JP4857218B2 - Positive photosensitive composition and pattern forming method using the same - Google Patents

Description

  The present invention relates to a positive photosensitive composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photofabrication processes, and a pattern forming method using the same. is there. More specifically, the present invention relates to a positive photosensitive composition suitable for use as an exposure light source such as far ultraviolet rays of 250 nm or less, preferably 220 nm or less, and an irradiation source using an electron beam, and a pattern forming method using the same.

  The chemically amplified photosensitive composition generates an acid in the exposed area by irradiation with radiation such as far ultraviolet light, and the acid-catalyzed reaction causes the solubility of the active radiation irradiated area and non-irradiated area in the developer. This is a pattern forming material for changing the pattern to form a pattern on the substrate.

  When a KrF excimer laser is used as an exposure light source, a resin having a basic skeleton of poly (hydroxystyrene) having a small absorption mainly in the 248 nm region is used as a main component. A pattern is formed, which is a better system than the conventional naphthoquinone diazide / novolak resin system.

On the other hand, when a further short wavelength light source, for example, ArF excimer laser (193 nm) is used as the exposure light source, the compound having an aromatic group essentially shows a large absorption in the 193 nm region. It wasn't.
For this reason, an ArF excimer laser resist containing a resin having an alicyclic hydrocarbon structure has been developed. Various improvements have been made in resists for ArF excimer lasers. For example, in Patent Document 1, Patent Document 2, and Patent Document 3, in a repeating unit having an alicyclic acid-decomposable group, the main chain and acid decomposition are performed. Various properties have been improved by introducing a repeating unit having a spacer moiety between the sex groups.
However, from the viewpoint of overall performance as a resist, it is actually difficult to find an appropriate combination of resins, photoacid generators, additives, solvents, etc. to be used, and the line width is 100 nm or less. When forming such a fine pattern, even if the resolution performance is excellent, the formed line pattern collapses, and the pattern collapse problem that causes defects during device manufacturing, and the line pattern line It was extremely difficult to satisfy multiple performances such as edge roughness performance and good pattern profile at the same time, and improvements were required.
Here, the line edge roughness means that the resist line pattern and the edge of the substrate interface exhibit irregular shapes in a direction perpendicular to the line direction due to the characteristics of the resist. When this pattern is observed from directly above, the edges appear to be uneven (± several nm to several tens of nm). Since the unevenness is transferred to the substrate by an etching process, if the unevenness is large, an electrical characteristic defect is caused and the yield is lowered.
On the other hand, the thermal flow process is a method in which after a resist pattern is formed by a normal lithography technique, the resist pattern is subjected to heat treatment to reduce the pattern size. The resist pattern is softened by heating after pattern formation, and the size of the part where the pattern is not formed (hole diameter of the hole pattern, space width of the line and space pattern, etc.) can be reduced by flowing in the gap direction of the pattern. Is possible. However, in resist compositions used in conventional ArF excimer laser lithography, etc., the glass transition temperature of the base resin is high, so the softening of the base resin at the heating temperature in the thermal flow process is inadequate. There is a problem that it is difficult to make the resist pattern fine. Patent Document 4 and Patent Document 5 attempt to control the pattern size by introducing a low Tg acid-decomposable group into a resin. However, such a simple low Tg makes it difficult to achieve both resolution and resolution.

JP 2005-331918 A Japanese Patent Laid-Open No. 2004-184637 JP 2003-330192 A JP 2007-114412 A JP 2007-146613 A

  An object of the present invention is to provide a positive photosensitive composition which can improve pattern collapse and line edge roughness performance even in the formation of a fine pattern of 100 nm or less and form a pattern with a good profile, and a pattern forming method using the same. It is to provide. An object of the present invention is to provide a positive photosensitive composition excellent in resist pattern controllability in a thermal flow process, and a pattern forming method using the same.

  The present invention is as follows.

(1) (A) a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) an acid-decomposable repeating unit (b1) represented by the following general formula (I), a cyano group, and a lactone group A positive photosensitive composition comprising a resin having a repeating unit (b2) and increasing the dissolution rate in an alkaline developer by the action of an acid.

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry ₁ represents an alkyl group or a cycloalkyl group.
Z ₁ represents a plurality of atoms necessary for forming an alicyclic hydrocarbon group together with a carbon atom.
Z represents a divalent linking group.

(2) The resin of component (B) is further a -LR ₃ group (wherein L represents a divalent linking group having 4 to 30 carbon atoms, and R ₃ represents a hydrogen atom, a hydroxyl group or an organic group. The positive photosensitive composition as described in (1), which has a repeating unit (b3) having a group).

(3) The positive photosensitive composition as described in (2), wherein the repeating unit (b3) is represented by the following general formula (III).

In general formula (III):
X represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
L represents a divalent linking group having 4 to 30 carbon atoms.
R ₃ represents a hydrogen atom, a hydroxyl group or an organic group.

  (4) The positive type resin according to any one of (1) to (3), wherein the resin as the component (B) further has a repeating unit having at least one kind selected from a hydroxyl group and an alkali-soluble group. Photosensitive composition.

  (5) In the general formula (I), Z is a divalent chain hydrocarbon group or cyclic hydrocarbon group, The positive type according to any one of (1) to (4), Photosensitive composition.

(6) In the general formula (I), the alicyclic hydrocarbon group formed by Z ₁ together with the carbon atom is
The positive photosensitive composition according to any one of (1) to (5), which is selected from an adamantyl group, a norbornyl group, a tetracyclododecanyl group, a cyclohexyl group, and a cyclopentyl group.

