JP5266688B2 - Salt for acid generator of chemically amplified resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a salt functioning as an acid-generating agent giving a chemically amplified resist composition exhibiting high resolution and wide exposure margin. <P>SOLUTION: The salt is expressed by formula (I) (Q<SP>1</SP>and Q<SP>2</SP>are each independently a fluorine atom or a 1-6C perfluoroalkyl group; X is a 1-12C straight or branched-chain bivalent hydrocarbon group; Y is a 1-30C hydrocarbon group which may have substituents; and A<SP>+</SP>is an organic counter ion). <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a salt used as an acid generator contained in a chemically amplified resist composition used in a chemically amplified resist composition used for fine processing of semiconductors.

A chemically amplified resist composition used for fine processing of a semiconductor using a lithography technique contains an acid generator composed of a compound that generates an acid upon exposure.
In microfabrication of semiconductors, high resolution is desirable, and a chemical amplification resist composition is required to exhibit high resolution.

  Recently, a chemically amplified resist composition comprising triphenylsulfonium 1-adamantanemethoxycarbonyldifluoromethanesulfonate (salt) and p-tolyldiphenylsulfonium perfluorooctanesulfonate (salt) as an acid generator has been proposed. However, there has been a demand for a salt serving as an acid generator that provides a chemically amplified resist composition that exhibits high resolution and good exposure margin (see, for example, Patent Document 1). The exposure margin represents a change in pattern dimension with respect to a change in exposure amount, and a smaller value is better.

Japanese Patent Laid-Open No. 2004-4561

  An object of the present invention is to provide a salt as an acid generator that provides a chemically amplified resist composition exhibiting high resolution and good exposure margin.

  Therefore, in order to solve the above-mentioned problems, the present inventors have intensively studied a salt used as an acid generator contained in a chemically amplified resist composition. As a result, a group containing a chain hydrocarbon group, a further ester The inventors have found that a specific salt having a group can be an acid generator that provides a chemically amplified resist composition exhibiting high resolution and a good exposure margin, thereby completing the present invention.

（式（Ｉ）中、Ｑ¹およびＱ²は互いに独立にフッ素原子又は炭素数１〜６のペルフルオロアルキル基を表し、Ｘは炭素数１〜１２の２価の基であって直鎖または分岐の鎖状炭化水素基を表し、Ｙは炭素数１〜３０の置換されていてもよい炭化水素基を表す。Ａ⁺は有機対イオンを表す。） That is, the present invention provides a salt represented by the formula (I).

(In the formula (I), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and X is a C 1-12 divalent group, linear or branched. And Y represents an optionally substituted hydrocarbon group having 1 to 30 carbon atoms, and A ⁺ represents an organic counter ion.)

  Moreover, this invention provides the acid generator which uses the salt shown by Formula (I) as an active ingredient.

（式（Ｖ）中、Ｑ¹およびＱ²は互いに独立にフッ素原子又は炭素数１〜６のペルフルオロアルキル基を表し、Ｘは炭素数１〜１２の２価の基であって直鎖または分岐の鎖状炭化水素基を表し、Ｙは炭素数１〜３０の置換されていてもよい炭化水素基を表す。Ｍは、Ｌｉ、Ｎａ、Ｋ又はＡｇを表す。） Moreover, this invention provides the salt shown by the formula (V) which can be used for manufacture of the salt shown by the formula (I).

(In formula (V), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and X is a C 1-12 divalent group, linear or branched. And Y represents an optionally substituted hydrocarbon group having 1 to 30 carbon atoms, and M represents Li, Na, K, or Ag.)

（式（ＶI）中、Ｘ及びＹは前記と同じ意味を表す。ＺはＣｌ、Ｂｒ又はＩを表す。）
式（ＶII）

（式（ＶII）中、Ｑ¹、Ｑ²およびＭは、前記と同じ意味を表す。）
で示されるカルボン酸とを反応させることを特徴とする式（Ｖ）で示される塩の製造方法を提供する。 The present invention also provides a compound represented by formula (VI):

(In formula (VI), X and Y represent the same meaning as described above. Z represents Cl, Br or I.)
Formula (VII)

(In formula (VII), Q ¹ , Q ² and M represent the same meaning as described above.)
A method for producing a salt represented by the formula (V) is provided, which comprises reacting with a carboxylic acid represented by formula (V).

（式（ＶIII）中、Ａ⁺は、前記と同じ意味を表し、ＬはＦ、Ｃｌ、Ｂｒ、Ｉ、ＢＦ₄、ＡｓＦ₆、ＳｂＦ₆、ＰＦ₆又はＣｌＯ₄を表す。） The present invention also provides a method for producing a salt represented by the formula (I) in which a salt represented by the formula (V) is reacted with a compound represented by the formula (VIII).

(In formula (VIII), A ⁺ represents the same meaning as described above, and L represents F, Cl, Br, I, BF ₄ , AsF ₆ , SbF ₆ , PF _6, or ClO _4. )

（式（ＩＸ）中、Ｑ¹、Ｑ²およびＡ⁺は、前記と同じ意味を表す。）
式（ＶＩ）で示される化合物とを反応させることを特徴とする式（Ｉ）で示される塩の製造方法を提供する。

（式（ＶＩ）中、ＸおよびＹ前記と同じ意味を表す。ＺはＣｌ、Ｂｒ又はＩを表す。） The present invention also provides a salt represented by the formula (IX)

(In formula (IX), Q ¹ , Q ² and A ⁺ represent the same meaning as described above.)
Provided is a method for producing a salt represented by the formula (I), which comprises reacting a compound represented by the formula (VI).

(In formula (VI), X and Y represent the same meaning as described above. Z represents Cl, Br or I.)

  Further, the present invention is a resin composition containing a salt represented by formula (I) and a resin, the resin having an acid-labile group and insoluble or hardly soluble in an alkaline aqueous solution. The resin composition which acts with an acid is a resin which can be dissolved in an alkaline aqueous solution.

  Furthermore, the present invention provides a chemically amplified resist composition comprising the resin composition and a basic organic compound.

  By using the salt of the present invention as an acid generator, a chemically amplified resist composition exhibiting high resolution and a good exposure margin can be produced. Therefore, the present invention is extremely useful industrially.

ここで、式（Ｉ）中、Ｘは炭素数１〜１２の２価の基であって直鎖または分岐の鎖状炭化水素基を表し、Ｙは炭素数１〜３０の置換されていてもよい炭化水素基を表す。Ａ⁺は有機対イオンを表し、Ｑ¹およびＱ²は互いに独立にフッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｑ¹およびＱ²としてはそれぞれ独立にフッ素原子または−ＣＦ₃である場合が好ましく、両方ともフッ素原子の場合が、製造が容易であることから最も好ましい。 The salt of the present invention is represented by the formula (I).

Here, in the formula (I), X represents a divalent group having 1 to 12 carbon atoms and represents a linear or branched chain hydrocarbon group, and Y may be substituted with 1 to 30 carbon atoms. Represents a good hydrocarbon group. A ⁺ represents an organic counter ion, and Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
Q ¹ and Q ² are preferably each independently a fluorine atom or —CF ₃ , and both are most preferably a fluorine atom because production is easy.

Specific examples of X include groups represented by the following formula.

  The hydrocarbon having 1 to 30 carbon atoms represented by Y may be a linear or branched alkyl group, a monocyclic or polycyclic hydrocarbon, and may include a double bond or an aromatic ring. Examples of the cyclic hydrocarbon having 1 to 30 carbon atoms in Y include those containing a cyclopentane skeleton, a cyclohexane skeleton, an adamantane skeleton, a norbornane skeleton, a benzene skeleton, a naphthalene skeleton, an anthracene skeleton, a phenanthrene skeleton, and a fluorene skeleton. .

