JP2007057604A - Positive resist composition and pattern forming method using positive resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition which can be suitably used when ArF excimer laser light is used as an exposure light source, excels in line edge roughness, and causes neither pattern collapse nor problem of development defects, and a pattern forming method using the same, and to further provide a positive resist composition excellent in pattern profile and exposure latitude and a pattern forming method using the same. <P>SOLUTION: The positive resist composition contains (A) a compound capable of generating an acid upon irradiation with an actinic ray or radiation, (B) a resin which is decomposed by the action of an acid to increase its solubility in an alkali developer, and (C) a low-molecular compound having a specific lactone structure. The pattern forming method using the positive resist composition is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positive resist composition used for manufacturing semiconductor substrates such as ICs, circuit boards such as liquid crystals and thermal heads, and other photofabrication processes, and pattern formation using the positive resist composition. It is about the method. More specifically, the present invention relates to a positive resist composition suitable for microfabrication of a semiconductor device using light energy rays having a short wavelength such as far ultraviolet rays, X-rays, and electron beams, and a pattern forming method using the positive resist composition. In particular, the present invention relates to a positive resist composition suitably used for microfabrication of a semiconductor element using an ArF excimer laser and a pattern forming method using the positive resist composition.

In recent years, semiconductor integrated circuits have been highly integrated, LSIs and VLSIs have been put into practical use, and the minimum pattern width of integrated circuits has reached the sub-half micron range, and further miniaturization has progressed.
For this reason, the demand for a photolithography technique for forming a fine pattern is becoming stricter. As one of means for miniaturizing a pattern, it is known to shorten the wavelength of exposure light used for forming a resist pattern.
For example, in the manufacture of a DRAM having a degree of integration up to 64 Mbits, i-line (365 nm) of a high-pressure mercury lamp has been used as a light source until now. In the mass production process of 256Mbit DRAM, KrF excimer laser (248nm) is put into practical use as exposure light reduction instead of i line. Furthermore, the use of shorter wavelength light sources, ArF excimer laser (193 nm), F2 excimer laser (157 nm), X-rays, and electron beams has been studied for the purpose of manufacturing DRAM having a degree of integration of 1 Gbit or more.
In particular, ArF excimer laser is positioned as the next-generation exposure technology, and it is desired to develop a resist with high sensitivity and high resolution for ArF excimer laser exposure.
A chemical amplification type resist is used for lithography pattern formation in this wavelength region. In general, chemically amplified resists combine a compound that generates an acid upon irradiation with actinic rays or radiation and a binder resin. The binder resin is a resin having in its molecule a group (also referred to as an acid-decomposable group) that decomposes by the action of an acid and increases the solubility of the resin in an alkaline developer. In addition to the above compounds, the chemical amplification resist may contain a low molecular compound having a specific structure.
In lithography using chemically amplified resists, in general, sensitivity, resolution, shape, coatability, heat resistance, dry etching resistance, adhesion, substrate dependency, and environmental stability (for example, resist dimensions due to fluctuations in holding time) (Stability) and depth of focus (for example, pattern formation with respect to defocus during radiation irradiation) are required, and many devices have been disclosed for improving performance with additives. ing.
For example, Patent Document 1 (Japanese Patent Laid-Open No. 2001-109156) and Patent Document 2 (US Pat. No. 6,627,391B) describe compositions containing an acid-decomposable resin and a low-molecular additive having a lactone group. Has been.
The problem of line edge roughness is particularly problematic for the recent trend of miniaturization and higher throughput. Line edge roughness means that the resist line 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. It means that it looks uneven. This unevenness hinders the resolution of the pattern, or is transferred by an etching process using a resist as a mask to deteriorate the electrical characteristics, thereby reducing the yield. Furthermore, since the aspect ratio has become severe with respect to the film thickness due to the recent miniaturization, the pattern is very easy to collapse, and this tendency is particularly remarkable in the resist for ArF. Here, the pattern collapse includes all those that fall due to insufficient adhesion and those that fall due to insufficient film strength. In addition, the problem of development defects is also serious, and as a photoresist composition for an ArF light source, a resin having an alicyclic hydrocarbon moiety introduced for the purpose of imparting dry etching resistance has been proposed. Since the system becomes extremely hydrophobic as a detrimental effect of the introduction of hydrocarbon sites, development with an aqueous solution of tetramethylammonium hydroxide (hereinafter referred to as TMAH), which has been widely used as a resist developer, becomes difficult or during development. There are phenomena such as the resist peeling off from the substrate. In order to solve the problems of pattern collapse and development defects, an approach has been made to compensate for the influence of the hydrophobic part of the resin, specifically the alicyclic hydrocarbon part, by introducing hydrophilic groups. In many cases, the dry etching resistance deteriorates, and the resist film becomes prominent, resulting in many problems such as increased line edge roughness.

Japanese Patent Laid-Open No. 2001-109156 US Pat. No. 6,627,391B

  Accordingly, an object of the present invention is to provide a positive resist composition that is excellent in line edge roughness and has no pattern collapse when a deep ultraviolet ray, particularly ArF excimer laser light is used as an exposure light source, and does not cause a development defect problem. Another object of the present invention is to provide a pattern forming method using the positive resist composition. Furthermore, it is providing the positive resist composition excellent in pattern profile and exposure latitude, and the pattern formation method using this positive resist composition.

  As a result of intensive studies on the constituent materials of the positive resist composition, the present inventors have found that (A) a compound that generates an acid upon irradiation with actinic rays or radiation, (B) a solubility in an alkali developer that decomposes by the action of the acid. A positive resist that has excellent line edge roughness, pattern profile and exposure latitude, and does not cause pattern collapse and does not cause development defects by combining a resin having an increased amount and (C) a low molecular weight compound having a specific lactone structure. Knowing that a composition can be obtained, the present invention has been achieved. That is, the present invention is a positive resist composition having the following constitution and a pattern forming method using the positive resist composition, whereby the object of the present invention is achieved.

(1) (A) a compound that generates an acid upon irradiation with actinic rays or radiation,
A positive resist comprising (B) a resin which is decomposed by the action of an acid and increases the solubility in an alkaline developer, and (C) a low molecular compound having a lactone structure represented by the following general formula (C1) Composition.

In general formula (C1),
L ₁ represents an organic group necessary for forming a ring structure with two carbon atoms in the lactone ring in the general formula (C1).
R ₁ and R ₂ each independently represents a hydrogen atom, an organic group or a hydroxyl group. R ₁ and R ₂ may combine with each other to form a ring.

  (2) A pattern forming method comprising a step of forming a resist film with the positive resist composition according to (1), and exposing and developing the resist film.

