JP4568662B2 - Positive resist composition and pattern forming method using the same - Google Patents

Description

  The present invention relates to a positive resist composition suitably used in an ultramicrolithography process such as the manufacture of VLSI and high-capacity microchips and other photo-publishing processes. More specifically, the present invention relates to a positive type photoresist that can form a high-definition pattern using electron beam, X-ray, EUV light, etc., and uses electron beam, X-ray, EUV light (wavelength: around 13 nm). The present invention relates to a positive resist composition that can be suitably used for fine processing of semiconductor elements.

  Conventionally, in the manufacturing process of semiconductor devices such as IC and LSI, fine processing by lithography using a photoresist composition has been performed. In recent years, with the high integration of integrated circuits, the formation of ultrafine patterns in the submicron region and the quarter micron region has been required. Along with this, there is a tendency to shorten the exposure wavelength from g-line to i-line and further to KrF excimer laser light. Furthermore, at present, in addition to excimer laser light, lithography using electron beams, X-rays, or EUV light is also being developed.

  In particular, electron beam lithography is positioned as a next-generation or next-generation pattern formation technique, and a positive resist with high sensitivity and high resolution is desired. In the positive resist for electron beams, if high sensitivity is to be pursued, not only lowering of resolution but also deterioration of line edge roughness occurs, and development of a resist satisfying these characteristics is strongly desired. Here, the line edge roughness means that when the pattern is viewed from directly above because the resist pattern and the edge of the substrate interface vary irregularly in the direction perpendicular to the line direction due to the characteristics of the resist. Say that the edge looks uneven. The unevenness is transferred by an etching process using a resist as a mask, and the electrical characteristics are deteriorated, so that the yield is lowered. Particularly in the ultrafine region of 0.25 μm or less, the line edge roughness is an extremely important improvement issue. It is very important how to satisfy high resolution and good line edge roughness at the same time.

  Further, when EUV is used as a light source, the wavelength of light belongs to the extreme ultraviolet region and has high energy, so there is a problem such as a decrease in contrast due to concerted photochemical reactions such as negativity caused by EUV light. Similarly, in lithography using lines and EUV light, it is important to achieve both high sensitivity and high resolution, and these solutions are necessary.

As a resist suitable for a lithography process using such electron beam, X-ray or EUV light, a chemically amplified resist using an acid catalyst reaction is mainly used from the viewpoint of high sensitivity. As a main component, a phenolic polymer (hereinafter abbreviated as a phenolic acid-decomposable resin) that is insoluble or hardly soluble in an alkali developer and becomes soluble in an alkali developer by the action of an acid, and an acid generator A chemically amplified resist composition comprising:
Several resist compositions containing phenolic acid-decomposable resins have been known so far for positive resists for these electron beams, X-rays or EUV (see, for example, Patent Documents 1 to 6).
However, in any combination of these, the present situation is that high resolution and good line edge roughness in the ultrafine region are not satisfied at the same time.

JP 2002-323768 A JP-A-6-41221 Japanese Patent No. 3173368 JP 2000-122291 A JP 2001-114825 A JP 2001-206917 A

  An object of the present invention is to solve the problem of performance improvement technology in microfabrication of a semiconductor element using high energy rays, X-rays, electron beams or EUV light, and has high sensitivity, high resolution, and good line. It is an object of the present invention to provide a positive resist composition that simultaneously satisfies edge roughness.

  As a result of intensive studies, the present inventors have surprisingly found that the subject of the present invention is (A) a specific phenolic acid-decomposable resin and (B) a compound that generates an acid upon irradiation with active light or radiation, ( C) It is achieved by a positive resist composition containing an organic basic compound.

一般式（Ｉ）および（ＩＩ）中、
Ｒ _１ は、水素原子、メチル基、シアノ基、ハロゲン原子又はペルフルオロ基を表す。
Ｒ _２ は非酸分解性基を表す。Ｒ _２ で表される非酸分解性基は、アルコキシ基、アシル基、−ＯＣ（＝Ｏ）Ｒａ、−ＯＣ（＝Ｏ）ＯＲａ、−Ｃ（＝Ｏ）ＯＲａ、−Ｃ（＝Ｏ）Ｎ（Ｒｂ）Ｒａ、−Ｎ（Ｒｂ）Ｃ（＝Ｏ）Ｒａ、−Ｎ（Ｒｂ）Ｃ（＝Ｏ）ＯＲａ、−Ｎ（Ｒｂ）ＳＯ _２ Ｒａ、−ＳＯ _２ Ｒａ、−ＳＯ _３ Ｒａ、又は、−ＳＯ _２ Ｎ（Ｒｂ）Ｒａである。
Ｒａはアルキル基、シクロアルキル基又はアリール基を表す。
Ｒｂは水素原子、アルキル基、シクロアルキル基又はアリール基を表す。
Ｘは水素原子または有機基を表す。
ｍは１〜４の整数、ｎは１〜４の整数であり、２≦ｎ＋ｍ≦５である。
ｐは１〜４の整数を表す。
ｍまたはｐが２〜４のとき、複数のＸは、同じでも異なっていても良く、ｎが２〜４のとき、複数のＲ _２ は、同じでも異なっていても良い。
一般式（ＩＩ）におけるＲ _１ およびＸは、一般式（Ｉ）におけるＲ _１ およびＸと同じでも異なっていてもよい。
＜２＞ 一般式（Ｉ）で示される繰り返し単位が、一般式（Ｉａ）で示される繰り返し単位であることを特徴とする上記＜１＞に記載のポジ型レジスト組成物。

Ｒ _１ は、水素原子、メチル基、シアノ基、ハロゲン原子又はペルフルオロ基を表す。
Ｒ _２ は非酸分解性基を表す。Ｒ _２ で表される非酸分解性基は、アルコキシ基、アシル基、−ＯＣ（＝Ｏ）Ｒａ、−ＯＣ（＝Ｏ）ＯＲａ、−Ｃ（＝Ｏ）ＯＲａ、−Ｃ（＝Ｏ）Ｎ（Ｒｂ）Ｒａ、−Ｎ（Ｒｂ）Ｃ（＝Ｏ）Ｒａ、−Ｎ（Ｒｂ）Ｃ（＝Ｏ）ＯＲａ、−Ｎ（Ｒｂ）ＳＯ _２ Ｒａ、−ＳＯ _２ Ｒａ、−ＳＯ _３ Ｒａ、又は、−ＳＯ _２ Ｎ（Ｒｂ）Ｒａである。
Ｒａはアルキル基、シクロアルキル基又はアリール基を表す。
Ｒｂは水素原子、アルキル基、シクロアルキル基又はアリール基を表す。
Ｘは水素原子または有機基を表す。
ｎは１〜４の整数である。ｎが２〜４であるとき、複数のＲ _２ は、同じでも異なっていても良い。
＜３＞ 一般式（Ｉ）で示される繰り返し単位が一般式（Ｉｂ）で示される繰り返し単位であることを特徴とする上記＜１＞または＜２＞に記載のポジ型レジスト組成物。

Ｒ _１ は、水素原子、メチル基、シアノ基、ハロゲン原子又はペルフルオロ基を表す。
Ｘは水素原子または有機基を表す。
Ｒ _２ａ 及びＲ _２ｂ は水素原子又は非酸分解性基である。但し、Ｒ _２ａ 及びＲ _２ｂ の少なくとも一つは非酸分解性基である。Ｒ _２ａ 及びＲ _２ｂ で表される非酸分解性基は、アルコキシ基、アシル基、−ＯＣ（＝Ｏ）Ｒａ、−ＯＣ（＝Ｏ）ＯＲａ、−Ｃ（＝Ｏ）ＯＲａ、−Ｃ（＝Ｏ）Ｎ（Ｒｂ）Ｒａ、−Ｎ（Ｒｂ）Ｃ（＝Ｏ）Ｒａ、−Ｎ（Ｒｂ）Ｃ（＝Ｏ）ＯＲａ、−Ｎ（Ｒｂ）ＳＯ _２ Ｒａ、−ＳＯ _２ Ｒａ、−ＳＯ _３ Ｒａ、又は、−ＳＯ _２ Ｎ（Ｒｂ）Ｒａである。
Ｒａはアルキル基、シクロアルキル基又はアリール基を表す。
Ｒｂは水素原子、アルキル基、シクロアルキル基又はアリール基を表す。
＜４＞ 一般式（Ｉ）及び（Ｉａ）におけるＲ _２ で表される非酸分解性基、又は一般式（Ｉｂ）におけるＲ _２ａ 及びＲ _２ｂ の少なくとも一つの非酸分解性基が、アルコキシ基であることを特徴とする上記＜１＞〜＜３＞のいずれかに記載のポジ型レジスト組成物。
＜５＞ 一般式（Ｉ）及び（Ｉａ）におけるＲ _２ で表される非酸分解性基、又は一般式（Ｉｂ）におけるＲ _２ａ 及びＲ _２ｂ の少なくとも一つの非酸分解性基が、メトキシ基であることを特徴とする上記＜４＞に記載のポジ型レジスト組成物。
＜６＞ 一般式（ＩＩ）で示される繰り返し単位が一般式（ＩＩａ）で示される繰り返し単位であることを特徴とする上記＜１＞〜＜５＞のいずれかに記載のポジ型レジスト組成物。

