JP5581726B2 - Radiation-sensitive resin composition and resist pattern forming method - Google Patents

Description

  The present invention relates to a radiation-sensitive resin composition and a resist pattern forming method. More specifically, the present invention relates to a radiation-sensitive resin composition and a resist pattern forming method capable of forming a photoresist film that has good line width roughness (LWR) after development and is less likely to cause film reduction.

  In the field of microfabrication for manufacturing integrated circuit elements, in order to obtain a higher degree of integration, a lithography technique capable of microfabrication at a level of 0.10 μm or less (that is, a sub-quarter micron level) is eagerly desired. However, in the conventional lithography technique, near ultraviolet rays such as i-line are used as radiation, and fine processing at a level of 0.10 μm or less is extremely difficult with this near ultraviolet rays. Therefore, in order to enable microfabrication at a level of 0.10 μm or less, development of a lithography technique using radiation having a shorter wavelength is being performed. Examples of radiation having a shorter wavelength include an emission line spectrum of a mercury lamp, far ultraviolet rays such as an excimer laser, an X-ray, and an electron beam. Among these, KrF excimer laser (wavelength 248 nm) and ArF excimer laser (wavelength 193 nm) are attracting attention.

  With the excimer laser's attention, a lot of materials for excimer laser photoresist films (compositions for excimer lasers) have been proposed. A composition containing a group-containing component and a component (hereinafter referred to as “acid generator”) that generates an acid upon irradiation with radiation (hereinafter referred to as “exposure”), and using these chemical amplification effects ( (Hereinafter referred to as “chemically amplified resist”). Specifically, as the chemically amplified resist, a composition containing a resin having a t-butyl ester group of carboxylic acid or a t-butyl carbonate group of phenol and an acid generator has been reported. This composition has an acidic property consisting of a carboxyl group or a phenolic hydroxyl group in the resin by dissociation of a t-butyl ester group or t-butyl carbonate group present in the resin by the action of an acid generated by exposure. The group is exposed. As a result, the exposed region becomes readily soluble in an alkali developer, and a desired resist pattern can be formed by developing with an alkali developer.

  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). In order to make it possible to form a finer resist pattern. For example, the light source wavelength of the exposure apparatus is shortened, and the numerical aperture (NA) of the lens is increased. However, in order to achieve a shorter light source wavelength, there is a problem that an expensive new exposure apparatus is required. Further, when the numerical aperture of the lens is increased, the resolution and the depth of focus are in a trade-off relationship. Therefore, there is a problem that the depth of focus is lowered even if the resolution can be improved.

  Therefore, in recent years, a method called an immersion exposure (liquid immersion lithography) method has been reported as a lithography technique for solving such a problem. This method is a method in which a liquid for immersion exposure (for example, pure water, a fluorine-based inert liquid, or the like) is interposed between the lens and the photoresist film (on the photoresist film) during exposure. According to this method, the exposure optical path space that has been conventionally filled with an inert gas such as air or nitrogen is filled with an immersion exposure liquid having a refractive index (n) larger than that of air or the like. Even when the same exposure light source is used, the same effect as when the light source wavelength of the exposure apparatus is shortened, that is, high resolution can be obtained. In addition, the depth of focus does not decrease.

  Therefore, according to such an immersion exposure method, it is possible to form a resist pattern that is low in cost, excellent in resolution, and also excellent in depth of focus, using a lens mounted on an existing apparatus. it can.

  As the immersion exposure process, for example, in order to protect the photoresist film formed from the radiation-sensitive resin composition, a method of performing immersion exposure after forming an immersion upper layer film on the photoresist film (for example, Patent Document 1) and a method of forming a photoresist film using a radiation-sensitive resin composition containing a polymer containing fluorine atoms in order to eliminate the need for a liquid immersion upper layer film (see, for example, Patent Document 2) ) Has been proposed, and is expected to contribute to an improvement in throughput (that is, an improvement in processing capability).

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

  However, when a radiation-sensitive resin composition containing a polymer containing fluorine atoms as described above is used, the LWR (Line Width Roughness) of the resist pattern after development is deteriorated or the film is reduced. was there. Therefore, development of a radiation-sensitive resin composition capable of forming a photoresist film that has a good LWR after development and hardly causes film loss has been desired.

  The present invention has been made in order to solve the above-described problems of the prior art, and has a radiation-sensitive resin composition capable of forming a photoresist film that has a good LWR after development and is unlikely to cause film loss. An object is to provide a resist pattern forming method using the same.

  As a result of intensive studies to achieve the above-mentioned problems, 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) By using a radiation-sensitive resin composition containing a fluorine atom-containing polymer, it was found that the above-mentioned problems can be achieved, and the present invention has been completed.

  The present invention provides the following radiation-sensitive resin composition and resist pattern forming method.

[1] (A) a repeating unit represented by the following general formula (1) and a polymer having an acid dissociable group (excluding a polymer having a crosslinking group) , and (B) a radiation sensitive acid and generating agent, a polymer (excluding a polymer having a crosslinking group) and, only containing the acid-dissociable group of the polymer (a) containing (C) a fluorine atom, the formula "- C (R) ₃ ”, and in the group represented by the general formula“ —C (R) ₃ ”, any two Rs are bonded to each other, and each is bonded. A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a group derived therefrom is formed together with a carbon atom, 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, and any two of the above R are mutually The radiation-sensitive resin composition in which the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms is an adamantylene group together with the carbon atoms to which each is bonded .

（一般式（１）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^２は、単結合、炭素数１〜５の２価の炭化水素基、アルカンジイルオキシ基、またはアルカンジイルカルボニルオキシ基を示す。Ｒ^３は、３価の有機基を示す。）

(In General Formula (1), 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, or alkanediyl. Represents an oxy group or an alkanediylcarbonyloxy group, and R ³ represents a trivalent organic group.)

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

（一般式（１−１）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^２は、単結合、炭素数１〜５の２価の炭化水素基、アルカンジイルオキシ基、またはアルカンジイルカルボニルオキシ基を示す。Ｒ^５０は、下記一般式（ａ）で表される基、または、下記一般式（ｂ）で表される基を示す。）

(In General Formula (1-1), 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 ⁵⁰ represents a group represented by the following general formula (a) or a group represented by the following general formula (b).

（一般式（ａ）中、ｎ１は０〜２の整数を示す。一般式（ｂ）中、ｎ２〜ｎ５は、それぞれ独立に、０〜２の整数を示す。一般式（ａ）及び一般式（ｂ）中、＊は、一般式（１−１）中のＲ^２に結合する結合手を示す。但し、一般式（ａ）で表される基及び一般式（ｂ）で表される基は、これらの基を構成する炭素原子の少なくとも１つが、酸素原子、窒素原子またはカルボニル基で置換されていてもよい。また、一般式（ａ）で表される基及び一般式（ｂ）で表される基は、置換基を有していてもよい。）

(In General Formula (a), n1 represents an integer of 0 to 2. In General Formula (b), n2 to n5 each independently represents an integer of 0 to 2. General Formula (a) and General Formula In (b), * represents a bond bonded to R ² in the general formula (1-1), provided that the group represented by the general formula (a) and the group represented by the general formula (b). In which at least one of the carbon atoms constituting these groups may be substituted with an oxygen atom, a nitrogen atom or a carbonyl group, and the group represented by the general formula (a) and the general formula (b) The group represented may have a substituent.)

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

（一般式（１−１ａ）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^２は、単結合、炭素数１〜５の２価の炭化水素基、アルカンジイルオキシ基、またはアルカンジイルカルボニルオキシ基を示す。Ｒ^５１は、下記一般式（ａ１）で表される基、または、下記一般式（ｂ１）で表される基を示す。）

(In General Formula (1-1a), 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 ⁵¹ represents a group represented by the following general formula (a1) or a group represented by the following general formula (b1).

（一般式（ａ１）及び一般式（ｂ１）中、＊は、一般式（１−１ａ）中のＲ^２に結合する結合手を示す。）

(In general formula (a1) and general formula (b1), * represents a bond that binds to R ² in general formula (1-1a).)

[4] 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 general formulas (2-1) to (2-3). ] The radiation sensitive resin composition in any one of [3].

（一般式（２−１）〜（２−３）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。一般式（２−１）中、Ｒ^９は炭素数１〜３０のフッ素化アルキル基を示す。一般式（２−２）中、Ｒ^６は、単結合または（ｇ＋１）価の連結基を示し、ｇは１〜３の整数である。一般式（２−３）中、Ｒ^７は２価の連結基を示す。一般式（２−２）及び一般式（２−３）中、Ｒ^８は、水素原子、酸解離性基、またはアルカリ解離性基を示し、Ｒ^１０は、それぞれ独立に、水素原子、フッ素原子、または炭素数１〜１０のフッ素化アルキル基を示す。但し、全てのＲ^１０が水素原子である場合はない。）

(In General Formulas (2-1) to (2-3), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. In General Formula (2-1), R ⁹ represents the number of carbon atoms. 1 to 30 represents a fluorinated alkyl group, R ⁶ in the general formula (2-2) represents a single bond or a (g + 1) -valent linking group, and g represents an integer of 1 to 3. 2-3), R ⁷ represents a divalent linking group, and R ⁸ represents a hydrogen atom, an acid-dissociable group, or an alkali-dissociable group in general formulas (2-2) and (2-3). And each R ¹⁰ independently represents a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 10 carbon atoms, provided that not all R ¹⁰ are hydrogen atoms.)

[5] The polymer (C) is a repeating unit containing at least one group of the group represented by the following general formula (2-4) and the group represented by the following general formula (2-5) (provided that The radiation-sensitive resin composition according to [4], further including a repeating unit represented by the general formula (2-3).

（一般式（２−４）中、Ｒ^１１は、フッ素原子で置換された炭素数１〜１０の炭化水素基を示す。）

(In the general formula (2-4), R ¹¹ represents a C 1-10 hydrocarbon group substituted with a fluorine atom.)

[6] The content of the (C) polymer according to any one of the above [1] to [5], which is 0.1 to 40 parts by mass with respect to 100 parts by mass of the (A) polymer. Radiation sensitive resin composition.

[7] A photoresist film forming step of forming a photoresist film by applying the radiation-sensitive resin composition according to any one of [1] to [6] onto a substrate, and the formed photoresist film An immersion exposure liquid is disposed on the photoresist film, an exposure process for irradiating the photoresist film with radiation through the immersion exposure liquid, and the photoresist film irradiated with the radiation is developed with a developer to form a resist. And a developing step for forming a pattern.

  The radiation-sensitive resin composition of the present invention has an effect that a LWR after development is good and a photoresist film that hardly causes film loss can be formed.

  The resist pattern forming method of the present invention has an effect that a resist pattern with good LWR and less film loss can be formed.

  Hereinafter, although the form for implementing this invention is demonstrated, this invention is not limited to the following embodiment. That is, it is understood that modifications and improvements as appropriate to the following embodiments also belong to the scope of the present invention based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

[1] Radiation sensitive resin composition:
The radiation sensitive resin composition of the present invention comprises (A) a repeating unit represented by the above general formula (1) (hereinafter sometimes referred to as “repeating unit (I)”), and an acid dissociable group. A polymer (hereinafter, sometimes referred to as “(A) polymer”), (B) a radiation-sensitive acid generator (hereinafter, sometimes simply referred to as “(B) acid generator”), (C) a polymer containing a fluorine atom (hereinafter sometimes referred to as “(C) polymer”). According to such a composition, it is possible to form a photoresist film that has a good LWR after development and hardly causes film loss. That is, even when immersion exposure is performed without forming an immersion upper layer film between the photoresist film and the immersion exposure liquid, the photoresist film has a good LWR after development and hardly causes film reduction. Can be formed.

