JP6757171B2 - Method for Producing Salt, Resist Composition and Resist Pattern - Google Patents

Description

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

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

Patent Document 2 describes a resist composition containing a salt represented by the following formula as an acid generator.

Japanese Unexamined Patent Publication No. 2003-342254 Japanese Unexamined Patent Publication No. 2012-97074

In the resist composition containing the above-mentioned salt, the focus margin (DOF) of the resist pattern may not always be sufficiently satisfied.

The present invention includes the following inventions.
[1] A salt having at least one anion having a group represented by the formula (Ia) and a cation represented by the formula (IC).
[In formula (Ia),
X ^a and X ^b represent an oxygen atom or a sulfur atom independently of each other.
X ¹ represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms having at least one fluorine atom.
* Represents a bond. ]
[In the formula (IC),
R ¹ and R ² independently represent a hydrogen atom, a hydroxy group, or a hydrocarbon group having 1 to 12 carbon atoms, and −CH ₂ − contained in the hydrocarbon group is −O− or −CO−. It may be replaced.
m and n represent 1 or 2 independently of each other. when m is 2, two R ¹ may be the same or different, when n is 2, the two R ² may be the same or different.
Ar ¹ and Ar ² are independently of each other, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic aromatic group having 6 to 36 carbon atoms which may have a substituent. Represents a hydrocarbon group. ]
[2] The salt according to [1], wherein the anion having a group represented by the formula (Ia) is an anion having a group represented by the formula (Ia1).
[In formula (Ia1),
X ^a , X ^b , X ¹ and * have the same meanings as above.
Ring W represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. Often, the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and the methylene group contained in the hydrocarbon group may be an oxygen atom or an oxygen group. It may be substituted with a carbonyl group. ]
[3] The salt according to [2], wherein the anion having a group represented by the formula (Ia1) is an anion having a group represented by the formula (Ia2).
[In formula (Ia2),
The rings W and * have the same meanings as above.
R ^f1 and R ^f2 independently represent a fluorine atom or an alkyl fluoride group having 1 to 6 carbon atoms.
nx represents an integer from 1 to 10. When nx is 2 or more, a plurality of R ^f1 and R ^f2 existing may be the same or different. ]
[4] Ring W is a ring represented by the formula (Iaa-1), a ring represented by the formula (Iaa-2), or a ring represented by the formula (Iaa-3) [2] or [3]. ] Described salt.
[In the formula (Iaa-1), the formula (Iaa-2) and the formula (Iaa-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, and the hydrogen atom contained in the ring is substituted with a hydroxy group and a hydrocarbon group having 1 to 12 carbon atoms. The methylene group contained in the hydrocarbon group may be substituted with an oxygen atom or a carbonyl group. ]
[5] The salt according to any one of [1] to [4], wherein the anion having a group represented by at least one formula (Ia) is an anion represented by the formula (IA).
[In formula (IA),
X ^a , X ^b , X ¹ and W have the same meanings as described above.
Q ¹ and ^{Q 2} independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the saturated hydrocarbon group may be replaced. The hydrogen atom contained in the hydrogen group may be substituted with a fluorine atom or a hydroxy group. ]
[6] The salt according to any one of [1] to [4], which has two anions having a group represented by the formula (Ia).
[7] The salt according to [6], wherein the two anions are both anions represented by the formula (IA).
[In formula (IA),
X ^a , X ^b , X ¹ and W have the same meanings as above.
Q ¹ and ^{Q 2} independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the saturated hydrocarbon may be replaced. The hydrogen atom contained in the hydrogen group may be substituted with a fluorine atom or a hydroxy group. ]
[8] L ^b1 is * -CO-O- (CH ₂ ) _t- or * -CH _2- O-CO- (t represents an integer of 0 to 6. * Is -C (Q ¹ ) ( Q ²⁾ -. representing a bond to) a [5] salt according to any one of - [7].
[9] An acid generator containing the salt according to any one of [1] to [8] as an active ingredient.
[10] A resist composition containing the acid generator according to [9] and a resin containing a structural unit having an acid unstable group.
[11] The resist composition according to [10], which further comprises an acid generator represented by the formula (B1).
[In equation (B1),
Q ^{1, Q 2} and ^{L b1} are the same as defined above.
Y represents a methyl group which may have a substituent or a monovalent alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and the monovalent alicyclic hydrocarbon. -CH _2- contained in the hydrogen group may be replaced with -O-, -SO _2- or -CO-.
Z ⁺ represents an organic cation. However, Z ⁺ does not include the cation represented by the formula (IC). ]
[12] The resist composition according to [10] or [11], which further contains a resin containing a structural unit having a fluorine atom.
[13] The resist composition according to any one of [10] to [12], further containing a salt that generates an acid having a weaker acidity than the acid generated from the acid generator.
[14] (1) A step of applying the resist composition according to any one of [10] to [13] onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
A method for producing a resist pattern, which comprises a step of (4) heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

It is possible to provide a salt capable of producing a resist pattern with a good focus margin (DOF).

In the present specification, unless otherwise specified, in the description of the structural formula of a compound, "aliphatic hydrocarbon group" means a linear or branched hydrocarbon group, and "aliphatic hydrocarbon group" means a fat. It means a group obtained by removing a number of hydrogen atoms corresponding to a valence from the ring of a cyclic hydrocarbon. The "aromatic hydrocarbon group" also includes a group in which a hydrocarbon group is bonded to an aromatic ring. If a steric isomer is present, it includes all steric isomers.
As used herein, the term "(meth) acrylic monomer" means at least one type of monomer having a structure of "CH ₂ = CH-CO-" or "CH ₂ = C (CH ₃ ) -CO-". 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. In addition, any of the groups described in the present specification that can have both a linear structure and a branched structure may be used.
In the present specification, the "solid content of the resist composition" means the total amount of the components excluding the solvent (E) described later from the total amount of the resist composition.

<Salt (I)>
The salt of the present invention (hereinafter sometimes referred to as "salt (I)") is a salt having an anion having a group represented by at least one formula (Ia).
[In formula (Ia),
X ^a and X ^b represent an oxygen atom or a sulfur atom independently of each other.
X ¹ represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms having at least one fluorine atom.
* Represents a bond. ]

It is preferable that X ^a and X ^b are the same atom, and it is more preferable that both are oxygen atoms.
Examples of the saturated hydrocarbon group include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and two or more of these groups are used. May be a combination of.
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, nonan-1,9-diyl group, decan-1,10-diyl group, undecane-1,11-diyl group , Dodecane-1,12-diyl group and other linear alcandiyl groups;
A linear alkanediyl group with an alkyl group (particularly, an alkyl group having 1 to 4 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, etc.) Butan-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl, etc. A branched alkanediyl group such as a group, 2-methylbutane-1,4-diyl group;
Cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,2-diyl group, 1-methylcyclohexane-1,2-diyl group, cyclohexane-1,4-diyl group, cyclo A monocyclic divalent alicyclic saturated hydrocarbon group which is a cycloalkanediyl group such as an octane-1,2-diyl group and a cyclooctane-1,5-diyl group;
Norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantan-1,5-diyl group, adamantan-2,6-diyl group, etc. Examples thereof include a divalent alicyclic saturated hydrocarbon group.
Further, the divalent alicyclic hydrocarbon group may be a group obtained by removing any one hydrogen atom from the monovalent alicyclic hydrocarbon group shown in the present specification.
At least one of the hydrogen atoms contained in the saturated hydrocarbon group is replaced by a fluorine atom.

The anion in the salt (I) preferably has an anion having a group represented by at least one formula (Ia1).
[In formula (Ia1),
X ^a , X ^b , X ¹ and * have the same meanings as above.
Ring W represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. Often, the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and the methylene group contained in the hydrocarbon group may be an oxygen atom or an oxygen group. It may be substituted with a carbonyl group. ]

Examples of the alicyclic hydrocarbon group having 3 to 36 carbon atoms in the ring W include rings represented by the formulas (Iaa-1) to (Iaa-11), and the alicyclic hydrocarbon group having 3 to 18 carbon atoms can be mentioned. A hydrogen group is preferable, and a ring represented by the formula (Iaa-1), a ring represented by the formula (Iaa-2), or a ring represented by the formula (Iaa-3) is more preferable.
Any carbon atom in the ring of the formula (Iaa1-1) ~ formula (Iaa1-11) is may be attached and ^{X a} and ^{X b,} which of the carbon atoms, in the formula (aa1) * It may be a bond represented by.

Among them, the ring W is preferably a ring represented by the formula (Iaa-1), a ring represented by the formula (Iaa-2), or a ring represented by the formula (Iaa-3). It is more preferable to have a binding hand at the position.
The hydrocarbon group having 1 to 12 carbon atoms which may be substituted with the alicyclic hydrocarbon group of the formulas (Iaa-1) to (Iaa-11) is preferably a saturated hydrocarbon, for example, methyl. Linear or branched saturated hydrocarbons such as groups, ethyl groups, propyl groups, butyl groups, pentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, decyl groups, undecyl groups, dodecyl groups, phenyl groups, naphthyl groups. Examples thereof include aromatic hydrocarbon groups such as, and cyclic saturated hydrocarbons such as the groups shown below.

Examples of the group in which the methylene group contained in the hydrocarbon group in the formulas (Iaa-1) to (Iaa-11) is substituted with an oxygen atom or a carbonyl group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentyl. Alkoxy groups having 1 to 12 carbon atoms such as oxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group; carboxyl group, methoxycarbonyl group, ethoxy Examples thereof include an alkoxycarbonyl group having 2 to 12 carbon atoms such as a carbonyl group.
In particular, the ring W preferably has a hydroxy group, an alkoxy group, or an alkoxycarbonyl group as a substituent.

The anion having a group represented by the formula (Ia1) is preferably an anion having a group represented by the formula (Ia2).
[In formula (Ia2),
The rings W and * have the same meanings as above.
R ^f1 and R ^f2 independently represent a fluorine atom or an alkyl fluoride group having 1 to 6 carbon atoms.
nx represents an integer of 1 to 10. When nx is 2 or more, a plurality of R ^f1 and R ^f2 existing may be the same or different. ]

Examples of the alkyl fluoride group of R ^f1 and R ^f2 include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, and 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, 1- (trifluoromethyl) -2,2,2-trifluoroethyl 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- (perfluoropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, 1,1,2,2,3 , 3,4,5,4,5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluoro) Butyl) ethyl group, 1,1,2,2,3,3,4,5,5-decafluorohexyl group, 1,1,2,2,3,4,4,5,5 Examples thereof include 6,6-dodecafluorohexyl group, perfluoropentylmethyl group and perfluorohexyl group, and preferably trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group, nonafluorobutyl group and the like.
It is preferable that both R ^f1 and R ^f2 are fluorine atoms.

nx 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 even more preferably an integer of 1 to 3. ..
Among them, in the formula (Ia2), the partial structure excluding the ring W (the group represented by the formula (Ia)) includes —O—C—O— and is a partial structure represented by the following. Is preferable.

The anion in the salt (I) preferably has at least one anion having a group represented by the formula (Ia), and more preferably has at least one anion having a group represented by the formula (Ia1). , It is more preferable to have at least one anion having a group represented by the formula (IA2), even more preferably to have at least one anion represented by the formula (IA), and it is represented by the formula (IA). It is particularly preferable to have two anions.
[In formula (IA),
X ^a , X ^b , X ¹ and W have the same meanings as above.
Q ¹ and ^{Q 2} independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the saturated hydrocarbon may be replaced. The hydrogen atom contained in the hydrogen group may be substituted with a fluorine atom or a hydroxy group. ]

The perfluoroalkyl group of Q ¹ and Q ^2, a trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, a perfluoro sec- butyl group, perfluoro-tert- butyl group, perfluoropentyl group, and a perfluoro Hexyl groups and the like can be mentioned.
Q ¹ and Q ² each independently is preferably a fluorine atom or a trifluoromethyl group, Q ¹ and Q ² is more preferably both fluorine atoms.

Examples of the divalent saturated hydrocarbon group of L ^b1 include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. A combination of two or more of the groups may be used.
Specifically, methylene group, ethylene group, propane-1,3-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, Nonan-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 and heptadecane-1,17-diyl group. Alcandiyl group;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- A branched alkanediyl group such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 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, etc. Valuable alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbons such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and adamantane-2,6-diyl group. The group etc. can be mentioned.

Examples of the group in which -CH _2- contained in the divalent saturated hydrocarbon group of L ^b1 is replaced with -O- or -CO- are any of the formulas (b1-1) to (b1-3). The group represented by is mentioned. In the formulas (b1-1) to (b1-3) and the following specific examples, * represents a bond with the ring W.