  (7) A pattern formation comprising a step of forming a photosensitive film from the positive photosensitive composition according to any one of (1) to (6), and exposing and developing the photosensitive film. Method.

  According to the present invention, there are provided a positive photosensitive composition capable of improving pattern collapse and line edge roughness performance even in the formation of a fine pattern of 100 nm or less and forming a pattern with a good profile, and a pattern forming method using the same. be able to.

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

(A) Compound that generates acid upon irradiation with actinic ray or radiation The positive photosensitive composition of the present invention contains a compound that generates acid upon irradiation with actinic ray or radiation (also referred to as “acid generator”). .
Examples of such an acid generator include a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or an actinic ray or radiation used for a microresist. A known compound that generates an acid by irradiation and a mixture thereof can be appropriately selected and used.

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

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

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

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, compounds represented by the following general formulas (ZI), (ZII), and (ZIII) can be exemplified.

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

  Preferred organic anions include organic anions represented by the following general formulas (AN1) to (AN4).

In general formulas (AN1) to (AN2),
Rc ₁ represents an organic group.
Examples of the organic group for Rc ₁ include those having 1 to 30 carbon atoms, and preferably an alkyl group, an aryl group, or a plurality thereof, which may be substituted, is a single bond, —O—, —CO ₂ —. , —S—, —SO ₃ —, —SO ₂ N (Rd ₁ ) — and the like. Rd ₁ represents a hydrogen atom or an alkyl group, and may form a ring structure with the bonded alkyl group or aryl group.
The organic group of Rc ₁ is more preferably an alkyl group substituted at the 1-position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved. When Rc ₁ has 5 or more carbon atoms, it is preferable that at least one carbon atom has a hydrogen atom, not all hydrogen atoms are substituted with fluorine atoms, and the number of hydrogen atoms is fluorine. More preferably than atoms. By not having a perfluoroalkyl group having 5 or more carbon atoms, ecotoxicity is reduced.

As a particularly preferred embodiment of Rc ₁ , groups represented by the following general formula can be exemplified.

In the above general formula,
Rc ₆ is substituted with a perfluoroalkylene group having 4 or less carbon atoms, more preferably 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms, 3 to 5 fluorine atoms and / or 1 to 3 fluoroalkyl groups. Represents a phenylene group.
Ax represents a linking group (preferably a single bond, —O—, —CO ₂ —, —S—, —SO ₃ —, —SO ₂ N (Rd ₁ ) —). Rd ₁ represents a hydrogen atom or an alkyl group, and may combine with Rc ₇ to form a ring structure.
Rc ₇ represents a hydrogen atom, a fluorine atom, a linear or branched alkyl group, a monocyclic or polycyclic cycloalkyl group or an aryl group. The alkyl group, cycloalkyl group and aryl group may be substituted, but preferably have no fluorine atom as a substituent.

In the general formulas (AN3) to (AN4),
Rc ₃ , Rc ₄ and Rc ₅ each independently represents an organic group.
Preferred examples of the organic group for Rc ₃ , Rc ₄ and Rc ₅ include the same organic groups as those for Rc ₁ .
Rc ₃ and Rc ₄ may combine to form a ring. Examples of the group formed by combining Rc ₃ and Rc ₄ include an alkylene group and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group. By combining Rc ₃ and Rc ₄ to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved, which is preferable.

In the general formula (ZI),
The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1 to 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 a compound (ZI-1) described later.
), (ZI-2) and (ZI-3).

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

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

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or R ₂₀₁
Some of to R ₂₀₃ is an aryl group, the remaining being an alkyl group, or a cycloalkyl radical.
Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.
The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, more preferably a phenyl group or an indole residue. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec- Examples thereof include a butyl group and a t-butyl group.
The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.
The aryl group, alkyl group, and cycloalkyl group of R _{201 to} R ₂₀₃ are an alkyl group (for example, having 1 to 15 carbon atoms), a cycloalkyl group (for example, having 3 to 15 carbon atoms), an aryl group (for example, having 6 to 14 carbon atoms). ), An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group 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 linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, particularly preferably. They are a C1-C4 alkyl group and a C1-C4 alkoxy group. 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.
The arylsulfonium cation is preferably a triphenylsulfonium cation which may be substituted, a naphthyltetrahydrothiophenium cation which may be substituted, or a phenyltetrahydrothiophenium cation which may be substituted.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group containing no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, or an alkoxycarbonylmethyl group, particularly preferably Is a linear, branched 2-oxoalkyl group.

The alkyl group as R ₂₀₁ to R ₂₀₃ is preferably include a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group) . The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, branched 2-oxoalkyl group, more preferably an alkoxymethyl group.
The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl). The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is more preferably a cyclic 2-oxoalkyl group.
Linear as R ₂₀₁ to R _203, branched or cyclic 2-oxoalkyl group may preferably be a group having a 2-position> C = O in the above-described alkyl or cycloalkyl group.
The alkoxy group in the alkoxycarbonylmethyl group as R ₂₀₁ to R _203, preferably may be mentioned alkoxy groups having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, a nitro group, or the like.

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

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Rx and Ry each independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group.
Any two or more of R _1c to R _7c, and R _x and R _y may be bonded to each other to form a ring structure, the ring structure may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond May be included. Examples of the group formed by combining any two or more of R _{1c to} R _7c and R _x and R _y include a butylene group and a pentylene group.
X ⁻ represents a non-nucleophilic anion, and examples thereof include those similar to the non-nucleophilic anion of X ⁻ in formula (I).

