JP2010176036A - Radiation-sensitive resin composition and resist pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition which is a material of a resist film capable of obtaining good pattern configuration, less liable to elute into an immersion liquid for liquid immersion lithography, such as water, having a large receding contact angle to the immersion liquid, and less liable to cause development defects. <P>SOLUTION: The radiation-sensitive resin composition contains: a first polymer (A) having predetermined repeating units; a second polymer (B) which has an acid-dissociable functional group dissociating under the action of an acid and becomes alkali-soluble upon the dissociation of the acid-dissociable functional group; and a radiation-sensitive acid generator (C). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radiation-sensitive resin composition and a resist pattern forming method. More specifically, it is a resist film material that can obtain a good pattern shape, is difficult to elute in an immersion exposure liquid such as water, has a large receding contact angle with the immersion exposure liquid, and does not easily cause development defects. The present invention relates to a radiation sensitive resin composition and a resist pattern forming method.

  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 is desired. However, in the conventional lithography technique, near ultraviolet rays such as i-line are used as radiation, and with this near ultraviolet rays, it is extremely difficult to perform microfabrication at a level of 0.10 μm or less (sub quarter micron level). 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 spectrum of a mercury lamp, far ultraviolet rays such as an excimer laser, X-rays, and electron beams. Among these, a KrF excimer laser (wavelength 248 nm) and an ArF excimer laser ( A wavelength of 193 nm) is attracting attention.

  Along with the attention of excimer lasers, many resist film materials for excimer lasers have been proposed. For example, it contains a component having an acid-dissociable functional group and a component that generates an acid upon irradiation with radiation (hereinafter referred to as “exposure”) (hereinafter referred to as “acid generator”). Examples thereof include a composition using an amplification effect (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. In this composition, t-butyl ester group or t-butyl carbonate group present in the resin is dissociated by the action of an acid generated by exposure, and the resin is an acidic group comprising a carboxyl group or a phenolic hydroxyl group. Will have. As a result, the exposed region of the resist film becomes readily soluble in an alkali developer, so that a desired resist pattern can be formed.

  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 can be shortened, or the numerical aperture (NA) of the lens can be increased. However, shortening the light source wavelength requires a new exposure apparatus, but such an apparatus is expensive. Further, when the numerical aperture of the lens is increased, there is a problem that the depth of focus decreases even if the resolution can be improved because the resolution and the depth of focus are in a trade-off relationship.

  Therefore, recently, a liquid immersion lithography (liquid immersion lithography) method has been reported as a lithography technique for solving such problems. In this method, an immersion exposure liquid (for example, pure water or a fluorine-based inert liquid) is interposed between the lens and the resist film (on the resist film) during exposure. According to this method, the exposure optical path space, which has been conventionally filled with an inert gas such as air or nitrogen, is filled with the immersion exposure liquid having a refractive index (n) larger than that of air or the like. Even when this exposure light is used, the same effect as that obtained when the exposure light is shortened can be obtained. That is, high resolution is obtained and there is no reduction in the depth of focus.

  Therefore, according to such immersion exposure, it is possible to form a resist pattern that is low in cost, excellent in high resolution, and excellent in depth of focus even when using a lens mounted on an existing apparatus. Therefore, many compositions used for immersion exposure have been reported (for example, Patent Documents 1 to 3).

International Publication No. 04/068242 Pamphlet JP 2005-173474 A JP 2006-48029 A

  However, the lithography technique using immersion exposure has a problem that an acid generator and the like are eluted from the resist film because the resist film directly contacts an immersion exposure solution such as water during exposure. If the amount of the eluted substance is large, there are problems that the lens is damaged, a desired pattern shape cannot be obtained, and sufficient resolution cannot be obtained.

  Further, when water is used as the immersion exposure liquid, there is a problem that when the receding contact angle of water in the resist film is low, water breakage is deteriorated, and in particular, in high-speed scanning exposure, a watermark tends to remain.

  And even if it is a case where the composition of patent documents 1-3 is used, the problem mentioned above is not fully solved, but there exists a problem that the undissolved defect at the time of image development arises especially. This defect is caused by a residue observed on the pattern after development. That is, this is considered to be due to the fact that low-dissolved components such as resin components in the developer aggregate during development and adhere to the pattern.

  The present invention has been made in order to solve the above-described problems of the prior art, can obtain a good pattern shape, and is difficult to elute in an immersion exposure liquid such as water. And a resist pattern forming method using the radiation-sensitive resin composition. The radiation-sensitive resin composition is a resist film material that has a large receding contact angle with respect to the surface and hardly causes development defects.

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

[1] A first polymer (A) having a repeating unit (1) represented by the following general formula (1) and a repeating unit (2) represented by the following general formula (2); A second polymer (B) having an acid dissociable functional group that dissociates by action, the acid dissociable functional group dissociating and becoming alkali-soluble, and a radiation-sensitive acid generator (C) A radiation-sensitive resin composition.

（前記一般式（１）及び前記一般式（２）中、Ｒ^１は、相互に独立に、水素、メチル基、またはトリフルオロメチル基である。前記一般式（１）中、Ｒ^２は、炭素数１〜１０の直鎖状または分岐状の炭化水素基であり、Ｒ^３は単結合または炭素数１〜１０の２価の有機基である。前記一般式（２）中、Ｒ^４及びＲ^５は、相互に独立に、水素原子、炭素数１〜１０の直鎖状若しくは分岐状の炭化水素基、または炭素数３〜１０の環状炭化水素を有する炭素数４〜１５の一価の炭化水素基であって、Ｒ^４とＲ^５の少なくとも１つが前記一価の炭化水素基である。Ｒ^６は単結合または炭素数１〜１０の２価の有機基である。）

(In the general formula (1) and the general formula (2), R ¹ is independently of each other hydrogen, methyl group, or trifluoromethyl group. In the general formula (1), R ² is A straight-chain or branched hydrocarbon group having 1 to 10 carbon atoms, and R ³ is a single bond or a divalent organic group having 1 to 10 carbon atoms, wherein in the general formula (2), R ⁴ and R ⁵ is independently of each other a hydrogen atom, a linear or branched hydrocarbon group having 1 to 10 carbon atoms, or a monovalent C ⁴ to C 15 having a cyclic hydrocarbon having 3 to 10 carbon atoms. A hydrocarbon group, wherein at least one of R ⁴ and R ⁵ is the monovalent hydrocarbon group, and R ⁶ is a single bond or a divalent organic group having 1 to 10 carbon atoms.

[2] The molar ratio of the repeating unit (1) to the repeating unit (2) in the first polymer (A) (the repeating unit (1) / the repeating unit (2)) is 20 / The radiation sensitive resin composition according to [1], which is 80 to 80/20.

[3] The content described in [1] or [2], in which the content of the first polymer (A) is 0.1 to 20 parts by mass with respect to 100 parts by mass of the second polymer (B). Radiation sensitive resin composition.

[4] The radiation sensitive property according to any one of [1] to [3], wherein the acid dissociable functional group of the second polymer (B) is a group having a cyclic hydrocarbon in the structure thereof. Resin composition.

[5] A step (1) of forming a photoresist film on a substrate using the radiation-sensitive resin composition according to any one of [1] to [4], and a liquid on the formed photoresist film An immersion exposure liquid is disposed, and the photoresist film is subjected to immersion exposure through the immersion exposure liquid (2), and the immersion-exposed photoresist film is developed to form a resist pattern. (3) A resist pattern forming method comprising: a step.

  The radiation-sensitive resin composition of the present invention can obtain a good pattern shape, hardly dissolves in an immersion exposure liquid such as water, has a large receding contact angle with the immersion exposure liquid, and causes development defects. This has the effect of being a difficult resist film material.

  The resist pattern forming method of the present invention has an effect that a resist pattern having a good pattern shape 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 are also within the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

[1] Radiation sensitive resin composition:
One embodiment of the radiation-sensitive resin composition of the present invention includes a repeating unit (1) represented by the following general formula (1) (hereinafter sometimes simply referred to as “repeating unit (1)”), and Dissociates from the first polymer (A) containing the repeating unit (2) represented by the following general formula (2) (hereinafter sometimes simply referred to as “repeating unit (2)”) by the action of an acid. It has an acid-dissociable functional group, and contains the second polymer (B) that becomes dissolvable by alkali dissociation and the radiation-sensitive acid generator (C). . Such a radiation sensitive resin composition can obtain a good pattern shape, is difficult to elute in an immersion exposure liquid such as water, has a large receding contact angle with the immersion exposure liquid, and causes development defects. It is a difficult resist film material.

