JP4866688B2 - Positive resist composition, resin used for positive resist composition, compound used for synthesis of resin, and pattern forming method using positive resist composition - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention is used for 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 a lithography process for other photo applications, and the positive resist composition. The present invention relates to a resin, a compound used for synthesizing the resin, and a pattern forming method using the positive resist composition. In particular, a positive resist composition suitable for exposure with an immersion type projection exposure apparatus using far-ultraviolet light having a wavelength of 300 nm or less as a light source, a resin used in the positive resist composition, and used for synthesis of the resin The present invention relates to a compound and a pattern forming method using the positive resist composition.

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. These 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 liquid”) is filled between a projection lens and a sample is known.
This “immersion effect” means that when λ ₀ is the wavelength of the exposure light in the air, n is the refractive index of the immersion liquid 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 the transfer of a fine image pattern of a semiconductor element are introduced in Patent Document 1 (Japanese Patent Laid-Open No. 57-153433), Patent Document 2 (Japanese Patent Laid-Open No. 7-220990), and the like. Yes.
Recent progress in immersion exposure technology is described in Non-Patent Document 1 (SPIE Proc 4688, 11 (2002)), Non-Patent Document 2 (J. Vac. Sci. Tecnol. B 17 (1999)), Non-Patent Document 3 (SPIE Proc 3999, 2 (2000)), Patent Document 3 (Japanese Patent Laid-Open No. 10-303114), and the like. In the case of using an ArF excimer laser as a light source, pure water (refractive index of 1.44 at 193 nm) is considered to be most promising as an immersion liquid 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.
Although the resist for ArF excimer laser (wavelength: 193 nm) using this chemical amplification mechanism is becoming mainstream at present, the resist profile change due to the placement between exposure and PEB is not sufficiently suppressed, and improvement has been desired. .

In addition, when a chemically amplified resist is applied to immersion exposure, the resist layer comes into contact with the immersion liquid at the time of exposure, so that the resist layer is altered and components that adversely affect the immersion liquid are leached from the resist layer. Has been pointed out. Patent Document 4 (International Publication WO 2004-068242 Pamphlet) describes an example in which resist performance changes by immersing a resist for ArF exposure in water before and after exposure, and points to a problem in immersion exposure. .
In the immersion exposure process, when exposure is performed using a scanning immersion exposure machine, the exposure speed decreases unless the immersion liquid moves following the movement of the lens. Concerned about giving. In the case where the immersion liquid is water, it is desirable that the resist film be hydrophobic so that water followability is better.

JP-A-57-153433 JP-A-7-220990 JP-A-10-303114 International Publication WO 2004-068242 Pamphlet Proc. SPIE, 2002, Vol. 4688, p. 11 J.Vac.Sci.Tecnol.B 17 (1999) Proc. SPIE, 2000, Vol. 3999, p. 2

  An object of the present invention is to provide a positive resist composition which has little profile deterioration not only in normal exposure (dry exposure) but also in immersion exposure, and has good followability to immersion liquid during immersion exposure. Another object is to provide a resin used in the positive resist composition, a compound used in the synthesis of the resin, and a pattern forming method using the positive resist composition.

式（Ｃ−Ｉ）〜（Ｃ-ＩＩＩ）中、
Ｒ _１ は、各々独立に水素原子またはメチル基を表す。
Ｒ _２ は、各々独立に２つ以上の−ＣＨ _３ 部分構造を有する炭化水素基を表す。
Ｐ _１ は、単結合、またはアルキレン、エーテル、またはそれらを２つ以上有する連結基を表す。
Ｐ _２ は、−Ｏ−、−ＮＲ−（Ｒは水素原子またはアルキル）、−ＮＨＳＯ _２ −から選ばれる連結基を表す。
ｘは０〜１００、ｙは０〜１００、ｚは０〜１００を表す。但し、８０≦ｘ＋ｙ＋ｚ≦１００を満たす。
ｎは１〜４の整数を表す。
樹脂Ａ〜Ｃは、それぞれ、下記に示す繰り返し単位からなる樹脂である。

＜２＞ 一般式（Ｃ-ＩＩＩ）で表される繰り返し単位において、Ｐ _２ が酸素原子であり、Ｐ _２ としての酸素原子に直結する、Ｒ _２ としての炭化水素基における炭素原子が１級又は２級である上記＜１＞に記載のポジ型レジスト組成物。
＜３＞ 樹脂（Ｃ）の添加量が０．１〜５質量％である上記＜１＞又は＜２＞に記載のポジ型レジスト組成物。
＜４＞ 樹脂（Ｃ）が、下記の（Ｃ−１）〜（Ｃ−４）から選ばれるいずれかの樹脂である上記＜１＞〜＜３＞のいずれか一項に記載のポジ型レジスト組成物。
（Ｃ−１）酸分解性基を含み、アルカリ可溶性基を含まない樹脂。
（Ｃ−２）酸分解性基およびアルカリ可溶性基を含まない樹脂。
（Ｃ−３）酸分解性基は含まず、アルカリ可溶性基を含む樹脂。
（Ｃ−４）酸分解性基およびアルカリ可溶性基を含む樹脂。
＜５＞ 樹脂（Ｃ）が、（Ｃ−１）〜（Ｃ−３）から選ばれるいずれかの樹脂である上記＜４＞に記載のポジ型レジスト組成物。
＜６＞ 樹脂（Ｃ）が、炭素原子と水素原子と酸素原子と窒素原子と硫黄原子以外の元素を有さない上記＜１＞〜＜５＞のいずれか一項に記載のポジ型レジスト組成物。
＜７＞ 樹脂（Ａ）が、５〜７員環ラクトン構造に、ビシクロ構造又はスピロ構造を形成する形で他の環構造が縮環しているラクトン構造を有する上記＜１＞〜＜６＞のいずれか一項に記載のポジ型レジスト組成物。
＜８＞ 製膜した際の水の膜に対する後退接触角が７０°以上である上記＜１＞〜＜７＞のいずれか一項に記載のポジ型レジスト組成物。
＜９＞ 上記＜１＞〜＜８＞のいずれか一項に記載のレジスト組成物により形成されたレジスト膜。
＜１０＞ 上記＜９＞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。
＜１１＞ 上記＜９＞に記載のレジスト膜を、液浸露光、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。
本発明は、上記＜１＞〜＜１１＞に記載の構成を有するが、以下、他の事項についても記載している。 The present invention is a positive resist composition having the following constitution, a resin used in the positive resist composition, a compound used in the synthesis of the resin, and a pattern forming method using the positive resist composition. The above object of the present invention is achieved.
<1> (A) a resin whose solubility in an alkaline developer is increased by the action of an acid;
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) Resin having 80 to 100 mol% of a repeating unit selected from the following general formulas (CI) to (C-III) in terms of the corresponding monomer (excluding resins A to C shown below) ,
(D) Solvent
A positive resist composition comprising:

In the formulas (CI) to (C-III),
R ₁ each independently represents a hydrogen atom or a methyl group.
R ₂ independently represents a hydrocarbon group having two or more —CH ₃ partial structures.
P ₁ represents a single bond or alkylene, ether, or a linking group having two or more thereof.
P ₂ represents a linking group selected from —O—, —NR— (R is a hydrogen atom or alkyl), and —NHSO ₂ —.
x represents 0 to 100, y represents 0 to 100, and z represents 0 to 100. However, 80 ≦ x + y + z ≦ 100 is satisfied.
n represents an integer of 1 to 4.
Resins A to C are resins composed of repeating units shown below.

<2> In the repeating unit represented by the general formula (C-III), P ₂ is an oxygen atom, and the carbon atom in the hydrocarbon group as R ₂ directly connected to the oxygen atom as P ₂ is primary or The positive resist composition according to <1>, which is secondary.
<3> The positive resist composition according to <1> or <2>, wherein the addition amount of the resin (C) is 0.1 to 5% by mass.
<4> The positive resist according to any one of <1> to <3>, wherein the resin (C) is any resin selected from the following (C-1) to (C-4): Composition.
(C-1) A resin containing an acid-decomposable group and no alkali-soluble group.
(C-2) A resin containing no acid-decomposable group or alkali-soluble group.
(C-3) Resin which does not contain acid-decomposable group and contains alkali-soluble group.
(C-4) A resin containing an acid-decomposable group and an alkali-soluble group.
<5> The positive resist composition according to <4>, wherein the resin (C) is any resin selected from (C-1) to (C-3).
<6> The positive resist composition according to any one of <1> to <5>, wherein the resin (C) does not have an element other than a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. object.
<7> The above <1> to <6>, wherein the resin (A) has a lactone structure in which another ring structure is condensed in a form forming a bicyclo structure or a spiro structure on a 5- to 7-membered ring lactone structure. The positive resist composition as described in any one of the above.
<8> The positive resist composition according to any one of <1> to <7>, wherein a receding contact angle with respect to the water film when the film is formed is 70 ° or more.
<9> A resist film formed from the resist composition according to any one of <1> to <8>.
<10> A pattern forming method comprising a step of exposing and developing the resist film according to <9>.
<11> A pattern forming method comprising the steps of immersion exposure and development of the resist film according to <9>.
Although this invention has the structure as described in said <1>-<11>, below, other matters are also described.

