JP2008083158A - Positive photosensitive composition and pattern forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photosensitive composition reduced in pattern collapse and line edge roughness even in the formation of a fine pattern of ≤100 nm and capable of forming a pattern of good profile and to provide a pattern forming method using the same, with respect to the positive photosensitive composition for use in the production process of a semiconductor such as IC, in the production of a circuit substrate of liquid crystal, thermal head and the like or in other photofabrication processes and the pattern forming method using the same. <P>SOLUTION: The positive photosensitive composition comprises (A) a compound capable of generating a specific acid upon irradiation with an actinic ray or radiation and (B) a resin having a specific acid decomposable repeating unit and having a rate of dissolution in an alkali developer increased by the action of an acid. The pattern forming method using the same is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

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, an ArF excimer laser (193 nm) is used as an exposure light source, the compound having an aromatic group exhibits 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 resin, photoacid generator, additive, solvent, 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 problem of pattern collapse that causes defects during device manufacturing, and the line edge of the line pattern It was very difficult to satisfy multiple performances such as 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.

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

  The present invention is as follows.

(1) (A) a compound capable of generating an acid represented by the following general formula (II) upon irradiation with actinic rays or radiation; and (B) an acid-decomposable repeating unit represented by the following general formula (I). And a positive photosensitive composition comprising a resin whose rate of dissolution in an alkaline developer is increased 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 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a ring structure.
Z represents a divalent linking group.
In general formula (II):
Rb1 represents an electron-withdrawing group.
Rb2 represents an organic group other than the electron-withdrawing group.
m = 0-5, n = 0-5, m + n ≦ 5
When m is 2 or more, a plurality of Rb1 may be the same or different.
When n is 2 or more, a plurality of Rb2s may be the same or different.

(2) (A) In the general formula (II), m is 1 to 5, and the electron withdrawing group of Rb1 is at least one selected from a fluorine atom, a fluoroalkyl group, a nitro group, an ester group, and a cyano group. The positive photosensitive composition as described in (1) above, wherein

(3) The resin as component (B) further has a repeating unit having at least one selected from a lactone group, a hydroxyl group, a cyano group and an acid group, as described in (1) or (2) above A positive photosensitive composition.
(4) In the general formula (I), any one of the above (1) to (3), wherein Z is a divalent chain hydrocarbon group or a divalent cyclic hydrocarbon group The positive photosensitive composition as described.

(5) In the general formula (II), m = 1 to 5, n = 0 to 5, m + n ≦ 5, and Rb1 or Rb2 contains an alkyl structure having 4 to 20 carbon atoms. The positive photosensitive composition described in 1.
(6) A pattern comprising a step of forming a photosensitive film from the positive photosensitive composition according to any one of (1) to (5) above, and exposing and developing the photosensitive film. Forming 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 an acid represented by the general formula (II) upon irradiation with actinic rays or radiation The positive photosensitive composition of the present invention is represented by the following general formula (II) upon irradiation with actinic rays or radiation. And a compound capable of generating an acid (also referred to as “compound of component (A)”).
Acid represented by general formula (II):

Rb1 represents an electron-withdrawing group.
Rb2 represents an organic group other than the electron-withdrawing group.
m = 0 to 5, n = 0 to 5, and m + n ≦ 5.
When m is 2 or more, a plurality of Rb1 may be the same or different.
When n is 2 or more, a plurality of Rb2s may be the same or different.

m is preferably 1 to 5 or more, and more preferably 2 to 5. By having an electron-withdrawing group, the acidity of the acid generated upon irradiation with actinic rays is increased, and the sensitivity is improved.
The electron withdrawing group in Rb1 is a group having a positive Hammett's substituent constant as the electron withdrawing group. Hammett's substituent constant is defined by the value at the substitution position relative to the sulfo group.
The electron withdrawing group in Rb1 is preferably a fluorine atom, a fluoroalkyl group, a nitro group, an ester group or a cyano group, more preferably a fluorine atom.
The electron withdrawing group as Rb1 preferably has 20 or less carbon atoms.

