units represented by the following formulas (8-1) to (8-6) (hereinafter also referred to as “structural units (II-1) to (II-6)”) Etc.

In the above formulas (8-1) to (8-6), R ^C has the same meaning as in the above formula (8).

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

  The content ratio of the structural unit (II) is preferably 0 mol% to 90 mol%, more preferably 10 mol% to 80 mol%, more preferably 40 mol%, based on all structural units constituting the [A] polymer. More preferred is ˜75 mol%. By making the content rate of structural unit (II) into the said range, the sensitivity with respect to EUV etc. of the said radiation sensitive resin composition can further be improved.

[Other structural units]
The above [A] polymer may have other structural units in addition to the structural unit (I) and the structural unit (II). Examples of the other structural units include a structural unit containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure, a structural unit containing a polar group, and a hydroxy group at the terminal. And a structural unit containing a group having at least one fluorine atom or a fluorinated alkyl group as the carbon atom adjacent to, a structural unit containing a non-acid dissociable alicyclic hydrocarbon group, and the like. Examples of the polar group include a hydroxy group, a carboxy group, a sulfonamide group, a ketonic carbonyl group, a cyano group, and a nitro group. As a content rate of the said other structural unit, 30 mol% or less is preferable with respect to all the structural units which comprise a [A] polymer, and 20 mol% or less is more preferable.

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

  Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpropylene). Pionitrile), azo radical initiators such as 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate; benzoyl peroxide, t-butyl hydroperoxide, And peroxide radical initiators such as cumene hydroperoxide. Of these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is more preferred. 1 type (s) or 2 or more types can be used for a radical polymerization initiator.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. 1 type (s) or 2 or more types can be used for the solvent used for the said superposition | polymerization.

  As reaction temperature in the said superposition | polymerization, 40 to 150 degreeC and 50 to 120 degreeC are preferable normally. The reaction time is usually preferably 1 hour to 48 hours and 1 hour to 24 hours.

  [A] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is not particularly limited, but is preferably 1,000 or more and 50,000 or less, and preferably 2,000 or more and 30,000 or less. More preferably, 3,000 or more and 20,000 or less are more preferable, and 4,000 or more and 15,000 are particularly preferable. [A] If the Mw of the polymer is less than the lower limit, the heat resistance of the resulting resist film may be lowered. [A] If the Mw of the polymer exceeds the above upper limit, the developability of the resist film may deteriorate.

  [A] The ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer (Mw / Mn (dispersion degree)) is usually from 1 to 5, preferably from 1 to 3, preferably from 1 to 2. The following is more preferable.

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

<[B] Organic compound>
[B] An organic compound is an organic compound that emits two or more electrons with a change in chemical structure by the action of one radiation particle. [B] The organic compound is a low molecular weight compound containing a carbon atom having the above-mentioned characteristics, and is preferably a compound having a molecular weight of 1,000 or less, more preferably 800 or less, and even more preferably 600 or less. “Radiation particle” means a unit of energy transfer in radiation, and means a photon when the radiation is an electromagnetic wave, and a particle when the radiation is a particle beam. Examples of the radiation include ultraviolet rays, far ultraviolet rays, EUV, X-rays, and γ rays as electromagnetic waves, and charged particle rays such as EB and α rays as particle rays. Among these, EUV, X-rays and EB are preferable, EUV and EB are more preferable, and EUV is more preferable from the viewpoint of a greater benefit from the sensitivity improvement effect of the present invention. “Emission of two or more electrons by the action of one radiation particle” means that two or more electrons are generated formally when one radiation particle energizes an organic compound [B]. The probability of electron emission is not considered. “Emitting electrons with a change in chemical structure” means that the mechanism of electron emission is, for example, due to the cleavage or generation of a covalent bond such as a carbon-carbon single bond or carbon-hydrogen bond, or a change in a conjugated system. It means that the molecular structure changes with the This change in chemical structure may be accompanied by emission of protons and the like together with electrons.

  The radiation-sensitive resin composition contains an organic compound [B] that emits two or more electrons by the action of one radiation particle, in addition to the [A] polymer and [C] acid generator. Thus, in exposure such as EUV, the sensitivity is excellent, and the LWR performance and the resolution are also excellent. The reason why the radiation-sensitive resin composition has the above-described configuration and exhibits the above-mentioned effects is not necessarily clear, but can be inferred as follows, for example. That is, in the radiation-sensitive resin composition, the radiation particles act on the [B] organic compound, two or more electrons are generated per radiation particle, and the generated electrons act on the [C] acid generator. Thus, it is considered that an acid can be generated. The mechanism of acid generation using such a [B] organic compound is, for example, more efficient than in the case of passing through electrons generated by radiation acting on the contained polymer as in the conventional radiation-sensitive resin composition. As a result, the radiation-sensitive resin composition is excellent in sensitivity in exposure such as EUV, and as a result, LWR performance and resolution are improved.