式（Ｃ−Ｉ）〜（Ｃ-ＩＩＩ）中、
Ｒ_１は、各々独立に水素原子またはメチル基を表す。
Ｒ_２は、各々独立に２つ以上の−ＣＨ_３部分構造を有する炭化水素基を表す。
Ｐ_１は、単結合、またはアルキレン、エーテル、またはそれらを２つ以上有する連結基を表す。
Ｐ_２は、−Ｏ−、−ＮＲ−（Ｒは水素原子またはアルキル）、−ＮＨＳＯ_２−から選ばれる連結基を表す。
ｘは０〜１００、ｙは０〜１００、ｚは０〜１００を表す。但し、８０≦ｘ＋ｙ＋ｚ≦１００を満たす。
ｎは１〜４の整数を表す。
（２）
樹脂（Ｃ）の添加量が０．１〜５質量％である上記（１）のポジ型レジスト組成物。
（３）
樹脂（Ｃ）が、下記の（Ｃ−１）〜（Ｃ−４）から選ばれるいずれかの樹脂である上記（１）または（２）のポジ型レジスト組成物。
（Ｃ−１）酸分解性基を含み、アルカリ可溶性基を含まない樹脂。
（Ｃ−２）酸分解性基およびアルカリ可溶性基を含まない樹脂。
（Ｃ−３）酸分解性基は含まず、アルカリ可溶性基を含む樹脂。
（Ｃ−４）酸分解性基およびアルカリ可溶性基を含む樹脂。
（４）
樹脂（Ｃ）が、炭素原子と水素原子と酸素原子と窒素原子と硫黄原子以外の元素を有さない上記（１）〜（３）のいずれかのポジ型レジスト組成物。
（５）
製膜した際の水の膜に対する後退接触角が７０°以上である上記（１）〜（４）のいずれかのポジ型レジスト組成物。
（６）
上記（１）〜（５）のレジスト組成物によりレジスト膜を形成し、液浸露光、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。 (1)
(A) a resin whose solubility in an alkaline developer is increased by the action of an acid;
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) a resin having 80 to 100 mol% of a repeating unit selected from the following general formulas (CI) to (C-III) in terms of a corresponding monomer,
(D) A positive resist composition containing a solvent.

In the formulas (CI) to (C-III),
R ₁ each independently represents a hydrogen atom or a methyl group.
R ₂ independently represents a hydrocarbon group having two or more —CH ₃ partial structures.
P ₁ represents a single bond or alkylene, ether, or a linking group having two or more thereof.
P ₂ represents a linking group selected from —O—, —NR— (R is a hydrogen atom or alkyl), and —NHSO ₂ —.
x represents 0 to 100, y represents 0 to 100, and z represents 0 to 100. However, 80 ≦ x + y + z ≦ 100 is satisfied.
n represents an integer of 1 to 4.
(2)
The positive resist composition according to the above (1), wherein the addition amount of the resin (C) is 0.1 to 5% by mass.
(3)
The positive resist composition according to the above (1) or (2), wherein the resin (C) is any resin selected from the following (C-1) to (C-4).
(C-1) A resin containing an acid-decomposable group and no alkali-soluble group.
(C-2) A resin containing no acid-decomposable group or alkali-soluble group.
(C-3) Resin which does not contain acid-decomposable group and contains alkali-soluble group.
(C-4) A resin containing an acid-decomposable group and an alkali-soluble group.
(4)
The positive resist composition according to any one of the above (1) to (3), wherein the resin (C) does not have an element other than a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom.
(5)
The positive resist composition according to any one of the above (1) to (4), wherein a receding contact angle with respect to a water film upon film formation is 70 ° or more.
(6)
A pattern forming method comprising the steps of: forming a resist film from the resist compositions (1) to (5) above;

  The preferred embodiments of the present invention will be further described below.

(7)
The positive resist composition according to any one of the above (1) to (5), wherein the resin (C) has a weight average molecular weight of 2000 to 20000.
(8)
The positive resist composition according to any one of the above (1) to (5) and (7), wherein the resin (A) has a repeating unit having an alicyclic hydrocarbon group substituted with a hydroxyl group or a cyano group.
(9)
Resin (A) is at least a (meth) acrylate-based repeating unit having a lactone ring, a (meth) acrylate-based repeating unit having an organic group substituted with at least one of a hydroxyl group and a cyano group, and an acid-decomposable group The positive resist composition according to any one of (1) to (5), (7) and (8) above, which is a copolymer having three types of repeating units of (meth) acrylate-based repeating units having .
(10)
(1) to (5) and (7) to (7) above, wherein the compound (B) is a sulfonium salt compound that generates an aliphatic sulfonic acid having a fluorine atom or a benzenesulfonic acid having a fluorine atom upon irradiation with actinic rays or radiation. The positive resist composition according to any one of (9).
(11)
The positive resist composition according to any one of the above (1) to (5) and (7) to (10), wherein the solvent (D) is a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.

  According to the present invention, there is little deterioration in profile and line edge roughness even in immersion exposure, and good followability to immersion liquid in immersion exposure, which is suitable for immersion exposure. And a pattern forming method using the positive resist composition.

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 whose solubility in an alkaline developer is increased by the action of an acid The resin used in the positive resist composition of the present invention is a resin that decomposes by the action of an acid and increases its solubility in an alkaline developer. Resin having a group (hereinafter also referred to as “acid-decomposable group”) that decomposes by the action of an acid to generate an alkali-soluble group (hereinafter also referred to as “acid-decomposable group”) in the main chain or side chain of Or “resin (A)”).
Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) (alkylcarbonyl) Imido group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) methylene group A group having
Preferred alkali-soluble groups include carboxylic acid groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.
A preferred group as an acid-decomposable group (acid-decomposable group) is a group obtained by substituting the hydrogen atom of these alkali-soluble groups with a group capable of leaving with an acid.
Examples of the group leaving with 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.

  When irradiating the positive resist composition of the present invention with ArF excimer laser light, the acid-decomposable resin is decomposed by the action of an acid having a monocyclic or polycyclic alicyclic hydrocarbon structure, and an alkaline developer. It is preferable that it is resin which the solubility with respect to increases.

  As a resin that has a monocyclic or polycyclic alicyclic hydrocarbon structure, decomposes by the action of an acid, and increases its solubility in an alkaline developer (hereinafter also referred to as “alicyclic hydrocarbon-based acid-decomposable resin”) , At least selected from the group consisting of repeating units having a partial structure containing an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pV) and repeating units represented by the following general formula (II-AB) It is preferable that it is resin containing 1 type.

In general formulas (pI) to (pV),
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 is an atom necessary for forming a cycloalkyl group together with a carbon atom. Represents a group.
R _{12 to} R ₁₆ each independently represents a linear or branched alkyl group or cycloalkyl group having 1 to 4 carbon atoms. However, at least one of R _{12 to} R ₁₄ , or any of R ₁₅ and R ₁₆ represents a cycloalkyl 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 a cycloalkyl group. However, at least one of R _{17 to} R ₂₁ represents a cycloalkyl group. Further, either R ₁₉ or R ₂₁ represents a linear or branched alkyl group or cycloalkyl 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 a cycloalkyl group. However, at least one of R _{22 to} R ₂₅ represents a cycloalkyl group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

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).

  The general formula (II-AB) is more preferably the following general formula (II-AB1) or general formula (II-AB2).

