KR101760141B1 - Radiation-sensitive resin composition and process for forming resist pattern - Google Patents

Abstract

(단, 화학식 1 중에서, R¹은 수소 원자 등을 나타내고, R²는 단결합 등을 나타내며, R³은 3가의 유기기를 나타냄).The present invention provides a radiation sensitive resin composition which is excellent in LWR after development and hardly causes film reduction.
(A) a polymer having repeating units represented by the following formula (1) and an acid dissociable group, (B) a radiation-sensitive acid generator, and (C) a polymer containing a fluorine atom It is characterized by including
≪ Formula 1 >

(Wherein R ¹ represents a hydrogen atom or the like, R ² represents a single bond or the like, and R ³ represents a trivalent organic group).

Description

TECHNICAL FIELD [0001] The present invention relates to a radiation-sensitive resin composition and a method for forming a resist pattern,

The present invention relates to a radiation-sensitive resin composition and a method of forming a resist pattern. More particularly, the present invention relates to a radiation-sensitive resin composition and a method of forming a resist pattern which can form a photoresist film having good line width roughness (LWR) after development and in which film reduction is unlikely to occur.

In the field of micromachining for manufacturing integrated circuit devices, a lithography technique capable of micromachining at a level of 0.10 μm or less (that is, sub-quarter micron level) is desired in order to obtain a higher degree of integration, and a KrF excimer laser ) Or an ArF excimer laser (wavelength: 193 nm).

However, in the field of microfabrication, it is desired to form a finer resist pattern (for example, a fine resist pattern having a line width of about 45 nm), and in order to enable formation of a finer resist pattern, The wavelength is shortened, the numerical aperture (NA) of the lens is increased, and so on. However, there is a problem in that a large amount of new exposure apparatus is required to achieve short wavelength of the light source wavelength. Further, in the case of increasing the numerical aperture of the lens, there is a trade-off relationship between the resolution and the depth of focus, so that even if the resolution can be improved, there is a problem that the depth of focus is reduced.

Therefore, recently, as a lithography technique to solve such a problem, a method called liquid immersion lithography (liquid immersion lithography) has been reported. This method is a method in which a liquid for immersion exposure (for example, pure water, a fluorine-based inactive liquid, etc.) is interposed between the lens and the photoresist film (on the photoresist film) during exposure. According to this method, the exposure light path space previously filled with an inert gas such as air or nitrogen is filled with liquid for immersion exposure having a higher refractive index (n) such as air. Therefore, even when the same exposure light source as the conventional one is used, The same effect as in the case of shortening the wavelength of the light source of the exposure apparatus, that is, high resolution can be obtained. Also, the depth of focus does not decrease.

Therefore, according to such a liquid immersion exposure method, a resist pattern excellent in resolution and excellent in depth of focus can be formed at a low cost by using a lens mounted in an existing apparatus.

Examples of the liquid immersion lithography process include a technique of forming a liquid immersion upper layer film on a photoresist film to protect the photoresist film formed from the radiation sensitive resin composition, followed by liquid immersion lithography (see, for example, Patent Document 1) A method of forming a photoresist film by using a radiation-sensitive resin composition containing a polymer containing a fluorine atom (see, for example, Patent Document 2) has been proposed in order to make the upper layer film unnecessary, , Improvement of the processing capability).

International Patent Publication No. 05/069076 International Patent Publication No. 07/116664

However, when the radiation-sensitive resin composition containing the fluorine-containing polymer as described above is used, there is a problem that the LWR (Line Width Roughness) of the resist pattern after development deteriorates or the film decreases. Therefore, development of a radiation-sensitive resin composition capable of forming a photoresist film with good LWR after development and in which film reduction is unlikely to occur is required.

The present invention has been made to solve the problems of the prior art as described above, and it is an object of the present invention to provide a radiation-sensitive resin composition capable of forming a photoresist film having good LWR after development and hardly causing film reduction, and a resist pattern forming method And to provide the above objects.

As a result of intensive studies to achieve the above object, the present inventors have found that (A) a polymer having a specific repeating unit and an acid dissociable group, (B) a radiation-sensitive acid generator, and (C) a polymer containing a fluorine atom The present inventors have found that the above problems can be attained by using the radiation sensitive resin composition containing the radiation-sensitive resin composition.

According to the present invention, the following radiation-sensitive resin composition and a method of forming a resist pattern are provided.

(1) A radiation-sensitive resin composition comprising (A) a radiation-sensitive resin composition comprising a polymer having a repeating unit represented by the following formula (1) and an acid dissociable group, (B) a radiation-sensitive acid generator, and (C) Composition.

(Wherein R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² represents a single bond, a divalent hydrocarbon group having 1 to 5 carbon atoms, an alkanediyloxy group or an alkanediylcarbonyloxy group, R ³ represents a trivalent organic group)

[2] The radiation-sensitive resin composition according to [1], wherein the repeating unit represented by the formula (1) is a repeating unit represented by the following formula (1-1).

Wherein R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² represents a single bond, a divalent hydrocarbon group having 1 to 5 carbon atoms, an alkanediyloxy group or an alkanediylcarbonyl And R ⁵⁰ represents a group represented by the following formula (a) or a group represented by the following formula (b)

<Formula a>

<Formula b>

(Wherein, in the formula (a), n1 represents an integer of 0 to 2, and in the formula (b), n2 to n5 each independently represent an integer of 0 to 2, are shown the coupling hand bonded to the R ^2, only there are one or more of the carbon atoms constituting a group these groups represented by the group) and (b represented by the formula (a) may be substituted with an oxygen atom, a nitrogen atom or a carbonyl group, and The group represented by the formula (a) and the group represented by the formula (b) may have a substituent)

[3] The radiation-sensitive resin composition according to [2], wherein the repeating unit represented by the formula (1) is a repeating unit represented by the following formula (1-1a).

Wherein R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² represents a single bond, a divalent hydrocarbon group having 1 to 5 carbon atoms, an alkanediyloxy group or an alkanediylcarbonyl And R ⁵¹ represents a group represented by the following formula (a1) or a group represented by the following formula (b1)

<Formula a1>

<Formula b1>

(In the formulas (a1) and (b1), * represents a bonding bond binding to R ² in the formula (1-1a)).

[4] The thermosetting resin composition according to the above [1], wherein the polymer (C) has at least one repeating unit selected from the group consisting of repeating units represented by the following formulas (2-1) to (2-3) Resin composition.

(2-1) to (2-3), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and in the formula (2-1), R ⁹ represents a fluorinated alkyl group having 1 to 30 carbon atoms , of the general formula (2-2), R ⁶ represents a single bond or a (g + 1) represents a divalent connecting group, g is an integer from 1 to 3, the formula (2-3) in a, R ⁷ represents a divalent linking group (2-2) and (2-3), R ⁸ represents a hydrogen atom, an acid dissociable group or an alkali dissociable group, each of R ¹⁰ independently represents a hydrogen atom, a fluorine atom, Fluorinated alkyl group, provided that when all of R &lt; ¹⁰ &gt; is a hydrogen atom, it is not)

[5] The positive resist composition according to any one of [1] to [5], wherein the polymer (C) is at least one repeating unit containing at least one group selected from the group consisting of the following formula (2-4) And the repeating unit represented by the formula (1) is excluded).

(In the formula (2-4), R ¹¹ represents a hydrocarbon group having 1 to 10 carbon atoms substituted with a fluorine atom)

[6] The radiation-sensitive resin composition according to the above [5], wherein the content of the polymer (C) is 0.1 to 40 parts by mass relative to 100 parts by mass of the polymer (A).

[7] A process for producing a photoresist film, comprising the steps of: forming a photoresist film by coating the substrate with a radiation-sensitive resin composition according to any one of [1] to [6] Exposing the photoresist film to radiation through the liquid for immersion lithography, and developing the photoresist film irradiated with the radiation with a developer to form a resist pattern.

The radiation-sensitive resin composition of the present invention exhibits an effect of being able to form a photoresist film having good LWR after development and hardly causing film reduction.

Hereinafter, specific details for carrying out the present invention will be described, but the present invention is not limited to the following embodiments. In other words, it is to be understood that modifications, improvements, and the like are properly applied to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[1] Radiation-sensitive resin composition:

The radiation sensitive resin composition of the present invention is a radiation sensitive resin composition comprising (A) a repeating unit represented by the above-mentioned formula (1) (hereinafter sometimes referred to as "repeating unit (I)") and a polymer having an acid dissociable group (A) polymer "), (B) a radiation-sensitive acid generator (hereinafter sometimes simply referred to as" (B) acid generator "), (C) (Hereinafter sometimes referred to as &quot; (C) polymer &quot;).

In the present specification, the same numbers are used when the same is indicated among &quot; R ^x &quot; in the formula.

[1-1] (A) Polymer:

The polymer (A) has a repeating unit represented by the above formula (1) and an acid dissociable group, and is a component to be a base material in the radiation-sensitive resin composition of the present invention. Here, &quot; substrate &quot; means a component having film forming ability. Such a polymer (A) is one in which an acid-dissociable group is dissociated by the action of an acid to become alkali-soluble, and is alkali-insoluble or alkali-insoluble before the acid dissociable group dissociates. The term &quot; alkali insoluble or alkali-insoluble &quot; in the present specification means that, under alkaline developing conditions employed when a resist pattern is formed from a photoresist film formed using a radiation-sensitive resin composition containing (A) Refers to a property that 50% or more of the initial film thickness of the coating film is left after development when a film having a film thickness of 100 nm is developed using only the (A) polymer in place of the resist film.

[1-1-1a] The repeating unit represented by the formula (1)

Examples of R ¹ in the formula 1 is preferably a hydrogen atom, a methyl group, and trifluoromethyl.

Examples of the divalent hydrocarbon group of 1 to 5 carbon atoms represented by R ² in the general formula (1) include linear or branched divalent hydrocarbon groups of 1 to 5 carbon atoms. Specific examples include -CH ₂ -, an ethylene group, a 1,3-propylene group, a 1,2-propylene group, a 2,2-propylene group, a 1,4- Butylene group and the like.

Examples of the alkanediyl group represented by R ² in the general formula (1) include a group in which an oxygen atom is bonded to a divalent hydrocarbon group having 1 to 5 carbon atoms. Examples of the divalent hydrocarbon group having 1 to 5 carbon atoms include -CH ₂ -, an ethylene group, a 1,3-propylene group, a 1,2-propylene group, a 2,2-propylene group, , A 3-butylene group, and a 1,2-butylene group.

The alkanediylcarbonyloxy group represented by R ² in the general formula (1) includes a group having a carbonyloxy group bonded to a divalent hydrocarbon group having 1 to 5 carbon atoms. Examples of the divalent hydrocarbon group having 1 to 5 carbon atoms include -CH ₂ -, an ethylene group, a 1,3-propylene group, a 1,2-propylene group, a 2,2-propylene group, , A 3-butylene group, and a 1,2-butylene group.

