JP4706562B2 - Method for forming resist pattern - Google Patents

Description

The present invention relates to a method of forming a resist pattern comprising an immersion exposure step of irradiating radiation through the immersion exposure liquid. More specifically, during the immersion exposure process, when the substrate with the photoresist film is placed in an immersion exposure liquid such as water, the amount of a substance eluted from the photoresist film can be reduced. The present invention relates to a method for forming a resist pattern , which can form a photoresist film having a good cross-sectional shape and a high resolution and depth of focus.

In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, a lithography technique capable of microfabrication at a level of 0.10 μm or less is required. However, in the conventional lithography process, near ultraviolet rays such as i rays 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 0.20 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, an X-ray, an electron beam, etc. Among them, in particular, a KrF excimer laser (wavelength 248 nm) or An ArF excimer laser (wavelength: 193 nm) has attracted attention.
As a resist suitable for irradiation with such an excimer laser, a component having an acid-dissociable group and a component that generates acid upon irradiation with radiation (hereinafter also referred to as “exposure”) (hereinafter referred to as “acid generator”). )) And a resist utilizing the chemical amplification effect (hereinafter 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. In this resist, a 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, it utilizes the phenomenon that the exposed area of the resist becomes readily soluble in an alkaline developer.

  In such a lithography process, further fine pattern formation (for example, a fine resist pattern having a line width of about 90 nm) is required. In order to achieve such a pattern formation finer than 90 nm, 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, a new expensive exposure apparatus is required to shorten the light source wavelength. 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.

  Recently, a liquid immersion lithography (liquid immersion lithography) method has been reported as a lithography technique that can solve such problems. In this method, at the time of exposure, a liquid refractive index medium (immersion liquid) such as pure water or a fluorine-based inert liquid having a predetermined thickness is interposed on at least the photoresist film between the lens and the photoresist film on the substrate. It is to let you. In this method, a light source having the same exposure wavelength can be 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. Similar to 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. If such immersion exposure is used, it is possible to realize the formation of a resist pattern that is low in cost, excellent in high resolution, and excellent in depth of focus, using a lens mounted on an existing apparatus. It is attracting a lot of attention.

However, in the above immersion exposure process, the photoresist film is directly brought into contact with a high refractive index liquid (immersion liquid) such as water at the time of exposure, so that the acid generator and the like are eluted from the photoresist film before the exposure. There is a possibility. If the amount of the eluate is large, the immersion liquid contains impurities, and there is a problem that the lens is damaged, a predetermined pattern shape cannot be obtained, or sufficient resolution cannot be obtained.
Therefore, it has been eagerly desired to further reduce the amount of elution of the acid generator or the like into the immersion liquid in the resist used in the immersion exposure apparatus.
As a resin for forming a resist film used in an immersion exposure apparatus, for example, resins described in Patent Document 1 and Patent Document 2 have been proposed. However, even with resists using these resins, the depth of focus is not always sufficient.

International Publication WO 2004-068242 JP 2005-173474 A

The object of the present invention is to reduce the amount of a substance eluted from a photoresist film when the substrate with a photoresist film is placed in an immersion exposure liquid such as water during the immersion exposure process. , the cross-sectional shape of the resulting resist pattern is good, there is provided a method of forming a resist pattern capable of forming a photoresist film which is excellent in resolution and depth of focus.

〔式中、Ｒ ^１ は、水素原子、メチル基又はトリフルオロメチル基であり、Ｒ ^３ は、互いに同一又は異なる有機基であり、２つのＲ ^３ により環構造を形成してもよい。〕 As a means for achieving the above object, the invention of claim 1 is characterized in that an immersion exposure liquid having a refractive index higher than that of air at a wavelength of 193 nm is interposed between a lens and a photoresist film, and the radiation is transmitted. a method of forming a resist pattern including immersion exposure for irradiating the photoresist film, the photoresist is that the radiation-sensitive resin composition used to form the coating, a resin, a photoacid generator, including A repeating unit [1] represented by the following general formula (2) containing a nitrogen compound and a solvent, wherein the resin has a structure that exhibits alkali solubility by the action of an acid. content] is, relative to the total amount of the repeating units constituting the resin, a method of forming a resist pattern, characterized in that at least 60 mol%.

[Wherein, R ¹ is a hydrogen atom, a methyl group or a trifluoromethyl group, R ³ is the same or different organic group, and two R ³ may form a ring structure. ]

〔式中、Ｒ^１は、水素原子、メチル基又はトリフルオロメチル基であり、Ｒ^２は、炭素数１〜４の直鎖状又は分岐状のアルキル基である。〕 The invention of claim 2 is the method for forming a resist pattern according to claim 1, wherein the repeating unit [1] includes a repeating unit represented by the following general formula (1).

[Wherein, R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms. ]

The invention according to claim 3 is the method for forming a resist pattern according to claim 1 or 2, wherein the resin further contains a repeating unit having a lactone structure.

According to the present invention, during the immersion exposure process using a substrate with a photoresist film obtained by forming a photoresist film made of the composition used in the present invention on the surface of a silicon substrate or the like, the photoresist film is applied. When the substrate is placed in an immersion exposure liquid such as water, the amount of the substance eluted from the photoresist film can be reduced, and the cross-sectional shape of the resulting resist pattern is good, and the resolution and depth of focus are improved. Also excellent.
Moreover, according to the present invention, a resist pattern having excellent resolution and depth of focus and a good cross-sectional shape can be obtained.

  Hereinafter, the present invention will be described in detail. In the present specification, “(meth) acryl” means acryl and methacryl, and “(meth) acrylate” means acrylate and methacrylate.

〔式中、Ｒ ^１ は、水素原子、メチル基又はトリフルオロメチル基であり、Ｒ ^３ は、互いに同一又は異なる有機基であり、２つのＲ ^３ により環構造を形成してもよい。〕 1. The radiation-sensitive resin composition used in the radiation-sensitive resin composition (hereinafter, referred to as. "Composition of the present invention") includes a resin, a photoacid generator, a nitrogen-containing compound, and a solvent Containing the repeating unit [1] represented by the following general formula (2) , wherein the resin has a structure expressing alkali solubility by the action of an acid, and the content of the repeating unit [1] is It is characterized by being 60 mol% or more with respect to the total amount of repeating units constituting the resin.

[Wherein, R ¹ is a hydrogen atom, a methyl group or a trifluoromethyl group, R ³ is the same or different organic group, and two R ³ may form a ring structure. ]

1-1. Resin The resin used in the present invention (hereinafter also referred to as “resin [A]”) is alkali-soluble by the action of an acid, regardless of whether it is a single type or two or more types. It is an alkali-insoluble or hardly alkali-soluble resin. The term “alkali insoluble or alkali poorly soluble” means that under the alkali development conditions employed when a resist pattern is formed from a photoresist film comprising a radiation sensitive resin composition containing the resin [A], When a film consisting only of the resin [A] is developed instead of the resist film, it means that 50% or more of the initial film thickness of the film remains after development.

The content “60 mol% or more” of the repeating unit [1] constituting the resin [A] is not limited to the case where one resin is used alone or two or more resins are used. When the total amount of the repeating units constituting each resin is 100 mol%, the content of the repeating unit [1] is 60 mol% or more. When the content of the repeating unit [1] is 60 mol% or more, a substrate with a photoresist film provided with a photoresist film made of the composition of the present invention is subjected to a liquid such as water during the immersion exposure process. The amount of the substance eluted from the photoresist film when placed in the immersion exposure liquid can be reduced, the resulting resist pattern has a good cross-sectional shape, and excellent resolution and depth of focus.
The content of the repeating unit [1] is preferably 65 mol% or more, more preferably 70 mol% or more, still more preferably 75 mol% or more. In addition, the upper limit of the content of the repeating unit [1] is usually 98 mol%, preferably 95 mol%, more preferably 90 mol%.

〔式中、Ｒ^１は、水素原子、メチル基又はトリフルオロメチル基であり、Ｒ^３は、互いに同一又は異なる有機基であり、２つのＲ^３により環構造を形成してもよい。〕
上記樹脂〔Ａ〕は、上記一般式（２）で表される単位を１種のみ含んでよいし、２種以上を含んでもよい。 As the repeating unit [1] , a unit represented by the following general formula (2) is used as described above .

[Wherein, R ¹ is a hydrogen atom, a methyl group or a trifluoromethyl group, R ³ is the same or different organic group, and two R ³ may form a ring structure. ]
The resin [A] may contain only one type of unit represented by the general formula (2), or may contain two or more types.

In the general formula (2), preferable R ³ is as follows. That is, each R ³ is independently a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. More preferable R ³ satisfies the following condition (i) or (ii).
(I) At least one R ³ is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.
(Ii) Two R ³ are bonded to each other to have a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative structure thereof, and the remaining R ³ is a monovalent fat having 4 to 20 carbon atoms. It is a cyclic hydrocarbon group or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms.

In the general formula (2), a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms as R ³ and a divalent hydrocarbon having 4 to 20 carbon atoms formed by two R ³ bonded together. The alicyclic hydrocarbon group consists of alicyclic rings derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, etc. Group, and a group consisting of these alicyclic rings, a hydrogen atom is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group, Examples thereof include a group substituted with one or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as a tert-butyl group. Among these alicyclic hydrocarbon groups, a group consisting of an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane, a group consisting of these alicyclic rings, A group in which an atom is substituted with the alkyl group is preferable.