In the formulas (II-AB1) and (II-AB2),
R ₁₃ ′ to R ₁₆ ′ each independently represents a hydrogen atom, a halogen atom, 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 cycloalkyl group. At least two of R ₁₃ ′ to R ₁₆ ′ may combine to form a ring.
Here, R ₅ represents an alkyl group, a cycloalkyl group, or a group having a lactone structure.
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 a group having a lactone structure.
R ₆ represents an alkyl group or a cycloalkyl group.
n represents 0 or 1.

In the general formulas (pI) to (pV), the alkyl group in R _{12 to} R ₂₅ represents a linear or branched alkyl group having 1 to 4 carbon atoms.

The cycloalkyl group in R _{11 to} R ₂₅ or the cycloalkyl group formed by Z and the 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 cycloalkyl groups may have a substituent.

  Preferred cycloalkyl groups include adamantyl group, noradamantyl group, decalin residue, tricyclodecanyl group, tetracyclododecanyl group, norbornyl group, cedrol group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, A cyclodecanyl group and a cyclododecanyl group can be mentioned. More preferable examples include an adamantyl group, norbornyl group, cyclohexyl group, cyclopentyl group, tetracyclododecanyl group, and tricyclodecanyl group.

  As further substituents of these alkyl groups and cycloalkyl groups, alkyl groups (1 to 4 carbon atoms), halogen atoms, hydroxyl groups, alkoxy groups (1 to 4 carbon atoms), carboxyl groups, alkoxycarbonyl groups (carbon numbers) 2-6). 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 (pV) 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 structure in which a hydrogen atom of a carboxylic acid group, a sulfonic acid group, a phenol group, or a thiol group is substituted with a structure represented by the general formulas (pI) to (pV), preferably a carboxylic acid Group, a hydrogen atom of a sulfonic acid group is substituted with a structure represented by general formulas (pI) to (pV).

  As the repeating unit having an alkali-soluble group protected by the structure represented by the general formulas (pI) to (pV), a repeating unit represented by the following general formula (pA) is preferable.

Here, R represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms. A plurality of R may be the same or different.
A represents a single bond, 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. A single bond and an alkyl ester group are preferable.
Rp ₁ represents any group of the above formulas (pI) to (pV).

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

  Hereinafter, although the specific example of the repeating unit shown by general formula (pA) is shown, this invention is not limited to this.

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.

Examples of the alkyl group in R ₁₁ ′ and R ₁₂ ′ include a linear or branched alkyl group having 1 to 10 carbon atoms.

  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 those similar to the alicyclic hydrocarbon groups of R _{12 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-AB1) or (II-AB2).

  In the alicyclic hydrocarbon-based acid-decomposable resin according to the present invention, the group decomposed by the action of an acid has a partial structure containing the alicyclic hydrocarbon represented by the general formula (pI) to the general formula (pV). It can be contained in at least one kind of repeating unit among the repeating unit having, the repeating unit represented by formula (II-AB), and the repeating unit of the copolymerization component described later.

Various substituents of R ₁₃ ′ to R ₁₆ ′ in the general formula (II-AB1) or the general formula (II-AB2) are atomic groups for forming an alicyclic structure in the general formula (II-AB). It can also be a substituent of the atomic group Z for forming a bridged alicyclic structure.

  Specific examples of the repeating unit represented by the general formula (II-AB1) or (II-AB2) include the following specific examples, but the present invention is not limited to these specific examples.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention preferably has a lactone group. As the lactone group, any group can be used as long as it contains a lactone structure, but it is preferably a group containing a 5- to 7-membered ring lactone structure, and a bicyclo structure in the 5- to 7-membered ring lactone structure, Those in which other ring structures are condensed to form a spiro structure are preferred. It is more preferable to have a repeating unit having a group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). Further, a group having a lactone structure may be directly bonded to the main chain. Preferred lactone structures are groups represented by general formulas (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), By using a specific lactone structure, line edge roughness and development defects are improved.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. n2 represents an integer of 0 to 4. When n2 is 2 or more, a plurality of Rb ₂ may be the same or different, and a plurality of Rb ₂ may be bonded to form a ring.

As the repeating unit having a group having a lactone structure represented by any of the general formulas (LC1-1) to (LC1-16), R _{13 in the} above general formula (II-AB1) or (II-AB2) may be used. Wherein at least one of 'to R ₁₆ ' has a group represented by the general formulas (LC1-1) to (LC1-16) (for example, R _{5 of} -COOR ₅ is represented by the general formulas (LC1-1) to (LC1) -16) or 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.
Preferable substituents that the alkyl group for R _b0 may have include a hydroxyl group and a halogen atom.
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 or a methyl group.
A _b is a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group obtained by combining these. Represents. A linking group represented by a single bond or —Ab ₁ —CO ₂ — is preferable.
Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group.
V represents a group represented by any one of the general formulas (LC1-1) to (LC1-16).

  The repeating unit having a lactone structure usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

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

The alicyclic hydrocarbon-based acid-decomposable resin of the present invention has a repeating unit containing an organic group having a polar group, particularly a repeating unit having an alicyclic hydrocarbon structure substituted with a polar group. preferable. This improves the substrate adhesion and developer compatibility. The alicyclic hydrocarbon structure of the alicyclic hydrocarbon structure substituted with a polar group is preferably an adamantyl group, a diamantyl group, or a norbornane group. The polar group is preferably a hydroxyl group or a cyano group.
As the alicyclic hydrocarbon structure substituted with a polar group, partial structures represented by the following general formulas (VIIa) to (VIId) are preferable.

In general formulas (VIIa) to (VIIc),
R _{2c to} R _4c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R _{2c to} R _4c represents a hydroxyl group or a cyano group. Preferably, one or two of R _{2c to} R _4c are a hydroxyl group and the rest are hydrogen atoms.
In general formula (VIIa), it is more preferable that two members out of R _{2c to} R _4c are a hydroxyl group and the remaining is a hydrogen atom.

As the repeating unit having a group represented by the general formulas (VIIa) to (VIId), at least one of R ₁₃ ′ to R ₁₆ ′ in the general formula (II-AB1) or (II-AB2) is the above. has a group represented by the general formula (VII) (e.g., represents a group R ₅ in -COOR ₅ is a represented by the general formula (VIIa) ~ (VIId)) , or the following general formula (AIIa) ~ ( A repeating unit represented by AId) can be mentioned.

In general formulas (AIIa) to (AIId),
R _1c represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.
R _2c to R _4c have the same meanings as R _2c to R _4c in formulas (VIIa) ~ (VIIc).

  Although the specific example of the repeating unit which has a structure represented by general formula (AIIa)-(AIId) is given to the following, this invention is not limited to these.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention may have a repeating unit represented by the following general formula (VIII).

In the above general formula (VIII),
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 of R ₄₁ and R ₄₂ may be substituted with a halogen atom (preferably a fluorine atom) or the like.

  Examples of the repeating unit represented by the general formula (VIII) include the following specific examples, but the present invention is not limited thereto.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention preferably has a repeating unit having an alkali-soluble group, and more preferably has a repeating unit having a carboxyl group. By containing this, the resolution in contact hole applications increases. The repeating unit having a carboxyl group includes a repeating unit in which a carboxyl group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a carboxyl group in the main chain of the resin through a linking group. Either a repeating unit that is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is introduced at the end of the polymer chain at the time of polymerization, and the linking group is a monocyclic or polycyclic hydrocarbon. You may have a structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention may further have a repeating unit having 1 to 3 groups represented by the general formula (F1). This improves line edge roughness performance.

In general formula (F1),
R _{50 to} R ₅₅ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{50 to} R ₅₅ represents a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.
Rx represents a hydrogen atom or an organic group (preferably an acid-decomposable protecting group, an alkyl group, a cycloalkyl group, an acyl group, or an alkoxycarbonyl group).

The alkyl group of R _{50 to} R ₅₅ may be substituted with a halogen atom such as a fluorine atom, a cyano group, etc., preferably an alkyl group having 1 to 3 carbon atoms, such as a methyl group or a trifluoromethyl group. be able to.
R _{50 to} R ₅₅ are preferably all fluorine atoms.

  Examples of the organic group represented by Rx include an acid-decomposable protective group and an optionally substituted alkyl group, cycloalkyl group, acyl group, alkylcarbonyl group, alkoxycarbonyl group, alkoxycarbonylmethyl group, alkoxymethyl group. , 1-alkoxyethyl group is preferable.

  The repeating unit having a group represented by the general formula (F1) is preferably a repeating unit represented by the following general formula (F2).