[In equation (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. The methylene group contained in the hydrogen group may be replaced with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b2 and L ^b3 is 22 or less.
In equation (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. The methylene group contained in the hydrogen group may be replaced with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b4 and L ^b5 is 22 or less.
In equation (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. The methylene group contained in the hydrogen group may be replaced with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b6 and L ^b7 is 23 or less. ]

In the formulas (b1-1) to (b1-3), when the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group, the number of carbon atoms before the replacement is the saturated hydrocarbon group. The number of carbon atoms in.
Examples of the divalent saturated hydrocarbon group include those similar to the divalent saturated hydrocarbon group of L ^b1 .

L ^b2 is preferably a single bond.
L ^b3 is preferably an alkanediyl group having 1 to 4 carbon atoms.
L ^b4 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b6 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. The methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.

Of these, the groups represented by the formula (b1-1) or the formula (b1-3) are preferable.

Examples of the formula (b1-1) include groups represented by the formulas (b1-4) to (b1-8), respectively.
[In equation (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In equation (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total number of carbon atoms of L ^b9 and L ^b10 is 20 or less.
In equation (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total number of carbon atoms of L ^b11 and L ^b12 is 21 or less.
In equation (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b15 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total number of carbon atoms of L ^b13 , L ^b14 and L ^b15 is 19 or less.
In equation (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total number of carbon atoms of L ^b16 , L ^b17 and L ^b18 is 19 or less. ]

L ^b8 is preferably an alkanediyl group having 1 to 4 carbon atoms.
L ^b9 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b10 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b16 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b17 is preferably a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b18 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

Examples of the formula (b1-3) include groups represented by the formulas (b1-9) to (b1-11), respectively.

[In equation (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
However, the total number of carbon atoms of L ^b19 and L ^b20 is 23 or less.
In equation (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
However, the total number of carbon atoms of L ^b21 , L ^b22 and L ^b23 is 21 or less.
In equation (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
^However, L ^b24, the total number of carbon atoms of ^{L b25} and ^{L b26} is 21 or less. ]

In formulas (b1-9) to (b1-11), when the hydrogen atom contained in the saturated hydrocarbon group is substituted with an acyloxy group, the number of carbon atoms of the acyloxy group, CO and O in the ester bond The number of carbon atoms of the saturated hydrocarbon group is taken into consideration, including the number of carbon atoms of the saturated hydrocarbon group.

Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group, an adamantylcarbonyloxy group and the like.
Examples of the acyloxy group having a substituent include an oxoadamantylcarbonyloxy group, a hydroxyadamantylcarbonyloxy group, an oxocyclohexylcarbonyloxy group, a hydroxycyclohexylcarbonyloxy group and the like.

Among the groups represented by the formula (b1-1), examples of the groups represented by the formula (b1-4) include the following.

Among the groups represented by the formula (b1-1), examples of the groups represented by the formula (b1-5) include the following.

Among the groups represented by the formula (b1-1), examples of the groups represented by the formula (b1-6) include the following.

Among the groups represented by the formula (b1-1), examples of the groups represented by the formula (b1-7) include the following.

Among the groups represented by the formula (b1-1), examples of the groups represented by the formula (b1-8) include the following.

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

Among the groups represented by the formula (b1-3), examples of the groups represented by the formula (b1-9) include the following.

Among the groups represented by the formula (b1-3), examples of the groups represented by the formula (b1-10) include the following.

Among the groups represented by the formula (b1-3), examples of the groups represented by the formula (b1-11) include the following.

L ^b1 preferably represents a divalent saturated hydrocarbon group (the methylene group contained in the saturated monovalent hydrogen group may be replaced with -O- or -CO-), and more preferably the formula (b1). It represents a group represented by -4) or a group represented by the formula (b1-2), L ^b4 is an alkanediyl group having 1 to 10 carbon atoms, and L ^b5 is a single bond, more preferably *. -CO-O- (CH ₂ ) _t (t represents an integer from 0 to 6. * represents the binding position to C (Q ¹ ) (Q ² )) or * -CH _2- O-CO -Represents (* represents the binding position to C (Q ¹ ) (Q ² )).

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

Examples of the other anion of the salt (I) include an anion represented by the above formula (IA), another sulfonic acid anion, a sulfonylimide anion, a sulfonylmethide anion, a carboxylic acid anion and the like. The other anion of the formula (I) is preferably a sulfonic acid anion, more preferably an anion represented by the formula (IA) or an anion represented by the formula (IA).
The anion in the salt (I) may be the same anion represented by the formula (IA) or a different anion represented by the formula (IA). Further, the anion in the salt (I) may be a combination of an anion represented by the formula (IA) and another sulfonic acid anion, a sulfonylimide anion, a sulfonylmethide anion or a carboxylic acid anion different from this. Alternatively, it may be a combination of an anion represented by the formula (IA) and an anion represented by the formula (IA).

[In formula (IA),
Q ^{1, Q 2} and ^{L b1} are the same as defined above.
Y represents a methyl group which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and is contained in the alicyclic hydrocarbon group. CH ₂ - is, -O -, - SO ₂ - or -CO- may be replaced with. ]
Q ^{1, Q 2} and illustrated and preferred ones ^{L b1} is also the same as above (the same in the present application).

Examples of the alicyclic hydrocarbon group of Y include groups represented by the formulas (Y1) to (Y11).
As the group in which -CH _2- contained in the alicyclic hydrocarbon group of Y is replaced with -O-, -SO _2- or -CO-, the groups represented by the formulas (Y12) to (Y27) are used. Can be mentioned.

It is preferably a group represented by any of the formulas (Y1) to (Y19), and more preferably a group represented by the formula (Y11), the formula (Y14), the formula (Y15) or the formula (Y19). Yes, more preferably a group represented by the formula (Y11) or the formula (Y14).

As the substituent of the methyl group of Y, a halogen atom, a hydroxy group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, a glycidyloxy group or-(CH ₂ ). _ja- O-CO-R ^b1 group (in the formula, R ^b1 is an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. (Ja represents an integer of 0 to 4) and the like.
As the substituent of the alicyclic hydrocarbon group of Y, a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkyl group containing a hydroxy group having 1 to 12 carbon atoms, and an alicyclic group having 3 to 16 carbon atoms A hydrocarbon group, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group or-(CH). _{2) niv} in ^{_{'-O-CO-R b1'}} group (wherein, ^{R b1 'is} an alkyl group having 1 to 16 carbon atoms, 3 to 16 carbon atoms alicyclic hydrocarbon group or having 6 to 18 carbon atoms It represents an aromatic hydrocarbon group. Ja'represents an integer from 0 to 4) and the like.

Examples of the hydroxy group-containing alkyl group include a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
The aromatic hydrocarbon group includes a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group; a trill group, a xylyl group, a cumenyl group, a mesityl group and a biphenyl group. Examples thereof include an aryl group such as a group, a phenanthryl group, a 2,6-diethylphenyl group and 2-methyl-6-ethylphenyl.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group and a naphthylethyl 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 Y include the following.

When Y is an alkyl group and L ^b1 is a divalent linear or branched saturated hydrocarbon group having 1 to 17 carbon atoms, the divalent saturated hydrocarbon at the bonding position with Y. It is preferable that the -CH _{2- of the} group is replaced with -O- or -CO-. In this case, -CH ₂ contained in the alkyl group Y - ^of, -CH ₂ in the coupling position of the ^{L b1} - is not Okikawara by -O- or -CO-.

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, and constitutes these groups. -CH _2- may be replaced with -O-, -SO _2- or -CO-. Y is even more preferably an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group.

Examples of the anion represented by the formula (IA) include anions represented by the formulas (IA-1) to (IA-29) [hereinafter, "anion (IA)" according to the formula number. -1) ”and so on. ] Are preferable, and formulas (IA-1) to (IA-4), formulas (IA-9), formulas (IA-10), formulas (IA-24) to formulas (IA-24) to formulas. The anion represented by any of (IA-29) is more preferable. Further, R ^{i2 to} R ⁱ⁴ in the formulas (IA-1) to (IA-29) represent alkyl groups having 1 to 4 carbon atoms independently of each other, and are preferably methyl groups. L ⁴ is a single bond or an alkanediyl group having 1 to 4 carbon atoms. Q ¹ and ^{Q 2} are the same as defined above.

Specifically, as the anion represented by the formula (IA), the anions represented by the formulas (Ia-1) to (Ia-11) are preferable.

Examples of the sulfonylimide anion include the following.

Other anions of the formula (I) include formulas (Ia-1) to (Ia-3) and formulas (Ia-7) to (Ia) in addition to the anions represented by the above formula (IA). The anion represented by any one of -11) is preferable.

The salt (I) of the present invention is a salt having a cation represented by the formula (IC).
[In the formula (IC),
R ¹ and R ² independently represent a hydrogen atom, a hydroxy group, or a hydrocarbon group having 1 to 12 carbon atoms, and −CH ₂ − contained in the hydrocarbon group is −O− or −CO−. It may be replaced.
m and n represent 1 or 2 independently of each other. when m is 2, two R ¹ may be the same or different, when n is 2, the two R ² may be the same or different.
Ar ¹ and Ar ² are independently of each other, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic aromatic group having 6 to 36 carbon atoms which may have a substituent. Represents a hydrocarbon group. ]

Examples of the hydrocarbon group of R ¹ and R ² include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups.
As the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, 2 Examples thereof include -ethylhexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group and the like.
The alicyclic hydrocarbon group may be either a monocyclic group or a polycyclic group, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and a methylcyclohexyl group. , Cycloalkyl group such as dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group, cyclodecyl group and the like. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, and a norbornyl group. Examples thereof include a methylnorbornyl group and an isobornyl group.
Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group.
Examples of the group formed by the combination include an aralkyl group, a benzyl group, a phenethyl group and the like.
The groups in which -CH _2- contained in the hydrocarbon group is replaced with -O- or -CO- include a methoxy group, an ethoxy group, a butoxy group, an acetyl group, a methoxycarbonyl group, an acetyloxy group, and a butoxycarbonyloxy group. , Benoxyloxy group and the like.

The aromatic hydrocarbon groups of Ar ¹ and Ar ² include phenyl group, naphthyl group, anthryl group, phenanthonyl group, trill group, xsilyl group, cumyl group, dimethylphenyl group, trimethylphenyl group, ethylphenyl group and propylphenyl group. , Butylphenyl group, biphenyl group, triphenyl group, indenyl group, tetrahydronaphthyl group, p-adamantylphenyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc. Included are ~ 36 aryl groups.
Examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom.
Examples of the heteroaromatic hydrocarbon group include a frill group and a thiophenyl group.
The aromatic hydrocarbon group or heteroaromatic hydrocarbon group preferably has 6 to 24 carbon atoms, and more preferably 6 to 18 carbon atoms.

Examples of the substituent of the aromatic hydrocarbon group and the heteroaromatic hydrocarbon group include a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alkylcarbonyloxy group having 2 to 18 carbon atoms, and an arylcarbonyloxy group having 7 to 18 carbon atoms. Examples thereof include a group or an alkoxycarbonyloxy group having 2 to 18 carbon atoms, and −CH ₂ − contained in the alkoxy group having 1 to 12 carbon atoms may be replaced with −O−. It is preferably a hydroxy group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group. It is preferably an alkoxy group having 1 to 6 carbon atoms, and more preferably a methoxy group.
Examples of the alkylcarbonyloxy group include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group, Examples thereof include pentylcarbonyloxy group, hexylcarbonyloxy group, octylcarbonyloxy group and 2-ethylhexylcarbonyloxy group. It is preferably an alkylcarbonyloxy group having 2 to 12 carbon atoms, and more preferably a methylcarbonyloxy group.
Examples of the arylcarbonyloxy group include a phenylcarbonyloxy group and a tosylcarbonyloxy group. It is preferably an arylcarbonyloxy group having 7 to 12 carbon atoms, and more preferably a phenylcarbonyloxy group.
Examples of the alkoxycarbonyloxy group include methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, isopropoxycarbonyloxy group, n-butoxycarbonyloxy group, sec-butoxycarbonyloxy group and tert-butoxycarbonyloxy group. , Pentyloxycarbonyloxy group, hexyloxycarbonyloxy group, octyloxycarbonyloxy group, 2-ethylhexyloxycarbonyloxy group and the like. It is preferably an alkyloxycarbonyloxy group having 2 to 8 carbon atoms, and more preferably a tert-butyloxycarbonyloxy group.

m is preferably 2.
n is preferably 2.
It is preferable that at least one of m and n is 2, and it is more preferable that both m and n are 2.
R ¹ is preferably a hydrogen atom.
R ² is preferably a hydrogen atom.
It is preferable that both R ¹ and R ² are hydrogen atoms.
Of Ar ¹ and Ar ² , at least one is preferably an aromatic hydrocarbon group which may have a substituent, and both Ar ¹ and Ar ² may have a substituent. It is more preferably a hydrogen group. It is preferable that Ar ¹ and Ar ² are the same.

Examples of the cation (IC) include the following cations and the like.

Examples of the cation (I) include formula (I-c-1), formula (I-c-3), formula (I-c-4), formula (I-c-7), and formula (I-c-12). ), Formula (I-c-14), formula (I-c-16) and cations represented by formula (I-c-22) are preferred.