（前記一般式（１）及び前記一般式（２）中、Ｒ^１は、相互に独立に、水素、メチル基、またはトリフルオロメチル基である。前記一般式（１）中、Ｒ^２は、炭素数１〜１０の直鎖状または分岐状の炭化水素基であり、Ｒ^３は単結合または炭素数１〜１０の２価の有機基である。前記一般式（２）中、Ｒ^４及びＲ^５は、相互に独立に、水素原子、炭素数１〜１０の直鎖状若しくは分岐状の炭化水素基、または炭素数３〜１０の環状炭化水素を有する炭素数４〜１５の一価の炭化水素基であって、Ｒ^４とＲ^５の少なくとも１つが前記一価の炭化水素基である。Ｒ^６は単結合または炭素数１〜１０の２価の有機基である。）

(In the general formula (1) and the general formula (2), R ¹ is independently of each other hydrogen, methyl group, or trifluoromethyl group. In the general formula (1), R ² is A straight-chain or branched hydrocarbon group having 1 to 10 carbon atoms, and R ³ is a single bond or a divalent organic group having 1 to 10 carbon atoms, wherein in the general formula (2), R ⁴ and R ⁵ is independently of each other a hydrogen atom, a linear or branched hydrocarbon group having 1 to 10 carbon atoms, or a monovalent C ⁴ to C 15 having a cyclic hydrocarbon having 3 to 10 carbon atoms. A hydrocarbon group, wherein at least one of R ⁴ and R ⁵ is the monovalent hydrocarbon group, and R ⁶ is a single bond or a divalent organic group having 1 to 10 carbon atoms.

  The radiation sensitive resin composition of the present invention is useful as a chemically amplified resist. That is, an acid is generated from the acid generator by exposure, and the acid dissociable group in the second polymer (B) is dissociated by the action of the acid. When the acid-dissociable group is dissociated, a carboxyl group is generated, so that the exposed portion (exposed portion) becomes highly soluble in an alkali developer. Therefore, a positive resist pattern can be obtained by dissolving and removing the exposed portion with an alkaline developer. In particular, an immersion exposure step, that is, a step of exposing an immersion exposure solution (for example, water) having a refractive index higher than that of air at a wavelength of 193 nm by irradiating with radiation between the lens and the resist film is provided. In the resist pattern forming method, it is preferably used as a material for forming a resist film.

[1-1] First polymer (A):
The first polymer (A) is a polymer containing the repeating unit (1) represented by the general formula (1) and the repeating unit (2) represented by the general formula (2) (however, The repeating unit (1) and the repeating unit (2) are not the same). Since the first polymer (A) has a fluorine site in its structure, when added to the resist composition as a component constituting the resist composition, when the resist film is formed by the resist composition Furthermore, the distribution tends to be higher on the resist coating surface due to the oil-repellent characteristics of the first polymer (A) in the coating. Therefore, at the time of immersion exposure, it is possible to suppress the acid generator, the acid diffusion control agent, and the like in the resist film from eluting into the immersion exposure liquid such as water. Furthermore, the receding contact angle between the resist film and the immersion exposure liquid is increased due to the water-repellent characteristics of the first polymer (A). Therefore, water droplets derived from the immersion exposure liquid hardly remain on the resist film, and even when scanning exposure is performed at a high speed, generation of defects such as watermarks due to the immersion exposure liquid can be suppressed.

  Further, when used together with the conventional upper layer film for immersion, elution is further reduced, and the resist is highly water-repellent and can further suppress the occurrence of defects derived from the immersion exposure liquid such as watermark.

In the repeating unit (1), R ² is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, specifically, a propyl group such as a methyl group, an ethyl group, a normal propyl group, or an isopropyl group. , Saturated chain hydrocarbon groups such as 2-methylpropyl group, 2-methylpropyl group and normal butyl group.

R ³ is a single bond or a divalent organic group having 1 to 10 carbon atoms, and is preferably a linear, branched, or cyclic, saturated or unsaturated hydrocarbon group. Specific examples include a propylene group such as a methylene group, an ethylene group, a normal propylene group or an isopropylene group, a saturated chain hydrocarbon group such as a 2-methylpropylene group, a 2-methylpropylene group and a normal butylene group. Can do.

  Examples of the monomer for constituting the repeating unit (1) include monomers represented by the following general formula.

（前記一般式中、Ｒ^１は、相互に独立に、水素、メチル基、またはトリフルオロメチル基である。）

(In the above general formula, R ^{1 s} are independently of each other hydrogen, a methyl group, or a trifluoromethyl group.)

  Among these, the monomer (1-1) represented by the following formula (1-1), the monomer (1-2) represented by the following formula (1-2), and the following formula (1-3) It is preferable to use a monomer (1-3) represented by

  It is preferable that the content rate of a repeating unit (1) is 10-80 mol% with respect to all the repeating units in a 1st polymer (A), and it is still more preferable that it is 30-70 mol%. If the content is less than 10 mol%, the resulting resist film may not be sufficiently maintained in water repellency. On the other hand, if it exceeds 80 mol%, the solubility in the developer becomes too high, and the surface roughness of the resist pattern may increase.

In the repeating unit (2), at least one of R ⁴ and R ⁵ is a monovalent hydrocarbon group having 4 to 15 carbon atoms having a cyclic hydrocarbon having 3 to 10 carbon atoms. Specific examples include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group; a bridged cyclic hydrocarbon ring group such as an adamantyl group. Specific examples of the linear or branched hydrocarbon group having 1 to 10 carbon atoms of R ⁴ and R ⁵ include a propyl group such as a methyl group, an ethyl group, a normal propyl group, or an isopropyl group, A 2-methylpropyl group, a 2-methylpropyl group, a normal butyl group, and the like can be mentioned. Specific examples of the cyclic hydrocarbon having 3 to 10 carbon atoms include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. be able to.

R ⁶ is a single bond or a divalent organic group having 1 to 10 carbon atoms, specifically, a propylene group such as methylene group, ethylene group, normal propylene group or isopropylene group, 2-methylpropylene group, 2 -Saturated chain hydrocarbon groups, such as a methylpropylene group and a normal butylene group, etc. can be mentioned.

  Examples of the monomer for constituting the repeating unit (2) include monomers represented by the following general formula.

（前記一般式中、Ｒ^１は、相互に独立に、水素、メチル基、またはトリフルオロメチル基である。）

(In the above general formula, R ^{1 s} are independently of each other hydrogen, a methyl group, or a trifluoromethyl group.)

  Among these, it is preferable to use the monomer (2-1) represented by the following formula (2-1).

  It is preferable that the content rate of a repeating unit (2) is 10-80 mol% with respect to all the repeating units in a 1st polymer (A), and it is still more preferable that it is 30-70 mol%. If the content is less than 10 mol%, the resulting resist film may not be sufficiently maintained in water repellency. On the other hand, if it exceeds 80 mol%, the solubility in the developer becomes too low, and there is a possibility that undissolved defects during development increase.

  The molar ratio (repeating unit (1) / repeating unit (2)) of the repeating unit (1) and the repeating unit (2) in the first polymer (A) is 20/80 to 80/20. It is more preferable that it is 30 / 70-70 / 30, and it is especially preferable that it is 40 / 60-60 / 40. When the molar ratio is within the above range, a radiation-sensitive resin composition with fewer development defects can be obtained.

  The first polymer (A) can contain other repeating units in addition to the repeating unit (1) and the repeating unit (2). Examples of other repeating units include a repeating unit represented by the general formula (3) described later, a repeating unit containing a lactone skeleton, and the like.

  The content of other repeating units is preferably 10 to 70 mol%, more preferably 15 to 60 mol%, based on 100 mol% of all repeating units in the first polymer (A). Preferably, it is 20-50 mol%, and it is especially preferable. There exists a possibility that the resolution of the formed resist film may fall that the said content rate is less than 10 mol%. On the other hand, if it exceeds 70 mol%, developability and exposure margin may be deteriorated.

  In addition, a 1st polymer (A) may be used individually by 1 type, and may use 2 or more types.

  The content of the first polymer (A) is preferably 0.1 to 20 parts by mass, and 0.5 to 15 parts by mass with respect to 100 parts by mass of the second polymer (B). More preferably. When the content is in the above range, a resist film having a sufficient receding contact angle can be formed, and a resist film in which an acid generator or the like is hardly eluted can be obtained. There exists a possibility that the receding contact angle of the formed resist film may not be enough in the said content being less than 0.1 mass part. In addition, it may be difficult to obtain a resist film from which an acid generator or the like hardly dissolves. On the other hand, if it exceeds 20 parts by mass, when a line and space pattern is formed, the focal depth of an isolated line (line part) may be reduced, or a development defect may occur.

  The first polymer (A) is, for example, in a solvent to which a radical polymerization initiator (for example, hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds, etc.) is added in the presence of a chain transfer agent. The monomer for constituting the repeating unit (1) and the monomer for constituting the repeating unit (2) can be polymerized.