In general formula (F2),
Rx represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. Preferable substituents that the alkyl group of Rx may have include a hydroxyl group and a halogen atom.
Fa represents a single bond or a linear or branched alkylene group (preferably a single bond).
Fb represents a monocyclic or polycyclic hydrocarbon group.
Fc represents a single bond or a linear or branched alkylene group (preferably a single bond or a methylene group).
F ₁ represents a group represented by the general formula (F1).
P ₁ represents a 1 to 3.
The cyclic hydrocarbon group for Fb is preferably a cyclopentyl group, a cyclohexyl group, or a norbornyl group.

  Specific examples of the repeating unit having a group represented by the general formula (F1) are shown below, but the present invention is not limited thereto.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention may further contain a repeating unit having an alicyclic hydrocarbon structure and not exhibiting acid decomposability. This can reduce the elution of low molecular components from the resist film to the immersion liquid during immersion exposure. Examples of such a repeating unit include 1-adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and cyclohexyl (meth) acrylate.

  In addition to the above repeating structural units, the alicyclic hydrocarbon-based acid-decomposable resin of the present invention has a dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and resolving power that is a general necessary characteristic of a resist. Various repeating structural units can be contained for the purpose of adjusting heat resistance, sensitivity, and the like.

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

  As a result, performance required for the alicyclic hydrocarbon-based acid-decomposable resin, in particular, (1) solubility in coating solvent, (2) film-forming property (glass transition temperature), (3) alkali developability, (4 Fine adjustments such as () film slippage (selection of hydrophilicity / hydrophobicity, alkali-soluble group), (5) adhesion of unexposed part to substrate, (6) dry etching resistance, etc. are possible.

  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 alicyclic hydrocarbon-based acid-decomposable resins, the molar ratio of each repeating structural unit is the resist's dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and resolution that is a general required performance of resists. In order to adjust heat resistance, sensitivity, etc., it is set appropriately.

Preferred embodiments of the alicyclic hydrocarbon-based acid-decomposable resin of the present invention include the following.
(1) What contains the repeating unit which has a partial structure containing the alicyclic hydrocarbon represented by said general formula (pI)-(pV) (side chain type).
Preferably those containing (meth) acrylate repeating units having a structure of (pI) to (pV).
(2) One containing a repeating unit represented by the general formula (II-AB) (main chain type).
However, in (2), for example, the following can be further mentioned.
(3) A repeating unit represented by the general formula (II-AB), a maleic anhydride derivative and a (meth) acrylate structure (hybrid type).

  In the alicyclic hydrocarbon-based acid-decomposable resin, the content of the repeating unit having an acid-decomposable group is preferably 10 to 60 mol%, more preferably 20 to 50 mol%, still more preferably 25 in all repeating structural units. -40 mol%.

  In the acid-decomposable resin, the content of the repeating unit having an acid-decomposable group is preferably 10 to 60 mol%, more preferably 20 to 50 mol%, still more preferably 25 to 40 mol% in all repeating structural units. is there.

  In the alicyclic hydrocarbon-based acid-decomposable resin, the content of the repeating unit having a partial structure containing the alicyclic hydrocarbon represented by the general formulas (pI) to (pV) is 20 to 70 in all the repeating structural units. The mol% is preferable, more preferably 20 to 50 mol%, still more preferably 25 to 40 mol%.

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

In the acid-decomposable resin, the content of the repeating unit having a lactone ring is preferably 10 to 70 mol%, more preferably 20 to 60 mol%, still more preferably 25 to 40 mol% in all repeating structural units.
In the acid-decomposable resin, the content of the repeating unit having an organic group having a polar group is preferably 1 to 40 mol%, more preferably 5 to 30 mol%, still more preferably 5 to 20 mol in all repeating structural units. %.

  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. ) To 99 p% with respect to the total number of moles of the repeating structural unit having a partial structure containing an alicyclic hydrocarbon represented by (pV) and the repeating unit represented by the general formula (II-AB). The following is preferable, More preferably, it is 90 mol% or less, More preferably, it is 80 mol% or less.

  When the positive resist 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 alicyclic hydrocarbon-based acid-decomposable resin used in the present invention is preferably one in which all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units may be methacrylate repeating units, all of the repeating units may be acrylate repeating units, and all of the repeating units may be any mixture of methacrylate repeating units / acrylate repeating units, It is preferable that the acrylate repeating unit is 50 mol% or less of the entire repeating unit.

  The alicyclic hydrocarbon-based acid-decomposable resin includes at least a (meth) acrylate-based repeating unit having a lactone ring, a (meth) acrylate-based repeating unit having an organic group substituted with at least one of a hydroxyl group and a cyano group, and A copolymer having three types of repeating units of a (meth) acrylate-based repeating unit having an acid-decomposable group is preferable.

  Preferably, 20 to 50 mol% of repeating units having a partial structure containing an alicyclic hydrocarbon represented by general formulas (pI) to (pV), 20 to 50 mol% of repeating units having a lactone structure, substituted with a polar group It is a ternary copolymer containing 5 to 30% of repeating units having an alicyclic hydrocarbon structure, or a quaternary copolymer containing 0 to 20% of other repeating units.

  Particularly preferable resins include 20 to 50 mol% of repeating units having an acid-decomposable group represented by the following general formulas (ARA-1) to (ARA-7), and the following general formulas (ARL-1) to (ARL- 7) Repeating unit having an alicyclic hydrocarbon structure substituted with a polar group represented by the following general formulas (ARH-1) to (ARH-3): 20-50 mol% having a lactone group represented by 7) A ternary copolymer containing 5 to 30 mol% of units, or a carboxyl group, or a repeating unit having a structure represented by the general formula (F1), having an alicyclic hydrocarbon structure and not exhibiting acid decomposability It is a quaternary copolymer containing 5 to 20 mol% of repeating units.

(In the formula, Rxy1 represents a hydrogen atom or a methyl group, and Rxa1 and Rxb1 each represents a methyl group or an ethyl group.
)

  The alicyclic hydrocarbon-based acid-decomposable resin used in the present invention can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and heating is performed, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as that used in the resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.

The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. 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 5 to 50% by mass, preferably 10 to 30% by mass.
The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

The weight average molecular weight of the resin according to the present invention is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, and most preferably 5,000 to 15 in terms of polystyrene by GPC method. , 000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, developability is deteriorated, and viscosity is increased, resulting in deterioration of film forming property. Can be prevented.
The degree of dispersion (molecular weight distribution) is usually 1 to 5, preferably 1 to 3, more preferably 1.2 to 3.0, particularly preferably 1.2 to 2.0. . The smaller the degree of dispersion, the better the resolution and the resist shape, the smoother the side wall of the resist pattern, and the better the roughness.

In the positive resist composition of the present invention, the blending amount of all the resins according to the present invention in the entire composition is preferably 50 to 99.9% by mass, more preferably 60 to 99.0% by mass in the total solid content. %.
In the present invention, the resins may be used alone or in combination.

(B) Compound that generates acid upon irradiation with actinic ray or radiation The positive resist composition of the present invention is a compound that generates acid upon irradiation with actinic ray or radiation ("photoacid generator" or "component (B)") (Also called).
Examples of such photoacid generators include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, actinic rays used in microresists, etc. Known compounds that generate an acid upon irradiation with radiation and mixtures 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.

  Among the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, compounds represented by the following general formulas (ZI), (ZII), and (ZIII) can be exemplified. The compound represented by ZI) is particularly preferred from the viewpoints of sensitivity and storage stability.

In the above general formula (ZI), R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, preferably sulfonate anion, carboxylate anion, bis (alkylsulfonyl) amide anion, tris (alkylsulfonyl) methide anion, BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ^{− and the} like. Preferably, it is an organic anion containing a carbon atom.

  Preferable organic anions include organic anions represented by the following formulas AN1 to AN4. From the viewpoint of sensitivity, organic anions represented by AN1, AN3, and AN4 are particularly preferable.