  In addition, as the derivative of the alicyclic hydrocarbon group, in the alicyclic hydrocarbon group, a hydrogen atom is a hydroxyl group; a carboxyl group; an oxo group (that is, ═O group); a hydroxymethyl group, 1-hydroxy Ethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group A C1-C4 hydroxyalkyl group such as methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, tert-butoxy group, etc. C1-C4 alkoxyl group; cyano group; cyanomethyl group, 2-cyanoethyl group, 3-cyanopropyl , Such substituted radicals with one or more or one or more such cyanoalkyl group having 2 to 5 carbon atoms such as 4-cyanobutyl group. Of these, a group substituted by a hydroxyl group, a carboxyl group, a hydroxymethyl group, a cyano group, a cyanomethyl group or the like is preferable.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms as R ³ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-methylpropyl group, 1 -A methylpropyl group, a tert-butyl group, etc. are mentioned. Of these alkyl groups, a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are preferable.

〔各式中、Ｒ^４は、互いに独立して炭素数１〜４の直鎖状もしくは分岐状のアルキル基であり、ｐは、０又は１である。〕
上記各態様において、炭素原子に結合する水素原子が、ヒドロキシル基、シアノ基に置換されてなる基であってもよい。また、隣接する炭素原子どうしと、他の炭素原子、酸素原子等とによって新たに環構造を形成された基であってもよい。 The group —COOC (R ³ ) ₃ in the general formula (2) has a structure that is dissociated by the action of an acid and expresses a carboxyl group, ie, alkali solubility by the action of an acid. Specific examples of the skeleton constituting such a group —COOC (R ³ ) ₃ are shown below.

[In the formulas, R ⁴ is a linear or branched alkyl group having 1 to 4 carbon atoms independently of one another, p is 0 or 1. ]
In each of the above embodiments, the hydrogen atom bonded to the carbon atom may be a group formed by substitution with a hydroxyl group or a cyano group. Further, it may be a group in which a ring structure is newly formed by adjacent carbon atoms and other carbon atoms, oxygen atoms or the like.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms as the group R ⁴ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a 2-methylpropyl group, 1 -A methylpropyl group, a tert-butyl group, etc. are mentioned. Of these, a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are preferable.

〔式中、Ｒ^１は、水素原子、メチル基又はトリフルオロメチル基であり、Ｒ^４は、炭素数１〜４の直鎖状又は分岐状のアルキル基である。〕 In the embodiment (a), a group where p = 0 is preferable, and a unit containing the group is specifically represented by the following general formula (3).

[Wherein, R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁴ represents a linear or branched alkyl group having 1 to 4 carbon atoms. ]

  As a compound which forms the repeating unit represented by the general formula (3), (meth) acrylic acid 1-methyl-1-cyclopentyl ester, (meth) acrylic acid 1-ethyl-1-cyclopentyl ester, (meth) Examples include acrylic acid 1-propyl-1-cyclopentyl ester, (meth) acrylic acid 1-isopropyl-1-cyclopentyl ester, and the like. Of these, (meth) acrylic acid 1-methyl-1-cyclopentyl ester and (meth) acrylic acid 1-ethyl-1-cyclopentyl ester are preferred.

  In the above embodiment (a), examples of the compound that forms a repeating unit having a group where p = 1 include (meth) acrylic acid 1-methyl-1-cyclohexyl ester, (meth) acrylic acid 1-ethyl-1 -Cyclohexyl ester etc. are mentioned.

In the above embodiment (b), a group in which R ⁴ is a methyl group, an ethyl group, an n-propyl group or an isopropyl group is preferable. In the above embodiment (c), a group in which two R ^{4 s} are both methyl groups is preferable. In the above embodiment (d), a group in which two R ^{4 s} are both methyl groups is preferable.

As a compound which forms the repeating unit which has group of said aspect (b)-(d), (meth) acrylic-acid 2-methyladamantyl 2-yl ester, (meth) acrylic-acid 2-methyl-3-hydroxyadamantyl 2-yl ester, (meth) acrylic acid 2-ethyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyl-3-hydroxyadamantyl-2-yl ester, (meth) acrylic acid 2-n-propyl Adamantyl-2-yl ester, (meth) acrylic acid 2-isopropyladamantyl-2-yl ester, (meth) acrylic acid-2-methylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic Acid-2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-8-methyltri Black [5.2.1.0 ^2,6] decan-8-yl ester, (meth) ethyl-8-acrylic acid tricyclo [5.2.1.0 ^2,6] decan-8-yl ester, (Meth) acrylic acid-4-methyltetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl ester, (meth) acrylic acid-4-ethyltetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept-2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tetracyclo [6.2.1 ^3,6.0 0.0 ^2,7 ] dodecane -4-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1- (3-hydroxyadamantan-1-yl) -1-methyl ethyl ester, (meth) acrylic acid 1,1-dicyclohexylethyl ester, (meth) acrylic acid 1,1-di (bicyclo [2.2.1] hept-2-yl) ethyl ester, Meth) acrylic acid 1,1-di (tricyclo [5.2.1.0 ^2,6] decan-8-yl) ethyl ester, (meth) acrylic acid 1,1-di (tetracyclo [6.2.1 ^3,6 .0 ^2,7] dodecane-4-yl) ethyl esters, (meth) acrylic acid 1,1-di (adamantan-1-yl) ethyl ester and the like.

The resin [A] used in the present invention has, in addition to the above repeating unit [1], another repeating unit (hereinafter referred to as “repeating unit [2]”) that does not have a structure that exhibits alkali solubility by the action of an acid. ).

〔各式中、Ｒ^５は、水素原子であり、Ｒ^６は、水素原子又はメトキシ基である。Ａは、単結合又はメチレン基であり、Ｂは、酸素原子又はメチレン基である。ｑは、１〜３の整数であり、ｒは、０又は１である。〕

〔式中、Ｒ^１は、水素原子、メチル基又はトリフルオロメチル基であり、Ｘは、炭素数７〜２０の多環型脂環式炭化水素基である。〕

〔式中、Ｒ^１は、水素原子、メチル基又はトリフルオロメチル基であり、Ｒ^７は、２価の有機基である。〕

〔式中、Ｒ^１は、水素原子、メチル基又はトリフルオロメチル基であり、Ｙは、炭素数１〜３の２価の有機基であり、Ｚは、互いに独立して、単結合又は炭素数１〜３の２価の有機基であり、Ｒ^８は、互いに独立して、水素原子、ヒドロキシル基、シアノ基又は−ＣＯＯＲ^９基（但し、Ｒ^９は、水素原子あるいは炭素数１〜４の直鎖状もしくは分岐状のアルキル基、又は、炭素数３〜２０の脂環式のアルキル基を表す。）である。〕 Although the said repeating unit [2] is not specifically limited, It is represented by the unit containing the lactone structure represented by the following general formula (f-1)-(f-6), and the following general formula (4)-(6). Units.

[In each formula, R ⁵ is a hydrogen atom, and R ⁶ is a hydrogen atom or a methoxy group. A is a single bond or a methylene group, and B is an oxygen atom or a methylene group. q is an integer of 1 to 3, and r is 0 or 1. ]

[Wherein, R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and X represents a polycyclic alicyclic hydrocarbon group having 7 to 20 carbon atoms. ]

[Wherein, R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁷ represents a divalent organic group. ]

[Wherein, R ¹ is a hydrogen atom, a methyl group or a trifluoromethyl group, Y is a divalent organic group having 1 to 3 carbon atoms, and Z is independently a single bond or carbon R ⁸ is a hydrogen atom, a hydroxyl group, a cyano group, or a —COOR ⁹ group (provided that R ⁹ is a hydrogen atom or a carbon number of 1 to 4). Represents a linear or branched alkyl group or an alicyclic alkyl group having 3 to 20 carbon atoms. ]

In the unit containing the lactone structure represented by the general formulas (f-1) to (f-6), the main chain skeleton is not particularly limited, but is preferably a (meth) acrylate structure or α-tri It has a fluoroacrylic ester structure. The repeating unit [2] preferably includes a unit represented by the general formula (f-3).
Therefore, among the monomers forming the units containing the lactone structure represented by the general formulas (f-1) to (f-6), preferred compounds include (meth) acrylic acid-5-oxo-4. -Oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1. 0 ^3,7 ] non-2-yl ester, (meth) acrylic acid-5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 ] dec-2-yl ester, (meth) acrylic Acid-10-methoxycarbonyl-5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 ] non-2-yl ester, (meth) acrylic acid-6-oxo-7-oxa-bicyclo [3.2.1] oct-2-yl Steal, (meth) acrylic acid-4-methoxycarbonyl-6-oxo-7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-7-oxo-8-oxa- Bicyclo [3.3.1] oct-2-yl ester, (meth) acrylic acid-4-methoxycarbonyl-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, ( (Meth) acrylic acid-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-methyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-ethyl-2-oxo Tetrahydropyran-4-yl ester, (meth) acrylic acid-4-propyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-5- Oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2,2-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl Ester, (meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5,5- Dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid -3,3-dimethyl-5-oxotetrahydrofuran - yl methyl ester, and (meth) -4,4-dimethyl-5-oxo-tetrahydrofuran-2-yl methyl ester and acrylic acid.