  A part of Y contained therein may have a carbon atom substituted with an oxygen atom, may form a carbonyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, carbon One or more of a C1-C4 perfluoroalkyl group, a C1-C6 hydroxyalkyl group, a hydroxyl group, or a cyano group may be included as a substituent. The number of carbon atoms in Y includes the number of carbon atoms in the substituent, but does not include the number of oxygen atoms. Moreover, as carbon number of Y, 1-20 are preferable.

Specific examples of Y include a group represented by the following formula.

Specific examples of the anion moiety of the salt represented by the formula (I) include anions represented by the following formula.

In the salt represented by the formula (I), A ⁺ represents an organic counter ion, specifically, represented by any one of the formula (IIa), the formula (IIb), the formula (IIc), or the formula (IId). There may be mentioned at least one cation selected from the group consisting of cations.

式（IIａ）中、Ｐ¹〜Ｐ³は、互いに独立に、直鎖状もしくは分岐状の炭素数１〜３０のアルキル基又は炭素数３〜３０の環式炭化水素基を表す。当該Ｐ¹〜Ｐ³のいずれかがアルキル基である場合には、水酸基、炭素数１〜１２のアルコキシ基又は炭素数３〜１２の環式炭化水素基の一つ以上を置換基として含んでいてもよく、Ｐ¹〜Ｐ³のいずれかが環式炭化水素基である場合には、水酸基、炭素数１〜１２のアルキル基又は炭素数１〜１２のアルコキシ基の一つ以上を置換基として含んでいてもよい。該アルキル基及び該アルコキシ基は、直鎖でも分岐していてもよい。 Here, the formula (IIa) is the following formula.

In formula (IIa), P ^{1 to} P ³ each independently represent a linear or branched alkyl group having 1 to 30 carbon atoms or a cyclic hydrocarbon group having 3 to 30 carbon atoms. When any of the P ^{1 to} P ³ is an alkyl group, it contains one or more of a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or a cyclic hydrocarbon group having 3 to 12 carbon atoms as a substituent. In the case where any of P ^{1 to} P ³ is a cyclic hydrocarbon group, one or more of a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms may be substituted. May be included. The alkyl group and the alkoxy group may be linear or branched.

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. Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group and the like.
Specific examples of the cyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, an adamantyl group, a phenyl group, a naphthyl group, and a fluorenyl group.

式（IIｂ）中、Ｐ⁴およびＰ⁵は、互いに独立に、水素原子、水酸基、炭素数１〜１２のアルキル基又は炭素数１〜１２のアルコキシ基を表し、該アルキル基及び該アルコキシ基は、直鎖でも分岐していてもよい。該アルキル基及び該アルコキシ基は、式（IIａ）のアルキル基及びアルコキシ基と同じ意味を表す。 Formula (IIb) is the following formula.

In formula (IIb), P ⁴ and P ⁵ 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, and the alkyl group and the alkoxy group are They may be linear or branched. The alkyl group and the alkoxy group have the same meaning as the alkyl group and alkoxy group of the formula (IIa).

式（IIｃ）中、Ｐ⁶およびＰ⁷は、互いに独立に、炭素数１〜１２のアルキル基又は炭素数３〜１２のシクロアルキル基を表し、該アルキル基は、直鎖でも分岐していてもよい。該アルキル基の具体例としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、sec−ブチル基、tert−ブチル基、ペンチル基、ヘキシル基、オクチル基、２−エチルヘキシル基などが挙げられる。該シクロアルキル基としては、シクロプロピル基、シクロブチル基、シクロペンチル基、シクロヘキシル基、シクロヘプチル基、シクロデシル基などが挙げられる。また、Ｐ⁶とＰ⁷とが結合してアルキレン基などの炭素数３〜１２の２価の炭化水素基であってもよい。Ｐ⁸が水素原子を表し、Ｐ⁹が炭素数１〜１２のアルキル基、炭素数３〜１２のシクロアルキル基もしくは置換されていてもよい芳香環基を表すか、またはＰ⁸とＰ⁹が結合して炭素数３〜１２の２価の炭化水素基を表す。Ｐ⁹がアルキル基の場合、該アルキル基の具体例としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、sec−ブチル基、tert−ブチル基、ペンチル基、ヘキシル基、オクチル基、２−エチルヘキシル基などが挙げられる。Ｐ⁹がシクロアルキル基の場合、該シクロアルキル基としては、シクロプロピル基、シクロブチル基、シクロペンチル基、シクロヘキシル基、シクロヘプチル基、シクロデシル基などが挙げられる。ここで、式（IIｃ）における２価の炭化水素基に含まれる炭素原子は、その一部が任意に、カルボニル基、酸素原子、硫黄原子に置換されていてもよい。 Formula (IIc) is the following formula.

In formula (IIc), P ⁶ and P ⁷ each independently represent an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms, and the alkyl group is branched even in a straight chain. Also good. 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. Group 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. Further, it may be a divalent hydrocarbon group having 3 to 12 carbon atoms such as an alkylene group bonded to P ⁶ and P ^7. P ⁸ represents a hydrogen atom, P ⁹ represents an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms or an optionally substituted aromatic ring group, or P ⁸ and P ⁹ are It represents a divalent hydrocarbon group having 3 to 12 carbon atoms by bonding. When P ⁹ is an alkyl group, specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. Group, octyl group, 2-ethylhexyl group and the like. When P ⁹ is a cycloalkyl group, 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. Here, a part of carbon atoms contained in the divalent hydrocarbon group in the formula (IIc) may be optionally substituted with a carbonyl group, an oxygen atom, or a sulfur atom.

式（IIｄ）中、Ｐ¹⁰〜Ｐ²¹は、互いに独立に、水素原子、水酸基、炭素数１〜１２のアルキル基又は炭素数１〜１２のアルコキシ基を表し、該アルキル基及び該アルコキシ基は、直鎖でも分岐していてもよい。Ｂは、硫黄原子又は酸素原子を表す。ｋは、０又は１を表す。 Formula (IId) is a following formula.

In formula (IId), 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, and the alkyl group and the alkoxy group are They may be linear or branched. B represents a sulfur atom or an oxygen atom. k represents 0 or 1.

Specific examples of the cation A ^{+ represented by} the formula (IIa) include cations represented by the following formula.

Specific examples of the cation A ^{+ represented by} the formula (IIb) include cations represented by the following formula.

Specific examples of the cation A ^{+ represented by} the formula (IIc) include cations represented by the following formula.

Specific examples of the cation A ^{+ represented by} the formula (IId) include cations represented by the following formula.

式（IIIａ）〜（IIIｃ）中、Ｐ²²〜Ｐ²⁴は互いに独立に、直鎖状又は分岐状の炭素数１〜２０のアルキル基を表すか又はフェニル基以外の炭素数３〜３０の環式炭化水素基を表す。Ｐ²²〜Ｐ²⁴がアルキル基である場合には、水酸基、炭素数１〜１２のアルコキシ基又は炭素数３〜１２の環式炭化水素基の一つ以上を置換基として含んでいてもよく、Ｐ²²〜Ｐ²⁴が環式炭化水素基の場合には、水酸基、炭素数１〜１２のアルキル基又は炭素数１〜１２のアルコキシ基の一つ以上を置換基として含んでいてもよい。Ｐ²⁵〜Ｐ³⁰は、水酸基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基又は炭素数３〜１２の環式炭化水素基を表し、ｌ、ｍ、ｎ、ｏ、ｐおよびｑは、互いに独立に０〜５の整数を表す。 The cation represented by formula (IIa) is a cation represented by any one of formula (IIIa), formula (IIIb) or formula (IIIc), and A ⁺ represents formula (IIIa), formula (IIIb), formula (III) IIIc), at least one cation selected from the group consisting of cations represented by any one of formula (IIb), formula (IIc) and formula (IId) is preferred.