The organic group as Rb2 is preferably an organic group having 1 to 20 carbon atoms, more preferably 4 to 20 carbon atoms, and still more preferably 4 to 15 carbon atoms. Preferred organic groups include alkyl groups, alkoxy groups, alkylthio groups, acyl groups, acyloxy groups, acylamino groups, alkylsulfonyloxy groups, alkylsulfonylamino groups, and the like. These alkyl chains may have a linking group having a hetero atom. As a preferable linking group having a hetero atom, —C (═O) O—, —C (═O) —, —SO ₂ —, —SO ₃ —, —SO ₂ N (A2) — (A2 is a hydrogen atom) , An optionally substituted alkyl group), -O-, -S-, and the like, and two or more of these may be combined. When two or more are combined, it is preferably via a linking group having no hetero atom such as an alkylene group or an arylene group.
These groups may have a further substituent. Preferred examples of the further substituent include a hydroxyl group, a cyano group, a nitro group, a halogen atom, a carboxyl group, a sulfo group, and a formyl group.

  In the general formula (II), m = 1 to 5, n = 0 to 5, m + n ≦ 5, and Rb1 or Rb2 is preferably a group containing an alkyl structure having 4 to 20 carbon atoms. By containing an alkyl structure having 4 to 20 carbon atoms, the diffusibility of the acid generated by irradiation with actinic rays is suppressed, and the exposure latitude is improved. Examples of the group containing an alkyl structure having 4 to 20 carbon atoms include an alkyl group having 4 to 20 carbon atoms, an alkoxy group, an alkylthio group, an alkylsulfonyl group, an alkylsulfonylamino group, and an ester group having 5 to 21 carbon atoms. .

  The acid represented by the general formula (II) is preferably a benzenesulfonic acid substituted with a fluorine atom and an organic group having 4 to 20 carbon atoms, and more preferably an acid represented by the following general formula (II ′). is there.

Where
Examples of Rb2 in the general formula (II ′) include the same as Rb2 in the general formula (II), preferably an alkyl group having 4 to 20 carbon atoms, an alkoxy group, an alkylthio group, an alkylsulfonyl group, and an alkylsulfonylamino group. is there.
In the general formula (II), m = 1 to 5, n = 0 to 5, m + n ≦ 5, and Rb contains an alkyl structure having 4 to 20 carbon atoms.

Specific examples of the acid represented by the general formula (II) are shown below.

  Specific examples of the acid represented by the general formula (II ′) that are more preferable as the acid represented by the general formula (II) are shown below.

  Examples of the compound that generates an acid represented by the general formula (II) upon irradiation with actinic rays or radiation include, for example, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, and o-nitrobenzyl sulfonates. Can be mentioned.

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

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

  Among the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, compounds represented by the following general formulas (ZIa) and (ZIIa) can be exemplified.

In the above general formula (ZIa), R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
Xd- represents an anion of the acid represented by the general formula (II).
Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (ZI-1a), (ZI-2a) and (ZI-3a) described later.

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

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

Compound (ZI-1a) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZIa), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
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 with the remaining being an alkyl group.
Examples of the arylsulfonium compound include a triarylsulfonium compound, a diarylalkylsulfonium compound, and an aryldialkylsulfonium compound.
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, branched or cyclic alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec. -Butyl group, t-butyl group, cyclopropyl group, cyclobutyl group, cyclohexyl group and the like can be mentioned.
Aryl group R ₂₀₁ to R _203, an alkyl group, an alkyl group (for example, 1 to 15 carbon atoms), an aryl group (e.g., carbon number 6 to 14), an alkoxy group (for example, 1 to 15 carbon atoms), a halogen atom, You may have a hydroxyl group and a phenylthio group as a substituent. Preferred substituents are linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms, linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, most preferably alkyl groups having 1 to 4 carbon atoms, It is 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 an optionally substituted triphenylsulfonium cation, an optionally substituted naphthyltetrahydrothiophenium cation, and an optionally substituted phenyltetrahydrothiophenium cation.

