JP6769783B2 - Method for Producing Salt, Acid Generator, Resist Composition and Resist Pattern - Google Patents

Description

The present invention relates to a method for producing a salt, an acid generator, a resist composition and a resist pattern.

Patent Document 1 describes a resist composition containing a salt represented by the following formula as 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. 2013-33161 Japanese Unexamined Patent Publication No. 2012-224611

The resist pattern formed from the above resist composition may not always be satisfactory in terms of focus margin (DOF).

The present invention includes the following inventions.
[1] A salt represented by the formula (I).
[In formula (I),
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 independently represent 1 or 2, respectively. When m is 2, the two R ^1s are the same or different, and when n is 2, the two R ^2s are the same or different.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic hydrocarbon group having 5 to 36 carbon atoms which may have a substituent.
A ¹ represents an (1 + s) -valent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms which may have a hydroxy group, and −CH ₂ − contained in the aliphatic saturated hydrocarbon group is −O. -Or-CO- may be replaced.
R ³ represents an alicyclic hydrocarbon group having 5 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group, or the alicyclic hydrocarbon group may be substituted. The two hydrogen atoms contained in the above may be replaced with oxygen atoms, respectively, and the two oxygen atoms may be combined with an alcandiyl group having 1 to 8 carbon atoms to form a ketal ring, and the ketal ring may form a fluorine atom. It may have, and the -CH _2- group contained in the alicyclic hydrocarbon group may be replaced with -O- or -CO-.
s represents an integer of 1-3. ]
[2] R ³ is an adamantyl group, and the hydrogen atom contained in the adamantyl group may be substituted with a hydroxy group, or two hydrogen atoms contained in the adamantyl group are each substituted with an oxygen atom, and the 2 One oxygen atom may be combined with an alkandiyl group having 1 to 8 carbon atoms to form a ketal ring which may contain a fluorine atom, and the methylene group contained in the adamantyl group is replaced with an oxygen atom or a carbonyl group. The salt according to [1] which may be present.
[3] The salt according to [1] or [2], wherein Ar is a phenyl group which may have a substituent.
[4] The salt according to any one of [1] to [3], wherein A ¹ is a (1 + s) -valent aliphatic saturated hydrocarbon group having 2 to 5 carbon atoms.
[5] An acid generator containing the salt according to any one of [1] to [4].
[6] A resist composition containing the acid generator according to [5] and a resin containing a structural unit having an acid unstable group.
[7] The resist composition according to [6], which contains a salt having a weaker acidity than the acid generated from the acid generator.
[8] The resist composition according to [6] or [7], which further contains a resin containing a structural unit having a fluorine atom.
[9] (1) A step of applying the resist composition according to any one of [6] 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 (4) a step of heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

According to the resist composition of the present invention, a resist pattern having a good focus margin (DOF) can be produced.

As used herein, the term "(meth) acrylate" means "at least one of acrylate and methacrylate," respectively. Notations such as "(meth) acrylic acid" and "(meth) acryloyl" have the same meaning.
Unless otherwise specified, groups that can be linear, branched, or cyclic, such as "aliphatic hydrocarbon groups," include any of them. If stereoisomers are present, they include all stereoisomers.
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 is a salt represented by the formula (I) (hereinafter, may be referred to as "salt (I)").
[In formula (I),
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 independently represent 1 or 2, respectively. When m is 2, the two R ^1s are the same or different, and when n is 2, the two R ^2s are the same or different.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic hydrocarbon group having 5 to 36 carbon atoms which may have a substituent.
A ¹ represents an (1 + s) -valent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms which may have a hydroxy group, and −CH ₂ − contained in the aliphatic saturated hydrocarbon group is −O. It may be replaced by − or −CO−.
R ³ represents an alicyclic hydrocarbon group having 5 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group, or the alicyclic hydrocarbon group may be substituted. The two hydrogen atoms contained in the above may be replaced with oxygen atoms, respectively, and the two oxygen atoms may be combined with an alcandiyl group having 1 to 8 carbon atoms to form a ketal ring, and the ketal ring may form a fluorine atom. It may have, and the -CH _2- group contained in the alicyclic hydrocarbon group may be replaced with -O- or -CO-.
s represents an integer of 1-3. ]

In the following description, the side of the salt (I) having a negative charge may be referred to as "anion (I)", and the side having a positive charge may be referred to as "cation (I)".

Examples of the hydrocarbon groups 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.
Alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group and octyl group. , Nonyl group, decyl group, undecyl group, 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 groups such as dimethylcyclohexyl group, cycloheptyl group, cyclooctyl 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 combining these include an aralkyl group (benzyl group, phenethyl group, etc.), an alkyl-aryl group, a cyclohexyl-aryl group, an aryl-cyclohexyl 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.

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 source.
R ² is preferably a hydrogen atom.
It is preferable that at least one of R ¹ and R ² is a hydrogen atom, and it is more preferable that both are hydrogen atoms.

Examples of the aromatic hydrocarbon group of Ar include aryl groups having 6 to 36 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthonyl group, biphenyl group, triphenyl group, indenyl group, tetrahydronaphthyl group and phenanthryl group. Be done.
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 preferably has 6 to 24 carbon atoms, and more preferably 6 to 18 carbon atoms.
The heteroaromatic hydrocarbon group preferably has 5 to 24 carbon atoms, and more preferably 5 to 18 carbon atoms.