In formulas (IIIa) to (IIIc), P ^{22 to} P ²⁴ each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms, or a ring having 3 to 30 carbon atoms other than a phenyl group. Represents a hydrocarbon group. If P ²² to P ²⁴ is an alkyl group, a hydroxyl group may comprise as one or more substituents of the cyclic hydrocarbon group having 3 to 12 alkoxy group or a carbon number of 1 to 12 carbon atoms, When P ^{22 to} P ²⁴ are cyclic hydrocarbon groups, one or more of a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms may be included as a substituent. P ²⁵ to P ³⁰ represents a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, a cyclic hydrocarbon group having 3 to 12 alkoxy group or a carbon number of 1 to 12 carbon atoms, l, m, n, o, p And q each independently represents an integer of 0 to 5.

式（IＶａ）〜（IＶｃ）中のＰ²⁵〜Ｐ²⁷は、水酸基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基又は炭素数３〜１２の環式炭化水素基を表し、ｌ、ｍおよびｎは、互いに独立に０〜５の整数を表す。Ｒは、炭素数１〜６のアルキル基を表す。 As the salt represented by the formula (I) of the present invention, among them, the salt represented by the formula (IVa), the formula (IVb) and the formula (IVc) gives a chemically amplified resist composition exhibiting excellent resolution and exposure margin. Since it becomes an acid generator, it is preferable.

P ^{25 to} P ²⁷ in the formulas (IVa) to (IVc) represent a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a cyclic hydrocarbon group having 3 to 12 carbon atoms. , L, m and n each independently represent an integer of 0 to 5. R represents an alkyl group having 1 to 6 carbon atoms.

（式（Ｖ）中、Ｘ、Ｙ、Ｑ¹、Ｑ²、Ｍは前記と同じ意味を表す。）
式（ＶIII）で示される化合物とを反応させることにより製造することができる。

（式（ＶIII）中、Ａ⁺は、前記と同じ意味を表し、ＬはＦ、Ｃｌ、Ｂｒ、Ｉ、ＢＦ₄、ＡｓＦ₆、ＳｂＦ₆、ＰＦ₆又はＣｌＯ₄を表す。） Examples of the method for producing the salt represented by the formula (I) include a salt represented by the formula (V),

(In the formula (V), X, Y, Q ¹ , Q ² and M have the same meaning as described above.)
It can be produced by reacting with a compound represented by the formula (VIII).

(In formula (VIII), A ⁺ represents the same meaning as described above, and L represents F, Cl, Br, I, BF ₄ , AsF ₆ , SbF ₆ , PF _6, or ClO _4. )

  In the reaction, for example, stirring is performed in an inert solvent such as acetonitrile, water, methanol, chloroform, and methylene chloride in a temperature range of about 0 ° C to 150 ° C, preferably in a temperature range of about 0 ° C to 100 ° C. And a method of reacting a salt represented by the formula (V) with a compound represented by the formula (VIII) to obtain a salt represented by the formula (I).

  The amount of the compound represented by the formula (VIII) is usually about 0.5 to 2 mol with respect to 1 mol of the salt represented by the formula (V). The salt represented by the formula (I) may be taken out by recrystallization or may be purified by washing with water.

（式（ＶI）中、Ｘ及びＹは、前記と同じ意味を表す。ＺはＣｌ、Ｂｒ又はＩを表す。）
式（ＶII）

（式（ＶII）中、Ｑ¹、Ｑ²およびＭは、前記と同じ意味を表す。）
で示されるカルボン酸とを反応させて、式（Ｖ）で示される塩を得る方法などが挙げられる。 Examples of the method for producing the salt represented by the formula (V) used for the production of the salt represented by the formula (I) include a compound represented by the formula (VI),

(In the formula (VI), X and Y represent the same meaning as described above. Z represents Cl, Br or I.)
Formula (VII)

(In formula (VII), Q ¹ , Q ² and M represent the same meaning as described above.)
And a method of obtaining a salt represented by the formula (V) by reacting with a carboxylic acid represented by formula (V).

  The reaction is usually carried out in a polar solvent such as acetone, acetonitrile, N, N-dimethylformamide and the like in a temperature range of about 0 ° C. to 150 ° C., preferably in a temperature range of about 20 ° C. to 120 ° C. Just do it. In the reaction, a base such as potassium carbonate is usually added as a base catalyst. Further, potassium iodide or the like may be added as a cocatalyst.

  The amount of the carboxylic acid represented by the formula (VII) used in the reaction is about 0.2 to 3 mol, preferably about 0.5 to 2 mol, relative to 1 mol of the compound represented by the formula (VI). is there.

（式（ＩＸ）中、Ｑ¹、Ｑ²およびＡ⁺は、前記と同じ意味を表す。）
式（ＶI）

（式（ＶI）中、Ｘ、ＹおよびＺは、前記と同じ意味を表す。）
で示される化合物とを反応させて、式（Ｖ）で示される塩を得る方法などが挙げられる。 Further, as another method for producing the salt represented by the formula (I), for example, a salt represented by the formula (IX),

(In formula (IX), Q ¹ , Q ² and A ⁺ represent the same meaning as described above.)
Formula (VI)

(In the formula (VI), X, Y and Z have the same meaning as described above.)
And a method of obtaining a salt represented by the formula (V) by reacting with a compound represented by formula (V).

  The reaction is usually carried out in a polar solvent such as acetone, acetonitrile, N, N-dimethylformamide and the like in a temperature range of about 0 ° C. to 150 ° C., preferably in a temperature range of about 20 ° C. to 120 ° C. Just do it. In the reaction, a base such as potassium carbonate is usually added as a base catalyst. Further, potassium iodide or the like may be added as a cocatalyst.

  The amount of the carboxylic acid represented by the formula (IX) in the reaction is about 0.2 to 3 mol, preferably about 0.5 to 2 mol, per 1 mol of the compound represented by the formula (VI). is there.

  The resin composition of the present invention is a resin composition containing a salt represented by the formula (I) and a resin, and the resin has an acid-labile group and is insoluble or hardly soluble in an alkaline aqueous solution. This resin is a resin that can be dissolved in an alkaline aqueous solution.

  The salt represented by the formula (I) is used as an acid generator, and the acid generated by exposure is cleaved by catalytically acting on a group in the resin which is unstable to the acid, to form a resin. Becomes soluble in an alkaline aqueous solution. Such a resin composition is suitable as a chemically amplified positive resist composition.

Examples of the acid labile group include a group having an alkyl ester in which the carbon atom adjacent to the oxygen atom is a quaternary carbon atom, a group having a carboxylic acid ester such as an alicyclic ester, and a carbon atom adjacent to the oxygen atom. And a group having a lactone ring which is a quaternary carbon atom.
Here, the quaternary carbon atom means a carbon atom bonded to a substituent other than a hydrogen atom and not bonded to hydrogen, and an acid labile group is a carbon at the α-position of an ether bond. It is preferred that the atom is a quaternary carbon atom bonded to three carbon atoms.