Ｒ _１ は、水素原子、メチル基、シアノ基、ハロゲン原子又はペルフルオロ基を表す。
Ｘは水素原子または有機基を表す。
＜７＞ 樹脂（Ａ）が更に一般式（ＩＩＩ）で示される繰り返し単位を含むことを特徴とする上記＜１＞〜＜６＞のいずれかに記載のポジ型レジスト組成物。

Ｒ _３ 〜Ｒ _５ は、各々独立に、水素原子、フッ素原子、塩素原子、シアノ基またはアルキル基を表す。
Ｘ _１ は、水素原子または有機基を表す。
＜８＞ 上記＜１＞〜＜７＞のいずれかに記載のレジスト組成物によりレジスト膜を形成し、該レジスト膜を露光、現像することを特徴とするパターン形成方法。
尚、本発明は、上記＜１＞〜＜８＞に係る発明であるが、以下、その他についても参考のため記載した。
（１） （Ａ）一般式（Ｉ）で示される繰り返し単位と一般式（ＩＩ）で示される繰り返し単位とを含有する、酸の作用によりアルカリ現像液に対する溶解度が増大する樹脂（Ｂ）活性光線又は放射線の照射により酸を発生する化合物（Ｃ）有機塩基性化合物を含有することを特徴とするポジ型レジスト組成物。 That is, the present invention is achieved by the following configuration.
<1> (A) Resin (B) actinic ray containing a repeating unit represented by general formula (I) and a repeating unit represented by general formula (II) whose solubility in an alkaline developer is increased by the action of an acid Alternatively, a positive resist composition comprising a compound (C), an organic basic compound that generates an acid upon irradiation with radiation.

In general formulas (I) and (II),
R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
R ₂ represents a non-acid-decomposable group. Non-acid-decomposable groups represented by R ₂ are alkoxy groups, acyl groups, —OC (═O) Ra, —OC (═O) ORa, —C (═O) ORa, —C (═O) N. (Rb) Ra, -N (Rb ) C (= O) Ra, -N (Rb) C (= O) ORa, -N (Rb) SO 2 Ra, -SO 2 Ra, -SO 3 Ra, or, a -SO ₂ N (Rb) Ra.
Ra represents an alkyl group, a cycloalkyl group, or an aryl group.
Rb represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.
X represents a hydrogen atom or an organic group.
m is an integer of 1 to 4, n is an integer of 1 to 4, and 2 ≦ n + m ≦ 5.
p represents an integer of 1 to 4.
When m or p is 2 to 4, a plurality of X may be the same or different, and when n is 2 to 4, a plurality of R ₂ may be the same or different.
_{R 1} and X in general formula (II) may be the same or different as _{R 1} and X in the general formula (I).
<2> The positive resist composition as described in <1> above, wherein the repeating unit represented by the general formula (I) is a repeating unit represented by the general formula (Ia).

R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
R ₂ represents a non-acid-decomposable group. Non-acid-decomposable groups represented by R ₂ are alkoxy groups, acyl groups, —OC (═O) Ra, —OC (═O) ORa, —C (═O) ORa, —C (═O) N. (Rb) Ra, -N (Rb ) C (= O) Ra, -N (Rb) C (= O) ORa, -N (Rb) SO 2 Ra, -SO 2 Ra, -SO 3 Ra, or, a -SO ₂ N (Rb) Ra.
Ra represents an alkyl group, a cycloalkyl group, or an aryl group.
Rb represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.
X represents a hydrogen atom or an organic group.
n is an integer of 1-4. When n is 2 to 4, a plurality of R ₂ may be the same or different.
<3> The positive resist composition as described in <1> or <2> above, wherein the repeating unit represented by the general formula (I) is a repeating unit represented by the general formula (Ib).

R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
X represents a hydrogen atom or an organic group.
R _2a and R _2b are a hydrogen atom or a non-acid-decomposable group. However, at least one of R _2a and R _2b is a non-acid-decomposable group. Non-acid-decomposable groups represented by R _2a and R _2b are an alkoxy group, an acyl group, —OC (═O) Ra, —OC (═O) ORa, —C (═O) ORa, —C (= O) N (Rb) Ra, -N (Rb) C (= O) Ra, -N (Rb) C (= O) ORa, -N (Rb) SO 2 Ra, -SO 2 Ra, -SO 3 Ra Or —SO ₂ N (Rb) Ra.
Ra represents an alkyl group, a cycloalkyl group, or an aryl group.
Rb represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.
<4> The non-acid-decomposable group represented by R ₂ in the general formulas (I) and (Ia) , or at least one non-acid-decomposable group of R _2a and R _2b in the general formula (Ib) is an alkoxy group. The positive resist composition as described in any one of <1> to <3> above.
<5> The non-acid-decomposable group represented by R ₂ in the general formulas (I) and (Ia) , or at least one non-acid-decomposable group of R _2a and R _2b in the general formula (Ib) is a methoxy group The positive resist composition as described in <4> above, wherein
<6> The positive resist composition as described in any one of <1> to <5> above, wherein the repeating unit represented by the general formula (II) is a repeating unit represented by the general formula (IIa) .

R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
X represents a hydrogen atom or an organic group.
<7> The positive resist composition as described in any one of <1> to <6>, wherein the resin (A) further contains a repeating unit represented by the general formula (III).

R _{3 to} R ₅ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or an alkyl group.
X ₁ represents a hydrogen atom or an organic group.
<8> A pattern forming method, comprising: forming a resist film from the resist composition according to any one of <1> to <7>, and exposing and developing the resist film.
In addition, although this invention is invention which concerns on said <1>-<8>, below, it described for reference also.
(1) (A) Resin containing a repeating unit represented by general formula (I) and a repeating unit represented by general formula (II) whose solubility in an alkaline developer is increased by the action of an acid (B) actinic rays Alternatively, a positive resist composition comprising a compound (C), an organic basic compound that generates an acid upon irradiation with radiation.

In general formulas (I) and (II),
R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
R ₂ represents a non-acid-decomposable group.
X represents a hydrogen atom or an organic group.
m is an integer of 1 to 4, n is an integer of 1 to 4, and 2 ≦ n + m ≦ 5.
p represents an integer of 1 to 4.
When m or p is 2 to 4, the plurality of X may be the same or different, and when n is 2 to 4, the plurality of R ₂ may be the same or different.
R ₁ and X in the general formula (II) may be the same or different as R ₁ and X in the general formula (I).

(2) The positive resist composition as described in (1) above, wherein the repeating unit represented by the general formula (I) is a repeating unit represented by the general formula (Ia).

R ₁ , R ₂ , X and n are as defined in general formula (I).

(3) The positive resist composition as described in (1) or (2) above, wherein the repeating unit represented by the general formula (I) is a repeating unit represented by the general formula (Ib).

R ₁ and X are as defined in general formula (I).
R _2a and R _2b are a hydrogen atom or a non-acid-decomposable group. However, at least one of R _2a and R _2b is a non-acid-decomposable group.

(4) The positive resist composition as described in any one of (1) to (3) above, wherein the non-acid-decomposable group represented by R ₂ in the general formula (I) contains an oxygen atom. .

(5) The positive resist composition as described in any one of (1) to (4) above, wherein the non-acid-decomposable group represented by R ₂ in formula (I) contains a halogen atom. .