  The radiation sensitive resin composition of the present invention is useful as a chemically amplified resist. Here, the chemically amplified resist is a composition capable of forming a positive resist pattern by the following mechanism. First, an acid is generated from an acid generator by exposure, and an acid dissociable group in the polymer is dissociated by the action of the generated acid to generate a carboxyl group. Next, the exposed portion is dissolved and removed with an alkali developer to form a positive resist pattern. At this time, the exposed part (the part where the polymer in which the acid-dissociable group is dissociated and the carboxyl group is present) has a high solubility in an alkali developer, so that it can be easily absorbed by the alkali developer. Can be dissolved and removed.

In addition, in this specification, the same number is used when showing the same thing among what is shown by " ^Rx " in a general formula.

[1-1] (A) Polymer:
(A) A polymer is a component which has a repeating unit represented by the said General formula (1), and an acid dissociable group, and becomes a base material in the radiation sensitive resin composition of this invention. Here, the “base material” means a component having a film forming ability. Such a polymer (A) is one in which an acid dissociable group is dissociated by the action of an acid and becomes alkali-soluble, and before the acid dissociable group is dissociated, it is insoluble in alkali or hardly soluble in alkali. is there. In the present specification, “alkali insoluble or alkali hardly soluble” means (A) an alkali used when a resist pattern is formed from a photoresist film formed using a radiation-sensitive resin composition containing a polymer. When a film having a film thickness of 100 nm using only the polymer (A) instead of the photoresist film is developed under development conditions, 50% or more of the initial film thickness of the film remains after development.

[1-1-1a] Repeating unit represented by general formula (1):
R ¹ in the general formula (1) is preferably a hydrogen atom, a methyl group, or a trifluoromethyl group.

Examples of the divalent hydrocarbon group having 1 to 5 carbon atoms represented by R ² in the general formula (1) include a linear or branched divalent hydrocarbon group having 1 to 5 carbon atoms. it can. Specifically, methylene group, ethylene group, 1,3-propylene group, 1,2-propylene group, 2,2-propylene group, 1,4-butylene group, 1,3-butylene group, 1,2- And a butylene group.

Examples of the alkanediyloxy group represented by R ² in the general formula (1) include a group in which a divalent hydrocarbon group having 1 to 5 carbon atoms and an oxygen atom are bonded. Examples of the divalent hydrocarbon group having 1 to 5 carbon atoms include a methylene group, an ethylene group, a 1,3-propylene group, a 1,2-propylene group, a 2,2-propylene group, and a 1,4-butylene group. 1,3-butylene group, 1,2-butylene group and the like.

Examples of the alkanediylcarbonyloxy group represented by R ² in the general formula (1) include a group in which a divalent hydrocarbon group having 1 to 5 carbon atoms and a carbonyloxy group are bonded. Examples of the divalent hydrocarbon group having 1 to 5 carbon atoms include a methylene group, an ethylene group, a 1,3-propylene group, a 1,2-propylene group, a 2,2-propylene group, and a 1,4-butylene group. 1,3-butylene group, 1,2-butylene group and the like.

In the general formula (1), R ³ represents a trivalent organic machine, specifically, a trivalent chain hydrocarbon group, a trivalent group having a cyclic hydrocarbon structure, or a 3 having a heterocyclic structure. Valent groups and the like. 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 general formula (1) include the repeating unit represented by the general formula (1-1), and among the repeating units represented by the general formula (1-1). The repeating unit represented by the general formula (1-1a) can be given as a preferred example. When the repeating unit is represented by the general formula (1-1a), it is possible to form a photoresist film that has a better LWR after development and is less likely to cause film loss.

In addition, as described above, R ⁵⁰ in the general formula (1-1) and R ⁵¹ in the general formula (1-1a) represent one of carbon atoms constituting these groups as an oxygen atom, a nitrogen atom, or a carbonyl group. Or 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 the repeating units represented by the following general formulas (3-1) to (3-21). Among these, from the viewpoint of obtaining a radiation-sensitive resin composition capable of forming a photoresist film that has an even better LWR after development and is unlikely to cause film loss, the following general formula (3-1) And a repeating unit represented by the following general formula (3-9) are preferred. In the following general formulas (3-1) to (3-21), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group.

Of the repeating units represented by the general formulas (3-1) to (3-21), the general formulas (3-1) to (3-16) are represented by the general formula (1-1). This corresponds to the repeating unit and the repeating unit represented by the general formula (1-1a). In particular, in the repeating units represented by the general formulas (3-4) to (3-7), R ⁵⁰ in the general formula (1-1) and the general formula (1-1a) has a substituent. That is, it is a repeating unit corresponding to (when the group represented by the general formula (a) has a substituent). The repeating unit represented by the general formulas (3-11) and (3-12) is a repeating unit corresponding to the case where the group represented by the general formula (b) has a substituent. Specifically, one of carbon atoms constituting R ⁵⁰ is substituted with 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 general formula (b) has a substituent. In this, one of carbon atoms constituting R ⁵⁰ is substituted with an oxygen atom, a nitrogen atom or a carbonyl group, and has a substituent.

  In addition, the monomer for forming the repeating unit (I) can be synthesized by a conventionally known method, specifically, 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 unit (a):
(A) The polymer may have another repeating unit (a) in addition to the repeating unit represented by the general formula (1). Examples of other repeating units (a) include the repeating units (II) to (VI) shown below.

[1-1-1b-1] Repeating unit (II):
Examples of the repeating unit (II) include repeating units represented by the following general formulas (4-1) to (4-7).

（一般式（４−１）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^１２〜Ｒ^１４は、相互に独立に、炭素数１〜４の直鎖状若しくは分岐状のアルキル基、または炭素数４〜２０の１価の脂環式炭化水素基を示す。また、Ｒ^１３とＲ^１４とが相互に結合して炭素数４〜２０の２価の脂環式炭化水素基またはその誘導体を形成してもよい。）

(In General Formula (4-1), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. R ^{12 to} R ¹⁴ are each independently a straight chain having 1 to 4 carbon atoms. Or a branched alkyl group, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, and R ¹³ and R ¹⁴ are bonded to each other to form a divalent hydrocarbon group having 4 to 20 carbon atoms. An alicyclic hydrocarbon group or a derivative thereof may be formed.)

In General Formulas (4-2) to (4-7), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. In General 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 general formulas (4-5) and (4-6), R ¹⁶ independently represents a hydrogen atom or a methoxy group. In the general formulas (4-3) and (4-4), R ¹⁷ each independently represents a single bond or a methylene group, and each m independently represents 0 or 1. In the general formulas (4-4) and (4-6), R ¹⁸ each independently represents an oxygen atom or a methylene group.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ^{12 to} R ¹⁴ in the general formula (4-1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and an n-butyl group. , 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

A monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^{12 to} R ¹⁴ in the general formula (4-1), and R ¹³ and R ¹⁴ are bonded to each other to bond each other. Examples of the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms that are formed together with the carbon atom being used include a bridged skeleton such as an adamantane skeleton, a norbornane skeleton, a tricyclodecane skeleton, and a tetracyclododecane skeleton. Or a group having a cycloalkane skeleton such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane; these groups are, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group 1 or more of linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms such as 2-methylpropyl group, 1-methylpropyl group and t-butyl group In those groups having an alicyclic skeleton such substituted groups.

  Among 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, Those having a cyclooctyl skeleton are preferred.

Specific examples of “—CR ¹² R ¹³ R ¹⁴ ” in the general formula (4-1) include a t-butyl group, a 1-n- (1-ethyl-1-methyl) propyl group, and a 1-n. -(1,1-dimethyl) propyl group, 1-n- (1,1-dimethyl) butyl group, 1-n- (1,1-dimethyl) pentyl group, 1- (1,1-diethyl) propyl group 1-n- (1,1-diethyl) butyl group, 1-n- (1,1-diethyl) pentyl group, 1- (1-methyl) cyclopentyl group, 1- (1-ethyl) cyclopentyl group, 1 -(1-n-propyl) cyclopentyl group, 1- (1-i-propyl) cyclopentyl group, 1- (1-methyl) cyclohexyl group, 1- (1-ethyl) cyclohexyl group, 1- (1-n- Propyl) cyclohexyl group, 1- (1-i-propyl) cyclohexyl Sil group, 1- {1-methyl-1- (2-norbornyl)} ethyl group, 1- {1-methyl-1- (2-tetracyclodecanyl)} ethyl group, 1- {1-methyl-1 -(1-adamantyl)} ethyl group, 2- (2-methyl) norbornyl group, 2- (2-ethyl) norbornyl group, 2- (2-n-propyl) norbornyl group, 2- (2-i-propyl) ) Norbornyl group, 2- (2-methyl) tetracyclodecanyl group, 2- (2-ethyl) tetracyclodecanyl group, 2- (2-n-propyl) tetracyclodecanyl group, 2- (2- i-propyl) tetracyclodecanyl group, 2- (2-methyl) adamantyl group, 2- (2-ethyl) adamantyl group, 2- (2-n-propyl) adamantyl group, 2- (2-i-propyl) Adamantyl groups and these A group consisting of a cyclic ring is, for example, a carbon such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group, or a t-butyl group. Examples thereof include a group substituted with one or more linear or branched or cyclic alkyl groups of 1 to 4 or more.

Examples of the monomer for forming the repeating unit (II) include (meth) acrylic acid 2-methyladamantyl-2-yl ester and (meth) acrylic acid 2-methyl-3-hydroxyadamantyl-2-yl. Ester, (meth) acrylic acid 2-ethyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyl-3-hydroxyadamantyl-2-yl ester, (meth) acrylic acid 2-n-propyladamantyl-2-yl ester Yl ester, (meth) acrylic acid 2-isopropyladamantyl-2-yl ester, (meth) acrylic acid-2-methylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-2- Ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-8-methyltricyclo [5. .1.0 ^2,6] decan-8-yl ester, (meth) ethyl-8-acrylic acid tricyclo [5.2.1.0 ^2,6] decan-8-yl ester,

(Meth) acrylic acid-4-methyltetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl ester, (meth) acrylic acid-4-ethyltetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept-2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tetracyclo [6.2.1 ^3,6.0 0.0 ^2,7 ] dodecane -4-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1- (3-hydroxyadamantan-1-yl) -1-methyl ethyl ester, (meth) acrylic acid 1,1-dicyclohexylethyl ester, (meth) acrylic acid 1,1-di (bicyclo [2.2.1] hept-2-yl) ethyl ester, Meth) acrylic acid 1,1-di (tricyclo [5.2.1.0 ^2,6] decan-8-yl) ethyl ester, (meth) acrylic acid 1,1-di (tetracyclo [6.2.1 ^3,6 .0 ^2,7] dodecane-4-yl) ethyl ester, (meth) acrylic acid 1,1-di (adamantan-1-yl) ethyl ester, (meth) acrylic acid 1-methyl-1-cyclopentyl Examples include esters, (meth) acrylic acid 1-ethyl-1-cyclopentyl ester, (meth) acrylic acid 1-methyl-1-cyclohexyl ester, (meth) acrylic acid 1-ethyl-1-cyclohexyl ester, and the like.

  Among these monomers, (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyladamantyl-2-yl ester, (meth) acrylic acid-2-methylbicyclo [2 2.1] hept-2-yl ester, (meth) acrylic acid-2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid 1- (bicyclo [2.2. 1] hept-2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1-methyl-1-cyclopentyl ester, (Meth) acrylic acid 1-ethyl-1-cyclopentyl ester, (meth) acrylic acid 1-methyl-1-cyclohexyl ester, (meth) acrylic acid 1-e -1-cyclohexyl ester.

