JP2011227463A - Radiation-sensitive resin composition and pattern formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition suitable for a liquid immersion exposure process in a resist pattern formation and for image development using an organic solvent.SOLUTION: A radiation-sensitive resin composition used in a resist pattern formation method in which image development is performed using an organic solvent (X) contains a polymer (A), a radiation-sensitive acid generator (B) and a solvent (C). The polymer (A) contains a specific acrylic-group repeating unit which has a lactone structure or a carbonate structure in a side chain.

Description

  The present invention relates to a radiation-sensitive resin composition and a method for forming an organic solvent development pattern using the same, and more specifically, subsequent exposure without performing prior post-exposure baking or development for multiple exposures. Radiation-sensitive resin composition used for continuous exposure methods, particularly patterning by double exposure, and suitable for use in an immersion exposure process using an immersion medium such as water, and the use thereof The present invention relates to a resist pattern forming method.

  In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, lithography technology capable of microfabrication at a level of 0.10 μm or less is required. In the future, finer pattern formation (for example, a fine resist pattern having a line width of about 45 nm) will be required. As means for achieving such fine pattern formation, it is conceivable to shorten the wavelength of the light source of the exposure apparatus (ArF excimer laser (wavelength: 193 nm)) or increase the numerical aperture (NA) of the lens. . However, in order to shorten the light source wavelength, a new expensive exposure apparatus is required. In addition, the increase in the numerical aperture (NA) of the lens has a problem that the depth of focus decreases even if the resolution is increased because the resolution and the depth of focus are in a trade-off relationship.

  Recently, a liquid immersion lithography (liquid immersion lithography) method has been reported as a lithography technique that can solve such problems. However, it is said that the progress of the exposure technique by the immersion exposure method is limited to 45 nm half pitch (hp), and technical development for the 32 nm hp generation that requires further fine processing is being carried out. In recent years, due to the demand for higher complexity and higher density of devices, 32 nm is obtained by superimposing sparse line patterns or isolated trench patterns shifted by a half cycle such as double patterning process (DP) or double exposure process (DE). A technique for patterning line and space (LS) has been proposed (see Non-Patent Document 1). The DE performs patterning by exposing at least two times to one resist coating layer.

  Specifically, as an example of patterning a 40 nm contact hole (CH), a positive resist composition is used, for example, a first LS pattern of 40 nm is exposed, and the LS pattern is orthogonal to the first LS. Thus, a fine contact hole of 40 nm can be formed by performing the second exposure process.

  Furthermore, a development process using an acid organic solvent as a developer has also been proposed (see Patent Document 1). The development process using an organic solvent refers to a process in which an unexposed portion is dissolved in an organic solvent and the exposed portion is hardly soluble to form a pattern.

Japanese Patent No. 3869306

SPIE 2006 Vol. 6153 6153K

  However, although there are some proposed processes, there has not yet been proposed a specific material that can be suitably used for patterning using such an immersion exposure process and developing with an organic solvent. Is the current situation.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is that it is used for patterning in which development is performed with an organic solvent, and is also suitably used for an immersion exposure process. It is in providing the radiation sensitive resin composition which can be performed.

（式（１−１）〜（１−７）において、Ｒ^１は水素原子、メチル基、またはトリフルオロメチル基である。Ｒ^２は水素原子または炭素数１〜４の置換もしくは非置換のアルキル基である。Ｒ^３は水素原子またはメトキシ基である。Ａは単結合、メチレン基、炭素数２〜１０の直鎖状もしくは分岐状の２価の炭化水素基、または酸素原子もしくは硫黄原子を有する２価の連結基である。Ｂは酸素原子またはメチレン基である。Ｒ^４は単結合または２価の連結基である。Ｒ^５は環状カーボネート構造を有する１価の有機基である。ｐは２〜３の整数であり、ｍは０または１であり、ｎは０または１である。但し、ｎが０のとき、Ａが単結合、かつＢがメチレン基であることはない。） As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be achieved by adding predetermined constituents to the resin component, and the present invention has been completed. It was.
That is, the present invention is a radiation sensitive resin composition used in a resist pattern forming method in which development is performed with an organic solvent (X), and the polymer (A), the radiation sensitive acid generator (B), A solvent (C), and the polymer (A) includes at least one repeating unit (a2) selected from the following formula (1-1) to the following formula (1-7). It is a radiation sensitive resin composition.

(In the formulas (1-1) to (1-7), R ¹ is a hydrogen atom, a methyl group, or a trifluoromethyl group. R ² is a hydrogen atom or a substituted or unsubstituted alkyl having 1 to 4 carbon atoms. R ³ represents a hydrogen atom or a methoxy group, A represents a single bond, a methylene group, a linear or branched divalent hydrocarbon group having 2 to 10 carbon atoms, an oxygen atom or a sulfur atom. B is an oxygen atom or a methylene group, R ⁴ is a single bond or a divalent linking group, R ⁵ is a monovalent organic group having a cyclic carbonate structure, p Is an integer of 2 to 3, m is 0 or 1, and n is 0 or 1. However, when n is 0, A is not a single bond and B is not a methylene group.

（式（２−１）〜（２−４）において、Ｒ^６は水素原子、トリフルオロメチル基、または炭素数１〜３のアルキル基である。Ｒ^７はそれぞれ独立に、水素原子または水酸基である。Ｒ^８は炭素数１〜５の直鎖状もしくは分岐状のヒドロキシアルキル基である。Ｌは炭素数１〜５のアルキル基で置換されていてもよい炭素数１〜５の直鎖状もしくは分岐状の２価の炭化水素基である。Ｍは下記式（Ｍ１）ないし式（Ｍ４）のいずれかで示される基である。ｑは１〜３の整数である。）

It is preferable that the polymer (A) further includes at least one repeating unit (a3) selected from the following formulas (2-1) to (2-4).

(In Formulas (2-1) to (2-4), R ⁶ is a hydrogen atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ⁷ is independently a hydrogen atom or a hydroxyl group. R ⁸ is a linear or branched hydroxyalkyl group having 1 to 5 carbon atoms, and L is a linear chain having 1 to 5 carbon atoms that may be substituted with an alkyl group having 1 to 5 carbon atoms. Alternatively, it is a branched divalent hydrocarbon group, M is a group represented by any of the following formulas (M1) to (M4), and q is an integer of 1 to 3.)

（式（３）において、Ｒ^１は水素原子、メチル基またはトリフルオロメチル基である。Ｒ^９は、相互に独立に、炭素数１〜４の直鎖状も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もしくはその誘導体である。但し、いずれか２つのＲ^９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いてもよい。） It is preferable that the polymer (A) further includes a repeating unit (a1) represented by the following formula (3).

(In Formula (3), R ¹ is a hydrogen atom, a methyl group, or a trifluoromethyl group. R ⁹ is independently a linear or branched alkyl group having 1 to 4 carbon atoms, or a carbon atom. a monovalent alicyclic hydrocarbon group or a derivative thereof having 4 to 20. However, divalent alicyclic any two R ⁹ are bonded to each other having 4 to 20 carbon atoms hydrocarbon group or A derivative thereof may be formed.)