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

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

  The first polymer (A) has a polystyrene-reduced weight average molecular weight (hereinafter sometimes referred to as “Mw”) by a gel permeation chromatography (GPC) method of 1,000 to 50,000. It is preferably 1,000 to 40,000, more preferably 1,000 to 30,000. If the Mw is less than 1,000, a resist film having a sufficient receding contact angle may not be obtained. On the other hand, if it exceeds 50,000, the developability of the resist film may be lowered.

  In the first polymer (A), the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 1 to 5, and more preferably 1 to 4. . In the present specification, the number average molecular weight (Mn) is a polystyrene-reduced number average molecular weight (hereinafter sometimes referred to as “Mn”) by the GPC method.

  The first polymer (A) is more preferable as the content of impurities such as halogen and metal is smaller. When the content of such impurities is small, the sensitivity, resolution, process stability, pattern shape and the like of the resist film can be further improved.

  Examples of the purification method for the first polymer (A) include chemical purification methods such as washing with water and liquid-liquid extraction, and these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation. A combined method and the like can be given.

  Examples of the solvent used for liquid-liquid extraction include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane, methanol, ethanol, 2-propanol, and 2-propanol. And alcohols such as 4-methyl-2-pentanol, and ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, and 2-heptanone. Among these, n-hexane, n-heptane, methanol, ethanol, acetone, and 2-butanone are preferable.

[1-2] Second polymer (B):
The second polymer (B) has an acid dissociable functional group that dissociates by the action of an acid, and the acid dissociable functional group dissociates to become alkali-soluble. The second polymer (B) is not particularly limited as long as it has the acid dissociable functional group, but the acid dissociable functional group is a group having a cyclic hydrocarbon in its structure. It is preferable. Such a second polymer (B) has an advantage that the sensitivity increases because the acid-dissociable functional group is easily dissociated.

  Examples of the group having a cyclic hydrocarbon in the structure include 2- (2-methyl) cyclopentyl group, 2- (2-ethyl) cyclopentyl group, 2- (2-n-propyl) cyclopentyl group, 2- ( 2-isopropyl) cyclopentyl group, 2- (2-methyl) cyclohexyl group, 2- (2-ethyl) cyclohexyl group, 2- (2-methyl) cyclooctyl group, 2- (2-ethyl) cyclooctyl group, 2 -(2-methyl) adamantyl group, 2- (2-ethyl) adamantyl group, 2- (2-n-propyl) adamantyl group, 2- (2-isopropyl) adamantyl group, and these alicyclic rings Groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, 2-methylpropyl, 2-methylpropyl, t-butyl, etc. Prime 1-4 linear, mention may be made of substituted group with one or more branched or cyclic alkyl group or 1 or more. Among these, ethylcyclopentyl is preferable because of the advantage that the acid-dissociable functional group is easily dissociated.

  Specifically, as the second polymer (B), a polymer having an alicyclic skeleton such as a norbornane ring in the main chain obtained by polymerizing a norbornene derivative or the like, a copolymer of norbornene derivative and maleic anhydride is copolymerized. A polymer having a norbornane ring and a maleic anhydride derivative in the main chain, and a polymer having a norbornane ring and a (meth) acryl skeleton in the main chain obtained by copolymerizing a norbornene derivative and a (meth) acrylic compound , A polymer in which norbornane ring, maleic anhydride derivative and (meth) acryl skeleton are mixed in the main chain obtained by copolymerizing norbornene derivative with maleic anhydride and (meth) acrylic compound, and (meth) acrylic compound are copolymerized A polymer having a (meth) acryl skeleton as the main chain obtained in this manner can be used. Note that “(meth) acryl” is one or both of “acryl” and “methacryl”.

  The second polymer (B) contains a repeating unit represented by the following general formula (3) having an acid-dissociable functional group (hereinafter sometimes referred to as “repeating unit (3)”). Is preferred.

（上記一般式（３）中、Ｒ^７は水素、メチル基、またはトリフルオロメチル基である。Ｒ^８は、相互に独立に、炭素数４〜２０の１価の脂環式炭化水素基若しくはその誘導体、または炭素数１〜４の直鎖状若しくは分岐状のアルキル基である。或いは、いずれか２つのＲ^８が相互に結合して、それぞれが結合している炭素原子と共に２価の脂環式炭化水素基またはその誘導体を形成している。）

(In the general formula (3), R ⁷ is hydrogen, a methyl group, or a trifluoromethyl group. R ⁸ is independently a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or A derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms, or any two R ⁸ 's bonded to each other, together with the carbon atom to which each is bonded, A cyclic hydrocarbon group or a derivative thereof is formed.)

In the general formula (3), examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms of R ⁸ include norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, Groups composed of alicyclic rings derived from cycloalkanes such as cycloheptane and cyclooctane; groups composed of these alicyclic rings are, for example, methyl group, ethyl group, n-propyl group, i-propyl group 1 or more or 1 or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as n-butyl group, 2-methylpropyl group, 2-methylpropyl group and t-butyl group. Examples include substituted groups.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms of R ⁸ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, Examples thereof include 2-methylpropyl group and t-butyl group.

When any two R ⁸ are bonded to each other to form a divalent alicyclic hydrocarbon group or a derivative thereof together with the carbon atom to which each is bonded, a divalent alicyclic hydrocarbon group Or, as a derivative thereof, for example, a group consisting of an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane, or a group consisting of these alicyclic rings is the alkyl group described above. And the like can be mentioned.

Specific examples of “—C (R ⁸ ) ₃ ” in the general formula (3) include t-butyl group, 2-n- (2-ethyl-2-methyl) propyl group, 2-n- ( 1,2-dimethyl) propyl group, 2-n- (1,2-dimethyl) butyl group, 2-n- (1,2-dimethyl) pentyl group, 2- (1,2-diethyl) propyl group, 2 -N- (1,2-diethyl) butyl group, 2-n- (1,2-diethyl) pentyl group, 2- (2-methyl) cyclopentyl group, 2- (2-ethyl) cyclopentyl group, 2- ( 2-n-propyl) cyclopentyl group, 2- (2-isopropyl) cyclopentyl group, 2- (2-methyl) cyclohexyl group, 2- (2-ethyl) cyclohexyl group, 2- (2-methyl) cyclooctyl group, 2- (2-ethyl) cyclooctyl group, 2- (2-methyl) ) Adamantyl group, 2- (2-ethyl) adamantyl group, 2- (2-n-propyl) adamantyl group, 2- (2-isopropyl) adamantyl group, and a group consisting of these alicyclic rings, for example, C1-C4 linear or branched such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 2-methylpropyl group, t-butyl group And a group substituted with one or more of cyclic or cyclic alkyl groups.

Specific examples of the monomer for constituting the repeating unit (3) include (meth) acrylic acid 2-methyladamantan-2-yl ester and (meth) acrylic acid 2-methyl-3-hydroxyadamantane-2. -Yl ester, (meth) acrylic acid 2-ethyladamantan-2-yl ester, (meth) acrylic acid 2-ethyl-3-hydroxyadamantan-2-yl ester, (meth) acrylic acid 2-n-propyladamantane- 2-yl ester, (meth) acrylic acid 2-isopropyladamantan-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 2- (bicyclo [2.2.1] hept-2-yl) -2-methylethyl ester, (meth) acrylic acid 2- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yl) -2-methyl ethyl ester, (meth) acrylic acid 2- (tetracyclo ^[6.2.1 3,6 ^{.0 2,7]} dodecane-4-yl) -2-methyl ethyl ester, (Meth) acrylic acid 2- (adamantan-2-yl) -2-methylethyl ester, (meth) acrylic acid 2- (3-hydroxyadamantan-2-yl) -2-methylethyl ester, (meth) acrylic acid 1,2-dicyclohexylethyl ester, (meth) acrylic acid 1,2-di (bicyclo [2.2.1] hept-2-yl) ethyl ester, (meth) acrylic acid 1,2-di (tricyclo) 5.2.1.0 ^2,6] decan-8-yl) ethyl ester, (meth) acrylic acid 1,2-di (tetracyclo ^[6.2.1 3,6 ^{.0 2,7]} dodecane -4 -Yl) ethyl ester, (meth) acrylic acid 1,2-di (adamantan-2-yl) ethyl ester, (meth) acrylic acid 2-methyl-2-cyclopentyl ester, (meth) acrylic acid 2-ethyl-2 -Cyclopentyl ester, (meth) acrylic acid 2-methyl-2-cyclohexyl ester, (meth) acrylic acid 2-ethyl-2-cyclohexyl ester, and the like.

