JP2017167371A - Method for forming negative resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a negative resist pattern by which a resist pattern with fewer development defects can be formed while maintaining good water repellency on a surface of an overlay film.SOLUTION: The method for forming a negative resist pattern includes the steps of: forming a resist film by using a radiation-sensitive resin composition; forming an overlay film from an overlay film forming composition on one surface of the resist film; subjecting the resist film with the overlay film formed thereon to immersion exposure; and developing the resist film subjected to the immersion exposure with a developer containing an organic solvent. The radiation-sensitive resin composition comprises a polymer containing a fluorine atom, a polymer having an acid dissociable group, and a radiation-sensitive acid generator. The overlay film forming composition comprises [J] a polymer, and preferably satisfies at least one in the group consisting of the following (i) and (ii): (i) the overlay film forming composition further contains an acid diffusion inhibition compound; and (ii) the [J] polymer contains a structural unit having an acid diffusion inhibition group.SELECTED DRAWING: None

Description

  The present invention relates to a negative resist pattern forming method.

  Along with miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, miniaturization of resist patterns in a lithography process is required. At present, a fine resist pattern having a line width of about 90 nm can be formed using, for example, an ArF excimer laser. However, in the future, a finer resist pattern will be required.

  In response to the above requirements, as a technique for improving the resolution of a conventional chemically amplified radiation-sensitive resin composition without increasing the number of processes using an existing apparatus, a negative polarity is obtained by using an organic solvent having a polarity lower than that of an alkaline aqueous solution as a developer. A technique for forming a mold resist pattern is known (see Japanese Patent Application Laid-Open No. 2000-199953). In other words, when forming a resist pattern using an alkaline aqueous solution as a developer, it is difficult to form a fine resist pattern due to poor optical contrast. Since the optical contrast can be increased, a finer resist pattern can be formed.

  Also in the development using such an organic solvent, immersion exposure is used to form a finer resist pattern. In this immersion exposure, an upper layer film (top coat) is formed on the resist film. (See JP 2008-309878).

  However, when an organic solvent is used as a developer as described above, when forming a resist pattern, a bridge defect in which a part of the resist pattern is connected, and the solubility of the resist film and the upper layer film in the developer is high. There is an inconvenience that development defects such as disconnection defects considered to be caused occur.

  It is conceivable to change the resist composition to increase the hydrophobicity of the resist film for such inconvenience. However, such changes include DOF (Depth Of Focus), CDU (Critical Dimension Uniformity), and LWR (Line Width Roughness) performance. This tends to cause a reduction in lithography characteristics and the like, and a good resist pattern cannot be formed.

JP 2000-199953 A JP 2008-309878 A

  The present invention has been made based on the above circumstances, and its purpose is to form a resist pattern having excellent lithography characteristics and few development defects while maintaining good water repellency on the surface of the upper layer film. It is an object of the present invention to provide a negative resist pattern forming method capable of achieving the above.

  The invention made in order to solve the above problems includes a step of forming a resist film using a radiation-sensitive resin composition (hereinafter also referred to as “resist film forming step”), an upper layer film on one surface of the resist film A step of forming an upper layer film with the composition for forming (hereinafter also referred to as “upper layer film forming step”), a step of immersion exposure of the resist film on which the upper layer film is formed (hereinafter also referred to as “immersion exposure step”). And a step of developing the immersion-exposed resist film with a developer containing an organic solvent (hereinafter also referred to as “development step”), and the radiation-sensitive resin composition contains a fluorine atom [ A] a negative resist pattern forming method comprising a polymer, a [B] polymer having an acid-dissociable group, and a [C] radiation-sensitive acid generator.

  Here, the “organic group” refers to a group containing at least one carbon atom.

  According to the negative resist pattern forming method of the present invention, a negative resist pattern is formed that can form a resist pattern having excellent lithography characteristics and few defects while maintaining good water repellency on the surface of the upper layer film. be able to. Therefore, the negative resist pattern forming method can be suitably used for pattern formation in the field of semiconductor devices and the like that will require further miniaturization and higher quality in the future.

<Negative resist pattern forming method>
The negative resist pattern forming method of the present invention includes a resist film forming step, an upper layer film forming step, an immersion exposure step, and a developing step. In the negative resist pattern forming method, the radiation-sensitive resin composition (Z) is used as the radiation-sensitive resin composition, and the upper-layer film-forming composition (S) is used as the upper-layer film-forming composition.

  According to the negative resist pattern forming method, since the radiation-sensitive resin composition (Z) and the upper layer film forming composition (S) are used, the water repellency of the upper layer film surface can be increased and development defects can be improved. A small number of resist patterns can be formed. Hereinafter, each process of the said negative resist pattern formation method, a radiation sensitive resin composition (Z), and the composition for upper layer film formation (S) are demonstrated.

[Resist film forming step]
In this step, a resist film is formed. The resist film is formed on a substrate using the radiation sensitive resin composition (Z). As a substrate to be used, a silicon wafer, a silicon wafer coated with aluminum, and the like are usually mentioned. Further, in order to maximize the characteristics of the resist film to be formed, an organic or inorganic antireflection film described in, for example, Japanese Patent Publication No. 6-12458 is formed on the surface of the substrate in advance. Is preferred.

<Radiation sensitive resin composition (Z)>
The radiation sensitive resin composition (Z) contains the [A] polymer containing a fluorine atom. The radiation sensitive resin composition (Z) is a polymer having a smaller fluorine atom content than the [A] polymer, and is a polymer having an acid dissociable group [B] polymer and [C]. It is preferable to contain a radiation sensitive acid generator. Furthermore, the said radiation sensitive resin composition may contain the other arbitrary component in the range which does not impair the effect of this invention.

[[A] polymer]
[A] A polymer is a polymer containing a fluorine atom. [A] The polymer preferably has the following structural unit (I). [A] In addition to the structural unit (I), the polymer [A] has any one of the structural units in the polymer [B] to be described later from the viewpoint of improving the development defect suppression of the radiation-sensitive resin composition. It is preferable. The radiation-sensitive resin composition contains the [A] polymer, so that when the resist film is formed, the distribution is unevenly distributed on the resist film surface due to the oil-repellent characteristics of the [A] polymer. There is a tendency, and it is possible to suppress the acid generator, the acid diffusion controller, and the like from being eluted into the immersion liquid during the immersion exposure. Moreover, also in electron beam exposure or EUV exposure, the development defect suppression property of a resist film can be improved by the water-repellent characteristic of [A] polymer. Thus, when the said radiation sensitive resin composition contains a [A] polymer, the resist film suitable for liquid immersion exposure, electron beam exposure, EUV exposure, etc. can be formed.

  The negative resist pattern forming method includes a step of forming a resist film using a radiation sensitive resin composition (Z) containing a [A] polymer containing fluorine atoms, and an upper layer film on one surface of the resist film. The reason why the above effect is achieved by having the above-described configuration such as the step of forming the upper layer film with the forming composition (S) is not necessarily clear, but can be presumed as follows, for example. That is, the [A] polymer contained in the radiation-sensitive resin composition (Z) constituting the resist film contains a fluorine atom, which is characterized by the low surface free energy of the [A] polymer. The distribution tends to be unevenly distributed on the surface of the resist film, and the water repellency of the upper layer film formed on one surface of the resist film can be further enhanced by the oil repellency characteristic of the fluorine atom of the polymer [A]. Conceivable.

  [A] As a polymer, it is preferable that the mass content rate of a fluorine atom is larger than the [B] polymer in the said radiation sensitive resin composition. The [A] polymer has a higher mass content of fluorine atoms than the [B] polymer, so that the degree of uneven distribution described above is higher, and the resulting resist film surface has water repellency and elution suppression properties. Can be further improved.

[A] As a minimum of the mass content rate of the fluorine atom of a polymer, 1 mass% is preferred, 2 mass% is more preferred, 4 mass% is still more preferred, and 7 mass% is especially preferred. The upper limit of the total mass content is preferably 60% by mass, more preferably 40% by mass, and still more preferably 30% by mass. The mass content of fluorine atoms in the polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR spectrum measurement or the like.

  [A] The form of fluorine atoms in the polymer is not particularly limited, and may be bonded to any of the main chain, side chain and terminal, but is a structural unit containing a fluorine atom (hereinafter referred to as “structural unit (I)”). It is preferable to have (also called). [A] The polymer may have other structural units in addition to the structural unit (I). Examples of the other structural unit include a structural unit containing a polar group and a structural unit derived from a (meth) acrylic acid ester containing a non-dissociable monovalent alicyclic hydrocarbon group. Examples of the polar group include an alcoholic hydroxyl group, a carboxy group, a cyano group, a nitro group, and a sulfonamide group. Moreover, as an upper limit of the content rate of the said other structural unit with respect to all the structural units which comprise a [A] polymer, 90 mol% is preferable and 85 mol% is more preferable.

[Structural unit (I)]
The structural unit (I) is a structural unit represented by the following formula (F). [A] The fluorine atom content can be adjusted by having the structural unit (I) in the polymer.

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

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

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

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

The monovalent fluorine-cycloaliphatic hydrocarbon group having 4 to 20 carbon atoms represented by R ^e, for example monofluoromethyl cyclopentyl group, difluorocyclopentyl groups, perfluorocyclopentyl group, monofluoromethyl cyclohexyl group, difluorocyclopentyl groups Perfluorocyclohexylmethyl group, fluoronorbornyl group, fluoroadamantyl group, fluorobornyl group, fluoroisobornyl group, fluorotricyclodecyl group, fluorotetracyclodecyl group and the like.

Among these, as R ^e , a fluorinated chain hydrocarbon group is preferable, and 2,2,2-trifluoroethyl group, 1,1,1,3,3,3-hexafluoro-2-propyl group is preferable. The group is more preferable, and the 1,1,1,3,3,3-hexafluoro-2-propyl group is more preferable.

  As a content rate of structural unit (I), 10 mol%-100 mol% are preferable with respect to all the structural units which comprise a [A] polymer, 30 mol%-95 mol% are more preferable, 50 mol% -90 mol% is more preferable. By setting it as such a content rate, the fluorine atom content rate of a [A] polymer can be adjusted more appropriately.

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

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized, for example, by polymerizing monomers that give 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. These radical initiators can be used alone or in combination of two or more.

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

  As 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, more preferably 2,000 or more and 30,000 or less. Preferably, 2,500 or more and 20,000 or less are more preferable, and 3,000 or more and 15,000 or less are particularly preferable. [A] By making Mw of a polymer into the said range, the applicability | paintability and development defect inhibitory property of the said radiation sensitive resin composition improve. [A] If the Mw of the polymer is less than the lower limit, a resist film having sufficient heat resistance may not be obtained. [A] If the Mw of the polymer exceeds the above upper limit, the developability of the resist film may deteriorate.

  [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, more preferably from 1 to 2. .

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] polymer>
The [B] polymer is a polymer having a fluorine atom content smaller than that of the [A] polymer, and is a polymer having an acid dissociable group. [B] The polymer is usually a base polymer in the radiation-sensitive resin composition. The “base polymer” refers to a polymer that is a main component of the polymers constituting the resist pattern, and preferably occupies 50% by mass or more, more preferably 60% by mass or more.

  [B] The polymer is at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure and a sultone structure in addition to the structural unit containing the acid dissociable group (hereinafter also referred to as “structural unit (II)”). It is preferable to have a structural unit (III) containing a seed, and other structural units other than these structural units may be included. [B] The polymer may have one or more of these structural units.

[Structural unit (II)]
The structural unit (II) is a structural unit containing an acid dissociable group. In the radiation-sensitive resin composition, the [B] polymer has the structural unit (II), whereby sensitivity and resolution are improved, and as a result, lithography performance can be improved. The “acid-dissociable group” refers to a group that substitutes a hydrogen atom of a carboxy group, a hydroxy group, etc., and dissociates by the action of an acid.

Examples of the structural unit (II) include a structural unit represented by the following formula (4) (hereinafter also referred to as “structural unit (II-1)”). The group represented by —CR ⁵ R ⁶ R ⁷ in the formula (4) of the structural unit (II-1) is an acid dissociable group.

In said formula (4), R < ⁴ > is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y ′ is a single bond, a carbonyloxyalkanediyl group having 2 to 20 carbon atoms, a carbonyloxycycloalkanediyl group having 4 to 20 carbon atoms, a carbonyloxycycloalkanediyloxy group having 4 to 20 carbon atoms, or 6 to 6 carbon atoms. It is a 20 arene diyl group or a C7-20 carbonyloxyarene diyl group. R ⁵ is a hydrogen atom or a monovalent chain hydrocarbon group having 1 to 10 carbon atoms. R ⁶ and R ⁷ 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 carbonyloxyalkanediyl group having 2 to 20 carbon atoms represented by Y ′ include a carbonyloxymethanediyl group, a carbonyloxyethanediyl group, and a carbonyloxypropanediyl group.

Examples of the carbonyloxycycloalkanediyl group having 4 to 20 carbon atoms represented by Y ′ include a carbonyloxycyclopropanediyl group, a carbonyloxycyclobutanediyl group, a carbonyloxycyclopentanediyl group, and a carbonyloxycyclohexanediyl group. A monocyclic carbonyloxycycloalkanediyl group;
Examples thereof include a polycyclic carbonyloxycycloalkanediyl group such as a carbonyloxynorbornanediyl group, a carbonyloxyadamantanediyl group, a carbonyloxytricyclodecanediyl group, and a carbonyloxytetracyclododecanediyl group.

Examples of the carbonyloxycycloalkanediyloxy group having 4 to 20 carbon atoms represented by Y ′ include, for example, carbonyloxycyclopropanediyloxy group, carbonyloxycyclobutanediyloxy group, carbonyloxycyclopentanediyloxy group, carbonyloxycyclohexane Monocyclic carbonyloxycycloalkanediyloxy groups such as diyloxy groups;
Examples thereof include polycyclic carbonyloxycycloalkanediyloxy groups such as carbonyloxynorbornanediyloxy group, carbonyloxyadamantanediyloxy group, carbonyloxytricyclodecanediyloxy group, and carbonyloxytetracyclododecandiyloxy group.

Examples of the C6-20 arenediyl group represented by Y ′ include a benzenediyl group, a toluenediyl group, a xylenediyl group, a mesitylenediyl group, a naphthalenediyl group, and an anthracenediyl group.

Examples of the carbonyloxyarenediyl group having 6 to 20 carbon atoms represented by Y ′ include, for example, a carbonyloxybenzenediyl group, a carbonyloxytoluenediyl group, a carbonyloxyxylenediyl group, a carbonyloxymesityleneoxy group, and a carbonyloxynaphthalenediyl group. Group, carbonyloxyanthracenediyl group and the like.

  Y ′ is preferably a single bond, a carbonyloxyalkanediyl group having 2 to 20 carbon atoms, a carbonyloxycycloalkanediyloxy group having 4 to 20 carbon atoms, or an arenediyl group having 6 to 20 carbon atoms. An oxymethanediyl group, a polycyclic carbonyloxycycloalkanediyloxy group, and a benzenediyl group are more preferable, and a single bond and a carbonyloxymethanediyl group are more preferable.

R ⁴ is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (II).

Examples of the monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by R ⁵ , R ⁶ and R ⁷ include alkyl groups such as a methyl group, an ethyl group, an n-propyl group and an i-propyl group. ;
An alkenyl group such as an ethenyl group, a propenyl group, a butenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group, and butynyl group.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ⁵ , R ⁶ and R ⁷ include monocyclic alicyclic saturated hydrocarbon groups such as a cyclopentyl group and a cyclohexyl group;
Monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopentenyl group and cyclohexenyl group;
Polycyclic alicyclic saturated hydrocarbon groups such as norbornyl group, adamantyl group and tricyclodecyl group;
And polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group and a tricyclodecenyl group.

