JP2010210751A - Coating agent for resist pattern and method for forming pattern by using the agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating agent for a resist pattern, which is excellent in performance (curing performance) of insolubilizing and curing a resist pattern, and allows an insoluble resist pattern which is sufficiently stable against a subsequent exposure process, a developing solution and a positive radiation-sensitive resin composition. <P>SOLUTION: The coating agent for a resist pattern contains: (I) a resin having a structural unit derived from at least one monomer of hydroxyacrylanilide and hydroxymethacrylanilide; and (II) a radical generator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resist pattern coating agent and a method for forming a fine resist pattern using the same.

  In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, lithography technology capable of microfabrication at a level of 0.10 μm or less is required. In the conventional lithography process, near ultraviolet rays such as i-line are generally used as radiation, and it is said that fine processing at the subquarter micron level is extremely difficult with this near ultraviolet rays. Therefore, in order to enable fine processing at a level of 0.10 μm or less, use of radiation having a shorter wavelength is being studied. Examples of such short-wavelength radiation include an emission line spectrum of a mercury lamp, far ultraviolet rays typified by an excimer laser, X-rays, and electron beams. Among these, KrF excimer laser (wavelength 248 nm) and ArF excimer laser (wavelength 193 nm) are attracting attention.

  As a resist suitable for irradiation with such an excimer laser, a component having an acid dissociable functional group and a component that generates an acid upon irradiation with radiation (hereinafter also referred to as “exposure”) (hereinafter referred to as “acid generator”) Many resists using the chemical amplification effect (hereinafter also referred to as “chemically amplified resist”) have been proposed. As the chemically amplified resist, for example, a resist containing a resin having a tert-butyl ester group of carboxylic acid or a tert-butyl carbonate group of phenol and an acid generator has been proposed (see, for example, Patent Document 1). ). In this resist, the tert-butyl ester group or tert-butyl carbonate group present in the resin is dissociated by the action of an acid generated by exposure, and the resin has an acidic group composed of a carboxyl group or a phenolic hydroxyl group. As a result, the phenomenon that the exposed region of the resist film becomes readily soluble in an alkali developer is utilized.

  In such a lithography process, further fine pattern formation (for example, a fine resist pattern having a line width of about 45 nm) will be required in the future. In order to achieve such a finer pattern formation, it is conceivable to shorten the light source wavelength of the exposure apparatus and increase the numerical aperture (NA) of the lens as described above. However, in order to shorten the light source wavelength, a new expensive exposure apparatus is required. Further, when the lens has a high NA, the resolution and the depth of focus are in a trade-off relationship. Therefore, there is a problem that the depth of focus decreases even if the resolution is increased.

  In recent years, a liquid immersion lithography (liquid immersion lithography) method has been disclosed as a lithography technique that can solve such problems (for example, see Patent Document 2). In this method, at the time of exposure, a liquid high refractive index medium (immersion exposure liquid) such as pure water or fluorine-based inert liquid having a predetermined thickness is formed on at least the resist film between the lens and the resist film on the substrate. It is a method of interposing. According to this method, a light source having the same exposure wavelength is used by replacing the exposure optical path space, which has conventionally been an inert gas such as air or nitrogen, with a liquid having a higher refractive index (n), such as pure water. However, as in the case of using a light source with a shorter wavelength or the case of using a high NA lens, high resolution is achieved and there is no reduction in the depth of focus. That is, according to this method, using a lens mounted on an existing apparatus, it is possible to realize a resist pattern that is low in cost, excellent in resolution, and excellent in depth of focus. It is being put to practical use.

  However, it is said that the above-described advancement of the exposure technique is limited to 45 nmhp, and technical development for the 32 nmhp generation that requires further fine processing is being carried out. In recent years, in accordance with the demand for higher complexity and higher density of such devices, a technique for patterning 32 nm LS by overlapping half-cycles of sparse line patterns or isolated trench patterns such as double patterning or double exposure has been proposed. (For example, refer nonpatent literature 1).

  In Non-Patent Document 1, a 32 nm line having a pitch of 1: 3 is formed and then processed by etching, and a 32 nm line having a pitch of 1: 3 is similarly formed at a position shifted by a half period from the first resist pattern. It is disclosed that it is formed and processed again by etching to finally form a 32 nm line with a 1: 1 pitch.

Japanese Patent Laid-Open No. 5-232704 JP-A-10-303114

SPIE 2006 Vol. 6153 6153K

  However, although there are proposals for several processes as described above, no proposals for more specific and practical methods and materials have been made yet.

  The present invention has been made in view of such problems of the prior art, and the problem is that the resist pattern is insolubilized and cured (curing performance), and has a subsequent exposure process. An object of the present invention is to provide a resist pattern coating agent capable of forming an insolubilized resist pattern that is sufficiently stable with respect to a developer and a positive-type radiation-sensitive resin composition.

  Another object of the present invention is to provide a resist pattern forming method capable of easily and efficiently forming a finer resist pattern.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have generated (I) a resin containing a structural unit derived from at least one monomer of hydroxyacrylanilide and hydroxymethacrylanilide, and generates radicals (II ) It was found that the above-mentioned problems can be achieved by blending with a radical generator, and the present invention has been completed.

  That is, according to the present invention, the following resist pattern coating agent and resist pattern forming method are provided.

  [1] A resist pattern coating agent comprising (I) a resin containing a structural unit derived from at least one monomer of hydroxyacrylanilide and hydroxymethacrylanilide, and (II) a radical generator.

  [2] The resist pattern coating agent according to [1], wherein the radical generator (II) is a compound containing a repeating unit represented by the following general formula (1).

In the general formula (1), A represents an alkyl group of 1 to 20, a saturated cyclic group, or an aromatic ring, and R ¹ , R ² , and R ³ are each independently a hydrogen atom or a carbon number A linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxyl group having 1 to 8 carbon atoms, or a hydroxyl group is shown.

  [3] (1) A first resist layer formed on a substrate is selectively exposed using the first positive radiation-sensitive resin composition and then developed to form a first resist pattern. And (2) applying the resist pattern coating agent according to [1] or [2] on the first resist pattern, baking or UV curing, washing, and A step (2) in which one resist pattern is an insolubilized resist pattern insoluble in a developer and a second positive radiation sensitive resin composition; and (3) the second positive radiation sensitive resin composition. Forming a second resist layer on the insolubilized resist pattern using an object, and selectively exposing the formed second resist layer; and (4) developing the second resist And (4) forming a pattern. Resist pattern forming method.

  The resist pattern coating agent of the present invention is excellent in performance (curing performance) for insolubilizing and curing a resist pattern, and is sufficiently insolubilized sufficiently for subsequent exposure processing, developer, and positive-type radiation-sensitive resin composition. There is an effect that a resist pattern can be formed.

  According to the resist pattern forming method of the present invention, a finer resist pattern can be easily and efficiently formed.

It is sectional drawing which shows an example of a 1st resist pattern typically. It is sectional drawing which shows an example of an insolubilized resist pattern typically. It is a top view which shows an example of an insolubilized resist pattern typically. It is sectional drawing which shows typically an example of the state which formed the 2nd resist layer on the insolubilization resist pattern. It is a top view which shows typically an example of the state which formed the line part of the 2nd resist pattern in the space part of the insolubilized resist pattern. It is a top view which shows typically the other example of the state which formed the line part of the 2nd resist pattern in the space part of the insolubilized resist pattern. It is a top view which shows typically an example of the state which formed the line part of the 2nd resist pattern on the line part of the insolubilized resist pattern. It is a side view which shows typically an example of the state which formed the line part of the 2nd resist pattern on the line part of the insolubilized resist pattern.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

1. Resist pattern coating agent:
The resist pattern coating agent of the present invention comprises (I) a resin containing a structural unit derived from at least one monomer of hydroxyacrylanilide and hydroxymethacrylanilide, and (II) a radical generator. is there. By blending these two components ((I) resin and (II) radical generator), insolubilization is excellent in curing performance and sufficiently stable for exposure processing, developer, and positive radiation sensitive resin composition. A resist pattern can be formed. The details will be described below.

((I) Resin)
(I) The resin contains a structural unit derived from at least one monomer of hydroxyacrylanilide and hydroxymethacrylanilide. Hereinafter, “hydroxyacrylanilide” and “hydroxymethacrylanilide” are also collectively referred to as “hydroxy (meth) acrylanilide”.

(Hydroxy (meth) acrylanilide)
Hydroxy (meth) acrylanilide is, for example, a compound that can be represented by the following general formula (2).

In the general formula (2), R ⁴ independently represents a hydrogen atom or a methyl group, and R ⁵ represents a single bond or a linear, branched or cyclic divalent hydrocarbon group. Show.

Among the groups represented by R ⁵ in the general formula (2), specific examples of the linear, branched or cyclic divalent hydrocarbon group include a methylene group, an ethylene group, and a propylene group (1,3 -Propylene group, 1,2-propylene group), tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group Group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonadecamethylene group, icosalen group, 1-methyl-1,3-propylene group, 2-methyl- 1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1,4-butyl Saturated chain hydrocarbon groups such as a thylene group, an ethylidene group, a 1-propylidene group and a 2-propylidene group; a cyclobutylene group such as a 1,3-cyclobutylene group and a cyclopentylene group such as a 1,3-cyclopentylene group A monocyclic hydrocarbon ring such as a cycloalkylene group having 3 to 10 carbon atoms such as a cyclohexylene group such as a 1,4-cyclohexylene group and a cyclooctylene group such as a 1,5-cyclooctylene group Groups: 2-4 cyclic groups including norbornylene groups such as 1,4-norbornylene group and 2,5-norbornylene group, adamantylene groups such as 1,5-adamantylene group and 2,6-adamantylene group Examples thereof include a bridged cyclic hydrocarbon ring group such as a hydrocarbon ring group having 4 to 30 carbon atoms.

  (I) The resin can be produced by polymerizing a monomer component containing at least one of hydroxyacrylanilide and hydroxymethacrylanilide. The proportion of hydroxy (meth) acrylanilide contained in the monomer component is usually 30 to 95 mol%, preferably 40 to 90 mol%, relative to 100 mol% of the monomer component.

  (I) The monomer component used for producing the resin includes at least one of the following monomers (i) to (vii) as a monomer other than the above-mentioned hydroxy (meth) acrylanilide Is preferably further included.

(Monomer (i))
The monomer (i) is a compound represented by the following general formula (i).

In the general formula (i), R ⁶ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, A represents a methylene group, an ethylene group, or a propylene group, and R ⁷ represents the following formula (i-1) or The group represented by (ii-2) is shown.

  Specific examples of the monomer (i) include 2-[(3,5-dimethylpyrazolyl) carbonylamino] ethyl methacrylate (trade name “MOI-BP”, manufactured by Showa Denko KK), 2- [0- (1 -Methylpropylideneamino) carbonylamino] ethyl methacrylate (trade name “MOI-BM”, manufactured by Showa Denko KK).

(Monomer (ii))
The monomer (ii) is a compound represented by the following general formula (ii).

In the general formula (ii), R ⁸ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R ⁹ represents a methylene group or an alkylene group having 2 to 6 carbon atoms, and R ¹⁰ represents a hydrogen atom, methyl Group represents an ethyl group, and n represents 0 or 1. Specific examples of the monomer (ii) include glycidyl methacrylate, glycidyl acrylate, (1-ethyl-1-oxetanyl) methyl methacrylate (trade name “OXMA”, manufactured by Ube Industries).

  The total proportion of monomer (i) and monomer (ii) contained in the monomer component is usually 5 to 60 mol%, preferably 5 to 50 mol%, relative to 100 mol% of the monomer component. More preferably, it is 5 to 40 mol%.

(Monomer (iii))
The monomer (iii) is a compound represented by the following general formula (iii), that is, a styrene derivative.