尚、上記の態様（４ａ）〜（４ｅ）で表される炭化水素基において、炭素原子に２つの水素原子が結合している場合の、水素原子が、炭素数１〜４の直鎖状、分岐状又は環状のアルキル基（メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、２−メチルプロピル基、１−メチルプロピル基、ｔｅｒｔ−ブチル基等）、ヒドロキシル基、シアノ基、カルボキシル基又は炭素数１〜１０のヒドロキシアルキル基で置換されていてもよい。 In the repeating unit represented by the general formula (4), X is a polycyclic alicyclic hydrocarbon group having 7 to 20 carbon atoms, and the following bicyclo [2.2.1] heptane (4a ), Bicyclo [2.2.2] octane (4b), tricyclo [5.2.1.0 ^2,6 ] decane (4c), tetracyclo [6.2.1.1 ^3,6 . And hydrocarbon groups containing an alicyclic ring derived from cycloalkanes such as 0 ^2,7 ] dodecane (4d) and tricyclo [3.3.1.1 ^3,7 ] decane (4e).

In the hydrocarbon groups represented by the above embodiments (4a) to (4e), when two hydrogen atoms are bonded to a carbon atom, the hydrogen atom is a straight chain having 1 to 4 carbon atoms, Branched or cyclic alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, tert-butyl group, etc.), hydroxyl group, cyano Group, a carboxyl group, or a C1-C10 hydroxyalkyl group may be substituted.

Therefore, among the monomers forming the repeating unit represented by the general formula (4), preferred compounds include (meth) acrylic acid 2-bicyclo [2.2.1] heptyl ester, (meth) acrylic. Acid 2-bicyclo [2.2.2] octyl ester, (meth) acrylic acid 8-tricyclo [5.2.1.0 ^2,6 ] decanyl ester, (meth) acrylic acid 9-tetracyclo [6.2 1.1 ^{3, 6} . 0 ^2,7 ] dodecanyl ester, (meth) acrylic acid 1-tricyclo [3.3.1.1 ^3,7 ] decanyl ester, (meth) acrylic acid 2-tricyclo [3.3.1.1 ^{3 , 7} ] decanyl ester and the like.

In the repeating unit represented by the general formula (5), R ⁷ is a divalent organic group. Examples of the divalent organic group include a hydrocarbon group, an alkylene glycol group, and an alkylene ester group. Of these, hydrocarbon groups are preferred, and may be chain-like or cyclic.
Chain hydrocarbon groups include methylene, ethylene, 1,3-propylene, 1,2-propylene and other propylene groups, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octane Methylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonadecamethylene group Methylene group, insalene 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, propylidene group, 2-propylidene group, etc. It includes sums chain hydrocarbon group. The cyclic hydrocarbon group includes a cyclobutylene group such as a 1,3-cyclobutylene group, a cyclopentylene group such as a 1,3-cyclopentylene group, and a cyclohexylene group such as a 1,4-cyclohexylene group. A monocyclic hydrocarbon ring group such as a cycloalkylene group having 3 to 10 carbon atoms such as a cyclooctylene group such as a 1,5-cyclooctylene group; a 1,4-norbornylene group, a 2,5-norbornylene group, etc. Bridged cyclic hydrocarbon ring groups having 4 to 30 carbon atoms such as 2 to 4 cyclic hydrocarbon ring groups such as adamantylene groups such as norbornylene group, 1,5-adamantylene group and 2,6-adamantylene group Etc.

In the case where R ⁷ is a divalent aliphatic cyclic hydrocarbon group, an alkylene group having 1 to 4 carbon atoms as a spacer between the bistrifluoromethyl-hydroxy-methyl group and the aliphatic cyclic hydrocarbon group. Is preferably inserted.
R ⁷ in the general formula (5) is preferably a hydrocarbon group containing a 2,5-norbornylene group, a 1,2-ethylene group, or a propylene group.

  Accordingly, among the monomers forming the repeating unit represented by the general formula (5), preferred compounds include (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2). -Hydroxy-3-propyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1, 1-trifluoro-2-trifluoromethyl-2-hydroxy-5-pentyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) Esters, (meth) acrylic acid 2-{[5- (1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2 1] heptyl} ester.

  In the repeating unit represented by the general formula (6), Y is a divalent organic group having 1 to 3 carbon atoms, and Z is independently a single bond or a divalent group having 1 to 3 carbon atoms. Is an organic group. Examples of these divalent organic groups having 1 to 3 carbon atoms include a methylene group, an ethylene group, and a propylene group.

In the repeating unit represented by the general formula (6), R ⁸ is independently a hydrogen atom, a hydroxyl group, a cyano group, or a —COOR ⁹ group. In the case ^{where R 8} is -COOR ⁹ group where ^{R 9} is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, or an alkyl alicyclic having 3 to 20 carbon atoms It is a group.
Examples of the linear or branched alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, Examples thereof include a tert-butyl group.
The alicyclic alkyl group of said 3 to 20 carbon _{atoms, -C n H 2n-1 (} n is an integer of 3 to 20) represented by a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, A cycloalkyl group (monocyclic alicyclic alkyl group) such as a cycloheptyl group and a cyclooctyl group; a bicyclo [2.2.1] heptyl group, a tricyclo [5.2.1.0 ^2,6 ] decyl group, Tetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecanyl group, polycyclic alicyclic alkyl group such as adamantyl group and the like. In addition, the hydrogen atom in said alicyclic alkyl group may be a group formed by substitution with one or more linear, branched or cyclic alkyl groups.

  Therefore, among the monomers forming the repeating unit represented by the general formula (6), preferred compounds are (meth) acrylic acid 3-hydroxyadamantan-1-ylmethyl ester, (meth) acrylic acid 3, 5-dihydroxyadamantan-1-ylmethyl ester, (meth) acrylic acid 3-hydroxy-5-methyladamantan-1-yl ester, (meth) acrylic acid 3,5-dihydroxy-7-methyladamantan-1-yl ester (Meth) acrylic acid 3-hydroxy-5,7-dimethyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy-5,7-dimethyladamantan-1-ylmethyl ester, and the like.

  The repeating unit [2] may further contain other repeating units other than those described above. Examples of the compound that forms such a repeating unit include (meth) acrylic acid, (meth) acrylic acid ester having a bridged hydrocarbon skeleton, (meth) acrylic acid ester having no bridged hydrocarbon skeleton, Carboxyl group-containing unsaturated carboxylic acid ester having a bridged hydrocarbon skeleton, carboxyl group-containing unsaturated carboxylic acid ester having no bridged hydrocarbon skeleton, and a polyfunctional monomer having a bridged hydrocarbon skeleton And a polyfunctional monomer having no bridged hydrocarbon skeleton.

  Examples of the (meth) acrylic acid ester having a bridged hydrocarbon skeleton include dicyclopentenyl (meth) acrylate and adamantylmethyl (meth) acrylate.

  Examples of (meth) acrylic acid esters having no bridged hydrocarbon skeleton include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and n-butyl (meth) acrylate. , 2-methylpropyl (meth) acrylate, 1-methylpropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate , (Meth) acrylic acid cyclopropyl, (meth) acrylic acid cyclopentyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid 4-methoxycyclohexyl, (meth) acrylic acid 2-cyclopentyloxycarbonylethyl, (meth) acrylic acid 2-Cyclohexyloxycarbonylethyl, (meth) acrylic acid 2 (4-methoxy-cyclohexyl) oxycarbonyl ethyl, and the like.

  Examples of the carboxyl group-containing unsaturated carboxylic acid ester having a bridged hydrocarbon skeleton include carboxynorbornyl (meth) acrylate, carboxytricyclodecanyl (meth) acrylate, and carboxytetracycloundecacate (meth) acrylate. Nil and the like.

  Examples of the carboxyl group-containing unsaturated carboxylic acid ester having no bridged hydrocarbon skeleton include methyl α-hydroxymethyl acrylate, ethyl α-hydroxymethyl acrylate, n-propyl α-hydroxymethyl acrylate, α-hydroxy N-butyl methyl acrylate, (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate, 3-carboxypropyl (meth) acrylate, 4- (meth) acrylic acid 4- Examples thereof include carboxybutyl and 4-carboxycyclohexyl (meth) acrylate.

  Examples of the polyfunctional monomer having a bridged hydrocarbon skeleton include 1,2-adamantanediol di (meth) acrylate, 1,3-adamantanediol di (meth) acrylate, and 1,4-adamantanediol di (meta). ) Acrylate, tricyclodecanyl dimethylol di (meth) acrylate, and the like.

  Polyfunctional monomers that do not have a bridged hydrocarbon skeleton include methylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,6-hexanediol di (Meth) acrylate, 2,5-dimethyl-2,5-hexanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,4 -Bis (2-hydroxypropyl) benzenedi (meth) acrylate, 1,3-bis (2-hydroxypropyl) benzenedi (meth) acrylate and the like.

  Among these, a unit in which a polymerizable unsaturated bond of (meth) acrylic acid ester having a bridged hydrocarbon skeleton is cleaved is preferable.

  Even if the content of the repeating unit [2] constituting the resin [A] is one kind of resin or two kinds or more, each resin is targeted for all resins. When the total amount of repeating units constituting the above, that is, the total of the above repeating units [1] and [2] is 100 mol%, it is 40 mol% or less, preferably 35 mol% or less, more preferably 30 The mol% or less, more preferably 25 mol% or less.