Examples of the alicyclic structure having 3 to 20 carbon atoms configured together with the carbon atom to which these groups are combined and bonded to each other include a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, a cyclo Monocyclic alicyclic saturated hydrocarbon structures such as octane structures;
And polycyclic alicyclic saturated hydrocarbon structures such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure.

  As the structural unit (II-1), structural units represented by the following formulas (4-1) to (4-5) (hereinafter referred to as “structural units (II-1-1) to (II-1-5)”). Are also preferred).

R < ⁴ > -R < ⁷ > is synonymous with the said Formula (4) in said formula (4-1)-(4-5). i and j are each independently an integer of 1 to 4.

  Examples of the structural units (II-1-1) to (II-1-5) include structural units represented by the following formulas.

In the above formula, ^{R 4} is as defined in the above formula (4).

  As the structural unit (II), a structural unit derived from 1-alkyl-monocyclic cycloalkane-1-yl (meth) acrylate, a structure derived from 2-alkyl-polycyclic cycloalkane-2-yl (meth) acrylate A structural unit derived from a unit, 2- (cycloalkane-yl) propan-2-yl (meth) acrylate, a structural unit derived from 1-alkyl-monocyclic cycloalkane-1-yloxycarbonylmethyl (meth) acrylate Preferably, a structural unit derived from 1-methylcyclopentan-1-yl (meth) acrylate, a structural unit derived from 1-i-propylcyclopentan-1-yl (meth) acrylate, 2- (adamantan-1-yl ) Structural unit derived from propan-2-yl (meth) acrylate, 2- (cyclohexane-1-yl) propyl Bread-2-yl (meth) structural units derived from acrylate, structural units derived from 1-ethyl-cyclopentane-1-yl oxycarbonyl methyl (meth) acrylate are more preferred.

  As a content rate of structural unit (II), 10 mol%-80 mol% are preferable with respect to all the structural units which comprise a [B] polymer, 20 mol%-75 mol% are more preferable, 30 mol% -70 mol% is further more preferable, and 35 mol%-60 mol% is especially preferable. By making the content rate of structural unit (II) into the said range, the lithography performance of the said radiation sensitive resin composition can be improved more. When the content ratio is less than the lower limit, the pattern formability of the radiation-sensitive resin composition may be lowered. When the said content rate exceeds the said upper limit, the adhesiveness to the board | substrate of a resist pattern may fall.

[Structural unit (III)]
The structural unit (III) is a structural unit containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. [B] The polymer can further adjust the solubility in the developer by further including the structural unit (III), and as a result, the lithography performance of the radiation-sensitive resin composition can be improved. . Moreover, the adhesiveness of the resist pattern formed from the said radiation sensitive resin composition and a board | substrate can be improved.

  Examples of the structural unit (III) containing a lactone structure include structural units represented by formulas (5-1-1) to (5-1-19) represented by the following formulas (hereinafter, “structural units (III) -1-1) to (III-1-19) ") as the structural unit (III) containing a cyclic carbonate structure, for example, the following formulas (5-2-1) to (5-2-2) 17) (hereinafter also referred to as “structural units (III-2-1) to (III-2-17)”) or the like includes the sultone structure as the structural unit (III), for example, Structural units represented by the following formulas (5-3-1) to (5-3-11) (hereinafter also referred to as “structural units (III-3-1) to (III-3-11)”) and the like Each is listed.

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

  As the structural unit (III), structural units (III-1-1), (III-1-2), (III-1-5), (III-1-7), (III-1-10), (III-1-13), (III-1-19), (III-2-1), and (III-3-1) are more preferable.

  As a content rate of the said structural unit (III), 80 mol% or less is preferable with respect to all the structural units in a [B] polymer, 10 mol%-70 mol% are more preferable, 20 mol%-60 mol% are 20 mol%. Further preferred. By making the content rate of structural unit (III) into the said range, the lithography performance of the said radiation sensitive resin composition can be improved more. Further, the adhesion between the obtained resist pattern and the substrate can be further improved.

  [B] The polymer may have other structural units in addition to the structural units (II) and (III). Examples of the other structural units include a structural unit having at least one selected from the group consisting of a hydroxy group, a ketonic carbonyl group, a cyano group, a carboxy group, a nitro group, and an amino group, tricyclodecyl (meth) acrylate, and the like. Examples thereof include a structural unit containing a non-acid dissociable alicyclic hydrocarbon group such as a structural unit derived therefrom. Among these, a structural unit having a hydroxy group is preferable, and a structural unit derived from 3-hydroxyadamantan-1-yl (meth) acrylate, 1-oxa-2-oxo-3-methylene-8-hydroxyspiro [4 , 5] A structural unit derived from decane is preferred. As a content rate of these structural units, 30 mol% or less is preferable and 20 mol% or less is more preferable.

  [B] The lower limit of the content of the polymer is preferably 1500 parts by mass, more preferably 2000 parts by mass, and still more preferably 2500 parts by mass with respect to 100 parts by mass of the [A] polymer. [B] The upper limit of the content of the polymer is preferably 9000 parts by mass, more preferably 7000 parts by mass, and still more preferably 4000 parts by mass with respect to 100 parts by mass of the polymer [A].

  Moreover, as content of [B] polymer, 70 mass% or more is preferable with respect to the total solid of the said radiation sensitive resin composition, 80 mass% or more is more preferable, 85 mass% or more is further more preferable. .

  The [B] polymer can be synthesized by the same method as the above-described [A] polymer.

  [B] 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, more preferably 2,000 or more and 30,000 or less. Preferably, 3,000 or more and 20,000 or less are more preferable, and 3,500 or more and 15,000 are particularly preferable. [B] By making Mw of a polymer into the said range, the applicability | paintability and development defect inhibitory property of the said radiation sensitive resin composition improve. [B] If the polymer Mw is less than the lower limit, a resist film having sufficient heat resistance may not be obtained. [B] If the Mw of the polymer exceeds the above upper limit, the developability of the resist film may be lowered.

  [B] 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, more preferably from 1 to 2. .

<[C] Radiation sensitive acid generator>
[C] The radiation-sensitive acid generator is a substance that generates an acid upon exposure. Since the acid-dissociable group of the [B] polymer and the like is dissociated by the generated acid to generate a carboxy group and the like, and the solubility of these polymers in the developer changes, the radiation-sensitive resin composition From the above, the inclusion form of the [C] radiation-sensitive acid generator in the radiation-sensitive resin composition capable of forming a resist pattern is a form of a low molecular compound as described later (hereinafter referred to as “[C ] A radiation-sensitive acid generator ", a form incorporated as part of the polymer, or both forms.

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

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

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

  [C] The radiation-sensitive acid generator is preferably a compound represented by the following formula (CC). [C] By making the radiation sensitive acid generator a compound represented by the following formula (CC), it is generated by exposure due to interaction with the polar structure of the [A] polymer or [B] polymer, etc. It is considered that the diffusion length of the acid in the resist film is appropriately shortened, and as a result, the lithography performance of the radiation sensitive resin composition can be further improved.

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

The “number of ring members” in R ^b1 refers to the number of atoms constituting the ring of the alicyclic structure and the aliphatic heterocyclic structure. In the case of the polycyclic alicyclic structure and the polycyclic aliphatic heterocyclic structure, The number of atoms that make up a polycycle.

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

Among these, R ^b1 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 hydroxyadamantyl group. Group, norbornanelactone-yl group, and 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 ^b2 include one or more hydrogen atoms of an alkanediyl group having 1 to 10 carbon atoms such as a methanediyl group, an ethanediyl group, and a propanediyl group. And a group in which is substituted with a fluorine atom.
Among these, SO ₃ ^- fluorinated alkane diyl group which has a fluorine atom to carbon atom is bonded to adjacent groups are preferred, SO ₃ ^- 2 fluorine atoms to the carbon atom adjacent to the group is attached 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.

The monovalent radiolytic onium cation represented by M ⁺ is a cation that decomposes upon exposure to exposure light. In the exposed portion, sulfonic acid is generated from protons generated by the decomposition of the radiolytic onium cation and the sulfonate anion. Examples of the monovalent radiolytic onium cation represented by M ⁺ include elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. And radiation-decomposable onium cations. Examples of the cation containing S (sulfur) as an element include a sulfonium cation and a tetrahydrothiophenium cation. Examples of the cation containing I (iodine) as an element include an iodonium cation. Among these, a sulfonium cation, a tetrahydrothiophenium cation, and an iodonium cation are preferable.

  [C] Examples of the radiation sensitive acid generator include compounds represented by the following formulas (CC-1) to (CC-17) (hereinafter referred to as “compounds (CC-1) to (CC-17)”). And the like).

  [C] Of these, the radiation-sensitive acid generator is preferably an onium salt compound, more preferably a sulfonium salt, and compounds (CC-1) to (CC-3) and compounds (CC-13) to ( CC-17) is more preferred.

  [C] The content of the radiation-sensitive acid generator is as follows. When the [C] radiation-sensitive acid generator is a [C] radiation-sensitive acid generator, the sensitivity and developability of the radiation-sensitive resin composition. From an improvement viewpoint, 10 mass parts-1000 mass parts are preferable with respect to 100 mass parts of [B] compounds, 30 mass parts-800 mass parts are more preferable, and 50 mass parts-500 mass parts are more preferable.

  Moreover, as content of [C] radiation sensitive acid generator, 0.1 mass part-30 mass parts are preferable with respect to 100 mass parts of [B] polymers, and 0.5 mass part-20 mass parts. Is more preferable, 1 to 15 parts by mass is further preferable, and 3 to 15 parts by mass is particularly preferable. [C] The radiation sensitive acid generator may be used alone or in combination of two or more.

<[D] solvent>
The radiation-sensitive resin composition usually contains a [D] solvent. [D] The solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the [A] compound, the [B] polymer, and the [C] radiation-sensitive acid generator contained as necessary.

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

As an alcohol solvent, for example,
C1-C18 aliphatic monoalcohol solvents such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcohol solvent having 3 to 18 carbon atoms such as cyclohexanol;
A C2-C18 polyhydric alcohol solvent such as 1,2-propylene glycol;
Examples thereof include C3-C19 polyhydric alcohol partial ether solvents such as propylene glycol monomethyl ether.

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

Examples of ketone solvents include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone (methyl-n-pentyl ketone), and ethyl-n-butyl ketone. Chain ketone solvents such as methyl-n-hexyl ketone, di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
2,4-pentanedione, acetonylacetone, acetophenone and the like can be mentioned.

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

Examples of ester solvents include:
Monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvents such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate;
lactone solvents such as γ-butyrolactone and δ-valerolactone;
Polycarboxylic acid diester solvents such as diethyl oxalate;
Examples thereof include carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene cartonate.

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

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

<Other optional components>
The said radiation sensitive resin composition may contain other arbitrary components other than said [A]-[D] component. Examples of the other optional components include [E] acid diffusion control agents, surfactants, alicyclic skeleton-containing compounds, and sensitizers. Each of these other optional components may be used alone or in combination of two or more.

[E] Acid Diffusion Control Agent [E] The acid diffusion control agent controls the diffusion phenomenon in the resist film of the acid generated from the [C] radiation sensitive acid generator upon exposure. As a result, there is an effect of suppressing an undesirable chemical reaction in the non-exposed region. Moreover, the storage stability of the obtained radiation sensitive resin composition further improves. Further, the resolution as a resist is further improved, and a change in the line width of the resist pattern due to a change in the holding time from exposure to development processing can be suppressed, and a radiation-sensitive resin composition excellent in process stability can be obtained. .

  [E] Examples of the acid diffusion controller include a compound represented by the following formula (EE-1) (hereinafter also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule ( Hereinafter, also referred to as “nitrogen-containing compound (II)”, compounds having three nitrogen atoms (hereinafter also referred to as “nitrogen-containing compound (III)”), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, etc. Is mentioned.

In the above formula (EE-1), R ^f1 , R ^f2 and R ^f3 are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, aryl group or aralkyl group. It is.

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

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

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

  Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. It is done.

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

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

  [E] As the acid diffusion controller, a photodisintegratable base that is a basic compound that is exposed to light and generates a weak acid can also be used. An example of a photo-disintegrating base is an onium salt compound that loses acid diffusion controllability by decomposition upon exposure. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (EE-2) and an iodonium salt compound represented by the following formula (EE-3).

In the formula (EE-2) and Formula ^{(EE-3), R 40} ~R 44 are each independently a hydrogen atom, an alkyl group, an alkoxy group, hydroxy group, a halogen atom or _-SO 2 -R ^C is there. R ^C is an alkyl group, a cycloalkyl group, an alkoxy group or an aryl group. Z ⁻ is OH ⁻ , R ⁵⁰ —COO ⁻ , R ^D —SO ₂ —N ⁻ —R ⁵⁰ , R ⁵⁰ —SO ₃ ^— or an anion represented by the following formula (EE-4). R ⁵⁰ and ^RD are each independently a monovalent organic group having 1 to 30 carbon atoms.

In the above formula (EE-4), R ⁴⁵ 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 monovalent organic group having 1 to 30 carbon atoms represented by R ⁵⁰ and ^RD include, for example, a monovalent hydrocarbon group having 1 to 30 carbon atoms, the carbon-carbon or bond side of the hydrocarbon group. A group containing a heteroatom-containing group at the terminal thereof, a group in which part or all of the hydrogen atoms of these groups are substituted with a substituent, and the like. The hydrocarbon group represented by R ⁵⁰ and R ^D is preferably a linear or branched aliphatic hydrocarbon group or an alicyclic hydrocarbon group.

  Examples of the sulfonium salt compound represented by the above formula (EE-2) include compounds represented by the following formula.

  As the photodegradable base, a sulfonium salt compound represented by the above formula (EE-2) is preferable.

  When the said radiation sensitive resin composition contains an [E] acid diffusion control agent, as content of an [E] acid diffusion control agent, it is 10 mass parts or less normally with respect to 100 mass parts of [B] polymers. It is. [E] When the content of the acid diffusion controller exceeds 10 parts by mass, the sensitivity as a resist tends to decrease.

  The radiation-sensitive resin composition (Z) includes, for example, [A] polymer, [B] polymer, [C] radiation-sensitive acid generator, and [E] acid diffusion control agent, if necessary, [D]. It can be prepared by dissolving in a solvent and preferably filtering the resulting mixture with a filter having a pore size of about 0.2 μm. The lower limit of the total solid content concentration of the radiation-sensitive resin composition (Z) is preferably 0.2% by mass, more preferably 0.5% by mass, and even more preferably 1% by mass from the viewpoint of ease of application. The upper limit of the total solid content concentration is preferably 50% by mass, more preferably 30% by mass, and still more preferably 10% by mass.

  Examples of the coating method of the radiation sensitive resin composition (Z) include conventionally known coating methods such as spin coating, cast coating, roll coating, and the like. After applying on the substrate, pre-baking (PB) may be performed to volatilize the solvent. As a minimum of the temperature of PB, 50 degreeC is preferable and 80 degreeC is more preferable. As an upper limit of the said temperature, 150 degreeC is preferable and 120 degreeC is more preferable. The lower limit of the PB time is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. As a minimum of average thickness of the resist film formed, 10 nm is preferred, 20 nm is more preferred, and 50 nm is still more preferred. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm, and even more preferably 200 nm.

[Upper layer formation process]
In this step, an upper layer film is formed on one surface of the resist film with the upper layer film forming composition (S). Examples of the method for applying the upper layer film forming composition (S) include the same method as the method for applying the radiation sensitive resin composition (Z) in the resist film forming step. In this step, it is preferable to perform pre-baking (PB) after applying the upper layer film-forming composition (S). As a minimum of the temperature of PB, 50 degreeC is preferable and 80 degreeC is more preferable. As an upper limit of the said temperature, 150 degreeC is preferable and 120 degreeC is more preferable. The lower limit of the PB time is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. As a minimum of the film thickness of the upper layer film formed, 10 nm is preferred, 20 nm is more preferred, and 50 nm is still more preferred. The upper limit of the film thickness is preferably 300 nm, more preferably 200 nm, and even more preferably 150 nm. Further, the thickness of the upper layer film to be formed is preferably as close as possible to λ / 4m (λ: wavelength of radiation, m: refractive index of the upper layer film). By doing in this way, the reflection suppression effect in the upper interface of a resist film can be enlarged.