In the general formula (iii), R ¹¹ represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxyl group having 1 to 8 carbon atoms. This monomer (iii) is preferably a monomer having a specific functional group that can be converted into a phenolic hydroxyl group after copolymerization (hereinafter referred to as “specific functional group-containing monomer”). Specific examples of the specific functional group-containing monomer include p-acetoxystyrene, α-methyl-p-acetoxystyrene, p-benzyloxystyrene, p-tert-butoxystyrene, p-tert-butoxycarbonyloxystyrene, Examples include p-tert-butyldimethylsiloxystyrene. After copolymerizing a monomer component containing a specific functional group-containing monomer, the specific functional group can be easily converted into a phenolic hydroxyl group by appropriate treatment such as hydrolysis with hydrochloric acid or the like. be able to.

  The proportion of monomer (iii) contained in the monomer component is usually 5 to 65 mol%, preferably 10 to 50 mol%, relative to 100 mol% of the monomer component.

(Monomer (iv))
Monomer (iv) is a monomer having an alcoholic hydroxyl group. Specific examples of the monomer (iv) include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, glycerol mono Examples thereof include hydroxyalkyl (meth) acrylates such as methacrylate. Of these, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate are preferable. These monomers (iv) can be used individually by 1 type or in combination of 2 or more types.

  The proportion of monomer (iv) contained in the monomer component is usually 5 to 65 mol%, preferably 10 to 60 mol%, relative to 100 mol% of the monomer component.

(Monomer (v))
The monomer (v) is a monomer having a hydroxyl group derived from an organic acid such as carboxylic acid. Specific examples of the monomer (v) include acrylic acid, methacrylic acid, crotonic acid, 2-succinoloylethyl (meth) acrylate, 2-malenoylethyl (meth) acrylate, and 2-hexahydrophthaloylethyl. Monocarboxylic acids such as (meth) acrylate, ω-carboxy-polycaprolactone monoacrylate, monohydroxyethyl phthalate, acrylic acid dimer, 2-hydroxy-3-phenoxypropyl acrylate, t-butoxy methacrylate, t-butyl acrylate; Examples thereof include (meth) acrylic acid derivatives having a carboxyl group, including dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid. Of these, acrylic acid, methacrylic acid, and 2-hexahydrophthaloylethyl methacrylate are preferable. These monomers (v) can be used alone or in combination of two or more.

  The proportion of the monomer (v) contained in the monomer component is usually 5 to 65 mol%, preferably 10 to 60 mol%, relative to 100 mol% of the monomer component.

(Monomer (vi))
The monomer (vi) is a monomer having a phenolic hydroxyl group. However, the concept of monomer (6) does not include hydroxy (meth) acrylanilide. Specific examples of the monomer (vi) include p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, α-methyl-p-hydroxystyrene, α-methyl-m-hydroxystyrene, α-methyl-o. -Hydroxystyrene, 2-allylphenol, 4-allylphenol, 2-allyl-6-methylphenol, 2-allyl-6-methoxyphenol, 4-allyl-2-methoxyphenol, 4-allyl-2,6-dimethoxy Phenol, 4-allyloxy-2-hydroxybenzophenone, etc. can be mentioned. Of these, p-hydroxystyrene and α-methyl-p-hydroxystyrene are preferable.

  The proportion of the monomer (vi) contained in the monomer component is usually 5 to 65 mol%, preferably 5 to 50 mol%, more preferably 5 to 45 mol% with respect to 100 mol% of the monomer component. is there.

  When the ratio of each of the above-mentioned monomers (iv) to (vi) contained in the monomer component is too small, the number of reaction sites with the crosslinking component described later is too small, so that the resist pattern shrinks excessively. It tends to occur easily. On the other hand, if the proportion of each of the above-mentioned monomers (iv) to (vi) contained in the monomer component is too large, the resist pattern may be buried due to swelling during development. That is, the line width of the insolubilized resist pattern formed using the resist pattern coating agent when the proportion of each of the monomers (iv) to (vi) contained in the monomer component is outside the above range. It may be difficult to control the variation.

(Monomer (vii))
Specific examples of the monomer (vii) include (meth) acrylic acid aryl esters, dicarboxylic acid diesters, nitrile group-containing polymerizable compounds, amide bond-containing polymerizable compounds, vinyls, allyls, and chlorine-containing polymerizable compounds. And conjugated diolefins. More specifically, dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate and diethyl itaconate; aryl (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate; t-butyl (meth) (Meth) acrylic acid esters such as acrylate, 4,4,4-trifluoro-3-hydroxy-1-methyl-3-trifluoromethyl-1-butyl (meth) acrylate; nitrile groups such as acrylonitrile and methacrylonitrile -Containing polymerizable compounds; amide bond-containing polymerizable compounds such as acrylamide and methacrylamide; fatty acid vinyls such as vinyl acetate; chlorine-containing polymerizable compounds such as vinyl chloride and vinylidene chloride; 1,3-butadiene, isoprene, 1,4 -Conjugated diolefins such as dimethylbutadiene It can gel. These monomers (vii) can be used individually by 1 type or in combination of 2 or more types.

  In addition, as a suitable example of a monomer (vii), the compound etc. which are represented with the following general formula (vii) can be mentioned.

In the general formula (vii), R ^{12 to} R ¹⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a hydroxymethyl group, a trifluoromethyl group, or a phenyl group, and R ¹⁵ represents Represents a monovalent organic group, R ¹⁶ represents a single bond or a divalent organic group having 1 to 20 carbon atoms, and B represents a single bond, an oxygen atom, a carbonyl group, a carbonyloxy group, or an oxycarbonyl. Indicates a group.

Among the groups represented by R ^{12 to} R ¹⁴ in the general formula (vii), specific examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Group, heptyl group, octyl group, nonyl group, decyl group and the like. In the general formula (vii), R ¹² and R ¹³ are preferably hydrogen atoms, and R ¹⁴ is preferably a hydrogen atom or a methyl group.

In the general formula (vii), R ¹⁵ is preferably a monovalent organic group containing a fluorine atom, more preferably a fluoroalkyl group having 1 to 20 carbon atoms, and fluoro having 1 to 4 carbon atoms. Particularly preferred is an alkyl group. Specific examples of the “fluoroalkyl group having 1 to 20 carbon atoms” include difluoromethyl group, perfluoromethyl group, 1,1-difluoroethyl group, 2,2-difluoroethyl group, 2,2,2-trifluoro. Ethyl group, perfluoroethyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl ) -1,2,2,2-tetrafluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexafluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, 2- (P Fluoropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,4,5, 5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group, 1, 1,2,2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl Group, perfluoropentylmethyl group, perfluorohexyl group, 2- (perfluoropentyl) ethyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluoroheptyl Group, perfluorohexylmethyl group, perfluorohexene Tyl group, 2- (perfluorohexyl) ethyl group, 1,1,2,2,3,3,4,4,5,5,6,6,7,7-tetradecafluorooctyl group, perfluoroheptyl Methyl group, perfluorooctyl group, 2- (perfluoroheptyl) ethyl group, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8- Hexadecafluorononyl group, perfluorooctylmethyl group, perfluorononyl group, 2- (perfluorooctyl) ethyl group, 1,1,2,2,3,3,4,4,5,5,6,6 , 7, 7, 8, 8, 9, 9-octadecafluorodecyl group, perfluorononylmethyl group, perfluorodecyl group, and the like. Among these, if the fluoroalkyl group has too many carbon atoms, the solubility in an alkaline aqueous solution tends to be low, and therefore, a perfluoromethyl group, a perfluoroethyl group, and a perfluoropropyl group are preferable.

In the general formula (vii), among the groups represented by R ¹⁶ , specific examples of the divalent organic group having 1 to 20 carbon atoms include a methylene group, an ethylene group, a propylene group (1,3-propylene group, 1,2-propylene group), tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradeca Methylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonadecamethylene group, icosalen group, 1-methyl-1,3-propylene group, 2-methyl-1,3- Propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene Group, methylidene group, ethylidene group, 1-propylidene group, 2-propylidene group and other saturated chain hydrocarbon groups; 1,3-cyclobutylene group and other cyclobutylene groups and 1,3-cyclopentylene group and other cyclohexane groups Monocyclic such as cycloalkylene groups having 3 to 10 carbon atoms such as pentylene groups, cyclohexylene groups such as 1,4-cyclohexylene groups, and cyclooctylene groups such as 1,5-cyclooctylene groups Hydrocarbon ring groups; norbornylene groups such as 1,4-norbornylene group and 2,5-norbornylene group; adamantylene groups such as 1,5-adamantylene group and 2,6-adamantylene group; Examples thereof include a bridged cyclic hydrocarbon ring group such as a 4-cyclic hydrocarbon ring group having 4 to 20 carbon atoms.

  Preferable examples of the compound represented by the general formula (vii) (monomer (vii)) include 2-(((trifluoromethyl) sulfonyl) amino) ethyl-1-methacrylate, 2-(((tri Examples include fluoromethyl) sulfonyl) amino) ethyl-1-acrylate, compounds represented by the following formulas (vii-1) to (vii-6), and the like.

  The proportion of the monomer (vii) contained in the monomer component is usually 1 to 50 mol%, preferably 2 to 30 mol%, more preferably 2 to 20 mol% with respect to 100 mol% of the monomer component. is there.

((I) Resin preparation method)
(I) Resin uses, for example, radical polymerization initiators such as hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds, etc., in the presence of a chain transfer agent added as necessary. It can be prepared by polymerizing the monomer component in a suitable solvent.

  Specific examples of the solvent used in the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, Cycloalkanes such as norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; halogenated hydrocarbons such as chlorobutane, bromohexane, dichloroethane, hexamethylene dibromide, chlorobenzene; ethyl acetate, n acetate -Saturated carboxylic acid esters such as butyl, i-butyl acetate, methyl propionate, propylene glycol monomethyl ether acetate; alkyl lactones such as γ-butyrolactone; ethers such as tetrahydrofuran, dimethoxyethane, diethoxyethane; 2 Alkyl ketones such as butanone, 2-heptanone and methyl isobutyl ketone; cycloalkyl ketones such as cyclohexanone; alcohols such as 2-propanol, 1-butanol, 4-methyl-2-pentanol and propylene glycol monomethyl ether Can be mentioned. These solvents can be used alone or in combination of two or more.

  The temperature of the polymerization reaction is usually 40 to 120 ° C, preferably 50 to 100 ° C. The polymerization reaction time is usually 1 to 48 hours, preferably 1 to 24 hours.

  (I) The resin preferably has a low content of impurities such as halogen and metal and high purity. Moreover, it is more preferable that the content ratio of the monomer component and oligomer component (I) remaining in the tree is not more than a predetermined value (for example, 0.1% by mass or less by HPLC analysis). Use of a resist pattern coating agent containing a high-purity (I) resin is preferable because process stability is improved and the resist pattern shape can be further refined.

  (I) As a method for removing impurities such as metals contained in the resin, for example, (1) a method of adsorbing metals in a polymerization solution using a zeta potential filter, (2) an acidic aqueous solution of oxalic acid, sulfonic acid, etc. And a method of removing the metal in a chelate state by washing the polymerization solution. Moreover, (I) As a method of making the content rate of the monomer component and oligomer component which remain | survive in resin below a predetermined value, for example, (1) The monomer component which remains by combining water washing and a suitable solvent And liquid-liquid extraction methods for removing oligomer components, (2) purification methods such as ultrafiltration for extracting and removing only components below a specific molecular weight, and (3) dropping the polymerization solution into a poor solvent. The resin having a hydroxyl group is coagulated in a poor solvent, and a reprecipitation method for removing the remaining monomer components, (4) (I) the roughly purified resin product is washed with a slurry poor solvent, etc. Examples thereof include a purification method in a solid state. It is also preferable to implement a combination of a plurality of the above methods as appropriate.

