JP4871549B2 - Positive resist composition and pattern forming method using the same - Google Patents

Description

  The present invention relates to a positive resist composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and also in a lithography process for other photo applications, and a pattern forming method using the same. It is. In particular, the present invention relates to a positive resist composition suitable for exposure with an immersion projection exposure apparatus using far ultraviolet light having a wavelength of 300 nm or less as a light source, and a pattern forming method using the same.

With the miniaturization of semiconductor elements, the exposure light source has become shorter in wavelength and the projection lens has a higher numerical aperture (high NA). Currently, an exposure machine with NA 0.84 using an ArF excimer laser having a 193 nm wavelength as a light source has been developed. ing. The resolution and depth of focus can be expressed by the following equations as is generally well known.
(Resolving power) = k ₁ · (λ / NA)
(Depth of focus) = ± k ₂ · λ / NA ²
Where λ is the wavelength of the exposure light source, NA is the numerical aperture of the projection lens, and k ₁ and k ₂ are coefficients related to the process.

An exposure machine using a F ₂ excimer laser having a wavelength of 157 nm as a light source has been studied for higher resolution by further shortening the wavelength. Lens materials and resists used in the exposure apparatus for shorter wavelength have been studied. Because the materials used in the process are very limited, it is very difficult to stabilize the manufacturing cost and quality of the apparatus and materials, and the exposure apparatus and resist that have sufficient performance and stability within the required period are not in time. The possibility is coming out.

As a technique for increasing the resolving power in an optical microscope, a so-called immersion method in which a high refractive index liquid (hereinafter also referred to as “immersion medium”) is filled between a projection lens and a sample has been known.
This “immersion effect” means that when λ ₀ is the wavelength of the exposure light in air, n is the refractive index of the immersion medium with respect to air, θ is the convergence angle of the light beam, and NA ₀ = sin θ. The above-described resolving power and depth of focus can be expressed by the following equations.
(Resolving power) = k ₁ · (λ ₀ / n) / NA ₀
(Depth of focus) = ± k ₂ · (λ ₀ / n) / NA ₀ ²
That is, the immersion effect is equivalent to using an exposure wavelength having a wavelength of 1 / n. In other words, in the case of a projection optical system with the same NA, the depth of focus can be increased n times by immersion.
This is effective for all pattern shapes, and can be combined with a super-resolution technique such as a phase shift method and a modified illumination method which are currently being studied.

Examples of apparatuses in which this effect is applied to transfer of a fine pattern of a semiconductor element include Patent Document 1 (Japanese Patent Laid-Open No. 57-153433) and Patent Document 2 (Japanese Patent Laid-Open No. 7-220990). There is no discussion of resists suitable for immersion exposure techniques.
Patent Document 3 (Japanese Patent Laid-Open No. 10-303114) points out that it is important to control the refractive index of the immersion medium because a change in the refractive index of the immersion medium causes deterioration of the projected image due to wavefront aberration of the exposure machine. In addition, there is disclosed water in which the temperature coefficient of the refractive index of the immersion medium is controlled within a certain range and, as a suitable immersion medium, water added with an additive that lowers the surface tension or increases the surface activity. Has been. However, the disclosure of additives and the resist suitable for the immersion exposure technique are not discussed.

Recent progress of immersion exposure technology is reported in Non-Patent Document 1 (SPIE Proc 4688, 11 (2002)), Non-Patent Document 2 (J. Vac. Sci. Tecnol. B, 17 (1999)), and the like. In the case of using an ArF excimer laser as a light source, pure water (refractive index at 193 nm: 1.44) is considered to be the most promising as an immersion medium in terms of handling safety, transmittance at 193 nm, and refractive index. .
When an F ₂ excimer laser is used as a light source, a solution containing fluorine has been studied from the balance between transmittance and refractive index at 157 nm. However, a sufficient product has not yet been seen in terms of environmental safety and refractive index. It has not been issued. From the degree of immersion effect and the degree of completeness of the resist, the immersion exposure technique is considered to be installed in the ArF exposure machine earliest.

Since the resist for KrF excimer laser (248 nm), an image forming method called chemical amplification has been used as an image forming method for a resist in order to compensate for sensitivity reduction due to light absorption. Explaining by taking a positive chemical amplification image forming method as an example, the acid generator in the exposed area is decomposed by exposure to generate an acid upon exposure, and the generated acid is reacted as a reaction catalyst by post exposure baking (PEB). Is used to change an alkali-insoluble group to an alkali-soluble group, and an exposed portion is removed by alkali development.
The conventional chemically amplified resist composition is required to reduce the fluctuation of the line width of the resist pattern due to the change in the heating temperature in the baking after the exposure.

  In immersion exposure, the resist film and the optical lens are filled with an immersion medium and exposed through a photomask, and the photomask pattern is transferred to the resist film. The penetration is expected to affect the resist performance.

  When a chemically amplified resist is applied to the immersion exposure technique, the acid on the resist surface generated during exposure moves to the immersion medium, and the acid concentration on the exposed portion surface changes. This is a major problem at the beginning of the development of chemically amplified positive resists. The surface of the exposed area that occurs due to a very small amount of basic contamination of several ppb level from the environment during exposure-PEB (PED: Post Exposure time Delay). Although it seems to be very similar to acid deactivation, the influence and mechanism of immersion exposure on the resist has not yet been clarified.

  On the other hand, when a chemically amplified resist that has no problem with lithography by normal exposure is used for pattern formation by immersion exposure, the line edge roughness may be disturbed.

JP-A-57-153433 JP-A-7-220990 JP-A-10-303114 Bulletin of International Society of Optical Engineering (Proc. SPIE), 2002, 4688, 11 J.Vac.Sci.Tecnol.B, 17 (1999)

  In view of the above-described problems of the prior art, the present invention uses a positive resist composition having improved PEB temperature dependency and improved line edge roughness in pattern formation by immersion exposure and the same. An object is to provide a pattern forming method.

一般式（ＡＩ）に於いて、
Ｒ _b0 は、水素原子、ハロゲン原子、又は炭素数１〜４のアルキル基を表す。
Ａ’は、単結合、エーテル基、エステル基、カルボニル基、アルキレン基、又はこれらを組み合わせた２価の基を表す。
Ｂ ₂ は、一般式（Ｌｃ）又は一般式（ＩＩＩ−１）〜（ＩＩＩ−５）のうちのいずれか
で示される基を表す。

一般式（Ｌｃ）に於いて、
Ｒａ ₁ 、Ｒｂ ₁ 、Ｒｃ ₁ 、Ｒｄ ₁ 及びＲｅ ₁ は、各々独立に、水素原子又はアルキル基を表
す。
ｍ、ｎは、各々独立に、０〜３の整数を表し、ｍ＋ｎは、２以上６以下である。
一般式（ＩＩＩ−１）〜（ＩＩＩ−５）に於いて、
Ｒ _1b 〜Ｒ _5b は、各々独立に、水素原子、アルキル基、シクロアルキル基、アルコキシ基、アルコキシカルボニル基、アルキルスルホニルイミノ基又はアルケニル基を表す。Ｒ _1b 〜Ｒ _5b の内の２つは、結合して環を形成してもよい。
＜６＞ 樹脂（Ａ）が、下記一般式（ＩＶ）で表される基を有する繰り返し単位を有することを特徴とする上記＜１＞〜＜５＞のいずれか一項に記載のポジ型レジスト組成物。

一般式（ＩＶ）に於いて、
Ｒ _2c 〜Ｒ _4c は、各々独立に、水素原子又は水酸基を表す。ただし、Ｒ _2c 〜Ｒ _4c のうち少なくとも１つは水酸基を表す。
＜７＞ 樹脂（Ａ）が、芳香族基を有しないことを特徴とする上記＜１＞〜＜６＞のいずれか一項に記載のポジ型レジスト組成物。
＜８＞ （Ｃ）成分の樹脂の含有量が、（Ａ）成分の樹脂の質量の０．１質量％〜５質量％であることを特徴とする上記＜１＞〜＜７＞のいずれか一項に記載のポジ型レジスト組成物。
＜９＞ （Ｃ）成分の樹脂が、アルカリ可溶性基として、カルボン酸基又はフッ化アルコール基を有することを特徴とする上記＜１＞〜＜８＞のいずれか一項に記載のポジ型レジスト組成物。
＜１０＞ 浸漬露光する工程を含むレジストパターン形成方法に用いられることを特徴とする、請求項上記＜１＞〜＜９＞のいずれか一項に記載のポジ型レジスト組成物。
＜１１＞ 上記＜１＞〜＜９＞のいずれか一項に記載のポジ型レジスト組成物により形成されたレジスト膜。
＜１２＞ 上記＜１１＞に記載のレジスト膜を、露光、現像する工程を含むことを特徴とするパターン形成方法。
＜１３＞ 液浸媒体を介してレジスト膜を、露光することを特徴とする上記＜１２＞に記載のパターン形成方法。
本発明は、上記＜１＞〜＜１３＞に係る発明であるが、以降、他の事項も含めて記載している。 The present invention is a positive resist composition having the following constitution and a pattern forming method using the same, whereby the above object of the present invention is achieved.
<1> (A) A group having a structural unit derived from a (meth) acrylic acid ester having a monocyclic or polycyclic alicyclic hydrocarbon structure, having an acid-decomposable group, and alkali development by the action of an acid A resin whose solubility in liquid increases;
(B) a compound that generates an acid upon irradiation with actinic rays or radiation,
(C) an alkali-soluble resin having a glass transition temperature (Tg) of 110 ° C. or higher, having no group that can be decomposed by an acid, and having a fluorine atom or a silicon atom;
(D) Solvent
A positive resist composition comprising:
<2> The positive resist composition as described in <1> above, wherein the component (C) has a fluorine atom.
<3> (A) a resin having a group that can be decomposed by an acid and having increased solubility in an alkali developer by the action of the acid;
(B) a compound that generates an acid upon irradiation with actinic rays or radiation,
(C) an alkali-soluble resin having a glass transition temperature (Tg) of 110 ° C. or higher, having no group that can be decomposed by an acid, and having a fluorine atom;
(D) Solvent
A positive resist composition comprising:
<4> The positive type according to <3>, wherein the component (A) has a structural unit derived from a (meth) acrylic acid ester having a monocyclic or polycyclic alicyclic hydrocarbon structure. Resist composition.
<5> The positive resist composition according to any one of <1> to <4>, wherein the component (A) has a repeating unit represented by the following general formula (AI).