In the formula, Rc ₁ represents an organic group.
Is raised preferably an optionally substituted alkyl group having a carbon number of 1-30 as an organic group in rc _1, an aryl group or a plurality of these, a single bond, -O -, - CO 2 - , - S _{-, - SO 3 -, -} SO 2 N (Rd 1) - can be exemplified linked group a linking group such as. Rd ₁ represents a hydrogen atom or an alkyl group.
Rc ₃ , Rc ₄ and Rc ₅ represent an organic group. Preferred examples of the organic group for Rc ₃ , Rc ₄ , and Rc ₅ include the same organic groups as those for Rb 1, and most preferably a perfluoroalkyl group having 1 to 4 carbon atoms.
Rc ₃ and Rc ₄ may be bonded to form a ring.
Examples of the group formed by combining Rc ₃ and Rc ₄ include an alkylene group and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group.
The organic group of Rc ₁ and Rc _{3 to} Rc ₅ is most preferably an alkyl group substituted at the _1- position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved. Further, when Rc ₃ and Rc ₄ are bonded to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved.
When Rc ₁ has 5 or more carbon atoms, at least one carbon atom is preferably substituted with a hydrogen atom, and more preferably, the number of hydrogen atoms is larger than that of fluorine atoms. From the viewpoint of ecological toxicity, it is preferable not to have a perfluoroalkyl group having 5 or more carbon atoms.

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 preferable (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, and aryldicycloalkylsulfonium compounds.
The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, more preferably a phenyl group or an indole residue. 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 (for example, 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, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, and particularly preferable. Is an alkyl group having 1 to 4 carbon atoms and 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.

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 containing no 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 linear, it may be either branched, preferably a straight-chain or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group). The alkyl group as R ₂₀₁ to R ₂₀₃ is a straight-chain or branched 2-oxoalkyl group is preferably an alkoxycarbonyl methyl group.
The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably a cyclic 2-oxoalkyl group.
Linear as R ₂₀₁ to R _203, branched or cyclic 2-oxoalkyl group may preferably be a group having a 2-position> C = O in the above-described alkyl or cycloalkyl group.
The alkoxy group in the alkoxycarbonylmethyl group as R ₂₀₁ to R _203, preferably may be mentioned alkoxy groups having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a 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.
Rx and Ry 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 _7c, and R _x and R _y may be bonded to each other to form a ring structure, the ring structure may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond May be included. Examples of the group formed by combining any two or more of R _{1c to} R _7c and R _x and R _y include a butylene group and a pentylene group.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as X ^{− in} formula (ZI).

The alkyl group as R _{1c to} R _7c may be either linear or branched, for example, a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Or a linear or branched alkyl group (for example, a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, or a linear or branched pentyl group).
The cycloalkyl group as R _{1c to} R _7c is preferably a cycloalkyl group having 3 to 8 carbon atoms (for example, a cyclopentyl group or 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 as R _x and R _y include the same alkyl groups as R _{1c to} R _7c . The alkyl group as R _x and R _y is preferably a linear or branched 2-oxoalkyl group or an alkoxycarbonylmethyl group.
The cycloalkyl group as R _x and R _y may be the same as the cycloalkyl group as R _1c to R _7c. The cycloalkyl group as R _x and R _y is preferably a cyclic 2-oxoalkyl group.
Examples of the linear, branched, or cyclic 2-oxoalkyl 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.
Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group.
The alkyl group as R ₂₀₄ to R ₂₀₇ may be linear, it may be either branched, preferably a straight-chain or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group).
The cycloalkyl group as R ₂₀₄ to R ₂₀₇ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
R ₂₀₄ to R ₂₀₇ may have a substituent. 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).

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, compounds represented by the following general formulas (ZIV), (ZV), and (ZVI) can be further exemplified.

In general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₆ represents an alkyl group or an aryl group.
_R207 and _R208 each independently represents an alkyl group, an aryl group, or an electron-withdrawing group.
R ₂₀₇ is preferably an aryl group.
R ₂₀₈ is preferably an electron-withdrawing group, more preferably a cyano group or a fluoroalkyl group.
A represents an alkylene group, an alkenylene group or an arylene group.

As a compound which decomposes | disassembles by irradiation of actinic light or a radiation and generate | occur | produces an acid, More preferably, it is a compound represented by (ZI), Most preferably, it is a compound represented by (ZI-1) and (ZI-3) It is. (ZI-1) in a triarylsulfonium compound all is an aryl group of R ₂₀₁ to R ₂₀₃ is preferably, triphenylsulfonium compound having at least one alkyl group (preferably having from 1 to 10 carbon atoms) is substituted is preferred .

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, examples of particularly preferable compounds are listed below.

A photo-acid generator can be used individually by 1 type or in combination of 2 or more types. When two or more types are used in combination, it is preferable to combine two types of compounds that generate two types of organic acids that differ in the total number of atoms excluding hydrogen atoms by two or more.
The content of the photoacid generator is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 to 7% by mass, based on the total solid content of the positive resist composition. It is.

  The positive resist composition of the present invention contains (C) a resin having 80 to 100 mol% of repeating units selected from the following general formulas (CI) to (C-III).

In the formulas (CI) to (C-III),
R ₁ each independently represents a hydrogen atom or a methyl group.
R ₂ each independently represents a hydrocarbon group having two or more —CH ₃ partial structures (ie, methyl groups).
P ₁ represents a single bond or alkylene, ether, or a linking group having two or more thereof.
P ₂ represents a linking group selected from —O—, —NR— (R is a hydrogen atom or alkyl), and —NHSO ₂ —.
x represents 0 to 100, y represents 0 to 100, and z represents 0 to 100. However, 80 ≦ x + y + z ≦ 100, preferably 85 ≦ x + y + z ≦ 100, more preferably 90 ≦ x + y + z ≦ 100.
n represents an integer of 1 to 4.
These repeating units may be one or a plurality of repeating units may be combined.

Examples of the hydrocarbon group represented by R ₂ in formulas (CI) to (C-III) include an alkyl group, an alkyl-substituted cycloalkyl group, an alkenyl group, an alkyl-substituted cycloalkenyl group, an alkyl-substituted aryl group, and an alkyl-substituted aralkyl group. And an alkyl group and an alkyl-substituted cycloalkyl group are preferable. In the formula (C-III), the carbon atom directly connected to the oxygen atom is preferably primary or secondary.

As the alkyl group for R ₂ , a linear or branched alkyl group having 1 to 20 carbon atoms is preferable, and a branched alkyl group is more preferable. Specific examples of preferable alkyl groups include propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, 3-pentyl, 2-methyl-3-butyl, hexyl, 3- Hexyl group, 2-methyl-3-pentyl group, heptyl group, 3-methyl-4-hexyl group, 3,5-dimethyl-4-pentyl group, octyl group, isooctyl group, 2,4,4-trimethylpentyl group 2-ethylhexyl group, 2,6-dimethylheptyl group, nonyl group, 1,5-dimethyl-3-heptyl group, 2,3,5,7-tetramethyl-4-heptyl group. More preferably, an isobutyl group, a t-butyl group, a 2-methyl-3-butyl group, a 2-methyl-3-pentyl group, a 3-methyl-4-hexyl group, a 3,5-dimethyl-4-pentyl group, 2,4,4-trimethylpentyl group, 2-ethylhexyl group, 2,6-dimethylheptyl group, 1,5-dimethyl-3-heptyl group, 2,3,5,7-tetramethyl-4-heptyl group is there.

The cycloalkyl group represented by R ₂ 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 cycloalkyl groups may have a substituent. Preferred cycloalkyl groups include adamantyl group, noradamantyl group, decalin residue, tricyclodecanyl group, tetracyclododecanyl group, norbornyl group, cedrol group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, A cyclodecanyl group and a cyclododecanyl group can be mentioned. More preferable examples include an adamantyl group, norbornyl group, cyclohexyl group, cyclopentyl group, tetracyclododecanyl group, and tricyclodecanyl group. More preferably, they are a norbornyl group, a cyclopentyl group, and a cyclohexyl group.

As the alkenyl group for R ₂ , a linear or branched alkenyl group having 1 to 20 carbon atoms is preferable, and a branched alkenyl group is more preferable.

The aryl group of R ₂ has no hetero atom. Preferable aryl groups include a phenyl group and a naphthyl group, and preferably a phenyl group.