The present invention includes a resist layer forming step of forming a resist layer by applying a radiation sensitive resin composition on a substrate, an exposure step of irradiating the resist layer through a photomask, and an organic solvent (X). In the resist pattern forming method comprising the development step of developing with the above, the radiation sensitive resin composition includes a resist pattern forming method which is the radiation sensitive resin composition.
Moreover, in the said exposure process, it is preferable to perform exposure continuously after exposure.
The organic solvent (X) is preferably at least one solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents.
In the exposure step, the first exposure and the second exposure using a photomask for forming a line and space pattern are performed, and the first exposure pattern and the second exposure pattern intersect each other. preferable.

In the pattern forming method using the radiation-sensitive resin composition of the present invention, the polarity of an exposed portion where an acid is generated is changed by exposure, and thus, it is possible to make it slightly soluble in an organic solvent (X). As a result, patterning can be performed easily and reliably by organic solvent development.
Here, the polarity change means that the polarity changes before and after the acid-dissociable group is eliminated by the elimination of the acid-dissociable group in the polymer (A) as a resin component.

  According to the radiation-sensitive resin composition of the present invention and the resist pattern forming method using the same, the resist layer is subjected to exposure treatment a plurality of times without using a second resist composition such as DP in patterning by DE. By doing so, a contact hole pattern can be formed, which is superior to DP in terms of alignment accuracy and throughput. Moreover, it can employ | adopt suitably also for an immersion exposure process.

In the process of the resist pattern formation method concerning this invention, it is a schematic diagram which shows an example of the state after forming a resist layer on a board | substrate with sectional drawing. In the process of the resist pattern formation method which concerns on this invention, it is a schematic diagram which shows an example of the state which performs a 1st exposure to a resist layer from the upper part. In the process of the resist pattern formation method which concerns on this invention, it is a schematic diagram which shows an example of the state which performs a 2nd exposure to a resist layer from the upper part.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. The scope of the present invention includes those in which the following embodiments are appropriately modified and improved without departing from the spirit of the present invention based on the ordinary knowledge of those skilled in the art.

<Resist pattern formation method>
An embodiment of a resist pattern forming method of the present invention will be described with reference to the drawings. In the present specification, the “line pattern” means that the resist pattern is an LS having a line portion and a space portion.

(1) Resist Layer Formation Step on Substrate FIG. 1 is a schematic diagram showing an example of a state after forming a resist layer 2 on a substrate 1 in a cross-sectional view.
The substrate 1 is not particularly limited, and for example, a conventionally known substrate such as a silicon wafer or a wafer coated with aluminum can be used. 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 Application Laid-Open No. 59-93448, etc. An organic or inorganic antireflection film can also be formed thereon.

The resist layer 2 can be formed by applying a radiation sensitive resin composition on a substrate. The radiation sensitive resin composition is a radiation sensitive resin composition of the present invention described later. The coating method is not particularly limited, and can be performed by appropriate coating means such as spin coating, cast coating, roll coating and the like. In addition, although the thickness of the resist layer 2 to be formed is not particularly limited, it is usually 10 to 1000 nm and preferably 10 to 500 nm.
Moreover, after apply | coating a radiation sensitive resin composition, you may volatilize the solvent in a coating film by prebaking (henceforth "PB") as needed. The heating conditions for PB are appropriately selected depending on the composition of the radiation sensitive resin composition 3, but are usually about 30 to 200 ° C. and preferably 50 to 150 ° C.
Further, in order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film can be provided on the resist layer as disclosed in, for example, JP-A-5-188598. In order to prevent the acid generator and the like from flowing out of the resist layer, a liquid immersion protective film can be provided on the resist layer as disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-352384. . These techniques can be used in combination.

(2) Exposure process As shown in FIG. 2, after forming the resist layer 2 on the substrate 1 using the radiation-sensitive resin composition, a desired region is passed through a mask having a predetermined LS pattern, and water, etc. The exposure is performed on the exposure unit 3 from above the plan view through the immersion liquid.
Further, as shown in FIG. 3, the second exposure unit 4 is exposed from above the plan view so as to intersect the first exposure unit 3. It is preferable that the first exposure unit 3 and the second exposure unit 4 are orthogonal to each other. By being orthogonal, it becomes easy to form a perfect circular contact hole pattern in the unexposed portion 5 surrounded by the exposed portion 3 and the exposed portion 4. Further, the contact hole may be formed by one exposure by using a dot pattern mask. In the exposure, an immersion liquid such as water or a fluorine-based inert liquid may be optionally passed.
Depending on the type of radiation-sensitive acid generator (B) contained in the radiation-sensitive resin composition (hereinafter also referred to as “acid generator (B)”), It is appropriately selected from deep ultraviolet rays, X-rays, charged particle beams and the like. Among these, far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable, and far ultraviolet rays by ArF excimer laser (wavelength 193 nm) are particularly preferable.
The exposure conditions such as the exposure amount are appropriately selected according to the blending composition of the radiation-sensitive resin composition, the type of additive, and the like.
In addition, baking (hereinafter, also referred to as “PEB”) that is heat treatment is preferably performed after exposure. By performing PEB, the dissociation reaction of the acid-dissociable group or acid-labile group in the radiation-sensitive resin composition can proceed smoothly. Although the temperature conditions of PEB are suitably selected by the composition of a radiation sensitive resin composition, they are 30-200 degreeC normally, and it is preferable that it is 50-170 degreeC.

(3) Development Step After the exposure step, development using an organic solvent (X) is performed to form a contact hole pattern on the substrate.
Preferable examples of the organic solvent (X) include polar solvents such as ketone solvents, ester solvents, alcohol solvents, ether solvents, amide solvents, and hydrocarbon solvents.
Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, and methyl isobutyl ketone. Can be mentioned.
Examples of ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl-3-ethoxy. Examples include propionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, and propyl lactate.
Examples of alcohol solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol; ethylene glycol And glycol solvents such as triethylene glycol, and glycol ether solvents such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol, propylene glycol, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and methoxymethylbutanol. be able to.
Examples of the ether solvent include dioxane, tetrahydrofuran and the like in addition to the glycol ether solvent.
Examples of the amide solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and the like.
Examples of the hydrocarbon solvent include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as pentane, hexane, octane and decane.

  Among these organic solvents (X), butyl acetate, isopropyl acetate, amyl acetate, and methyl amyl ketone are preferable. A plurality of the above organic solvents (X) may be mixed, or may be used by mixing with a solvent other than the above or water.

(4) Rinsing step In the rinsing step after development, a rinsing solution containing at least one organic solvent selected from alkane solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents and ether solvents. It is preferable to wash using More preferably, after the development, a step of washing with a rinsing solution containing at least one organic solvent selected from a ketone solvent, an ester solvent, an alcohol solvent, and an amide solvent is performed. Even more preferably, after the negative development, a step of washing with a rinsing solution containing an alcohol solvent or an ester solvent is performed. Particularly preferably, after the negative development, a step of washing with a rinsing solution containing a monohydric alcohol having 6 to 8 carbon atoms is performed. Here, examples of the monohydric alcohol having 6 to 8 carbon atoms used in the rinsing step after the negative development include linear, branched, and cyclic monohydric alcohols, specifically, 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol, and the like can be used. Hexanol, 2-hexanol, and 2-heptanol.