The composition used in the present invention contains, as the resin [A], a resin (copolymer) (hereinafter referred to as “a”) containing the repeating unit [1] at 60 mol% or more and the repeating unit [2] at 40 mol% or less. Resin (A1) ") is preferably used alone or in combination of two or more. As this resin (A1), a particularly preferred resin (A1) is one selected from the embodiments (a) to (d) in which the repeating unit [1] is described in the unit represented by the general formula (2). The above is a resin (copolymer) in which the repeating unit [2] is at least one selected from the above general formulas (f-1) to (f-6).
The composition used in the present invention contains one or more of the above resins (A1) and the repeating unit [1] less than 60 mol% as long as the composition contains 60 mol% or more of the repeating unit [1]. Or a resin [A] comprising at least one resin (copolymer) containing more than 40 mol% of the above repeating unit [2] (hereinafter referred to as “resin (A2)”). Good.

  The weight average molecular weight (hereinafter referred to as “Mw”) in terms of polystyrene by gel permeation chromatography (GPC) of the resin [A] is not particularly limited, but is preferably 1000 to 100,000, more preferably 1000 to 30000, and more preferably. Preferably it is 1000-20000. By being in the said range, it is excellent in developability and heat resistance when forming a resist pattern. The ratio (Mw / Mn) of Mw of the resin [A] and the number average molecular weight (hereinafter referred to as “Mn”) in terms of polystyrene by gel permeation chromatography (GPC) is usually 1 to 5, Preferably it is 1-3.

The resin [A] requires a polymerizable unsaturated monomer corresponding to each repeating unit, using radical polymerization initiators such as hydroperoxides, dialkyl peroxides, diacyl peroxides, and azo compounds. Accordingly, it can be produced by polymerizing in a suitable solvent in the presence of a chain transfer agent. Examples of the solvent include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane and n-decane; cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin and norbornane; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene; ethyl acetate, n-butyl acetate, acetic acid Saturated carboxylic acid esters such as isobutyl and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethanes and diethoxyethanes Is mentioned. These solvents can be used alone or in combination of two or more.
The reaction temperature during the polymerization is usually 40 to 150 ° C, preferably 50 to 120 ° C, and the reaction time is usually 1 to 48 hours, preferably 1 to 24 hours.

In the resin [A], the content of the low molecular weight component derived from the monomer produced during the production of the resin [A] is preferably 0.1% with respect to 100% by mass of the resin [A]. It is not more than mass%, more preferably not more than 0.07 mass%, still more preferably not more than 0.05 mass%. When the content of the low molecular weight component is 0.1% by mass or less, a substance that is eluted when the photoresist film is placed in an immersion exposure liquid such as water during immersion exposure. The amount can be reduced. In addition, it is possible to suppress uneven coating when the composition used in the present invention is applied, and no foreign matter is generated on the surface of the photoresist film during storage of the product including the obtained photoresist film. The occurrence of defects during the formation of the resist pattern can be suppressed.
The monomer-derived low molecular weight component can be analyzed by high performance liquid chromatography (HPLC) of the resin [A], and includes monomers, dimers, trimers, and oligomers. Usually, Mw is 500 or less. It is a component. The components having an Mw of 500 or less are removed by, for example, chemical purification methods such as washing with water and liquid-liquid extraction, or a combination of these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation. can do.
Therefore, the resin [A] used in preparing the composition used in the present invention is preferably as low as possible in the content of impurities such as halogen, metal, etc., including low molecular weight components derived from the above monomers. The sensitivity, resolution, process stability, pattern shape, and the like can be further improved when a resist film is formed and then exposed, developed, and the like.

1-2. Radiation-sensitive acid generator The radiation-sensitive acid generator (hereinafter also referred to as “acid generator [B]”) used in the present invention is applied to the photoresist film by exposing it to radiation (exposure). It is a compound that generates acid. An acid generated from the acid generator [B] by exposure acts on the resin [A] containing the repeating unit [1] having a structure that expresses alkali solubility by the action of an acid. The acid dissociable group is dissociated (the protecting group is eliminated). As a result, the exposed portion of the photoresist film becomes readily soluble in an alkali developer, and a positive resist pattern is formed.

〔式中、Ｒ^１０は、水素原子、フッ素原子、ヒドロキシル基、炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、炭素数１〜１０の直鎖状もしくは分岐状のアルコキシル基、又は、炭素数２〜１１の直鎖状もしくは分岐状のアルコキシカルボニル基であり、Ｒ^１１は、炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、炭素数１〜１０のアルコキシル基、又は、炭素数１〜１０の直鎖状、分岐状、環状のアルカンスルホニル基であり、Ｒ^１２は、互いに独立して、炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、置換基を有してもよいフェニル基あるいは置換基を有してもよいナフチル基であるか、又は、２つのＲ^１２が互いに結合してなり、置換基を有してもよい炭素数２〜１０の２価の基であり、Ｘ⁻は、Ｒ^１３Ｃ_ｎＦ_２ｎＳＯ_３ ⁻、Ｒ^１３ＳＯ_３ ⁻（式中、Ｒ^１３は、フッ素原子、又は、置換基を有してもよい炭素数１〜１２の炭化水素基であり、ｎは、１〜１０の整数である。）、又は、下記一般式（８−１）もしくは（８−２）で表されるアニオンであり、ｊは、０〜１０の整数であり、ｋは、０〜２の整数である。

（各式中、Ｒ^１４は、互いに独立して、フッ素原子を有し、且つ、炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、又は、２つのＲ^１４が互いに結合して、フッ素原子を有し、且つ、炭素数２〜１０の２価の有機基であり、該２価の有機基は置換基を有してもよい。）〕 The acid generator [B] can be used singly or in combination of two or more, but a compound represented by the following general formula (7) (hereinafter referred to as “acid generator 1”). It is preferable to include.

[Wherein, R ¹⁰ represents a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkoxyl group having 1 to 10 carbon atoms, or , A linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms, and R ¹¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, or , A linear, branched, or cyclic alkanesulfonyl group having 1 to 10 carbon atoms, and R ¹² is independently of each other a linear or branched alkyl group having 1 to 10 carbon atoms or a substituent. A phenyl group which may have a substituent or a naphthyl group which may have a substituent, or two R ^{12 s} bonded to each other and may have a substituent. the valence of the group, X ^{- is, R 13} C _{^{F 2n SO 3 -, R 13}} SO 3 - ( ^{wherein, R 13} is fluorine atom, or is an optionally substituted hydrocarbon group having 1 to 12 carbon atoms, n is from 1 to 10 Or an anion represented by the following general formula (8-1) or (8-2), j is an integer of 0 to 10, and k is an integer of 0 to 2. It is.

(In each formula, R ¹⁴ is independently of each other a fluorine atom and a linear or branched alkyl group having 1 to 10 carbon atoms, or two R ¹⁴ are bonded to each other, It is a divalent organic group having 2 to 10 carbon atoms and having a fluorine atom, and the divalent organic group may have a substituent.

In the general formula (7), when R ¹⁰ , R ¹¹ and R ¹² are a linear or branched alkyl group having 1 to 10 carbon atoms, a methyl group, an ethyl group, an n-propyl group, an isopropyl group N-butyl group, 2-methylpropyl group, 1-methylpropyl group, tert-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 tert-butyl group and the like are preferable.

^Further, when ^{R 10} and ^{R 11} is a linear or branched alkoxy group having 1 to 10 carbon atoms, a methoxy group, an ethoxy group, n- propoxy group, isopropoxy group, n- butoxy group, 2- Methylpropoxy group, 1-methylpropoxy group, tert-butoxy group, n-pentyloxy group, neopentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy group, An n-nonyloxy group, an n-decyloxy group, etc. are mentioned. Of these, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, and the like are preferable.

When R ¹⁰ is a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms, a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an isopropoxycarbonyl group, an n-butoxycarbonyl group, 2 -Methylpropoxycarbonyl group, 1-methylpropoxycarbonyl group, tert-butoxycarbonyl group, n-pentyloxycarbonyl group, neopentyloxycarbonyl group, n-hexyloxycarbonyl group, n-heptyloxycarbonyl group, n-octyloxy Examples include carbonyl group, 2-ethylhexyloxycarbonyl group, n-nonyloxycarbonyl group, n-decyloxycarbonyl group and the like. Of these, methoxycarbonyl group, ethoxycarbonyl group, n-butoxycarbonyl group and the like are preferable.

When R ¹¹ is a linear, branched or cyclic alkanesulfonyl group having 1 to 10 carbon atoms, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a tert-butanesulfonyl group Group, n-pentanesulfonyl group, neopentanesulfonyl group, n-hexanesulfonyl group, n-heptanesulfonyl group, n-octanesulfonyl group, 2-ethylhexanesulfonyl group n-nonanesulfonyl group, n-decanesulfonyl group, cyclo A pentanesulfonyl group, a cyclohexanesulfonyl group, etc. are mentioned. Of these, methanesulfonyl group, ethanesulfonyl group, n-propanesulfonyl group, n-butanesulfonyl group, cyclopentanesulfonyl group, cyclohexanesulfonyl group and the like are preferable.

  J is an integer of 0 to 10, preferably 0, 1 or 2.

R ¹² in the general formula (7) may be a phenyl group or a phenyl group having a substituent. In the latter case, o-tolyl group, m-tolyl group, p-tolyl group, 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-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-fluoro And a phenyl group substituted with a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, such as a phenyl group.