Specific examples of the hydrocarbon group having two or more methyl groups represented by R _{2 in} the formulas (CI) and (C-II) include an isopropyl group, an isobutyl group, a t-butyl group, and a 3-pentyl group. 2-methyl-3-butyl group, 3-hexyl group, 2,3-dimethyl-2-butyl group, 2-methyl-3-pentyl group, 3-methyl-4-hexyl group, 3,5-dimethyl- 4-pentyl group, isooctyl group, 2,4,4-trimethylpentyl group, 2-ethylhexyl group, 2,6-dimethylheptyl group, 1,5-dimethyl-3-heptyl group, 2,3,5,7- Examples include tetramethyl-4-heptyl group, 3,5-dimethylcyclohexyl group, 4-isopropylcyclohexyl group, 4-tbutylcyclohexyl group, isobornyl group and the like. More preferably, an isobutyl group, a t-butyl group, a 2-methyl-3-butyl group, a 2,3-dimethyl-2-butyl group, a 2-methyl-3-pentyl group, a 3-methyl-4-hexyl group, 3,5-dimethyl-4-pentyl group, 2,4,4-trimethylpentyl group, 2-ethylhexyl group, 2,6-dimethylheptyl group, 1,5-dimethyl-3-heptyl group, 2,3,5 , 7-tetramethyl-4-heptyl group, 3,5-dimethylcyclohexyl group, 4-isopropylcyclohexyl group, 4-tbutylcyclohexyl group and isobornyl group.

Specific examples of the hydrocarbon group having two or more methyl groups of R ₂ in the formula (C-III) include isobutyl group, 3-pentyl group, 2-methyl-3-butyl group, and 3-hexyl group. 2-methyl-3-pentyl group, 3-methyl-4-hexyl group, 3,5-dimethyl-4-pentyl group, isooctyl group, 2,4,4-trimethylpentyl group, 2-ethylhexyl group, 2, 6-dimethylheptyl group, 1,5-dimethyl-3-heptyl group, 2,3,5,7-tetramethyl-4-heptyl group, 3,5-dimethylcyclohexyl group, 4-isopropylcyclohexyl group, 4-t And a butylcyclohexyl group. More preferably, an isobutyl group, 2-methyl-3-butyl group, 2-methyl-3-pentyl group, 3-methyl-4-hexyl group, 3,5-dimethyl-4-pentyl group, 2,4,4 -Trimethylpentyl group, 2-ethylhexyl group, 2,6-dimethylheptyl group, 1,5-dimethyl-3-heptyl group, 2,3,5,7-tetramethyl-4-heptyl group, 3,5-dimethyl A cyclohexyl group, a 4-isopropylcyclohexyl group, and a 4-tbutylcyclohexyl group.

  Preferred specific examples of the formula (CI) are listed below. Note that the present invention is not limited to this.

  Preferred specific examples of the formula (C-II) are given below. Note that the present invention is not limited to this.

式（Ｃ−ＩＩＩ）の好ましい具体例を以下に挙げる。尚、本発明はこれに限定されるものではない。具体例中、Ｒxyは水素原子またはメチル基を表す。

Preferred specific examples of the formula (C-III) are given below. Note that the present invention is not limited to this. In specific examples, Rxy represents a hydrogen atom or a methyl group.

The resin (C) is preferably any resin selected from the following (C-1) to (C-3).
(C-1) A resin containing an acid-decomposable group and no alkali-soluble group.
(C-2) A resin not containing an acid-decomposable group and an alkali-soluble group (a resin that is stable in acid and alkali developers).
(C-3) A resin containing no acid-decomposable group and containing an alkali-soluble group (a resin that is stable with respect to acids and has increased solubility in an alkali developer).
(C-4) A resin containing an acid-decomposable group and an alkali-soluble group.

Of the above, (C-2) is preferable in terms of the followability of the immersion liquid.
(C-1) (C-3) (C-4) having an acid-decomposable group or an alkali-soluble group is preferable because the pattern is hardly deteriorated.
In addition, (C-3) having an alkali-soluble group is preferable because the pattern is hardly deteriorated even when added in a large amount. On the other hand, (C-1) and (C-4) having an acid-decomposable group are preferable in that the balance between the various performances of the resist and the immersion liquid followability is good.

Examples of the acid-decomposable group in (C-1) include the same ones as in the resin (A).
Preferred acid-decomposable groups include —COOC (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C ₆ H ₄ OC (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —COOCH (R ₀₁ ) (OR _{39), - C 6 H 4} OCH (R 01) a (OR _39).
R _{36 to} R ₃₈ and R _{01 to} R ₀₂ are preferably an alkyl group or a cycloalkyl group.
The (C-1) acid-decomposable _{group, -COOC (CH 3) 3,} -COOC (CH 3) 2 (C2H5), - COOC (C2H 5) 3, -COOC (CH 3) 2 CH (CH _{3) 2, -COOC (CH 3} ) 2 C (CH 3) 3, -COOC (CH 3) (C2H 5) (CH 2) 3 CH (CH 3) 2, -COOC (CH 3) (CH = CH2 ) (CH ₂ ) ₃ CH (CH ₃ ) _{2 and the} like.

  Preferred specific examples of (C-1) are given below. In specific examples, Rxy represents a hydrogen atom or a methyl group.

Preferred specific examples of (C-2) are given below. In specific examples, Rxy represents a hydrogen atom or a methyl group.

As the alkali-soluble group of (C-3), —C ₆ H ₄ OH, —COOH, —SO ₃ H, —SO ₂ NHR ₁ (R ₁ is a hydrogen atom or an alkyl group), —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) —), —CONHSO ₂ — and the like. _{Preferably, -C (= O) -CH 2} -C (= O) -, - C (= O) -CHR-C (= O) -, (- C (= O) -CH (C (= O _{)) 2 -, - CONHSO 2} - a, -CONHSO ₂ - is particularly preferred.

  Preferred specific examples of (C-3) are given below. In specific examples, Rxy represents a hydrogen atom or a methyl group.

When the resin (C) has a silicon atom, there is a concern about lens contamination due to outgas at the time of exposure. Therefore, the resin (C) preferably does not have a silicon atom.
In recent years, it is preferable that the resin (C) does not have a fluorine atom because environmental regulations of fluorine compounds have become stricter.
It is preferable that resin (C) does not contain elements other than a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom.

  The resin (C) preferably has a weight average molecular weight (Mw) of 1000 to 10,000. More preferably, it is 2000-20,000, More preferably, it is 2000-10,000. The dispersity (Mw / Mn) is preferably 1.2 to 3.0, and more preferably 1.3 to 2.0.

The resin (C) preferably has no aromatic ring when the exposure wavelength is 193 nm.
The addition amount of the resin (C) in the positive resist composition is preferably 0.1 to 5% by mass, more preferably 0.2 to 3.0%, based on the total solid content of the resist composition. It is mass%, More preferably, it is 0.3-2.0 mass%.

  Resin (C), like acid-decomposable resin (A), naturally has few impurities such as metals, but residual monomers and oligomer components are not more than predetermined values, for example, 0.1% by mass by HPLC. It is preferable that not only the sensitivity, resolution, process stability, pattern shape and the like as a resist can be further improved, but also a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained.

  As the resin (C), various commercially available products can be used, or they can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and heating is performed, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as that used in the resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. The concentration of the reaction is 5 to 50% by mass, preferably 30 to 50% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer. For example, hydrocarbon (pentane, hexane, Aliphatic hydrocarbons such as heptane and octane; Cycloaliphatic hydrocarbons such as cyclohexane and methylcyclohexane; Aromatic hydrocarbons such as benzene, toluene and xylene), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride, etc.) Halogenated aliphatic hydrocarbons; halogenated aromatic hydrocarbons such as chlorobenzene and dichlorobenzene), nitro compounds (nitromethane, nitroethane, etc.), nitriles (acetonitrile, benzonitrile, etc.), ethers (diethyl ether, diisopropyl ether, dimethoxyethane) Chain A Cyclic ethers such as tetrahydrofuran and dioxane), ketones (acetone, methyl ethyl ketone, diisobutyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), carbonates (dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), alcohols ( (Methanol, ethanol, propanol, isopropyl alcohol, butanol, etc.), carboxylic acid (acetic acid, etc.), water, a mixed solvent containing these solvents, and the like.
Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable. In such a solvent containing at least hydrocarbon, the ratio of alcohol (particularly methanol) and other solvent (for example, ester such as ethyl acetate, ethers such as tetrahydrofuran) is, for example, the former / the latter (volume ratio). 25 ° C.) = 10/90 to 99/1, preferably the former / the latter (volume ratio; 25 ° C.) = 30/70 to 98/2, more preferably the former / the latter (volume ratio; 25 ° C.) = 50 / It is about 50 to 97/3.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The nozzle diameter at the time of supplying the polymer solution to the precipitation or reprecipitation solvent (poor solvent) is preferably 4 mmφ or less (for example, 0.2 to 4 mmφ). Moreover, the supply speed (dropping speed) of the polymer solution into the poor solvent is, for example, about 0.1 to 10 m / second, preferably about 0.3 to 5 m / second, as the linear speed.