  Among these monomers, (meth) acrylic acid 2-methyladamantan-2-yl ester, (meth) acrylic acid 2-ethyladamantan-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 2- (bicyclo [2.2. 1] hept-2-yl) -2-methylethyl ester, (meth) acrylic acid 2- (adamantan-2-yl) -2-methylethyl ester, (meth) acrylic acid 2-methyl-2-cyclopentyl ester, (Meth) acrylic acid 2-ethyl-2-cyclopentyl ester, (meth) acrylic acid 2-methyl-2-cyclohexyl ester, (meth) acrylic acid 2-e Le 2-cyclohexyl ester.

  In addition, the repeating unit (3) may be contained individually by 1 type, and may contain 2 or more types.

  The content of the repeating unit (3) is preferably 10 to 70 mol%, preferably 15 to 60 mol%, based on 100 mol% of all repeating units in the second polymer (B). More preferably, it is 20-50 mol%, and it is especially preferable. There exists a possibility that the resolution of the formed resist film may fall that the said content rate is less than 10 mol%. On the other hand, if it exceeds 70 mol%, developability and exposure margin may be deteriorated.

  The second polymer (B) preferably further has a repeating unit containing a lactone skeleton (hereinafter sometimes referred to as “repeating unit (4)”). By having such a repeating unit (4), there is an advantage that the adhesion of the resist film to the substrate is improved.

  Examples of the monomer for constituting the repeating unit (4) include monomers represented by the following general formulas (4-1) to (4-6).

In General Formulas (4-1) to (4-6), R ⁹ is independently a hydrogen atom or a methyl group. In General Formula (4-1), R ¹⁰ is a hydrogen atom or an alkyl group that may have a substituent having 1 to 4 carbon atoms. In General Formula (4-4) and General Formula (4-5), R ¹¹ is a hydrogen atom or a methoxy group. In general formula (4-2) and general formula (4-3), A is a single bond or a methylene group. In general formulas (4-3) and (4-5), B represents an oxygen atom or a methylene group. In general formula (4-1), l is an integer of 1-3. In general formula (4-2) and general formula (4-3), m is 0 or 1.

Examples of the alkyl group which may have a substituent having 1 to 4 carbon atoms of R ¹⁰ include, for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and a 2-methylpropyl group. , 2-methylpropyl group, t-butyl group and the like.

As a monomer for constituting the repeating unit (4), in addition to the monomers represented by the above general formulas (4-1) to (4-6), for example, (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 este , (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-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5,5-dimethyl-2-oxotetrahydrofuran-3 -Yl ester, (meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-3,3-dimethyl-5 -Oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid- , May be mentioned 4-dimethyl-5-oxo-tetrahydrofuran-2-yl methyl ester.

  In addition, the repeating unit (4) may be contained individually by 1 type, and may contain 2 or more types.

  The content of the repeating unit (4) is preferably 5 to 85 mol%, more preferably 10 to 70 mol%, based on 100 mol% of all repeating units in the second polymer (B). More preferably, it is 15-60 mol%, and it is especially preferable. There exists a possibility that the adhesiveness at the time of image development may deteriorate that the said content rate is less than 5 mol%. On the other hand, if it exceeds 85 mol%, the solubility of the second polymer (B) in the solvent may be deteriorated, and the resolution may be deteriorated.

  The second polymer (B) is, for example, in a solvent to which a radical polymerization initiator (for example, hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds, etc.) is added in the presence of a chain transfer agent. Thus, it can be produced by polymerizing the monomer for constituting the repeating unit (3) and the monomer for constituting the repeating unit (4).

  Examples of the solvent used for the polymerization of the second polymer (B) include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane and n-decane; cyclohexane, cyclohexane Cycloalkanes such as heptane, cyclooctane, decalin, norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; halogens such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene Hydrocarbons; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone and 2-heptanone Tetrahydrofuran, dimethoxyethanes, diethoxyethanes And the like ethers. In addition, these solvent may contain individually by 1 type and may contain 2 or more types.

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

  The second polymer (B) preferably has an Mw by GPC method of 1,000 to 100,000, more preferably 1,000 to 30,000, and 1,000 to 20,000. It is particularly preferred. There exists a possibility that the heat resistance of the formed resist film may fall that said Mw is less than 1,000. On the other hand, if it exceeds 100,000, the developability of the formed resist film may be lowered.

  In the second polymer (B), the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 1 to 5, and more preferably 1 to 3. .

  The second polymer (B) is a low molecular weight component derived from the monomer used in preparing the second polymer (B) (hereinafter referred to as “low molecular weight component (b)”). The content ratio is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, based on 100% by mass of the second polymer (B) in terms of solid content. It is particularly preferably 0.05% by mass or less. Thus, when the content ratio is 0.1% by mass or less, the amount of the eluate that is eluted with respect to the immersion exposure liquid such as water in contact with the resist film during the immersion exposure can be reduced. it can. Furthermore, it is difficult to generate foreign matters during storage of the radiation-sensitive resin composition, it is difficult to cause uneven coating during application, and it is possible to satisfactorily suppress the occurrence of defects during resist pattern formation.

  The low molecular weight component (b) is a component having a weight average molecular weight of 500 or less, and examples thereof include monomers, dimers, trimers, and oligomers. The low molecular weight component (b) is, for example, a chemical purification method such as washing with water, liquid-liquid extraction, or a combination of these chemical purification methods and a physical purification method such as ultrafiltration or centrifugation. Can be removed.

  In addition, a 2nd polymer (B) 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 and the like of the resist film can be further improved.

  Examples of the purification method for the second polymer (B) include the above-described chemical purification methods such as washing and liquid-liquid extraction, and these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation. The method etc. which combined these can be mentioned.

  In addition, the 2nd polymer (B) may contain individually by 1 type, and may contain 2 or more types.

[1-3] Radiation sensitive acid generator (C):
The radiation-sensitive acid generator (C) (hereinafter sometimes simply referred to as “acid generator (C)”) generates an acid upon exposure. Therefore, in the resist film formed by the radiation-sensitive resin composition of the present invention, the acid generator (C) generates an acid in the exposed portion (exposed portion). Then, due to the action of this acid, the acid dissociable functional group of the second polymer (B) in the exposed area is dissociated from the second polymer (B), and the second weight of the acid dissociable functional group is dissociated. The coalescence (B) becomes readily soluble in an alkali developer. Therefore, a desired positive resist pattern can be obtained by removing the second polymer (B) (that is, the exposed portion of the resist film) with an alkali developer.

  The acid generator (C) is not particularly limited as long as it has the above action, and examples thereof include compounds represented by the following general formula (5) and other acid generators. Among these, what contains the compound represented by following General formula (5) is preferable.

In General Formula (5), R ¹² is a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched alkoxyl group having 1 to 10 carbon atoms. Or a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms. R ¹³ is a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkoxyl group having 1 to 10 carbon atoms, or a linear or branched group having 1 to 10 carbon atoms, Or it is a cyclic alkanesulfonyl group. R ¹⁴ is each independently a linear or branched alkyl group having 1 to 10 carbon atoms, an optionally substituted phenyl group or an optionally substituted naphthyl group, or two R ¹⁴ is a divalent group having 2 to 10 carbon atoms which may be bonded to each other and substituted. k is an integer of 0-2. X ⁻ represents general formula (6): R ¹⁵ C _n F _2n SO ₃ ⁻ , general formula (7): R ¹⁶ SO ₃ ⁻ (in general formula (6) and general formula (7), R ¹⁵ and R ¹⁶ Are each independently a fluorine atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms, and in general formula (6), n is an integer of 1 to 10). It is an anion represented by (8-1) or general formula (8-2). r is an integer of 0-10.

（一般式（８−１）及び一般式（８−２）中、Ｒ^１７は、相互に独立に、フッ素原子を有する炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、または２つのＲ^１７が結合して、置換基を有してもよい、フッ素原子を有する炭素数２〜１０の２価の有機基である。）

(In General Formula (8-1) and General Formula (8-2), R ¹⁷ is, independently of each other, a linear or branched alkyl group having 1 to 10 carbon atoms having a fluorine atom, or two R ¹⁷ is a divalent organic group having 2 to 10 carbon atoms having a fluorine atom, which may have a substituent.

In the general formula (5), examples of the linear or branched alkyl group having 1 to 10 carbon atoms of R ¹² include a methyl group, an ethyl group, an n-butyl group, a 2-methylpropyl group, and 2-methyl. A propyl group, a t-butyl group, an n-pentyl group, etc. can be mentioned. Among these, a methyl group, an ethyl group, an n-butyl group, and a t-butyl group are preferable. Incidentally, a linear or branched alkyl group having 1 to 10 carbon atoms and R ¹³ and R ¹⁴ also may be exemplified by the same.

Examples of the linear or branched alkoxyl group having 1 to 10 carbon atoms of R ¹² include, for example, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group. Group, 2-methylpropoxy group, t-butoxy group and the like. Among these, a methoxy group, an ethoxy group, an n-propoxy group, and an n-butoxy group are preferable. Incidentally, it is possible to a straight-chain or branched alkoxy group having 1 to 10 carbon atoms R ¹³ also illustrates what similar.

