JP6095954B2 - Salt, resist composition and method for producing resist pattern - Google Patents

Description

  The present invention relates to a salt for an acid generator useful for a resist composition used for microfabrication of a semiconductor, a resist composition, and a method for producing a resist pattern.

  For example, Patent Document 1 describes a resist composition containing a salt represented by the following as a salt for an acid generator.

US Patent Application Publication No. 2011/0117495

  Conventional resist compositions containing the above-described acid generators may not always have sufficient pattern collapse resistance (PCM) of the resulting resist pattern.

The present invention includes the following inventions.
[1] 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.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, a methylene group constituting the saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group, in L ¹ The hydrogen atom contained in the saturated hydrocarbon group may be replaced with a fluorine atom.
L ² represents a single bond or a divalent saturated hydrocarbon group having 1 to 16 carbon atoms, and the methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ³ represents an oxygen atom, a methylene group or —CO—CH ₂ —.
Ring ^{W 1} represents an aromatic ring having 6 to 18 carbon atoms.
Ring W ² represents an aliphatic ring having 4 to 18 carbon atoms, a methylene group constituting the aliphatic ring may be replaced by an oxygen atom or a carbonyl group. However, at least one of the methylene groups contained in the aliphatic ring is replaced with a carbonyl group.
R ¹ represents a hydroxy group or an alkyl group having 1 to 6 carbon atoms.
R ² represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxycarbonyl group having 1 to 6 carbon atoms.
s represents the integer of 0-2. When s is 2, a plurality of R ¹ may be the same as or different from each other.
t represents an integer of 0-2. When t is 2, a plurality of R ² may be the same as or different from each other.
Z ⁺ represents an organic counter ion. ]

［式（ｂＬ１−１）中、
Ｌ^ｂ２は、単結合又は炭素数１〜１５の２価の飽和炭化水素基を表す。＊はＣ（Ｑ^１）（Ｑ^２）との結合手を表す。］ [2] The salt according to [1], wherein L ¹ is a group represented by the formula (bL1-1).

[In the formula (bL1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms. * Represents a bond with C (Q ¹ ) (Q ² ). ]

［式（ｂＬ２−１）中、
Ｌ^ｂ１３及びＬ^ｂ１４は、それぞれ独立に、単結合又は炭素数１〜１４の２価の飽和炭化水素基を表す。但しＬ^ｂ１３及びＬ^ｂ１４の合計炭素数の上限は１４である。＊は環Ｗ^１との結合手を表す。］ [3] The salt according to [1] or [2] above, wherein L ³ -L ² is a group represented by the formula (bL2-1).

[In the formula (bL2-1),
L ^b13 and L ^b14 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b13 and L ^b14 is 14. * Represents a bond with ring W ¹ . ]

[4] The salt according to any one of [1] to [3], wherein Z ⁺ is an arylsulfonium cation.
[5] An acid generator containing the salt according to any one of [1] to [4].
[6] The acid generator according to [5] above and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution. A resist composition that is a soluble resin.
[7] The resist composition according to [6], further containing a basic compound.

[8] (1) A step of applying the resist composition according to [6] or [7] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including:

  If a resist composition containing the salt of the present invention as an acid generator is used, a resist pattern having excellent pattern collapse resistance (PCM) can be produced.

<Salt represented by formula (I)>
The salt of the present invention is represented by the formula (I). (Hereinafter sometimes referred to as “salt (I)”)

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, a methylene group constituting the saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group, in L ¹ The hydrogen atom contained in the saturated hydrocarbon group may be replaced with a fluorine atom.
L ² represents a single bond or a divalent saturated hydrocarbon group having 1 to 16 carbon atoms, and the methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ³ represents an oxygen atom, a methylene group or —CO—CH ₂ —.
Ring ^{W 1} represents an aromatic ring having 6 to 18 carbon atoms.
Ring W ¹ represents an aliphatic ring having 4 to 18 carbon atoms, and the methylene group constituting the aliphatic ring may be replaced with an oxygen atom or a carbonyl group. However, at least one of the methylene groups contained in the aliphatic ring is replaced with a carbonyl group.
R ¹ represents a hydroxy group or an alkyl group having 1 to 6 carbon atoms.
R ² represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxycarbonyl group having 1 to 6 carbon atoms.
s represents the integer of 0-2. When s is 2, a plurality of R ¹ may be the same as or different from each other.
t represents an integer of 0-2. When t is 2, a plurality of R ² may be the same as or different from each other.
Z ⁺ represents an organic counter ion. ]

In the following description, the salt (I) having a negative charge obtained by removing the organic cation represented by Z ⁺ having a positive charge may be referred to as a “sulfonate anion”.
Examples of the C 1-6 perfluoroalkyl group represented by Q ¹ and Q ² include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluoro sec-butyl group, A perfluoro tert-butyl group, a perfluoropentyl group, a perfluorohexyl group and the like can be mentioned.
Q ¹ and Q ² are each independently preferably a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group having 1 to 17 carbon atoms in L ¹ and the saturated hydrocarbon group having 1 to 16 carbon atoms in L ² include a linear alkanediyl group, a branched alkanediyl group, a simple group. A cyclic or polycyclic divalent alicyclic hydrocarbon group may be mentioned, and a combination of two or more of these groups may be used.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1 , 6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group , Dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1, Linear alkanediyl groups such as 17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-diyl group;
An alkyl group (particularly an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group); For example, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl A branched alkanediyl group such as a 2-methylbutane-1,4-diyl group;
Cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,2-diyl group, 1-methylcyclohexane-1,2-diyl group, cyclohexane-1,4-diyl group, cyclo A monocyclic divalent alicyclic hydrocarbon group which is a cycloalkanediyl group such as an octane-1,2-diyl group or a cyclooctane-1,5-diyl group;
Norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,2-diyl group, adamantane-1,5-diyl group and adamantane-2,6 -Polycyclic bivalent alicyclic hydrocarbon groups, such as a diyl group, etc. are mentioned.

Examples of the group in which the methylene group in the divalent saturated hydrocarbon group having 1 to 17 carbon atoms represented by L ¹ is replaced by an oxygen atom or a carbonyl group include the following formulas (bL1-1) and (bL1- 2), Formula (bL1-3), Formula (bL1-4), Formula (bL1-5), Formula (bL1-6), and Formula (bL1-7) [Hereinafter, “Formula (bL1-1) to Formula ( bL1-7) ”. ] The group represented by either of these is mentioned. L ¹ is preferably a group represented by any one of formulas (bL1-1) to (bL1-5), more preferably a group represented by formulas (bL1-1) and (bL1-3) or It is group represented by a formula (bL1-5), More preferably, it is group represented by a formula (bL1-1). In addition, * represents the bond with the carbon atom of C (Q ¹ ) (Q ² ).

[In Formula (bL1-1)-Formula (bL1-7),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a C1-C13 divalent saturated hydrocarbon group. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b7 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 represents a single bond or a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^b10 represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
L ^b11 represents a single bond or a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b12 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b11 and L ^b12 is 14. ]

Examples of the divalent group represented by the formula (bL1-1) include the following.

Examples of the divalent group represented by the formula (bL1-2) include the following.

Examples of the divalent group represented by the formula (bL1-3) include the following.

Examples of the divalent group represented by the formula (bL1-4) include the following.

Examples of the divalent group represented by the formula (bL1-5) include the following.

Examples of the divalent group represented by the formula (bL1-6) include the following.

Examples of the divalent group represented by the formula (bL1-7) include the following.

Examples of the group represented by L ³ -L ² include the following formula (bL2-1), formula (bL2-2), and formula (bL2-3) [hereinafter, “formula (bL2-1) to formula ( bL2-3) ”. ] The group represented by either of these is mentioned. L ³ -L ² is preferably a group represented by either the formula (bL2-1) or the formula (bL2-3), and more preferably a group represented by the formula (bL2-1). Note that * represents a bond with ring W ¹ .

[In Formula (bL2-1) to Formula (bL2-3),
L ^b13 and L ^b14 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b13 and L ^b14 is 14.
L ^b15 and L ^b17 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms. However, the upper limit of the total carbon number of L ^b15 , L ^b16 and L ^b17 is 12.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b19 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^b18 and L ^b19 is 15. ]

Among these, L ³ -L ² is preferably a divalent group represented by the formula (bL2-1).
Examples of the divalent group represented by the formula (bL2-1) include the following.

Examples of the divalent group represented by the formula (bL2-2) include the following.

Examples of the divalent group represented by the formula (bL2-3) include the following.

