JP2010191416A - Chemically amplified photoresist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemically amplified photoresist composition for immersion exposure, or the like which is less in the production of foreign substance when being used for an immersion exposure. <P>SOLUTION: The chemically amplified photoresist composition for immersion exposure contains an acid generator, a resin, a basic compound, a solvent and a surfactant, wherein the rate of the fluorine content in the solid content of the composition is ≤0.5 mass%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a chemically amplified photoresist composition for immersion exposure used for microfabrication of a semiconductor, and a pattern forming method using the chemically amplified photoresist composition for immersion exposure. More specifically, the present invention relates to a chemically amplified positive photoresist composition for immersion exposure.

  In microfabrication of semiconductors, it is desirable to form an excellent pattern. For example, a chemically amplified resist composition for immersion exposure is one that generates less foreign matter when it comes into contact with the liquid used for immersion exposure. Is required.

Optical / Electronic Functional Organic Materials Handbook, 444-458 pages (published by Asakura Shoten, October 15, 1997, first edition, second edition)

  An object of the present invention is to provide a chemically amplified photoresist composition or the like for immersion exposure that generates less foreign matter when used in immersion exposure.

Then, as a result of examining the above problems, the present inventors have reached the present invention. That is, the present invention provides the following.
1. A chemically amplified photoresist composition for immersion exposure containing an acid generator, a resin, a basic compound, a solvent, and a surfactant, and the fluorine content in the solid content of the composition is 0.5% by mass or less. The composition characterized by these.
2. 2. The composition according to item 1, wherein a fluorine content in the acid generator is 10% by mass or less.
3. 3. The composition according to 1 or 2 above, wherein the acid generator is a compound represented by the formula (a).

[In the formula (a), Z ⁺ represents an organic cation.
A represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 36 carbon atoms. The hydrogen atom contained in the aromatic hydrocarbon group and the linear, branched or cyclic hydrocarbon group is a halogen atom, a hydroxyl group, a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms. A linear or branched alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, a glycidoxy group, or an acyl group having 2 to 4 carbon atoms. The methylene group contained in the alicyclic hydrocarbon group, the aliphatic hydrocarbon group, the alkoxy group and the aralkyl group may be substituted with an oxygen atom and / or a carbonyl group. . ]

4). 4. The composition according to 3 above, wherein A is a group represented by formula (a1) or a group represented by formula (a2).

Wherein (a1) and the formula (a2), ^{X 1} is a single bond or - _{[CH 2] k} - represents, the - _{[CH 2] k} - methylene group contained in the oxygen atom and / or a carbonyl group in may be substituted, the _- [CH _2] k - a hydrogen atom may be substituted with a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms included. k represents an integer of 1 to 17.
Y ¹ is an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or a linear, branched or cyclic aliphatic carbon group having 1 to 36 carbon atoms which may have a substituent. Represents a hydrogen group, and the methylene group contained in the aliphatic hydrocarbon group may be substituted with an oxygen atom and / or a carbonyl group. However, if Y ¹ is a linear or branched aliphatic hydrocarbon group of the, X ¹ is intended to represent a single bond.
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]

5). Said (a1) is a C1-C10 perfluoro group, a C1-C4 aliphatic hydrocarbon group which may be substituted with a C1-C4 aromatic hydrocarbon group, C1-C4 5. The composition according to 4 above, which is an alicyclic hydrocarbon group having 6 to 20 carbon atoms which may be substituted with an aliphatic hydrocarbon group.
6). 6. The composition according to any one of 3 to 5, wherein Z ⁺ is a cation represented by the formula (IXa).

[In formula (IXa), P ¹ , P ² and P ³ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched group. Represents an alkoxy group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group includes a halogen atom, a hydroxyl group, and 1 to 1 carbon atoms. It is substituted with 12 alkyl groups, C1-C12 alkoxy groups, C6-C12 aromatic hydrocarbon groups, C7-C12 aralkyl groups, glycidoxy groups, or C2-C4 acyl groups. May be. ]
7). 7. The composition according to any one of the preceding items 1 to 6, wherein the resin is a resin (B) having a structural unit having an alkali-soluble group, a structural unit having a hydroxyl group, and a structural unit having an acid leaving group. object.
8). 8. The composition according to any one of the preceding items 1 to 7, wherein the resin further comprises a resin that is not the same as the resin (B) and has a group that becomes alkali-soluble by the action of an acid.
9. A pattern forming method including the following steps.
(1) A step of applying the composition according to any one of items 1 to 8 on a substrate (2) A step of removing a solvent from the composition after application to form a composition layer (3) A composition layer Step of exposing using immersion exposure machine (4) Step of heating composition layer after exposure (5) Step of developing composition layer after heating using developing device

  According to the present invention, it is possible to provide a chemically amplified photoresist composition or the like that can form a pattern with less foreign matter generated when the resist film comes into contact with water.

The chemically amplified photoresist composition of the present invention (hereinafter sometimes referred to as “resist composition”) is a chemical amplification for immersion exposure containing an acid generator, a resin, a basic compound, a solvent and a surfactant. Type photoresist composition, wherein the fluorine content in the solid content of the composition is 0.5% by mass or less.
The fluorine content in the solid content of the composition is preferably 0.1% by mass or more and 0.5% by mass or less. Within this range, the shape of the resulting pattern will be good.
The fluorine content in the acid generator is preferably 10% by mass or less, more preferably 1% by mass or more and 8% by mass or less, and further preferably 2% by mass or more and 7.5% by mass or less.

The fluorine content in the solid content of the composition can be calculated by the following formula.
100 × (fluorine content in the solid content of the composition)
Fluorine content = ―――――――――――――――――――――――――――
(Solid content of composition)
The solid content of the composition can be determined by summing the amounts of components other than the solvent contained in the composition.
The fluorine content in the solid content of the composition can be determined by calculating the fluorine content of each component other than the solvent. For those for which the fluorine content cannot be determined, the concentration can be determined by a fluorine densitometer to determine the fluorine content.
The fluorine content in the acid generator can be calculated by the following formula.
Fluorine content in acid generator 100 × (number of fluorine atoms per molecule of acid generator) × (atomic weight of fluorine atoms)
= ――――――――――――――――――――――――――――――――――――
(Molecular weight of acid generator)

  Examples of the acid generator include compounds represented by the formula (a).

[In the formula (a), Z ⁺ represents an organic cation.
A represents a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 36 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms.
The hydrogen atom contained in the cyclic aliphatic hydrocarbon group and the aromatic hydrocarbon group is a halogen atom, a hydroxyl group, a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, a linear or The aliphatic hydrocarbon group and the alkoxy group may be substituted with a branched alkoxy group having 1 to 12 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, a glycidoxy group, or an acyl group having 2 to 4 carbon atoms. And the methylene group contained in the aralkyl group may be substituted with an oxygen atom and / or a carbonyl group. ]

Examples of the linear, branched or cyclic aliphatic hydrocarbon group having 1 to 36 carbon atoms in A include, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n- Hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group,
Isopropyl group, sec-butyl group, tert-butyl group, 2-ethylhexyl group, tert-octyl group,
Examples include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, cycloundecyl group, cyclododecyl group, norbornyl group, adamantyl group, isobornyl group and the like.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, Preferably a fluorine atom is mentioned.
As the linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, for example, among the above-mentioned linear branched or cyclic aliphatic hydrocarbon groups having 1 to 36 carbon atoms, Or the branched thing of C1-C12 is mentioned.
Examples of the linear or branched alkoxy group having 1 to 12 carbon atoms include methoxy group, ethoxy group, n-propoxy group, n-butoxy group, n-pentyloxy group, n-hexyloxy group, n- Heptyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group,
An isopropoxy group, a sec-butoxy group, a tert-butoxy group, a 2-ethylhexyloxy group, a tert-octyloxy group and the like can be mentioned.
As an aralkyl group having 7 to 21 carbon atoms,
Examples of the acyl group having 2 to 4 carbon atoms include a methylcarbonyl group, an ethylcarbonyl group, an n-propylcarbonyl group, and an isopropylcarbonyl group.
In each of the above groups, the methylene group may be substituted with an oxygen atom and / or a carbonyl group.
Especially, as A in a formula (a), Preferably, the group represented by (a1) or the group represented by a formula (a2) is mentioned.