As the salt, the above-mentioned anions and cations can be arbitrarily combined.
Examples of the salt (I) include the following salts.

<Manufacturing method of salt (I)>
The salt (I) composed of the anion represented by the formula (IA), the anion represented by A, and the cation represented by the formula (IC) is the salt represented by the formula (IA) and the formula (Ia). It can be produced by reacting with the compound represented by Ib) in a solvent in the presence of a catalyst.
[In the formula, Q ¹ , Q ² , L ^{b 1} , W, R ¹ , R ² , Ar ¹ , Ar ² , m, n, X ^a , X ^b and X ¹ have the same meanings as above.
A represents an anion. ]

Examples of the acid catalyst in this reaction include p-toluenesulfonic acid and the like.
Examples of the solvent in this reaction include chloroform, acetonitrile, dimethylformamide and the like.
Examples of the compound represented by the formula (I-b) include 2,2,3,3-tetrafluoro-1,4-butanediol, which can be easily obtained from the market.

The salt represented by the formula (Ia) is obtained by reacting the salt represented by the formula (Ic) with the salt represented by the formula (Id) in a solvent in the presence of a catalyst. Can be manufactured.
[In the formula, Q ¹ , Q ² , L ^{b 1} , W, R ¹ , R ² , Ar ¹ , Ar ² , m, n and A are synonymous with the above. ]

Examples of the catalyst include copper acetate (II) and the like.
Examples of the solvent include chloroform and the like.

Examples of the salt represented by the formula (Id) include salts represented by the following formula.

The salt (Ic) can be produced by reacting a salt represented by the formula (Ie) with a salt represented by the formula (If) in a solvent in the presence of a catalyst.
[In the formula, R ¹ , R ² , Ar ¹ and A ⁻ , m and n have the same meanings as described above. ]

Examples of the catalyst include copper acetate (II) and the like.
Examples of the solvent include chloroform and the like.

Examples of the salt represented by the formula (I-e) include salts represented by the following formula.

Examples of the compound represented by the formula (If) include compounds represented by the following formula.

<Acid generator>
The salt (I) can act as an acid generator, for example, in a resist composition. The acid generator generates an acid by exposure, and the generated acid acts catalytically to, for example, desorb a group desorbed by the acid of the resin (A) described later.
The acid generator of the present invention may contain the salt (I) alone, or may be referred to as a salt (I) and an acid generator known in the resist field (hereinafter referred to as an acid generator (B)). In some cases.) And may be contained. In the acid generator, the salt (I) may contain two or more kinds, and the acid generator (B) may contain two or more kinds.
When the acid generator contains the acid generator (B), the ratio of the content of the salt (I) to the acid generator (B) in the acid generator (mass ratio; salt (I): acid generator ( B)) is usually 1:99 to 100: 0, preferably 1:99 to 99: 1, more preferably 2:98 to 98: 2, and even more preferably 5:95 to 95 :. It is 5.

<Acid generator (B)>
The acid generator (B) is classified into a non-ionic type and an ionic type, and any of them may be used.
Nonionic acid generators include organic halides, sulfonate esters (eg 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones. (For example, disulfone, ketosulfone, sulfonyldiazomethane) and the like are included. The ionic acid generator is typically an onium salt containing an onium cation (for example, a diazonium salt, a phosphonium salt, a sulfonium salt, or an iodonium salt). Examples of the onium salt anion include a sulfonic acid anion, a sulfonylimide anion, and a sulfonylmethide anion.

Examples of the acid generator (B) include Japanese Patent Application Laid-Open No. 63-26653, Japanese Patent Application Laid-Open No. 55-164824, Japanese Patent Application Laid-Open No. 62-69263, Japanese Patent Application Laid-Open No. 63-146038, and Japanese Patent Application Laid-Open No. 63-163452. Kaisho 62-153853, Japanese Patent Application Laid-Open No. 63-146029, US Pat. No. 3,779,778, US Pat. No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712. Etc., a compound that generates an acid by radiation can be used. Moreover, you may use the compound produced by the known method.

The acid generator (B) is preferably a fluorine-containing acid generator, and more preferably a salt represented by the formula (B1) (hereinafter, may be referred to as “acid generator (B1)”).
[In equation (B1),
^{Q 1,} Q 2, ^{L b1} and Y represent the same meaning as ^{Q 1, Q 2, L b1,} Y in formula (I-A).
Z ⁺ represents an organic cation. However, Z ⁺ does not include the cation represented by the formula (IC). ]

Examples of the anion in the formula (B1) include the same anion as the anion represented by the formula (IA).
Z ⁺ is preferably an organic sulfonium cation.
Specific examples thereof include salts represented by any of the formulas (B1-1) to (B1-32). Of these, those containing an arylsulfonium cation are preferable, and formulas (B1-1), formulas (B1-2), formulas (B1-3), formulas (B1-6), formulas (B1-7), and formulas (B1-11) are preferable. ), Equation (B1-12), Equation (B1-13), Equation (B1-14), Equation (B1-20), Equation (B1-21), Equation (B1-22), Equation (B1-23). , Formula (B1-24), formula (B1-25), formula (B1-26), formula (B1-29), formula (B1-31) or salt represented by formula (B1-32). Is more preferable.

<Resist composition>
The resist composition of the present invention contains an acid generator and a resin having an acid unstable group (hereinafter, may be referred to as "resin (A)"). Here, the "acid-unstable group" is a structural unit having a leaving group, the leaving group being removed by contact with an acid, and the constituent unit having a hydrophilic group (for example, a hydroxy group or a carboxy group). Means the group that converts to.
As the acid generator, the above-mentioned acid generator can be used.
The resist composition preferably further contains a citrine (hereinafter sometimes referred to as "quencher (C)") and / or a solvent (hereinafter sometimes referred to as "solvent (E)").

<Acid generator>
In the resist composition, the content of the acid generator is preferably 1.5% by mass or more, more preferably 3% by mass or more, preferably 40% by mass or less, more preferably more preferably, with respect to the resin (A). It is 35% by mass or less. For example, it is preferably 1 to 40% by mass, more preferably 2 to 35% by mass, and even more preferably 3 to 35% by mass.
In particular, when only the salt (I) is used as the acid generator, the content of the salt (I) is preferably 1 to 40% by mass, preferably 2 to 35% by mass, based on the resin (A). More preferably.

<Resin (A)>
The resin (A) has a structural unit having an acid unstable group (hereinafter, may be referred to as “structural unit (a1)”). The resin (A) preferably further contains a structural unit other than the structural unit (a1). Examples of the structural unit other than the structural unit (a1) include a structural unit having no acid-labile group (hereinafter, may be referred to as “structural unit (s)”).

<Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid unstable group (hereinafter, may be referred to as “monomer (a1)”).
The acid unstable group contained in the resin (A) is preferably a group (1) and / or a group (2).

[In the formula (1), R ^{a1 to} R ^a3 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group combining these groups, or R. ^a1 and ^Ra2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
na represents 0 or 1.
* Represents a bond. ]

Wherein (2), ^{R a1 'and R a2'} independently of one another, represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, ^{R a2 'is} a hydrocarbon group having 1 to 20 carbon atoms Represented, R ^a2'and R ^a3' are bonded to each other to form a divalent heterocyclic group having 3 to 20 carbon atoms together with the carbon atom and X to which they are bonded, and the hydrocarbon group and the divalent complex. The −CH ₂₋ contained in the ring group may be replaced by −O− or −S−.
X represents an oxygen atom or a sulfur atom.
* Represents a bond. ]

^Examples of the alkyl group of R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group and the like.
The alicyclic hydrocarbon groups of R ^{a1 to} R ^a3 may be either 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 (* indicates a bond). The alicyclic hydrocarbon groups of R ^{a1 to} R ^a3 are preferably alicyclic hydrocarbon groups having 3 to 16 carbon atoms.

Examples of the group in which the alkyl group and the alicyclic hydrocarbon group are combined include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, a norbornylethyl group and the like. Can be mentioned.
na is preferably 0.

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 alicyclic hydrocarbon group include the following groups. The divalent alicyclic 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 (a group in which R ^{a1 to} R ^a3 are alkyl groups in the formula (1), preferably a tert-butoxycarbonyl group), 2-. Alkyl adamantan-2-yloxycarbonyl group (in formula (1), Ra ¹ , Ra ² and the carbon atom to which they are bonded form an adamantyl group, and Ra ³ is an alkyl group) and 1- (adamantan-). 1-yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups and R ^a3 is an adamantyl group) and the like.

Examples of the hydrocarbon group R ^{a1 '~R a3',} an alkyl group, an alicyclic hydrocarbon group, and a group formed by combining an aromatic hydrocarbon group and thereof.
Examples of the alkyl group and the alicyclic hydrocarbon group include the same as above.
The aromatic hydrocarbon group includes a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a trill group, a xsilyl group, a cumenyl group, a mesityl group and a biphenyl group. Examples thereof include an aryl group such as a group, a phenanthryl group, a 2,6-diethylphenyl group and a 2-methyl-6-ethylphenyl group.
^{Examples of the} divalent heterocyclic group formed by R ^a2'and R ^a3'bonding to each other together with the carbon atom and X to which they are bonded include the following groups. * Represents a bond.

Of R ^{a1 'and R a2',} it is preferable that at least one is a hydrogen atom.

Specific examples of the groups represented by the formula (2) include the following groups. * Represents a bond.

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

Among the (meth) acrylic monomers having an acid unstable 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 the structural unit derived from the (meth) acrylic monomer having a group represented by the formula (1), the structural unit represented by the formula (a1-0) is preferably represented by the formula (a1-1). Examples thereof include a structural unit or a structural unit represented by the formula (a1-2). These may be used alone or in combination of two or more. In the present specification, the structural unit represented by the formula (a1-0), the structural unit represented by the formula (a1-1), and the structural unit represented by the formula (a1-2) are each structural unit (a1). −0), structural unit (a1-1) and structural unit (a1-2), monomer for inducing structural unit (a1-0), monomer for inducing structural unit (a1-1) and structural unit (a1-) The monomer that induces 2) may be referred to as a monomer (a1-0), a monomer (a1-1), and a monomer (a1-2), respectively.

[In equation (a1-0),
L ^a01 represents an oxygen atom or _{* -O- (CH 2) k01 -CO} -O- the stands, k01 represents an integer of 1-7, * represents a bond to a carbonyl group.
R ^a01 represents a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 independently ^represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these groups. ]

[In the formula (a1-1) and the formula (a1-2),
L ^a1 and L ^a2 independently represent -O- or * -O- (CH ₂ ) _k1- CO-O-, k1 represents an integer of 1 to 7, and * represents a combination with -CO-. Represent a hand.
R ^a4 and R ^a5 represent a hydrogen atom or a methyl group independently of each other.
R ^a6 and R ^a7 represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining them independently of each other.
m1 represents an integer from 0 to 14.
n1 represents an integer from 0 to 10.
n1'represents an integer from 0 to 3. ]

^La01 is preferably an oxygen atom or * -O- (CH ₂ ) _k01- CO-O- (where k01 is preferably an integer of 1 to 4, more preferably 1), more preferably. Is an oxygen atom.
Examples of the alkyl group of R ^a02 , R ^a03 and R ^a04 , the alicyclic hydrocarbon group and the group in which these are combined include the same groups as those mentioned in Ra ¹ to Ra ³ of the formula (1).
The number of carbon atoms of the alkyl groups of R ^a02 , R ^a03 and R ^a04 is preferably 6 or less.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 and R ^a04 have preferably 8 or less carbon atoms, more preferably 6 or less carbon atoms.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in combination of these alkyl groups and the alicyclic hydrocarbon group. Examples of such a group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a methyladamantyl group, a cyclohexylmethyl group, a methylcyclohexylmethyl group, an adamantylmethyl group, a norbornylmethyl group and the like. Be done.
R ^a02 and R ^a03 are preferably alkyl groups having 1 to 6 carbon atoms, and more preferably methyl groups or ethyl groups.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group.

^La1 and ^La2 are preferably −O− or * −O− (CH ₂ ) _{k1 ′} −CO−O− (where k1 ′ is an integer of 1 to 4, preferably 1). ), More preferably -O-.
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 combining these groups include the same groups as those listed in R ^{a1 to} R ^a3 of the formula (1).
The alkyl group of R ^a6 and R ^a7 has preferably 6 or less carbon atoms.
The alicyclic hydrocarbon groups of R ^a6 and R ^a7 have preferably 8 or less carbon atoms, and more preferably 6 or less carbon atoms.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, and more preferably 0 or 1.
n1'is preferably 0 or 1.

As the structural unit (a1-0), for example, a structural unit represented by any of the formulas (a1-0-1) to (a1-0-12) is preferable, and the structural units (a1-0-1) to The structural unit represented by any of the formulas (a1-0-10) is more preferable.