The alkyl group as R _{1c to} R _7c is, for example, a linear or branched alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms (for example, a methyl group). , Ethyl group, linear or branched propyl group, linear or branched butyl group, linear or branched pentyl group).
Preferable examples of the cycloalkyl group as R _{1c to} R _7c include a cycloalkyl group having 3 to 8 carbon atoms (for example, 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 as R _x and R _y include the same alkyl groups as R _{1c to} R _7c . The alkyl group as R _x and R _y is more preferably a linear or branched 2-oxoalkyl group or an alkoxymethyl group.
The cycloalkyl group as R _x and R _y may be the same as the cycloalkyl group as R _1c to R _7c. The cycloalkyl group as R _x and R _y is more preferably a cyclic 2-oxoalkyl group.
Examples of the linear or branched alkyl group and the cyclic 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .
R _x and R _y are preferably an alkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more.

In the general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.
The aryl group of R ₂₀₄ to R _207, a phenyl group, a naphthyl group, more preferably a phenyl group.
The alkyl group as R ₂₀₄ to R ₂₀₇ may preferably be mentioned a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group).
The cycloalkyl group as R ₂₀₄ to R ₂₀₇ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
R ₂₀₄ to R ₂₀₇ may have a substituent. The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (I).

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

In the general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₈ represents an alkyl group, a cycloalkyl group, or an aryl group.
R ₂₀₉ and R ₂₁₀ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or an electron-withdrawing group. R ₂₀₉ is preferably an aryl group. R ₂₁₀ is preferably an electron-withdrawing group, and more preferably a cyano group or a fluoroalkyl group.
A represents an alkylene group, an alkenylene group or an arylene group.

  Of the compounds that generate an acid upon irradiation with actinic rays or radiation, more preferred are compounds represented by general formulas (ZI) to (ZIII), and even more preferred are compounds represented by general formula (ZI). And particularly preferred are compounds represented by the general formulas (ZI-1) to (ZI-3).

  Furthermore, the compound which generate | occur | produces the acid represented by the following general formula (AC1)-(AC3) by irradiation of actinic light or a radiation is preferable.

In the general formulas (AC1) to (AC3), Rc ₁ and Rc _{3 to} Rc ₅ represent the general formula (AN1)
Are the same as Rc ₁ and Rc _{3 to} Rc _{5 in} (AN4).

A particularly preferred embodiment of the acid generator is a compound in which, in the structure of the general formula (ZI), X ⁻ is an anion selected from the above (AN1), (AN3), and (AN4).

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

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

(B) Resin whose dissolution rate in an alkaline developer is increased by the action of an acid The resin used in the positive photosensitive composition of the present invention whose dissolution rate in an alkaline developer is increased by the action of an acid is represented by the following general formula ( A resin (also referred to as “resin of component (B)”) having an acid-decomposable repeating unit (b1) represented by I) and a repeating unit (b2) having a cyano group and a lactone group.

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry ₁ represents an alkyl group or a cycloalkyl group.
Z ₁ represents a plurality of atoms necessary for forming an alicyclic hydrocarbon group together with a carbon atom.
Z represents a divalent linking group.

In general formula (I), the alkyl group of Xa ₁ may be substituted with a hydroxyl group or a halogen atom.
Xa ₁ is preferably a hydrogen atom or a methyl group.
The alkyl group of Ry ₁ may be linear or branched, and preferably has 1 to 8 carbon atoms.
More preferably, it is 1-4, and a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a t-butyl group are mentioned, More preferably, they are a methyl group and an ethyl group.
As the cycloalkyl group of Ry ₁ , a cyclopentyl group and a cyclohexyl group are preferable.
The alicyclic hydrocarbon group formed by Z ₁ together with the carbon atom is preferably one having 5 to 20 carbon atoms, more preferably an adamantyl group, a norbornyl group, a tetracyclodokecanyl group, a cyclohexyl group, or a cyclopentyl group. .
The divalent linking group for Z is preferably a divalent linking group having 1 to 20 carbon atoms, more preferably a linear alkylene group having 1 to 8 carbon atoms or a cycloalkylene group having 5 to 20 carbon atoms. The alkylene chain may have a hetero atom such as an oxygen atom, a sulfur atom, an ester group or a ketone group. The chain alkylene group is preferably a chain alkylene group having 1 to 4 carbon atoms, and particularly preferably —CH ₂ —, —CH ₂ CH ₂ —, —CH (CH ₃ ) —, —C (CH _{3). 2} ) The cycloalkylene group is preferably a cyclopentylene group, a cyclohexylene group, an adamantylene group or a norbornylene group. It is preferable that the chain alkylene part of Z does not have acid detachability.

The polymerizable compound for forming the repeating unit represented by the general formula (I) can be easily synthesized by a known method. For example, using a method similar to the method described in JP-A-2005-331918, as shown in the following formula, an alcohol and a carboxylic acid halide compound are reacted under basic conditions, and then this and a carboxylic acid compound are converted into a base. It can be synthesized by reacting under sexual conditions.

  Although the preferable specific example of the repeating unit (b1) represented by general formula (I) is shown below, this invention is not limited to this.

  The repeating unit (b1) represented by the general formula (I) is decomposed by the action of an acid to generate a carboxyl group, and the dissolution rate in an alkali developer increases.

  The resin of component (B) may have two or more types of repeating units (b1) represented by general formula (I).

The resin as the component (B) may have an acid-decomposable repeating unit other than the acid-decomposable repeating unit (b1) represented by the general formula (I).
The acid-decomposable repeating unit other than the acid-decomposable repeating unit (b1) represented by the general formula (I) is preferably a repeating unit represented by the following general formula (II).

In general formula (II):
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom, and is the same as Xa _{1 in} the general formula (I).
Rx _{1 to} Rx ₃ each independently represents an alkyl group or a cycloalkyl group. Rx ₁ ~
At least two binding of rx _3, may form a cycloalkyl group.

In general formula (II), the alkyl group represented by Rx _{1 to} Rx ₃ may be linear or branched, and may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, or an isobutyl group. A group having 1 to 4 carbon atoms such as a t-butyl group is preferable.
The cycloalkyl group of Rx _{1 to} Rx ₃ is a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group or an adamantyl group. Is preferred.
The cycloalkyl group formed by bonding at least two of Rx _{1 to} Rx ₃ includes a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, and a tetracyclododecanyl group. And a polycyclic cycloalkyl group such as an adamantyl group is preferred.
It is preferable that Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are bonded to form the monocyclic or polycyclic cycloalkyl group described above.

  Although the specific example of the repeating unit which has a preferable acid-decomposable group is shown below, this invention is not limited to this.

  Preferred repeating units of the general formula (II) are repeating units of 1, 2, 10, 11, 12, 13, and 14 in the above specific examples.

  When the acid-decomposing repeating unit (b1) of the general formula (I) is used in combination with another acid-decomposing repeating unit (preferably the repeating unit of the general formula (II)), the acid-decomposing repeating unit (b1) of the general formula (I) The ratio of the other acid-decomposing repeating units is 90:10 to 10:90, more preferably 80:20 to 20:80 in terms of molar ratio.

  (B) As for content of all the acid-decomposable repeating units in resin of a component, 20-50 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 25-45 mol%.

The resin of component (B) further has a repeating unit (b2) having a cyano group and a lactone group.
As the lactone group in the repeating unit (b2) having a cyano group and a lactone group, any group can be used as long as it has a lactone structure, but it is preferably a group containing a 5- to 7-membered lactone structure. Yes, those in which other ring structures are condensed in a form that forms a polycyclic structure or a spiro structure in a 5- to 7-membered lactone structure. A group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16) is more preferable. Further, a group having a lactone structure may be directly bonded to the main chain. Preferable lactone structures are general formulas (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure By using, line edge roughness and development defects are improved.
The cyano group contained in the same repeating unit as the lactone group may be bonded to the lactone ring, may be bonded to the ring structure condensed with the lactone, Although it may be bonded to the site, at least one of the substituents (Rb ₂ ) described later is preferably a cyano group. More preferably, the cyano group is bonded to the lactone ring.

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

  Examples of the repeating unit having a group having a lactone structure represented by any of the general formulas (LC1-1) to (LC1-16) include 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 (preferably 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 represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent group obtained by combining these. A linking group represented by a single bond or —Ab ₁ —CO ₂ — is preferable. In the formula, Ab ₁ represents a linear, branched alkylene group or a monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group, or a norbornylene group.
V represents a group represented by any one of the general formulas (LC1-1) to (LC1-16).

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

  The content of the repeating unit (b2) having a cyano group and a lactone group is preferably from 15 to 60 mol%, more preferably from 20 to 50 mol%, still more preferably from 30 to 50 mol%, based on all repeating units in the polymer. .

  Specific examples of the repeating unit (b2) having a cyano group and a lactone group are given below, but the present invention is not limited to these. The methacrylate repeating unit in the specific example can be preferably used even if it is replaced with an acrylate repeating unit.

  Particularly preferred repeating units (b2) having a cyano group and a lactone group include repeating units represented by the following general formula. By selecting the optimum lactone structure, the pattern profile and the density dependence become good.

  In the formula, Rx represents a hydrogen atom, an alkyl group, a halogen atom, or a hydroxymethyl group.

The resin of component (B) may further have a repeating unit having a lactone structure and not having a cyano group. Examples of such a repeating unit include a repeating unit having a lactone structure represented by the general formulas (LC1-1) to (LC1-16) and having no cyano group.

The resin of component (B) is further a -LR ₃ group (wherein L represents a divalent linking group having 4 to 30 carbon atoms, and R ₃ represents a hydrogen atom, a hydroxyl group or an organic group. It is preferable to have a repeating unit (b3) having).

The divalent linking group having 4 to 30 carbon atoms of L is preferably a linear or branched alkylene group having 4 to 30 carbon atoms, and more preferably a linear or branched alkylene group having 4 to 20 carbon atoms.
The alkylene group may have a structure having an oxygen atom, a sulfur atom or an ester group in the alkylene chain, that is, a structure in which an alkylene group is bonded via an oxygen atom, a sulfur atom or an ester group.
Examples of the divalent linking group having 4 to 30 carbon atoms of L include (—CH ₂ —) _n (wherein n represents an integer of 4 to 30), (—CH ₂ —CH (Ra) -O-) _m -La- (wherein _m represents an integer of 1 to 15, Ra represents a hydrogen atom or an alkyl group (preferably a methyl group), and La represents a single bond or an alkylene group (preferably a carbon number). 2 to 28)).
In addition, the carbon atom of the ester bond is not included in the carbon number of 4 to 30 in the divalent linking group having 4 to 30 carbon atoms.
As the organic group for R ₃ , a carboxyl group, a cycloalkyl group, and the like can be used, and a carboxyl group is particularly preferable.

  The repeating unit (b3) is preferably represented by the following general formula (III).

In general formula (III):
X represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
L represents a divalent linking group having 4 to 30 carbon atoms.
R ₃ represents a hydrogen atom, a hydroxyl group or an organic group.

The alkyl group of X is preferably an alkyl group having 1 to 5 carbon atoms and may be substituted with a hydroxyl group or a halogen atom.
The divalent linking group having 4 to 30 carbon atoms of L is preferably a linear or branched alkylene group having 4 to 30 carbon atoms, and more preferably a linear or branched alkylene group having 4 to 20 carbon atoms.
The alkylene group may have a structure having an oxygen atom, a sulfur atom or an ester group in the alkylene chain, that is, a structure in which an alkylene group is bonded via an oxygen atom, a sulfur atom or an ester group.
Examples of the divalent linking group having 4 to 30 carbon atoms of L include (—CH ₂ —) _n (wherein n represents an integer of 4 to 30), (—CH ₂ —CH (Ra) -O-) _m -La- (wherein m is 1 to
15 represents an integer, Ra represents a hydrogen atom or an alkyl group (preferably a methyl group), and La represents a single bond or an alkylene group (preferably having a carbon number of 2 to 28).
In addition, the carbon atom of the ester bond is not included in the carbon number of 4 to 30 in the divalent linking group having 4 to 30 carbon atoms.
As the organic group for R ₃ , a carboxyl group, a cycloalkyl group, and the like can be used, and a carboxyl group is particularly preferable.

  Specific examples of the repeating unit (b3) represented by the general formula (III) are shown below, but the present invention is not limited thereto.

  As for content of a repeating unit (b3), 1-40 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 1-30 mol%, More preferably, it is 5-20 mol%.

  The resin as the component (B) can have a repeating unit having a hydroxyl group or a cyano group. This improves the substrate adhesion and developer compatibility. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group. As the alicyclic hydrocarbon structure substituted with a preferred hydroxyl group or cyano group, partial structures represented by the following general formulas (VIIa) to (VIId) are preferred.

In general formulas (VIIa) to (VIIc),
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom. In general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the remaining are hydrogen atoms.

  Examples of the repeating unit having a partial structure represented by the general formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the general formulas (AIIa) to (AIIb),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.

  The content of the repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably 0 to 40 mol%, more preferably 0 to 30 mol%, still more preferably 5 with respect to all repeating units in the polymer. ˜25 mol%.

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

  The resin of component (B) preferably has a repeating unit having an alkali-soluble group. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol (for example, hexafluoroisopropanol group) substituted with an electron-attracting group at the α-position. It is more preferable to have a repeating unit. By containing the repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is used at the time of polymerization and introduced at the end of the polymer chain, and the linking group is monocyclic or polycyclic. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  As for content of the repeating unit which has an alkali-soluble group, 1-20 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 3-15 mol%, More preferably, it is 5-10 mol%.

  Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto.

  The resin of component (B) may further contain a repeating unit that has an alicyclic hydrocarbon structure and does not exhibit 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, diamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like.

  In addition to the above repeating structural unit, the resin of component (B) is dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required properties of resist, such as resolution, heat resistance, and sensitivity. Various repeating structural units can be included for the purpose of adjusting the above.

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

Thereby, the performance required for the resin of the component (B), 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.

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

  In the component (B) resin, the molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist performance required for resolving power and heat resistance. In order to adjust the sensitivity and the like, it is set as appropriate.

  When the positive photosensitive composition of the present invention is used for ArF exposure, the resin of component (B) preferably has no aromatic group from the viewpoint of transparency to ArF light.

  As the resin of component (B), preferably, all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Can be used.

The resin of component (B) 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 photosensitive composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.
The weight average molecular weight of the resin of component (B) is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, and most preferably 5,000 to as a polystyrene equivalent value by GPC method. 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 degree of dispersion (molecular weight distribution) is usually from 1 to 5, preferably from 1 to 3, more preferably from 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 photosensitive composition of the present invention, the blending amount of the resin as the component (B) in the entire composition is preferably 50 to 99.9% by mass, more preferably 60 to 99.0% by mass in the total solid content. %.
In the present invention, the resin of component (B) may be used alone or in combination.

Dissolution control compound having a molecular weight of 3000 or less having at least one selected from an alkali-soluble group, a hydrophilic group and an acid-decomposable group. The positive photosensitive composition of the present invention comprises an alkali-soluble group, a hydrophilic group and an acid-decomposable group. A dissolution controlling compound having a molecular weight of 3000 or less (hereinafter also referred to as “solubility controlling compound”) having at least one selected from
Examples of the dissolution control compound include a carboxyl group, a sulfonylimide group, a compound having an alkali-soluble group such as a hydroxyl group substituted at the α-position with a fluoroalkyl group, a hydroxyl group, a lactone group, a cyano group, an amide group, a pyrrolidone group, a sulfone group. A compound having a hydrophilic group such as an amide group or a compound having an acid-decomposable group is preferred. The acid-decomposable group is preferably a group in which a carboxyl group or a hydroxyl group is protected with an acid-decomposable protecting group. In order not to lower the permeability of 220 nm or less as the dissolution control compound, it is preferable to use a compound that does not contain an aromatic ring, or to use a compound having an aromatic ring in an amount of 20 wt% or less based on the solid content of the composition.
Preferred dissolution control compounds include carboxylic acid compounds having an alicyclic hydrocarbon structure such as adamantane (di) carboxylic acid, norbornane carboxylic acid, and cholic acid, or compounds obtained by protecting the carboxylic acid with an acid-decomposable protecting group, such as saccharides. A polyol or a compound having its hydroxyl group protected with an acid-decomposable protecting group is preferred.