  (I) The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of the resin is usually 1,000 to 500,000, preferably 1,000 to 50,000, more preferably 1. , 20,000 to 20,000. (I) If the weight average molecular weight (Mw) of the resin exceeds 500,000, it tends to be difficult to remove with a developer after thermosetting. On the other hand, when the weight average molecular weight (Mw) of the (I) resin is less than 1,000, it tends to be difficult to form a uniform coating film after coating.

((II) radical generator)
(II) A radical generator is a compound that generates radicals by heating or the like. This (II) radical generator is a compound which generates radicals preferably at 50 to 160 ° C, more preferably at 50 to 140 ° C. By containing this (II) radical generator, radicals can be generated by heat, and the curing reaction of the crosslinking agent can be promoted.

  The amount of the (II) radical generator contained in the resist pattern coating agent is preferably 1 to 10 parts by mass, more preferably 0.5 to 6 parts by mass with respect to 100 parts by mass of the resin. . (II) When the content of the radical generator is less than 0.5 parts by mass, the number of reaction points decreases, and curing may not proceed efficiently. On the other hand, when the content of the radical generator (II) is more than 10 parts by mass, curing is insufficient and pattern damage tends to increase.

  (II) The radical generator is preferably a compound containing a repeating unit represented by the following general formula (1).

In the general formula (1), A represents an alkyl group of 1 to 20, a saturated cyclic group, or an aromatic ring, and R ¹ , R ² , and R ³ are each independently a hydrogen atom or a carbon number A linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxyl group having 1 to 8 carbon atoms, or a hydroxyl group is shown. In addition, it is preferable that the repeating number (n) of the repeating unit represented by the said General formula (1) contained in (II) radical generator is 1-10, and it is still more preferable that it is 2-9. 3 to 8 is particularly preferable.

  Preferred examples of the repeating unit represented by the general formula (1) in which “A” in the general formula (1) is an aromatic ring include the following formulas (1-1) to (1-18). ) Can be mentioned. In the following formulas (1-1) to (1-18), n is preferably an integer of 1 to 10, more preferably an integer of 2 to 9, and an integer of 3 to 8. Is particularly preferred. However, the repeating unit represented by the general formula (1) is not limited to the preferred examples shown below.

(Alcohol solvent)
The resist pattern coating agent of the present invention usually contains an alcohol solvent. This alcohol solvent is a solvent containing alcohol, and is preferably a solvent substantially consisting of alcohol. The alcohol solvent is generally capable of sufficiently dissolving (I) a resin, (II) a radical generator, and components (such as a crosslinking component) blended as necessary, and the first positive radiation sensitive. It is a solvent that does not substantially dissolve the first resist pattern formed using the conductive resin composition.

  The amount of the alcohol solvent used is preferably 80% by mass or more, and more preferably 90% by mass or more, when the total amount of organic solvents contained in the resist pattern coating agent is 100% by mass. In addition, although there is no limitation in particular about the upper limit of the usage-amount of alcohol solvent, it is especially preferable that it is 100 mass%.

  The water content of the alcohol solvent is preferably 10% by mass or less, and more preferably 3% by mass or less. When the water content of the alcohol solvent is more than 10% by mass, the solubility of (I) resin tends to decrease. The alcohol solvent is preferably a non-aqueous solvent containing alcohol, and more preferably an anhydrous alcohol solvent substantially free of water.

  The alcohol contained in the alcohol solvent is preferably a monohydric alcohol having 1 to 8 carbon atoms. Specific examples of such alcohols include 1-propanol, isopropyl alcohol, 1-butanol, 2-butanol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1 -Butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2 -Methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2- Pentanol, 1-heptanol, 2-heptanol, 2-methyl-2-heptanol, 2-methyl-3-heptanol It can be mentioned. Of these, 1-butanol, 2-butanol, and 4-methyl-2-pentanol are preferable. These alcohols can be used singly or in combination of two or more.

  In order to adjust the applicability when the resist pattern coating agent is applied on the first resist pattern, the alcohol solvent may contain other solvents other than alcohol. As the “other solvent”, a solvent that does not erode the first resist pattern and exhibits an effect of improving the applicability of the resist pattern coating agent can be suitably used.

  Specific examples of “other solvents” include 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 Alkyl ethers of polyhydric alcohols such as dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether Alkyl ether acetates of polyhydric alcohols such as teracetate and propylene glycol monomethyl ether acetate; aromatic hydrocarbons such as toluene and xylene; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2- Ketones such as pentanone and diacetone alcohol; ethyl acetate, butyl acetate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, hydroxy Ethyl acetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate An ester such as ethyl acetate or butyl acetate; water, and the like. Of these, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ketones, esters, and water are preferred. These “other solvents” can be used singly or in combination of two or more.

  When the “other solvent” is contained in the alcohol solvent, the content ratio of the “other solvent” is usually 30% by mass or less, preferably 20% by mass or less in 100% by mass of the alcohol solvent. If the content ratio of “other solvent” is more than 30% by mass, the first resist pattern may be eroded, causing problems such as intermixing with the resist pattern coating agent. One resist pattern may be buried. When the “other solvent” is water, the content of water is preferably 10% by mass or less in 100% by mass of the alcohol solvent.

(Crosslinking component)
The resist pattern coating agent of the present invention preferably contains a crosslinking component as an optional component. A crosslinking component is a component which reacts with (I) resin by the effect | action of an acid, or reacts with crosslinking components, and shows the effect | action which hardens (I) resin.

  When making a resist pattern coating agent contain a crosslinking component, it is preferable that it is 1-100 mass parts with respect to 100 mass parts of (I) resin, and it is further 5-70 mass parts. preferable. When the content of the crosslinking component is less than 1 part by mass, the curing becomes insufficient and the first resist pattern tends not to shrink. On the other hand, if it exceeds 100 parts by mass, curing may proceed excessively and the first resist pattern may be buried.

  The total ratio of (I) resin and crosslinking component contained in the resist pattern coating agent is preferably 0.1 to 30% by mass, and 1 to 20% by mass in 100% by mass of the resist pattern coating agent. More preferably it is. (I) If the total content of the resin and the crosslinking component is less than 0.1% by mass, the coating film may become too thin, and film breakage may occur at the pattern edge portion. On the other hand, if it exceeds 30% by mass, the viscosity of the resist pattern coating agent becomes too high, and it may be difficult to embed the resist pattern coating agent in a fine pattern.

  Specific examples of the crosslinking component include a compound having a group represented by the following general formula (3) (hereinafter also referred to as “crosslinking component (1)”), a compound having two or more cyclic ethers as a reactive group (hereinafter referred to as “reactive group”). , Also referred to as “crosslinking component (2)”. The crosslinking component (1) and the crosslinking component (2) may be used alone or in combination of two kinds.

In the general formula (3), R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom or a group represented by the following general formula (4). However, at least one of R ¹⁷ and R ¹⁸ is a group represented by the following general formula (4).

In the general formula ^{(4), R 19} and ^{R 20} represents independently of one another, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxyalkyl group having 1 to 6 carbon atoms. R ¹⁹ and R ²⁰ may be bonded to each other to form a ring having 2 to 10 carbon atoms. R ²¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

  Specific examples of the crosslinking component (1) include compounds having a functional group such as an imino group, a methylol group, or a methoxymethyl group in the molecule. More specifically, all or a part of active methylol groups such as (poly) methylolated melamine, (poly) methylolated glycoluril, (poly) methylolated benzoguanamine, and (poly) methylolated urea are alkylated. Examples thereof include nitrogen-containing compounds as alkyl ethers.

  Specific examples of the “alkyl group” when alkylating all or part of the active methylol group include a methyl group, an ethyl group, a butyl group, or a group obtained by mixing these. Further, the nitrogen-containing compound may contain an oligomer component partially self-condensed. Specific examples of such nitrogen-containing compounds include hexamethoxymethylated melamine, hexabutoxymethylated melamine, tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril and the like.

As the commercially available crosslinking component (1), the following trade names are as follows: Cymel 300, 301, 303, 350, 232, 235, 236, 238, 266, 267, 285. 1123, 1123-10, 1170, 370, 771, 272, 1172, 325, 327, 703, 712, 254, 253, 212, 1128, 701 202, 207 (manufactured by Nippon Cytec Co., Ltd.), Nicarak MW-30M, 30, 22, 24X, Nicarak MS-21, 11, 001, Nicarax MX-002, 730, 750 708, 706, 042, 035, 45, 410, 302, 202, Nicarak SM-651, 652, 653, 551, 45 Nicalack SB-401, 355, 303, 301, 255, 203, 201, Nicalack BX-4000, 37, 55H, Nicalack BL-60 (manufactured by Sanwa Chemical Co., Ltd.), etc. Can be mentioned. Among them, Cymel 325, 327, 703, 712, 254, 253, 212, 1128, which corresponds to the compound in which R ¹⁹ or R ²⁰ is a hydrogen atom in the general formula (4), 701, 202 and 207 are preferable. The crosslinking component (1) described above can be used singly or in combination of two or more.

  Specific examples of the crosslinking component (2) include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4- Epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4'-epoxy-6'-methylcyclohexanecarboxylate, methylene bis (3,4-epoxycyclohexane), di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylene bis (3,4-epoxycyclohexanecarboxylate) , Ε-caprolactone modification 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, trimethylcaprolactone modified 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, β-methyl-δ-valerolactone modified An epoxycyclohexyl group-containing compound such as 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate;

  Bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, Hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol Diglycidyl ether, polypropylene glycol diglycidyl ethers;

  Polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin; diglycidyl esters of aliphatic long-chain dibasic acids; aliphatic Monoglycidyl ethers of higher alcohols; monoglycidyl ethers of polyether alcohols; glycidyl esters of higher fatty acids;

  3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)) bis- (3-ethyloxetane), 1 , 4-bis ((3-ethyl-3-oxetanylmethoxy) methyl) benzene, 1,2-bis ((3-ethyl-3-oxetanylmethoxy) methyl) ethane, 1,3-bis ((3-ethyl- 3-oxetanylmethoxy) methyl) propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether, triethyleneglycolbis (3-ethyl-3 -Oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, Licyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3-ethyl-3-oxetanylmethoxy) butane 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, polyethylene glycol Bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, di Ntaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ) Ether, ditrimethylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, ethylene oxide (EO) modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, propylene oxide (PO) modified bisphenol A bis (3 -Ethyl-3-oxetanylmethyl) ether, EO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis (3- And ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl) ether, and the like.

  In addition, as the commercially available crosslinking component (2), Aron Oxetane OXT-101, 121, 221 (above, manufactured by Toagosei Co., Ltd.), OXTP, OXBP, OXIPA (above, Ube Industries) For example). These commercial products are oxetane compounds having two or more oxetane rings in each molecule.

  Among the crosslinking components (2) described above, 1,6-hexanediol diglycidyl ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, and OXIPA are preferable. The crosslinking component (2) described above can be used singly or in combination of two or more.

(Surfactant)
The resist pattern coating agent of the present invention may contain a surfactant as an optional component. The inclusion of a surfactant is preferable because the application property, antifoaming property, leveling property and the like of the resist pattern coating agent are improved. When making a resist pattern coating agent contain surfactant, it is preferable that content of surfactant is 5 mass parts or less with respect to 100 mass parts of (I) resin.

  Specific examples of the surfactant are BM-1000, BM-1100 (manufactured by BM Chemie), MegaFuck F142D, F172, F173, F183 (and above, Dainippon Ink Chemical, Inc.) under the trade names below. Manufactured by Kogyo Co., Ltd.), FLORARD FC-135, FC-170C, FC-430, FC-431 (above, manufactured by Sumitomo 3M), Surflon S-112, S-113, S-131, S -141, S-145 (above, manufactured by Asahi Glass), SH-28PA, -190, -193, SZ-6032, SF-8428 (above, manufactured by Toray Dow Corning Silicone), etc. An agent can be mentioned.