In the formula (1), R ³ represents a trivalent organic group, specifically, a trivalent chain hydrocarbon group, a trivalent group having a cyclic hydrocarbon structure, or a trivalent group having a heterocyclic structure. These groups may be substituted with a hydroxyl group, a carboxyl group, a cyano group or the like.

Examples of the repeating unit represented by the formula (1) include repeating units represented by the above formula (1-1), and among the repeating units represented by the formula (1-1), repeating units represented by the above formula (1-1a) Unit may be mentioned as a preferable example. When the repeating unit represented by the above formula (1-1a) is used, a photoresist film having better LWR after development and less likely to cause film reduction can be formed.

R ⁵⁰ in the formula (1-1) and R ⁵¹ in the formula (1-1a) may be substituted with an oxygen atom, a nitrogen atom or a carbonyl group in one of the carbon atoms constituting these groups And may have a substituent. Examples of the substituent include a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a cyano group, a hydroxyalkyl group having 1 to 10 carbon atoms, and a carboxyl group.

Examples of the repeating unit (I) include repeating units represented by the following formulas (3-1) to (3-21). Among them, from the viewpoint of obtaining a radiation-sensitive resin composition capable of forming a photoresist film which is more excellent in LWR after development and hardly causes film reduction, it is preferable to use a repeating unit represented by the following formula (3-1) A repeating unit represented by the following formula (3-9) is preferable. In the following formulas (3-1) to (3-21), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group.

Among the repeating units represented by the above formulas (3-1) to (3-21), the repeating units represented by formulas (3-1) to (3-16) -1a). &Lt; / RTI &gt; Particularly, the repeating units represented by the above formulas (3-4) to (3-7) are those in which R ⁵⁰ in the above formulas (1-1) and (1-1a) Is a repeating unit corresponding to a substituent group having a substituent. The repeating unit represented by the above formulas (3-11) and (3-12) is a repeating unit corresponding to the case where the group represented by the formula (b) has a substituent, specifically, one of the carbon atoms constituting R ⁵⁰ is An oxygen atom or a nitrogen atom. The repeating unit represented by the above formulas (3-13) to (3-16) is a repeating unit corresponding to the case where the group represented by the formula (b) has a substituent, specifically, one of the carbon atoms constituting R ⁵⁰ An oxygen atom, a nitrogen atom or a carbonyl group, and further has a substituent.

The monomer for forming the recurring unit (I) can be synthesized by a conventionally known method, and specifically, it can be synthesized by the method described in Tetrahedron Letters, Vol. 27, No. 32 p. 3741 (1986), Organic Letters, Vol. 4, No. 15, p. 2561 (2002), and the like.

[1-1-1b] Other repeating units (a):

The polymer (A) may have other repeating units (a) in addition to the repeating units represented by the above formula (1). Examples of the other repeating units (a) include the following repeating units (II) to (VI).

[1-1-1b-1] Repeating unit (II):

Examples of the repeating unit (II) include repeating units represented by the following formulas (4-1) to (4-7).

(4-1), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ¹² to R ¹⁴ independently represent a linear or branched alkyl group having 1 to 4 carbon atoms, And R &lt; ¹³ &gt; and R &lt; ¹⁴ &gt; may be bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof)

In formulas (4-2) to (4-7), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group. In the formula (4-2), R ¹⁵ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and p represents an integer of 1 to 3. In the above formulas (4-5) and (4-6), R ¹⁶ independently represents a hydrogen atom or a methoxy group. In the formulas (4-3) and (4-4), R ¹⁷ independently represents a single bond or -CH ₂ -, and each of m independently represents 0 or 1. In the formulas (4-4) and (4-6), R ¹⁸ represents each independently an oxygen atom or -CH ₂ -.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ¹² to R ¹⁴ in the formula (4-1) include a methyl group, an ethyl group, a n-propyl group, an i-propyl group, 1-methylpropyl group, and t-butyl group.

A monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ¹² to R ¹⁴ in the formula (4-1) and a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms formed together with the carbon atoms to which R ¹³ and R ¹⁴ are bonded to each other Examples of the divalent alicyclic hydrocarbon groups of 1 to 20 include bridged skeletons such as adamantane skeleton, norbornane skeleton, tricyclodecane skeleton and tetracyclododecane skeleton, and cyclic butane, cyclopentane , A group having a cycloalkane skeleton such as cyclohexane, cycloheptane, and cyclooctane; These groups may be linear or branched having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, i-propyl, n-butyl, And a group having an alicyclic skeleton such as a group substituted with one or more of branched or cyclic alkyl groups.

Of these alicyclic hydrocarbon groups, those having an adamantane skeleton, those having a bicyclo [2.2.1] heptane skeleton, those having a cyclopentyl skeleton, those having a cyclohexyl skeleton, those having a cycloheptyl skeleton, Octyl skeleton.

Specific examples of the "-CR ¹² R ¹³ R ¹⁴ " in the formula (4-1) include a t-butyl group, a 1-n- (1-ethyl- (1,1-dimethyl) propyl group, 1-n- (1,1-dimethyl) butyl group, (1-ethyl) cyclopentyl group, 1- (1-methylpentyl) cyclopentyl group, 1- (1-ethyl) cyclohexyl group, 1- (1-propyl) cyclopentyl group, 1- 1-methyl-1- (2-norbornyl)} ethyl group, 1- (1-propyl) cyclohexyl group, 1- (2-methyl) norbornyl group, 2- (2-ethyl) norbornyl, 2- 2- (2-ethyl) tetracyclodecanyl group, a 2- (2-methylpropyl) norbornyl group, 2- (2-n-propyl) tetracyclodecanyl , 2- (2-ethyl) adamantyl group, 2- (2-n-propyl) adamantyl group, 2- Examples of the group containing the alicyclic ring include methyl, ethyl, n-propyl, i-propyl, n-butyl, 2-methylpropyl, Branched or cyclic alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl and t-butyl.

Examples of the monomer for forming the repeating unit (II) include (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-methyl-3-hydroxyadamantyl- Ethyl methacrylate, 2-ethyladamantyl-2-yl methacrylate, 2-ethyl-3-hydroxyadamantyl-2-yl methacrylate, 2-n-propyladamantyl (meth) 2-yl ester, (meth) acrylic acid 2-isopropyladamantyl-2-yl ester, (meth) acrylic acid 2-methylbicyclo [2.2.1] hept- (Meth) acrylate-8-methyltricyclo [5.2.1.0 ^2,6 ] dec-8-yl ester, (meth) acrylate-8-ethyl Tricyclo [5.2.1.0 ^2,6 ] dec-8-yl ester,

(Meth) acrylic acid-4-methyltetracyclo [6.2.1 ^3,6 .0 ^2,7 ] dodec-4-yl ester, (meth) acrylic acid-4-ethyltetracyclo [6.2.1 ^3,6 .0 ^2,7 ] dodec-4-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept- .1.0 ^2,6] dec-8-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tetracyclo [6.2.1 ^3,6 .0 ^2,7] dodec-4-yl) -1 (Meth) acrylate, 1- (3-hydroxyadamantan-1-yl) -1-methyl (meth) (Meth) acrylate, 1,1-di (bicyclo [2.2.1] hept-2-yl) ethyl ester of (meth) acrylic acid, Di (tricyclo [5.2.1.0 ^2,6 ] dec-8-yl) ethyl ester, (meth) acrylic acid 1,1-di (tetracyclo [6.2.1 ^3,6 .0 ^2,7 ] dodec Yl) ethyl ester, (meth) acrylic acid 1,1- (Meth) acrylate, 1-methyl-1-cyclopentyl (meth) acrylate, 1-ethyl-1-cyclopentyl Cyclohexyl ester, 1-ethyl-1-cyclohexyl (meth) acrylate, and the like.

Among these monomers, (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylate 2-ethyladamantyl- Hept-2-yl ester, (meth) acrylic acid 2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept- 1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1-methyl-1-cyclopentyl ester, 1-cyclohexyl (meth) acrylate, 1-methyl-1-cyclohexyl (meth) acrylate and 1-ethyl-1-cyclohexyl (meth) acrylate are preferable.

Examples of the alkyl group which may have a substituent and have 1 to 4 carbon atoms and represented by R ¹⁵ in the formula (4-2) include methyl, ethyl, n-propyl, i-propyl, Group, a 1-methylpropyl group, and a t-butyl group.

The content of the repeating unit (II) is preferably 15 to 85 mol%, more preferably 25 to 75 mol%, and more preferably 35 to 60 mol%, based on 100 mol% of the total repeating units of the polymer (A) % Is particularly preferable. If the content is less than 15 mol%, the contrast after dissolution (that is, the portion dissolved in the developing solution and the contrast of the portion not dissolving) is impaired and the pattern shape is lowered Can not be obtained). On the other hand, if it is more than 85 mol%, adhesion with the substrate can not be sufficiently obtained, and the obtained resist pattern may peel off from the substrate.

[1-1-1b-2] Repeating unit (III):

The repeating unit (III) in the other repeating unit (a) is a repeating unit derived from the monomer shown below. Examples of the monomer include (meth) acrylic acid-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylate- 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] deck - 2-yl ester, (meth) acrylate-10-methoxycarbonyl-5-oxo-4-oxa- tricyclo [5.2.1.0 ^3,8 ] non- -7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-4-methoxycarbonyl- (Meth) acrylate-7-oxo-8-oxa-bicyclo [3.3.1] oct- Bicyclo [3.3.1] oct-2-yl ester,

(Meth) acrylate, 4-methyl-2-oxotetrahydropyran-4-yl (meth) acrylate, 4-ethyl (Meth) acrylic acid-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4-propyl- (Meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2- (Meth) acrylate-4,4-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylate- 3-yl ester, (meth) acrylic acid 2-oxotetrahydrofuran-3-yl ester, (meth) acrylate-5-oxotetrahydrofuran- Dime 5 can be an oxo-tetrahydro-furan-2-ylmethyl ester, (meth) acrylic acid-4,4-dimethyl-5-oxo-tetrahydro-furan-2-ylmethyl esters and the like.

The content of the repeating unit (III) is preferably 10 to 50 mol%, more preferably 20 to 40 mol%, based on 100 mol% of the total repeating units of the (A) polymer. If the content is less than 10 mol%, the adhesion with the substrate becomes insufficient and the pattern may peel off. On the other hand, if it exceeds 50 mol%, the solubility in an alkali developing solution becomes insufficient, and the development defects may increase.

[1-1-1b-3] Repeating unit (IV):

As the repeating unit (IV) in the other repeating unit (a), there may be mentioned a repeating unit having an alicyclic hydrocarbon group.

Examples of the repeating unit having an alicyclic hydrocarbon group include repeating units represented by the following formula (5).

(Wherein R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹⁹ represents an alicyclic hydrocarbon group having 4 to 20 carbon atoms)

Examples of the alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ¹⁹ in formula (5) include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, [5. 1] ^2,6 ] decane, tetracyclo [6.17 ^3,6 .0 ^2,7 ] dodecane, and tricyclo [3.3.1.1 ^3,7 ] decane. And a hydrocarbon group.