Examples of the substituent that Ar may have include a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and 2 carbon atoms. Examples thereof include an alkylcarbonyloxy group having ~ 18 and an arylcarbonyloxy group having 7 to 18 carbon atoms or an alkoxycarbonyloxy group having 2 to 18 carbon atoms, and −CH ₂ − contained in the alkoxy group having 1 to 18 carbon atoms is It may be replaced by −O−. It is preferably a hydroxy group.
Examples of the alkyl group 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 n-heptyl group. , 2-Ethylhexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group and the like. Among them, an alkyl group having 1 to 6 carbon atoms is preferable and methyl. A group, an ethyl group, an n-propyl group, an isopropyl group and a tert-butyl group are more preferable, a methyl group, an ethyl group, an isopropyl group and a tert-butyl group are further preferable, and a methyl group and a tert-butyl group are particularly preferable.
Examples of the alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group and the like, preferably an aliphatic hydrocarbon group having 3 to 10 carbon atoms, and more preferably an adamantyl group. Is.
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, and preferably have 1 to 1 carbon atoms. It is an alkoxy group of 6, 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 a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group, 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, 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, preferably an alkyloxycarbonyloxy group having 2 to 8 carbon atoms, more preferably. It is a tert-butyloxycarbonyloxy group.
Ar is preferably a phenyl group which may have a substituent or a naphthyl group which may have a substituent. As the substituents contained in Ar, an alkyl group having 1 to 12 carbon atoms, a hydroxy group, and an alkoxy group having 1 to 18 carbon atoms (however, -CH ₂ − contained in the alkoxy group having 1 to 18 carbon atoms is -O. It is preferable to replace with −), and the alkyl group having 1 to 12 carbon atoms and the alkoxy group having 1 to 18 carbon atoms (however, −CH ₂ − contained in the alkoxy group having 1 to 18 carbon atoms is − It is more preferable that it is replaced with O−), and the alkyl group having 1 to 12 carbon atoms and the alkoxy group having 1 to 14 carbon atoms (however, −CH ₂ − contained in the alkoxy group having 1 to 14 carbon atoms) is , -O- may be replaced.), And an alkyl group having 1 to 12 carbon atoms is even more preferable.

Examples of the cation of the salt (I) include cations represented by the following formulas (I-c-1) to (I-c-22).

Among them, the formula (I-c-1), the formula (I-c-3), the formula (I-c-4), the formula (I-c-7), the formula (I-c-12), the formula ( The cations represented by Ic-14), formula (Ic-16), formula (Ic-21) and formula (Ic-22) are preferred.

The (1 + s) -valent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms represented by A ¹ is a group obtained by removing s hydrogen atoms from the alkyl group or formulas (KA-1) to formulas (KA-19). ), Or a group having (1 + s) valence from which hydrogen atoms have been removed by combining two or more of the above alkyl groups and cycloalkane can be mentioned. .. The s or (1 + s) hydrogen atoms may be removed from one carbon atom constituting the aliphatic saturated hydrocarbon group, or may be removed from two or more carbon atoms. The hydrogen atom contained in the (1 + s) -valent aliphatic saturated hydrocarbon group may be replaced with a hydroxy group.

The removal of the hydrogen atoms by combining the alkyl group and the cycloalkane (1 + s) valent group, for example, the formula ^(X 1 -A), any of the formula ^(X 1 -B) and formula ^(X 1 -C) The group represented by can be mentioned.
[In the formula ^(X 1 -A) ~ Formula ^(X 1 -C) in,
X ^1A represents an alkanediyl group having 1 to 6 carbon atoms, and —CH ₂₋ contained in the alkanediyl group may be replaced with —O− or —CO−.
s represents an integer of 1-3. When s is 1 or more, two or more X ^1A are the same or different.
However, the upper limit of the total carbon number of the groups represented by the formulas (X ^1- A) to (X ^1- C) is 18. ]

A ¹ is preferably an alkanediyl group having 2 to 8 carbon atoms or an alkanetriyl group having 2 to 8 carbon atoms, and more preferably an alkanediyl group.
Alkanediyl groups having 1 to 8 carbon atoms include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group and hexane-1,6. Linear alkanediyl groups such as −diyl group, ethane-1,1-diyl group, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group Examples thereof include branched alkanediyl groups such as groups, 2-methylpropane-1,2-diyl groups, pentane-1,4-diyl groups and 2-methylbutane-1,4-diyl groups. Of these, an alkanediyl group having 2 to 6 carbon atoms is more preferable, and an alkanediyl group having 2 to 4 carbon atoms is even more preferable.

Examples of the alicyclic hydrocarbon group having 5 to 18 carbon atoms of R ³ include a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group. Among them, a cyclopentyl group, a cyclohexyl group and an adamantyl group are preferable, an adamantyl group and a cyclohexyl group are more preferable, and an adamantyl group is further preferable.
An alicyclic hydrocarbon is a Ketal ring in which two hydrogen atoms contained in an alicyclic hydrocarbon group may each be replaced with an oxygen atom and may contain a fluorine atom in which an alkandiyl group having 1 to 8 carbon atoms is combined. The two hydrogen atoms contained in one carbon atom constituting the group may be replaced with oxygen atoms, respectively. The ketal rings include * 1-O- (CH ₂ ) _2- O- * 2, * 1-O- (CH ₂ ) _3- O- * 2, and * 1-O- (CH ₂ ) _4- O-. * 2, * 1-O-CH _2- (CF ₂ ) _2- CH _2- O- * 2, * 1-O-CH _2- (CF ₂ ) _3- CH _2- O- * 2, * 1- O-CH _2- (CF ₂ ) _4- CH _2- O- * 2 and the like can be mentioned. Among them, * 1-O-CH _2- (CF ₂ ) _2- CH _2- O- * 2, * 1-O-CH _2- (CF ₂ ) _3- CH _2- O- * 2, * 1- _{O-CH 2 - (CF 2} ) 4 -CH 2 -O- * 2 are _{preferred, * 1-O-CH 2} - (CF 2) 2 -CH 2 -O- * 2, * 1-O-CH 2 -(CF ₂ ) _3- CH _2- O- * 2 is more preferable, and * 1-O-CH _2- (CF ₂ ) _2- CH _2- O- * 2 is even more preferable. * 1 and * 2 represent a bond, respectively, and * 1 and * 2 are bonded to the same carbon atom. Examples of the alkanediyl group forming the ketal ring include those similar to A ¹ above.