  By forming the upper layer film on one side of the resist film, the immersion liquid and the resist film are not in direct contact with each other, so that the lithography performance of the resist film is reduced due to the immersion liquid penetrating the resist film. And contamination of the lens of the projection exposure apparatus by components eluted from the resist film into the immersion liquid is effectively suppressed.

[Immersion exposure process]
In this step, the resist film on which the upper layer film is formed is subjected to immersion exposure. This immersion exposure is performed by placing an immersion liquid on the upper layer film and exposing through the immersion liquid.

  As the immersion liquid, a liquid having a refractive index higher than that of air is usually used. As the immersion liquid, water is preferably used, and pure water is more preferably used. Note that the pH of the immersion liquid may be adjusted as necessary. In a state where the immersion liquid is interposed, that is, in a state where the immersion liquid is filled between the lens and the upper layer film of the exposure apparatus, exposure light is irradiated from the exposure apparatus and is passed through a mask having a predetermined pattern. To expose the resist film.

  The exposure light used for this immersion exposure can be appropriately selected according to the type of the resist film and the upper layer film. For example, visible light; ultraviolet light such as g-line and i-line; far ultraviolet light such as excimer laser light; Electromagnetic waves such as X-rays such as radiation; particle beams such as charged particle beams such as electron beams. Among these, far ultraviolet rays are preferable, ArF excimer laser light (wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm) are more preferable, and ArF excimer laser light is more preferable. Moreover, the irradiation conditions of exposure light, for example, the exposure amount, etc. are appropriately determined according to the composition of the radiation-sensitive resin composition (Z) and the composition for forming an upper layer film (S), the type of additives contained therein, and the like. Can be set.

  After the immersion exposure, post-exposure baking (PEB) is preferably performed in order to improve the resolution, pattern shape, developability, and the like of the resulting resist pattern. The temperature of PEB can be appropriately set depending on the type of the radiation-sensitive resin composition (Z) and the upper layer film-forming composition used. As a minimum of the temperature of PEB, 30 ° C is preferred and 50 ° C is more preferred. As an upper limit of the said temperature, 200 degreeC is preferable and 150 degreeC is more preferable. The lower limit of the PEB time is preferably 5 seconds, and more preferably 10 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds.

[Development process]
In this step, the immersion-exposed resist film is developed with a developer containing an organic solvent. Thereby, a desired negative resist pattern can be obtained.

  Examples of the organic solvent contained in the developer include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like. As the organic solvent for the developer, those containing an ester solvent, a ketone solvent or a combination thereof are preferable. The said developing solution may contain the organic solvent individually by 1 type, and may contain 2 or more types.

Examples of the alcohol solvent include aliphatic monoalcohol solvents having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcohol solvent having 3 to 18 carbon atoms such as cyclohexanol;
A C2-C18 polyhydric alcohol solvent such as 1,2-propylene glycol;
Examples thereof include C3-C19 polyhydric alcohol partial ether solvents such as propylene glycol monomethyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
2,4-pentanedione, acetonylacetone, acetophenone and the like can be mentioned.

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

Examples of ester solvents include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvents such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate;
Polycarboxylic acid diester solvents such as diethyl oxalate;
Examples thereof include carbonate solvents such as dimethyl carbonate and diethyl carbonate.

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

  Among these, ester solvents, ketone solvents, ether solvents and combinations thereof are preferable, and ester solvents, ketone solvents and combinations thereof are more preferable. As the ester solvent, n-butyl acetate, isopropyl acetate and amyl acetate are preferable. As the ketone solvent, 2-butanone, methyl-n-butyl ketone and methyl-n-amyl ketone are preferable. As the ether solvent, anisole is preferable.

  As a minimum of content of the organic solvent in a developing solution, 80 mass% is preferred, 90 mass% is more preferred, 99 mass% is still more preferred, and 100 mass% is especially preferred. By making the content of the organic solvent in the developer within the above range, the dissolution contrast between the exposed part and the unexposed part can be improved, and as a result, a resist pattern having better lithography performance can be formed. Can do. Examples of components other than the organic solvent include water and silicone oil.

  The developer may contain a nitrogen-containing compound. When the developer contains a nitrogen-containing compound, film loss in the formed resist pattern can be further reduced.

  As a nitrogen-containing compound, the compound etc. which were illustrated as a [K] acid spreading | diffusion suppression compound of the composition (S) for upper layer film formation mentioned later, for example are mentioned.

  An appropriate amount of a surfactant can be added to the developer as necessary. Examples of the surfactant include ionic and nonionic fluorine-based surfactants and silicon-based surfactants.

  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.

  In the development step, the resist film is preferably washed with a rinsing liquid after the development. An organic solvent can be used as the rinse liquid. By using an organic solvent as the rinsing liquid, the generated scum can be efficiently washed.

  Examples of the organic solvent used as the rinse liquid include hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and the like. Of these, alcohol solvents and ester solvents are preferred, and alcohol solvents are more preferred. As the alcohol solvent, a monovalent alcohol solvent having 6 to 8 carbon atoms is preferable.

  Examples of the monovalent alcohol solvent having 6 to 8 carbon atoms include linear, branched or cyclic monohydric alcohols, and specifically, 1-hexanol, 1-heptanol, 1-octanol. 4-methyl-2-pentanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol and the like. Of these, 1-hexanol, 2-hexanol, 2-heptanol and 4-methyl-2-pentanol are preferred.

  The organic solvent contained in a rinse liquid may be used individually by 1 type, and may use 2 or more types together. The upper limit of the moisture content in the rinse liquid is preferably 10% by mass, more preferably 5% by mass, and still more preferably 3% by mass. By setting the water content in the rinsing liquid to the upper limit or less, good development characteristics can be obtained. A surfactant can be added to the rinse liquid.

  As a cleaning treatment method using a rinsing liquid, for example, a method of continuously applying the rinsing liquid onto a substrate rotating at a constant speed (rotary coating method), or a method of immersing the substrate in a tank filled with the rinsing liquid for a certain period of time (Dip method), a method (spray method) of spraying a rinsing liquid on the substrate surface, and the like.

[Upper layer removal process]
In this step, after the immersion exposure step, the upper layer film formed in the upper layer film formation step is removed simultaneously with or before the development step.

  The method for removing the upper layer film is not particularly limited, but is preferably a method that does not impair the lithography performance of the resist pattern. According to the negative resist pattern forming method, since the upper layer film is formed using the upper layer film forming composition (S), the upper layer film can be easily formed with a developer and / or a rinsing liquid in the development step. Can be removed. That is, the upper layer film can be removed in the development step, and a step for removing the upper layer film is not required separately from the development step.

<Upper layer film forming composition (S)>
The composition for forming an upper layer (S) contains a [J] polymer and a [P] solvent, and the composition for forming an upper layer (S) is selected from the group consisting of (i) and (ii) below. Satisfy at least one selected.
(I) The composition for forming an upper layer film further contains a [K] acid diffusion inhibiting compound. (Ii) The [J] polymer contains a structural unit (VI) having an acid diffusion inhibiting group.

  The [K] acid diffusion inhibiting compound includes a compound represented by the following formula (1), a compound represented by the following formula (2), a compound represented by the following formula (3), or a combination thereof.

In the above formula (1), R ^A and R ^B are a hydrogen atom, a monovalent organic group having 1 to 20 carbon atoms, or are configured together with a nitrogen atom to which these groups are combined and bonded to each other. An aliphatic heterocyclic structure having 3 to 20 ring members is represented. R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms.

In the above formula (2), X ⁺ is a monovalent onium cation. Y ⁻ is a monovalent weak acid anion.

In the above formula (3), R ¹⁸ , R ¹⁹ and R ²⁰ are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, an aryl group or an aralkyl group. .

  The acid diffusion inhibiting group is a group represented by the following formula (1 ′), a group represented by the following formula (2′-1), a group represented by the following formula (2′-2), the following formula ( 3 '), or a combination thereof.

In said formula (1 '), E is a single bond or a C1-C20 bivalent organic group. R ^J is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. RJ and E may represent an aliphatic heterocyclic structure having 3 to 20 ring members that is configured together with the nitrogen atom to which they are bonded. R ¹ ′ is a monovalent hydrocarbon group having 1 to 20 carbon atoms.

In the above formula (2′-1), X ′ ⁺ is a monovalent group containing a monovalent onium cation. Y ^'- is a monovalent weak acid anions.

In the above formula (2′-2), Y ″ ^— is a monovalent group containing a monovalent weak acid anion. X ″ ⁺ is a monovalent onium cation.

In the above formula (3 ′), E ′ is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ²⁸ and R ²⁹ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ²⁸ , R ^29, and E ′ may represent an aliphatic heterocyclic structure having 3 to 20 ring members that is formed together with the nitrogen atom to which any two of these groups are combined with each other.

  The composition for forming an upper layer film (S) is used in a negative resist pattern forming method using a developer containing an organic solvent. According to the negative resist pattern forming method using a developer containing an organic solvent, the optical contrast can be increased compared to the positive resist pattern forming method using a developer such as an alkaline aqueous solution. A resist pattern can be formed. Further, “(i) the composition for forming an upper layer film further contains a [K] acid diffusion inhibiting compound” and “(ii) the structural unit (VI) in which the [J] polymer has an acid diffusion inhibiting group”. By satisfying at least one selected from the group consisting of “comprising”, acid diffusion to the unexposed area and deprotection reaction can be suppressed, and high dissolution contrast can be imparted. In particular, the desired line width can be resolved even under low optical contrast conditions such as defocusing, and the process window can be improved. Hereinafter, each component will be described.

<[J] polymer>
[J] The polymer has a structural unit (IV). The [J] polymer has a structural unit (V) containing a fluorine atom (excluding the structural unit (IV) described later), a structural unit (VI) having an acid diffusion inhibiting group, or a combination thereof. preferable. Hereinafter, each structural unit will be described.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing a hydrocarbon structure.

  Examples of the hydrocarbon structure include hydrocarbon structures such as a chain hydrocarbon structure, an alicyclic hydrocarbon structure, and an aromatic hydrocarbon structure. Here, the chain hydrocarbon structure, alicyclic hydrocarbon structure and aromatic hydrocarbon structure refer to structures derived from chain hydrocarbon, alicyclic hydrocarbon and aromatic hydrocarbon, respectively.

Examples of the chain hydrocarbon structure include alkyl structures such as an n-propyl structure, an i-propyl structure, an n-butyl structure, an i-butyl structure, a sec-butyl structure, and a t-butyl structure;
Alkenyl structures such as propenyl structure and butenyl structure;
Examples thereof include alkynyl structures such as propynyl structure and butynyl structure.
The alkyl structure, alkenyl structure, and alkynyl structure preferably have 2 to 20 carbon atoms.

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

Examples of the alicyclic structure include monocyclic alicyclic saturated hydrocarbon structures such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cyclooctane structure, a cyclodecane structure, and a cyclododecane structure;
A monocyclic structure such as a monocyclic alicyclic unsaturated hydrocarbon structure such as cyclopropene structure, cyclobutene structure, cyclopentene structure, cyclohexene structure, cyclooctene structure, cyclodecene structure, cyclododecene structure,
Polycyclic alicyclic saturated hydrocarbon structures such as norbornane structure, adamantane structure, tricyclodecane structure, tetracyclododecane structure;
Examples thereof include polycyclic structures such as a polycyclic alicyclic unsaturated hydrocarbon structure such as a norbornene structure, a tricyclodecene structure, and a tetracyclododecene structure.

  As the structural unit (IV), an alicyclic structure is preferable because the receding contact angle between the upper layer film and the immersion liquid is increased, and high-speed scanning exposure is possible without leaving water droplets. The structure is more preferable, and a polycyclic alicyclic saturated hydrocarbon structure is more preferable.

  Examples of the structural unit (IV) include a structural unit derived from a (meth) acrylic acid ester having an alicyclic structure (hereinafter, also referred to as “structural unit (IV-1)”), and exo-methylene lactone having an alicyclic structure. And a structural unit derived from cycloolefin (hereinafter also referred to as “structural unit (IV-3)”) and the like. Examples of the structural unit (IV-1) include a structural unit represented by the following formula (6-1) (hereinafter also referred to as “structural unit (IV-1a)”). Examples of the structural unit (IV-2) include a structural unit represented by the following formula (6-2) (hereinafter also referred to as “structural unit (IV-2a)”). Examples of the cycloolefin include substituted or unsubstituted norbornene, substituted or unsubstituted tricyclodecene, substituted or unsubstituted tetracyclododecene, and the like.

In the formula ^{(6-1), R 21} is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ²² is a substituted or unsubstituted monovalent alicyclic hydrocarbon group having 3 to 20 ring members.
In said formula (6-2), R < ^{21 '>} is a hydrogen atom or a methyl group. Y ¹ , Y ² and Y ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. a is an integer of 1 to 4. When a is 2 or more, the plurality of Y ¹ may be the same or different, and the plurality of Y ² may be the same or different. L ′ is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ^{22 ′} is a substituted or unsubstituted monovalent alicyclic hydrocarbon group having 3 to 20 ring members.

R ²¹ 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 (IV-1). R ^{21 ′} is preferably a hydrogen atom from the viewpoint of the copolymerizability of the monomer giving the structural unit (IV-2).

  Examples of the divalent organic group having 1 to 20 carbon atoms represented by L and L ′ include, for example, a divalent hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon boundary of this hydrocarbon group or a bond side. Examples include a group (α) containing a divalent heteroatom-containing group at the terminal, a group obtained by substituting part or all of the hydrogen atoms of the hydrocarbon group and the group (α) with a monovalent heteroatom-containing group. It is done.

  L and L ′ are preferably a single bond and a chain hydrocarbon group having 1 to 5 carbon atoms, more preferably a single bond and a methanediyl group, and even more preferably a single bond.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 ring members represented by R ²² and R ^{22 ′} include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a cyclodecyl group, a cyclo Monocyclic alicyclic saturated hydrocarbon groups such as dodecyl groups;
A monocyclic alicyclic hydrocarbon group such as a monocyclic alicyclic unsaturated hydrocarbon group such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group, a cyclooctenyl group, a cyclodecenyl group, and a cyclododecenyl group,
A polycyclic alicyclic saturated hydrocarbon group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
And polycyclic alicyclic hydrocarbon groups such as polycyclic alicyclic unsaturated hydrocarbon groups such as norbornenyl group, tricyclodecenyl group and tetracyclododecyl group.

  Examples of the substituent for the alicyclic hydrocarbon group include a hydrocarbon group having 1 to 10 carbon atoms, a hydroxy group, a cyano group, a nitro group, and a sulfanyl group.

R ²² and R ^{22 ′} are preferably an unsubstituted alicyclic hydrocarbon group, more preferably a polycyclic alicyclic hydrocarbon group, still more preferably a polycyclic alicyclic saturated hydrocarbon group, An alicyclic saturated hydrocarbon group having a ring is more preferable, a tricyclodecanyl group is particularly preferable, and a tricyclo [5.2.1.0 ^2,6 ] decanyl group is further particularly preferable.

  As the structural unit (IV-1), for example, structural units represented by the following formulas (6-1-1) to (6-1-9) (hereinafter referred to as “structural units (IV-1a-1) to (IV)”) -1a-9) ") and the like. Examples of the structural unit (IV-2) include structural units represented by the following formulas (6-2-1) and (6-2-2) (hereinafter referred to as “structural units (IV-2a-1), (IV -2a-2) "etc. Examples of the structural unit (IV-3) include structural units represented by the following formulas (6-3-1) and (6-3-2) (hereinafter referred to as" structure "). Units (IV-3-1) and (IV-3-2) ”).