Examples of the aromatic ring having 6 to 18 carbon atoms represented by ring W ¹ include an anthracene ring such as a benzene ring and a naphthalene ring, and a benzene ring is preferable.
Examples of the aliphatic ring having 4 to 18 carbon atoms represented by the ring W ² include the following rings, which are represented by the ring represented by the formula (W ² -a) or the formula (W ² -b). A ring is preferred.

Examples of the sulfonate anion constituting the salt (I) include the following.

Examples of the organic cation represented by Z ⁺ include an organic onium cation such as an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, and an organic phosphonium cation. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, and an arylsulfonium cation is more preferable.

More preferably, an organic cation represented by any of the following formulas (b2-1) to (b2-4) [hereinafter, depending on the number of each formula, “cation (b2-1)”, “cation” (B2-2) "," cation (b2-3) "and" cation (b2-4) ". ].

[In Formula (b2-1)-Formula (b2-4),
R ^b4 , R ^b5 and R ^b6 each independently represent an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the alkyl group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and is included in the alicyclic hydrocarbon group. The hydrogen atom may be substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms or a glycidyloxy group, and the hydrogen atom contained in the aromatic hydrocarbon group is a halogen atom, a hydroxy group, or a carbon number of 1 It may be substituted with an aliphatic hydrocarbon group having 18 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Further, R ^b4 and R ^b5 may be combined to form a ring which may further have a hetero atom together with the sulfur atom to which they are bonded.
The ring in which R ^b4 and R ^b5 may have a hetero atom may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. If it contains one or more sulfur atoms, it may further contain one or more sulfur atoms and / or one or more oxygen atoms. As the ring, a ring having 3 to 18 carbon atoms is preferable, and a ring having 4 to 13 carbon atoms is more preferable.

R ^b7 and R ^b8 each independently represent a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5.

R ^b9 and R ^b10 each independently represent an alkyl group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms.
R ^b11 represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^{b9 to} R ^b11 may be the same or different from each other. As for carbon number of this alkyl group, 1-12 are preferable. As for carbon number of this alicyclic hydrocarbon group, 4-12 are preferable.

^Rb12 represents a C1- ^C12 alkyl group, a C3- ^C18 alicyclic hydrocarbon group, or a C6-C18 aromatic hydrocarbon group. The hydrogen atom contained in the aromatic hydrocarbon group is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkyl group having 1 to 12 carbon atoms. It may be substituted with an alkylcarbonyloxy group.
R ^b9 and R ^b10 and / or R ^b11 and R ^b12 are independently bonded to each other, and together with the atoms to which they are bonded, a 3- to 12-membered ring (preferably a 3- to 7-membered ring) The methylene group contained in these rings may be replaced with an oxygen atom, a sulfur atom or a carbonyl group.

R ^{b13 to} R ^b18 each independently represent a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b11 represents an oxygen atom or a sulfur atom.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, the plurality of R ^b13 may be the same or different from each other. When p2 is 2 or more, the plurality of R ^b14 may be the same or different from each other, and q2 is When it is 2 or more, the plurality of R ^b15 may be the same as or different from each other. When r2 is 2 or more, the plurality of R ^b16 may be the same or different from each other, and s2 is 2 or more. In this case, the plurality of R ^b17 may be the same as or different from each other, and when t2 is 2 or more, the plurality of R ^b18 may be the same as or different from each other. ]

Examples of the alkylcarbonyloxy group include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group. Group, pentylcarbonyloxy group, hexylcarbonyloxy group, octylcarbonyloxy group, 2-ethylhexylcarbonyloxy group and the like.
Preferred alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl and 2-ethylhexyl.

Preferred alicyclic hydrocarbon groups are cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclodecyl group, 2-alkyladamantan-2-yl group, 1- (adamantan-1-yl) alkane- 1-yl group and isobornyl group.
Preferred aromatic hydrocarbon groups are phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-methoxyphenyl group, biphenylyl group and naphthyl group. It is.
Examples of the alkyl group (aralkyl group) in which a hydrogen atom is substituted with an aromatic hydrocarbon group include a benzyl group.

Examples of the ring formed by combining R ^b9 and R ^b10 together with the sulfur atom to which they are bonded include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and 1, 4-oxathian-4-ium ring etc. are mentioned.
Examples of the ring formed by combining R ^b11 and R ^b12 with each carbon atom of the methine group and carbonyl group to which they are bonded include oxocycloheptane ring, oxocyclohexane ring, oxonorbornane ring and oxoadamantane ring. Etc.

  Specific examples of the organic cation represented by each of the formulas (b2-1) to (b2-4) include cations described in JP2010-204646A.

Among them, a cation (b2-1) is preferable, an organic cation represented by the following formula (b2-1-1) [hereinafter referred to as “cation (b2-1-1)”] is more preferable, and a triphenylsulfonium cation (In formula (b2-1-1), v2, w2 and x2 are all 0.), Tolylylsulfonium cation (in formula (b2-1-1), v2, w2 and x2 are both 1. R ^b19 , R ^b20 and R ^b21 are all methyl groups) or di-t-butylphenylphenylsulfonium cation (in formula (b2-1-1), v2 and w2 are 1 and x2 is 0 , R ^b19 and R ^b20 are t-butyl groups).

[In the formula (b2-1-1),
R ^b19 , R ^b20 and R ^b21 are each independently a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or carbon. The number 1-12 alkoxy group is represented. ^{Two members} selected from R ^b19 to R ^b21 may be combined to form a ring that may further have a heteroatom together with a benzene ring and a sulfur atom to which they are bonded.
v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, a plurality of R ^b19 may be the same as or different from each other. When w2 is 2 or more, a plurality of R ^b20 may be the same or different from each other. When x2 is 2 or more, a plurality of R ^{b19 b21} may be the same as or different from each other. ]

In formula (b2-1-1), the alkyl group preferably has 1 to 12 carbon atoms, and the hydrogen atom contained in the alkyl group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or an aromatic group having 6 to 18 carbon atoms. It may be substituted with a group hydrocarbon group.
The alicyclic hydrocarbon group preferably has 4 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms or a glycidyloxy group. May be.
Among them, R ^b19 , R ^b20 and R ^b21 are preferably each independently a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. It is.

Examples of the cation (b2-1) include the following cations.

Examples of the cation (b2-2) include the following cations.

Examples of the cation (b2-3) include the following cations.

The salt (I) is a combination of a sulfonate anion and an organic cation, and the sulfonate anion and the organic cation can be arbitrarily combined.
As salt (I), the salt of Table 1 and 2 is mentioned, for example.

Of these, the salts shown below are preferred.

［式中、Ｑ^１、Ｑ^２、環Ｗ^１、環Ｗ^２、Ｒ^１、Ｒ^２、ｓ、ｔ及びＺ^＋は、それぞれ上記と同じ意味を表す。Ｒ^３は、炭素数１〜１４の飽和炭化水素基を表す。］ Next, the manufacturing method of salt (I) is demonstrated.
For example, L ¹ is * —CO—O—CHR ³ — (* represents a bond with C (Q ¹ ) (Q ² )), and L ³ -L ² is * —O—CH ₂ —. A method for producing a salt represented by the formula (IA) which is CO—O— (* represents a bond to ring W ¹ ) is shown below.

[Wherein, Q ¹ , Q ² , ring W ¹ , ring W ² , R ¹ , R ² , s, t and Z ⁺ each represent the same meaning as described above. R ³ represents a saturated hydrocarbon group having 1 to 14 carbon atoms. ]

［Ｙ^１及びＹ^２は、ハロゲン原子を表す。］
ハロゲン原子としては、フッ素原子、塩素原子、臭素原子及びヨウ素原子が挙げられる。Ｙ^１とＹ^２とはそれぞれ異なっていてもよいが、ともに塩素原子であることが好ましい。 A compound represented by formula (IA-c) can be obtained by reacting a compound represented by formula (IA-a) with a compound represented by formula (IA-b) under a basic catalyst. it can. Examples of the solvent include tetrahydrofuran. Examples of the base catalyst include pyridine.

[Y ¹ and Y ² represent a halogen atom. ]
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Y ¹ and Y ² may be different from each other, but both are preferably chlorine atoms.

Examples of the compound represented by the formula (IA-a) include compounds represented by the following.

Examples of the compound represented by the formula (IA-b) include compounds represented by the following.

Moreover, the compound represented by the following as a compound represented by a formula (IA-c) can be easily obtained from a market.

By reacting the compound represented by the formula (IA-c) and the compound represented by the formula (IA-d) in a solvent in the presence of a catalyst, the compound represented by the formula (IA-e) is obtained. Can be obtained. Examples of the solvent include tetrahydrofuran. Examples of the catalyst include pyridine.

Examples of the compound represented by the formula (IA-d) include compounds represented by the following.