Examples of the anion (I) include the following anions. Of these, the anions represented by the formulas (Ia-1) to (Ia-8) are preferable.

In the salt (I) of the present invention, the above-mentioned cations and anions can be arbitrarily combined. Among them, the preferable salt (I) is the salt described below.

<Manufacturing method of salt (I)>
The salt (I) can be produced by reacting a salt represented by the formula (Ia) with a compound represented by the formula (Ib) in a solvent.
(In the formula, R ¹ , R ² , R ³ , m, n, s and A ¹ have the same meanings as described above. The same shall apply hereinafter.)
Examples of the solvent include chloroform, dichloromethane, acetonitrile and the like.

The salt (Ia) can be produced by reacting a salt represented by the formula (Ic) with a salt represented by the formula (Id) in a solvent.
Examples of the solvent include acetonitrile, chloroform, water and the like.
Examples of the salt represented by the formula (Id) include compounds represented by the following formula, which are easily available on the market.

The salt represented by the formula (Ic) is produced by reacting the salt represented by the formula (Ie) with the compound represented by the formula (If) in a solvent in the presence of a catalyst. can do.
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 (Ie) include salts represented by the following formula, which are easily available on the market.
Examples of the compound represented by the formula (If) include compounds represented by the following formula, which are easily available on the market.

The salt represented by the formula (Ie) is produced by reacting the salt represented by the formula (Ig) with the compound represented by the formula (Ih) in a solvent such as chloroform. You can also do it.
(In the formula, X represents a chlorine atom, a bromine atom or an iodine atom.)

Examples of the salt represented by the formula (Ig) include salts represented by the following formula, which are easily available on the market.

The compound represented by the formula (Ib) can be produced by reacting the compound represented by the formula (Ii) with the compound represented by the formula (Ij) in a solvent. it can.
Examples of the solvent include acetonitrile, chloroform and the like.

Examples of the compound represented by the formula (Ii) include compounds represented by the following formula, which are easily available on the market.

<Acid generator>
The acid generator of the present invention is also an acid generator containing a salt (I). The acid generator of the present invention may contain an acid generator known in the resist field other than the salt (I) (hereinafter, may be referred to as “acid generator (B)”). The acid generator (B) will be described later.
When the salt (I) and the acid generator (B) are contained as the acid generator, the ratio of the contents of the salt (I) and the acid generator (B) (mass ratio; salt (I): acid generation The agent (B)) is usually 1:99 to 99: 1, preferably 2:98 to 98: 2, more preferably 5:95 to 95: 5, and even more preferably 10:90 to 90:10. Is.

<Resist composition>
The resist composition of the present invention contains a resin containing a structural unit having an acid unstable group (hereinafter, may be referred to as "resin (A)") and a salt (I). The resist composition of the present invention may contain two or more kinds of salts (I).
The resist composition may contain an acid generator known in the field of resist. The resist composition preferably contains a quencher (hereinafter sometimes referred to as "quencher (C)") and preferably contains a solvent (hereinafter sometimes referred to as "solvent (E)").

<Salt (I)>
The resist composition of the present invention preferably contains the salt (I) as an acid generator. When the salt (I) is used as an acid generator, the content of the salt (I) is preferably 1 to 30% by mass, more preferably 1 to 20% by mass, based on the resin (A). It is preferably 2 to 15% by mass, more preferably 2 to 15% by mass.

<Acid generator (B)>
As the acid generator (B), a known acid generator can be used, and it may be an ionic acid generator or a nonionic acid generator. Preferably, it is an ionic acid generator. Examples of the ionic acid generator include an ionic acid generator composed of a combination of an anion (I) and a cation other than the cation (I), and an ionic acid generator composed of a combination of a known cation and a known anion. Be done.

Examples of the acid generator (B) include organic sulfonic acids and organic sulfonium salts. For example, the acid generation described in JP2013-68914, JP2013-3155, and JP2013-1905. Agents and the like can be mentioned. Specific examples thereof include those represented by the formulas (B1-1) to (B1-40), preferably formulas (B1-1), formulas (B1-2), and formulas containing an arylsulfonium cation. (B1-3), formula (B1-5), formula (B1-6), formula (B1-7), formula (B1-11), formula (B1-12), formula (B1-13), formula ( B1-14), formula (B1-20), formula (B1-21), formula (B1-23), formula (B1-24), formula (B1-25), formula (B1-26), formula (B1) -29), formula (B1-31), formula (B1-32), formula (B1-33), formula (B1-34), formula (B1-35), formula (B1-36), formula (B1-36) 37), the salt represented by any of the formula (B1-38), the formula (B1-39) or the formula (B1-40) is more preferable.

The acid generator (B) may contain two or more kinds.
The content of the acid generator (B) is preferably 1 to 30% by mass, more preferably 1 to 20% by mass, and 3 to 15% by mass with respect to the resin (A). Is even more preferable.
In the resist composition, when the salt (I) and the acid generator (B) are used as the acid generator, the total content of the salt (I) and the acid generator (B) is higher than that of the resin (A). It is preferably 1.5% by mass or more (more preferably 3% by mass or more), preferably 40% by mass or less (more preferably 35% by mass or less).