Wherein (a1) and the formula (a2), ^{X 1} is a single bond or - _{[CH 2] k} - represents, the - _{[CH 2] k} - methylene group contained in the oxygen atom and / or a carbonyl group in may be substituted, the _- [CH _2] k - a hydrogen atom may be substituted with a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms included. k represents an integer of 1 to 17.
Y ¹ is an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or a linear, branched or cyclic aliphatic carbon group having 1 to 36 carbon atoms which may have a substituent. Represents a hydrogen group, and the methylene group contained in the aliphatic hydrocarbon group may be substituted with an oxygen atom and / or a carbonyl group. However, if Y ¹ is a linear or branched aliphatic hydrocarbon group of the, X ¹ is intended to represent a single bond.
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]

Examples of — [CH ₂ ] _k — include a methylene group, a dimethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, and an undecamethylene group. Group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptacamethylene group, ethylene group, propylene group, and propylidene group.
Examples of the group in which the methylene group contained in — [CH ₂ ] _k — is substituted with an oxygen atom and / or a carbonyl group include —X ¹¹ —O—, —X ¹¹ —CO—O—, and —X ¹¹ —. O—CO—, —X ¹¹ —O—X ¹² — and the like are mentioned, preferably —X ¹¹ —O— and —X ¹¹ —CO—O— are mentioned, and more preferably —X ¹¹ —CO—O. -.
Here, X ¹¹ and X ¹² each independently represent a linear or branched alkylene group having 1 to 15 carbon atoms. However, in the group in which the methylene group contained in the alkylene group is substituted, the number of atoms constituting the main chain of each of the above groups is 1 to 17, which is the same as k.
Examples of the linear or branched alkylene group having 1 to 17 carbon atoms include methylene group, dimethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, and nonamethylene. Group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, ethylene group, isopropylene group, sec-butylene group , Tert-butylene group and the like.
Examples of the linear or branched aliphatic hydrocarbon group having 1 to 36 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. Group, n-pentyl group, n-hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group and the like.

Examples of the anion of the compound represented by the formula (a), for example, the as anion and X ¹ of formula (IA) with a single bond or a linear alkylene group having 1 to 6 carbon atoms as X ¹ - X ¹¹ anion represented by the formula (IB) having a -CO-O-, ^-X 11 as an anion and ^{X 1} of the formula (IC) having an ^-X 11 -O-CO- as ^{X 1} -O An anion having —X ¹¹ — includes, for example, formula (ID), and preferably an anion represented by formula (IA) and formula (IB) is used.

[In formula (IA), formula (IB), formula (IC) and formula (ID), Q ¹ , Q ² and Y ¹ represent the same as those in formula (a).
X ¹⁰ represents a single bond or a linear or branched alkylene group having 1 to 15 carbon atoms. X ¹¹ and X ¹² each independently represent a linear or branched alkylene group having 1 to 15 carbon atoms. ]

Y ¹ represents an alicyclic hydrocarbon group having 4 to 36 carbon atoms which may have a substituent, preferably a group represented by the formula (III).

[In Formula (III), Ring W represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group is substituted with an oxygen atom or a carbonyl group. Also good.
R ^b is independently of each other a halogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 21 carbon atoms. Represents a glycidoxy group or an acyl group having 2 to 4 carbon atoms.
x represents an integer of 0 to 8. When x is 2 or more, the plurality of R ^b may be the same or different.
R ^a represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 6 carbon atoms. ]

x represents an integer of 0 to 8, preferably an integer of 0 to 6, more preferably an integer of 0 to 4.

Examples of the alicyclic hydrocarbon group having 3 to 36 carbon atoms include cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, 1-adamantyl group, 2- An adamantyl group, an isobornyl group, etc. are mentioned.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, Preferably a fluorine atom and a chlorine atom are mentioned.
Examples of the linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, Examples include n-pentyl group, n-hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group and the like.

  The ring W includes the formula (W1), the formula (W2), the formula (W3), the formula (W4), the formula (W5), the formula (W6), the formula (W7), the formula (W8), and the formula (W9). ), Formula (W10), Formula (W11), Formula (W12), Formula (W13), Formula (W14), Formula (W15), Formula (W16), Formula (W17), Formula (W18), and Formula (W19) ), And the like, preferably, groups represented by formula (W12), formula (W15), formula (W16), and formula (W19).

Y ¹ is a group in which a hydrogen atom contained in the ring W is not substituted or substituted only with a hydrocarbon group (provided that the methylene group contained in the ring W is substituted with an oxygen atom) And a group substituted with a hydroxyl group or a group containing a hydroxyl group (excluding those having a lactone structure) and two adjacent methylene groups contained in the ring W are substituted with an oxygen atom and a carbonyl group. Examples include a group having a lactone structure, a group having a ketone structure in which one methylene group contained in ring W is substituted with a carbonyl group, and a group in which a hydrogen atom contained in ring W is substituted with an aromatic hydrocarbon group. .

Hydrogen atoms contained in the ring W is substituted only with one or a hydrocarbon group not substituted (methylene group contained in the hydrocarbon group is an oxygen atom may be substituted.) As Y ¹ is For example, the following groups are mentioned.

Examples of Y ¹ in which a hydrogen atom contained in ring W is substituted with a hydroxyl group or a group containing a hydroxyl group (however, having no lactone structure) include the following groups.

Examples of Y ¹ having a lactone structure in which two adjacent methylene groups contained in ring W are substituted with a carbonyl group and an oxygen atom include the following groups.

Examples of Y ¹ having a ketone structure in which one methylene group contained in ring W is substituted with a carbonyl group include the following groups.

Examples of Y ¹ in which a hydrogen atom contained in the ring W is substituted with an aromatic hydrocarbon group include the following groups.

Examples of Y ¹ having an ether structure in which one methylene group contained in the ring W is substituted with an oxygen atom include the following groups.

  Examples of the anion represented by the formula (IA) include the following.

  In formula (IA), a group in which a hydrogen atom contained in ring W is substituted only with a hydrocarbon group (a methylene group contained in the hydrocarbon group may be substituted with an oxygen atom). Examples include the following.

  In the formula (IA), specific examples of the anion in which the hydrogen atom contained in the ring W is substituted with a hydroxyl group or a group containing a hydroxyl group (but not having a lactone structure) include the following. It is done.

  In the formula (IA), specific examples of the anion having a lactone structure in which two adjacent methylene groups contained in the ring W are substituted with an oxygen atom and a carbonyl group include the following.

  In the formula (IA), specific examples of the anion having a ketone structure in which the methylene group contained in the ring W is substituted with a carbonyl group include the following.

  In the formula (IA), specific examples of the anion in which the hydrogen atom contained in the ring W is substituted with an aromatic hydrocarbon group include the following.

  In the formula (IA), specific examples of the anion having an ether structure in which the methylene group contained in the ring W is substituted with an oxygen atom include the followings.

  Examples of the anion represented by the formula (IB) include the following.