To illustrate a group having a carboxylic acid ester which is one of the acid labile group as R ester of -COOR, (-. The COO-C (CH ₃₎ referred in ₃ form a tert- butyl ester), tert -Alkyl ester in which the carbon atom adjacent to the oxygen atom represented by butyl ester is a quaternary carbon atom; methoxymethyl ester, ethoxymethyl ester, 1-ethoxyethyl ester, 1-isobutoxyethyl ester, 1-isopropoxyethyl Ester, 1-ethoxypropyl ester, 1- (2-methoxyethoxy) ethyl ester, 1- (2-acetoxyethoxy) ethyl ester, 1- [2- (1-adamantyloxy) ethoxy] ethyl ester, 1- [2 -(1-adamantanecarbonyloxy) ethoxy] ethyl ester Acetal-type esters such as tetrahydro-2-furyl ester and tetrahydro-2-pyranyl ester; isobornyl ester and 1-alkylcycloalkyl ester, 2-alkyl-2-adamantyl ester, 1- (1-adamantyl) -1- Examples thereof include alicyclic esters in which the carbon atom adjacent to the oxygen atom is a quaternary carbon atom, such as an alkylalkyl ester.

  Examples of the group having a carboxylic acid ester include a group having a (meth) acrylic acid ester, a norbornene carboxylic acid ester, a tricyclodecene carboxylic acid ester, and a tetracyclodecene carboxylic acid ester.

The resin of the resin composition of the present invention can be produced by addition polymerization of a monomer having an acid labile group and an olefinic double bond.
Such monomers include bulky groups such as alicyclic structures such as 2-alkyl-2-adamantyl groups and 1- (1-adamantyl) -1-alkylalkyl groups as acid labile groups. Monomers are preferred because the resolution of the resulting resist tends to be excellent.

  Specific examples of the monomer containing a bulky group include 2-alkyl-2-adamantyl (meth) acrylate, 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate, and 5-norbornene-2. -2-alkyl-2-adamantyl carboxylate, 1- (1-adamantyl) -1-alkylalkyl 5-norbornene-2-carboxylate, 2-alkyl-2-adamantyl α-chloroacrylate, α-chloroacrylic acid 1- (1-adamantyl) -1-alkylalkyl and the like.

  In particular, when 2-alkyl-2-adamantyl (meth) acrylate or 2-alkyl-2-adamantyl α-chloroacrylate is used as a monomer, it is preferable because the resolution of the resulting resist tends to be excellent.

  Specifically, as 2-alkyl-2-adamantyl (meth) acrylate, for example, 2-methyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-acrylate Examples thereof include adamantyl, 2-ethyl-2-adamantyl methacrylate, 2-n-butyl-2-adamantyl acrylate, and the like. Examples of α-chloroacrylic acid 2-alkyl-2-adamantyl include α-chloroacrylic acid. Examples include 2-methyl-2-adamantyl and 2-ethyl-2-adamantyl α-chloroacrylate.

  Among these, when 2-ethyl-2-adamantyl (meth) acrylate or 2-isopropyl-2-adamantyl (meth) acrylate is used, the resulting resist tends to have excellent sensitivity and heat resistance. preferable.

  (Meth) acrylic acid 2-alkyl-2-adamantyl can be usually produced by a reaction of 2-alkyl-2-adamantanol or a metal salt thereof with acrylic acid halide or methacrylic acid halide.

The resin used in the present invention may contain a structural unit derived from an acid-stable monomer in addition to a structural unit derived from a monomer having an acid-labile group. Here, the structure derived from an acid-stable monomer means a structure that is not cleaved by the salt (I) of the present invention.
Specifically, a structural unit derived from a monomer having a free carboxylic acid group such as acrylic acid or methacrylic acid, or a structural unit derived from an aliphatic unsaturated dicarboxylic anhydride such as maleic anhydride or itaconic anhydride , A structural unit derived from 2-norbornene, a structural unit derived from (meth) acrylonitrile, a carbon atom adjacent to the oxygen atom is a secondary carbon atom or an alkyl ester or 1-adamantyl ester of a tertiary carbon atom (meth) Structural units derived from acrylates, structural units derived from styrene monomers such as p- or m-hydroxystyrene, derived from (meth) acryloyloxy-γ-butyrolactone in which the lactone ring may be substituted with an alkyl group And a structural unit. In the 1-adamantyl ester, the carbon atom adjacent to the oxygen atom is a quaternary carbon atom. However, the 1-adamantyl ester is an acid-stable group, and a hydroxyl group or the like may be bonded to the 1-adamantyl ester.

  Specific examples of acid-stable monomers include 3-hydroxy-1-adamantyl (meth) acrylate, 3,5-dihydroxy-1-adamantyl (meth) acrylate, α- (meth) acryloyloxy-γ-butyrolactone, β- (meth) acryloyloxy-γ-butyrolactone, a monomer deriving the structural unit represented by the formula (a), a monomer deriving the structural unit represented by the formula (b), hydroxystyrene, norbornene, etc. Examples thereof include an alicyclic compound having a bond, an aliphatic unsaturated dicarboxylic acid anhydride such as maleic anhydride, and itaconic anhydride.

  Among these, in particular, structural units derived from styrene monomers such as p- or m-hydroxystyrene, structural units derived from 3-hydroxy-1-adamantyl (meth) acrylate, (meth) acrylic acid 3,5 A resist obtained from a resin containing any one of a structural unit derived from -dihydroxy-1-adamantyl, a structural unit represented by formula (a), and a structural unit represented by formula (b) has the following characteristics: This is preferable because the resolution of the image tends to be improved.

（式中、Ｒ¹及びＲ²は、互いに独立に、水素原子又はメチル基を表し、Ｒ³及びＲ⁴は、互いに独立に水素原子、メチル基、トリフルオロメチル基又はハロゲン原子を表し、ｉ及びｊは、１〜３の整数を表す。ｉが２または３のときには、Ｒ³は互いに異なる基であってもよく、ｊが２または３のときには、Ｒ⁴は互いに異なる基であってもよい。）

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group; R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group, a trifluoromethyl group, or a halogen atom; And j represents an integer of 1 to 3. When i is 2 or 3, R ³ may be a different group, and when j is 2 or 3, R ⁴ may be a different group. Good.)

  Monomers such as (meth) acrylic acid 3-hydroxy-1-adamantyl and (meth) acrylic acid 3,5-dihydroxy-1-adamantyl are commercially available. For example, the corresponding hydroxyadamantane is converted to (meth) acrylic acid or It can also be produced by reacting with the halide.

  In addition, a monomer such as (meth) acryloyloxy-γ-butyrolactone is obtained by reacting α- or β-bromo-γ-butyrolactone, in which the lactone ring may be substituted with an alkyl group, with acrylic acid or methacrylic acid, or lactone It can be produced by reacting an α- or β-hydroxy-γ-butyrolactone whose ring may be substituted with an alkyl group with an acrylic acid halide or a methacrylic acid halide.

  Specific examples of the monomer that gives the structural unit represented by formula (a) or formula (b) include (meth) acrylic acid esters of alicyclic lactones having a hydroxyl group such as the following, and mixtures thereof. It is done. These esters can be produced, for example, by reacting a corresponding alicyclic lactone having a hydroxyl group with (meth) acrylic acids (see, for example, JP-A No. 2000-26446).