<Resin (A)>
The resin (A) has a structural unit having an acid unstable group (hereinafter, may be referred to as “structural unit (a1)”). Here, the "acid-unstable group" has a leaving group, and the leaving group is eliminated by contact with an acid, and the constituent unit is a hydrophilic group (for example, a hydroxy group, a carboxy group or a sulfhydryl group). It means a group that is converted into a structural unit having.
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 structural unit (I) constituting the resin (A) is a group represented by the formula (1) (hereinafter, may be referred to as a group (1)) and / or the formula (2). A group represented by (hereinafter, may be referred to as a group (2)) is preferable.
[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 R ^a2 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. ]
[In the formula (2), R ^a1'and R ^a2' each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^a3' represents a hydrocarbon group having 1 to 20 carbon atoms. 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. -CH ₂ − contained in the ring group may be replaced with −O − or −S−.
X represents an oxygen atom or a sulfur atom.
* Represents a bond with an oxygen atom or a sulfur atom. ]

^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 and an n-octyl group.
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 a ² 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), R ^a1 , R ^a2 and the carbon atom to which they are bonded form an adamantyl group, and R ^a3 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.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, an aryl group of a phenanthryl group 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). -Phenyl 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.), etc., alkyl-aryl groups (eg, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-propylphenyl group, 4- Isopropylphenyl group, 4-butylphenyl group, 4-t-butylphenyl group, 4-hexylphenyl group, 4-cyclohexylphenyl group, trill group, xsilyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-Methyl-6-ethylphenyl group, etc.), aryl-cycloalkyl group, cycloalkyl-aryl group (for example, p-adamantylphenyl group, etc.).
^{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 a resin (A) having a structural unit derived from a 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 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 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 independently 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.
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), and more. It is preferably an oxygen atom.
Examples of the alkyl group of R ^a02 , R ^a03 and R ^a04 , the alicyclic hydrocarbon group and the group combining these groups include the same groups as those mentioned in R ^{a1 to} R ^a3 of the formula (1).
The alkyl groups of R ^a02 , R ^a03 and R ^a04 preferably have 6 or less carbon atoms.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 and R ^a04 preferably have 8 or less carbon atoms, and 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 with these alkyl groups and the alicyclic hydrocarbon group. Examples of such groups include methylcyclohexyl group, dimethylcyclohexyl group, methylnorbornyl group, methyladamantyl group, cyclohexylmethyl group, methylcyclohexylmethyl group, adamantylmethyl group, 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.
^Ra04 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 groups of R ^a6 and R ^a7 preferably have 6 or less carbon atoms.
The alicyclic hydrocarbon groups of R ^a6 and R ^a7 are preferably alicyclic hydrocarbon groups having 8 or less carbon atoms, and more preferably 6 or less alicyclic hydrocarbon groups.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1'is preferably 0 or 1.

As the monomer (a1-0), for example, a monomer represented by any of the formulas (a1-0-1) to (a1-0-12) is preferable, and the monomers (a1-0-1) to (a1-0-1) are preferable. The monomer represented by any one of 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 monomers represented by any of the formulas (a1-2-1) to (a1-2-12), and the formulas (a1-2-3) and (a1). -2-4), the monomer represented by the formula (a1-2-9) or the formula (a1-2-10) is preferable, and the monomer represented by the formula (a1-2-3) or the formula (a1-2-9) is represented. The monomer to be used is more 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 unit.

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 .
R ^a13 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group formed by combining them, and the aliphatic hydrocarbon group and the said 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− or −O− or. 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, or 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.
The aliphatic hydrocarbon group having 1 to 8 carbon atoms of R ^a13 includes 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 R ^a13 include a cyclopentyl group, a cyclopropyl group, an adamantyl group, an adamantyl methyl group, a 1-adamantyl-1-methylethyl group, and a 2-oxo-oxolan-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 and n-hexyl group. 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 either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon groups include, for example, cyclopropyl group, cyclobutyl group and cyclopentyl. Examples thereof include cycloalkyl groups such as groups, cyclohexyl groups, methylcyclohexyl groups, dimethylcyclohexyl groups, cycloheptyl groups, cyclooctyl groups and cyclodecyl groups. 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). A resist pattern can be obtained at a 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 the structural unit (a1-3), the content thereof is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, based on the total structural unit of the resin (A). 20-85 mol% is more preferred.

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),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyloxy group or Represents a methacryloyloxy group.
la represents an integer from 0 to 4. When la is 2 or more, a plurality of Ra ^33s may be the same or different from each other.
R ^a34 and R ^a35 each independently 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 bonded to each other Then, together with CO to which they are bonded, a divalent heterocyclic group having 3 to 20 carbon atoms is formed, and the hydrocarbon group and −CH ₂ − contained in the divalent heterocyclic group are −O−. Alternatively, it may be replaced by −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 hydrocarbon group R ^a34 and R ^a35, include the same groups as R ^{a1 'and} R ^a2' of formula (2).
The R ^a36, include groups formed by alkyl groups having 1 to 18 carbon atoms, alicyclic hydrocarbon group having 3 to 18 carbon atoms, or these aromatic hydrocarbon group having 6 to 18 carbon atoms combined Be done.

In the formula (a1-4), R ^a32 is preferably a hydrogen atom.
R ^a33 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group and an ethoxy group, and even more preferably a methoxy group.
The la is preferably 0 or 1, more preferably 0.
R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably a hydrocarbon group having 1 to 12 carbon atoms, 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. It is a group to be formed, more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic aliphatic hydrocarbon group having 3 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. Alkyl group and the alicyclic hydrocarbon group in R ^a36 is unsubstituted is preferred. 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%, more preferably 15 to 90 mol%, based on all the structural units of the resin (A). 20 to 85 mol% is more preferable.

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 −, h3 represents an integer of 1 to 4, and * represents a bond with L ⁵¹ .
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ independently represent -O- or -S-, respectively.
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 a fluorine atom is preferable. 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'preferably an integer of 0 to 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 structural units represented by the formulas (a1-5-1) to (a1-5-2) are preferable, and they are represented by the formula (a1-5-1) or the formula (a1-5-2). Structural units are more preferred.

When the resin (A) has a structural unit (a1-5), the content thereof is preferably 1 to 50 mol%, more preferably 3 to 45 mol%, based on all the structural units of the resin (A). , 5-40 mol% is more preferred.