  According to the present invention, there are provided a positive resist composition with reduced development defects, line edge roughness, pattern collapse, increased exposure latitude and excellent pattern profile, and a pattern forming method using the positive resist composition. can do. It is not well understood why the positive resist composition of the present invention is specifically superior to the above-mentioned development defects, line edge roughness and pattern collapse reduction, exposure latitude increase, and pattern profile improvement. However, it is considered that (C) is expressed by a low molecular compound having a specific lactone structure, specifically, a low molecular compound having a lactone structure represented by the general formula (C1).

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).

[1] (A) Compound capable of generating acid upon irradiation with actinic ray or radiation As (A) compound used in the present invention for generating acid upon irradiation with actinic ray or radiation (hereinafter also referred to as “acid generator”) Can be selected from compounds generally used as acid generators.
That is, it generates an acid upon irradiation with actinic rays or radiation used for photoinitiators of photocationic polymerization, photoinitiators of photoradical polymerization, photodecolorants of dyes, photochromic agents, or microresists. Known compounds 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.

Preferred compounds among the acid generators include the following general formulas (ZI), (ZII), (ZIII
) Can be mentioned.

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

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

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

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

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

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

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

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

  The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  Examples of the sulfonylimide anion include saccharin anion.

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

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

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

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

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

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

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

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

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

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

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

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

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
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.
Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (ZI).

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

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

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

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

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

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

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

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

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

Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group. Aryl group R ₂₀₄ to R ₂₀₇ represents an oxygen atom, a nitrogen atom, may be an aryl group having a heterocyclic structure having a sulfur atom and the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like.

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

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

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

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

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

In general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₆ , R ₂₀₇ and R ₂₀₈ each independently represents an alkyl group, a cycloalkyl group or an aryl group, and these are the same as the alkyl group, cycloalkyl group or aryl group as R _{204 to} R ₂₀₇ .
A represents an alkylene group, an alkenylene group or an arylene group.

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

  The acid generator in the present invention is particularly preferably an acid having an anion structure containing an alkyl group having 4 or less carbon atoms substituted with a fluorine atom or an aromatic group substituted with a fluorine atom, and a triarylsulfonium cation structure. It is a generator. Such acid generators are preferably those represented by the following general formulas (B1) to (B3).

In general formulas (B1) to (B3),
R ₁ represents an alkyl group, an alicyclic hydrocarbon group, a hydroxyl group, a carboxyl group, an alkoxy group or a halogen atom.
y represents 0 or an integer of 1 to 5 independently of each other. When y is an integer of 2 or more, two or more R _{1 s} may be the same or different.
Q _{1 to} Q ₄ are each independently an alkyl group having 1 to 8 carbon atoms substituted with a fluorine atom, a cycloalkyl group substituted with a fluorine atom, an aryl group substituted with a fluorine atom, or a fluorinated alkyl group. Represents a substituted aryl group.

As the alkyl group for R ₁ , a linear or branched alkyl group having 1 to 15 carbon atoms is preferable, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, and a t-butyl group. Can be mentioned.
Examples of the alicyclic hydrocarbon group for R ₁ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, and the like.
The alkyl group substituted with a fluorine atom of Q _{1 to} Q ₄ may be further substituted with an alkoxy group, a fluoroalkoxy group or the like. For example, —CF ₃ , —C ₂ F ₅ , —n—C ₃ F _{7, -n-C 4 F 9} , -CF (CF 3) 2, -CH (CF 3) 2, - (CF 2) 2 OCF 2 CF 3, - (CF 2) 2 O (CH 2) 3 CH _{3, - (CF 2) 2} O (CH 2) 13 CH 3, - (CF 2) 2 O (CF 2) 2 (CH 2) 3 CH 3 and the like.
Examples of the aryl group substituted with a fluorine atom of Q _{1 to} Q ₄ include 2,3,4,5,6-pentafluorophenyl group, 2,3,4-trifluorophenyl group, and 2,4-difluoro. A phenyl group, 4-fluorophenyl group, 4-undecanyloxy-2,3,5,6-tetrafluorophenyl group and the like can be mentioned.
Examples of the aryl group substituted with a fluorinated alkyl group of Q _{1 to} Q ₄ include a 3-trifluoromethylphenyl group, a 3,5-bis (trifluoromethyl) phenyl group, a 4-trifluoromethylphenyl group, And 4-n-nonafluorobutylphenyl group.

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

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

[2] (B) Resin that is decomposed by the action of an acid to increase the solubility in an alkaline developer The positive resist composition of the present invention is a resin that decomposes by the action of an acid to increase the solubility in an alkaline developer (hereinafter, “ Acid-decomposable resin (B) ").
The acid-decomposable resin (B) has a group (hereinafter also referred to as “acid-decomposable group”) that is decomposed by the action of an acid to increase the solubility in an alkali developer.
Examples of the acid-decomposable group include a group in which a hydrogen atom of an alkali-soluble group such as a carboxyl group, a hydroxyl group, a sulfonic acid group, and a thiol group is protected with a group capable of leaving by the action of an acid.
Examples of the group capable of leaving by the action of an acid include —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R 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.

  When the positive resist composition of the present invention is irradiated with ArF excimer laser light, the acid-decomposable resin (B) has a monocyclic or polycyclic alicyclic hydrocarbon structure and is decomposed by the action of an acid. A resin that increases the solubility in an alkali developer is preferable.

  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) A resin having one type of repeating unit is preferred.

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.
Z represents an atomic group necessary for forming a cycloalkyl group together with a carbon atom.
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 the 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, such as a methyl group, an ethyl group, n- A propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, etc. can be mentioned.

The cycloalkyl group represented by R _{12 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.

  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.

  The alkyl group and cycloalkyl group may further have a substituent. As further substituents for 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 (2 to 2 carbon atoms). 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 structure represented by the general formulas (pI) to (pV) in the resin can form an acid-decomposable group by using it for protecting an alkali-soluble group. 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 carboxyl group, a hydroxyl group, a sulfonic acid group, or a thiol group is substituted with a structure represented by the general formulas (pI) to (PV), preferably a carboxyl group, a hydroxyl group The hydrogen atom of the sulfonic acid group is substituted with the structure represented by the 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.

In the general formula (pA),
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. To express. A single bond is preferable.
Rp1 represents any group of the above formulas (pI) to (pV).

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

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

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

Examples of the alkyl group for R ₁₁ ′ and R ₁₂ ′ include linear or branched alkyl groups 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 the resin, and in particular, a bridged alicyclic ring An atomic group for forming a bridged alicyclic structure forming a repeating unit of the formula hydrocarbon is preferred.