  [B] The organic compound is not particularly limited as long as it emits two or more electrons with a change in chemical structure by the action of one radiation particle. For example, the following formulas (1) to ( 5) (hereinafter also referred to as “compounds (1) to (5)”) and the like. Among these [B] organic compounds, these compounds are preferable because of their high electron emission efficiency.

The formula (1), ^{R 1} is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. R ^{2 to} R ⁶ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ³ and R ⁴ or R ⁵ and R ⁶ may be combined with each other to form a ring structure having 4 to 20 ring members together with the carbon atom to which they are bonded.
In the above formula (2), X ¹ and X ² are each independently OH or NHR ′. R ′ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. R ^{11 to} R ¹⁴ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ¹¹ and R ¹² or R ¹³ and R ¹⁴ may be combined with each other to form a ring structure having 4 to 20 ring members together with the carbon atom to which they are bonded.
In the above formula (3), Ar ^{1 to} Ar ⁵ are each independently a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms or a substituted or unsubstituted ring member having 4 to 20 ring members. It is a monovalent aromatic heterocyclic group. R ^{21 to} R ²⁵ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.
In the above formula (4), Ar ^{11 to} Ar ¹⁶ are each independently a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms or a substituted or unsubstituted ring member having 4 to 20 ring members. It is a monovalent aromatic heterocyclic group. Ar ¹³ and Ar ¹⁶ may be combined with each other to form a ring structure having 4 to 20 ring members together with the carbon atom to which they are bonded.
In the above formula (5), Ar ^{21 to} Ar ²⁴ are each independently a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms or a substituted or unsubstituted ring member having 4 to 20 ring members. It is a monovalent aromatic heterocyclic group. Ar ²¹ and Ar ²² or Ar ²³ and Ar ²⁴ may be combined with each other to form a ring structure having 4 to 20 ring members together with the carbon atom to which they are bonded. )

Examples of the alkyl group having 1 to 20 carbon atoms represented by R ¹ and R ′ include a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group. Octyl group, decyl group, dodecyl group, tetradodecyl group, octadodecyl group, eicosyl group and the like.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^{2 to} R ⁶ , R ^{11 to} R ¹⁴ and R ^{21 to} R ²⁵ include, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms. , A group (α) containing a divalent heteroatom-containing group at the carbon-carbon end or bond-end side of the hydrocarbon group, a part or all of the hydrogen atoms of the hydrocarbon group and the group (α). And a group substituted with a monovalent heteroatom-containing group.

  Examples of the hydrocarbon group having 1 to 20 carbon atoms include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic hydrocarbon having 6 to 20 carbon atoms. Groups and the like.

Examples of the chain hydrocarbon group include:
Alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl and n-pentyl;
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 cyclopropyl group, cyclobutyl group, cyclopentyl group, 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 phenyl, tolyl, xylyl, naphthyl and anthryl;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, and naphthylmethyl group.

Examples of the divalent heteroatom-containing group 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 monovalent heteroatom-containing group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group and nitro group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by Ar ^{1 to} Ar ⁵ , Ar ^{11 to} Ar ^16, and Ar ^{21 to} Ar ²⁴ are exemplified as the aromatic hydrocarbon group. Examples thereof include the same groups as those described above.

Examples of the monovalent aromatic heterocyclic group having 4 to 20 ring members represented by Ar ^{1 to} Ar ⁵ , Ar ^{11 to} Ar ¹⁶ and Ar ^{21 to} Ar ²⁴ include, for example, pyrrolyl group, furyl group, thienyl group, imidazolyl. Group, pyrazolyl group, oxazolyl group, isoxazole group, thiazolyl group, isothiazolyl group, pyridyl group, pyrimidyl group, pyridazyl group, pyrazyl group and the like.

Examples of the substituent of the aromatic hydrocarbon group and aromatic heterocyclic group represented by Ar ^{1 to} Ar ⁵ , Ar ^{11 to} Ar ^16, and Ar ^{21 to} Ar ²⁴ include the above R ^{2 to} R ⁶ and R ^11. exemplified monovalent organic group, and the like as to R ¹⁴ and ^R 21 ^{to R 25.}

  Examples of the compound (1) include compounds represented by the following formulas (1-a) to (1-f).

  Examples of the compound (2) include compounds represented by the following formulas (2-a) to (2-f).

  Examples of the compound (3) include compounds represented by the following formula (3-a).

  Examples of the compound (4) include a compound represented by the following formula (4-a), a compound represented by the following formula (4-b), and the like.

  Examples of the compound (5) include compounds represented by the following formulas (5-a) to (5-c).

[B] The content of the organic compound is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, with respect to 100 parts by mass of the polymer [A]. 1 part by mass or more and 10 parts by mass or less are more preferable.
[B] The content of the organic compound is preferably 0.5 mol% or more and 150 mol% or less, more preferably 2.5 mol% or more and 100 mol% or less with respect to 100 mol% of the [C] acid generator. 5 mol% or more and 50 mol% or less are more preferable.
[B] By making content of an organic compound into the said range, the sensitivity with respect to EUV etc. of the said radiation sensitive resin composition can further be improved. [B] One or more organic compounds can be used.