2. Resist pattern formation method:
(Process (1))
In the step (1), a first wafer, which will be described later, is applied to a silicon wafer or a substrate such as a wafer coated with SiN or an organic antireflection film by an appropriate application means such as spin coating, casting coating, or roll coating. A positive radiation sensitive resin composition (hereinafter also referred to as “first resist agent”) is applied. Thereby, the 1st resist layer which consists of a 1st resist agent can be formed. In addition, after apply | coating a 1st resist agent, you may volatilize the solvent in a coating film by prebaking (PB) as needed. Although the prebaking heating conditions are appropriately selected depending on the composition of the first resist agent, they are usually 30 to 200 ° C, preferably 50 to 150 ° C.

  In order to maximize the potential of the first resist agent, an organic or inorganic antireflection film is formed on the substrate as disclosed in, for example, Japanese Patent Publication No. 6-12458. It ’s good to leave. In order to prevent the influence of basic impurities contained in the environmental atmosphere, it is also preferable to provide a protective film on the first resist layer as disclosed in, for example, JP-A-5-188598. . It is also preferable to perform both formation of the antireflection film and formation of the protective film.

  The formed first resist layer is selectively exposed, for example, by irradiating with radiation through a mask having a predetermined pattern to form a pattern latent image portion (portion that has become insoluble in alkali by exposure). The radiation used is appropriately selected from visible rays, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams, etc., depending on the type of acid generator contained in the first resist agent, but ArF excimer laser ( Far ultraviolet rays typified by a wavelength of 193 nm) and KrF excimer laser (wavelength 248 nm) are preferred, and an ArF excimer laser (wavelength 193 nm) is particularly preferred. In addition, exposure conditions, such as exposure amount, are suitably selected according to the compounding composition of a 1st resist agent, the kind of additive, etc. Furthermore, in this invention, it is preferable to perform heat processing (PEB) after exposure. By this PEB, the dissociation reaction of the acid dissociable group in the resin component can be smoothly advanced. The heating conditions for PEB are appropriately selected depending on the composition of the resin composition, but are usually 30 to 200 ° C, preferably 50 to 170 ° C.

By developing the exposed first resist layer, the pattern latent image portion is exposed, and a positive first resist pattern having a predetermined line width L ₁ and having a predetermined space portion as shown in FIG. 1 is formed on the substrate 10. Examples of the developer that can be used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-propylamine. , Triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- An alkaline aqueous solution in which at least one of alkaline compounds such as [4.3.0] -5-nonene is dissolved is preferable. The concentration of the alkaline aqueous solution is usually 10% by mass or less. When the concentration of the alkaline aqueous solution exceeds 10% by mass, the non-exposed portion tends to be easily dissolved in the developer. In addition, after developing using alkaline aqueous solution, generally it wash | cleans with water and dries.

  An organic solvent can also be added to the alkaline aqueous solution (developer). Examples of the organic solvent that can be added include ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, and 2,6-dimethylcyclohexanone; methyl alcohol, ethyl alcohol , N-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, 1,4-hexanedimethylol, and the like; tetrahydrofuran, dioxane Ethers such as ethyl acetate, n-butyl acetate, i-amyl acetate, aromatic hydrocarbons such as toluene and xylene, phenol, acetonylacetone, dimethylformamide, etc. That. These organic solvents can be used individually by 1 type or in combination of 2 or more types.

  The addition amount of the organic solvent is preferably 100 parts by volume or less with respect to 100 parts by volume of the alkaline aqueous solution. When the addition amount of the organic solvent is more than 100 parts by volume with respect to 100 parts by volume of the alkaline aqueous solution, the developability may be deteriorated and the development residue in the exposed part may increase. An appropriate amount of a surfactant or the like can be added to the developer.

(Process (2))
In step (2), a resist pattern coating agent is applied onto the formed first resist pattern by an appropriate application means such as spin coating, cast coating, roll coating, or the like. At this time, a resist pattern coating agent is applied so that the first resist pattern is covered. After applying the resist pattern coating agent, heat treatment (baking) or UV curing is performed. By this heat treatment or UV curing, the first resist pattern is reacted with the applied resist pattern coating agent. The heating conditions are appropriately selected depending on the composition of the resist pattern coating agent, but are usually 30 to 200 ° C, preferably 50 to 170 ° C. On the other hand, for UV curing, lamps such as Ar ₂ lamp, KrCl lamp, Kr ₂ lamp, XeCl lamp, Xe ₂ lamp (USHIO Inc.) can be used.

  After appropriately cooling and developing in the same manner as in the above-described step (1), the surface of the first resist pattern 1 as shown in FIGS. 2 and 3 is an insoluble film 5 made of a resist pattern coating agent. The insolubilized resist pattern 3 that is a line-and-space pattern having the first line portion 1a and the first space portion 1b, which is covered with (1), can be formed. The insoluble film 5 is insoluble or hardly soluble in the developer and a second positive radiation-sensitive resin composition (hereinafter also referred to as “second resist agent”) described later. Therefore, the insolubilized resist pattern 3 (first line portion 1a) covered with the insoluble film 5 is insoluble or hardly soluble in the second resist agent. After development, the insolubilized resist pattern may be cured a plurality of times by heat treatment (PEB) or UV curing as necessary.

  The insolubilized first resist pattern 1 (insolubilized resist pattern 3) remains in the pattern shape even if the second resist agent is applied, exposed and developed in the following step (3) and step (4). . However, the pattern width may slightly change depending on the thickness of the applied resist pattern coating agent. In addition, you may perform this process (2) in multiple times as needed.

(Process (3))
In step (3), as shown in FIG. 4, a second resist agent, which will be described later, is applied onto the insolubilized resist pattern 3 formed on the substrate 10 by an appropriate application means such as spin coating, cast coating, roll coating or the like. The second resist layer 12 made of the second resist agent is formed by coating. Thereafter, as in the case of step (1), pre-baking (PB) may be performed as necessary. Next, similarly to the case of the step (1), the second resist layer 12 and, if necessary, the space portion of the first resist pattern (insolubilized resist pattern 3) are selectively exposed through a mask. Note that heat treatment (PEB) may be further performed as necessary.

(Process (4))
In step (4), a positive second resist pattern is formed by developing in the same manner as in step (1). Through the above steps, a resist pattern having a configuration in which a first resist pattern (insolubilized resist pattern) and a second resist pattern are sequentially added on the substrate can be formed. If the resist pattern formed in this way is used, a semiconductor can be manufactured.

  In the above-described step (3), various resist patterns having a characteristic pattern arrangement can be finally formed by appropriately selecting a mask pattern used for selective exposure. For example, as shown in FIG. 5, when the insolubilized resist pattern 3 having the first line portion 1a and the first space portion 1b is formed, the mask pattern used in the exposure in the step (3) is selected to select the second pattern. The second line portion 2a of the second resist pattern 2 having the line portion 2a and the second space portion 2b can be formed in the first space portion 1b in parallel with the first line portion 1a.

  For example, as shown in FIG. 6, the second line of the second resist pattern 22 having the second line portion 22a and the second space portion 22b is selected by selecting a mask pattern used in the exposure in the step (3). If the portion 22a is formed in a grid pattern in the first space portion 1b, a resist pattern (contact hole pattern) having the contact hole 15 defined by the first line portion 1a and the second line portion 22a of the insolubilized resist pattern is formed. be able to.

  Further, for example, as shown in FIGS. 7 and 8, if the mask pattern used in the exposure in the step (3) is selected, the second resist pattern 32 having the second line portion 32a and the second space portion 32b is selected. The two line portions 32a can be formed on the first line portion 1a so as to intersect the first line portion 1a.

(Positive radiation sensitive resin composition)
The “first positive radiation-sensitive resin composition (first resist agent)” and “second positive radiation-sensitive resin composition (second resist agent)” used in the above-described resist pattern forming method are: In any case, due to the action of the acid generated from the acid generator by exposure, the acid dissociable groups contained therein are dissociated, and the exposed portion of the resist whose solubility in the alkali developer is increased is dissolved in the alkali developer. It is removed and a positive resist pattern can be obtained.

  Both the first resist agent and the second resist agent usually contain a resin having an acid dissociable group. Furthermore, as other components, a radiation-sensitive acid generator (hereinafter also referred to as “acid generator”) and a solvent are usually contained. Hereinafter, details of the first resist agent will be described, but the details of the second resist agent are the same, and the first resist agent and the second resist agent may be the same or different. . Hereinafter, the term “resist agent” means both “first resist agent” and “second resist agent”.

(Resin having an acid dissociable group)
The resin having an acid dissociable group is preferably a resin containing one or more repeating units represented by the following general formula (5).

In Formula ^{(5), R 22} is a hydrogen or a methyl group, a plurality of ^{R 23} are independently (i) cross, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms A derivative thereof or a linear or branched alkyl group having 1 to 4 carbon atoms (provided that at least one of R ²³ is a monovalent polycyclic hydrocarbon group having 7 to 20 carbon atoms) Or (ii) a divalent polycyclic hydrocarbon group having 7 to 20 carbon atoms and containing the carbon atoms to which each two R ²³ are bonded to each other, and the rest R ²³ represents a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof.

In Formula (5), a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ²³ carbon atoms and any two of R ²³ is formed by bonding to each other, 4-20 Specific examples of the divalent alicyclic hydrocarbon group include fatty acids derived from cycloalkanes such as norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane. A group consisting of a cyclic ring; a group consisting of these alicyclic rings is, for example, a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methyl Examples include a group substituted with one or more linear, branched, or cyclic alkyl groups having 1 to 4 carbon atoms such as a propyl group and a t-butyl group. Of these, a group consisting of an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane, or cyclohexane, or a group obtained by substituting these with the above alkyl group is preferable.

Specific examples of the derivative of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ²³ in the general formula (5) include a hydroxyl group; a carboxyl group; an oxo group (that is, a ═O group). ); Hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3- A hydroxyalkyl group having 1 to 4 carbon atoms such as hydroxybutyl group and 4-hydroxybutyl group; methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1- C1-C4 alkoxyl groups such as methylpropoxy group and t-butoxy group; cyano group; cyanomethyl group, 2-cyanoethyl group, 3-cyano The group which has 1 or more types of substituents, such as C2-C5 cyanoalkyl groups, such as a propyl group and 4-cyanobutyl group, can be mentioned. Of these, a hydroxyl group, a carboxyl group, a hydroxymethyl group, a cyano group, and a cyanomethyl group are preferable.

In the general formula (5), specific examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ²³ include a methyl group, an ethyl group, an n-propyl group, and i-propyl. Group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like. Of these, a methyl group and an ethyl group are preferable.

Specific examples of the group represented by “—C (R ² ) ₃ ” in the general formula (5) include groups represented by the following general formulas (5a) to (5e) and the following formula (5f). The group represented by these can be mentioned.

In the general formulas (5a) to (5e), R ²⁴ is independently a linear or branched alkyl group having 1 to 4 carbon atoms, and m is 0 or 1. Specific examples of the linear or branched alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1- Examples thereof include a methylpropyl group and a t-butyl group. Of these, a methyl group and an ethyl group are preferable.

In the general formula (5), the portion represented by “—COOC (R ²³ ) ₃ ” is a portion which is dissociated by the action of an acid to form a carboxyl group and becomes an alkali-soluble portion. This “alkali-soluble site” is a group that becomes an anion (alkali-soluble) by the action of an alkali. On the other hand, an “acid-dissociable group” is a group in which an alkali-soluble site is protected with a protecting group, and is a group that is not “alkali-soluble” until the protecting group is removed with an acid.

