JP6207065B2 - Salt, resist composition and method for producing resist pattern - Google Patents

Description

  The present invention relates to a resist composition, a method for producing a resist pattern, and a novel salt used in the resist composition.

Patent Document 1 discloses the following structural unit:
And the following structural units
A resin consisting of
The resist composition which consists of an acid generator represented by these and a solvent is described.

  Further, it is known that when a resist pattern is formed from a resist composition by photolithography, a positive resist pattern is obtained when developed with an alkaline developer, and a negative resist pattern is obtained when developed with an organic solvent ( Non-patent document 1).

JP 2008-309879 A

Published by Techno Times Inc. Monthly Display '11 June p. 31

  The negative resist pattern formed from the above-described resist compositions known in the past may not always be sufficiently satisfactory in resolution or CD uniformity (CDU).

The present invention includes the following inventions.
[1] A salt represented by the formula (I).
[L ¹ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Ring W ¹ represents an alicyclic hydrocarbon ring having 3 to 36 carbon atoms, and the methylene group constituting the ring may be substituted with an oxygen atom, a sulfur atom, a carbonyl group, or a sulfonyl group, The hydrogen atom contained in the ring may be substituted with a hydroxy group, a saturated hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
a1 and a2 each independently represent 0 or 1.
R ¹ and R ² each independently represents a saturated hydrocarbon group having 1 to 10 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, and R ¹ and R ² are These may be combined together to form a ring with — (CO) _a1 —O—C—O— (CO) _a2 —.
Z ⁺ represents an organic cation. ]
[2] A resist composition comprising a resin having an acid labile group, an acid generator, and a salt represented by the above formula (I).
[3] (1) A step of applying the resist composition of [2] 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:

  According to the resist composition of the present invention, a negative resist pattern having excellent resolution and CD uniformity (CDU) can be produced.

In the present specification, "(meth) acrylic monomer" means at least one monomer having a "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- " structure of To do. Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one of acrylate and methacrylate” and “at least one of acrylic acid and methacrylic acid”, respectively.

<Salt represented by formula (I)>
The salt of the present invention is a salt represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).
[L ¹ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Ring W ¹ represents an alicyclic hydrocarbon ring having 3 to 36 carbon atoms, and the methylene group constituting the ring may be substituted with an oxygen atom, a sulfur atom, a carbonyl group, or a sulfonyl group, The hydrogen atom contained in the ring may be substituted with a hydroxy group, a saturated hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
a1 and a2 each independently represent 0 or 1.
R ¹ and R ² each independently represents a saturated hydrocarbon group having 1 to 10 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, and R ¹ and R ² are These may be combined together to form a ring with — (CO) _a1 —O—C—O— (CO) _a2 —.
Z ⁺ represents an organic cation. ]

Examples of the divalent saturated hydrocarbon group constituting L ^1, a linear alkanediyl group, branched alkanediyl group, and a divalent alicyclic saturated hydrocarbon group having a monocyclic or polycyclic. Among 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;
Monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group, etc. Groups and the like.

The divalent alicyclic hydrocarbon group may be a group obtained by removing any two hydrogen atoms from the ring of the alicyclic hydrocarbon of ring W ¹ described later.

Examples of the group in which the methylene group in the divalent saturated hydrocarbon group of L ¹ is replaced by an oxygen atom or a carbonyl group are represented by any of the following formulas (b1-1) to (b1-7). Groups. The formula (b1-1) to the formula (b1-7) are described in accordance with the formula (I) on the left and right, and among the two bonds represented by *, the left bond is -CO. It is bonded to the carbon atom of-. The same applies to specific examples of the following formulas (b1-1) to (b1-7).

In formula (b1-1) to formula (b1-7),
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 divalent saturated hydrocarbon group having 1 to 13 carbon atoms. 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 12 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
L ^b11 and L ^b12 each independently represent a single bond or a 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.

The group in which the methylene group in the saturated hydrocarbon group of L ¹ is replaced with an oxygen atom or a carbonyl group is preferably a group represented by any one of formulas (b1-1) to (b1-5), and more preferably Is a group represented by any one of formulas (b1-1) to (b1-4), more preferably a group represented by formula (b1-1) or formula (b1-3), Preferably, it is a divalent group represented by the formula (b1-1). Among them, preferably, L ^b2 in the formula (b1-1) is a single bond or a saturated hydrocarbon group having 1 to 6 carbon atoms, that is, * —CO—O— (CH ₂ ) _t — (t is 0 to 6). Represents an integer, * represents a bond to —CO—, and more preferably a divalent group represented by the formula (b1-1) in which L ^b2 is a single bond or a methylene group; Preferably, it is a divalent group represented by the formula (b1-1) in which L ^b2 is a single bond, that is, * —CO—O—.

Examples of the divalent group represented by the formula (b1-1) include the following.

Examples of the divalent group represented by the formula (b1-2) include the following.
Examples of the divalent group represented by the formula (b1-3) include the following.
Examples of the divalent group represented by the formula (b1-4) include the following.
Examples of the divalent group represented by the formula (b1-5) include the following.
Examples of the divalent group represented by the formula (b1-6) include the following.
Examples of the divalent group represented by the formula (b1-7) include the following.

L ¹ is preferably a single bond.

The alicyclic hydrocarbon ring having 3 to 36 carbon atoms in the ring W ¹ may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon ring include a cyclopentane ring, Examples include cycloalkane rings such as cyclohexane ring, cycloheptane ring, and cyclooctane ring.
Examples of the polycyclic alicyclic hydrocarbon ring include a decahydronaphthalene ring, an adamantane ring, a norbornane ring, and a ring represented by the following formula.
The hydrogen atom contained in the alicyclic hydrocarbon ring is substituted with a hydroxy group, a saturated hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms. It may be. When the alicyclic hydrocarbon ring has a substituent, the number of substituents can be any number of 1 or more. For example, examples of the alicyclic hydrocarbon ring substituted with a saturated hydrocarbon group include methylcyclohexane, dimethylcyclohexane, and methylnorbornane ring.

Saturated hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and other alkyl groups; cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Cycloalkyl groups such as: a group in which an alkyl group such as a methylcyclohexyl group or a dimethylcyclohexyl group and a cycloalkyl group are combined.
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-pentyloxy group, and an n-hexyloxy group. Can be mentioned.
Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, anthryl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group; tolyl group, xylyl group, cumenyl group, mesityl group. , Aryl groups such as biphenylyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl, and the like.

Among them, ring W ¹ is ring, ring of the formula (IIa1-2) represented by ring or expressions (IIa1-3) preferably of the formula (IIa1-1), more preferably, It is a ring represented by the formula (IIa1-1).
[In Formula (IIa1-1), Formula (IIa1-2) and Formula (IIa1-3),
The methylene group contained in the ring may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the ring is a hydroxy group, a saturated hydrocarbon group having 1 to 12 carbon atoms, or a carbon number. It may be substituted with an alkoxy group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]

  a1 and a2 each independently represent 0 or 1, preferably both are the same numerical value, and more preferably both are 0.

Examples of the saturated hydrocarbon group for R ¹ and R ² include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group; a cyclopentyl group, a cyclohexyl group, a cyclo Examples include a cycloalkyl group such as a heptyl group and a cyclooctyl group; a group in which an alkyl group such as a methylcyclohexyl group and a dimethylcyclohexyl group and a cycloalkyl group are combined.
The saturated hydrocarbon group in which the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom is, for example, a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, 2 , 2,2-trifluoroethyl group, perfluoroethyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1 -(Trifluoromethyl) -1,2,2,2-tetrafluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexa Fluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-tri Fluoroethyl group, 2- (perfluoropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4 , 4,5,5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group 1,1,2,2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6- Examples thereof include fluorinated alkyl groups such as dodecafluorohexyl group, perfluoropentylmethyl group, and perfluorohexyl group. Of these, a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, and the like are preferable.

The ring formed with — (CO) _a1 —O—C—O— (CO) _a2 — in which R ¹ and R ² are joined together is a single ring as long as it includes —O—C—O—. Any ring of formula, polycyclic, saturated and unsaturated may be used, and examples thereof include 5 to 15 membered rings, preferably 5 to 13 membered rings, and more preferably 5 to 9 membered rings.
Among them, preferably, R ¹ and R ² are together with a fluorinated alkyl group or — (CO) _a1 —O—C—O— (CO) _a2 —, in which R ¹ and R ² are bonded together. A ring to be formed, more preferably a fluorinated alkyl group or a ring in which R ¹ and R ² are combined to include —O—C—O—, and more preferably a fluorinated alkyl group or R ^1. And R ² together forms a ring represented by the formula (z).
In the formula (z), R ^f1 and R ^f2 each independently represent a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms, and * represents a bond.
s represents an integer of 1 to 10, and when s is 2 or more, the plurality of R ^f1 are the same or different, and the plurality of R ^f2 are the same or different.
Of these, both R ^f1 and R ^f2 are preferably fluorine atoms.
s is preferably an integer of 1 to 8, more preferably an integer of 1 to 6, further preferably an integer of 1 to 4, and particularly preferably 1 or 2. That is, the ring represented by the formula (z) is particularly preferably the following ring.