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

  The content ratio of the repeating unit (II) is preferably 15 to 85 mol%, more preferably 25 to 75 mol%, when the total repeating unit of the polymer (A) is 100 mol%, It is especially preferable that it is 35-60 mol%. When the content is less than 15 mol%, the contrast after dissolution (that is, the contrast between the portion dissolved in the developer and the portion not dissolved) is impaired, and the pattern shape is reduced (that is, the cross section is rectangular). A resist pattern cannot be obtained). On the other hand, if it exceeds 85 mol%, sufficient adhesion with the substrate cannot be obtained, and the resulting resist pattern may be peeled off from the substrate.

[1-1-1b-2] Repeating unit (III):
Of the other repeating units (a), the repeating unit (III) is a repeating unit derived from the monomer shown below. That is, examples of the monomer include (meth) acrylic acid-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid. -9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid-5-oxo-4-oxa-tricyclo [ 5.2.1.0 ^3,8 ] dec-2-yl ester, (meth) acrylic acid-10-methoxycarbonyl-5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 ] Non-2-yl ester, (meth) acrylic acid-6-oxo-7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-4-methoxycarbonyl-6-oxo -7-oxa-bicyclo 3.2.1] Oct-2-yl ester, (meth) acrylic acid-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, (meth) acrylic acid-4- Methoxycarbonyl-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester,

  (Meth) acrylic acid-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-methyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-ethyl-2- Oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-propyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic Acid-2,2-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxotetrahydrofuran -3-yl ester, (meth) acrylic acid-4,4-dimethyl-2-oxo Trahydrofuran-3-yl ester, (meth) acrylic acid-5,5-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) Acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-3,3-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-4,4-dimethyl-5 -Oxotetrahydrofuran-2-ylmethyl ester and the like can be mentioned.

  The content ratio of the repeating unit (III) is preferably 10 to 50 mol%, more preferably 20 to 40 mol%, when the total repeating unit of the polymer (A) is 100 mol%. If the content is less than 10 mol%, the adhesion to the substrate may be insufficient and the pattern may be peeled off. On the other hand, if it exceeds 50 mol%, the solubility in an alkali developer may be insufficient and development defects may increase.

[1-1-1b-3] Repeating unit (IV):
Examples of the repeating unit (IV) among the other repeating units (a) include a repeating unit having an alicyclic hydrocarbon group.

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

（一般式（５）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^１９は、炭素数４〜２０の脂環式炭化水素基を示す。）

(In General Formula (5), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. 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 the general formula (5) include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, and bicyclo [2. 2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tetracyclo [6.17 ^3,6 . And hydrocarbon groups composed of alicyclic rings derived from cycloalkanes such as 0 ^2,7 ] dodecane and tricyclo [3.3.1.1 ^3,7 ] decane.

  These cycloalkane-derived alicyclic rings may have a substituent, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group. , 1-methylpropyl group, t-butyl group and the like, may be substituted with one or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms. These are not limited to those substituted with the above alkyl group, but may be those substituted with a hydroxyl group, a cyano group, a hydroxyalkyl group having 1 to 10 carbon atoms, a carboxyl group, or oxygen.

Examples of the monomer for forming the repeating unit (IV) include (meth) acrylic acid-bicyclo [2.2.1] hept-2-yl ester and (meth) acrylic acid-bicyclo [2.2. .2] Oct-2-yl ester, (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 ] dodec-9-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] dec-1-yl ester, (meth) acrylic acid-tricyclo [3.3. ^1.1,7 ] dec-2-yl ester and the like.

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

[1-1-1b-4] Repeating unit (V):
Among the other repeating units (a), examples of the repeating unit (V) include repeating units represented by the following general formula (6).

（一般式（６）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^２０は、２価の有機基を示す。）

(In General Formula (6), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. R ²⁰ represents a divalent organic group.)

The divalent organic group represented by R ²⁰ in the general formula (6) is preferably a divalent hydrocarbon group, more preferably a chain or cyclic hydrocarbon group, and even an alkylene glycol group. It may be an alkylene ester group.

Specific examples of the divalent organic group represented by R ²⁰ include a methylene group, an ethylene group, a 1,3-propylene group or a propylene group such as a 1,2-propylene group, a tetramethylene group, a pentamethylene group, Hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptacamethylene group Group, octadecamethylene group, nonacamethylene group, insalene group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl -1,4-butylene group, 2-methyl-1,4-butylene group, methylidene group, ethylidene group, propylidene group Or a saturated chain hydrocarbon group such as a 2-propylidene group, a cyclobutylene group such as a 1,3-cyclobutylene group, a cyclopentylene group such as a 1,3-cyclopentylene group, 1,4- Monocyclic hydrocarbon ring groups such as cycloalkylene groups having 3 to 10 carbon atoms such as cyclohexylene groups such as cyclohexylene groups, cyclooctylene groups such as 1,5-cyclooctylene groups, 1,4-norbornylene groups Or a hydrocarbon ring group having 2 to 4 cyclic carbon atoms such as a norbornylene group such as 2,5-norbornylene group, an adamantylene group such as 1,5-adamantylene group, 2,6-adamantylene group, etc. And a crosslinked cyclic hydrocarbon ring group.

In the case where R ²⁰ contains a divalent aliphatic cyclic hydrocarbon group, a C 1 -C 1 as a spacer between the bistrifluoromethyl-hydroxy-methyl group and the divalent aliphatic cyclic hydrocarbon group. It is preferable to arrange 4 alkylene groups. ^The divalent organic group represented by ^{R 20,} a hydrocarbon group containing 2,5-norbornylene group, 1,2-ethylene group, a propylene group is preferable.

Examples of the monomer for forming the repeating unit (V) include (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester, ( (Meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl) -2-hydroxy-5-pentyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, (meth) acrylic acid 2- { [5- (1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl} ester, (meth) acrylic 3 - {[8- (1 ', 1', 1'-trifluoro-2'-trifluoromethyl-2'-hydroxy) propyl] tetracyclo ^{[6.17 3,6.} 0 ^2,7 ] dodecyl} ester and the like.

  The content ratio of the repeating unit (V) is preferably 30 mol% or less, and more preferably 25 mol% or less, when the total repeating unit of the polymer (A) is 100 mol%. When the content is more than 30 mol%, the formed photoresist film may be easily swollen by an alkali developer.

[1-1-1b-5] Repeating unit (VI):
Among the other repeating units (a), examples of the repeating unit (VI) include repeating units derived from aromatic compounds.

  Examples of the monomer for forming a repeating unit derived from an aromatic compound include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-methoxystyrene, 3- Methoxystyrene, 4-methoxystyrene, 4- (2-t-butoxycarbonylethyloxy) styrene 2-hydroxystyrene, 3-hydroxystyrene, 4-hydroxystyrene, 2-hydroxy-α-methylstyrene, 3-hydroxy-α -Methylstyrene, 4-hydroxy-α-methylstyrene, 2-methyl-3-hydroxystyrene, 4-methyl-3-hydroxystyrene, 5-methyl-3-hydroxystyrene, 2-methyl-4-hydroxystyrene, 3 -Methyl-4-hydroxystyrene, 3,4-dihydroxystyrene 2,4,6-trihydroxystyrene, 4-t-butoxystyrene, 4-t-butoxy-α-methylstyrene, 4- (2-ethyl-2-propoxy) styrene, 4- (2-ethyl- 2-propoxy) -α-methylstyrene, 4- (1-ethoxyethoxy) styrene, 4- (1-ethoxyethoxy) -α-methylstyrene, phenyl (meth) acrylate, benzyl (meth) acrylate, acenaphthylene, 5-hydroxyacenaphthylene, 1-vinylnaphthalene, 2-vinylnaphthalene, 2-hydroxy-6-vinylnaphthalene, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, 1-naphthylmethyl (meth) acrylate 1-anthryl (meth) acrylate, 2-anthryl (meth) acrylate, 9-anthryl Examples include ru (meth) acrylate, 9-anthrylmethyl (meth) acrylate, and 1-vinylpyrene.

  The content of the repeating unit (VI) is preferably 40 mol% or less, and more preferably 30 mol% or less when the total repeating unit (A) is 100 mol%. When the content ratio is more than 40 mol%, the transmittance of the radiation in the formed photoresist film is lowered, so that the pattern profile may be deteriorated (the pattern shape after development does not become rectangular).

  In addition, each said repeating unit (II)-(VI) may be contained individually by 1 type, respectively, and may be contained 2 or more types.

[1-1-2] Acid-dissociable group:
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 dissociates in the presence of an acid. As such an acid dissociable group, specifically, t-butoxycarbonyl group, tetrahydropyranyl group, tetrahydrofuranyl group, (thiotetrahydropyranylsulfanyl) methyl group, (thiotetrahydrofuranylsulfanyl) methyl group, Examples include an alkoxy-substituted methyl group and an alkylsulfanyl-substituted methyl group. In addition, as an alkoxyl group (substituent) in an alkoxy substituted methyl group, there exists a C1-C4 alkoxyl group, for example. Examples of the alkyl group (substituent) in the alkylsulfanyl-substituted methyl group include an alkyl group having 1 to 4 carbon atoms.

Furthermore, examples of the acid dissociable group include a group represented by the general formula “—C (R) ₃ ”. Note that three R's are each independently 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 R are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a group derived therefrom with the carbon atom to which each R is bonded. The remaining one R represents a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a group 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 general formula “—C (R) ₃ ” include a methyl group, an ethyl group, and n-propyl. Group, i-propyl group, n-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 general formula “—C (R) ₃ ” include norbornane, tricyclodecane, and tetracyclododecane. And a group consisting of an alicyclic ring derived from cycloalkanes such as adamantane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane. And as a group induced | guided | derived from the said alicyclic hydrocarbon group, the above-mentioned monovalent alicyclic hydrocarbon group is a methyl group, an ethyl group, n-propyl group, i-propyl group, n-, for example. A group substituted with one or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as butyl group, 2-methylpropyl group, 1-methylpropyl group and t-butyl group. And so on.

  Among these, the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R is composed of an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane. An alicyclic hydrocarbon group and a group obtained by substituting this alicyclic hydrocarbon group with an alkyl group are preferred.

Any two Rs represented by R in the group represented by the general formula “—C (R) ₃ ” are bonded to each other and bonded to each other (bonded to an oxygen atom). Examples of the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms formed with a carbon atom) are monocyclic such as a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cyclooctylene group, and the like. Examples thereof include a hydrocarbon group, a norbornylene group, a tricyclodecanylene group, a polycyclic hydrocarbon group such as a tetracyclodecanylene group, and a bridged polycyclic hydrocarbon group such as an adamantylene group.

And any two R shown by R in group represented by general formula "-C (R) ₃ " mutually couple | bonds, and C4-C20 with each carbon atom which each has couple | bonded. As the group derived from the divalent alicyclic hydrocarbon group, for example, the above-mentioned divalent alicyclic hydrocarbon group includes, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n -Substituted with one or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as -butyl group, 2-methylpropyl group, 1-methylpropyl group and t-butyl group Examples include groups.

  Among these, a monocyclic hydrocarbon group such as a cyclopentylene group or a cyclohexylene group, or a group obtained by substituting this divalent alicyclic hydrocarbon group (monocyclic hydrocarbon group) with an alkyl group. preferable.