  The molecular weight of the dissolution controlling compound is 3000 or less, preferably 300 to 3000, and more preferably 500 to 2500.

  The addition amount of the dissolution control compound is preferably 3 to 40% by mass, more preferably 5 to 20% by mass, based on the solid content of the positive photosensitive composition.

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

Basic Compound The positive photosensitive composition of the present invention contains a basic compound in order to reduce the change in performance over time from exposure to heating or to control the diffusibility of the acid generated by exposure in the film. Is preferred.

Examples of basic compounds include nitrogen-containing basic compounds and onium salt compounds.
Preferred examples of the structure of the nitrogen-containing basic compound include compounds having partial structures represented by the following general formulas (A) to (E).

In general formula (A),
R ^250, R ²⁵¹ and R ²⁵² are each independently a hydrogen atom, an alkyl having 1 to 20 carbon atoms, a cycloalkyl group or an aryl group having 6 to 20 carbon atoms having 3 to 20 carbon atoms, R ²⁵⁰ and R ²⁵¹ may be bonded to each other to form a ring. These may have a substituent. Examples of the alkyl group and cycloalkyl group having a substituent include an aminoalkyl group having 1 to 20 carbon atoms, an aminocycloalkyl group having 3 to 20 carbon atoms, and 1 carbon atom. A -20 hydroxyalkyl group or a C3-C20 hydroxycycloalkyl group is preferred.
These may contain an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain.
In general formula (E),
R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ each independently represent an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms.

  Preferable compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, and piperidine, and may have a substituent. More preferable compounds include compounds having an imidazole structure, a diazabicyclo structure, an onium hydroxide structure, an onium carboxylate structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, a hydroxyl group and / or Or the aniline derivative which has an ether bond etc. can be mentioned.

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

  These basic compounds are used alone or in combination of two or more. The usage-amount of a basic compound is 0.001-10 mass% normally based on solid content of a positive photosensitive composition, Preferably it is 0.01-5 mass%. In order to obtain a sufficient addition effect, 0.001% by mass or more is preferable, and 10% by mass or less is preferable in terms of sensitivity and developability of the non-exposed area.

Fluorine and / or silicon surfactant The positive photosensitive composition of the present invention further comprises fluorine and / or silicon surfactant (fluorine surfactant, silicon surfactant, fluorine atom and silicon atom It is preferable to contain either one or two or more surfactants containing both.
When the positive photosensitive composition of the present invention contains fluorine and / or a silicon-based surfactant, adhesion and development defects are obtained with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. It is possible to provide a resist pattern with less.

  Examples of these fluorine and / or silicon surfactants include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

  In addition to the known surfactants described above, surfactants are derived from fluoroaliphatic compounds produced by the telomerization method (also referred to as the telomer method) or the oligomerization method (also referred to as the oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.

  As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. It may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxy) (Ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

  The amount of fluorine and / or silicon-based 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 photosensitive composition (excluding the solvent). %.

Solvent The positive photosensitive composition of the present invention is used by dissolving each component in a predetermined solvent.
Examples of solvents that can be used include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether. Acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N- Examples include organic solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and tetrahydrofuran. Kill.

In the present invention, the solvent may be used alone or mixed, but it is preferable to use a mixed solvent containing two or more kinds of solvents having different functional groups. As a result, the solubility of the material is increased, and not only the generation of particles over time can be suppressed, but also a good pattern profile can be obtained. Preferable functional groups contained in the solvent include ester groups, lactone groups, hydroxyl groups, ketone groups, and carbonate groups. As the mixed solvent having different functional groups, the following mixed solvents (S1) to (S5) are preferable.
(S1) a mixed solvent obtained by mixing a solvent containing a hydroxyl group and a solvent not containing a hydroxyl group,
(S2) a mixed solvent obtained by mixing a solvent having an ester structure and a solvent having a ketone structure;
(S3) a mixed solvent obtained by mixing a solvent having an ester structure and a solvent having a lactone structure;
(S4) a mixed solvent obtained by mixing a solvent having an ester structure, a solvent having a lactone structure, and a solvent containing a hydroxyl group;
(S5) A mixed solvent containing a solvent having an ester structure, a solvent having a carbonate structure, and a hydroxyl group.
As a result, the generation of particles during storage of the resist solution can be reduced, and the generation of defects during application can be suppressed.

Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone and cyclohexanone are particularly preferred.
Examples of the solvent having a ketone structure include cyclohexanone and 2-heptanone, and cyclohexanone is preferable.
Examples of the solvent having an ester structure include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, and butyl acetate, and propylene glycol monomethyl ether acetate is preferable.
Examples of the solvent having a lactone structure include γ-butyrolactone.
Examples of the solvent having a carbonate structure include propylene carbonate and ethylene carbonate, with propylene carbonate being preferred.

The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a ketone structure is 1/99 to 99/1, preferably 10/90 to 90/10, and more preferably 40/60 to 80/20. . A mixed solvent containing 50% by mass or more of a solvent having an ester structure is particularly preferable from the viewpoint of coating uniformity.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a lactone structure is 70/30 to 99/1, preferably 80/20 to 99/1, and more preferably 90/10 to 99/1. . A mixed solvent containing 70% by mass or more of a solvent having an ester structure is particularly preferable from the viewpoint of stability over time.
When mixing a solvent having an ester structure, a solvent having a lactone structure, and a solvent containing a hydroxyl group, the solvent having an ester structure is 30 to 80% by mass, the solvent having a lactone structure is 1 to 20% by mass, and the hydroxyl group is contained. It is preferable to contain 10-60 mass% of solvent to do.
When mixing a solvent having an ester structure, a solvent having a carbonate structure, and a solvent containing a hydroxyl group, the solvent having an ester structure is 30 to 80% by mass, the solvent having a carbonate structure is 1 to 20% by mass, and the hydroxyl group is contained. It is preferable to contain 10-60 mass% of solvent to do.