  The resin having an acid-dissociable group is a resin that is itself insoluble in alkali or hardly soluble in alkali, but becomes alkali-soluble by the action of an acid. Here, “alkali insoluble or hardly soluble in alkali” means development conditions for forming a resist pattern using a resist layer comprising a resist agent containing a resin having a repeating unit represented by the general formula (5). Thus, when a film made of only a resin containing the repeating unit represented by the general formula (5) is processed (but not exposed), 50% or more of the initial film thickness of the film remains after the processing. Refers to nature. On the other hand, “alkali-soluble” refers to a property in which 50% or more of the initial film thickness of the film is lost after the same treatment.

  The ratio of the one or more repeating units represented by the general formula (5) contained in the resin having an acid dissociable group is 5 to 65 mol%, preferably 10 to 60 mol%, more preferably 15 ˜50 mol%. When the content ratio of the one or more repeating units represented by the general formula (5) is less than 5 mol% or more than 65 mol%, the first resist pattern is sufficiently obtained even when a resist pattern coating agent is used. It may be difficult to insolubilize. Moreover, it may be difficult to obtain a sufficiently insoluble resist pattern that is sufficiently stable with respect to the subsequent exposure processing or the developer and the second resist agent.

  The polystyrene-reduced weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the resin having an acid dissociable group is usually 1,000 to 500,000, preferably 1,000 to 100,000, and more Preferably it is 1,000-50,000. When Mw is less than 1,000, the heat resistance of the resist pattern to be formed tends to decrease. On the other hand, if the Mw exceeds 500,000, the developability tends to be lowered. Further, the ratio (Mw / Mn) of Mw of the resin having an acid dissociable group and the polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is preferably 1 to 5, More preferably, it is 1-3.

(Method for producing resin having acid dissociable group)
Resins having an acid-dissociable group include monomer components containing a polymerizable unsaturated monomer corresponding to a desired repeating unit, hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds, etc. The radical polymerization initiator can be used and polymerized in an appropriate solvent in the presence of a chain transfer agent as necessary.

  Examples of the solvent used for polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, norbornane. Cycloalkanes such as benzene, toluene, xylene, ethylbenzene, cumene and other aromatic hydrocarbons; chlorobutanes, bromohexanes, dichloroethanes, halogenated hydrocarbons such as hexamethylene dibromide, chlorobenzene; ethyl acetate, Saturated carboxylic acid esters such as n-butyl acetate, i-butyl acetate and methyl propionate; ethers such as tetrahydrofuran, dimethoxyethanes and diethoxyethane; methanol, ethanol, 1-propanol, 2-propanol, 1- Butanol, 2-pig Alcohol, isobutanol, 1-pentanol, 3-pentanol, 4-methyl-2-pentanol, o-chlorophenol, 2- (1-methylpropyl) phenol, etc .; acetone, 2-butanone, Mention may be made of ketones such as 3-methyl-2-butanone, 4-methyl-2-pentanone, 2-heptanone, cyclopentanone, cyclohexanone and methylcyclohexanone. These solvents can be used alone or in combination of two or more.

  Moreover, the reaction temperature in said superposition | polymerization is 40-150 degreeC normally, Preferably it is 50-120 degreeC, and reaction time is 1-48 hours normally, Preferably it is 1-24 hours. In addition, the resin having an acid dissociable group is preferable as the content of impurities such as halogen and metal is small because sensitivity, resolution, process stability, pattern profile, and the like can be improved. Examples of the purification method of the resin having an acid dissociable group include chemical purification methods such as washing with water and liquid-liquid extraction, and these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation. A combined method and the like can be given. It is preferable that the ratio of the low molecular weight component which has a monomer as a main component contained in resin which has an acid dissociable group is 0.1 mass% or less in conversion of solid content with respect to the whole resin. The content ratio of the low molecular weight component can be measured, for example, by high performance liquid chromatography (HPLC).

(Acid generator)
The resist agent preferably contains an acid generator having a structure represented by the following general formula (6), which is decomposed by exposure. By containing an acid generator in the resist agent, an acid is generated by exposure, the acid-dissociable group is dissociated, the exposed region of the resist layer becomes alkali-soluble, and a resist pattern can be formed.

In the general formula (6), R ²⁷ is a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched group having 1 to 10 carbon atoms. Or a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms. R ⁴ represents a linear or branched alkyl group or alkoxyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic alkanesulfonyl group having 1 to 10 carbon atoms.

In the general formula (6), R ²⁶ are independently of each other a linear or branched alkyl group having 1 to 10 carbon atoms, an optionally substituted phenyl group, or a substituted group. May be a naphthyl group, or two R ²⁶ may be bonded to each other to form a divalent group having 2 to 10 carbon atoms. In addition, the formed bivalent group may be substituted. k is an integer of 0 to 2, and X ⁻ is a general formula: RC _n F _2n SO ₃ ⁻ (wherein R is a fluorine atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms. N is an integer of 1 to 10), and q is an integer of 0 to 10.

In the general formula ^(6), as the R ^{25, R 26,} and linear or branched alkyl group having 1 to 10 carbon atoms represented by ^{R 27,} for example, a methyl group, an ethyl group, n- propyl Group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl Group, 2-ethylhexyl group, n-nonyl group, n-decyl group and the like. Of these, a methyl group, an ethyl group, an n-butyl group, a t-butyl group, and the like are preferable.

In the general formula (6), examples of the linear or branched alkoxyl group having 1 to 10 carbon atoms represented by R ²⁵ and R ²⁶ include a methoxy group, an ethoxy group, an n-propoxy group, i- Propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group, n-pentyloxy group, neopentyloxy group, n-hexyloxy group, n-heptyloxy group, n- An octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group, etc. can be mentioned. Of these, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group and the like are preferable.

In the general formula (6), examples of the linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms represented by R ²⁷ include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, i -Propoxycarbonyl group, n-butoxycarbonyl group, 2-methylpropoxycarbonyl group, 1-methylpropoxycarbonyl group, t-butoxycarbonyl group, n-pentyloxycarbonyl group, neopentyloxycarbonyl group, n-hexyloxycarbonyl group N-heptyloxycarbonyl group, n-octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, n-nonyloxycarbonyl group, n-decyloxycarbonyl group and the like. Of these, a methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group, and the like are preferable.

In the general formula (6), examples of the linear, branched, or cyclic alkanesulfonyl group having 1 to 10 carbon atoms represented by R ²⁵ include a methanesulfonyl group, an ethanesulfonyl group, and n-propanesulfonyl. Group, n-butanesulfonyl group, tert-butanesulfonyl group, n-pentanesulfonyl group, neopentanesulfonyl group, n-hexanesulfonyl group, n-heptanesulfonyl group, n-octanesulfonyl group, 2-ethylhexanesulfonyl group n -Nonanesulfonyl group, n-decanesulfonyl group, cyclopentanesulfonyl group, cyclohexanesulfonyl group, etc. can be mentioned. Of these, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group, a cyclohexanesulfonyl group, and the like are preferable. Moreover, q is preferably 0-2.

In the general formula (6), examples of the optionally substituted phenyl group represented by R ²⁶ include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, and 2,3-dimethylphenyl. Group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,4,6-trimethylphenyl Group, 4-ethylphenyl group, 4-t-butylphenyl group, 4-cyclohexylphenyl group, 4-fluorophenyl group and the like; linear, branched or cyclic alkyl having 1 to 10 carbon atoms A phenyl group substituted by a group; these phenyl group or alkyl-substituted phenyl group can be converted into a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxy group; Examples include a group substituted with at least one group such as an alkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group. Examples of the alkoxyl group among the substituents for the phenyl group and the alkyl-substituted phenyl group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, 1 Examples thereof include linear, branched, or cyclic alkoxyl groups having 1 to 20 carbon atoms such as a methylpropoxy group, a t-butoxy group, a cyclopentyloxy group, and a cyclohexyloxy group.

  Examples of the alkoxyalkyl group include 2 to 21 carbon atoms such as a methoxymethyl group, an ethoxymethyl group, a 1-methoxyethyl group, a 2-methoxyethyl group, a 1-ethoxyethyl group, and a 2-ethoxyethyl group. And a linear, branched, or cyclic alkoxyalkyl group. Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, a 2-methylpropoxycarbonyl group, and a 1-methylpropoxycarbonyl group. , T-butoxycarbonyl group, cyclopentyloxycarbonyl group, cyclohexyloxycarbonyl, etc., having 2 to 21 carbon atoms, such as linear, branched, or cyclic alkoxycarbonyl groups.

Examples of the alkoxycarbonyloxy group include methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, i-propoxycarbonyloxy group, n-butoxycarbonyloxy group, t-butoxycarbonyloxy group, A linear, branched, or cyclic alkoxycarbonyloxy group having 2 to 21 carbon atoms such as cyclopentyloxycarbonyl group and cyclohexyloxycarbonyl can be exemplified. In the general formula (6), the optionally substituted phenyl group represented by R ²⁶ includes a phenyl group, 4-cyclohexylphenyl group, 4-t-butylphenyl group, 4-methoxyphenyl group, 4-t -A butoxyphenyl group and the like are preferable.

In the general formula (6), examples of the optionally substituted naphthyl group represented by R ²⁶ include 1-naphthyl group, 2-methyl-1-naphthyl group, 3-methyl-1-naphthyl group, 4 -Methyl-1-naphthyl group, 4-methyl-1-naphthyl group, 5-methyl-1-naphthyl group, 6-methyl-1-naphthyl group, 7-methyl-1-naphthyl group, 8-methyl-1- Naphthyl group, 2,3-dimethyl-1-naphthyl group, 2,4-dimethyl-1-naphthyl group, 2,5-dimethyl-1-naphthyl group, 2,6-dimethyl-1-naphthyl group, 2,7 -Dimethyl-1-naphthyl group, 2,8-dimethyl-1-naphthyl group, 3,4-dimethyl-1-naphthyl group, 3,5-dimethyl-1-naphthyl group, 3,6-dimethyl-1-naphthyl Group, 3,7-dimethyl-1-naphthyl group, 3 , 8-dimethyl-1-naphthyl group, 4,5-dimethyl-1-naphthyl group, 5,8-dimethyl-1-naphthyl group, 4-ethyl-1-naphthyl group, 2-naphthyl group, 1-methyl- A naphthyl group such as a 2-naphthyl group, a 3-methyl-2-naphthyl group, and a 4-methyl-2-naphthyl group; substituted with a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms One or more of these naphthyl groups or alkyl-substituted naphthyl groups in at least one group such as a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group. Examples include substituted groups. Specific examples of the alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group, and alkoxycarbonyloxy group among these substituents include the groups exemplified for the aforementioned phenyl group and alkyl-substituted phenyl group.

In the general formula (6), the optionally substituted naphthyl group represented by R ²⁶ includes a 1-naphthyl group, a 1- (4-methoxynaphthyl) group, a 1- (4-ethoxynaphthyl) group, 1 -(4-n-propoxynaphthyl) group, 1- (4-n-butoxynaphthyl) group, 2- (7-methoxynaphthyl) group, 2- (7-ethoxynaphthyl) group, 2- (7-n- And propoxynaphthyl) group and 2- (7-n-butoxynaphthyl) group.

In the general formula (6), a divalent group of the two 2 to 10 carbon atoms R ²⁶ is bonded to each other to form a 5-membered ring also 6-membered together with the sulfur atom in the general formula (6) Groups that form a ring, preferably a 5-membered ring (ie, a tetrahydrothiophene ring) are desirable. Examples of the substituent for the divalent group include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxy group exemplified as the substituent for the phenyl group and the alkyl-substituted phenyl group. Examples thereof include a carbonyl group and an alkoxycarbonyloxy group. Incidentally, as the R ²⁶ in the general formula (6), a methyl group, an ethyl group, a phenyl group, a 4-methoxyphenyl group, 1-naphthyl group, tetrahydrothiophene two R ²⁶ are taken together with the attached to a sulfur atom each other to form a ring structure A divalent group or the like that forms is preferable.