These cycloalkane-derived alicyclic rings may have a substituent, and examples thereof include a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2- Branched or cyclic alkyl group of 1 to 4 carbon atoms such as methyl, ethyl, propyl, butyl, and the like. These are not limited to those substituted by the alkyl group, but may be substituted with a hydroxyl group, a cyano group, a hydroxyalkyl group having 1 to 10 carbon atoms, a carboxyl group, and oxygen.

Examples of the monomer for forming the repeating unit (IV) include (meth) acrylic acid-bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid- bicyclo [2.2.2] oct- Esters, (meth) acrylic acid-tricyclo [5.2.1.0 ^2,6 ] dec-7-yl ester, (meth) acrylic acid-tetracyclo [6.17 ^3,6 .0 ^2,7 ] dodeca- (Meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] dec-1-yl ester, and (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] dec-2-yl ester.

The content of the repeating unit (IV) is preferably 30 mol% or less, and more preferably 25 mol% or less, when the total repeating units of the (A) polymer is 100 mol%. If the content is more than 30 mol%, the resist pattern shape may deteriorate or the resolution may deteriorate.

[1-1-1b-4] Repeating unit (V):

As the repeating unit (V) in the other repeating unit (a), there may be mentioned a repeating unit represented by the following formula (6).

(In the formula (6), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ²⁰ represents a divalent organic group)

The divalent organic group represented by R ²⁰ in Chemical Formula 6 is preferably a divalent hydrocarbon group, more preferably a chain or cyclic hydrocarbon group, and may be an alkylene glycol group or an alkylene ester group.

Specific examples of the divalent organic group represented by R ²⁰ include -CH ₂ -, a propylene group such as an ethylene group, a 1,3-propylene group or a 1,2-propylene group, a tetramethylene group, a pentamethylene group, , Heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene Propylene group, a 2-methyl-1, 3-propylene group, a 2-methyl-1,2-propylene group, a 1- Methylene-1,4-butylene group, methylidene group, ethylidene group, propylidene group or 2-propylidene group, a saturated hydrocarbon group such as 1,3-cyclobutyl Cyclopentylene group such as 1,3-cyclopentylene group, cyclohexylene group such as 1,4-cyclohexylene group, 1,5-cyclohexylene group such as 1,4-cyclohexylene group, Norbornylene groups such as a 1,4-norbornylene group and a 2,5-norbornylene group, monovalent hydrocarbon groups such as a 1,4-cyclohexylene group such as a 1,4-cyclohexylene group, And a 2- to 4-carbon hydrocarbon hydrocarbon group having 4 to 30 carbon atoms, such as adamantylene group such as 5-adamantylene group and 2,6-adamantylene group, and the like.

When R ²⁰ includes a bivalent aliphatic cyclic hydrocarbon group, it is preferable to dispose an alkylene group having 1 to 4 carbon atoms as a spacer between the bistrifluoromethyl-hydroxy-methyl group and the bivalent aliphatic cyclic hydrocarbon group Do. The divalent organic group represented by R ²⁰ is preferably a hydrocarbon group containing a 2,5-norbornylene group, a 1,2-ethylene group or a propylene group.

Examples of the monomer for forming the repeating unit (V) include (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy- Acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (Meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, (meth) acrylic acid (Meth) acrylate, 2 - {[5- (1 ', 1', 1'-trifluoro-2'-trifluoromethyl-2'-hydroxy) propyl] bicyclo [2.2.1] heptyl} Propyl] tetracyclo [6.17 ^3,6 .0 ^2,7 ] thiophene-2-carboxylic acid ethyl ester was added to a solution of 3 - {[8- (1 ', 1' Dodecyl} esters, and the like.

The content of the repeating unit (V) is preferably 30 mol% or less, more preferably 25 mol% or less, when the total repeating units of the (A) polymer is 100 mol%. If the content is more than 30 mol%, the formed photoresist film may be easily swelled by the alkali developing solution.

[1-1-1b-5] Repeating unit (VI):

Examples of the repeating unit (VI) in the other repeating unit (a) include repeating units derived from an aromatic compound.

Examples of the monomer for forming a repeating unit derived from an aromatic compound include styrene,? -Methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-methoxystyrene, Methoxystyrene, 4-methoxystyrene, 4- (2-t-butoxycarbonylethyloxy) styrene, 2-hydroxystyrene, 3-hydroxystyrene, 4-hydroxystyrene, 3-hydroxystyrene, 4-methyl-3-hydroxystyrene, 5-methyl-3-hydroxystyrene, 3-hydroxy- 4-hydroxystyrene, 3,4-dihydroxystyrene, 2,4,6-trihydroxystyrene, 4-t-butoxystyrene, 4- (2-ethyl-2-propoxy) -? - methylstyrene, 4- (1-ethoxy-2-propoxy) styrene, 4- Methoxy styrene, 4- (1-ethoxyethoxy) -? - methylstyrene, phenyl (meth) acrylate, (meth) (Meth) acrylates such as benzyl, acenaphthylene, 5-hydroxyacenaphthylene, 1-vinylnaphthalene, 2-vinylnaphthalene, 2-hydroxy- (Meth) acrylate, 1-naphthylmethyl (meth) acrylate, 1-anthryl (meth) acrylate, 2-anthryl (Meth) acrylate, 1-vinylpyrrene, and the like.

 The content of the repeating unit (VI) is preferably 40 mol% or less, and more preferably 30 mol% or less, when the total repeating units (A) of the polymer is 100 mol%. If the content is more than 40 mol%, the transmittance of the radiation in the formed photoresist film becomes low, and there is a possibility that the pattern profile will deteriorate (the pattern shape after development will not become a rectangular shape).

Each of the repeating units (II) to (VI) may be contained singly or in combination of two or more.

[1-1-2] Acid dissociation:

The acid dissociable group means a group obtained by substituting a hydrogen atom in a polar functional group such as a hydroxyl group or a carboxyl group, and means a group dissociated in the presence of an acid. Specific examples of such acid dissociable groups include t-butoxycarbonyl group, tetrahydropyranyl group, tetrahydrofuranyl group, (thiotetrahydropyranylsulfanyl) methyl group, (thiotetrahydrofuranylsulfanyl) methyl group, alkoxy- Alkylsulfanyl-substituted methyl group and the like. The alkoxyl group (substituent) in the alkoxy-substituted methyl group includes, for example, an alkoxyl group having 1 to 4 carbon atoms. The alkyl group (substituent) in the alkylsulfanyl-substituted methyl group includes, for example, an alkyl group having 1 to 4 carbon atoms.

The acid dissociable group includes a group represented by the formula: -C (R) ₃ . The three Rs independently represent a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a group derived therefrom, or any two Rs may be bonded to each other A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a group derived therefrom together with the carbon atoms to which they are bonded and the remaining one R is a linear or branched alkyl group having 1 to 4 carbon atoms, 4 to 20 monovalent alicyclic hydrocarbon groups or groups derived therefrom.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R in the group represented by the formula: -C (R) ₃ include methyl, ethyl, n-propyl, -Butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R in the group represented by the formula: -C (R) ₃ include norbornane, tricyclodecane, tetracyclododecane, adamantane And groups containing an alicyclic ring derived from cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane and the like. Examples of the group derived from the alicyclic hydrocarbon group include a monovalent alicyclic hydrocarbon group as described above such as a methyl group, an ethyl group, a n-propyl group, an i-propyl group, an n-butyl group, Branched or cyclic alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl and t-butyl.

Among them, the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R is an alicyclic hydrocarbon group derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane, A hydrocarbon group, or a group in which the alicyclic hydrocarbon group is substituted with an alkyl group.

Any two R's represented by R in the group represented by the chemical formula &quot; -C (R) ₃ &quot; are bonded to each other to form a carbon number (carbon atom bonded to the oxygen atom) Examples of the bivalent alicyclic hydrocarbon group of 4 to 20 include monocyclic hydrocarbon groups such as cyclobutylene group, cyclopentylene group, cyclohexylene group and cyclooctylene group, norbornylene group, tricyclodecanylene group, tetracyclo A polycyclic hydrocarbon group such as a decanylene group, and a crosslinked polycyclic hydrocarbon group such as an adamantylene group.

Any two R's represented by R in the group represented by the formula &quot; -C (R) ₃ &quot; are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms The above-mentioned divalent alicyclic hydrocarbon group may be substituted with a substituent such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, Butyl and the like, or groups substituted by one or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms, and the like.

Among them, a monocyclic hydrocarbon group such as a cyclopentylene group, a cyclohexylene group and the like, or a group in which the divalent alicyclic hydrocarbon group (monocyclic hydrocarbon group) is substituted with an alkyl group is preferable.

Specific examples of the group represented by the formula "-C (R) ₃ " include a t-butyl group, a 1-n- (1-ethyl- Propyl group, 1-n-butyl (1-methylpropyl) group, (1-ethyl) cyclopentyl group, 1- (1-methylpropyl) cyclopentyl group, 1- 1- (1-ethyl) cyclohexyl group, 1- (1-propyl) cyclopentyl group, 1- 1- (1-propyl) cyclohexyl group, 1- {1-methyl-1- (2-norbornyl)} ethyl group, 1- { (2-methyl) norbornyl group, 2- (2-ethyl) norbornyl group, 2- , A 2- (2-ethyl) tetracyclodecanyl group, a 2- (2-methylpropyl) norbornyl group, , 2- (2-n-propyl) tetracycline 1- (1-ethyl) adamantyl group, 1- (1-n-propyl) adamantyl group, 2- (1-i-propyl) adamantyl group, or a group containing these alicyclic rings, for example, a methyl group, ethyl group, n-propyl group, i- Branched or cyclic alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, 1-methylpropyl, and t-butyl.

Among these acid dissociable groups, a group represented by the formula: -C (R) ₃ , a t-butoxycarbonyl group, and an alkoxy-substituted methyl group are preferable.

[1-1-3] Content of fluorine atom:

The polymer (A) may or may not contain a fluorine atom, but when it contains a fluorine atom, the content of the fluorine atom in the polymer (C) is smaller than the content of the fluorine atom in the polymer. The content of fluorine atoms in the polymer (A) is usually less than 5% by mass, preferably 0 to 4.9% by mass, more preferably 0 to 4.0% by mass, based on 100% by mass of the total amount of the polymer (A) Is more preferable. When the content of fluorine atoms in the polymer (A) is smaller than that of the polymer (C), the polymer (C) tends to be localized on the surface layer of the photoresist film. Therefore, the water repellency of the surface layer portion of the formed photoresist film can be enhanced, and a photoresist film having good water repellency can be formed without separately forming a liquid immersion upper layer film during liquid immersion exposure. The difference in the content of fluorine atoms in the polymer (A) and the polymer (C) is preferably 1% by mass or more. When the difference is 1% by mass or more, the polymer (C) tends to be localized on the surface layer of the photoresist film.