Here, specific examples of the group represented by the general formula “—C (R) ₃ ” include a t-butyl group, a 1-n- (1-ethyl-1-methyl) propyl group, and a 1-n. -(1,1-dimethyl) propyl group, 1-n- (1,1-dimethyl) butyl group, 1-n- (1,1-dimethyl) pentyl group, 1- (1,1-diethyl) propyl group 1-n- (1,1-diethyl) butyl group, 1-n- (1,1-diethyl) pentyl group, 1- (1-methyl) cyclopentyl group, 1- (1-ethyl) cyclopentyl group, 1 -(1-n-propyl) cyclopentyl group, 1- (1-i-propyl) cyclopentyl group, 1- (1-methyl) cyclohexyl group, 1- (1-ethyl) cyclohexyl group, 1- (1-n- Propyl) cyclohexyl group, 1- (1-i-propyl) cyclohexyl 1- {1-methyl-1- (2-norbornyl)} ethyl group, 1- {1-methyl-1- (2-tetracyclodecanyl)} ethyl group, 1- {1-methyl-1- ( 1-adamantyl)} ethyl group, 2- (2-methyl) norbornyl group, 2- (2-ethyl) norbornyl group, 2- (2-n-propyl) norbornyl group, 2- (2-i-propyl) norbornyl Group, 2- (2-methyl) tetracyclodecanyl group, 2- (2-ethyl) tetracyclodecanyl group, 2- (2-n-propyl) tetracyclodecanyl group, 2- (2-i- Propyl) tetracyclodecanyl group, 1- (1-methyl) adamantyl group, 1- (1-ethyl) adamantyl group, 1- (1-n-propyl) adamantyl group, 1- (1-i-propyl) adamantyl group Groups and groups consisting of these alicyclic rings For example, a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, etc. Examples thereof include a group substituted with one or more chain, branched or cyclic alkyl groups.

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

[1-1-3] Fluorine atom content ratio:
(A) The polymer may or may not contain a fluorine atom, but when it contains a fluorine atom, (C) a fluorine atom rather than the content of fluorine atoms in the polymer. The content ratio of is low. (A) The content ratio of fluorine atoms in the polymer is usually less than 5% by mass, preferably 0 to 4.9% by mass, when the total amount of (A) polymer is 100% by mass. 0 to 4.0% by mass is even more preferable. (A) When the content rate of the fluorine atom in a polymer is smaller than (C) polymer, (C) polymer tends to be unevenly distributed in the photoresist film surface layer. Accordingly, it is possible to increase the water repellency of the surface layer portion of the photoresist film to be formed, and it is possible to form a photoresist film having good water repellency without separately forming an immersion upper layer film during immersion exposure. There are advantages. In addition, it is preferable that the difference of the fluorine atom content rate of (A) polymer and (C) polymer is 1 mass% or more. When the difference is 1% by mass or more, the polymer (C) is likely to be unevenly distributed on the surface 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 including the polymer (C) described later. Specifically, when the polymer (A) contains a fluorine atom, as described above, the content ratio of the fluorine atom in the polymer (A) is more than the content ratio of the fluorine atom in the polymer (C). Is also small. When the content ratio of fluorine atoms is smaller in the polymer (A) than in the polymer (C), the photoresist film is formed due to the oil repellency of the polymer (C) when the photoresist film is formed. There is a tendency for the distribution of the polymer (C) to increase on the surface. That is, (C) the polymer is unevenly distributed on the surface of the photoresist film (side on which the immersion exposure liquid is disposed). Therefore, it is not necessary to separately form an upper layer film for the purpose of blocking the photoresist film from the immersion medium, and can be suitably used for the immersion exposure method. Here, in this specification, the content rate of a fluorine atom is the value measured by < ¹³ > C-NMR.

  (A) Although the weight average molecular weight (Mw) by the gel permeation chromatography (GPC) method of a polymer is not specifically limited, It is preferable that it is 1,000-100,000, and is 1,000-30,000. Is more preferable, and it is especially preferable that it is 1,000-20,000. If the Mw is less than 1,000, the heat resistance of the formed photoresist film may be reduced. On the other hand, if it exceeds 100,000, the developability of the formed photoresist film may be lowered. Moreover, ratio (Mw / Mn) of Mw and the number average molecular weight (Mn) by GPC method is 1-5 normally, and it is preferable that it is 1-3.

  In addition, the content ratio in terms of solid content of the low molecular weight component derived from the monomer used in preparing the polymer (A) in the polymer (A) is 100% by mass of the total amount of the polymer (A). In this case, it is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, and particularly preferably 0.05% by mass or less. When the content is 0.1% by mass or less, it is possible to reduce the amount of eluate that is eluted into the liquid for immersion exposure during the immersion exposure. Furthermore, the generation of foreign matters during storage can be prevented, and the occurrence of coating unevenness during coating can be prevented, so that the occurrence of defects during formation of a resist pattern can be sufficiently suppressed.

  The monomer-derived low molecular weight component is a component having an Mw of 500 or less, and examples thereof include a monomer, a dimer, a trimer, and an oligomer. Examples of a method for removing the component having an Mw of 500 or less (that is, (A) polymer purification method) include, for example, chemical purification methods such as water washing and liquid-liquid extraction, and these chemical purification methods, ultrafiltration, and centrifugation. Examples thereof include a method in combination with a physical purification method such as separation. In addition, the low molecular weight component derived from the said monomer in (A) polymer can be detected by a high performance liquid chromatography (HPLC).

  Furthermore, (A) a polymer is so preferable that there is little content of impurities, such as a halogen and a metal. When the content of the impurities is small, the sensitivity, resolution, and process stability of the formed photoresist film can be further improved, and a good resist pattern shape can be obtained.

  (A) The polymer is, for example, a monomer (polymerizable unsaturated monomer) for forming each repeating unit described above, hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds. It can manufacture by superposing | polymerizing in a suitable solvent in presence of a chain transfer agent as needed using radical polymerization initiators.

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

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

[1-2] (B) Radiation sensitive acid generator:
(B) The radiation-sensitive acid generator generates acid upon irradiation with light such as radiation (hereinafter sometimes referred to as “exposure”). And the acid dissociable group which exists in (A) polymer is dissociated from (A) polymer by the effect | action of the acid generated from (B) acid generator by exposure. The polymer (A) from which the acid dissociable group has been dissociated becomes alkali-soluble. That is, the exposed portion of the photoresist film becomes readily soluble in the alkaline developer. Therefore, a positive resist pattern can be formed by developing with an alkaline developer. Examples of the acid generator (B) include compounds described in paragraphs [0080] to [0113] of JP2009-134088A.

  (B) Specific examples of the acid generator include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, and bis (4-t-butylphenyl) iodonium. Trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium Nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, cyclohexyl 2-oxocyclohexyl Le methyl trifluoromethanesulfonate, dicyclohexyl-2-oxo-cyclohexyl trifluoromethane sulfonate, 2-oxo-cyclohexyl dimethyl sulfonium trifluoromethane sulfonate, 4-hydroxy-1-naphthyl dimethyl sulfonium trifluoromethane sulfonate,

  4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium nonafluoro-n-butanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium perfluoro-n- Octanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (1-naphthylacetomethyl) Tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- 3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro -n- butane sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro -n- octane sulfonate,

  Trifluoromethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide , Perfluoro-n-octanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, N-hydroxysuccinimide nonafluoro-n- Butanesulfonate, N-hydroxysuccinimide perfluoro-n-octanesulfonate, and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate are preferred. In addition, (B) acid generator can be used individually by 1 type or in combination of 2 or more types.

  The content of the (B) acid generator is preferably 0.1 to 30 parts by mass, more preferably 2 to 27 parts by mass, with respect to 100 parts by mass of the (A) polymer. Particularly preferred is 25 parts by mass. There exists a possibility that the sensitivity and resolution of the formed photoresist film may fall that the said content is less than 0.1 mass part. On the other hand, if it exceeds 30 parts by mass, the applicability and pattern shape of the formed photoresist film may be deteriorated.

[1-3] (C) Polymer:
(C) A polymer is a component contained as a polymer additive in the radiation-sensitive resin composition of the present invention, and is a polymer containing a fluorine atom. By including such a polymer, the water repellency of the formed photoresist film is improved, and there is an advantage that it is not necessary to form an immersion upper film in the immersion exposure process. Moreover, by including (A) polymer and (C) polymer, (C) polymer is unevenly distributed in the photoresist film surface layer, and favorable water repellency is obtained.

  The polymer (C) is not particularly limited as long as it contains a fluorine atom in the molecule, as described above, but the repeating unit represented by the following general formula (2-1) (hereinafter referred to as “repeating unit (2-1)”. ) "), A repeating unit represented by the following general formula (2-2) (hereinafter may be referred to as" repeating unit (2-2) "), and a general formula (2- It is preferable to have at least one repeating unit selected from the group consisting of the repeating units represented by 3) (hereinafter sometimes referred to as “repeating units (2-3)”). By having these repeating units, it is possible to suppress the (B) acid generator, acid diffusion control agent, and the like in the photoresist film from being eluted into the immersion exposure liquid. Furthermore, since the receding contact angle between the photoresist film and the immersion exposure liquid is improved (increased), water droplets derived from the immersion exposure liquid hardly remain on the photoresist film, and immersion exposure is performed. It is possible to suppress the occurrence of defects due to.

（一般式（２−１）〜（２−３）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。一般式（２−１）中、Ｒ^９は炭素数１〜３０のフッ素化アルキル基を示す。一般式（２−２）中、Ｒ^６は、単結合または（ｇ＋１）価の連結基を示し、ｇは１〜３の整数である。一般式（２−３）中、Ｒ^７は２価の連結基を示す。一般式（２−２）及び一般式（２−３）中、Ｒ^８は、水素原子、酸解離性基、またはアルカリ解離性基を示し、Ｒ^１０は、それぞれ独立に、水素原子、フッ素原子、または炭素数１〜１０のフッ素化アルキル基を示す。但し、全てのＲ^１０が水素原子である場合はない。）

(In General Formulas (2-1) to (2-3), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. In General Formula (2-1), R ⁹ represents the number of carbon atoms. 1 to 30 represents a fluorinated alkyl group, R ⁶ in the general formula (2-2) represents a single bond or a (g + 1) -valent linking group, and g represents an integer of 1 to 3. 2-3), R ⁷ represents a divalent linking group, and R ⁸ represents a hydrogen atom, an acid-dissociable group, or an alkali-dissociable group in general formulas (2-2) and (2-3). And each R ¹⁰ independently represents a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 10 carbon atoms, provided that not all R ¹⁰ are hydrogen atoms.)

[1-3-1] Repeating unit represented by formula (2-1):
Examples of the lower alkyl group represented by R ¹ in the general formula (2-1) include a methyl group. Examples of the halogenated lower alkyl group represented by R ¹ in the general formula (2-1) include a trifluoromethyl group.

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

  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, 1 -Butyl group, 2-butyl group, 2- (2-methylpropyl) group, 1-pentyl group, 2-pentyl group, 3-pentyl group, 1- (2-methylbutyl) group, 1- (3-methylbutyl) Group, 2- (2-methylbutyl) group, 2- (3-methylbutyl) group, neopentyl group, 1-hexyl group, 2-hexyl group, 3-hexyl group, 1- (2-methylpentyl) group, 1- (3-methylpentyl) group, 1- (4-methylpentyl) group, 2- (2-methylpentyl) group, 2- (3-methylpentyl) group, 2- (4-methylpentyl) group, 3- (2-methylpentyl) group, 3- (3 Such as linear or branched partially fluorinated or perfluoroalkyl group of the alkyl group, such as methylpentyl) group and the like.

  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, 1- (1 -Cyclopentylethyl) group, 1- (2-cyclopentylethyl) group, cyclohexyl group, cyclohexylmethyl group, 1- (1-cyclohexylethyl) group, 1- (2-cyclohexylethyl group), cycloheptyl group, cycloheptylmethyl A partially fluorinated or perfluoroalkyl group of an alicyclic alkyl group such as a group, 1- (1-cycloheptylethyl) group, 1- (2-cycloheptylethyl) group, and 2-norbornyl group. .