(6) The positive resist composition as described in any one of (1) to (5) above, wherein the repeating unit represented by the general formula (II) is a repeating unit represented by the general formula (IIa) .

R ₁ and X have the same meanings as those in formula (II).

(7) The positive resist composition as described in any one of (1) to (6) above, wherein the resin (A) further contains a repeating unit represented by the general formula (III).

R _{3 to} R ₅ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or an alkyl group.
X ₁ represents a hydrogen atom or an organic group.

Further preferred embodiments include the following configurations.
(8) At least one of X in the general formula (I) and / or the general formula (II) and X _{1 in} the general formula (III) includes an alicyclic structure and / or an aromatic ring structure. The positive resist composition according to any one of (1) to (7) above.
(9) The positive resist composition as described in (1) to (8) above, wherein the non-acid-decomposable group represented by R ₂ in the general formula (I) is an alkoxy group.
(10) The positive resist composition as described in any one of (1) to (9) above, further comprising (D) a surfactant.
(11) The positive type as described in any one of (1) to (10) above, wherein the compound (B) contains (B1) a compound capable of generating an organic sulfonic acid by the action of actinic rays or radiation. Resist composition.

(12) The positive resist composition as described in (11) above, further comprising (B2) a compound that generates carboxylic acid by the action of actinic rays or radiation.
(13) The positive resist composition as described in any one of (1) to (12) above, which further contains a solvent.
(14) The positive resist composition as described in (13) above, which contains propylene glycol monomethyl ether acetate as the solvent.

(15) The positive resist composition as described in (14) above, further containing propylene glycol monomethyl ether as the solvent.
(16) The positive resist composition as described in (1) to (15) above, which is exposed by electron beam, X-ray or EUV irradiation.
(17) A pattern forming method comprising: forming a resist film from the resist composition according to any one of (1) to (16) above; and exposing and developing the resist film.

  The photosensitive composition of the present invention can realize sufficiently good resolution and line edge roughness characteristics, particularly under electron beam or EUV irradiation.

Hereinafter, the compounds used in 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).

[1] Resin (A) whose solubility in an alkaline developer is increased by the action of an acid
The resin (A) whose solubility in an alkaline developer is increased by the action of the acid of the present invention contains a repeating unit represented by the general formula (I) and a repeating unit represented by (II).

In general formulas (I) and (II),
R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
R ₂ represents a non-acid-decomposable group.
X represents a hydrogen atom or an organic group.
m is an integer of 1 to 4, n is an integer of 1 to 4, and 2 ≦ n + m ≦ 5.
p represents an integer of 1 to 4.
When m or p is 2 to 4, the plurality of X may be the same or different, and when n is 2 to 4, the plurality of R ₂ may be the same or different.
R ₁ and X in the general formula (II) may be the same or different as R ₁ and X in the general formula (I).

The perfluoro group as R ₁ is preferably a perfluoromethyl group or a perfluoroethyl group. R ₁ is preferably a hydrogen atom, a methyl group, or a C _m F _{2m + 1} group (m is preferably 1), and particularly preferably a hydrogen atom or a methyl group.

R ₂ represents a non-acid-decomposable group. A non-acid-decomposable group is a group that is not an acid-decomposable group (a group that decomposes by the action of an acid to produce an alkali-soluble group), that is, an acid generated from a photoacid generator or the like upon exposure to a hydroxyl group, A group that does not generate an alkali-soluble group such as a carboxy group.
As the non-acid-decomposable group for R ₂ , for example, a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an acyl group, —OC (═O) Ra, —OC (═O) ORa, —C (= O) ORa, -C ( = O) N (Rb) Ra, -N (Rb) C (= O) Ra, -N (Rb) C (= O) ORa, -N (Rb) SO 2 Ra _{, -SRa, -SO 2 Ra, -SO} 3 Ra, or, may be mentioned -SO ₂ N (Rb) Ra. Hydrogen atoms are not included in non-acid-decomposable groups.
Ra represents an alkyl group, a cycloalkyl group, or an aryl group.
Rb represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.

The alkyl group as R ₂ is, for example, an alkyl group having 1 to 8 carbon atoms, specifically, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, hexyl group, octyl group. Preference is given to groups.
The cycloalkyl group as R ₂ is, for example, a cycloalkyl group having 3 to 15 carbon atoms, and specific examples include a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group.
The alkoxy group as R ₂ is, for example, the above alkoxy group having 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and a cyclohexyloxy group. it can.

The aryl group as R ₂ is, for example, an aryl group having 6 to 15 carbon atoms, and specific examples include a phenyl group, a tolyl group, a naphthyl group, an anthryl group and the like.

The acyl group as R ₂ is, for example, an acyl group having 2 to 8 carbon atoms, and specifically, a formyl group, an acetyl group, a propanoyl group, a butanoyl group, a pivaloyl group, a benzoyl group, and the like are preferably exemplified. it can.

  Each of the above groups may have a substituent, and preferred substituents include a hydroxyl group, a carboxyl group, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), an alkoxy group (methoxy group, ethoxy group, Propoxy group, butoxy group, etc.). As for the cyclic structure, examples of the substituent further include an alkyl group (preferably having 1 to 8 carbon atoms).

The alkyl group, cycloalkyl group or aryl group as Ra and Rb is the same as those exemplified as R ₂ .

  The organic group as X preferably has 1 to 40 carbon atoms and may be an acid-decomposable group or a non-acid-decomposable group.

Examples of the non-acid-decomposable group include the same organic groups as those in the non-acid-decomposable group as R ₂ . (Because it is an organic group, halogen atoms are not included.)
Further, for example, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an alkyloxy group (excluding -O-tertiary alkyl), an acyl group, a cycloalkyloxy group, an alkenyloxy group, an aryloxy group, Examples thereof include an alkylcarbonyloxy group, an alkylamidomethyloxy group, an alkylamide group, an arylamidomethyl group, an arylamido group.
The non-acid-decomposable group is preferably an acyl group, an alkylcarbonyloxy group, an alkyloxy group, a cycloalkyloxy group, an aryloxy group, an alkylamidooxy group or an alkylamido group, more preferably an acyl group or an alkylcarbonyl group. An oxy group, an alkyloxy group, a cycloalkyloxy group, and an aryloxy group;
In the non-acid-decomposable group, the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, or a t-butyl group. As the alkyl group, those having 3 to 10 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclohexyl group and adamantyl group are preferable, and as the alkenyl group, carbon number such as vinyl group, propenyl group, allyl group and butenyl group. Those having 2 to 4 carbon atoms are preferable, those having 2 to 4 carbon atoms such as vinyl group, propenyl group, allyl group and butenyl group are preferable as alkenyl groups, and phenyl group, xylyl group and toluyl group are preferable as aryl groups. And those having 6 to 14 carbon atoms such as cumenyl group, naphthyl group and anthracenyl group are preferable. As the alkoxy group, an alkoxy group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a hydroxyethoxy group, a propoxy group, a hydroxypropoxy group, an n-butoxy group, an isobutoxy group, and a sec-butoxy group is preferable.

As the organic group of the acid-decomposable group of X, for example, —C (R _11a ) (R _12a ) (R _13a ), —C (R _14a ) (R _15a ) (OR _16a ), —CO—OC (R _11a ) ( _R12a ) ( _R13a ).
R _{11a to} R _13a each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. R _14a and R _15a each independently represents a hydrogen atom or an alkyl group. R _16a represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. Two of R _11a , R _12a and R _13a , or two of R _14a , R _15a and R _16a may be bonded to form a ring.
A group having an acid-decomposable group can also be introduced into X in the general formula (I) by modification. Thus, X which introduce | transduced the acid-decomposable group is as follows, for example.
-[C ( _R17a ) ( _R18a )] _p- CO-OC ( _R11a ) ( _R12a ) ( _R13a )
R _17a and R _18a each independently represents a hydrogen atom or an alkyl group. p is an integer of 1 to 4.

  As the repeating unit represented by the general formula (I), a repeating unit represented by the general formula (Ia) is preferable, and a repeating unit represented by the general formula (Ib) is more preferable.

R ₁ , R ₂ , X and n are as defined in general formula (I).
R _2a and R _2b in formula (Ib) are a hydrogen atom or a non-acid-decomposable group, provided that at least one of them is a non-acid-decomposable group. The non-acid-decomposable group as R _2a and R _{2b is} the same as the non-acid-decomposable group as R ₂ in formula (I).