In addition to the (A) polymer, a radiation-sensitive resin composition capable of forming a photoresist film particularly suitable for immersion exposure can be obtained by incorporating a polymer (C) described below. Specifically, when the polymer (A) contains a fluorine atom, as described above, the content of fluorine atoms in the polymer (A) is smaller than the content of fluorine atoms in the polymer (C). When the content of fluorine atoms is smaller in the polymer (A) than in the polymer (C), the distribution of the polymer (C) on the surface of the photoresist film due to the oil repellency of the polymer (C) There is a tendency to increase. That is, the (C) polymer is localized on the surface layer of the photoresist film (on the side where the liquid for immersion exposure is arranged). Therefore, it is not necessary to separately form an upper layer film for the purpose of blocking the photoresist film and the immersion medium, and it can be suitably used for the immersion exposure method. Here, the content of fluorine atoms in the present specification is a value measured by ¹³ C-NMR.

The weight average molecular weight (Mw) of the polymer (A) by the gel permeation chromatography (GPC) method is not particularly limited, but is preferably 1,000 to 100,000, more preferably 1,000 to 30,000, and particularly preferably 1,000 to 20,000 desirable. If the Mw is less than 1,000, the heat resistance of the formed photoresist film may be lowered. On the other hand, if it exceeds 100,000, there is a fear that the developed property of the formed photoresist film is lowered. The ratio (Mw / Mn) of Mw to number average molecular weight (Mn) by the GPC method is usually 1 to 5, preferably 1 to 3.

The content ratio of the low molecular weight component derived from a monomer used in producing the polymer (A) in the polymer (A) in terms of solid content is preferably 0.1 mass% or less when the total amount of the polymer (A) is 100 mass% By mass, more preferably 0.07% by mass or less, and particularly preferably 0.05% by mass or less. When the content ratio is 0.1% by mass or less, the amount of the eluted material that is eluted into the immersion exposure liquid at the time of immersion exposure can be reduced. In addition, it is possible to prevent the generation of foreign matter at the time of storage, and to prevent occurrence of uneven application at the time of coating, so that occurrence of defects can be sufficiently suppressed at the time of forming a resist pattern.

The low molecular weight component derived from the monomer is a component having a Mw of 500 or less, and examples thereof include monomers, dimers, trimers, oligomers and the like. Examples of the method for removing components having a Mw of 500 or less (that is, the method for purifying the (A) polymer) include chemical purification methods such as washing with water and liquid extraction, and chemical purification methods such as ultrafiltration and centrifugation And a combination method. Further, the low molecular weight component derived from the monomer (A) in the polymer can be detected by high performance liquid chromatography (HPLC).

Further, the polymer (A) preferably has a smaller content of impurities such as halogen and metal. When the content of the impurity is small, the sensitivity, resolution, and process stability of the formed photoresist film can be further improved, and a favorable resist pattern shape can be obtained.

The polymer (A) may be obtained by copolymerizing a monomer (polymerizable unsaturated monomer) for forming each of the repeating units described above with a radical polymerization initiator such as hydroperoxides, dialkyl peroxides, diacyl peroxides, And, if necessary, in the presence of a chain transfer agent, in a suitable solvent.

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

The reaction temperature in the polymerization is usually 40 to 150 占 폚, preferably 50 to 120 占 폚. The reaction time is usually 1 to 48 hours, preferably 1 to 24 hours.

[1-2] (B) Radiation-sensitive acid generator:

(B) a radiation-sensitive acid generator generates an acid by irradiation of light such as radiation (hereinafter sometimes referred to as &quot; exposure &quot;). The acid-dissociable group present in the polymer (A) is dissociated from the polymer (A) by the action of an acid generated from the acid generator (B) by exposure to light. The polymer (A) in which the acid dissociable group is dissociated becomes alkali soluble. That is, the exposed portion of the photoresist film becomes easy to dissolve in an alkali developing solution. Therefore, a positive resist pattern can be formed by developing with an alkali developer. Examples of the acid generator (B) include the compounds described in paragraphs [0080] to [0113] of JP-A No. 2009-134088.

The acid generator (B) may be used alone or in combination of two or more.

The content of the acid generator (B) is preferably 0.1 to 30 parts by mass, more preferably 2 to 27 parts by mass, and particularly preferably 5 to 25 parts by mass with respect to 100 parts by mass of the (A) polymer. When the content is less than 0.1 part by mass, the sensitivity and resolution of the formed photoresist film may decrease. On the other hand, if it is more than 30 parts by mass, the coating property and the pattern shape of the formed photoresist film may be deteriorated.

[1-3] (C) Polymer:

The polymer (C) is a component contained as a polymer additive in the radiation-sensitive resin composition of the present invention, and is a polymer containing fluorine atoms. By including such a polymer, the water repellency of the formed photoresist film is improved, and there is an advantage that the liquid immersion upper layer film is not required to be formed in the liquid immersion exposure process. Also, by including the (A) polymer and the (C) polymer, (C) the polymer is localized on the surface layer of the photoresist film, and good water repellency is obtained.

As described above, the (C) polymer is not particularly limited as long as it contains a fluorine atom in the molecule, but it is also possible to use a repeating unit represented by the following formula (2-1) (hereinafter referred to as &quot; (Hereinafter sometimes referred to as a "repeating unit (2-2)") and a repeating unit represented by the following formula (2-3) (Hereinafter sometimes referred to as &quot; repeating unit (2-3) &quot;). By having these repeating units, it is possible to suppress the dissolution of the acid generator, the acid diffusion controller, and the like in the photoresist film into the immersion exposure liquid. Further, since the receding contact angle of the photoresist film and the immersion exposure liquid is improved (increased), water droplets derived from the immersion exposure liquid are hardly left on the photoresist film, thereby suppressing the occurrence of defects due to immersion exposure can do.

(2-1) to (2-3), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and in the formula (2-1), R ⁹ represents a fluorinated alkyl group having 1 to 30 carbon atoms , of the general formula (2-2), R ⁶ represents a single bond or a (g + 1) represents a divalent connecting group, g is an integer from 1 to 3, the formula (2-3) in a, R ⁷ represents a divalent linking group (2-2) and (2-3), R ⁸ represents a hydrogen atom, an acid dissociable group or an alkali dissociable group, each of R ¹⁰ independently represents a hydrogen atom, a fluorine atom, Fluorinated alkyl group, provided that when all of R &lt; ¹⁰ &gt; is a hydrogen atom, it is not)

[1-3-1] Repeating unit represented by the formula (2-1):

Examples of the lower alkyl group represented by R ¹ in the formula (2-1) include a methyl group and the like. Examples of the halogenated lower alkyl group represented by R ¹ in the formula (2-1) include a trifluoromethyl group and the like.

Examples of the fluorinated alkyl group having 1 to 30 carbon atoms represented by R ⁹ in the formula (2-1) include a linear or branched alkyl group having 1 to 6 carbon atoms substituted with at least one fluorine atom, a carbon number substituted with at least one fluorine atom 4 to 20 monovalent alicyclic hydrocarbon groups or groups derived therefrom.

Examples of the linear or branched alkyl group having 1 to 6 carbon atoms substituted with at least one fluorine atom include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, (2-methylbutyl) group, 1- (3-methylbutyl) group, 2- (2- Methylbutyl) group, a 2- (3-methylbutyl) group, a neopentyl group, a 1-hexyl group, a 2-hexyl group, Pentyl) group, a 1- (4-methylpentyl) group, a 2- (2-methylpentyl) group, Pentyl) group, a 3- (3-methylpentyl) group, and the like, or a perfluoroalkyl group of a linear or branched alkyl group.

Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms substituted with at least one fluorine atom or a group derived therefrom include a cyclopentyl group, a cyclopentylmethyl group, a 1- (1-cyclopentylethyl) group, (1-cyclohexylethyl) group, a cycloheptyl group, a cycloheptylmethyl group, a cyclohexylmethyl group, a cyclohexylmethyl group, a cyclohexylmethyl group, a cyclohexylmethyl group, Partially fluorinated or perfluoroalkyl groups of alicyclic alkyl groups such as - (1-cycloheptylethyl) group, 1- (2-cycloheptylethyl) group and 2-norbornyl group.

Examples of the monomer for forming the repeating unit represented by the formula (2-1) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (Meth) acrylic acid ester, perfluoro n-propyl (meth) acrylate, perfluoro i-propyl (meth) acrylate, perfluoro n-butyl (Meth) acrylate ester, 1- (2,2,3,3-hexafluoropropyl) (meth) acrylate, perfluoro , 3,4,4,5,5-octafluoropentyl) (meth) acrylate, perfluorocyclohexylmethyl (meth) acrylate, 1- (2,2,3,3,3-pentafluoro Propyl) (meth) acrylic acid ester, 1- (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl ) (Meth) acrylic acid esters, 1- (5-trifluoro 3,3,4,4,5,6,6,6-octafluorohexyl) (meth) acrylate, and the like.

The content of the repeating unit (2-1) is preferably from 20 to 90 mol%, more preferably from 20 to 80 mol%, more preferably from 20 to 80 mol%, based on 100 mol% of the total repeating units of the (C) To 70 mol%. When the content is within the above range, there is an advantage that the balance between the water repellency in the formed photoresist film and the affinity to the developing solution is improved.

[1-3-2] Repeating unit represented by the formula (2-2):

Specific examples of the (g + 1) -linking group represented by R ⁶ in the general formula (2-2) include a (g + 1) -valent hydrocarbon group having 1 to 30 carbon atoms, a hydrocarbon group containing these hydrocarbon groups and an oxygen atom, a sulfur atom, , -CO-O- or -CO-NH-, and the like. When g is an integer of 1 to 3 and g is 2 or 3, the structures represented by the following formula (2-2a) in the formula (2-2) are mutually independent.

Of the (g + 1) -valent hydrocarbon groups having 1 to 30 carbon atoms, examples of R ^{6 in the} chain structure include methane, ethane, propane, butane, 2-methylpropane, pentane, 2-methylbutane, (G + 1) hydrogen atoms are removed from a chain hydrocarbon having 1 to 10 carbon atoms such as hexane, heptane, octane, nonane, decane, and the like.

Examples of R ^{6 in the} cyclic structure include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, A structure obtained by removing (g + 1) hydrogen atoms from alicyclic hydrocarbons having 4 to 20 carbon atoms such as tricyclo [3.3.1.1 ^3,7 ] decane; (G + 1) hydrogen atoms from aromatic hydrocarbons having 6 to 30 carbon atoms such as benzene, naphthalene and the like.

Regarding R ⁶ , examples of the combination structure of a hydrocarbon group and an oxygen atom, a sulfur atom, an imino group, a carbonyl group, -CO-O- or -CO-NH- include structures represented by the following formulas. In the following formulas, each R ²¹ independently represents a single bond, a divalent straight chain hydrocarbon group having 1 to 10 carbon atoms, a divalent cyclic hydrocarbon group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. g is an integer of 1 to 3;

Examples of the divalent straight chain hydrocarbon group having 1 to 10 carbon atoms represented by R ²¹ in the above formula include methane, ethane, propane, butane, 2-methylpropane, pentane, 2- methylbutane, , Heptane, octane, nonane, decane and the like. Examples of the divalent cyclic hydrocarbon group having 4 to 20 carbon atoms include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] Decane, tricyclo [3.3.1.1 ^3,7 ] decane, and the like. Examples of the divalent aromatic hydrocarbon group having 6 to 30 carbon atoms include groups derived from benzene, toluene, xylene, ethylbenzene, cumene, and the like. R ⁶¹ may have a substituent and examples of the substituent include a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2- methylpropyl group, Branched or cyclic alkyl group of 1 to 4 carbon atoms such as methyl, ethyl, n-propyl, and isopropyl.