[In formula (IB), Q ¹ , Q ² and Y ¹ represent the same as those in formula (a). X ¹¹ represents an optionally substituted linear or branched aliphatic hydrocarbon group having 1 to 15 carbon atoms. ]

  In formula (IB), the hydrogen atom contained in ring W is not substituted or substituted only with a hydrocarbon group (the methylene group contained in ring W may be substituted with an oxygen atom). Specific examples include the following.

  In the formula (IB), specific examples of the anion in which the hydrogen atom contained in the ring W is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

  In the formula (IB), specific examples of the anion having a lactone structure in which two adjacent methylene groups contained in the ring W are substituted with an oxygen atom and a carbonyl group include the following.

  In the formula (IB), specific examples of the anion having a ketone structure in which one methylene group contained in the ring W is substituted with a carbonyl group include the following.

  Specific examples of the anion in which the hydrogen atom contained in the ring W in the formula (IB) is substituted with an aromatic hydrocarbon group include the following.

  Specific examples of the anion represented by the formula (IC) include the following.

  In formula (IC), a hydrogen atom contained in ring W is not substituted or substituted only with a hydrocarbon group (a methylene group contained in ring W may be substituted with an oxygen atom). Specific examples include the following.

  In the formula (IC), specific examples of the anion in which the hydrogen atom contained in the ring W is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

  Specific examples of the anion having a ketone structure in which one methylene group contained in the ring W is substituted with a carbonyl group in the formula (IC) include the following.

  Specific examples of the anion represented by the formula (ID) include the following.

  In formula (ID), the hydrogen atom contained in ring W is not substituted or substituted only with a hydrocarbon group (the methylene group contained in ring W may be substituted with an oxygen atom). Specific examples include the following.

  In the formula (ID), specific examples of the anion in which the hydrogen atom contained in the ring W is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

  In the formula (ID), specific examples of the anion having a ketone structure in which one methylene group contained in the ring W is substituted with a carbonyl group include the following.

Examples of Z ⁺ in formula (a) include cations such as formula (IXz), formula (IXb), formula (IXc), and formula (IXd).

[In the formula (IXz), P ^a , P ^b and P ^c each independently represent a linear or branched alkyl group having 1 to 30 carbon atoms or an alicyclic hydrocarbon group having 3 to 30 carbon atoms. To express. When any one of P ^a , P ^b and P ^c is an alkyl group, the alkyl group is a hydroxyl group, a linear or branched alkoxy group having 1 to 12 carbon atoms, or a cyclic carbonization having 3 to 12 carbon atoms. It may be substituted with a hydrogen group, and when any of P ^a , P ^b and P ^c is an alicyclic hydrocarbon group, a hydroxyl group, a linear or branched alkyl having 1 to 12 carbon atoms Group or an alkoxy group having 1 to 12 carbon atoms.
In formula (IXb), P ⁴ and P ⁵ each independently represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
In formula (IXc), P ⁶ and P ⁷ each independently represent a linear or branched alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms, or P ⁶ and P ^7. And may form a ring having 3 to 12 carbon atoms.
P ⁸ represents a hydrogen atom, and P ⁹ is a linear or branched alkyl group having 1 to 12 carbon atoms and a C 6 to 20 carbon atom that may be substituted with a cycloalkyl group having 3 to 12 carbon atoms. Or a ring having 3 to 12 carbon atoms may be formed by combining P ⁸ and P ⁹ together.
In formula (IXd), P ^{10 to} P ²¹ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. E represents a sulfur atom or an oxygen atom.
m represents 0 or 1. ]

Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl. Groups and the like.
Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclodecyl group.
As a C6-C20 aromatic hydrocarbon group which may be substituted, a phenyl group, a naphthyl group, a benzyl group, a toluyl group etc. are mentioned, for example.
Among the cations represented by the formula (IXz), for example, a cation represented by the formula (IXa) and the like are preferable.

[In Formula (IXa), P ^{1 to} P ³ are each independently a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched carbon number 1 to 1. Represents an alkoxy group having 12 carbon atoms or an alicyclic hydrocarbon having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, a hydroxyl group, a linear or branched carbon atom having 1 to 12 carbon atoms. An alkyl group, a linear or branched alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidoxy group, or an acyl group having 2 to 4 carbon atoms. May be substituted. ]

Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group etc. are mentioned.
Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group and the like.
Examples of the cyclic hydrocarbon group include those containing an adamantyl skeleton and an isobornyl skeleton, preferably a 2-alkyl-2-adamantyl group, a 1- (1-adamantyl) -1-alkyl group and an isobornyl group. It is done.

  Specific examples of the cation represented by the formula (IXa) include the followings.

  Among the cations represented by the formula (IXa), the cation represented by the formula (IXe) is preferably used because of its easy production.

[In formula (IXe), P ²² , P ²³ and P ²⁴ are independently of each other a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched carbon atom. The number 1-12 alkoxy group is represented. ]

  Specific examples of the cation represented by the formula (IXb) include the followings.

  Specific examples of the cation represented by the formula (IXc) include the followings.

  Specific examples of the cation represented by the formula (IXd) include the followings.

  The above anions and cations can be arbitrarily combined.

  The compounds represented by formula (a) may be used alone or in combination of two or more. The compound represented by formula (a) is represented by formula (Xa), formula (Xb), formula (Xc), formula (Xd), formula (Xe), formula (Xf), formula (Xg) or formula (Xh). It is preferable because it becomes a compound that generates an acid that gives a resist composition exhibiting excellent resolution performance and pattern shape.

[In Formulas (Xa) to (Xi), P ²⁵ , P ²⁶ and P ²⁷ are each independently a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms, or 4 carbon atoms. -36 alicyclic hydrocarbon groups are represented.
P ²⁸ and P ²⁹ each independently represent a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 4 to 36 carbon atoms, or P ²⁸ and may form a ring of 2 to 6 carbon atoms include S ⁺ and P ²⁹ together.
P ³⁰ is a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 4 to 36 carbon atoms, or an optionally substituted aromatic group having 6 to 20 carbon atoms. It represents a hydrocarbon group, or P ³⁰ and P ³¹ may form a ring having 3 to 12 carbon atoms together. Here, the methylene group contained in the ring may be optionally substituted with an oxygen atom, a sulfur atom or a carbonyl group.
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹³ represents a single bond or a methylene group. ]

  Of the above combinations, specifically, the following acid generators are preferable.

Among them, in the cation represented by the formula (IXe) as a cation, specific examples of the triphenylsulfonium cation in which P ²² , P ²³ and P ²⁴ are all hydrogen atoms and the anion represented by the formula (IB) Acid generators in combination with those listed are preferred.

The resist composition of the present invention contains a resin, and the resin used for the chemically amplified resist composition for immersion exposure can be used as the resin.
Examples of the resin include a resin that is insoluble or hardly soluble in the developer, but becomes soluble in the developer by acting on an acid. Insoluble or those having a structural unit represented by the formula (II) by the action of an acid.

[In Formula (II), R ¹ represents a hydrogen atom or a methyl group.
X ² represents a single bond or — [CH ₂ ] _k —, and the methylene group contained in — [CH ₂ ] _k — may be substituted with an oxygen atom and / or a carbonyl group.
k represents an integer of 1 to 8.
Y ² represents a hydrocarbon group having 4 to 36 carbon atoms having an alicyclic hydrocarbon group, a hydrogen atom contained in the alicyclic hydrocarbon group, a halogen atom, a hydroxyl group, a linear or branched An aliphatic hydrocarbon group having 1 to 12 carbon atoms, a linear or branched alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, and glycidoxy Group or an acyl group having 2 to 4 carbon atoms may be substituted, and the methylene group contained in the hydrocarbon group may be substituted with an oxygen atom and / or a carbonyl group. ]

  Specific examples of the structural unit represented by the formula (II) include fats such as isobornyl ester, 2-alkyl-2-adamantyl ester, and 1- (1-adamantyl) -1-alkyl ester. Examples include structural units derived from cyclic esters and the like.