  As the cation moiety in the general formula (6), triphenylsulfonium cation, tri-1-naphthylsulfonium cation, tri-tert-butylphenylsulfonium cation, 4-fluorophenyl-diphenylsulfonium cation, di-4-fluorophenyl- Phenylsulfonium cation, tri-4-fluorophenylsulfonium cation, 4-cyclohexylphenyl-diphenylsulfonium cation, 4-methanesulfonylphenyl-diphenylsulfonium cation, 4-cyclohexanesulfonyl-diphenylsulfonium cation, 1-naphthyldimethylsulfonium cation, 1- Naphthyldiethylsulfonium cation, 1- (4-hydroxynaphthyl) dimethylsulfonium cation, 1- (4 Methylnaphthyl) dimethylsulfonium cation, 1- (4-methylnaphthyl) diethylsulfonium cation, 1- (4-cyanonaphthyl) dimethylsulfonium cation, 1- (4-cyanonaphthyl) diethylsulfonium cation, 1- (3,5- Dimethyl-4-hydroxyphenyl) tetrahydrothiophenium cation, 1- (4-methoxynaphthyl) tetrahydrothiophenium cation, 1- (4-ethoxynaphthyl) tetrahydrothiophenium cation, 1- (4-n-propoxynaphthyl) ) Tetrahydrothiophenium cation, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium cation, 2- (7-methoxynaphthyl) tetrahydrothiophenium cation, 2- (7-ethoxynaphthyl) tetrahi B thiophenium cation, 2- (7-n- propoxy-naphthyl) tetrahydrothiophenium cation, 2- (7-n- butoxynaphthyl) can be exemplified tetrahydrothiophenium cation, or the like.

In the general formula (6), the “C _n F _2n —” group in the anion represented by X ⁻ (general formula: RC _n F _2n SO ³⁻ ) is a perfluoroalkylene group having n carbon atoms. However, the perfluoroalkylene group may be linear or branched. Note that n is preferably 1, 2, 4, or 8. The optionally substituted hydrocarbon group having 1 to 12 carbon atoms represented by R is preferably an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, or a bridged alicyclic hydrocarbon group. Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group N-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, norbornyl group, norbornylmethyl group, hydroxynorbornyl group, adamantyl group Etc.

  Preferred anion sites in the general formula (2) include trifluoromethanesulfonate anion, perfluoro-n-butanesulfonate anion, perfluoro-n-octanesulfonate anion, 2-bicyclo [2.2.1] hept-2- Yl-1,1,2,2-tetrafluoroethanesulfonate anion, 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate anion, and the like.

  Said acid generator can be used individually by 1 type or in combination of 2 or more types. It is also possible to use “other acid generators” other than the above acid generators. Specific examples of “other acid generators” include onium salt compounds, halogen-containing compounds, diazoketone compounds, sulfone compounds, and sulfonic acid compounds.

  Examples of the onium salt compounds include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like. Specific examples of the onium salt compound include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hepta-2. -Yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis ( 4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2- Te La tetrafluoroethane sulfonate, cyclohexyl 2-oxo-cyclohexyl methyl trifluoromethanesulfonate, dicyclohexyl-2-oxo-cyclohexyl trifluoromethane sulfonate, and 2-oxo-cyclohexyl dimethyl sulfonium trifluoromethanesulfonate, and the like.

  Examples of the halogen-containing compound include haloalkyl group-containing hydrocarbon compounds and haloalkyl group-containing heterocyclic compounds. Specific examples of halogen-containing compounds include (trichloromethyl such as phenylbis (trichloromethyl) -s-triazine, 4-methoxyphenylbis (trichloromethyl) -s-triazine, 1-naphthylbis (trichloromethyl) -s-triazine. ) -S-triazine derivatives and 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane.

  Examples of the diazoketone compound include a 1,3-diketo-2-diazo compound, a diazobenzoquinone compound, a diazonaphthoquinone compound, and the like. Specific examples of the diazo ketone include 1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,2, naphthoquinonediazide of 2,3,4,4′-tetrahydroxybenzophenone. -4-sulfonic acid ester or 1,2-naphthoquinonediazide-5-sulfonic acid ester; 1,1,1-naphthoquinonediazide-4-sulfonic acid ester of 1,1,1-tris (4-hydroxyphenyl) ethane Examples include 2-naphthoquinonediazide-5-sulfonic acid ester.

  Examples of the sulfone compound include β-ketosulfone, β-sulfonylsulfone, α-diazo compounds of these compounds, and the like. Specific examples of the sulfone compound include 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane, and the like.

  Examples of the sulfonic acid compounds include alkyl sulfonic acid esters, alkyl sulfonic acid imides, haloalkyl sulfonic acid esters, aryl sulfonic acid esters, and imino sulfonates. Specific examples of the sulfonic acid compounds include benzoin tosylate, pyrogallol tris (trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2.2.1] hept- 5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, perfluoro-n-octanesulfonylbicyclo [2.2 .1] Hept-5-ene-2,3-dicarbodiimide, 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonylbicyclo [2.2. 1] Hept-5-ene-2,3-dicarbodiimide, N- (trifluoromethanesulfonyl Xyl) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide, N- (perfluoro-n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonyloxy) succinimide, 1,8-naphthalenedicarboxylic imide trifluoromethanesulfonate, 1,8-naphthalenedicarboxylic imidononafluoro-n-butanesulfonate, 1,8-naphthalenedicarboxylic Examples include acid imido perfluoro-n-octane sulfonate.

  Among these “other acid generators”, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hepta. 2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, Bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2, 2-te Lafluoroethanesulfonate, cyclohexyl, 2-oxocyclohexyl, methylsulfonium trifluoromethanesulfonate, dicyclohexyl, 2-oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate, trifluoromethanesulfonylbicyclo [2.2.1] Hept-5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, perfluoro-n-octanesulfonylbicyclo [2 2.1] hept-5-ene-2,3-dicarbodiimide, 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfur Nilbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, N- (trifluoromethanesulfonyloxy) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide, N- (perfluoro- n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) succinimide, 1,8-naphthalenedicarboxylic acid Imidotrifluoromethanesulfonate and the like are preferable. These “other acid generators” can be used singly or in combination of two or more.

  It is also preferable to use an acid generator having the structure represented by the general formula (6) in combination with “another acid generator”. When “other acid generator” is used in combination, the ratio of “other acid generator” used is the sum of the acid generator having the structure represented by the general formula (6) and “other acid generator”. Is usually 80% by mass or less, preferably 60% by mass or less.

  The total amount of the acid generator contained in the resist agent is 0.1 to 20 parts by mass with respect to 100 parts by mass of the resin having an acid dissociable group from the viewpoint of ensuring the sensitivity and developability as the resist agent. It is preferable that it is 0.5 to 10 parts by mass. When the total content of the acid generator is less than 0.1 parts by mass, the sensitivity and developability of the resist agent tend to be lowered. On the other hand, if it exceeds 20 parts by mass, the transparency to radiation is lowered, and it tends to be difficult to form a rectangular resist pattern.

(solvent)
The resist agent is preferably prepared by dissolving various components including a resin having an acid dissociable group in a solvent. The solvent is preferably at least one selected from the group consisting of propylene glycol monomethyl ether acetate, 2-heptanone, and cyclohexanone (hereinafter also referred to as “solvent (1)”). In addition, a solvent other than the solvent (1) (hereinafter, also referred to as “other solvent”) can be used. Furthermore, the solvent (1) and other solvents can be used in combination.

  Examples of other solvents include propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-i-propyl ether acetate, propylene glycol mono-n-butyl ether acetate, propylene glycol mono-i- Propylene glycol monoalkyl ether acetates such as butyl ether acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol mono-t-butyl ether acetate; 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, Linear or 4-methyl-2-pentanone, 3-methyl-2-pentanone, 3,3-dimethyl-2-butanone, 2-octanone, etc. Branched ketones;

  Cyclic ketones such as cyclopentanone, 3-methylcyclopentanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, isophorone; methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, 2-hydroxypropionic acid n-propyl, i-propyl 2-hydroxypropionate, n-butyl 2-hydroxypropionate, i-butyl 2-hydroxypropionate, sec-butyl 2-hydroxypropionate, t-butyl 2-hydroxypropionate, etc. Alkyl 2-hydroxypropionates; in addition to alkyl 3-alkoxypropionates such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate,

  n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclohexanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether , Diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, propylene glycol monomethyl ether , Propylene glycol monoethyl Ether, propylene glycol mono-n-propyl ether, toluene, xylene, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, Ethyl acetoacetate, methyl pyruvate, ethyl pyruvate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, benzyl ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol Cole monoethyl ether, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, etc. Can do.

  Of these solvents, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, γ-butyrolactone and the like are preferable. . These solvents can be used singly or in combination of two or more.

  When the solvent (1) and another solvent are used in combination as the solvent, the proportion of the other solvent is usually 50% by mass or less, preferably 30% by mass or less, more preferably 25% by mass or less, based on the total amount of the solvent. It is. The amount of the solvent contained in the resist agent is such that the concentration of the total solid contained in the resist agent is usually 2 to 70% by mass, preferably 4 to 25% by mass, and more preferably 4 to 10% by mass. Is the amount.

  The resist agent is prepared by dissolving each component in a solvent so that the total solid content concentration is in the above-described numerical range to obtain a uniform solution, and then filtering with a filter having a pore size of about 0.02 μm, for example. be able to.

(Acid diffusion control agent)
The resist agent preferably contains an acid diffusion control agent. The acid diffusion control agent is a component having an action of controlling a diffusion phenomenon of an acid generated from an acid generator by exposure in a resist layer and suppressing an undesirable chemical reaction in a non-exposed region. By blending such an acid diffusion control agent, the storage stability of the resist agent is improved, the resolution of the resist is further improved, and due to fluctuations in the holding time (PED) from exposure to heat treatment after exposure. A change in the line width of the resist pattern can be suppressed, and a composition having extremely excellent process stability can be obtained. As the acid diffusion controller, it is preferable to use a nitrogen-containing organic compound or a photodisintegratable base. This photodegradable base is an onium salt compound that is decomposed by exposure and loses acid diffusion controllability.

(Nitrogen-containing organic compounds)
Examples of the nitrogen-containing organic compound include a compound represented by the following general formula (7) (hereinafter, also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule (hereinafter, “ Nitrogen-containing compound (II) ”, polyamino compounds having three or more nitrogen atoms in the same molecule and polymers thereof (hereinafter collectively referred to as“ nitrogen-containing compound (III) ”), amide group-containing compounds , Urea compounds, nitrogen-containing heterocyclic compounds, and the like.

Formula (7) in, R ^28, independently of one another, a hydrogen atom, a substituted or unsubstituted, straight, branched or cyclic alkyl group, a substituted or unsubstituted aryl group, or a substituted or non A substituted aralkyl group is shown.

  Examples of the nitrogen-containing compound (I) include mono (cyclo) alkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, cyclohexylamine; di-n- Butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, cyclohexylmethylamine, dicyclohexylamine, etc. Di (cyclo) alkylamines; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine , Tri-n-nonylamine, tri-n-decylamine, cyclohexyl Tri (cyclo) alkylamines such as dimethylamine, methyldicyclohexylamine and tricyclohexylamine; substituted alkylamines such as 2,2 ′, 2 ″ -nitrotriethanol; aniline, N-methylaniline, N, N-dimethylaniline 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, naphthylamine, 2,4,6-tri-tert-butyl-N-methylaniline, N-phenyldiethanolamine Aromatic amines such as 2,6-diisopropylaniline are preferred.

  Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, and 4,4′-diaminodiphenylether. 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2, -(4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl) ) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methyl ester Benzene], bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′ , N′-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine and the like are preferable.