The acid dissociable group represented by R ⁸ in the formula (2-2) may be the same as the acid dissociable group in the above-mentioned (A) polymer. Having such an acid dissociable group, the solubility of the (C) polymer present in the exposed portion can be improved. This is considered to be because acid generated in the exposure process in the resist pattern forming method described later and the acid dissociable group of the (C) polymer react to generate a polar group.

The alkali dissociable group represented by R ⁸ in the formula (2-2) is a group obtained by substituting a hydrogen atom in a polar functional group such as a hydroxyl group or a carboxyl group, and is a group dissociated in the presence of an alkali. Such an alkali dissociable group is not particularly limited as long as it exhibits the above properties, and examples thereof include groups represented by the following formula (2-2a1).

(In the formula (2-2a1), R ²² represents a hydrocarbon group of 1 to 10 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom)

As R ²² in the formula (2-2a1), a straight-chain or branched perfluoroalkyl group having 1 to 10 carbon atoms in which all the hydrogen atoms of the hydrocarbon group are substituted with a fluorine atom is preferable, and a trifluoromethyl group is more preferable.

Specific examples of the repeating unit (2-2) include a repeating unit represented by the following formula (7-1) and a repeating unit represented by the following formula (7-2).

(7-1) and (7-2), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ²⁴ represents a hydrogen atom, an acid dissociable group or an alkali dissociable group, -1), R ²³ represents a linking group of (g + 1), and in the formula (7-2), g is an integer of 1 to 3)

Examples of the compound for forming the repeating unit represented by the formula (7-1) and the repeating unit represented by the following formula (7-2) include specifically the compounds represented by the following formulas. In the formula, R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ²⁴ represents a hydrogen atom, an acid dissociable group or an alkali dissociable group.

For example, a compound wherein R ²⁴ in the above formula is an acid dissociable group or an alkaline dissociable group can be obtained from a compound wherein R ²⁴ is a hydrogen atom in the above formulas as a raw material. Specifically, the method for R ²⁴ is screen case of synthesizing the compound represented by Formula (2-2a1), R ²⁴ is a carboxylic acid by condensation of a fluoroalkyl ester is a hydrogen atom A compound in the presence of an acid in the above-mentioned general formula or , A method of condensation with a fluorocarboxylic acid halide in the presence of a base to effect esterification, and the like.

Examples of the fluorinated alkyl group having 1 to 10 carbon atoms represented by R ¹⁰ in the formula (2-2) include a linear or branched alkyl group having 1 to 6 carbon atoms substituted with at least one fluorine atom, at least one fluorine atom substituted with at least one fluorine atom A monovalent alicyclic hydrocarbon group having 4 to 10 carbon atoms or a group derived therefrom.

Specific examples of the structure represented by the following formula (2-2b) in the formula (2-2) include structures represented by the following formulas (8-1) to (8-5). Among them, a structure represented by the following formula (8-5) is preferable.

The content of the recurring unit (2-2) is preferably 80 mol% or less, more preferably 20 to 80 mol%, more preferably 30 to 70 mol%, based on 100 mol% of the total repeating units of the (C) Mol% is particularly preferable. When the content ratio is within the above range, there is an advantage that the difference between the advancing contact angle and the receding contact angle of the liquid for immersion lithography in the formed photoresist film can be reduced.

[1-3-3] Repeating unit represented by the formula (2-3):

The divalent linking group represented by R ⁷ in the formula (2-3) includes a divalent hydrocarbon group having 1 to 30 carbon atoms. Further, a combination structure of these hydrocarbon groups and a sulfur atom, imino group, carbonyl group, -CO-O- or -CO-NH- can be given.

Examples of the R ^{7 in the} chain structure include a hydrocarbon group having 1 to 20 carbon atoms such as methane, ethane, propane, butane, 2-methylpropane, pentane, 2-methylbutane, 2,2-dimethylpropane, hexane, heptane, And a divalent hydrocarbon group having a structure obtained by removing two hydrogen atoms from a chain hydrocarbon of 10 carbon atoms.

Examples of R ^{7 in the} cyclic structure include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, A divalent hydrocarbon group having a structure obtained by removing two hydrogen atoms from an alicyclic hydrocarbon having 4 to 20 carbon atoms such as tricyclo [3.3.1.1 ^3,7 ] decane; And divalent hydrocarbon groups having a structure obtained by removing two hydrogen atoms from aromatic hydrocarbons having 6 to 30 carbon atoms such as benzene and naphthalene.

Examples of the fluorinated alkyl group having 1 to 10 carbon atoms represented by R ¹⁰ in the formula (2-3) include a straight or branched alkyl group having 1 to 6 carbon atoms substituted with at least one fluorine atom, a carbon number substituted with at least one fluorine atom 4 to 10 monovalent alicyclic hydrocarbon groups or groups derived therefrom.

Specific examples of R ⁸ in the formula (2-3) include groups represented by the following formulas (2-3a1) to (2-3a3). Further, the formula (2-3a1), and (2-3a2) from, if R ²⁵ is represents a halogen atom, an alkyl group, an alkoxyl group, an acyl group or an acyloxy group having 1 to 10 carbon atoms, plurality of R ²⁵ are present, each R ²⁵ may be the same or different. m1 represents an integer of 0 to 5, and m2 represents an integer of 0 to 4; In the formula (2-3a3), R ²⁶ and R ²⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ²⁶ and R ²⁷ bond to each other to form an alicyclic structure having 4 to 20 carbon atoms .

Examples of the halogen atom represented by R ²⁵ in the formula (2-3a2) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Of these, a fluorine atom is preferable.

Specific examples of the alkyl group, alkoxy group, acyl group and acyloxy group having 1 to 10 carbon atoms represented by R ²⁵ in the formula (2-3a2) include a methyl group, a methoxy group and an acetyl group.

R &lt; ²⁶ &gt; in formula (2-3a3) Examples of the alkyl group having 1 to 10 carbon atoms represented by R &lt; ²⁷ &gt; include a methyl group, an ethyl group and an n-propyl group.

Examples of the alicyclic structure formed by combining R ²⁶ and R ²⁷ in the formula (2-3a3) together with the carbon atoms to which they are bonded include, for example, cyclopentyl, cyclopentylmethyl, 1- (1-cyclo (1-cyclohexylethyl) group, a 1- (2-cyclohexylethyl) group, a cyclohexyl group, a cyclohexylmethyl group, Cycloheptylmethyl group, 1- (1-cycloheptylethyl) group, 1- (2-cycloheptylethyl) group and 2-norbornyl group.

Specific examples of the group represented by the formula (2-3a3) include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, (3-methylbutyl) group, a neopentyl group, a 1-hexyl group, a 2-hexyl group, a 3-hexyl group , A 1- (2-methylpentyl) group, a 1- (3-methylpentyl) group, , 3- (2-methylpentyl) group and the like. Among them, a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group and a 2-butyl group are preferable.

Specific examples of the repeating unit (2-3) include those represented by the following formula (2-3-1).

(In the formula (2-3-1), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ⁷ represents a divalent linking group, and R ⁸ represents a hydrogen atom, an acid dissociable group or an alkali dissociable group )

Examples of the compound for forming the repeating unit represented by the formula (2-3-1) include compounds represented by the following formulas (2-3-1a) to (2-3-1d). In the formulas (2-3-1a) to (2-3-1d), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group. R ⁸ represents a hydrogen atom, an acid dissociable group or an alkali dissociable group.

The compound wherein R ⁸ in the formulas (2-3-1a) to (2-3-1d) is an acid dissociable group or an alkaline dissociable group can be prepared by, for example, reacting a compound or a derivative thereof in which R ⁸ is a hydrogen atom, . &Lt; / RTI &gt; For example, when R ⁸ is a group represented by the above formulas (2-3a1) to (2-3a3), these compounds can be obtained by reacting a compound represented by the formula (9-1) To (9-4). &Lt; / RTI &gt;

(9-1), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ⁷ represents a divalent linking group, each R ¹⁰ independently represents a hydrogen atom, a fluorine atom, With the proviso that not all of R ¹⁰ is a hydrogen atom, and R ²⁸ represents a hydroxyl group or a halogen atom)

(In the formula (9-2), R ²⁵ represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxyl group, an acyl group or an acyloxy group, and when a plurality of R ²⁵ is present, each R ²⁵ is the same or different , R ²⁹ represents a halogen atom, and m 1 represents an integer of 0 to 5)

(In the formula (9-3), R ²⁵ represents a halogen atom, an alkyl group, an alkoxyl group, an acyl group or an acyloxy group having 1 to 10 carbon atoms, and when a plurality of R ²⁵ is present, each R ²⁵ is the same or different R &lt; ³⁰ &gt; represents a halogen atom, and m2 represents an integer of 0 to 4)

(In the formula (9-4), R ²⁶ and R ²⁷ each independently represent an alkyl group having 1 to 10 carbon atoms)

The halogen atom represented by R ²⁹ in the formula (9-2) is preferably a chlorine atom.

The halogen atom represented by R ³⁰ in the formula (9-3) is preferably a boron atom.

Examples of the alkyl group having 1 to 10 carbon atoms represented by R ²⁶ or R ²⁷ in the formula (9-4) include a methyl group, an ethyl group and an n-propyl group.

When R ⁸ in the formula (2-3) is a group represented by the above formulas (2-3a1) to (2-3a3), the compound having such a group is, for example, a compound represented by the following formula (10-1) With a compound represented by the following formula (10-2).

In (formula (10-1), R ⁷ represents a divalent connecting group, R ⁸ has the formula (2-3a1) to (represents a group represented by the 2-3a3), R ¹⁰ is a hydrogen atom, a fluorine atom, each independently , Or a fluorinated alkyl group having from 1 to 10 carbon atoms, with the proviso that not all R ¹⁰ are hydrogen atoms)

(In the formula (10-2), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ⁴⁷ represents a hydroxyl group or a halogen atom)

The content of the repeating unit (2-3) is preferably 50 mol% or less, more preferably 5 to 30 mol%, more preferably 5 to 20 mol%, based on 100 mol% of the total repeating units of the polymer (C) Mol% is particularly preferable. When the content is within the above range, there is an advantage that the balance between the water repellency in the formed photoresist film and the affinity to the developing solution is improved.

The polymer (C) preferably has at least one repeating unit selected from the group consisting of the repeating unit (2-1), the repeating unit (2-2) and the repeating unit (2-3) as described above (2-1) to (2-3), or two or more repeating units may be used, and it is preferable to have two or more repeating units (2-2) and repeating units (2-3).