  Examples of the monomer for forming the repeating unit represented by the general formula (2-1) include trifluoromethyl (meth) acrylic acid ester and 2,2,2-trifluoroethyl (meth) acrylic acid. Ester, perfluoroethyl (meth) acrylic acid ester, perfluoro n-propyl (meth) acrylic acid ester, perfluoro i-propyl (meth) acrylic acid ester, perfluoro n-butyl (meth) acrylic acid ester, perfluoro i-butyl (meth) acrylic acid ester, perfluoro t-butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylic acid ester, 1- (2,2,3,3,4,4,5,5-octafluoropentyl) (meth) acrylic acid ester, perfluoro Chlohexylmethyl (meth) acrylic acid ester, 1- (2,2,3,3,3-pentafluoropropyl) (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 ester, 1- (5-trifluoromethyl-3,3,4,4, 5,6,6,6-octafluorohexyl) (meth) acrylic acid ester and the like.

  The content ratio of the repeating unit (2-1) is preferably 20 to 90 mol%, preferably 20 to 80 mol%, when the total repeating unit of the polymer (C) is 100 mol%. Further preferred is 20 to 70 mol%. When the content ratio is within the above range, there is an advantage that the balance between water repellency and affinity for the developer in the formed photoresist film becomes good.

[1-3-2] Repeating unit represented by formula (2-2):
Specific examples of the (g + 1) -valent linking group represented by R ⁶ in the general formula (2-2) include (g + 1) -valent hydrocarbon groups having 1 to 30 carbon atoms, and hydrocarbons thereof. And a structure in which a group is combined with an oxygen atom, a sulfur atom, an imino group, a carbonyl group, —CO—O—, or —CO—NH—. And g is an integer of 1-3, and when g is 2 or 3, the structure represented by the following general formula (2-2a) in General formula (2-2) is mutually independent.

Of the hydrocarbon groups having 1 to 30 carbon atoms and a (g + 1) valence, R ⁶ having a chain structure includes, for example, methane, ethane, propane, butane, 2-methylpropane, pentane, 2-methylbutane, 2, A structure obtained by removing (g + 1) hydrogen atoms from a chain hydrocarbon having 1 to 10 carbon atoms such as 2-dimethylpropane, hexane, heptane, octane, nonane and decane can be given.

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

As for the structure of R ^{6, a combination} of a hydrocarbon group and an oxygen atom, sulfur atom, imino group, carbonyl group, —CO—O— or —CO—NH— is, for example, a structure represented by the following general formula: And so on. In the following general formula, each R ²¹ independently represents a single bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms, a divalent cyclic hydrocarbon group having 4 to 20 carbon atoms, or 6 carbon atoms. ~ 30 represents a divalent aromatic hydrocarbon group. g is an integer of 1-3.

Examples of the divalent chain hydrocarbon group having 1 to 10 carbon atoms and represented by R ²¹ in the above general formula include methane, ethane, propane, butane, 2-methylpropane, pentane, 2-methylbutane, 2 , 2-dimethylpropane, hexane, 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, and tricyclo [5.2. And a group derived from .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, 1 Examples thereof include linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as -methylpropyl group and t-butyl group.

Examples of the acid dissociable group represented by R ⁸ in the general formula (2-2) include the same acid dissociable groups in the above-described (A) polymer. When having such an acid dissociable group, the solubility of the polymer (C) present in the exposed portion can be improved. This is considered to be because the acid generated in the exposure step in the resist pattern forming method described later reacts with the acid dissociable group of the (C) polymer to produce a polar group.

The alkali dissociable group represented by R ⁸ in the general 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, A group that dissociates in the presence. Such an alkali dissociable group is not particularly limited as long as it exhibits the above properties, and examples thereof include a group represented by the following general formula (2-2a1).

（一般式（２−２ａ１）中、Ｒ^２２は、少なくとも一つの水素原子がフッ素原子に置換された、炭素数が１〜１０の炭化水素基を示す。）

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

R ²² in the general formula (2-2a1) is preferably a linear or branched perfluoroalkyl group having 1 to 10 carbon atoms in which all of the hydrogen atoms of the hydrocarbon group are substituted with fluorine atoms. More preferred is a fluoromethyl group.

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

（一般式（７−１）及び（７−２）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示し、Ｒ^２４は、水素原子、酸解離性基、またはアルカリ解離性基を示す。一般式（７−１）中、Ｒ^２３は（ｇ＋１）価の連結基を示す。一般式（７−２）中、ｇは１〜３の整数である。）

(In the general formulas (7-1) and (7-2), 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. Represents a dissociable group, R ²³ represents a (g + 1) -valent linking group in General Formula (7-1), and g is an integer of 1 to 3 in General Formula (7-2).

Specifically, the compound for forming the repeating unit represented by the general formula (7-1) and the repeating unit represented by the following general formula (7-2) is represented by the following general formula. And the like. In the following general 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 in which R ²⁴ in the above general formula is an acid-dissociable group or an alkali-dissociable group can be obtained from a compound in which R ²⁴ is a hydrogen atom in each general formula. Specifically, when synthesizing a compound in which R ²⁴ is represented by the above general formula (2-2a1), a compound in which R ²⁴ is a hydrogen atom in each of the above general formulas is combined with a fluorocarboxylic acid in the presence of an acid. It can be obtained by a conventionally known method such as a method of esterification by condensation or a method of esterification by condensation with a fluorocarboxylic acid halide in the presence of a base.

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

  Specifically, the structure represented by the following general formula (2-2b) in the general formula (2-2) includes the structures represented by the following formulas (8-1) to (8-5). Can be mentioned. Among these, the structure represented by the following formula (8-5) is preferable.

  The content ratio of the repeating unit (2-2) is preferably 80 mol% or less, more preferably 20 to 80 mol%, when the total repeating unit of the (C) polymer is 100 mol%. Preferably, it is 30 to 70 mol%. 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 immersion exposure liquid in the formed photoresist film can be reduced.

[1-3-3] Repeating unit represented by formula (2-3):
Examples of the divalent linking group represented by R ⁷ in the general formula (2-3) include a divalent hydrocarbon group having 1 to 30 carbon atoms. Moreover, the structure etc. which combined these hydrocarbon groups, a sulfur atom, an imino group, a carbonyl group, -CO-O-, or -CO-NH- can be mentioned.

Examples of R ^{7 having a} chain structure include carbon numbers such as methane, ethane, propane, butane, 2-methylpropane, pentane, 2-methylbutane, 2,2-dimethylpropane, hexane, heptane, octane, nonane, and decane. Examples thereof include a divalent hydrocarbon group having a structure obtained by removing two hydrogen atoms from 1 to 10 chain hydrocarbons.

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

The fluorinated alkyl group having 1 to 10 carbon atoms represented by R ¹⁰ in the general formula (2-3) is a linear or branched chain having 1 to 6 carbon atoms substituted with at least one fluorine atom. An alkyl group, a monovalent alicyclic hydrocarbon group having 4 to 10 carbon atoms substituted with at least one fluorine atom, or a group derived therefrom.

Specific examples of R ⁸ in the general formula (2-3) include groups represented by the following general formulas (2-3a1) to (2-3a3). Incidentally, in the general formula (2-3a1) and ^{(2-3a2), 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, a plurality of ^{R 25} is When present, each R ²⁵ may be the same or different. m ₁ represents an integer of 0 to 5, and m ₂ represents an integer of 0 to 4. In general 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 are bonded to each other to form an alicyclic ring having 4 to 20 carbon atoms. A formula structure may be formed.

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

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

As a C1-C10 alkyl group shown by R < ²⁶ > or R < ²⁷ > in General formula (2-3a3), a methyl group, an ethyl group, n-propyl group etc. can be mentioned, for example.

Examples of the alicyclic structure formed together with the carbon atoms to which R ²⁶ and R ²⁷ in General Formula (2-3a3) are bonded to each other include a cyclopentyl group, a cyclopentylmethyl group, and 1- (1 -Cyclopentylethyl) group, 1- (2-cyclopentylethyl) group, cyclohexyl group, cyclohexylmethyl group, 1- (1-cyclohexylethyl) group, 1- (2-cyclohexylethyl group), cycloheptyl group, cycloheptylmethyl Group, 1- (1-cycloheptylethyl) group, 1- (2-cycloheptylethyl) group, 2-norbornyl group and the like.

  Specific examples of the group represented by the general 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, and a 1-pentyl group. 2-pentyl group, 3-pentyl group, 1- (2-methylbutyl) group, 1- (3-methylbutyl) group, 2- (3-methylbutyl) group, neopentyl group, 1-hexyl group, 2-hexyl group , 3-hexyl group, 1- (2-methylpentyl) group, 1- (3-methylpentyl) group, 1- (4-methylpentyl) group, 2- (3-methylpentyl) group, 2- (4 -Methylpentyl) group, 3- (2-methylpentyl) group and the like. Among these, 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 general formula (2-3-1).

（一般式（２−３−１）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^７は２価の連結基を示す。Ｒ^８は、水素原子、酸解離性基、またはアルカリ解離性基を示す。）

(In general 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, R ⁸ represents a hydrogen atom, Indicates an acid dissociable group or an alkali dissociable group.)

Examples of the compound for forming the repeating unit represented by the general formula (2-3-1) include compounds represented by the following general formulas (2-3-1a) to (2-3-1d). Can be mentioned. In general 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 in which R ⁸ in the general formulas (2-3-1a) to (2-3-1d) is an acid-dissociable group or an alkali-dissociable group is, for example, R ⁸ in the above general formulas is a hydrogen atom. A compound or a derivative thereof can be synthesized as a raw material. For example, when R ⁸ is a group represented by the above general formulas (2-3a1) to (2-3a3), these compounds include, for example, a compound represented by the following general formula (9-1) and It can be obtained by reacting with any of the compounds represented by formulas (9-2) to (9-4).

（一般式（９−１）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^７は２価の連結基を示す。Ｒ^１０は、それぞれ独立に、水素原子、フッ素原子、または炭素数１〜１０のフッ素化アルキル基を示す。但し、全てのＲ^１０が水素原子である場合はない。Ｒ^２８は、水酸基またはハロゲン原子を示す。）

(In General Formula (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. R ¹⁰ independently represents hydrogen. An atom, a fluorine atom, or a fluorinated alkyl group having 1 to 10 carbon atoms, provided that not all R ¹⁰ are hydrogen atoms, and R ²⁸ represents a hydroxyl group or a halogen atom.

（一般式（９−２）中、Ｒ^２５は、ハロゲン原子、炭素数１〜１０のアルキル基、アルコキシル基、アシル基、またはアシロキシ基を示し、複数のＲ^２５が存在する場合、各Ｒ^２５は同一でも異なっていてもよい。Ｒ^２９はハロゲン原子を示す。ｍ１は０〜５の整数を示す。）

(In General 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. When a plurality of R ²⁵ are present, each R ²⁵ May be the same or different, R ²⁹ represents a halogen atom, and m1 represents an integer of 0 to 5.)

（一般式（９−３）中、Ｒ^２５は、ハロゲン原子、炭素数１〜１０のアルキル基、アルコキシル基、アシル基、またはアシロキシ基を示し、複数のＲ^２５が存在する場合、各Ｒ^２５は同一でも異なっていてもよい。Ｒ^３０はハロゲン原子を示す。ｍ２は０〜４の整数を示す。）

(In General Formula (9-3), 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. When a plurality of R ²⁵ are present, each R ²⁵ May be the same or different, R ³⁰ represents a halogen atom, and m2 represents an integer of 0 to 4.)

（一般式（９−４）中、Ｒ^２６及びＲ^２７は、それぞれ独立に、炭素数１〜１０のアルキル基を示す。）

(In General Formula (9-4), R ²⁶ and R ²⁷ each independently represents an alkyl group having 1 to 10 carbon atoms.)

As the halogen atom represented by R ²⁹ in formula (9-2), a chlorine atom is preferable.

As the halogen atom represented by R ³⁰ in formula (9-3), a boron atom is preferable.

As a C1-C10 alkyl group shown by R < ²⁶ > or R < ²⁷ > in General formula (9-4), a methyl group, an ethyl group, n-propyl group etc. can be mentioned, for example.