In the formulas (6-1-1) to (6-1-9), R ²¹ has the same meaning as the formula (6-1).
As the structural unit (IV), structural units (IV-1) and (IV-2) are preferable, and the structural units (IV-1a-1) to (IV-1a-9), (IV-2a-1) and (IV-2a-2) is more preferable, and structural units (IV-1a-1), (IV-1a-9), and (IV-2a-1) are more preferable.

  [J] The lower limit of the content ratio of the structural unit (IV) in the polymer is preferably 50 mol%, more preferably 65 mol%, and more preferably 70 mol% with respect to all the structural units constituting the [J] polymer. Is more preferable, 75 mol% is particularly preferable, and 80 mol% is most preferable.

  By making the content rate of structural unit (IV) into the said range, the solubility to the developing solution of a [J] polymer can be adjusted more appropriately, As a result, according to the said resist pattern formation method, Both the water repellency on the surface of the upper layer film and the suppression of development defects can be enhanced.

[Structural unit (V)]
The structural unit (V) is a structural unit containing a fluorine atom other than the structural unit (IV). That is, the structural unit having an alicyclic structure and containing a fluorine atom is included in the structural unit (IV).

[J] When the polymer has the structural unit (V), the [J] polymer has the structural unit (IV) and the structural unit (V) in the same or different polymers. [J] Examples of the case where the polymer has the structural unit (V) include the following [J1] polymer and [J2] polymer.
[J1] Polymer: A polymer (a) having a structural unit (IV) and a polymer (b) having a structural unit (V) are included.
[J2] Polymer: Includes “polymer (c)” having structural unit (IV) and structural unit (V).

  [J1] The polymer may contain a polymer other than the polymer (a) and the polymer (b). [J2] The polymer may contain a polymer other than the polymer (c).

  Examples of the structural unit (V) include a structural unit (V-1) containing a group represented by the following formula (7), a structural unit (V-2) containing a fluorinated alkyl group, and the like.

(Structural unit (V-1))
The structural unit (V-1) is a structural unit including a group represented by the following formula (7) (hereinafter also referred to as “group (7)”). [J] By having the structural unit (V-1), the polymer can adjust water repellency and solubility in a developer more appropriately. As a result, the water repellency and defect suppression of the upper layer film surface can be further improved.

In the above formula (7), R 2 ^O is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ^P and R ^Q are each independently a fluorine atom or a fluorinated alkyl group having 1 to 20 carbon atoms.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R 2 ^O include, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon boundary of this hydrocarbon group, or a terminal on the bond side. Examples include groups containing heteroatom-containing groups, groups in which part or all of the hydrogen atoms of these groups have been substituted with substituents.

As R 2 ^O , a hydrogen atom is preferable from the viewpoint of adjusting the solubility in the developer to a more appropriate level and further improving the suppression of development defects.

The fluorinated alkyl group having 1 to 20 carbon atoms represented by R ^P and R ^Q, for example, fluoromethyl group, difluoromethyl group, difluoroethyl group, trifluoroethyl group, trifluoropropyl group, pentafluoropropyl group, A partially fluoro-substituted alkyl group such as a heptafluorobutyl group and a nonafluoropentyl group;
Examples thereof include perfluoroalkyl groups such as a trifluoromethyl group, a pentafluoroethyl group, a hexafluoropropyl group, a nonafluorobutyl group, and an undecafluoropentyl group. Among these, a perfluoroalkyl group is preferable and a trifluoromethyl group is more preferable.

  Examples of the group (7) include groups represented by the following formulas (7-1) to (7-8) (hereinafter also referred to as “groups (7-1) to (7-8)”). .

  As the group (7), a hydroxybis (perfluoroalkyl) methyl group is preferable, groups (7-1) to (7-3) are more preferable, and a group represented by the group (7-1) is more preferable.

  Examples of the structural unit (V-1) include a structural unit represented by the following formula (7-a) (hereinafter, also referred to as “structural unit (V-1a)”), and a structural unit (V-a). Structural units (hereinafter also referred to as “structural units (V-1b)”) and the like.

In said formula (7-a), ^RD is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^E is a divalent linking group. R ^X is the group (7).
In the formula (7-b), R ^Y is the group (7). R ^F is a single bond or a divalent linking group. R ^G is a hydrogen atom or a monovalent organic group.

^RD 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 (V-1a).

Examples of the divalent linking group represented by R ^E, for example, a divalent chain hydrocarbon group having 1 to 6 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, said chain hydrocarbon Examples thereof include a group containing -O-, -D-, -CO-, -CD- or a combination of these between carbon-carbon of a hydrogen group and an alicyclic hydrocarbon group.

Examples of the divalent chain hydrocarbon group having 1 to 6 carbon atoms include a methanediyl group, a 1,1-ethanediyl group, a 1,2-ethanediyl group, a 1,1-propanediyl group, and a 1,2-propanediyl group. 1,3-propanediyl group, 2,2-propanediyl group, 1,4-propanediyl group, 1,5-pentanediyl group, 1,6-hexanediyl group, 1-methyl-1,3-propanediyl Group, 2-methyl-1,3-propanediyl group, 2-methyl-1,2-propanediyl group, 1-methyl-1,4-butanediyl group, 2-methyl-1,4-butanediyl group, etc. Diyl group;
Alkenediyl groups such as 1,2-ethenediyl group, 1,3-propenediyl group, 1,2-propenediyl group;
Examples include alkynediyl groups such as 1,2-ethynediyl group and 1,3-propynediyl group.
Of these, alkanediyl groups are preferred, methanediyl groups, ethanediyl groups and propanediyl groups are more preferred, methanediyl groups, 1,1-ethanediyl groups, 1,2-ethanediyl groups, 1,2-propanediyl groups and 1 1,3-propanediyl group is more preferable, and 1,2-propanediyl group is particularly preferable.

Examples of the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms include cyclobutanediyl groups such as 1,3-cyclobutanediyl groups, cyclopentanediyl groups such as 1,3-cyclopentanediyl groups, 1,4 -Cyclohexanediyl group such as cyclohexanediyl group, 1,2-cyclohexanediyl group, cyclooctanediyl group such as 1,5-cyclooctanediyl group, 1,1-cyclopentylethanediyl group, 1,2-cyclopentylethanediyl group A monocyclic cycloalkanediyl group such as a cyclohexylethanediyl group such as a cyclopentylethanediyl group such as 1,1-cyclohexylethanediyl group, 1,2-cyclohexylethanediyl group;
1,4-norbornanediyl group, norbornanediyl group such as 2,5-norbornanediyl group, 1,3-adamantanediyl group, adamantanediyl group such as 2,4-adamantanediyl group, 2,7-tetracyclododecanediyl And a polycyclocycloalkanediyl group such as a tetracyclododecanediyl group, a norbornylmethanediyl group, an adamantylmethanediyl group, and the like.
Among these, norbornanediyl group, tetracyclododecanediyl group and cyclohexylethanediyl group are preferable, and 2,5-norbornanediyl group, 2,7-tetracyclododecanediyl group and 1,2-cyclohexylethanediyl group are more preferable. A 1,2-cyclohexylethanediyl group is more preferable.

  Examples of the structural unit (V-1a) include structural units represented by the following formulas (7-a-1) to (7-a-5) (hereinafter referred to as “structural units (V-1a-1) to (V -1a-5) ") and the like.

In the above formulas (7-a-1) to (7-a-5), R ^A has the same meaning as the above formula (7). ^RD is synonymous with the above formula (7-a).

Examples of the divalent linking group represented by R ^F include a divalent chain hydrocarbon group having 1 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and the above chain carbon group. Examples include a group in which one or more of a hydrogen group and an alicyclic hydrocarbon group are combined with -O-.

  Examples of the divalent chain hydrocarbon group having 1 to 20 carbon atoms include methanediyl group, ethanediyl group, propanediyl group, butanediyl group, pentanediyl group, hexanediyl group, octanediyl group, decandidiyl group, dodecanediyl group, and tetradecandiyl group. Group, hexadecandiyl group, octadecandiyl group, icosanediyl group and the like.

  Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, a cyclohexanediyl group, a cyclooctanediyl group, and a cyclodecandidiyl group.

  Examples of the group in which one or more of a chain hydrocarbon group and an alicyclic hydrocarbon group are combined with -O- include, for example, a methanediyloxy group, an ethanediyloxy group, a propanediyloxy group, and butane. Alkanediyloxy groups such as diyloxy group, pentanediyloxy group, hexanediyloxy group, octanediyloxy group; methanediyloxymethanediyl group, methanediyloxyethanediyl group, methanediyloxy (6,2-propanediyl) A group containing one —O— such as a group, a methanediyloxybutanediyl group, a methanediyloxycyclohexanediyl group; a group containing two or more —O— such as a propanediyloxyethanediyloxyethanediyl group, etc. Can be mentioned.

Among these, R ^F is preferably a single bond, a methanediyl group, an alkanediyloxy group having 2 to 4 carbon atoms, or a cycloalkanediyloxy group having 7 to 10 carbon atoms. -Ethanediyloxy group, 1,2-propanediyloxy group and 2,6-norbornanediyloxy group are more preferable, and 1,2-ethanediyloxy group is more preferable.

Examples of the monovalent organic group represented by ^RG include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and 6 to 6 carbon atoms. 20 monovalent aromatic hydrocarbon groups or one or more of them and a linking group containing a heteroatom such as -O-, -CO-, -OCO-, -COO-, -D- And a combination of these and the like. Some or all of the hydrogen atoms of these groups may be substituted with a fluorine atom, a hydroxy group, a carboxy group, an amino group, a cyano group, or the like.

R ^G includes a hydrogen atom, a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, a monovalent fluorinated chain hydrocarbon group, a monovalent fluorinated alicyclic hydrocarbon group, A monovalent hydroxy chain hydrocarbon group, a group containing a hydroxybis (perfluoroalkyl) methyl group and a group having a monovalent lactone structure are preferred, and a hydrogen atom, a methyl group, an ethyl group, an i-propyl group, an n- Butyl group, cyclohexylmethyl group, hexafluoro-2-propyl group, 2-hydroxyethyl group, hydroxybis (perfluoroalkyl) butyl group, hydroxybis (perfluoroalkyl) methylnorbornyl group, α-butyrolactone-yl group Norbornanelactone-yl group and trifluoromethylnorbornanelactone-yl group are more preferable, and methyl group and ethyl group are more preferable. .

  Examples of the structural unit (V-1b) include structural units represented by the following formulas (7-b-1) to (7-b-13) (hereinafter referred to as “structural units (V-1b-1) to (V -1b-13) ") and the like.

In the above formulas (7-b-1) to (7-b-13), R ^A has the same meaning as the above formula (7).

  Among these, the structural units (V-1b-1) to (V-1b-9), the structural unit (V-1b-13), and the structural unit (V-1b-16) are preferable, and the structural unit (V— 1b-1) and structural units (V-1b-2) are more preferred.

  [J] The lower limit of the content ratio of the structural unit (V-1) in the polymer is preferably 10 mol%, more preferably 20 mol%, based on all structural units constituting the [J] polymer, 35 More preferred is mol%, particularly preferred is 45 mol%. As an upper limit of the said content rate, 90 mol% is preferable, 80 mol% is more preferable, 75 mol% is further more preferable, 60 mol% is especially preferable.

  [J] When the polymer is a [J1] polymer, the lower limit of the content ratio of the structural unit (V-1) is preferably 10 mol% with respect to all the structural units constituting the polymer (b). , 20 mol% is more preferable, 30 mol% is more preferable, and 40 mol% is particularly preferable. As an upper limit of the said content rate, 100 mol% is preferable, 90 mol% is more preferable, 80 mol% is further more preferable, 75 mol% is especially preferable.

  When the [J] polymer is the [J2] polymer, the lower limit of the content ratio of the structural unit (V-1) is 0.5 mol% with respect to all the structural units constituting the polymer (c). Is preferable, 1 mol% is more preferable, 1.5 mol% is further more preferable, and 2 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 35 mol% is further more preferable, 30 mol% is especially preferable.

  By making the content rate of a structural unit (V-1) into the said range, both the water repellency and defect inhibitory property of an upper film surface can be improved further.

(Structural unit (V-2))
The structural unit (V-2) is a structural unit containing a fluorinated alkyl group. [J] The polymer can further improve the water repellency of the upper layer film by having the structural unit (V-2).

  Examples of the fluorinated alkyl group include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, a pentafluoroethyl group, a fluoro-n-propyl group, and a difluoro-n-. Propyl group, trifluoro-n-propyl group, pentafluoro-n-propyl group, heptafluoro-n-propyl group, fluoro-i-propyl group, trifluoro-i-propyl group, hexafluoro-i-propyl group, Examples include a fluoro-n-butyl group, an octafluoro-n-butyl group, a nonafluoro-n-butyl group, an undecafluoro-n-pentyl group, and a heptadecafluoro-n-decyl group.

  As the structural unit (V-2), from the viewpoint of copolymerization of the monomer that gives the structural unit (V-2), a structural unit represented by the following formula (8) (hereinafter referred to as “structural unit (V— 2a) ") is preferred.

In said formula (8), ^RH is a hydrogen atom, a methyl group, a fluorine atom, or a trifluoromethyl group. R ^I is a monovalent fluorinated alkyl group.

The ^RH is preferably a hydrogen atom and a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (IV-2a).

Examples of the monovalent fluorinated alkyl group represented by R ^I include the groups exemplified as the above-described fluorinated alkyl group.

  Examples of the structural unit (V-2a) include structural units represented by the following formulas (8-1) to (8-6) (hereinafter referred to as “structural units (V-2a-1) to (V-2a-6)”. ) ")) And the like.

In the above formulas (8-1) to (8-6), ^RH is synonymous with the above formula (8).

  [J] The lower limit of the content ratio of the structural unit (V-2) in the polymer is preferably 10 mol%, more preferably 20 mol%, based on all the structural units constituting the [J] polymer, 30 More preferred is mol%. As an upper limit of the said content rate, 80 mol is preferable, 70 mol% is more preferable, and 60 mol% is further more preferable.

  [J] When the polymer is a [J1] polymer, the lower limit of the content ratio of the structural unit (V-2) is preferably 10 mol% with respect to all the structural units constituting the polymer (b). , 20 mol% is more preferable, 30 mol% is more preferable, and 40 mol% is particularly preferable. As an upper limit of the said content rate, 100 mol% is preferable, 90 mol% is more preferable, 80 mol% is further more preferable, 75 mol% is especially preferable.

  [J] When the polymer is a [J2] polymer, the lower limit of the content ratio of the structural unit (V-2) is 0.5 mol% with respect to all the structural units constituting the polymer (c). Is preferable, 1 mol% is more preferable, 1.5 mol% is further more preferable, and 2 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 35 mol% is further more preferable, 30 mol% is especially preferable.

  By making the content rate of a structural unit (V-2) into the said range, the water repellency of the surface of an upper layer film can further be improved.

[Structural unit (VI)]
The structural unit (VI) is a structural unit having an acid diffusion inhibiting group. [J] When the polymer component has the structural unit (VI), excessive diffusion of the acid to the unexposed portion is suppressed by the action of the acid diffusion suppressing group, and the lithography characteristics can be improved.

  Examples of the acid diffusion inhibiting group include basic groups such as an amino group, a monohydrocarbon group-substituted amino group, a dihydrocarbon group-substituted amino group, a cyclic amino group, and an amide group.

Examples of the monohydrocarbon group-substituted amino group include monoalkylamino groups such as a methylamino group, an ethylamino group, and a propylamino group;
A monocycloalkylamino group such as a cyclopentylamino group and a cyclohexylamino group;
Monoarylamino groups such as a phenylamino group and a naphthylamino group;
Examples thereof include monoaralkylamino groups such as benzylamino group and phenethylamino group.