<[C] acid generator>
[C] The acid generator is a substance that generates an acid by the action of radiation. It is considered that the acid generator [C] can generate an acid by the action of electrons emitted from the organic compound [B] by the action of radiation particles, and the action of the acid in the exposed portion of the [A] polymer. A resist pattern can be formed by dissociating the acid-dissociable group and changing the solubility in a developer. The content form of the [C] acid generator in the radiation-sensitive resin composition may be a low molecular compound form (hereinafter also referred to as “[C] acid generator” as appropriate), as described later. It may be a form incorporated as a part or both of these forms.

  [C] Examples of the acid generator include a compound represented by the following formula (6) (hereinafter also referred to as “compound (6)”).

In the above formula (6), Q ⁺ is a monovalent radiation-sensitive onium cation. Y ⁻ is a monovalent organic oxoacid anion.

Examples of the monovalent radiation-sensitive onium cation represented by Q ⁺ include a sulfonium cation, a tetrahydrothiophenium cation, an iodonium cation, a phosphonium cation, a diazonium cation, and a pyridinium cation. Of these, a sulfonium cation, a tetrahydrothiophenium cation, and an iodonium cation are preferable.

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

In the above formula (Q-1), R ^a1 , R ^a2 and R ^a3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, substituted or unsubstituted. aromatic hydrocarbon group having 6 to 12 carbon atoms, a or a -OSO ₂ -R ^P or _-SO 2 -R ^Q, or two or more are combined with each other configured ring of these groups . R ^P and R ^Q are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2 and k3 are each independently an integer of 0 to 5. R ^a1 to R ^a3 and when ^{R P} and ^{R Q} are a plurality each of the plurality of ^R a1 ^{to R a3} and ^{R P} and ^{R Q} may be the same as or different from each other.
In the above formula (Q-2), R ^b1 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. It is a group. k4 is an integer of 0-7. If R ^b1 is plural, the plurality of R ^b1 may be the same or different, and plural R ^b1 may represent a constructed ring aligned with each other. R ^b2 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. k5 is an integer of 0-6. If R ^b2 is plural, the plurality of R ^b2 may be the same or different, and plural R ^b2 may represent a keyed configured ring structure. t is an integer of 0-3.
In the above formula (Q-3), R ^c1 and R ^c2 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 6 12 aromatic hydrocarbon group, or an -OSO ₂ -R ^R or _-SO 2 -R ^S, or two or more are combined with each other configured ring of these groups. R ^R and R ^S are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k6 and k7 are each independently an integer of 0 to 5. R ^{c1, R} c2, ^R when ^R and ^{R S} is plural respective plurality of ^{R c1,} R c2, ^{R R} and ^{R S} may have respectively the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^{a1 to} R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include a methyl group, an ethyl group, an n-propyl group, and n-butyl. Groups and the like.
Examples of the unsubstituted branched alkyl group represented by R ^{a1 to} R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include an i-propyl group, an i-butyl group, a sec-butyl group, Examples include t-butyl group.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^{a1 to} R ^a3 , R ^c1, and R ^c2 include aryl groups such as phenyl group, tolyl group, xylyl group, mesityl group, and naphthyl group; benzyl group And aralkyl groups such as a phenethyl group.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^b1 and R ^b2 include a phenyl group, a tolyl group, and a benzyl group.

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

R ^{a1 to} R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, and an unsubstituted monovalent aromatic hydrocarbon group. , —OSO ₂ —R ″ and —SO ₂ —R ″ are preferred, fluorinated alkyl groups, unsubstituted monovalent aromatic hydrocarbon groups are more preferred, and fluorinated alkyl groups are more preferred. R ″ is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As k1, k2, and k3 in the formula (Q-1), integers of 0 to 2 are preferable, 0 or 1 is more preferable, and 0 is more 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 more preferable. k5 is preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0.
As k6 and k7 in the formula (Q-3), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is more preferable.

Among these, the monovalent radiation-sensitive onium cation represented by Q ⁺ is preferably a sulfonium cation, more preferably a cation represented by the formula (Q-1), and further a triphenylsulfonium cation. preferable.

Examples of the monovalent organic oxoacid anion represented by Y ⁻ include a sulfonate anion, a carboxylate anion, an organic phosphate anion, and an organic phosphonate anion. Of these, sulfonate anions are preferred.

  As said sulfonate anion, the anion represented by a following formula (Y-1) is preferable.

In the formula (Y-1), R ^a 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 ^b is a fluorinated alkanediyl group having 1 to 10 carbon atoms.

The “number of ring members” in ^Ra refers to the number of atoms constituting the ring of the alicyclic structure and the aliphatic heterocyclic structure, and in the case of a polycyclic alicyclic structure and a polycyclic aliphatic heterocyclic structure, The number of atoms that make up the ring.

Examples of the monovalent group containing an alicyclic structure having 6 or more ring members represented by ^Ra above include:
A monocyclic cycloalkyl group such as a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cyclododecyl group;
A monocyclic cycloalkenyl group such as a cyclooctenyl group and a cyclodecenyl group;
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
And polycyclic cycloalkenyl groups such as a norbornenyl group and a tricyclodecenyl group.