If the (C) polymer has an alkali dissociable group in at least one of the repeating unit (2-2) and the repeating unit (2-3), the affinity of the (C) polymer with the developing solution can be improved. This is presumably because (C) the polymer reacts with the developer in the developing step of the resist pattern forming method to be described later, and a polar group is generated. When R ⁸ in the formulas (2-2) and (2-3) is a hydrogen atom, the repeating units (2-2) and (2-3) have a hydroxyl group or a carboxyl group which is a polar group. When the polymer (C) contains such a repeating unit, the affinity of the polymer (C) to the developing solution can be improved in the developing step of the resist pattern forming method described later.

[1-3-4] Repeating unit (i):

(C) the polymer is a repeating unit containing at least one group selected from the group consisting of a group represented by the following formula (2-4) and a group represented by the following formula (2-5) (provided that the repeating unit represented by the above formula (2-3) (Hereinafter sometimes referred to as &quot; repeating unit (i) &quot;). By further having such a repeating unit (i), the solubility of the formed photoresist film in a developing solution is improved.

(In the formula (2-4), R ¹¹ represents a hydrocarbon group having 1 to 10 carbon atoms substituted with a fluorine atom)

The hydrocarbon group having 1 to 10 carbon atoms substituted with a fluorine atom represented by R ¹¹ in the formula (2-4) is not particularly limited as long as one or two or more hydrogen atoms in the hydrocarbon group having 1 to 10 carbon atoms are substituted with a fluorine atom. A trifluoromethyl group and the like are preferable.

The main chain skeleton of the repeating unit (i) is not particularly limited, but methacrylic acid ester, acrylic acid ester,? -Trifluoroacrylic acid ester, and the like are preferable.

Examples of the repeating unit (i) include a repeating unit derived from a compound represented by the following formula (11-1) and a repeating unit derived from a compound represented by the following formula (11-2).

(11-1) and (11-2), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ³² represents a single bond or a divalent linear, branched or cyclic alkyl group having 1 to 20 carbon atoms (11-1), R ³¹ represents a hydrocarbon group of 1 to 10 carbon atoms substituted with a fluorine atom, and t represents 0 or 1)

As the bivalent straight, branched or cyclic, saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms and represented by R ³² in the formulas (11-1) and (11-2), the divalent group represented by R ²⁰ in the formula The same as the organic group can be exemplified. The hydrocarbon group having 1 to 10 carbon atoms substituted with a fluorine atom represented by R ³¹ in the formula (11-1) is not particularly limited as long as one or two or more hydrogen atoms in the hydrocarbon group having 1 to 10 carbon atoms are substituted with a fluorine atom , For example, a trifluoromethyl group and the like are preferable.

The repeating units (i) may be used singly or in combination of two or more.

The content of the repeating unit (i) is preferably 50 mol% or less, more preferably 5 to 30 mol%, and more preferably 5 to 20 mol%, based on 100 mol% of the total repeating units of the (C) Is particularly preferable. When the content is within the above range, there is an advantage that the balance between the water repellency in the formed photoresist film and the affinity to the developing solution is improved.

[1-3-5] Other repeating units (b):

The polymer (C) may contain, in addition to the repeating units (2-1) to (2-3) and the repeating units (i), other repeating units (b).

Examples of the other repeating units (b) include the repeating units represented by the above formulas (2-1) to (2-5).

Among the repeating units represented by the formula (2-1), the repeating units represented by the following formula (12) are preferable. By including the repeating unit represented by the following formula (12), it is possible to reduce the difference between the advancing contact angle and the receding contact angle of the photoresist film, thereby improving the scanning speed upon immersion exposure.

(Wherein R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ³³ represents a straight or branched alkyl group having 1 to 4 carbon atoms, and k represents an integer of 1 to 4)

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ³³ in the formula (12) include a methyl group, an ethyl group, a n-propyl group, an i-propyl group, -Methylpropyl group, t-butyl group and the like.

The polymer (C) contains a fluorine atom, and even when the polymer (A) contains a fluorine atom, the content of the fluorine atom is larger than that of the polymer (A). The fluorine atom content is usually 5% by mass or more, preferably 5% by mass to 50% by mass, and more preferably 5% by mass to 40% by mass, based on 100% by mass of the total amount of the (C) When the content of fluorine atoms in the polymer (C) is within the above range, the water repellency of the photoresist film to be formed can be increased, and a photoresist film having good water repellency can be formed without forming a liquid immersion upper layer film during liquid immersion exposure . When the content is smaller than that of the polymer (A), the degree of oil repellency between the polymer (A) and the polymer (C) may be reversed. When the degree of oil repellency is reversed, The effect of the present invention can not be obtained because the polymer is unevenly distributed on the surface layer of the photoresist film.

The content of the (C) polymer is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, particularly preferably 1 to 5 parts by mass, relative to 100 parts by mass of the (A) When the content is in the above-mentioned range, (C) the polymer is localized on the surface layer of the photoresist film, so that there is an effect that good water repellency is obtained.

The weight average molecular weight (Mw) of the polymer (C) in terms of polystyrene as determined by gel permeation chromatography (GPC) is preferably 1,000 to 50,000, more preferably 1,000 to 40,000, and particularly preferably 1,000 to 30,000 . If the Mw is less than 1,000, a photoresist film having a sufficient retreating contact angle can not be obtained, and there is a fear that defects resulting from using liquid for immersion lithography may occur. On the other hand, if it is more than 50,000, development of the photoresist film may be deteriorated. The ratio (Mw / Mn) of the Mw of the polymer (C) to the number average molecular weight (Mn) in terms of polystyrene determined by the GPC method is preferably 1 to 5, and more preferably 1 to 4.

In addition, the polymer (C) is preferable as the content of impurities such as halogen and metal is small, like the polymer (A). When the content of such impurities is small, the sensitivity, resolution, process stability, pattern shape and the like of the photoresist film can be further improved.

The polymer (C) can be obtained by, for example, using a monomer (polymerizable unsaturated monomer) for forming each of the repeating units described above by a radical polymerization initiator such as hydroperoxides, dialkyl peroxides, diacyl peroxides, And, if necessary, in the presence of a chain transfer agent in an appropriate solvent.

The solvent used in the polymerization may be the same as the solvent used in the polymerization of the (A) polymer. The reaction temperature in the polymerization is usually 40 to 150 占 폚, preferably 50 to 120 占 폚. The reaction time is usually 1 to 48 hours, preferably 1 to 24 hours.

[1-4] Other ingredients:

The radiation sensitive resin composition of the present invention may further contain other components in addition to the (A) polymer, (B) the radiation-sensitive acid generator and (C) the polymer. Examples of other components include acid diffusion control agents, solvents, lactone compounds, and other additives (for example, alicyclic additives, surfactants, sensitizers, halation inhibitors, adhesion aids, storage stabilizers, .

[1-4-1] Acid diffusion control agent:

Examples of the acid diffusion control agent include compounds represented by the following general formula (13) (hereinafter sometimes referred to as "nitrogen-containing compounds (I)"), compounds having two nitrogen atoms in the same molecule Compound (II) "), a compound having three or more nitrogen atoms (hereinafter sometimes referred to as" nitrogen-containing compound (III) "), an amide group-containing compound, a urea compound, And heterocyclic compounds. When such an acid diffusion control agent is further included, the pattern shape and dimensional fidelity can be improved.

(Wherein R ³⁴ to R ³⁶ independently represent a hydrogen atom, a linear, branched or cyclic alkyl group which may be substituted, an aryl group, an aralkyl group, or an acid dissociable group)

Examples of the acid dissociable group in the compound represented by the formula (13) include a group represented by the formula (13-1).

(In the formula (13-1), R ³⁷ to R ³⁹ independently represent a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a group derived therefrom Or R ³⁸ and R ³⁹ are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a group derived therefrom together with the carbon atoms to which they are bonded and R ³⁷ represents a straight chain Or a branched alkyl group, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a group derived therefrom)

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ³⁷ to R ³⁹ in the formula (13-1) include methyl, ethyl, n-propyl, i-propyl, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ³⁷ to R ³⁹ in the formula (13-1) include norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane , Groups containing an alicyclic ring derived from cycloalkanes such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and the like.

As the bivalent alicyclic hydrocarbon group having 4 to 20 carbon atoms and the group derived therefrom, R ³⁸ and R ³⁹ in the formula (13-1) are bonded to each other to form a bivalent The alicyclic hydrocarbon group may be substituted with an alicyclic hydrocarbon group having 1 to 4 carbon atoms such as a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2- And groups substituted by one or more of linear, branched or cyclic alkyl groups.

Specific examples of the nitrogen-containing compound (I) having no acid dissociable group include trialkyl amines such as tri-n-hexylamine, tri-n-heptylamine and tri-n-octylamine.

Specific examples of the nitrogen-containing compound (I) having an acid dissociable group include Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonyl- ', N' '- dicyclohexylamine, and the like.

Specific examples of the nitrogen-containing compound (II) include N, N, N ', N'-tetrakis (2-hydroxypropyl) ethylenediamine.

Specific examples of the nitrogen-containing compound (III) include a polymer of polyethyleneimine, polyallylamine, dimethylaminoethylacrylamide, and the like.

Examples of the nitrogen-containing heterocyclic compound include 2-phenylbenzimidazole and N-t-butoxycarbonyl-2-phenylbenzimidazole.

As the acid diffusion control agent, a compound represented by the following formula (14) may also be used.

Wherein X ⁺ is a cation represented by the following formula (14-1) or (14-2), Z ^- is OH ^- , and R ⁴¹ -COO ^- in the formula (14-3) anion, formula (14-4) R ⁴⁰ -SO ₃ ^- anion, or the general formula (14-5) R ⁴⁰ -N represented by ^- being the anion represented by -SO ₂ -R ^41, only the general formula (14 3) to (14-5), R ⁴⁰ is an alkyl group, an alicyclic hydrocarbon group or an aryl group which may be substituted, and R ⁴¹ is a fluorinated alkyl group, an alicyclic fluorinated hydrocarbon group or a fluorinated aryl group which may be substituted,

In the formula (14-1), R ⁴² to R ⁴⁴ independently represent a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom, and R ⁴⁵ and R ⁴⁶ in the formula (14-2) An alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom.

The compound represented by the above formula (14) is used as an acid diffusion control agent (hereinafter also referred to as &quot; photodegradable acid diffusion control agent &quot;) which is decomposed by exposure and loses acid diffusion controllability. By containing the compound represented by the general formula (14), the acid is diffused in the exposed portion and the acid diffusion is controlled in the unexposed portion, so that the contrast between the exposed portion and the unexposed portion is excellent It is effective to improve the LWR, MEEF (Mask Error Enhancement Factor) of the radiation sensitive resin composition of the present invention (amplification factor of the deviation of the line width due to the mask width deviation).

X ^& lt ^{; +} &gt; in the general formula (14) is a cation represented by the general formula (14-1) or (14-2) as described above. In the formula (14-1), R ⁴² to R ⁴⁴ independently represent a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom, and among them, the solubility of the compound represented by the formula (14) It is preferably a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. In the formula (14-2), R ⁴⁵ and R ⁴⁶ independently represent a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group or a halogen atom, and among these, a hydrogen atom, an alkyl group and a halogen atom are preferable.