In the above phenyl group and alkyl-substituted phenyl group, one or more hydrogen atoms are replaced by a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, or the like. It can also be a substituted group.
Examples of the alkoxyl group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a 2-methylpropoxy group, a 1-methylpropoxy group, a tert-butoxy group, a cyclopentyloxy group, and a cyclohexyloxy group. And a straight-chain, branched or cyclic alkoxyl group having 1 to 20 carbon atoms.
Examples of the alkoxyalkyl group include linear chains having 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 branched or cyclic alkoxyalkyl group.
Examples of the alkoxycarbonyl group include methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group, 2-methylpropoxycarbonyl group, 1-methylpropoxycarbonyl group, tert-butoxycarbonyl. And a linear, branched or cyclic alkoxycarbonyl group having 2 to 21 carbon atoms, such as a group, a cyclopentyloxycarbonyl group, and cyclohexyloxycarbonyl.
Examples of the alkoxycarbonyloxy group include a methoxycarbonyloxy group, an ethoxycarbonyloxy group, an n-propoxycarbonyloxy group, an isopropoxycarbonyloxy group, an n-butoxycarbonyloxy group, a tert-butoxycarbonyloxy group, and a cyclopentyloxycarbonyl. And a straight-chain, branched or cyclic alkoxycarbonyloxy group having 2 to 21 carbon atoms, such as a group and cyclohexyloxycarbonyl.

When R ¹² in the general formula (7) is an optionally substituted phenyl group, a phenyl group, a 4-cyclohexylphenyl group, a 4-tert-butylphenyl group, a 4-methoxyphenyl group, a 4-tert- A butoxyphenyl group and the like are preferable.

Further, R ¹² in the general formula (7) may be a 1-naphthyl group or a 2-naphthyl group, or may be a naphthyl group having a substituent. In the latter case, 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 -Naphtyl 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 1-10 carbon atoms such as dimethyl-1-naphthyl group, 4-ethyl-1-naphthyl group, 1-methyl-2-naphthyl group, 3-methyl-2-naphthyl group, 4-methyl-2-naphthyl group, etc. And a naphthyl group substituted with a linear, branched or cyclic alkyl group.

In the above naphthyl group and alkyl-substituted naphthyl group, one or more hydrogen atoms are replaced by hydroxyl group, carboxyl group, cyano group, nitro group, alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group, alkoxycarbonyloxy group, etc. It can also be a substituted group.
For the above alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group and alkoxycarbonyloxy group, the groups exemplified in the description of the alkyl-substituted phenyl group can be applied.

When R ¹² in the general formula (7) is an optionally substituted naphthyl group, 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-propoxy) A naphthyl) group, a 2- (7-n-butoxynaphthyl) group, and the like are preferable.

Moreover, when two R < ¹² > couple | bonded with the sulfur atom in the said General formula (7) is mutually couple | bonded and is a C2-C10 bivalent group which may have a substituent, said sulfur A 5-membered or 6-membered ring, particularly preferably a 5-membered ring (that is, a tetrahydrothiophene ring) is preferably formed together with the atoms. In the case where the divalent group has a substituent, one or more hydrogen atoms may be substituted with hydroxyl group, carboxyl group, cyano group, nitro group, alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group, alkoxycarbonyloxy group, etc. It can also be a group formed by substitution.
For the above alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group and alkoxycarbonyloxy group, the groups exemplified in the description of the alkyl-substituted phenyl group can be applied.

From the above, as R ¹² in the general formula (7), a methyl group, an ethyl group, a phenyl group, a 4-methoxyphenyl group, a 1-naphthyl group, two R ¹² are bonded to each other, and a tetrahydrothiophene ring is bonded together with a sulfur atom. A divalent group constituting the structure is preferred.
Accordingly, preferred cation sites in the general formula (7) include 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 ON, 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-ethoxyna Chill) tetrahydrothiophenium cation, 2- (7-n- propoxy-naphthyl) tetrahydrothiophenium cation, 2- (7-n- butoxynaphthyl) tetrahydrothiophenium cation, and the like.

X ⁻ in the general formula (7) is R ¹³ C _n F _2n SO ₃ ⁻ , R ¹³ SO ₃ ⁻ , or an anion represented by the general formula (8-1) or (8-2). It is. The —C _n F _2n — group in the case where X ⁻ is R ¹³ C _n F _2n SO ₃ ^— is a perfluoroalkylene group having n carbon atoms, but may be linear or branched. There may be. In addition, n is preferably 1, 2, 4 or 8.
R < ¹³ > is a C1-C12 hydrocarbon group which may have a fluorine atom or a substituent. In the latter case, the hydrocarbon group having 1 to 12 carbon atoms is preferably an alkyl group, a cycloalkyl group, or a bridged alicyclic hydrocarbon group. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, tert-butyl group, n-pentyl group, neopentyl group, n Examples include -hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, cyclohexyl group, norbornyl group, norbornylmethyl group, adamantyl group and the like. When this hydrocarbon group has a substituent, one or more hydrogen atoms may be substituted with a hydroxyl group or the like, and examples thereof include a hydroxynorbornyl group.

Moreover, R < ¹⁴ > in case X < ^- > is an anion represented by the said general formula (8-1) or (8-2) has a mutually independent fluorine atom, and C1-C10 May be a linear or branched alkyl group, or two R ¹⁴ may be bonded to each other to have a fluorine atom and be a divalent organic group having 2 to 10 carbon atoms. In that case, the divalent organic group may have a substituent.
In the general formula (8-1) or (8-2), when R ¹⁴ is a linear or branched alkyl group having 1 to 10 carbon atoms, a trifluoromethyl group, a pentafluoroethyl group, or a heptafluoro group. A propyl group, a nonafluorobutyl group, a dodecafluoropentyl group, a perfluorooctyl group, etc. are mentioned.
When R ¹⁴ is a divalent organic group having 2 to 10 carbon atoms, a tetrafluoroethylene group, a hexafluoropropylene group, an octafluorobutylene group, a decafluoropentylene group, an undecafluorohexylene group, etc. Can be mentioned.

Accordingly, preferred anions X ⁻ in the general formula (7) include trifluoromethanesulfonate anion, perfluoro-n-butanesulfonate anion, perfluoro-n-octanesulfonate anion, 2-bicyclo [2.2.1] hepta. 2-yl-1,1,2,2-tetrafluoroethanesulfonate anion, 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate anion, the following formula (9-1) Anion represented by (9-7).

上記酸発生剤１は、１種単独であるいは２種以上を組み合わせて用いることができる。 Examples of the acid generator 1 include triphenylsulfonium trifluoromethanesulfonate, tri-tert-butylphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium trifluoromethanesulfonate, 1 -(3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium trifluoromethanesulfonate, triphenylsulfonium perfluoro-n-butanesulfonate, Tri-tert-butylphenylsulfonium perfluoro-n-butanesulfonate, 4-cycl Hexylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro- n-butanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, tri-tert-butylphenylsulfonium perfluoro-n- Octanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-octanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium -Fluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro- n-octanesulfonate, triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- ( Bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,1,2,2-tetrafluoroethanesulfonate, 4- Methanesulfonylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxy Phenyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothio Phenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2- (bicyclo [2.2.1] hepta 2′-yl) -1,1-difluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,1-difluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 4-methanesulfonylphenyl -Diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- ( Bicyclo [2.2.1] hepta-2′-yl) -1,1-difluoroethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta- 2′-yl) -1,1-difluoroethanesulfonate, compounds represented by the following formulas B1 to B15, etc. And the like.

The acid generator 1 can be used alone or in combination of two or more.

  Further, a radiation sensitive acid generator other than the acid generator 1 (hereinafter referred to as “other acid generator”) can also be used. For example, an onium salt compound, a halogen-containing compound, a diazoketone compound, a sulfone compound, Examples thereof include 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-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis ( 4-tert-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-tert-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2- 1,2,2,2-tetrafluoroethanesulfonate, cyclohexyl, 2-oxocyclohexyl, methylsulfonium trifluoromethanesulfonate, dicyclohexyl, 2-oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate, etc. Can be mentioned.

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 diazo ketone compound include a 1,3-diketo-2-diazo compound, a diazobenzoquinone compound, a diazonaphthoquinone compound, and the like.
Specific examples of the diazoketone compound include 1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, and 1,2-naphtho of 2,3,4,4′-tetrahydroxybenzophenone. Quinonediazide-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 or 1 , 2-naphthoquinonediazide-5-sulfonic acid ester and the like.

Examples of the sulfone compound include β-ketosulfone compounds, β-sulfonylsulfone compounds, 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 compound 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 acid imide trifluoromethanesulfonate, 1,8-naphthalenedicarboxylic acid imidononafluoro-n-butanesulfonate, 1,8-naphthalenedicarboxylic acid Examples include acid imido perfluoro-n-octane sulfonate.
The other acid generators can be used alone or in combination of two or more.

Among the 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-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis ( 4-tert-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-tert-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1, , 2,2-tetrafluoroethane sulfonate,
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-tetrafluoroethanesulfonylbicyclo [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-tetrafluoroethane sulfonyloxy) succinimide, 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate and the like are preferable.

In the composition used in the present invention , the content of the acid generator [B] is preferably 0.1 to 20 with respect to 100 parts by mass of the resin [A] from the viewpoint of ensuring the sensitivity and developability as a resist. It is 0.5 mass part, More preferably, it is 0.5-10 mass part. If the content of the acid generator [B] is less than 0.1 parts by mass, the sensitivity and developability tend to decrease. On the other hand, if the content exceeds 20 parts by mass, the transparency to radiation decreases, and a rectangular resist It tends to be difficult to obtain a pattern. In addition, when using said acid generator 1 and another acid generator in combination, the usage-amount of another acid generator is 80 mass% normally with respect to 100 mass% of acid generators [B]. Hereinafter, it is preferably 60% by mass or less.