Examples of the salt (I) include the following salts (I-1-1) to (I-1-17).

Examples of Z ⁺ include organic onium cations such as organic sulfonium cations, organic iodonium cations, organic ammonium cations, benzothiazolium cations, and organic phosphonium cations. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, an arylsulfonium cation is more preferable, and a cation represented by any one of the formulas (b2-1) to (b2-4) [hereinafter, depending on the formula number Sometimes referred to as “cation (b2-1)”. ] Is more preferable.

In formula (b2-1) to formula (b2-4),
R ^{b4 to} R ^b6 each independently represents 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 36 carbon atoms, or R ^b4 And R ^b5 together form a ring containing a sulfur atom. The hydrogen atom contained in the alkyl group is substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 18 carbon atoms, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group. The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group or an alkoxy group having 1 to 12 carbon atoms.

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. When m2 is 2 or more, the plurality of R ^b7 are the same or different from each other, and when n2 is 2 or more, the plurality of R ^b8 are the same or different from each other.
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, or R ^b9 and R ^b10 are A 3-membered to 12-membered ring (preferably a 3-membered to 7-membered ring) is formed together with the sulfur atom to be bonded. One or more methylene groups constituting the ring may be replaced with an oxygen atom, -SO- or a carbonyl group.
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 ^b12 represents an alkyl group having 1 to 12 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 an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group is an alkoxy group having 1 to 12 carbon atoms. Alternatively, it may be substituted with an alkylcarbonyloxy group having 1 to 12 carbon atoms.
R ^b11 and R ^b12 may form a 3- to 12-membered ring (preferably a 3- to 7-membered ring) together with —CH—CO— to which they are bonded. One or more methylene groups constituting the ring may be replaced with an oxygen atom, -SO- 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 ^b13 represents —S— or —O—.
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 are the same or different from each other. When p2 is 2 or more, the plurality of R ^b14 are the same or different from each other. When q2 is 2 or more, the plurality of R ^b15 are the same. Alternatively, when r2 is 2 or more, a plurality of R ^b16 are the same or different from each other, when s2 is 2 or more, a plurality of R ^b17 are the same or different from each other, and when t2 is 2 or more, a plurality of R ^{b16 b18} are the same or different from each other.

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 and 2-ethylhexyl group. Can be mentioned. In particular, the alkyl group of R ^{b9 to} R ^b12 preferably has 1 to 12 carbon atoms.
Examples of the alkyl group in which a hydrogen atom is substituted with an alicyclic hydrocarbon group include a 1- (adamantan-1-yl) alkane-1-yl group.

The alicyclic hydrocarbon group may be monocyclic or polycyclic, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an alkyl group. In this case, the carbon number of the alicyclic hydrocarbon group is 20 or less including the carbon number of the alkyl group. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups.
In particular, the alicyclic hydrocarbon group of R ^{b9 to} R ^b11 preferably has 4 to 12 carbon atoms.
Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an alkyl group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-alkyladamantan-2-yl group, a methylnorbornyl group, and an isobornyl group. Can be mentioned.

  Examples of the aromatic hydrocarbon group include phenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-adamantyl group. Substituted or unsubstituted phenyl groups such as phenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group; biphenylyl group, naphthyl group, phenanthryl group and the like.

  As an aromatic hydrocarbon group by which the hydrogen atom was substituted by the alkoxy group, 4-methoxyphenyl group etc. are mentioned, for example.

Examples of the alkyl group in which a hydrogen atom is substituted with an aromatic hydrocarbon group, that is, an aralkyl group, include a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group.
In addition, when an alkyl group or an alicyclic hydrocarbon group is contained in an aromatic hydrocarbon group, a C1-C12 alkyl group and a C3-C18 alicyclic hydrocarbon group are preferable.

Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
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.

The ring containing a sulfur atom which may be formed by combining R ^b4 and R ^b5 is 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 18 carbon atoms is more preferable.

Examples of the ring formed together with the sulfur atom to which R ^b9 and R ^b10 are bonded include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium. A ring etc. are mentioned.
Examples of the ring formed with —CH—CO— in which R ^b11 and R ^b12 are bonded include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

Among the cation (b2-1) to cation (b2-4), the cation (b2-1) is preferable, more preferably a cation represented by the formula (b2-1-1) (hereinafter referred to as “cation ( more preferably triphenylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 0), diphenyltolylsulfonium cation (formula ( b2-1-1), v2 = w2 = 0, x2 = 1, R ^b21 is a methyl group) or a tolylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 1 and R ^b19 , R ^b20 and R ^b21 are all methyl groups).

In formula (b2-1-1),
R ^b19 , R ^b20 and R ^b21 each independently represent a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or 3 to 18 carbon atoms. Represents an alicyclic hydrocarbon group. It is also possible that two selected from R ^b19 to R ^b21 together form a ring containing a sulfur atom.

v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, the plurality of R ^b19 are the same or different from each other. When w2 is 2 or more, the plurality of R ^b20 are the same or different from each other. When x2 is 2 or more, the plurality of R ^b21 are the same. Or different.

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.

  Specific examples of the cation represented by the formula (b2-1-1) include cations described in JP 2010-204646 A.

Examples of the cation (b2-1-1) 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 the above-mentioned anion and organic cation. The above-mentioned anions and cations can be arbitrarily combined. These combinations include an anion represented by formula (I-1-1) to formula (I-1-17), formula (b2-c-1), formula (b2-c-10), formula (b2- The combination with the organic cation shown by c-13), Formula (b2-c-14), Formula (b2-c-141)-Formula (b2-c-144) is preferable.

Among these, as the salt (I), the following salts (I-1) to (I-26) are preferable.

The salt (I) can be produced, for example, by the following method. In the following description, each symbol represents the same meaning as described above unless otherwise specified.
First, a compound represented by the formula (I-r1), a compound represented by the formula (Ir2), and a compound represented by the formula (Ir3) are dissolved in an organic solvent, and in the presence of an acid catalyst. By reacting, a compound represented by the formula (I-r4) can be obtained.
Examples of the organic solvent include chloroform, dichloroethane, dichloromethane, tetrahydrofuran, acetonitrile, benzene, toluene, monochlorobenzene, and the like.
Examples of the acid catalyst include sulfuric acid, hydrochloric acid, toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, and pyridinium salts thereof.
[Wherein R ³ represents a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms. ]
Of the compounds represented by the formula (I-r4), when R ³ is a saturated hydrocarbon group having 1 to 10 carbon atoms, the ester is hydrolyzed under basic conditions such as sodium hydroxide or potassium hydroxide. The compound represented by the formula (I-r5) can be obtained.
Next, the salt represented by the formula (Ir6) can be obtained by reacting the compound represented by the formula (Ir5) with a metal salt or a metal oxide.
[Wherein, M _r ⁺ represents a monovalent metal cation. ]
Examples of M _r ⁺ include Ag ⁺ , Na ⁺ , K ^{+ and the} like. By using silver oxide (I), sodium hydroxide or potassium hydroxide as the metal salt or metal oxide, the corresponding silver salt, salt represented by the formula (Ir6) as sodium salt or potassium salt is obtained. can get.
The salt (I) can be produced by reacting the salt represented by the formula (Ir6) produced as described above with the salt represented by the formula (Ir7).
[Wherein, X ⁻ represents a halogen atom. ]

  By using the salt (I) in the resist composition, the resolution and / or CDU of the resist pattern formed by the resist composition can be improved.

<Resist composition>
The resist composition of the present invention comprises:
A resin having an acid labile group (hereinafter sometimes referred to as “resin (A)”),
It contains an acid generator (hereinafter sometimes referred to as “acid generator (B)”) and a salt represented by the formula (I) (hereinafter also referred to as “salt (I)”).
The resist composition of the present invention preferably further contains a solvent (E).
The resist composition of the present invention may further contain a basic compound (C).

<Resin (A)>
The resin (A) is usually a resin containing a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a1)”). The structural unit (a1) is derived from a monomer having an acid labile group (hereinafter sometimes referred to as “monomer (a1)”).

<Acid labile group>
The “acid labile group” means a group having a leaving group and forming a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group by contact with an acid. Examples of the acid labile group include a group represented by the formula (1) and a group represented by the formula (2).

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

[In Formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group 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 methylene group contained in the hydrocarbon group and the divalent hydrocarbon group is An oxygen atom or a sulfur atom may be substituted. ]

^Examples of the alkyl group represented by 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.

The alicyclic hydrocarbon group for R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bond). The alicyclic hydrocarbon group of R ^{a1 to} R ^a3 preferably has 3 to 16 carbon atoms.

  Examples of the group obtained by combining an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, and a methylnorbornyl group. A group in which an alkyl group and an alicyclic hydrocarbon group are combined preferably has 20 or less carbon atoms.

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 hydrocarbon group include the following groups. The divalent hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

Examples of the group represented by the formula (1) include a 1,1-dialkylalkoxycarbonyl group (in the formula (1), R ^{a1 to} R ^a3 are alkyl groups, preferably a tert-butoxycarbonyl group), 2-alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom form an adamantyl group, and R ^a3 is an alkyl group) and 1- (adamantane-1- Yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

Examples of the hydrocarbon group for R ^{a1 ′ to} R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.