  Among these, the structural unit represented by the formula (IIa) or the formula (IIb) is preferable.

[In Formula (IIa) and Formula (IIb), R ¹ represents a hydrogen atom or a methyl group.
R ² represents a linear or branched aliphatic hydrocarbon group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms.
R ³ represents a methyl group.
n represents an integer of 0 to 14.
R ⁴ and R ⁵ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms which may contain a hetero atom, or R ⁴ and R ⁵ together represent 3 to 12 carbon atoms. The ring may contain a hetero atom. A double bond may be formed between the carbon atom to which R ⁴ is bonded and the carbon atom to which R ⁵ is bonded.
m represents an integer of 1 to 3.
Z ″ represents a single bond, — [CH ₂ ] _k —, and the methylene group contained in — [CH ₂ ] _k — may be substituted with an oxygen atom and / or a carbonyl group.
k represents an integer of 1 to 8. ]

  Specific examples of the monomer for deriving the structural unit represented by the formula (IIa) include the following.

  Specific examples of the monomer for deriving the structural unit represented by the formula (IIb) include the following.

  Among these, for example, (meth) acrylic acid 2-ethyl-2-adamantyl, (meth) acrylic acid 2-isopropyl-2-adamantyl, or methacrylic acid 1- (2-methyl-2-adamantyloxycarbonyl) methyl, etc. Preferable examples can be given.

  (II) may include a plurality of structural units having a hydroxyl group (excluding the —OH group of the carboxyl group) in the side chain.

  Examples of the structural unit having a hydroxyl group (excluding the —OH group of the carboxyl group) in the side chain include, for example, various esters of carboxylic acid, specifically, cyclic alkyl esters represented by, for example, cyclopentyl ester and cyclohexyl ester. A structural unit in which a part of a polycyclic ester such as norbornyl ester, 1-adamantyl ester, or 2-adamantyl ester is substituted with a hydroxyl group.

  Among these, the structural unit represented by the formula (III) can be exemplified.

[In the formula (III), R ³¹ represents a hydrogen atom or a methyl group.
R ⁶ and R ⁷ each independently represent a hydrogen atom, a methyl group or a hydroxyl group.
R ⁸ represents a methyl group.
n ′ represents an integer of 0 to 10.
Z ″ represents the same meaning as in formula (IIa). ]

  Specific examples of the monomer for deriving the structural unit represented by the formula (III) include the following.

  Among these, for example, (meth) acrylic acid 3-hydroxy-1-adamantyl, (meth) acrylic acid 3, 5-dihydroxy-1-adamantyl, methacrylic acid 1- (3-hydroxy-1-adamantyloxycarbonyl) methyl Preferred examples include 1- (3,5-dihydroxy-1-adamantyloxycarbonyl) methyl methacrylate and the like.

  As the structural unit represented by the formula (II), for example, a plurality of structural units having a lactone structure in the side chain may be included. Specific examples include a compound having a β-butyrolactone structure, a compound having a γ-butyrolactone structure, and a compound having a lactone structure added to a cycloalkyl skeleton or a norbornane skeleton.

  Among these, for example, a structural unit represented by any one of the formula (IVa), the formula (IVb), and the formula (IVc) can be preferably exemplified.

[In Formula (IVa) to Formula (IVc), R ⁴¹ represents a hydrogen atom or a methyl group.
R ⁹ represents a hydrogen atom or a methyl group.
l represents an integer of 1 to 5. When l is 2 or more, the plurality of R ⁹ may be the same as or different from each other.
R ¹⁰ and R ¹¹ each independently represent a carboxyl group, a cyano group, or a hydrocarbon group having 1 to 4 carbon atoms.
l ′ represents an integer of 0 to 3. When l ′ is 2 or more, the plurality of R ¹⁰ and R ¹¹ may be the same as or different from each other.
Z ″ represents the same meaning as in formula (IIa). ]

  Specific examples of the monomer for deriving the structural unit represented by the formula (IVa) include the following.

  Specific examples of the monomer for deriving the structural unit represented by the formula (IVb) include the following.

  Specific examples of the monomer for deriving the structural unit represented by the formula (IVc) include the following.

  Among these, for example, (meth) acrylic acid hexahydro-2-oxo-3,5-methano-2H-cyclopenta [b] furan-6-yl, (meth) acrylic acid tetrahydro-2-oxo-3-furyl, Preferred examples include resins obtained from 2- (5-oxo-4-oxatricyclo [4.2.1.03.7] nonan-2-yloxy) -2-oxoethyl (meth) acrylate.

  Moreover, as resin, you may have structural units other than the structural unit represented, for example by Formula (II). Examples of the structural unit other than the structural unit represented by the formula (II) include a structural unit derived from 2-norbornene. 2-norbornene may be introduced into the main chain during polymerization by radical polymerization using, for example, an aliphatic unsaturated dicarboxylic anhydride such as maleic anhydride or itaconic anhydride in addition to the corresponding 2-norbornene. Good. The structural unit derived from 2-norbornene is formed by opening a double bond of the norbornene structure and can be represented by the formula (d). The structural unit derived from maleic anhydride and itaconic anhydride is formed by opening a double bond of maleic anhydride and itaconic anhydride, and can be represented by the formulas (e) and (f), respectively.

Here, R ²⁵ and R ²⁶ in the formula (d) are independently of each other a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 3 carbon atoms, a carboxyl group, a cyano group, or —COOU. (U is an alcohol residue), or R ²⁵ and R ²⁶ together represent a carboxylic acid anhydride residue which is a ring containing —C (═O) OC (═O) —. Represents a group.
The —COOU is an ester of a carboxyl group, and examples of the alcohol residue corresponding to U include, for example, an optionally substituted linear or branched aliphatic carbon carbon atom having 1 to 8 carbon atoms. A hydrogen group, 2-oxooxolane-3- or -4-yl group, etc. can be mentioned. Here, as a substituent of the aliphatic hydrocarbon group, a hydroxyl group or an alicyclic hydrocarbon residue having 4 to 36 carbon atoms may be bonded.
Examples of the aliphatic hydrocarbon group for R ²⁵ and R ²⁶ include a methyl group, an ethyl group, and a propyl group. Examples of the aliphatic hydrocarbon group to which a hydroxyl group is bonded include a hydroxymethyl group and a 2-hydroxyethyl group. Etc.

Specific examples of the monomer for deriving the structural unit having norbornene represented by the formula (d) include the following.
2-norbornene,
2-hydroxy-5-norbornene,
5-norbornene-2-carboxylic acid,
Methyl 5-norbornene-2-carboxylate,
2-hydroxy-1-ethyl 5-norbornene-2-carboxylate,
5-norbornene-2-methanol,
5-norbornene-2,3-dicarboxylic anhydride.

  In addition, about U of —COOU in the formula (d), a norbornene structure is used as long as it is an acid-labile group such as an alicyclic ester in which the carbon atom bonded to the oxygen side of the carboxyl group is a quaternary carbon atom. Is a structural unit having an acid labile group. Examples of the monomer containing a norbornene structure and an acid labile group include, for example, 5-norbornene-2-carboxylic acid-t-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, 5- 1-methylcyclohexyl norbornene-2-carboxylate, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantyl 5-norbornene-2-carboxylate, 5-norbornene-2-carboxyl Acid 1- (4-methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl-1 -(4-oxocyclohexyl) ethyl, 5-norbornene-2-carboxylic acid 1- (1-adap Pentyl) -1-methylethyl and the like.