  A plurality of the components of the rinse liquid may be mixed, or may be used by mixing with an organic solvent other than the above. The water content in the rinsing liquid is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. By setting the water content to 10% by mass or less, good development characteristics can be obtained. An appropriate amount of a surfactant can be further added to the rinse solution.

  The resist pattern forming method of the present invention is preferably formed so that the line portions of the resist pattern intersect each other as shown in FIG. A contact hole pattern can be formed on the substrate by development using an organic solvent (X) at portions that intersect each other.

<Radiation sensitive resin composition>
In the radiation-sensitive resin composition, an acid-dissociable group or an acid-labile group existing in the composition is dissociated by the action of an acid generated from a radiation-sensitive acid generator by exposure to generate a carboxyl group. The exposed portion is less soluble in the organic solvent (X), and the unexposed portion is dissolved and removed by the organic solvent (X) to form a pattern. It is particularly suitable for forming a contact hole pattern. Hereinafter, the radiation sensitive resin composition of this invention is demonstrated.

The radiation sensitive resin composition contains a polymer (A) containing a repeating unit having an acid labile group, an acid generator (B), and a solvent (C).
In addition, the “acid labile group” and the “acid dissociable group” in the present specification refer to a group dissociated by an acid, and do not refer to a particularly different group. A polymer having an acid labile group or an acid dissociable group and soluble in an organic solvent (X) is converted into a carboxyl group by dissociation of the acid labile group or acid dissociable group by the action of an acid. The polymer is insoluble or hardly soluble in the organic solvent (X).

<Polymer (A)>
The polymer (A) contains at least one repeating unit (a2) selected from the above formula (1-1) to the following formula (1-7).
(I) Repeating unit (a2)
The repeating unit (a2) is obtained by polymerizing the monomers represented by the following formula (1a-1) to the following formula (1a-7), respectively.

（式（１ａ−１）〜式（１ａ−７）において、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ａ、Ｂ、ｐ、ｍ、ｎは、式（１−１）〜式（１−７）におけるそれらと同義である。）

In (formula (1a-1) to Formula ^{(1a-7), R 1} , R 2, R 3, R 4, R 5, A, B, p, m, n in Formula (1-1) to Formula (It is synonymous with those in (1-7).)

Examples of the substituted or unsubstituted alkyl group having 1 to 4 carbon atoms represented by R ² in the above formula (1-1) include a methyl group, an ethyl group, a propyl group, a butyl group, and structural isomers thereof. It is done.

  Examples of the divalent linking group having an oxygen atom or sulfur atom represented by A in the above formulas (1-2) and (1-3) include -Ra-O-Rb- and -Ra-CO-Rb-. , -Ra-COO-Rb-, or -Ra-S-Rb-, and the like. Ra and Rb each independently represent a single bond or a hydrocarbon group having 1 to 10 carbon atoms. Examples of the divalent linking group include groups represented by the following formulas (A-1) to (A-6).

In the above formulas (A-1) to (A-6), R ^a1 and R ^b1 each independently represent a hydrogen atom, a methyl group, an ethyl group, or a propyl group. Q and r each independently represent an integer of 0 to 5. However, q and r are not 0 simultaneously in one linking group.

Examples of the divalent linking group represented by R ⁴ in the above formula (1-7) include a hydrocarbon group having 1 to 10 carbon atoms, —Rc—O—Rd—, —Rc—CO—Rd—, and —Rc. And a divalent group represented by —COO—Rd—. Rc and Rd each independently represent a hydrocarbon group having 1 to 10 carbon atoms. Rc and Rd may be bonded to either the oxygen atom on the main chain side or R ⁵ .

Examples of R ⁵ in the above formula (1-7) include groups represented by the following formulas (1-7a) and (1-7b).

（式（１−７ａ）において、ｎ_１は０〜２の整数を表す。式（１−７ｂ）において、ｎ_２〜ｎ_５は、それぞれ独立に、０〜２の整数を表す。式（１−７ａ）および式（１−７ｂ）において、「＊」は式（１−７）におけるＲ^４に結合する結合手を示す。また、式（１−７ａ）および式（１−７ｂ）で表される基は置換基を有していてもよい。）

(In Formula (1-7a), n ₁ represents an integer of 0 to 2. In Formula (1-7b), n _{2 to} n ₅ each independently represents an integer of 0 to 2. Formula (1 −7a) and formula (1-7b), “*” represents a bond bonded to R ⁴ in formula (1-7), and is represented by formula (1-7a) and formula (1-7b). The group to be substituted may have a substituent.)

  Preferable groups represented by the above formula (1-7a) or formula (1-7b) include those represented by the following formula (1-7aa) or (1-7bb).

（式（１−７ａａ）および式（１−７ｂｂ）において、「＊」は、一般式（１−７）におけるＲ^４に結合する結合手を表す。）

(In formulas (1-7aa) and (1-7bb), “*” represents a bond bonded to R ⁴ in formula (1-7).)

Specific examples of the repeating unit (1-7) include those represented by the following formula. Incidentally, ^{R 1} in the formula (1-7-1) - (1-7-22) has the same meaning as ^{R 1} in the formula (1-7).

  Monomers that give repeating units represented by the formula (1-7) are described in, for example, Tetrahedron Letters, Vol. 27, no. 32 p. 3741 (1986), Organic Letters, Vol. 4, no. 15 p. 2561 (2002), etc., and can be synthesized by a conventionally known method.

  Preferred monomers for giving the repeating unit (a2) are exemplified below.

  A polymer (A) may contain only 1 type of repeating units (a2), and may contain 2 or more types. The content ratio of the repeating unit (a2) is usually 80 mol% or less, preferably 20 to 80 mol%, and more preferably 30 to 100 mol% of the total repeating units contained in the polymer (A). 70 mol%. When the content ratio of the repeating unit (a2) is within this range, it is particularly effective from the viewpoint of the effect of suppressing the occurrence of scum after photolithography and the effect of suppressing the significant pattern top loss.

(Ii) Repeating unit (a3)
The polymer (A) preferably contains at least one repeating unit (a3) selected from the above formulas (2-1) to (2-4). A polymer (A) can improve the etching tolerance of an exposure part by containing a repeating unit (a3).

Examples of the alkyl group having 1 to 3 carbon atoms represented by R ⁶ in the above formulas (2-1) to (2-4) include a methyl group, an ethyl group, and a propyl group.
In addition, examples of the linear or branched hydroxyalkyl group having 1 to 5 carbon atoms represented by R ⁸ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or hydrogen of these structural isomers. Examples include groups in which an atom is substituted with a hydroxyl group.
Moreover, as a C1-C5 linear or branched hydrocarbon group which may be substituted by the C1-C5 alkyl group represented as L, a methylene group, ethylene group, propylene group, And a butylene group.
M represents a group represented by any of the above formulas (M1) to (M4). Moreover, the direction of the coupling | bonding of said Formula (M1) and Formula (M2) is not ask | required. For example, in the formula (M1), the oxygen atom may be bonded to the bridge head position of adamantane or may be bonded to —CH 2 —.
q represents an integer of 1 to 3, and q = 1 is particularly preferable.