The compound represented by the formula (IA-f) can be obtained by reducing the compound represented by the formula (IA-e) in a solvent. Examples of the solvent include acetonitrile. Examples of the reducing agent include sodium borohydride.

The salt represented by the formula (IA-i) can be obtained by reacting the salt represented by the formula (IA-g) with the compound represented by the formula (IA-h).
The salt represented by the formula (IA-g) can be synthesized, for example, by the method described in JP-A-2008-13551.

The salt represented by the formula (IA) can be obtained by reacting the compound represented by the formula (IA-f) and the salt represented by the formula (IA-i) in a solvent. Examples of the solvent include acetonitrile.

  The acid generator of the present invention contains a salt (I). The acid generator of the present invention may contain one or more salts (I). Further, the acid generator of the present invention is a salt known as an acid generator other than the salt (I) (for example, an organic cation contained in the salt (I) and a known anion (salt (I)). And a sulfonate anion contained in the salt (I) and a known cation (a salt comprising a cation other than the organic cation contained in the salt (I), etc.). . Hereinafter, salts other than the salt (I) contained in the acid generator of the present invention may be referred to as “acid generator (B)”.

As an acid generator (B), Preferably, the salt represented by either of Formula (B1-1)-Formula (B1-26) is mentioned, for example. Among them, those containing a triarylsulfonium cation are preferable. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-5), Formula (B1-6), Formula (B1- 7), formula (B1-11), formula (B1-12), formula (B1-13), formula (B1-14), formula (B1-21), formula (B1-22), formula (B1-23) ), A formula (B1-24), a formula (B1-25) and a salt represented by any one of formulas (B1-26) are more preferable.

The total amount of the acid generator of the present invention may be salt (I).
When the acid generator of the present invention contains the salt (I) and the acid generator (B), the content of the salt (I) is preferably 10 masses with respect to 100 parts by mass of the total amount of the acid generator of the present invention. Part or more (more preferably 30 parts by weight or more), preferably 90 parts by weight or less (more preferably 70 parts by weight or less).
Next, the resist composition of the present invention will be described. The resist composition of the present invention comprises the acid generator of the present invention and a resin, and the resin has an acid-labile group and is an insoluble or hardly soluble resin in an alkaline aqueous solution. Thus, it is a resin that can be dissolved in an alkaline aqueous solution (hereinafter referred to as “resin (A)”).
The content of the acid generator of the present invention is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 30 parts by mass or less (more preferably 25 parts by mass) with respect to 100 parts by mass of the resin (A). Part or less).

<Resin (A)>
The resin (A) is insoluble or hardly soluble in an aqueous alkali solution and becomes alkali-soluble by the action of an acid. “Becomes alkali-soluble by the action of an acid” means insoluble or hardly soluble in an aqueous alkali solution before contact with an acid, but becomes soluble in an aqueous alkali solution after contact with an acid.
In such a resin (A), a part or all of the hydrophilic group in the molecule is protected by a protecting group that can be removed by contact with an acid, and the resin (A) is in contact with an acid. Then, the protective group is eliminated and a hydrophilic group is generated, so that the resin (A) becomes a resin soluble in an alkaline aqueous solution. The hydrophilic group protected by the protecting group is hereinafter referred to as “acid labile group”. Examples of the hydrophilic group include a hydroxy group or a carboxy group, and a carboxy group is more preferable.
The resin (A) can be produced by polymerizing a monomer having an acid labile group (hereinafter sometimes referred to as “acid labile monomer (a1)”). In the polymerization, only one type of monomer (a1) may be used, or two or more types may be used in combination.

<Acid labile monomer (a1)>
“Acid labile group” means a group having a leaving group, which is removed by contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group). To do. Examples of the acid labile group include a group represented by the formula (1).

[In formula (1), R ^<a1 > -R < ^a3 > respectively independently represents a C1-C8 alkyl group, a C3-C20 alicyclic hydrocarbon group, or the group which combined these, or R ^a1 and R ^a2 are bonded to each other to form a divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms. * Represents a bond. ]

^Examples of the alkyl group of R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
Examples of the alicyclic hydrocarbon group include a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following formula: And polycyclic alicyclic hydrocarbon groups such as groups.
Examples of the group combining an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, and a methylnorbornyl group.

Preferably carbon number of the alicyclic hydrocarbon group in Formula (1) is 3-16.
The carbon number of the divalent aliphatic hydrocarbon group formed by combining R ^a1 and R ^a2 with each other is preferably 3-12.
Examples of —C (R ^a1 ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R ^a2 are bonded to each other to form a divalent aliphatic hydrocarbon group include the following groups.

［式（１−１）、式（１−２）、式（１−３）中、Ｒ^ａ１１〜Ｒ^ａ１７は、それぞれ独立に、炭素数１〜８のアルキル基を表す。］ Examples of the group represented by the formula (1) include a group represented by the formula (1-1), the formula (1-2), the formula (1-3), or the formula (1-4). .

[In formula (1-1), formula (1-2), and formula (1-3), R ^{a11 to} R ^a17 each independently represents an alkyl group having 1 to 8 carbon atoms. ]

Preferably, tert-butoxycarbonyl group, 1-methylcyclohexane-1-yloxycarbonyl group, 1-ethylcyclohexane-1-yloxycarbonyl group, 2-methyladamantan-2-yloxycarbonyl group, 2-ethyladamantane- Examples include 2-yloxycarbonyl group, 2-isopropyladamantan-2-yloxycarbonyl group, 1- (adamantan-1-yl) -1-methylethoxycarbonyl group, and the like.
Among these, the group represented by Formula (1-2), Formula (1-3), or Formula (1-4) having an alicyclic hydrocarbon group is preferable, and Formula (1-2) or Formula (1) is preferable. The group represented by -3) is more preferable.

［式（２）中、Ｒ^ａ１’及びＲ^ａ２’は、それぞれ独立に、水素原子又は炭素数１〜１２の１価の炭化水素基を表し、Ｒ^ａ３’は、炭素数１〜２０の１価の炭化水素基を表すか、Ｒ^ａ２’及びＲ^ａ３’は互いに結合して炭素数２〜２０の２価の炭化水素基を形成し、前記１価の炭化水素基及び前記２価の炭化水素基に含まれるメチレン基は、酸素原子又は硫黄原子で置き換わっていてもよい。＊は結合手を表す。］ Examples of the acid labile group include a group represented by the formula (2).

[In Formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents 1 having 1 to 20 carbon atoms. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and the monovalent hydrocarbon group and the divalent carbon group The methylene group contained in the hydrogen group may be replaced with an oxygen atom or a sulfur atom. * Represents a bond. ]

Examples of the hydrocarbon group for R ^{a1 ′} and R ^{a2 ′} include an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group.
Aromatic hydrocarbon groups include phenyl, naphthyl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl, anthryl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.
Preferably, at least one of R ^{a1 ′} and R ^{a2 ′} is a hydrogen atom.

Specific examples of the group represented by the formula (2) include the following groups.

The acid labile monomer (a1) is preferably one having an alicyclic hydrocarbon group having 5 to 20 carbon atoms. If the resin (A) is a resin obtained by polymerizing the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group, the resolution of the resist can be improved.
The acid labile monomer (a1) is preferably a monomer having a group represented by the formula (1) and an ethylenic carbon-carbon double bond, and more preferably a group represented by the formula (1) It is a monomer having a (meth) acryl group.

Preferred examples of the monomer having a group represented by the formula (1) and a (meth) acryl group include a monomer represented by the formula (a1-1) and a monomer represented by the formula (a1-2). These may be used alone or in combination of two or more.

[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or * —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bond to —CO—. Represents a hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or a group obtained by combining these.
m1 represents the integer of 0-14.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ]

L ^a1 and L ^a2 are preferably —O— or * —O— (CH ₂ ) _k1 —CO—O— (k1 is preferably an integer of 1 to 4, more preferably 1). More preferably, it is —O—.
R ^a4 and R ^a5 are preferably methyl groups.
^Examples of the alkyl group for R ^a6 and R ^a7 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. The alkyl group for R ^a6 and R ^a7 preferably has 6 or less carbon atoms.

The alicyclic hydrocarbon group for R ^a6 and R ^a7 may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, Examples thereof include cycloalkyl groups such as cycloheptyl group and cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups.

The alicyclic hydrocarbon group preferably has 8 or less carbon atoms, more preferably 6 or less.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 ′ is preferably 0 or 1, more preferably 1.

Examples of the monomer represented by the formula (a1-1) include monomers described in JP 2010-204646 A. A monomer represented by any one of formula (a1-1-1) to formula (a1-1-8) is preferred, and represented by any one of formula (a1-1-1) to formula (a1-1-4). More preferred is a monomer.