In addition, when R ⁸ in the general formula (2-3) is a group represented by the above general formulas (2-3a1) to (2-3a3), the compound having such a group includes, for example, the following general formula It can also be obtained by reacting a compound represented by the formula (10-1) with a compound represented by the following general formula (10-2).

（一般式（１０−１）中、Ｒ^７は２価の連結基を示す。Ｒ^８は、一般式（２−３ａ１）〜（２−３ａ３）で表される基を示し、Ｒ^１０は、それぞれ独立に、水素原子、フッ素原子、または炭素数１〜１０のフッ素化アルキル基を示す。但し、全てのＲ^１０が水素原子である場合はない。）

(In General Formula (10-1), R ⁷ represents a divalent linking group. R ⁸ represents a group represented by General Formulas (2-3a1) to (2-3a3), and R ¹⁰ represents: Each independently represents a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 10 carbon atoms, provided that not all R ¹⁰ are hydrogen atoms.

（一般式（１０−２）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^４７は、水酸基またはハロゲン原子を示す。）

(In General Formula (10-2), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. R ⁴⁷ represents a hydroxyl group or a halogen atom.)

  The content ratio of the repeating unit (2-3) is preferably 50 mol% or less, more preferably 5 to 30 mol%, when the total repeating unit of the (C) polymer is 100 mol%. Preferably, it is 5-20 mol%, and it is especially preferable. When the content ratio is within the above range, there is an advantage that the balance between water repellency and affinity for the developer in the formed photoresist film becomes good.

  In addition, as described above, the polymer (C) is at least one selected from the group consisting of the repeating unit (2-1), the repeating unit (2-2), and the repeating unit (2-3). Since it preferably has a repeating unit, it may have any one of repeating units (2-1) to (2-3), or may have two or more, It is preferable to have 2 or more types, and it is more preferable to have a repeating unit (2-2) and a repeating unit (2-3).

When the polymer (C) has an alkali dissociable group in at least one of the repeating unit (2-2) and the repeating unit (2-3), the (C) polymer has an affinity for the developer. Can be improved. This is considered to be because (C) the polymer reacts with the developer to generate a polar group in the development step of the resist pattern forming method described later. Further, when R ⁸ in the general formulas (2-2) and (2-3) is a hydrogen atom, the repeating units (2-2) and (2-3) are a hydroxyl group or a carboxyl group which is a polar group. Will have. And when (C) polymer contains such a repeating unit, the affinity with respect to a developing solution of (C) polymer can be improved in the image development process of the resist pattern formation method mentioned later.

[1-3-4] Repeating unit (i):
(C) The polymer is a repeating unit containing at least one of the group represented by the following general formula (2-4) and the group represented by the following general formula (2-5) (however, the above general formula It is preferable to further include a repeating unit represented by formula (2-3) (hereinafter may be referred to as “repeating unit (i)”). By further including such a repeating unit (i), the solubility of the formed photoresist film in the developer is improved.

（一般式（２−４）中、Ｒ^１１は、フッ素原子で置換された炭素数１〜１０の炭化水素基を示す。）

(In the general formula (2-4), R ¹¹ represents a C 1-10 hydrocarbon group substituted with a fluorine atom.)

In the general formula (2-4), the hydrocarbon group having 1 to 10 carbon atoms substituted by the fluorine atom represented by R ¹¹ is such that one or more hydrogen atoms in the hydrocarbon group having 1 to 10 carbon atoms are fluorine. Although it will not specifically limit if it is substituted by the atom, For example, a trifluoromethyl group etc. are preferable.

  The main chain skeleton of the repeating unit (i) is not particularly limited, but is preferably a methacrylic acid ester, an acrylic acid ester, an α-trifluoroacrylic acid ester, or the like.

  Examples of the repeating unit (i) include a repeating unit derived from a compound represented by the following general formula (11-1), a repeating unit derived from a compound represented by the following general formula (11-2), and the like. be able to.

（一般式（１１−１）及び（１１−２）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^３２は、単結合、または炭素数１〜２０の２価の直鎖状、分岐状若しくは環状の、飽和若しくは不飽和の炭化水素基を示す。一般式（１１−１）中、Ｒ^３１は、フッ素原子で置換された炭素数１〜１０の炭化水素基を示す。ｔは０または１を示す。）

(In General Formulas (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 C 1-20 carbon atom. A divalent linear, branched or cyclic, saturated or unsaturated hydrocarbon group, wherein R ³¹ is a carbon atom having 1 to 10 carbon atoms substituted with a fluorine atom; Represents a hydrogen group, t represents 0 or 1)

As the divalent linear, branched or cyclic, saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, represented by R ³² in the general formulas (11-1) and (11-2), Examples thereof include the same divalent organic groups represented by R ²⁰ in the general formula (6). As the general formula (11-1) hydrocarbon group having 1 to 10 carbon atoms which is substituted with a fluorine atom represented by ^{R 31} in one or more of hydrogen in a hydrocarbon group having 1 to 10 carbon atoms Although it will not specifically limit if an atom is substituted by the fluorine atom, For example, a trifluoromethyl group etc. are preferable.

  In addition, you may use repeating unit (i) individually by 1 type or 2 or more types.

  The content ratio of the repeating unit (i) is preferably 50 mol% or less, more preferably 5 to 30 mol%, when the total repeating unit of the polymer (C) is 100 mol%, It is particularly preferably 5 to 20 mol%. When the content ratio is within the above range, there is an advantage that the balance between water repellency and affinity for the developer in the formed photoresist film becomes good.

[1-3-5] Other repeating unit (b):
(C) The polymer may contain other repeating units (b) in addition to the repeating units (2-1) to (2-3) and the repeating unit (i).

  Examples of the other repeating unit (b) include each repeating unit represented by the general formulas (2-1) to (2-5).

  Furthermore, the repeating unit represented by the following general formula (12) is preferable among the repeating units represented by the general formula (2-1). By including the repeating unit represented by the following general formula (12), the difference between the advancing contact angle and the receding contact angle of the photoresist film can be reduced, so that the scanning speed during immersion exposure is improved. Can do.

（一般式（１２）中、Ｒ^１は、水素原子、低級アルキル基、またはハロゲン化低級アルキル基を示す。Ｒ^３３は、炭素数１〜４の直鎖状または分岐状のアルキル基を示す。ｋは、１〜４の整数を示す。）

(In General Formula (12), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. R ³³ represents a linear or branched alkyl group having 1 to 4 carbon atoms. 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 general formula (12) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n- There are a butyl group, a 2-methylpropyl group, a 1-methylpropyl group, a t-butyl group, and the like.

  (C) A polymer contains a fluorine atom, and even if it is a case where (A) polymer contains a fluorine atom, the content rate of a fluorine atom is larger than (A) polymer. The content ratio of the fluorine atom is usually 5% by mass or more, preferably 5 to 50% by mass, and preferably 5 to 40% by mass when the total amount of the polymer (C) is 100% by mass. Is more preferable. (C) By making the content ratio of fluorine atoms in the polymer within the above range, the water repellency of the formed photoresist film can be increased, and it is not necessary to separately form a liquid immersion upper layer film during liquid immersion exposure. There is an advantage that a photoresist film having good water repellency can be formed. Moreover, when the said content rate becomes smaller than (A) polymer, there exists a possibility that the grade of oil repellency of (A) polymer and (C) polymer may be reversed, and the grade of oil repellency is In the case of reverse rotation, the (C) polymer is less likely to be unevenly distributed on the surface of the photoresist film, so that the effect of the present invention cannot be obtained.

  (C) The content of the polymer is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the (A) polymer, It is particularly preferably 1 to 5 parts by mass. When the content is within the above range, the (C) polymer is unevenly distributed in the surface layer of the photoresist film, so that there is an effect that good water repellency is obtained.

  (C) The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is preferably 1,000 to 50,000, and preferably 1,000 to 40,000. More preferred is 1,000 to 30,000. If the Mw is less than 1,000, a photoresist film having a sufficient receding contact angle cannot be obtained, and defects due to the use of the immersion exposure liquid may occur. On the other hand, if it exceeds 50,000, the developability of the photoresist film may be lowered. The ratio (Mw / Mn) of (C) the polymer Mw to the polystyrene-equivalent number average molecular weight (Mn) by the GPC method is preferably 1 to 5, and more preferably 1 to 4. .

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

  (C) The polymer is, for example, a monomer (polymerizable unsaturated monomer) for forming each repeating unit described above, hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds. It can manufacture by superposing | polymerizing in a suitable solvent in presence of a chain transfer agent as needed using radical polymerization initiators.

  Examples of the solvent used for the polymerization include the same solvents as those used for the polymerization of the polymer (A). Moreover, the reaction temperature in superposition | polymerization is 40-150 degreeC normally, and it is preferable that it is 50-120 degreeC. The reaction time is usually 1 to 48 hours, preferably 1 to 24 hours.

[1-4] Other components:
The radiation-sensitive resin composition of the present invention may further contain other components in addition to (A) the polymer, (B) the radiation-sensitive acid generator, and (C) the polymer. Other components include, for example, acid diffusion control agents, solvents, lactone compounds, and other additives (for example, alicyclic additives, surfactants, sensitizers, antihalation agents, adhesion assistants, storage stabilizers) Agents, antifoaming agents, etc.).

[1-4-1] Acid diffusion controller:
Examples of the acid diffusion controller include a compound represented by the following general formula (13) (hereinafter sometimes referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule ( Hereinafter, sometimes referred to as “nitrogen-containing compound (II)”, compounds having 3 or more nitrogen atoms (hereinafter sometimes referred to as “nitrogen-containing compound (III)”), amide group-containing compounds, urea compounds And nitrogen-containing heterocyclic compounds. When such an acid diffusion controller is further included, the pattern shape and dimensional fidelity can be improved.

（一般式（１３）中、Ｒ^３４〜Ｒ^３６は、相互に独立に、水素原子、置換されていてもよい、直鎖状、分岐状若しくは環状のアルキル基、アリール基、アラルキル基、または酸解離性基を示す。）

(In the general formula (13), R ^{34 to} R ³⁶ are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, an aryl group, an aralkyl group, or an acid. Indicates a dissociable group.)

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

（一般式（１３−１）中、Ｒ^３７〜Ｒ^３９は、相互に独立に、炭素数１〜４の直鎖状若しくは分岐状のアルキル基、または炭素数４〜２０の１価の脂環式炭化水素基若しくはそれから誘導される基を示すか、或いはＲ^３８及びＲ^３９が相互に結合してそれぞれが結合している炭素原子とともに炭素数４〜２０の２価の脂環式炭化水素基若しくはそれから誘導される基を示し、Ｒ^３７が、炭素数１〜４の直鎖状若しくは分岐状のアルキル基、または炭素数４〜２０の１価の脂環式炭化水素基若しくはそれから誘導される基を示す。）

(In General Formula (13-1), R ^{37 to} R ³⁹ are each independently a linear or branched alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic ring having 4 to 20 carbon atoms. A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atom to which R ³⁸ and R ³⁹ are bonded to each other, or represents a group represented by the formula hydrocarbon group or a group derived therefrom Or a group derived therefrom, wherein R ³⁷ is a linear or branched alkyl group having 1 to 4 carbon atoms, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or derived therefrom. Group.)

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ^{37 to} R ³⁹ in the general formula (13-1) include a methyl group, an ethyl group, an n-propyl group, i- A propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like can be mentioned.

Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^{37 to} R ³⁹ in the general formula (13-1) include norbornane, tricyclodecane, tetracyclododecane, adamantane, Examples thereof include groups consisting of alicyclic rings derived from cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane. And as a group induced | guided | derived from the said alicyclic hydrocarbon group, the above-mentioned monovalent alicyclic hydrocarbon group is a methyl group, an ethyl group, n-propyl group, i-propyl group, n-, for example. A group substituted with one or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as butyl group, 2-methylpropyl group, 1-methylpropyl group and t-butyl group. And so on.