  Examples of the polymerizable monomer that gives the repeating unit (a3) include compounds represented by the following formulas (2-a) to (2-t). In the present invention, the polymerizable monomer that gives the repeating unit (a3) is not limited thereto.

  A polymer (A) may contain only 1 type of repeating units (a3), and may contain 2 or more types. The content ratio of the repeating unit (a3) is usually 60 mol% or less, preferably 60 to 5 mol%, more preferably 50 to 50 mol% based on 100 mol% of the total repeating units contained in the polymer (A). 5 mol%. When the content ratio of the repeating unit (a3) is within this range, the etching resistance of the exposed portion is improved.

(Iii) Repeating unit (a1)
It is preferable that a polymer (A) contains the repeating unit (a1) containing the acid labile group represented by the said Formula (3).
Examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ⁹ in the above formula (3) 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.
Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or derivatives thereof include cyclohexane such as norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane. Groups composed of alicyclic rings derived from alkanes and the like; groups composed of these alicyclic rings are, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2- And a group substituted with a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms such as methylpropyl group, 1-methylpropyl group and t-butyl group.
Furthermore, as the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms formed by bonding any two R ⁹ to each other or a derivative thereof, norbornane, tricyclodecane, tetracyclododecane, adamantane, A group consisting of an alicyclic ring derived from cyclopentane, cyclohexane, etc .; a group consisting of these alicyclic rings is, for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, Substituted with a linear or branched alkyl group having 1 to 4 carbon atoms such as 2-methylpropyl group, 1-methylpropyl group or t-butyl group, or an alicyclic hydrocarbon group having 3 to 10 carbon atoms Groups and the like.

In the formula (3), preferable examples of the group represented by —C (R ⁹ ) ₃ include t-butyl group, 1-n- (1-ethyl-1-methyl) propyl group, 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 Groups having no alicyclic ring such as -n- (1,1-diethyl) butyl group and 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 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) tetracyclododecanyl group, 2- (2-ethyl) tetracyclododecanyl group, 2- (2-n-propyl) tetracyclododecanyl group, 2- ( 2-i-propyl) tetracyclododecanyl group, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 2-propyl-2-adamantyl group and other groups having an alicyclic ring; Fat A group having an aromatic ring, for example, a carbon number 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; And a group substituted with a cyclic alkyl group having 4 to 20 carbon atoms such as a linear or branched alkyl group having 1 to 10 carbon atoms, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

  Among the monomers that give the repeating unit (a1), (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, 1-ethyl-1-cyclopentyl ester of (meth) acrylic acid, 1-methyl-1-cyclohexyl ester of (meth) acrylic acid, (meth ) Acrylic acid ethyl-1-cyclohexyl ester, and the like are particularly preferable.

  Preferred monomers for giving the repeating unit (a1) are exemplified below.

  A polymer (A) may contain only 1 type of repeating units (a1), and may contain 2 or more types. The content ratio of the repeating unit (a1) is preferably 20 to 90 mol%, more preferably 20 to 80 mol%, still more preferably with respect to 100 mol% of the total repeating units contained in the polymer (A). 20-70 mol%. When the content ratio of the repeating unit (a1) is within this range, it is particularly effective from the viewpoint of achieving both water repellency after coating and an increase in contact angle with the developer after PEB.

(IV) Other Repeating Units The polymer (A) is one type of repeating unit other than the repeating unit (a1), the repeating unit (a2) and the repeating unit (a3) (hereinafter also referred to as “other repeating unit”). The above may be included.
Examples of other repeating units include a repeating unit represented by the formula (4) (hereinafter also referred to as “repeating unit (a4)”) and a repeating unit represented by the formula (5) (hereinafter referred to as “repeating unit ( a5) "), the repeating unit (b-2-1) represented by the formula (b-2-1), and the repeating unit (b-2-2) represented by the formula (b-2-2). And other repeating units (a6).

（式（４）において、Ｒ^１０は、水素原子、メチル基またはトリフルオロメチル基である。Ｙは、単結合または炭素数１〜３の２価の有機基である。Ｗは、炭素数７〜２０の置換または非置換の多環型脂環式炭化水素基である。但し、上記多環型脂環式炭化水素基が置換基を有する場合、置換基は炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、炭素数４〜２０の環状のアルキル基、ヒドロキシル基、シアノ基、炭素数１〜１０のヒドロキシアルキル基、カルボキシル基、またはオキソ基である。）

(In Formula (4), R ¹⁰ is a hydrogen atom, a methyl group, or a trifluoromethyl group. Y is a single bond or a divalent organic group having 1 to 3 carbon atoms. W is 7 carbon atoms. A substituted or unsubstituted polycyclic alicyclic hydrocarbon group of -20, provided that when the polycyclic alicyclic hydrocarbon group has a substituent, the substituent is a straight chain having 1 to 10 carbon atoms. Or a branched alkyl group, a cyclic alkyl group having 4 to 20 carbon atoms, a hydroxyl group, a cyano group, a hydroxyalkyl group having 1 to 10 carbon atoms, a carboxyl group, or an oxo group.)

（式（５）において、Ｒ^１１は、水素原子、炭素数１〜４のアルキル基、トリフルオロメチル基またはヒドロキシメチル基である。Ｒ^１２は、２価の有機基である。）

(In Formula (5), R ¹¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a trifluoromethyl group, or a hydroxymethyl group. R ¹² is a divalent organic group.)

In the formula (4), examples of the substituted or unsubstituted polycyclic alicyclic hydrocarbon group having 7 to 20 carbon atoms represented as W include bicyclo [2.2.1] heptane represented by the following formula: (4a), bicyclo [2.2.2] octane (4b), tricyclo [5.2.1.0 ^2,6 ] decane (4c), tetracyclo [6.2.1.1 ^3,6 . Hydrocarbon groups derived from cycloalkanes such as 0 ^2,7 ] dodecane (4d) and tricyclo [3.3.1.1 ^3,7 ] decane (4e).

  When the hydrocarbon group derived from the cycloalkane has a substituent, examples of the substituent include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, 2- C1-C10 linear or branched alkyl groups such as methylpropyl group, 1-methylpropyl group and t-butyl group, cyclic groups having 4 to 20 carbon atoms such as cyclopentyl group, cyclohexyl group and cyclooctyl group And the like. In addition, a substituent is not limited to these alkyl groups, A hydroxyl group, a cyano group, a C1-C10 hydroxyalkyl group, a carboxyl group, and an oxo group may be sufficient.

In the formula (5), examples of the alkyl group having 1 to 4 carbon atoms represented by R ¹¹ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and 2-methylpropyl. Group, 1-methylpropyl group, t-butyl group and the like.