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). ) Is preferred, at least two or more are more preferred, and combinations 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 a structural unit (a1-1) or includes a structural unit (a1-2), and more preferably includes a 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 resist field can be used.
As the structural unit (s), a structural unit having a hydroxy group or a lactone ring and not having an acid unstable group is preferable. A structure having a hydroxy group and no acid-labile group (hereinafter sometimes referred to as "structural unit (a2)") and / or a lactone ring and no acid-labile 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). The structural unit (a2) may include 12 or more types.

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),
^Ra30 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 include a methyl group, an ethyl group, a propyl group, a butyl group, an n-pentyl group, an n-hexyl group and the like.
Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.
^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 even more 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 and the like. 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 of Ra ³¹ include an acetyl group, a propionyl group, a butyryl group and the like.
^Examples of the acyloxy group of Ra31 include an acetyloxy group, a propionyloxy group, a butyryloxy group and the like.
As the ma, 0, 1 or 2, is preferable, 0 or 1 is more preferable, and 0 is further preferable.

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 the deprotection treatment is performed, 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 is preferably 5 to 95 mol%, preferably 10 to 95 mol%, based on the total structural units of the resin (A). 80 mol% is more preferable, and 15 to 80 mol% is even more preferable.

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 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
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 Is -O-.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

Examples of the monomer for inducing the structural unit (a2-1) include the monomers described in JP-A-2010-204646. Monomers represented by any of the formulas (a2-1-1) to (a2-1-6) are preferable, and the monomers represented by any of the formulas (a2-1-1) to (a2-1-4) are 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 all the structural units of the resin (A). Yes, 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. 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). These may contain two or more kinds.

[In equation (a3-1),
^La4 represents −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 is an integer of 1 to 7.
) Represents a group. * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents an integer from 0 to 5. When p1 is 2 or more, a plurality of Ra ^21s are the same or different from each other.
In equation (a3-2),
^La5 represents −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 is an integer of 1 to 7.
) Represents a group. * Represents a bond with a carbonyl group.
R ^a19 represents a hydrogen atom or a methyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 represents an integer from 0 to 3. When q1 is 2 or more, a plurality of ^Ra22s are the same or different from each other.
In formula (a3-3),
^La6 represents −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 is an integer of 1 to 7.
) Represents a group. * 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, a plurality of ^Ra23s are 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.
R ^a25 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
L ^a7 is a single bond, ^* -L ^a8- O-, ^* -L ^a8- CO-O-, ^* -L ^a8- CO-O-L ^a9- CO-O- or ^* -L ^a8- O-CO Represents −L ^a9 −O−.
* Represents a bond with -O-.
^{La 8} and ^{La 9} represent an alkanediyl group having 1 to 6 carbon atoms independently of each other.
w1 represents an integer from 0 to 8. When w1 is 2 or more, the plurality of Ra ^25s may be the same or different from each other. ]

Examples of the aliphatic hydrocarbon group such as ^Ra21 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group.
Examples of the halogen atom of R ^a24 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. , It is 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, and 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 are each independently 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 each independently, preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are independently, preferably integers of 0 to 2, more preferably 0 or 1.

In formula (a3-4)
R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and further preferably a hydrogen atom or a methyl group.
^La7 is preferably single-bonded or ^{* -La8-} CO-O-, and more preferably single-bonded, -CH _2- CO-O- or -C ₂ H _4- CO-O-. ..
R ^a25 is preferably a carboxy group, a cyano group or a methyl group.
w1 is preferably an integer of 0 to 2, more preferably 0 or 1.
In particular, the formula (a3-4) is preferably the formula (a3-4)'.
(In the formula, R ^a24 and ^{La 7} have the same meanings as above.)

Examples of the monomer for deriving the structural unit (a3) include the monomers described in JP-A-2010-204646, the monomers described in JP-A-2000-122294, and the monomers 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 the formula (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 structural unit represented by the following formula (a3-4-1) ~ formula (a3-4-12), compound methyl group corresponding to R ^a24 is replaced by a hydrogen atom, the structural unit (a3-4 ) Can be given as a specific example.

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 all the structural units of the resin (A). , More preferably 10 to 60 mol%.
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 each relative to all the structural units of the resin (A). 5 to 60 mol% is preferable, 5 to 50 mol% is more preferable, and 10 to 50 mol% is further preferable.

<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, may be 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 ⁴ 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 ⁴ include a linear alcandiyl group such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, and an ethane-1,1-. Branched alkandiyl such as diyl group, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group The group is mentioned.

The perfluoroalkanediyl group of L ³ includes a difluoromethylene group, a perfluoroethylene group, a perfluoroethylfluoromethylene group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, and a 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.
The perfluorocycloalkanes diyl group L ^3, perfluoro-cyclohexane diyl group, perfluoro cyclopentanediyl group, perfluoro cycloheptane-diyl group, a perfluoroalkyl adamantane-diyl group and the like.

L ⁴ 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 following structural units.

Among the compounds represented by the formulas (a4-0-1) to (a4-0-16), the compounds in which the methyl group corresponding to R ⁵ is replaced with a hydrogen atom are also represented by the formula (a4-0). It can be mentioned as a specific example of the structural unit.

Examples of the structural unit (a4) include a structural unit represented by the formula (a4-1).
[In equation (a4-1),
R ^a41 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.
A ^a41 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 each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
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-, respectively.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
** and ** are the ^bonders, and ** is the ^bonder 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 and cyclic aliphatic hydrocarbon groups may have a carbon-carbon unsaturated bond, but are formed by chain and cyclic aliphatic saturated hydrocarbon groups and their combination. Groups are preferred. 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.

^Examples of the substituent of R ^a42 include a halogen atom and 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 R ^a42 .
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.
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 aliphatic hydrocarbon group of A ^a46 preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.
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 has a cyclohexyl group or an adamantyl group.