  Here, as (meth) acryloyloxy-γ-butyrolactone, for example, α-acryloyloxy-γ-butyrolactone, α-methacryloyloxy-γ-butyrolactone, α-acryloyloxy-β, β-dimethyl-γ-butyrolactone, α- Methacryloyloxy-β, β-dimethyl-γ-butyrolactone, α-acryloyloxy-α-methyl-γ-butyrolactone, α-methacryloyloxy-α-methyl-γ-butyrolactone, β-acryloyloxy-γ-butyrolactone, β- Examples include methacryloyloxy-γ-butyrolactone, β-methacryloyloxy-α-methyl-γ-butyrolactone, and the like.

  In the case of KrF excimer laser exposure, sufficient transmittance can be obtained even if a structural unit derived from a styrene monomer such as p- or m-hydroxystyrene is used as the structural unit of the resin. Such a copolymer resin can be obtained by radically polymerizing the corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and styrene and then deacetylating with an acid.

  Moreover, since the resin containing a structural unit derived from 2-norbornene has an alicyclic skeleton directly in the main chain, it has a sturdy structure and exhibits excellent dry etching resistance. The structural unit derived from 2-norbornene can be introduced into the main chain by radical polymerization using, in addition to the corresponding 2-norbornene, an aliphatic unsaturated dicarboxylic anhydride such as maleic anhydride or itaconic anhydride. Therefore, the one formed by opening the double bond of the norbornene structure can be represented by the formula (c), and the one formed by opening the double bond of maleic anhydride and itaconic anhydride is respectively It can represent with Formula (d) and Formula (e).

Here, R ⁵ and R ⁶ in formula (c) are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a carboxyl group, a cyano group, or —COOU (U is an alcohol residue). Or R ⁵ and R ⁶ are bonded to each other to represent a carboxylic anhydride residue represented by —C (═O) OC (═O) —.
When R ⁵ and R ⁶ are a group —COOU, the carboxyl group is an ester group, and the alcohol residue corresponding to U has, for example, about 1 to 8 carbon atoms that may be substituted. And an alkyl group, a 2-oxooxolan-3- or -4-yl group. Here, in the alkyl group, a hydroxyl group, an alicyclic hydrocarbon residue, or the like may be bonded as a substituent.
Specific examples when R ⁵ and R ⁶ are alkyl groups include a methyl group, an ethyl group, and a propyl group. Specific examples of the alkyl group to which a hydroxyl group is bonded include a hydroxymethyl group and 2-hydroxyethyl group. Group and the like.

As described above, specific examples of the norbornene structure represented by the formula (c), which is a monomer that gives a stable structural unit to an acid, include the following compounds.
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, if U of R ⁵ and R ⁶ —COOU in the formula (c) is an acid labile group such as an alicyclic ester in which the carbon atom adjacent to the oxygen atom is a quaternary carbon atom, Although it has a norbornene structure, it 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, and 5-norbornene. 2-carboxylate 1-methylcyclohexyl, 5-norbornene-2-carboxylic acid 2-methyl-2-adamantyl, 5-norbornene-2-carboxylic acid 2-ethyl-2-adamantyl, 5-norbornene-2-carboxylic 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-adama) Chill) -1-methylethyl and the like.

  The resin used in the resin composition of the present invention varies depending on the type of radiation used for patterning exposure and the type of acid labile group, but is usually derived from a monomer having an acid labile group in the resin. The content of the structural unit is adjusted to a range of 10 to 80 mol%.

  And as a structural unit derived from a monomer having an acid labile group, in particular, 2-alkyl-2-adamantyl (meth) acrylate and 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate When the derived structural unit is included, if the structural unit is 15 mol% or more of the total structural units constituting the resin, the resin has a rugged structure because of the alicyclic group, and the resist has a dry etching resistance. Is advantageous.

  In addition, when using an alicyclic compound having an olefinic double bond in the molecule and an aliphatic unsaturated dicarboxylic acid anhydride as monomers, these tend to be difficult to undergo addition polymerization. These are preferably used in excess.

  Further, as the monomer used, monomers having the same olefinic double bond but different acid labile groups may be used in combination, or monomers having the same acid labile group but different olefinic double bonds may be used. You may use together, and you may use together the monomer from which the combination of an acid labile group and an olefinic double bond differs.

  When the resin composition of the present invention is used as a chemically amplified resist composition, a basic compound, preferably a basic nitrogen-containing organic compound, particularly preferably an amine or ammonium salt is contained. By adding a basic compound as a quencher, it is possible to improve the performance degradation due to the deactivation of the acid accompanying the holding after exposure. Specific examples of the basic compound used for the quencher include those represented by the following formulas.

In the formula, R ¹¹ , R ¹² and R ¹⁷ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has about 6 to 10 carbon atoms. Of carbon atoms. Further, at least one hydrogen atom on the alkyl group, cycloalkyl group or aryl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. Good. At least one hydrogen atom on the amino group may be independently substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹³ and R ¹⁴ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an alkoxy group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. The alkoxy group preferably has 1 to 6 carbon atoms. Alternatively, R ¹³ and R ¹⁴ may be bonded to form an aromatic ring.
Further, at least one hydrogen atom on the alkyl group, cycloalkyl group, aryl group, or alkoxy group is independently a hydroxyl group, an amino group, or an alkoxy group having about 1 to 6 carbon atoms. May be substituted. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁵ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group or a nitro group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. The alkoxy group preferably has 1 to 6 carbon atoms.
Further, at least one hydrogen atom on the alkyl group, cycloalkyl group, aryl group, or alkoxy group is independently a hydroxyl group, an amino group, or an alkoxy group having about 1 to 6 carbon atoms. May be substituted. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁶ represents an alkyl group or a cycloalkyl group. The alkyl group preferably has about 1 to 6 carbon atoms, and the cycloalkyl group preferably has about 5 to 10 carbon atoms. Furthermore, at least one hydrogen atom on the alkyl group or cycloalkyl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁸ , R ¹⁹ and R ²⁰ each independently represents an alkyl group, a cycloalkyl group or an aryl group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. Has about carbon atoms. Furthermore, at least one hydrogen atom on the alkyl group, cycloalkyl group or aryl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. . At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

W represents an alkylene group, a carbonyl group, an imino group, a sulfide group or a disulfide group. The alkylene group preferably has about 2 to 6 carbon atoms.
Further, in R ^{11 to} R ²⁰ , any of those that can take both a linear structure and a branched structure may be used.

  Specific examples of such compounds include hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, 1- or 2-naphthylamine, and 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, tributylamine , 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, pyridine, -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'-dipicolylamine, 3,3'-dipicolylamine, tetramethylammonium hydroxide Tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra-n-hexylammonium hydroxide, tetra-n- Examples include octylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-trifluoromethylphenyltrimethylammonium hydroxide, (2-hydroxyethyl) trimethylammonium hydroxide (common name: choline), and the like.

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

The resin composition of the present invention preferably contains about 80 to 99.9% by weight of resin and about 0.1 to 20% by weight of acid generator based on the total solid content.
Further, when a basic compound that is a quencher is used as the chemically amplified resist composition, it is preferably contained in a range of about 0.01 to 1% by weight based on the total solid content of the resist composition.
The resist composition can further contain small amounts of various additives such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, and dyes as necessary.

  The resist composition of the present invention is usually used as a resist solution composition in a state in which each of the above components is dissolved in a solvent, and is usually used in industrial processes such as spin coating on a substrate such as a silicon wafer. Applied by. The solvent used here may be any solvent that dissolves each component, has an appropriate drying rate, and gives a uniform and smooth coating film after the solvent evaporates, and is usually used industrially in this field. A solvent can be used.