Examples of the divalent hydrocarbon group formed by combining R ^{a2 ′} and R ^{a3 ′} include groups in which one hydrogen atom has been removed from the hydrocarbon groups of R ^{a1 ′ to} R ^{a3 ′} .

In Formula (2), it is preferable that 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. * Represents a bond.

  The monomer (a1) is preferably a monomer having an acid labile group and an ethylenically unsaturated bond, more preferably a (meth) acrylic monomer having an acid labile group.

  Among the (meth) acrylic monomers having an acid labile group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferable. If the resin (A) having a structural unit derived from the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in the resist composition, the resolution of the resist pattern can be improved.

As a structural unit derived from a (meth) acrylic monomer having a group represented by formula (1), preferably a structural unit represented by formula (a1-1) or a structure represented by formula (a1-2) Units are listed. These may be used alone or in combination of two or more. In this specification, the structural unit represented by the formula (a1-1) and the structural unit represented by the formula (a1-2) are represented by the structural unit (a1-1) and the structural unit (a1-2), respectively. The monomer that derives the structural unit (a1-1) and the monomer that derives the structural unit (a1-2) may be referred to as a monomer (a1-1) and a monomer (a1-2), respectively.
Especially, it is preferable that resin has a structural unit (a1-1).

[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 18 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—, more preferably —O—. k1 is preferably an integer of 1 to 4, more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
Examples of the alkyl group of R ^a6 and R ^a7 , the alicyclic hydrocarbon group, and the group obtained by combining these include the same groups as those described for R ^{a1 to} R ^a3 in formula (1).
The alkyl group for R ^a6 and R ^a7 preferably has 6 or less carbon atoms.
The alicyclic hydrocarbon group of R ^a6 and R ^a7 preferably has 8 or less carbon atoms, more preferably 6 or less.
The group combining the alkyl group and the alicyclic hydrocarbon group preferably has a total carbon number of 18 or less, combining the alkyl group and the alicyclic hydrocarbon group. Examples of such a group include a methylcyclohexyl group, a dimethylcyclohexyl group, and a methylnorbornyl group.
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.

As a monomer (a1-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, a monomer represented by any one of formula (a1-1-1) to formula (a1-1-8) is preferable, and any one of formula (a1-1-1) to formula (a1-1-4) is preferable. The monomer represented by is more preferable.

Examples of the monomer (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, and 1-ethylcycloheptan-1-yl (meth). Examples include acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, and 1-isopropylcyclopentan-1-yl (meth) acrylate. Monomers represented by the formula (a1-2-1) to the formula (a1-2-12) are preferred, and the formula (a1-2-3) to the formula (a1-2-4) or the formula (a1-2-9) The monomer represented by formula (a1-2-10) is more preferable, and the monomer represented by formula (a1-2-3) or formula (a1-2-9) is more preferable.

  When the resin (A) contains the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is usually 10 to 95 mol with respect to all the structural units of the resin (A). %, Preferably 15 to 90 mol%, more preferably 20 to 85 mol%.

Examples of the structural unit (a1) having a group represented by the formula (1) also include a structural unit represented by the formula (a1-3). In this specification, the structural unit represented by the formula (a1-3) may be referred to as the structural unit (a1-3) and the monomer that derives the structural unit (a1-3) may be referred to as a monomer (a1-3). is there.
In formula (a1-3),
R ^a9 represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have a hydroxy group, a carboxy group, a cyano group, a hydrogen atom, or —COOR ^a13 .
R ^a13 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group in which these are combined, and the aliphatic hydrocarbon group and the alicyclic carbon group. The hydrogen atom contained in the hydrogen group may be substituted with a hydroxy group, and the methylene group contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. Good.
R ^a10, R ^a11 and R ^a12 are each independently an alkyl group having 1 to 8 carbon atoms, or an alicyclic hydrocarbon group or a group obtained by combining these C3-20, R ^a10 and R ^a11 are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms.

Here, examples of —COOR ^a13 in R ^a9 include a group in which a carbonyl group is bonded to an alkoxy group such as a methoxycarbonyl group and an ethoxycarbonyl group.

Examples of the aliphatic hydrocarbon group which may have a hydroxy group for R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group and a 2-hydroxyethyl group.
^Examples of the group ^{consisting of} an aliphatic hydrocarbon group represented by R ^a13 , an alicyclic hydrocarbon group, and an aliphatic hydrocarbon group having 1 to 8 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms include, for example, methyl Group, ethyl group, propyl group, cyclopentyl group, cyclopropyl group, adamantyl group, adamantylmethyl group, 1-adamantyl-1-methylethyl group, 2-oxo-oxolan-3-yl group and 2-oxo-oxolane-4 -An yl group etc. are mentioned.
^{Examples of} R ^{a10 to} R ^a12 include the same groups as R ^{a1 to} R ^a3 in formula (1).
As —C (R ^a10 ) (R ^a11 ) (R ^a12 ) when R ^a10 and R ^a11 are bonded to each other to form a divalent hydrocarbon group, the following groups are preferred.

  Specific examples of the monomer (a1-3) include 5-norbornene-2-carboxylic acid-tert-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, and 5-norbornene-2-carboxylic acid. Acid 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-oxo (Cyclohexyl) ethyl and 1- (1-adamantyl) -1-methyl 5-norbornene-2-carboxylate Chill, or the like.

  Since the resin (A) containing the structural unit (a1-3) includes a sterically bulky structural unit, the resist composition of the present invention containing such a resin (A) is more expensive. A resist pattern can be obtained with resolution. Further, since a rigid norbornane ring is introduced into the main chain, the resulting resist pattern tends to be excellent in dry etching resistance.

  When the resin (A) includes the structural unit (a1-3), the content is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, based on all the structural units of the resin (A). 20-85 mol% is more preferable.

As the structural unit (a1) having a group represented by the formula (2), a structural unit represented by the formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”). Can be mentioned.
[In the formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 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.
la represents an integer of 0 to 4. When la is 2 or more, the plurality of R ^a33 are the same or different from each other.
R ^a34, R ^a35 and R ^a36 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a34 may represent a hydrocarbon group having 1 to 20 carbon atoms, R ^a35 and R ^a36 Are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and the methylene group contained in the hydrocarbon group and the divalent hydrocarbon group may be replaced with an oxygen atom or a sulfur atom. . ]

^Examples of the alkyl group for R ^a32 and R ^a33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, and a hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
Examples of the halogen atom for R ^a32 and R ^a33 include a fluorine atom, a chlorine atom and a bromine atom.
^Examples of the acyl group for R ^a33 include an acetyl group, a propionyl group, a butyryl group, and an isobutyryl group.
^Examples of the acyloxy group for R ^a33 include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.

In formula (a1-4), R ^a32 is preferably a hydrogen atom.
R ^a33 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and further preferably a methoxy group.
la is preferably 0 or 1, more preferably 0.
R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably a hydrocarbon group having 1 to 12 carbon atoms, more preferably a methyl group or an ethyl group.
The hydrocarbon group for R ^a36 is preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof. More preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic aliphatic hydrocarbon group having 3 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. The alkyl group and the alicyclic hydrocarbon group are preferably unsubstituted. When the aromatic hydrocarbon group has a substituent, the substituent is preferably an aryloxy group having 6 to 10 carbon atoms.
Examples of the aryloxy group include a phenyloxy group and a naphthyloxy group.

As a monomer which introduce | transduces structural unit (a1-4), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, monomers represented by formula (a1-4-1) to formula (a1-4-7) are preferable, and monomers represented by formula (a1-4-1) to formula (a1-4-5) are preferable. Is more preferable.

  When resin (A) has a structural unit (a1-4), the content rate is preferable with respect to all the structural units of resin (A), and 10-95 mol% is preferable, and 15-90 mol% is more preferable. 20 to 85 mol% is more preferable.

Examples of the structural unit (a1) include a structural unit represented by the formula (a1-5) (hereinafter may be referred to as “structural unit (a1-5)”).
In formula (a1-5),
R ³¹ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ^a1 represents a single bond or * — [CH ₂ ] _{k1 ′} —CO—L ^{a4 ′} —. Here, k1 ′ 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 —O—.
One of L ^{a2 ′} and L ^{a3 ′} is preferably —O— and the other is —S—.
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—.

As a monomer (a1-5), the following monomers are mentioned, for example.

  When resin (A) has a structural unit (a1-5), the content rate is preferable 1-50 mol% with respect to all the structural units of resin (A), and 3-45 mol% is more preferable. 5 to 40 mol% is more preferable.

<Structural unit without acid labile group>
The resin (A) may have a structural unit having no acid labile group (hereinafter sometimes referred to as “structural unit (s)”). The structural unit (s) is derived from a monomer having no acid labile group (hereinafter sometimes referred to as “monomer (s)”).
The monomer (s) is preferably a monomer having a hydroxy group or a lactone ring. A structural unit derived from an acid-stable monomer having a hydroxy group (hereinafter sometimes referred to as “structural unit (a2)”) and / or a structural unit derived from an acid-stable monomer containing a lactone ring (hereinafter referred to as “structural unit (a3)”) If the resin having the above is used for preparing the resist composition, the resolution of the resist pattern and the adhesion to the substrate can be improved.