A preferable embodiment of these solvents is a solvent containing an alkylene glycol monoalkyl ether carboxylate (preferably propylene glycol monomethyl ether acetate), more preferably a mixed solvent of an alkylene glycol monoalkyl ether carboxylate and another solvent. And the other solvent is at least one solvent selected from solvents having at least one functional group selected from a hydroxyl group, a ketone group, a lactone group, an ester group, an ether group, and a carbonate group. A particularly preferable mixed solvent is a mixed solvent of at least one selected from ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether, butyl acetate, and cyclohexanone, and propylene glycol monomethyl ether acetate.
The development defect performance can be improved by selecting an optimum solvent.

<Other additives>
The positive photosensitive composition of the present invention has further solubility in a dye, a plasticizer, a surfactant other than the fluorine and / or silicon surfactant, a photosensitizer, and a developer as necessary. A compound to be promoted and the like can be contained.

  The dissolution accelerating compound for the developer that can be used in the present invention is a low molecular weight compound having a molecular weight of 1,000 or less and having two or more phenolic OH groups or one or more carboxy groups. When it has a carboxy group, an alicyclic or aliphatic compound is preferable.

A preferable addition amount of these dissolution promoting compounds is 2 to 50% by mass, and more preferably 5 to 30% by mass with respect to the acid-decomposable resin. 50 mass% or less is preferable at the point of development residue suppression and the pattern deformation prevention at the time of image development.

  Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to methods described in, for example, JP-A-4-1222938, JP-A-2-28531, U.S. Pat. No. 4,916,210, European Patent 219294, and the like. Can be easily synthesized.

  Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

  In the present invention, other surfactants than fluorine and / or silicon surfactants can be added. Specifically, nonionic interfaces such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan aliphatic esters, polyoxyethylene sorbitan aliphatic esters, etc. Mention may be made of activators.

  These surfactants may be added alone or in some combination.

(Pattern formation method)
The positive photosensitive composition of the present invention is used by dissolving each component in a predetermined 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 photosensitive composition is coated on a substrate (eg, silicon / silicon dioxide coating) used in the manufacture of precision integrated circuit elements by a suitable coating method such as a spinner or coater, dried, and photosensitive. A film is formed.
The photosensitive film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.
Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the photosensitive film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred. Further, an overcoat layer may be further provided on the photosensitive film so that the immersion medium and the photosensitive film do not come into direct contact with each other during the immersion exposure. Thereby, elution of the composition from the photosensitive film to the immersion medium is suppressed, and development defects are reduced.

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

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. Examples of the alkaline developer of the positive photosensitive composition include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia and other inorganic alkalis, ethylamine, n-propylamine and the like. Secondary amines such as amines, diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxy Alkaline aqueous solutions such as quaternary ammonium salts such as pyrrole and 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 resin (RA-1))
Under a nitrogen stream, 10.6 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. The following monomer (A) 14.8g, monomer (B) 11.7g, polymerization initiator V-60 (manufactured by Wako Pure Chemical Industries, Ltd.) 13 mol% with respect to the monomer were dissolved in 96 g of cyclohexanone. It was added dropwise over time. 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 added dropwise to a mixed solution of 900 m of methanol / 100 ml of water over 20 minutes. The precipitated powder was collected by filtration and dried to obtain 20 g of Resin (RA-1). The weight average molecular weight of the obtained resin (RA-1) was 7200 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.65.

  Other resins were synthesized using the same method. The weight average molecular weight was adjusted by changing the amount of the polymerization initiator.

  Hereinafter, the structure of the acid-decomposable resin used in Examples and Comparative Examples is shown.

Examples 1-16 and Comparative Examples 1-2
<Resist preparation>
Components shown in Tables 1 and 2 below were dissolved in a solvent to prepare a solution having a solid concentration of 8% by mass, and this was filtered through a 0.03 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist solution was evaluated by the following method, and the results are also shown in Tables 1 and 2.
<Resist evaluation>
An antireflection film DUV-42 manufactured by Brewer Science Co., Ltd. was uniformly applied to 600 angstroms on a silicon substrate that had been subjected to hexamethyldisilazane treatment with a spin coater.
After drying at 0 ° C. for 90 seconds on a hot plate, heat drying was performed at 190 ° C. for 240 seconds. Thereafter, each positive resist solution was applied by a spin coater and dried at 120 ° C. for 60 seconds to form a 160 nm resist film.
The resist film was exposed with an ArF excimer laser stepper (NA = 0.75, dipole manufactured by ASML) through a mask, and heated on a hot plate at 120 ° C. for 60 seconds immediately after the exposure. Further, the resist film was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 30 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a line pattern.