  For example, glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, glycol ethers such as propylene glycol monomethyl ether, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate And ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone, and cyclic esters such as γ-butyrolactone. These solvents can be used alone or in combination of two or more.

  The resist film coated and dried on the substrate is subjected to an exposure process for patterning, followed by a heat treatment for promoting a deprotecting group reaction, and then developed with an alkali developer. The alkaline developer used here may be various alkaline aqueous solutions used in this field, but generally an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline) is used. Often used.

EXAMPLES Next, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited at all by these Examples.
In Examples and Comparative Examples, “%” and “part” representing content or use amount are based on weight unless otherwise specified. The weight average molecular weight is a value obtained by gel permeation chromatography (HLC-8120GPC type manufactured by Tosoh Corporation, column is TSKgel Multipore HXL-M3, solvent is tetrahydrofuran) using polystyrene as a standard product.
Moreover, the structure of the compound was confirmed by NMR (JEOL EX-270 type) and mass spectrometry (LC is Agilent 1100 type, and MASS is Agilent LC / MSD type or LC / MSD TOF type).

Intermediate Synthesis Example 1 Synthesis of Intermediate (B4) 14.2% triphenylsulfonium chloride aqueous solution (573.7 parts) was added with 18.0% difluorosulfoacetate sodium salt aqueous solution (300.0 parts), and about 20 at 25 ° C. Stir for hours. The precipitated white solid was separated by filtration, washed with 100 parts of ion exchange water, and dried to obtain 88.4 parts of triphenylsulfonium hydroxycarbonyldifluoromethanesulfonate (B4).

¹ H-NMR (dimethyl sulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 7.77-7.88 (m, 15H); 13.90 (br, 1H)
MS (ESI (+) Spectrum): M + 263.2 (C ₁₈ H ₁₅ S ⁺ = 263.09)
MS (ESI (-) Spectrum) : M- 175.0 (C 2 HF 2 O 5 S - = 174.95)

Synthesis of Acid Generator 1: Synthesis of Acid Generator (B1) 8.8 parts of (B4) obtained by the same synthesis method as above were dissolved in 70.2 parts of N, N′-dimethylformamide, and potassium carbonate 2.8 parts and 0.8 parts of potassium iodide were added and stirred at 50 ° C. for about 1 hour. Thereafter, the mixture was cooled to 40 ° C., a solution prepared by dissolving 4.9 parts of 2-methyl-2-adamantyl 2-chloroacetate (B5) in 10 parts of N, N′-dimethylformamide was added dropwise, and reacted at 40 ° C. for 44 hours. . After the reaction, the mixture was cooled, 98 parts of chloroform and 98 parts of ion-exchanged water were added, stirred, allowed to stand, and then separated. The aqueous layer was extracted twice with 98 parts of chloroform, and all the organic layers were combined and washed repeatedly with 98 parts of ion-exchanged water until the aqueous layer became neutral. The organic layer was concentrated, 77 parts of ethyl acetate was added and stirred, and the precipitated white solid was filtered off and dried to obtain 7 of triphenylsulfonium 2-methyl-2-adamantyloxycarbonylmethoxycarbonyldifluoromethanesulfonate (B1). .8 parts were obtained.

¹ H-NMR (dimethyl sulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 1.48-1.99 (m, 15H); 2.19 (s, 2H); 4.80 (s , 2H); 7.74-7.89 (m, 15H)
MS (ESI (+) Spectrum): M + 263.0 (C ₁₈ H ₁₅ S ⁺ = 263.09)
MS (ESI (−) Spectrum): M-381.0 (C ₁₅ H ₁₉ F ₂ O ₇ S ⁻ = 381.08)

Acid generator synthesis example 2: Synthesis of acid generator (B2) 9.5 parts of (B4) obtained by the same synthesis method as above were dissolved in 47.6 parts of N, N'-dimethylformamide, and potassium carbonate was added. 3.0 parts and 0.9 parts of potassium iodide were added and stirred at 50 ° C. for about 1 hour. Thereafter, the mixture was cooled to 40 ° C., and 5.0 parts of chloroacetic acid hexahydro-2-oxo-3,5-methano-2H-cyclopenta [b] furan-6-yl (B6) was added to 40 parts of N, N′-dimethylformamide. The dissolved solution was added dropwise and reacted at 40 ° C. for 23 hours. After the reaction, the reaction mixture was cooled, 106 parts of chloroform and 106 parts of ion-exchanged water were added, stirred, allowed to stand, and then separated. The aqueous layer was extracted twice with 106 parts of chloroform, and all the organic layers were combined and washed repeatedly with 106 parts of ion-exchanged water until the aqueous layer became neutral. After adding 3.5 parts of activated carbon to the organic layer and stirring, it was filtered. The filtrate was concentrated, 38 parts of ethyl acetate was added and stirred, and then the supernatant was removed. After adding 38 parts of tert-butyl methyl ether to the residue and stirring, the supernatant was removed. The residue was dissolved in chloroform and concentrated to give triphenylsulfonium hexahydro-2-oxo-3,5-methano-2H-cyclopenta [b] furan-6-yloxycarbonylmethoxycarbonyldifluoromethanesulfo as an amber oil. 4.3 parts of Nart (B2) were obtained.

¹ H-NMR (dimethyl sulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 1.59 (t, 2H, J = 11.5 Hz); 1.87-2.06 (m, 2H) 2.41-2.53 (m, 2H); 3.17 (t, 1H, 4.6 Hz); 4.53-4.56 (m, 2H); 4.89 (s, 2H); 7 .74-7.89 (m, 15H)
MS (ESI (+) Spectrum): M + 263.0 (C ₁₈ H ₁₅ S ⁺ = 263.09)
MS (ESI (−) Spectrum): M− 369.0 (C ₁₂ H ₁₁ F ₂ O ₉ S ⁻ = 369.01)

Acid generator synthesis example 3: Synthesis of acid generator (B3) 9.0 parts of (B4) obtained by the same synthesis method as above were dissolved in 45.2 parts of N, N'-dimethylformamide, and potassium carbonate was added. 2.9 parts and 0.9 parts of potassium iodide were added and stirred at 50 ° C. for about 1 hour. Thereafter, the mixture was cooled to 40 ° C., a solution prepared by dissolving 5.0 parts of 4-oxo-1-adamantyl 2-chloroacetate (B7) in 10 parts of N, N′-dimethylformamide was added dropwise, and reacted at 40 ° C. for 32 hours. . After the reaction, the reaction mixture was cooled, 73 parts of chloroform and 73 parts of ion-exchanged water were added, stirred, allowed to stand, and then separated. The aqueous layer was extracted twice with 73 parts of chloroform, all the organic layers were combined, and washing with water was repeated until the aqueous layer became neutral with 73 parts of ion-exchanged water. After adding 3.1 parts of activated carbon to the organic layer and stirring, it was filtered. The filtrate was concentrated, and 84 parts of ethyl acetate was added and stirred, followed by filtration. The filtrate was concentrated, 60 parts of tert-butyl methyl ether was added and stirred, and the precipitated pale yellow solid was filtered off and dried to obtain triphenylsulfonium 4-oxo-1-adamantyloxycarbonylmethoxycarbonyldifluoromethanesulfonate ( 4.9 parts of B3) were obtained.