Among these, the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^{37 to} R ³⁹ is an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane, or cyclohexane. An alicyclic hydrocarbon group composed of an aromatic ring and a group in which this alicyclic hydrocarbon group is substituted with an alkyl group are preferred.

A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a group derived therefrom, together with the carbon atoms to which R ³⁸ and R ^{39 in} general formula (13-1) are bonded to each other As the above-mentioned divalent alicyclic hydrocarbon group, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group And a group substituted with one or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as t-butyl group.

  Specific examples of the nitrogen-containing compound (I) having no acid dissociable group include trialkylamines such as tri-n-hexylamine, tri-n-heptylamine, and tri-n-octylamine. There can be mentioned.

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

  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 polymers of polyethyleneimine, polyallylamine, dimethylaminoethylacrylamide, and the like.

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

In addition, as the acid diffusion controller, a compound represented by the following general formula (14) can also be used.
X ⁺ Z ^- ··· (14)
(In the general formula (14), ^{X +} is a cation represented by the following general formula (14-1) or (14-2) .Z ^- is OH ^-, the formula (14-3 ) ^R 41 -COO ^- an anion represented by the general formula ^(14-4) R 40 -SO ₃ ^- anionic represented by or the _{^{formula, (14-5) R 40 -N -}} -SO 2 -R 41 Provided that in the general formulas (14-3) to (14-5), R ⁴⁰ represents an optionally substituted alkyl group, alicyclic hydrocarbon group, or aryl group. R ⁴¹ is an optionally substituted fluorinated alkyl group, alicyclic fluorinated hydrocarbon group or fluorinated aryl group.

In the general formula (14-1), R ^{42 to} R ⁴⁴ are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom, and in the general formula (14-2), R ^{42 45} and R ⁴⁶ are each independently a hydrogen atom, 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 that is decomposed by exposure and loses acid diffusion controllability (hereinafter also referred to as “photodegradable acid diffusion control agent”). By containing the compound represented by the formula (14), the acid diffuses in the exposed area, and the acid diffusion is controlled in the unexposed area, so that the contrast between the exposed area and the unexposed area is excellent (that is, In particular, the boundary portion between the exposed portion and the unexposed portion becomes clear), and in particular, LWR and MEEF (Mask Error Enhancement Factor (amplification factor of line width shift due to mask width shift)) of the radiation-sensitive resin composition of the present invention. ) Is effective for improvement.

X ⁺ in the general formula (14) is a cation represented by the general formula (14-1) or (14-2) as described above. R ^{42 to} R ⁴⁴ in the general formula (14-1) are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom, and among these, in the above formula (14) In view of the effect of reducing the solubility of the represented compound in a developer, a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom is preferable. R ⁴⁵ and R ⁴⁶ in the general formula (14-2) are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom. Among these, a hydrogen atom, an alkyl group, A halogen atom is preferred.

Z ⁻ in the general formula (14) is OH ⁻ , an anion represented by the general formula (14-3) R ⁴⁰ —COO ^— , an anion represented by the general formula (14-4) R ⁴⁰ —SO ₃ ^—. Or an anion represented by general formula (14-5) R ⁴⁰ —N ⁻ —SO ₂ —R ⁴¹ (wherein, in general formulas (14-3) to (14-5), R ⁴⁰ represents An optionally substituted alkyl group, an alicyclic hydrocarbon group, or an aryl group, and R ⁴¹ is an optionally substituted fluorinated alkyl group, an alicyclic fluorinated hydrocarbon group, or a fluorinated aryl group; is there).

Z ⁻ in the general formula (14) is an anion represented by the following formula (15-1) (that is, an anion represented by the general formula (14-3) in which R ⁴⁰ is a phenyl group), An anion represented by the following formula (15-1) (that is, R ⁴⁰ is a group derived from 1,7,7-trimethylbicyclo [2.2.1] heptan-2-one, ), Or an anion represented by the following formula (15-3) (that is, R ⁴⁰ is a butyl group and R ⁴¹ is a trifluoromethyl group, represented by the general formula (14-5)). An anion).

  The photodegradable acid diffusion controller is represented by the general formula (14), and specifically, is a sulfonium salt compound or an iodonium salt compound that satisfies the above conditions.

  Examples of the sulfonium salt compound include triphenylsulfonium hydroxide, triphenylsulfonium acetate, triphenylsulfonium salicylate, diphenyl-4-hydroxyphenylsulfonium hydroxide, diphenyl-4-hydroxyphenylsulfonium acetate, diphenyl-4- Examples thereof include hydroxyphenylsulfonium salicylate, triphenylsulfonium 10-camphor sulfonate, 4-t-butoxyphenyl diphenylsulfonium 10-camphor sulfonate, and the like. In addition, these sulfonium salt compounds can be used individually by 1 type or in combination of 2 or more types.

  Examples of the iodonium salt compound include bis (4-t-butylphenyl) iodonium hydroxide, bis (4-t-butylphenyl) iodonium acetate, bis (4-t-butylphenyl) iodonium hydroxide, bis (4-t-butylphenyl) iodonium acetate, bis (4-t-butylphenyl) iodonium salicylate, 4-t-butylphenyl-4-hydroxyphenyliodonium hydroxide, 4-t-butylphenyl-4-hydroxy Phenyliodonium acetate, 4-t-butylphenyl-4-hydroxyphenyliodonium salicylate, bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, diphenyliodonium 10-camphor Or the like can be mentioned sulfonates. In addition, these iodonium salt compounds can be used individually by 1 type or in combination of 2 or more types. The said photodegradable acid diffusion control agent can be used individually by 1 type or in combination of 2 or more types.

  Among these acid diffusion control agents, nitrogen-containing compounds (I), nitrogen-containing compounds (II), nitrogen-containing heterocyclic compounds, and photodegradable acid diffusion control agents are preferred. In addition, an acid diffusion control agent can be used individually by 1 type or in combination of 2 or more types.

  The content of the acid diffusion controller is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, with respect to 100 parts by mass of the polymer (A). If the content of the acid diffusion controller 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-hydroxypropionates; alkyl 3-alkoxypropionates. it can.

  These solvents can be used singly or in combination of two or more. Among these solvents, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, Alkyl 2-hydroxypropionates and alkyl 3-alkoxypropionates are preferred.

[1-4-3] Lactone compound:
The lactone compound effectively segregates the (C) polymer on the surface of the photoresist film. That is, by containing such a lactone compound, the surface of the photoresist film can be made to exhibit water repellency in immersion exposure. (C) The water repellency of the surface of the photoresist film can be reduced even if the amount of the polymer added is smaller than the conventional amount. Can be maintained. In addition to not impairing basic characteristics such as LWR, development defects, and pattern collapse resistance, components ((B) acid generator, etc.) in the photoresist film are eluted into the immersion exposure liquid. Even when high-speed immersion exposure is performed, it is difficult to leave droplets on the photoresist film, so it is possible to suppress defects derived from immersion exposure liquids such as watermark defects. A simple photoresist film can be formed.

  Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, and norbornane lactone. In addition, a lactone compound can be used individually by 1 type or in combination of 2 or more types.

  The amount of the lactone compound used is preferably 30 to 200 parts by mass, and more preferably 50 to 150 parts by mass with respect to 100 parts by mass of the (A) polymer. When the amount used is within the above range, the polymer (C) can be segregated on the surface of the photoresist film even when the amount of the polymer (C) used is small. If the amount used 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 significantly deteriorated.

  The radiation sensitive resin composition of the present invention, for example, after mixing (A) polymer, (B) radiation sensitive acid generator, (C) polymer, and other components (excluding solvent), As a composition solution, it is dissolved in a solvent so that the total solid content 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 μm, for example. Can be prepared.

[2] Resist pattern forming method:
The resist pattern forming method of the present invention includes a photoresist film forming step of forming a photoresist film by coating the radiation-sensitive resin composition of the present invention on a substrate, and immersion exposure on the formed photoresist film. An exposure step of irradiating the photoresist film with radiation through the immersion exposure liquid, and developing the photoresist film irradiated with radiation with a developer to form a resist pattern And a process. According to such a method, it is possible to form a resist pattern with good LWR and little film loss.

[2-1] Photoresist film forming step:
The photoresist film forming step is a step of 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 and a wafer coated with aluminum.

  As a method for forming a photoresist film on a substrate, for example, a composition solution obtained by dissolving the radiation-sensitive resin composition of the present invention in a solvent is conventionally known, such as spin coating, cast coating, roll coating, etc. The method of apply | coating on a board | substrate by this method can be mentioned.

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

  Note that after the photoresist film is formed, the photoresist film may be subjected to heat treatment (hereinafter may be referred to as “PB”).

[2-2] Exposure process:
The exposure step is a step of disposing an immersion exposure liquid on the formed photoresist film and irradiating the photoresist film with radiation through the immersion exposure liquid.

  Examples of the liquid for immersion exposure include pure water and a fluorine-based inert liquid.

  The light such as radiation used for exposure can be appropriately selected and used according to the type of the acid generator used. For example, visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams, etc. Among these, far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser (wavelength 193 nm) is particularly preferable.

  Further, the exposure conditions such as the exposure amount can be appropriately selected according to the composition of the photoresist composition and the kind of the additive. And after exposure, it is preferable to perform heat processing (the heat processing after exposure may be described as "PEB" below). This is because the dissociation reaction of the acid dissociable group in the polymer (A) proceeds smoothly by PEB. The heating condition of PEB varies depending on the composition of the photoresist composition, but is usually 30 to 200 ° C, preferably 50 to 170 ° C.

  In order to maximize the potential of the radiation sensitive resin composition, an organic or inorganic antireflection film can be formed on the substrate in advance before forming the photoresist film (for example, Japanese Patent Publication No. 6-12458 (Japanese Patent Laid-Open No. 59-93448). In order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film (see, for example, JP-A-5-188598) may be formed on the photoresist film. The radiation-sensitive resin composition of the present invention does not require the formation of a liquid immersion upper layer film, that is, can form a photoresist film that has a good LWR after development and is less likely to cause film loss. However, for example, a liquid immersion upper layer film as disclosed in JP-A-2005-352384 may be formed. These techniques can be used in combination.

[2-3] Development step:
The development step is a step of developing a photoresist film irradiated with radiation with a developer to form a resist pattern.

  Developers used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine , Methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4 .3.0] An alkaline aqueous solution in which at least one of alkaline compounds such as 5-nonene is dissolved is preferable. The concentration of the alkaline aqueous solution is usually 10% by mass or less. When the concentration of the alkaline aqueous solution exceeds 10% by mass, the unexposed area may be dissolved in the developer.

  An organic solvent can be further added to the developer composed of 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; methyl alcohol, ethyl alcohol, and n-propyl alcohol. , Alcohols such as i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol and 1,4-hexanedimethylol; ethers such as tetrahydrofuran and dioxane; Examples thereof include esters such as ethyl acetate, n-butyl acetate and i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonylacetone and dimethylformamide. These organic solvents can be used alone or in combination of two or more. The addition amount of the organic solvent is preferably 100% by volume or less with respect to the alkaline aqueous solution. If the addition amount of the organic solvent exceeds 100% by volume, the developability is lowered, and there is a possibility that the development residue in the exposed area increases. In addition, an appropriate amount of a surfactant or the like can be added to the developer composed of an alkaline aqueous solution. In addition, after developing with the developing solution which consists of alkaline aqueous solution, it usually wash | cleans with water and dries.