  Specific examples of the repeating unit represented by formula (I) include those contained in the resins used in the examples, but are not limited thereto.

  As the repeating unit represented by the general formula (II), a repeating unit represented by the general formula (IIa) is preferable.

In the formula, R ₁ and X have the same meaning as in general formula (II).

  Although the specific example of the repeating unit represented by general formula (II) below is given, it is not limited to these.

  It is preferable that resin (A) contains the repeating unit shown by general formula (III) with the repeating unit represented by general formula (I) and (II).

R _{3 to} R ₅ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or an alkyl group.
X ₁ represents a hydrogen atom or an organic group.

The alkyl group as R _{3 to} R ₅ is preferably an alkyl group having 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, and a propyl group.

The organic group as X ₁ preferably has 1 to 40 carbon atoms and may be an acid-decomposable group or a non-acid-decomposable group.

Examples of the non-acid-decomposable group include the same organic groups as those in the non-acid-decomposable group as R ₂ . (Because it is an organic group, halogen atoms are not included.)
Further, for example, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an alkyloxy group (excluding -O-tertiary alkyl), an acyl group, a cycloalkyloxy group, an alkenyloxy group, an aryloxy group, Examples thereof include an alkylcarbonyloxy group, an alkylamidomethyloxy group, an alkylamide group, an arylamidomethyl group, an arylamido group.
The non-acid-decomposable group is preferably an acyl group, an alkylcarbonyloxy group, an alkyloxy group, a cycloalkyloxy group, an aryloxy group, an alkylamidooxy group or an alkylamido group, more preferably an acyl group or an alkylcarbonyl group. An oxy group, an alkyloxy group, a cycloalkyloxy group, and an aryloxy group;
In the non-acid-decomposable group, the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, or a t-butyl group. As the alkyl group, those having 3 to 10 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclohexyl group and adamantyl group are preferable, and as the alkenyl group, carbon number such as vinyl group, propenyl group, allyl group and butenyl group. Those having 2 to 4 carbon atoms are preferable, those having 2 to 4 carbon atoms such as vinyl group, propenyl group, allyl group and butenyl group are preferable as alkenyl groups, and phenyl group, xylyl group and toluyl group are preferable as aryl groups. And those having 6 to 14 carbon atoms such as cumenyl group, naphthyl group and anthracenyl group are preferable. As the alkoxy group, an alkoxy group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a hydroxyethoxy group, a propoxy group, a hydroxypropoxy group, an n-butoxy group, an isobutoxy group, and a sec-butoxy group is preferable.

As the organic group of the acid-decomposable group for X ₁ , for example, —C (R _11a ) (R _12a ) (R _13a ), —C (R _14a ) (R _15a ) (OR _16a ), —CO—OC ( R _11a ) (R _12a ) (R _13a ) can be mentioned.
R _{11a to} R _13a each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. R _14a and R _15a each independently represents a hydrogen atom or an alkyl group. R _16a represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group. Two of R _11a , R _12a and R _13a , or two of R _14a , R _15a and R _16a may be bonded to form a ring.
Note that a group having an acid-decomposable group can be introduced into X ₁ by modification. In this way, X ₁ introduced with the acid decomposable group is, for example, as follows.
-[C ( _R17a ) ( _R18a )] _p- CO-OC ( _R11a ) ( _R12a ) ( _R13a ) _R17a and _R18a each independently represents a hydrogen atom or an alkyl group. p is an integer of 1 to 4.

The organic group as X ₁ is preferably an acid-decomposable group having at least one cyclic structure selected from alicyclic, aromatic and bridged alicyclic, and an aromatic group (particularly a phenyl group). Or a structure containing an alicyclic or bridged alicyclic structure represented by the following general formulas (pI) to (pVI).

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

In the general formulas (pI) to (pVI), the alkyl group in R _{12 to} R ₂₅ may be substituted or unsubstituted, and is a linear or branched alkyl group having 1 to 4 carbon atoms. Represents. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group.
Further, the further substituent of the alkyl group includes an alkoxy group having 1 to 4 carbon atoms, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an acyl group, an acyloxy group, a cyano group, a hydroxyl group, A carboxy group, an alkoxycarbonyl group, a nitro group, etc. can be mentioned.

The alicyclic hydrocarbon group in R _{11 to} R _{25 or} the alicyclic hydrocarbon group formed by Z and a carbon atom may be monocyclic or polycyclic. Specific examples include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25. These alicyclic hydrocarbon groups may have a substituent.
Below, the structural example of an alicyclic part is shown among alicyclic hydrocarbon groups.

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

Examples of the substituent that the alicyclic hydrocarbon group may have include an alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group, and an alkoxycarbonyl group. The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, more preferably a substituent selected from the group consisting of a methyl group, an ethyl group, a propyl group, and an isopropyl group. Can be mentioned. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.
The alkyl group, alkoxy group, and alkoxycarbonyl group may further have a substituent. Examples of such a substituent include an alkoxy group having 1 to 4 carbon atoms (methoxy group, ethoxy group, butoxy group). Group), hydroxy group, oxo group, alkylcarbonyl group (preferably 2 to 5 carbon atoms), alkylcarbonyloxy group group (preferably 2 to 5 carbon atoms), alkyloxycarbonyl group group (preferably 2 to 2 carbon atoms). 5), halogen atoms (chlorine atom, bromine atom, fluorine atom, etc.) and the like.

In addition, the resin (A) contains an alkali-soluble group such as a phenolic hydroxyl group, a carboxyl group, a sulfonic acid group, a hexafluoroisopropanol group (—C (CF ₃ ) ₂ ) in order to maintain good developability for an alkali developer. Other suitable polymerizable monomers may be copolymerized so that (OH) can be introduced, and other hydrophobic polymerizable monomers such as alkyl acrylates and alkyl methacrylates may be copolymerized to improve film quality. May be.

  The content of the repeating unit represented by the general formula (I) is preferably 3 to 95 mol%, more preferably 5 to 90 mol%, and particularly preferably 10 to 85 mol% in all repeating units constituting the resin. It is.

  The content of the repeating unit represented by the general formula (II) is preferably 1 to 90 mol%, more preferably 3 to 80 mol%, and particularly preferably 5 to 70 mol% in all repeating units constituting the resin. It is.

  The content of the repeating unit represented by the general formula (III) is preferably 1 to 90 mol%, more preferably 3 to 80 mol%, particularly preferably 5 to 70 mol% in all repeating units constituting the resin. It is.

The content of the repeating unit having an alkali-soluble group such as a hydroxyl group, a carboxy group, or a sulfonic acid group is preferably 1 to 99 mol%, more preferably 3 to 95 mol%, particularly preferably in all repeating units constituting the resin. 5 to 90 mol%.
The content of the repeating unit having an acid-decomposable group is preferably 3 to 95 mol%, more preferably 5 to 90 mol%, and particularly preferably 10 to 85 mol% in all repeating units constituting the resin.

  Resins are synthesized by reacting a precursor of an acid-decomposable group with an alkali-soluble resin as described in European Patent No. 254,533, JP-A-2-258500, No. 3-223860 and No. 4-251259. It can be synthesized by a known synthesis method such as a method or a method of copolymerizing a monomer having an acid-decomposable group with various monomers.

The weight average molecular weight (Mw) of the resin is preferably in the range of 1,000 to 200,000, more preferably in the range of 1,500 to 100,000, particularly preferably 2,000 to 50,000. 000 range. If it is less than 1,000, it is preferably 1000 or more from the viewpoint of preventing film loss in the unexposed area, and preferably 200,000 or less from the viewpoint of the dissolution rate and sensitivity of the resin itself with respect to alkali. Moreover, it is preferable that molecular weight dispersion degree (Mw / Mn) is 1.0-3.0, More preferably, it is 1.0-2.0, Most preferably, it is 1.0-1.6.
Here, the weight average molecular weight is defined by a polystyrene conversion value of gel permeation chromatography.
Moreover, you may use resin (A) in combination of 2 or more types.
The total amount of the resin (A) added is generally 30 to 99% by mass, preferably 40 to 97% by mass, and particularly preferably 50 to 95% by mass with respect to the solid content of the positive resist.

  Although the specific example of resin was mentioned in the Example, it is not limited to them.