¹ H-NMR (dimethyl sulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 1.81 (d, 2H, J = 12.7 Hz); 1.97 (d, 2H, J = 12. 2.23-2.35 (m, 7H); 2.50 (s, 2H); 4.77 (s, 2H); 7.74-7.89 (m, 15H)
MS (ESI (+) Spectrum): M + 263.1 (C ₁₈ H ₁₅ S ⁺ = 263.09)
MS (ESI (−) Spectrum): M-381.1 (C ₁₄ H ₁₅ F ₂ O ₈ S ⁻ = 381.05)

Synthesis Example 1 of Comparative Control Acid Generator 1: Synthesis of triphenylsulfonium 1-adamantylmethoxycarbonyldifluoromethanesulfonate (acid generator C1) (1) 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 250 parts of ion-exchanged water Then, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The 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 sodium difluorosulfoacetate (containing inorganic salt, purity 62.6%).
(2) 39.4 parts (purity 63.5%) of difluorosulfoacetate sodium salt obtained by the same synthesis method as in (1) above, 21.0 parts of 1-adamantane methanol, and 200 parts of dichloroethane were charged, and p- Toluenesulfonic acid (p-TsOH) 24.0 parts was added, and the mixture was heated to reflux for 7 hours. Thereafter, the mixture was concentrated to distill off dichloroethane, 250 parts of tert-butyl methyl ether was added, and the mixture was stirred and then filtered. To the filtration residue, 250 parts of acetonitrile was added, stirred and filtered, and the filtrate was concentrated to obtain 32.8 parts of difluorosulfoacetic acid-1-adamantylmethyl ester sodium salt.

(3) 32.8 parts of difluorosulfoacetic acid-1-adamantylmethyl ester sodium salt obtained in (2) above was charged and dissolved in 100 parts of ion-exchanged water. To this solution, 28.3 parts of triphenylsulfonium chloride and 140 parts of methanol were added. The mixture was stirred at room temperature for 15 hours, concentrated and extracted twice with 200 parts of chloroform. All the organic layers were combined and washed with ion-exchanged water, and the resulting organic layer was concentrated. The concentrated solution was added with 300 parts of tert-butyl methyl ether, stirred, filtered, and dried under reduced pressure to obtain 39.7 parts of triphenylsulfonium 1-adamantylmethoxycarbonyldifluoromethanesulfonate (C1) as white crystals.

¹ H-NMR (dimethyl sulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 1.52 (d, 6H); 1.63 (dd, 6H); 1.93 (s, 3H); 3.81 (s, 2H); 7.76-7.90 (m, 15H)
MS (ESI (+) Spectrum): M + 263.2 (C ₁₈ H ₁₅ S ⁺ = 263.09)
MS (ESI (−) Spectrum): M− 323.0 (C ₁₃ H ₁₇ F ₂ O ₅ S ⁻ = 323.08)

Resin Synthesis Example 1: Synthesis of Resin A1 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate, and α-methacryloyloxy-γ-butyrolactone were mixed with 5: 2.5: 2.5. The methyl isobutyl ketone was added 2 times by weight with respect to the total monomer to prepare a solution. Thereto, 2 mol% of azobisisobutyronitrile as an initiator was added with respect to the total amount of monomers and heated at 80 ° C. for about 8 hours. Thereafter, the operation of pouring the reaction solution into a large amount of heptane and precipitating was performed three times for purification. As a result, a copolymer having a weight average molecular weight of about 9200 was obtained. This copolymer has each structural unit shown by following Formula, and this is set as resin A1.

Next, in addition to the resin (A1) obtained in the above resin synthesis example, a resist composition was prepared and evaluated using the raw materials shown below.
The amount of each acid generator introduced was adjusted to be an equimolar amount.

酸発生剤Ｂ２：

酸発生剤Ｂ３：

酸発生剤Ｃ１：

＜クエンチャー＞
クエンチャーＱ１：２，６−ジイソプロピルアニリン
＜溶剤＞
溶剤Ｙ１：
プロピレングリコールモノメチルエーテルアセテート ５１．５部
２−ヘプタノン ３５．０部
γ−ブチロラクトン ３．５部 <Acid generator>
Acid generator B1:

Acid generator B2:

Acid generator B3:

Acid generator C1:

<Quencher>
Quencher Q1: 2,6-diisopropylaniline <solvent>
Solvent Y1:
Propylene glycol monomethyl ether acetate 51.5 parts 2-heptanone 35.0 parts γ-butyrolactone 3.5 parts

Examples 1 to 3 and Comparative Example 1
The following components were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist solution.

Resin (type and amount are listed in Table 1)
Acid generator (type and amount are listed in Table 1)
Quencher (type and amount are listed in Table 1)
Solvent (type is listed in Table 1)

By applying “ARC95” which is a composition for organic antireflection film manufactured by Nissan Chemical Industries, Ltd. to a silicon wafer and baking at 205 ° C. for 60 seconds, an organic antireflection film having a thickness of 295 mm is formed. Next, the resist solution was spin-coated thereon so that the film thickness after drying was 0.25 μm. After application of the resist solution, pre-baking was performed for 60 seconds on a proximity hot plate at the temperature indicated in the column “PB” in Table 1. Each wafer on which the resist film was formed in this manner was subjected to a line-by-step exposure using an ArF excimer stepper (“FPA-5000AS3” manufactured by Canon Inc., NA = 0.75, 2/3 Annular). The andspace pattern was exposed.
After exposure, post-exposure baking was performed on the hot plate at the temperature indicated in the column “PEB” in Table 1 for 60 seconds, and further, development was performed for 15 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution. .
The line and space pattern after development on the organic antireflection film substrate was observed with a scanning electron microscope, or the line width of the line was measured. The results are shown in Table 2.

Effective sensitivity: The exposure amount at which the line width of a 100 nm line and space is exactly 100 nm is displayed.
Resolution: Displayed with the minimum dimension of the line and space pattern separated by the exposure amount of effective sensitivity.
Exposure margin: The amount of change in line width with respect to the change in exposure amount in the vicinity of effective sensitivity (exposure amount range in which the line width is 115 nm to 85 nm) is displayed. The smaller this value, the better the exposure margin.

[Table 1]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example No. Resin Acid generator Quencher Solvent PB / PEB
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example 1 A1 / 10 part B1 / 0.2857 part Q1 / 0.0325 part Y1 125 ℃ / 125 ℃
Example 2 A1 / 10 part B2 / 0.2804 part Q1 / 0.0325 part Y1 125 ° C / 125 ° C
Example 3 A1 / 10 part B3 / 0.2857 part Q1 / 0.0325 part Y1 125 ° C / 125 ° C
───────────────────────────────────────
Comparative Example 1 A1 / 10 part C1 / 0.26 part Q1 / 0.0325 part Y1 125 ℃ / 125 ℃
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[Table 2]
━━━━━━━━━━━━━━━━━━━━━━━━━
Example No. Sensitivity Resolution Exposure margin
(mJ / cm ² ) (nm) (nm / mJ)
━━━━━━━━━━━━━━━━━━━━━━━━━
Example 1 27 90 6.1
Example 2 37 85-90 4.1
Example 3 32 85 3.9
────────────────────────
Comparative Example 1 27 90 6.9
━━━━━━━━━━━━━━━━━━━━━━━━━

  Compared with the comparative example 1 using the conventional acid generator, the exposure margin was improved in Example 1, and the resolution and the exposure margin were improved in Examples 2 and 3.

  The salt of the present invention is suitably used as an acid generator for a chemically amplified positive resist composition that gives excellent resolution and exposure margin, and is particularly suitable for excimer laser lithography such as ArF and KrF and ArF immersion exposure lithography. It can be used as an acid generator for a suitable chemically amplified positive resist composition.