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

[Elution volume]:
A silicon film in which a resist film having a thickness of 150 nm is formed by spin-coating a radiation-sensitive resin composition (composition solution) on a silicon wafer by CLEAN TRACK ACT8 (manufactured by Tokyo Electron) and baking at 100 ° C. for 60 seconds. A wafer was created. A Teflon ring having a diameter of 1 cm and a thickness of 1 mm was placed on the silicon wafer and filled with 1 mL of ultrapure water so that the ultrapure water and the resist film were in contact with each other. After contacting the ultrapure water and the resist film for 3 seconds, 5 seconds, 10 seconds, 30 seconds, 60 seconds, 120 seconds, and 300 seconds, respectively, the filled ultrapure water was recovered with a glass syringe. Was used as a sample for analysis. Note that the recovery rate of ultrapure water after the experiment was 95% or more.

  Subsequently, the peak intensity of the anion part of the photoacid generator in the obtained ultrapure water was measured using a single “CAPCELL PAK MG” manufactured by Shiseido Co., Ltd., a flow rate of 0.2 ml / min, and a measurement temperature of 35 ° C. Then, LC-MS (liquid chromatograph mass spectrometer, LC part: SERIES1100 manufactured by AGILENT) under measurement conditions using water / methanol (3/7) added with 0.1% by mass of formic acid as an effluent solvent. MS part: Perseptive Biosystems, Inc., Mariner).

At this time, the respective peak intensities of the 1 ppb, 10 ppb, and 100 ppb aqueous solutions of the photoacid generator were measured under the above measurement conditions to create a calibration curve, and the elution amount was calculated from the peak intensity using this calibration curve. The evaluation criteria are “bad” when the elution amount is 2.0 × 10 ⁻¹² mol / cm ² / sec or more, and when the elution amount is less than 2.0 × 10 ⁻¹² mol / cm ² / sec. Was “good”.

[sensitivity]:
A 12-inch silicon wafer on which a 105 nm lower antireflection film (“ARC66”, manufactured by Nissan Chemical Industries, Ltd.) was formed was prepared, and the composition solution was applied onto the thin film of the substrate by spin coating on the surface of the silicon wafer. Above, soft baking (SB) (shown as “SB” in Table 5) was performed for 60 seconds at a temperature (100 ° C.) shown in Table 5 to form a resist film having a thickness of 90 nm. The formed resist film having a thickness of 90 nm was exposed through a mask pattern using a full-field reduced projection immersion exposure apparatus “S610C” (numerical aperture 1.30) manufactured by Nikon Corporation. Thereafter, PEB (PEB) was performed at the temperature shown in Table 5 for 60 seconds, and then developed with a 2.38 mass% TMAH aqueous solution at 25 ° C. for 30 seconds, washed with water, and dried to form a positive resist pattern. did. At this time, the exposure amount (mJ / cm ² ) formed in a one-to-one line and space having a line width of 45 nm and a line width formed through a one-to-one line and space mask having a dimension of 45 nm is defined as an optimum exposure amount. The optimum exposure amount (mJ / cm ² ) was defined as “sensitivity”.

[LWR (Line Width Roughness)]:
A 45 nm (1L / 1S) pattern is formed on the resist film at the optimum exposure dose for the evaluation of the above [sensitivity], and the formed 45 nm (1L / 1S) pattern is measured with a length measurement SEM (manufactured by Hitachi High-Technologies Corporation, model number). Using “CG4000”), the line width was measured at an arbitrary point from the top of the pattern. The measurement variation for the line width is expressed by 3 sigma, and the LWR was evaluated based on this value.

[Top loss]:
In observing the 45 nm 1L / 1S pattern resolved at the optimum exposure dose, the pattern cross section was observed with a scanning electron microscope (SEM) “S-4800” manufactured by Hitachi High-Technologies Corporation, and its height (pattern height). Was measured. Then, the amount of top loss was calculated by subtracting the pattern height value from the initial film thickness (90 nm). The top loss was evaluated based on the amount of top loss.

  In addition, each polymer (A-1)-(A-8) ((A) polymer using the compound represented by the following formula (M-1)-(M-15) in the following synthesis examples 1-12. ) Was prepared.

(Synthesis Example 1)
(Preparation of polymer (A-1))
24.61 g (30 mol%) of the compound (M-1) represented by the formula (M-1), 54.19 g (50 mol%) of the compound (M-8) represented by the formula (M-8), Further, 9.08 g (10 mol%) of the compound (M-9) represented by the following formula (M-9) is dissolved in 200 g of 2-butanone, and further dimethyl 2,2′-azobisisobutyronitrile. 4.00 g was added to prepare a monomer solution.

  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, and then stirred while the reaction kettle was stirred. The monomer solution prepared in advance was heated and dropped at 3 ° C. using a dropping funnel over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled to 30 ° C. or less by water cooling. Thereafter, the mixture was added to 2000 g of methanol to precipitate a white powder, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 400 g of methanol as a slurry. Then, it was filtered and dried at 50 ° C. for 17 hours to obtain a white powder copolymer (yield 79 g, yield 79%).

This copolymer has Mw of 5500, Mw / Mn = 1.41, and as a result of ¹³ C-NMR analysis, as shown in Table 3, the compound represented by formula (M-1) (M -1), compound (M-5) represented by formula (M-5), compound (M-8) represented by formula (M-8), compound represented by formula (M-9) ( The content (mol%) of each repeating unit derived from M-9) was 30.2: 9.9: 10.2: 49.7, respectively. This copolymer is referred to as “polymer (A-1)”. In addition, Table 3 shows the physical property values of the polymer (A-1).

(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 compounds (monomer types) and the blending ratios shown in Table 1 were used. In addition, Table 3 shows physical property values of the polymers (A-2) to (A-8).

(Synthesis Example 9)
(Preparation of polymer (C-1))
50.88 g (60 mol%) of the compound (M-3) represented by the formula (M-3), 30.06 g (15 mol%) of the compound (M-13) represented by the formula (m-13), Further, 19.06 g (25 mol%) of the compound (M-14) represented by the formula (M-14) is dissolved in 100 g of 2-butanone, and further dimethyl 2,2′-azobisisobutyronitrile. 3.55 g was added to prepare a monomer solution. On the other hand, 100 g of 2-butanone was charged into a 1000 mL three-necked flask and purged with nitrogen for 30 minutes, and then the reaction kettle was heated to 80 ° C. with stirring.

  Subsequently, the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled to 30 ° C. or less by water cooling, and the polymerization solution was transferred to a 2 L separatory funnel. Thereafter, the polymerization solution was diluted with 300 g of n-hexane, and 1200 g of methanol was added and mixed, and then allowed to stand for 30 minutes. The lower layer was recovered to obtain a propylene glycol monomethyl ether acetate solution.

The solid content (polymer) of this propylene glycol monomethyl ether acetate solution was 65%, Mw was 6400, Mw / Mn was 1.41, and as a result of ¹³ C-NMR analysis, the fluorine content was Is 9.14 mass%, a compound represented by formula (M-3), a compound (M-13) represented by (M-3), a compound represented by formula (M-13) (M-13) ) And the content (mol%) of each repeating unit derived from the compound represented by formula (M-14) compound (M-14) was 60.3: 24.9: 14.8, respectively. . This copolymer is referred to as “polymer (C-1)”.

(Synthesis Examples 10-12)
Polymers (C-2) to (C-4) were prepared in the same manner as in Synthesis Example 9 except that the compounds (monomer types) and the blending ratios shown in Table 2 were used. In addition, Table 3 shows physical property values of the polymers (C-2) to (C-4).

  Next, the “acid generator” and “acid diffusion controller” used in Examples and Comparative Examples are shown below.

The “solvent” and “additive” used in Examples and Comparative Examples are shown below.
Solvent (E-1): Propylene glycol monomethyl ether acetate
Solvent (E-2): cyclohexanone,
Additive (F-1): γ-butyrolactone.

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

The radiation sensitive resin composition of this example has an elution evaluation of “good”, a sensitivity evaluation value of 20.0 mJ / cm ² , an LWR evaluation value of 3.5 nm, The value in the top loss evaluation was 15 nm.

(Examples 2 to 15, Reference Examples 16 to 18 , Comparative Examples 1 to 4)
Except having set it as the compound shown in Table 4, and the compounding quantity, it carried out similarly to Example 1, and prepared the composition solution which consists of each radiation sensitive resin composition. The various evaluations described above were performed using the prepared composition solutions. The evaluation results are shown in Table 5.

As is clear from Table 5, the radiation sensitive resin compositions of Examples 1 to 15 have better LWR after development and film loss compared to the radiation sensitive resin compositions of Comparative Examples 1 to 4. It was confirmed that it was difficult.

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

Claims (7)

(A) a repeating unit represented by the following general formula (1) and a polymer having an acid dissociable group (however, excluding a polymer having a crosslinking group) ;
(B) a radiation sensitive acid generator;
(C) a polymer containing a fluorine atom (excluding a polymer having a crosslinking group) ;
Only including,
The acid dissociable group of the polymer (A) is a group represented by the general formula “—C (R) ₃ ”,
In the group represented by the general formula “—C (R) ₃ ”, any two Rs are bonded to each other, and the divalent alicyclic ring having 4 to 20 carbon atoms together with the carbon atom to which each group is bonded A hydrocarbon group or a group derived therefrom, and the remaining one R is a linear or branched alkyl group having 1 to 4 carbon atoms, monovalent alicyclic carbonization having 4 to 20 carbon atoms A hydrogen group or a group derived therefrom;
The radiation-sensitive resin composition in which any two Rs are bonded to each other, and the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms is an adamantylene group together with the carbon atoms to which they are bonded . .

(In General Formula (1), 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, or alkanediyl. Represents an oxy group or an alkanediylcarbonyloxy group, and R ³ represents a trivalent organic group.) The radiation-sensitive resin composition according to claim 1, wherein the repeating unit represented by the general formula (1) is a repeating unit represented by the following general formula (1-1).

(In General Formula (1-1), 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 ⁵⁰ represents a group represented by the following general formula (a) or a group represented by the following general formula (b).

(In General Formula (a), n1 represents an integer of 0 to 2. In General Formula (b), n2 to n5 each independently represents an integer of 0 to 2. General Formula (a) and General Formula In (b), * represents a bond bonded to R ² in the general formula (1-1), provided that the group represented by the general formula (a) and the group represented by the general formula (b). In which at least one of the carbon atoms constituting these groups may be substituted with an oxygen atom, a nitrogen atom or a carbonyl group, and the group represented by the general formula (a) and the general formula (b) The group represented may have a substituent.) The radiation sensitive resin composition according to claim 1 or 2, wherein the repeating unit represented by the general formula (1) is a repeating unit represented by the following general formula (1-1a).

(In General Formula (1-1a), 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 ⁵¹ represents a group represented by the following general formula (a1) or a group represented by the following general formula (b1).

(In general formula (a1) and general formula (b1), * represents a bond that binds to R ² in general formula (1-1a).) The said (C) polymer has at least 1 sort (s) of repeating unit selected from the group which consists of each repeating unit represented by the following general formula (2-1)-(2-3). The radiation sensitive resin composition as described in any one of Claims.

(In General Formulas (2-1) to (2-3), R ¹ represents a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group. In General Formula (2-1), R ⁹ represents the number of carbon atoms. 1 to 30 represents a fluorinated alkyl group, R ⁶ in the general formula (2-2) represents a single bond or a (g + 1) -valent linking group, and g represents an integer of 1 to 3. 2-3), R ⁷ represents a divalent linking group, and R ⁸ represents a hydrogen atom, an acid-dissociable group, or an alkali-dissociable group in general formulas (2-2) and (2-3). And each R ¹⁰ independently represents a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 10 carbon atoms, provided that not all R ¹⁰ are hydrogen atoms.) The polymer (C) is a repeating unit containing at least one of the group represented by the following general formula (2-4) and the group represented by the following general formula (2-5) (however, the general The radiation-sensitive resin composition according to claim 4, further comprising a repeating unit represented by formula (2-3).

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