In the formula (5), the divalent organic group represented by R ¹² is preferably a divalent hydrocarbon group. It may be an alkylene glycol group, an alkylene ester group or the like. Specific examples of the divalent organic group include propylene groups such as methylene group, ethylene group, 1,3-propylene group, and 1,2-propylene group, tetramethylene group, pentamethylene group, hexamethylene group, and heptamethylene. Group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group , Nonadecamethylene group, icosalen group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4- Chains such as butylene group, 2-methyl-1,4-butylene group, ethylidene group, propylidene group, 2-propylidene group Hydrocarbon group; cyclobutylene group such as 1,3-cyclobutylene group; cyclopentylene group such as 1,3-cyclopentylene group; cyclohexylene group such as 1,4-cyclohexylene group; A monocyclic hydrocarbon ring group such as a cycloalkylene group having 3 to 10 carbon atoms such as a cyclooctylene group such as an octylene group; a norbornylene group such as a 1,4-norbornylene group or a 2,5-norbornylene group; Examples thereof include a bridged cyclic hydrocarbon ring group such as a 2- to 4-cyclic hydrocarbon ring group having 4 to 30 carbon atoms such as an adamantylene group such as a 5-adamantylene group or a 2,6-adamantylene group. it can. Among these, a hydrocarbon group containing a 2,5-norbornylene group, a 1,2-ethylene group, and a propylene group are preferable.

When R ¹² contains a divalent aliphatic cyclic hydrocarbon ring group, a bistrifluoromethyl-hydroxy-methyl group (—C (CF ₃ ) ₂ OH) and a divalent aliphatic cyclic carbonization group It is preferable to arrange an alkylene group having 1 to 4 carbon atoms as a spacer between the hydrogen group.

  As the repeating unit (a6), a carboxyl group-containing ester having a bridged hydrocarbon skeleton of an unsaturated carboxylic acid; a (meth) acrylic acid ester having no bridged hydrocarbon skeleton; an unsaturated carboxylic acid Carboxyl group-containing esters that do not have a bridged hydrocarbon skeleton; polyfunctional monomers that have a bridged hydrocarbon skeleton; polymerization of polyfunctional monomers that do not have a bridged hydrocarbon skeleton There are units in which the unsaturated bond is cleaved. Among these, a repeating unit in which a polymerizable unsaturated bond of (meth) acrylic acid ester having a bridged hydrocarbon skeleton is cleaved is preferable. The polymer (A) may contain only one type of repeating units (a4) to (a6), (b-2-1) or (b-2-2), and contains two or more types. It may be a thing.

  Preferred examples of the monomer giving the other repeating unit are shown below.

[Method for Preparing Polymer (A)]
For the polymer (A), for example, the polymerizable unsaturated monomer that gives each repeating unit described above is used with a radical polymerization initiator such as a hydroperoxide, a dialkyl peroxide, a diacyl peroxide, or an azo compound. If necessary, it can be prepared by polymerization in an appropriate solvent in the presence of a chain transfer agent.
Examples of the solvent used for polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, norbornane. Cycloalkanes such as benzene, toluene, xylene, ethylbenzene, cumene and other aromatic hydrocarbons; chlorobutane, bromohexane, dichloroethane, hexamethylene dibromide, chlorobenzene and other halogenated hydrocarbons; ethyl acetate, acetic acid n- Saturated carboxylic acid esters such as butyl, i-butyl acetate and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone and 2-heptanone; tetrahydrofuran, dimethoxyethane, diethoxyethane and the like There are ethers. In addition, these solvents may be used individually by 1 type, and 2 or more types may be mixed and used for them.

[Physical properties of polymer (A)]
The weight average molecular weight (hereinafter also referred to as “Mw”) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer (A) is not particularly limited, but is 1,000 to 100,000, respectively. It is preferably 1,000 to 30,000, more preferably 1,000 to 20,000. If the Mw is less than 1,000, the heat resistance of the resist layer may be reduced. On the other hand, if it exceeds 100,000, the developability of the alkali developing portion may be lowered.
In addition, the ratio (Mw / Mn) between the Mw of each polymer and the polystyrene-equivalent number average molecular weight (hereinafter also referred to as “Mn”) by gel permeation chromatography (GPC) of each polymer is usually: It is 1-5, and it is preferable that it is 1-3.

The polymer (A) may contain a low molecular weight component derived from a monomer used for preparation. The content of this low molecular weight component is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, and still more preferably 100% by mass (in terms of solid content) of each polymer. It is 0.05 mass% or less. When the content ratio of the low molecular weight component is 0.1% by mass or less, it is possible to reduce the amount of the eluate in the immersion liquid such as water that is in contact during the immersion exposure. In addition, foreign matters are less likely to occur in the resist during resist storage, and coating unevenness is less likely to occur during resist application, so that the occurrence of defects during resist pattern formation can be sufficiently suppressed.
In the present specification, the “low molecular weight component” means a component having an Mw of 500 or less, and specifically includes a monomer, a dimer, a trimer, and an oligomer. The low molecular weight component can be removed by, for example, chemical purification methods such as washing with water and liquid-liquid extraction, or a combination of these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation. The analysis can be performed by high performance liquid chromatography (HPLC).

Furthermore, it is preferable that the polymer (A) has few impurities such as halogen and metal. This is because the sensitivity, resolution, process stability, pattern shape, and the like of the resist layer to be formed can be further improved by reducing the impurities.
Examples of the purification method of the polymer (A) include chemical purification methods such as washing with water and liquid-liquid extraction, and combinations of these chemical purification methods with physical purification methods such as ultrafiltration and centrifugation. is there.

<Acid generator (B)>
Examples of the acid generator (B) include onium salt compounds, halogen-containing compounds, diazoketone compounds, sulfone compounds, and sulfonic acid compounds.
The acid generator (B) is preferably a compound represented by the following formula (6).

In the above formula (6), R ¹³ 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 ¹⁴ 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. Represents a cyclic or cyclic alkanesulfonyl group. Furthermore, R ¹⁵ are independently of each other, represent a linear or branched alkyl group, a phenyl group or a naphthyl group, having 1 to 10 carbon atoms. Two R ¹⁵ may be bonded to each other to form a C 2-10 divalent group containing a sulfur cation. However, the phenyl group, naphthyl group, and divalent group having 2 to 10 carbon atoms may have a substituent. k represents an integer of 0 to 2, and r represents an integer of 0 to 10 (preferably an integer of 0 to 2). X ⁻ represents an anion represented by the following formulas (7-1) to (7-4).

In the formulas (7-1) and (7-2), R ¹⁶ represents a fluorine atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms. In Formula (7-1), t represents an integer of 1 to 10. In formulas (7-3) and (7-4), R ¹⁷ independently represents a linear or branched alkyl group having 1 to 10 carbon atoms substituted with a fluorine atom. Moreover, two R < ¹⁷ > may couple | bond together and may form the C2-C10 bivalent organic group substituted by the fluorine atom. However, the C2-C10 divalent organic group substituted with a fluorine atom may have a substituent other than a fluorine atom.