Z ^- in the general formula (14) is OH ^- , an anion represented by the formula (14-3) R ⁴⁰ -COO ^- , an anion represented by the formula (14-4) R ⁴⁰ -SO ₃ ^{- 40} -N ^- is an anion represented by -SO ₂ -R ⁴¹ (however, in the above formula (14-3) to (14-5), R ⁴⁰ is optionally substituted alkyl group, an alicyclic hydrocarbon group or an aryl group , R ⁴¹ is a fluorinated alkyl group which may be substituted, an alicyclic fluorinated hydrocarbon group or a fluorinated aryl group).

Among these acid diffusion control agents, a nitrogen-containing compound (I), a nitrogen-containing compound (II), a nitrogen-containing heterocyclic compound, and a photodegradable acid diffusion control agent are preferable. The acid diffusion controlling agents may be used alone or in combination of two or more.

The content of the acid diffusion control agent is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the (A) polymer. When the content of the acid diffusion control agent is more than 10 parts by mass, the sensitivity of the formed photoresist film may be significantly reduced.

[1-4-2] Solvent:

Examples of the solvent include linear or branched ketones; Cyclic ketones; Propylene glycol monoalkyl ether acetates; Alkyl 2-hydroxypropionate; And 3-alkoxypropionic acid alkyls.

These solvents may be used singly or in combination of two or more. Of these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, 2-hydroxypropionic acid alkyls, 3- Alkoxypropionic acid alkyls are preferred.

[1-4-3] Lactone compound:

The lactone compound (C) effectively localizes the polymer on the surface layer of the photoresist film. That is, by including such a lactone compound, even if the amount of the polymer (C) that exhibits water repellency on the surface layer of the photoresist film in liquid immersion exposure is lower than the conventional amount, the water repellency of the surface layer of the photoresist film can be maintained. In addition to not impairing the basic properties such as LWR, development defects and pattern decay resistance, it is also possible to suppress the elution of components in the photoresist film (such as acid generator (B)) into liquid for immersion lithography, A droplet is hardly left on the photoresist film. Therefore, a photoresist film capable of suppressing defects derived from a liquid for immersion lithography such as a watermark defect can be formed.

Examples of the lactone compound include? -Butyrolactone, valerolactone, mevalonic lactone and norbornane lactone. The lactone compounds may be used alone or in combination of two or more.

The amount of the lactone compound to be used is preferably 30 to 200 parts by mass, more preferably 50 to 150 parts by mass based on 100 parts by mass of the (A) polymer. When the amount is used within the above range, the polymer (C) can be distributed on the surface layer of the photoresist film even when the amount of the polymer (C) to be used is small. If the amount is less than 30 parts by mass, the water repellency of the surface layer of the photoresist film may not be sufficiently obtained when the amount of the polymer (C) used is small. On the other hand, if it exceeds 200 parts by mass, the basic performance and shape of the formed photoresist film may be remarkably deteriorated.

The radiation sensitive resin composition of the present invention can be obtained, for example, by mixing (A) a polymer, (B) a radiation-sensitive acid generator, (C) a polymer and other components (excluding a solvent) Is dissolved in a solvent such that the amount of the solution is 1 to 50% by mass (preferably 1 to 25% by mass), and then filtered with a filter having a pore size of about 0.2 m, for example.

[2] Method of forming resist pattern:

The method for forming a resist pattern of the present invention comprises the steps of: forming a photoresist film by coating a radiation sensitive resin composition of the present invention on a substrate; disposing a liquid for immersion lithography on the formed photoresist film; An exposure step of irradiating the photoresist film with radiation through a liquid for immersion lithography, and a developing step of developing the photoresist film irradiated with the radiation with a developing solution to form a resist pattern. According to this method, it is possible to form a resist pattern having a good LWR and a reduced film loss.

[2-1] Photoresist film forming step:

The photoresist film forming process is a process for forming a photoresist film by coating the radiation sensitive resin composition of the present invention on a substrate.

Examples of the substrate include a silicon wafer, a wafer coated with aluminum, and the like.

As a method of forming a photoresist film on a substrate, there can be mentioned, for example, a method in which a composition solution obtained by dissolving the radiation sensitive resin composition of the present invention in a solvent is applied on a substrate by a conventionally known method such as spin coating, And the like.

The thickness of the photoresist film is not particularly limited, and may be the same as that of a conventionally known photoresist film.

After forming the photoresist film, the photoresist film may be subjected to a heat treatment (hereinafter sometimes referred to as &quot; PB &quot;).

[2-2] Exposure step:

The exposure step is a step of disposing a liquid for immersion exposure on the formed photoresist film and irradiating the photoresist film with radiation through the immersion exposure liquid.

Examples of liquids for immersion exposure include pure water and fluorine-based inert liquids.

Examples of light such as radiation used for exposure include visible light, ultraviolet light, far ultraviolet light, X-ray, and charged particle light, and the like. Among them, ultraviolet light represented by ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) is preferable, and ArF excimer laser (wavelength 193 nm) is particularly preferable.

The exposure conditions such as the exposure amount can be appropriately selected in accordance with the composition of the photoresist composition and the kind of the additive. After the exposure, it is preferable to carry out the heat treatment (the heat treatment after exposure is hereinafter sometimes referred to as &quot; PEB &quot;). This is because the dissociation reaction of the acid dissociable group in the polymer (A) proceeds smoothly by PEB. The heating conditions of PEB vary depending on the composition of the photoresist composition, but are usually 30 to 200 캜, preferably 50 to 170 캜.

In order to maximize the potential of the radiation sensitive resin composition, an organic or inorganic antireflection film may be formed on the substrate before forming the photoresist film (see, for example, Japanese Patent Publication No. 6 -12452 (Japanese Patent Laid-Open Publication No. 59-93448). A protective film (see, for example, Japanese Patent Application Laid-Open (kokai) No. 5-188598 and the like) may be formed on the photoresist film in order to prevent the influence of basic impurities contained in the environmental atmosphere. In addition, the radiation sensitive resin composition of the present invention can form a photoresist film which does not form a liquid immersion layer film, that is, a LWR after development and a film hardly decreases, An immersion upper layer film as disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-352384 may be formed. These techniques can also be used in combination.

[2-3] Development process:

The developing process is a process for forming a resist pattern by developing a photoresist film irradiated with radiation with a developing solution.

Examples of the developing solution used in the development include aqueous solutions such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di- , Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7- undecene, 1,5-diazabicyclo- [4.3.0] -5-nonene, and the like are preferably dissolved in an alkaline aqueous solution obtained by dissolving at least one kind of alkaline compound. The concentration of the alkaline aqueous solution is usually 10 mass% or less. If the concentration of the alkaline aqueous solution exceeds 10% by mass, the unexposed portion may also be dissolved in the developer.

An organic solvent may further be added to the developer containing the alkaline aqueous solution. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, and 2,6-dimethylcyclohexanone; There may be mentioned alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, Alcohols; Ethers such as tetrahydrofuran and dioxane; Esters such as ethyl acetate, n-butyl acetate and i-amyl acetate; Aromatic hydrocarbons such as toluene and xylene, phenol, acetonyl acetone, and dimethylformamide. These organic solvents may be used alone or in combination of two or more. The amount of the organic solvent to be added is preferably 100% by volume or less based on the alkaline aqueous solution. When the addition amount of the organic solvent exceeds 100% by volume, the developability is lowered, and there is a possibility that the developing residue of the exposed portion increases. A surfactant or the like may be added in an appropriate amount to a developer containing an alkaline aqueous solution. Further, after development with a developer containing an alkaline aqueous solution, it is usually washed with water and dried.

Example

Hereinafter, the present invention will be described concretely on the basis of Examples and Comparative Examples, but the present invention is not limited to these Examples and Comparative Examples. In the case where "part" and "%" are simply referred to, they are on a mass basis unless otherwise specified. Methods for measuring various physical properties and evaluation methods for various properties are shown below.

[Elution amount]:

A silicone-based resin film was formed by spin coating a radiation-sensitive resin composition (composition solution) on a silicon wafer with CLEAN TRACK ACT 8 (manufactured by Tokyo Electron Co., Ltd.) and baking at 100 캜 for 60 seconds to form a resist film having a film thickness of 150 nm . A Teflon ring having a diameter of 1 cm and a thickness of 1 mm was placed on the silicon wafer, and 1 mL of ultrapure water was filled thereon so that the ultrapure water and the resist film were in contact with each other. The ultrapure water and the resist film were contacted for 3 seconds, 5 seconds, 10 seconds, 30 seconds, 60 seconds, 120 seconds, and 300 seconds, respectively, and then the filled ultrapure water was collected by a glass syringe and used as an analysis sample. The recovery rate of the ultrapure water after the completion of the experiment was 95% or more.

Subsequently, the peak intensity of the anion portion of the photoacid generator in the obtained ultrapure water was measured using a single "CAPCELL PAK MG" manufactured by Shiseido Co., Ltd. as a use column at a flow rate of 0.2 ml / min and a measurement temperature of 35 ° C in water / methanol (Liquid chromatography mass spectrometer, LC part: SERIES 1100, manufactured by AGILENT, MS part: Mariner (manufactured by Perseptive Biosystems, Inc.)) under the measurement conditions using 0.1 mass% ). &Lt; / RTI &gt;

At this time, each peak intensity of 1 ppb, 10 ppb, and 100 ppb aqueous solutions of the photoacid generator was measured under the above measurement conditions to prepare a calibration curve, and the amount of elution was calculated from the peak intensity using the calibration curve. The evaluation criteria were "poor" when the elution amount was 2.0 × 10 ^-12 mol / cm ² / sec or more, and "good" when the elution amount was less than 2.0 × 10 ^-12 mol / cm ² / sec.

[Sensitivity]:

A 12-inch silicon wafer on which a lower antireflection film (&quot; ARC66 &quot;, manufactured by Nissan Chemical Industries, Ltd.) having a thickness of 105 nm was formed was coated on the surface of this silicon wafer by spin coating on the thin film of the substrate, Soft baking (SB) (indicated by &quot; SB &quot; in Table 5) for 60 seconds at the temperature (100 DEG C) shown in Table 5 was performed to form a resist film having a film thickness of 90 nm. The formed resist film having a film thickness of 90 nm was exposed through a mask pattern using a full-field reduction projection liquid immersion exposure apparatus "S610C" (numerical aperture of 1.30) manufactured by Nikon Corporation. Thereafter, the resultant was subjected to PEB at a temperature shown in Table 5 for 60 seconds, developed with a 2.38% by mass aqueous solution of TMAH at 25 DEG C for 30 seconds, washed with water and dried to form a positive resist pattern. At this time, the exposure amount (mJ / cm ² ) in which the line width formed through the 1-to-1 line-and-space mask having the dimension of 45 nm is formed in the 1-line and 1-line space with the line width of 45 nm is set as the optimum exposure amount, mJ / cm ² ) was defined as &quot; sensitivity &quot;.