Examples of the linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms of R ¹² include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, and an n-butoxycarbonyl group. Group, 2-methylpropoxycarbonyl group, 2-methylpropoxycarbonyl group, t-butoxycarbonyl group and the like. Among these, a methoxycarbonyl group, an ethoxycarbonyl group, and an n-butoxycarbonyl group are preferable.

Examples of the linear, branched, or cyclic alkanesulfonyl group having 1 to 10 carbon atoms of R ¹³ include, for example, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a tert. -A butanesulfonyl group, a cyclopentanesulfonyl group, a cyclohexanesulfonyl group, etc. can be mentioned. Among these, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group, and a cyclohexanesulfonyl group are preferable.

  In addition, r is an integer of 0 to 10 as described above, but is preferably an integer of 0 to 2.

Examples of the optionally substituted phenyl group for R ¹⁴ include a phenyl group such as a phenyl group, a 4-ethylphenyl group, a 4-t-butylphenyl group, a 4-cyclohexylphenyl group, and a 4-fluorophenyl group, or A phenyl group substituted with a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms; these phenyl group or alkyl-substituted phenyl group can be substituted with an alkoxyl group, an alkoxyalkyl group, an alkoxycarbonyl group, or an alkoxycarbonyloxy group; And a group substituted with at least one group such as a hydroxyl group, a carboxyl group, a cyano group, and a nitro group.

  Among the substituents for the phenyl group or the alkyl-substituted phenyl group, examples of the alkoxyl group include, for example, a methoxy group, an ethoxy group, an n-propoxy group, a t-butoxy group, a cyclopentyloxy group, a cyclohexyloxy group, and the like. The linear, branched, or cyclic alkoxyl group can be exemplified.

  Examples of the alkoxyalkyl group include linear chains having 2 to 21 carbon atoms such as a methoxymethyl group, an ethoxymethyl group, a 2-methoxyethyl group, a 2-methoxyethyl group, a 2-ethoxyethyl group, and a 2-ethoxyethyl group. , Branched or cyclic alkoxyalkyl groups, and the like.

  Examples of the alkoxycarbonyl group include methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, i-propoxycarbonyl group, n-butoxycarbonyl group, 2-methylpropoxycarbonyl group, 2-methylpropoxycarbonyl group, t- Examples thereof include linear, branched or cyclic alkoxycarbonyl groups having 2 to 21 carbon atoms such as butoxycarbonyl group, cyclopentyloxycarbonyl group, cyclohexyloxycarbonyl and the like.

  Examples of the alkoxycarbonyloxy group include a methoxycarbonyloxy group, an ethoxycarbonyloxy group, an n-propoxycarbonyloxy group, an i-propoxycarbonyloxy group, an n-butoxycarbonyloxy group, a t-butoxycarbonyloxy group, and a cyclopentyloxycarbonyl. And a straight chain, branched or cyclic alkoxycarbonyloxy group having 2 to 21 carbon atoms such as a group and cyclohexyloxycarbonyl.

Among the optionally substituted phenyl groups for R ¹⁴ , a phenyl group, a 4-cyclohexylphenyl group, a 4-t-butylphenyl group, a 4-methoxyphenyl group, and a 4-t-butoxyphenyl group are preferable.

Examples of the optionally substituted naphthyl group for R ¹⁴ include 2-naphthyl group, 2-methyl-2-naphthyl group, 3-methyl-2-naphthyl group, 4-methyl-2-naphthyl group, 4- Methyl-2-naphthyl group, 5-methyl-2-naphthyl group, 6-methyl-2-naphthyl group, 7-methyl-2-naphthyl group, 8-methyl-2-naphthyl group, 2,3-dimethyl-2 -Naphthyl group, 2,4-dimethyl-2-naphthyl group, 2,5-dimethyl-2-naphthyl group, 2,6-dimethyl-2-naphthyl group, 2,7-dimethyl-2-naphthyl group, 2, 8-dimethyl-2-naphthyl group, 3,4-dimethyl-2-naphthyl group, 3,5-dimethyl-2-naphthyl group, 3,6-dimethyl-2-naphthyl group, 3,7-dimethyl-2- Naphthyl group, 3,8-dimethyl-2-naphthyl Group, 4,5-dimethyl-2-naphthyl group, 5,8-dimethyl-2-naphthyl group, 4-ethyl-2-naphthyl group, 2-naphthyl group, 2-methyl-2-naphthyl group, 3-methyl- A naphthyl group substituted with a naphthyl group such as a 2-naphthyl group or 4-methyl-2-naphthyl group or a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms; these naphthyl groups or alkyl substitutions; And a group in which a naphthyl group is substituted with at least one group such as a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group. it can.

  Examples of the substituent for substituting the naphthyl group or the alkyl-substituted naphthyl group include the same substituents as those exemplified as the substituent for the phenyl group or the alkyl-substituted phenyl group.

Among the optionally substituted naphthyl groups of R ¹⁶ , a 2-naphthyl group, a 2- (4-methoxynaphthyl) group, a 2- (4-ethoxynaphthyl) group, a 2- (4-n-propoxynaphthyl) group, 2- (4-n-butoxynaphthyl) group, 2- (7-methoxynaphthyl) group, 2- (7-ethoxynaphthyl) group, 2- (7-n-propoxynaphthyl) group, 2- (7-n -Butoxynaphthyl) group is preferred.

Examples of the divalent group having 2 to 10 carbon atoms, in which the two R ¹⁴ described above may be bonded to each other, include a 5-membered ring or a sulfur atom in the compound represented by the general formula (5) A group that forms a 6-membered ring is preferable, and a group that forms a 5-membered ring (that is, a tetrahydrothiophene ring) is more preferable.

  Examples of the substituent of the divalent group having 2 to 10 carbon atoms include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group. be able to.

Among R ¹⁴ described above, a methyl group, an ethyl group, a phenyl group, a 4-methoxyphenyl group, and a 2-naphthyl group are preferable, and two R ^14s are bonded to each other to form a tetrahydrothiophene ring structure together with a sulfur atom. It is also preferable that it is a divalent group.

When X ⁻ is an anion represented by the general formula (6): R ¹⁵ C _n F _2n SO ₃ ^— , among these, “—C _n F _2n —” is a perfluoroalkylene group having n carbon atoms. However, this group may be linear or branched. Here, n is preferably 1, 2, 4 or 8.

The optionally substituted good C1-12 hydrocarbon group R ^15, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, a bridged alicyclic hydrocarbon group. Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, norbornyl group, norbornylmethyl group, hydroxy A norbornyl group and an adamantyl group are preferred. Incidentally, it is possible to hydrocarbon groups substituted carbon atoms and optionally from 1 to 12 R ¹⁶ also illustrates what similar.

In general formula (8-1), examples of the linear or branched alkyl group having 1 to 10 carbon atoms having a fluorine atom represented by R ¹⁷ include a trifluoromethyl group, a pentafluoroethyl group, and a heptafluoropropyl group. , Nonafluorobutyl group, dodecafluoropentyl group, perfluorooctyl group and the like. Further, by bonding two R ¹⁷ in R ^17, which may have a substituent, examples of the divalent organic group having 2 to 10 carbon atoms having a fluorine atom, for example, tetrafluoroethylene group, hexafluoropropylene A propylene group, an octafluorobutylene group, a decafluoropentylene group, an undecafluorohexylene group, etc. can be mentioned. Incidentally, in the general formula ^{(8-2), R 17} can also be mentioned as similar.

X ^- is specifically, trifluoromethanesulfonate anion, perfluoro -n- butane sulfonate anion, perfluoro -n- octanesulfonate anion, 2-bicyclo [2.2.1] hept-2-yl -1, 1,2,2-tetrafluoroethanesulfonate anion, 2-bicyclo [2.2.1] hept-2-yl-1,2-difluoroethanesulfonate anion, represented by the following formulas (9-1) to (9-7) The anion represented is preferred.