Pattern collapse evaluation method:
When the exposure amount that reproduces the mask pattern of 75 nm line and space is the optimum exposure amount, and the line width of the line pattern formed by further increasing the exposure amount from the optimum exposure amount is reduced, the pattern does not collapse It was defined by the line width to be resolved. A smaller value indicates that a finer pattern is resolved without falling, and pattern falling is less likely to occur.
Line edge edge roughness evaluation method:
In measuring the line edge edge roughness, a length measuring scanning electron microscope (SEM) is used to observe an isolated pattern of 75 nm, and the distance from the reference line where the edge should be in the range where the longitudinal edge of the line pattern is 2 μm is measured. Ten points were measured with a length measurement SEM (Hitachi, Ltd. S-8840), the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.
Profile evaluation method:
An isolated pattern of 75 nm was observed. A rectangular pattern was indicated by ◯, a slightly tapered pattern was indicated by △, and a film loss was indicated by x.

  The abbreviations in Tables 1 and 2 are shown below.

  [Acid generator]

[Basic compounds]
TPSA: Triphenylsulfonium acetate
DIA: 2,6-diisopropylaniline
TEA: Triethanolamine
DBA: N, N-dibutylaniline
PBI: 2-phenylbenzimidazole TMEA: Tris (methoxyethoxyethyl) amine
PEA: N-phenyldiethanolamine PBMA: 2- [2- {2- (2,2-dimethoxy-phenoxyethoxy) ethyl} -bis- (2-methoxyethyl)]-amine PBMA has 1 corresponding phenoxy group After heating and reacting a primary amine and a haloalkyl ether, an aqueous solution of a strong base such as sodium hydroxide, potassium hydroxide or tetraalkylammonium is added, followed by extraction with an organic solvent such as ethyl acetate or chloroform. be able to.
[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-based) W-4: Troysol S-366 (manufactured by Troy Chemical Co., Ltd.)
〔solvent〕
S1: Propylene glycol methyl ether acetate
S2: 2-Heptanone
S3: cyclohexanone
S4: γ-butyrolactone
S5: Propylene glycol methyl ether
S6: Ethyl lactate S7: Propylene carbonate

  From Tables 1-2, it is clear that the positive photosensitive composition of the present invention has improved pattern collapse, improved line edge roughness performance, and good profile.

(Immersion exposure)
<Resist preparation>
The components of Table 1, Examples 1 to 16 and Comparative Examples 1 and 2 were dissolved in a solvent to prepare a solution having a solid content concentration of 6% by mass, and this was filtered through a 0.03 μm polyethylene filter to obtain a positive resist solution. Prepared. The prepared 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 140 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%) for 60 seconds, rinsing with pure water, and spin drying is then applied to a scanning electron microscope. (Hitachi S-9260) was used for observation. When the compositions of Examples 1 to 16 were used, the 65 nm line and space pattern was resolved without causing pattern collapse. When the compositions of Comparative Examples 1 and 2 were used, the pattern collapse was observed in some patterns although the 65 nm line and space pattern was resolved.
It is clear that the positive photosensitive composition of the present invention has a good image forming ability even in an exposure method using an immersion liquid.

Example 17
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. On top of that, the positive resist solution of Example 10 was applied and baked at 110 ° C. for 60 seconds to form a 160 nm resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser scanner (PAS5500 / 1100, NA0.75, Annular (σo / σi = 0.89 / 0.65) manufactured by ASML). After heating at 110 ° C. for 60 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying gave an 85 nm line and space pattern. .
Subsequently, each was baked at 150 ° C., 160 ° C., and 170 ° C. for 90 seconds, and the shrinkage of the line width was measured by a length measuring SEM (Hitachi, Ltd. S-9260). As a result, shrinkage of 10% or more was observed in baking at 150 ° C., and it was found that the resin of the present invention has thermal flow suitability.

Comparative Example 3
Baking treatment similar to that of Example 17 was performed using the composition of Comparative Example 2 and the shrinkage of the line width was observed. The shrinkage of the line width was 10% or less even at 170 ° C.

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 (7)

(A) a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) an acid-decomposable repeating unit (b1) represented by the following general formula (I), and a repeating unit having a cyano group and a lactone group ( a positive photosensitive composition comprising a resin having a dissolution rate in an alkali developer by the action of an acid.

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry ₁ represents an alkyl group or a cycloalkyl group.
Z ₁ represents a plurality of atoms necessary for forming an alicyclic hydrocarbon group together with a carbon atom.
Z represents a divalent linking group. The resin of component (B) is further a -LR ₃ group (wherein L represents a divalent linking group having 4 to 30 carbon atoms, and R ₃ represents a hydrogen atom, a hydroxyl group or an organic group. The positive photosensitive composition according to claim 1, wherein the positive photosensitive composition has a repeating unit (b3). The positive photosensitive composition according to claim 2, wherein the repeating unit (b3) is represented by the following general formula (III).

In general formula (III):
X represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
L represents a divalent linking group having 4 to 30 carbon atoms.
R ₃ represents a hydrogen atom, a hydroxyl group or an organic group. The positive photosensitive composition according to claim 1, wherein the resin as the component (B) further has a repeating unit having at least one kind selected from a hydroxyl group and an alkali-soluble group.   The positive photosensitive composition according to any one of claims 1 to 4, wherein in the general formula (I), Z is a divalent chain hydrocarbon group or a cyclic hydrocarbon group. In general formula (I), the alicyclic hydrocarbon group formed by Z ₁ together with the carbon atom is selected from an adamantyl group, a norbornyl group, a tetracyclododecanyl group, a cyclohexyl group, and a cyclopentyl group. Item 6. The positive photosensitive composition according to any one of Items 1 to 5.   A pattern forming method comprising a step of forming a photosensitive film from the positive photosensitive composition according to claim 1, and exposing and developing the photosensitive film.

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