Next, the compound (ZI-2a) will be described.
Compound (ZI-2a) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZIa) 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 2-oxoalkyl group, an alkoxycarbonylmethyl group, an allyl group, or a vinyl group, more preferably a linear, branched, or cyclic 2-oxoalkyl group, An alkoxycarbonylmethyl group, most preferably a linear, branched 2-oxoalkyl group.

The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, branched, or cyclic, preferably a linear or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group).
The 2-oxoalkyl group as R _{201 to} R ₂₀₃ may be linear, branched or cyclic, and preferably includes a group having> C═O at the 2-position of the above alkyl group. it can.
The alkoxy group in the alkoxycarbonylmethyl group as R ₂₀₁ to R _203, preferred examples include an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl 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.
Two members out of R _{201 to} R ₂₀₃ may combine 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).

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

R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom.
R _6c and R _7c represent a hydrogen atom or an alkyl group.
Rx and Ry each independently represents an alkyl group, a 2-oxoalkyl group, an alkoxycarbonylmethyl group, an allyl group, or a vinyl group.
Any two or more of R _{1c to} R _5c , and R _x and R _y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom, a sulfur atom, an ester bond, and an amide bond. May be included.
Xd ^- represents an anion of the acid represented by formula (II).

The alkyl group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms. Group (for example, methyl group, ethyl group, linear or branched propyl group, linear or branched butyl group, linear or branched pentyl group), C3-C8 cyclic alkyl group (for example, cyclopentyl group, 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 either a straight chain of R _1c to R _5c, branched, cyclic alkyl group, or a linear, branched or cyclic alkoxy group, more preferably the sum of the carbon atoms of R _5c from R _1c 2 to 15 It is. 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 _5c .
Examples of the 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group as R _{1c to} R _5c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .
Examples of the group formed by combining R _x and R _y include a butylene group and a pentylene group.

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 (ZIIa) and (ZIIIa), R _{204 to} R ₂₀₇ each independently represents an aryl group which may have a substituent or an alkyl group which may have a substituent.
Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group.
The alkyl group as R _{204 to} R ₂₀₇ may be linear, branched or cyclic, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group). Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, 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), an aryl group (e.g. having 6 to 15 carbon atoms), an alkoxy group (for example, 1 to 15 carbon atoms ), Halogen atoms, hydroxyl groups, phenylthio groups, and the like.

  Of the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, compounds represented by the following general formulas (ZIIIa) and (ZIVa) can be further exemplified.

In general formulas (ZIIIa) and (ZIVa),
Xd represents a monovalent group obtained by removing a hydrogen atom from the acid represented by the general formula (II).
_R207 and _{R208 each} represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or an electron-withdrawing group. R ₂₀₇ is preferably a substituted or unsubstituted aryl group.
R ₂₀₈ is preferably an electron-withdrawing group, more preferably a cyano group or a fluoroalkyl group.
A represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkenylene group, or a substituted or unsubstituted arylene group.

Of the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, more preferably,
Compounds represented by general formulas (ZIa) to (ZIIIa), more preferably compounds represented by (ZIa), and most preferably compounds represented by (ZI-1a) to (ZI-3a) It is.

  Among the components (A), examples of particularly preferable ones are given below.

  (A) The compound of a component 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 component (A) compound in the composition is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, still more preferably 3 to 8%, based on the total solid content of the resist composition. % By mass, particularly preferably 4 to 7% by mass.