<Structural unit (a2)>
The hydroxy group contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
A structure having a phenolic hydroxy group as the structural unit (a2) when the resist composition of the present invention is applied to KrF excimer laser exposure (248 nm), exposure to high energy rays such as an electron beam or EUV (extreme ultraviolet light) It is preferable to use the unit (a2). When applied to ArF excimer laser exposure (193 nm) or the like, the structural unit (a2) having an alcoholic hydroxy group is preferable as the structural unit (a2). As the structural unit (a2), one type may be contained alone, or two or more types may be used in combination.

Examples of the structural unit (a2) having a phenolic hydroxy group include a structural unit represented by the formula (a2-0) (hereinafter sometimes referred to as “structural unit (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 an integer of 2 or more, the plurality of R ^a31 may be the same as or different from each other. ]

^Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom for R ^{a30 include} the same groups as R ^{a31 in} formula (a1-5). Among them, R ^a30 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
The alkoxy group of R ^a31 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and further preferably a methoxy group.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.

Examples of the monomer that derives the structural unit (a2-0) include monomers described in JP 2010-204634 A.
Among them, the structural unit (a2-0) is represented by formula (a2-0-1), formula (a2-0-2), formula (a2-0-3), and formula (a2-0-4), respectively. What is represented is preferable, and what is represented by a formula (a2-0-1) or a formula (a2-0-2) is more preferable.

  Resin (A) containing the structural unit (a2-0) is polymerized using a monomer in which the phenolic hydroxy group of the monomer that derives the structural unit (a2-0) is protected with a protective group such as an acetyl group. It can be produced by carrying out a reaction and then deprotecting. However, when the deprotection treatment is performed, the acid labile group of the structural unit (a1) needs to be not significantly impaired.

  When the resin (A) has the structural unit (a2-0), the content is preferably from 5 to 95 mol%, more preferably from 10 to 80 mol%, based on all the structural units of the resin (A). 15-80 mol% is more preferable.

As the structural unit (a2) having an alcoholic hydroxy group, a structural unit represented by the formula (a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”) is preferable.
In 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 the formula (a2-1), L ^a3 is preferably, -O -, - O- (CH 2) f1 -CO-O- and is (wherein f1 is an integer from 1 to 4), more preferably Is —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.

Examples of the monomer that derives the structural unit (a2-1) include monomers described in JP 2010-204646 A. 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 resin (A) contains a structural unit (a2-1), the content rate is 1-45 mol% normally with respect to all the structural units of resin (A), Preferably it is 1-40 mol%. More preferably, it is 1-35 mol%, More preferably, it is 2-20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be, for example, a single ring such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a bridged ring including such a lactone ring structure. Good. Among these lactone rings, a γ-butyrolactone ring or a bridged ring containing a γ-butyrolactone ring structure is preferable.

  The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), the formula (a3-3), or the formula (a3-4). These 1 type may be contained independently and 2 or more types may be contained.

[In the formula (a3-1),
L ^a4 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon 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.
In formula (a3-2),
L ^a5 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a19 represents a hydrogen atom or a methyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 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.
In formula (a3-3),
L ^a6 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
r1 represents an integer of 0 to 3. When r1 is 2 or more, the plurality of R ^a23 are the same or different from each other.
In formula (a3-4),
R ^a24 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^a7 is a single bond, ^* —L ^a8 —O—, ^* —L ^a8 —CO—O—, ^* —L ^a8 —CO—O—L ^a9 —CO—O— or ^* —L ^a8 —O—CO —L ^a9 —O— is represented.
* Represents a bond with -O-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms. ]

Examples of the halogen atom for R ^a24 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
^Examples of the alkyl group for R ^a24 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. , Preferably it is a C1-C4 alkyl group, More preferably, it is a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom of R ^a24 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluoro group. Examples include a hexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

^Examples of the alkanediyl group represented by L ^a8 and L ^a9 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, and a pentane-1,5. -Diyl group and hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, 4-diyl group, 2-methylbutane-1,4-diyl group, etc. are mentioned.

In the formula (a3-1) to the formula (a3-3), L ^{a4 to} L ^a6 are each independently preferably an oxygen atom or * —O— (CH ₂ ) in which k3 is an integer of 1 to 4. A group represented by _{k 3} —CO—O—, more preferably an oxygen atom and * —O—CH ₂ —CO—O—, still more preferably an oxygen atom.
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 an integer of 0-2.

In formula (a3-4),
R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group.
L ^a7 is preferably a single bond or ^* -L ^a8 —CO—O—, and more preferably a single bond, —CH ₂ —CO—O— or —C ₂ H ₄ —CO—O—. .

  Examples of the monomer for deriving the structural unit (a3) include monomers described in JP2010-204646A and monomers described in JP2000-122294A. For example, Formula (a3-1-1) to Formula (a3-1-6), Formula (a3-2-1) to Formula (a3-2-4), Formula (a3-3-1) to Formula (a3) -3-4) and a monomer represented by any one of formulas (a3-4-1) to (a3-4-6). Among these, a monomer represented by any one of formula (a3-1-1) to formula (a3-1-2) and formula (a3-2-3) to formula (a3-2-4) is preferable. A monomer represented by (a3-1-1) or formula (a3-2-3) is more preferable.

In Formula (a3-4-1) to Formula (a3-4-6), a structural unit in which a methyl group corresponding to R ^a24 is replaced with a hydrogen atom can also be given as a specific example of structural unit (a3-4). it can.

When the resin (A) includes the structural unit (a3), the content is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on all the structural units of the resin (A). More preferably, it is 10-60 mol%.
Moreover, the content rate of a structural unit (a3-1), a structural unit (a3-2), a structural unit (a3-3), and a structural unit (a3-4) is respectively with respect to all the structural units of resin (A). 5 to 60 mol% is preferable, 5 to 50 mol% is more preferable, and 10 to 50 mol% is more preferable.

<Other structural units (s)>
Examples of the structural unit (s) include a structural unit having a halogen atom in addition to the structural unit (a2) and the structural unit (a3) (hereinafter sometimes referred to as “structural unit (a4)”).

As a structural unit (a4), the structural unit represented by a formula (a4-1) is mentioned, for example.
[In the formula (a4-1),
R ^a41 represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
A ^a41 is an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a formula (a-g1).
[In the formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent an ^optionally substituted aliphatic hydrocarbon group having 1 to 5 carbon atoms.
A ^a43 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent or a single bond.
X ^a41 and X ^a42 each independently represent —O—, —CO—, ^—CO —O— or —O—CO—.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 6 or less. ]
Represents a group represented by
R ^a42 represents an ^optionally substituted hydrocarbon group having 1 to 20 carbon atoms, and the methylene group contained in the hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
However, at least one of A ^a41 and R ^a42 is a group having a halogen atom. ]

R ^a41 includes the same group as R ^a24 in formula (a3-4). Of these, R ^a41 is preferably a hydrogen atom or a methyl group.
^Examples of the hydrocarbon group for R ^a42 include chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups in which these are combined. The aliphatic hydrocarbon group may have a carbon-carbon unsaturated bond, but is preferably an aliphatic saturated hydrocarbon group. Examples of the aliphatic saturated hydrocarbon group include linear or branched alkyl groups, alicyclic hydrocarbon groups, and groups obtained by combining alkyl groups and alicyclic hydrocarbon groups.
Examples of chain aliphatic hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, hexadecyl, pentadecyl, and hexyl. A decyl group, a heptadecyl group, an octadecyl group, etc. are mentioned. Examples of the cyclic aliphatic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups (* represents a bond).
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a biphenylyl group, a phenanthryl group, and a fluorenyl group.
Examples of the group in which the methylene group contained in the hydrocarbon group is replaced with an oxygen atom or a carbonyl group include groups represented by the formula (a-g3) described later.

^As the hydrocarbon group for R ^a42 , a chain and cyclic aliphatic hydrocarbon group and a group in which these are combined are preferred, and a chain and cyclic aliphatic saturated hydrocarbon group and a group in which these are combined Is more preferable.
R ^a42 is preferably an aliphatic hydrocarbon group having a halogen atom or an aliphatic hydrocarbon group having a group represented by the formula (a-g3).
[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents a C ^3-17 aliphatic hydrocarbon group having at least one halogen atom. ]

  As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, Preferably it is a fluorine atom.

When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3), including the carbon number contained in the group represented by the formula (a-g3), the aliphatic hydrocarbon The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When it has a group represented by the formula (a-g3) as a substituent, the number is preferably 1.

The aliphatic hydrocarbon having a group represented by the formula (a-g3) is more preferably a group represented by the formula (a-g2).
[In the formula (a-g2),
A ^a46 represents an aliphatic hydrocarbon group having 3 to 15 carbon atoms which may have a halogen atom.
X ^a44 represents a carbonyloxy group or an oxycarbonyl group.
A ^a47 represents an aliphatic hydrocarbon group having 3 to 15 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of A ^a46 , A ^a47, and X ^a44 is 18 or less, and at least one of A ^a46 and A ^a47 has at least one halogen atom. ]

When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and still more preferably a carbon number. It is a 1-6 perfluoroalkyl group, Most preferably, it is a C1-C3 perfluoroalkyl group. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.