Examples of the skeleton of the alicyclic hydrocarbon formed include those similar to the cycloalkyl groups represented by 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 type of repeating unit among the repeating unit having, the repeating unit represented by the general 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 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 (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure is used. This improves line edge roughness and development defects.

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 3 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 an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, a single bond, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group obtained by combining these. Represents. Preferably a single bond, -Ab ₁ -CO ₂ - is a linking group represented by. Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexyl group, an adamantyl group, or a norbornyl 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 preferably has a repeating unit having an alicyclic hydrocarbon structure substituted with a polar group. This improves the substrate adhesion and developer compatibility. The polar group is preferably a hydroxyl group or a cyano group.
Examples of the alicyclic hydrocarbon structure substituted with a polar group include groups represented by the following general formula (VIIa) or (VIIb).

In general formula (VIIa),
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 remaining is a hydrogen atom, more preferably two of R _{2c to} R _4c are a hydroxyl group and the remaining is a hydrogen atom.

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

As the repeating unit having a group represented by the general formula (VIIa) or (VIIb), at least one of R ₁₃ ′ to R ₁₆ ′ in the general formula (II-AB1) or (II-AB2) is the above. Those having a group represented by the general formula (VIIa) or (VIIb) (for example, R _{5 in} —COOR ₅ represents a group represented by the general formula (VIIa) or (VIIb)), or the following general formula (AIIa ) Or (AIIb).

In general formulas (AIIa) and (AIIb),
R _1c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

  Specific examples of the repeating unit represented by the general formula (AIIa) or (AIIb) are shown below, but the present invention is not limited thereto.

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

In 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. Most preferred are acrylic acid and 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 following general formula (F1). This improves line edge roughness performance.

In general formula (Z),
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 the general formula (F1) is preferably a repeating unit represented by the following general formula (F2).

In general formula (F2),
Rxb represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. Preferable substituents that the Rxb alkyl group 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 in Fb is preferably a cyclopentyl group, a cyclohexyl group, or a norbornyl group.

  Hereinafter, although the specific example of the repeating unit which has a structure of general formula (F1) is shown, this invention is not limited to this.

  The alicyclic hydrocarbon-based acid-decomposable resin of the present invention may further have 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, cyclohexyl (meth) acrylate, and the like.

  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. It can have various repeating structural units 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.

Thereby, performance required for the alicyclic hydrocarbon-based acid-decomposable resin, in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.

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. can be mentioned.

  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) Containing repeating unit represented by general formula (II-AB) (main chain type) However, in (2), the following are further exemplified.
(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 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 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% of 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 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 repeating units. In this case, all of the repeating units may be methacrylate, all of the repeating units may be acrylate, or a mixture of methacrylate / acrylate, but the acrylate repeating unit is preferably 50 mol% or less of the entire repeating unit. More 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 containing the lactone structure, It is a terpolymer having 5 to 30 mol% of repeating units having an alicyclic hydrocarbon structure substituted with a polar group, or a quaternary copolymer containing 0 to 20 mol% of other repeating units.

Particularly preferred acid-decomposable resins (B) include 20 to 50 mol% of repeating units having an acid-decomposable group represented by the following (ARA-1) to (ARA-5), (ARL-1) to (ARL -6) repeating unit 5 having a lactone group represented by 20 to 50 mol% and an alicyclic hydrocarbon structure substituted with a polar group represented by (ARH-1) to (ARH-3) 5 A terpolymer having ˜30 mol%, or a carboxyl group, or a repeating unit having a structure represented by the general formula (F1), or an alicyclic hydrocarbon structure, and having no acid decomposability It is a quaternary copolymer having 5 to 20 mol% of units.
(In the formula, Rxy ₁ represents a hydrogen atom or a methyl group, and Rxa ₁ and Rxb ₁ each independently represents a methyl group or an ethyl group.)

The acid-decomposable resin (B) 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 the polymerization is performed by heating, 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 the solvent used in the positive resist composition of the present invention. Thereby, the generation of particles during storage 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 acid-decomposable resin (B) according to the present invention is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, particularly preferably as a polystyrene conversion value by the GPC method. Is 5,000 to 15,000. 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 molecular weight distribution is usually 1 to 5, preferably 1 to 3, and more preferably 1 to 2. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.

In the positive resist composition of the present invention, the blending amount of all the acid-decomposable resins (B) according to the present invention in the entire composition is preferably 50 to 99.99% by mass, more preferably in the total solid content. It is 60-99.0 mass%.
In the present invention, the acid-decomposable resin (B) may be used alone or in combination.

[3] (C) Low molecular compound having lactone structure represented by general formula (C1) The positive resist composition of the present invention comprises a low molecular compound having a lactone structure represented by the following general formula (C1) ( Hereinafter, it is also referred to as “component (C)”.

In general formula (C1),
L ₁ represents an organic group necessary for forming a ring structure with two carbon atoms in the lactone ring in the general formula (C1).
R ₁ and R ₂ each independently represents a hydrogen atom, an organic group or a hydroxyl group. R ₁ and R ₂ may combine with each other to form a ring.

In general formula (C1), the ring structure formed by L ₁ together with two carbon atoms in the lactone ring in general formula (C1) may be monocyclic or polycyclic, Is a 4- to 8-membered ring, more preferably a 5- to 6-membered ring. Particularly preferred examples include a pentane ring and a norbornene ring. The organic group of L ₁ may have at least one divalent group having a hetero atom. Examples of the divalent group having a hetero atom include an ether group, a thioether group, an ester group, an amide group, and a sulfonamide group. Examples of the ring structure having a heteroatom include a structure in which at least one methylene group constituting a ring skeleton in a corresponding carbocyclic ring such as a pentane ring or a norbornene ring is replaced with a divalent group having a heteroatom. Can be mentioned. The number of heteroatoms contained in the ring structure to be formed is preferably 1 to 2. The ring structure constituted by L ₁ may be substituted with an alkyl group, a hydroxyl group or the like.