  The acid generator (B) may contain the acid generator represented by the above formula (6) or the above-exemplified acid generator alone, or may contain two or more kinds.

The usage-amount of an acid generator (B) is 20 mass% or less with respect to 100 mass% of radiation sensitive resin compositions, Preferably it is 1-15 mass%.
Moreover, when using another acid generator, the use ratio is 80 mass% or less normally with respect to 100 mass% of acid generators (B), Preferably it is 60 mass% or less.

<Solvent (C)>
Examples of the solvent (C) include 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-methyl-2-pentanone, and 3,3-dimethyl. Linear or branched ketones such as 2-butanone, 2-heptanone, 2-octanone; cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, isophorone Cyclic ketones such as 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 Propylene glycol monoalkyl ether acetates such as acetate, propylene glycol mono-i-butyl ether acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol mono-t-butyl ether acetate; methyl 2-hydroxypropionate, 2-hydroxypropionic acid Ethyl, 2-hydroxypropionate n-propyl, 2-hydroxypropionate i-propyl, 2-hydroxypropionate n-butyl, 2-hydroxypropionate i-butyl, 2-hydroxypropionate sec-butyl, 2-hydroxy Alkyl 2-hydroxypropionates such as t-butyl propionate; methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionate Methyl propionic acid, other 3-alkoxy propionic acid alkyl such as ethyl 3-ethoxypropionate,

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

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

The radiation sensitive resin composition may contain 1 type of solvent (C) individually, and may contain 2 or more types.
The amount of the solvent (C) used is such that the total solid concentration of the radiation-sensitive resin composition is usually 1 to 50% by mass, and preferably 1 to 25% by mass.

<Additives>
The radiation-sensitive resin composition is, if necessary, an acid diffusion controller (D), an alicyclic additive, a surfactant, a sensitizer, a fluorine atom-containing polymer (hereinafter also referred to as polymer (F). ) And other various additives.
(I) Acid diffusion controller (D):
The acid diffusion control agent is a component having an action of controlling a diffusion phenomenon of an acid generated from the acid generator (B) by exposure in the resist layer and suppressing an undesirable chemical reaction in a non-exposed region. By containing such an acid diffusion controller, the storage stability of the radiation sensitive resin composition is improved. In addition, the resolution as a resist is further improved, and it is possible to suppress changes in the line width of the resist pattern due to fluctuations in the holding time (PED) from exposure to post-exposure heat treatment, and an extremely excellent process stability. A thing is obtained.

Examples of the acid diffusion controller include an amine compound, an amide group-containing compound, a urea compound, and a nitrogen-containing heterocyclic compound.
(Amine compound)
Mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylanilines or derivatives thereof; 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 (1- (4-aminophenyl) ) -1-methylethyl) benzene, 1,3-bis (1- (4-aminophenyl) -1-methylethyl) benzene, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ′, N ″ , N ″ -pentamethyldiethylenetriamine and the like.

(Amido group-containing compound)
Preferred examples of the amide group-containing compound include Nt-butoxycarbonyl group-containing amino compounds such as Nt-butoxycarbonylpyrrolidine, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N- Examples include methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, and isocyanuric acid tris (2-hydroxyethyl).

(Urea compound)
Preferred examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butyl. There is thiourea.
(Nitrogen-containing heterocyclic compounds)
Preferable examples of the nitrogen-containing heterocyclic compound include imidazoles; pyridines; piperazines, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidineethanol, 3-piperidino-1,2-propanediol, Morpholine, 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2 2.2.2] Octane and the like.

  Further, as the acid diffusion control agent, in addition to the above-described acid diffusion control agent, a photodegradable base that is exposed to light and generates a base can be used. As an example of the photodegradable base, there is an onium salt compound that is decomposed by exposure and loses acid diffusion controllability. Specific examples of such an onium salt compound include a sulfonium salt compound represented by the formula (8) and an iodonium salt compound represented by the formula (9).

（式（８）におけるＲ^１８〜Ｒ^２０、および式（９）におけるＲ^２１〜Ｒ^２２は、相互に独立に、水素原子、アルキル基、アルコキシル基、ヒドロキシル基、またはハロゲン原子を表す。また、式（８）および式（９）において、Ｚ⁻は、ＯＨ⁻、Ｒ^２３−ＣＯＯ⁻、Ｒ^２３−ＳＯ_３ ⁻（但し、Ｒ^２３は、アルキル基、アリール基、またはアルカリール基を表す）、または式（１０）で表されるアニオンである。）

(R ^{18 to} R ²⁰ in formula (8) and R ^{21 to} R ²² in formula (9) each independently represent a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom. In Formula (8) and Formula (9), Z ⁻ represents OH ⁻ , R ²³ —COO ⁻ , R ²³ —SO ₃ ^— (wherein R ²³ represents an alkyl group, an aryl group, or an alkaryl group). Or an anion represented by formula (10).)

（式（１０）において、Ｒ^２４は、フッ素原子で置換もしくは非置換の炭素数１〜１２の直鎖状もしくは分岐状のアルキル基、または炭素数１〜１２の直鎖状もしくは分岐状のアルコキシル基を表し、ｎは０〜２の整数を表す。）

(In the formula (10), R ²⁴ represents a linear or branched alkyl group having 1 to 12 carbon atoms substituted or unsubstituted with a fluorine atom, or a linear or branched alkoxyl having 1 to 12 carbon atoms. Represents a group, and n represents an integer of 0 to 2.)

  The content of the acid diffusion controller is preferably 0.001 to 15 parts by mass, more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the polymer (A). More preferably, it is 05-5 mass parts. If the content is more than 15 parts by mass, the sensitivity as a resist may decrease. On the other hand, if it is less than 0.001 part by mass, the pattern shape and dimensional fidelity as a resist may be lowered depending on the process conditions. In addition, these acid diffusion control agents may be used individually by 1 type, and 2 or more types may be mixed and used for them.

(Ii) Alicyclic additives:
An alicyclic additive is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.
Examples of the alicyclic additive include 1-adamantanecarboxylic acid, 2-adamantanone, 1-adamantanecarboxylic acid t-butyl, 1-adamantanecarboxylic acid t-butoxycarbonylmethyl, 1-adamantanecarboxylic acid α-butyrolactone ester. 1,3-adamantane dicarboxylic acid di-t-butyl, 1-adamantane acetate t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantane diacetate di-t-butyl, 2,5-dimethyl Adamantane derivatives such as -2,5-di (adamantylcarbonyloxy) hexane; t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid, 2-cyclohexyloxyethyl deoxycholic acid , Deoxycholic acid -Deoxycholic acid esters such as oxocyclohexyl, deoxycholic acid tetrahydropyranyl, deoxycholic acid mevalonolactone ester; lithocholic acid t-butyl, lithocholic acid t-butoxycarbonylmethyl, lithocholic acid 2-ethoxyethyl, lithocholic acid 2 -Lithocholic acid esters such as cyclohexyloxyethyl, lithocholic acid 3-oxocyclohexyl, lithocholic acid tetrahydropyranyl, lithocholic acid mevalonolactone ester; 3- (2-hydroxy-2,2-bis (trifluoromethyl) ethyl) Tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecane and the like. In addition, these alicyclic additives may be used individually by 1 type, and 2 or more types may be mixed and used for them.