In the above structural units, structural units in which a methyl group is replaced by a hydrogen atom corresponding to R ^a01 may be mentioned as specific examples of the structural units (a1-0).

Examples of the monomer (a1-1) include the monomers described in JP-A-2010-204646. Among them, the monomers represented by any of the formulas (a1-1-1) to (a1-1-8) are preferable, and any one of the formulas (a1-1-1) to (a1-1-4) is preferable. The monomer represented by is more preferable.

Examples of the monomer (a1-2) include 1-methylcyclopentane-1-yl (meth) acrylate, 1-ethylcyclopentane-1-yl (meth) acrylate, and 1-methylcyclohexane-1-yl (meth). Acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, 1-ethylcycloheptan-1-yl (meth) acrylate, 1-ethylcyclooctane-1-yl (meth) acrylate, 1-isopropylcyclopentane-1 -Il (meth) acrylate, 1-isopropylcyclohexane-1-yl (meth) acrylate and the like can be mentioned. Monomers represented by any of formulas (a1-2-1) to (a1-2-12) are preferable, and formulas (a1-2-3), formulas (a1-2-4), and formulas (a1-) are preferable. The monomers represented by 2-9) and the formula (a1-2-10) are more preferable, and the monomers represented by the formulas (a1-2-3) and the formula (a1-2-9) are further preferable.

When the resin (A) contains a structural unit (a1-0) and / or a structural unit (a1-1) and / or a structural unit (a1-2), the total content of these is the total structure of the resin (A). It is usually 10 to 95 mol%, preferably 15 to 90 mol%, and more preferably 20 to 85 mol% with respect to the total of units.

Further, as the structural unit (a1) having the group (1), a structural unit represented by the formula (a1-3) can also be mentioned. The structural unit represented by the formula (a1-3) may be referred to as a structural unit (a1-3). Further, the monomer for inducing the structural unit (a1-3) may be referred to as a monomer (a1-3).
[In equation (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 .
Ra ¹³ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group formed by combining these groups, and the aliphatic hydrocarbon group and the group. The hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group, and the aliphatic hydrocarbon group and −CH ₂ − contained in the alicyclic hydrocarbon group are −O−. Alternatively, it may be replaced with −CO−.
R ^a10 , R ^a11 and R ^a12 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group formed by combining them. R ^a10 and R ^a11 bond with each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. ]

Here, -COOR ^a13 includes, for example, 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 of R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group and a 2-hydroxyethyl group.
^Examples of the aliphatic hydrocarbon group having 1 to 8 carbon atoms of R ^a13 include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group and n. -Hexyl group, n-heptyl group, 2-ethylhexyl group, n-octyl group and the like can be mentioned.
^Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms of Ra ¹³ include a cyclopentyl group, a cyclopropyl group, an adamantyl group, an adamantyl methyl group, a 1-adamantyl-1-methylethyl group, and a 2-oxo-oxolane-3-3. Examples thereof include an yl group and a 2-oxo-oxolan-4-yl group.
Alkyl groups of R ^{a10 to} R ^a12 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, and the like. Examples thereof include an n-heptyl group, a 2-ethylhexyl group and an n-octyl group.
The alicyclic hydrocarbon groups of R ^{a10 to} R ^a12 may be monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon groups include, for example, a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group. , Cycloalkyl groups such as cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group, cyclodecyl group and the like. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, and a norbornyl group. Examples thereof include a group, a methylnorbornyl group and an isobornyl group.
As -C (R ^a10 ) (R ^a11 ) (R ^a12 ) when R ^a10 and R ^a11 are bonded to each other to form a divalent alicyclic hydrocarbon group together with the carbon atom to which they are bonded. , The following groups are preferred.

Specifically, the monomer (a1-3) is 5-norbornene-2-carboxylic acid-tert-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, 5-norbornene-2-carboxylic acid. 1-Methylcyclohexyl acid, 2-methyl-2-adamantyl 5-norbornen-2-carboxylic acid, 2-ethyl-2-adamantyl 5-norbornen-2-carboxylic acid, 1- (4) 5-norbornen-2-carboxylic acid -Methylcyclohexyl) -1-methylethyl, 5-norbornen-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornen-2-carboxylic acid 1-methyl-1- (4-oxo) Cyclohexyl) ethyl and 5-norbornen-2-carboxylic acid 1- (1-adamantyl) -1-methylethyl and the like can be mentioned.

Since the resin (A) containing the structural unit (a1-3) contains a three-dimensionally bulky structural unit, it is higher than the resist composition of the present invention containing such a resin (A). The resist pattern can be obtained at the resolution. Further, since a rigid norbornane ring is introduced into the main chain, the obtained resist pattern tends to have excellent dry etching resistance.

When the resin (A) contains structural units (a1-3), the content thereof is preferably 10 to 95 mol% with respect to the total of all structural units of the resin (A), and 15 to 90 mol%. It is more preferably%, and further preferably 20 to 85 mol%.

As the structural unit (a1) having a group represented by the group (2), the structural unit represented by the formula (a1-4) (hereinafter, may be referred to as “structural unit (a1-4)”). Can be mentioned.
[In equation (a1-4),
Ra ³² 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 the like. Represents a methacryloyloxy group.
la represents an integer from 0 to 4. When la is 2 or more, the plurality of Ra ^33s may be the same or different from each other.
R ^a34 and ^{R a35} are independently of each other, represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon ^{atoms, R a36} may represent a hydrocarbon group having 1 to 20 carbon ^{atoms, R a35} and ^{R a36} are each A divalent heterocyclic group having 3 to 20 carbon atoms is formed together with the CO to which they are bonded, and the hydrocarbon group and -CH _2- contained in the divalent heterocyclic group are -O. It may be replaced by − or −S−. ]

^Examples of the alkyl group of 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 even more preferably a methyl group.
Examples of the halogen atom of R ^a32 and R ^a33 include a fluorine atom, a chlorine atom and a bromine atom.
Examples of the alkyl group that may have a halogen atom include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group, and 1,1,2,2-tetrafluoro. Ethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3,4,4-octafluoro Butyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, n-pentyl group, n-hexyl group, n-perfluorohexyl group, etc. Can be mentioned.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Of these, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is even more preferable.
Examples of the acyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group and the like.
Examples of the hydrocarbon group R ^a34 and ^{R a35,} include the same groups as ^{R a1 'and R a2'} of formula (2).
R ^a36 includes 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 group formed by combining these groups. Can be mentioned.

In the formula (a1-4), Ra ³² is preferably a hydrogen atom.
R ^a33 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group and an ethoxy group, and even more preferably a methoxy group.
la is preferably 0 or 1, more preferably 0.
^Ra34 is preferably a hydrogen atom.
R ^a35 is preferably a hydrocarbon group having 1 to 12 carbon atoms, and more preferably a methyl group or an ethyl group.
The hydrocarbon group of 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. Examples thereof include an alkyl group having 1 to 18 carbon atoms, an alicyclic aliphatic hydrocarbon group having 3 to 18 carbon atoms, and an aralkyl group having 7 to 18 carbon atoms.
The alkyl group and the alicyclic hydrocarbon group in ^Ra36 are preferably unsubstituted.
When the aromatic hydrocarbon group in ^Ra36 has a substituent, an aryloxy group having 6 to 10 carbon atoms is preferable as the substituent.

Examples of the monomer for deriving the structural unit (a1-4) include the monomers described in JP-A-2010-204646. Among them, the monomers represented by the formulas (a1-4-1) to (a1-4-8) are preferable, and the formulas (a1-4-1) to (a1-4-5) and the formula (a1-) are preferable. The monomers represented by 4-8) are more preferable.

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

The structural unit derived from the (meth) acrylic monomer having a group represented by the formula (2) is a structural unit represented by the formula (a1-5) (hereinafter referred to as “structural unit (a1-5)”). There is).
[In equation (a1-5),
R ^a8 represents an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom which may have a halogen atom.
Z ^a1 represents a single bond or _{* - (CH 2) h3 -CO} -L 54 - represents, h3 represents an integer of 1 to 4, * ^represents a bond to ^{L 51.}
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ independently represent −O− or −S−.
s1 represents an integer of 1 to 3.
s1'represents an integer from 0 to 3. ]

Examples of the halogen atom include a fluorine atom and a chlorine atom, and preferably a fluorine atom.
Alkyl groups having 1 to 6 carbon atoms which may have a halogen atom include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, fluoromethyl group and trifluoromethyl. Group is mentioned.
In the formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
Of L ⁵² and L ⁵³ , it is preferable that one is −O− and the other is −S−.
s1 is preferably 1.
s1'is preferably an integer of 0-2.
Z ^a1 is preferably a single bond or * -CH _2- CO-O-.

Examples of the monomer for deriving the structural unit (a1-5) include the monomers described in JP-A-2010-61117. Among them, the monomers represented by the formulas (a1-5-1) to (a1-5-2) are preferable, and the monomers represented by the formula (a1-5-1) or the formula (a1-5-2) are preferable. Is more preferable.

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

The structural unit (a) having an acid unstable group in the resin (A) includes a structural unit (a1-0), a structural unit (a1-1), a structural unit (a1-2), and a structural unit (a1-5). At least one or more selected from the group consisting of) is preferable, at least two or more are more preferable, and a combination of structural units (a1-1) and structural units (a1-2), structural units (a1-1) and structural units (a1-1) Combination of a1-5), combination of structural unit (a1-1) and structural unit (a1-0), combination of structural unit (a1-2) and structural unit (a1-0), structural unit (a1-5) And a combination of structural units (a1-0), structural units (a1-0), structural units (a1-1) and structural units (a1-2), structural units (a1-0), structural units (a1-). The combination of 1) and the structural unit (a1-5) is more preferable, and the combination of the structural unit (a1-1) and the structural unit (a1-2), the structural unit (a1-1) and the structural unit (a1-5) The combination is even more preferred.
The structural unit (a1) preferably includes the structural unit (a1-1).

<Structural unit (s)>
The structural unit (s) is derived from a monomer having no acid-labile group (hereinafter, may be referred to as “monomer (s)”). As the monomer for deriving the structural unit (s), a monomer having no acid unstable group known in the field of resist can be used.
As the structural unit (s), a structural unit having a hydroxy group or a lactone ring and having no acid instability group is preferable. A structure having a hydroxy group and no acid instability group (hereinafter sometimes referred to as "structural unit (a2)") and / or a lactone ring and no acid instability group If a resin having a unit (hereinafter sometimes referred to as "structural unit (a3)") is used in the resist composition of the present invention, 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.
When a resist pattern is produced from the resist composition of the present invention, when a high-energy ray such as a KrF excimer laser (248 nm), an electron beam or EUV (ultraviolet light) is used as an exposure light source, the structural unit (a2) is used. , It is preferable to use the structural unit (a2) having a phenolic hydroxy group. When an ArF excimer laser (193 nm) or the like is used, the structural unit (a2) is preferably a structural unit (a2) having an alcoholic hydroxy group, and more preferably a structural unit (a2-1). As the structural unit (a2), one type may be contained alone, or two or more types may be included.

Examples of the structural unit (a2) having a phenolic hydroxy group include a structural unit represented by the formula (a2-0) (hereinafter, may be referred to as “structural unit (a2-0)”).
[In equation (a2-0),
R ^a30 represents an alkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, a halogen atom or 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 from 0 to 4. When ma is an integer of 2 or more, the plurality of Ra ^31s may be the same or different from each other. ]

^Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom of R ^a30 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group, and 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, n-pentyl group, n-hexyl Examples include a group and an n-perfluorohexyl group.
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 further preferably a hydrogen atom or a methyl group.
^Examples of the alkoxy group of ^Ra31 include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further preferable.
Examples of the acyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group and the like.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and even more preferably 0.

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

The resin (A) containing the structural unit (a2-0) undergoes a polymerization reaction using a monomer in which the phenolic hydroxy group of the monomer inducing the structural unit (a2-0) is protected with a protecting group, and then deprotected. It can be manufactured by processing. However, when performing the deprotection treatment, it is necessary to carry out the deprotection treatment so as not to significantly impair the acid unstable group of the structural unit (a1). Examples of such a protecting group include an acetyl group and the like.

When the resin (A) has a structural unit (a2-0) having a phenolic hydroxy group, the content thereof shall be 5 to 95 mol% with respect to the total of all the structural units of the resin (A). , More preferably 10 to 80 mol%, and even more preferably 15 to 80 mol%.

Examples of the structural unit (a2) having an alcoholic hydroxy group include a structural unit represented by the formula (a2-1) (hereinafter, may be referred to as “structural unit (a2-1)”).
[In equation (a2-1),
^La3 represents −O− or * −O− (CH ₂ ) _k2 −CO−O−.
k2 represents an integer of 1-7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 represent a hydrogen atom, a methyl group or a hydroxy group independently of each other.
o1 represents an integer from 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 -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, and more preferably 0 or 1.