Examples of the organic group represented by R ₁ and R _{2 in} the general formula (C1) include an alkyl group, a cycloalkyl group, an acyl group, an aryl group, an alkoxy group, an acyloxy group, and an alkoxycarbonyl group. .
In the general formula (C1), the alkyl group represented by R ₁ and R ₂ is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, isopentyl group, neopentyl group, t-pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, A tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an eicosyl group, and the like can be given.
The cycloalkyl group of R ₁ and R ₂ may be monocyclic or polycyclic. The monocyclic type is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable. For example, an adamantyl group, norbornyl group, isobornyl group, camphanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, tetracyclododecyl group. Group, androstanyl group and the like.
The aryl group of R ₁ and R ₂ is preferably an aryl group having 6 to 14 carbon atoms. For example, a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a biphenyl residue (by the loss of one hydrogen atom from biphenyl) Group formed), p-terphenyl residue (group formed by losing one hydrogen atom from p-terphenyl), and the like.
Examples of the organic group of Ra in the alkoxy group (Ra-O-) and alkoxycarbonyl group (Ra-O-CO-) of R ₁ and R ₂ include the same alkyl groups and cycloalkyl groups as described above. it can.
As the organic group for Rb in the acyl group (Rb—CO—) and the acyloxy group (Rb—CO—O) for R ₁ and R ₂ , the same alkyl group, cycloalkyl group, aryl group, and carbon number as described above are used. Examples thereof include 2 to 15 alkenyl groups.
When R ₁ and R ₂ are combined to form a ring together, the group R ₁ and R ₂ is formed by bonding with, for example, includes an alkylene group having 2 to 8 carbon atoms.
R ₁ and R ₂ may further have a substituent such as a hydroxyl group or a halogen atom.
In the component (C), one compound and at least one other compound may be bonded to each other via a group R ₁ or R ₂ .

  In the component (C), the lactone group is decomposed by the action of an alkali to produce an alkali-compatible carboxylic acid. Examples of the alkali herein include pH 8 to 14, preferably 10 to 14, specifically, for example, tetramethylammonium hydroxide aqueous solution (concentration 2.38% by mass) used also in a developer. .

  As a preferable form of general formula (C1), the following general formula (C2) can be mentioned.

In general formula (C2),
R _{1 to} R ₆ each independently represents a hydrogen atom, an organic group or a hydroxyl group, and these may be bonded to each other to form a ring.
R ₁ and R ₂ have the same meanings as R ₁ and R _{2 in} formula (C1), and R _{3 to} R ₆ are the same as R ₁ and R ₂ .
X represents an oxygen atom or a sulfur atom.

  As another preferred embodiment of the general formula (C1), the following general formula (C3) can be exemplified.

In general formula (C3),
R ₂ represents a hydrogen atom, an organic group or a hydroxyl group. R ₂ has the same meaning as R _{2 in} formula (C1).
L ₁ represents an organic group necessary for forming a ring structure. L ₁ has the same meaning as L _{1 in} formula (C1).
L ₂ represents an n-valent linking group. Examples of the n-valent linking group of L ₂ include a residue in which n hydrogen atoms are lost from an aliphatic compound having 1 to 15 carbon atoms and an aromatic compound having 6 to 15 carbon atoms.
n represents an integer of 2 to 8.

  As a more preferable form of general formula (C1), the following general formula (C4) can be mentioned.

In general formula (C4),
R _{1 to} R ₆ each independently represents a hydrogen atom, an organic group or a hydroxyl group. These may combine with each other to form a ring. R < ₁ > -R < ₆ > is synonymous with R < ₁ > -R < ₆ > in general formula (C2).
R ₇ and R ₈ each independently represents a hydrogen atom, an organic group or a hydroxyl group. R ₇ and R ₈ are the same as R ₁ to R _6.
L ₃ represents a divalent linking group. Examples of the divalent linking group of L ₃ include a methylene group, an ethylene group, and an ether group.

  The compound group in (C1) to (C4) includes all of optical isomers depending on the structure.

  Component (C) is, for example, J. Am. Chem. Soc. (1982), p4659, the method described in Tetrahedron Asymmetry (1993), p1341, the method described in Tetrahedron Letters, (1995), p9333, and the like.

  Specific examples of the component (C) are given below. However, the present invention is not limited to these compounds.

  (C) The molecular weight of a component becomes like this. Preferably it is 3000 or less, More preferably, it is 150-2000, More preferably, it is 200-1000. By setting the molecular weight of the component (C) to 150 or more, deterioration of the pattern profile due to sublimation from the resist film can be prevented.

In the present invention, the amount of component (C) used is generally 0.01 to 9% by mass, preferably 0.1 to 7% by mass, more preferably based on the solid content in the positive resist composition. Is 0.5-5 mass%. In order to obtain a sufficient effect, the content is preferably 0.01% by mass or more, and is preferably 9% by mass or less from the viewpoint of suppressing a decrease in sensitivity, a decrease in exposure latitude, and a significant film loss.
These compounds may be added alone or in several combinations.

[4] (D) Organic solvent The positive resist composition of the present invention is used by dissolving the above components in a predetermined organic solvent. Examples of the organic solvent that can be used include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl. Ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N -Dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, etc. These solvents can be used alone or in combination.
Among these, preferable solvents include cyclohexanone, 2-heptanone, γ-butyrolactone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl. Examples include ether acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, N-methylpyrrolidone, and tetrahydrofuran.
It is also preferable to mix two or more solvents, and particularly preferred is a mixed solvent of a solvent containing no hydroxyl group and a solvent containing a hydroxyl group. Further, from the viewpoint of improving the film thickness uniformity and development defect performance, it is preferable to mix a high boiling point solvent having a boiling point of 200 ° C. or higher such as ethylene carbonate, propylene carbonate, and γ-butyrolactone.

[5] (E) Basic compound The positive resist composition of the present invention preferably further contains a basic compound.
As the basic compound, an organic amine, a basic ammonium salt, a basic sulfonium salt, a basic iodonium salt, or the like is used as long as it does not deteriorate sublimation or resist performance. The basic compound is a component having an action of controlling a diffusion phenomenon in a resist film of an acid generated from an acid generator by exposure and suppressing an undesirable chemical reaction in a non-exposed region. By compounding such a basic compound, the storage stability of the positive resist composition that can control the diffusion phenomenon of the acid generated from the acid generator upon exposure in the resist film is improved, and the resolution as a resist is improved. As a result, it is possible to suppress a change in the line width of the resist pattern due to fluctuations in the holding time (PED) from exposure to development processing, and a composition having excellent process stability can be obtained.

  As the basic compound, organic amines can be used. For example, primary, secondary, tertiary aliphatic amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group And nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amide derivatives, imide derivatives, nitrogen-containing compounds having a cyano group, and the like.