[2] Compound (B) that generates acid upon irradiation with actinic rays or radiation
A compound (hereinafter, referred to as “acid generator”) that generates an acid upon irradiation with actinic rays or radiation such as X-rays, electron beams, ion beams, EUV, etc., used in the positive resist composition of the present invention. ) Will be described below.
Acid generators that can be used in the present invention include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, and microresists. Known compounds that generate an acid upon irradiation with actinic rays or radiation and mixtures thereof can be appropriately selected and used.

  For example, diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, organic metal / organic halides, acid generators having o-nitrobenzyl type protecting groups And compounds capable of generating sulfonic acid by photolysis represented by imino sulfonate and the like, and disulfone compounds.

  Further, a group which 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, JP 63- The compounds described in No. 146029 and the like 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.

  Of the compounds that can be decomposed by irradiation with actinic rays or radiation that can be used, those that are particularly effective are described below.

  (1) An iodonium salt represented by the following general formula (PAG1) or a sulfonium salt represented by the general formula (PAG2).

Ar ¹ and Ar ² each independently represents an aryl group. Preferred substituents for the aryl group include an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, a nitro group, a carboxyl group, an alkoxycarbonyl group, a hydroxy group, a mercapto group, and a halogen atom.

R ²⁰¹ , R ²⁰² and R ²⁰³ each independently represents an alkyl group or an aryl group. Preferred are aryl groups having 6 to 14 carbon atoms, alkyl groups having 1 to 8 carbon atoms, and substituted derivatives thereof.
Preferred substituents for the aryl group include an alkoxy group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group and a halogen atom, —SO ₂ Ra, —SO ₃ Ra, — _{OSO 2 Ra, -SO 2 N (} Rb) Ra, -N (Rb) SO 2 Ra (Ra is .Rb a hydrogen atom an alkyl group, a cycloalkyl group or an aryl group, an alkyl group, a cycloalkyl group or an aryl group And represents an alkyl group having 1 to 8 carbon atoms, a carboxyl group, or an alkoxycarbonyl group for an alkyl group.

Z ⁻ represents a non-nucleophilic anion, for example, perfluoroalkanesulfonic acid anions such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ^−, etc. , Pentafluorobenzenesulfonate anion, substituted benzenesulfonate anion, condensed polynuclear aromatic sulfonate anion such as naphthalene-1-sulfonate anion, anthraquinonesulfonate anion, sulfonate group-containing dye, perfluoroalkylcarboxylate anion, alkyl Examples thereof include, but are not limited to, a carboxylate anion and a benzoate anion.

Two of R ²⁰¹ , R ²⁰² and R ²⁰³ and Ar ¹ and Ar ² may be bonded via a single bond or a substituent.

  Specific examples include the following compounds, but are not limited thereto.

  Diphenyl iodonium dodecyl benzene sulfonate, diphenyl iodonium trifluoromethane sulfonate, bis (4-trifluoromethylphenyl) iodonium trifluoromethane sulfonate, bis (4-t-butylphenyl) iodonium camphor sulfonate.

  Triphenylsulfonium dodecylbenzenesulfonate, triphenylsulfonium-2,4,6-trimethylbenzenesulfonate, triphenylsulfonium-2,4,6-triisopropylbenzenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluorooctanesulfonate Triphenylsulfonium perfluorononane sulfonate, triphenylsulfonium camphor sulfonate, triphenylsulfonium perfluorobenzene sulfonate, triphenylsulfonium-3,4-bis (trifluoromethyl) benzene sulfonate.

The onium salts represented by the general formula (PAG1) or (PAG2) are known and can be synthesized by, for example, the methods described in US Pat. Nos. 2,807,648 and 4,247,473, and JP-A-53-101331.
Among the acid generators represented by the general formula (PAG1) or (PAG2), those other than the above specific examples are listed below.

  (2) A disulfone derivative represented by the following general formula (PAG3) or an iminosulfonate derivative represented by the general formula (PAG4).

Ar ³ and Ar ⁴ each independently represents an aryl group.
^R204 represents an alkyl group or an aryl group. A represents an alkylene group, an alkenylene group or an arylene group.
Specific examples include the following compounds, but are not limited thereto.

  Bis (tolyl) disulfone, bis (4-methoxyphenyl) disulfone, bis (4-trifluoromethylphenyl) disulfone, phenyl-4-isopropylphenyldisulfone.

  (3) A diazodisulfone derivative represented by the following general formula (PAG5).

_R205 each independently represents an alkyl group, a cycloalkyl group or an aryl group.
Specific examples include the following compounds, but are not limited thereto.

  Bis (phenylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (tolylsulfonyl) diazomethane, bis (t-butylsulfonyl) diazomethane.

  (4) Moreover, the phenacyl sulfonium derivative represented by the following general formula (PAG6) can also be used as an acid generator.

Here, R _{1 to} R ₅ represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a halogen atom, an alkyloxycarbonyl group or an aryl group, and at least two of R _{1 to} R ₅ are They may combine to form a ring structure.
R ₆ and R ₇ represent a hydrogen atom, an alkyl group, a cycloalkyl group, a cyano group or an aryl group.
Y ₁ and Y ₂ represent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an aromatic group containing a hetero atom, and Y ₁ and Y ₂ may be bonded to form a ring.
Y ₃ represents a single bond or a divalent linking group.
X ⁻ has the same meaning as Z ⁻ in the above (PAG1).
At least one of R ₁ to R ₅ and at least one of Y ₁ or Y ₂ may be bonded to form a ring, or at least one of R ₁ to R ₅ and at least one of R ₆ or R ₇ may be bonded. To form a ring.
It may be bonded via a linking group at any position of R ₁ to R ₇ , or at any position of Y ₁ or Y ₂ and may have two or more (PAG6) structures.

  Specific examples of the compound represented by (PAG6) are shown below, but the present invention is not limited thereto.

  Examples of other acid generators are listed below.

  Among the acid generators, compounds represented by the general formula (PAG1), (PAG2) or (PAG4) are preferable, and compounds represented by the general formula (PAG1) or (PAG2) are more preferable.

Further, a compound capable of generating an organic sulfonic acid by the action of actinic rays or radiation [hereinafter sometimes referred to as (B1) component] is preferable. Examples of the component (B1) include those in which the counter anion Z ⁻ or X ⁻ in the general formula (PAG1), (PAG2), or (PAG6) is a sulfonate anion.

In addition to the component (B1), the component (B) preferably further contains a compound that generates a carboxylic acid by the action of actinic rays or radiation (hereinafter sometimes referred to as the component (B2)). By using the component (B1) and the component (B2) in combination, various performances such as sensitivity and resolving power can be improved. Examples of the component (B2) include those in which the counter anion Z ⁻ or X ⁻ in the general formula (PAG1), (PAG2) or (PAG6) is a carboxylic acid anion.

  The mass ratio of component (B1) / component (B2) is usually 1/1 to 100/1, preferably 1/1 to 10/1.

  The compounds of the component (B1) and the component (B2) can be used alone or in combination of two or more.

  The amount of the compound that generates acid upon decomposition by irradiation with actinic rays or radiation is generally used in the range of 0.001 to 40% by mass, preferably 0 based on the solid content in the composition. 0.01 to 20% by mass, more preferably 0.1 to 10% by mass. The amount of the compound that generates an acid upon decomposition upon irradiation with actinic rays or radiation is preferably 0.001% by mass or more from the viewpoint of sensitivity, and preferably 40% by mass or less from the viewpoint of film shape and profile.

[3] Organic basic compound (C)
The organic basic compound contained in the resist composition of the present invention is preferably a compound having a stronger basicity than phenol. The molecular weight of the organic basic compound is usually 100 to 900, preferably 150 to 800, more preferably 200 to 700. Further, nitrogen-containing basic compounds are particularly preferable.
Preferred nitrogen-containing basic compounds are compounds having structures of the following formulas (A) to (E) as a preferred chemical environment. Formulas (B) to (E) may be part of a ring structure.