In general formula (AI),
R _b0 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.
A ′ represents a single bond, an ether group, an ester group, a carbonyl group, an alkylene group, or a divalent group obtained by combining these.
B ₂ is any one of General Formula (Lc) and General Formulas (III-1) to (III-5)
Represents a group represented by

In the general formula (Lc),
Ra ₁ , Rb ₁ , Rc ₁ , Rd ₁ and Re ₁ each independently represents a hydrogen atom or an alkyl group.
The
m and n each independently represents an integer of 0 to 3, and m + n is 2 or more and 6 or less.
In general formulas (III-1) to (III-5),
R _{1b to} R _5b each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylsulfonylimino group, or an alkenyl group. Two of R _{1b to} R _5b may combine to form a ring.
<6> The positive resist according to any one of <1> to <5>, wherein the resin (A) has a repeating unit having a group represented by the following general formula (IV): Composition.

In general formula (IV),
R _{2c to} R _4c each independently represents a hydrogen atom or a hydroxyl group. However, at least one of R _{2c to} R _4c represents a hydroxyl group.
<7> The positive resist composition according to any one of <1> to <6>, wherein the resin (A) does not have an aromatic group.
<8> The content of the resin as the component (C) is 0.1% by mass to 5% by mass of the mass of the resin as the component (A), and any one of the above items <1> to <7> The positive resist composition according to one item.
<9> The positive resist according to any one of <1> to <8>, wherein the resin of component (C) has a carboxylic acid group or a fluorinated alcohol group as an alkali-soluble group. Composition.
<10> The positive resist composition according to any one of <1> to <9> above, which is used in a resist pattern forming method including a step of immersion exposure.
<11> A resist film formed from the positive resist composition according to any one of <1> to <9>.
<12> A pattern forming method comprising a step of exposing and developing the resist film according to <11>.
<13> The pattern forming method as described in <12> above, wherein the resist film is exposed through an immersion medium.
Although this invention is invention which concerns on said <1>-<13>, it describes hereafter including other matters.

(1) (A) a resin having a group that can be decomposed by an acid and having increased solubility in an alkali developer by the action of the acid;
(B) a compound that generates an acid upon irradiation with actinic rays or radiation,
(C) Glass transition temperature (Tg) is 110 ° C. or higher, does not have an acid-decomposable group, and contains an alkali-soluble resin having a fluorine atom or a silicon atom, and (D) a solvent. A positive resist composition.

  (2) The positive resist composition as described in (1), which is used in a resist pattern forming method including a step of immersion exposure.

  (3) A pattern forming method comprising: forming a resist film from the positive resist composition according to (1); and exposing and developing the resist film.

  (4) The pattern forming method as described in (3), wherein the resist film is exposed through an immersion medium.

The preferred embodiments of the present invention will be further described below.
(5) The positive resist composition as described in (1) or (2), wherein the resin as the component (C) has a structural unit derived from a (meth) acrylic acid ester.

  (6) The positive resist composition according to any one of (1), (2) and (5), wherein the resin as the component (C) has a weight average molecular weight of 4000 to 50000.

  (7) The positive resist composition according to any one of (1), (2), (5) and (6), further comprising a basic compound.

  (8) The positive resist composition as described in any one of (1), (2) and (5) to (7), further comprising a surfactant.

  (9) The content of the resin as the component (C) is 0.1% by mass to 5% by mass with respect to the mass of the resin as the component (A), (1), (2) and (5) The positive resist composition according to any one of (8) to (8).

  (10) The component (A) resin has structural units derived from a (meth) acrylic acid ester having a monocyclic or polycyclic alicyclic hydrocarbon structure (1), (2) And the positive resist composition according to any one of (5) to (9).

  (11) The resin of component (A) has a structural unit derived from a (meth) acrylic acid ester having a lactone structure, (1), (2) and (5) to (10) The positive resist composition according to any one of the above.

  (12) The pattern forming method as described in (4), wherein the immersion medium is water.

  The present invention can provide a positive resist composition having improved PEB temperature dependency and improved line edge roughness in pattern formation by immersion exposure, and a pattern forming method using the same.

Hereinafter, the present invention will be described in detail.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

(A) Resin having a group that can be decomposed by an acid and having increased solubility in an alkali developer by the action of the acid The positive resist composition of the present invention has a group that can be decomposed by an acid, and the action of the acid. A resin (also referred to as “resin of component (A)” or “acid-decomposable resin (A)”) having increased solubility in an alkali developer is contained.
In the resin of component (A), an acid-decomposable group (hereinafter also referred to as “acid-decomposable group”) is a group that decomposes by the action of an acid to generate an alkali-soluble group. Since the resin (A) has an acid-decomposable group, the solubility in an alkali developer is increased by the action of an acid.
Examples of the alkali-soluble group include a carboxyl group, a hydroxyl group, and a sulfonic acid group.
A preferred group as the acid-decomposable group is a carboxyl group or a group obtained by substituting a hydrogen atom of a hydroxyl group with a group capable of leaving by the action of an acid.
Examples of the group capable of leaving by the action of an acid include —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), —C (R ₀₁ ) ( R ₀₂ ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like. More preferably, it is a tertiary alkyl ester group.

  As the acid-decomposable group, a group represented by the following general formula (I) is preferable.

In general formula (I):
R _{1 to} R ₃ each independently represents an alkyl group, a cycloalkyl group, or an alkenyl group. At least two of R _{1 to} R ₃ may be bonded to form a ring.

As the alkyl group for R _{1 to} R ₃ , an alkyl group having 1 to 8 carbon atoms is preferable, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a 2-hexyl group, and an octyl group. Groups and the like.

The cycloalkyl group of R _{1 to} R ₃ may be monocyclic or polycyclic, and specifically includes groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25.
Preferred examples of the cycloalkyl group represented by R _{1 to} R ₃ include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, and a cycloheptyl group. , Cyclooctyl group, cyclodecanyl group, and cyclododecanyl group. More preferred are an adamantyl group, a decalin residue, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group. A part of the hydrocarbon in the cycloalkyl group may be substituted with a hetero atom such as an oxygen atom.

The alkenyl group of R ₁ to R _3, preferably a number from 2 to 8 alkenyl group having a carbon, and examples thereof include a vinyl group, an allyl group, a butenyl group, a cyclohexenyl group.

The alkyl group, cycloalkyl group, and alkenyl group in R _{1 to} R ₃ may have a substituent. Examples of the substituent include an alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, a cyano group, and an ester group. The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group or a butyl group, more preferably a methyl group, an ethyl group, a propyl group or an isopropyl group. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The alkyl group and alkoxy group may further have a substituent. Examples of the substituent that the alkyl group and alkoxy group may have include a hydroxyl group, a halogen atom, and an alkoxy group.

At least two of R _{1 to} R ₃ may be linked to each other to form a ring, and in that case, may be via a hetero atom such as an oxygen atom.

  The repeating unit having a group represented by the general formula (I) may be any repeating unit, but a repeating unit represented by the following general formula (pA) is preferable.

In general formula (pA), R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. A plurality of R may be the same or different. The alkyl group of R may be substituted with a fluorine atom, a hydroxyl group or the like.
A is a single bond, a group selected from the group consisting of an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, or a urea group, or a combination of two or more groups. Represents. The alkylene group may have a substituent.
R < ₁ > -R < ₃ > is synonymous with R < ₁ > -R < ₃ > in general formula (I).

  The repeating unit represented by the general formula (pA) is most preferably a repeating unit of 2-alkyl-2-adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate.

  Specific examples of the repeating unit represented by the general formula (pA) are shown below.

  In the acid-decomposable resin (A), the content of the repeating unit having a group represented by the general formula (I) is preferably 10 to 60 mol%, more preferably 10 to 50 mol% in all repeating structural units. is there.

The acid-decomposable resin (A) may have only the group represented by the general formula (I) as an acid-decomposable group, or may have other acid-decomposable groups in combination. .
Examples of other acid-decomposable groups that the acid-decomposable resin (A) may have include, for example, —O—C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —O—C (R ₃₆ ). (R ₃₇ ) (OR ₃₉ ), —O—C (═O) —O—C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —O—C (R ₀₁ ) (R ₀₂ ) (OR ₃₉ ) , —O—C (R ₀₁ ) (R ₀₂ ) —C (═O) —O—C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ , R ₃₆ and R ₃₉ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
Note that —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ) means a group in which each group represented by R _{36 to} R ₃₈ is bonded to a carbon atom with a single bond. The same shall apply hereinafter.

  The acid-decomposable resin (A) is a repeating unit having an acid-decomposable group including a repeating unit having an acid-decomposable group represented by the general formula (I) and a repeating unit having another acid-decomposable group. The total amount is preferably 10 to 70 mol%, more preferably 20 to 65 mol%, still more preferably 25 to 50 mol% in all repeating units.

The acid-decomposable resin (A) preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure.
Although the monocyclic or polycyclic alicyclic hydrocarbon structure of the acid-decomposable resin (A) is not particularly limited, a cycloalkyl group as R _{1 to} R ₃ in the above general formula (I), a repeating unit described later Can be mentioned.
As the repeating unit having a monocyclic or polycyclic alicyclic hydrocarbon structure in the acid-decomposable resin (A), an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pVI) is used. It is preferably at least one selected from the group consisting of a repeating unit having a partial structure and a repeating unit represented by the following general formula (II-AB), and has a monocyclic or polycyclic alicyclic hydrocarbon structure ( More preferred is a structural unit derived from a (meth) acrylic acid ester.

  First, the partial structure containing the alicyclic hydrocarbon shown by general formula (pI)-general formula (pVI) is demonstrated.

In the formula, R ₁₁ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group, and Z forms an alicyclic hydrocarbon group together with a carbon atom. Represents the atomic group necessary to do.
R _{12 to} R ₁₆ each independently represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms, provided that at least one of R _{12 to} R ₁₄ , or Either R ₁₅ or R ₁₆ represents an alicyclic hydrocarbon group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic hydrocarbon group, provided that at least one of R _{17 to} R ₂₁ Represents an alicyclic hydrocarbon group. Further, either R ₁₉ or R ₂₁ represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms.
R _{22 to} R ₂₅ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic hydrocarbon group, provided that at least one of R _{22 to} R ₂₅ Represents an alicyclic hydrocarbon group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

The alkyl group in the general formulas (pI) to (pVI) and R _{12 to} R ₂₅ is a linear or branched alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, n- Examples include propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group and the like.
In addition, examples of the substituent that each alkyl group may have include an alkoxy group having 1 to 4 carbon atoms, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), acyl group, acyloxy group, cyano. Group, hydroxyl group, carboxy group, alkoxycarbonyl group, nitro group and the like.