The positive photosensitive composition of the present invention is a compound that generates an acid other than the sulfonic acid represented by the general formula (II) upon irradiation with actinic rays or radiation together with the compound of component (A) (hereinafter referred to as “combination use”). Also referred to as “acid generator”).
Preferred examples of the combined acid generator include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In the above general formula (ZI), R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, preferably sulfonate anion, carboxylate anion, bis (alkylsulfonyl) amide anion, tris (alkylsulfonyl) methide anion, BF4-, PF6-, SbF6-, etc. An organic anion containing a carbon atom is preferred.
Preferable organic anions include organic anions represented by the following formulas AN1 to AN4.

Rc1 represents an organic group.
As the organic group for Rc1, an organic group having 1 to 30 carbon atoms is preferably used, and an optionally substituted alkyl group, or a plurality of these may be a single bond, —O—, —CO 2 —, —S—, —SO 3 —. , -SO2N (Rd1)-, and the like. Rd1 represents a hydrogen atom or an alkyl group.
Rd1 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 Rc1 is more preferably an alkyl group substituted at the 1-position 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 Rc1 has 5 or more carbon atoms, at least one carbon atom is preferably substituted with a hydrogen atom, and more preferably, the number of hydrogen atoms is larger than that of fluorine atoms. By not having a perfluoroalkyl group having 5 or more carbon atoms, ecotoxicity is reduced.
The most preferred embodiment of Rc1 is a group represented by the following general formula.

Rc6 is a perfluoroalkylene group.
Ax is a linking group (preferably a single bond, —O—, —CO 2 —, —S—, —SO 3 —, —SO 2 N (Rd 1) —). Rd1 represents a hydrogen atom or an alkyl group, and may combine with Rc7 to form a ring structure.

Rc7: a hydrogen atom, a fluorine atom, a linear, branched, monocyclic or polycyclic alkyl group which may be substituted, or an aryl group which may be substituted. The optionally substituted alkyl group and aryl group preferably do not contain a fluorine atom as a substituent.
Rc3, Rc4 and Rc5 represent an organic group.
Preferred examples of the organic group for Rc3, Rc4, and Rc5 include the same organic groups as those for Rc1.
Rc3 and Rc4 may be bonded to form a ring.
Examples of the group formed by combining Rc3 and Rc4 include an alkylene group and an arylene group. A perfluoroalkylene group having 2 to 4 carbon atoms is preferred. By combining Rc3 and Rc4 to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved, which is preferable.

The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1-30, preferably 1-20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group.
The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.

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

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

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
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 compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

The definitions of R201 to 207 in the compounds (ZI-1) to (ZI-3) are the same as those in the compounds (ZI-1a) to (ZI-3a).
In (ZII) (ZIII), R 204 ~R 207 each independently represents an alkyl group which may have an optionally substituted aryl group or a substituent.
Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group.
The alkyl group as R _{204 to} R ₂₀₇ may be linear, branched or cyclic, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group). Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, 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), an aryl group (e.g. having 6 to 15 carbon atoms), an alkoxy group (for example, 1 to 15 carbon atoms ), Halogen atoms, hydroxyl groups, phenylthio groups, and the like.

  Of the compounds that decompose upon irradiation with actinic rays or radiation that may be used in combination, preferred compounds further include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI). be able to.

In general formula (ZIV), Ar ₃ and Ar ₄ each independently represent a substituted or unsubstituted aryl group. The definitions of Ar ₃ and Ar ₄ , R ₂₀₆ , R ₂₀₇ and R ₂₀₈ , and A in the general formula (ZV) (ZVI) are the same as those in (ZVa) (ZVIa).

Of the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, more preferred are compounds represented by general formulas (ZI) to (ZIII), and even more preferred are compounds represented by (ZI). Most preferred are compounds represented by (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.

  That is, the most preferred embodiment of the component (A) is a compound in which X- is an anion selected from AN1, AN3 and AN4 in the structure of the general formula (ZI).

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

  The content of the combined acid generator in the composition is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, further preferably 3 to 8% by mass, based on the total solid content of the resist composition. Most preferably, it is 4-7 mass%.