(Iii) Surfactant:
A surfactant is a component that exhibits an effect of improving coating properties, striation, developability, and the like.
Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol In addition to nonionic surfactants such as distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (above, manufactured by Tochem Products), Megafax F171, F173 (above, manufactured by Dainippon Ink and Chemicals), Florad FC430, FC431 (above, manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( As mentioned above, manufactured by Asahi Glass Co., Ltd. In addition, these surfactants may be used individually by 1 type, and 2 or more types may be mixed and used for them.

(Iv) Sensitizer:
The sensitizer absorbs radiation energy and transmits the energy to the acid generator (B), thereby increasing the amount of acid produced. The apparent sensitivity of the radiation-sensitive resin composition It has the effect of improving sensitivity.
Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like. In addition, these sensitizers may be used individually by 1 type, and 2 or more types may be mixed and used for them.

(V) Fluorine atom-containing polymer (F)
When the radiation-sensitive resin composition contains the fluorine atom-containing polymer (F), when the resist film is formed, the distribution of the resist film depends on the oil repellency characteristics of the fluorine atom-containing polymer in the film. Since there is a tendency to be unevenly distributed in the vicinity of the surface, it is possible to prevent the acid generator, the acid diffusion controller, and the like from being eluted into the immersion medium during the immersion exposure.

  The fluorine-containing polymer (F) is not particularly limited as long as it has a fluorine atom, but the fluorine atom content (mass%) is preferably higher than that of the [A] polymer. [A] When the fluorine atom content is higher than that of the polymer, the degree of uneven distribution described above becomes higher, and characteristics such as water repellency and elution suppression of the resulting resist film are improved.

(Vi) Other additives:
The radiation-sensitive resin composition may contain additives other than the additives described above (hereinafter also referred to as “other additives”). Other additives include alkali-soluble resins, low-molecular alkali-solubility control agents having acid-dissociable protecting groups, antihalation agents, storage stabilizers, antifoaming agents, and the like. In addition, by including a dye or a pigment, the latent image of the exposed portion can be visualized, and the influence of halation during exposure can be reduced. Furthermore, the adhesiveness with a board | substrate can be improved by containing an adhesion assistant.

  The radiation-sensitive resin composition can be prepared as a coating liquid by dissolving the above-described constituent components in the solvent (C) and then filtering with a filter having a pore size of about 0.2 μm, and can be applied onto a substrate. it can.

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

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]:
Using GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40 ° C. under gel permeation chromatography (GPC), Monodispersed polystyrene was measured as a standard.

[ ¹³ C-NMR analysis]:
The ¹³ C-NMR analysis of each polymer was measured using “JNM-EX270” manufactured by JEOL Ltd.

[Pattern evaluation]:
The substrate for evaluation after contact hole pattern formation formed by single patterning (hereinafter also referred to as SE) and DE was observed using a scanning electron microscope (CG-4000, manufactured by Hitachi Keiki Co., Ltd.), and the resist pattern was lost. In addition, the case where there was adhesion of insoluble matter was evaluated as “bad”, and it was resolved to the bottom without hole filling / scum, and the case where a contact hole pattern was formed was evaluated as “good”.

[Etching rate evaluation]:
The substrate for evaluation after forming the contact hole pattern is observed using a simple etching apparatus, and a film with a residual film ratio after etching of 60% or less of the initial film thickness is evaluated as “defective”, which is better than 60%. The case was rated as “good”.

  Hereinafter, a method for preparing the polymer (A) will be described. In addition, the monomer (M-1)-monomer (M-26) used for preparation of a polymer (A) are shown below. In the monomer (M-1) to the monomer (M-26), the monomer that gives the repeating unit (a1) is the monomer (M-1) to the monomer (M-5), The monomer that gives the repeating unit (a2) is monomer (M-7) to monomer (M-13), and the monomer that gives the repeating unit (a3) is monomer (M-14). To the monomer (M-23), and other monomers giving the repeating unit are the monomer (M-6) and the monomer (M-24) to the monomer (M-26). .

[Polymerization Example 1] Preparation of Polymer (A-1) First, monomer (M-11) 50 mol%, monomer (M-3) 15 mol%, monomer (M-2) 35 mol%, and A monomer solution in which a polymerization initiator (dimethyl-2,2′-azobisisobutyrate (MAIB)) was dissolved in 100 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 total amount of monomers, and the use ratio of the polymerization initiator was 5 mol% with respect to the total amount of the monomer and the polymerization initiator.

On the other hand, 50 g of methyl ethyl ketone was added to a 500 mL three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. Then, it heated so that it might become 80 degreeC, stirring the inside of a flask with a magnetic stirrer. Subsequently, the prepared monomer solution was dripped in the flask over 3 hours using the dropping funnel. After completion of 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 added to 1000 g of methanol and mixed. Then suction filtration was performed. Thereafter, the powder was recovered, re-introduced into 200 g of methanol, washed and filtered. This cleaning was performed again, and the recovered powder was dried at 60 ° C. under reduced pressure. Let the obtained polymer be a polymer (A-1). This polymer (A-1) has Mw of 6,200, Mw / Mn of 1.5, and as a result of ¹³ C-NMR analysis, the content of each repeating unit derived from each monomer ( M-3) / (M-2) / (M-11) = 14.6 / 35.9 / 49.5 (mol%).

[Polymerization Examples 2 to 21] Preparation of polymers (A-2) to (A-16) and polymers (F-1) to (F-5) Polymers (A-2) to (A-16) and Polymers (F-1) to (F-5) were prepared in the same manner as in Polymerization Example 1 except that the types and amounts of monomers shown in Table 1 were used. In Table 2, the content of each repeating unit derived from each monomer by ¹³ C-NMR of each polymer, Mw, and Mw / Mn are shown.

[Example 1] Preparation of radiation-sensitive resin composition 100 parts of polymer (A-1) as polymer (A), acid generator (B-1) (triphenylsulfonium nonafluoro as acid generator (B) -N-butanesulfonate) 7.5 parts, acid diffusion inhibitor (D-1) (Nt-butoxycarbonylpyrrolidine) 0.94 parts as nitrogen-containing compound (D), polymer (F) as polymer ( F-2) 5 parts, and as solvent (C), 1287 parts of solvent (C-1) (propylene glycol monomethyl ether acetate) and 551 parts of solvent (C-2) (cyclohexanone) were added and the components were mixed. A homogeneous solution was obtained. Then, the radiation sensitive resin composition was prepared by filtering using a membrane filter with a hole diameter of 200 nm.

[Examples 2 to 16 and Comparative Example 1]
Each radiation-sensitive resin composition was prepared in the same manner as in Example 1 except that the formulation described in Table 3 was used.

  The types of acid generator, solvent, and acid diffusion controller used in Table 1 are described below.