1-6 are preferable and, as for carbon number of the aliphatic hydrocarbon group of ^Aa46 , 1-3 are more preferable.
4-15 are preferable, as for carbon number of the aliphatic hydrocarbon group of ^Aa47 , 5-12 are more preferable, and ^Aa47 has a cyclohexyl group or an adamantyl group further more preferable.

Preferred partial structures represented by * -A ^a46 -X ^a44 -A ^a47 (* is a bond to a carbonyl group) include the following structures.

^As the alkanediyl group of ^Aa41 , a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group , A straight-chain alkanediyl group such as hexane-1,6-diyl group; 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2 -Branched alkanediyl groups such as a diyl group, 1-methylbutane-1,4-diyl group, 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group of A ^a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and still more preferably an ethylene group.

In the group represented by the formula (a-g1) of A ^a41 (hereinafter sometimes referred to as “group (a-g1)”), A ^a44 is ^bonded to —O—CO—R ^a42 .
As the aliphatic hydrocarbon group for A ^a42 , A ^a43 and A ^{a44 in} the group (a-g1), a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane- Examples include 1,4-diyl group, 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group and the like. Examples of these substituents include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably 0.

^Examples of the group (a-g1) in which s is 0 and X ^a42 is an oxygen atom include the following groups. In the following examples, among the two bonds represented by *, * on the right side is a bond with —O—CO—R ^a42 .

Examples of the group (a-g1) in which s is 0 and X ^a42 is a carbonyl group include the following groups.

Examples of the group (a-g1) in which s is 0 and X ^a42 is a carbonyloxy group include the following groups.

Examples of the group (a-g1) in which s is 0 and X ^a42 is an oxycarbonyl group include the following groups.

As the structural unit represented by the formula (a4-1), a structural unit represented by the formula (a4-2) or the formula (a4-3) is preferable.
[In the formula (a4-2),
R ^f1 represents a hydrogen atom or a methyl group.
A ^f1 represents an alkanediyl group having 1 to 6 carbon atoms.
R ^f2 represents a C 1-10 hydrocarbon group having a fluorine atom. ]

As the alkanediyl group of A ^f1 , a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group , A straight-chain alkanediyl group such as hexane-1,6-diyl group; 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2 -Branched alkanediyl groups such as a diyl group, 1-methylbutane-1,4-diyl group, 2-methylbutane-1,4-diyl group.

The hydrocarbon group for R ^f2 includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and the aliphatic hydrocarbon group includes a chain type, a cyclic group, and a combination thereof. As the aliphatic hydrocarbon group, an alkyl group and an alicyclic hydrocarbon group are preferable.
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 and 2-ethylhexyl group. .
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a methyl group. Examples thereof include cycloalkyl groups such as cyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group, and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, 2-alkyladamantan-2-yl group, 1- (adamantan-1-yl) alkane-1-yl group, and norbornyl. Group, methylnorbornyl group and isobornyl group.

Examples of the hydrocarbon group having a fluorine atom for R ^f2 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Specifically, as the alkyl group having a fluorine atom, a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, Perfluoroethyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2 , 2,2-tetrafluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexafluorobutyl group, 1,1,2, 2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, 2- (perfluoro (Ropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,4,5,5- Decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2, 2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl group, perfluoropentyl Examples thereof include fluorinated alkyl groups such as a methyl group and a perfluorohexyl group.
Examples of the alicyclic hydrocarbon group having a fluorine atom include fluorinated cycloalkyl groups such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

In Formula (a4-2), as A ^f1 , an alkanediyl group having 2 to 4 carbon atoms is preferable, and an ethylene group is more preferable.
R ^f2 is preferably a fluorinated alkyl group having 1 to 6 carbon atoms.

[In the formula (a4-3),
R ^f11 represents a hydrogen atom or a methyl group.
A ^f11 represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom.
X ^f12 represents a carbonyloxy group or an oxycarbonyl group.
A ^f14 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a fluorine atom.
However, at least one of A ^f13 and A ^f14 represents an aliphatic hydrocarbon group having a fluorine atom. ]

^Examples of the alkanediyl group for A ^f11 include the same groups as the alkanediyl group for A ^f1 .

The aliphatic hydrocarbon group for A ^f13 and A ^f14 includes either a chain or a cyclic group, and a divalent aliphatic hydrocarbon group in which they are combined. The aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
The divalent aliphatic hydrocarbon group which may have a fluorine atom of A ^f13 is preferably an aliphatic saturated hydrocarbon group which may have a fluorine atom, more preferably a perfluoroalkanediyl group. It is.
Examples of the divalent chain aliphatic hydrocarbon group which may have a fluorine atom include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group; difluoromethylene group, perfluoroethylene Groups, perfluoroalkanediyl groups such as perfluoropropanediyl group, perfluorobutanediyl group and perfluoropentanediyl group.
The divalent cyclic aliphatic hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Examples of the monocyclic aliphatic hydrocarbon group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic divalent aliphatic hydrocarbon group include an adamantanediyl group, a norbornanediyl group, a perfluoroadamantanediyl group, and the like.

The aliphatic hydrocarbon group which may have a fluorine atom of A ^f14 is preferably an aliphatic saturated hydrocarbon group which may have a fluorine atom.
Examples of the chain aliphatic hydrocarbon group which may have a fluorine atom include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group, 1,1 , 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 , 4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group and pentyl group, hexyl group, perfluorohexyl group, A heptyl group, a perfluoro heptyl group, an octyl group, a perfluorooctyl group, etc. are mentioned.
Etc.
The cyclic aliphatic hydrocarbon group which may have a fluorine atom may be monocyclic or polycyclic. Examples of the group containing a monocyclic aliphatic hydrocarbon group include a cyclopropylmethyl group, a cyclopropyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, and a perfluorocyclohexyl group. Examples of the group containing a polycyclic aliphatic hydrocarbon group include an adamantyl group, an adamantylmethyl group, a norbornyl group, a norbornylmethyl group, a perfluoroadamantyl group, and a perfluoroadamantylmethyl group.

A ^f11 in formula (a4-3) is an ethylene group is preferred.
The aliphatic hydrocarbon group for A ^f13 preferably has 1 to 6 carbon atoms, and more preferably 2 to 3 carbon atoms.
The aliphatic hydrocarbon group for A ^f14 preferably has 3 to 12 carbon atoms, and more preferably 3 to 10 carbon atoms. Among them, A ^f14 is preferably a group containing an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group.

Examples of the monomer for deriving the structural unit represented by formula (a4-2) include monomers represented by formula (a4-1-1) to formula (a4-1-22), respectively.

Examples of the monomer for deriving the structural unit represented by formula (a4-3) include monomers represented by formula (a4-1′-1) to formula (a4-1′-22), respectively.

Examples of the structural unit (a4) include a structural unit represented by the formula (a4-4).
[In the formula (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 represents — (CH ₂ ) _j1 —, — (CH ₂ ) _j2 —O— (CH ₂ ) _j3 — or — (CH ₂ ) _j4 —CO—O— (CH ₂ ) _j5 —.
j1 to j5 each independently represents an integer of 1 to 6.
R ^f22 represents a C 1-10 hydrocarbon group having a fluorine atom. ]

^Examples of the hydrocarbon group having a fluorine atom of R ^f22 include the same hydrocarbon groups as R ^f2 in formula (a4-2).

In formula (a4-4), A ^f21 is preferably — (CH ₂ ) _j1 —, more preferably an ethylene group or a methylene group, and still more preferably a methylene group.
R ^f22 is preferably a ^C 1-10 alkyl group having a fluorine atom or a C 1-10 alicyclic hydrocarbon group having a fluorine atom, more preferably a C 1-10 alkyl group having a fluorine atom. Preferably, the C1-C6 alkyl group which has a fluorine atom is further more preferable.

Examples of the monomer for deriving the structural unit represented by the formula (a4-4) include the following monomers.

  When the resin (A) has a structural unit (a4), the content is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, based on all structural units of the resin (A). More preferably, it is 10 mol%.

  The resin (A) may have a structural unit other than the above-described structural unit, and examples of the structural unit include structural units well known in the art.

The resin (A) is preferably a resin composed of the structural unit (a1) and the structural unit (s). In this case, each of these contents is based on all structural units of the resin (A).
Structural unit (a1); 10-95 mol%
Structural unit (s); 5-90 mol%
Is preferred,
Structural unit (a1); 15 to 90 mol%
Structural unit (s); 10-85 mol%
Is more preferred,
Structural unit (a1); 20 to 85 mol%
Structural unit (s); 15-80 mol%
Is more preferable.

The structural unit (a1) is preferably at least one of the structural unit (a1-1) and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group), more preferably the structural unit (a1- 1).
The structural unit (s) is preferably at least one of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit represented by the formula (a2-1).
The structural unit (a3) is preferably at least one of a structural unit represented by the formula (a3-1) and a structural unit represented by the formula (a3-2).

  The resin (A) may contain a structural unit derived from a monomer having an adamantyl group (particularly the structural unit (a1-1)) in an amount of 15 mol% or more based on the content of the structural unit (a1). preferable. When the content of the structural unit having an adamantyl group is increased, the dry etching resistance of the resist pattern is improved.