  The precipitation or reprecipitation operation is preferably performed with stirring. As a stirring blade used for stirring, for example, a desk turbine, a fan turbine (including a paddle), a curved blade turbine, an arrow blade turbine, a fiddler type, a bull margin type, an angled blade fan turbine, a propeller, a multistage type, an anchor type (or Horseshoe type), gate type, double ribbon, screw, etc. can be used. Stirring is preferably further performed for 10 minutes or more, particularly 20 minutes or more after the supply of the polymer solution. When the stirring time is short, the monomer content in the polymer particles may not be sufficiently reduced. Further, the polymer solution and the poor solvent can be mixed and stirred using a line mixer instead of the stirring blade.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated particulate polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent.
That is, after completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e).
The solvent used in the preparation of the resin solution A can be the same solvent as the solvent that dissolves the monomer in the polymerization reaction, and may be the same as or different from the solvent used in the polymerization reaction.

(D) Solvent Examples of the solvent that can be used in preparing the positive resist composition by dissolving the above components include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, Examples thereof include organic solvents such as alkyl alkoxypropionates, cyclic lactones having 4 to 10 carbon atoms, monoketone compounds having 4 to 10 carbon atoms, which may contain a ring, alkylene carbonate, alkyl alkoxyacetates, and alkyl pyruvates. .

Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.
Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.
Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone having 4 to 10 carbon atoms include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ- Caprolactone, γ-octanoic lactone, and α-hydroxy-γ-butyrolactone are preferred.

  Examples of the monoketone compound having 4 to 10 carbon atoms which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4- Methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2 -Hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4 -Heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5- Xen-2-one, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopenta Non, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcyclo Preferred are heptanone and 3-methylcycloheptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.
As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing 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. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.
The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

  The solvent is preferably a mixed solvent of two or more containing propylene glycol monomethyl ether acetate from the viewpoint of coating uniformity.

(E) Basic compound The positive resist composition of the present invention preferably contains (E) a basic compound in order to reduce a change in performance over time from exposure to heating.
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formulas (A) to (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having a carbon number). 6-20), wherein R ²⁰¹ and R ²⁰² may combine with each other to form a ring.

About the said alkyl group, as an alkyl group which has a substituent, a C1-C20 aminoalkyl group, a C1-C20 hydroxyalkyl group, or a C1-C20 cyanoalkyl group is preferable.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
The alkyl groups in these general formulas (A) to (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, and benzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically triphenylsulfonium hydroxide, tris (t-butylphenyl) sulfonium. Examples thereof include hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, and 2-oxopropylthiophenium hydroxide. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.
These basic compounds are used alone or in combination of two or more.

  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) Surfactant The positive resist composition of the present invention preferably further contains (F) a surfactant, and is a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based interface). It is more preferable to contain any one or two or more of an activator and a surfactant having both a fluorine atom and a silicon atom.

When the positive resist composition of the present invention contains the surfactant (F), a resist having good sensitivity and resolution and less adhesion and development defects when using an exposure light source of 250 nm or less, particularly 220 nm or less. A pattern can be given.
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 F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431, 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, 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.

  These surfactants may be used alone or in several combinations.

  (F) The usage-amount of surfactant becomes like this. Preferably it is 0.01-10 mass% with respect to positive resist composition whole quantity (except a solvent), More preferably, it is 0.1-5 mass%.

(G) Carboxylic acid onium salt The positive resist composition in the present invention may contain (G) a carboxylic acid onium salt. Examples of the carboxylic acid onium salt include a carboxylic acid sulfonium salt, a carboxylic acid iodonium salt, and a carboxylic acid ammonium salt. In particular, the (G) carboxylic acid onium salt is preferably an iodonium salt or a sulfonium salt. Furthermore, it is preferable that the carboxylate residue of the (H) carboxylic acid onium salt of the present invention 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 (G) 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 generally 0.1 to 20% by mass, preferably 0.5 to 10% by mass, and more preferably 1%, based on the total solid content of the composition. -7% by mass.

(H) Other Additives The positive resist composition of the present invention further has solubility in dyes, plasticizers, photosensitizers, light absorbers, alkali-soluble resins, dissolution inhibitors and developers as necessary. (For example, a phenol compound having a molecular weight of 1000 or less, an alicyclic compound having a carboxyl group, or an aliphatic compound) and the like can be contained.

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.

(I) Pattern Forming Method The positive resist composition of the present invention is preferably used at a film thickness of 30 to 250 nm, more preferably at a film thickness of 30 to 200 nm, from the viewpoint of improving resolution. preferable. Such a film thickness can be obtained by setting the solid content concentration in the positive resist composition to an appropriate range to give an appropriate viscosity and improving the coating property and film forming property.
The total solid content concentration in the positive resist composition is generally 1 to 10% by mass, more preferably 1 to 8.0% by mass, and still more preferably 1.0 to 6.0% by mass.

  The positive resist composition of the present invention is used by dissolving the above components in a predetermined organic solvent, preferably the mixed solvent, filtering the solution, and then applying the solution on a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon of 0.1 microns or less, more preferably 0.05 microns or less, and still more preferably 0.03 microns or less.

For example, a positive resist composition is coated on a substrate (eg, silicon / silicon dioxide coating) used in the manufacture of precision integrated circuit elements by a suitable coating method such as a spinner or a coater, and dried to form a photosensitive film. Form. In addition, you may coat a well-known antireflection film beforehand.
The photosensitive film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to 1. Far ultraviolet light having a wavelength of 200 nm, specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-ray, electron beam, etc. ArF excimer laser, F ₂ Excimer laser, EUV (13 nm), and electron beam are preferable.

Before forming the resist film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can.

In the development step, an alkaline developer is used as follows. As an alkaline developer of the resist composition, inorganic hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, 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 and the like Alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline developer.
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.
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.
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.

  Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the resist film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred. Further, an overcoat layer may be further provided on the photosensitive film so that the immersion medium and the photosensitive film do not come into direct contact with each other during the immersion exposure. Thereby, the elution of the composition from the photosensitive film to the immersion medium is suppressed, and development defects are reduced.

The immersion liquid used for the immersion exposure will be described below.
The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index 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 liquid, the surface tension of the water is decreased and the surface activity is increased, so that the resist layer on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element can be ignored. 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 MQcm or more, the TOC (organic substance concentration) is desirably 20 ppb or less, and deaeration treatment is desirably performed.
Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. 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.

  When the positive resist composition of the present invention is used as a resist film, the receding contact angle of water with respect to the resist film is preferably 70 ° or more. Here, the receding contact angle is at normal temperature and pressure. The receding contact angle is the receding contact angle when the droplet starts to drop when the resist film is tilted.

Since the resist film is not directly brought into contact with the immersion liquid between the resist film of the positive resist composition of the present invention and the immersion liquid, it is also referred to as an “immersion liquid hardly soluble film” (hereinafter referred to as “top coat”). ) May be provided. The necessary functions for the top coat are suitability for application to the upper layer of the resist, radiation, especially transparency to 193 nm, and poor immersion liquid 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. From the viewpoint of contaminating the optical lens when impurities are eluted from the top coat into the immersion liquid, it is preferable that the residual monomer component of the polymer contained in the top coat is small.

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 top coat and the immersion liquid. In the case of using water as the immersion liquid in an ArF excimer laser (wavelength: 193 nm), the top coat for ArF immersion exposure is preferably close to the refractive index of the immersion liquid. From the viewpoint of making the refractive index close to the immersion liquid, it is preferable to have fluorine atoms in the topcoat. A thin film is more preferable from the viewpoint of transparency and refractive index.

  It is preferred that the top coat is not mixed with the resist and further not mixed with the immersion liquid. From this viewpoint, when the immersion liquid is water, the topcoat solvent is preferably a resist solvent hardly soluble and water-insoluble medium. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be water-soluble or water-insoluble.