[2] Resin whose dissolution rate in an alkaline developer is increased by the action of an acid The resin whose dissolution rate in an alkaline developer is increased by the action of an acid used in the positive photosensitive composition of the present invention is as follows. A resin having an acid-decomposable repeating unit represented by formula (I) (also referred to as “resin of component (B)”).

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry _{1 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. Ry _{1 to} Ry ₃
At least two of these may be bonded to form a monocyclic or polycyclic hydrocarbon structure.
Z represents a divalent linking group.

In general formula (I), the alkyl group of Xa ₁ may be substituted with a hydroxyl group, a halogen atom, or the like.
Xa ₁ is preferably a hydrogen atom or a methyl group.
The alkyl group of Ry _{1 to} Ry ₃ may be either a linear alkyl group or a branched alkyl group, and may have a substituent. Preferred linear and branched alkyl groups have 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms, and include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and t-butyl groups. And preferably a methyl group or an ethyl group.
The cycloalkyl group of Ry ₁ to Ry _3, for example, a monocyclic cycloalkyl group having 3 to 8 carbon atoms may be a cycloalkyl group polycyclic 7-14 carbon atoms, optionally substituted Also good. Preferred examples of the monocyclic cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cyclopropyl group. Preferred examples of the polycyclic cycloalkyl group include an adamantyl group, a norbornane group, a tetracyclododecanyl group, a tricyclodecanyl group, and a diamantyl group.

As the monocyclic hydrocarbon structure formed by combining at least two members out of Ry _{1 to} Ry ₃ , a cyclopentyl group and a cyclohexyl group are preferable. As the polycyclic hydrocarbon structure formed by bonding at least two of Ry _{1 to} Ry ₃ , an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are preferable.
Z is preferably a divalent linking group having 1 to 20 carbon atoms, more preferably a chain alkylene group having 1 to 4 carbon atoms, a cyclic alkylene group having 5 to 20 carbon atoms, or a combination thereof.
Examples of the chain alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, a propylene group, and a butylene group, which may be linear or branched. A methylene group is preferred.
Examples of the cyclic alkylene group having 5 to 20 carbon atoms include monocyclic cyclic alkylene groups such as cyclopentylene group and cyclohexylene group, and polycyclic cyclic alkylene groups such as norbornylene group and adamantylene group. An adamantylene group is preferred.

  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.

  Preferred specific examples of the repeating unit represented by formula (I) are shown below, but the present invention is not limited thereto.

  The repeating unit 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 alkaline developer increases.

In addition to the acid-decomposable repeating unit represented by formula (I), the resin of component (B) may further have another acid-decomposable repeating unit.
Other acid-decomposable repeating units other than the acid-decomposable repeating unit represented by the general formula (I) are preferably repeating units 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. At least two of Rx _{1 to} Rx ₃ may be bonded to form a cycloalkyl group.

The alkyl group of Rx _{1 to} Rx ₃ is linear or branched having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group. The shape is preferred.
Examples of the cycloalkyl group represented by Rx _{1 to} Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl group and cyclohexyl group, polycyclic cycloalkyl groups such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group, and adamantyl group. Groups are 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 each other to bond the above monocyclic or polycyclic cycloalkyl group.

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

  When the repeating unit having an acid-decomposable group represented by the general formula (I) and a repeating unit having another acid-decomposable group (preferably a repeating unit represented by the general formula (II)) are used in combination, The ratio of the repeating unit having an acid-decomposable group represented by the general formula (I) and the repeating unit having another acid-decomposable group is 90:10 to 10:90, more preferably 80 in terms of molar ratio. : 20 to 20:80.

  The content of repeating units having all acid-decomposable groups in the resin of component (B) is preferably 20 to 50 mol%, more preferably 25 to 45 mol%, based on all repeating units in the polymer.