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

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

R ^a is preferably ^a monovalent group containing an alicyclic structure having 9 or more ring members, or a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members, such as an adamantyl group or a hydroxyadamantyl group. , A norbornanelactone-yl group, and a 5-oxo-4-oxatricyclo [4.3.1.1 ^3,8 ] undecan-yl group are more preferable, and an adamantyl group is more preferable.

Examples of the fluorinated alkanediyl group having 1 to 10 carbon atoms represented by R ^b above include one of 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 include groups in which the above 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 More preferred are fluorinated alkanediyl groups, 1,1-difluoromethanediyl group, 1,1-difluoroethanediyl group, 1,1,3,3,3-pentafluoro-1,2-propanediyl group, 1,1 1,2,2-tetrafluoroethanediyl group, 1,1,2,2-tetrafluorobutanediyl group, and 1,1,2,2-tetrafluorohexanediyl group are more preferable.

  Examples of the compound (6) include compounds represented by the following formulas (6-1) to (6-13) (hereinafter also referred to as “compounds (6-1) to (6-13)”). Can be mentioned.

In the above formulas (6-1) to (6-13), Q ⁺ has the same meaning as in the above formula (6).

  Of these, the compound (6-2) is preferable.

The content of the [C] acid generator is preferably 1 part by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the polymer [A] when the [C] acid generator is a [C] acid generator. 3 to 50 parts by mass is more preferable, 5 to 40 parts by mass is further preferable, and 10 to 30 parts by mass is particularly preferable. [C] By making content of an acid generator into the said range, the sensitivity of the said radiation sensitive resin composition, LWR performance, and resolution can further be improved. [C] 1 type (s) or 2 or more types can be used for an acid generator.
<[D] Acid diffusion controller>
[D] The acid diffusion controller is a component that controls the diffusion phenomenon of the acid generated from the [C] acid generator and the like in the resist film by exposure and suppresses an undesirable chemical reaction in the unexposed area. When the radiation sensitive resin composition contains the [D] acid diffusion controller, the storage stability of the resulting radiation sensitive resin composition is further improved, and the resolution as a resist is further improved. In addition, it is possible to suppress a change in the line width of the resist pattern due to a change in the holding time from exposure to development processing, and a composition having extremely excellent process stability can be obtained. As the inclusion form of the [D] acid diffusion controller in the radiation-sensitive resin composition, even in the form of a compound described later (hereinafter referred to as “[D] acid diffusion controller” as appropriate), as a part of the polymer Either the built-in form or both forms may be used.

  [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 such as n-pentylamine; di (cyclo) alkylamines such as di-n-pentylamine; tri (cyclo) alkylamines such as tri-n-pentylamine; Substituted alkylanilines or derivatives thereof; ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylether, 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, -(4-aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-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, 2-quinoxa Linol, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ′, N ″ N ″ -pentamethyldiethylenetriamine, triethanolamine and the like can be mentioned. Among these, tri (cyclo) alkylamines are preferable, and tri-n-pentylamine is more preferable.

  Examples of amide group-containing compounds include Nt-butoxycarbonyl group-containing amino compounds, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, Examples thereof include benzamide, pyrrolidone, N-methylpyrrolidone, 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, quinosaline, purine, pyrrolidine, piperidine, N- (t-amyloxycarbonyl) -4-hydroxypiperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, N- (t-butoxycarbonyl) -2-hydroxymethylpyrrolidine, 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- ( N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, N- (t-butoxycarbonyl) -2-phenylbenzimidazole and the like. It is done. Among these, N- (t-amyloxycarbonyl) -4-hydroxypiperidine, N- (t-butoxycarbonyl) -2-hydroxymethylpyrrolidine, N- (t-butoxycarbonyl) -2-phenylbenzimidazole, 2 4,5-triphenylimidazole is preferred.

  Further, as the [D] acid diffusion control agent, a photodisintegratable base that is exposed to light and generates a weak acid by exposure can also be used. This photodegradable base exhibits a high acid capturing function by an anion in the unexposed area and functions as a quencher, and captures the acid diffusing from the exposed area, while the proton generated in the exposed area binds to the anion. The capture function disappears. That is, since it functions as a quencher only in the unexposed area, the contrast of the deprotection reaction is improved, and as a result, the resolution and LWR performance of the radiation-sensitive resin composition can be further improved. Examples of the photodegradable base include onium salt compounds having radiation sensitivity. Examples of the onium salt compound having radiation sensitivity include a sulfonium salt represented by the following formula (9-1), an iodonium salt represented by the following formula (9-2), and the like.

The formula (9-1) and formula ^(9-2), R 31 ^{to R 35} each independently represent a hydrogen atom, an alkyl group, an alkoxy group, hydroxy group, is a halogen atom or _-SO 2 -R ^E . R ^E is an alkyl group, a cycloalkyl group, an alkoxy group or an aryl group. E ^- and ^G - ^{is, OH -, R α -COO -} , R F -SO 2 -N - -R α, R α -SO 3 - it is an anion represented by or the following formula (9-3). ^Rα is a linear or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms. Some or all of the hydrogen atoms of the alkyl group, cycloalkyl group, aryl group and aralkyl group may be substituted. R ^F is a linear or branched alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent. Some or all of the hydrogen atoms of the alkyl group and cycloalkyl group may be substituted with fluorine atoms. However, when E ⁻ and G ⁻ are R ^α —SO ₃ ^— , a fluorine atom is not bonded to a carbon atom to which SO ₃ ^— is bonded.

In the above formula (9-3), R ^β represents 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 carbon atom. -12 linear or branched alkoxy groups. u is an integer of 0-2.

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

  Among these, triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate are preferable.

  [D] The content of the acid diffusion controller is 0 to 10 parts by mass with respect to 100 parts by mass of the polymer [A] when the [D] acid diffusion controller is a [D] acid diffusion controller. Is preferable, and 0.5 to 7 parts by mass is more preferable. [D] By making content of an acid diffusion control agent into the said range, the LWR performance and resolution of the said radiation sensitive resin composition can further be improved. [D] The acid diffusion controller may be used alone or in combination of two or more.

<[E] solvent>
The radiation-sensitive resin composition usually contains an [E] solvent. [E] The solvent is not particularly limited as long as it can dissolve or disperse the [A] polymer, the [B] organic compound, the [C] acid generator and the optional component. [E] Examples of the solvent include alcohol solvents, ether solvents, ketone organic solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

As an alcohol solvent, for example,
Methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert- Pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, 4-methyl-2-pentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2- Ethylhexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec- Descriptor decyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methyl cyclohexanol, 3,3,5-trimethyl cyclohexanol, benzyl alcohol, mono-alcohol solvents such as 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, and polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

As an ether solvent, for example,
Dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ether, dibutyl ether, diisobutyl ether, tert-butyl-methyl ether, tert-butyl ethyl ether, tert-butyl propyl ether, di-tert-butyl ether, Dipentyl ether, diisoamyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, cyclopentyl ethyl ether, cyclohexyl ethyl ether, cyclopentyl propyl ether, cyclopentyl-2-propyl ether, cyclohexyl propyl ether, cyclohexyl-2-propyl ether, cyclopentyl butyl ether, cyclopentyl- tert-butyl ether, cyclohex Butyl ether, cyclohexyl -tert- butyl ether, anisole, diethyl ether, chain ether solvent diphenyl ether;
Examples thereof include cyclic ether solvents such as tetrahydrofuran and dioxane.

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-n-amyl ketone, ethyl-n-butyl ketone, methyl-n- Chain ketone solvents such as hexyl ketone, di-iso-butyl ketone, trimethylnonanone, 2,4-pentanedione, acetonyl acetone, acetophenone;
Examples thereof include cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and methylcyclohexanone.

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

Examples of ester solvents 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, 3-methoxybutyl acetate, methyl pentyl acetate Acetate solvents such as 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, glycol diacetate, and methoxytriglycol acetate;
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 acetate Polyhydric alcohol partial ether acetate solvents such as ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether;
Ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, phthalic acid Carboxylate solvents other than acetic acid such as dimethyl, diethyl phthalate, methyl acetoacetate, ethyl acetoacetate;
Lactone solvents such as γ-butyrolactone and γ-valerolactone;
Examples thereof include carbonate solvents such as diethyl 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.

  Among these, ester solvents and ketone solvents are preferable, polyhydric alcohol partial ether acetate solvents and cyclic ketone solvents are more preferable, and propylene glycol monomethyl ether acetate and cyclohexanone are more preferable. [E] The solvent may be used alone or in combination of two or more.

<Other optional components>
The radiation-sensitive resin composition may contain, as other optional components, for example, a fluorine atom-containing polymer, a surfactant, an alicyclic skeleton-containing compound, a sensitizer, and the like. The radiation-sensitive resin composition may contain one or more other optional components.

(Fluorine atom-containing polymer)
The radiation sensitive resin composition may further contain a fluorine atom-containing polymer (except for those corresponding to the [A] polymer). When the radiation-sensitive resin composition contains a fluorine atom-containing polymer, when the resist film is formed, the distribution is unevenly distributed near the resist film surface due to the oil-repellent characteristics of the fluorine atom-containing polymer in the resist film. It is possible to prevent the acid generator, the acid diffusion controller and the like from being eluted into the immersion medium during immersion exposure. Further, due to the water-repellent characteristics of this fluorine atom-containing 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. Thus, the said radiation sensitive resin composition can form the resist film suitable for an immersion exposure method by further containing a fluorine atom containing polymer.

  The fluorine atom-containing polymer is not particularly limited as long as it is a polymer having a fluorine atom, but the fluorine atom content (% by mass) is higher than the [A] polymer of the radiation-sensitive resin composition. Is preferred. Examples of the fluorine atom-containing polymer include 1,1,1,3,3,3-hexafluoro-2-propyl (meth) acrylate, 1,1-difluoro-1-ethoxycarbonylbutan-2-yl ( Examples thereof include those having a structural unit derived from (meth) acrylate or the like containing a fluorine atom such as (meth) acrylate.

  As content of the said fluorine atom containing polymer, 0.1 mass part-20 mass parts are preferable with respect to 100 mass parts of [A] polymers, 0.5 mass part-15 mass parts are more preferable, 1 More preferred is 10 parts by mass.

(Surfactant)
Surfactants have the effect of improving coatability, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. Nonionic surfactants such as stearate; commercially available products include KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, Tochem Products), MegaFuck F171, F173 (above, DIC), Florard FC430, FC431 (above, Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, Asahi Glass) It is done.
As content of the said surfactant, it is 2 mass parts or less normally with respect to 100 mass parts of [A] polymers.

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

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

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

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

<Method for preparing radiation-sensitive resin composition>
The radiation sensitive resin composition includes, for example, [A] polymer, [B] organic compound, [C] acid generator, [D] acid diffusion controller, [E] solvent, etc. as required. It can be prepared by mixing in proportions. The radiation-sensitive resin composition is preferably filtered after mixing with, for example, a filter having a pore size of about 0.2 μm. As solid content concentration of the said radiation sensitive resin composition, 0.1 mass%-50 mass% are preferable, 0.5 mass%-30 mass% are more preferable, 1 mass%-20 mass% are more preferable.

<Resist pattern formation method>
The resist pattern forming method is:
A step of forming a resist film (hereinafter also referred to as a “resist film forming step”),
A step of exposing the 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”).
With
The resist film is formed from the radiation sensitive resin composition.

  As the radiation used in the exposure step, EUV, X-ray, and EB are preferable.

According to the resist pattern forming method, since the radiation sensitive resin composition described above is used, it is possible to form a resist pattern with a small LWR and a high resolution while exhibiting high sensitivity.
Hereinafter, each step will be described.

[Resist film forming step]
In this step, a resist film is formed from the radiation sensitive resin composition. Examples of the substrate on which the resist film is formed include conventionally known ones such as a silicon wafer, silicon dioxide, and a wafer coated with aluminum. Further, for example, an organic or inorganic 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 application method include spin coating (spin coating), cast coating, roll coating, and the like. After application, pre-baking (PB) may be performed as needed to volatilize the solvent in the coating film. As PB temperature, it is 60 to 140 degreeC normally, and 80 to 120 degreeC is preferable. The PB time is usually 5 seconds to 600 seconds, and preferably 10 seconds to 300 seconds. The thickness of the resist film to be formed is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

  In the case of immersion exposure, a protective film may be provided on the formed resist film. As a protective film for immersion, a solvent-removable protective film that peels off with a solvent before the developing step (see, for example, JP-A-2006-227632), a developer-removable protective film that peels simultaneously with development in the developing step ( For example, any of WO 2005-069076 and WO 2006-035790 may be used. However, from the viewpoint of throughput, it is preferable to use a developer peeling type immersion protective film.

[Exposure process]
In this step, the resist film formed in the resist film forming step is exposed by irradiating with radiation, for example, through a photomask or the like (in some cases through an immersion medium such as water). Examples of radiation used for exposure include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, EUV, X-rays and γ rays; charged particle beams such as EB and α rays, etc., depending on the line width of the target pattern. Can be mentioned. Among these, far ultraviolet rays, EUV (13.5 nm), X-rays, and EB are preferable, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), EUV, X-ray, and electron beam are more preferable. EUV, X-ray and EB are more preferable, and EUV is particularly preferable. When EUV, X-rays, and EB are used as radiation, the benefit of obtaining the sensitivity improvement effect of the present invention is more preferable.

  When exposure is performed by immersion exposure, examples of the immersion liquid to be used include water and a fluorine-based inert liquid. 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. In the case of excimer laser light (wavelength 193 nm), it is preferable to use water from the viewpoints of availability and easy handling in addition to the above-described viewpoints. When water is used, an additive that reduces the surface tension of water and increases the surface activity may be added in a small proportion. This additive is preferably one that does not dissolve the resist film on the wafer and can ignore the influence on the optical coating on the lower surface of the lens. The water used is preferably distilled water.

  After the exposure, post-exposure baking (PEB) is performed, and in the exposed part of the resist film, the acid-dissociable group of the [A] polymer is dissociated by the acid generated from the [C] acid generator by exposure. Is preferably promoted. By this PEB, the difference in solubility in the developer between the exposed part and the unexposed part becomes larger. As PEB temperature, it is 50 to 180 degreeC normally, and 80 to 130 degreeC is preferable. The PEB time is usually 5 seconds to 600 seconds, and preferably 10 seconds to 300 seconds.

[Development process]
In this step, the resist film exposed in the exposure step is developed. Thereby, a predetermined resist pattern can be formed. After development, it is common to wash with water or a rinse solution such as alcohol and then dry.