Claims (13)

A salt represented by the formula (I):

(In the formula (I), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and X is a C 1-12 divalent group, linear or branched. Y represents a hydrocarbon group containing an adamantane skeleton or a norbornane skeleton having 7 to 30 carbon atoms, and A ⁺ represents a formula (IIIa), a formula (IIIb) or a formula (Represents a cation represented by any of (IIIc).)

(In the formula (IIIa) ~ (IIIc), the P ²² to P ²⁴ are independently a linear or branched number 3-30 carbon other than or a phenyl group represents an alkyl group having 1 to 20 carbon atoms Represents a cyclic hydrocarbon group, and when P ^{22 to} P ²⁴ are alkyl groups, one or more of a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or a cyclic hydrocarbon group having 3 to 12 carbon atoms is substituted. substituted may contain as a base, if P ²² to P ²⁴ is a cyclic hydrocarbon group, a hydroxyl group, one or more alkyl or alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms P ^{25 to} P ^{30 each} represents a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a cyclic hydrocarbon group having 3 to 12 carbon atoms; , M, n, o, p and q each independently represent an integer of 0 to 5.)
The salt according to claim 1, wherein Q ¹ and Q ² are each independently a fluorine atom or —CF ₃ . Y is a hydrocarbon group containing an adamantane skeleton or norbornane skeleton having 7-20 carbon atoms, the carbon atoms contained in the hydrocarbon group for Y may have its partially is replaced by an oxygen atom or a carbonyl group 1 Valence residues (all skeletons are alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, perfluoroalkyl groups having 1 to 4 carbon atoms, hydroxyalkyl groups having 1 to 6 carbon atoms, hydroxyl groups, and cyano) The salt according to claim 1 or 2, wherein one or more groups may be contained as a substituent.
The salt according to any one of claims 1 to 3, wherein X is a methylene group , an ethylene group , a trimethylene group or a tetramethylene group . The salt according to any one of claims 1 to 4 , wherein the salt represented by the formula (I) is a salt represented by the formula (IVa), the formula (IVb) or the formula (IVc).

(P ²⁵ to P ²⁷ in formula (IVa) ~ (IVc) is a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, a cyclic hydrocarbon group having 3 to 12 alkoxy group or a carbon number of 1 to 12 carbon atoms And l, m and n each independently represents an integer of 0 to 5. R represents an alkyl group having 1 to 6 carbon atoms.) An acid generator comprising the salt according to any one of claims 1 to 5 as an active ingredient. A salt represented by the formula (V):

(In formula (V), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and X is a C 1-12 divalent group, linear or branched. And Y represents a hydrocarbon group containing an adamantane skeleton or a norbornane skeleton having 7 to 30 carbon atoms, and M represents Li, Na, K or Ag.)
A compound of formula (VI);

(In the formula (VI), X represents a divalent group having 1 to 12 carbon atoms and represents a linear or branched chain hydrocarbon group, and Y represents an optionally substituted adamantane having 7 to 30 carbon atoms. Represents a hydrocarbon group containing a skeleton or a norbornane skeleton, Z represents Cl, Br or I.) Formula (VII)

(In formula (VII), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and M represents Li, Na, K, or Ag.)
And a carboxylic acid represented by the formula (V)

(In formula (V), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and X is a C 1-12 divalent group, linear or branched. And Y represents a hydrocarbon group containing an adamantane skeleton or a norbornane skeleton having 7 to 30 carbon atoms, and M represents Li, Na, K or Ag.)
The manufacturing method of the salt shown by these.
Formula (V)

(In formula (V), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and X is a C 1-12 divalent group, linear or branched. And Y represents a hydrocarbon group containing an adamantane skeleton or a norbornane skeleton having 7 to 30 carbon atoms, and M represents Li, Na, K or Ag.)
A method for producing a salt represented by the formula (I), comprising reacting a salt represented by the formula (VIII) with a compound represented by the formula (VIII):

(In Formula (VIII), A ⁺ represents a cation represented by any one of Formula (IIIa), Formula (IIIb), or Formula (IIIc), and L represents F, Cl, Br, I, BF ₄ , AsF _6. , SbF ₆ , PF ₆ or ClO ₄ .

(In the formula (IIIa) ~ (IIIc), the P ²² to P ²⁴ are independently a linear or branched number 3-30 carbon other than or a phenyl group represents an alkyl group having 1 to 20 carbon atoms Represents a cyclic hydrocarbon group, and when P ^{22 to} P ²⁴ are alkyl groups, one or more of a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or a cyclic hydrocarbon group having 3 to 12 carbon atoms is substituted. substituted may contain as a base, if P ²² to P ²⁴ is a cyclic hydrocarbon group, a hydroxyl group, one or more alkyl or alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms P ^{25 to} P ^{30 each} represents a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a cyclic hydrocarbon group having 3 to 12 carbon atoms; , M, n, o, p and q each independently represent an integer of 0 to 5.)

(In the formula (I), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and X is a C 1-12 divalent group, linear or branched. Y represents a hydrocarbon group containing an adamantane skeleton or a norbornane skeleton having 7 to 30 carbon atoms, and A ⁺ represents a formula (IIIa), a formula (IIIb) or a formula (Represents a cation represented by any of (IIIc).)
A salt of formula (IX)

(In the formula (IX), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and A ⁺ is represented by the formula (IIIa), the formula (IIIb) or the formula (IIIc). Represents a cation represented by any of them.)
A method for producing a salt represented by the formula (I), which comprises reacting a compound represented by the formula (VI).

(In the formula (VI), X is a divalent group having 1 to 12 carbon atoms and represents a linear or branched chain hydrocarbon group, and Y is an optionally substituted adamantane having 7 to 30 carbon atoms. Represents a hydrocarbon group containing a skeleton or a norbornane skeleton, Z represents Cl, Br or I.)

(In the formula (IIIa) ~ (IIIc), the P ²² to P ²⁴ are independently a linear or branched number 3-30 carbon other than or a phenyl group represents an alkyl group having 1 to 20 carbon atoms Represents a cyclic hydrocarbon group, and when P ^{22 to} P ²⁴ are alkyl groups, one or more of a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or a cyclic hydrocarbon group having 3 to 12 carbon atoms is substituted. substituted may contain as a base, if P ²² to P ²⁴ is a cyclic hydrocarbon group, a hydroxyl group, one or more alkyl or alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms P ^{25 to} P ^{30 each} represents a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a cyclic hydrocarbon group having 3 to 12 carbon atoms; , M, n, o, p and q each independently represent an integer of 0 to 5.)

(In the formula (I), Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and X is a C 1-12 divalent group, linear or branched. Y represents a hydrocarbon group containing an adamantane skeleton or a norbornane skeleton having 7 to 30 carbon atoms, and A ⁺ represents a formula (IIIa), a formula (IIIb) or a formula (Represents a cation represented by any of (IIIc).)
A resin composition comprising the acid generator according to claim 6 and a resin, wherein the resin has an acid-labile group, is a resin insoluble or hardly soluble in an alkaline aqueous solution, and acts with an acid. A resin composition, wherein the resin is a resin that can be dissolved in an alkaline aqueous solution. Claim 1 1 resin composition, wherein the resin comprising structural units resin derived from a monomer having a group unstable to bulky groups and acid. Claim 1 1 or 1 2 Resin composition according and a basic compound and a chemically amplified resist composition characterized by containing.