As aliphatic amines, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, pentylamine, tert-amylamine, cyclopentylamine, hexylamine, cyclohexylamine, Heptylamine, octylamine, nonylamine, decylamine, dodecylamine, cetylamine, methylenediamine, ethylenediamine,
Tetraethylenepentamine, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-sec-butylamine, dipentylamine, dicyclopentylamine, dihexylamine, dicyclohexylamine, diheptyl Amine, dioctylamine, dinonylamine, didecylamine, didodecylamine, dicetylamine, N, N-dimethylmethylenediamine, N, N-dimethylethylenediamine, N, N-dimethyltetraethylenepentamine, trimethylamine, triethylamine, tri-n-propylamine , Triisopropylamine, tri-n-butylamine, triisobutylamine, tri-sec-butylamine, tripentylamine, tricyclopentyl Min, trihexylamine, tricyclohexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, tridodecylamine, tricetylamine, N, N, N ′, N′-tetramethylmethylenediamine, N , N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethyltetraethylenepentamine, dimethylethylamine, methylethylpropylamine, benzylamine, phenethylamine, benzyldimethylamine, etc. The

  Aromatic amines and heterocyclic amines include aniline derivatives such as aniline, N-methylaniline, N-ethylaniline, N-propylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, ethylaniline, propylaniline, trimethylaniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline, 3,5-dinitroaniline, N, N-dimethyltoluidine, etc.), diphenyl (p-tolyl) amine, methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine, diaminonaphthalene, pyrrole derivatives (eg pyrrole, 2H-pyrrole, 1-methylpyrrole, 2,4 -Dimethylpyro , 2,5-dimethylpyrrole, N-methylpyrrole, etc.), oxazole derivatives (eg oxazole, isoxazole etc.), thiazole derivatives (eg thiazole, isothiazole etc.), imidazole derivatives (eg imidazole, 4-methylimidazole, 4 -Methyl-2-phenylimidazole, etc.), pyrazole derivatives, furazane derivatives, pyrroline derivatives (eg pyrroline, 2-methyl-1-pyrroline etc.), pyrrolidine derivatives (eg pyrrolidine, N-methylpyrrolidine, pyrrolidinone, N-methylpyrrolidone etc.) ), Imidazoline derivatives, imidazolidine derivatives, pyridine derivatives (eg pyridine, methylpyridine, ethylpyridine, propylpyridine, butylpyridine, 4- (1-butylpentyl) pyridine, dimethylpyridine) Trimethylpyridine, triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine, 4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine, 1-methyl-2-pyridone, 4- Pyrrolidinopyridine, 1-methyl-4-phenylpyridine, 2- (1-ethylpropyl) pyridine, aminopyridine, dimethylaminopyridine, etc.), pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives, pyrazoline derivatives, pyrazolidine derivatives, piperidine derivatives, Piperazine derivatives, morpholine derivatives, indole derivatives, isoindole derivatives, 1H-indazole derivatives, indoline derivatives, quinoline derivatives (eg quinoline, 3-quinolinecarbonitrile) Etc.), isoquinoline derivatives, cinnoline derivatives, quinazoline derivatives, quinoxaline derivatives, phthalazine derivatives, purine derivatives, pteridine derivatives, carbazole derivatives, phenanthridine derivatives, acridine derivatives, phenazine derivatives, 1,10-phenanthroline derivatives, adenine derivatives, adenosine derivatives Guanine derivatives, guanosine derivatives, uracil derivatives, uridine derivatives and the like.

Examples of the nitrogen-containing compound having a carboxy group include aminobenzoic acid, indolecarboxylic acid, amino acid derivatives (eg, nicotinic acid, alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, glycylleucine, leucine, methionine, phenylalanine. , Threonine, lysine, 3-aminopyrazine-2-carboxylic acid, methoxyalanine) and the like.

  Examples of the nitrogen-containing compound having a sulfonyl group include 3-pyridinesulfonic acid and pyridinium p-toluenesulfonate.

  Examples of the nitrogen-containing compound having a hydroxyl group include 2-hydroxypyridine, aminocresol, 2,4-quinolinediol, 3-indolemethanol hydrate, monoethanolamine, diethanolamine, triethanolamine, N-ethyldiethanolamine, N, N- Diethylethanolamine, triisopropanolamine, 2,2′-iminodiethanol, 2-aminoethanol, 3-amino-1-propanol, 4-amino-1-butanol, 4- (2-hydroxyethyl) morpholine, 2- (2-hydroxyethyl) pyridine, 1- (2-hydroxyethyl) piperazine, 1- [2- (2-hydroxyethoxy) ethyl] piperazine, piperidine ethanol, 1- (2-hydroxyethyl) pyrrolidine, 1- (2 -Hydroxyethyl ) -2-pyrrolidinone, 3-piperidino-1,2-propanediol, 3-pyrrolidino-1,2-propanediol, 8-hydroxyeurolidine, 3-quinuclidinol, 3-tropanol, 1-methyl-2 -Pyrrolidine ethanol, 1-aziridine ethanol, N- (2-hydroxyethyl) phthalimide, N- (2-hydroxyethyl) isonicotinamide and the like are exemplified.

  Examples of amide derivatives include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide and the like.

  Examples of imide derivatives include phthalimide, succinimide, maleimide and the like.