Examples of the monomer represented by the formula (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, 1-ethylcycloheptane-1 -Yl (meth) acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, 1-methylcyclohexane-1-yl (meth) acrylate, 1-isopropylcyclohexane-1-yl (meth) acrylate, etc. . A monomer represented by any one of formula (a1-2-1) to formula (a1-2-12) is preferable, and the formula (a1-2-3), formula (a1-2-4), and formula (a1- 2-9), a monomer represented by any one of formulas (a1-2-10) is more preferred, and a monomer represented by formula (a1-2-3) or formula (a1-2-9) is more preferred. .

When the resin (A) includes a structural unit derived from the monomer represented by the formula (a1-1) and / or the monomer represented by the formula (a1-2), the total content thereof is the resin (A). The total structural unit is generally 10 to 95 mol%, preferably 15 to 90 mol%, more preferably 20 to 85 mol%, still more preferably 30 to 60 mol%.
Especially, it is preferable that the content rate of the structural unit derived from the monomer represented by Formula (a1-1) is 15 mol% or more with respect to the structural unit derived from the acid labile monomer (a1). When the ratio of the monomer having an adamantyl group is increased, the dry etching resistance of the resist pattern is improved.

［式（ａ１−５）中、
Ｒ^３１は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｚ^ａ１は、単結合又は＊−［ＣＨ_２］_ｋ４−ＣＯ−Ｌ^ａ４−を表す。ここで、ｋ４は１〜４の整数を表す。＊は、Ｌ^ａ１との結合手を表す。
Ｌ^ａ１、Ｌ^ａ２、Ｌ^ａ３及びＬ^ａ４は、それぞれ独立に、−Ｏ−又は−Ｓ−を表す。
ｓ１は、１〜３の整数を表す。
ｓ１’は、０〜３の整数を表す。］ As the other monomer (a1), for example, a monomer represented by the formula (a1-5) (hereinafter sometimes referred to as “monomer (a1-5)”) may be used.

[In the formula (a1-5),
R ³¹ represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ^a1 represents a single bond or * — [CH ₂ ] _k4 —CO—L ^a4 —. Here, k4 represents an integer of 1 to 4. * Represents a bond with L ^a1 .
L ^a1 , L ^a2 , L ^a3 and L ^a4 each independently represent —O— or —S—.
s1 represents an integer of 1 to 3.
s1 ′ represents an integer of 0 to 3. ]

In formula (a1-5), R ³¹ is preferably a hydrogen atom, a methyl group, or a trifluoromethyl group.
L ^a1 is preferably an oxygen atom.
One of L ^a2 and L ^a3 is preferably an oxygen atom and the other is a sulfur atom.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or * —CH ₂ —CO—O—.

Examples of the monomer (a1-5) include the following monomers.

When the resin (A) has a structural unit derived from the monomer (a1-5), the content is preferably from 1 to 95 mol%, more preferably from 3 to 90 mol, based on all structural units of the resin (A). % Is more preferable, and 5-85 mol% is more preferable.
The resin (A) preferably further contains a structural unit derived from a monomer having no acid-labile group (hereinafter sometimes referred to as “acid-stable monomer”). An acid stable monomer may be used individually by 1 type, and may use 2 or more types together.
As an acid stable monomer, Preferably, the monomer which has a hydroxyl group or a lactone ring is mentioned. The resin (A) is an acid-stable monomer containing a structural unit and / or lactone ring derived from an acid-stable monomer having a hydroxy group (hereinafter sometimes referred to as “acid-stable monomer (a2)”) (hereinafter “acid-stable monomer”). By having the structural unit derived from (sometimes referred to as (a3) ”), the resolution of the resist pattern and the adhesion between the resist pattern and the substrate can be improved.

<Acid-stable monomer having a hydroxy group (a2)>
When the resist composition containing the resin (A) is used for KrF excimer laser exposure (248 nm) or irradiation with high energy rays such as an electron beam or EUV light, the acid stable monomer (a2) is an acid having a phenolic hydroxy group. Stable monomer (a2-0) is preferred. When used for ArF excimer laser exposure (193 nm) or the like, the acid-stable monomer (a2) having a hydroxy group is preferably an acid-stable monomer having a hydroxyadamantyl group represented by the formula (a2-1). The acid-stable monomer (a2) having a hydroxy group may be used alone or in combination of two or more.

［式（ａ２−０）中、
Ｒ^ａ３０は、水素原子、ハロゲン原子又はハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。
Ｒ^ａ３１は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｍａは０〜４の整数を表す。ｍａが２以上である場合、複数のＲ^ａ３１は互いに同一であるか相異なる。］ Examples of the monomer having a phenolic hydroxy group include a monomer represented by the formula (a2-0).

[In the formula (a2-0),
R ^a30 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a31 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or Represents a methacryloyloxy group.
ma represents an integer of 0 to 4. When ma is 2 or more, the plurality of R ^a31 are the same or different from each other. ]

Examples of the halogen atom in R ^a30 and R ^a31 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
^Examples of the alkyl group which may have a halogen atom of R ^a30 include, for example, a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, and a perfluorotert-butyl group. Perfluoropentyl group, perfluorohexyl group, trichloromethyl group, tribromomethyl group, triiodomethyl group and the like.
^Examples of the alkyl group in R ^a30 and R ^a31 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. Can be mentioned. R ^a30 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and particularly preferably a methyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, and an n-hexoxy group. , Preferably, it is a C1-C4 alkoxy group, More preferably, it is a C1-C2 alkoxy group, Most preferably, it is a methoxy group.

Examples of the acyl group for R ^a31 include an acetyl group, a propionyl group, and a butyryl group.
Examples of the acyloxy group for R ^a31 include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
ma is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.

  A copolymer having a structural unit derived from a monomer having a phenolic hydroxy group is obtained by radically polymerizing a monomer in which the phenolic hydroxy group is protected with a protecting group and a monomer to be copolymerized and then deprotecting with an acid or base. Can be manufactured. Since the resin (A) has a structural unit derived from the acid labile group monomer (a1), when deprotecting the phenolic hydroxy group protected by the protecting group, the acid labile group is removed. It is preferable to deprotect by contact with a base so as not to be significantly impaired. As the protecting group, for example, an acetyl group is preferable. Examples of the base include 4-dimethylaminoviridine, triethylamine and the like.

As a monomer which has a phenolic hydroxy group, the monomer described in Unexamined-Japanese-Patent No. 2010-204634 is mentioned, for example. Monomers represented by formula (a2-0-1) and formula (a2-0-2) are preferred.

  When the resin (A) includes a structural unit derived from the monomer represented by the formula (a2-0), the content is usually 5 to 90 mol% with respect to all the structural units of the resin (A). , Preferably it is 10-85 mol%, More preferably, it is 15-80 mol%.

Examples of the acid stable monomer having a hydroxyadamantyl group include a monomer represented by the formula (a2-1).

[In the formula (a2-1),
L ^a3 represents —O— or * —O— (CH ₂ ) _k2 —CO—O—,
k2 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents an integer of 0 to 10.
In Formula (a2-1), L ^a3 is preferably —O—, * —O— (CH ₂ ) _f1 —CO—O— (wherein f1 is an integer of 1 to 4) (* is − Represents a bond with CO-), more preferably -O-.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1. ]

As an acid stable monomer (a2-1) which has a hydroxyadamantyl group, the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. A monomer represented by any one of formula (a2-1-1) to formula (a2-1-6) is preferable, and represented by any one of formula (a2-1-1) to formula (a2-1-4). The monomer represented by Formula (a2-1-1) or Formula (a2-1-3) is more preferable.

  When the resin (A) includes a structural unit derived from the monomer represented by the formula (a2-1), the content is usually 3 to 45 mol% with respect to all the structural units of the resin (A). , Preferably it is 5-40 mol%, More preferably, it is 5-35 mol%, More preferably, it is 5-15 mol%.

<Acid-stable monomer (a3) having a lactone ring>
The lactone ring possessed by the acid stable monomer (a3) may be, for example, a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, and a monocyclic lactone ring and other rings The condensed ring may be used. Among these lactone rings, a γ-butyrolactone ring or a condensed ring of γ-butyrolactone ring and another ring is preferable.

The acid-stable monomer (a3) having a lactone ring is preferably represented by the formula (a3-1), the formula (a3-2) or the formula (a3-3). These 1 type may be used independently and may use 2 or more types together.