Examples of the monomer for inducing the structural unit (a2-1) include the monomers described in JP-A-2010-204646. The monomer represented by any of the formulas (a2-1-1) to (a2-1-6) is preferable, and the monomer represented by any of the formulas (a2-1-1) to (a2-1-4) is represented. The monomer represented by the formula (a2-1-1) or the formula (a2-1-3) is more preferable.

When the resin (A) contains the structural unit (a2-1), the content thereof is usually 1 to 45 mol%, preferably 1 to 40 mol%, based on the total of all the structural units of the resin (A). %, More preferably 1 to 35 mol%, still more preferably 2 to 20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocyclic ring such as β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a fused ring of a monocyclic lactone ring and another ring. But it may be. Preferably, a γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing a γ-butyrolactone ring structure can be mentioned.

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). One of these may be contained alone, or two or more thereof may be contained.
[In equation (a3-1),
^La4 represents a group represented by −O− or ^* −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.
Ra ²¹ represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents an integer from 0 to 5. When p1 is 2 or more, the plurality of Ra ^21s may be the same or different from each other.
In equation (a3-2),
^La5 represents a group represented by −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
Ra ¹⁹ 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 from 0 to 3. When q1 is 2 or more, the plurality of Ra ^22s may be the same or different from each other.
In formula (a3-3),
^La6 represents a group represented by −O− or ^* −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 from 0 to 3. When r1 is 2 or more, the plurality of Ra ^23s may be the same or different from each other.
In formula (a3-4),
R ^a24 represents an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom which may have a halogen atom.
L ^a7 is a single bond, ^* -O-, ^* -O- L ^a8- O-, ^* -O- L ^a8- CO-O-, ^* -O- L ^a8- CO-O-L ^a9- CO- Represents O- or ^* -O- L ^a8- O-CO-L ^a9- O-.
* Represents a bond with a carbonyl group.
^La8 and ^La9 represent alkanediyl groups having 1 to 6 carbon atoms independently of each other. ]

The aliphatic hydrocarbon groups of R ^a21 , R ^a22 and R ^a23 include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group and tert-butyl group. Can be mentioned.
Examples of the halogen atom of ^Ra24 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
^Examples of the alkyl group of R ^a24 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group and an n-hexyl group. , Preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.
Alkyl groups 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 and perfluoro. Examples thereof include a hexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

The alkanediyl groups of ^La8 and ^La9 include 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, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, Examples thereof include 4-diyl group and 2-methylbutane-1,4-diyl group.

In the formula (a3-1) ~ formula ^(a3-3), L a4 ^{~L a6,} independently of one another, preferably -O- or, k3 is an integer of from 1 to 4 * -O- _(CH 2) A group represented by _k3- CO-O-, more preferably -O- 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 independent of each other, preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are independent of each other, preferably an integer of 0 to 2, and more preferably 0 or 1.

In formula (a3-4)
^Ra24 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 further preferably a hydrogen atom or a methyl group.
L ^a7 is preferably a single bond , ^* -O- or ^* -O- ^LA8- CO-O-, and more preferably a single bond, ^* -O-, ^* -O- CH _2- CO-. O- or ^* -O- C ₂ H _4- CO-O-.

Examples of the monomer for deriving the structural unit (a3) include the monomer described in JP-A-2010-204646, the monomer described in JP-A-2000-122294, and the monomer described in JP-A-2012-41274. Can be mentioned. The structural unit (a3) includes equations (a3-1-1) to (a3-1-4), equations (a3-2-1) to (a3-2-4), and equations (a3-3-3). 1) The structural unit represented by any of the formulas (a3-3-4) and the formulas (a3-4-1) to (a3-4-12) is preferable, and the formula (a3-1-1), It is represented by any of the formulas (a3-1-2), formulas (a3-2-3) to formulas (a3-2-4) and formulas (a3-4-1) to formulas (a3-4-12). The structural unit represented by any of the formulas (a3-4-1) to (a3-4-12) is more preferable, and the structural unit represented by any of the formulas (a3-4-1) to (a3-4-1) is more preferable. The structural unit represented by any of 4-6) is even more preferable.

In the following structural units, compounds methyl group corresponding to R ^a24 is replaced by a hydrogen atom, it may be mentioned as specific examples of the structural unit (a3-4).

When the resin (A) contains the structural unit (a3), the total content thereof is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on the total of all the structural units of the resin (A). It is more preferably 10 to 60 mol%.
Further, the contents of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3) and the structural unit (a3-4) are independent of each other, and the total structural unit of the resin (A). It is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, and even more preferably 10 to 50 mol% with respect to the total of.

<Other structural units (t)>
The resin (A) may contain other structural units (hereinafter, may be referred to as “structural unit (t)”) as structural units other than the structural unit (a1) and the structural unit (s). As the structural unit (t), 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)”) and a non-desorbed hydrocarbon group are used. Examples thereof include a structural unit (s) having a structure (hereinafter sometimes referred to as a “structural unit (a5)”). The resin (A) may have a structural unit other than the above-mentioned structural unit, and examples of such a structural unit include structural units well known in the art.

Examples of the structural unit (a4) include a structural unit represented by the formula (a4-0).
[In equation (a4-0),
R ⁵ represents a hydrogen atom or a methyl group.
L ⁵ represents a single bond or an aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.
L ³ represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms.
R ⁶ represents a hydrogen atom or a fluorine atom. ]

Examples of the aliphatic saturated hydrocarbon group of L ^5, include alkanediyl group having 1 to 4 carbon atoms, e.g., methylene group, ethylene group, propane-1,3-diyl, butane-1,4-diyl group Such as linear alkanediyl group, linear alkanediyl group having an alkyl group (particularly methyl group, ethyl group, etc.) side chain, ethane-1,1-diyl group, propane-1, Examples thereof include branched alkanediyl groups such as 2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.

The perfluoro alkanediyl group L ^3, difluoromethylene group, a perfluoroalkyl ethylene group, perfluoroethyl fluoro methylene group, perfluoro-1,3-diyl group, perfluoro-1,2-diyl group, perfluoropropane-2,2 -Diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane-2,2 -Diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane-1,7 -Diyl group, perfluoroheptane-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2 -Diyl group, perfluorooctane-3,3-diyl group, perfluorooctane-4,4-diyl group and the like can be mentioned.
Examples of the perfluorocycloalkanediyl group of L ³ include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, and a perfluoroadamantandiyl group.

L ⁵ is preferably a single bond, a methylene group or an ethylene group, and more preferably a single bond or a methylene group.
L ³ is preferably a perfluoroalkanediyl group having 1 to 6 carbon atoms, and more preferably a perfluoroalkanediyl group having 1 to 3 carbon atoms.

Examples of the structural unit (a4-0) include the structural units shown below.

Examples of the structural unit (a4) include a structural unit represented by the formula (a4-1).
[In equation (a4-1),
^Ra41 represents a hydrogen atom or a methyl group.
R ^a42 represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and -CH _2- contained in the hydrocarbon group may be replaced with -O- or -CO-. Good.
^Aa41 represents an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a group represented by the formula ( ^ag1 ). ]

[In the formula (ag1),
s represents 0 or 1.
A ^a42 and A ^a44 represent aliphatic hydrocarbon groups having 1 to 5 carbon atoms which may have substituents independently of each other.
A ^a43 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a single bond or a substituent.
X ^a41 and X ^a42 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 7 or less.
Of the two binding hands represented by *, the * on the right side is the binding hand with -O-CO-R ^a42 . ]

^Examples of the hydrocarbon group of R ^a42 include a chain type and a ring type aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups.
The chain-type and ring-type aliphatic hydrocarbon groups may have a carbon-carbon unsaturated bond, but chain-type and ring-type aliphatic saturated hydrocarbon groups are preferable. The aliphatic saturated hydrocarbon group is a fat formed by combining a linear or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an alkyl group and an alicyclic hydrocarbon group. Examples include group hydrocarbon groups.

The chain-type aliphatic hydrocarbon group includes methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group and n-decyl. Examples thereof include a group, an n-dodecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group and an n-octadecyl group. The cyclic aliphatic hydrocarbon group includes a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group; a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups (* is a bond). Examples thereof include polycyclic alicyclic hydrocarbon groups such as (representing a hand).

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.

The hydrocarbon group of R ^a42 is preferably a chain type or ring type aliphatic hydrocarbon group and a group formed by combining them, and may have a carbon-carbon unsaturated bond. , Chain-type and cyclic-type aliphatic saturated hydrocarbon groups, and groups formed by combining these groups are more preferable.
^Examples of the substituent of R ^a42 include a halogen atom or a group represented by the formula ( ^ag3 ). Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.

[In the formula (ag3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms having at least one halogen atom.
* Represents a bond. ]

^Examples of the aliphatic hydrocarbon group of A ^{a45 include} the same groups as those exemplified in Ra ⁴² .
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, and is an alkyl group having a halogen atom and / or an aliphatic hydrocarbon group having a group represented by the formula (ag3). Is more preferable.
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 further preferably having a carbon number of carbon. It is a perfluoroalkyl group of 1 to 6, and particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. 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.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula ( ^ag3 ), the aliphatic hydrocarbon includes the number of carbon atoms contained in the group represented by the formula (ag3). The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When the group represented by the formula (ag3) is used as a substituent, the number thereof is preferably one.

The aliphatic hydrocarbon group having a group represented by the formula (ag3) is more preferably a group represented by the formula (ag2).
[In the formula (ag2),
A ^a46 represents an aliphatic hydrocarbon group having 1 to 17 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 1 to 17 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.
* Represents a bond with a carbonyl group. ]

The number of carbon atoms of the aliphatic hydrocarbon group of A ^a46 is preferably 1 to 6, and more preferably 1 to 3.
The aliphatic hydrocarbon group of A ^a47 preferably has 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms, and further preferably A ^a47 is a cyclohexyl group or an adamantyl group.

A more preferable structure of the partial structure represented by * -A ^a46- X ^a44- A ^a47 is the following structure.

The alkanediyl group of A ^a41 includes a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group. Linear alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, etc. Examples thereof include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group of ^Aa41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an ^alcandiyl group having 1 to 4 carbon atoms, more preferably an ^alcandiyl group having 2 to 4 carbon atoms, and further preferably an ethylene group.

The aliphatic hydrocarbon groups A ^a42 , A ^a43 and A ^{a44 in} the group (a-g1) may have a carbon-carbon unsaturated bond, but an aliphatic saturated hydrocarbon group is preferable. As the aliphatic saturated hydrocarbon group, an alkyl group (the alkyl group may be linear or branched) and an alicyclic hydrocarbon group, and an alkyl group and an alicyclic hydrocarbon group are combined. Examples thereof include an aliphatic hydrocarbon group formed by. Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, Examples thereof include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
^Examples of the substituent of the aliphatic hydrocarbon group of A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably 0.

^Examples of the group ( ^{ag1) in} which X ^a42 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group include the following groups. In the following examples, * and ** represent the binding hand, respectively, and ** is the binding hand with -O-CO-R ^a42 .

As the structural unit represented by the formula (a4-1), the structural unit represented by the formula (a4-2) and the formula (a4-3) is preferable.
[In equation (a4-2),
R ^f01 represents a hydrogen atom or a methyl group.
A ^f01 represents an alkanediyl group having 1 to 6 carbon atoms.
R ^f02 represents a hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

The alkanediyl group of A ^f01 includes methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, and pentane-1,5-diyl group. , Hexine-1,6-diyl group and other linear alkanediyl groups; 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2 Examples thereof include branched alkanediyl groups such as −diyl group, 1-methylbutane-1,4-diyl group and 2-methylbutane-1,4-diyl group.

The hydrocarbon group of R ^f02 includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and the aliphatic hydrocarbon group includes a chain type, a cyclic type and a group formed by a combination thereof. As the aliphatic hydrocarbon group, an alkyl group and an alicyclic hydrocarbon group are preferable.
Alkyl groups 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, n-octyl group and 2 -Ethylhexyl group is mentioned.
The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cycloheptyl group, a cyclodecyl group and the like. Cycloalkyl groups can be mentioned. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, and a norbornyl group. Examples thereof include a methylnorbornyl group and an isobornyl group.

Examples of the hydrocarbon group having a fluorine atom of R ^f02 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
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, a 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, 1- (trifluoromethyl) -2,2,2-trifluoroethyl 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- (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, 2- (perfluorobutyl) ethyl group, 1 , 1,2,2,3,3,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,5,5,6,6-dodecafluoro Fluoroalkyl groups such as hexyl groups, perfluoropentylmethyl groups and perfluorohexyl groups can be mentioned.
Examples of the alicyclic hydrocarbon group having a fluorine atom include a cycloalkyl fluoride group such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

A ^f01 in the formula (a4-2) is preferably an alkanediyl group having 2 to 4 carbon atoms, and more preferably an ethylene group.
R ^f02 is preferably an alkyl fluoride group having 1 to 6 carbon atoms.