Acid generator (B-1): Triphenylsulfonium nonafluoro-n-butanesulfonate Solvent (C-1): Propylene glycol monomethyl ether acetate Solvent (C-2): Cyclohexanone Acid diffusion controller (D-1): N -T-Butoxycarbonylpyrrolidine

[Example 17] Formation of resist pattern On a 12-inch silicon wafer, an underlayer antireflection film (trade name “ARC66”, manufactured by Brewer Science Co., Ltd.) and a trade name “Lithius Pro-i” (manufactured by Tokyo Electron Ltd.) are used. After spin coating, PB (205 ° C., 60 seconds) was performed to form a 77 nm-thick coating film.
Using the trade name “CLEAN TRACK ACT12”, the radiation-sensitive composition (1) prepared in Example 1 was spin-coated, PB (130 ° C., 60 seconds), and then cooled (23 ° C., 30 seconds). Thereby, a resist layer having a thickness of 90 nm was formed. Using the formed resist layer, the following DE pattern and SE pattern were formed and evaluated.

[DE pattern]:
Using an ArF immersion exposure apparatus (trade name “S610C”, manufactured by NIKON), a mask for pattern formation with a pattern of 48 nm line / 96 nm pitch (48 nm 1 L / 1 S) under the optical conditions of NA: 1.30 and Dipole Exposed through. Subsequently, exposure was performed through a mask for pattern formation of 48 nm line / 96 nm pitch (48 nm 1 L / 1 S) so as to be orthogonal to the previous exposure.
PEB (125 ° C., 60 seconds) on a hot plate of the product name “Lithius Pro-i”, cooled (23 ° C., 30 seconds), then paddled with butyl acetate as a developer at the GP nozzle of the developing cup. Development (10 seconds) and rinsing with 4-methyl-2-pentanol.
The substrate for evaluation on which the contact hole pattern of 48 nm hole / 96 nm pitch was formed was obtained by spin-drying by shaking off at 2000 rpm for 15 seconds.
The evaluation of the DE pattern and the etching rate of this evaluation substrate were “good”.

[SE pattern]:
Using an ArF immersion exposure apparatus (trade name “S610C”, manufactured by NIKON), NA: 1.30, cross pole optical conditions, 48 nm dot / 96 nm pitch (mask bias is +15 nm, actually on the mask) In this case, the exposure is performed through a pattern forming mask of 252 nm dots / 384 nm pitch.
PEB (125 ° C., 60 seconds) on a hot plate of the product name “Lithius Pro-i”, cooled (23 ° C., 30 seconds), then paddled with butyl acetate as a developer at the GP nozzle of the developing cup. Development (30 seconds) and rinsing with 4-methyl-2-pentanol.
The substrate for evaluation on which the contact hole pattern of 48 nm hole / 96 nm pitch was formed was obtained by spin-drying by shaking off at 2000 rpm for 15 seconds.
The evaluation of the SE pattern and the etching rate of this evaluation substrate were “good”.

[Examples 18 to 32, Comparative Example 2]
Except as described in Table 4, each evaluation substrate was obtained in the same manner as in Example 17. The evaluation results of the obtained substrates for evaluation are also shown in Table 4.

  As can be seen from Table 4, according to the resist pattern forming method using the radiation-sensitive composition of the present invention, both SE and DE have good patterns and good etching resistance. Can be formed. On the other hand, in Comparative Example 2 using the radiation-sensitive composition of Comparative Example 1, the evaluation of the SE and DP patterns was “Poor”. .

  According to the resist pattern forming method using the radiation-sensitive composition of the present invention, since a pattern exceeding the wavelength limit can be formed favorably and economically, the radiation-sensitive composition and the pattern forming method of the present invention are: It can be used very favorably in the field of microfabrication represented by the manufacture of integrated circuit elements that are expected to become increasingly finer in the future.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Resist layer 3 1st exposure part 4 2nd exposure part 5 Unexposed part

Claims (7)

A radiation-sensitive resin composition used in a resist pattern forming method in which development is performed with an organic solvent (X),
A polymer (A), a radiation sensitive acid generator (B), and a solvent (C) are contained, and the polymer (A) is represented by the following formula (1-1) to the following formula (1-7). A radiation-sensitive resin composition comprising at least one repeating unit (a2) selected from:

(In the formulas (1-1) to (1-7), R ¹ is a hydrogen atom, a methyl group, or a trifluoromethyl group. R ² is a hydrogen atom or a substituted or unsubstituted alkyl having 1 to 4 carbon atoms. R ³ represents a hydrogen atom or a methoxy group, A represents a single bond, a methylene group, a linear or branched divalent hydrocarbon group having 2 to 10 carbon atoms, an oxygen atom or a sulfur atom. B is an oxygen atom or a methylene group, R ⁴ is a single bond or a divalent linking group, R ⁵ is a monovalent organic group having a cyclic carbonate structure, p Is an integer of 2 to 3, m is 0 or 1, and n is 0 or 1. However, when n is 0, A is not a single bond and B is not a methylene group. The radiation-sensitive resin composition according to claim 1, wherein the polymer (A) further contains at least one repeating unit (a3) selected from the following formulas (2-1) to (2-4).

(In Formulas (2-1) to (2-4), R ⁶ is a hydrogen atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ⁷ is independently a hydrogen atom or a hydroxyl group. R ⁸ is a linear or branched hydroxyalkyl group having 1 to 5 carbon atoms, and L is a linear chain having 1 to 5 carbon atoms that may be substituted with an alkyl group having 1 to 5 carbon atoms. Alternatively, it is a branched divalent hydrocarbon group, M is a group represented by any of the following formulas (M1) to (M4), and q is an integer of 1 to 3.)

The radiation sensitive resin composition of Claim 1 or Claim 2 in which the said polymer (A) further contains the repeating unit (a1) represented by following formula (3).

(In Formula (3), R ¹ is a hydrogen atom, a methyl group, or a trifluoromethyl group. R ⁹ is independently a linear or branched alkyl group having 1 to 4 carbon atoms, or a carbon atom. a monovalent alicyclic hydrocarbon group or a derivative thereof having 4 to 20. However, divalent alicyclic any two R ⁹ are bonded to each other having 4 to 20 carbon atoms hydrocarbon group or A derivative thereof may be formed.)   A resist layer forming step of forming a resist layer by applying a radiation sensitive resin composition on a substrate, an exposure step of irradiating the resist layer with a photomask through a photomask, and a development developing with an organic solvent (X) A resist pattern forming method comprising the steps of: a resist pattern forming method, wherein the radiation sensitive resin composition is the radiation sensitive resin composition according to any one of claims 1 to 3.   The resist pattern forming method according to claim 4, wherein in the exposure step, the exposure is continued after the exposure.   The organic solvent (X) is at least one solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents and hydrocarbon solvents. 5. The resist pattern forming method according to 5.   The first exposure and the second exposure using a photomask for forming a line and space pattern are performed in the exposure step, and the first exposure pattern and the second exposure pattern intersect each other. The resist pattern forming method according to claim 5 or 6.

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