  The resin as the component (B) preferably further has a repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group.

The resin of component (B) preferably has a repeating unit having a lactone structure.
Any lactone structure can be used as long as it has a lactone structure, but a 5- to 7-membered lactone structure is preferable, and a bicyclo structure or a spiro structure is formed in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). The 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 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. 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.

  Examples of the repeating unit having a lactone structure represented by any one 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 having 1 to 4 carbon atoms. Preferable substituents that the alkyl group for R _b0 may have include a hydroxyl group and a halogen atom. Examples of the halogen atom for R _b0 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R _b0 is preferably a hydrogen atom or a methyl group.
A _b is a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent linking that is a combination thereof. Represents a group. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent 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 having a structure 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 having a lactone structure 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 having a lactone structure are given below, but the present invention is not limited thereto.

  Particularly preferred repeating units having a lactone structure include the following repeating units. By selecting the optimum lactone structure, the pattern profile and the density dependence become good.

The resin as the component (B) preferably has 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 5 to 40 mol%, more preferably 5 to 30 mol%, still more preferably 10 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.

  As the repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group, more preferably, a repeating unit having at least two groups selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group Preferably, it is a repeating unit having a cyano group and a lactone group. Particularly preferred is a repeating unit having a structure in which a cyano group is substituted on the lactone structure of LCI-4.

  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. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, the (meth) acrylate repeating unit having an acid-decomposable group represented by the general formula (I) is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone structure is 20 to 50 mol%, It is a copolymer having 5 to 30 mol% of (meth) acrylate-based repeating units having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and further containing 0 to 20 mol% of other (meth) acrylate-based repeating units. .

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.

  When the resin of component (B) is used for a positive photosensitive composition that irradiates KrF excimer laser light, electron beam, X-ray, high energy light (EUV, etc.) having a wavelength of 50 nm or less, The resin preferably has a repeating unit of the general formula (I) and further a repeating unit having a hydroxystyrene structure. Examples of the repeating unit having a hydroxystyrene structure include o-, m-, p-hydroxystyrene and / or hydroxystyrene protected with an acid-decomposable group. The hydroxystyrene repeating unit protected with an acid-decomposable group is preferably 1-alkoxyethoxystyrene or t-butylcarbonyloxystyrene. In addition to the repeating unit represented by the general formula (I) and the repeating unit having a hydroxystyrene structure, it may further have a repeating unit represented by the general formula (II).

Specific examples of the resin having a repeating unit having a hydroxystyrene structure and a repeating unit represented by formula (I) used in the present invention are shown below, but the present invention is not limited thereto. In specific examples, Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.

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 99.99% 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 preferred compounds include compounds having an imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate structure, trialkylamine structure, aniline structure or pyridine structure, alkylamine derivatives having a hydroxyl group and / or an ether bond, hydroxyl groups 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). %.

Surface Hydrophobic Resin When the resist film made of the positive photosensitive composition of the present invention is exposed through immersion water, a surface hydrophobizing resin can be further added as necessary. Thereby, the receding contact angle on the resist film surface can be improved and the immersion water followability can be improved. As the surface hydrophobizing resin, any resin can be used as long as the receding contact angle of the surface can be improved by addition, but a resin having at least one of fluorine atom and silicon atom is preferable. The addition amount can be adjusted as appropriate so that the receding contact angle of the resist film is 60 ° to 80 °, but preferably 0.1 to 5% by mass.