[In equation (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 of A ^f11 include the same groups as the alkanediyl group of A ^f1 .

The aliphatic hydrocarbon group of A ^f13 includes a chain type and a ring type aliphatic hydrocarbon group, and a divalent aliphatic hydrocarbon group formed by combining them. This aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
The 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, and more preferably a perfluoroalkanediyl group.
Examples of the divalent chain aliphatic hydrocarbon group which may have a fluorine atom include an alkandiyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentangyl group; a difluoromethylene group and a perfluoroethylene group. Examples thereof include a perfluoroalkandyl group such as a group, a perfluoropropanediyl group, a perfluorobutandyl group and a perfluoropentandyl group.
The divalent cyclic aliphatic hydrocarbon group which may have a fluorine atom may be a group containing either a monocyclic or polycyclic group. 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 adamantandiyl group, a norbornanediyl group, and a perfluoroadamantandiyl group.

The aliphatic hydrocarbon group of A ^f14 includes a chain type and a ring type aliphatic hydrocarbon group, and an aliphatic hydrocarbon group formed by combining them. This aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
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-type 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 and 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, pentyl group, hexyl group, perfluorohexyl group, Examples thereof include a heptyl group, a perfluoroheptyl group, an octyl group and a perfluorooctyl group.
The cyclic aliphatic hydrocarbon group which may have a fluorine atom may be either 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 adamantyl methyl group, a norbornyl group, a norbornyl methyl group, a perfluoroadamantyl group, a perfluoroadamantyl methyl group and the like.

In the formula ^{(a4-3), A f11} is preferably an ethylene group.
The aliphatic hydrocarbon group of A ^f13 is preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, and more preferably an aliphatic hydrocarbon group having 2 to 3 carbon atoms.
The aliphatic hydrocarbon group of A ^f14 is preferably an aliphatic hydrocarbon group having 3 to 12 carbon atoms, and more preferably an aliphatic hydrocarbon group having 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 structural unit represented by the formula (a4-2) include the structural units represented by the formulas (a4-1-1) to (a4-1-22).

Examples of the structural unit represented by the formula (a4-3) include structural units represented by the formulas (a4-1'-1) to (a4-1'-22).

The structural unit (a4) also includes a structural unit represented by the formula (a4-4).
[In equation (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 represent integers 1 to 6 independently of each other.
R ^f22 represents a hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

^Examples of the hydrocarbon group having a fluorine atom of R ^f22 include the same hydrocarbon group as R ^f2 in the formula (a4-2).
R ^f22 is preferably an alkyl group having 1 to 10 carbon atoms having a fluorine atom or an alicyclic hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom, and an alkyl having 1 to 10 carbon atoms having a fluorine atom. It is more preferably a group, and further preferably an alkyl group having 1 to 6 carbon atoms having a fluorine atom.

In the formula (a4-4), as A ^f21 , − (CH ₂ ) _j1 − is preferable, an ethylene group or a methylene group is more preferable, and a methylene group is further preferable.

Examples of the structural unit represented by the formula (a4-4) include the following structural units.

When the resin (A) has the structural unit (a4), the content thereof is preferably 1 to 20 mol%, preferably 2 to 15 mol%, based on the total of all the structural units of the resin (A). Is more preferable, and 3 to 10 mol% is further preferable.

<Structural unit (a5)>
Examples of the non-eliminating hydrocarbon group contained in the structural unit (a5) include a linear, branched or cyclic hydrocarbon group. Among them, the structural unit (a5) is preferably an alicyclic hydrocarbon group.
Examples of the structural unit (a5) include a structural unit represented by the formula (a5-1).
[In equation (a5-1),
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with an aliphatic hydrocarbon group or a hydroxy group having 1 to 8 carbon atoms. You may.
However, the hydrogen atom bonded to the carbon atom at the bond position with L ⁵⁵ is not replaced by an aliphatic hydrocarbon group having 1 to 8 carbon atoms.
L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. ]

The alicyclic hydrocarbon group of R ⁵² may be either a monocyclic or polycyclic group. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group and a norbornyl group.
The aliphatic hydrocarbon group having 1 to 8 carbon atoms includes, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. Alkyl groups such as an octyl group and a 2-ethylhexyl group can be mentioned.
Examples of the alicyclic hydrocarbon group having a substituent include a 3-hydroxyadamantyl group and a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.

Examples of the divalent saturated hydrocarbon group of L ⁵⁵ include a divalent aliphatic saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, preferably a divalent aliphatic saturated hydrocarbon group. Be done.
Examples of the divalent aliphatic saturated hydrocarbon group include an alkanediyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentandiyl group.
The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include a cycloalkanediyl group such as a cyclopentanediyl group and a cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantandiyl group and a norbornanediyl group.

Examples of the group in which the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group include groups represented by the formulas (L1-1) to (L1-4). In the following formula, * represents a bond with an oxygen atom.
[In equation (L1-1),
X ^x1 represents a carbonyloxy group or an oxycarbonyl group.
L ^x1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
L ^x2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
However, the total number of carbon atoms of L ^x1 and L ^x2 is 16 or less.
In formula (L1-2),
L ^x3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.
L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total number of carbon atoms of L ^x3 L ^x4 is 17 or less.
In formula (L1-3),
L ^x5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^x6 and L ^x7 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms independently of each other.
However, the total number of carbon atoms of L ^x5 , L ^x6 and L ^x7 is 15 or less.
In formula (L1-4),
L ^x8 and L ^x9 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
W ^x1 represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms.
However, the total number of carbon atoms of L ^x8 , L ^x9 and W ^x1 is 15 or less. ]

L ^x1 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond.
L ^x3 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.
L ^x6 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.
L ^x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond or a methylene group.
L ^x9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond or a methylene group.
W ^x1 is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, and more preferably a cyclohexanediyl group or an adamantandiyl group.

Examples of the group represented by the formula (L1-1) include the divalent groups shown below.

Examples of the group represented by the formula (L1-2) include the divalent groups shown below.

Examples of the group represented by the formula (L1-3) include the divalent groups shown below.

Examples of the group represented by the formula (L1-4) include the divalent groups shown below.

L ⁵¹ is preferably a single bond or a group represented by the formula (L1-1).

Examples of the structural unit (a5-1) include the following.

In the formulas (a5-1-19) to (a5-1-27), the structural unit in which the methyl group corresponding to R ⁵¹ is replaced with a hydrogen atom can also be mentioned as a specific example of the structural unit (a5-1). it can.

When the resin (A) has the structural unit (a5), the content thereof is preferably 1 to 30 mol%, preferably 2 to 20 mol%, based on the total of all the structural units of the resin (A). Is more preferable, and 3 to 15 mol% is further preferable.

The resin (A) is preferably a resin composed of a structural unit (a1) and a structural unit (s), that is, a copolymer of a monomer (a1) and a monomer (s).
The structural unit (a1) is preferably at least one selected from the structural unit (a1-1) and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group), and more preferably the structural unit (a1). At least two kinds selected from a1-1) and a structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group).
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 selected from the structural unit represented by the formula (a3-1), the structural unit represented by the formula (a3-2), and the structural unit represented by the formula (a3-4). At least one kind.

The resin (A) may contain a structural unit (particularly, a structural unit (a1-1)) derived from a monomer having an adamantane group in an amount of 15 mol% or more based on the content of the structural unit (a1). preferable. As the content of the structural unit having an adamantyl group increases, 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, a radical polymerization method) using a monomer for inducing these structural units. can do. The content of each structural unit of the resin (A) can be adjusted by adjusting the amount of the monomer used for the polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, still more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less, still more preferably. 15,000 or less).
In the present specification, the weight average molecular weight is a value determined by gel permeation chromatography. Gel permeation chromatography can be measured under the analytical conditions described in the Examples.

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). Examples of the resin other than the resin (A) include a resin composed of only the structural unit (s). Among them, a resin containing a structural unit (a4) (however, a resin containing no structural unit (a1); hereinafter may be referred to as “resin (X)”) is preferable.
In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, based on the total of all the structural units of the resin (X). , 50 mol% or more is more preferable.

Examples of the structural unit that the resin (X) may further include include a structural unit (a2), a structural unit (a3), and a structural unit derived from other known monomers.
The weight average molecular weight of the resin (X) is preferably 6,000 or more (more preferably 7,000 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 of the resin (A).
When the resist composition contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and further, with respect to 100 parts by mass of the resin (A). It is preferably 2 to 40 parts by mass, and particularly preferably 3 to 30 parts by mass.

The total content of the resin (A) and the resin other than the resin (A) is preferably 80% by mass or more and 99% by mass or less, more preferably 90 to 99% by mass, based on the solid content of the resist composition. The solid content of the resist composition and the content of the resin relative to the solid content can be measured by a known analytical means such as liquid chromatography or gas chromatography.

<Citron (C)>
The quencher (C) that may be contained in the resist composition of the present invention is a compound having an action of capturing acid generated from an acid generator by exposure.
Examples of the quencher (C) include a basic nitrogen-containing organic compound or a salt (a) and a salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B).
Examples of the basic nitrogen-containing organic compound include amine and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Examples of aliphatic amines include primary amines, secondary amines and tertiary amines.

Examples of amines 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, trypentylamine, trihexylamine, tri Heptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, Ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, tri Isopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3 , 3'-diethyldiphenylmethane, piperazin, morpholin, piperidine and hindered amine compounds having a piperidine skeleton described in JP-A-11-52575, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 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'-Dipicolylamine, bipyridine and the like, preferably diisopropylaniline, and particularly preferably 2,6-diisopropylaniline.

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

Examples of the salt that generates an acid having a weaker acidity than the acid generated from the salt (I) and the acid generator (B) include a salt represented by the following formula, a weak acid intramolecular salt represented by the formula (D), and the like. Examples thereof include the salts described in JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011-39502 and JP-A-2011-191745. It is preferably a weak acid intramolecular salt represented by the formula (D) (hereinafter, may be referred to as “weak acid intramolecular salt (D)”).
The acidity of a salt that produces an acid that is weaker than the acid generated from the salt (I) and the acid generator (B) is indicated by the acid dissociation constant (pKa). A salt that generates an acid having a weaker acidity than the acid generated from the salt (I) and the acid generator (B) is a salt having an acid dissociation constant of the acid generated from the salt usually -3 <pKa. A salt of -1 <pKa <7 is preferable, and a salt of 0 <pKa <5 is more preferable.

[In formula (D),
R ^D1 and R ^D2 are independent of each other, a monovalent hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, and an acyloxy group having 2 to 7 carbon atoms. Represents an alkoxycarbonyl group, a nitro group or a halogen atom having 2 to 7 carbon atoms.
m'and n'independently represent integers 0 to 4, and when m'is 2 or more, a plurality of R ^D1s may be the same or different, and when n'is 2 or more, The plurality of R ^D2s may be the same or different. ]

In the weak acid intramolecular salt (D), the hydrocarbon groups of ^RD1 and ^RD2 include monovalent aliphatic hydrocarbon groups, monovalent alicyclic hydrocarbon groups, and monovalent aromatic hydrocarbon groups. Examples thereof include groups formed by combining these.
Examples of the monovalent aliphatic hydrocarbon group include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group and nonyl group.
The monovalent alicyclic hydrocarbon group may be either monocyclic or polycyclic, and may be saturated or unsaturated. Examples thereof include cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclononyl group and cyclododecyl group, norbonyl group and adamantyl group.
Examples of the monovalent aromatic hydrocarbon group include phenyl group, 1-naphthyl group, 2-naphthyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group and 4-. Propylphenyl group, 4-isopropylphenyl group, 4-butylphenyl group, 4-tert-butylphenyl group, 4-hexylphenyl group, 4-cyclohexylphenyl group, anthryl group, p-adamantylphenyl group, trill group, xsilyl group , Cumenyl group, mesityl group, biphenyl group, phenanthryl group, aryl group such as 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl and the like.
Examples of the group formed by combining these groups include an alkyl-cycloalkyl group, a cycloalkyl-alkyl group, and an aralkyl group (for example, phenylmethyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenyl-). 1-propyl group, 1-phenyl-2-propyl group, 2-phenyl-2-propyl group, 3-phenyl-1-propyl group, 4-phenyl-1-butyl group, 5-phenyl-1-pentyl group, 6-Phenyl-1-hexyl group, etc.) and the like.

Examples of the alkoxy group include a methoxy group and an ethoxy group.
Examples of the acyl group include an acetyl group, a propanoyl group, a benzoyl group, a cyclohexanecarbonyl group and the like.
Examples of the acyloxy group include a group in which an oxy group (−O−) is bonded to the above acyl group.
Examples of the alkoxycarbonyl group include a group in which a carbonyl group (−CO−) is bonded to the above alkoxy group.
Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.

In the formula (D), R ^D1 and R ^D2 are independent of each other, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and 2 to 2 carbon atoms. It is preferably an acyl group of 4, an acyloxy group having 2 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a nitro group or a halogen atom.
m'and n'are preferably integers of 0 to 2 independently of each other, and more preferably 0. When m'is 2 or more, the plurality of R ^D1s may be the same or different, and when n'is 2 or more, the plurality of R ^D2s may be the same or different.