[Line Width Roughness (LWR)]:

A 45 nm (1L / 1S) pattern was formed on the resist film at the optimum exposure amount for evaluation of the above [sensitivity], and a 45 nm (1L / 1S) pattern was formed on the resist film by a length measuring SEM (model number CG4000, manufactured by Hitachi High- Quot;) was observed from above the pattern, and the line width was measured at an arbitrary point. The measurement fluctuation with respect to the line width was expressed by 3 sigma, and the LWR was evaluated by this value.

[Top Loss]:

The pattern section was observed with a scanning electron microscope (SEM) "S-4800" manufactured by Hitachi High-Technologies Corporation, and the height (pattern height) thereof was measured by observing the 45 nm1L / 1S pattern resolved at the optimum exposure amount. Then, the value of the pattern height was subtracted from the initial film thickness (90 nm), and the upper loss amount was calculated. The upper loss was evaluated by this upper loss amount.

Further, the respective polymers (A-1) to (A-8) ((A) polymers) were synthesized by using the compounds represented by the following formulas (M-1) to .

(Synthesis Example 1)

(Preparation of polymer (A-1)

, 54.19 g (50 mol%) of the compound (M-8) represented by the formula (M-1), 24.61 g (30 mol%) of the compound (M- 9.08 g (10 mol%) of the compound (M-9) represented by the formula (M-9) was dissolved in 200 g of 2-butanone, and further 4.00 g of dimethyl 2,2'-azobisisobutyronitrile was added thereto, A monomer solution was prepared.

On the other hand, a 1000 mL three-necked flask charged with 12.11 g of the compound (M-5) represented by the formula (M-5) and 100 g of 2-butanone was purged with nitrogen for 30 minutes, Deg.] C, and the previously prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The initiation of dropwise addition was regarded as the polymerization initiation time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization, the polymerization solution was cooled to 30 캜 or lower by water-cooling. Thereafter, the solution was poured into 2000 g of methanol to precipitate a white powder, and the precipitated white powder was filtered off. The white powder obtained by filtration was washed twice with 400 g of methanol as a slurry. Thereafter, the mixture was separated by filtration and dried at 50 DEG C for 17 hours to obtain a white powder copolymer (yield: 79 g, yield: 79%).

The copolymer had a Mw of 5500 and a Mw / Mn ratio of 1.41. As a result of ¹³ C-NMR analysis, the compound (M-1), the compound represented by the formula (M- 9) represented by the formula (M-5), the compound represented by the formula (M-8) and the compound represented by the formula (M-9) (Mol%) were 30.2: 9.9: 10.2: 49.7, respectively. This copolymer was referred to as Polymer (A-1). The physical properties of the polymer (A-1) are shown in Table 3.

(Synthesis Examples 2 to 8)

(Preparation of polymers (A-2) to (A-8)

Polymers (A-2) to (A-8) were prepared in the same manner as in Synthesis Example 1 except that the compound (monomer type) shown in Table 1 and the blend ratio were used. The physical properties of the polymers (A-2) to (A-8) are shown in Table 3.

(Synthesis Example 9)

(Preparation of polymer (C-1)) [

30.06 g (15 mol%) of the compound (M-13) represented by the formula (M-3) and 50.88 g (60 mol%) of the compound (M- 19.06 g (25 mol%) of the compound (M-14) represented by the formula (14) shown below was dissolved in 100 g of 2-butanone and 3.55 g of dimethyl 2,2'-azobisisobutyronitrile was added thereto to obtain a monomer solution . On the other hand, 100 g of 2-butanone was introduced into a 1000 mL three-necked flask, purged with nitrogen for 30 minutes, and then heated to 80 DEG C while stirring the reaction kettle.

Subsequently, the previously prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The initiation of dropwise addition was regarded as the polymerization initiation time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization, the polymerization solution was cooled to 30 캜 or lower by water cooling, and the polymerization solution was transferred to a 2 L separating funnel. Thereafter, the polymerization solution was diluted with 300 g of n-hexane, 1200 g of methanol was added and mixed, and the mixture was allowed to stand for 30 minutes. The lower layer was recovered to prepare a propylene glycol monomethyl ether acetate solution.

The yield of the solid (polymer) of the propylene glycol monomethyl ether acetate solution was 65%, Mw was 6400, and Mw / Mn was 1.41. As a result of ¹³ C-NMR analysis, the fluorine content was 9.14% Derived from a compound represented by the formula (M-14), a compound represented by the formula (M-13) and a compound represented by the formula (M-14) (Mol%) were 60.3: 24.9: 14.8, respectively. This copolymer was referred to as polymer (C-1).

(Synthesis Examples 10 to 12)

Polymers (C-2) to (C-4) were prepared in the same manner as in Synthesis Example 9 except that the compound (monomer type) and the blending ratio shown in Table 2 were used. The physical properties of the polymers (C-2) to (C-4) are shown in Table 3.

Next, &quot; acid generator &quot; and &quot; acid diffusion control agent &quot; used in Examples and Comparative Examples are shown below.

The &quot; solvent &quot; and &quot; additive &quot; used in Examples and Comparative Examples are shown below.

Solvent (E-1): Propylene glycol monomethyl ether acetate,

Solvent (E-2): Cyclohexanone,

Additive (F-1):? -Butyrolactone.

(Example 1)

, 10 parts of a compound (B-1) represented by the above formula (B-1) as an acid generator (B), 100 parts of a polymer (A- , 2 parts of the polymer (C-1) prepared in Synthesis Example 9, 1.2 parts of the compound (D-1) represented by the formula (D-1) as an acid diffusion control agent, 1800 parts of the solvent (E-1) , 750 parts of the solvent (E-2) and 30 parts of the additive (F-1) as an additive were mixed to prepare a composition solution comprising the radiation-sensitive resin composition. The above-mentioned various evaluations were carried out using the prepared composition solution.

The radiation-sensitive resin composition of this example had a good evaluation of the amount of elution, a value at the evaluation of sensitivity of 20.0 mJ / cm ² , a value at the evaluation of LWR of 3.5 nm and a value at the evaluation of the upper loss Was 15 nm.

(Examples 2 to 18 and Comparative Examples 1 to 4)

A composition solution containing each radiation-sensitive resin composition was prepared in the same manner as in Example 1, except that the compound and the compounding amount shown in Table 4 were used. Each of the prepared composition solutions was subjected to the various evaluations described above. The evaluation results are shown in Table 5.

As is evident from Table 5, it was confirmed that the radiation-sensitive resin compositions of Examples 1 to 18 had better LWR after development than the radiation-sensitive resin compositions of Comparative Examples 1 to 4, and that film reduction was less likely to occur .

The radiation sensitive resin composition of the present invention is suitable as a resist used in a lithography technique in the field of semiconductor production. The resist pattern forming method of the present invention is suitable as a method of forming a fine pattern in a lithography technique in the field of semiconductor manufacturing.

Claims (7)

(A) a polymer having a repeating unit represented by the following formula (1) and an acid dissociable group,
(B) a radiation-sensitive acid generator,
(C) a polymer containing a fluorine atom and having no crosslinking group
/ RTI &gt;
The acid dissociable group of the polymer (A) is a group represented by the formula: -C (R) ₃ ,
A group represented by the above-mentioned chemical formula &quot; -C (R) ₃ &quot; is a group in which two Rs are bonded to each other to form a bivalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a group derived therefrom And the remaining one R is a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a group derived therefrom,
Wherein the two Rs are bonded to each other so that the bivalent alicyclic hydrocarbon group having 4 to 20 carbon atoms is an adamantylene group together with the carbon atoms bonded to each other.
&Lt; Formula 1 &gt;

(Wherein R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² represents a single bond, a divalent hydrocarbon group having 1 to 5 carbon atoms, an alkanediyloxy group or an alkanediylcarbonyloxy group, R ³ represents a trivalent organic group) The radiation-sensitive resin composition according to claim 1, wherein the repeating unit represented by the formula (1) is a repeating unit represented by the following formula (1-1).

Wherein R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² represents a single bond, a divalent hydrocarbon group having 1 to 5 carbon atoms, an alkanediyloxy group or an alkanediylcarbonyl Oxy group, and R ⁵⁰ represents a group represented by the following formula (a) or a group represented by the following formula (b)
<Formula a>

<Formula b>

(Wherein, in the formula (a), n1 represents an integer of 0 to 2, and in the formula (b), n2 to n5 each independently represent an integer of 0 to 2, are shown the coupling hand bonded to the R ^2, only there are one or more of the carbon atoms constituting a group these groups represented by the group) and (b represented by the formula (a) may be substituted with an oxygen atom, a nitrogen atom or a carbonyl group, and The group represented by the formula (a) and the group represented by the formula (b) may have a substituent) The radiation-sensitive resin composition according to claim 2, wherein the repeating unit represented by the formula (1) is a repeating unit represented by the following formula (1-1a).

Wherein R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² represents a single bond, a divalent hydrocarbon group having 1 to 5 carbon atoms, an alkanediyloxy group or an alkanediylcarbonyl And R ⁵¹ represents a group represented by the following formula (a1) or a group represented by the following formula (b1)
<Formula a1>

<Formula b1>

(In the formulas (a1) and (b1), * represents a bonding bond binding to R ² in the formula (1-1a)). The radiation sensitive resin composition according to claim 1, wherein the (C) polymer has at least one repeating unit selected from the group consisting of repeating units represented by the following formulas (2-1) to (2-3) Composition.

(2-1) to (2-3), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and in the formula (2-1), R ⁹ represents a fluorinated alkyl group having 1 to 30 carbon atoms , of the general formula (2-2), R ⁶ represents a single bond or a (g + 1) represents a divalent connecting group, g is an integer from 1 to 3, the formula (2-3) in a, R ⁷ represents a divalent linking group (2-2) and (2-3), R ⁸ represents a hydrogen atom, an acid dissociable group or an alkali dissociable group, each of R ¹⁰ independently represents a hydrogen atom, a fluorine atom, Fluorinated alkyl group, provided that when all of R &lt; ¹⁰ &gt; is a hydrogen atom, it is not) The positive resist composition according to claim 4, wherein the polymer (C) is a repeating unit containing at least one group selected from the group consisting of a group represented by the following formula (2-4) and a group represented by the following formula (2-5) -3)) is further contained in the radiation-sensitive resin composition.

(In the formula (2-4), R ¹¹ represents a hydrocarbon group having 1 to 10 carbon atoms substituted with a fluorine atom) The radiation sensitive resin composition according to claim 5, wherein the content of the (C) polymer is 0.1 to 40 parts by mass relative to 100 parts by mass of the (A) polymer. A photoresist film forming process for forming a photoresist film by coating the substrate with the radiation sensitive resin composition according to any one of claims 1 to 6,
An exposure step of disposing a liquid for immersion exposure on the formed photoresist film and irradiating the photoresist film with radiation through the immersion exposure liquid;
A developing step of developing the photoresist film irradiated with the radiation with a developer to form a resist pattern
To form a resist pattern.