  Specific examples of the compound represented by the general formula (5) include triphenylsulfonium trifluoromethanesulfonate, tri-tert-butylphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium trifluoromethanesulfonate, and 4-methane. Sulfonylphenyl-diphenylsulfonium trifluoromethanesulfonate, 2- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 2- (4-n-butoxynaphthyl) tetrahydrothiophenium trifluoromethanesulfonate,

  Triphenylsulfonium perfluoro-n-butanesulfonate, tri-tert-butylphenylsulfonium perfluoro-n-butanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium per Fluoro-n-butanesulfonate, 2- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-butanesulfonate, 2- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro- n-butanesulfonate,

  Triphenylsulfonium perfluoro-n-octane sulfonate, tri-tert-butylphenylsulfonium perfluoro-n-octane sulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-octane sulfonate, 4-methanesulfonylphenyl-diphenylsulfonium per Fluoro-n-octanesulfonate, 2- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 2- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro- n-octane sulfonate,

  Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2 .1] Hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl)- 1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoro Ethanesulfonate, 2- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- (bicyclo [2.2. ] Hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 2- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,1,2,2-tetrafluoroethanesulfonate,

  Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,2-difluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,2-difluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,2-difluoroethanesulfonate, 4-methanesulfonylphenyl -Diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,2-difluoroethanesulfonate, 2- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- ( Bicyclo [2.2.1] hepta-2'-yl) -1,2-difluoroeta Sulfonate, 2- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2′-yl) -1,2-difluoroethanesulfonate, the following formula (10-1) to The compound etc. which are represented by (10-15) can be mentioned. In addition, the compound represented by General formula (5) may be used individually by 1 type, and may use 2 or more types.

  Examples of other acid generators include onium salt compounds, halogen-containing compounds, diazoketone compounds, sulfone compounds, and sulfonic acid compounds. In addition, these compounds may be used individually by 1 type, and may use 2 or more types.

  Content of a radiation sensitive acid generator (C) is 0.1-20 mass parts with respect to a total of 100 mass parts of a 1st polymer (A) and a 2nd polymer (B). Is preferable, and it is still more preferable that it is 0.5-10 mass parts. When the content is in the above range, the sensitivity and developability of the formed film can be maintained. There exists a possibility that a sensitivity and developability may fall that the said content is less than 0.1 mass part. On the other hand, if it exceeds 20 parts by mass, the transparency to radiation is lowered, and it may be difficult to obtain a rectangular resist pattern.

  In addition, when using the compound represented by General formula (5) and another acid generator, the content rate of another acid generator is the compound represented by General formula (5), and another acid generator. It is preferable that it is 80 mass% or less with respect to a total of 100 mass%, and it is still more preferable that it is 60 mass% or less. There exists a possibility that a sensitivity may fall that the content rate of said other acid generator is more than 80 mass%.

[1-4] Other components:
In addition to the first polymer (A), the second polymer (B), and the radiation-sensitive acid generator (C), the radiation-sensitive resin composition of the present invention contains nitrogen as necessary. A compound, a solvent, and various additives (for example, an alicyclic additive, a surfactant, a sensitizer, and the like) can be contained.

[1-4-1] Nitrogen-containing compound:
The nitrogen-containing compound is a component having an action of controlling a diffusion phenomenon of an acid generated from an acid generator upon exposure in a resist film and suppressing an undesirable chemical reaction in a non-exposed region. By blending such a nitrogen-containing compound, the storage stability of the resulting radiation-sensitive resin composition can be improved. In addition, the resolution can be further improved, and a change in the line width of the resist pattern due to fluctuations in the holding time (PED) from exposure to heat treatment after exposure can be suppressed. Therefore, a radiation sensitive resin composition having extremely excellent process stability can be obtained.

  Examples of nitrogen-containing compounds include tertiary amine compounds, amine compounds other than tertiary amine compounds (other amine compounds), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

  Examples of the tertiary amine compound include mono (cyclo) alkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, cyclohexylamine, di-n-butylamine, Di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, cyclohexylmethylamine, dicyclohexylamine and the like ( Cyclo) alkylamines; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri -N-nonylamine, tri-n-decylamine, cyclohexyl Tri (cyclo) alkylamines such as methylamine, methyldicyclohexylamine, tricyclohexylamine; substituted alkylamines such as 2,2 ′, 2 ″ -nitrotriethanol; aniline, N-methylaniline, N, N-dimethylaniline 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, naphthylamine, 2,4,6-tri-tert-butyl-N-methylaniline, N-phenyldiethanolamine 2,6-diisopropylaniline.

  Examples of other amine compounds include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4 , 4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- ( 4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis [2- (4-aminophenyl)- 2-methylethyl] benzene, 1,3-bis [2- (4-aminophenyl) -2-methylethyl Benzene, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether, 2- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′, N Examples include '-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, and the like.

  Examples of the amide group-containing compound include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt- Butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-2-adamantylamine, (S)-( -)-2- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-2- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonyl Perazine, Nt-butoxycarbonylpiperidine, N, N-di-t-butoxycarbonyl-2-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-2-adamantylamine, Nt- Butoxycarbonyl-4,4′-diaminodiphenylmethane,

  N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N′N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N′-di-t-butoxycarbonyl-1,7- Diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxy Carbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminododecane, N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, N— t-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phen Nt-butoxycarbonyl group-containing amino compounds such as rubenzimidazole, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide Pyrrolidone, N-methylpyrrolidone, N-acetyl-2-adamantylamine, isocyanuric acid tris (2-hydroxyethyl) and the like.

  Examples of urea compounds include urea, methylurea, 1,2-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea. Etc.

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

  In addition, a nitrogen-containing compound may be used individually by 1 type, and can also use 2 or more types.

  It is preferable that the compounding quantity of a nitrogen-containing compound is 15 mass parts or less with respect to 100 mass parts in total of a 1st polymer (A) and a 2nd polymer (B), and is 10 mass parts or less. More preferably, the amount is 5 parts by mass or less. In this case, when the compounding amount of the nitrogen-containing compound is more than 15 parts by mass, the sensitivity of the formed resist film may be lowered. In addition, there exists a possibility that pattern shape and dimension fidelity may fall that the compounding quantity of a nitrogen-containing compound is less than 0.001 mass part depending on process conditions.

[1-4-2] Solvent:
The solvent is not particularly limited as long as it dissolves the first polymer (A) and the second polymer (B) to make the radiation-sensitive resin composition of the present invention in solution. For example, 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-methyl-2-pentanone, 3,3-dimethyl-2-butanone, 2- Linear or branched ketones such as heptanone and 2-octanone; cyclic ketones such as cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone and isophorone; Propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-i-propyl ether acetate, propylene glycol mono-n-butyl ether acetate, pro Glycol monobutyl -i- ether acetate, propylene glycol monobutyl -sec- butyl ether acetate, propylene glycol monoalkyl ether acetates such as propylene glycol monobutyl -t- butyl ether acetate;

  Methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, n-propyl 2-hydroxypropionate, i-propyl 2-hydroxypropionate, n-butyl 2-hydroxypropionate, i-butyl 2-hydroxypropionate, Alkyl 2-hydroxypropionates such as sec-butyl 2-hydroxypropionate and t-butyl 2-hydroxypropionate; methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3- Alkyl 3-alkoxypropionates such as ethyl ethoxypropionate,

  n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclohexanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether , Diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, propylene glycol monomethyl ether , Propylene glycol monoethyl Ether, propylene glycol mono -n- propyl ether, toluene, xylene,

  Ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3 -Methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate, ethyl pyruvate, N-methyl Pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, benzyl ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, caproic acid, caprylic acid, 2-octanol, 2-nona Lumpur, benzyl alcohol, ethyl benzyl acetate, benzoate, diethyl oxalate, diethyl maleate, .gamma.-butyrolactone, ethylene carbonate, propylene carbonate and the like. In addition, a solvent may be used individually by 1 type and may use 2 or more types.

  Among these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, and γ-butyrolactone are preferable.

  The solvent is preferably added so that the total solid concentration of the radiation-sensitive resin composition of the present invention is 1 to 50% by mass (more preferably 1 to 25% by mass). The radiation sensitive resin composition of the present invention can be used as a composition solution by adding a solvent and then filtering with a filter having a pore size of about 0.2 μm, for example.

[2] Method for forming resist pattern:
The resist pattern forming method of the present invention includes (1) a step of forming a photoresist film on a substrate using the above-described radiation-sensitive resin composition of the present invention, and a liquid for immersion exposure on the photoresist film. And (2) a step of immersion exposure of the photoresist film through a liquid for immersion exposure, and (3) a step of developing the photoresist film subjected to immersion exposure to form a resist pattern. Is the method. According to such a forming method, a resist pattern having a good pattern shape can be formed.

  In the resist pattern forming method of the present invention, first, the step (1) of forming a photoresist film on a substrate using the radiation-sensitive resin composition of the present invention is performed. Specifically, a photoresist film is formed by applying a radiation sensitive resin composition on a substrate. Examples of the method for applying the radiation sensitive resin composition include spin coating, cast coating, roll coating, and the like. Examples of the substrate include a silicon wafer and a wafer coated with aluminum.

  Next, a liquid immersion exposure liquid is disposed on the photoresist film, and the photoresist film is subjected to liquid immersion exposure (2) through the liquid immersion exposure liquid.