Here, R ²⁵⁰ , R ²⁵¹ and R ²⁵² may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, or 6 to 20 carbon atoms. Wherein R ²⁵¹ and R ²⁵² may combine with each other to form a ring.
The alkyl group may be unsubstituted or may have a substituent. Examples of the alkyl group having a substituent include an aminoalkyl group having 1 to 6 carbon atoms and a hydroxyalkyl group having 1 to 6 carbon atoms. preferable.
R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ may be the same or different and each represents an alkyl group having 1 to 6 carbon atoms.
Further preferred compounds are nitrogen-containing basic compounds having two or more nitrogen atoms of different chemical environments in one molecule, and particularly preferably both a substituted or unsubstituted amino group and a ring structure containing a nitrogen atom. Or a compound having an alkylamino group.

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

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

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

  A tetraalkylammonium salt type nitrogen-containing basic compound can also be used. Of these, tetraalkylammonium hydroxide having 1 to 8 carbon atoms (tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra- (n-butyl) ammonium hydroxide, etc.) is particularly preferable. These nitrogen-containing basic compounds are used alone or in combination of two or more.

  The use ratio of the acid generator and the organic basic compound in the composition is preferably acid generator / organic 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 / organic basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

[4] Surfactants In the present invention, surfactants can be used, which are preferable from the viewpoints of film forming properties, pattern adhesion, development defect reduction, and the like.

  Specific examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene Polyoxyethylene alkyl allyl ethers such as nonylphenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Sorbitan fatty acid esters such as rate, polyoxyethylene sorbitan monolaurate, polyoxyethylene Sorbitan mono palmitate - door,

Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, EFTOP EF301, EF303, EF352 (Shin-Akita Kasei) (Made by Co., Ltd.), MegaFuck F171, F173 (Dainippon Ink and Chemicals), Florad FC430, FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC101, SC102 , SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), Troysol S-366 (manufactured by Troy Chemical Co., Ltd.), etc., or a silicon surfactant, organosiloxane polymer KP341 Shin-Etsu Chemical Co., Ltd.) and acrylic or methacrylic acid-based (co) polymer Polyflow No. 75, no. 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.). The compounding amount of these surfactants is usually 2 parts by mass or less, preferably 1 part by mass or less per 100 parts by mass of the solid content in the composition of the present invention.
These surfactants may be added alone or in several combinations.

The surfactant is any one of fluorine and / or silicon surfactants (fluorine surfactants and silicon surfactants, surfactants containing both fluorine atoms and silicon atoms), or It is preferable to contain 2 or more types.
As these surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540 No. 7, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, JP-A 2002-277862, US Pat. No. 5,405,720. , No. 5,360,692, No. 5,529,881, No. 5,296,330, No. 5,543,098, No. 5,576,143, No. 5,294,511, No. 5,824,451. The following commercially available surfactants can also be used as they are.
Examples of commercially available surfactants that can be used include EFTOP EF301 and EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430 and 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, and R08. (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. 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). It may be a unit having different chain lengths in the same chain length, such as a block linked body) or a poly (block linked body of oxyethylene and oxypropylene) group. 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 ₆ F ₁₃ group and (poly (oxy) (Ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

  The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the positive resist composition (excluding the solvent).

[5] Other components The positive resist composition of the present invention may further contain a dye, a photobase generator and the like, if necessary.

1. Dye A dye can be used in the present invention.
Suitable dyes include oily dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Co., Ltd.), crystal violet (CI42555), methyl violet (CI42535), rhodamine B (CI45170B), malachite green (CI42000), methylene blue (CI522015) and the like.

2. Photobase generator As photobase generators that can be added to the composition of the present invention, JP-A-4-151156, JP-A-4-162040, JP-A-5-197148, JP-A-5-5995, JP-A-6-194835, Examples thereof include compounds described in JP-A-8-146608, JP-A-10-83079 and European Patent No. 622682, specifically, 2-nitrobenzylcarbamate, 2,5-dinitrobenzylcyclohexylcarbamate, N-cyclohexyl-4- Methylphenylsulfonamide, 1,1-dimethyl-2-phenylethyl-N-isopropylcarbamate and the like can be suitably used. These photobase generators are added for the purpose of improving the resist shape and the like.

3. Solvents The resist composition of the present invention is dissolved in a solvent that dissolves each of the above components and coated on a support. The solid content concentration of all resist components is usually preferably 2 to 30% by mass, more preferably 3 to 25% by mass.
Solvents used here include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate , Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethyl Formamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran and the like are preferable. Or mixed to use. As the solvent, those containing propylene glycol monomethyl ether acetate are preferred, and those containing propylene glycol monomethyl ether are more preferred.

4). Zwitterionic compound (Y)
It is preferable that the photosensitive resin composition of the present invention further contains a zwitterionic compound. Here, the zwitterionic compound refers to a compound containing both a cation moiety and an anion moiety in one molecule. Specific examples include amphoteric ions of amino acids such as alanine, phenylalanine, asparagine, glycine, and valine, but are not limited thereto.
The addition amount is preferably 3 to 70 mol%, more preferably 5 to 50 mol%, and still more preferably 7 to 40 mol%, relative to the component (B1). By adding the component (Y), sensitivity and contrast are further improved.

  In the resist composition of the present invention, it is desirable to suppress the generation of particles (particulate aggregates) due to sensitivity fluctuations as much as possible. In general, when the metal content is large, the number of particles increases because the resin aggregates in the solution with the metal as a core. Therefore, in the composition of the present invention, it is preferable that the amount of metal components such as Na, K, Ca, Fe, and Mg contained in the resin of component (A) is small. Specifically, the metal species content contained in the resin is preferably 300 ppb or less, more preferably 200 ppb or less, and still more preferably 100 ppb or less.

  When the content of metal impurities in the resist is high, the number of particles is likely to increase because the resin aggregates in the solvent with the metal impurities serving as nuclei with time. In addition, the aggregation of the resin is presumed to cause a substantial change in components constituting the resist composition and contribute to sensitivity fluctuations.

Here, examples of metal impurities contained in the resist composition include Na, K, Ca, Fe, Mg, Mn, Pd, Ni, Zn, Pt, Ag, and Cu.
As a method for reducing the content of metal impurities contained in the resist composition, that is, the number of particles, for example, a method in which a resin is dissolved in a solvent to form a solution and filtered through an ion exchange filter, liquid separation washing, acidic ion A treatment with an exchange resin or a chelate resin is known.
As a method of reducing the content of metal impurities in the chemically amplified resist composition of the present invention, there are a step of filtering a solution containing the resin of the present invention through an ion exchange filter, and then a photoacid generator and, if necessary, the solution. A method comprising preparing a mixed solution by adding an organic basic compound, a surfactant and the like, and then filtering the mixed solution through an insoluble colloid removing filter is preferable.

As the ion exchange filter that can be used, a cation exchange type filter in which an ion exchange group is fixed to a polyethylene porous membrane or a polypropylene porous membrane is preferable. For example, Ion Clean (manufactured by Nihon Pall), Ion Clean AQ (Japan) Paul)). The filtration rate by the ion exchange filter is preferably 500 to 10,000 cc / min / m ² . As the insoluble colloid removal filter, a synthetic resin filter is preferable. For example, Microlith Optimizer DEV-16 / 40 (Microlith Polyethylene Filter), Microguard Minichem (Microlith Polyethylene Filter), Enflon ( (Nippon Pole Polytetrafluoroethylene Filter), Ultipore N66 (Nippon Pole Nylon 66 Filter), Zeta Plus (Cuno Cellulose Filter), Electropore II (Cuno Nylon 66 Filter), and the like. . Moreover, when performing a filtration process after adding ionic compounds, such as a photo-acid generator, it is preferable that an insoluble colloid removal filter does not have an ion exchange ability. The pore sizes of the ion exchange filter and the insoluble colloid removal filter are both preferably 0.01 to 0.5 μm, and more preferably 0.01 to 0.1 μm.

  The resist composition of the present invention is applied onto a substrate to form a thin film. The thickness of the resist film is preferably 0.05 to 4.0 μm.

  In the present invention, a commercially available inorganic or organic antireflection film can be used if necessary. Furthermore, an antireflection film can be applied to the resist lower layer and used.