[In Formula (a3-1)-Formula (a3-3),
L ^{a4 to} L ^a6 each independently represent —O— or * —O— (CH ₂ ) _k3 —CO—O—.
k3 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^{a18 to} R ^a20 each independently represents a hydrogen atom or a methyl group.
R ^a21 represents an alkyl group having 1 to 4 carbon atoms.
p1 represents an integer of 0 to 5. When p1 is 2 or more, the plurality of R ^a21 are the same or different from each other.
R ^a22 and R ^a23 each independently represent a carboxy group, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
q1 and r1 each independently represents an integer of 0 to 3. When q1 is 2 or more, the plurality of R ^a22 are the same or different from each other, and when r1 is 2 or more, the plurality of R ^a23 are the same or different from each other.
L ^{a4 to} La ^{6 in} formula (a3-1) to formula (a3-3) are each independently —O— or * —O— (CH ₂ ) _k3 —CO—O— (k3 is It is preferably an integer of 1 to 4, more preferably 1.), and more preferably —O—.
R ^{a18 to} R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are each independently preferably 0 to 2, more preferably 0 or 1. ]

Examples of the acid-stable monomer (a3) having a lactone ring include monomers described in JP 2010-204646 A. Formula (a3-1-1) to Formula (a3-1-4), Formula (a3-2-1) to Formula (a3-2-4), Formula (a3-3-1) to Formula (a3-3) -4) is preferred, and the monomer represented by formula (a3-1-1), formula (a3-1-2), formula (a3-2-3) or formula (a3-2-4) is preferred. The monomer represented by either is more preferable, and the monomer represented by the formula (a3-1-1) or the formula (a3-2-3) is more preferable.

  When the resin (A) includes a structural unit derived from the acid-stable monomer (a3) having a lactone ring, the content is usually 5 to 70 mol% with respect to all the structural units of the resin (A). , Preferably it is 10-65 mol%, More preferably, it is 10-60 mol%.

<Other monomer (a4)>
The resin (A) may have a structural unit derived from another monomer other than the above monomer (hereinafter sometimes referred to as “monomer (a4)”). A known monomer can be used as the other monomer (a4).
A preferred resin (A) is a copolymer obtained by polymerizing the monomer (a1), the acid stable monomer (a2) and / or the acid stable monomer (a3). In this preferable copolymer, it is preferable to use at least one of the above-mentioned monomer (a1-1) and monomer (a1-2) as monomer (a1), and it is more preferable to use monomer (a1-1). . The acid stable monomer (a2) is preferably an acid stable monomer (a2-1), and the acid stable monomer (a3) is at least one of an acid stable monomer (a3-1) and an acid stable monomer (a3-2). Is preferred.

Resin (A) uses monomer (a1) and, if necessary, an acid-stable monomer selected from the group consisting of acid-stable monomer (a2), acid-stable monomer (a3) and acid-stable monomer (a4), After adjusting the amount of use such that these are suitable for the total structural unit of the resin (A) as described above, it can be produced by a known polymerization method (for example, radical polymerization method).
The weight average molecular weight of the resin (A) is preferably 2,500 or more, more preferably 3,000 or more. The upper limit of the weight average molecular weight is preferably 50,000 or less, and more preferably 30,000 or less. In addition, the weight average molecular weight here is calculated | required as a conversion value of a standard polystyrene reference | standard by gel permeation chromatography analysis, and the detailed analysis conditions of this analysis are explained in full detail in the Example of this application.

<Basic Compound (hereinafter referred to as “Basic Compound (C)”)>
The resist composition of the present invention may further contain a basic compound (C). The term “basic compound” as used herein means a compound having a property of capturing an acid, particularly a compound having a property of capturing an acid generated from an acid generator described above. It is said to be char.

The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium hydroxides. The amine may be an aliphatic amine or an aromatic amine. The aliphatic amine may be any of primary amine, secondary amine and tertiary amine. The aromatic amine may be either an aromatic ring such as aniline with an amino group bonded thereto or a heteroaromatic amine such as pyridine. Preferable basic compounds (C) include aromatic amines represented by the following formula (C2), particularly anilines represented by the following formula (C2-1).

[Wherein Ar ^c1 represents an aromatic hydrocarbon group.
R ^c5 and R ^c6 are each independently a hydrogen atom or an aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms). ), An alicyclic hydrocarbon group (preferably an alicyclic hydrocarbon group having 5 to 10 carbon atoms) or an aromatic hydrocarbon group (preferably an aromatic hydrocarbon having 6 to 10 carbon atoms). A hydrogen atom contained in the aliphatic hydrocarbon group, the alicyclic hydrocarbon group, and the aromatic hydrocarbon group is a hydroxy group, an amino group, or an alkoxy having 1 to 6 carbon atoms. It may be substituted with a group, and the amino group may further have an alkyl group having 1 to 4 carbon atoms.
R ^c7 is an aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms), or 1 to 6 carbon atoms. An alkoxy group, an alicyclic hydrocarbon group (preferably an alicyclic hydrocarbon group having 5 to 10 carbon atoms, and more preferably a cycloalkyl group having 5 to 10 carbon atoms), an aromatic hydrocarbon. Represents a group (preferably an aromatic hydrocarbon group having 6 to 10 carbon atoms) or a nitro group, the aliphatic hydrocarbon group, the alkoxy group, the alicyclic hydrocarbon group and the aromatic hydrocarbon. The hydrogen atom contained in the group may be substituted with a hydroxy group, an amino group, or an alkoxy group having 1 to 6 carbon atoms, and the amino group further has an alkyl group having 1 to 4 carbon atoms. Also good.
m3 represents an integer of 0 to 3. When m3 is 2 or more, the plurality of R ^c7 may be the same as or different from each other. ]

Examples of the aromatic amine represented by the formula (C2) include 1-naphthylamine and 2-naphthylamine.
Examples of the anilines represented by the formula (C2-1) include aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline and diphenylamine. Is mentioned.

Any of the following formulas (C3), (C4), (C5), (C6), (C7), (C8), (C9), (C10), and (C11) (Hereinafter, these compounds are expressed as “compound (C3)” to “compound (C11)” depending on the formula number).

[here,
R ^c8, and, ^R c 20 to bind to aromatic ^{carbon, R c21, R c23, R} c24, R c25, R c26, R c27 and ^{R c 28} represents any of the groups described in the ^{R c7.}
R ^c9 , R ^c10 , R ^c11 , R ^c12 , R ^c13 , R ^c14 , R ^c16 , R ^c17 , R ^c18 , R ^c19 and R ^c22 bonded to the nitrogen atom are independently R ^c5 and R ^c6 . Represents any of the groups described.
o3, p3, q3, r3, s3, t3 and u3 each independently represents an integer of 0 to 3. When o3 is 2 or more, the plurality of R ^c20 may be the same or different from each other. When p3 is 2 or more, the plurality of R ^c21 may be the same or different from each other, and when q3 is 2 or more, A plurality of R ^{c24 s} may be the same as or different from each other. When r3 is 2 or more, a plurality of R ^c25s may be the same as or different from each other, and when s3 is 2 or more, a plurality of R ^c26s may be the same as each other may be different, when t3 is 2 or more, plural R ^c27 may be the same or different from each other, when u3 is 2 or more, plural R ^{c 28} may be the same or different from each other.

R ^c15 is an aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms), an alicyclic hydrocarbon group (preferably an alicyclic hydrocarbon having 3 to 6 carbon atoms). Or an alkanoyl group (preferably an alkanoyl group having 2 to 6 carbon atoms).
Examples of the alkanoyl group include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pentanoyl group, and a 2,2-dimethylpropionyl group.
n3 represents an integer of 0 to 8. When n3 is 2 or more, the plurality of R ^c15 may be the same as or different from each other.
L ^c1 and L ^c2 are each independently a divalent aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, more preferably an alkylene group having about 1 to 6 carbon atoms). ), A carbonyl group, —C (═NH) —, —C (═NR ^c3 ) — (wherein R ^c3 represents an alkyl group having 1 to 4 carbon atoms), a thioxy group (—S—). ), A disulfide bond (—S—S—) or a combination thereof. ]

  Examples of the basic compound (C3) include hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine , Tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyl Dioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyl Hexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine ethylenediamine, tetramethylenediamine, hexa Use methylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, etc. Can do.

Examples of the compound (C4) include piperazine.
Examples of the compound (C5) include morpholine.
Examples of the compound (C6) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound (C7) include 2,2′-methylenebisaniline.
Examples of the compound (C8) include imidazole and 4-methylimidazole.
Examples of the compound (C9) include pyridine and 4-methylpyridine.
Examples of the compound (C10) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1,2-di ( 4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide, 4,4 Examples include '-dipyridyl disulfide, 2,2'-dipyridylamine, and 2,2'-dipicolylamine.
Examples of the compound (C11) include bipyridine.

Examples of ammonium hydroxide include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, and 3- (trifluoromethyl). Examples thereof include phenyltrimethylammonium hydroxide, tetra-n-butylammonium salicylate and choline.
Among these, as the basic compound (C), diisopropylaniline and tetra-n-butylammonium salicylate are preferable.