The alicyclic hydrocarbon group in R _{12 to} R ₂₅ or the alicyclic hydrocarbon group formed by Z and a carbon atom may be monocyclic or polycyclic. Specific examples include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25. These alicyclic hydrocarbon groups may have a substituent.

  Preferred examples of the alicyclic hydrocarbon group include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Group, cyclodecanyl group, and cyclododecanyl group. More preferred are an adamantyl group, a decalin residue, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group.

  Examples of the substituent that the alicyclic hydrocarbon group may have include an alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group, and an alkoxycarbonyl group. The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, and more preferably selected from the group consisting of a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the substituent that the alkyl group, alkoxy group, alkoxycarbonyl group and the like may further have include a hydroxyl group, a halogen atom, and an alkoxy group.

  The structures represented by the general formulas (pI) to (pVI) in the resin can be used for protecting alkali-soluble groups. Examples of the alkali-soluble group include various groups known in this technical field.

  Specific examples include a carboxylic acid group, a sulfonic acid group, a phenol group, and a thiol group, and a carboxylic acid group and a sulfonic acid group are preferable.

  As the alkali-soluble group protected by the structure represented by the general formulas (pI) to (pVI) in the above resin, the hydrogen atom of the carboxyl group is preferably substituted with the structure represented by the general formula (pI) to (pVI). Structure.

  Specific examples of the repeating unit having a structure in which the hydrogen atom of the carboxyl group is substituted with the structure represented by the general formulas (pI) to (pVI) include, for example, the repeating unit represented by the general formula (pA). The thing similar to a specific example can be mentioned.

  The resin of component (A) more preferably has a repeating unit having a group represented by the general formula (1A).

In general formula (IA),
R _x represents a hydrogen atom or a methyl group.
R _y represents an alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms of R _y may be linear or branched, may be unsubstituted, and may further have a substituent. Examples of the substituent that may have include an alkoxy group having 1 to 4 carbon atoms, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an acyl group, an acyloxy group, a cyano group, a hydroxyl group, a carboxy group, An alkoxycarbonyl group, a nitro group, etc. can be mentioned.

  Examples of the repeating unit represented by the general formula (IA) include 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, and 2-propyl-2-adamantyl (meth). And repeating units derived from acrylate, 2-isopropyl-2-adamantyl (meth) acrylate, 2-butyl-2-adamantyl (meth) acrylate, 2- (3-methoxypropyl) -2-adamantyl (meth) acrylate, and the like. It is done. Preferably, repeating units derived from 2-methyl-2-adamantyl (meth) acrylate and 2-ethyl-2-adamantyl (meth) acrylate are used.

  Next, the repeating unit having an alicyclic structure represented by the general formula (II-AB) will be described.

In general formula (II-AB),
R ₁₁ ′ and R ₁₂ ′ each independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group.
Z ′ represents an atomic group for forming an alicyclic structure containing two bonded carbon atoms (C—C).

Moreover, it is preferable that the repeating unit represented by the said general formula (II-AB) is a repeating unit represented by the following general formula (II-A) or general formula (II-B).

In general formula (II-A) and general formula (II-B),
R ₁₃ ′ to R ₁₆ ′ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, —COOH, —COOR ₅ , a group that decomposes by the action of an acid, —C (═O) —XA ′. —R ₁₇ ′ represents an alkyl group or a cyclic hydrocarbon group. At least two _{members out of} R ₁₃ ′ to R ₁₆ ′ may combine to form a ring.
R ₅ represents an alkyl group, a cyclic hydrocarbon group, or the following —Y group.
X represents an oxygen atom, a sulfur atom, -NH -, - NHSO ₂ - or an -NHSO ₂ NH-.
A ′ represents a single bond or a divalent linking group.
R ₁₇ ′ represents —COOH, —COOR ₅ , —CN, a hydroxyl group, an alkoxy group, —CO—NH—R ₆ , —CO—NH—SO ₂ —R ₆ or the following —Y group.
R ₆ represents an alkyl group or a cyclic hydrocarbon group.
n represents 0 or 1.

  The -Y group;

In the —Y group, R ₂₁ ′ to R ₃₀ ′ each independently represents a hydrogen atom or an alkyl group.
a and b represent 1 or 2.

Examples of the halogen atom in the general formula (II-AB), R ₁₁ ′ and R ₁₂ ′ include a chlorine atom, a bromine atom, a fluorine atom and an iodine atom.

Formula (II-AB), as the in the alkyl group R ₁₁ 'and R _12', preferably 1 to 10 linear or branched alkyl group carbon atoms, more preferably 1 to 6 carbon atoms Or a straight chain or branched alkyl group, more preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, or a t-butyl group.

  Examples of the further substituent in the above alkyl group include a hydroxyl group, a halogen atom, a carboxyl group, an alkoxy group, an acyl group, a cyano group, and an acyloxy group. Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the acyl group include a formyl group and an acetyl group, and examples of the acyloxy group include an acetoxy group.

  The atomic group for forming the alicyclic structure of Z ′ is an atomic group that forms a repeating unit of an alicyclic hydrocarbon which may have a substituent in a resin, and among them, a bridged type alicyclic group. An atomic group for forming a bridged alicyclic structure forming a cyclic hydrocarbon repeating unit is preferred.

Examples of the skeleton of the alicyclic hydrocarbon formed include the same alicyclic hydrocarbon groups as R _{11 to} R _{25 in} the general formulas (pI) to (pVI).

The alicyclic hydrocarbon skeleton may have a substituent. Examples of such a substituent include R ₁₃ ′ to R ₁₆ ′ in the general formula (II-A) or the general formula (II-B).

  Among the repeating units having the bridged alicyclic hydrocarbon, the repeating unit represented by the general formula (II-A) or the general formula (II-B) is more preferable.

In the repeating unit represented by the general formula (II-AB), the acid-decomposable group may be contained in the aforementioned —C (═O) —XA′—R ₁₇ ′, or Z ′ forms. It may be included as a substituent that the alicyclic structure has.

The structure of the acid-decomposable group is represented by —C (═O) —X ₁ —R ₀ .
In the formula, R ₀ is a tertiary alkyl group such as t-butyl group or t-amyl group, isobornyl group, 1-ethoxyethyl group, 1-butoxyethyl group, 1-isobutoxyethyl group, 1-cyclohexyloxy. 1-alkoxyethyl group such as ethyl group, 1-methoxymethyl group, alkoxymethyl group such as 1-ethoxymethyl group, 3-oxoalkyl group, tetrahydropyranyl group, tetrahydrofuranyl group, trialkylsilyl ester group, 3- An oxocyclohexyl ester group, a 2-methyl-2-adamantyl group, a mevalonic lactone residue and the like can be mentioned. X ₁ has the same meaning as X above.

Examples of the halogen atom in the general formula (II-A), the general formula (II-B), and R ₁₃ ′ to R ₁₆ ′ include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

The alkyl group in general formula (II-A) and general formula (II-B), R ₅ , R ₆ , R ₁₃ ′ to R ₁₆ ′ is a linear or branched alkyl group having 1 to 10 carbon atoms. More preferably a linear or branched alkyl group having 1 to 6 carbon atoms, and still more preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group. Group, t-butyl group.

Examples of the cyclic hydrocarbon group in R ₅ , R ₆ and R ₁₃ ′ to R ₁₆ ′ include a cyclic alkyl group and a bridged hydrocarbon group, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, 2- List methyl-2-adamantyl group, norbornyl group, boronyl group, isobornyl group, tricyclodecanyl group, dicyclopentenyl group, nobornane epoxy group, menthyl group, isomenthyl group, neomenthyl group, tetracyclododecanyl group, etc. Can do.

Examples of the ring formed by combining at least two of R ₁₃ ′ to R ₁₆ ′ include rings having 5 to 12 carbon atoms such as cyclopentene, cyclohexene, cycloheptane, and cyclooctane.

Examples of the alkoxy group for R ₁₇ ′ include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

  Examples of further substituents in the alkyl group, cyclic hydrocarbon group, and alkoxy group include a hydroxyl group, a halogen atom, a carboxyl group, an alkoxy group, an acyl group, a cyano group, an acyloxy group, an alkyl group, and a cyclic hydrocarbon group. Can do. Examples of the halogen atom include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group. Examples of the acyl group include a formyl group and an acetyl group. Examples thereof include an acetoxy group.

  Examples of the alkyl group and cyclic hydrocarbon group include those listed above.

  The divalent linking group for A ′ is one or two selected from the group consisting of an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, and a urea group. Combinations of the above groups can be mentioned.

Various substituents of R ₁₃ ′ to R ₁₆ ′ in the general formula (II-A) or the general formula (II-B) are atomic groups for forming an alicyclic structure in the general formula (II-AB). Or it becomes a substituent of atomic group Z for forming a bridged alicyclic structure.

  Specific examples of the repeating unit represented by the general formula (II-A) or the general formula (II-B) include the following, but the present invention is not limited to these specific examples.

  In the acid-decomposable resin (A), the content of the repeating unit having a partial structure containing the alicyclic hydrocarbon represented by the general formulas (pI) to (pVI) is 20 to 70 mol% in all repeating structural units. Is more preferable, more preferably 24-65 mol%, still more preferably 28-60 mol%.

In the acid-decomposable resin (A), the content of the repeating unit represented by the general formula (II-AB) is preferably from 10 to 60 mol%, more preferably from 15 to 55 mol%, more preferably from all repeating structural units. Preferably it is 20-50 mol%.

  In the acid-decomposable resin (A), the acid-decomposable group represented by the general formula (I) and other acid-decomposable groups are represented by the general formula (pI) to the general formula (pVI). Any of a repeating unit having a partial structure containing a formula hydrocarbon, a repeating unit represented by formula (II-AB), and a repeating unit of other copolymerization component as described later may be included.

  Moreover, it is preferable that acid-decomposable resin (A) has a lactone group, More preferably, it represents with either the following general formula (Lc) or the following general formula (III-1)-(III-5). It has a repeating unit having a group having a lactone structure, and the group having a lactone structure may be directly bonded to the main chain.