  As the antireflection film used as the lower layer of the resist, either an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, amorphous silicon, or an organic film type made of a light absorber and a polymer material may be used. it can. The former requires equipment such as a vacuum deposition apparatus, a CVD apparatus, and a sputtering apparatus for film formation. Examples of the organic antireflection film include a condensate of a diphenylamine derivative and a formaldehyde-modified melamine resin described in JP-B-7-69611, an alkali-soluble resin, a light absorber, and maleic anhydride copolymer described in US Pat. No. 5,294,680. A reaction product of a coalescence and a diamine type light absorbent, a resin binder described in JP-A-6-186863 and a methylolmelamine thermal crosslinking agent, a carboxylic acid group, an epoxy group and a light-absorbing group described in JP-A-6-118656. An acrylic resin type antireflection film in the same molecule, a composition comprising methylol melamine and a benzophenone light absorber described in JP-A-8-87115, and a low molecular light absorber added to a polyvinyl alcohol resin described in JP-A-8-179509 And the like.

  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 are also used. it can.

  In the manufacture of precision integrated circuit elements, the pattern forming process on the resist film is carried out on the substrate (eg, silicon / silicon dioxide coated substrate, glass substrate, ITO substrate, quartz / chromium oxide coated substrate, etc.). A resist pattern is applied and dried to form a resist film, followed by irradiation with X-rays, electron beams, ion beams or EUV, preferably by heating, developing, rinsing and drying to form a good resist pattern can do.

Examples of the alkaline developer of the resist composition of the present invention include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine and the like. Secondary amines such as amines, diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; tetramethylammonium hydroxide; tetraethylammonium An aqueous solution (usually 0.1 to 20% by mass) of an alkali such as a quaternary ammonium salt such as hydroxide or choline, a cyclic amine such as pyrrole or piperidine, or the like can be used. Furthermore, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant may be added to the alkaline aqueous solution.
Among these developers, quaternary ammonium salts are preferable, and tetramethylammonium hydroxide and choline are more preferable.
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.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, the content of this invention is not limited by this. In addition, Example 5, 8-10, 13, 23, and 24 shall be read as Reference Example 5, 8-10, 13, 23, and 24.

  (Synthesis Example 1) Synthesis of Polymer 1a

In a reaction vessel, 96.1 g (0.5 mol) of 3-methoxy-4-acetoxystyrene (Honshu Chemical) and 81.1 g (0.5 mol) of 4-acetoxystyrene (Honshu Chemical) were dissolved in 400 ml of tetrahydrofuran. Nitrogen gas was allowed to flow through the system while stirring. Thereto, 23.0 g (0.1 mol) of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction solution was heated to 65 ° C. After stirring with heating for 10 hours, the reaction solution was allowed to cool to room temperature and dropped into 5 L of hexane to precipitate the polymer. The filtered solid was dissolved in 600 ml of acetone, dropped again into 5 L of hexane, and the filtered solid was dried under reduced pressure to obtain 150.6 g of (3-methoxy-4-acetoxystyrene)-(4-acetoxystyrene) copolymer. It was.
To the reaction vessel, 130 g of the polymer obtained above, 500 ml of methanol, 500 ml of 1-methoxy-2-propanol, 2.0 ml of concentrated hydrochloric acid and 30 ml of distilled water were added, heated to 80 ° C. and stirred for 5 hours. The reaction solution was allowed to cool to room temperature and dropped into 3 L of distilled water. The filtered solid was dissolved in 120 ml of acetone, dropped again into 3 L of distilled water, and the filtered solid was dried under reduced pressure to obtain 79.3 g of polymer 1a. The weight average molecular weight by GPC was 8000, the molecular weight dispersity was 1.55, and the composition ratio determined from 1H-NMR was 51/49 in order from the left of the figure.

  (Synthesis Example 2) Synthesis of Polymer 1b

In a reaction vessel, distilled-purified 3-methoxy-4- (1-ethoxyethoxy) styrene 111.2 g (0.5 mol), 4- (1-ethoxyethoxy) styrene (Tosoh) 96.1 g (0.5 mol) ) Was dissolved in 500 ml of dehydrated tetrahydrofuran, and nitrogen gas was allowed to flow through the system while stirring, followed by cooling to -78 ° C. Thereto was added 0.02 mol of n-butyllithium to initiate polymerization. A part of the reaction solution was sampled every 30 minutes to check the degree of polymerization. When the desired degree of polymerization was reached, methanol was added to the reaction solution to stop the polymerization. After waiting until the reaction solution reached room temperature, the reaction solution was dropped into 5 L of methanol to precipitate a polymer. The filtered solid was dissolved in 300 ml of acetone, dropped again into 5 L of methanol, and the filtered solid was dried under reduced pressure to give [3-methoxy-4- (1-ethoxyethoxy) styrene]-[4- (1-ethoxyethoxy) 153.4 g of a styrene copolymer was obtained.
150 g of the polymer obtained above, 700 ml of tetrahydrofuran, 300 ml of methanol, 20 ml of distilled water and 1.0 g of p-toluenesulfonic acid were added to the reaction vessel, and the mixture was stirred at room temperature for 5 hours. Thereafter, the reaction solution was dropped into 4 L of distilled water. The filtered solid was dissolved in 300 ml of acetone, dropped again into 4 L of distilled water, and the filtered solid was dried under reduced pressure to obtain 78.3 g of polymer 1b. The weight average molecular weight by GPC was 8000, the molecular weight dispersity was 1.09, and the composition ratio determined from 1H-NMR was 50/50 in order from the left of the figure.
The raw material 3-methoxy-4- (1-ethoxyethoxy) styrene is obtained by deprotecting the acetyl group of 3-methoxy-4-acetoxystyrene (manufactured by Honshu Kagaku) by a conventional method, and then using phenolic OH with ethyl vinyl ether. And can be synthesized in a conventional manner.

(Synthesis Example 3) Synthesis of Polymer A-1

In a reaction vessel, 30 g of the polymer 1a obtained in Synthesis Example 1 or the polymer 1b obtained in Synthesis Example 2 was dissolved in 100 g of PGMEA, and this solution was decompressed to 60 mm and 20 mmHg, and about 20 g of solvent was added to the system. Distilled off with the remaining water. The mixture was cooled to 20 ° C., 12.76 g of 2-phenoxyethyl vinyl ether and 1.0 g of p-toluenesulfonic acid were added, and the mixture was stirred at room temperature for 1 hour. Thereafter, 1.16 g of triethylamine was added for neutralization, and 40 g of ethyl acetate and 40 g of water were added for washing operation three times. Thereafter, the amount of the solvent was adjusted to obtain a 30% by mass polymer solution. Let this polymer be A-1a and A-1b, respectively. Polymer A-1a had a weight average molecular weight of 8800 by GPC and a molecular weight dispersion of 1.57. From ¹ H and ¹³ C-NMR analysis, the composition ratio was 44/7/21/28 in order from the left of the figure. It was. The weight average molecular weight 8500 by GPC of the polymer A-1b, the molecular weight dispersity was 1.10, from ¹ H and ¹³ C-NMR analysis, the composition ratio is in the order from the left in FIG 45/5/21/29 Met.
Polymers A-2 to A-12 and polymers A-27 to A-29 were obtained in the same manner as in Synthesis Examples 1, 2, and 3 except that the monomers and vinyl ethers used were changed.

  (Synthesis Example 4) Synthesis of Polymer A-13

In a reaction vessel, 10.38 g (0.054 mol) of 3-methoxy-4-acetoxystyrene (Honshu Chemical), 7.46 g (0.046 mol) of 4-acetoxystyrene (Honshu Chemical), t-butyl acrylate 92 g (0.054 mol) was dissolved in 60 ml of tetrahydrofuran, and nitrogen gas was allowed to flow through the system while stirring. 2.76 g (0.012 mol) of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto, and the reaction solution was heated to 65 ° C. After stirring with heating for 10 hours, the reaction solution was allowed to cool to room temperature and dropped into 500 ml of hexane to precipitate the polymer. The filtered solid was dissolved in 40 ml of acetone, dropped again into 500 ml of hexane, and the filtered solid was dried under reduced pressure to obtain 21.79 g of a polymer.
20 g of the polymer obtained above, 200 ml of tetrahydrofuran, 30 ml of methanol, 10 ml of distilled water and 12.7 g of tetramethylammonium hydroxide were added to the reaction vessel and stirred at room temperature for 5 hours. Thereafter, the reaction solution was dropped into 500 ml of distilled water. The filtered solid was dissolved in 40 ml of acetone, dropped again into 500 ml of distilled water, and the filtered solid was dried under reduced pressure to obtain 12.0 g of polymer A-13. The weight average molecular weight by GPC was 9600, and the molecular weight dispersity was 1.38. Further, from ¹ H and ¹³ C-NMR analysis, the composition ratio was 34/30/36 in order from the left in the figure.
Polymers A-14 to A-26 were obtained in the same manner as in Synthesis Examples 4 and 5 except that the monomers used were changed.
The structures of the polymers A-1 to A-29 are shown below.