Each structural unit constituting the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (for example, radical polymerization method) using a monomer that derives these structural units. can do. The content rate of each structural unit which resin (A) has can be adjusted with the usage-amount of the monomer used for superposition | polymerization.
The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more, more preferably 4,000 or more), 50,000 or less (more preferably 30,000 or less, and further preferably 15,000 or less).

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). An example of such a resin is a resin composed of only the structural unit (s).
Among these, as the resin other than the resin (A), a resin having the structural unit (a4) (however, the structural unit (a1) is not included. Hereinafter, it may be referred to as “resin (X)”) is preferable. In the resin (X), the content ratio of the structural unit (a4) is preferably 80 mol% or more, more preferably 85 mol% or more, and still more preferably 90 mol% or more with respect to all the structural units of the resin (X). .
Examples of the structural unit that the resin (X) may further include a structural unit derived from the structural unit (a2), the structural unit (a3), and other known monomers.
The weight average molecular weight of the resin (X) is preferably 8,000 or more (more preferably 10,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight average molecular weight of the resin (X) is the same as that for the resin (A).

  When the resist composition of this invention contains resin (X), the content becomes like this. Preferably it is 1-60 mass parts with respect to 100 mass parts of resin (A), More preferably, it is 3-50 mass parts More preferably, it is 5-40 mass parts, Most preferably, it is 7-30 mass parts.

  The resin content in the resist composition of the present invention is preferably 80% by mass or more and 99% by mass or less with respect to the solid content of the resist composition. In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described later from the total amount of the resist composition. The solid content of the resist composition and the resin content relative to the solid content can be measured, for example, by known analytical means such as liquid chromatography or gas chromatography.

<Acid generator (B)>
The acid generator (B) may be either nonionic or ionic. Examples of the nonionic acid generator include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4). -Sulfonate), sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane) and the like. Examples of the ionic acid generator include onium salts containing onium cations (for example, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts) and the like. Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  Examples of the acid generator (B) include JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, JP-A-62-153853, JP-A-63-146029, US Pat. No. 3,779,778, US Pat. No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712 The compound which generate | occur | produces an acid by the radiation as described in etc. can be used.

  The acid generator (B) is preferably a fluorine-containing acid generator, more preferably a salt represented by the formula (B1) (hereinafter sometimes referred to as “salt (B1)”).

[In the formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and one or more methylene groups constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y represents an alkyl group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent. One or more methylene groups constituting the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Zb ⁺ represents an organic cation. ]

Examples of the perfluoroalkyl group for Q ^b1 and Q ^b2 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluoro sec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, A perfluorohexyl group etc. are mentioned.
Q ^b1 and Q ^b2 are each independently preferably a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group for L ^b1 include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and the like. Two or more of these groups may be combined.
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;
Butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4- Branched alkanediyl groups such as diyl groups;
Monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group, etc. Groups and the like.

Examples of the group in which one or more methylene groups constituting the divalent saturated hydrocarbon group of L ^b1 are replaced by an oxygen atom or a carbonyl group include any of the formulas (b1′-1) to (b1′-7) The group represented by is mentioned. L ^b1 is preferably a group represented by any one of formulas (b1′-1) to (b1′-4), more preferably represented by formula (b1′-1) or formula (b1′-2). Group to be used. In addition, Formula (b1'-1)-Formula (b1'-7) has described the right and left according to Formula (B1), and it is C on the left side among the two bonds represented by *, respectively. It binds to (Q ^b1 ) (Q ^b2 ) — and on the right side to —Y. The same applies to specific examples of the following formulas (b1′-1) to (b1′-7).

In formula (b1′-1) to formula (b1′-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 divalent saturated hydrocarbon group having 1 to 13 carbon atoms. However, the upper limit of the total carbon number of L ^{b3 ′} and L ^{b4 ′} is 13.
L ^{b5 ′} represents a single bond or a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^{b6 ′} represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^{b5 ′} and L ^{b6 ′} is 15.
L ^{b7 ′} represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^{b8 ′} represents a divalent saturated hydrocarbon group having 1 to 16 carbon atoms. However, the upper limit of the total carbon number of L ^{b7 ′} and L ^{b8 ′} is 16.
L ^{b9 ′} represents a single bond or a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^{b10 ′} represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^{b9 ′} and L ^{b10 ′} is 14.
L ^{b11 ′} and L ^{b12 ′} each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^{b13 ′} represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms. However, the upper limit of the total carbon number of L ^{b11 ′} , L ^{b12 ′} and L ^{b13 ′} is 12.
L ^{b14 ′} and L ^{b15 ′} each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^{b16 ′} represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^{b14 ′} , L ^{b15 ′} and L ^{b16 ′} is 14.

Examples of the group represented by the formula (b1′-1) include the following.

Examples of the group represented by the formula (b1′-2) include the following.

Examples of the group represented by the formula (b1′-3) include the following.

Examples of the group represented by the formula (b1′-4) include the following.

Examples of the group represented by the formula (b1′-5) include the following.

Examples of the group represented by the formula (b1′-6) include the following.

Examples of the group represented by the formula (b1′-7) include the following.

Examples of the alkyl group for Y include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, heptyl group, 2 -Alkyl groups, such as an ethylhexyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, are mentioned, Preferably a C1-C6 alkyl group is mentioned.
Examples of the alicyclic hydrocarbon group include groups represented by formulas (Y1) to (Y11).
Examples of the group in which one or more methylene groups constituting the alicyclic hydrocarbon group of Y are replaced with an oxygen atom, a sulfonyl group, or a carbonyl group include groups represented by formulas (Y12) to (Y26). It is done.

  Especially, it is preferably a group represented by any one of formulas (Y1) to (Y19), more preferably represented by formula (Y11), formula (Y14), formula (Y15) or formula (Y19). And more preferably a group represented by formula (Y11) or formula (Y14).

Examples of the substituent of the alkyl group in Y include, for example, a halogen atom, a hydroxy group, an oxo group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, and 2 to 2 carbon atoms. 4 acyl group, glycidyloxy group or — (CH ₂ ) _j2 —O—CO—R ^b1 group (wherein R ^b1 is an alkyl group having 1 to 16 carbon atoms, alicyclic carbonization having 3 to 16 carbon atoms) Represents a hydrogen group or an aromatic hydrocarbon group having 6 to 18 carbon atoms, j2 represents an integer of 0 to 4).
Examples of the substituent of the alicyclic hydrocarbon group in Y include, for example, a halogen atom, a hydroxy group, an oxo group, an alkyl group having 1 to 12 carbon atoms, a hydroxy group-containing alkyl group having 1 to 12 carbon atoms, and 3 to 3 carbon atoms. 16 alicyclic hydrocarbon groups, alkoxy groups having 1 to 12 carbon atoms, aromatic hydrocarbon groups having 6 to 18 carbon atoms, aralkyl groups having 7 to 21 carbon atoms, acyl groups having 2 to 4 carbon atoms, glycidyloxy Group or — (CH ₂ ) _j2 —O—CO—R ^b1 group (wherein R ^b1 is an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, or 6 to 6 carbon atoms). 18 represents an aromatic hydrocarbon group, and j2 represents an integer of 0 to 4.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the hydroxy group-containing alkyl group include a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, anthryl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group; tolyl group, xylyl group, cumenyl group, mesityl group. , Aryl groups such as biphenyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl, and the like.
Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, naphthylmethyl group, and naphthylethyl group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of Y include the following.

In addition, when Y is an alkyl group and L ^b1 is a linear alkanediyl group having 1 to 17 carbon atoms or a branched alkanediyl group, the divalent saturated hydrocarbon group at the bonding position with Y The methylene group is preferably replaced with an oxygen atom or a carbonyl group. In this case, the methylene group constituting the alkyl group of Y is not replaced with an oxygen atom or a carbonyl group. The same applies when the hydrogen atom contained in the alkyl group of Y and / or the linear alkanediyl group or branched alkanediyl group of L ^b1 is substituted with a substituent.

Y is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and more preferably an adamantyl group which may have a substituent. The constituting methylene group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Y is more preferably an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group.

The sulfonate anion in the salt (B1) is preferably an anion represented by the formula (b1-1-1) to the formula (b1-1-9). In the following formulas, the definitions of the symbols have the same meaning as described above, and R ^b2 and R ^b3 each independently represent an alkyl group having 1 to 4 carbon atoms (preferably a methyl group).
Specific examples of the sulfonate anion in the salt (B1) include anions described in JP 2010-204646 A.

Examples of the organic cation (Zb ⁺ ) contained in the salt (B1) include organic onium cations such as organic sulfonium cation, organic iodonium cation, organic ammonium cation, benzothiazolium cation, and organic phosphonium cation. , An organic sulfonium cation or an organic iodonium cation, more preferably an arylsulfonium cation, and still more preferably the same as the cation represented by any one of the formulas (b2-1) to (b2-4) described above. belongs to.

  Examples of the salt (B1) include salts represented by formula (B1-1) to formula (B1-24). Among them, those containing a triphenylsulfonium cation or a tolylsulfonium cation are preferable, and are represented by the formula (B1-1), the formula (B1-2), the formula (B1-3), the formula (B1-6), and the formula (B1-7). , Formula (B1-11), Formula (B1-12), Formula (B1-13), Formula (B1-14), Formula (B1-21), Formula (B1-22), Formula (B1-23) and A salt represented by any one of the formulas (B1-24) is more preferable.