Examples of the weak acid intramolecular salt (D) include the following compounds.

The weak acid intramolecular salt (D) can be produced by the method described in "Tetrahedron Vol. 45, No. 19, p6281-6296". Further, as the weak acid intramolecular salt (D), a commercially available compound can be used.

The content of the quencher (C) is preferably 0.01 to 5% by mass, more preferably 0.01 to 4% by mass, and particularly preferably 0.01 to 3% by mass, based on the solid content of the resist composition. It is mass%.

<Solvent (E)>
The content of the solvent (E) is usually 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more, and usually 99.9% by mass or less, preferably 99% by mass or less in the resist composition. Is. The content of the solvent (E) can be measured by a known analytical means such as liquid chromatography or gas chromatography.

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 ethyl pyruvate. Esters; ketones such as acetone, methylisobutylketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; and the like. The solvent (E) may contain one type alone or two or more types.

<Other ingredients>
If necessary, the resist composition may contain components other than the above-mentioned components (hereinafter, may be referred to as "other components (F)"). As the other component (F), additives known in the field of resist, for example, sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes and the like can be used.

<Preparation of resist composition>
The resist composition includes a resin (A) and a salt (I), and if necessary, a resin other than the resin (A), an acid generator (B), a solvent (E), a quencher (C), and other substances. It can be prepared by mixing the component (F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can be selected from 10 to 40 ° C., depending on the type of resin or the like and the solubility of the resin or the like in the solvent (E). As the mixing time, an appropriate 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 or the like 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.

<Manufacturing method of resist pattern>
The method for producing a resist pattern of the present invention is
(1) A step of applying the resist composition of the present invention on a substrate,
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
It includes (4) a step of heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

The resist composition can be applied onto the substrate by a commonly used device such as a spin coater. Examples of the substrate include an inorganic substrate such as a silicon wafer. Before applying the resist composition, the substrate may be washed, or an antireflection film or the like may be formed on the substrate.

By drying the applied composition, the solvent is removed and a composition layer is formed. Drying is carried out, for example, by evaporating the solvent using a heating device such as a hot plate (so-called prebaking), or by using a decompression device. The heating temperature is preferably 50 to 200 ° C., and the heating time is preferably 10 to 180 seconds. The pressure at the time of vacuum drying is preferably about 1~1.0 × ¹⁰ 5 Pa.

The obtained composition layer is usually exposed to an exposure machine. The exposure machine may be an immersion exposure machine. The exposure light source, which emits laser light in a UV-region such as a KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), _{F 2} excimer laser (wavelength 157 nm), solid-state laser source (YAG or semiconductor laser Etc.), wavelength-converted laser light from far-ultraviolet region or vacuum ultraviolet region to emit harmonic laser light, electron beam, super-ultraviolet light (EUV) irradiation, etc. Can be done. In addition, in this specification, irradiation of these radiations may be generically referred to as "exposure". At the time of exposure, the exposure is usually performed through a mask corresponding to the required pattern. When the exposure light source is an electron beam, the exposure may be performed by drawing directly without using a mask.

The composition layer after exposure is heat-treated (so-called post-exposure baking) to promote the deprotection reaction at the acid unstable group. The heating temperature is usually about 50 to 200 ° C, preferably about 70 to 150 ° C.

The composition layer after heating is usually developed using a developing solution using a developing device. Examples of the developing method include a dip method, a paddle method, a spray method, and a dynamic dispense method. The developing temperature is preferably 5 to 60 ° C., and the developing time is preferably 5 to 300 seconds. A positive resist pattern or a negative resist pattern can be produced by selecting the type of developer as follows.

When a positive resist pattern is produced from a resist composition, an alkaline developer is used as the developer. The alkaline developer may be any alkaline aqueous solution used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline). The alkaline developer may contain a surfactant.
After development, it is preferable to wash the resist pattern with ultrapure water and then remove the substrate and water remaining on the pattern.

When a negative resist pattern is produced from a resist composition, a developer containing an organic solvent (hereinafter, may be referred to as "organic developer") is used as the developer.
Examples of the organic solvent contained in the organic developing solution 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; propylene glycol monomethyl ether. Glycol ether solvents such as, amide solvents such as N, N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole, and the like.
The content of the organic solvent in the organic developer 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 is substantially only the organic solvent. Is even more preferable.
As the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. When the organic developer contains butyl acetate and 2-heptanone, the total content thereof is preferably 50% by mass or more and 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less. Preferably, it is substantially only butyl acetate and / or 2-heptanone.
The organic developer may contain a surfactant. Further, the organic developer may contain a small amount of water.
At the time of development, the development may be stopped by substituting with a solvent of a type different from that of the organic developer.

It is preferable to wash the developed resist pattern with a rinse solution. The rinsing solution 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 can be preferably used.
After cleaning, it is preferable to remove the rinse liquid remaining on the substrate and the pattern.

<Use>
The resist composition of the present invention includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, particularly ArF. It is suitable as a resist composition for excimer laser exposure and is useful for fine processing of semiconductors.

A more specific description will be given with reference to examples. In the examples, "%" and "part" representing the content or the amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value obtained by gel permeation chromatography under the following conditions.
Equipment: HLC-8120GPC type (manufactured by Tosoh)
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh)
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)

The structure of the compound was confirmed by measuring the molecular peak using mass analysis (LC: Agilent 1100 type, MASS: Agilent LC / MSD type). In the following examples, the value of this molecular peak is indicated by "MASS".

Example 1: Synthesis of salt represented by formula (I-1)
4.76 parts of the salt represented by the formula (I-1-a), 0.80 parts of the compound represented by the formula (I-1-b) and 40 parts of chloroform were added, and the mixture was stirred at 23 ° C. for 30 minutes. .. 0.02 part of the compound represented by the formula (I-1-c) was added to the obtained mixed solution, and the mixture was further stirred at 60 ° C. for 72 hours under the formula (I-1-d). A reaction mixture containing the salt represented was obtained.

In the reaction mixture containing the salt represented by the formula (I-1-d), 4.76 parts of the salt represented by the formula (I-1-a) and the compound represented by the formula (I-1-c) are added. 0.02 part was added, and the mixture was further refluxed and stirred at 60 ° C. for 72 hours. The obtained reaction mass was cooled to 23 ° C., 15 parts of a 5% oxalic acid aqueous solution was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated to remove the organic layer. This operation was repeated 5 times. The obtained organic layer was filtered, the recovered filtrate was concentrated, 3 parts of acetonitrile and 80 parts of tert-butyl methyl ether were added to the obtained residue, and the mixture was stirred for 30 minutes and filtered. 3.48 parts of salt represented by I-1-e) was obtained.

2.20 parts of the salt represented by the formula (I-1-e) and 20 parts of 1,2-dichloroethane were charged and stirred at 23 ° C. for 30 minutes. Then, 2.77 parts of the compound represented by the formula (I-1-f) and 0.15 parts of p-toluenesulfonic acid were added, and the mixture was refluxed and stirred at 100 ° C. for 3 hours. The obtained reaction product was cooled to 23 ° C., 60 parts of chloroform and 17.7 parts of an 8.7% aqueous sodium hydrogen carbonate solution were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it was allowed to stand and the liquid was separated. 30 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed 5 times. 0.50 part of activated carbon was charged into the obtained organic layer, stirred at 23 ° C. for 30 minutes, and filtered. By concentrating the filtrate, 2.21 parts of a salt represented by the formula (I-1) was obtained.

MS (ESI (+) Spectrum): M ⁺ 386.2
MS (ESI (-) Spectrum): M ^- 467.1

Example 2: Synthesis of salt represented by formula (I-2)
4.87 parts of the salt represented by the formula (I-2-a), 0.80 part of the compound represented by the formula (I-2-b) and 40 parts of chloroform were added, and the mixture was stirred at 23 ° C. for 30 minutes. .. 0.02 part of the compound represented by the formula (I-2-c) was added to the obtained mixed solution, and the mixture was further stirred at 60 ° C. for 72 hours under the formula (I-2-d). A reaction mixture containing the salt represented was obtained.

In the reaction mixture containing the salt represented by the formula (I-2-d), 4.76 parts of the salt represented by the formula (I-2-e) and the compound represented by the formula (I-2-c). 0.02 part was added, and the mixture was further refluxed and stirred at 60 ° C. for 72 hours. The obtained reaction mass was cooled to 23 ° C., 15 parts of a 5% oxalic acid aqueous solution was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes to separate the liquids, and the organic layer was taken out.
This operation was repeated 5 times. The obtained organic layer was filtered, the recovered filtrate was concentrated, 3 parts of acetonitrile and 80 parts of tert-butyl methyl ether were added to the obtained residue, and the mixture was stirred for 30 minutes and filtered. 3.16 parts of salt represented by I-2-f) was obtained.

2.24 parts of the salt represented by the formula (I-2-f) and 20 parts of 1,2-dichloroethane were charged and stirred at 23 ° C. for 30 minutes. Then, 1.39 parts of the compound represented by the formula (I-2-g) and 0.08 parts of p-toluenesulfonic acid were added, and the mixture was stirred at 100 ° C. for 1 hour. The obtained reaction product was cooled to 23 ° C., 30 parts of chloroform and 8.9 parts of an 8.7% aqueous sodium hydrogen carbonate solution were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it was allowed to stand and the liquid was separated. 30 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed 5 times. 0.50 part of activated carbon was charged into the obtained organic layer, stirred at 23 ° C. for 30 minutes, and filtered. The recovered filtrate was concentrated, and 10 parts of acetonitrile was added to the obtained residue, and the mixture was stirred and concentrated. To the obtained residue, 20 parts of tert-butyl methyl ether was added, and the mixture was stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated to obtain 1.98 parts of a salt represented by the formula (I-2). Got

MS (ESI (+) Spectrum): M ⁺ 386.2
MS (ESI (-) Spectrum): M ^- 467.1
MS (ESI (-) Spectrum): M ^- 339.1

Example 3: Synthesis of salt represented by formula (I-3)
50 parts of the compound represented by the formula (I-3-a), 11.92 parts of the compound represented by the formula (I-3-b) and 350 parts of chloroform were charged, stirred at 23 ° C. for 30 minutes, and then acetic acid. 0.20 part of copper (II) was charged, refluxed at 80 ° C. for 2 hours, and then concentrated. 440 parts of tert-butyl methyl ether was added to the recovered concentrate, stirred, and then filtered to obtain 33.08 parts of a salt represented by the formula (I-3-c).

After charging 3.82 parts of the salt represented by the formula (I-3-c) and 60 parts of chloroform, 9.21 parts of the salt represented by the formula (I-3-d) and 30 parts of ion-exchanged water were added. The mixture was charged and stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 30 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. The obtained organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the obtained residue and stirred to remove the supernatant. By concentrating the obtained residue, 4.28 parts of a salt represented by the formula (I-3-e) was obtained.

After charging 5.29 parts of the salt represented by the formula (I-3-a) and 60 parts of chloroform, 9.21 parts of the salt represented by the formula (I-3-d) and 30 parts of ion-exchanged water were added. The mixture was charged and stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 30 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. The obtained organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the obtained residue and stirred to remove the supernatant. By concentrating the obtained residue, 8.14 parts of a salt represented by the formula (I-3-f) was obtained.

3.92 parts of salt represented by formula (I-3-e), 4.85 parts of salt represented by formula (I-3-f) and compound 0 represented by formula (I-1-c). .02 parts were added, and the mixture was further refluxed and stirred at 60 ° C. for 72 hours. The obtained reaction mass was cooled to 23 ° C., 15 parts of a 5% oxalic acid aqueous solution was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated to remove the organic layer. This operation was repeated 5 times. The obtained organic layer was filtered, the recovered filtrate was concentrated, 3 parts of acetonitrile and 50 parts of tert-butyl methyl ether were added to the obtained residue, and the mixture was stirred for 30 minutes and filtered. 5.65 parts of salt represented by I-3-g) was obtained.

2.26 parts of the salt represented by the formula (I-3-g) and 20 parts of 1,2-dichloroethane were charged and stirred at 23 ° C. for 30 minutes. Then, 2.77 parts of the compound represented by the formula (I-1-f) and 0.15 parts of p-toluenesulfonic acid were added, and the mixture was refluxed and stirred at 100 ° C. for 3 hours. The obtained reaction product was cooled to 23 ° C., 60 parts of chloroform and 17.7 parts of an 8.7% aqueous sodium hydrogen carbonate solution were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it was allowed to stand and the liquid was separated. 30 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed 5 times. 0.50 part of activated carbon was charged into the obtained organic layer, stirred at 23 ° C. for 30 minutes, and filtered. By concentrating the filtrate, 2.21 parts of a salt represented by the formula (I-1) was obtained.

MS (ESI (+) Spectrum): M ⁺ 386.2
MS (ESI (-) Spectrum): M ^- 481.1

Synthesis example 1: Synthesis of salt represented by the formula (B1-5)

50.49 parts of salt represented by the formula (B1-5-a) and 252.44 parts of chloroform were charged into the reactor, stirred at 23 ° C. for 30 minutes, and the compound represented by the formula (B1-5-b). 16.27 parts were added dropwise, and the mixture was stirred at 23 ° C. for 1 hour to obtain a solution containing a salt represented by the formula (B1-5-c). To the obtained solution containing the salt represented by the formula (B1-5-c), 48.80 parts of the salt represented by the formula (B1-5-d) and 84.15 parts of ion-exchanged water were added. The mixture was stirred at 23 ° C. for 12 hours. Since the obtained reaction solution was separated into two layers, the chloroform layer was separated and taken out, and 84.15 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. 3.88 parts of activated carbon was added to the obtained chloroform layer, stirred, and filtered. The recovered filtrate was concentrated, and 125.87 parts of acetonitrile was added to the obtained residue, and the mixture was stirred and concentrated. To the obtained residue, 20.62 parts of acetonitrile and 309.30 parts of tert-butyl methyl ether were added, and the mixture was stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated. To the obtained residue, 200 parts of n-heptane was added, stirred at 23 ° C. for 30 minutes, and filtered to obtain 61.54 parts of a salt represented by the formula (B1-5).
MASS (ESI (+) Spectrum): M ⁺ 375.2
MASS (ESI (-) Spectrum): M ^- 339.1

Synthesis Example 2 [Synthesis of salt represented by formula (B1-21)]
30.00 parts of the compound represented by the formula (B1-21-b) obtained by the method described in JP-A-2008-209917, and the salt 35.50 represented by the formula (B1-21-a). 100 parts of chloroform and 50 parts of ion-exchanged water were charged and stirred at 23 ° C. for 15 hours.
Since the obtained reaction solution was separated into two layers, the chloroform layer was separated and taken out, and 30 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer is concentrated, 100 parts of tert-butyl methyl ether is added to the obtained residue, the mixture is stirred at 23 ° C. for 30 minutes, and then filtered to obtain a salt 48 represented by the formula (B1-21-c). Obtained .57 copies.

20.00 parts of the salt represented by the formula (B1-21-c), 2.84 parts of the compound represented by the formula (B1-21-d) and 250 parts of monochlorobenzene were charged and stirred at 23 ° C. for 30 minutes. ..
After adding 0.21 part of copper (II) dibenzoate to the obtained mixed solution, the mixture was further stirred at 100 ° C. for 1 hour. The obtained reaction solution was concentrated. To the obtained residue, 200 parts of chloroform and 50 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. 50 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated to remove the organic layer. This washing operation was repeated 5 times. The obtained organic layer was concentrated, and the obtained residue was dissolved in 53.51 parts of acetonitrile and concentrated. Then, 113.05 parts of tert-butyl methyl ether was added, stirred, and filtered to obtain 10.47 parts of the salt represented by the formula (B1-21).

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 339.1

Synthesis Example 3 [Synthesis of salt represented by formula (B1-22)]
11.26 parts of salt represented by the formula (B1-22-a), 10.00 parts of the compound represented by the formula (B1-22-b), 50 parts of chloroform and 25 parts of ion-exchanged water were charged and 23 ° C. Was stirred for 15 hours. Since the obtained reaction solution was separated into two layers, the chloroform layer was separated and taken out, and 15 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer is concentrated, 50 parts of tert-butyl methyl ether is added to the obtained residue, the mixture is stirred at 23 ° C. for 30 minutes, and filtered to obtain a salt represented by the formula (B1-22-c). We got 75 copies.

11.71 parts of the salt represented by the formula (B1-22-c), 1.70 parts of the compound represented by the formula (B1-22-d) and 46.84 parts of monochlorobenzene were charged and charged at 23 ° C. for 30 minutes. Stirred. To the obtained mixed solution, 0.12 part of copper (II) dibenzoate was added, and the mixture was further stirred at 100 ° C. for 30 minutes. The obtained reaction solution was concentrated. To the obtained residue, 50 parts of chloroform and 12.50 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. 12.50 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. This washing operation was repeated 8 times. The obtained organic layer was concentrated, and 50 parts of tert-butyl methyl ether was added to the obtained residue and stirred. Then, by filtration, 6.84 parts of a salt represented by the formula (B1-22) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 323.0

Synthesis of Resin The compounds (monomers) used for the synthesis of the resin (A) are shown below. Hereinafter, these compounds are referred to as "monomers (a1-1-3)" and the like according to their formula numbers.

Synthesis Example 4: Synthesis of Resin A1 As a monomer, a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3) and a monomer (a3-4-2) are used. The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-4-2)] is 45: 14: 2.5: 38. The mixture was mixed so as to have a concentration of 5, and propylene glycol monomethyl ether acetate 1.5% by mass of the total amount of the monomers was added to prepare a solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 1 mol% and 3 mol%, respectively, based on the total amount of monomers, 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 a resin, and the resin was filtered. The obtained resin is dissolved again in propylene glycol monomethyl ether acetate, and the obtained solution is poured into a methanol / water mixed solvent to precipitate the resin, and the resin is filtered. A resin A1 having a molecular weight of 7.6 × 10 ³ was obtained in a yield of 68%. This resin A1 has the following structural units.

Synthesis Example 5: Synthesis of resin X1 A monomer (a4-1-7) was used as a monomer, and methyl isobutyl ketone 1.5% by mass of the total amount of the monomer was added to prepare a solution. To this solution, 0.7 mol% and 2.1 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total amount of the monomers, respectively, and these were added at 75 ° C. It was heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and the resin was filtered. The obtained resin was dissolved in dioxane again, and the obtained solution was poured into a methanol / water mixed solvent to precipitate the resin, and the reprecipitation operation of filtering the resin was performed twice, and the weight average molecular weight was 1.7. The resin X1 of × 10 ⁴ was obtained in a yield of 77%. This resin X1 has the following structural units.

Synthesis Example 6: Synthesis of resin X2 A monomer (a4-0-12) was used as a monomer, and methyl isobutyl ketone 1.5% by mass of the total amount of the monomer was added to prepare a solution. To this solution, 0.7 mol% and 2.1 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total amount of the monomers, respectively, and these were added at 75 ° C. It was heated for about 5 hours.
The reaction mixture obtained, the resin was precipitated by pouring into a large amount of methanol / water mixed solvent, the resin was filtered, to obtain a resin X2 of the weight average molecular weight 1.5 × 10 ⁴ in 77% yield. This resin X2 has the following structural units.

Synthesis Example 7: Synthesis of resin X3 A monomer (a5-1-1) and a monomer (a4-0-12) are used as monomers, and the molar ratio thereof [monomer (a5-1-1): monomer (a4-0-). 12)] was mixed so that the ratio was 50:50, and methyl isobutyl ketone, which was 1.2% by mass of the total amount of monomers, was added to prepare a solution. Azobis (2,4-dimethylvaleronitrile) as an initiator was added to this solution in an amount of 3 mol% based on the total amount of monomers, and the solution was heated at 70 ° C. for about 5 hours. The reaction mixture obtained, the resin was precipitated by pouring into a large amount of methanol / water mixed solvent, the resin was filtered, to obtain a resin X3 of weight average molecular weight 1.0 × 10 ⁴ in 91% yield. This resin X3 has the following structural units.

<Preparation of resist composition>
As shown in Table 1, each of the following components was mixed, and the obtained mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1, X1 to X3: Resin A1, Resin X1 to Resin X3
<Acid generator>
I-1: Salt represented by formula (I-1) I-2: Salt represented by formula (I-2) I-3: Salt represented by formula (I-3) B1-5: Formula Salt represented by (B1-5) B1-21: Salt represented by formula (B1-21) B1-22: Salt represented by formula (B1-22) B1-X1: JP-A-2003-342254 Synthesized according to the examples in the publication
B1-X2: Synthesized according to the examples of JP2012-97074A.
<Compound (D)>
D1: (manufactured by Tokyo Kasei Kogyo Co., Ltd.)
<Solvent>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-Heptanone 20 parts γ-butyrolactone 3.5 parts

<Manufacturing of resist pattern and its evaluation>
An organic antireflection film composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] is applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain an organic thickness of 78 nm. 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 (prebaking) was 85 nm. The silicon wafer coated with the resist composition was prebaked on a direct hot plate at the temperature listed in the “PB” column of Table 1 for 60 seconds to form a composition layer on the silicon wafer.
ArF excimer laser stepper for immersion exposure [XT: 1900Gi; manufactured by ASML, NA = 1.35, Dipole 0.900 / 0.700 Y-pol. On a composition layer formed on a silicon wafer. In [Illumination], a mask for forming a trench pattern (pitch 120 nm / trench 40 nm) was used, and the exposure amount was changed stepwise for exposure. Ultrapure water was used as the immersion medium. After the exposure, post-exposure baking was performed on a hot plate at the temperature listed in the “PEB” column of Table 1 for 60 seconds. Next, the heated composition layer was developed by the dynamic dispense method at 23 ° C. for 20 seconds using butyl acetate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a developing solution to produce a negative resist pattern. ..

In the obtained resist pattern, the exposure amount at which the line width of the trench pattern was 40 nm was defined as the effective sensitivity.

<Focus margin evaluation (DOF)>
In terms of effective sensitivity, a negative resist pattern was manufactured by performing the same operation as above except that the focus was changed stepwise for exposure. In the obtained resist pattern, the focus range in which the width of the trench pattern was 40 nm ± 5% (38 to 42 nm) was defined as DOF (nm). The results are shown in Table 2.

From the above results, it can be seen that the resist composition of the present invention can form a pattern having a good focus margin.

The salt, acid generator, and resist composition of the present invention can form a pattern having a good focus margin and are useful for microfabrication of semiconductors.

Claims (9)

Salt having a cation represented by represented by at least one formula (IA) Rua anion of the formula (IC).
[In formula (IA) ,
X ^a and X ^b represent an oxygen atom or a sulfur atom independently of each other.
X ¹ _{is, * -CH 2 -CF 2 -CH 2} - *, * - CH 2 - (CF 2) 2 -CH 2 - *, * - CH 2 - (CF 2) 3 -CH 2 - *, * _{-CH 2 - (CF 2) 4} -CH 2 - *, * - CH 2 - (CF 2) 5 -CH 2 - * or _* -CH 2 _- represents a _{* - (CF 2) 6 -CH} 2. * Represents a bond with X ^a and X ^b , respectively .
The ring W represents a ring represented by the formula (Iaa-1), a ring represented by the formula (Iaa-2), or a ring represented by the formula (Iaa-3).
L ^b1 represents a group represented by any of the following. * Represents a bond with the ring W.
Q ¹ and ^{Q 2} independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. ]
[In the formula (IC),
R ¹ and R ² independently represent a hydrogen atom, a hydroxy group, or a hydrocarbon group having 1 to 12 carbon atoms, and −CH ₂ − contained in the hydrocarbon group is −O− or −CO−. It may be replaced.
m and n represent 1 or 2 independently of each other. when m is 2, two R ¹ may be the same or different, when n is 2, the two R ² may be the same or different.
Ar ¹ and Ar ² are independently of each other, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic aromatic group having 6 to 36 carbon atoms which may have a substituent. Represents a hydrocarbon group. ] Salt according to claim 1, further comprising two represented luer anions by the formula (IA). L ^b1 is, * - CO-O - or _* -CH 2 -O-CO- _(* ^{is, -C (Q 1) (Q} 2) -. Representing a bond to) a is claim 1 or 2. The salt described. An acid generator containing the salt according to any one of claims 1 to 3 as an active ingredient. A resist composition containing the acid generator according to claim 4 and a resin containing a structural unit having an acid unstable group. The resist composition according to claim 5 , further comprising an acid generator represented by the formula (B1).
[In equation (B1),
Q ^{1, Q 2,} independently of each other, represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the saturated hydrocarbon may be replaced. The hydrogen atom contained in the hydrogen group may be substituted with a fluorine atom or a hydroxy group.
Y represents a methyl group which may have a substituent or a monovalent alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and the monovalent alicyclic hydrocarbon. -CH _2- contained in the hydrogen group may be replaced with -O-, -SO _2- or -CO-.
Z ⁺ represents an organic cation. However, Z ⁺ does not include the cation represented by the formula (IC). ] The resist composition according to claim 5 or 6 , further comprising a resin containing a structural unit having a fluorine atom. The resist composition according to any one of claims 5 to 7 , further comprising a salt that generates an acid having a weaker acidity than the acid generated from the acid generator. (1) A step of applying the resist composition according to any one of claims 5 to 8 onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
A method for producing a resist pattern, which comprises a step of (4) heating the composition layer after exposure and (5) a step of developing the composition layer after heating.