  Resins H-1 and H-2 used as comparative resins are the following resins.

(Preparation of resist composition)
Resin of the present invention shown in Table 2: 0.948 g (in terms of solid content)
Acid generator: 0.05g
Organic basic compound: 0.003 g
Surfactant: 0.002 g was dissolved in 16.79 g of the solvent shown in Table 2 below to prepare a solution having a solid content concentration of 5.0% by mass. This solution was filtered through a 0.1 μm Teflon (registered trademark) filter to obtain a positive resist solution.

〔particle〕
The number of particles in the liquid of the adjusted positive resist composition was measured using a particle counter manufactured by Rion. The number of particles of 0.2 μm or more in 1 ml of the resist solution was counted.

[Pattern preparation and evaluation (EB)]
Using a spin coater, the positive resist solution prepared as described above is uniformly coated on a silicon wafer that has been subjected to hexamethyldisilazane treatment, and is heated and dried at 120 ° C. for 90 seconds to form a positive film having a thickness of 0.3 μm. A mold resist film was formed. The resist film was irradiated with an electron beam using an electron beam drawing apparatus (HL750 manufactured by Hitachi, Ltd., acceleration voltage 50 KeV). After irradiation, the substrate was baked at 100 ° C. for 90 seconds, immersed in an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution for 60 seconds, rinsed with water for 30 seconds, and dried. The obtained pattern was evaluated by the following method.

[Resolution]
The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.). Sensitivity is the minimum irradiation energy when resolving a 150 nm line (line: space = 1: 1), and the limiting resolution (minimum line width at which the line and space can be obtained as a separate resolution) at the dose that shows the above sensitivity. Resolution was taken.

[Line edge roughness]
The distance from the reference line where there should be an edge, using a scanning electron microscope (S-9220, manufactured by Hitachi, Ltd.) for any 30 points in the length direction of 50 μm of the 150 nm line pattern at the irradiation dose showing the sensitivity described above. Was measured, the standard deviation was obtained, and 3σ was calculated.
The results are shown in Table 2.

  Abbreviations in Table 2 are as follows.

[Surfactant]
D-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.)
D-2: Megafuck R08 (manufactured by Dainippon Ink & Chemicals, Inc.)
D-3: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
D-4: Polyoxyethylene lauryl ether [solvent]
S-1: Propylene glycol monomethyl ether acetate S-2: Propylene glycol monomethyl ether [basic compound]
N-1: Trioctylamine N-2: 1,5-diazabicyclo [4.3.0] -5-nonene N-3: 2,4,6-triphenylimidazole

  From the results in Table 2, it can be seen that the resist composition of the present invention has a high resolution and excellent line edge roughness as compared with the composition of the comparative example with respect to pattern formation by electron beam irradiation.

[Pattern preparation and evaluation (EUV)]
Using the resist compositions of Examples 2, 6, 7, 25, and 28 and Comparative Examples 1, 2, and 3, resist films were obtained in the same manner as in Example 1. However, the resist film thickness was 0.15 μm. The obtained resist film was subjected to surface exposure using EUV light (wavelength 13 nm) while changing the exposure amount by 0.5 mJ in the range of 0 to 10.0 mJ, and further baked at 100 ° C. for 90 seconds. Then, using a 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution, the dissolution rate at each exposure amount was measured to obtain a sensitivity curve. In this sensitivity curve, the exposure amount when the dissolution rate of the resist is saturated was taken as sensitivity, and the dissolution contrast (γ value) was calculated from the gradient of the linear portion of the sensitivity curve. The larger the γ value, the better the dissolution contrast. These results are shown in Table 3 as Examples 31 to 35 and Comparative Examples 4, 5, and 6, respectively.

  From the results of Table 3, it can be seen that the resist composition of the present invention is superior in sensitivity and high contrast and superior in comparison with the composition of the comparative example in the characteristic evaluation by irradiation with EUV light.

Claims (8)

(A) Resin containing a repeating unit represented by general formula (I) and a repeating unit represented by general formula (II) whose solubility in an alkaline developer is increased by the action of an acid (B) actinic rays or radiation A positive resist composition comprising a compound (C) that generates an acid upon irradiation and an organic basic compound.

In general formulas (I) and (II),
R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
R ₂ represents a non-acid-decomposable group. Non-acid-decomposable groups represented by R ₂ are alkoxy groups, acyl groups, —OC (═O) Ra, —OC (═O) ORa, —C (═O) ORa, —C (═O) N. (Rb) Ra, -N (Rb ) C (= O) Ra, -N (Rb) C (= O) ORa, -N (Rb) SO 2 Ra, -SO 2 Ra, -SO 3 Ra, or, a -SO ₂ N (Rb) Ra.
Ra represents an alkyl group, a cycloalkyl group, or an aryl group.
Rb represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.
X represents a hydrogen atom or an organic group.
m is an integer of 1 to 4, n is an integer of 1 to 4, and 2 ≦ n + m ≦ 5.
p represents an integer of 1 to 4.
When m or p is 2 to 4, a plurality of X may be the same or different, and when n is 2 to 4, a plurality of R ₂ may be the same or different.
_{R 1} and X in the general formula (II) may be the same or different as _{R 1} and X in the general formula (I). The positive resist composition according to claim 1, wherein the repeating unit represented by the general formula (I) is a repeating unit represented by the general formula (Ia).

R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
R ₂ represents a non-acid-decomposable group. Non-acid-decomposable groups represented by R ₂ are alkoxy groups, acyl groups, —OC (═O) Ra, —OC (═O) ORa, —C (═O) ORa, —C (═O) N. (Rb) Ra, -N (Rb ) C (= O) Ra, -N (Rb) C (= O) ORa, -N (Rb) SO 2 Ra, -SO 2 Ra, -SO 3 Ra, or, a -SO ₂ N (Rb) Ra.
Ra represents an alkyl group, a cycloalkyl group, or an aryl group.
Rb represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.
X represents a hydrogen atom or an organic group.
n is an integer of 1-4. When n is 2 to 4, a plurality of R ₂ may be the same or different. 3. The positive resist composition according to claim 1, wherein the repeating unit represented by the general formula (I) is a repeating unit represented by the general formula (Ib).

R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
X represents a hydrogen atom or an organic group.
R _2a and R _2b are a hydrogen atom or a non-acid-decomposable group. However, at least one of R _2a and R _2b is a non-acid-decomposable group. Non-acid-decomposable groups represented by R _2a and R _2b are an alkoxy group, an acyl group, —OC (═O) Ra, —OC (═O) ORa, —C (═O) ORa, —C (= O) N (Rb) Ra, -N (Rb) C (= O) Ra, -N (Rb) C (= O) ORa, -N (Rb) SO 2 Ra, -SO 2 Ra, -SO 3 Ra Or —SO ₂ N (Rb) Ra.
Ra represents an alkyl group, a cycloalkyl group, or an aryl group.
Rb represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.   R in general formulas (I) and (Ia) ₂ Or a non-acid-decomposable group represented by general formula (Ib) _2a And R _2b The positive resist composition according to claim 1, wherein the at least one non-acid-decomposable group is an alkoxy group.   R in general formulas (I) and (Ia) ₂ Or a non-acid-decomposable group represented by general formula (Ib) _2a And R _2b The positive resist composition according to claim 4, wherein at least one non-acid-decomposable group is a methoxy group. 6. The positive resist composition according to claim 1, wherein the repeating unit represented by the general formula (II) is a repeating unit represented by the general formula (IIa).

R ₁ represents a hydrogen atom, a methyl group, a cyano group, a halogen atom or a perfluoro group.
X represents a hydrogen atom or an organic group. Resin (A) contains the repeating unit further shown by general formula (III), The positive resist composition in any one of Claims 1-6 characterized by the above-mentioned.

R _{3 to} R ₅ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or an alkyl group.
X ₁ represents a hydrogen atom or an organic group.   A pattern forming method comprising: forming a resist film from the resist composition according to claim 1; and exposing and developing the resist film.