The acid generator (B) may be used alone or in combination of two or more.
The content of the acid generator (B) in the resist composition of the present invention is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 40 parts by mass or less with respect to the total amount of the resin (A). (More preferably 35 parts by mass or less).
As described above, the acid generator (B) may contain an acid generator different from the acid generator (B1). In this case, the acid generator (B1) in the total amount of the acid generator (B). ) Is preferably 70% by mass or more, and more preferably 90% by mass or more. However, it is more preferable that the acid generator (B) in the resist composition of the present invention is substantially only the acid generator (B1).

<Salt (I)>
The salt (I) may be used alone or in combination of two or more.
The content of the salt (I) in the resist composition of the present invention is preferably 0.1 parts by mass or more (more preferably 1 part by mass or more), preferably 100 parts by mass of the resin (A). 20 parts by mass or less (more preferably 10 parts by mass or less).

<Solvent (E)>
The content of the solvent (E) is, for example, 90% by mass or more in the resist composition, preferably 92% by mass or more, more preferably 94% by mass or more, for example 99.9% by mass or less, preferably 99% by mass or less. It is. The content rate of a solvent (E) can be measured by well-known analysis means, such as a liquid chromatography or a gas chromatography, for example.

  Examples of the solvent (E) 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 pyruvic acid Examples thereof include esters such as ethyl; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; A solvent may contain individually by 1 type and may contain 2 or more types.

<Basic compound (C)>
The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. The basic compound (C) is preferably a compound represented by any one of the formulas (C1) to (C8) and (C1-1), more preferably represented by the formula (C1-1). The compound which is made is mentioned.

[In formula (C1), R ^c1 , R ^c2 and R ^c3 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or 6 to 6 carbon atoms. 10 represents an aromatic hydrocarbon group, and the hydrogen atom contained in the alkyl group and the alicyclic hydrocarbon group may be substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms, The hydrogen atom contained in the aromatic hydrocarbon group is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. It may be substituted with a group hydrocarbon group. ]

[In Formula (C1-1), R ^c2 and R ^c3 represent the same meaning as described above.
R ^c4 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, the plurality of R ^c4 are the same or different from each other. ]

[In Formula (C2), Formula (C3) and Formula (C4), R ^c5 , R ^c6 , R ^c7 and R ^c8 each independently represent the same meaning as R ^c1 .
R ^c9 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 6 carbon atoms, or an acyl group having 2 to 7 carbon atoms.
n3 represents an integer of 0 to 8, and when n3 is 2 or more, the plurality of R ^c9 are the same or different from each other. ]

[In Formula (C5) and Formula (C6), R ^c10 , R ^c11 , R ^c12 , R ^c13 and R ^c16 each independently represent the same meaning as R ^c1 .
R ^c14 , R ^c15 and R ^c17 each independently represent the same meaning as R ^c4 .
o3 and p3 each independently represent an integer of 0 to 3, and when o3 is 2 or more, the plurality of R ^c14 are the same or different from each other, and when p3 is 2 or more, the plurality of R ^c15 are the same as each other Or different.
L ^c1 represents an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

Wherein (C7) and formula ^{(C8), R c18, R} c19 and R ^c20 in each occurrence independently represent the same meaning as R ^c4.
q3, r3 and s3 each independently represents an integer of 0 to 3. When q3 is 2 or more, the plurality of R ^c18 are the same or different from each other, and when r3 is 2 or more, the plurality of R ^c19 are When the same or different from each other and s3 is 2 or more, the plurality of R ^c20 are the same or different from each other.
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

In formula (C1) to formula (C8) and formula (C1-1), the alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, alkoxy group, alkanediyl group are the same as those described above. Is mentioned.
Examples of the acyl group include acetyl group, 2-methylacetyl group, 2,2-dimethylacetyl group, propionyl group, butyryl group, isobutyryl group, pentanoyl group, and 2,2-dimethylpropionyl group.

  Examples of the compound represented by the formula (C1) include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N- Dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tri Pentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyl Hexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonyl Amine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2- Examples include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and preferably diisopropyl. Piruanirin. Particularly preferred include 2,6-diisopropylaniline.

Examples of the compound represented by the formula (C2) include piperazine.
Examples of the compound represented by the formula (C3) include morpholine.
Examples of the compound represented by the formula (C4) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound represented by the formula (C5) include 2,2′-methylenebisaniline.
Examples of the compound represented by the formula (C6) include imidazole and 4-methylimidazole.
Examples of the compound represented by the formula (C7) include pyridine and 4-methylpyridine.
Examples of the compound represented by the formula (C8) 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′-dipyridyl disulfide, 2,2′-dipyridylamine, 2,2′-dipiconylamine, bipyridine and the like.

  As ammonium salts, tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethyl Ammonium hydroxide, tetra-n-butylammonium salicylate, choline and the like can be mentioned.

  The content of the basic compound (C) in the solid content of the resist composition is preferably about 0.01 to 5% by mass, more preferably about 0.01 to 3% by mass, and particularly preferably 0.8. It is about 01 to 1% by mass.

<Other components (hereinafter sometimes referred to as “other components (F)”)>
The resist composition may contain other components (F) as necessary. The other component (F) is not particularly limited, and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, and the like can be used.

<Preparation of resist composition>
The resist composition is obtained by mixing the resin, the acid generator (B) and the salt (I), and the solvent (E), basic compound (C) and other components (F) used as necessary. Can be prepared. The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select the suitable temperature range from the range of 10-40 degreeC according to the solubility with respect to the solvent (E), such as a kind, etc. of resin. The mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<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, (5) The process of developing the composition layer after a heating is included.

  Application of the resist composition onto the substrate can be performed by a commonly used apparatus such as a spin coater. By adjusting the conditions of the coating apparatus, the film thickness of the composition after coating can be adjusted. Examples of the substrate include a silicon wafer. Before applying the resist composition, the substrate may be washed or an antireflection film may be formed using a commercially available organic antireflection film composition.

By drying the composition after coating, the solvent is removed and a composition layer is formed. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or using a decompression device. The heating temperature is preferably 50 to 200 ° C., for example, and the heating time is preferably 10 to 180 seconds, for example. The pressure during drying under reduced pressure is preferably about 1 to 1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. Exposure light sources include those that emit laser light in the ultraviolet region such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser) Etc.) using various types of laser light such as those that convert the wavelength of laser light from the laser to emit harmonic laser light in the far-ultraviolet region or vacuum ultraviolet region, those that irradiate electron beams, extreme ultraviolet light (EUV), etc. it can. In this specification, irradiating these radiations may be collectively referred to as “exposure”. The exposure is usually performed through a mask corresponding to a desired resist pattern. When the exposure light source is an electron beam, a desired pattern may be directly drawn without using a photomask.

  The composition layer after exposure is subjected to heat treatment (so-called post-exposure baking) in order to promote the deprotection reaction of the acid labile group of the resin (A). As heating temperature, it is about 50-200 degreeC normally, Preferably it is about 70-150 degreeC.

  The heated composition layer is usually developed using a developer 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 is a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, particularly a liquid. It is suitable as a resist composition for immersion exposure and useful for fine processing of semiconductors.

Hereinafter, the present invention will be described in detail by way of examples.
In Examples and Comparative Examples, “%” and “part” representing the content and the amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value determined under the following conditions by gel permeation chromatography using polystyrene as a standard product.
Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore H _XL -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)
The structure of the compound was confirmed by measuring the molecular peak using mass spectrometry (LC is model 1100 manufactured by Agilent, and MASS is LC / MSD manufactured by Agilent). In the following examples, the value of this molecular peak is indicated by “MS”.

Example 1: Synthesis of salt (I) represented by formula (I-1)
A mixture obtained by adding 1.58 parts of silver (I) oxide to a solution obtained by mixing 4.63 parts of the compound represented by the formula (I-1-b) and 49.1 parts of methanol, Stir at room temperature for 3 hours.
To the obtained reaction mixture solution, 5.34 parts of the salt represented by the formula (I-1-a) was added, and the mixture was stirred at room temperature for 18 hours. The reaction mixture solution was filtered, and the resulting filtrate was concentrated under reduced pressure. Chloroform was added to the resulting residue, washed with ion exchange water, and concentrated under reduced pressure. A mixed solution of acetonitrile and 2-methoxy-2-methylpropane was added to the obtained residue, and the mixture was stirred and filtered. The obtained solid was dried to obtain 6.5 parts of the salt represented by the formula (I-1).