A more preferable structure of the partial structure represented by * -A ^a46- X ^a44- A ^a47 (* is a bond with a carbonyl group) 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 A ^a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and further preferably an ethylene group.

The aliphatic hydrocarbon group of A ^a42 , A ^a43 and A ^{a44 in} the group (a-g1) may have a carbon-carbon unsaturated bond, but is preferably an aliphatic saturated hydrocarbon group. .. 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 these substituents 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 ^f1 represents a hydrogen atom or a methyl group.
A ^f1 represents an alkanediyl group having 1 to 6 carbon atoms.
R ^f2 represents a hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

The alkanediyl group of A ^f1 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 ^f2 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 cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group and cyclodecyl group. 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 ^f2 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 fluorocycloalkyl group such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

As A ^f1 in the formula (a4-2), an alkanediyl group having 2 to 4 carbon atoms is preferable, and an ethylene group is more preferable.
As R ^f2 , an alkyl fluoride group having 1 to 6 carbon atoms is preferable.

[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 cyclic type aliphatic hydrocarbon group, and a divalent aliphatic hydrocarbon group formed by combining them. This aliphatic hydrocarbon group 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 pentandiyl 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 either a chain type or a cyclic type, and an aliphatic hydrocarbon group formed by combining these. This aliphatic hydrocarbon group 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 adamantylmethyl group, a norbornyl group, a norbornylmethyl group, a perfluoroadamantyl group, a perfluoroadamantylmethyl group and the like.

In the formula (a4-3), A ^f11 is an ethylene group is preferred.
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 structural units represented by the formulas (a4-1-1) to (a4-1-22).

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

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 each independently represent an integer of 1 to 6.
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 group having 1 to 10 carbon atoms having a fluorine atom is more preferable. Preferably, an alkyl group having 1 to 6 carbon atoms having a fluorine atom is more preferable.

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

When the resin (A) has a structural unit (a4), the content thereof is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, based on all the structural units of the resin (A). 10 mol% is more 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, and a divalent aliphatic saturated hydrocarbon group is preferable. ..
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 formula (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 and 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 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
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 ^{x 1} 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 ^{x 1} 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 ⁵⁵ 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 (a5-1-1) to (a5-1-18), 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 a structural unit (a5), the content thereof is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, based on all the structural units of the resin (A). More preferably ~ 15 mol%.

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.

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 15 mol% or more of structural units (particularly, structural units (a1-1)) derived from a monomer having an adamantane group with respect to the content of the structural units (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 preferable. Is 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 (X)>
The resist composition of the present invention may contain a resin other than the resin (A). As the resin other than the resin (A), a resin consisting of only the structural unit (s) and a resin containing the structural unit (a4) (however, the structural unit (a1) is not included. Hereinafter, the term "resin (X)" may be used. There is). Of these, a resin containing the structural unit (a4) 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, still more preferably 50 mol% or more, based on all the structural units of the resin (X). ..
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, and preferably 90% by mass or more and 99% by mass or less with respect to 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.

<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 two or more kinds.

<Quencher (C)>
Examples of the quencher (C) include a basic nitrogen-containing organic compound or a salt having a weaker acidity than the acid generated from the salt (I) and 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. Aliphatic amines include primary amines, secondary amines and tertiary amines.

As the quencher (C), 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, tri Hexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyl Didecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl ] Amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4' -Diamino-3,3'-diethyldiphenylmethane, piperazine, 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 can be mentioned, preferably diisopropylaniline, and particularly preferably 2,6-diisopropylaniline.

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

The acidity of a salt having a weaker acidity than the acid generated from the salt (I) and the acid generator (B) is indicated by the acid dissociation constant (pKa). A salt 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, preferably -1. It is a salt of <pKa <7, more preferably a salt of 0 <pKa <5. Examples of the salt having a weaker acidity than the acid generated from the acid generator (B) include a salt represented by the following formula, a weak acid intramolecular salt represented by the formula (D), and JP-A-2012-229206. Examples thereof include the salts described in JP-A-2012-6908, JP-A-2012-721109, 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)”).

[In formula (D),
R ^D1 and R ^D2 independently have 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 from 0 to 4, and when m'is 2 or more, a plurality of ^RD1s are the same or different, and when n'is 2 or more, a plurality of ^RD2s are. 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, t-butyl group, pentyl group, hexyl group and nonyl group.
The monovalent alicyclic hydrocarbon group may be either a monocyclic or polycyclic group, 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 an aryl group such as a phenyl group, a 1-naphthyl group, a 2-naphthyl group, an anthryl group, a biphenyl group and a phenanthryl group.
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). -Phenyl 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.), etc., alkyl-aryl groups (eg, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-propylphenyl group, 4- Isopropylphenyl group, 4-butylphenyl group, 4-t-butylphenyl group, 4-hexylphenyl group, 4-cyclohexylphenyl group, trill group, xsilyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-Methyl-6-ethylphenyl group, etc.), aryl-cycloalkyl group, cycloalkyl-aryl group (for example, p-adamantylphenyl group, etc.).

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), ^RD1 and ^RD2 independently have 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. 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 is preferable.
For m'and n', an integer of 0 to 2 is preferable, and 0 is more preferable, respectively. When m'is 2 or more, a plurality of R ^D1s are the same or different, and when n'is 2 or more, a plurality of R ^D2s are the same or different.

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

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%.