  In addition to the resin (B), a resin known in the technical field of ArF resist can be used in combination with the resin in the present invention.

  Moreover, this invention resist composition contains a basic compound. Examples of basic compounds include the following.

In the formula, T ¹ , T ² and T ⁷ are each independently a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alicyclic hydrocarbon having 5 to 10 carbon atoms. Represents a group or an aromatic hydrocarbon group having 6 to 20 carbon atoms. The hydrogen atom of the aliphatic hydrocarbon group, the hydrogen atom of the alicyclic hydrocarbon group, and the hydrogen atom of the aromatic hydrocarbon group are a hydroxyl group, an amino group, or a linear or branched alkoxy group having 1 to 6 carbon atoms. May be substituted. The hydrogen atom of the amino group may be substituted with a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms.

T ^{3 to} T ⁵ are each independently a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or 6 to 6 carbon atoms. 20 represents an aromatic hydrocarbon group or a linear or branched alkoxy group having 1 to 6 carbon atoms. The hydrogen atom of the aliphatic hydrocarbon group, the hydrogen atom of the alicyclic hydrocarbon group, the hydrogen atom of the aromatic hydrocarbon group and the hydrogen atom of the alkoxy group are independently of each other a hydroxyl group, an amino group, or a direct atom. It may be substituted with a linear or branched alkoxy group having 1 to 6 carbon atoms. The hydrogen atom of the amino group may be substituted with a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms.

T ⁶ represents a linear or branched aliphatic hydrocarbon group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 10 carbon atoms. The hydrogen atom of the aliphatic hydrocarbon group and the hydrogen atom of the alicyclic hydrocarbon group are independently substituted with a hydroxyl group, an amino group, a linear or branched alkoxy group having 1 to 6 carbon atoms. May be. The hydrogen atom of the amino group may be substituted with a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms.

  G represents a linear or branched alkylene group having 2 to 6 carbon atoms, a carbonyl group, an imino group, a sulfide group or a disulfide group.

  Specific examples of such compounds include hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, 1- or 2-naphthylamine. , Ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3 '-Diethyldiphenylmethane, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, N-methylaniline, piperidine, diphenylamine, triethylamine, trimethylamine, tripropylamine, tripropylamine Tylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine , Methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, N, N-dimethylaniline, 2,6-isopropylaniline, imidazole, Gin, 4-methylpyridine, 4-methylimidazole, bipyridine, 2,2'-dipyridylamine, di-2-pyridyl ketone, 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ) Ethane, 1,3-di (4-pyridyl) propane, 1,2-bis (2-pyridyl) ethylene, 1,2-bis (4-pyridyl) ethylene, 1,2-bis (4-pyridyloxy) Ethane, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide, 1,2-bis (4-pyridyl) ethylene, 2,2′-dipiconylamine, 3,3′-dipiconylamine, tetramethyl Ammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra-n-hexylammonium hydroxide, tet Examples include la-n-octylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethylammonium hydroxide, and choline.

  Furthermore, a hindered amine compound having a piperidine skeleton as disclosed in JP-A-11-52575 can be used as a quencher.

  More preferable quenchers include compounds represented by the formula (XII). Specifically, for example, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-trifluoromethyl-phenyltrimethylammonium hydroxide, etc. Can be mentioned.

  The resist composition of the present invention may usually contain a resin in the range of about 80 to 99% by mass and an acid generator in the range of about 1 to 20% by mass based on the total solid content.

  When the resist composition of the present invention contains a basic compound as a quencher, the content of the basic compound is usually 0.01 to 5% by mass based on the total solid content of the resist composition of the present invention. The range of the degree.

The resist composition of the present invention contains a solvent.
Examples of the solvent include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate, acetone, methyl isobutyl ketone , Ketones such as 2-heptanone and cyclohexanone, cyclic esters such as γ-butyrolactone, and propylene glycol monomethyl ether. These solvents can be used alone or in combination of two or more.

The resist composition of the present invention contains a surfactant.
Examples of the surfactant include at least one surfactant selected from the group consisting of silicone surfactants, fluorine surfactants, and silicone surfactants having fluorine atoms.
Examples of silicone surfactants include surfactants having a siloxane bond. Specifically, Torre Silicone DC3PA (trade name), Torre Silicone SH7PA (trade name), Torre Silicone DC11PA (trade name), Torre Silicone SH21PA (trade name), Torre Silicone SH28PA (trade name), Torre Silicone 29SHPA (Product) Name), Torre Silicone SH30PA (trade name), polyether-modified silicone oil SH8400 (trade name) (manufactured by Torre Silicone Co., Ltd.), KP321 (trade name), KP322 (trade name), KP323 (trade name), KP324 ( Product Name), KP326 (Product Name), KP340 (Product Name), KP341 (Product Name) (made by Shin-Etsu Silicone), TSF400 (Product Name), TSF401 (Product Name), TSF410 (Product Name), TSF4300 (Product Name) , TSF4440 (trade name) TSF4445 (trade name), TSF-4446 (trade name), TSF4452 (trade name), TSF4460 (trade name) (manufactured by GE Toshiba Silicones Co., Ltd.), and the like.
Examples of the fluorosurfactant include a surfactant having a fluorocarbon chain. Specifically, Florinert FC430 (trade name), Florinart FC431 (trade name) (manufactured by Sumitomo 3M Co., Ltd.), Megafuck F142D (trade name), Megafuck F171 (trade name), Megafuck F172 (trade name) , Megafuck F173 (trade name), Megafuck F177 (trade name), Megafuck F183 (trade name), Megafuck R30 (trade name) (manufactured by Dainippon Ink & Chemicals, Inc.), Ftop EF301 (trade name) ), Ftop EF303 (product name), Ftop EF351 (product name), Ftop EF352 (product name) (manufactured by Shin-Akita Kasei Co., Ltd.), Surflon S381 (product name), Surflon S382 (product name), Surflon SC101 (trade name), Surflon SC105 (trade name) (manufactured by Asahi Glass Co., Ltd.), E5844 ( Name) (Co., Ltd. Daikin Fine Chemical Institute), BM-1000 (trade name), BM-1100 (trade name) (BM Chemie Co., Ltd.) and the like.
Examples of the silicone-based surfactant having a fluorine atom include a surfactant having a siloxane bond and a fluorocarbon chain. Specifically, Mega Fuck R08 (trade name), Mega Fuck BL20 (trade name), Mega Fuck F475 (trade name), Mega Fuck F 477 (trade name), Mega Fuck F 443 (trade name) (Dainippon Ink and Chemicals, Inc.) Etc.).
These surfactants may be used alone or in combination of two or more.
Among these, silicone-based surfactants are preferable, and polyether-modified silicone oil SH8400 (trade name) (manufactured by Torre Silicone Co., Ltd.) is particularly preferable.
The content of the surfactant is a mass fraction with respect to the composition, preferably 0.0005% by mass to 0.10% by mass, more preferably 0.0010% by mass to 0.05% by mass, especially Preferably they are 0.0015 mass% or more and 0.03 mass% or less. It is preferable that the content of the surfactant is in the above range because the flatness of the obtained coating film tends to be further improved.

  The resist composition of the present invention can further contain a small amount of various additives such as a sensitizer, a dissolution inhibitor, other resins, stabilizers, and dyes, if necessary.

The present invention also provides a pattern forming method including the following steps.