  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 Resin (C-1) 4-tbutylstyrene was dissolved in tetrahydrofuran to prepare 50 g of a solution having a solid content concentration of 50%. 0.2 mol% of Wako Pure Chemical Industries, Ltd. polymerization initiator V-65 was added to this solution, and this was stirred under nitrogen atmosphere for 6 hours, and reaction liquid (C-1) was obtained. After completion of the reaction, 15 mL of tetrahydrofuran was added and the reaction solution (C-1) was cooled to room temperature, crystallized in 600 mL of methanol, and the precipitated white powder was collected by filtration to obtain the target resin (C-1). It was collected.
The weight average molecular weight in terms of standard polystyrene determined by GPC measurement was 12000, and the degree of dispersion was 1.8.
Resins (C-2) to (C-10) were synthesized in the same manner as for resin (C-1).
Further, a resin (C-11) was synthesized in the same manner as the resin (C-1) except that hexane was used for crystallization.

Synthesis Example 2: Synthesis of Resin (C-12) 4-tbutylstyrene and acrylic acid (4-tbutylcyclohexyl) were charged at a ratio of 50/50, dissolved in cyclohexanone, and 100 mL of a 20% solid content solution was added. Prepared. To this solution, 5 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added, and this was added dropwise to 10 mL of cyclohexanone 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 (C-12) was obtained. After completion of the reaction, the reaction liquid (C-12) was cooled to room temperature, crystallized in 1 L of methanol, and the precipitated white powder was collected by filtration to recover the target resin (C-12) .
^The polymer composition ratio determined from ¹ H-NMR was 50/50. Moreover, the standard polystyrene conversion weight average molecular weight calculated | required by GPC measurement was 15000, and dispersion degree was 2.1. Resins (C- 13) to (C-16) were synthesized by the same method as for resin (C-12) .
Resins (C-17) to (C-19) were synthesized in the same manner as the resin (C-12) except that hexane was used for crystallization.

The structures of the resins (C-1) to (C-20) are shown below. Further, the molar ratio of repeating units in each resin (corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion are shown.

Synthesis of Resin (A) Resin (A-1) was synthesized according to the method for synthesizing Resin A2 in JP-A-2004-78153. Resin (A-2) was synthesized by the same method as in Example 1 of JP-A-2005-156726.
Resin (A-4) was synthesized by the same method as in Example of JP-A-2004-175981. Resin (A-5) was synthesized in the same manner as in Example 2 of JP-A-2004-124082. Resin (A-7) was synthesized in the same manner as in Example 1 of JP-A-2005-331918. Other resins were synthesized in the same manner as the resin (A-1).
The structure and composition of the acid-decomposable resin (A) used in the examples, the molecular weight, and the like are shown below. The composition indicates the resin structural formula number and the composition ratio (in order from the left in the structural formula).

Examples and Comparative Examples <Resist Preparation>
The components shown in Table 3 below were dissolved in a solvent, and a solution having a solid content of 7% by mass was prepared for each, and this was filtered through a 0.1 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist composition was evaluated by the following method, and the results are shown in Table 3 below. In addition, about each component in Table 3 , the ratio at the time of using multiple is a mass ratio. In Table 3, wt% for the resin C means mass% with respect to the total solid content of the positive resist composition.

[Image performance test]
(Exposure condition (1))
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 composition prepared thereon was applied and baked at 120 ° C. for 60 seconds to form a 200 nm resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser scanner (PAS5500 / 1100, NA0.75, σo / σi = 0.85 / 0.55, manufactured by ASML). Thereafter, heating was performed at 130 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying to obtain a resist pattern.

(Exposure condition (2))
This condition is to form a resist pattern by an immersion exposure method using pure water.
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 composition prepared thereon was applied and baked at 120 ° C. for 60 seconds to form a 200 nm resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser immersion scanner (NA 0.85). Ultra pure water was used as the immersion liquid. Thereafter, heating was performed at 130 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying to obtain a resist pattern.

[Image evaluation]
In (exposure condition 1) and (exposure condition 2), the obtained resist pattern was observed for line edge roughness (LER) and pattern profile using a scanning electron microscope (S-4800 manufactured by Hitachi) .

[Water followability]
The prepared positive resist composition was applied on a silicon wafer and baked at 130 ° C. for 60 seconds to form a 160 nm resist film. Next, as shown in FIG. 1, pure water 2 was filled between the wafer 1 on which the resist film was formed and the quartz glass substrate 3.
In this state, the quartz glass substrate 3 was moved (scanned) in parallel to the surface of the resist-coated substrate 1, and the state of the pure water 2 following it was visually observed. Gradually increase the scan speed of the quartz glass substrate 3 and evaluate the water followability by obtaining the limit scan speed at which the pure water 2 cannot follow the scan speed of the quartz glass substrate 3 and water droplets begin to remain on the receding side. went. As this limit scan speed is larger, water can follow a higher scan speed, and the water followability on the resist film is better.

The symbols in Table 3 are as follows.
The acid generator corresponds to that exemplified above.

N-1: N, N-dibutylaniline N-2: N, N-dihexylaniline N-3: 2,6-diisopropylaniline N-4: tri-n-octylamine N-5: N, N-dihydroxyethyl Aniline N-6: 2,4,5-triphenylimidazole N-7: Tris (methoxyethoxyethyl) amine N-8: 2-phenylbenzimidazole

W-1: Megafuck F176 (manufactured by Dainippon Ink & Chemicals, Inc.)
(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)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
W-5: PF656 (manufactured by OMNOVA, fluorine-based)
W-6: PF6320 (manufactured by OMNOVA, fluorine-based)

SL-1: Cyclohexanone SL-2: Propylene glycol monomethyl ether acetate SL-3: Ethyl lactate SL-4: Propylene glycol monomethyl ether SL-5: γ-butyrolactone SL-6: Propylene carbonate

  As a result, the positive resist composition of the present invention has good line edge roughness performance not only in normal exposure but also in immersion exposure, there is little profile deterioration, and in immersion exposure, It can be seen that the followability to the liquid is also good.

Schematic diagram of water followability evaluation method

Explanation of symbols

1 Wafer on which resist film is formed 2 Pure water 3 Quartz glass substrate

Claims (11)

(A) a resin whose solubility in an alkaline developer is increased by the action of an acid;
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) Resin having 80 to 100 mol% of a repeating unit selected from the following general formulas (CI) to (C-III) in terms of the corresponding monomer (excluding resins A to C shown below) ,
(D) A positive resist composition containing a solvent.

In the formulas (CI) to (C-III),
R ₁ each independently represents a hydrogen atom or a methyl group.
R ₂ independently represents a hydrocarbon group having two or more —CH ₃ partial structures.
P ₁ represents a single bond or alkylene, ether, or a linking group having two or more thereof.
P ₂ represents a linking group selected from —O—, —NR— (R is a hydrogen atom or alkyl), and —NHSO ₂ —.
x represents 0 to 100, y represents 0 to 100, and z represents 0 to 100. However, 80 ≦ x + y + z ≦ 100 is satisfied.
n represents an integer of 1 to 4.
Resins A to C are resins composed of repeating units shown below.

In the repeating unit represented by the general formula (C-III), P ₂ Is an oxygen atom and P ₂ Directly connected to the oxygen atom as ₂ The positive resist composition according to claim 1, wherein a carbon atom in the hydrocarbon group as is primary or secondary. The positive resist composition according to claim 1 or 2 , wherein the addition amount of the resin (C) is 0.1 to 5% by mass. The positive resist composition according to any one of claims 1 to 3, wherein the resin (C) is any resin selected from the following (C-1) to (C-4).
(C-1) A resin containing an acid-decomposable group and no alkali-soluble group.
(C-2) A resin containing no acid-decomposable group or alkali-soluble group.
(C-3) Resin which does not contain acid-decomposable group and contains alkali-soluble group.
(C-4) A resin containing an acid-decomposable group and an alkali-soluble group. The positive resist composition according to claim 4, wherein the resin (C) is any resin selected from (C-1) to (C-3). The positive resist composition according to any one of claims 1 to 5 , wherein the resin (C) does not have an element other than a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. The resin (A) has a lactone structure in which another ring structure is condensed in a form forming a bicyclo structure or a spiro structure in a 5- to 7-membered ring lactone structure. The positive resist composition as described. The positive resist composition according to any one of claims 1 to 7, wherein a receding contact angle with respect to the water film upon film formation is 70 ° or more. The resist film formed with the resist composition as described in any one of Claims 1-8. A pattern forming method comprising the steps of exposing and developing the resist film according to claim 9. A pattern forming method comprising the steps of immersion exposure and development of the resist film according to claim 9 .

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