<Other ingredients>
The resist composition may contain components other than the above-mentioned components (hereinafter, may be referred to as "other components (F)"), if necessary. 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 composition after coating, the solvent is removed and a composition layer is formed. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called 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. Exposure light sources include those that emit ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and F ₂ excimer laser (wavelength 157 nm), and solid-state laser light sources (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 exposed composition layer is heat treated (so-called post-exposure bake) 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 a ketone solvent such as 2-hexanone and 2-heptanone; a glycol ether ester solvent such as propylene glycol monomethyl ether acetate; an ester solvent such as butyl acetate; and a glycol such as propylene glycol monomethyl ether. Examples thereof include ether solvents; amide solvents such as N and N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
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 further preferably substantially only the organic solvent.
As the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and substantially butyl acetate and / or 2 -It is even more preferable that it is only 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 is preferable.
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. It is suitable as a resist composition for an organic developer for ArF 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-2)
50 parts of the compound represented by the formula (I-2-a), 10.33 parts of the compound represented by the formula (I-2-b) and 350 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. Then, 0.20 part of copper (II) acetate was charged, refluxed at 80 ° C. for 2 hours, and concentrated. 440 parts of tert-butyl methyl ether was added to the recovered concentrate, stirred, and filtered to obtain 32.96 parts of a salt represented by the formula (I-2-c).

15.40 parts of the compound represented by the formula (I-2-d), 400 parts of chloroform, 200 parts of ion-exchanged water and 23.32 parts of the salt represented by the formula (I-2-c) are mixed and 23. The mixture was stirred at ° C. for 18 hours and separated. 86 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 3 times. The obtained organic layer was concentrated, and 200 parts of tert-butyl methyl ether was added to the obtained residue and stirred to remove the supernatant. By concentrating the obtained residue, 27.32 parts of a salt represented by the formula (I-2-e) was obtained.

14.76 parts of the compound represented by the formula (I-2-f), 59 parts of chloroform and 14.79 parts of the compound represented by the formula (I-2-g) were mixed and stirred at 60 ° C. for 1 hour. , Cooled to 23 ° C. To the obtained reaction solution, 27.04 parts of a salt represented by the formula (I-2-e) was added, and the mixture was further stirred at 23 ° C. for 18 hours. 235 parts of chloroform was added to the obtained reaction mass, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, the liquid was separated and the organic layer was taken out. 70 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 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 22.28 parts of a salt represented by the formula (I-2) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 383.1

Example 2: Synthesis of salt represented by formula (I-4)
1.91 parts of the compound represented by the formula (I-2), 0.73 parts of the compound represented by the formula (I-4-a) and 10 parts of 1,2-dichloroethane are mixed and mixed at 23 ° C. for 30 minutes. Stirred. To the obtained mixed solution, 0.01 part of p-toluenesulfonic acid was added, and the mixture was refluxed and stirred at 100 ° C. for 3 hours. The obtained reaction product was cooled to 23 ° C., 30 parts of chloroform and 10 parts of a 5% 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. 10 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. By concentrating the obtained organic layer, 0.39 part of the compound represented by the formula (I-4) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 527.1

Example 3: Synthesis of salt represented by formula (I-1)

13.70 parts of the compound represented by the formula (I-1-f), 59 parts of chloroform and 14.79 parts of the compound represented by the formula (I-2-g) were mixed and stirred at 60 ° C. for 1 hour. , Cooled to 23 ° C. To the obtained reaction solution, 27.04 parts of a salt represented by the formula (I-2-e) was added, and the mixture was further stirred at 23 ° C. for 18 hours. 235 parts of chloroform was added to the obtained mixture, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, the liquid was separated and the organic layer was taken out. 70 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 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 24.31 parts of a salt represented by the formula (I-1) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 369.1

Example 4: Synthesis of salt represented by formula (I-3)

14.92 parts of the compound represented by the formula (I-3-f), 59 parts of chloroform and 14.79 parts of the compound represented by the formula (I-2-g) were mixed and stirred at 60 ° C. for 1 hour. , Cooled to 23 ° C. To the obtained reaction solution, 27.04 parts of a salt represented by the formula (I-2-e) was added, and the mixture was further stirred at 23 ° C. for 18 hours. 235 parts of chloroform was added to the obtained reaction mixture, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, the liquid was separated and the organic layer was taken out. 70 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 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 22.78 parts of a salt represented by the formula (I-3) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 385.1

Example 5: Synthesis of salt represented by formula (I-10)
41.84 parts of the compound represented by the formula (I-10-a), 10.33 parts of the compound represented by the formula (I-2-b) and 350 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. Then, 0.20 part of copper (II) acetate was charged, refluxed at 80 ° C. for 2 hours, and concentrated. To the recovered concentrate, 440 parts of tert-butyl methyl ether was added, stirred, and filtered to obtain 25.44 parts of a salt represented by the formula (I-10-c).

15.40 parts of the compound represented by the formula (I-2-d), 400 parts of chloroform, 200 parts of ion-exchanged water and 21.57 parts of the salt represented by the formula (I-10-c) are mixed and 23. The mixture was stirred at ° C. for 18 hours and separated. 86 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 3 times. The obtained organic layer was concentrated, and 200 parts of tert-butyl methyl ether was added to the obtained residue and stirred to remove the supernatant. By concentrating the obtained residue, 25.68 parts of a salt represented by the formula (I-10-e) was obtained.

14.76 parts of the compound represented by the formula (I-2-f), 59 parts of chloroform and 14.79 parts of the compound represented by the formula (I-2-g) were mixed and stirred at 60 ° C. for 1 hour. , Cooled to 23 ° C. To the obtained reaction solution, 25.52 parts of a salt represented by the formula (I-10-e) was added, and the mixture was further stirred at 23 ° C. for 18 hours. 235 parts of chloroform was added to the obtained reaction mixture, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, the liquid was separated and the organic layer was taken out. 70 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 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 26.44 parts of a salt represented by the formula (I-10) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 211.1
MASS (ESI (-) Spectrum): M ^- 383.1