In the general formula (Lc),
Ra ₁ , Rb ₁ , Rc ₁ , Rd ₁ and Re ₁ each independently represents a hydrogen atom or an alkyl group.
m and n each independently represents an integer of 0 to 3, and m + n is 2 or more and 6 or less.

In general formulas (III-1) to (III-5),
R _{1b to} R _5b each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylsulfonylimino group, or an alkenyl group. Two of R _{1b to} R _5b may combine to form a ring.

R _{1 to} Re ₁ alkyl groups in general formula (Lc) and R _{1b to} R _5b alkyl groups, alkoxy groups, alkoxycarbonyl groups, alkyls in general formulas (III-1) to (III-5) Examples of the alkyl group in the sulfonylimino group include linear and branched alkyl groups, which may have a substituent.

  Preferred substituents include an alkoxy group having 1 to 4 carbon atoms, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), an acyl group having 2 to 5 carbon atoms, an acyloxy group having 2 to 5 carbon atoms, and cyano. A group, a hydroxyl group, a carboxy group, an alkoxycarbonyl group having 2 to 5 carbon atoms, a nitro group, and the like.

As the repeating unit having a group having a lactone structure represented by the general formula (Lc) or any one of the general formulas (III-1) to (III-5), the above general formula (II-A) or (II- B) wherein at least one of R ₁₃ ′ to R ₁₆ ′ has a group represented by general formula (Lc) or general formula (III-1) to (III-5) (for example, R in —COOR ₅ ) ₅ represents a group represented by general formula (Lc) or general formulas (III-1) to (III-5)), or a repeating unit represented by the following general formula (AI), and lactone A structural unit derived from a (meth) acrylic acid ester having a structure is preferable.

In general formula (AI),
R _b0 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. As a preferable substituent which the alkyl group of R _b0 may have, as a preferable substituent which the alkyl group as R _1b in the general formulas (III-1) to (III-5) may have. What was illustrated previously is mentioned.
Examples of the halogen atom for R _b0 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R _b0 is preferably a hydrogen atom.
A ′ represents a single bond, an ether group, an ester group, a carbonyl group, an alkylene group, or a divalent group obtained by combining these.
B ₂ represents a group represented by general formula (Lc) or any one of general formulas (III-1) to (III-5).

  Specific examples of the repeating unit having a group having a lactone structure are shown below, but the present invention is not limited thereto.

  The acid-decomposable resin (A) may have a repeating unit having a group represented by the following general formula (IV).

In general formula (IV),
R _{2c to} R _4c each independently represents a hydrogen atom or a hydroxyl group. However, at least one of R _{2c to} R _4c represents a hydroxyl group.

  The group represented by the general formula (IV) is preferably a dihydroxy body or a monohydroxy body, and more preferably a dihydroxy body.

As the repeating unit having a group represented by the general formula (IV), at least one of R ₁₃ ′ to R ₁₆ ′ in the general formula (II-A) or (II-B) is represented by the general formula (IV ) (For example, R _{5 in} —COOR ₅ represents a group represented by the general formula (IV)), or a repeating unit represented by the following general formula (AII). it can.

In general formula (AII):
R _1c represents a hydrogen atom or a methyl group.
R _{2c to} R _4c each independently represents a hydrogen atom or a hydroxyl group. However, at least one of R _{2c to} R _4c represents a hydroxyl group. Those in which two of R _{2c to} R _4c are hydroxyl groups are preferred.

  Although the specific example of the repeating unit which has a structure represented by general formula (AII) below is given, it is not limited to these.

  The acid-decomposable resin (A) may have a repeating unit represented by the following general formula (V).

In the general formula (V),
Z ₂ represents —O— or —N (R ₄₁ ) —. R ₄₁ represents a hydrogen atom, a hydroxyl group, an alkyl group, or —OSO ₂ —R ₄₂ . R ₄₂ represents an alkyl group, a cycloalkyl group or a camphor residue. The alkyl group, cycloalkyl group, and camphor residue of R ₄₁ and R ₄₂ may be substituted with a halogen atom (preferably a fluorine atom).

  Examples of the repeating unit represented by the general formula (V) include, but are not limited to, the following specific examples.

  In addition to the above repeating structural units, the acid-decomposable resin (A) has dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required properties of resist, resolving power, heat resistance, sensitivity. Various repeating structural units can be contained for the purpose of adjusting the above.

  Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

Thereby, the performance required for the resin of component (A), in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Fine adjustment such as dry etching resistance can be performed.

  As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating structural units may be copolymerized.

  In the acid-decomposable resin (A), the molar ratio of each repeating structural unit is the resist dry etching resistance, the standard developer suitability, the substrate adhesion, the resist profile, and the general required performance of the resist, resolving power and heat resistance. It is appropriately set to adjust the property, sensitivity, etc.

  In addition, the content of the repeating structural unit based on the monomer of the further copolymer component in the resin can also be appropriately set according to the performance of the desired resist. 99 mol% with respect to the total number of moles of the repeating structural unit having a partial structure containing the alicyclic hydrocarbon represented by (pVI) and the repeating unit represented by the above general formula (II-AB) The following is preferable, More preferably, it is 90 mol% or less, More preferably, it is 80 mol% or less.

In particular, the content of the above-described repeating unit having a group having a lactone structure and the repeating unit having a group represented by the general formula (IV) (hydroxyadamantane structure) is as follows.
The total number of moles of the repeating structural unit having a partial structure containing an alicyclic hydrocarbon represented by the general formulas (pI) to (pVI) and the repeating unit represented by the general formula (II-AB) for,
The content of the repeating unit having a group having a lactone structure is preferably 1 to 70 mol%, more preferably 10 to 70 mol%,
Content of the repeating unit which has group represented by general formula (IV) becomes like this. Preferably it is 1-70 mol%, More preferably, it is 1-50 mol%.

  When the composition of the present invention is for ArF exposure, the resin preferably has no aromatic group from the viewpoint of transparency to ArF light.

The acid-decomposable resin (A) can be synthesized according to a conventional method (for example, radical polymerization).
For example, as a general synthesis method, monomer species are charged into a reaction vessel in a batch or in the course of reaction, and if necessary, a reaction solvent such as ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, methyl ethyl ketone, A ketone such as methyl isobutyl ketone, an ester solvent such as ethyl acetate, and the composition of the present invention such as propylene glycol monomethyl ether acetate described below are dissolved in a solvent that dissolves uniformly and then nitrogen, argon, etc. Polymerization is started using a commercially available radical initiator (azo initiator, peroxide, etc.) as necessary under an inert gas atmosphere. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is usually 20% by mass or more, preferably 30% by mass or more, and more preferably 40% by mass or more. The reaction temperature is usually from 10 ° C to 150 ° C, preferably from 30 ° C to 120 ° C, more preferably from 50 to 100 ° C.

  Each of the above repeating structural units may be used alone or in combination. In the present invention, the resins may be used alone or in combination.

  The weight average molecular weight of the acid-decomposable resin (A) is preferably 1,000 to 200,000, more preferably 3000 to 20000 as a polystyrene-converted value by a gas permeation chromatography (GPC) method. By making the weight average molecular weight 1,000 or more, heat resistance and dry etching resistance can be improved, and by making the weight average molecular weight 200,000 or less, developability can be improved. In addition, the viscosity is lowered and the film forming property can be improved.

The molecular weight distribution (Mw / Mn, also referred to as dispersity) is usually 1 to 5, preferably 1 to 4, more preferably 1 to 3. The molecular weight distribution is preferably 5 or less from the viewpoint of resolution, resist shape, resist pattern side wall, roughness, and the like.
The amount of residual monomer in the acid-decomposable resin (A) is preferably 0 to 10% by mass, and more preferably 0 to 5% by mass.

  In the positive resist composition of the present invention, the amount of the acid-decomposable resin (A) is preferably 40 to 99.99% by mass, more preferably 50 to 99.97% by mass, based on the total solid content of the resist. .

(B) Compound that generates an acid upon irradiation with actinic rays or radiation A compound that generates an acid upon irradiation with actinic rays or radiation (hereinafter referred to as “acid generator”) used in the positive resist composition of the present invention. Is described below.
The acid generator used in the present invention can be selected from compounds generally used as an acid generator.
In other words, photoinitiators for photocationic polymerization, photoinitiators for radical photopolymerization, photodecolorants for dyes, photochromic agents, or active rays or radiations such as far ultraviolet rays and X-rays used in micro resists, etc. A known compound that generates an acid by irradiation and a mixture thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407. JP, 63-26653, JP, 55-164824, JP, 62-69263, JP, 63-146038, JP, 63-163452, JP, 62-153853, The compounds described in JP-A 63-146029 can be used.

  Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

  Preferred compounds among the acid generators include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion.

The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1-30, preferably 1-20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group.
The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).

Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.

In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

  More preferred (ZI) components include compounds (ZI-1), (ZI-2) and (ZI-3) described below.

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.

In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group.

  Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, aryldicycloalkylsulfonium compounds, and the like.

  Examples of the aryl group of the arylsulfonium compound include an aryl group composed of a hydrocarbon and a heteroaryl group having a hetero atom such as a nitrogen atom, a sulfur atom, or an oxygen atom. The aryl group composed of hydrocarbon is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. Examples of the heteroaryl group include a pyrrole group, an indole group, a carbazole group, a furan group, and a thiophene group, and an indole group is preferable. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

  The alkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec- Examples thereof include a butyl group and a t-butyl group.

  The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (e.g., having from 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms ), An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, a phenylthio group, or the like, as a substituent. Preferred substituents are a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms, particularly preferably an alkyl having 1 to 4 carbon atoms. Group, an alkoxy group having 1 to 4 carbon atoms. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Examples of the non-nucleophilic anion as X ⁻ include a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methyl anion.

  A non-nucleophilic anion is an anion that has an extremely low ability to cause a nucleophilic reaction, and is an anion that can suppress degradation over time due to an intramolecular nucleophilic reaction. This improves the temporal stability of the resist.

  Examples of the sulfonate anion include an aliphatic sulfonate anion, an aromatic sulfonate anion, and a camphor sulfonate anion.

  Examples of the carboxylate anion include an aliphatic carboxylate anion, an aromatic carboxylate anion, and an aralkylcarboxylate anion.

  Examples of the aliphatic group in the aliphatic sulfonate anion include, for example, an alkyl group having 1 to 30 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, sec- Butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl And an eicosyl group and a cycloalkyl group having 3 to 30 carbon atoms, specifically, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornyl group, a boronyl group, and the like.