As a developer used for the above development,
In the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine , Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4 .3.0] -5 aqueous solution in which at least one alkaline compound such as 5-nonene is dissolved. Among these, a TMAH aqueous solution is preferable, and a 2.38 mass% TMAH aqueous solution is more preferable.
In the case of organic solvent development, organic solvents such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, etc., or solvents containing organic solvents can be mentioned. As said organic solvent, 1 type (s) or 2 or more types of the solvent enumerated as [E] solvent of the above-mentioned radiation sensitive resin composition are mentioned, for example. Among these, ester solvents and ketone solvents are preferable. As the ester solvent, an acetate solvent is preferable, and n-butyl acetate is more preferable. As a ketone solvent, a chain ketone is preferable and 2-heptanone is more preferable. As content of the organic solvent in a developing solution, 80 mass% or more is preferable, 90 mass% or more is more preferable, 95 mass% or more is further more preferable, 99 mass% or more is especially preferable. Examples of components other than the organic solvent in the developer include water and silicone oil.

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

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The measuring method of various physical property values is shown below.

[Mw, Mn and Mw / Mn]
Using GPC columns (two "G2000HXL", one "G3000HXL", one "G4000HXL" from Tosoh Corporation), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, sample concentration: 1.0 mass%, sample Injection amount: 100 μL, column temperature: 40 ° C., detector: measured by GPC using monodisperse polystyrene as a standard under the analysis conditions of a differential refractometer. The degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

[ ¹³ C-NMR analysis]
Using a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.), deuterated chloroform was used as a measurement solvent, and analysis for determining the content ratio (mol%) of each structural unit in each polymer was performed.

<[A] Synthesis of polymer>
[A] Monomers used for polymer synthesis are shown below.

[Synthesis Example 1] (Synthesis of polymer (A-1))
55.0 g (65 mol%) of the compound (M-1) and 45.0 g (35 mol%) of the compound (M-2), 4 g of AIBN as a radical polymerization initiator, and 1 g of t-dodecyl mercaptan were mixed with propylene glycol monomethyl. After dissolving in 100 g of ether, polymerization was carried out for 16 hours while maintaining the reaction temperature at 70 ° C. in a nitrogen atmosphere. After completion of the polymerization reaction, the polymerization reaction solution was dropped into 1,000 g of n-hexane, and the produced polymer was coagulated and purified. Next, 150 g of propylene glycol monomethyl ether was added again to the polymer obtained above, 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 and solidified, and the resulting white powder was filtered off at 50 ° C. It was dried for 17 hours to obtain a white powdery polymer (A-1) (yield 65.7 g, yield 77%). Mw of the polymer (A-1) was 10,000, and Mw / Mn was 1.90. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from p-hydroxystyrene and (M-2) were 65.4 mol% and 34.6 mol%, respectively.

<Preparation of radiation-sensitive resin composition>
The [B] organic compound, [C] acid generator, [D] acid diffusion controller and [E] solvent used for the preparation of the radiation sensitive resin composition are shown below.

[[B] Organic compound]
B-1 to B-9: Compounds represented by the following formulas (B-1) to (B-9)

[[C] acid generator]
C-1: Triphenylsulfonium 2- (adamantan-1-ylcarbonyloxy) -1,1,3,3,3-pentafluoropropane-1-sulfonate (compound represented by the following formula (C-1))

[[D] Acid diffusion controller]
D-1: Triphenylsulfonium 10-camphor-sulfonate

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

[Example 1]
[A] 100 parts by mass of (A-1) as a polymer, [B] 30 mol% of (B-1) as an organic compound (mol% relative to 100 mol% of [C] acid generator), [C] acid (C-1) 20 parts by mass as a generator, (D-1) 3.6 parts by mass as an acid diffusion control agent, and (E-1) 4,280 parts by mass as an [E] solvent, and (E-2) 1,830 parts by mass were blended, and the resulting mixture was filtered through a membrane filter having a pore size of 0.2 μm to prepare a radiation sensitive resin composition (J-1).

[Examples 2 to 9]
In Example 1, (B-2) to (B-9) were used instead of (B-1) as the [B] organic compound, in the same manner as in Example 1, except that the radiation sensitive resin composition ( J-2) to (J-9) were prepared.

[Comparative Example 1]
In Example 1, the radiation sensitive resin composition (CJ-1) was prepared like Example 1 except not using the [B] organic compound.

<Formation of resist pattern>
Each radiation sensitive resin composition was applied to the surface of an 8-inch silicon wafer using a spin coater (“CLEAN TRACK ACT8” manufactured by Tokyo Electron Ltd.), PB was performed at 90 ° C. for 60 seconds, and then 23 The resist film with a film thickness of 50 nm was formed by cooling at 0 ° C. for 30 seconds. 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 100 ° C. for 60 seconds. Thereafter, development was performed at 23 ° C. for 30 seconds using a 2.38 mass% TMAH aqueous solution as an alkaline developer, washed with water, and dried to form a positive resist pattern.