Example 6: Synthesis of salt represented by formula (I-12)
1.83 parts of the compound represented by the formula (I-10), 0.73 parts of the compound represented by the formula (I-4-a) and 10 parts of 1,2-dichloroethane are mixed and mixed at 23 ° C. for 30 minutes. Stirred. To the obtained mixed solution, 0.01 part of p-toluenesulfonic acid was added, and the mixture was refluxed and stirred at 100 ° C. for 3 hours. The obtained reaction product was cooled to 23 ° C., 30 parts of chloroform and 10 parts of a 5% 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. 10 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. By concentrating the obtained organic layer, 0.58 part of the compound represented by the formula (I-10) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 211.1
MASS (ESI (-) Spectrum): M ^- 527.1

Synthesis example 1: Synthesis of salt represented by the formula (IX-1)
15.40 parts of the compound represented by the formula (I-2-d), 400 parts of chloroform, 200 parts of ion-exchanged water and 17.19 parts of the salt represented by the formula (IX-1-a) are mixed and 23. The mixture was stirred at ° C. for 18 hours and separated. To the recovered organic layer, 100 parts of ion-exchanged water was added, the mixture was stirred at 23 ° C. for 30 minutes, and the solution was separated to take out the organic layer. This washing operation was repeated 3 times. The obtained organic layer was concentrated, and 100 parts of tert-butyl methyl ether was added to the obtained residue and stirred to remove the supernatant. By concentrating the obtained residue, 26.18 parts of a salt represented by the formula (IX-1-b) was obtained.
13.70 parts of the compound represented by the formula (IX-1-c), 50 parts of chloroform and 14.79 parts of the compound represented by the formula (IX-1-d) were mixed and stirred at 60 ° C. for 1 hour. , Cooled to 23 ° C. To the obtained reaction solution, 26.10 parts of a salt represented by the formula (IX-1-b) was added, and the mixture was further stirred at 23 ° C. for 18 hours. 200 parts of chloroform was added to the obtained reaction mixture, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. This was separated and the organic layer was taken out. 70 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 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 19.45 parts of a salt represented by the formula (IX-1) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 221.1
MASS (ESI (-) Spectrum): M ^- 369.1

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 was concentrated, 100 parts of tert-butyl methyl ether was added to the obtained residue, the mixture was stirred at 23 ° C. for 30 minutes, and filtered to obtain a salt represented by the formula (B1-21-c) 48. I got 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. .. To the obtained mixed solution, 0.21 part of copper (II) dibenzoate was added. Further, this was 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. 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 a 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 parts of copper (II) dibenzoate was added. Further, the mixture was 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. To the obtained residue, 50 parts of tert-butyl methyl ether was added, stirred, and filtered to obtain 6.84 parts of a salt represented by the formula (B1-22).

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 (a2-1-1) and a monomer (a3-4-2) are used, and the monomer is used. The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-1): monomer (a3-4-2)] is 45: 14: 2.5: 38. The mixture was mixed to 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 resulting resin was repulped with methanol / water mixed solvent, and filtrated to obtain a resin A1 having a weight-average molecular weight 7.8 × 10 ³ in 68% yield. 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 1.2% by mass of the total amount of the monomer 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 75 ° 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 resulting resin was repulped with methanol / water mixed solvent, by filtration, to obtain a resin X-1 having a weight-average molecular weight 7.8 × 10 ³ in 86% yield. 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 1.2% by mass of methyl isobutyl ketone 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 mixture 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
<Salt (I)>
I-2: Salt represented by the formula (I-2) I-4: Salt represented by the formula (I-4) I-1: Salt represented by the formula (I-1) I-3: Formula Salt represented by (I-3) I-10: Salt represented by formula (I-10) I-12: Salt represented by formula (I-12) <Acid generator>
B1-21: Salt represented by formula (B1-21) B1-22: Salt represented by formula (B1-22) IX-1: Salt represented by formula (IX-1) <Compound (D) ＞
D1: (manufactured by Tokyo Chemical Industry 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. Illumination], the exposure amount was changed stepwise and exposed using a mask for forming a trench pattern (pitch 120 nm / trench 40 nm). 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 using butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution by the dynamic dispense method at 23 ° C. for 20 seconds 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 salt, acid generator of the present invention and the resist composition containing the same 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)

A salt represented by the formula (I).
[In formula (I),
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 independently represent 1 or 2, respectively. When m is 2, the two R ^1s are the same or different, and when n is 2, the two R ^2s are the same or different.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic hydrocarbon group having 5 to 36 carbon atoms which may have a substituent.
A ¹ represents an (1 + s) -valent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms which may have a hydroxy group, and —CH ₂ − contained in the aliphatic saturated hydrocarbon group is −O. -Or-CO- may be replaced.
R ³ represents an alicyclic hydrocarbon group having 5 to 18 carbon atoms, are substituted with hydrogen atoms 2 turn, each oxygen atom contained in the alicyclic hydrocarbon group, the two oxygen atoms is 1 to carbon atoms ketal ring formed together with 8 alkanediyl group, the ketal ring to have a fluorine atom.
s represents an integer of 1-3. ] R ³ is an adamantyl group, are substituted with hydrogen atoms 2 turn, each oxygen atom contained in the adamantyl group, containing a fluorine atom such two oxygen atoms together with the alkanediyl group having 1 to 8 carbon atoms salt according to claim 1, wherein forming the non-ketal ring. The salt according to claim 1 or 2, wherein Ar is a phenyl group which may have a substituent. The salt according to any one of claims 1 to 3, wherein A ¹ is a (1 + s) -valent aliphatic saturated hydrocarbon group having 2 to 5 carbon atoms. An acid generator containing the salt according to any one of claims 1 to 4. A resist composition containing the acid generator according to claim 5 and a resin containing a structural unit having an acid unstable group. The resist composition according to claim 6, which contains a salt having a weaker acidity than the acid generated from the acid generator. The resist composition according to claim 6 or 7, further comprising a resin containing a structural unit having a fluorine atom. (1) A step of applying the resist composition according to any one of claims 6 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.