  Specific examples of the nitrogen-containing compound having a cyano group include 3- (diethylamino) propiononitrile, N, N-bis (2-hydroxyethyl) -3-aminopropiononitrile, N, N-bis (2- Acetoxyethyl) -3-aminopropiononitrile, N, N-bis (2-formyloxyethyl) -3-aminopropiononitrile, N, N-bis (2-methoxyethyl) -3-aminopropiononitrile, N, N-bis [2- (methoxymethoxy) ethyl] -3-aminopropiononitrile, methyl N- (2-cyanoethyl) -N- (2-methoxyethyl) -3-aminopropionate, N- (2 -Cyanoethyl) -N- (2-hydroxyethyl) -3-aminopropionic acid methyl, N- (2-acetoxyethyl) -N- (2-cyanoethyl) Methyl 3-aminopropionate, N- (2-cyanoethyl) -N-ethyl-3-aminopropiononitrile, N- (2-cyanoethyl) -N- (2-hydroxyethyl) -3-aminopropiononitrile, N- (2-acetoxyethyl) -N- (2-cyanoethyl) -3-aminopropiononitrile, N- (2-cyanoethyl) -N- (2-formyloxyethyl) -3-aminopropiononitrile, N -(2-cyanoethyl) -N- (2-methoxyethyl) -3-aminopropiononitrile, N- (2-cyanoethyl) -N- [2- (methoxymethoxy) ethyl] -3-aminopropiononitrile, N- (2-cyanoethyl) -N- (3-hydroxy-1-propyl) -3-aminopropiononitrile, N- (3-acetoxy-1-pro ) -N- (2-cyanoethyl) -3-aminopropiononitrile, N- (2-cyanoethyl) -N- (3-formyloxy-1-propyl) -3-aminopropiononitrile, N- (2 -Cyanoethyl) -N-tetrahydrofurfuryl-3-aminopropiononitrile, N, N-bis (2-cyanoethyl) -3-aminopropiononitrile, diethylaminoacetonitrile, N, N-bis (2-hydroxyethyl) amino Acetonitrile, N, N-bis (2-acetoxyethyl) aminoacetonitrile, N, N-bis (2-formyloxyethyl) aminoacetonitrile, N, N-bis (2-methoxyethyl) aminoacetonitrile, N, N-bis [2- (Methoxymethoxy) ethyl] aminoacetonitrile, N-cyanomethyl-N- (2 -Methoxyethyl) -3-aminopropionic acid methyl, N-cyanomethyl-N- (2-hydroxyethyl) -3-aminopropionic acid methyl, N- (2-acetoxyethyl) -N-cyanomethyl-3-aminopropionic acid Methyl, N-cyanomethyl-N- (2-hydroxyethyl) aminoacetonitrile, N- (2-acetoxyethyl) -N- (cyanomethyl) aminoacetonitrile, N-cyanomethyl-N- (2-formyloxyethyl) aminoacetonitrile, N-cyanomethyl-N- (2-methoxyethyl) aminoacetonitrile, N-cyanomethyl-N- [2- (methoxymethoxy) ethyl] aminoacetonitrile, N- (cyanomethyl) -N- (3-hydroxy-1-propyl) Aminoacetonitrile, N- (3-acetoxy-1 Propyl) -N- (cyanomethyl) aminoacetonitrile, N-cyanomethyl-N- (3-formyloxy-1-propyl) aminoacetonitrile, N, N-bis (cyanomethyl) aminoacetonitrile, 1-pyrrolidinepropiononitrile, 1- Piperidine propiononitrile, 4-morpholine propiononitrile, 1-pyrrolidine acetonitrile, 1-piperidine acetonitrile, 4-morpholine acetonitrile, cyanomethyl 3-diethylaminopropionate, N, N-bis (2-hydroxyethyl) -3-aminopropion Cyanomethyl acid, cyanomethyl N, N-bis (2-acetoxyethyl) -3-aminopropionate, cyanomethyl N, N-bis (2-formyloxyethyl) -3-aminopropionate, N, N-bis (2- Toxiethyl) -3-aminopropionate cyanomethyl, N, N-bis [2- (methoxymethoxy) ethyl] -3-aminopropionate cyanomethyl, 3-diethylaminopropionic acid (2-cyanoethyl), N, N-bis (2 -Hydroxyethyl) -3-aminopropionic acid (2-cyanoethyl), N, N-bis (2-acetoxyethyl) -3-aminopropionic acid (2-cyanoethyl), N, N-bis (2-formyloxyethyl) ) -3-Aminopropionic acid (2-cyanoethyl), N, N-bis (2-methoxyethyl) -3-aminopropionic acid (2-cyanoethyl), N, N-bis [2- (methoxymethoxy) ethyl] -3-aminopropionic acid (2-cyanoethyl), cyanomethyl 1-pyrrolidinepropionate, 1-piperidine Examples include cyanomethyl lopionate, cyanomethyl 4-morpholine propionate, 1-pyrrolidine propionic acid (2-cyanoethyl), 1-piperidine propionic acid (2-cyanoethyl), 4-morpholine propionic acid (2-cyanoethyl).

  As the basic compound, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,4-diazabicyclo [2. 2.2] Octane, 4-dimethylaminopyridine, 1-naphthylamine, piperidines, hexamethylenetetramine, imidazoles, hydroxypyridines, pyridines, anilines, hydroxyalkylanilines, 4,4′-diaminodiphenyl ether, pyridinium p-toluenesulfonate, 2,4,6-trimethylpyridinium p-toluenesulfonate, tetramethylammonium p-toluenesulfonate, and tetrabutylammonium lactate, triethylamine, tributylamine, tripentylamine, tri-n-octylamine , Tri-i-octylamine, tris (ethylhexyl) amine, tridecylamine, tridodecylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri -N-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, cyclohexyldimethylamine, methyldicyclohexylamine, ethylenediamine, N, N, N ', N'-tetramethylethylenediamine, tetra Methylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4-aminophenyl) Propane, 2- (3-a Minophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene, bis (2-dimethyl) Tri (cyclo) alkylamines such as aminoethyl) ether, bis (2-diethylaminoethyl) ether, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, tricyclohexylamine; aniline, N— Methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitro Aromatic amines such as aniline, diphenylamine, triphenylamine, naphthylamine, 2,6-diisopropylaniline, polyethyleneimine, polyallylamine, 2-dimethylaminoethylacrylamide polymer, Nt-butoxycarbonyldi-n-octyl Amine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt -Butoxycarbonyl-N-methyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, N -T-butoxycal Nyl-4,4′-diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N′N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N′-di -T-butoxycarbonyl-1,7-diaminoheptane, N, N'-di-t-butoxycarbonyl-1,8-diaminooctane, N, N'-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminododecane, N, N′-di-t-butoxycarbonyl- 4,4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt- Toxicarbonyl-2-phenylbenzimidazole, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, urea Methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea, imidazole, 4-methylimidazole, Imidazoles such as 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridy Pyridines such as 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine; piperazine, 1- (2-hydroxy In addition to piperazines such as ethyl) piperazine, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1 , 4-diazabicyclo [2.2.2] octane.

  Among these, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,4-diazabicyclo [2.2.2] Octane, 4-dimethylaminopyridine, 1-naphthylamine, piperidine, 4-hydroxypiperidine, 2,2,6,6-tetramethyl-4-hydroxypiperidine, hexamethylenetetramine, imidazoles, hydroxypyridines, pyridines, 4 , 4'-diaminodiphenyl ether, triethylamine, tributylamine, tripentylamine, tri-n-octylamine, tris (ethylhexyl) amine, tridodecylamine, N, N-di-hydroxyethylaniline, N-hydroxyethyl-N- Organic amines such as ethylaniline are particularly preferred.

The positive resist composition of the present invention may further contain an ammonium salt compound. Specific examples of the ammonium salt include the following compounds, but are not limited thereto.
Specifically, ammonium hydroxide, ammonium triflate, ammonium pentaflate, ammonium heptaflate, ammonium nonaflate, ammonium undecaflate, ammonium tridecaflate, ammonium pentadecaflate, ammonium methylcarboxylate, ammonium ethylcarboxylate, Ammonium propyl carboxylate, ammonium butyl carboxylate, ammonium heptyl carboxylate, ammonium hexyl carboxylate, ammonium octyl carboxylate, ammonium nonyl carboxylate, ammonium decyl carboxylate, ammonium undecyl carboxylate, ammonium dodecadecyl carboxylate, ammonium salt Decyl carboxylate, ammonium tetradecyl carboxylate, ammonium pentadecyl carboxylate, ammonium hexadecyl carboxylate, ammonium heptadecyl carboxylate, ammonium octadecyl carboxylate and the like.