<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. The mixed solvent containing two or more kinds of solvents having different functional groups is at least selected from a solvent having a hydroxyl group, a solvent having an ester structure, a solvent having a ketone structure, a solvent having a lactone structure, and a solvent having a carbonate structure. A mixed solvent containing two kinds is preferred. As the mixed solvent having different functional groups, the following mixed solvents (S1) to (S6) 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 solvent having an ester structure, a solvent having a carbonate structure, and a mixed solvent containing a hydroxyl group,
(S6) A mixed solvent containing at least a solvent having an ester structure, a solvent having a ketone structure, and a solvent having a lactone structure.
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 2-heptanone 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 in (S1) 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 in (S2) is 1/99 to 99/1, preferably 10/90 to 90/10, 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 in (S3) is 70/30 to 99/1, preferably 80/20 to 99/1, 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.
In mixing the solvent having an ester structure, the solvent having a lactone structure, and the solvent containing a hydroxyl group in (S4), the solvent having an ester structure is 30 to 80% by weight, and the solvent having a lactone structure is 1 to 20% by weight. It is preferable to contain 10 to 60% by weight of a solvent containing a hydroxyl group.
When mixing the solvent having an ester structure, the solvent having a carbonate structure, and the solvent containing a hydroxyl group in (S5), the solvent having an ester structure is 30 to 80% by weight, and the solvent having a carbonate structure is 1 to 20% by weight. It is preferable to contain 10 to 60% by weight of a solvent containing a hydroxyl group.
In mixing the solvent having an ester structure, the solvent having a ketone structure, and the solvent having a lactone structure in (S6), 30 to 80% by weight of the solvent having an ester structure and 10 to 60% by weight of the solvent having a ketone structure %, And preferably 1 to 20% by weight of a solvent containing a lactone structure.

<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. The amount is preferably 50% by mass or less from the viewpoint of suppressing development residue and preventing pattern deformation during 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 the above components in a predetermined organic solvent, preferably the mixed solvent, filtering the solution, and 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 formed on a substrate (for example, silicon / silicon dioxide coating) used for manufacturing a precision integrated circuit element by an appropriate coating method such as a spinner or a coater to have an arbitrary thickness (usually 50 to 500 nm). After application, the resist film is formed by drying by spinning or baking. The bake temperature can be set as appropriate, but is usually 60 to 150 ° C, and preferably 90 to 130 ° C.

Next, exposure is performed through a mask or the like for pattern formation.
Although an exposure amount can be set suitably, it is 1-100 mJ / cm < ² > normally. After exposure, preferably, spinning or / and baking is performed, development and rinsing are performed to obtain a pattern.

  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, the elution of the composition from the photosensitive 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.

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

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

The positive resist composition of the present invention may be applied to a multilayer resist process (particularly a three-layer resist process). The multilayer resist method includes the following processes.
(a) A lower resist layer made of an organic material is formed on a substrate to be processed.
(b) On the lower resist layer, an intermediate layer and an upper resist layer made of an organic material that crosslinks or decomposes upon irradiation are sequentially laminated.
(c) After forming a predetermined pattern in the upper resist layer, the intermediate layer, the lower layer and the substrate are sequentially etched.
As the intermediate layer, organopolysiloxane (silicone resin) or SiO ₂ coating solution (SOG) is generally used. As the lower layer resist, an appropriate organic polymer film is used, but various known photoresists may be used. For example, each series of the Fuji Film Arch FH series, FHi series, or Sumitomo Chemical PFI series can be illustrated.
The film thickness of the lower resist layer is preferably 0.1 to 4.0 μm, more preferably 0.2 to 2.0 μm, and particularly preferably 0.25 to 1.5 μm. A thickness of 0.1 μm or more is preferable from the viewpoint of antireflection and dry etching resistance, and a thickness of 4.0 μm or less is preferable from the viewpoint of aspect ratio and pattern collapse of the formed fine pattern.

  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, 8.8 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. To this, 8.5 g of γ-butyrolactone methacrylate, 4.7 g of 3-hydroxyadamantyl-1-methacrylate, 8.8 g of 2-methyl-2-adamantyloxycarbonylmethyl methacrylate, polymerization initiator V-60 (manufactured by Wako Pure Chemical Industries) 13mo for monomer
A solution prepared by dissolving 1% in 79 g of cyclohexanone was added dropwise 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 added dropwise to a mixed solution of 900 m of methanol / 100 ml of water over 20 minutes, and the precipitated powder was collected by filtration and dried to obtain 18 g of Resin (RA-1). The weight average molecular weight of the obtained resin was 6200 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.63.