<Evaluation>
By measuring according to the following method about the formed resist pattern, the sensitivity, LWR performance, and resolution of the radiation sensitive resin composition were evaluated. The evaluation results are shown in Table 1 below. “*” In Comparative Example 1 in Table 1 indicates that it is a criterion for evaluation. A scanning electron microscope (Hitachi High-Technologies “S-9380”) was used for measuring the resist pattern.

[sensitivity]
When forming the resist pattern, the exposure amount formed in a one-to-one line-and-space with a line width of 150 nm was taken as the optimum exposure amount, and this optimum exposure amount was taken as the sensitivity. The sensitivity indicates that the smaller the value, the higher the sensitivity. When the sensitivity is improved by 10% or more compared to Comparative Example 1 (meaning that the value of the optimum exposure amount is 90% or less compared with Comparative Example 1), “good” is less than 10%. If it was an improvement, it was evaluated as “equivalent”.

[LWR performance]
The line width of the resist pattern was measured at 50 arbitrary points using the above scanning electron microscope, and a 3-sigma value was obtained from the distribution of the measured values, and this was defined as LWR performance. The LWR performance indicates that the smaller the value, the smaller the line width wobble of the resist pattern. The LWR performance is 10% or more when the improvement in LWR performance is 10% or more (meaning that the value of LWR is 90% or less compared with Comparative Example 1). If it was less than an improvement, it was evaluated as “equivalent”.

[Resolution]
The dimension of the minimum resist pattern that can be resolved at the optimum exposure dose was measured, and this dimension was defined as the resolution. The resolution indicates that the smaller the value, the better the fine pattern can be formed. The resolution is “good” when the resolution is improved by 10% or more compared to the case of Comparative Example 1 (which means that the minimum resist pattern dimension is 90% or less as compared with Comparative Example 1). When the improvement was less than 10%, it was evaluated as “equivalent”.

  As is apparent from the results in Table 1, it can be seen that the radiation-sensitive resin compositions of the examples are excellent in sensitivity and excellent in LWR performance and resolution. It is known that the EUV exposure has the same tendency as the electron beam exposure. According to the radiation-sensitive resin compositions of the examples, even in the case of EUV exposure, the sensitivity, LWR performance and resolution are improved. It is estimated that it is excellent.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern with low LWR and high resolution can be formed while exhibiting high sensitivity. Therefore, they can be suitably used for forming a fine resist pattern in the lithography process of various electronic devices such as semiconductor devices and liquid crystal devices.

Claims (6)

A polymer having an acid dissociable group,
Radiation sensitivity containing at least one organic compound selected from the group consisting of compounds represented by the following formulas (1) and (3) to (5), and an acid generator that generates an acid by the action of radiation. Resin composition.

(In the formula (1), ^{R 1} is ^.R 2 to R ⁶ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms are each independently a monovalent organic hydrogen atom or a C 1-20 R ³ and R ⁴ or R ⁵ and R ⁶ may be combined with each other to form a ring structure having 4 to 20 ring members together with the carbon atom to which they are bonded.
In the formula (3), Ar ^{1 to} Ar ⁵ are each independently a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms or a substituted or unsubstituted ring member having 4 to 20 ring members. A valent aromatic heterocyclic group. R ^{21 to} R ²⁵ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.
In the formula (4), Ar ^{11 to} Ar ¹⁶ are each independently a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms or a substituted or unsubstituted ring member having 4 to 20 ring members. A valent aromatic heterocyclic group. Ar ¹³ and Ar ¹⁶ may be combined with each other to form a ring structure having 4 to 20 ring members together with the carbon atom to which they are bonded.
In formula (5), Ar ^{21 to} Ar ²⁴ each independently represent a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms or a substituted or unsubstituted ring member having 1 to 4 ring members. A valent aromatic heterocyclic group. Ar ²¹ and Ar ²² or Ar ²³ and Ar ²⁴ may be combined with each other to form a ring structure having 4 to 20 ring members together with the carbon atom to which they are bonded. ) The radiation sensitive resin composition according to claim 1, wherein the acid generator is represented by the following formula (6).

(In Formula (6), Q ⁺ is a monovalent radiation-sensitive onium cation. Y ⁻ is a monovalent organic oxoacid anion.) The radiation sensitive resin composition of Claim 1 or Claim 2 by which the acid dissociable group of the said polymer is represented by following formula (7).

(In formula (7), R ^p1 is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R ^p2 and R ^p3 are each independently selected. An alicyclic ring having 3 to 20 ring members which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 4 to 20 carbon atoms, or these groups are combined with each other and bonded to carbon atoms Represents the structure. * Indicates the bonding site to the polar group of the polymer.) The radiation-sensitive resin composition according to claim 1 , wherein the radiation is extreme ultraviolet (EUV), X-ray or electron beam (EB). Forming a resist film;
A step of exposing the resist film, and a step of developing the exposed resist film,
The resist pattern formation method which forms the said resist film with the radiation sensitive resin composition of any one of Claims 1-4 . The resist pattern forming method according to claim 5 , wherein the radiation used in the exposure step is extreme ultraviolet (EUV), X-ray, or electron beam (EB).