  As the nitrogen-containing compound (III), for example, polyethyleneimine, polyallylamine, 2-dimethylaminoethylacrylamide polymer and the like are preferable.

  Examples of the amide group-containing compound include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt- Butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, (S)-( -)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonyl Perazine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′- Diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N′N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N′-di-t-butoxycarbonyl-1 , 7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di- t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminododecane, N, N -Di-t-butoxycarbonyl-4,4'-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole Nt-butoxycarbonyl group-containing amino compounds such as Nt-butoxycarbonylpyrrolidine, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide Propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, isocyanuric acid tris (2-hydroxyethyl) and the like are preferable.

  Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea. Etc. are preferred. Examples of the nitrogen-containing heterocyclic compound include imidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2- Imidazoles such as methyl-1H-imidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine , Nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine, pyridines such as 2,2 ′: 6 ′, 2 ″ -terpyridine; piperazine, 1- (2-hydroxyethyl ) In addition to piperazines such as piperazine, Gin, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3 -(N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane and the like are preferable.

(Photodegradable base)
A photodegradable base is an onium salt compound that generates a base that decomposes upon exposure and exhibits acid diffusion controllability. Specific examples of such an onium salt compound include a sulfonium salt compound represented by the following general formula (8) and an iodonium salt compound represented by the following general formula (9).

In the general formulas (8) and (9), R ^{29 to} R ³³ each independently represent a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom. Z ⁻ represents OH ⁻ , R—COO ⁻ , R—SO ₃ ^— (wherein R represents an alkyl group, an aryl group, or an alkaryl group), or an anion represented by the following formula (10). Show.

  Specific examples of the sulfonium salt compound and the iodonium salt compound include triphenylsulfonium hydroxide, triphenylsulfonium acetate, triphenylsulfonium salicylate, diphenyl-4-hydroxyphenylsulfonium hydroxide, diphenyl-4-hydroxyphenylsulfonium acetate, Diphenyl-4-hydroxyphenylsulfonium salicylate, bis (4-t-butylphenyl) iodonium hydroxide, bis (4-t-butylphenyl) iodonium acetate, bis (4-t-butylphenyl) iodonium hydroxide, bis (4-t-butylphenyl) iodonium acetate, bis (4-t-butylphenyl) iodonium salicylate, 4-t-butyl Enyl-4-hydroxyphenyliodonium hydroxide, 4-t-butylphenyl-4-hydroxyphenyliodonium acetate, 4-t-butylphenyl-4-hydroxyphenyliodonium salicylate, bis (4-t-butylphenyl) iodonium Examples thereof include 10-camphor sulfonate, diphenyliodonium 10-camphor sulfonate, triphenylsulfonium 10-camphor sulfonate, and 4-t-butoxyphenyl diphenylsulfonium 10-camphor sulfonate.

  The above acid diffusion control agents can be used singly or in combination of two or more. The compounding amount of the acid diffusion controller is usually 15 parts by mass or less, preferably 10 parts by mass or less, and more preferably 5 parts by mass or less with respect to 100 parts by mass of the resin having an acid dissociable group. If the compounding amount of the acid diffusion controller is more than 15 parts by mass, the sensitivity of the resist agent tends to decrease. If the amount of the acid diffusion control agent is less than 0.001 part by mass, the shape and dimensional fidelity of the resist pattern may be lowered depending on the process conditions.

(Additive)
Various additives such as a surfactant, a sensitizer, and an aliphatic additive can be blended with the resist agent as necessary.

  A surfactant is a component that exhibits an effect of improving coating properties, striation, developability, and the like. Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, and polyethylene glycol dilaurate. Nonionic surfactants such as polyethylene glycol distearate; hereinafter referred to as KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (above, manufactured by Tochem Products), Megafax F171, F173 (above, manufactured by Dainippon Ink and Chemicals), Florad FC430, FC431 (above, manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( As mentioned above, Asahi Glass Co., Ltd.) can be mentioned. These surfactants can be used singly or in combination of two or more. The compounding quantity of surfactant is normally 2 mass parts or less with respect to 100 mass parts of hydroxyl-containing resin.

  The sensitizer absorbs radiation energy and transmits the energy to the acid generator, thereby increasing the amount of acid generated, and has the effect of improving the apparent sensitivity of the resist agent. Have. Examples of such sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like. These sensitizers can be used individually by 1 type or in combination of 2 or more types. Further, by blending a dye or a pigment, the latent image in the exposed area can be visualized, and the influence of halation during exposure can be reduced. Furthermore, adhesiveness with a board | substrate can be improved by mix | blending an adhesion aid. The compounding quantity of a sensitizer is 50 mass parts or less normally with respect to 100 mass parts of hydroxyl-containing resin.

  Examples of the alicyclic additive that can be added to the resist agent include an alicyclic additive having an acid dissociable group and an alicyclic additive having no acid dissociable group. Such an alicyclic additive is a component having an effect of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Specific examples of the alicyclic additive include 1-adamantanecarboxylic acid, 2-adamantanone, 1-adamantanecarboxylic acid t-butyl, 1-adamantanecarboxylic acid t-butoxycarbonylmethyl, 1-adamantanecarboxylic acid α-butyrolactone Ester, 1,3-adamantane dicarboxylate di-t-butyl, 1-adamantane acetate t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantane diacetate di-t-butyl, 2,5- Adamantane derivatives such as dimethyl-2,5-di (adamantylcarbonyloxy) hexane; deoxycholic acid t-butyl, deoxycholic acid t-butoxycarbonylmethyl, deoxycholic acid 2-ethoxyethyl, deoxycholic acid 2-cyclohexyloxy Ethyl, deoxycholic acid -Deoxycholic acid esters such as oxocyclohexyl, deoxycholic acid tetrahydropyranyl, deoxycholic acid mevalonolactone ester; lithocholic acid t-butyl, lithocholic acid t-butoxycarbonylmethyl, lithocholic acid 2-ethoxyethyl, lithocholic acid 2 -Lithocholic acid esters such as cyclohexyloxyethyl, lithocholic acid 3-oxocyclohexyl, lithocholic acid tetrahydropyranyl, lithocholic acid mevalonolactone ester; dimethyl adipate, diethyl adipate, dipropyl adipate, di-n-butyl adipate, Alkyl carboxylic acid esters such as di-t-butyl adipate; 3- [2-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.12,5.17,10] A dodecane etc. can be mentioned.

  These alicyclic additives can be used singly or in combination of two or more. The compounding quantity of an alicyclic additive is 50 mass parts or less normally with respect to 100 mass parts of hydroxyl-containing resin, Preferably it is 30 mass parts or less. When the blending amount of the alicyclic additive is more than 50 parts by mass with respect to 100 parts by mass of the hydroxyl group-containing resin, the heat resistance as a resist tends to decrease. Furthermore, examples of additives other than the above include alkali-soluble resins, low-molecular alkali solubility control agents having an acid-dissociable protecting group, antihalation agents, storage stabilizers, antifoaming agents, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

  [Weight average molecular weight (Mw) and number average molecular weight (Mn)]: Tosoh GPC columns (trade name “G2000HXL”, trade name “G3000HXL”, trade name “G4000HXL”) are used. , Flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under analysis conditions of 40 ° C. The degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

  [Remaining ratio of low molecular weight component (%)]: Using a trade name “Inertsil ODS-25 μm column” (4.6 mmφ × 250 mm) manufactured by GL Sciences, flow rate: 1.0 mL / min, elution solvent: acrylonitrile / It was measured by high performance liquid chromatography (HPLC) under the analysis condition of 0.1% phosphoric acid aqueous solution. The “low molecular weight component” refers to a component having a monomer as a main component, specifically a component composed of a compound having a molecular weight of less than 1,000, more specifically a component composed of a compound having a molecular weight equal to or less than that of the trimer. .

[ ¹³ C-NMR analysis]: The product name “JNM-EX270” manufactured by JEOL Ltd. was used, and CDCl ₃ was used as a measurement solvent.

  [Evaluation of pattern]: Using a scanning electron microscope (trade name “S-9380”, manufactured by Hitachi Keiki Co., Ltd.), the resist patterns formed on the evaluation substrates B and C were evaluated according to the following criteria.

<Evaluation board B>
The case where the first resist pattern remained was evaluated as “◯”, and the case where the first resist pattern disappeared was evaluated as “x”.

<Evaluation substrate C>
A case where a line and space pattern of 50 nm line / 100 nm pitch (50 nm 1 L / 1 S) was additionally formed between the insolubilized resist patterns formed on the evaluation substrate B was evaluated as “◯”. On the other hand, when (i) the insolubilized resist pattern has disappeared, (ii) the second resist pattern is not formed, or (iii) the insolubilized resist pattern remains undissolved even if the second resist pattern is formed Was evaluated as “×”.

  [Evaluation of Curing Performance]: An unexposed area of 10 μm × 10 μm or more in the insolubilized resist pattern of the substrate for evaluation C is cured by exposure at the time of forming the second resist pattern without causing a hole or peeling in the unexposed area. The case where it was done was evaluated as “◯”, and the case where it was damaged (when a hole or peeling occurred) was evaluated as “x”.

(Synthesis Example 1: Resin (A-1) having an acid dissociable group)
50.16 g (50 mol%) of the compound represented by the following formula (L-1), 39.14 g (37 mol%) of the compound represented by the following formula (L-2), and the following formula (L-3) 10.70 g (13 mol%) of the compound represented by formula (1) is dissolved in 200 g of 2-butanone, and 5.58 g of dimethyl 2,2′-azobis (2-methylpropionate) is further added to the monomer solution. Was prepared. A 1000 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization reaction, the polymer solution was cooled to 30 ° C. or less by water cooling, and then poured into 2000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdered resin (A-1) (78 g, yield 78%). ). Mw of the obtained resin (A-1) was 5,200, Mw / Mn was 1.62, and the residual ratio of the low molecular weight component was 0.03%. Moreover, it has a repeating unit represented by a following formula (A-1) as a result of < ¹³ > C-NMR analysis, The content rate (mol%) of each repeating unit is a / b / c = 50.0 / It was 37.0 / 13.0.

(Synthesis Example 2: Resin (A-2) having an acid dissociable group)
In place of the compound represented by the formula (L-3), 19.86 g (25 mol%) of a compound represented by the following formula (L-4) was used, and represented by the formula (L-1). Except that 52.47 g (50 mol%) of the compound to be used and 27.66 g (25 mol%) of the compound represented by the formula (L-2) were used, Similarly, resin (A-2) was obtained (78 g, yield 78%). Mw of the obtained resin (A-2) was 5,490, Mw / Mn was 1.52, and the residual ratio of the low molecular weight component was 0.03%. Moreover, it has a repeating unit represented by a following formula (A-2) as a result of < ¹³ > C-NMR analysis, The content rate (mol%) of each repeating unit is a / b / c = 50.3 / It was 24.7 / 25.0.

(Synthesis Example 3: Resin (A-3) having an acid dissociable group)
38.74 g (40 mol%) of the compound represented by the formula (L-1) and 61.26 g (60 mol%) of the compound represented by the formula (L-2) were dissolved in 200 g of 2-butanone. Further, 3.58 g of dimethyl 2,2′-azobis (2-methylpropionate) was added to prepare a monomer solution. A 1000 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization reaction, the polymer solution was cooled to 30 ° C. or less by water cooling, and then poured into 2000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdered resin (A-3) (78 g, 78% yield). ). Mw of the obtained resin (A-3) was 5,400, Mw / Mn was 1.60, and the residual ratio of the low molecular weight component was 0.03%. ^Further, 13 C-NMR analysis revealed that a repeating unit represented by the following formula (A-3), the content of each repeating unit (mol%) is, a / b = 41.0 / 59 . 0.