MS (ESI (+) Spectrum): M ⁺ = 263.1 (C ₁₈ H ₁₅ S ⁺ = 263.1)
MS (ESI (−) Spectrum): M ⁻ = 353.1 (C ₁₆ H ₂₁ F ₄ O ₄ ⁻ = 353.1)

Example 2: Synthesis of salt (I) represented by formula (I-18)
A mixture obtained by adding 1.83 parts of silver (I) oxide to a solution obtained by mixing 4.0 parts of the compound represented by the formula (I-18-b) and 40.0 parts of methanol, Stir at room temperature for 3 hours.
To the obtained reaction mixture solution, 6.17 parts of the salt represented by the formula (I-18-a) was added and stirred at room temperature for 18 hours. The reaction mixture solution was filtered, and the resulting filtrate was concentrated under reduced pressure. Chloroform was added to the resulting residue, washed with ion exchange water, and concentrated under reduced pressure. A mixed solution of acetonitrile and 2-methoxy-2-methylpropane was added to the obtained residue, and the mixture was stirred and filtered. The obtained solid was dried to obtain 8.5 parts of the salt represented by the formula (I-18).

MS (ESI (+) Spectrum): M ⁺ = 263.1 (C ₁₈ H ₁₅ S ⁺ = 263.1)
MS (ESI (−) Spectrum): M ⁻ = 353.1 (C ₁₄ H ₂₁ O ₄ ⁻ = 253.1)

Example 3: Synthesis of salt (I) represented by formula (I-30)
A mixture obtained by adding 1.29 parts of silver (I) oxide to a solution obtained by mixing 4.00 parts of the compound represented by the formula (I-30-b) and 40.0 parts of methanol, Stir at room temperature for 3 hours.
To the obtained reaction mixture solution, 4.82 parts of the salt represented by the formula (I-30-a) was added and stirred at room temperature for 18 hours. The reaction mixture solution was filtered, and the resulting filtrate was concentrated under reduced pressure. Chloroform was added to the resulting residue, washed with ion exchange water, and concentrated under reduced pressure. A mixed solution of acetonitrile and 2-methoxy-2-methylpropane was added to the obtained residue, and the mixture was stirred and filtered. The obtained solid was dried to obtain 6.1 parts of the salt represented by the formula (I-30).

^{MS (ESI (+) Spectrum)} : M + = 305.1 (C 21 H 21 S + = 305.1)
MS (ESI (−) Spectrum): M ⁻ = 353.1 (C ₁₆ H ₂₁ F ₄ O ₄ ⁻ = 353.1)

Example 4: Synthesis of salt (I) represented by formula (I-31)
A mixture obtained by adding 1.29 parts of silver (I) to a solution obtained by mixing 4.00 parts of the compound represented by the formula (I-31-b) and 40.0 parts of methanol, Stir at room temperature for 3 hours.
To the obtained reaction mixture solution, 5.34 parts of the salt represented by the formula (I-31-a) was added, and the mixture was stirred at room temperature for 18 hours. The reaction mixture solution was filtered, and the resulting filtrate was concentrated under reduced pressure. Chloroform was added to the resulting residue, washed with ion exchange water, and concentrated under reduced pressure. A mixed solution of acetonitrile and 2-methoxy-2-methylpropane was added to the obtained residue, and the mixture was stirred and filtered. The obtained solid was dried to obtain 8.1 parts of the salt represented by the formula (I-31).

^{MS (ESI (+) Spectrum)} : M + = 431.1 (C 30 H 39 S + = 431.3)
MS (ESI (−) Spectrum): M ⁻ = 353.1 (C ₁₆ H ₂₁ F ₄ O ₄ ⁻ = 353.1)

Resin synthesis Monomers used for resin synthesis are shown below.
Hereinafter, these monomers are referred to as “monomer (a1-1-1)” or the like according to the formula number.

Synthesis Example 1 [Synthesis of Resin A1]
As the monomer, using monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-2-3): monomer (a3-1-1)] 45: 14: 2.5: 22: 16.5, and 1.5 mass times propylene glycol monomethyl ether acetate of the total monomer amount was added to make a solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 0.95 mol% and 2.85 mol%, respectively, based on the total monomer amount, and these were added at 73 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin obtained was dissolved again in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and the weight-average molecular weight was 7. 9 × 10 ³ resin A1 was obtained with a yield of 73%. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin A2]
As the monomer, using monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3), monomer (a3-2-3) and monomer (a3-4-1), The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-2-3): monomer (a3-4-1)] It mixed so that it might be set to 45: 14: 2.5: 22.5: 16, and 1.5 mass times dioxane of the total monomer amount was added, and it was set as the solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 73 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was dissolved again in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 8.8. A × 10 ³ resin A2 (copolymer) was obtained with a yield of 71%. This resin A2 has the following structural units.

Synthesis Example 3 [Synthesis of Resin A3]
As the monomer, monomer (a1-1-1), monomer (a2-1-1), and monomer (a3-1-1) were used, and the molar ratio [monomer (a1-1-1): monomer (a2- 1-1): monomer (a3-1-1)] was mixed to be 35:25:40, and 1.5 mass times propylene glycol monomethyl ether acetate of the total monomer amount was added to obtain a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol solvent to precipitate the resin, and the resin was filtered. The resin obtained was again dissolved in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 8. 7 × 10 ³ resin A3 was obtained with a yield of 90%. This resin A3 has the following structural units.

Synthesis Example 4 [Synthesis of Resin H1]
As the monomer, monomer (a4-x) and monomer (a1-2-9) are used, and the molar ratio [monomer (a4-x): monomer (a1-2-9)] is 50:50. After mixing, methyl isobutyl ketone 1.2 times the total monomer amount was added to make a solution. To the solution, azobis (2,4-dimethylvaleronitrile) as an initiator was added in an amount of 3 mol% based on the total monomer amount, and these were heated at 70 ° C. for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained was again dissolved in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin. Resin H1 having an average molecular weight of 9.0 × 10 ³ was obtained with a yield of 85%. This resin H1 has the following structural units.

Synthesis Example 5 [Synthesis of Resin H2]
Monomer (a4-z) was used as a monomer, and 4.0 mass times propylene glycol monomethyl ether acetate as a total monomer amount was added to prepare a solution. To the solution, 8 mol% of V-601 (manufactured by Wako Pure Chemical Industries) as an initiator was added with respect to the total amount of monomers, and these were heated at 80 ° C. for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained was again dissolved in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin. Resin H1 having an average molecular weight of 7.6 × 10 ³ was obtained with a yield of 70%. This resin H2 has the following structural units.

Examples 5 to 9 and Comparative Example 1
<Preparation of resist composition>
As shown in Table 1, each component was mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Acid generator>
II-2: Central Glass
B1-3: synthesized according to the example of JP 2010-152341 A
Z1: (Wako Pure Chemical Industries, Ltd.)

<Resin>
A1: Resin A1
A2: Resin A2
A3: Resin A3
H1: Resin H1
H2: Resin H2

<Salt (I)>
I-1: salt represented by formula (I-1)
I-18: salt represented by formula (I-18)
I-30: salt represented by formula (I-30)
I-31: salt represented by formula (I-31)

<Basic compound: Quencher>
C1: 2,6-diisopropylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.)
<Solvent>
Propylene glycol monomethyl ether acetate 250 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 3.5 parts

<Manufacture of negative resist pattern>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer, and baked under the conditions of 205 ° C. and 60 seconds, whereby an organic layer having a thickness of 78 nm was obtained. An antireflection film was formed. Next, the resist composition was spin-coated on the organic antireflection film so that the film thickness of the composition layer after drying (pre-baking) was 110 nm. After coating, the composition layer was formed on the silicon wafer by pre-baking on a direct hot plate for 60 seconds at the temperature described in the “PB” column of Table 1. An ArF excimer laser stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, Annular illumination, x, y-polarized light) is applied to the composition layer formed on the silicon wafer with a hole pattern (pitch Using a mask for forming (70 nm / hole diameter 50 nm), the exposure amount was changed stepwise to perform exposure. Note that ultrapure water was used as the immersion medium. After the exposure, post-exposure baking was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 1. Next, the composition layer on the silicon wafer is developed by using a butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution by a dynamic dispensing method at 23 ° C. for 20 seconds, thereby forming a negative resist pattern. Manufactured.

  In the obtained resist pattern, an exposure amount at which the diameter of the hole pattern was 55 nm was defined as effective sensitivity.

<Evaluation of CD uniformity (CDU)>
In terms of effective sensitivity, the hole diameter formed with a mask having a pitch of 70 nm and a hole diameter of 50 nm was measured 24 times per hole, and the average value was taken as the average hole diameter of one hole.
The standard deviation was determined using a population of 105 measured average hole diameters of patterns formed with a mask having a pitch of 70 nm and a hole diameter of 50 nm in the same wafer. The results are shown in Table 2.

  According to the resist composition of the present invention, a resist pattern having excellent resolution and CD uniformity (CDU) can be produced.

Claims (3)

A salt represented by the formula (I).
[L ¹ represents a single bond .
Ring W ¹ represents an adamantane ring.
a1 and a2 represents 0.
R ¹ and R ² each independently represent a saturated hydrocarbon group having 1 to 10 carbon atoms, these are attached
Together with it forms a ring. * Represents a bond.
Z ⁺ represents an organic cation. ] A resist composition for developing an organic solvent comprising a resin having an acid labile group, an acid generator, and a salt represented by the formula (I) according to claim 1. (1) The process of apply | coating the resist composition of Claim 2 on a board | 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) heating the composition layer after exposure, and (5) the method for production of a resist pattern including the heated composition layer as engineering developed with organic solvents.