  The aromatic group in the aromatic sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

  The alkyl group, cycloalkyl group, and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent.

  Examples of such substituents include nitro groups, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), carboxyl groups, hydroxyl groups, amino groups, cyano groups, and alkoxy groups (preferably having 1 to 5 carbon atoms). ), A cycloalkyl group (preferably 3 to 15 carbon atoms), an aryl group (preferably 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably 2 to 7 carbon atoms), an acyl group (preferably 2 to 12 carbon atoms). ), An alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), an alkylthio group (preferably having 1 to 15 carbon atoms), and the like. About the aryl group and ring structure which each group has, an alkyl group (preferably C1-C15) can further be mentioned as a substituent.

  Examples of the aliphatic group in the aliphatic carboxylate anion include those similar to the aliphatic group in the aliphatic sulfonate anion.

  Examples of the aromatic group in the aromatic carboxylate anion include the same aromatic groups as in the aromatic sulfonate anion.

  The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylmethyl group.

The aliphatic group, aromatic group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent include aliphatic sulfonic acid The same halogen atom, alkyl group, cycloalkyl group, alkoxy group, alkylthio group and the like as in the anion can be exemplified.

  Examples of the sulfonylimide anion include saccharin anion.

  The alkyl group in the bis (alkylsulfonyl) imide anion and tris (alkylsulfonyl) methyl anion is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, An isobutyl group, a sec-butyl group, a pentyl group, a neopentyl group, and the like can be given. These alkyl groups may have a substituent, and examples of the substituent include a halogen atom, an alkyl group substituted with a halogen atom, an alkoxy group, an alkylthio group, and the like, which are substituted with a fluorine atom. Alkyl groups are preferred.

  Examples of other non-nucleophilic anions include fluorinated phosphorus, fluorinated boron, and fluorinated antimony.

Examples of the non-nucleophilic anion of X ⁻ include an aliphatic sulfonate anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom, and an alkyl group. A bis (alkylsulfonyl) imide anion substituted with a fluorine atom and a tris (alkylsulfonyl) methide anion wherein an alkyl group is substituted with a fluorine atom are preferred. The non-nucleophilic anion is particularly preferably a perfluoroaliphatic sulfonic acid anion having 4 to 8 carbon atoms, an aromatic sulfonic acid anion having a fluorine atom, most preferably a nonafluorobutanesulfonic acid anion, a perfluorooctanesulfonic acid anion, It is a pentafluorobenzenesulfonic acid anion and 3,5-bis (trifluoromethyl) benzenesulfonic acid anion.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group not containing an aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, or an alkoxycarbonylmethyl group, particularly preferably Is a linear, branched 2-oxoalkyl group.

The alkyl group as R _{201 to} R ₂₀₃ may be either linear or branched, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, or a propyl group. Butyl group, pentyl group and the like. More preferable examples of the alkyl group include a 2-linear or branched oxoalkyl group and an alkoxycarbonylmethyl group.

The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably a cycloalkyl group having 3 to 10 carbon atoms, e.g., cyclopentyl, cyclohexyl group and a norbornyl group. More preferred examples of the cycloalkyl group include a 2-oxocycloalkyl group.

  The 2-oxoalkyl group may be linear, branched or cyclic, and preferably includes a group having> C═O at the 2-position of the above alkyl group or cycloalkyl group.

  The alkoxy group in the alkoxycarbonylmethyl group is preferably an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group).

R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

  The compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
R _x and R _y each independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group.

Any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom and a sulfur atom. , An ester bond and an amide bond may be included. Examples of the group formed by combining any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y include a butylene group and a pentylene group.

Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (ZI).

The alkyl group as R _{1c to} R _7c is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, A linear or branched pentyl group can be exemplified.

The cycloalkyl group as R _{1c to} R _7c is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopentyl group and a cyclohexyl group.

The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Preferably, any one of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c is 2 ~ 15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group and cycloalkyl group as R _x and R _y include the same alkyl groups and cycloalkyl groups as R _{1c to} R _{7c, such} as a 2-oxoalkyl group and a 2-oxocycloalkyl group. An alkoxycarbonylmethyl group is more preferable.

Examples of the 2-oxoalkyl group and 2-oxocycloalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .

Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .

R _x and R _y are preferably an alkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more.

In general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.

Examples of the aryl group of R _{204 to} R ₂₀₇ include an aryl group composed of a hydrocarbon and a heteroaryl group having a hetero atom such as a nitrogen atom, a sulfur atom, or an oxygen atom. The aryl group composed of hydrocarbon is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. Examples of the heteroaryl group include a pyrrole group, an indole group, a carbazole group, a furan group, and a thiophene group, and an indole group is preferable.

The alkyl group as R ₂₀₄ to R ₂₀₇ is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group.

The cycloalkyl group as R ₂₀₄ to R ₂₀₇ is preferably a cycloalkyl group having 3 to 10 carbon atoms, e.g., cyclopentyl, cyclohexyl group and a norbornyl group.

The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.

X ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as X ^{− in} formula (ZI).

  Preferred examples of the acid generator include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI).

In general formula (ZIV):
Ar ₃ each independently represents an aryl group.
In general formulas (ZV) and (ZVI),
R ₂₀₈ each independently represents an alkyl group, a cycloalkyl group or an aryl group, and is the same as the alkyl group, cycloalkyl group or aryl group as R _{204 to} R ₂₀₇ in the general formulas (ZII) to (ZIII). is there.
A represents an alkylene group, an alkenylene group or an arylene group.

  Among the acid generators, compounds represented by the general formulas (ZI) to (ZIII) are more preferable.

  Specific examples of the acid generator are listed below, but the present invention is not limited thereto.

An acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the acid generator in the positive resist composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 based on the total solid content of the resist composition. -7% by mass.

(C) Alkali-soluble resin having a glass transition temperature (Tg) of 110 ° C. or higher, no group that can be decomposed by an acid, and having a fluorine atom or a silicon atom. Alkali-soluble resin ("resin of component (C)" or "alkali-soluble resin (C)" having a temperature (Tg) of 110 ° C or higher, having no group that can be decomposed by an acid, and having a fluorine atom or a silicon atom ").
The introduction of the alkali-soluble resin (C) into the positive resist composition can be expected to reduce the temporal change in the affinity between the resist film and the immersion medium, particularly in immersion exposure. It is thought to improve.

The alkali-soluble resin (C) is an alkali-soluble resin, that is, a resin that is soluble in an alkali developer as described later (usually an alkaline aqueous solution having a pH of 10.0 to 15.0, 23 ° C.).
Therefore, the alkali-soluble resin (C) has an alkali-soluble group and / or a group that is hydrolyzed and solubilized by an alkali developer.
Examples of the alkali-soluble group include a phenolic hydroxyl group, a carboxylic acid group, a fluorinated alcohol group, a sulfonic acid group, a sulfonamide group, a (sulfonyl) (carbonyl) methylene group, a group having an active methylene group, and the like. Specific examples of the group having an active methylene group include —C (═O) —CH ₂ —C (═O) —, —C (═O) —CHR—C (═O) — (R is an alkyl group) , -C (= O) -CH ( C (= O)) 2 -, - SO 2 -CH 2 -C (= O) - , and the like.
Preferred alkali-soluble groups include carboxylic acid groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), sulfonic acid groups, and sulfonamide groups.

  Examples of the group that is hydrolyzed and solubilized with an alkali developer include a lactone group, an ester group, a sulfonamide group, and an acid anhydride, and preferably a lactone group, a sulfonamide group, and an acid anhydride.

  The alkali-soluble resin (C) is at least one of the repeating units represented by the following general formulas (Ca) to (Cf) as a repeating unit having an alkali-soluble group and / or a group that is hydrolyzed and solubilized with an alkali developer. It is preferable to have one type, and among these, (meth) acrylic acid ester-based repeating units are more preferable.

In general formulas (Ca) to (Cd),
Xc represents a hydrogen atom or an alkyl group.
Rc ₁ each independently represent a hydrogen atom or an alkyl group.
Rf ₁ and Rf ₂ each independently represents a hydrogen atom or an alkyl group. However, at least one of Rf ₁ and Rf ₂ is a fluorine-substituted alkyl group. Rf ₁ and Rf ₂ are preferably perfluoromethyl groups.
Q represents a single bond or a divalent linking group.
Qc represents a single bond or an nc + 1 valent linking group.
nc represents a positive integer. nc is preferably 1 to 5, more preferably 1 to 2.
The linking group is not particularly limited, but any one of an alkylene group, a cycloalkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, and a urea group, or two or more thereof A combination of these groups is preferred. Of these, an alkylene group, a cycloalkylene group, an ester group, or a combination of two or more of these groups is particularly preferable.

In general formula (Ce),
R _{1a to} R _4a are each independently a hydrogen atom, a group having a hexafluoroisopropanol group or a hexafluoroisopropanol group (preferably an alkyl having 1 to 3 carbon atoms substituted with a hexafluoroisopanol group). Group), and at least one of R _{1a to} R _4a represents a hexafluoroisopanol group or a group having a hexafluoroisopanol group.
na represents 0 or 1.

  Hereinafter, specific examples of the repeating unit having an alkali-soluble group and / or a group that is hydrolyzed and solubilized with an alkali developer will be described, but the present invention is not limited thereto.

The alkali-soluble resin (C) has a fluorine atom or a silicon atom.
The alkali-soluble resin (C) is a repeating unit represented by the general formula (Cc), a repeating unit represented by the general formula (Ce), or a following general formula (Cg) as a repeating unit having a fluorine atom or a silicon atom. It is preferable to have at least one type of repeating unit selected from the repeating unit represented by general formula (Ch) and the repeating unit represented by general formula (Ci). A (meth) acrylic acid ester-based repeating unit is more preferable.

In general formula (Cg),
Xd represents a hydrogen atom, a halogen atom or an alkyl group.
Rd represents a hydrogen atom, a halogen atom, an alkyl group, a carboxyl group, a hydroxyl group or a lactone group.
However, at least one of Xd and Rd represents a fluorine atom or an alkyl group substituted with a fluorine atom or a silicon atom.
Q represents a single bond or a divalent linking group.
The linking group is not particularly limited, but any one of an alkylene group, a cycloalkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, and a urea group, or two or more thereof A combination of these groups is preferred. Of these, an alkylene group, a cycloalkylene group, an ester group, or a combination of two or more of these groups is particularly preferable.

In the general formula (Ch),
Fa, Fb, Fc and Fd each independently represent a hydrogen atom, a fluorine atom or an alkyl group substituted with a fluorine atom. However, at least one of Fa, Fb, Fc and Fd represents a fluorine atom or an alkyl group substituted with a fluorine atom.

In general formula (Ci):
Fe, Ff, Fg, Fh and Fi each independently represent a hydrogen atom, a fluorine atom or an alkyl group substituted with a fluorine atom. However, at least one of Fe, Ff, Fg, Fh and Fi represents a fluorine atom or an alkyl group substituted with a fluorine atom.

  Hereinafter, although the specific example of the repeating unit which has a fluorine atom or a silicon atom is given, this invention is not limited to this.

  The alkali-soluble resin (C) does not have a group that can be decomposed by an acid.

The glass transition temperature (Tg) of alkali-soluble resin (C) is 110 degreeC or more, Preferably it is 110-300 degreeC, More preferably, it is 120-200 degreeC, More preferably, it is 150-200 degreeC.
The Tg of the alkali-soluble resin (C) can be measured by differential scanning calorimeter.
In the case of a resin having a repeating unit, Tg is controlled by selecting a repeating unit (for example, selecting an acrylic repeating unit or a methacrylic repeating unit, a type of alicyclic structure, a distance from the polymer main chain of the alicyclic structure, etc.) and This is possible depending on the copolymerization ratio and the molecular weight of the resin. In the (meth) acrylic resin, as a method for increasing Tg, a methacrylic repeating unit is selected, an alicyclic group generally having a bridging structure is selected as the alicyclic structure, and the distance from the polymer main chain of the alicyclic structure There is a method of decreasing the molecular weight, increasing the copolymerization ratio of repeating units having such a structure, and increasing the molecular weight.

  The alkali-soluble resin (C) can be synthesized by a conventional method (for example, radical polymerization as in the synthesis of the acid-decomposable resin (A) described above).

  The amount of the alkali-soluble group (acid group) is preferably 2 to 10 meq / g, more preferably 2 to 8 meq / g, as the acid value of the alkali-soluble resin (C). The acid value is determined by measuring the amount (mg) of potassium hydroxide required to neutralize the alkali-soluble resin (C).

In the alkali-soluble resin (C), the content of the repeating unit having an alkali-soluble group and / or a group that is hydrolyzed and solubilized with an alkali developer is 1 to 50 mol% in all repeating units. Is preferable, and it is more preferable that it is 5-30 mol%.
In the alkali-soluble resin (C), the content of the repeating unit having a fluorine atom or a silicon atom is preferably 1 to 90 mol%, more preferably 5 to 50 mol% in all repeating units. preferable.

The weight average molecular weight of the alkali-soluble resin (C) is preferably 4000 to 50000.
The residual monomer amount of the alkali-soluble resin (C) is preferably 0 to 10% by mass, and more preferably 0 to 5% by mass.
The molecular weight distribution (Mw / Mn, also referred to as dispersion degree) of the alkali-soluble resin (C) is usually 1 to 5, preferably 1 to 4, and more preferably 1 to 3.

The addition amount of the alkali-soluble resin (C) in the positive resist composition is preferably 1 to 60% by mass, more preferably 1 to 40% by mass, and still more preferably 1 based on the total solid content of the resist composition. -10 mass%.
It is preferable that content of alkali-soluble resin (C) is 0.1 mass%-5 mass% of the mass of acid-decomposable resin (A).
The alkali-soluble resin (C) may be used alone or in combination.

(D) Solvent The positive resist composition of the present invention is used by dissolving each component in a predetermined solvent.
Examples of solvents that can be used include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether. Acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N- Dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, methoxybutanol, tetrahydrofuran, etc. Mention may be made of the solvent.

In this invention, you may use the mixed solvent which mixed the solvent which has a hydroxyl group in a structure, and the solvent which does not have a hydroxyl group as a solvent.
Examples of the solvent having a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Propylene glycol monomethyl ether and ethyl lactate are preferred.
Examples of the solvent having no hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are preferable, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate 2-heptanone is more preferable.
The mixing ratio (mass) of the solvent having a hydroxyl group and the solvent having no hydroxyl group is preferably 1/99 to 99/1, more preferably 10/90 to 90/10, and even more preferably 20/80 to 60. / 40. A mixed solvent containing 50% by mass or more of a solvent having no hydroxyl group is particularly preferable from the viewpoint of coating uniformity.
Using such a solvent, a resist composition having a solid content concentration of usually 3 to 25% by mass, preferably 5 to 22% by mass, more preferably 7 to 20% by mass, and still more preferably 5 to 15% by mass. Prepare.

(E) Basic compound In the composition of the present invention, performance variation (pattern T-top shape formation, sensitivity variation, pattern line width variation, etc.) and coating over time after irradiation with actinic rays or radiation and heat treatment and coating A basic compound can be used for the purpose of preventing excessive diffusion (degradation of resolution) of acid during heat treatment after performance fluctuations due to later aging, and further after irradiation with actinic rays or radiation. The basic compound is, for example, an organic basic compound having basic nitrogen, and a compound having a pKa value of a conjugate acid of 4 or more is preferably used.
Specifically, the structures of the following formulas (A) to (E) can be exemplified.

Here, R ²⁵⁰ , R ²⁵¹ and R ²⁵² may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, or 6 to 20 carbon atoms. Wherein R ²⁵¹ and R ²⁵² may combine with each other to form a ring. Examples of the substituent that each of the above groups may have include an amino group and a hydroxyl group.
R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ may be the same or different and each represents an alkyl group having 1 to 6 carbon atoms.

  Preferred examples include guanidine, aminopyridine, aminoalkylpyridine, aminopyrrolidine, indazole, imidazole, pyrazole, pyrazine, pyrimidine, purine, imidazoline, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine and the like. These compounds may have a substituent, and preferred substituents include an amino group, an aminoalkyl group, an alkylamino group, an aminoaryl group, an arylamino group, an alkyl group, an alkoxy group, an acyl group, an acyloxy group, An aryl group, an aryloxy group, a nitro group, a hydroxyl group, a cyano group, etc. are mentioned.

  Particularly preferred compounds include guanidine, 1,1-dimethylguanidine, 1,1,3,3-tetramethylguanidine, imidazole, 2-methylimidazole, 4-methylimidazole, N-methylimidazole, 2-phenylimidazole, 4 , 5-diphenylimidazole, 2,4,5-triphenylimidazole, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-diethylaminopyridine, 2- (Aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine, 2-amino-5-methylpyridine, 2-amino-6-methylpyridine, 3-aminoethylpyridine, 4- Aminoethylpyridine,

3-aminopyrrolidine, piperazine, N- (2-aminoethyl) piperazine, N- (2-aminoethyl) piperidine, 4-amino-2,2,6,6-tetramethylpiperidine,
4-piperidinopiperidine, 2-iminopiperidine, 1- (2-aminoethyl) pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2- (aminomethyl) -5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) Examples include, but are not limited to, morpholine.

A basic ammonium salt can also be used. Specific examples of the basic ammonium salt include the following compounds, but are not limited thereto.
Specifically, ammonium hydroxide, ammonium triflate, ammonium pentaflate, ammonium heptaflate, ammonium nonaflate, ammonium undecaflate, ammonium tridecaflate, ammonium pentadecaflate, ammonium methylcarboxylate, ammonium ethylcarboxylate, Ammonium propyl carboxylate, ammonium butyl carboxylate, ammonium heptyl carboxylate, ammonium hexyl carboxylate, ammonium octyl carboxylate, ammonium nonyl carboxylate, ammonium decyl carboxylate, ammonium undecyl carboxylate, ammonium dodecadecyl carboxylate, ammonium salt Decyl carboxylate, ammonium tetradecyl carboxylate, ammonium pentadecyl carboxylate, ammonium hexadecyl carboxylate, ammonium heptadecyl carboxylate, ammonium octadecyl carboxylate and the like.

  Specific examples of ammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, and tetraheptyl. Ammonium hydroxide, methyl trioctyl ammonium hydroxide, tetraoctyl ammonium hydroxide, didecyl dimethyl ammonium hydroxide, tetrakisdecyl ammonium hydroxide, dodecyl trimethyl ammonium hydroxide, dodecyl ethyl dimethyl ammonium hydroxide, didodecyl dimethyl ammonium hydroxide, Tridodecylmethylammonium hydro Side, myristylmethylammonium hydroxide, dimethylditetradecylammonium hydroxide, hexadecyltrimethylammonium hydroxide, octadecyltrimethylammonium hydroxide, dimethyldioctadecylammonium hydroxide, tetraoctadecylammonium hydroxide, diallyldimethylammonium hydroxide, (2 -Chloroethyl) -trimethylammonium hydroxide, (2-bromoethyl) trimethylammonium hydroxide, (3-bromopropyl) -trimethylammonium hydroxide, (3-bromopropyl) triethylammonium hydroxide, glycidyltrimethylammonium hydroxide, choline hydroxy (R)-(+)-(3-chloro-2-hydro Cypropyl) trimethylammonium hydroxide, (S)-(−)-(3-chloro-2-hydroxypropyl) -trimethylammonium hydroxide, (3-chloro-2-hydroxypropyl) -trimethylammonium hydroxide, (2- Aminoethyl) -trimethylammonium hydroxide, hexamethonium hydroxide, decamethonium hydroxide, 1-azoniapropellan hydroxide, petronium hydroxide, 2-chloro-1,3-dimethyl-2-imidazolinium hydroxy And 3-ethyl-2-methyl-2-thiazolinium hydroxide.

A basic compound can be used by 1 or more types, and it is more preferable to use 2 or more types.
The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of solid content of a positive resist composition, Preferably it is 0.01-5 mass%.

  The use ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

(F) Dissolution inhibitor compound that decomposes by the action of an acid to increase the solubility in an alkaline developer The positive resist composition of the present invention decomposes by the action of an acid to increase the solubility in an alkaline developer. A dissolution inhibiting compound (hereinafter also referred to as “dissolution inhibiting compound”) can be contained.
The dissolution inhibiting compound contains an acid-decomposable group, such as a cholic acid derivative containing an acid-decomposable group described in Proceeding of SPIE, 2724,355 (1996), in order not to lower the permeability of 220 nm or less. Preferred are alicyclic or aliphatic compounds. Examples of the acid-decomposable group and alicyclic structure are the same as those described for the acid-decomposable resin (A).
The molecular weight of the dissolution inhibiting compound is preferably 3000 or less, more preferably 300 to 3000, and still more preferably 500 to 2500.

  The addition amount of the dissolution inhibiting compound is preferably 1 to 30% by mass and more preferably 2 to 20% by mass with respect to the total solid content of the positive resist composition.

  Specific examples of the dissolution inhibiting compound are shown below, but are not limited thereto.

(G) Surfactant The positive resist composition of the present invention can further contain (G) a surfactant. As the surfactant, one of fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, surfactant having both fluorine atom and silicon atom), or two or more kinds It is preferable to contain.

When the positive resist composition of the present invention contains the surfactant (G), improvement in sensitivity, resolution, adhesion, suppression of development defects, etc. when using an exposure light source of 250 nm or less, particularly 220 nm or less. effective.
Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

  Examples of commercially available surfactants that can be used include EFTOP EF301 and EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 and 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176 and F189. , F113, F110, F177, F120, R08 (manufactured by Dainippon Ink & Chemicals, Inc.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (manufactured by Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toa Gosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204D, 208G, 218G, 230G, 204D, 208D, 212D, 218, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy) And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

  In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopal Te - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

  In the present invention, a surfactant represented by the following general formula (W) can also be used.

In general formula (W),
R _w represents a hydrogen atom or an alkyl group.
m represents an integer of 1 to 30.
n represents an integer of 0 to 3.
p represents an integer of 0 to 5.

The alkyl group for R _w is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, or a t-butyl group. And a methyl group, an ethyl group, and a propyl group are more preferable.

  In general formula (W), it is more preferable that m is an integer of 1 to 25, n is an integer of 0 to 2, and p is an integer of 0 to 3.

Preferable specific examples of the surfactant represented by the general formula (W) include, for example, PF636 which is a commercially available product (n = 0, m = 6, p = 1, R ₁ = methyl group in the general formula (W)). PF6320 (n = 0, m = 20, p = 1, R ₁ = methyl group), PF656 (n = 1, m = 6, p = 1, R ₁ = methyl group in the general formula (W)), PF6520 (In general formula (W), n = 1, m = 20, p = 1, R ₁ = methyl group) (above, manufactured by OMNOVA) and the like can be mentioned.

  These surfactants may be used alone or in several combinations.

  (G) The usage-amount of surfactant becomes like this. Preferably it is 0.01-5 mass% with respect to positive resist composition whole quantity (except a solvent), More preferably, it is 0.1-3 mass%.

(H) Alkali-soluble resin The positive resist composition of the present invention can further contain a resin that is soluble in an alkali developer, thereby improving the sensitivity.
In the present invention, a novolak resin having a molecular weight of about 1000 to 20000 and a polyhydroxystyrene derivative having a molecular weight of about 3000 to 50000 can be used as such a resin, since these have a large absorption with respect to light of 250 nm or less. It is preferable to use a partly hydrogenated amount or 30% by mass or less of the total resin amount.
A resin having a carboxyl group as an alkali-soluble group can also be used. The resin having a carboxyl group preferably has a monocyclic or polycyclic alicyclic hydrocarbon group in order to improve dry etching resistance. Specifically, a methacrylic acid ester and (meth) acrylic acid copolymer having an alicyclic hydrocarbon structure that does not exhibit acid decomposability, or a (meth) acrylic acid ester having an alicyclic hydrocarbon group having a carboxyl group at the terminal And the like.
The addition amount of such an alkali-soluble resin is usually 30% by mass or less with respect to the total amount of the resin including the acid-decomposable resin (A).

(I) Carboxylic acid onium salt The positive resist composition of the present invention may contain a carboxylic acid onium salt.
Examples of carboxylic acid onium salts in the present invention include carboxylic acid sulfonium salts, carboxylic acid iodonium salts, and carboxylic acid ammonium salts. In particular, as the carboxylic acid onium salt, an iodonium salt and a sulfonium salt are preferable. Furthermore, in the carboxylic acid onium salt of the present invention, it is preferable that the carboxylate residue does not contain an aromatic group or a carbon-carbon double bond. As a particularly preferable anion moiety, a linear, branched, monocyclic or polycyclic alkylcarboxylic acid anion having 1 to 30 carbon atoms is preferable. More preferably, an anion of a carboxylic acid in which some or all of these alkyl groups are fluorine-substituted is preferable. The alkyl chain may contain an oxygen atom. This ensures transparency with respect to light of 220 nm or less, improves sensitivity and resolution, and improves density dependency and exposure margin.

  Fluoro-substituted carboxylic acid anions include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorocyclohexanecarboxylic acid, 2 , 2-bistrifluoromethylpropionic acid anion and the like.

  These carboxylic acid onium salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

  The content of the carboxylic acid onium salt in the composition is suitably from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, more preferably 1%, based on the total solid content of the positive resist composition. -7% by mass.

(J) Other additives In the positive resist composition of the present invention, a dye, a plasticizer, a photosensitizer, and a compound that promotes solubility in a developer (for example, having a molecular weight of 1000 or less) are added as necessary. A phenol compound, an alicyclic compound having a carboxyl group, or an aliphatic compound).

Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to, for example, the methods described in JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, etc. It can be easily synthesized by those skilled in the art.
Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

  The metal content in the positive resist composition of the present invention is preferably 100 ppb or less.

(K) Pattern Forming Method The positive resist composition of the present invention is used by dissolving the above components in a predetermined organic solvent, preferably the mixed solvent, and applying the solution on a predetermined support as follows.
That is, a positive resist composition is formed on a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements by an appropriate coating method such as a spinner or a coater, with an arbitrary thickness (usually 50 to 500 nm).
After coating, the resist is dried by spin or baking, and after forming a resist film, exposure is performed through a mask or the like for pattern formation. Although an exposure amount can be set suitably, it is 1-100 mJ / cm < ² > normally. After exposure, preferably, spinning or / and baking are performed, development and rinsing are performed to obtain a pattern. Post-exposure baking is preferably performed, and the baking temperature is usually 30 to 300 ° C. From the above-mentioned PED point, it is better that the time from the exposure to the baking process is short.
Here, the exposure light is preferably far ultraviolet rays having a wavelength of 250 nm or less, more preferably 220 nm or less. Specific examples include KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-rays, and the like.
When exposing the resist film, exposure (immersion exposure) may be performed through an immersion medium. It is considered that the change in performance observed when the resist is applied to immersion exposure is derived from the contact of the resist surface with the immersion medium.

The immersion medium used for the immersion exposure will be described below.
The immersion medium is preferably a liquid that is transparent to the exposure wavelength and has a refractive index with a temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the resist. In the case of an ArF excimer laser (wavelength: 193 nm), it is preferable to use water from the viewpoints of availability and ease of handling in addition to the above-described viewpoints.
Further, a medium having a refractive index of 1.5 or more can be used in that the refractive index can be further improved. This medium may be an aqueous solution or an organic solvent.

When water is used as the immersion medium, the resist layer on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element is negligible in order to reduce the surface tension of the water and increase the surface activity. An additive (liquid) may be added in a small proportion. The additive is preferably an aliphatic alcohol having a refractive index substantially equal to that of water, and specifically includes methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. By adding an alcohol having a refractive index substantially equal to that of water, even if the alcohol component in water evaporates and the content concentration changes, an advantage that the change in the refractive index of the entire liquid can be made extremely small can be obtained. On the other hand, when an opaque substance or impurities whose refractive index is significantly different from that of water are mixed with respect to 193 nm light, the optical image projected on the resist is distorted. Therefore, distilled water is preferable as the water to be used. Further, pure water filtered through an ion exchange filter or the like may be used.

The electrical resistance of water is desirably 18.3 M ohm · cm or more, and the TOC (organic concentration) is desirably 20 ppb or less. Moreover, it is desirable to have deaerated.
In addition, it is possible to improve lithography performance by increasing the refractive index of the immersion medium. From such a viewpoint, an additive for increasing the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

In order to prevent the resist film from coming into direct contact with the immersion medium between the resist film made of the positive resist of the present invention and the immersion medium, an immersion medium insoluble film (hereinafter also referred to as “top coat”) is provided. It may be provided. The functions necessary for the top coat are suitability for application to the upper layer of the resist, transparency to radiation, particularly 193 nm, and poor immersion medium solubility. It is preferable that the top coat is not mixed with the resist and can be uniformly applied to the resist upper layer.
From the viewpoint of 193 nm transparency, the topcoat is preferably a polymer that does not contain an aromatic, and specifically, a hydrocarbon polymer, an acrylate polymer, a polymethacrylic acid, a polyacrylic acid, a polyvinyl ether, a silicon-containing polymer, And fluorine-containing polymers.
When peeling the top coat, a developer may be used, or a separate release agent may be used. As the release agent, a solvent having a small penetration into the resist is preferable. It is preferable that the peeling process can be performed with an alkali developer in that the peeling process can be performed simultaneously with the resist development process. From the viewpoint of peeling with an alkaline developer, the topcoat is preferably acidic, but may be neutral or alkaline from the viewpoint of non-intermixability with the resist.
The resolution is improved when there is no difference in refractive index between the topcoat and the immersion medium. When the exposure light source is an ArF excimer laser (wavelength: 193 nm), it is preferable to use water as the immersion medium, so that the top coat for ArF immersion exposure is close to the refractive index of water (1.44). Is preferred. A thin film is more preferable from the viewpoint of transparency and refractive index.

  When an organic solvent is used as the immersion medium, it is preferable to use a water-soluble top coat.

Examples of the alkaline developer used in the development step include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, and primary amines such as ethylamine and n-propylamine. Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide Alkaline aqueous solutions of cyclic amines such as quaternary ammonium salts such as pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline aqueous solution.
As the rinsing liquid, pure water can be used, and an appropriate amount of a surfactant can be added.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 15.0.

  Further, after the development process or the rinsing process, a process of removing the developer or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, the content of this invention is not limited by this.

Synthesis Example 1 (Synthesis of acid-decomposable resin (21))
A mixture of norbornene carboxylic acid t-Bu ester, norbornene carboxylic acid, norbornene carboxylic acid 2-hydroxyethyl ester and maleic anhydride in a molar ratio (30: 10: 10: 50) was dissolved in tetrahydrofuran, and the solid content was 50% by mass. A solution was prepared. This was charged into a three-necked flask and heated at 60 ° C. under a nitrogen stream. When the reaction temperature was stabilized, 5 mol% of radical initiator V-60 manufactured by Wako Pure Chemical Industries, Ltd. was added to initiate the reaction. After heating for 6 hours, the reaction mixture was diluted twice with tetrahydrofuran, and then poured into hexane in an amount 5 times that of the reaction solution to precipitate a white powder. This was dissolved again in THF, and the solution was added to 5 times the amount of hexane to precipitate a white powder. The precipitated powder was filtered out and dried to obtain an acid-decomposable resin (21) having the following structure, which was the target product. When the molecular weight analysis (RI analysis) by GPC of the obtained acid-decomposable resin (21) was tried, it was 7900 (weight average) in terms of polystyrene. The molecular weight dispersity was 1.91.

Synthesis Example 2 (Synthesis of alkali-soluble resin (D-1))
1,1,1,3,3,3-hexafluoro-2- (4- (1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl) cyclohexyl) propane-2 -20 g of yl methacrylate and 2.9 g of 2-methyl-acrylic acid 2,2,2-trifluoro-1-trifluoromethyl-ethyl ester were dissolved in 70 mL of propylene glycol monomethyl ether acetate. 3 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added to this solution, and this was added dropwise to 10 mL of a propylene glycol monomethyl ether acetate solution heated to 80 ° C. over 6 hours in a nitrogen atmosphere. The reaction liquid was stirred for 2 hours after completion | finish of dripping, and the reaction liquid (D-1) was obtained. After completion of the reaction, the reaction solution (D-1) was cooled to room temperature, crystallized in 4.5 times the amount of hexane, and the precipitated white powder was collected by filtration to obtain the target alkali-soluble resin (D-1). Was recovered.
The weight average molecular weight in terms of standard polystyrene determined by GPC measurement was 8700, and the molecular weight dispersity was 1.89.

  Hereinafter, structures, molar ratios, weight average molecular weights, and molecular weight dispersities of the acid-decomposable resins (1) to (20) are shown.

  Hereinafter, the structures of the alkali-soluble resins (D-1) to (D-6) are shown.

  Table 1 below shows the composition ratio (molar ratio), weight average molecular weight, molecular weight dispersity, and glass transition temperature (Tg) of the alkali-soluble resins (D-1) to (D-6).

Examples 1-21 and Comparative Examples 1-3
<Resist preparation>
The components shown in Table 2 below were dissolved in a solvent to prepare a solution having a solid content concentration of 10% by mass, and this was filtered through a 0.1 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist solution was evaluated by the following method, and the results are shown in Table 2.

Abbreviations in Table 2 are as follows.
[Basic compounds]
N-1, N, N-dibutylaniline N-2; N, N-dipropylaniline N-3; N, N-dihydroxyethylaniline N-4: 2,4,5-triphenylimidazole N-5; 2 , 6-Diisopropylaniline N-6; Hydroxyantipyrine [Surfactant]
W-1; Megafac F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2; Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3; Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based) W-4; Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
〔solvent〕
SL-1: cyclopentanone SL-2: cyclohexanone SL-3: 2-methylcyclohexanone SL-4; propylene glycol monomethyl ether acetate SL-5: ethyl lactate SL-6: propylene glycol monomethyl ether SL-7: 2-heptanone SL-8: γ-butyrolactone SL-9: propylene carbonate In Table 2, the ratio when a plurality of components are used is a mass ratio.

<Resist Evaluation-1>
ARC29A manufactured by Brewer Science Co., Ltd. was uniformly applied to a silicon wafer with a spin coater at 78 nm, and heat-dried at 205 ° C. for 60 seconds to form an antireflection film. Thereafter, each positive resist solution immediately after preparation was applied with a spin coater and dried (PB) at a temperature of 120 ° C. for 90 seconds to form a 300 nm resist film.
This resist film was exposed with an ArF excimer laser stepper (PAS5500 / 1100 NA = 0.75 (2/3 annular illumination) manufactured by ASML) through a mask, and heated at 120 ° C. immediately after exposure. The resist pattern was obtained by developing with a methylammonium hydroxide aqueous solution (2.38 mass%) for 60 seconds, rinsing with pure water, and spin drying. The line width of the resist pattern was observed with a scanning electron microscope (S-9220 manufactured by Hitachi), and the exposure amount (Eo) at which the 90 nm line and space pattern was finished at a line / space ratio of 1: 1 was confirmed.
Next, in the same manner as described above, ARC29A manufactured by Brewer Science Co., Ltd. was uniformly applied to 78 nm on a silicon wafer with a spin coater, and heat-dried at 205 ° C. for 60 seconds to form an antireflection film. Thereafter, each positive resist solution immediately after preparation was applied with a spin coater and dried (PB) at a temperature of 120 ° C. for 90 seconds to form a 300 nm resist film.
The resist film is irradiated with an energy of exposure amount (Eo) with an ArF excimer laser stepper (PAS5500 / 1100 NA = 0.75 (2/3 annular illumination) manufactured by ASML) through a mask, and 118 ° C. and 122 ° C. After being heated at the two temperatures for 60 seconds, developed with a tetramethylammonium hydroxide aqueous solution (2.38 mass%) for 60 seconds, rinsed with pure water, and then spin-dried to obtain a resist pattern. The resist pattern was observed with a scanning electron microscope (Hitachi S-9220) for the resist pattern, and the line widths (L ₁ and L ₂ ) with respect to heating temperatures of 118 ° C. and 122 ° C. were measured. Dependency was calculated.
PEB temperature dependency (nm / ° C.) = | L ₁ −L ₂ | / 4

<Resist Evaluation-2>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. The positive resist solution prepared thereon was applied and baked at 115 ° C. for 60 seconds to form a 200 nm resist film. The wafer thus obtained was subjected to two-beam interference exposure using the apparatus shown in FIG. 1, using water as the immersion liquid. The laser wavelength was 193 nm, and a prism that formed a 90 nm line and space pattern was used. Then, after heating at 120 ° C. for 60 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 60 seconds, rinsing with pure water, and spin drying, a resist pattern was obtained. Edge roughness was measured for the obtained pattern. Edge roughness is measured by using a length-measuring scanning electron microscope (SEM) to detect line pattern edges at a plurality of positions in a measurement monitor, and to detect the variance (3σ) of the variation in the detected positions. It was used as an index. Edge roughness values of 5 nm or less were evaluated as ◯, 5 to 10 nm as Δ, and those exceeding 10 nm as X.
In the apparatus shown in FIG. 1, 1 is a laser, 2 is an aperture, 3 is a shutter, 4, 5, 6
Denotes a reflecting mirror, 7 denotes a condenser lens, 8 denotes a prism, 9 denotes an immersion medium, 10 denotes a wafer provided with an antireflection film and a resist film, and 11 denotes a wafer stage.

  From the results of Table 2, it can be seen that the positive resist composition of the present invention is excellent in PEB temperature dependency and excellent in line edge roughness during immersion exposure.

It is the schematic of a two-beam interference exposure experiment apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser 2 Aperture 3 Shutter 4, 5, 6 Reflection mirror 7 Condensing lens 8 Prism 9 Immersion medium 10 Wafer provided with antireflection film and resist film 11 Wafer stage

Claims (13)

(A) It has a structural unit derived from a (meth) acrylic acid ester having a monocyclic or polycyclic alicyclic hydrocarbon structure, has a group that can be decomposed by an acid, and is soluble in an alkali developer by the action of an acid. Increased resin,
(B) a compound that generates an acid upon irradiation with actinic rays or radiation,
(C) Glass transition temperature (Tg) is 110 ° C. or higher, does not have an acid-decomposable group, and contains an alkali-soluble resin having a fluorine atom or a silicon atom, and (D) a solvent. A positive resist composition. The positive resist composition according to claim 1, wherein the component (C) has a fluorine atom. (A) a resin having a group that can be decomposed by an acid and having increased solubility in an alkali developer by the action of the acid;
(B) a compound that generates an acid upon irradiation with actinic rays or radiation,
(C) Glass transition temperature (Tg) is 110 ° C. or higher, does not have an acid-decomposable group and contains an alkali-soluble resin having a fluorine atom and (D) a solvent, Resist composition. The positive resist composition according to claim 3, wherein the component (A) has a structural unit derived from a (meth) acrylic acid ester having a monocyclic or polycyclic alicyclic hydrocarbon structure.   (A) A component has a repeating unit represented by the following general formula (AI), The positive resist composition as described in any one of Claims 1-4 characterized by the above-mentioned.

  In general formula (AI),
  R _b0 Represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.
  A ′ represents a single bond, an ether group, an ester group, a carbonyl group, an alkylene group, or a divalent group obtained by combining these.
  B ₂ Is any one of general formula (Lc) or general formulas (III-1) to (III-5)
Represents a group represented by

  In the general formula (Lc),
  Ra ₁ , Rb ₁ , Rc ₁ , Rd ₁ And Re ₁ Each independently represents a hydrogen atom or an alkyl group.
The
  m and n each independently represents an integer of 0 to 3, and m + n is 2 or more and 6 or less.
  In general formulas (III-1) to (III-5),
  R _1b ~ R _5b Each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylsulfonylimino group or an alkenyl group. R _1b ~ R _5b Two of these may combine to form a ring. Resin (A) has a repeating unit which has group represented by the following general formula (IV), The positive resist composition as described in any one of Claims 1-5 characterized by the above-mentioned.

In general formula (IV),
  R _2c ~ R _4c Each independently represents a hydrogen atom or a hydroxyl group. However, R _2c ~ R _4c At least one of them represents a hydroxyl group. Resin (A) does not have an aromatic group, The positive resist composition as described in any one of Claims 1-6 characterized by the above-mentioned. (C) Content of resin of component is 0.1 mass%-5 mass% of the mass of resin of (A) component, The positive as described in any one of Claims 1-7 characterized by the above-mentioned. Type resist composition. The positive resist composition according to claim 1, wherein the resin of component (C) has a carboxylic acid group or a fluorinated alcohol group as an alkali-soluble group. The positive resist composition according to claim 1, wherein the positive resist composition is used in a resist pattern forming method including a step of immersion exposure. The resist film formed with the positive resist composition as described in any one of Claims 1-9. The pattern formation method characterized by including the process of exposing and developing the resist film of Claim 11 . The pattern forming method according to claim 12 , wherein the resist film is exposed through an immersion medium.

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