1-3. Nitrogen-containing compound used for the nitrogen-containing compound (hereinafter, also referred to as "nitrogen-containing compound [C]".) Is a nitrogen-containing compound other than the acid generator (B), the acid generator upon exposure [B] It acts as an acid diffusion control agent that controls the diffusion phenomenon of acid in the resist film and suppresses undesired chemical reactions in non-exposed areas. Further, by blending this nitrogen-containing compound [C], the radiation-sensitive resin composition is excellent in storage stability, the resolution as a resist is further improved, and the holding time from exposure to heat treatment after exposure is also provided. Changes in the line width of the resist pattern due to fluctuations in (PED) can be suppressed, and the process stability is extremely excellent.
Examples of the nitrogen-containing compound [C] include tertiary amine compounds, amide group-containing compounds, quaternary ammonium hydroxide compounds, and nitrogen-containing heterocyclic compounds.

  Examples of the tertiary amine compound include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n- Tri (cyclo) alkylamines such as octylamine, cyclohexyldimethylamine, dicyclohexylmethylamine, tricyclohexylamine; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4- Aromatic amines such as methylaniline, 4-nitroaniline, 2,6-dimethylaniline and 2,6-diisopropylaniline; alkanolamines such as triethanolamine and N, N-di (hydroxyethyl) aniline; N, N ', N'-tetramethylethylene Amine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzenetetramethylenediamine, bis (2- Dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether, and the like.

  Examples of the amide group-containing compound include N-tert-butoxycarbonyldi-n-octylamine, N-tert-butoxycarbonyldi-n-nonylamine, N-tert-butoxycarbonyldi-n-decylamine, and N-tert. -Butoxycarbonyldicyclohexylamine, N-tert-butoxycarbonyl-1-adamantylamine, N-tert-butoxycarbonyl-2-adamantylamine, N-tert-butoxycarbonyl-N-methyl-1-adamantylamine, (S)- (-)-1- (tert-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (tert-butoxycarbonyl) -2-pyrrolidinemethanol, N-tert-butoxycarbonyl-4-hydroxy Piperidine, -Tert-butoxycarbonylpyrrolidine, N-tert-butoxycarbonylpiperazine, N, N-di-tert-butoxycarbonyl-1-adamantylamine, N, N-di-tert-butoxycarbonyl-N-methyl-1-adamantylamine N-tert-butoxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-tert-butoxycarbonylhexamethylenediamine, N, N, N′N′-tetra-tert-butoxycarbonylhexamethylenediamine, N, N′-di-tert-butoxycarbonyl-1,7-diaminoheptane, N, N′-di-tert-butoxycarbonyl-1,8-diaminooctane, N, N′-di-tert-butoxycarbonyl- 1,9-diaminononane, N, N′-di tert-butoxycarbonyl-1,10-diaminodecane, N, N′-di-tert-butoxycarbonyl-1,12-diaminododecane, N, N′-di-tert-butoxycarbonyl-4,4′-diaminodiphenylmethane N-tert-butoxycarbonyl group-containing amino compounds such as N-tert-butoxycarbonylbenzimidazole, N-tert-butoxycarbonyl-2-methylbenzimidazole, N-tert-butoxycarbonyl-2-phenylbenzimidazole, etc. It is done.

  Examples of the quaternary ammonium hydroxide compound include tetra-n-propylammonium hydroxide and tetra-n-butylammonium hydroxide.

Examples of the nitrogen-containing heterocyclic compound include pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenyl. Pyridines such as pyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine; piperazines such as piperazine, 1- (2-hydroxyethyl) piperazine, pyrazine, pyrazole , Pyridazine, quinosaline, purine, pyrrolidine, piperidine, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, Imidazole, 4-methylimidazole 1-benzyl-2-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, N-tert-butoxycarbonylbenzimidazole, N-tert-butoxycarbonyl-2-methylbenzimidazole, N -Tert-butoxycarbonyl-2-phenylbenzimidazole and the like.
The said nitrogen-containing compound [C] can be used individually by 1 type or in combination of 2 or more types.

In the composition used in the present invention , the content of the nitrogen-containing compound [C] is preferably less than 10 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the resin [A], from the viewpoint of ensuring high sensitivity as a resist. Is less than 5 parts by weight. However, the lower limit is usually 0.001 part by mass. When the content of the nitrogen-containing compound [C] is too large, the sensitivity as a resist tends to be remarkably lowered. On the other hand, if the content of the nitrogen-containing compound [C] is too small, the pattern shape and dimensional stability as a resist may be lowered depending on the process conditions.

1-4. Solvent The solvent used in the present invention (hereinafter also referred to as “solvent [D]”) preferably dissolves the resin [A], acid generator [B] and nitrogen-containing compound [C]. 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-methyl-2-pentanone, 3,3-dimethyl-2-butanone, 2-heptanone, Linear or branched ketones such as 2-octanone; cyclic ketones such as cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, isophorone; propylene glycol Monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propiate Propylene glycol mono-isopropyl ether acetate, propylene glycol mono-n-butyl ether acetate, propylene glycol mono-isobutyl ether acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol mono-tert-butyl ether acetate, etc. Alkyl ether acetates; methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, n-propyl 2-hydroxypropionate, isopropyl 2-hydroxypropionate, n-butyl 2-hydroxypropionate, isobutyl 2-hydroxypropionate , 2-hydroxypropionic acid sec-butyl, 2-hydroxypropionic acid te alkyl 2-hydroxypropionates such as t-butyl; alkyl 3-alkoxypropionates such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, etc. In addition,

  n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, tert-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 mono Chill 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, diethyl Glycol 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. It is done.

Of these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, γ-butyrolactone and the like are preferable.
The said solvent [D] can be used individually by 1 type or in combination of 2 or more types.

1-5. Additives In the radiation sensitive resin composition used in the present invention , additives such as an alicyclic additive having an acid dissociable group, a surfactant, and a sensitizer can be blended as necessary.

The alicyclic additive having an acid dissociable group is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.
Examples of such alicyclic additives include 1-adamantanecarboxylic acid, 2-adamantanone, tert-butyl 1-adamantanecarboxylate, tert-butoxycarbonylmethyl 1-adamantanecarboxylate, 1-adamantanecarboxylic acid α -Butyrolactone ester, 1,3-adamantane dicarboxylate di-tert-butyl, 1-adamantane acetate tert-butyl, 1-adamantane acetate tert-butoxycarbonylmethyl, 1,3-adamantane diacetate di-tert-butyl, 2, Adamantane derivatives such as 5-dimethyl-2,5-di (adamantylcarbonyloxy) hexane; tert-butyl deoxycholic acid, tert-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid, deoxy Deoxycholic acid esters such as 2-cyclohexyloxyethyl cholic acid, 3-oxocyclohexyl deoxycholic acid, tetrahydropyranyl deoxycholic acid, mevalonolactone ester deoxycholic acid; tert-butyl lithocholic acid, tert-butoxycarbonyl lithocholic acid Lithocholic acid esters such as methyl, lithocholic acid 2-ethoxyethyl, lithocholic acid 2-cyclohexyloxyethyl, lithocholic acid 3-oxocyclohexyl, lithocholic acid tetrahydropyranyl, lithocholic acid mevalonolactone ester; dimethyl adipate, diethyl adipate Alkyl carboxylic acid esters such as dipropyl adipate, di-n-butyl adipate, di-tert-butyl adipate, and 3- [2-hydroxy-2,2-bis ((Trifluoromethyl) ethyl) tetracyclo [4.4.0.12,5.17,10] dodecane and the like. These alicyclic additives can be used alone or in combination of two or more.

The surfactant is a component having an action of improving coatability, 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. In addition to nonionic surfactants such as polyethylene glycol distearate, the following trade names “KP341” (manufactured by Shin-Etsu Chemical Co., Ltd.), “Polyflow No. 75”, “Polyflow No. 95” (above) , Kyoeisha Chemical Co., Ltd.), "F-top EF301", "F-top EF303", "F-top EF352" (above, manufactured by Tochem Products), "Megafax F171", "Megafax F173" ( Greater than Japan (Made by Ki Chemical Industry Co., Ltd.), “Florard FC430”, “Florard FC431” (manufactured by Sumitomo 3M), “Asahi Guard AG710”, “Surflon S-382”, “Surflon SC-101”, “ Examples include Surflon SC-102, Surflon SC-103, Surflon SC-104, Surflon SC-105, Surflon SC-106 (manufactured by Asahi Glass Co., Ltd.). These surfactants can be used singly or in combination of two or more.

The sensitizer absorbs radiation energy and transmits the energy to the acid generator [B], thereby increasing the amount of acid generated. The apparent appearance of the radiation-sensitive resin composition Has the effect of improving the sensitivity.
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 alone or in combination of two or more.

  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. Furthermore, by blending a dye or pigment, the latent image of the exposed area can be visualized, and the influence of halation during exposure can be reduced. By blending an adhesion aid, adhesion to the substrate can be improved. it can.