  As the liquid for immersion exposure, for example, pure water, a long chain or cyclic aliphatic compound, or the like can be used. For example, radiation can be used as the exposure light for the immersion exposure. The radiation can be appropriately selected according to the type of acid generator in the radiation-sensitive resin composition, and examples thereof include visible light, ultraviolet light, far ultraviolet light, X-rays, and charged particle beams. Can do. Among these, far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser (wavelength 193 nm) is particularly preferable. In addition, exposure conditions, such as exposure amount, can be suitably selected according to the compounding composition of a radiation sensitive resin composition, the kind of additive, etc.

  Next, the photoresist film that has been subjected to immersion exposure is developed to form a resist pattern (3). A predetermined resist pattern can be formed by development. Examples of the developer used for this development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-propyl. Amine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo -An alkaline aqueous solution in which at least one of alkaline compounds such as [4.3.0] -5-nonene is dissolved is preferable.

  The concentration of the alkaline aqueous solution is preferably 10% by mass or less. If the concentration of the alkaline aqueous solution is more than 10% by mass, the unexposed area may be dissolved in the developer.

  For example, an organic solvent can be added to the developer composed of an 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. In addition, an organic solvent may be used individually by 1 type, and may use 2 or more types.

  It is preferable that the usage-amount of an organic solvent is 100 volume% or less with respect to alkaline aqueous solution. If the amount of the organic solvent used is more than 100% by volume, the developability is lowered, and there is a risk that the remaining development in the exposed area will increase. In addition, an appropriate amount of a surfactant or the like can be added to the developer composed of an alkaline aqueous solution.

  After development, the film is washed with water and dried. Moreover, it is preferable to perform heat processing (PEB) after exposure. By PEB, there exists an advantage that the dissociation reaction of the acid dissociable group in a resin component advances smoothly. The heating conditions for PEB vary depending on the composition of the radiation-sensitive resin composition, but are preferably 30 to 200 ° C, and more preferably 50 to 170 ° C. In addition, the resist film can be heat-treated (hereinafter referred to as “PB”) before exposure. The heating conditions for PB can be the same as the heating conditions for PEB.

  Further, in order to maximize the potential of the radiation-sensitive resin composition, for example, as disclosed in Japanese Patent Publication No. 6-12452 (Japanese Patent Laid-Open No. 59-93448) and the like, a substrate to be used is used. An organic or inorganic antireflection film can also be formed thereon. And in order to prevent the influence of the basic impurity etc. which are contained in environmental atmosphere, a protective film can also be provided on a resist film as disclosed by Unexamined-Japanese-Patent No. 5-188598 etc., for example. Further, in order to prevent the acid generator or the like from flowing out of the resist film, a liquid immersion protective film can be provided on the resist film as disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-352384. These techniques can be used in combination.

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

(1) Mw and Mn:
Gel permeation using monodisperse polystyrene as a standard under the analytical conditions of GPC column (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, flow rate 1.0 ml / min, elution solvent tetrahydrofuran, column temperature 40 ° C. It was measured by chromatography (GPC). Further, the degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

(2) Amount of low molecular weight component derived from monomer:
Using an “Intersil ODS-25 μm column (4.6 mmφ × 250 mm)” manufactured by GL Sciences, a flow rate of 1.0 ml / min, and an elution solvent using acrylonitrile / 0.1% phosphoric acid aqueous solution as a high speed It was measured at a detection wavelength of 254 nm by liquid chromatography (HPLC). The results are shown in terms of mass% of the low molecular weight component relative to the total resin (total amount of the first polymer (A) and the second polymer (B)) being 100 mass%. “Low molecular weight” means a component having a weight average molecular weight of 500 or less.

  The compounds used as monomers in Synthesis Examples 1 to 8 are shown below.

(Synthesis Example 1)
First, 50 mol% of the compound (M-3) represented by the above formula (M-3) as a monomer, 50 mol% of the compound (M-5) represented by the above formula (M-5), and A monomer solution in which an initiator (dimethyl-2,2′-azobisisobutyrate (MAIB)) was dissolved in 50 g of methyl ethyl ketone was prepared. The total amount of monomers at the time of preparation was adjusted to 50 g. In addition, mol% of each monomer represents mol% with respect to the whole monomer amount, and 8 mol% was used for the initiator with respect to the total amount of the monomer and the initiator.

  On the other hand, 50 g of ethyl methyl ketone was added to a 500 ml three-necked flask equipped with a thermometer and a dropping funnel, and a nitrogen purge was performed for 30 minutes. Then, it heated so that it might become 80 degreeC, stirring the inside of a flask with a magnetic stirrer. Next, the monomer solution was dropped into the flask over 3 hours using a dropping funnel. After dropping, the mixture was aged for 3 hours, and then cooled to 30 ° C. or lower to obtain a polymer solution.

  Thereafter, the polymer solution was transferred to a 2 L separatory funnel, and then the polymer solution was uniformly diluted with 150 g of n-hexane, and 600 g of methanol was added and mixed. Next, 30 g of distilled water was added, and the mixture was stirred and allowed to stand for 30 minutes. Thereafter, the lower layer was collected to obtain a propylene glycol monomethyl ether acetate solution. For the polymer (A-1) in this propylene glycol monomethyl ether acetate solution, the yield (%), the residual low molecular weight (referred to as “low molecular weight component (%)” in Table 1), the weight average molecular weight (Table 1). Middle, indicated as “Mw”) and dispersity (indicated as “Mw / Mn” in Table 1).

  The polymer (A-1) obtained in this synthesis example has a yield of 67%, a residual low molecular weight of 0.1% or less, a weight average molecular weight of 6300, and a dispersity of 1.35. Met.

(Synthesis Examples 2 to 6)
Except having set it as the monomer and compounding quantity shown in Table 1, it carried out similarly to the synthesis example 1, and performed the synthesis examples 2-6, and obtained the polymer (A-2)-(A-6). Each of the obtained polymers (A-2) to (A-6) was subjected to the above various evaluations. The evaluation results are shown in Table 2.

(Synthesis Example 7)
43.08 g (50 mol%) of the compound (M-1) represented by the above formula (M-1), 56.92 g (50 mol%) of the compound (M-7) represented by the above formula (M-7). ) Was dissolved in 200 g of 2-butanone, and 4.21 g of 2,2′-azobisisobutyronitrile was further added to obtain a monomer solution.

  Meanwhile, a 500 ml three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution was added dropwise 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, and poured into 2000 g of methanol to precipitate a white powder. Thereafter, the precipitated white powder was filtered off. The filtered white powder was washed twice with 400 g of methanol as a slurry and filtered. Then, it dried at 50 degreeC for 17 hours, and obtained the polymer (B-1) of the white powder (70g, 70% of yield).

As for this polymer (B-1), Mw is 7600, Mw / Mn is 1.43, and as a result of ¹³ C-NMR analysis, the content of each repeating unit derived from the compound (M-1): compound (M- The content of each repeating unit derived from 7) was a copolymer of 46.0: 54.0 (mol%). In addition, content of the low molecular weight component derived from a compound (M-1) and a compound (M-7) was 0.03 mass% with respect to 100 mass% of polymers (B-1).

(Synthesis Example 8)
12.40 g (15 mol%) of the compound (M-6) represented by the above formula (M-6), 50.40 g (50 mol%) of the compound (M-7) represented by the above formula (M-7) ), And 37.20 g (35 mol%) of the compound (M-8) represented by the above formula (M-8) are dissolved in 200 g of 2-butanone, and 2,2′-azobisisobutyro is further dissolved. A monomer solution was obtained by adding 3.72 g of nitrile.

  Meanwhile, a 500 ml three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution was added dropwise 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, and poured into 2000 g of methanol to precipitate a white powder. Thereafter, the precipitated white powder was filtered off. The filtered white powder was washed twice with 400 g of methanol as a slurry. Then, it filtered and dried at 50 degreeC for 17 hours, and obtained the polymer (B-2) of the white powder (76 g, yield 76%).

As for this polymer (B-2), Mw is 6200, Mw / Mn = 1.52, As a result of ¹³ C-NMR analysis, the content of each repeating unit derived from the compound (M-6): compound (M- 7) Content of each repeating unit derived from 7): A copolymer having a content of the repeating unit derived from (M-8) of 14.3: 53.6: 32.1 (mol%). The content of the low molecular weight component derived from the compound (M-6), the compound (M-7), and the compound (M-8) is 0.02 mass relative to 100 mass% of the polymer (B-2). %Met.