  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 structures of the resins (RA-1) to (RA-12) and the resin (RX) used in Examples and Comparative Examples are shown.

[Examples 1-12 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 8% by mass, and this was filtered through a 0.03 micron 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 Table 1.

<Resist evaluation>
An anti-reflective coating DUV-42 manufactured by Brewer Science Co., Ltd. was uniformly applied to 600 angstroms on a silicon substrate subjected to hexamethyldisilazane treatment with a spin coater, dried on a hot plate at 100 ° C. for 90 seconds, and then at 190 ° C. Heat drying was performed 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.
An ArF excimer laser stepper (ASML) is passed through the mask to this resist film.
(NA = 0.75 manufactured by company, 2/3 ring zone), and immediately after the exposure, it was heated 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 line pattern.

Pattern collapse evaluation method:
When the exposure amount that reproduces the 85nm line and space mask pattern is set as the optimal exposure amount and the line width of the line pattern formed by further increasing the exposure amount from the optimal exposure amount is reduced, the pattern does not collapse. It was defined by the line width to be resolved. The smaller the value, the finer pattern is resolved without falling, and the pattern collapse 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 85 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 85 nm was observed. A rectangular pattern was indicated by ◯, a slightly tapered pattern was indicated by △, and a film loss was indicated by x.

  Hereinafter, abbreviations in the table are shown.

  [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

[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: Troisol 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

(Immersion exposure)
<Resist preparation>
The components of Examples 1 to 12 and Comparative Examples 1 to 3 in Table 1 were dissolved in a solvent to prepare a solution having a solid content concentration of 5% by mass, and this was filtered through a 0.03 μm polyethylene filter to obtain a positive resist solution. It was adjusted. 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. The resist composition 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), a laser, a diaphragm, a shutter, three reflecting mirrors, and a condenser lens were used, and the wafer was exposed through a prism and an immersion liquid. The laser wavelength was 193 nm, and a prism that formed 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 12 were used, a 65 nm line and space pattern was resolved without causing pattern collapse. When the compositions of Comparative Examples 1 to 3 were used, a 65 nm line and space pattern was resolved, but pattern collapse was observed in some patterns.

  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.

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 (6)

(A) a compound that generates an acid represented by the following general formula (II) by irradiation with actinic rays or radiation, and
(B) A positive photosensitive composition comprising a resin having an acid-decomposable repeating unit represented by the following general formula (I) 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 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a ring structure.
Z represents a divalent linking group.
In general formula (II):
Rb1 represents an electron-withdrawing group.
Rb2 represents an organic group other than the electron-withdrawing group.
m = 0 to 5, n = 0 to 5, and m + n ≦ 5.
When m is 2 or more, a plurality of Rb1 may be the same or different.
When n is 2 or more, a plurality of Rb2s may be the same or different.   (A) In the general formula (II), m is 1 to 5, and the electron withdrawing group of Rb1 is at least one selected from a fluorine atom, a fluoroalkyl group, a nitro group, an ester group, and a cyano group. The positive photosensitive composition according to claim 1, wherein   The positive photosensitive composition according to claim 1 or 2, wherein the resin as the component (B) further has a repeating unit having at least one kind selected from a lactone group, a hydroxyl group, a cyano group, and an acid group. object.   In the general formula (I), Z is a divalent chain hydrocarbon group or a divalent cyclic hydrocarbon group. Composition.   The general formula (II), wherein m = 1 to 5, n = 0 to 5, m + n ≦ 5, and Rb1 or Rb2 is a group containing an alkyl structure having 4 to 20 carbon atoms. The positive photosensitive composition described in 1.   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.