  That is, as the ammonium hydroxide, specifically, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, Tetraheptylammonium hydroxide, methyltrioctylammonium hydroxide, tetraoctylammonium hydroxide, didecyldimethylammonium hydroxide, tetrakisdecylammonium hydroxide, dodecyltrimethylammonium hydroxide, dodecylethyldimethylammonium hydroxide, didodecyldimethylammonium hydroxy And tridodecylmethylammonium Droxide, myristylmethylammonium hydroxide, dimethylditetradecylammonium hydroxide, hexadecyltrimethylammonium hydroxide, octadecyltrimethylammonium hydroxide, dimethyldioctadecylammonium hydroxide, tetraoctadecylammonium hydroxide, diallyldimethylammonium hydroxide, (2 -Chloroethyl) -trimethylammonium hydroxide, (2-bromoethyl) trimethylammonium hydroxide, (3-bromopropyl) -trimethylammonium hydroxide, (3-bromopropyl) triethylammonium hydroxide, glycidyltrimethylammonium hydroxide, choline hydroxy (R)-(+)-(3-chloro-2- (Droxypropyl) trimethylammonium hydroxide, (S)-(−)-(3-chloro-2-hydroxypropyl) -trimethylammonium hydroxide, (3-chloro-2-hydroxypropyl) -trimethylammonium hydroxide, ( 2-aminoethyl) -trimethylammonium hydroxide, hexamethonium hydroxide, decamethonium hydroxide, 1-azoniaproperan hydroxide, petronium hydroxide, 2-chloro-1,3-dimethyl-2-imidazoli Examples thereof include nium hydroxide and 3-ethyl-2-methyl-2-thiazolinium hydroxide.

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%. By setting it as 0.001-10 mass%, the effect of addition of the said component is acquired and the tendency for the fall of a sensitivity and the developability of a non-exposed part to deteriorate can be prevented.
Only one type of basic compound may be used, or two or more types may be used.

[6] (F) Fluorine-based and / or silicon-based surfactant The positive resist composition of the present invention further comprises a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, It is preferable to contain any one of surfactants containing both fluorine atoms and silicon atoms, or two or more thereof. When the positive resist composition of the present invention contains the above-mentioned surfactant, a resist pattern with good sensitivity and resolution and less adhesion and development defects can be obtained when using an exposure light source of 250 nm or less, particularly 220 nm or less. It becomes possible to give.

  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, JP-A-63-34540 7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, U.S. Patents 5405720, 5360692, 5529881, 5296330, 5436098, 5576143 , Nos. 5294511 and 5842451, and the following commercially available surfactants can be used as they are.

  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 OMNIVA), 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.

  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).

[7] (G) Dissolution-inhibiting compound having a molecular weight of 3000 or less that decomposes by the action of an acid to increase the solubility in an alkaline developer. The positive resist composition of the present invention may further contain an acid, if necessary. Contains a dissolution inhibiting compound having a molecular weight of 3000 or less (hereinafter also referred to as “dissolution inhibiting compound”), which decomposes by action to increase the solubility in an alkaline developer.
The dissolution inhibiting compound has an acid-decomposable group such as a cholic acid derivative containing an acid-decomposable group described in Proceeding of SPIE, 2724,355 (1996) so as not to lower the permeability of 220 nm or less. Alicyclic or aliphatic compounds are preferred. Examples of the acid-decomposable group and alicyclic structure are the same as those described above for the acid-decomposable resin (B).
The molecular weight of the dissolution inhibiting compound in the present invention is 3000 or less, preferably 300 to 3000, and more preferably 500 to 2500.
The addition amount of the dissolution inhibiting compound is preferably 1 to 30% by mass and more preferably 2 to 20% by mass with respect to the solid content of the positive resist composition.

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

The positive resist composition of the present invention further contains a dye, a plasticizer, a surfactant other than the component (F), a photosensitizer, a compound that promotes solubility in a developer, and the like as necessary. Can be made.
The dissolution-promoting compound for the developer that can be used in the present invention is a low-molecular compound having a molecular weight of 1,000 or less and having two or more phenolic OH groups.
A preferable addition amount of the dissolution promoting compound is preferably 2 to 50% by mass, more preferably 5 to 30% by mass with respect to the resin of the component (B). By making the addition amount 2 to 50% by mass, it is possible to prevent development residue from deteriorating and deformation of the pattern during development.

  Such a phenol compound having a molecular weight of 1000 or less can be easily synthesized by those skilled in the art with reference to the methods described in, for example, JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, and the like. can do.

  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 for manufacturing a precision integrated circuit element by an appropriate coating method such as a spinner or a coater, and dried to form a resist film. Form.
The resist 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.
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 resist film so that the immersion medium and the resist film do not come into direct contact with each other during the immersion exposure. Thereby, elution of the composition from the resist film to the immersion medium is suppressed, and development defects are reduced.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., but preferably far ultraviolet light having a wavelength of 250 nm or less, more preferably 220 nm or less. 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) An electron beam is preferred.

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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this.

Synthesis Example 1 (Synthesis of Compound (C-2))
In a 500 ml three-necked flask equipped with a calcium chloride tube, 2-oxabicyclo [3,2,0] heptan-7-one (as described in Tetrahedron Asymmetry, vol4, No6, 1341-1352 (1993)). Synthesis) 10.0 g (139 mmol) and 22 g of sodium hydrogen carbonate were dissolved in 1.4 liters of dichloromethane, and 28 g of a metachloroperbenzoic acid solution having a concentration of 55% by mass was added thereto. Next, this solution was stirred with a magnetic stirrer for 3 hours, and then 1 liter of a 10% by mass aqueous sodium hydrogen carbonate solution and then 1 liter of a saturated aqueous sodium hydrogen carbonate solution were added thereto to precipitate a precipitate. The resulting precipitate was purified by silica gel column chromatography using pentane / ethyl acetate as an eluent to obtain a white crystalline compound (C-2).
Using the same method, other components (C) were synthesized.