(Synthesis Example 4: Resin (A-4) having an acid dissociable group)
53.93 g (50 mol%) of the compound represented by the formula (L-1), 10.69 g (10 mol%) of the compound represented by the following formula (L-5), and the following formula (L-6) 35.38 g (40 mol%) of the compound represented by formula (1) is dissolved in 200 g of 2-butanone, and 3.58 g of dimethyl 2,2′-azobis (2-methylpropionate) is further added to the monomer solution. Was prepared. A 1000 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization reaction, the polymer solution was cooled to 30 ° C. or less by water cooling, and then poured into 2000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdered resin (A-4) (82 g, yield 82%). ). Mw of the obtained resin (A-4) was 5,800, Mw / Mn was 1.61, and the residual ratio of the low molecular weight component was 0.03%. Moreover, it has a repeating unit represented by a following formula (A-4) as a result of < ¹³ > C-NMR analysis, and the content rate (mol%) of each repeating unit is 53.0 / 9.8 / 37. 2.

(Synthesis Example 5: Resin (A-5) having an acid dissociable group)
In place of the compound represented by the formula (L-2), 24.42 g (15 mol%) of a compound represented by the following formula (L-7) was used, and represented by the formula (L-3). In place of the compound, 30.40 g (40 mol%) of the compound represented by the following formula (L-8) was used, and 45.18 g of the compound represented by the formula (L-1) ( (45 mol%) A resin (A-5) was obtained in the same manner as in Synthesis Example 1 except that it was used (75 g, yield 75%). Mw of the obtained resin (A-5) was 6,100, Mw / Mn was 1.73, and the residual ratio of the low molecular weight component was 0.04%. Moreover, as a result of ¹³ C-NMR analysis, it has a repeating unit represented by the following formula (A-5), and the content (mol%) of each repeating unit is a / b / c = 44.1 / It was 15.5 / 40.4.

(Preparation of resist agent)
Using the resin having an acid-dissociable group synthesized in Synthesis Examples 1 to 5, an acid generator, an acid diffusion controller, and a solvent, the first resist agents (1) to (4) according to the formulation shown in Table 1, And the 2nd resist agent (5) was prepared.

  In addition, the types of the acid generator, the acid diffusion controller, and the solvent that are abbreviated in Table 1 are shown below.

<(B) Acid generator>
(B-1): 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro-n-butanesulfonate (B-2): triphenylsulfonium nonafluoro-n-butanesulfonate

<(C) Acid diffusion controller>
(C-1): tert-butyl-4-hydroxy-1-piperidinecarboxylate (C-2): triphenylsulfonium salicylate

<(D) Solvent>
(D-1): Propylene glycol monomethyl ether acetate (D-2): γ-butyrolactone

(Synthesis Example 6: Resin (I-1))
62.13 g of p-hydroxymethacrylanilide (m-1), 37.87 g of pt-butoxystyrene (m-2), and 10.21 g of azobisisobutyronitrile (AIBN) are dissolved in 300 g of isopropanol (IPA). Then, the polymerization reaction was performed for 6 hours under reflux conditions (82 ° C.). After cooling the reaction vessel with running water, 200 g of ethyl acetate, 140 g of IPA, and 140 g of methanol were added to homogenize, and 600 g of water was further added and left to stand for 1 hour. The viscous polymer that settled in the lower layer was collected and vacuum-dried at 50 ° C. to obtain resin (I-1) (yield 70%). Mw of the obtained resin (I-1) was 8500, and Mw / Mn was 2.08. As a result of ¹³ C-NMR analysis, the ratio (molar ratio) of repeating units contained in the obtained resin (I-1) was (m−1) / (m−2) = 55.4 / 44. 6. The structures of p-hydroxymethacrylanilide (m-1) and pt-butoxystyrene (m-2) are shown below.

(Synthesis Example 7: Resin (I-2))
17.62 g of p-hydroxymethacrylanilide (m-1), 10.22 g of pt-butoxystyrene (m-2), 2-(((trifluoromethyl) sulfonyl) amino) ethyl-1-methacrylate (m- 3) 2.16 g and 2.18 g of AIBN were dissolved in 90 g of IPA, and a polymerization reaction was performed for 6 hours under reflux conditions (82 ° C.). After cooling the reaction vessel with running water, 60 g of ethyl acetate, 42 g of IPA, and 42 g of methanol were added and homogenized, and 180 g of water was further added and left to stand for 1 hour. The viscous polymer that settled in the lower layer was collected and vacuum dried at 50 ° C. to obtain a resin (I-2) (yield 77%). Mw of the obtained resin (I-2) was 7800, and Mw / Mn was 1.50. In addition, as a result of ¹³ C-NMR analysis, the ratio (molar ratio) of repeating units contained in the obtained resin (I-2) was (m−1) / (m−2) / (m−3) = It was 54.2 / 41.3 / 4.5. The structure of 2-(((trifluoromethyl) sulfonyl) amino) ethyl-1-methacrylate (m-3) is shown below.

(Example 1: Resist pattern coating agent (1))
100 parts of resin (I-1), 5 parts of crosslinking component (E-1), 30 parts of crosslinking component (E-2), 1 part of a radical generator represented by the following formula (1-A), solvent (D- 3) After mixing 524 parts and 2096 parts of solvent (D-4) and stirring for 3 hours, the resist pattern coating agent (1) was prepared by filtering using a filter with a pore diameter of 0.03 μm. In addition, the radical generator represented by the following formula (1-A) is a mixture of a plurality of compounds in which n in the following formula (1) is represented by 1 to 10.

(Examples 2 to 6: resist pattern coating agents (2) to (6))
Resist pattern coating agents (2) to (6) were prepared in the same manner as in Example 1 except that the formulation shown in Table 2 was used.

  The types of crosslinking components and solvents abbreviated in Table 2 are shown below.

<(E) Crosslinking component>
(E-1): Product name “Nicalak MX-750” (manufactured by Nippon Carbide)
(E-2): Product name “OXIPA” (manufactured by Ube Industries)
(E-3): Pentaerythritol triacrylate

<(D) Solvent>
(D-3): 1-butanol (D-4): 4-methyl-2-pentanol

(Reference Example 1)
A 12-inch silicon wafer was spin-coated with a lower antireflection film (trade name “ARC29A”, manufactured by Brewer Science) using a trade name “CLEAN TRACK ACT12” (manufactured by Tokyo Electron), and then PB (205 (C, 60 seconds) to form a 77 nm-thickness coating film. Using the trade name “CLEAN TRACK ACT12”, spin coat the first resist agent (1), PB (115 ° C., 60 seconds), and then cool (23 ° C., 30 seconds) to coat 150 nm thick. A film was formed. Next, using an ArF immersion exposure apparatus (trade name “XT1250i”, manufactured by ASML), NA: 0.85, Outer / Inner = 0.89 / 0.59 Annular optical conditions, 50 nm line / 200 nm pitch The exposure was carried out through a mask having a mask size of. After PEB (115 ° C., 60 seconds) on a hot plate of the trade name “CLEAN TRACK ACT12”, it was cooled (23 ° C., 30 seconds), and 2.38% tetramethylammonium hydroxide was used with the LD nozzle of the developing cup. Paddle development (30 seconds) was performed using the aqueous solution as a developer, and rinsed with ultrapure water. The substrate A for evaluation on which the first resist pattern was formed was obtained by spin-drying by shaking off at 2000 rpm for 15 seconds.

  After spin-coating the resist pattern coating agent (1) on the first resist pattern of the obtained evaluation substrate A using the trade name “CLEAN TRACK ACT12” and applying the film thickness to 150 nm, PB before washing (130 ° C., 60 seconds) was performed. Using the product name “CLEAN TRACK ACT12”, cooling with a cooling plate at 23 ° C. for 30 seconds, and then using a LD nozzle of the developing cup with a 2.38% tetramethylammonium hydroxide aqueous solution as a developer for paddle development (60 seconds) And rinsed with ultrapure water. Spin-drying was performed by shaking off at 2000 rpm for 15 seconds. After cleaning, PB (165 ° C., 90 seconds) was performed to obtain an evaluation substrate B on which an insolubilized resist pattern was formed.

(Reference Examples 2-12)
Each evaluation substrate B on which an insolubilized resist pattern was formed in the same manner as in Reference Example 1 except that the first resist agent and the resist pattern coating agent shown in Table 3 were used and the conditions shown in Table 3 were used. Got.

(Example 7)
After spin-coating the second resist agent (5) on the insolubilized resist pattern of the evaluation substrate B obtained in Reference Example 1 using the trade name “CLEAN TRACK ACT12” and performing PB (100 ° C., 60 seconds) Then, it was cooled (23 ° C., 30 seconds) to form a coating film having a thickness of 150 nm. Using an ArF immersion exposure apparatus, the space of the insolubilized resist pattern through a mask having a mask size of 50 nm line / 200 nm pitch under the optical conditions of NA: 0.85 and Outer / Inner = 0.89 / 0.59 Annular The part was exposed. After PEB (95 ° C., 60 seconds) on a hot plate of the trade name “CLEAN TRACK ACT12”, it was cooled (23 ° C., 30 seconds), and 2.38% tetramethylammonium hydroxide was used in the LD nozzle of the developing cup. Paddle development (30 seconds) was performed using the aqueous solution as a developer, and rinsed with ultrapure water. The substrate for evaluation C on which the second resist pattern was formed was obtained by spin-drying by shaking off at 2000 rpm for 15 seconds. The evaluation result of the pattern of the obtained substrate for evaluation C was “◯”, and the evaluation result of the curing performance was “◯”.

(Examples 8 to 18)
Evaluation in which the second resist pattern was formed in the same manner as in Example 7 except that each evaluation substrate B shown in Table 4 and the second resist agent were used and the conditions shown in Table 4 were used. Substrate C was obtained. Table 4 shows the evaluation results of the pattern of the obtained evaluation substrate C and the evaluation results of the curing performance.

  As is apparent from the results shown in Table 4, it can be seen that by using a resist pattern coating agent containing a radical generator, it is possible to form a second resist pattern and improve the performance.

  If the resist pattern coating agent of this invention is used, the fine pattern exceeding a wavelength limit can be formed economically with high precision. The resist pattern forming method of the present invention can be very suitably employed in the field of microfabrication represented by the manufacture of integrated circuit elements that are expected to be increasingly miniaturized in the future.

1: first resist pattern, 1a: first line portion, 1b: first space portion, 2, 22, 32: second resist pattern, 2a, 22a, 32a: second line portion, 2b, 22b, 32b : Second space part, 3: insolubilized resist pattern, 5: insoluble film, 10: substrate, 12: second resist layer, 15: contact hole

Claims (3)

(I) a resin comprising a structural unit derived from at least one monomer of hydroxyacrylanilide and hydroxymethacrylanilide;
(II) a radical generator;
Containing a resist pattern coating agent. The resist pattern coating agent according to claim 1, wherein the radical generator (II) is a compound containing a repeating unit represented by the following general formula (1).

(In the general formula (1), A represents an alkyl group of 1 to 20, a saturated cyclic group, or an aromatic ring, and R ¹ , R ² , and R ³ are each independently a hydrogen atom, carbon, A linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxyl group having 1 to 8 carbon atoms, or a hydroxyl group) (1) A step of selectively exposing a first resist layer formed on a substrate using the first positive-type radiation-sensitive resin composition and developing the first resist layer to form a first resist pattern ( 1) and
(2) On the first resist pattern, the resist pattern coating agent according to claim 1 or 2 is applied, baked or UV cured, and then washed, and the first resist pattern is developed with a developer and a first resist pattern. A step (2) for forming an insolubilized resist pattern insoluble in the second positive-type radiation-sensitive resin composition;
(3) A step of forming a second resist layer on the insolubilized resist pattern using the second positive-type radiation-sensitive resin composition, and selectively exposing the formed second resist layer ( 3) and
(4) A step (4) of developing to form a second resist pattern.

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