<Solvent (hereinafter referred to as “solvent (D)”)>
The resist composition of the present invention preferably contains a solvent (D). The solvent (D) is a resist pattern, which will be described later, according to the type and amount of the salt (I) used, the type and amount of the resin (A), and the type and amount of the acid generator (B). In the production of the above, an optimum one can be appropriately selected from the viewpoint that the coating property when the resist composition is coated on the substrate is improved.
Examples of suitable solvents (D) include 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; ethyl lactate, butyl acetate, amyl acetate and Examples thereof include esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; and cyclic esters such as γ-butyrolactone. Only 1 type may be used for a solvent (D) and it may use 2 or more types together.

<Other ingredients>
The resist composition of the present invention may contain components other than those described above (hereinafter may be referred to as “component (F)”) as necessary. Component (F) is not particularly limited, and additives known in the art, for example, polymer compounds other than resin (A), sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, etc. Can be mentioned.

<The resist composition of the present invention and its preparation method>
The resist composition of the present invention comprises a salt (I), a resin (A), a solvent (D), an acid generator (B), a basic compound (C) and / or a component (F) used as necessary. It can be prepared by mixing. The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing may be selected from an appropriate temperature range from 10 to 40 ° C. according to the type of salt (I) to be used and the solubility in the solvent (D) such as salt (I). The time is preferably 0.5 to 24 hours depending on the mixing temperature. In addition, a mixing means is not specifically limited, Stirring mixing etc. can be used.

By selecting the amount of each component used when preparing the resist composition of the present invention, the content of each component in the resist composition of the present invention can be adjusted.
Thus, after mixing each component, it is preferable to filter using a filter with a pore size of about 0.003 to 0.2 μm.
It is preferable that content of resin (A) in the resist composition of this invention is 80 to 99 mass% with respect to the total mass of solid content of a resist composition.

In the present specification, “solid content of the composition” means the total of resist composition components excluding the solvent (D) described later. For example, in the resist composition of the present invention in which the content of the solvent (D) is 90% by mass, the solid content of the resist composition corresponds to 10% by mass. The solid content of the composition and the content of each component relative thereto can be measured by known analytical means such as liquid chromatography or gas chromatography, for example.
The content of the salt (I) in the resist composition of the present invention is preferably 0.01 to 40% by mass, more preferably 1 to 30% by mass, with respect to the total mass of the solid content of the resist composition. 25 mass% is further more preferable.

When the resist composition of the present invention contains an acid generator (B), the content thereof is preferably 0.01 parts by mass or more, more preferably 1 part by mass with respect to 100 parts by mass of the resin (A). It is above, More preferably, it is 3 mass parts or more. The acid generator (B) is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and further preferably 20 parts by mass or less with respect to 100 parts by mass of the resin (A).
When the resist composition of the present invention contains a basic compound (C), the content of the basic compound (C) with respect to the total mass of the solid content of the resist composition is preferably about 0.01 to 1% by mass. The content of the basic compound (C) is preferably lower than the total content of the salt (I) and the acid generator (B).

The content of the solvent (D) in the resist composition of the present invention is preferably 90% by mass or more, more preferably 92% by mass or more, and further preferably 94% by mass or more with respect to the total mass of the resist composition. 99.9% by mass or less, and more preferably 99% by mass or less. The resist composition of the present invention containing the solvent (D) with such a content easily forms a composition layer having a thickness of about 30 to 300 nm in the production of a resist pattern.
In addition, when using a component (F) for the resist composition of this invention, suitable content can be adjusted according to the kind of the said component (F).

<Method for producing resist pattern>
The method for producing a resist pattern of the present invention comprises:
(1) A step of applying the resist composition of the present invention on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) The process of heating the composition layer after exposure, and (5) The process of developing the composition layer after a heating are included. Hereinafter, each of the steps shown here is referred to as “step (1)” to “step (5)”.

  The application of the resist composition of the present invention on the substrate in the step (1) can be performed by a coating apparatus widely used for applying a resist material for semiconductor microfabrication, such as a spin coater. The film thickness of the coating film can be adjusted by variously adjusting the conditions (coating conditions) of the coating apparatus, and by applying an appropriate preliminary experiment, the coating film can be applied to have a desired film thickness. You can choose the conditions. As the substrate before applying the resist composition of the present invention, various substrates to be subjected to fine processing can be selected. In addition, before apply | coating the resist composition of this invention, a board | substrate can be wash | cleaned or an antireflection film can also be formed. For example, a commercially available composition for an organic antireflection film can be used for forming the antireflection film. Thus, a coating film made of a resist composition is formed on the substrate.

In the step (2), the resist composition of the present invention applied on the substrate, that is, the coating film is dried to remove the solvent (D). Such drying is performed by, for example, heating means using a heating device such as a hot plate (so-called pre-baking), decompressing means using a decompressing device, or a combination of these means. The drying conditions can be selected according to the type of the solvent (D) contained in the resist composition of the present invention. For example, in a heating means using a hot plate, the surface temperature of the hot plate is set in the range of about 50 to 200 ° C. Preferably it is done. In the decompression unit, after the substrate on which the coating film is formed is sealed in the decompressor, the internal pressure of the decompressor may be set to about 1 to 1.0 × 10 ⁵ Pa. Thus, by drying the coating film, a composition layer is formed on the substrate.

Step (3) is a step of exposing the composition layer using an exposure machine. The exposure is performed through a mask (photomask) on which a desired pattern to be finely processed is formed. As an exposure light source of the exposure machine, an ultraviolet light source such as a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm), or a solid-state laser light source (YAG In addition, various lasers such as a laser beam from a laser beam from a semiconductor laser or the like to emit a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region can be used. The exposure machine may be an immersion exposure machine. The exposure machine may irradiate an electron beam or extreme ultraviolet light (EUV). In this specification, irradiating these radiations may be collectively referred to as “exposure”. When the exposure light source is an electron beam, a desired pattern may be directly drawn without using a photomask.

  As described above, by exposing through a mask, an exposed portion (exposed portion) and an unexposed portion (unexposed portion) are generated in the composition layer. In the composition layer of the exposed area, the salt (I) and the acid generator (B) contained in the composition layer generate an acid upon receiving exposure energy, and are further in the resin (A) by the action of the generated acid. Since the acid labile group generates a hydrophilic group by the deprotection reaction, the resin (A) in the composition layer of the exposed portion becomes soluble in the alkaline aqueous solution. On the other hand, since the exposure energy is not received in the unexposed area, the resin (A) remains insoluble or hardly soluble in the alkaline aqueous solution. Thus, the composition layer in the exposed portion and the composition layer in the unexposed portion are significantly different in solubility in the alkaline aqueous solution.

In step (4), the composition layer after exposure is subjected to heat treatment (so-called post-exposure baking). Such heat treatment is preferably the heating means using the hot plate shown in the step (2). When performing the heating means using a hot plate in the step (4), the surface temperature of the hot plate is preferably about 50 to 200 ° C, more preferably about 70 to 150 ° C. The deprotection reaction is promoted by the heat treatment.
Step (5) is a step of developing the heated composition layer using a developer, usually using a developing device. Examples of the developing method include a dipping method, a paddle method, a spray method, and a dynamic dispensing method. The development temperature is preferably 5 to 60 ° C., for example, and the development time is preferably 5 to 300 seconds, for example.

By selecting the type of developer, a positive resist pattern or a negative resist pattern can be produced.
When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline). The alkali developer may contain a surfactant.
It is preferable to wash the resist pattern with ultrapure water after development, and then remove the water remaining on the substrate and the pattern.

In the case of producing a negative resist pattern from the resist composition of the present invention, a developer containing an organic solvent as a developer (hereinafter sometimes referred to as “organic developer”) is used.
Organic solvents contained in the organic developer include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycols such as propylene glycol monomethyl ether Examples include ether solvents; amide solvents such as N, N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
In the organic developer, the content of the organic solvent is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and still more preferably only the organic solvent.
Among them, the organic developer is preferably a developer containing butyl acetate and / or 2-heptanone. In the organic developer, the total content of butyl acetate and 2-heptanone is preferably 50% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and substantially butyl acetate and / or 2 -More preferred is heptanone alone.
The organic developer may contain a surfactant. The organic developer may contain a trace amount of water.
At the time of development, the development may be stopped by substituting a solvent of a different type from the organic developer.

It is preferable to wash the developed resist pattern with a rinse solution. The rinsing liquid is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, and an alcohol solvent or an ester solvent is preferable.
After the cleaning, it is preferable to remove the rinse solution remaining on the substrate and the pattern.