Examples of the dihydrocarbon group-substituted amino group include dialkylamino groups such as dimethylamino group, methylethylamino group, diethylamino group and dipropylamino group;
A dicycloalkylamino group such as a dicyclopentylamino group, a dicyclohexylamino group, a dinorbornylamino group;
Diarylamino groups such as diphenylamino group, ditolylamino group, dinaphthylamino group, phenyltolylamino group;
Examples thereof include diaralkylamino groups such as dibenzylamino group, diphenethylamino group, and di (naphthylmethyl) amino group.

  Examples of the cyclic amino group include an azacyclopentyl group (pyrrolidinyl group), an azacyclohexyl group (piperidinyl group), an azacyclooctyl group, and the like.

  Examples of the amide group include a dimethylamide group and a diethylamide group.

  As the acid diffusion inhibiting group, a group having an acid dissociable group can also be used. Examples of the acid diffusion inhibiting group having such an acid dissociable group include N- (t-butoxycarbonyl) piperidinyl group, N- (t-butoxycarbonyl) imidazole group, N- (t-amyloxycarbonyl) methylethyl. An amino group etc. are mentioned.

  Among these, as the acid diffusion inhibiting group, a dihydrocarbon group-substituted amino group is preferable, a dialkylamino group is more preferable, and a dimethylamino group is further preferable.

  Examples of the structural unit (VI) include a structural unit represented by the following formula (9) (hereinafter also referred to as “structural unit (VI-a)”).

In said formula (9), ^RU is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. W is —COO— or —NH—. R ^V is a group containing an acid diffusion inhibiting group.

The R ^U, from the viewpoint of copolymerizability of the monomer giving the structural units (VIII), preferably a hydrogen atom or a methyl group, more preferably a methyl group.

Examples of the group containing an acid diffusion-inhibiting group represented by R ^V, for example, such monovalent hydrocarbon radicals acid diffusion inhibiting group described above is bonded and the like. Among these, a dihydrocarbon group-substituted amino hydrocarbon group and an Nt-alkoxycarbonyl-substituted cyclic amino group are preferable, a dialkylaminoalkyl group and an Nt-alkoxycarbonylazacycloalkyl group are more preferable, and dimethylaminoethyl And more preferred are Nt-butoxycarbonyl azacyclohexyl group.

  Examples of the acid diffusion inhibiting group include groups represented by the following formula (1 '), the following formula (2'-1), the following formula (2'-2), and the following formula (3').

In said formula (1 '), E is a single bond or a C1-C20 bivalent organic group. R ^J is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ^J and E may represent an aliphatic heterocyclic structure having 3 to 20 ring members that is formed together with the nitrogen atom to which they are bonded. R ¹ ′ is a monovalent hydrocarbon group having 1 to 20 carbon atoms.

  Examples of the divalent organic group having 1 to 20 carbon atoms represented by E above include, for example, a divalent hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon boundary of this hydrocarbon group, or a terminal on the bond side. Examples include a group (α) containing a divalent heteroatom-containing group, a group obtained by substituting part or all of the hydrogen atoms of the hydrocarbon group and the group (α) with a monovalent heteroatom-containing group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^J above include, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon boundary of this hydrocarbon group, or a terminal on the bond side. And a group containing a heteroatom-containing group, a group in which part or all of the hydrogen atoms of these groups are substituted with a substituent, and the like.

Examples of the aliphatic heterocyclic structure having 3 to 20 ring members composed of the above R ^J and E groups together with the nitrogen atom to which they are bonded include:
Azacycloalkane structures such as an azacyclopropane structure, an azacyclobutane structure, an azacyclopentane structure, an azacyclohexane structure, an azacyclooctane structure, an azacyclodecane structure, an azanorbornane structure, an azaadamantane structure;
An azaoxacycloalkane structure such as an azaoxacyclopentane structure, an azaoxacyclohexane structure, an azaoxacyclooctane structure, an azaoxanorbornane structure;
Examples thereof include diazacyclopentane structures, diazacyclohexane structures, diazacyclooctane structures, diazacyclodecane structures, and diazacycloalkane structures such as diazanorbornane structures.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹ ′ include a linear or branched chain hydrocarbon group having 1 to 20 carbon atoms and 3 to 20 carbon atoms. And an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and the like.

  Examples of the chain hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group; an alkenyl group such as an ethenyl group, a propenyl group, a butenyl group and a pentenyl group; an ethynyl group and a propynyl group Alkynyl groups such as butynyl group and pentynyl group.

  Examples of the alicyclic hydrocarbon group include monocyclic alicyclic saturated hydrocarbon groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclohexyl group; norbornyl group, adamantyl group, tricyclodecyl group, tetracyclododecyl Polycyclic alicyclic saturated hydrocarbon group such as a group; monocyclic alicyclic unsaturated hydrocarbon group such as cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group; norbornenyl group, tricyclodecenyl And polycyclic alicyclic unsaturated hydrocarbon groups.

  Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group and anthryl group; aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group and anthrylmethyl group. It is done.

In the above formula (2′-1), X ′ ⁺ is a monovalent group containing a monovalent onium cation. Y ^'- is a monovalent weak acid anions.

Examples of the monovalent onium cation contained in the monovalent group represented by X ′ ⁺ include a sulfonium cation, an iodonium cation, an ammonium cation, and an oxonium cation.

The Y ^'- as the monovalent weak acid anion represented by include the example monovalent carboxylate anion or monovalent sulfonamide anion.

The Y ^'- as the monovalent carboxylate anion represented by include salicylate anion. Examples of the monovalent sulfonamide anion represented by Y- include trifluoromethylsulfonamide ion.

The Y ^'- 1 monovalent weak acid anion represented by is preferably a weaker acid than the acid generated from the [C] photoacid generator.

In the above formula (2′-2), Y ″ ^— is a monovalent group containing a monovalent weak acid anion. X ″ ⁺ is a monovalent onium cation.

^'- As the monovalent weak acid anion contained in the monovalent group represented by, for example the Y' ^- the Y 'exemplified anions as are exemplified.

The monovalent weak acid anion contained in the monovalent group represented by Y ″ ^— is preferably an acid weaker than the acid generated from the [C] radiation-sensitive acid generator.

'Examples of the monovalent onium cation represented by ^+, for example, the X' above X 'illustrated cations such as monovalent onium cation contained in the monovalent group represented by ⁺ and the like.

In the above formula (3 ′), E ′ is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ²⁸ and R ²⁹ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ²⁸ , R ^29, and E ′ may represent an aliphatic heterocyclic structure having 3 to 20 ring members that is formed together with the nitrogen atom to which any two of these groups are combined with each other.

  Examples of the divalent organic group having 1 to 20 carbon atoms represented by E ′ include the same groups as those exemplified as the E group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ²⁸ and R ²⁹ include the same groups as those exemplified as the R ^J group.

Examples of the aliphatic heterocyclic structure having 3 to 20 ring members composed of any two of the groups R ²⁸ , R ²⁹ and E ′ together with the nitrogen atom to which they are bonded include the above R ^J and Examples thereof include the same groups as those exemplified as the group for E.

  Examples of the structural unit (VI) include structural units represented by the following formulas (9-1) to (9-9) (hereinafter, “structural units (VI-a-1) to (VI-a-9)”). Also).

In the above formula (9-1) ~ (9-9), ^{R U} is as defined in the above formula (9).

  Among the structural units (VI-a-1) to (VI-a-9)), the structural units (VI-a-1) to (VI-a-5) and the structural unit (VI-a-8) And the structural unit (VI-a-9) is preferred, the structural unit (VI-a-1) to the structural unit (VI-a-5) and the structural unit (VI-a-9) are more preferred, and the structural unit (VI -A-1) and (VI-a-9) are more preferred.

  In addition, examples of the structural unit (VI) include structural units represented by the following formulas.

In the above formula, R ^U and X ″ ⁺ are as defined in the above formula (9).

  [J] When the polymer component has the structural unit (VI), the upper limit of the content ratio of the structural unit (VI) is preferably 30 mol%, more preferably 25 mol%, further preferably 20 mol%, Mole% is particularly preferred.

  By setting the content ratio of the structural unit (VI) in the above range, the solubility of the [J] polymer in the developer can be adjusted more appropriately, and excessive diffusion of the acid to the unexposed area can be achieved. It is suppressed and the lithography properties can be further improved.

[Other structural units]
Examples of other structural units include a structural unit (VII) containing a carboxy group, a sulfo group or a combination thereof, a structural unit (VIII) containing a group represented by the following formula (8), a lactone structure, a cyclic carbonate structure, And a structural unit (IX) containing a sultone structure or a combination thereof.

(Structural unit (VII))
The structural unit (VII) is a structural unit including a carboxy group, a sulfo group, or a combination thereof.

  Examples of the structural unit containing a carboxy group (hereinafter also referred to as “structural unit (VII-1)”) include structural units represented by the following formulas (10-1) to (10-3) (hereinafter referred to as “structural units”). (VII-1-1) to (VII-1-3) "and the like.

In the above formulas (10-1) to (10-3), R ″ represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In the above formulas (10-1) and (10-2), R ^c1 and R ^c2 are each independently a linear or branched divalent hydrocarbon group having 1 to 6 carbon atoms, or 4 carbon atoms. Or a divalent alicyclic hydrocarbon group having 12 to 12 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms.

C 1-6 linear or branched divalent hydrocarbon group represented by R ^c1 and R ^c2 , C 4-12 divalent alicyclic hydrocarbon group, and C 6-6 Examples of the divalent aromatic hydrocarbon group of 12 include the same as those of L ^{2 in} the formula (11) described later.

  As the structural unit (VII-1-1), for example, the structural units represented by the following formulas (10-1-1) and (10-1-2) are structural units (VII-1-2): The structural unit represented by the following formula (10-1-3) is represented by the following formulas (10-2-1) and (10-2-2) as the structural unit (VII-1-3). Each structural unit may be mentioned.

  In the above formulas (10-1-1) to (10-2-2), R ″ is synonymous with the above formulas (10-1) to (10-3).

  Examples of the structural unit containing a sulfo group (hereinafter, also referred to as “structural unit (VII-2)”) include a structural unit represented by the following formula (11).

In the formula (11), R ^W is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. L ² is a single bond, an oxygen atom, a sulfur atom, a divalent linear or branched hydrocarbon group having 1 to 6 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, carbon number 6-12 divalent aromatic hydrocarbon group or ^{-C (= O) -X-R} a - a group. X is an oxygen atom, a sulfur atom or an NH group. R ^a is a single bond, a divalent linear or branched hydrocarbon group having 1 to 6 carbon atoms, ^a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, or 2 having 6 to 12 carbon atoms. Valent aromatic hydrocarbon group.

Examples of the divalent linear or branched hydrocarbon group having 1 to 6 carbon atoms represented by L ² and R ^a, is preferably a saturated hydrocarbon group such as methylene group, ethylene group, 1,3 Propylene group, 1,2-propylene group, 1,1-propylene group, 2,2-propylene group, tetramethylene group, pentamethylene group, hexamethylene group, 1-methyl-1,3-propylene group, 2-methyl Examples include -1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene group and the like.

Examples of the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms represented by L ² and R ^a, may be either monocyclic or polycyclic, in the polycyclic have a crosslinked structure Good. Examples of the monocyclic hydrocarbon group include cyclobutylene groups such as 1,3-cyclobutylene groups, cyclopentylene groups such as 1,3-cyclopentylene groups, and cyclohexylene groups such as 1,4-cyclohexylene groups. Group, a cyclooctylene group such as a 1,5-cyclooctylene group, and the like. Examples of the polycyclic hydrocarbon group include a hydrocarbon group having a 2- to 4-membered ring, a norbornylene group such as a 1,4-norbornylene group and a 2,5-norbornylene group, and a 1,5-adamantylene group. And adamantylene groups such as 2,6-adamantylene group.

Examples of the divalent aromatic hydrocarbon group having 6 to 12 carbon atoms represented by L ² and R ^a, for example, a phenylene group, such as an arylene group such as a tolylene group. In addition, the alicyclic hydrocarbon group and the aromatic hydrocarbon group do not need to be constituted only by a ring structure, and a part thereof may include a chain structure.

L ² is a single bond, a divalent linear or branched hydrocarbon group having 1 to 6 carbon atoms, ^a divalent aromatic hydrocarbon having 6 to 12 carbon atoms, or ^Ra has 1 to 6 carbon atoms. divalent ^{-C (= O) -NH-R} a is preferably a straight-chain or branched hydrocarbon group, a single bond, a methylene group, a phenylene group, -C (= O) -NH- C ( CH ₃ ) ₂ —CH ₂ — is more preferred.

  Examples of the structural unit (VII-2) include structural units represented by the following formulas (11-1) to (11-4).

In the above formula (11-1) ~ (11-4), ^{R W} is as defined in the above formula (11).

  As the structural unit (VII), the structural unit (VII-1) is preferable from the viewpoint that the solubility of the [J] polymer component in the developer can be adjusted more appropriately.

  [J] When the polymer component has the structural unit (VII), the upper limit of the content ratio of the structural unit (VII) is preferably 70 mol% with respect to all the structural units constituting the polymer component. 65 mol% is more preferable, 60 mol% is more preferable, and 55 mol% is especially preferable.

(Structural unit (VIII))
The structural unit (VIII) is a structural unit containing a group represented by the following formula (12) (hereinafter also referred to as “group (12)”). The composition (S) for forming the upper layer film can form a resist pattern with fewer development defects because the [J] polymer component has the structural unit (VIII).

In the above formula (12), R ³⁴ represents a hydrogen atom, a halogen atom, a nitro group, an alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, an acyl group, an aralkyl group or an aryl group. Some or all of the hydrogen atoms of the alkyl group, alicyclic hydrocarbon group, alkoxy group, acyl group, aralkyl group and aryl group may be substituted. R ³⁵ is —C (═O) —R ³⁶ , —S (═O) ₂ —R ³⁷ , —R ³⁸ —CN or —R ³⁹ —NO ₂ . R ³⁶ and R ³⁷ are each independently a hydrogen atom, alkyl group, fluorinated alkyl group, monovalent alicyclic hydrocarbon group, alkoxy group, cyano group, cyanomethyl group, aralkyl group or aryl group. However, R ³⁶ or R ³⁷ and R ³⁴ may be bonded to each other to form a ring structure. R ³⁸ and R ³⁹ are each independently a single bond, a methylene group or an alkylene group having 2 to 5 carbon atoms.

Examples of the halogen atom represented by R ³⁴ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom and a chlorine atom are preferable.

The alkyl group represented by R ^34, a methyl group, an ethyl group, n- propyl group, n- butyl linear alkyl group such as a group; i-propyl, i- butyl group, sec- butyl group And a branched alkyl group such as t-butyl group. As an alkyl group, a C1-C20 alkyl group is preferable.

Examples of the monovalent alicyclic hydrocarbon group represented by R ³⁴ include monocyclic alicyclic hydrocarbon groups such as a cyclopentyl group and a cyclohexyl group; and many examples such as an adamantyl group, a norbornyl group, and a tetracyclodecanyl group. And ring alicyclic hydrocarbon groups. As an alicyclic hydrocarbon group, a C3-C20 alicyclic hydrocarbon group is preferable.

The alkoxy group represented by R ^34, a methoxy group, an ethoxy group, and the like. As an alkoxy group, a C1-C20 alkoxy group is preferable.

The acyl group represented by R ^34, for example an acetyl group, a propionyl group and the like. As the acyl group, an acyl group having 2 to 20 carbon atoms is preferable.

Examples of the aralkyl group represented by R ³⁴ include a benzyl group, a phenethyl group, and a naphthylmethyl group. As the aralkyl group, an aralkyl group having 7 to 12 carbon atoms is preferable.

The aryl group represented by R ^34, a phenyl group, a tolyl group, dimethylphenyl group, a 2,4,6-trimethylphenyl group, a naphthyl group, and the like. As the aryl group, an aryl group having 6 to 10 carbon atoms is preferable.

Examples of the substituent that the alkyl group, monovalent alicyclic hydrocarbon group, alkoxy group, acyl group, aralkyl group and aryl group represented by R ³⁴ may have include a fluorine atom and a chlorine atom. A halogen atom, a hydroxyl group, a nitro group, a cyano group, etc. are mentioned.

As R ³⁴ , among these, from the viewpoint of balancing the developer solubility and the peeling resistance of the upper layer film formed from the upper layer film forming composition (S), among them, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, A C1-C5 alkoxy group and a C2-C5 acyl group are preferable, and a hydrogen atom, a methyl group, an ethyl group, and an acetyl group are more preferable.

When R ³⁵ is —C (═O) —R ³⁶ and —S (═O) ₂ —R ³⁷ , the alkyl group represented by R ⁶ and R ⁷ , a monovalent alicyclic hydrocarbon group, and an alkoxy group as the aralkyl group and the aryl group, for example, such as the same groups as those exemplified as respective groups for R ^34. Examples of the fluorinated alkyl group represented by R ³⁶ and R ³⁷ include groups in which at least one of the hydrogen atoms exemplified as the alkyl group for R ³⁴ has been substituted with a fluorine atom. Among these, as R ³⁶ and R ³⁷ , a hydrogen atom and an alkyl group are preferable, and a hydrogen atom, a methyl group, and an ethyl group are more preferable.

The group containing a ring structure formed by combining R ³⁶ or R ³⁷ and R ³⁴ with each other includes a carbon atom to which R ³³⁶ or R ³⁷ and R ³⁴ are respectively bonded, and has 5 carbon atoms having an oxo group. ~ 12 divalent alicyclic hydrocarbon groups are preferred.

When R ³⁵ is —R ³⁸ —CN and —R ³⁹ —NO ₂ , R ³⁸ and R ³⁹ are preferably a single bond, a methanediyl group or an ethanediyl group.

  As the group (12), groups represented by the following formulas (12-1) to (12-8) (hereinafter also referred to as “groups (12-1) to (12-8)”) are preferable.

  In the above formulas (12-1) to (12-8), * represents a binding site.

  Examples of the structural unit (VIII) include (meth) acrylic acid ester derivatives having a group (12), (meth) acrylamide derivatives, vinyl ether derivatives, olefin derivatives, structural units derived from styrene derivatives, and the like. In this, the structural unit derived from the (meth) acrylic acid ester derivative which has group (12) from a copolymerizable viewpoint of the monomer which gives structural unit (VII) is preferable. That is, as the structural unit (VIII), a structural unit represented by the following formula (12-a) (hereinafter also referred to as “structural unit (VIII-a)”) is preferable.

In the above formula (12-a), R ^S represents a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. R ^T is a (m + 1) -valent linking group. R ¹⁴ and R ¹⁵ are as defined in the above formula (12). m is an integer of 1-3. If R ³⁴ and ^{R 35} are a plurality of each of the plurality of ^{R 34} and ^{R 35} may be the same as or different from each other.

As ^RS , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable, from the viewpoint of copolymerization of the monomer that gives the structural unit (12-a).

As the (m + 1) -valent linking group represented by ^RT , for example, as a divalent linking group (when n is 1), an alkanediyl group, a divalent alicyclic hydrocarbon group, an alkenediyl group, an arenediyl group Groups and the like. Note that some or all of the hydrogen atoms contained in these groups may be substituted with a halogen atom such as a fluorine atom or a chlorine atom, a cyano group, or the like.

  Examples of the alkanediyl group include a methanediyl group, an ethanediyl group, a propanediyl group, a butanediyl group, a hexanediyl group, and an octanediyl group. As the alkanediyl group, an alkanediyl group having 1 to 8 carbon atoms is preferable.

  Examples of the divalent alicyclic hydrocarbon group include monocyclic alicyclic hydrocarbon groups such as cyclopentanediyl group and cyclohexanediyl group; polycyclic alicyclic hydrocarbons such as norbornanediyl group and adamantanediyl group Etc. As a bivalent alicyclic hydrocarbon group, a C5-C12 alicyclic hydrocarbon group is preferable.

  Examples of the alkenediyl group include an ethenediyl group, a propenediyl group, and a butenediyl group. The alkenediyl group is preferably an alkenediyl group having 2 to 6 carbon atoms.

  Examples of the arenediyl group include a phenylene group, a tolylene group, and a naphthylene group. As the arenediyl group, an arenediyl group having 6 to 15 carbon atoms is preferable.

Among these, as ^RT , an alkanediyl group, a divalent alicyclic hydrocarbon group is preferable, an alkanediyl group having 1 to 4 carbon atoms, and a divalent alicyclic hydrocarbon group having 6 to 11 carbon atoms. Is more preferable. When ^RT is a divalent alicyclic hydrocarbon group, it is preferable from the viewpoint of improving the water repellency of the resulting upper layer film.

  As the structural unit (VIII-a), structural units represented by the following formulas (12-a-1) to (12-a-8) (hereinafter referred to as “structural units (VIII-a-1) to (VIII-)” a-8) ") is preferred.

In the above formulas (12-a-1) to (12-a-10), R ^S has the same ^{meaning as} in the above formula (12-a).

  [J] When the polymer component has the structural unit (VIII), the upper limit of the content ratio of the structural unit (VIII) is preferably 70 mol% with respect to all the structural units constituting the [J] polymer component. 65 mol% is more preferable, 60 mol% is more preferable, and 55 mol% is especially preferable.

  By setting the content of the structural unit (VIII) in the above range, the solubility of the [J] polymer in the developer can be adjusted more appropriately, and a resist pattern with fewer development defects can be formed. Can do.

(Structural unit (IX))
The structural unit (IX) is a structural unit including a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof.

  Examples of the structural unit (IX) include the structural unit (III) of the [B] polymer of the radiation sensitive resin composition (Z) described above.

  As the structural unit (IX), a structural unit containing a lactone structure is preferred, a structural unit containing a butyrolactone structure is more preferred, and a structural unit derived from butyrolactone-yl (meth) acrylate is more preferred.

  [J] When the polymer component has a structural unit (IX), the upper limit of the content ratio of the structural unit (IX) is preferably 70 mol% with respect to all the structural units constituting the [J] polymer component. 65 mol% is more preferable, 60 mol% is more preferable, and 55 mol% is especially preferable.

  [J] The polymer component may have other structural units in addition to the structural units (IV) to (IX). Examples of other structural units include a structural unit containing a non-dissociable chain hydrocarbon group or aromatic hydrocarbon group, and a structural unit containing a hydroxy group. Examples of the non-dissociable chain hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, a benzyl group, and a naphthylmethyl group. As an upper limit of the content rate of another structural unit, 60 mol% is preferable with respect to all the structural units which comprise a [J] polymer component, and 55 mol% is more preferable.

  [J1] The upper limit of the mass ratio of the polymer (b) to the polymer (a) in the polymer component is preferably 50/50, more preferably 45/55, still more preferably 40/60, and 35/65. Particularly preferred is 30/70, most preferred. By setting the mass ratio of the polymer (a) to the polymer (b) within the above range, the upper film forming surface (S) containing the polymer component [J1] Both aqueous properties and development defect suppression can be further enhanced.

[Other polymers]
The composition for forming an upper layer film (S) may contain a polymer other than the polymer (a) and the polymer (b) as the [J1] polymer component. The composition for forming an upper layer film (S) may contain a polymer other than the polymer (c) as the [J2] polymer component. Examples of the other polymer include a polymer having no structural unit (IV) and no structural unit (V), and the polymer includes at least one of the structural units (VI) to (IX) and other structural units. A polymer etc. are mentioned.

[J] When the polymer contains a fluorine atom, the lower limit of the fluorine atom content in the [J] polymer is preferably 2% by mass, more preferably 5% by mass, further preferably 7% by mass, 10% by mass is particularly preferred. As an upper limit of the said fluorine atom content rate, 30 mass% is preferable, 25 mass% is more preferable, 20 mass% is further more preferable, 15 mass% is especially preferable. [J] By setting the fluorine atom content of the polymer in the above range, both the water repellency and the development defect suppressing property of the upper layer film surface can be enhanced. [J] The fluorine atom content (% by mass) in the polymer was determined by determining the structure of the polymer constituting the [J] polymer by ¹ H-NMR, ¹³ C-NMR, ¹⁹ F-NMR, etc. It can be calculated from

<[J] Polymer Synthesis Method>
[J] The polymer (a), polymer (b), polymer (c), and other polymers constituting the polymer are, for example, a predetermined monomer, an appropriately selected polymerization initiator or chain transfer It can be synthesized by polymerization such as radical polymerization in a polymerization solvent in the presence of an agent.

Examples of the polymerization solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, ethylene glycol, diethylene glycol, and propylene glycol;
Cyclic ethers such as tetrahydrofuran and dioxane;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl Alkyl ethers of polyhydric alcohols such as ethers;
Alkyl ether acetates of polyhydric alcohols such as ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol monomethyl ether acetate;
Aromatic hydrocarbons such as toluene and xylene;
Ketones such as acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol;
Ethyl acetate, butyl acetate, methyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy-3-methylbutane And esters such as methyl acid, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, and the like. Of these, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ketones or esters are preferred. In addition, the said polymerization solvent can use 1 type (s) or 2 or more types.

  [J] The lower limit of the Mw of the polymer is preferably 2,000, more preferably 3,000, still more preferably 4,000, and particularly preferably 5,000. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000.

  [J] When the polymer is a [J1] polymer, the lower limit of the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer (a) is preferably 2,000. Is more preferable, 4,000 is further more preferable, and 5,000 is particularly preferable. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000. Moreover, as a minimum of Mw of a polymer (b), 2,000 is preferable, 3,000 is more preferable, 4,000 is further more preferable, 5,000 is especially preferable. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000.

  [J] When the polymer is a [J2] polymer, the lower limit of the Mw of the polymer (c) is preferably 2,000, more preferably 3,000, still more preferably 4,000, and 5,000. Is particularly preferred. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000.

  [J] By setting the Mw of the polymer in the polymer within the above range, the solubility of the polymer in the developer can be appropriately adjusted, and as a result, the occurrence of development defects in the resist pattern can be further suppressed. Can do.

  [J] The upper limit of the Mw / Mn ratio of the polymer is preferably 5, more preferably 3, more preferably 2.5, and particularly preferably 2. The lower limit of the ratio is usually 1 and preferably 1.1.

  [J] When the polymer is a [J1] polymer, the upper limit of the ratio (Mw / Mn) of the polymer (a) to the polystyrene-equivalent number average molecular weight (Mw) by GPC of Mw is preferably 5. .5 is more preferable, 3.0 is more preferable, and 2.5 is particularly preferable. The lower limit of the ratio is usually 1 and preferably 1.1. Further, the upper limit of the Mw / Mn ratio of the polymer (b) is preferably 5, more preferably 3, more preferably 2.5, and particularly preferably 2. The lower limit of the ratio is usually 1 and preferably 1.1.

  [J] When the polymer is a [J2] polymer, the upper limit of the Mw / Mn ratio of the polymer (c) is preferably 5, more preferably 3.5, still more preferably 3.0. 5 is particularly preferred. The lower limit of the ratio is usually 1 and preferably 1.1.

  By setting the Mw / Mn ratio in the above range, the solubility of the polymer in the developer can be further increased, and as a result, both the water repellency and the development defect suppression of the upper film surface can be further enhanced. .

  The composition for forming an upper layer film (S) is more preferable as it contains less impurities such as halogen ions and metals. By reducing the impurities, it is possible to improve the coating property as the upper layer film-forming composition (S) and the uniform solubility of the upper layer film in the developer containing the organic solvent. Examples of methods for purifying the [J] polymer to reduce impurities include chemical purification methods such as washing with water, liquid-liquid extraction, and demetalization filter passage, these chemical purification methods and ultrafiltration, and centrifugation. A combination with a physical purification method such as

  [J] The lower limit of the content of the polymer is preferably 90% by mass, more preferably 95% by mass, and still more preferably 99% by mass with respect to the total solid content in the upper layer film-forming composition (S). . The upper limit of the content is usually 100% by mass. Here, “total solid content” refers to components other than the solvent of the composition for forming an upper layer film (S).

<[P] solvent>
The composition for forming an upper layer film (S) contains a [P] solvent. The [P] solvent is not particularly limited as long as it can dissolve or disperse the [J] polymer and other components of the [K] acid diffusion inhibiting compound contained as necessary.

  [P] Examples of the solvent include the solvents exemplified as the organic solvent contained in the developer in the developing step. The composition for forming an upper layer film (S) can contain [P] solvent alone or in combination of two or more.

[P] The solvent is preferably an ester solvent, a ketone solvent, an amide solvent, an ether solvent, an alcohol solvent, a hydrocarbon solvent, or a combination thereof.
Examples of these organic solvents include one or more of the solvents exemplified as the [C] solvent of the above-mentioned radiation-sensitive resin composition.

  Among these, the [P] solvent is preferably an alcohol solvent, an ether solvent or a combination thereof from the viewpoint of suppressing elution of the resist film component. As the alcohol solvent, a monovalent alcohol having 7 or less carbon atoms is more preferable. As the ether solvent, an alkyl ether of a polyhydric alcohol is more preferable.

  As a minimum of content of the above-mentioned alcohol solvent to a solvent in the above-mentioned composition for upper layer film formation, 70 mass% is preferred, 75 mass% is more preferred, and 80 mass% is still more preferred. As a minimum of content of the above-mentioned ether system solvent to a solvent in the above-mentioned composition for upper layer film formation, 70 mass% is preferred, 75 mass% is more preferred, and 80 mass% is still more preferred. The lower limit of the total content of the alcohol solvent and the ether solvent relative to the solvent in the upper layer film-forming composition is preferably 70% by mass, more preferably 90% by mass, and still more preferably 95% by mass.

<[K] Acid Diffusion Inhibiting Compound>
The upper layer film-forming composition (S) preferably contains a [K] acid diffusion inhibiting compound regardless of the presence or absence of the structural unit (VI) of the [J] polymer. When the [J] polymer does not have the structural unit (VI), the composition for forming an upper layer film (S) contains a [K] acid diffusion inhibiting compound. [K] The acid diffusion inhibiting compound acts on the exposed portion of the resist film below the upper layer film to be formed, so that excessive diffusion of the acid to the unexposed portion is suppressed, and the lithography properties can be improved. [K] The acid diffusion inhibiting compound includes a [k1] compound, a [k2] compound, a [k3] compound, or a combination thereof.

  [K1] The compound is a compound represented by the following formula (1).

In the above formula (1), R ^A and R ^B are each independently a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other to form a nitrogen atom to which they are bonded. Represents an aliphatic heterocyclic structure having 3 to 20 ring members. R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms.

The monovalent organic group having 1 to 20 carbon atoms represented by ^{R A} and ^{R B,} for example, a monovalent chain-like hydrocarbon group having 1 to 20 carbon atoms, monovalent cycloaliphatic of 3 to 20 carbon atoms A cyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group containing a heteroatom-containing group at the terminal between carbon-carbon of these hydrocarbon groups or on the side of the bond, Examples include a group in which part or all of the hydrogen atoms are substituted with a substituent.

  The hetero atom-containing group refers to a group having a divalent or higher valent hetero atom in the structure. The hetero atom-containing group may have one hetero atom or two or more hetero atoms.

  The divalent or higher valent hetero atom of the hetero atom-containing group is not particularly limited as long as it is a hetero atom having a valence of 2 or higher. For example, an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a phosphorus atom And boron atoms.

Examples of the substituent for substituting part or all of the hydrogen atoms of these groups include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom;
Examples thereof include a hydroxy group, a carboxy group, a cyano group, a nitro group, an acyl group, an acyloxy group, an alkoxy group, a halogenated alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, and an oxo group (═O).

Examples of the aliphatic heterocyclic structure having 3 to 20 ring members constituted with the nitrogen atom to which the groups R ^A and R ^B are combined with each other are as follows:
Azacycloalkane structures such as an azacyclopropane structure, an azacyclobutane structure, an azacyclopentane structure, an azacyclohexane structure, an azacyclooctane structure, an azacyclodecane structure, an azanorbornane structure, an azaadamantane structure;
An azaoxacycloalkane structure such as an azaoxacyclopentane structure, an azaoxacyclohexane structure, an azaoxacyclooctane structure, an azaoxanorbornane structure;
Examples thereof include diazacyclopentane structures, diazacyclohexane structures, diazacyclooctane structures, diazacyclodecane structures, and diazacycloalkane structures such as diazanorbornane structures.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^1, for example, such as the same groups as those exemplified as the groups of R ^{1 'and} the like.

  Examples of the chain hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group; an alkenyl group such as an ethenyl group, a propenyl group, a butenyl group and a pentenyl group; an ethynyl group and a propynyl group Alkynyl groups such as butynyl group and pentynyl group.

  Examples of the alicyclic hydrocarbon group include monocyclic alicyclic saturated hydrocarbon groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclohexyl group; norbornyl group, adamantyl group, tricyclodecyl group, tetracyclododecyl Polycyclic alicyclic saturated hydrocarbon group such as a group; monocyclic alicyclic unsaturated hydrocarbon group such as cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group; norbornenyl group, tricyclodecenyl And polycyclic alicyclic unsaturated hydrocarbon groups.

  Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group and anthryl group; aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group and anthrylmethyl group. It is done.

  Examples of the [k1] compound include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazolebenzimidazole, N -(T-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine, N-t-butoxy Examples include carbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine, N- (undecan-1-ylcarbonyloxyethyl) morpholine, and the like.

  [K2] The compound is a compound represented by the following formula (2).

In the above formula (2), X ⁺ is a monovalent onium cation. Y ⁻ is a monovalent weak acid anion.

Examples of the monovalent onium cation represented by X ⁺ include a sulfonium cation, an iodonium cation, an ammonium cation, and an oxonium cation.

Examples of the monovalent weak acid anion represented by Y ⁻ include a monovalent carboxylate anion and a monovalent sulfonamide anion.

Examples of the monovalent carboxylate anion represented by Y ⁻ include a salicylate anion. Examples of the monovalent sulfonamide anion represented by Y- include trifluoromethylsulfonamide ion.

The monovalent weak acid anion represented by Y ⁻ is preferably a weaker acid than the acid generated from the [C] radiation-sensitive acid generator.

  The above-mentioned [k2] compound includes a photo-disintegrating base which is a basic compound and is a compound which is exposed to light to generate a weak acid and lowers the basicity. Examples of the photodegradable base include the same ones as mentioned above for the [E] acid diffusion controller.

  Moreover, as said [k2] compound, the following compounds are mentioned, for example.

  [K3] The compound is a compound represented by the following formula (3).

In the above formula (3), R ¹⁸ , R ¹⁹ and R ²⁰ are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, an aryl group or an aralkyl group. .

  Examples of the [k3] compound include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; aromatic amines such as aniline.

  [E] As the acid diffusion controller, in addition to the above [k1] compound, [k2] compound and [k3] compound, for example, a compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (II ) ”, Compounds having three nitrogen atoms (hereinafter also referred to as“ nitrogen-containing compound (III) ”), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

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

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

  Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. It is done.

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

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

  [K] As the acid diffusion inhibiting compound, tetrabutylammonium camphorsulfonic acid and triphenylsulfonium salicylic acid are preferable.

  When the composition for forming an upper layer film (S) contains a [K] acid diffusion inhibiting compound, the lower limit of the content of the [K] acid diffusion inhibiting compound is 0 with respect to 100 parts by mass of the [J] polymer. 0.1 parts by mass is preferable, 0.5 parts by mass is more preferable, and 0.8 parts by mass is more preferable. As an upper limit of the said content, 20 mass parts is preferable, 15 mass parts is more preferable, and 12 mass parts is further more preferable. [K] By setting the content of the acid diffusion inhibiting compound in the above range, film loss in resist pattern formation can be further reduced. [K] The acid diffusion inhibiting compound can be used alone or in combination of two or more.

<Other ingredients>
The composition for forming an upper layer film (S) may contain other components in addition to the [J] polymer, the [P] solvent, and the [K] acid diffusion inhibiting compound. Examples of other components include a surfactant.

[Surfactant]
The surfactant is a component for improving the coating property of the composition for forming an upper layer film (S). A commercial item can also be used as said surfactant. As an upper limit of content of the said surfactant, 5 mass parts is preferable with respect to 100 mass parts of [J] polymers, and 2 mass parts is more preferable.

<Method for Preparing Composition for Forming Upper Layer Film (S)>
The upper layer film-forming composition (S) is prepared by mixing, for example, the [J] polymer and, if necessary, other components such as the [K] acid diffusion inhibiting compound with the [P] solvent, The obtained mixture can be prepared by filtering through a membrane filter of about 0.2 μm. As a minimum of solid content concentration of composition (S) for upper layer film formation, 0.1 mass% is preferred, 0.3 mass% is more preferred, and 0.5 mass% is still more preferred. As an upper limit of the said solid content concentration, 30 mass% is preferable, 20 mass% is more preferable, and 10 mass% is further more preferable.

  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.

[Measurement of Mw and Mn]
Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) under the following conditions.
GPC column: 2 Tosoh “G2000HXL”, 1 “G3000HXL” and 1 “G4000HXL” Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Column temperature: 40 ° C.
Standard material: Monodisperse polystyrene Detector: Differential refractometer

[ ¹ H-NMR, ¹³ C-NMR analysis and ¹⁹ F-NMR analysis]
For the ¹ H-NMR and ¹³ C-NMR analysis of the polymer, a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.) was used, acetone-d6 was used as a measurement solvent, and tetramethylsilane (TMS). Was measured as an internal standard.

<Preparation of radiation-sensitive resin composition>
The radiation sensitive resin composition used for resist film formation was prepared by the following method.

<Synthesis of [A] polymer and [B] polymer>
The monomers used for the synthesis of [A] polymer and [B] polymer are shown below.

  The monomers (M-1) to (M-3) are structural units (II), the monomer (M-4) is a structural unit having a hydroxy group, the monomers (M-5) and (M-6) represents a structural unit (III), (M-7) represents a structural unit (I), and (M-8) represents a structural unit containing a non-dissociable monovalent alicyclic hydrocarbon group. Give each.

[[A] Synthesis of polymer]
[Synthesis Example 1] Synthesis of polymer (A-1) As shown in Table 1, 50 mol% of the compound (M-7) and 50 mol% of the compound (M-8) were dissolved in 20 g of 2-butanone, and A monomer solution was prepared by dissolving 7 mol% of azobisisobutyronitrile as a polymerization initiator with respect to all monomers. The total mass of the monomers used was 100 g. Next, a 500 mL three-necked flask containing 100 g of 2-butanone was heated to 80 ° C. with stirring in a nitrogen atmosphere, and the prepared monomer solution was added dropwise over 3 hours. After completion of the dropwise addition, the polymerization reaction was carried out by heating at 80 ° C. for 3 hours. After completion of the polymerization reaction, the reaction solution was cooled to room temperature. After the reaction solution was transferred to a separatory funnel, the reaction solution was uniformly diluted with 300 g of n-hexane, and 1200 g of methanol was added and mixed. Next, 60 g of distilled water was added, and the mixture was further stirred and allowed to stand for 30 minutes. Next, the lower layer was recovered, and the solvent was replaced with propylene glycol monomethyl ether acetate to obtain a propylene glycol monomethyl ether acetate solution containing the polymer (A-1) as a solid content (yield 75.5%). ). Mw of the polymer (A-1) was 5,000, and Mw / Mn was 1.50.

[[B] Synthesis of polymer]
Synthesis Example 2 Synthesis of Polymer (B-1) As shown in Table 2 below, compound (M-2) 50 mol%, compound (M-4) 25 mol%, and compound (M-5) 25 mol % Was dissolved in 40 g of 2-butanone, and 3 mol% of azobisisobutyronitrile as a polymerization initiator was dissolved with respect to all monomers to prepare a monomer solution. The total mass of the monomers used was 100 g. Next, a 500 mL three-necked flask containing 100 g of 2-butanone was heated to 80 ° C. with stirring in a nitrogen atmosphere, and the prepared monomer solution was added dropwise over 3 hours. After completion of the dropwise addition, the polymerization reaction was carried out by heating at 80 ° C. for 3 hours. After completion of the polymerization reaction, the reaction solution was cooled to room temperature, poured into 2000 g of methanol, and the precipitated solid was separated by filtration. The solid separated by filtration was washed twice with 400 g of methanol, filtered, and then dried under reduced pressure at 50 ° C. for 15 hours to synthesize a polymer (B-1) (yield 66.5%). Mw of the polymer (B-1) was 9,100, and Mw / Mn was 1.75.

[Synthesis Example 3] Synthesis of polymer (B-2) As shown in Table 2 below, compound (M-1) 40 mol%, compound (M-3) 10 mol%, compound (M-4) 20 mol% %, Compound (M-5) 20 mol%, compound (M-6) 10 mol%, azobisisobutyronitrile 3 mol% as a polymerization initiator was dissolved in 100 g of 2-butanone with respect to all monomers. . The total mass of the monomers used was 100 g. Next, a 500 mL three-necked flask containing 100 g of 2-butanone was heated to 80 ° C. with stirring in a nitrogen atmosphere, and the prepared monomer solution was added dropwise over 3 hours. After completion of the dropwise addition, the polymerization reaction was carried out by heating at 80 ° C. for 3 hours. After completion of the polymerization reaction, the polymerization solution was dropped into 2000 g of methanol, and the precipitated solid was separated by filtration. The solid separated by filtration was washed twice with 400 g of methanol, filtered, and dried under reduced pressure at 50 ° C. for 17 hours to obtain a white powdery polymer (B-2) (yield 70.5%). ). Mw of the polymer (B-2) was 8700, and Mw / Mn was 1.78.

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

[[C] Radiation sensitive acid generator]
C-1: Compound represented by the following formula (C-1) C-2: Compound represented by the following formula (C-2)

[[E] acid diffusion controller]
E-1: Compound represented by the following formula (E-1) E-2: Compound represented by the following formula (E-2)

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

[Radiation-sensitive resin composition (Z-1)]
As shown in Table 3 below, [A] 3 parts by mass of polymer (A-1), [B] 100 parts by mass of polymer (B-1), [C] radiation sensitive acid generator (C-1) 10 parts by mass, 8.7 parts by mass of [E] acid diffusion controlling agent (E-1), and [D] 2,640 parts by mass of solvent (D-1), (D-2) 1,130 parts by mass and (D -3) 30 mass parts was mixed, and the radiation sensitive resin composition (Z-1) was prepared by filtering the obtained mixture with a membrane filter with the hole diameter of 0.2 micrometer.

[Preparation of Radiation Sensitive Resin Compositions (Z-2) to (Z-4)]
The feeling of (Z-2) to (Z-4) is the same as that of the radiation sensitive resin composition (Z-1) 1 except that the components of the types and blending amounts shown in Table 3 below are used. A radiation resin composition was prepared.

<Synthesis of [J] polymer for composition for forming upper layer film>
[J] Monomers used for polymer synthesis are shown below.

  The monomers (M-9) to (M-11) are structural units (IV), the monomers (M-12) and (M-13) are structural units (VI), (M-14). ) Gives structural unit (IX), and monomers (M-15) and (M-16) give structural unit (V).

[Synthesis Example 4]
As shown in Table 4 below, 25 mol% of the compound (M-9) and 75 mol% of the compound (M-10) were dissolved in 200 g of 2-butanone. The total mass of the monomers used was 100 g. Next, 4.12 g (5 mol% with respect to the total amount of monomers) of 2,2′-azobis- (methyl 2-methylpropionate) as a radical polymerization initiator was added to prepare a monomer solution. did. A 1,000-mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, and then the flask was heated to 80 ° C. while stirring with a magnetic stirrer, and the prepared monomer solution was added using a dropping funnel for 3 hours. It was dripped over. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water and cooled to 30 ° C. or lower. A polymerization reaction solution cooled in 2,000 g of methanol was added, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 400 g of methanol, filtered, and dried at 60 ° C. for 17 hours to obtain a white powdery polymer (J-1) (yield 77.0%). . Mw of the obtained polymer (J-1) was 9,200, and Mw / Mn was 1.60.

[Synthesis Examples 5 to 8]
Polymers (J-2) to (J-5) were respectively synthesized in the same manner as in Synthesis Example 4 except that the types and amounts of monomers listed in Table 4 were used. The total mass of the monomers used was 100 g. In Table 1, “-” indicates that the corresponding component was not used. Table 4 shows the yield, Mw, and Mw / Mn values of the obtained polymer.

[Synthesis Example 9]
As shown in Table 4 below, 50 mol% of the compound (M-15) and 50% of the compound (M-16) were dissolved in 200 g of 2-butanone. The total mass of the monomers used was 100 g. Next, 2.99 g of 2,2′-azobis- (methyl 2-methylpropionate) as a radical polymerization initiator (3 mol% based on the total amount of monomers) was added to prepare a monomer solution. did. A 1,000-mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, and then the flask was heated to 80 ° C. while stirring with a magnetic stirrer, and the prepared monomer solution was added using a dropping funnel for 3 hours. It was dripped over. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. Next, the obtained polymerization reaction liquid was transferred to a separatory funnel, and 56 g of methanol and 240 g of heptane were added to the separatory funnel to carry out separation purification. After separation, the lower layer solution was recovered. The recovered lower layer liquid was replaced with 4-methyl-2-pentanol to obtain a liquid containing the polymer (J-1). 0.5 g of the liquid containing the polymer (J-1) is placed on an aluminum dish and heated on a hot plate heated to 155 ° C. for 30 minutes, and then the liquid containing the polymer (J-1) is obtained from the mass of the residue. The solid content concentration was calculated, and the value of the solid content concentration was used in the subsequent preparation of the composition for forming an upper layer film and the yield calculation. The yield of the obtained polymer (J-6) was 71.2%, Mw was 11,000, and Mw / Mn was 1.65.

[Synthesis Example 10]
A polymer (J-7) was synthesized in the same manner as in Synthesis Example 9, except that the types and amounts of monomers listed in Table 4 were used. The total mass of the monomers used was 100 g. In Table 4, “-” indicates that the corresponding component was not used. Table 4 shows the yield, Mw, and Mw / Mn values of the obtained polymer.

<Preparation of composition for forming upper layer film>
The [K] acid diffusion inhibiting compound and the [P] solvent used for the preparation of the composition for forming the upper layer film are shown below.

[[K] acid diffusion inhibiting compound]
K-1: Compound represented by the following formula (K-1) K-2: Compound represented by the following formula (K-2) K-3: Compound represented by the following formula (K-3) E- 4: Compound represented by the following formula (K-4)

[[P] solvent]
P-1: 4-methyl-2-pentanol P-2: 2-heptanol P-3: Diisoamyl ether P-4: n-decane P-5: γ-butyrolactone

[Composition for forming upper layer film (S-1)]
[J] A liquid containing 95 parts by mass of polymer (J-1) as a polymer and 5 parts by mass of polymer (J-6), and 11,350 parts by mass of (P-1) as a solvent And (P-3) 2,840 mass parts was mixed and the obtained mixture was filtered with a 0.2 micrometer membrane filter, and the composition for upper film | membrane formation (S-1) was prepared.

[Preparation of Upper Film Formation Compositions (S-2) to (S-13)]
The upper layer film-forming compositions (S-2) to (S-13) are the same as the upper layer film-forming composition (S-1) except that the types and contents shown in Table 5 below are used. Was prepared. The value of the mass content (% by mass) of fluorine atoms in the [J] polymer of the composition for forming an upper layer film is shown in Table 5 together.

<Evaluation>
As shown in Table 6 below, combinations of the types of the prepared radiation sensitive resin compositions (Z-1) to (Z-4) and upper layer film forming compositions (S-1) to (S-13) Various evaluations shown below were performed. In addition, “-” in Table 6 indicates that the composition for forming an upper layer film was not used. The evaluation results are shown in Table 6 below.

[Backward contact angle]
The receding contact angle value of water on the upper film surface was measured. A radiation-sensitive resin composition was applied onto an 8-inch silicon wafer, PB (90 ° C., 60 seconds), and then cooled at 23 ° C. for 30 seconds to form a resist film having a thickness of 90 nm. Next, the composition for forming an upper layer film was spin-coated, and PB was performed on a hot plate at 90 ° C. for 60 seconds to form an upper layer film having a thickness of 30 nm. Thereafter, using a contact angle meter (DSA-10, manufactured by KRUS), the receding contact angle was quickly measured by the following procedure in an environment of room temperature 23 ° C., humidity 45%, and normal pressure. First, the wafer stage position of the contact angle meter was adjusted, and the wafer was set on the adjusted stage. Next, water was injected into the needle, and the position of the needle was finely adjusted to an initial position where water droplets can be formed on the set wafer. Thereafter, water was discharged from the needle to form a 25 μL water droplet on the wafer. The needle was once withdrawn from the water droplet, and the needle was pulled down again at the initial position and placed in the water droplet. Subsequently, a water droplet was sucked with a needle at a speed of 10 μL / min for 90 seconds, and at the same time, the contact angle was measured once per second for a total of 90 times. Among these, the average value for the contact angle for 20 seconds from the time when the measured value of the contact angle was stabilized was calculated and set as the receding contact angle (unit: degree (°)). When the receding contact angle was 70 ° or more, it was judged as “good”, and when it was less than 70 °, it was judged as “bad”.

[DOF (focus margin)]
An underlayer antireflection film (ARC66, manufactured by Nissan Chemical Industries, Ltd.) was applied on a 12-inch recon wafer using a spin coater (CLEAN TRACK Lithius Proi, manufactured by Tokyo Electron), and then heated at 205 ° C. for 60 seconds. A lower antireflection film having a thickness of 105 nm was formed. Next, using the spin coater, the radiation sensitive resin composition was applied, PB (90 ° C., 60 seconds), and then cooled at 23 ° C. for 30 seconds to form a resist film having a thickness of 90 nm. Next, using the spin coater, the upper layer film-forming composition was applied, PB (90 ° C., 60 seconds), and then cooled at 23 ° C. for 30 seconds to form an upper layer film having a thickness of 30 nm. Next, using an ArF immersion exposure apparatus (S610C, manufactured by Nikon), exposure was performed through a mask for forming a pattern of 45 nm holes / 800 nm pitch under the optical conditions of NA: 1.30 and Crosssole. Next, PEB was performed at 90 ° C. for 60 seconds on the “Lithius Pro-i” hot plate, cooled at 23 ° C. for 30 seconds, and then subjected to paddle development for 30 seconds using butyl acetate as a developer.

  Next, after rinsing with 4-methyl-2-pentanol for 7 seconds, spin drying was performed at 2,000 rpm for 15 seconds to form a resist pattern having a 45 nm hole / 800 nm pitch. At this time, the exposure amount for forming a 45 nm hole was determined as the optimum exposure amount (Eop). The obtained resist pattern was measured using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, CG4000). The focus fluctuation width when the hole pattern size to be formed is within ± 10% of 45 nm was defined as DOF. It was judged that the larger the DOF value, the smaller the variation in patterning performance with respect to the focus change and the better.

[CDU performance]
By applying a lower antireflection film (ARC66, manufactured by Nissan Chemical Industries, Ltd.) on a 12-inch recon wafer using a spin coater (CLEAN TRACK Lithius Proi, manufactured by Tokyo Electron), heating at 205 ° C. for 60 seconds. A lower antireflection film having a thickness of 105 nm was formed. Next, using the spin coater, the radiation sensitive resin composition was applied, PB (90 ° C., 60 seconds), and then cooled at 23 ° C. for 30 seconds to form a resist film having a thickness of 90 nm. Next, using the spin coater, the upper layer film-forming composition was applied, PB (90 ° C., 60 seconds), and then cooled at 23 ° C. for 30 seconds to form an upper layer film having a thickness of 30 nm. Next, using an ArF immersion exposure apparatus (S610C, manufactured by Nikon Corporation), exposure was performed through a mask for pattern formation of 45 nm holes / 90 nm pitch under NA: 1.30 and Crosssole optical conditions. Next, PEB was performed at 90 ° C. for 60 seconds on the “Lithius Pro-i” hot plate, cooled at 23 ° C. for 30 seconds, and then subjected to paddle development for 30 seconds using butyl acetate as a developer. Next, after rinsing with 4-methyl-2-pentanol for 7 seconds, spin drying was performed at 2,000 rpm for 15 seconds to form a resist pattern with 45 nm holes / 90 nm pitch. The obtained resist pattern was measured using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, CG4000). The variation of the hole diameter (3σ) for 1800 hole patterns formed was defined as CDU. A case where CDU was 6.5 nm or less was judged as “good”, and a case where CDU exceeded 6.5 nm was judged as “bad”.

[LWR Performance] Confirmation A lower antireflection film (ARC66, manufactured by Nissan Chemical Industries, Ltd.) was applied on a 12-inch recon wafer using a spin coater (CLEAN TRACK Lithius Proi, manufactured by Tokyo Electron), and then at 60 ° C. at 60 ° C. A lower antireflection film having a film thickness of 105 nm was formed by heating for 2 seconds. Next, using the spin coater, the radiation sensitive resin composition was applied, PB (90 ° C., 60 seconds), and then cooled at 23 ° C. for 30 seconds to form a resist film having a thickness of 90 nm. Next, using the spin coater, the upper layer film-forming composition was applied, PB (90 ° C., 60 seconds), and then cooled at 23 ° C. for 30 seconds to form an upper layer film having a thickness of 30 nm. Next, using an ArF immersion exposure apparatus (S610C, manufactured by Nikon Corporation), exposure was performed through a mask for pattern formation with a 45 nm space / 100 nm pitch under optical conditions of NA: 1.30 and Crosspore. Next, PEB was performed for 60 seconds at 90 ° C. on the hot plate of “Lithius Pro-i”. Then, after cooling at 23 ° C. for 30 seconds, paddle development was performed for 30 seconds using butyl acetate as a developer. Next, after rinsing with 4-methyl-2-pentanol for 7 seconds, spin drying was performed at 2,000 rpm for 15 seconds to form a 45 nm space / 100 nm pitch resist pattern. The obtained resist pattern was measured using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, CG4000). The space width variation (3σ) at 20 formed space patterns was defined as LWR. When the LWR was 5.5 nm or less, it was judged as “good”, and when it exceeded 5.5 nm, it was judged as “bad”.

[Bridge defect suppression and disconnection defect suppression]
The number of occurrences of bridge defects and disconnection defects in the resist pattern obtained by exposing and developing the resist film on which the upper layer film was formed was evaluated. A 12-inch silicon wafer surface was spin-coated using a coating / developing apparatus (“Lithius Pro-i” from Tokyo Electron) with a composition for forming an underlayer antireflection film (“ARC66” from Nissan Chemical Co., Ltd.) By performing PB, a lower antireflection film having an average thickness of 105 nm was formed. Next, using the above coating / developing apparatus, the radiation-sensitive resin composition (α) was spin-coated, PB was performed at 90 ° C. for 60 seconds, and then cooled at 23 ° C. for 30 seconds, so that the average thickness was 90 nm. The resist film was formed. Then, the composition for upper layer film formation was apply | coated on this resist film, and the upper layer film of average thickness 30nm was formed by performing PB for 60 second at 90 degreeC.

  Next, using an ArF immersion exposure apparatus (“S610C” manufactured by NIKON), exposure was performed through a mask for pattern formation of 45 nm line / 90 nm pitch under the optical conditions of NA: 1.30 and Dipole. Next, PEB was performed at 90 ° C. for 60 seconds on the hot plate of the coating / developing apparatus, cooled at 23 ° C. for 30 seconds, and then subjected to paddle development for 30 seconds using butyl acetate as a developer. Thereafter, spin drying was performed by swinging off at 2,000 rpm for 15 seconds to obtain a substrate on which a resist pattern was formed. The substrate on which the obtained resist pattern is formed is subjected to defect inspection using a defect inspection apparatus (“KLA2810” from KLA-Tencor), and using a scanning electron microscope (“RS6000” from Hitachi High-Technologies Corporation). Observation and measurement of bridge defects and disconnection defects. The bridge defect suppression property and the disconnection defect suppression property can be evaluated as “good” when the number of defects is less than 100 per wafer, and as “bad” when the number of defects is 100 or more.

  From the results of Table 6, according to the negative resist pattern forming method of the example, the lithography characteristics such as DOF, CDU, LWR performance, etc. are improved while maintaining a good receding contact angle on the surface of the upper layer film. It was shown that it is possible to form a resist pattern that is excellent in suppression and disconnection defect suppression. In particular, Example 7 has a receding contact angle in combination with a resist film composed of a radiation-sensitive resin composition containing fluorine atoms, even though the upper layer film-forming composition does not contain fluorine atoms. Good results were obtained for DOF, CDU, LWR, and the like, and development defect suppression was excellent. In Examples 1 to 4, the receding contact angle was good despite the small mass content of fluorine atoms in the composition for forming an upper layer film. Therefore, according to the negative resist pattern forming method, it was confirmed that the good water repellency required for immersion exposure can be maintained even if the content of fluorine atoms in the upper layer film that causes bridge defects is reduced. It was. On the other hand, in a negative resist pattern forming method in which an upper layer film of a comparative example is not formed, or in a negative resist pattern forming method in which a resist film is not formed using a radiation-sensitive resin composition containing a polymer containing fluorine atoms At least one of receding contact angle, DOF, CDU, LWR, and development defect suppression was poor.

  According to the negative resist pattern forming method of the present invention, a negative resist pattern formation that can form a resist pattern having excellent lithography characteristics and few development defects while maintaining good water repellency on the surface of the upper layer film. can do. Therefore, the negative resist pattern forming method can be suitably used for pattern formation in the field of semiconductor devices and the like that will require further miniaturization and higher quality in the future.

Claims (17)

Forming a resist film using the radiation-sensitive resin composition;
A step of forming an upper layer film on one surface of the resist film with the upper layer film forming composition;
A step of immersion exposure of the resist film on which the upper layer film is formed; and a step of developing the resist film subjected to the immersion exposure with a developer containing an organic solvent,
The negative resist pattern formation method in which the said radiation sensitive resin composition contains the [A] polymer containing a fluorine atom, the [B] polymer which has an acid dissociable group, and the [C] radiation sensitive acid generator. The composition for forming an upper layer film is
[J] a polymer;
[P] a solvent and
Satisfy at least one selected from the group consisting of (i) and (ii) below,
(I) The composition for forming an upper layer film further contains a [K] acid diffusion inhibiting compound. (Ii) The [J] polymer contains a structural unit (VI) having an acid diffusion inhibiting group. The diffusion inhibiting compound includes a compound represented by the following formula (1), a compound represented by the following formula (2), a compound represented by the following formula (3), or a combination thereof,
The acid diffusion inhibiting group is a group represented by the following formula (1 ′), a group represented by the following formula (2′-1), a group represented by the following formula (2′-2), the following formula ( The negative resist pattern forming method according to claim 1, comprising a group represented by 3 ′) or a combination thereof.

(In the formula (1), R ^A and R ^B are a hydrogen atom, a monovalent organic group having 1 to 20 carbon atoms, or are configured together with a nitrogen atom to which these groups are combined and bonded to each other. An aliphatic heterocyclic structure having 3 to 20 ring members is represented, and R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms.
In the formula (2), X ⁺ is a monovalent onium cation. Y ⁻ is a monovalent weak acid anion.
In formula (3), R ¹⁸ , R ¹⁹ and R ²⁰ are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, an aryl group or an aralkyl group.
In formula (1 ′), E represents a single bond or a divalent organic group having 1 to 20 carbon atoms. R ^J is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ^J and E may represent an aliphatic heterocyclic structure having 3 to 20 ring members that is formed together with the nitrogen atom to which they are bonded. R ¹ ′ is a monovalent hydrocarbon group having 1 to 20 carbon atoms.
In formula (2′-1), X ′ ⁺ is a monovalent group containing a monovalent onium cation. Y ^'- is a monovalent weak acid anions.
In formula (2′-2), Y ″ ^— is a monovalent group containing a monovalent weak acid anion. X ″ ⁺ is a monovalent onium cation.
In formula (3 ′), E ′ is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ²⁸ and R ²⁹ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ²⁸ , R ^29, and E ′ may represent an aliphatic heterocyclic structure having 3 to 20 ring members that is formed together with the nitrogen atom to which any two of these groups are combined with each other. )   The negative resist pattern forming method according to claim 2, wherein the [K] acid diffusion inhibiting compound is a compound represented by the formula (1).   The [K] acid diffusion inhibiting compound is a compound represented by the above formula (2), wherein the monovalent weak acid anion is weaker than an acid generated from the [C] radiation sensitive acid generator. The negative resist pattern forming method according to claim 2.   The negative resist pattern forming method according to claim 2, wherein the [K] acid diffusion inhibiting compound is a compound represented by the formula (3).   The acid diffusion inhibiting group is a compound represented by the formula (2′-1) or the formula (2′-2), and the monovalent weak acid anion is the [C] radiation-sensitive acid generator. The negative resist pattern forming method according to claim 2, wherein the acid is weaker than an acid generated from the resist.   The negative resist pattern forming method according to any one of claims 2 to 6, wherein the [J] polymer in the composition for forming an upper layer film has a structural unit (IV) containing a hydrocarbon structure.   The negative resist pattern forming method according to claim 7, wherein the hydrocarbon structure is an alicyclic structure.   The negative resist pattern forming method according to claim 7 or 8, wherein the content of the structural unit (IV) with respect to the [J] polymer in the composition for forming an upper layer film is 50 mol% or more.   The negative resist pattern forming method according to claim 7 or 8, wherein the content of the structural unit (IV) relative to the [J] polymer in the composition for forming an upper layer film is 70 mol% or more.   The negative resist pattern forming method according to any one of claims 1 to 10, wherein a content of fluorine atoms with respect to a total solid content of the composition for forming an upper layer film is 2% by mass or more and 30% by mass or less. .   The negative resist pattern forming method according to any one of claims 2 to 11, wherein the solvent in the composition for forming an upper layer film contains an alcohol solvent.   The negative resist pattern forming method according to any one of claims 2 to 11, wherein the solvent in the composition for forming an upper layer film contains an ether solvent.   The negative resist pattern forming method according to any one of claims 2 to 11, wherein the solvent in the composition for forming an upper layer film includes an alcohol solvent and an ether solvent.   The negative resist pattern forming method according to claim 12, wherein the content of the alcohol-based solvent with respect to the solvent in the composition for forming an upper layer film is 70% by mass or more.   The negative resist pattern forming method according to claim 13, wherein the content of the ether solvent with respect to the solvent in the composition for forming an upper layer film is 70% by mass or more.   The negative resist pattern forming method according to claim 14, wherein a total content of the alcohol solvent and the ether solvent with respect to the solvent in the composition for forming an upper layer film is 70% by mass or more.