1-6. Preparation of Composition The composition used in the present invention has a total solid content of resin [A], acid generator [B], nitrogen-containing compound [C], and additives used as necessary. However, it can be prepared by dissolving each of the above components in the solvent [D] so that it is preferably 1 to 50% by mass, more preferably 1 to 25% by mass. After dissolution, for removal of impurities, filtration may be performed using, for example, a filter having a pore size of about 0.2 μm.

2. Method for Forming Resist Pattern As an example of the method for forming a resist pattern of the present invention, the lower layer antireflection of a composite substrate in which a lower layer antireflection film is formed on the surface of a substrate made of an inorganic substance or on a substrate made of an inorganic substance A photoresist film forming step in which the composition of the present invention is applied to the surface of the film to form a photoresist film, and immersion is performed in a state where an immersion exposure liquid is disposed on the surface of the photoresist film. mention may be made of those comprising an exposure step, a developing step of the exposed portions of the photoresist film is removed by a developer.

  As a substrate made of an inorganic substance used in the photoresist film forming step, a metal such as silicon, aluminum, iron, ruthenium, tungsten, titanium, molybdenum, which is not deformed or altered by heat treatment performed as necessary thereafter; A substrate made of stainless steel, aluminum / silicon alloy, aluminum / silicon / copper alloy, tungsten silicide, or the like can be used. A laminated substrate such as a wafer coated with aluminum can also be used. Also, in the subsequent immersion exposure process, if the irradiated radiation may be reflected on the substrate surface, halation and standing waves may occur, and a fine resist pattern may not be accurately reproduced. A composite substrate on which an antireflection film is formed is used. The lower antireflection film can be made of a known organic or inorganic material disclosed in Japanese Patent Application Laid-Open No. 59-93448. The thickness of the lower antireflection film is not particularly limited, but is usually in the range of 10 to 200 nm.

In the photoresist film forming step, the composition used in the present invention is applied to the surface of the substrate or the lower antireflection film of the composite substrate by spin coating, casting coating, roll coating, etc. The solvent is removed by natural drying or heat treatment (hereinafter referred to as “pre-bake”) to form a photoresist film to obtain a substrate with a photoresist film (hereinafter referred to as “laminated substrate”). . The photoresist film may be a single layer or a plurality of layers. The film thickness is usually in the range of 50 to 500 nm.
A schematic diagram of the laminated substrate is as shown in FIG. That is, the laminated substrate 2 in FIG. 2 is provided on a substrate 21 such as a silicon plate, a lower antireflection film 22 provided on one surface of the substrate 21, and a surface of the lower antireflection film 22. And a photoresist film 23.
If necessary, for example, in order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film such as that disclosed in Japanese Patent Laid-Open No. 5-188598 is used. It can be disposed on the surface. This protective film usually has a property that does not cause mixing with the photoresist film, and is dissolved, altered, expanded, etc. by a liquid for immersion exposure that will be contacted in a subsequent immersion exposure process. It has the property of not producing.

In the immersion exposure process, first, an immersion exposure liquid having a refractive index higher than that of air at a wavelength of 193 nm is disposed so that the liquid covers at least the surface of the photoresist film of the laminated substrate. Examples of the immersion exposure liquid include water; fluorine-based inert liquids such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F _7. Usually, water is used. Thereafter, an exposure lens is disposed on the liquid surface so that only one surface is in contact with the immersion exposure liquid. Then, the surface of the photoresist film is irradiated, that is, exposed to radiation such as visible light, ultraviolet light, far ultraviolet light, X-rays, and charged particle beams through a photomask having a mask pattern for forming a desired pattern. . Thereby, the radiation passes through the opening of the photomask, further passes through the exposure lens and the immersion exposure liquid (and the protective film), and reaches the photoresist film.
The radiation is selected depending on the type of acid generator contained in the photoresist film, but far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable. In particular, an ArF excimer laser (wavelength 193 nm) is preferable. The exposure conditions such as the exposure amount are appropriately selected according to the composition of the photoresist film, the type of additive, and the like.

After the liquid immersion exposure step, the laminated substrate is taken out from the liquid for liquid immersion exposure and washed as necessary. When a protective film is formed on the surface of the photoresist film, the protective film may be removed at this time, or after the post-exposure heating described below.
Thereafter, the laminated substrate provided with the exposed photoresist film is heated (hereinafter also referred to as “post-exposure heating (PEB)”) to smoothly dissociate the acid-dissociable groups of the resin contained in the photoresist film. Proceed. The conditions for the post-exposure heating are appropriately selected according to the composition of the photoresist film, the type of additive, and the like, but the temperature is usually 30 to 200 ° C., preferably 50 to 170 ° C. The time is usually 5 to 300 seconds.

  Next, in the development step, the exposed portion of the photoresist film is removed with a developer. This developer is an alkaline solution such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, Triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [ 4.3.0] An aqueous solution (alkaline aqueous solution) in which a compound such as 5-nonene is dissolved can be used. In this case, the solute may be one of the above compounds or two or more. When the developer is an aqueous solution (alkaline aqueous solution) in which the compound is dissolved, the concentration is usually 10% by mass or less. If this concentration is too high, the unexposed area may also be dissolved in the developer.

The developer may contain an organic solvent, a surfactant and the like. Examples of organic solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, 2,6-dimethylcyclohexanone, and the like; methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol , N-butyl alcohol, tert-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, 1,4-hexanedimethylol and other alcohols; tetrahydrofuran, dioxane and other ethers; ethyl acetate, n-acetate -Esters such as butyl and isoamyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonylacetone, dimethylformamide and the like. These organic solvents can be used singly or in combination of two or more.
The amount of the organic solvent used is preferably 100% by volume or less when the alkaline aqueous solution is 100% by volume. If the amount of the organic solvent used exceeds 100% by volume, the developability may be deteriorated, resulting in a large amount of development residue in the exposed area.

  After the development step, a desired positive resist pattern can be obtained by taking out the laminated substrate from the developer, washing and drying. In addition, after baking, you may post-bake as needed.

  As described above, according to the method for forming a resist pattern of the present invention, the photoresist film has high resistance to immersion exposure liquid made of water or the like, and acts efficiently as a chemically amplified resist. Accordingly, a resist pattern having a fine structure such as a line-and-space pattern having a small pitch can be formed. Further, the obtained resist pattern has a high accuracy because the cross-sectional shape is unlikely to be a T-top shape.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the following, parts and% are based on mass unless otherwise specified.

Each measurement and evaluation in each of the following synthesis examples was performed in the following manner.
(1) Mw and Mn
Using a GPC column (2 G2000HXL, 1 G3000HXL and 1 G4000HXL) manufactured by Tosoh Corporation, gel permeation with monodisperse polystyrene as a standard under the conditions of elution solvent tetrahydrofuran, flow rate 1.0 ml / min and column temperature 40 ° C. It was subjected to an association chromatography (GPC) measurement to obtain a weight average molecular weight (Mw) and a number average molecular weight (Mn). Further, the degree of dispersion Mw / Mn was calculated from the measurement results.
(2) Amount of low molecular weight component derived from monomer Using an Intersil ODS-25 μm column (4.6 mmφ × 250 mm) manufactured by GL Sciences, eluent acrylonitrile / 0.1% phosphoric acid aqueous solution, and a flow rate of 1.0 The measurement was performed by high performance liquid chromatography (HPLC) under the condition of milliliter / minute, and the low molecular weight component was quantified.
^{(3) 13} C-NMR analysis of ¹³ C-NMR analysis the polymer, a CDCl ₃ as a measuring solvent was carried out using a Nippon Denshi Co. "JNM-EX270".

1. Production of Resin [A] Synthesis Example 1
The following compound (M-1) 27.95 g (28 mol%), compound (M-2) 13.10 g (16 mol%), and compound (M-3) 58.95 g (56 mol%) -Dissolved in 200 g of butanone, and further 3.69 g of dimethyl 2,2'-azobis (2-methylpropionate) was added to prepare a monomer solution. On the other hand, 100 g of 2-butanone was put into a three-necked flask having a volume of 500 ml, and the inside was purged with nitrogen gas for 30 minutes. After purging with nitrogen, the mixture was heated to 80 ° C. with stirring, and the monomer solution was added dropwise through a dropping funnel over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled to 30 ° C. or lower by water cooling. Subsequently, this polymerization solution was put into 2000 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed on the slurry twice with 400 g of methanol. Thereafter, the product was collected by filtration and dried at 50 ° C. for 17 hours to obtain a white powdery resin (72.1 g, yield 72.1%). As a result of ¹³ C-NMR analysis, the content ratio of each repeating unit derived from the compound (M-1), the compound (M-2) and the compound (M-3) was 29.7 mol% in this resin. , 16.5 mol% and 53.8 mol%, Mw was 4500, and Mw / Mn was 1.67 (hereinafter, this copolymer is referred to as “resin (A-1)”. .). In addition, content of the low molecular weight component derived from the monomer used for superposition | polymerization in this resin (A-1) was 0.02% with respect to 100% of this resin.

Synthesis example 2
The following compound (M-1) 28.24 g (28 mol%), compound (M-4) 12.21 g (16 mol%), and compound (M-3) 59.55 g (56 mol%) 2 -Polymerization was conducted in the same manner as in Synthesis Example 1 except that a monomer solution prepared by dissolving in 200 g of butanone and further adding 3.73 g of 2,2'-azobis (isobutyronitrile) was used. It was. As a result of ¹³ C-NMR analysis, the resulting resin had a content ratio of each repeating unit derived from the compound (M-1), the compound (M-4) and the compound (M-3), 32 respectively. 0.04 mol%, 15.9 mol%, and 52.1 mol% copolymers, and Mw was 4400 and Mw / Mn was 1.64 (hereinafter, this copolymer was referred to as “resin (A- 2) "). In addition, content of the low molecular weight component derived from the monomer used for superposition | polymerization in this resin (A-2) was 0.02% with respect to 100% of this resin.