<Application>
The resist composition of the present invention includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) irradiation or a resist composition for EUV exposure, and a liquid It is suitable as a resist composition for immersion exposure and can be used for fine processing of semiconductors.

  The present invention will be described more specifically with reference to examples. In the examples, “%” and “parts” representing the content or amount used are based on mass unless otherwise specified. The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions for gel permeation chromatography are as follows.

Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore HXL-M x 3 + 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)
Moreover, the structure of the compound was confirmed by measuring a molecular peak using mass spectrometry (LC: Model 1100 manufactured by Agilent, MASS: LC / MSD manufactured by Agilent). In the following examples, the value of this molecular peak is indicated by “MASS”.

式（Ｉ１−ｂ）で表される化合物９．４２部、テトラヒドロフラン２８．２６部及びピリジン６．０２部を反応器に仕込み、２３℃で３０分間攪拌した後、０℃まで冷却した。得られた混合物に、同温度を保持したまま、式（Ｉ１−ａ）で表される化合物１４．３６部を、１時間かけて添加した。さらに、温度を１０℃まで上げ、１０℃に到達した時点から、同温度で１時間攪拌した。得られた反応混合物に、酢酸エチル２００部、５％塩酸水溶液１２部及びイオン交換水１００部を加え、２３℃で３０分間攪拌し、静置後、分液した。回収された有機層に、イオン交換水１００部を加え、２３℃で３０分間攪拌した後、静置、分液することにより有機層を水洗した。このような水洗操作を４回繰り返した。回収された有機層を濃縮した後、以下の条件でカラム（シリカゲル６０−２００メッシュ；メルク社製 展開溶媒：酢酸エチル）分取することにより、式（Ｉ１−ｃ）で表される化合物９．８２部を得た。 Example 1: Synthesis of a salt represented by the formula (I-1)

9.42 parts of the compound represented by the formula (I1-b), 28.26 parts of tetrahydrofuran and 6.02 parts of pyridine were charged into a reactor, stirred at 23 ° C. for 30 minutes, and then cooled to 0 ° C. While maintaining the same temperature, 14.36 parts of the compound represented by the formula (I1-a) was added to the obtained mixture over 1 hour. Furthermore, the temperature was raised to 10 ° C., and when the temperature reached 10 ° C., the mixture was stirred at that temperature for 1 hour. To the obtained reaction mixture, 200 parts of ethyl acetate, 12 parts of a 5% aqueous hydrochloric acid solution and 100 parts of ion-exchanged water were added, stirred at 23 ° C. for 30 minutes, allowed to stand, and then separated. To the recovered organic layer, 100 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes, and then allowed to stand and liquid-separated to wash the organic layer with water. Such water washing operation was repeated 4 times. After the collected organic layer was concentrated, the compound (I1-c) represented by the formula (I1-c) was separated by fractionating a column (silica gel 60-200 mesh; developed solvent: ethyl acetate) under the following conditions. 82 parts were obtained.

式（Ｉ１−ｃ）で表される化合物６．１９部及びアセトニトリル１８．５７部を仕込み、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合物に、水素化ホウ素ナトリウム０．３６部及びイオン交換水５．３２部を仕込み、５℃で３時間攪拌した。得られた混合物に、イオン交換水３０部及び酢酸エチル１００部を加えて攪拌し、分離した。回収された有機層にイオン交換水３０部を加え、２３℃で３０分間攪拌した後、静置、分液することにより有機層を水洗した。このような水洗操作を５回繰り返した。回収された有機層を濃縮した後、以下の条件でカラム（シリカゲル６０−２００メッシュ；メルク社製 展開溶媒：酢酸エチル）分取することにより、式（Ｉ１−ｄ）で表される化合物３．８８部を得た。

6.19 parts of the compound represented by the formula (I1-c) and 18.57 parts of acetonitrile were charged, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixture, 0.36 part of sodium borohydride and 5.32 parts of ion-exchanged water were added and stirred at 5 ° C. for 3 hours. To the obtained mixture, 30 parts of ion-exchanged water and 100 parts of ethyl acetate were added, stirred and separated. 30 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, and then allowed to stand and liquid-separated to wash the organic layer with water. Such washing operation was repeated 5 times. After concentrating the collected organic layer, the compound (I1-d) represented by the formula (I1-d) is obtained by fractionating a column (silica gel 60-200 mesh; developing solvent: ethyl acetate, manufactured by Merck) under the following conditions. 88 parts were obtained.

式（Ｉ１−ｅ）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。
式（Ｉ１−ｅ）で表される塩５．００部及びアセトニトリル３０部を仕込み、４０℃で３０分間攪拌し、式（Ｉ１−ｆ）で表される化合物２．２２部を仕込み、５０℃で１時間攪拌することにより、式（Ｉ１−ｇ）で表される化合物を含む溶液を得た。

A salt represented by the formula (I1-e) was synthesized by the method described in JP-A-2008-127367.
5.00 parts of a salt represented by the formula (I1-e) and 30 parts of acetonitrile are charged, stirred at 40 ° C. for 30 minutes, 2.22 parts of a compound represented by the formula (I1-f) are charged, and 50 ° C. The solution containing the compound represented by the formula (I1-g) was obtained by stirring for 1 hour.

得られた式（Ｉ１−ｇ）で表される化合物を含む溶液に、式（Ｉ１−ｄ）で表される化合物３．７９部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム５０部及びイオン交換水２５部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭０．６０部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮した後、得られた濃縮物に、アセトニトリル３０部を添加して溶解し、濃縮し、酢酸エチル２０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−１）で表される塩６．６７部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ４８９．１

To the obtained solution containing the compound represented by the formula (I1-g), 3.79 parts of the compound represented by the formula (I1-d) was charged and stirred at 23 ° C. for 1 hour. Into the obtained reaction mass, 50 parts of chloroform and 25 parts of ion-exchanged water were added and stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 0.60 part of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. After the filtrate was concentrated, 30 parts of acetonitrile was added to the resulting concentrate to dissolve it, concentrated, 20 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 20 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 6.67 parts of the salt represented by the formula (I-1).
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 489.1

式（Ｉ７−ｅ）で表される塩を、特開２００８−１２７３６７号公報に記載された方法に準じて合成した。
式（Ｉ７−ｅ）で表される塩１．３７部及びアセトニトリル１０部を仕込み、４０℃で３０分間攪拌し、式（Ｉ７−ｆ）で表される化合物０．５６部を仕込み、５０℃で１時間攪拌することにより、式（Ｉ７−ｇ）で表される化合物を含む溶液を得た。 Example 2: Synthesis of a salt represented by the formula (I-7)

A salt represented by the formula (I7-e) was synthesized according to the method described in Japanese Patent Application Laid-Open No. 2008-127367.
1.37 parts of a salt represented by the formula (I7-e) and 10 parts of acetonitrile are charged, stirred at 40 ° C. for 30 minutes, 0.56 parts of a compound represented by the formula (I7-f) are charged, and 50 ° C. Was stirred for 1 hour to obtain a solution containing the compound represented by the formula (I7-g).

得られた式（Ｉ７−ｇ）で表される化合物を含む溶液に、式（Ｉ１−ｄ）で表される化合物０．９５部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム２０部及びイオン交換水１０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭０．３０部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮した後、得られた濃縮物に、アセトニトリル１０部を添加して溶解し、濃縮し、酢酸エチル１０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−７）で表される塩１．４２部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ３０５．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ４８９．１

To the obtained solution containing the compound represented by the formula (I7-g), 0.95 part of the compound represented by the formula (I1-d) was charged and stirred at 23 ° C. for 1 hour. Into the obtained reaction mass, 20 parts of chloroform and 10 parts of ion-exchanged water were charged, stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 0.30 part of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. After concentrating the filtrate, 10 parts of acetonitrile was added to the resulting concentrate to dissolve it, concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 1.42 parts of the salt represented by the formula (I-7).
MS (ESI (+) Spectrum): M ⁺ 305.1
MS (ESI (-) Spectrum): M ^- 489.1

式（Ｉ６７−ｅ）で表される塩を、特開２００８−１２７３６７号公報に記載された方法に準じて合成した。
式（Ｉ６７−ｅ）で表される塩１．６７部及びアセトニトリル１０部を仕込み、４０℃で３０分間攪拌し、式（Ｉ６７−ｆ）で表される化合物０．５６部を仕込み、５０℃で１時間攪拌することにより、式（Ｉ６７−ｇ）で表される化合物を含む溶液を得た。 Example 3: Synthesis of salt represented by formula (I-67)

A salt represented by the formula (I67-e) was synthesized according to the method described in Japanese Patent Application Laid-Open No. 2008-127367.
1.67 parts of a salt represented by the formula (I67-e) and 10 parts of acetonitrile are charged, stirred at 40 ° C. for 30 minutes, 0.56 parts of a compound represented by the formula (I67-f) are charged, and 50 ° C. Was stirred for 1 hour to obtain a solution containing the compound represented by formula (I67-g).