(1) Step of applying the resist composition of the present invention on a substrate (2) Step of forming a composition layer by removing the solvent from the composition after coating (3) Using an immersion exposure machine for the composition layer Step of exposing (4) Step of heating composition layer after exposure (5) Step of developing composition layer after heating using developing device

As the substrate, a silicon wafer is usually used.
Application of the resist composition onto the substrate is performed by a commonly used apparatus such as a spin coater.
The removal of the solvent is performed by heating the solvent using a heating device such as a hot plate, or the composition layer from which the solvent has been removed is formed using a decompression device. The heating is performed, for example, by heating at a temperature of 80 to 140 ° C. for 30 seconds to 10 minutes. When using a decompression device, for example, the solvent is removed at a temperature of about 10 to 100 ° C. and a pressure of about 1 to 1.0 × 10 ⁵ Pa.
The composition layer obtained by removing the solvent is exposed using an immersion exposure machine. Examples of the exposure conditions include a scanning exposure type projection exposure apparatus (exposure apparatus) that is a scanning exposure type. As the exposure light source, various light sources such as an ArF excimer laser (wavelength of 193 nm) that emits laser light in the ultraviolet region can be used.
The liquid between the lens of the exposure machine used for immersion exposure and the wafer is usually water, but a liquid for immersion exposure can be used instead of water.
At this time, exposure is usually performed through a mask corresponding to a required pattern.
The composition layer after the exposure is subjected to heat treatment for promoting the deprotection group reaction. The said heating is performed by heating for 30 second-10 minutes at the temperature of 70-140 degreeC, for example.
The composition layer after heating is developed with a developer using a developing device. The developer used here can be various alkaline solutions used in this field. For example, alkaline aqueous solutions such as tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) are used. Etc.
After development, the substrate is rinsed with ultrapure water, and water remaining on the substrate and the pattern is removed to obtain a pattern.
The resist composition of the present invention can also be suitably used for double imaging.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
In Examples and Comparative Examples,% and part representing the amount used are based on mass unless otherwise specified.

  The weight average molecular weight is a value determined by gel permeation chromatography under the following conditions.

Apparatus: HLC-8120GPC (manufactured by Tosoh Corporation)
Column: 3 TSKgel Multipore HXL-M + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μL
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

  The structure of the compound is NMR (GX-270 type or EX-270 type; manufactured by JEOL Ltd.), mass spectrometry (LC is Agilent 1100 type, MASS is Agilent LC / MSD type or LC / MSD TOF. Type).

(Synthesis of acid generator (A1))
To 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 150 parts of ion-exchanged water, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. This was refluxed at 100 ° C. for 3 hours, cooled, and then neutralized with 88 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 164.4 parts of difluorosulfoacetate / sodium salt (containing inorganic salt, purity 62.7%). To 1.9 parts of the obtained difluorosulfoacetic acid / sodium salt (purity 62.7%) and 9.5 parts of N, N-dimethylformamide, 1.0 part of 1,1′-carbonyldiimidazole was added, Stir for hours to give a mixture.
On the other hand, 0.2 part of sodium hydride was added to 1.1 parts of 3-hydroxyadamantyl methanol and 5.5 parts of N, N-dimethylformamide, and stirred for 2 hours to prepare a solution. To this solution was added the above mixture. The resulting mixture was stirred for 15 hours, and the resulting solution containing difluorosulfoacetate-3-hydroxy-1-adamantylmethyl ester / sodium salt was directly used in the next reaction. To the obtained solution containing difluorosulfoacetic acid-3-hydroxy-1-adamantylmethyl ester sodium salt, 17.2 parts of chloroform and 2.9 parts of a 14.8% aqueous solution of triphenylsulfonium chloride were added. After stirring for 15 hours, the organic layer was recovered by liquid separation. Subsequently, the remaining aqueous layer was extracted with 6.5 parts of chloroform to recover the organic layer. The organic layers were combined, washed with ion-exchanged water, and then the obtained organic layer was concentrated. To the concentrate, 5.0 parts of tert-butyl methyl ether was added, stirred and filtered to give triphenylsulfonium 1-((3-hydroxyadamantyl) methoxycarbonyl) difluoromethanesulfonate (A1) as a white solid. Two parts were obtained. The fluorine content in (A1) was 6.30% by mass.

(Synthesis of acid generator (A2))
To 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 250 parts of ion-exchanged water, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The resulting mixture was refluxed at 100 ° C. for 3 hours, cooled, and neutralized with 88 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 164.8 parts of difluorosulfoacetic acid / sodium salt (containing inorganic salt, purity 62.6%). To the obtained difluorosulfoacetic acid / sodium salt 5.0 parts (purity 62.6%), 4-oxo-1-adamantanol 2.6 parts and ethylbenzene 100 parts, 0.8 parts of concentrated sulfuric acid was added for 30 hours. Heated to reflux. The resulting mixture is cooled and then filtered to collect a filtration residue. The collected filtration residue is washed with tert-butyl methyl ether to obtain difluorosulfoacetic acid-4-oxo-1-adamantyl ester sodium salt 5 .5 parts were obtained. As a result of purity analysis by ¹ H-NMR, the purity was 35.6%. 16 parts of acetonitrile and 16 parts of ion-exchanged water were added to 5.4 parts (purity 35.6%) of the obtained difluorosulfoacetic acid-4-oxo-1-adamantyl ester sodium salt. To the obtained mixture, 1.7 parts of triphenylsulfonium chloride, 5 parts of acetonitrile and 5 parts of ion-exchanged water were added. The resulting mixture was stirred for 15 hours and then concentrated, and the resulting mixture was extracted with 142 parts of chloroform to recover the organic layer. The collected organic layer was washed with ion-exchanged water, and then the obtained organic layer was concentrated. The concentrate was repulped with 24 parts of tert-butyl methyl ether to obtain 1.7 parts of triphenylsulfonium 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate (A2) as a white solid. The fluorine content in (A2) was 6.48% by mass.

(Synthesis of acid generator (A3))
To 200 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 300 parts of ion-exchanged water, 460 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The resulting mixture was refluxed at 100 ° C. for 2.5 hours, cooled, and neutralized with 175 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 328.19 parts of difluorosulfoacetate sodium salt (the content rate was 63.5% because the inorganic salt was not removed). 24.0 parts of p-toluenesulfonic acid was added to a mixture of 39.4 parts (content 63.5%) of difluorosulfoacetic acid sodium salt, 21.0 parts of 1-adamantane methanol and 200 parts of dichloroethane, Was heated to reflux for 7 hours. Then, it concentrated and dichloroethane was distilled off, 250 parts of tert-butyl methyl ether was added to the concentration residue, and after repulping, it filtered and the filtration residue was collect | recovered. After adding 250 parts of acetonitrile to the collected filtration residue and stirring, the filtrate was collected by filtration, and the collected filtrate was concentrated to obtain 32.8 difluorosulfoacetic acid-1-adamantylmethyl ester sodium salt 32.8. Got a part. To a solution obtained by dissolving 32.8 parts of the obtained difluorosulfoacetic acid-1-adamantyl methyl ester / sodium salt in 100 parts of ion-exchanged water, 28.3 parts of triphenylsulfonium chloride and 140 parts of methanol were added. Added. The resulting mixture was stirred at 23 ° C. for 15 hours and then concentrated, and the resulting concentrate was extracted twice with 200 parts of chloroform. The recovered organic layers obtained by the extraction twice were combined, and the washing operation using ion-exchanged water was repeated until the organic layer became neutral, and then the obtained organic layer was concentrated. To the concentrated solution, 300 parts of tert-butyl methyl ether was added, stirred, and then filtered to collect a white precipitate, which was dried under reduced pressure to give triphenylsulfonium 1-adamantylmethoxycarbonyldifluoromethanesulfone as white crystals. 39.7 parts of Nert (A3) were obtained. The fluorine content in (A3) was 6.48% by mass.

(Synthesis of acid generator (A4))
To 200 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 300 parts of ion-exchanged water, 460 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. This was refluxed at 100 ° C. for 2.5 hours, cooled, and then neutralized with 175 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 328.19 parts of difluorosulfoacetic acid / sodium salt (containing inorganic salt, purity 62.8%). To a mixture of the obtained difluorosulfoacetic acid / sodium salt 123.3 parts (purity 62.8%), 1-adamantane methanol 65.7 parts and dichloroethane 600 parts, 75.1 parts of p-toluenesulfonic acid was added. Was heated to reflux for 12 hours. Then, it concentrated and the dichloroethane was distilled off, 400 parts of tert- butyl methyl ether was added to the concentration residue, and after repulping, it filtered and the filtration residue was collect | recovered. 400 parts of acetonitrile was added to the collected filtration residue, and after stirring, filtration was repeated twice and concentrated to obtain 99.5 parts of difluorosulfoacetic acid-1-adamantylmethyl ester sodium salt.
Next, 150 parts of 2-bromoacetophenone was dissolved in 375 parts of acetone, and 66.5 parts of tetrahydrothiophene was added dropwise thereto. After stirring the resulting mixture at room temperature for 24 hours, the white precipitate formed was collected by filtration, washed with acetone and then dried to give 1- (2-oxo-2-phenyl) as white crystals. 207.9 parts of ethyl) tetrahydrothiophenium bromide were obtained.
99.5 parts of difluorosulfoacetic acid-1-adamantyl methyl ester / sodium salt obtained above was dissolved in 298 parts of acetonitrile. To the obtained solution, 79.5 parts of 1- (2-oxo-2-phenylethyl) tetrahydrothiophenium bromide obtained above and 159 parts of ion-exchanged water were added. The resulting mixture was stirred at room temperature for 15 hours and then concentrated, and the resulting concentrate was extracted twice with 500 parts of chloroform. The organic layers recovered by the two extractions were combined, washed with ion-exchanged water, and the obtained organic layer was concentrated. To the concentrated liquid, 250 parts of tert-butyl methyl ether was added, stirred, and then filtered to collect a white precipitate, which was dried under reduced pressure to give 1- (2-oxo-2-phenylethyl as white crystals. ) 116.9 parts of tetrahydrothiophenium 1-adamantylmethoxycarbonyldifluoromethanesulfonate (A4) were obtained. The fluorine content in (A4) was 7.16% by mass.

(Synthesis of acid generator A7)
3.51 parts of 3-hydroxy-1-adamantanecarboxylic acid and 75 parts of anhydrous THF were charged and stirred at 23 ° C. for 30 minutes. Next, a mixed solution of 2.89 parts of carbonyldiimidazole and 50 parts of anhydrous THF was added dropwise at 23 ° C., and the mixture was stirred at 23 ° C. for 4 hours. The obtained reaction solution was dropped into a mixed solution of 2,2-difluoro-2-sulfoethanol sodium salt 6.04 parts (purity 60%) and anhydrous THF 50 parts at 54-60 ° C. over 25 minutes, Heated at 65 ° C. for 18 hours, cooled and filtered. The obtained filtrate was concentrated, and the concentrate was fractionated into a column (Merck silica gel 60-200 mesh developing solvent: chloroform / methanol = 5/1) to obtain sodium 3-hydroxy-1-adamantylcarbonyloxymethyldifluoromethanesulfone. 2.99 parts of nat were obtained.
Sodium 3-hydroxy-1-adamantylcarbonyloxymethyldifluoromethanesulfonate (1.0 part) and chloroform (30 parts) were charged and stirred at 23 ° C. for 30 minutes. Next, 0.94 parts of tris (4-methylphenyl) sulfonium chloride, 8.6 parts of chloroform, and 2.5 parts of ion-exchanged water were stirred at 23 ° C. for 12 hours, followed by liquid separation. 10 parts of ion-exchanged water was added to the organic layer, followed by liquid separation washing. This operation was performed three times. Thereafter, 1 part of magnesium sulfate was added and stirred at 23 ° C. for 30 minutes, followed by filtration. The filtrate was concentrated to obtain 0.89 part of compound (A7). The fluorine content in (A7) was 5.89% by mass.

(Synthesis of resin (B1))
Monomer A, monomer B, monomer C and monomer D were charged in a molar ratio of 35: 15: 20: 30, and then 1.5 mass times dioxane was added to the total mass of all monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were used as initiators at a ratio of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. This was added and heated at 77 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent and precipitating three times to obtain a copolymer having a weight average molecular weight of about 8100 in a yield of 78%. The obtained copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B1.

After mixing the following components with the composition shown in Table 1, the obtained mixture was filtered through a fluororesin filter having a pore diameter of 0.2 μm to prepare a resist composition.
The fluorine content in the solid content of the composition was calculated by the following formula.
100 × (fluorine content in the solid content of the composition)
Fluorine content = ――――――――――――――――――――――
(Solid content of composition)
The solid content of the composition was determined by summing the amounts of components other than the solvent contained in the composition.
The fluorine content in the solid content of the composition was determined by calculating the fluorine content of each component other than the solvent.
The fluorine content in the acid generator was calculated by the following formula.
Fluorine content in acid generator 100 × (number of fluorine atoms per molecule of acid generator) × (atomic weight of fluorine atoms)
= ――――――――――――――――――――――――――――――――――――
(Molecular weight of acid generator)

<Acid generator>
Acid generator; A1-A4, A7
A5: Fluorine content: 0.00% by mass
A6: Fluorine content; 0.00% by mass

C1: Triphenylsulfonium trifluoromethanesulfonate (fluorine content: 15.14% by mass)
C2: Triphenylsulfonium pentafluoroethanesulfonate (fluorine content: 22.28% by mass)
C3: Triphenylsulfonium perfluorobutanesulfonate (fluorine content: 32.48% by mass)
C4: Triphenylsulfonium perfluorooctanesulfonate (fluorine content: 44.46% by mass)
<Resin>
Resin B1
<Basic compound>
Q1: 2,6-diisopropylaniline <solvent>
Propylene glycol monomethyl ether acetate 265 parts 2-heptanone 20.0 parts Propylene glycol monomethyl ether 20.0 parts γ-butyrolactone 3.5 parts <Surfactant>
SH8400 25ppm (in composition)

<Foreign matter evaluation>
The resist composition was spin-coated on a 12-inch silicon wafer so that the film thickness after drying was 0.15 μm. After applying the resist composition, it was pre-baked at 100 ° C. for 60 seconds on a direct hot plate. The wafer on which the resist composition film was thus formed was subjected to water rinsing for 60 seconds using a developing machine [ACT-12; manufactured by Tokyo Electron Ltd.].
Thereafter, the number of defects on the wafer is measured using a defect inspection apparatus [KLA-2360; manufactured by KLA Tencor], and the number of defects is determined to be 1000 or less as ◯, 10000 or more as x, and exceeding 1000 and less than 10000 as Δ. did. The results are shown in Table 2.

<Pattern evaluation>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 780 mm. An organic antireflection film was formed. Subsequently, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying was 0.15 μm. After application of the resist composition, it was pre-baked at 100 ° C. for 60 seconds on a direct hot plate. Using the ArF excimer stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35], the exposure amount is changed stepwise on the wafer on which the resist composition film has been formed. Was subjected to immersion exposure.
After exposure, the wafer on which the pattern was formed was post-exposure baked on a hot plate at 105 ° C. for 60 seconds, and further paddle developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds. Further, the developed wafer was rinsed with ultrapure water.
Of the patterns formed on the wafer, the resist pattern exposed with an exposure amount that makes a 70 nm line and space pattern 1: 1 is observed with a defect inspection apparatus [KLA-810; manufactured by KLA Tencor], and foreign matter is found in the pattern. Those with attached were judged as defective and marked with ×, and those with a pattern formed normally were judged good and marked with ○.
The results are shown in Table 2.

[Table 1]
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Example No. Composition Resin Acid generator Quencher Fluorine content
(mass%)
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Example 1 Composition 1 B1 / 10 part A1 / 0.55 part Q1 / 0.07 part 0.33
Example 2 Composition 2 B1 / 10 part A2 / 0.55 part Q1 / 0.07 part 0.34
Example 3 Composition 3 B1 / 10 part A3 / 0.55 part Q1 / 0.07 part 0.34
Example 4 Composition 4 B1 / 10 part A4 / 0.55 part Q1 / 0.07 part 0.37
Example 5 Composition 5 B1 / 10 part A5 / 1.20 part Q1 / 0.07 part 0.00
Example 6 Composition 6 B1 / 10 part A6 / 1.50 part Q1 / 0.07 part 0.00
Example 7 Composition 7 B1 / 10 part A1 / 0.18 part Q1 / 0.03 part 0.11
Example 8 Composition 8 B1 / 10 part A1 + A6 / 0.18 + 0.18 part Q1 / 0.05 part 0.11
Example 9 Composition 9 B1 / 10 part A1 / 0.70 part Q1 / 0.07 part 0.41
Example 10 Composition 10 B1 / 10 part A1 / 0.85 part Q1 / 0.07 part 0.49
Example 11 Composition 11 B1 / 10 part A7 / 0.55 part Q1 / 0.07 part 0.31
Reference Example 1 Composition 7 B1 / 10 part C1 / 0.40 part Q1 / 0.07 part 0.58
Reference Example 2 Composition 8 B1 / 10 part C2 / 0.45 part Q1 / 0.07 part 0.95
Reference Example 3 Composition 9 B1 / 10 part C3 / 0.55 part Q1 / 0.07 part 1.68
Reference Example 4 Composition 10 B1 / 10 part C4 / 0.70 part Q1 / 0.07 part 2.89
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[Table 2]
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Example No. Foreign matter evaluation Pattern evaluation ━━━━━━━━━━━━━━━━━━
Example 1
Example 2
Example 3 ○ ○
Example 4 ○ ○
Example 5
Example 6
Example 7 ○ ○
Example 8
Example 9
Example 10
Example 11
Reference Example 1 × ×
Reference Example 2 × ×
Reference Example 3 × ×
Reference Example 4 × ×
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<Shape evaluation>

An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 780 mm. An organic antireflection film was formed. Subsequently, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying was 85 nm.
After applying the resist composition, the obtained silicon wafer was pre-baked (PB) for 60 seconds at a temperature described in the “PB” column of Table 1 on a direct hot plate. Using the ArF excimer stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] on the wafer on which the resist composition film is thus formed, the exposure amount is stepwise. The line and space pattern was subjected to immersion exposure.
After the exposure, post-exposure baking (PEB) was performed for 60 seconds on a hot plate at the temperature described in the “PEB” column of Table 1, and further with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed.

  In each resist film, the exposure amount at which the 50 nm line and space pattern becomes an exposure amount of 1: 1 was defined as the effective sensitivity.

Shape evaluation: A 50 nm line and space pattern was observed with a scanning electron microscope. A case where the top shape and the skirt shape were close to a rectangle was good, and a case where the top shape was round or close to a T-shape, a skirt was seen, or a case where it was not missing was judged as △.
The results are shown in Table 3.

[Table 3]
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Example No. Shape evaluation
━━━━━━━━━━━━━━━━━━━
Example 1 ○
Example 2 ○
Example 3 ○
Example 4 ○
Example 5
Example 6
Example 7 ○
Example 8 ○
Example 9 ○
Example 10 ○
━━━━━━━━━━━━━━━━━━━

  The chemically amplified photoresist composition of the present invention can form a pattern with less foreign matter generated when the resist film comes into contact with water.

Claims (9)

  A chemically amplified photoresist composition for immersion exposure containing an acid generator, a resin, a basic compound, a solvent, and a surfactant, and the fluorine content in the solid content of the composition is 0.5% by mass or less. The composition characterized by these.   The composition according to claim 1, wherein a fluorine content in the acid generator is 10% by mass or less. The composition according to claim 1 or 2, wherein the acid generator is a compound represented by the formula (a).
[In the formula (a), Z ⁺ represents an organic cation.
A represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 36 carbon atoms. The hydrogen atom contained in the aromatic hydrocarbon group and the linear, branched or cyclic hydrocarbon group is a halogen atom, a hydroxyl group, a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms. A linear or branched alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, a glycidoxy group, or an acyl group having 2 to 4 carbon atoms. The methylene group contained in the alicyclic hydrocarbon group, the aliphatic hydrocarbon group, the alkoxy group and the aralkyl group may be substituted with an oxygen atom and / or a carbonyl group. . ] The composition according to claim 3, wherein the A is a group represented by the formula (a1) or a group represented by the formula (a2).
Wherein (a1) and the formula (a2), ^{X 1} is a single bond or - _{[CH 2] k} - represents, the - _{[CH 2] k} - methylene group contained in the oxygen atom and / or a carbonyl group in may be substituted, the _- [CH _2] k - a hydrogen atom may be substituted with a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms included. k represents an integer of 1 to 17.
Y ¹ is an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or a linear, branched or cyclic aliphatic carbon group having 1 to 36 carbon atoms which may have a substituent. Represents a hydrogen group, and the methylene group contained in the aliphatic hydrocarbon group may be substituted with an oxygen atom and / or a carbonyl group. However, if Y ¹ is a linear or branched aliphatic hydrocarbon group of the, X ¹ is intended to represent a single bond.
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]   Said (a1) is a C1-C10 perfluoro group, a C1-C4 aliphatic hydrocarbon group which may be substituted with a C1-C4 aromatic hydrocarbon group, C1-C4 The composition according to claim 4, which is an alicyclic hydrocarbon group having 6 to 20 carbon atoms which may be substituted with an aliphatic hydrocarbon group. The composition according to any one of claims 3 to 5, wherein Z ⁺ is a cation represented by the formula (IXa).
[In formula (IXa), P ¹ , P ² and P ³ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched group. Represents an alkoxy group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group includes a halogen atom, a hydroxyl group, and 1 to 1 carbon atoms. It is substituted with 12 alkyl groups, C1-C12 alkoxy groups, C6-C12 aromatic hydrocarbon groups, C7-C12 aralkyl groups, glycidoxy groups, or C2-C4 acyl groups. May be. ]   The composition according to any one of claims 1 to 6, wherein the resin is a resin (B) having a structural unit having an alkali-soluble group, a structural unit having a hydroxyl group, and a structural unit having an acid leaving group. object.   The composition according to any one of claims 1 to 7, wherein the resin further comprises a resin that is not the same as the resin (B) and has a group that becomes alkali-soluble by the action of an acid. A pattern forming method including the following steps.
(1) The process of apply | coating the composition in any one of Claims 1-8 on a board | substrate (2) The process of removing a solvent from the composition after application | coating, and forming a composition layer (3) In a composition layer Step of exposing using immersion exposure machine (4) Step of heating composition layer after exposure (5) Step of developing composition layer after heating using developing device