Synthesis example 3
The following compound (M-1) 53.93 g (50 mol%), compound (M-2) 35.38 g (40 mol%), and compound (M-5) 10.69 g (10 mol%) -In the same manner as in Synthesis Example 1 except that a monomer solution prepared by dissolving in 200 g of butanone and further adding 5.58 g of dimethyl 2,2'-azobis (2-methylpropionate) was used. Polymerization was performed. As a result of ¹³ C-NMR analysis, the resin thus obtained had 52% content of each repeating unit derived from the compound (M-1), the compound (M-2), and the compound (M-5). .2 mol%, 39.2 mol%, and 8.6 mol%, and Mw was 7400 (hereinafter, this copolymer is referred to as “resin (A-3)”).

2. Preparation and Evaluation of Radiation Sensitive Resin Composition Examples 1-6 and Comparative Examples 1-2
The resin [A] obtained above, the following acid generator [B], the nitrogen-containing compound [C], and the solvent [D] are mixed in the proportions shown in Table 1, and the radiation-sensitive resin composition is mixed. I got a thing.
<Acid generator [B]>
(B-1): Triphenylsulfonium nonafluoro-n-butanesulfonate (B-2): 1- (4-n-butoxynaphthyl) tetrahydrothiophenium trifluoromethanesulfonate (B-3): Triphenylsulfonium 2- (Bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate (B-4): 4-cyclohexylphenyl-diphenylsulfonium trifluoromethanesulfonate (B-5) : Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate (B-6): Compound having the following structure

<Nitrogen-containing compound [C]>
(C-1): N-tert-butoxycarbonylpyrrolidine
<Solvent [D]>
(D-1): Propylene glycol monomethyl ether acetate (D-2): γ-butyrolactone (D-3): Cyclohexanone

Next, the following evaluation was performed about the prepared radiation sensitive resin composition. Evaluation items and methods are as follows.
(1) Elution amount (elution amount of elution components)
In the following manner, the elution amount evaluation structure 1 shown in FIG. 1 is prepared, and the acid generator [B] and nitrogen-containing compound [C] eluted in the liquid for immersion exposure (ultra pure water) are quantified, It was confirmed whether the total amount of the eluted components was 5.0 × 10 ⁻¹² mol / (cm ² · sec) or more.
In advance, the surface of the 8-inch silicon plate 31 is subjected to HMDS (hexamethyldisilazane) treatment (100 ° C., 60 seconds) using a resist coating / developing apparatus “CLEAN TRACK ACT8” manufactured by Tokyo Electron Co., Ltd. A silicon rubber sheet 4 (manufactured by Kureha Elastomer Co., Ltd., thickness: 1.0 mm, shape: square with a side of 30 cm) was placed on the central portion of the HMDS treated surface. Next, the hollow portion at the center of the silicon rubber sheet 4 was filled with 10 ml of ultrapure water (5 in FIG. 1) using a hole pipette having a capacity of 10 ml.
On the other hand, a 77 nm-thick antireflection film 22 (“ARC29A”, manufactured by Brewer Science Co., Ltd.) is formed on the surface of the 8-inch silicon plate 21 using the “CLEAN TRACK ACT8”, and then prepared as described above. The resulting radiation-sensitive resin composition was spin-coated on the antireflection film 22 using the above apparatus, and the coating film was baked (PB) at a temperature of 115 ° C. for 60 seconds to form a photoresist coating film 23 (film). A substrate 2 with a photoresist coating was obtained.
Next, the substrate 2 with the photoresist film and the silicon rubber sheet 4 are combined with the ultrapure water in which the surface of the photoresist film 23 of the substrate 2 with the photoresist film is filled in the cut-out portion of the silicon rubber sheet 4. The ultrapure water was brought into close contact with the silicon rubber sheet 4 so as to be in contact with each other, and the elution amount evaluation structure 1 was produced (see FIG. 1).

Thereafter, this state was maintained for 10 seconds. The wafer 3 was removed, and ultrapure water was collected with a glass syringe (with a recovery rate of 95% or more), and this was used as an analysis sample. The acid generator [B] and the nitrogen-containing compound [C] in this analysis sample are LC-MS (liquid chromatograph mass spectrometer, LC part: “SERIES1100” manufactured by AGILENT, MS part: PerSeptive Biosystems, Inc. ("Mariner") manufactured under the following conditions. It quantified with the analytical curve from the peak intensity of each anion part of the detected acid generator [B] and nitrogen-containing compound [C]. Calibration curves were prepared from the peak intensities obtained by measuring under the same conditions using 1 ppb, 10 ppb, and 100 ppb aqueous solutions of each compound, and using this calibration curve, the elution amount of the acid generator [B] was calculated from the peak intensity. And the nitrogen compound [C] elution amount was calculated. And the case where the sum total of the elution amount containing an acid generator [B] and a nitrogen-containing compound [C] was 5.0 × 10 ⁻¹² mol / (cm ² · sec) or more was regarded as “bad”. The case where it was below was set as "good".
[LC conditions]
Column: 1 “CAPCELL PAK MG” (manufactured by Shiseido) Flow rate: 0.2 ml / min Eluent: Water / methanol (3/7) with 0.1% formic acid Column temperature: 35 ° C.

(2) Formation and evaluation of resist pattern By the following method, a substrate with a photoresist coating formed by sequentially laminating a lower antireflection film and a photoresist coating on the surface of a silicon substrate is formed, and a positive resist pattern is formed. Then, the sensitivity and the cross-sectional shape of the pattern were evaluated.
Using a coater and developer device “CLEAN TRACK ACT12” manufactured by Tokyo Electron Co., Ltd., a lower antireflection film 22 (“ARC29A”, manufactured by Brewer Science Co., Ltd.) having a film thickness of 77 nm is formed on the surface of the 12-inch silicon plate 21 and reflected. A wafer with a protective film (hereinafter referred to as “composite substrate”) was obtained.
Thereafter, the surface of the composite substrate is spin-coated with the above-mentioned “CLEAN TRACK ACT12”, and the coating film is baked at 120 ° C. for 60 seconds. By (PB), an unexposed photoresist film 23 (film thickness 150 nm) was formed, and a substrate 2 with a photoresist film was obtained (see FIG. 2).
Next, NA (numerical aperture) 0.85, sigma 0 is applied to the surface of the photoresist film 23 using an ArF excimer laser exposure apparatus “TWIN SCAN XT1250i” manufactured by ASML through a photomask having a mask pattern. The film was exposed under the proof conditions of .93 / 0.69. Thereafter, post-exposure heating (PEB) was performed at a temperature of 115 ° C. for 60 seconds. Then, development was performed at 23 ° C. for 30 seconds with an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38%, followed by washing with water and drying to form a positive resist pattern. At this time, the exposure amount for forming a line-and-space pattern (1L1S) having a line width of 65 nm with a one-to-one line width was defined as the optimum exposure amount, and this optimum exposure amount was defined as the sensitivity. In this measurement, a scanning electron microscope (model “S-9380”, manufactured by Hitachi High-Technologies Corporation) was used.
The cross-sectional shape of the 65 nm line and space pattern was observed with an ultra-high resolution field emission scanning electron microscope (model “S-4800”, manufactured by Hitachi High-Technologies Corporation) and showed a T-top shape. In the case of a rectangular shape, “X” is indicated, and “◯” is indicated.
The above results are also shown in Table 1.

  As is apparent from Table 1, according to Examples 1 to 7, it was found that the amount of the eluate in the ultrapure water that was in contact before immersion exposure was small, and the resulting pattern shape was good.

In an Example, it is a schematic sectional drawing which shows the structure for elution amount evaluation for measuring the quantity of an elution thing. It is a schematic sectional drawing which shows a board | substrate with a photoresist film.

Explanation of symbols

1; Elution amount evaluation structure 2; Substrate with a photoresist coating (laminated substrate)
21; Silicon plate (substrate)
22; Lower antireflection film 23; Photoresist coating 3; Wafer 31; Silicon plate 32; HMDS treatment layer 4; Silicon rubber sheet 5;

Claims (3)

The refractive index at a wavelength of 193nm is interposed between the lens and the photoresist film with high immersion exposure liquid than air, the resist pattern forming method comprising the immersion exposure of radiation to the photoresist film met And
The photoresist radiation-sensitive resin composition used for forming a coating film contains a resin, a photoacid generator, a nitrogen-containing compound, and a solvent,
The resin includes a repeating unit [1] represented by the following general formula (2) having a structure that expresses alkali solubility by the action of an acid,
The resist pattern forming method , wherein the content of the repeating unit [1] is 60 mol% or more based on the total amount of the repeating units constituting the resin.

[Wherein, R ¹ is a hydrogen atom, a methyl group or a trifluoromethyl group, R ³ is the same or different organic group, and two R ³ may form a ring structure. ]
The method for forming a resist pattern according to claim 1, wherein the repeating unit [1] includes a repeating unit represented by the following general formula (1).

[Wherein, R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms. ] The method for forming a resist pattern according to claim 1, wherein the resin further contains a repeating unit having a lactone structure.

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