Synthesis Example 2 (Synthesis of resin (B1))
Under a nitrogen stream, 20 g of a 6/4 (mass ratio) mixed solvent of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether was placed in a three-necked flask and heated to 80 ° C. (solvent 1). γ-butyrolactone methacrylate, hydroxyadamantane methacrylate, 2-methyl-2-adamantyl methacrylate in a mixed solvent of 6/4 (mass ratio) of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether in a molar ratio of 45/35/35 It melt | dissolved and the 22 mass% monomer solution (200g) was prepared. Furthermore, 8 mol% of initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the monomer, and the dissolved solution was added dropwise to (solvent 1) over 6 hours. After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then poured into 1800 ml of hexane / 200 ml of ethyl acetate, and the precipitated powder was collected by filtration and dried to obtain 37 g of Resin (B1). The resin (B1) obtained had a weight average molecular weight of 9700 and a dispersity (Mw / Mn) of 1.81.
Similarly, resins (B2) to (B27) were synthesized.

  Hereinafter, the structures, weight average molecular weights (Mw), and dispersities (Mw / Mn) of the resins (B1) to (B27) are shown.

Examples 1-14 and Comparative Examples 1-3
<Resist preparation>
The components shown in Table 1 below were dissolved in a solvent to prepare a solution having a solid content concentration of 6% by mass, and this was filtered through a 0.05 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist solution was evaluated by the following method, and the results are shown in Table 1.

  Abbreviations in Table 1 are as follows.

[Basic compounds]
N-1: N, N-dibutylaniline N-2: 2,6-diisopropylaniline N-3: Diazabicyclo [4.3.0] nonene N-4: 2,4,5-triphenylimidazole N-5: 4-dimethylaminopyridine N-6: trioctylamine N-7: dicyclohexylmethylamine N-8: N-phenyldiethanolamine

[Surfactant]
W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.)
(Fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.)
(Silicon)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)

〔solvent〕
SL-1: Propylene glycol monomethyl ether acetate SL-2; 2-heptanone SL-3: Ethyl lactate SL-4: Propylene glycol monomethyl ether SL-5; Cyclohexanone SL-6: γ-butyrolactone

  [Comparative compound]

<Resist evaluation>
ARC29A manufactured by Brewer Science Co., Ltd. was uniformly applied to a silicon wafer with a spin coater at 78 nm, and heat-dried at 205 ° C. for 60 seconds to form an antireflection film. Thereafter, each positive resist solution immediately after preparation was applied by a spin coater and dried (PB) at 115 ° C. for 90 seconds for 60 seconds to form a 150 nm resist film.
This resist film is exposed with an ArF excimer laser stepper (PAS5500 / 1100 NA = 0.75 (2/3 annular illumination) manufactured by ASML) and a halftone phase shift mask through a mask, immediately after exposure and immediately after exposure. Heated (PEB) on a hot plate at 120 ° C. for 60 seconds. Further, the resist film was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a resist pattern.

(Pattern profile)
The profile at the optimum exposure dose was observed with a scanning electron microscope (SEM).

(Pattern collapse)
The exposure amount that reproduces the 80 nm line and space 1/1 mask pattern is the optimum exposure amount, and the exposure amount is increased from the optimum exposure amount. The width was defined as the pattern collapse line width. A smaller value indicates that a finer pattern is resolved without falling, and that pattern falling is less likely to occur.

(Line edge roughness)
The line edge edge roughness is measured by using a length-measuring scanning electron microscope (SEM) to observe a line-and-space 1/1 pattern of 80 nm, and the edge of the line pattern in the longitudinal direction should have an edge of 5 μm. The distance from the reference line was measured by 50 points using a length measurement SEM (Hitachi, Ltd. S-9260), the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.

(Development defects)
In the same manner as in the evaluation of pattern collapse, an 80 nm line and space 1/1 pattern was formed. The number of development defects was measured using an intelligent line monitor 2360 manufactured by KLA Tencor.

(Exposure latitude)
The exposure amount that reproduces the 80 nm line and space 1/1 mask pattern is the optimum exposure amount, and the exposure amount width that reproduces the line width of 80 nm ± 10% is divided by the optimum exposure amount value as a percentage (%). expressed. The larger the numerical value, the smaller the line width variation with respect to the exposure amount change.

  As shown in Table 1, each of the resist compositions of the present invention has an extremely small number of development defects, and the line edge roughness is greatly reduced. Furthermore, satisfactory results have been obtained with respect to pattern collapse and exposure latitude. On the other hand, in the system to which the lactone compounds represented by (C′-1) and (C′-2) are added, development defects, line edge roughness, and pattern collapse are inferior to the lactone compound of the present invention (Comparative Example). 1 and 2). Further, in a system in which no lactone compound is added, development defects, line edge roughness, and pattern collapse are considerably inferior compared with the lactone compound of the present invention (Comparative Example 3).

(Immersion exposure)
<Resist preparation>
The components of Examples 1 to 14 in Table 1 were dissolved in a solvent to prepare a solution having a solid content concentration of 7% by mass, and this was filtered through a 0.03 μm polyethylene filter to prepare a positive resist solution. The adjusted positive resist solution was evaluated by the following method.
<Resolution evaluation>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied onto a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. A positive resist solution prepared thereon was applied and baked at 115 ° C. for 60 seconds to form a 150 nm resist film. The wafer thus obtained was subjected to two-beam interference exposure (wet exposure) using pure water as the immersion liquid. In the two-beam interference exposure (wet), as shown in FIG. 1, a laser 1, an aperture 2, a shutter 3, three reflecting mirrors 4, 5, 6 and a condenser lens 7 are used, and a prism 8, liquid The wafer 10 having an antireflection film and a resist film was exposed through an immersion liquid (pure water) 9. The wavelength of the laser 1 was 193 nm, and the prism 8 forming a 65 nm line and space pattern was used. Immediately after the exposure, the resist pattern obtained by heating at 115 ° C. for 90 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 60 seconds, rinsing with pure water, and spin drying is then applied to the scanning pattern. It observed using the microscope (Hitachi S-9260). When the positive resist solutions of Examples 1 to 13 were used, the 65 nm line and space pattern was resolved without causing pattern collapse.
It is apparent that the composition of the present invention has a good image forming ability even in an exposure method using an immersion liquid.

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

Explanation of symbols

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

Claims (2)

(A) a compound that generates an acid upon irradiation with an actinic ray or radiation,
A positive resist comprising (B) a resin which is decomposed by the action of an acid and increases the solubility in an alkaline developer, and (C) a low molecular compound having a lactone structure represented by the following general formula (C1) Composition.

In general formula (C1),
L ₁ represents an organic group necessary for forming a ring structure with two carbon atoms in the lactone ring in the general formula (C1).
R ₁ and R ₂ each independently represents a hydrogen atom, an organic group or a hydroxyl group. R ₁ and R ₂ may combine with each other to form a ring.   A pattern forming method comprising the steps of: forming a resist film from the positive resist composition according to claim 1; and exposing and developing the resist film.

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