Example 1
5 parts of polymer (A-1) as the first polymer (A), 95 parts of polymer (B-1) as the second polymer (B), triphenylsulfonium nonafluoro-n- as the acid generator 9.6 parts of butanesulfonate (referred to as “C-1” in Table 3), Nt-butoxycarbonyl-4-hydroxypiperidine (referred to as “D-1” in Table 3) as a nitrogen-containing compound 65 parts, 1400 parts of propylene glycol monomethyl ether acetate (referred to as “E-1” in Table 3), 30 parts of gamma-butyrolactone (referred to as “E-2” in Table 3) as a solvent, and cyclohexanone ( In Table 3, 600 parts) (mixed as “E-3”) were mixed to prepare a radiation sensitive resin composition. The following evaluation was performed about the prepared radiation sensitive resin composition.

(1) Measurement of elution amount:
Using CLEAN TRACK ACT8 (manufactured by Tokyo Electron Co., Ltd.), a silicon wafer having a resist film with a film thickness of 150 nm is formed by spin-coating the resist composition shown in Table 3 on a silicon wafer and baking (100 ° C., 60 seconds). did. A Teflon (registered trademark) ring having a diameter of 1 cm and a thickness of 1 mm was placed on this silicon wafer, and 1 mL of ultrapure water was filled therein 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. 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. When the elution amount was 2.0 × 10 ⁻¹² mol / cm ² / sec or more, it was ^judged as “bad”, and when it was less than 2.0 × 10 ⁻¹² mol / cm ² / sec, “good”. It was.

(2) Measurement of receding contact angle:
First, a film was formed on a substrate (wafer) with the radiation sensitive resin composition. Thereafter, the receding contact angle of the formed film was calculated in the following procedure using “DSA-10” manufactured by KRUS under an environment of room temperature 23 ° C., humidity 45%, and normal pressure.

  First, the wafer stage position is adjusted. Next, the wafer is set on the stage. Water is injected into the “DSA-10” needle. Next, the position of the needle is finely adjusted. Next, water is discharged from the needle to form a 25 μL water droplet on the wafer, and then the needle is once pulled out of the water droplet. Next, the needle is pulled down again to the finely adjusted position. Next, a water droplet is sucked with a needle at a speed of 10 μL / min for 90 seconds, and the contact angle is measured every second (total 90 times). Next, an average value is calculated for a total of 20 contact angles from the time when the contact angle is stabilized, and is set as the receding contact angle (°).

(3) Sensitivity:
First, a 12-inch silicon wafer having a 77 nm-thick lower layer antireflection film (“ARC29A”, manufactured by Brewer Science) on the surface was used as a substrate. For the formation of this antireflection film, “CLEAN TRACK ACT8” (manufactured by Tokyo Electron Ltd.) was used.

Next, the prepared radiation-sensitive resin composition was spin-coated on a substrate by “CLEAN TRACK ACT8” and pre-baked (PB) at 100 ° C. for 60 seconds to form a film having a thickness of 205 nm. This coating was exposed through a mask pattern using an ArF excimer laser exposure apparatus (“NSR S306C”, manufactured by Nikon, illumination conditions: NA 0.78 sigma 0.93 / 0.69). Thereafter, PEB was performed at 120 ° C. for 60 seconds. Thereafter, the resist film was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 30 seconds, washed with water, and dried to form a positive resist pattern. At this time, an exposure amount for forming a line-and-space pattern (1L1S) having a line width of 90 nm in a one-to-one line width is defined as an optimum exposure amount, and a value (mJ / cm ² ) of the optimum exposure amount is defined as sensitivity. . Note that a scanning electron microscope (“S-9380”, manufactured by Hitachi High-Technologies Corporation) was used for length measurement.

(4) Cross-sectional shape of pattern:
(3) The cross-sectional shape of the 90 nm line and space pattern formed in the sensitivity evaluation was observed with “S-4800” manufactured by Hitachi High-Technologies Corporation, and the intermediate portion of the line portion in the thickness direction of the film The line width Lb and the line width La on the coating surface were measured. After that, the formula: (La−Lb) / Lb is calculated, and the case where the calculated value is within the range of 0.9 ≦ (La−Lb) /Lb≦1.1 is determined as “good” and out of range Was determined as “bad”. In Table 4, “shape” is shown.

(5) Number of defects:
First, a film having a thickness of 120 nm was formed from a radiation-sensitive resin composition on a 12-inch silicon wafer on which a lower antireflection film was formed under the same conditions as in (3) sensitivity evaluation. Next, the coating film was rinsed with pure water for 90 seconds. Next, this coating film was passed through a mask pattern using an ArF excimer laser immersion exposure apparatus (“NSR S306C”, manufactured by NIKON) under the conditions of NA = 0.75, σ = 0.85, 1 / 2Annular. And exposed. After the exposure, rinsing was again performed with pure water for 90 seconds, and PEB was performed under the same conditions as in the above (3) sensitivity evaluation. Thereafter, the resist film was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 30 seconds, washed with water, and dried to form a positive resist pattern. At this time, the exposure amount for forming a hole pattern having a width of 1000 nm was determined as the optimum exposure amount. A hole pattern having a width of 1000 nm was formed on the entire surface of the wafer with this optimum exposure amount, and a defect inspection wafer was obtained. Note that a scanning electron microscope (“S-9380”, manufactured by Hitachi High-Technologies Corporation) was used for length measurement.

  Thereafter, the number of defects on the defect inspection wafer was measured using “KLA2351” manufactured by KLA-Tencor. Further, the defects measured by “KLA2351” were observed using a scanning electron microscope (“S-9380”, manufactured by Hitachi High-Technologies Corporation), and the defects determined to be resist-derived and the foreign matters derived from the outside Classified. After classification, when the total number of defects determined from resist (number of defects) was 100 / wafer or more, it was judged as “bad”, and when it was less than 100 / wafer, it was judged as “good”.

The radiation sensitive resin composition of this example has a good elution amount evaluation, a receding contact angle of 75 °, a sensitivity of 32 mJ / cm ² , a good shape, and an evaluation of the number of defects. It was good.

(Examples 2-5, Comparative Examples 1-3)
Except having used the component shown in Table 3 by the compounding quantity shown in Table 3, it carried out similarly to Example 1, and prepared the radiation sensitive resin composition of Examples 2-5 and Comparative Examples 1-3. Each evaluation mentioned above was performed about each prepared radiation sensitive resin composition. The evaluation results are shown in Table 4.

  As is clear from Table 4, the radiation sensitive resin compositions of Examples 1 to 5 can obtain a good pattern shape as compared with the radiation sensitive resin compositions of Comparative Examples 1 to 3, and water. It was confirmed that the resist film material can be hardly dissolved in the immersion exposure solution such as a resist film material which has a large receding contact angle with the immersion exposure solution and hardly causes development defects.

  The radiation-sensitive resin composition of the present invention can be used as a material capable of forming a resist film in lithography that will be further refined in the future. The resist pattern forming method of the present invention can be employed as a resist pattern forming method in lithography.

Claims (5)

A first polymer (A) having a repeating unit (1) represented by the following general formula (1) and a repeating unit (2) represented by the following general formula (2);
A second polymer (B) having an acid-dissociable functional group that dissociates by the action of an acid, the acid-dissociable functional group dissociating and becoming alkali-soluble,
A radiation sensitive resin composition comprising a radiation sensitive acid generator (C).

(In the general formula (1) and the general formula (2), R ¹ is independently of each other hydrogen, methyl group, or trifluoromethyl group. In the general formula (1), R ² is A straight-chain or branched hydrocarbon group having 1 to 10 carbon atoms, and R ³ is a single bond or a divalent organic group having 1 to 10 carbon atoms, wherein in the general formula (2), R ⁴ and R ⁵ is independently of each other a hydrogen atom, a linear or branched hydrocarbon group having 1 to 10 carbon atoms, or a monovalent C ⁴ to C 15 having a cyclic hydrocarbon having 3 to 10 carbon atoms. A hydrocarbon group, wherein at least one of R ⁴ and R ⁵ is the monovalent hydrocarbon group, and R ⁶ is a single bond or a divalent organic group having 1 to 10 carbon atoms.   The molar ratio of the repeating unit (1) to the repeating unit (2) in the first polymer (A) (the repeating unit (1) / the repeating unit (2)) is 20 / 80-80. The radiation sensitive resin composition according to claim 1, which is / 20.   The radiation sensitive resin composition according to claim 1 or 2, wherein the content of the first polymer (A) is 0.1 to 20 parts by mass with respect to 100 parts by mass of the second polymer (B). object.   The radiation sensitive resin composition according to any one of claims 1 to 3, wherein the acid dissociable functional group of the second polymer (B) is a group having a cyclic hydrocarbon in the structure thereof. (1) a step of forming a photoresist film on a substrate using the radiation-sensitive resin composition according to any one of claims 1 to 4;
(2) a step of disposing an immersion exposure liquid on the formed photoresist film, and subjecting the photoresist film to immersion exposure via the immersion exposure liquid;
(3) forming a resist pattern by developing the photoresist film that has been subjected to immersion exposure.