得られた式（Ｉ６７−ｇ）で表される化合物を含む溶液に、式（Ｉ１−ｄ）で表される化合物０．９５部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム２０部及びイオン交換水１０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭０．３０部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮した後、得られた濃縮物に、アセトニトリル１０部を添加して溶解し、濃縮し、酢酸エチル１０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−６７）で表される塩１．６８部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ３７５．２
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ４８９．１

To the obtained solution containing the compound represented by the formula (I67-g), 0.95 part of the compound represented by the formula (I1-d) was charged and stirred at 23 ° C. for 1 hour. Into the obtained reaction mass, 20 parts of chloroform and 10 parts of ion-exchanged water were charged, stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 0.30 part of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. After concentrating the filtrate, 10 parts of acetonitrile was added to the resulting concentrate to dissolve it, concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 1.68 parts of the salt represented by the formula (I-67).
MS (ESI (+) Spectrum): M ⁺ 375.2
MS (ESI (-) Spectrum): M ^- 489.1

Synthesis Example (Synthesis of Resin (A))
The compounds (monomers) used in the resin synthesis are shown below.
Hereinafter, these monomers are referred to as “monomer (A)” to “monomer (C)”.

Synthesis Example 1 [Synthesis of Resin A1]
29.32 parts of 1,4-dioxane was added to 11.18 parts of monomer (A), 14.60 parts of p-acetoxystyrene and 3.55 parts of monomer (B), and the mixture was heated to 87 ° C. To the obtained solution, 2.96 parts of azobisisobutyronitrile as an initiator was added, and kept at 87 ° C. for 6 hours. After cooling, the reaction solution was poured into a mixed solution of 304.97 parts of methanol and 76.24 parts of ion-exchanged water, and the polymer was precipitated and filtered. The obtained filtrate and 2.93 parts of 4-dimethylaminopyridine were added to the same amount of methanol as the obtained filtrate and heated under reflux for 15 hours. After cooling, the resulting reaction solution was neutralized by adding 2.09 parts of glacial acetic acid, and then poured into a large amount of water to cause precipitation. A polymer having a weight average molecular weight of about 3.5 × 10 ³ is purified by repeating the operation of filtering the precipitated polymer, dissolving it in acetone, pouring it into a large amount of water and precipitating it three times. 82 parts were obtained. This copolymer has structural units derived from the following monomers respectively derived from the monomer (A), p-hydroxystyrene, and the monomer (B), and this is designated as resin A1.

Synthesis Example 2 [Synthesis of Resin A2]
A monomer (A) 11.18 parts, p-acetoxystyrene 14.60 parts, monomer (B) 1.77 parts, monomer (C) 1.28 parts and 1,4-dioxane 28.83 parts are added to form a solution. The temperature was raised to 87 ° C. To the obtained solution, 2.96 parts of azobisisobutyronitrile as an initiator was added, and kept at 87 ° C. for 6 hours. After cooling, the reaction solution was poured into a mixed solution of 299.81 parts of methanol and 74.95 parts of ion-exchanged water, and the polymer was precipitated and filtered. The obtained filtrate and 2.88 parts of 4-dimethylaminopyridine were added to the same amount of methanol as the obtained filtrate and heated under reflux for 15 hours. After cooling, the resulting reaction solution was neutralized by adding 2.05 parts of glacial acetic acid, and then poured into a large amount of water to cause precipitation. A polymer having a weight average molecular weight of about 3.8 × 10 ³ is purified by repeating the operation of filtering the precipitated polymer, dissolving it in acetone, pouring it into a large amount of water and precipitating it three times. 91 parts were obtained. This copolymer has structural units derived from the following monomers derived from the monomer (A), p-hydroxystyrene, monomer (B) and monomer (C), respectively, and this is designated as resin A2. To do.

Examples 4 to 9 and Comparative Example 1
<Preparation of resist composition>
The components shown in Table 4 are mixed with the solvents shown below in the parts by mass shown in Table 4 and dissolved, and the resulting mixture is filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition. did.

<Resin>
A1: Resin A1 obtained in Synthesis Example 1
A2: Resin A2 obtained in Synthesis Example 2
<Acid generator>
I-1: salt represented by formula (I-1) obtained in Example 1 I-7: salt represented by formula (I-7) obtained in Example 2 I-67: Example Salt represented by formula (I-67) obtained in 3 B1-X:

＜溶剤＞
プロピレングリコールモノメチルエーテルアセテート ４００部
プロピレングリコールモノメチルエーテル １００部
γ−ブチロラクトン ５部 <Basic compound: Quencher>
C1:

<Solvent>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 100 parts γ-butyrolactone 5 parts

(Production and evaluation of resist patterns by electron beam irradiation)
A silicon wafer is treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds, and the above resist composition is spin-coated so that the film thickness after drying (pre-baking) is 0.06 μm. did. Then, it prebaked for 60 seconds on the direct hot plate at the temperature shown in the "PB" column of Table 4, and formed the composition layer. For each wafer on which the composition layer was formed in this way, an electron beam drawing machine ["HL-800D 50 keV" manufactured by Hitachi, Ltd. was used, and the exposure amount was changed stepwise via a photomask. The line and space pattern was exposed. A photomask used for forming a 70 nm line and space pattern was used.
After exposure, post-exposure baking is performed for 60 seconds on the hot plate at the temperature indicated in the “PEB” column of Table 4, and paddle development is further performed for 60 seconds with an aqueous 2.38 mass% tetramethylammonium hydroxide solution. Got a pattern.

<Evaluation of pattern collapse resistance (PCM)>
About the resist pattern formed with the exposure amount from which the line width of a resist pattern becomes the value of Table 4, the resist pattern loss | disappearance by fall or peeling was observed using the scanning electron microscope. When the disappearance of the resist pattern was not recognized, it was evaluated as “good”, and when it was recognized, it was evaluated as “poor”. The results are shown in Table 5.

  If a resist composition containing a resin having a structural unit derived from the compound of the present invention is used, a resist pattern having excellent pattern collapse resistance (PCM) can be produced.

Claims (8)

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.
L ¹ is a group represented by any one of formula (bL1-1) to formula (bL1-3) and formula (bL1-5) to formula (bL1-7).

[In Formula (bL1-1)-Formula (bL1-3), Formula (bL1-5)-Formula (bL1-7),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a C1-C13 divalent saturated hydrocarbon group. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b8 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 represents a single bond or a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^b10 represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
L ^b11 represents a single bond or a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b12 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b11 and L ^b12 is 14.
* In formula (bL1-1) to formula (bL1-3) and formula (bL1-5) to formula (bL1-7) represents a bond with C (Q ¹ ) (Q ² ). ]
L ³ -L ² is a group represented by the formula (bL2-1) or the formula (bL2-2).

[In Formula (bL2-1) and Formula (bL2-2),
L ^b13 and L ^b14 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b13 and L ^b14 is 14.
L ^b15 and L ^b17 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms. However , the upper limit of the total carbon number of L ^b15 , L ^b16 and L ^b17 is 12.
* In the formula (bL2-1) and the formula (bL2-2) represents a bond to the ring W ¹ . ]
Ring ^{W 1} represents an aromatic ring having 6 to 18 carbon atoms.
Ring W ² represents an aliphatic ring having 4 to 18 carbon atoms, a methylene group constituting the aliphatic ring may be replaced by an oxygen atom or a carbonyl group. However, at least one of the methylene groups contained in the aliphatic ring is replaced with a carbonyl group.
R ¹ represents a hydroxy group or an alkyl group having 1 to 6 carbon atoms.
R ² represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxycarbonyl group having 1 to 6 carbon atoms.
s represents the integer of 0-2. When s is 2, a plurality of R ¹ may be the same as or different from each other.
t represents an integer of 0-2. When t is 2, a plurality of R ² may be the same as or different from each other.
Z ⁺ represents an organic counter ion. ] Wherein ^{L 1} is salt according to claim 1, wherein a group represented by the formula (BL1-1). Wherein ^L 3 -L ² are salts of claim 1 or 2, wherein a group represented by the formula (BL2-1). The salt according to any one of claims 1 to 3, wherein Z ⁺ is an arylsulfonium cation.   The acid generator containing the salt in any one of Claims 1-4.   The acid generator according to claim 5 and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution, and can be dissolved in an alkaline aqueous solution by the action of an acid. Resist composition which is resin.   The resist composition according to claim 6, further comprising a basic compound. (1) A step of applying the resist composition according to claim 6 or 7 on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including: