# Patent

## Title
Compound, resin, resist composition and method for producing resist pattern

## Abstract

A compound represented by formula (I), a resin including a structural unit derived from the compound and a resist composition including the resin:




wherein R1 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group in which a hydrogen atom may be replaced by a halogen atom, R2 represents a C1 to C12 fluorinated saturated hydrocarbon group, A1 represents a single bond, a C1 to C6 alkanediyl group or *-A3-X1-(A4-X2)a-(A5)b-, * represents a binding site to an oxygen atom, A2, A3, A4 and A5 each independently represent a C1 to C6 alkanediyl group, X1 and X2 each independently represent —O—, —CO—O— or —O—CO—, W1 represents a C5 to C18 divalent alicyclic hydrocarbon group, a represents 0 or 1, and b represents 0 or 1.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to Japanese Application No. 2014-228745 filed on Nov. 11, 2014. The entire disclosures of Japanese Application No. 2014-228745 is incorporated hereinto by reference.
BACKGROUND ART
1. Field of the Invention
The disclosure relates to a compound, a resin, a resist composition and a method for producing resist pattern.
2. Related Art
A resist composition which contains a resin having a structural unit below is described in Patent document of JP2013-238787A.




SUMMARY
The disclosure provides following inventions of <1> to <8>.
<1> A compound represented by formula (I):




wherein R1 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group in which a hydrogen atom may be replaced by a halogen atom,
R2 represents a C1 to C12 fluorinated saturated hydrocarbon group,
A1 represents a single bond, a C1 to C6 alkanediyl group or *-A3-X1-(A4-X2)a-(A5)b-,
* represents a binding site to an oxygen atom,
A2, A3, A4 and A5 each independently represent a C1 to C6 alkanediyl group,
X1 and X2 each independently represent —O—, —CO—O— or —O—CO—,
W1 represents a C5 to C18 divalent alicyclic hydrocarbon group,
a represents 0 or 1, and
b represents 0 or 1.
<2> The compound according to <1>, wherein
W1 is an adamantanediyl group or a cyclohexanediyl group.
<3> The compound according to <2>, wherein
the adamantanediyl group is any one of the groups represented by formulae (Ad-1) to (Ad-3);




wherein * is a binding site.
<4> The compound according to any one of <1> to <3>, wherein
A1 is a single bond.
<5> The compound according to any one of <1> to <4>, wherein
R2 is —(CH2)n—Rf or —CH(Rf1)(Rf2),
Rf represents a C1 to C6 perfluoroalkyl group,
Rf1 and Rf2 each independently represent a C1 to C6 perfluoroalkyl group, and
n represents an integer of 0 to 6.
<6> A resin which has a structural unit derived from the compound according to any one of <1> to <5>.
<7> A resist composition containing:
the resin according to <6>,
a resin having an acid-labile group, and
an acid generator.
<8> A method for producing a resist pattern includes steps (1) to (5);
(1) applying the resist composition according to <7> onto a substrate;
(2) drying the applied composition to form a composition layer;
(3) exposing the composition layer;
(4) heating the exposed composition layer; and
(5) developing the heated composition layer.


DETAILED DESCRIPTION OF THE DISCLOSURE
In the specification, the term “(meth)acrylic monomer” means a monomer having a structure of “CH2═CH—CO—” or “CH2═C(CH3)—CO—”, as well as “(meth)acrylate” and “(meth)acrylic acid” mean “an acrylate or methacrylate” and “an acrylic acid or methacrylic acid,” respectively. Herein, chain structure groups include those having a linear structure and those having a branched structure. Unless otherwise specified, the term “aliphatic hydrocarbon group” means a chain aliphatic hydrocarbon group. The indefinite articles “a” and “an” are taken as the same meaning as “one or more”.
The term “solid components” means components other than solvents in a resist composition.
<Compound (I)>
The compound of the disclosure, which is sometimes referred to as “compound (I)”, is a compound represented by formula (I);




wherein R1 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group in which a hydrogen atom may be replaced by a halogen atom,
R2 represents a C1 to C12 fluorinated saturated hydrocarbon group,
A1 represents a single bond, a C1 to C6 alkanediyl group or *-A3-X1-(A4-X2)a-(A5)b-,
* represents a binding site to an oxygen atom,
A2, A3, A4 and A5 each independently represent a C1 to C6 alkanediyl group,
X1 and X2 each independently represent —O—, —CO—O— or —O—CO—,
W1 represents a C5 to C18 divalent alicyclic hydrocarbon group,
a represents 0 or 1, and
b represents 0 or 1.
Examples of the alkyl group for R1 include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl groups, preferably include a C1 to C4 alkyl group, more preferably a methyl group or an ethyl group.
Examples of the halogen atom for R1 include fluorine, chlorine, bromine or iodine atom.
Examples of the alkyl group that may have a halogen atom for R1 include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoro-isopropyl, perfluorobutyl, perfluoro-sec-butyl, perfluoro-tert-butyl, perfluoropentyl, perfluorohexyl, perchloromethyl, perbromomethyl and periodomethyl groups.
R1 is preferably a hydrogen atom or a methyl group.
Examples of the C1 to C12 fluorinated saturated hydrocarbon group for R2 include a fluorinated alkyl group and a fluorinated alicyclic hydrocarbon group.
Specific examples thereof include difluoromethyl, trifluoromethyl, 1,1-difluoroethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, perfluoroethyl, 1,1,2,2-tetrafluoropropyl, 1,1,2,2,3,3-hexafluoropropyl, perfluoroethylmethyl, 1-(trifluoromethyl)-2,2,2-trifluoroethyl, 1-(trifluoromethyl)-2,2,3,3,3-pentafluoropropyl, 1-(perfluoroethyl)-2,2,3,3,3-pentafluoropropyl, 1-(trifluoromethyl)-1,2,2,2-tetrafluoroethyl, 1-(trifluoromethyl)-2,2,2-trifluoroethyl, perfluoropropyl, 1,1,2,2-tetrafluorobutyl, 1,1,2,2,3,3-hexafluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, perfluorobutyl, 1,1-bis(trifluoro)methyl-2,2,2-trifluoroethyl, 2-(perfluoropropyl)ethyl, 1,1,2,2,3,3,4,4-octafluoropentyl, perfluoropentyl, 1,1,2,2,3,3,4,4,5,5-decafluoropentyl, 1,1-bis(trifluoromethyl)2,2,3,3,3-pentafluoropropyl, 2-(perfluorobutyl)ethyl, 1,1,2,2,3,3,4,4,5,5-decafluorohexyl, 1,1,2,2,3,3,4,4,5,5,6,6-dodeca fluorohexyl, perfluoropentylmethyl, perfluorohexyl, perfluorocyclohexyl and perfluoroadamantyl groups.
Among these, R2 is preferably a C1 to C12 fluorinated alkyl group, and more preferably —(CH2)n—Rf or —CH(Rf1)(Rf2).
n represents an integer of 0 to 6, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, and still more preferably 1.
Rf represents a C1 to C6 perfluoroalkyl group, preferably a C1 to C4 perfluoroalkyl group, more preferably a C2 to C4 perfluoroalkyl group, and still more preferably a C3 to C4 perfluoroalkyl group.
Rf1 and Rf2 each independently represent a C1 to C6 perfluoroalkyl group, preferably a C1 to C4 perfluoroalkyl group, more preferably a C1 to C3 perfluoroalkyl group, and still more preferably a C1 to C2 perfluoroalkyl group.
In particular, R2 is preferably *—(CH2)n-Rf or —CH(Rf1)(Rf2) such as *—CHCF3CF3.
Examples of the C1 to C6 alkanediyl group for A1, A2, A3, A4 and A5 include a liner alkanediyl group such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl and hexane-1,6-diyl groups;
a branched alkanediyl group such as a group in which a liner alkanediyl group has, as a side chain, an alkyl group (e.g., a C1 to C4 alkyl group, i.e., methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl groups), for example, ethane-1,1-diyl, propane-1,2-diyl, butane-1,3-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl and 2-methylbutane-1,4-diyl groups.
Examples of *-A3-X1-(A4-X2)a-(A5)b- include *-A3-O—, *-A3-CO—O—, *-A3-CO—O-A5-, *-A3-O—CO—, *-A3-CO—O-A4-CO—O—, *-A3-CO—O-A4-CO—O-A5-, *-A3-O—CO-A4-O—, *-A3-O-A4-CO—O—, *-A3-CO—O-A4-O—CO— and *-A3-O—CO-A4-O—CO—. Among these, *-A3-O—, *-A3-CO—O—, *-A3-CO—O-A4-CO—O— and *-A3-O-A4-CO—O— are preferred. * represents a binding site to an oxygen atom.
A2, A3, A4 and A5 are preferably a C1 to C3 alkanediyl group. A2 is more preferably a C2 to C3 branched alkanediyl group, and still more preferably ethane-1,1-diyl group.
A1 is preferably a single bond or *-A3-CO—O—, more preferably a single bond, *—CH2—CO—O— or *—C2H4—CO—O—, still more preferably a single bond or *—CH2—CO—O—, and further more preferably a single bond.
Examples of the C5 to C18 divalent alicyclic hydrocarbon group for W1 include cyclopentanediyl, cyclohexanediyl, adamantanediyl and norbornanediyl groups. Among these, cyclohexanediyl and adamantanediyl groups are preferred, and adamantanediyl group is more preferred.
The adamantanediyl group is preferably a group represented by any one of formulae (Ad-1) to (Ad-3), more preferably a group represented by one of formulae (Ad-1) to (Ad-2), and still more preferably a group represented by formula (Ad-1). In formulae (Ad-1) to (Ad-3). In each of the formulae, * represents a binding site.




Examples of the compound (I) include the compounds represented by the following ones.
















Examples of the compound (I) include compounds represented by the formula in which a methyl group corresponding to R1 has been replaced by a hydrogen atom.
<Method for Producing the Compound (I)>
The compound (I) can be obtained by reacting a compound represented by formula (I-a) with a compound represented by formula (I-b) in presence of a catalyst in a solvent:




in which R1, R2, A1, A2 and W1 are as defined above.
Preferred examples of the solvent include chloroform, tetrahydrofuran and toluene.
Preferred examples of the catalyst include the basic catalyst such as pyridine and dimethylaminopyridine, and a known esterified catalyst such as acid catalyst and carbodiimide catalyst. The basic catalyst and the known esterified catalyst can be used as a catalyst for the reaction.
Examples of the compound represented by the formula (I-a) include compound represented by formula below which is available on the market.




Examples of the compound represented by the formula (I-b) include compounds represented by formulae below which are available on the market.




Examples of the carbodiimide catalyst include the salt represented by formula below which is available on the market.




<Resin (X)>

A resin of the disclosure has a structural unit derived from the compound (I) as described above, which is sometimes referred to as “structural unit (I)” (which is sometimes referred to as “resin (X)”). The resin (X) may have one kind of the structural unit (I), or two or more kinds of the structural units (I).
The resin (X) may further have another structural unit than the structural unit (I). Examples of another structural unit include a structural unit having a fluorine atom (which is sometimes referred to as “structural unit (a4)”), a structural unit having a non-leaving hydrocarbon group (which is sometimes referred to as “structural unit (a5)”), a structural unit having an acid-labile group as described later (which is sometimes referred to as “structural unit (a1)”) and a structural unit having no acid-labile group as described later (which is sometimes referred to as “structural unit (s)”), as well as a structural unit derived from an known monomer in this art.
When the resin (X) further has another structural unit than the structural unit (1), another structural unit is preferably the structural unit (a4) and/or the structural unit (a5).
<Structural Unit (a4)>
Examples of the structural unit (a4) include a structural unit represented by formula (a4-0).




In the formula (a4-0), R5 represents a hydrogen atom or a methyl group,
L5 represents a single bond or a C1 to C4 saturated aliphatic hydrocarbon group,
L3 represents a C1 to C8 perfluoroalkanediyl group, a C3 to C12 perfluorocycloalkanediyl group or a perfluoroadamantanediyl group, and
R6 represents a hydrogen atom or a fluorine atom.
Examples of the saturated aliphatic hydrocarbon group for L5 include C1 to C4 alkanediyl group, i.e., a liner alkanediyl group such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl; and a branched alkanediyl group such as a group in which a liner alkanediyl group has a side chain of an alkyl group (e.g., methyl and ethyl groups), for example, ethane-1,1-diyl, propane-1,2-diyl, butane-1,3-diyl, 2-methylpropane-1,3-diyl and 2-methylpropane-1,2-diyl groups.
L5 is preferably a single bond, a methylene or ethylene group, and more preferably a single bond or a methylene group.
Examples of the perfluoroalkanediyl group for L3 include difluoromethylene, perfluoroethylene, perfluoroethyl fluoromethylene, perfluoropropane-1,3-diyl, a perfluoropropane-1,2-diyl, perfluoropropane-2,2-diyl, perfluorobutane-1,4-diyl, perfluorobutane-2,2-diyl, perfluorobutane-1,2-diyl, perfluoropentane-1,5-diyl, perfluoropentane-2,2-diyl, perfluoropentane-3,3-diyl, perfluorohexane-1,6-diyl, perfluorohexane-2,2-diyl, perfluorohexane-3,3-diyl, perfluoroheptane-1,7-diyl, perfluoroheptane-2,2-diyl, perfluoroheptane-3,4-diyl, perfluoroheptane-4,4-diyl, perfluorooctane-1,8-diyl, perfluorooctane-2,2-diyl, perfluorooctane-3,3-diyl and perfluorooctane-4,4-diyl groups.
Examples of the perfluoro cycloalkanediyl group for L3 include perfluorocyclohexanediyl, perfluorocyclopentanediyl, perfluorocycloheptanediyl and perfluoroadamantanediyl groups.
L3 is preferably a C1 to C6 perfluoroalkanediyl group, more preferably a C1 to C3 perfluoroalkanediyl group.
Examples of the structural unit (a4-0) include the following ones.










Examples of the structural unit (a4-0) include the structural units represented by the above formulae in which a methyl group corresponding to R5 has been replaced by a hydrogen atom.
Examples of the structural unit (a4) include the structural units represented by formula (a4-1):




wherein Ra41 represents a hydrogen atom or a methyl group,
Ra42 represents an optionally substituted C1 to C20 hydrocarbon group where a methylene group may be replaced by an oxygen atom or a carbonyl group, and
Aa41 represents an optionally substituted C1 to C6 alkanediyl group or a group represented by formula (a-g1),




wherein s represents 0 or 1,
Aa42 and Aa44 each independently represent an optionally substituted C1 to C5 aliphatic hydrocarbon group,
Aa43 represents a single bond or an optionally substituted C1 to C5 aliphatic hydrocarbon group, and
Xa41 and Xa42 each independently represent —O—, —CO—, —CO—O— or —O—CO—,
provided that the total carbon number contained in Aa42, Aa43, Aa44, Xa41 and Xa42 is 7 or less,
at least one of Aa41 and Ra42 has a halogen atom as a substituent, and
* and ** represent a binding site, and * represents a binding site to —O—CO—Ra42.
The hydrocarbon group for Ra42 includes a chain and a cyclic aliphatic hydrocarbon groups, an aromatic hydrocarbon group and a combination thereof.
The chain and the cyclic aliphatic hydrocarbon group may have a carbon-carbon unsaturated bond, and is preferably a chain and a cyclic saturated aliphatic hydrocarbon group. Examples of the saturated aliphatic hydrocarbon group include a liner or branched alkyl group, a monocyclic or polycyclic alicyclic hydrocarbon group, and an aliphatic hydrocarbon group formed by combining the alkyl group and the alicyclic hydrocarbon group.
Examples of the chain aliphatic hydrocarbon group include an alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, and 2-ethylhexyl groups, preferably include a C1 to C4 alkyl group, more preferably a methyl group or an ethyl group, and still more preferably a methyl group.
Examples of the alicyclic hydrocarbon group include a cycloalkyl group such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl groups; and polycyclic hydrocarbon groups such as decahydronaphtyl, adamantyl and norbornyl groups as well as groups below. * represents a binding site.




Examples of the aromatic hydrocarbon group include an aryl group such as phenyl, naphthyl, anthryl, biphenyl, phenanthryl and fluorenyl groups.
The hydrocarbon group for Ra42 is preferably a chain and a cyclic aliphatic hydrocarbon groups, and a combination thereof. The hydrocarbon group may have a carbon-carbon unsaturated bond, is preferably a chain and a cyclic saturated aliphatic hydrocarbon groups, and a combination thereof.
Examples of the substituent for Ra42 include a halogen atom or a group represented by formula (a-g3):

*-Xa43-Aa45  (a-g3)

wherein Xa43 represent an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group,
Aa45 represents a C1 to C17 aliphatic hydrocarbon group that has a halogen atom, and
* represents a binding site.
Examples of the halogen atom for the substituent include fluorine, chlorine, bromine or iodine atom, and preferably a fluorine atom.
Examples of the aliphatic hydrocarbon group for Aa45 include the same ones as those for Ra42.
Ra42 is preferably an aliphatic hydrocarbon group that may have a halogen atom, and more preferably an alkyl group having a halogen atom and/or an aliphatic hydrocarbon group having the group represented by the formula (a-g3).
When Ra42 is an aliphatic hydrocarbon group having a halogen atom, an aliphatic hydrocarbon group having a fluorine atom is preferred, a perfluoroalkyl group or a perfluorocycloalkyl group are more preferred, a C1 to C6 perfluoroalkyl group is still more preferred, a C1 to C3 perfluoroalkyl group is particularly preferred.
Examples of the perfluoroalkyl group include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroheptyl and perfluorooctyl groups. Examples of the perfluorocycloalkyl group include perfluorocyclohexyl group.
When Ra42 is an aliphatic hydrocarbon group having the group represented by the formula (a-g3), the total carbon number contained in the aliphatic hydrocarbon group including the group represented by the formula (a-g3) is preferably 15 or less, more preferably 12 or less. The number of the group represented by the formula (a-g3) is preferably one when the group represented by the formula (a-g3) is the substituent.
The aliphatic hydrocarbon group having the group represented by the formula (a-g3) is more preferably a group represented by formula (a-g2):

*-Aa46-Xa44-Aa47  (a-g2)

wherein Aa46 represents a C1 to C17 aliphatic hydrocarbon group that may have a halogen atom,
Xa44 represent a carbonyloxy group or an oxycarbonyl group,
Aa47 represents a C1 to C17 aliphatic hydrocarbon group that may have a halogen atom,
provided that the total carbon number contained in Aa46, Xa44 and Aa47 is 18 or less,
at least one of Aa46 and Aa47 has a halogen atom, and
* represents a binding site to a carbonyl group.
The aliphatic hydrocarbon group for Aa46 has preferably 1 to 6 carbon atoms, more preferably 1 to 3, carbon atoms.
The he aliphatic hydrocarbon group for Aa47 has preferably 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms. Aa47 is more preferably a cyclohexyl group or an adamantyl group.
Preferred examples of *-Aa46-Xa44-Aa47 include the following ones.




Examples of the alkanediyl group for Aa41 include a liner alkanediyl group such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl and hexane-1,6-diyl groups;
a branched alkanediyl group such as propane-1,2-diyl, butan-1,3-diyl, 2-methylpropane-1,2-diyl, 1-methylbutane-1,4-diyl, 2-methylbutane-1,4-diyl groups.
Examples of the substituent on the alkanediyl group for Aa41 include a hydroxy group and a C1 to C6 alkoxy group.
Examples of the substituent on the alkanediyl for Aa41 include a hydroxy group and a C1 to C6 alkoxy group.
Aa41 is preferably a C1 to C4 alkanediyl group, more preferably a C2 to C4 alkanediyl group, and still more preferably ethylene group.
In the group represented by the formula (a-g1) (which is sometimes referred to as “group (a-g1)”), examples of the aliphatic hydrocarbon group for Aa42, Aa43 and Aa44 include methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, 1-methylpropane-1,3-diyl, 2-methylpropane-1,3-diyl and 2-methylpropane-1,2-diyl groups.
Examples of the substituent in the aliphatic hydrocarbon group for Aa42, Aa43 and Aa44 include a hydroxy group and a C1 to C6 alkoxy group.
s is preferably 0.
Examples of the group (a-g1) in which Xa42 represents an oxygen atom include the following ones. In the formula, * and ** each represent a binding site, and ** represents a binding site to —O—CO—Ra42.




Examples of the group (a-g1) in which Xa42 represents a carbonyl group include the following ones.




Examples of the group (a-g1) in which Xa42 represents a carbonyloxy group include the following ones.




Examples of the group (a-g1) in which Xa42 represents an oxycarbonyl group include the following ones.




The structural unit represented by the formula (a4-1) is preferably structural units represented by formula (a4-2) and formula (a4-3):




wherein Rf1a represents a hydrogen atom or a methyl group,
Af1 represent a C1 to C6 alkanediyl group, and
Rf12a represents a C1 to C10 hydrocarbon group that has a fluorine atom.
Examples of the alkanediyl group for Af1 include a liner alkanediyl group such as methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl and hexane-1,6-diyl groups;
a branched alkanediyl group such as 1-methylpropane-1,3-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, 1-methylbutane-1,4-diyl and 2-methylbutane-1,4-diyl groups.
The hydrocarbon group for Rf2a includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group. The aliphatic hydrocarbon group includes a chain and cyclic groups, and a combination thereof. The aliphatic hydrocarbon group is preferably an alkyl group and a cyclic aliphatic hydrocarbon group.
Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and 2-ethylhexyl groups.
Examples of the cyclic aliphatic hydrocarbon group include any of a monocyclic group and a polycyclic group. Examples of the monocyclic alicyclic hydrocarbon group include a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl, and cyclodecyl groups. Examples of the polycyclic hydrocarbon groups includes decahydronaphthyl, adamantyl, 2-alkyladamantane-2-yl, 1-(adamantane-1-yl)alkane-1-yl, norbornyl, methylnorbornyl and isobornyl groups.
Examples of the hydrocarbon group having a fluorine atom for Rf2a include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Specific examples of an alkyl group having a fluorine atom include a fluorinated alkyl group such as difluoromethyl, trifluoromethyl, 1,1-difluoroethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, perfluoroethyl, 1,1,2,2-tetrafluoropropyl, 1,1,2,2,3,3-hexafluoropropyl, perfluoroethylmethyl, 1-(trifluoromethyl)-1,2,2,2-tetrafluoroethyl, perfluoropropyl, 1-(trifluoromethyl)-2,2,2-trifluoroethyl, perfluoropropyl, 1,1,2,2-tetrafluorobutyl, 1,1,2,2,3,3-hexafluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, perfluorobutyl, 1,1-bis(trifluoro)methyl-2,2,2-trifluoroethyl, 2-(perfluoropropyl)ethyl, 1,1,2,2,3,3,4,4-octafluoropentyl, perfluoropentyl, 1,1,2,2,3,3,4,4,5,5-decafluoropentyl, 1,1-bis(trifluoromethyl)2,2,3,3,3-pentafluoropropyl, 2-(perfluorobutyl)ethyl, 1,1,2,2,3,3,4,4,5,5-decafluorohexyl, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl, perfluoropentylmethyl and perfluorohexyl groups.
Examples of the alicyclic hydrocarbon group having a fluorine atom include a fluorinated cycloalkyl group such as perfluorocyclohexyl and perfluoroadamantyl groups.
In the formula (a4-2), Af1 is preferably a C2 to C4 alkanediyl group, and more preferably an ethylene group.
Rf2a is preferably a C1 to C6 fluorinated alkyl group.




In the formula (a4-3), Rf11 represents a hydrogen atom or a methyl group,
Af11 represent a C1 to C6 alkanediyl group,
Af13 represents a C1 to C18 aliphatic hydrocarbon group that may have a fluorine atom,
Xf12 represents an oxycarbonyl group or a carbonyloxy group,
Af14 represents a C1 to C17 aliphatic hydrocarbon group that may have a fluorine atom, and
provided that at least one of Af13 and Af14 represents an aliphatic hydrocarbon group having a fluorine atom.
Examples of the alkanediyl group for Af11 include the same ones as those for Af1.
Examples of the aliphatic hydrocarbon group for Af13 include any of a divalent liner or cyclic aliphatic hydrocarbon group, or a divalent aliphatic hydrocarbon group formed by combination thereof. The aliphatic hydrocarbon group may have a carbon-carbon unsaturated bond, and is preferably a saturated aliphatic hydrocarbon group.
The aliphatic hydrocarbon group that may have a fluorine atom for Af13 is preferably the saturated aliphatic hydrocarbon group that may have a fluorine atom, and more preferably a perfluoroalkandiyl group.
Examples of the divalent liner aliphatic hydrocarbon that may have a fluorine atom include an alkanediyl group such as methylene, ethylene, propanediyl, butanediyl and pentanediyl groups; a perfluoroalkanediyl group such as difluoromethylene, perfluoroethylene, perfluoropropanediyl, perfluorobutanediyl and perfluoropentanediyl groups.
The divalent cyclic aliphatic hydrocarbon group that may have a fluorine atom is any of monocyclic or polycyclic group.
Examples monocyclic aliphatic hydrocarbon group include cyclohexanediyl and perfluorocyclohexanediyl groups.
Examples polycyclic aliphatic hydrocarbon group include adamantanediyl, norbornanediyl, and perfluoroadamantanediyl groups.
Examples of the aliphatic hydrocarbon group for Af14 include any of a chain or a cyclic aliphatic hydrocarbon group, or a combination thereof. The aliphatic hydrocarbon group may have a carbon-carbon unsaturated bond, and is preferably a saturated aliphatic hydrocarbon group.
The aliphatic hydrocarbon group that may have a fluorine atom of Af14 is preferably the saturated aliphatic hydrocarbon group that may have a fluorine atom.
Examples of the chain aliphatic hydrocarbon group that may have a halogen atom include trifluoromethyl, difluoromethyl, methyl, perfluoromethyl, 1,1,1-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, ethyl, perfluoropropyl, 1,1,1,2,2-pentafluoropropyl, propyl, perfluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, butyl, perfluoropentyl, 1,1,1,2,2,3,3,4,4-nonafluoropentyl, pentyl, hexyl, perfluorohexyl, hepthyl, perfluoroheptyl, octyl and perfluorooctyl groups.
The cyclic aliphatic hydrocarbon group that may have a fluorine atom may be any of a monocyclic group and a polycyclic group. Examples of the group containing the monocyclic aliphatic hydrocarbon group include cyclopropylmethyl, cyclopropyl, cyclobutylmethyl, cyclopentyl, cyclohexyl and perfluorocyclohexyl groups. Examples of the group containing the polycyclic aliphatic hydrocarbon group includes adamantyl, adamantylmethyl, norbornyl, norbornylmethyl, perfluoroadamantyl and perfluoroadamantylmethyl groups
In the formula (a4-3), Af11 is preferably an ethylene group.
The aliphatic hydrocarbon group for Af13 is preferably a C1 to C6 aliphatic hydrocarbon group, more preferably a C2 to C3 aliphatic hydrocarbon group.
The aliphatic hydrocarbon group for Af14 is preferably a C3 to C12 aliphatic hydrocarbon group, more preferably a C3 to C10 aliphatic hydrocarbon group. Among these, Af14 is preferably a group containing a C3 to C12 alicyclic hydrocarbon group, more preferably cyclopropylmethyl, cyclopentyl, cyclohexyl, norbornyl and adamantyl groups.
Examples of the structural unit (a4-2) include structural units represented by formula (a4-1-1) to formula (a4-1-22).



















Examples of the structural unit (a4-3) include structural units presented by formula (a4-1′-1) to formula (A4-1′-22).




























Examples of the structural unit (a4) include a structural unit presented by formula (a4-4):




wherein Rf21 represents a hydrogen atom or a methyl group,
Af21 represents *—(CH2)j1—, *—(CH2)j2—O—(CH2)j3— or *—(CH2)j4—CO—O—(CH2)j5—, where * represents a binding site to an oxygen atom,
j1 to j5 each independently represents an integer of 1 to 6, and
Rf22 represents a C1 to C10 hydrocarbon group having a fluorine atom.
Examples of the hydrocarbon group having a fluorine atom for Rf22 include the same ones as those for Rf2 in the formula (a4-2). Rf22 is preferably a C1 to C10 alkyl group having a fluorine atom or a C3 to C10 alicyclic hydrocarbon group having a fluorine atom, more preferably a C1 to C10 alkyl group having a fluorine atom, and still more preferably a C1 to C6 alkyl group having a fluorine atom.
In the formula (a4-4), Af21 is preferably —(CH2)j 1—, more preferably a methylene group or an ethylene group, and still more preferably a methylene group.
Examples of the structural unit represented by the formula (a4-4) include the following ones.













<Structural Unit (a5)>

Examples of the non-leaving hydrocarbon group in the structural unit (a5) include a liner or branched, or a cyclic hydrocarbon group. Among these, the structural unit (a5) is preferably a structural unit containing an alicyclic hydrocarbon group.
Examples of the structural unit (a5) include the following ones.
















Examples of the structural units (a5) include structural units represented by the above formulae in which a methyl group corresponding to, for example, Rf21 in the formula (a4-4) has been replaced by a hydrogen atom.
The proportion of the structural unit (I) is preferably 10 to 100% by mole, more preferably 20 to 100% by mole, still more preferably 30 to 100% by mole, and further more preferably 40 to 100% by mole, particularly preferably 50 to 100% by mole, with respect to the total structural units (100% by mole) of the resin (X).
When the resin (X) further has the structural unit (a4), the proportion thereof is preferably 1 to 20% by mole, more preferably 2 to 15% by mole, still more preferably 3 to 10% by mole, with respect to the total structural units (100% by mole) of the resin (X).
When the resin (X) further has the structural unit (a5), the proportion thereof is preferably 10 to 80% by mole, more preferably 20 to 75% by mole, still more preferably 30 to 70% by mole, further more preferably 40 to 60% by mole, with respect to the total structural units (100% by mole) of the resin (X).
The resin (X) can be produced by a known polymerization method, for example, radical polymerization method, using one or more species of monomers inducing the structural units as described above. The proportion of the structural unit in the resin (X) can be adjusted by changing the amount of a monomer used in polymerization.
The weight average molecular weight of the resin (X) is preferably 8,000 or more (more preferably 10,000 or more), and 80,000 or less (more preferably 60,000 or less). In the present specification, the weight average molecular weight is a value determined by gel permeation chromatography using polystyrene as the standard product. The detailed condition of this analysis is described in Examples.
<Resist Composition>
The resist composition of the disclosure contains the resin (X), a resin (A) having an acid-labile group and an acid generator (which is sometimes referred to as “acid generator (B)”).
The resist composition preferably further contains a quencher (which is sometimes referred to as “quencher (C)”) or a solvent (which is sometimes referred to as “solvent (E)”), more preferably further contains the quencher (C) and the solvent (E).
Herein, the resin (A) has an acid-labile group but no structural unit (I).
<Resin (A)>
The resin (A) has a structural unit having an acid-labile group (which is sometimes referred to as “structural unit (a1)”). The resin (A) preferably further has 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 (which is sometimes referred to as “structural unit (s)”), a structural unit other than the structural unit (a1) and the structural unit (s) (which is sometimes referred to as “structural unit (t)”), as well as the structural unit derived from an known monomer in this art as described above.
Herein, the resin (A) has the structural unit (a1) but no structural unit (I).
<Structural Unit (a1)>
The structural unit (a1) is derived from a monomer having an acid-labile group (which is sometimes referred to as “monomer (a1)”). Here the “acid-labile group” means a group having a leaving group which is detached by contacting with an acid resulting in forming a hydrophilic group such as a hydroxy or carboxy group.
In the resin (A), the acid-labile group contained in the structural unit (a1) is preferably the following group (1) and/or group (2):




wherein Ra1 to Ra3 each independently represent a C1 to C8 alkyl group, a C3 to C20 alicyclic hydrocarbon group or a combination thereof, or Ra1 and Ra2 may be bonded together with a carbon atom bonded thereto to form a C3 to C20 divalent hydrocarbon group;
na represents an integer of 0 or 1; and
* represents a binding site;




wherein Ra1′ and Ra2′ each independently represent a hydrogen atom or a C1 to C12 hydrocarbon group, Ra3′ represents a C1 to C20 hydrocarbon group, or Ra2′ and Ra3′ may be bonded together with a carbon atom and X bonded thereto to form a divalent C3 to C20 (or 4 to 21-membered) heterocyclic group, and a methylene group contained in the hydrocarbon group or the divalent heterocyclic group may be replaced by an oxygen atom or a sulfur atom;
X represents —O— or —S—; and
* represents a binding site.
Examples of the alkyl group for Ra1 to Ra3 include methyl, ethyl, propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl and n-octyl groups.
Examples of the alicyclic hydrocarbon group for Ra1 to Ra3 include monocyclic groups such as a cycloalkyl group, i.e., cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl groups; and polycyclic groups such as decahydronaphtyl, adamantyl and norbornyl groups as well as the following groups. In each of the formulae, * represents a binding site.




The carbon number of the alicyclic hydrocarbon group for Ra1 to Ra3 is preferably 3 to 16.
Examples of groups combining the alkyl group and the alicyclic hydrocarbon group include methyl cyclohexyl, dimethyl cyclohexyl, methyl norbornyl and methyl adamantly, cyclohexylmethyl, methyl cyclohexylmethyl, adamantylmethyl and norbornylmethyl groups.
na is preferably 0.
When Ra1 and Ra2 is bonded together to form a divalent hydrocarbon group, examples of the group —C(Ra1)(Ra2)(Ra3) include the following groups. The carbon number of the divalent hydrocarbon group is preferably 3 to 12. In each of the formulae, * represent a binding site to —O—.




In each formula, Ra3 is as defined above.
Specific examples of the group represented by the formula (1) include, for example,
1,1-dialkylalkoxycarbonyl group (a group in which Ra1 to Ra3 are alkyl groups, preferably tert-butoxycarbonyl group, in the formula (1)),
2-alkyladamantane-2-yloxycarbonyl group (a group in which Ra1, Ra2 and a carbon atom form adamantyl group, and Ra3 is alkyl group, in the formula (1)), and
1-(adamantane-1-yl)-1-alkylalkoxycarbonyl group (a group in which Ra1 and Ra2 are alkyl group, and Ra3 is adamantyl group, in the formula (1)).
The hydrocarbon group for Ra1′ to Ra3′ includes any of an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group and a group formed by combining thereof.
Examples of the alkyl group and the alicyclic hydrocarbon group are the same examples as described above.
Examples of the aromatic hydrocarbon group include an aryl group such as phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl, phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.
Examples of the divalent heterocyclic group formed by bonding with Ra2′ and Ra3′ with a carbon atom and X bonded thereto include the following groups.




In each formula, Ra1′ and X are as defined above.
At least one of Ra1′ and Ra2′ is preferably a hydrogen atom.
Specific examples of the group represented by the formula (2) include the following groups. In each of the formulae, * represents a binding site.




The monomer (a1) is preferably a monomer having an acid-labile group and an ethylenically unsaturated bond, and more preferably a (meth)acrylic monomer having an acid-labile group.
Among the (meth)acrylic monomer having an acid-labile group, a monomer having a C5 to C20 alicyclic hydrocarbon group is preferred. When a resin (A) including a structural unit derived from a monomer (a1) having a bulky structure such as the alicyclic hydrocarbon group is used for a resist composition, the resist composition having excellent resolution tends to be obtained.
Examples of a structural unit derived from the (meth)acrylic monomer having the group represented by the formula (1) preferably include structural units represented by formula (a1-0), formula (a1-1) and formula (a1-2) below. These may be used as a single structural unit or as a combination of two or more structural units. The structural unit represented by formula (a1-0), the structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2) are sometimes referred to as “structural unit (a1-0)”, “structural unit (a1-1)” and “structural unit (a1-2)”), respectively, and monomers inducing the structural unit (a1-0), the structural unit (a1-1) and the structural unit (a1-2) are sometimes referred to as “monomer (a1-0)”, “monomer (a1-1)” and “monomer (a1-2)”), respectively:




wherein La01 represents —O— or *—O—(CH2)k01—CO—O—,
k01 represents an integer of 1 to 7,
* represents a binding site to —CO—,
Ra01 represents a hydrogen atom or a methyl group, and
Ra02, Ra03 and Ra04 each independently represent a C1 to C8 alkyl group, a C3 to C18 alicyclic hydrocarbon group or a combination thereof.
La01 is preferably an —O— or *—O—(CH2)k01—CO—O— in which k01 is preferably an integer of 1 to 4, more preferably an integer of 1, more preferably an —O—.
Examples of the alkyl group and an alicyclic hydrocarbon group, and the combination thereof for Ra02, Ra03 and Ra04 are the same examples as the group described in Ra1 to Ra3 in the formula (1).
The alkyl group of Ra02, Ra03 and Ra04 is preferably a C1 to C6 alkyl group.
The alicyclic hydrocarbon group of RaO2, Ra03 and Ra04 is preferably a C3 to C8 alicyclic hydrocarbon group, more preferably a C3 to C6 alicyclic hydrocarbon group.
The group formed by combining the alkyl group and the alicyclic hydrocarbon group has preferably 18 or less of carbon atom. Examples of those groups include methylcyclohexyl, dimethylcyclohexyl, methylnorbornyl, methyladamantyl, cyclohexylmethl, methylcyclohexyl methyladamantylmethyl, adamantylmethyl and norbornylmethyl groups.
Ra02 and Ra03 is preferably a C1 to C6 alkyl group, more preferably a methyl group or an ethyl group.
Ra04 is preferably a C1 to C6 alkyl group or a C5 to C12 alicyclic hydrocarbon group, more preferably methyl, ethyl, cyclohexyl or adamantyl group.




In each formula, La1 and La2 each independently represent —O— or *—O—(CH2)k1—CO—O—,
k1 represents an integer of 1 to 7,
* represents a binding site to —CO—,
Ra4 and Ra5 each independently represent a hydrogen atom or a methyl group,
Ra6 and Ra7 each independently represent a C1 to C8 alkyl group, a C3 to C18 alicyclic hydrocarbon group or a combination thereof,
m1 represents an integer of 0 to 14,
n1 represents an integer of 0 to 10, and
n1′ represents an integer of 0 to 3.
La1 and La2 are preferably —O— or *—O—(CH2)k1′—CO—O— in which k1′ represents an integer of 1 to 4 and more preferably 1, and still more preferably —O—.
Ra4 and Ra5 are preferably a methyl group.
Examples of the alkyl group and an alicyclic hydrocarbon group, and the combination thereof for Ra6 and Ra7 are the same examples as the group described in Ra1 to Ra3 in the formula (1).
The alkyl group of Ra6 and Ra7 is preferably a C1 to C6 alkyl group.
The alicyclic hydrocarbon group of Ra6 and Ra7 is preferably a C3 to C8 alicyclic hydrocarbon group, and more preferably a C3 to C6, alicyclic hydrocarbon group.
m1 is preferably an integer of 0 to 3, and more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, and more preferably 0 or 1.
n1′ is preferably 0 or 1.
Examples of the structural unit (a1-0) preferably include structural units represented by formula (a1-0-1) to formula (a1-0-12), and more preferably structural units represented by formula (a1-0-1) to formula (a1-0-10) below.










Examples of the structural units (a1-0) include structural units in which a methyl group corresponding to Ra01 has been replaced by a hydrogen atom.
Examples of the monomer (a1-1) include monomers described in JP 2010-204646A. Among these, the monomers are preferably monomers represented by formula (a1-1-1) to formula (a1-1-8), and more preferably monomers represented by formula (a1-1-1) to formula (a1-1-4) below.







Examples of the monomer (a1-2) include 1-methylcyclopentane-1-yl(meth)acrylate, 1-ethylcyclopentane-1-yl(meth)acrylate, 1-methylcyclohexane-1-yl(meth)acrylate, 1-ethylcyclohexane-1-yl(meth)acrylate, 1-ethylcycloheptane-1-yl(meth)acrylate, 1-ethylcyclooctane-1-yl(meth)acrylate, 1-isopropylcyclopentane-1-yl(meth)acrylate and 1-isopropylcyclohexane-1-yl(meth)acrylate. Among these, the monomers are preferably monomers represented by formula (a1-2-1) to formula (a1-2-12), and more preferably monomers represented by formula (a1-2-3), formula (a1-2-4), formula (a1-2-9) and formula (a1-2-10), and still more preferably monomer represented by formula (a1-2-3) and formula (a1-2-9) below.







When the resin (A) has the structural unit (a1-0) and/or the structural unit (a1-1) and/or the structural unit (a1-2), the total proportion thereof is generally 10 to 95% by mole, preferably 15 to 90% by mole, and more preferably 20 to 85% by mole, with respect to the total structural units (100% by mole) of the resin (A).
Further, examples of the structural unit (a1) having the group (1) include a structural unit presented by formula (a1-3). The structural unit represented by formula (a1-3) is sometimes referred to as “structural unit (a1-3)”. The monomer from which the structural unit (a1-3) is derived is sometimes referred to as “monomer (a1-3)”.




In the formula, Ra9 represents a carboxy group, a cyano group, a —COORa13, a hydrogen atom or a C1 to C3 aliphatic hydrocarbon group that may have a hydroxy group,
Ra13 represents a C1 to C8 aliphatic hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group or a group formed by combining thereof, a hydrogen atom contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced by a hydroxy group, a methylene group contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced by an oxygen atom or a carbonyl group, and
Ra10, Ra11 and Ra12 each independently represent a C1 to C8 alkyl group, a C3 to C20 alicyclic hydrocarbon group or a group formed by combining thereof, or Ra10 and Ra11 may be bonded together with a carbon atom bonded thereto to form a C2 to C20 divalent hydrocarbon group.
Here, examples of —COORa13 group include a group in which a carbonyl group is bonded to the alkoxy group, such as methoxycarbonyl and ethoxycarbonyl groups.
Examples of the aliphatic hydrocarbon group that may have a hydroxy group for Ra9 include methyl, ethyl, propyl, hydroxymethy and 2-hydroxyethyl groups.
Examples of the C1 to C8 aliphatic hydrocarbon group for Ra13 include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, 2-ethylhexyl and n-octyl groups.
Examples of the C3 to C20 alicyclic hydrocarbon group for Ra13 include cyclopentyl, cyclopropyl, adamantyl, adamantylmethyl, 1-(adamantyl-1-yl)-methylethyl, 2-oxo-oxolane-3-yl, 2-oxo-oxolane-4-yl groups.
Examples of the alkyl group for Ra10 to Ra12 include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, 2-ethylhexyl and n-octyl groups.
Examples of the alicyclic hydrocarbon group for Ra10 and Ra12 include monocyclic groups such as a cycloalkyl group, i.e., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl and cyclodecyl groups; and polycyclic groups such as decahydronaphtyl, adamantyl, 2-alkyl-2-adamantyl, 1-(adamantane-1-yl)alkane-1-yl, norbornyl, methyl norbornyl and isobornyl groups.
When Ra10 and Ra11 are bonded together with a carbon atom bonded thereto to form a divalent hydrocarbon group, examples of the group-C(Ra10)(Ra11)(Ra12) include the following groups.




In each formula, Ra12 is as defined above.
Examples of the monomer (a1-3) include tert-butyl 5-norbornene-2-carboxylate, 1-cyclohexyl-1-methylethyl 5-norbornene-2-carboxylate, 1-methylcyclohexyl 5-norbornene-2-carboxylate, 2-methy-2-adamantane-2-yl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantane-2-yl 5-norbornene-2-carboxylate, 1-(4-methycyclohexyl)-1-methylethyl 5-norbornene-2-carboxylate, 1-(4-hydroxycyclohexyl)-1-methylethyl 5-norbornene-2-carboxylate, 1-methyl-(4-oxocyclohexyl)-1-ethyl 5-norbornene-2-carboxylate, and 1-(1-adamantane-1-yl)-1-methylethyl 5-norbornene-2-carboxylate.
The resin (A) including the structural unit (a1-3) can improve the resolution of the obtained resist composition because it has a bulky structure, and also can improve a dry-etching tolerance of the obtained resist composition because of incorporated a rigid norbornene ring into a main chain of the resin (A).
When the resin (A) has the structural unit (a1-3), the proportion thereof is preferably 10% by mole to 95% by mole, more preferably 15% by mole to 90% by mole, and still more preferably 20% by mole to 85% by mole, with respect to the total structural units constituting the resin (A) (100% by mole).
Examples of a structural unit (a1) having the group (2) include a structural unit represented by formula (a1-4). The structural unit is sometimes referred to as “structural unit (a1-4)”.




In the formula, Ra32 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group that may have a halogen atom,
Ra33 in each occurrence independently represent a halogen atom, a hydroxy group, a C1 to C6 alkyl group, a C1 to C6 alkoxy group, a C2 to C4 acyl group, a C2 to C4 acyloxy group, an acryloyloxy group or methacryloyloxy group,
la represents an integer 0 to 4,
Ra34 and Ra35 each independently represent a hydrogen atom or a C1 to C12 hydrocarbon group; and
Ra36 represents a C1 to C20 hydrocarbon group, or Ra35 and Ra36 may be bonded together with a C—O bonded thereto to form a divalent C3 to C20 heterocyclic group, and a methylene group contained in the hydrocarbon group or the divalent heterocyclic group may be replaced by an oxygen atom or a sulfur atom.
Examples of the alkyl group of Ra32 and Ra33 include methyl, ethyl, propyl, isopropyl, butyl, pentyl and hexyl groups. The alkyl group is preferably a C1 to C4 alkyl group, and more preferably a methyl group or an ethyl group, and still more preferably a methyl group.
Examples of the halogen atom of Ra32 and Ra33 include a fluorine, chlorine, bromine and iodine atoms.
Examples of the alkyl group that may have a halogen atom include trifluoromethyl, difluoromethyl, methyl, perfluoroethyl, 1,1,1-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, ethyl, perfluoropropyl, 1,1,1,2,2-pentafluoropropyl, propyl, perfluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, butyl, perfluoropentyl, 1,1,1,2,2,3,3,4,4-nonafluoropentyl, n-pentyl, n-hexyl and n-perfluorohexyl groups.
Examples of an alkoxy group include methoxy, ethoxy, propoxy, butoxy, pentyloxy and hexyloxy groups. The alkoxy group is preferably a C1 to C4 alkoxy group, more preferably a methoxy group or an ethoxy group, and still more preferably methoxy group.
Examples of the acyl group include acetyl, propionyl and butyryl groups.
Examples of the acyloxy group include acetyloxy, propionyloxy and butyryloxy groups.
Examples of the hydrocarbon group for Ra34 and Ra35 are the same examples as described in Ra1′ to Ra2′ in the formula (2).
Examples of hydrocarbon group for Ra36 include a C1 to C18 alkyl group, a C3 to C18 alicyclic hydrocarbon group, a C6 to C18 aromatic hydrocarbon group or a group formed by combining thereof.
In the formula (a1-4), Ra32 is preferably a hydrogen atom.
Ra33 is preferably a C1 to C4 alkoxy group, more preferably a methoxy group or an ethoxy group, and still more preferably a methoxy group.
la is preferably 0 or 1, and more preferably 0.
Ra34 is preferably a hydrogen atom.
Ra35 is preferably a C1 to C12 hydrocarbon group, and more preferably a methyl group or an ethyl group.
The hydrocarbon group for Ra36 is preferably a C1 to C18 alkyl group, a C3 to C18 alicyclic hydrocarbon group, a C6 to C18 aromatic hydrocarbon group or a combination thereof, and more preferably a C1 to C18 alkyl group, a C3 to C18 alicyclic hydrocarbon group or a C7 to C18 aralkyl group. The alkyl group and the alicyclic hydrocarbon group for Ra36 are preferably unsubstituted. When the aromatic hydrocarbon group of Ra36 has a substituent, the substituent is preferably a C6 to C10 aryloxy group.
Examples of the monomer from which the structural unit (a1-4) is derived include monomers described in JP 2010-204646A. Among these, the monomers are preferably the following monomers represented by formula (a1-4-1) to formula (a1-4-7), and more preferably monomers represented by formula (a1-4-1) to formula (a1-4-5).







When the resin (A) has the structural unit (a1-4), the proportion thereof is preferably 10% by mole to 95% by mole, more preferably 15% by mole to 90% by mole, and still more preferably 20% by mole to 85% by mole, with respect to the total structural units constituting the resin (A) (100% by mole).
Examples of the structural unit having an acid-labile group include a structural unit represented by formula (a1-5). The structural unit is sometimes referred to as “structural unit (a1-5)”.




In the formula (a1-5), Ra8 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group that may have a halogen atom,
Za1 represent a single bond or *—(CH2)h3—CO-L54-,
h3 represents an integer of 1 to 4,
* represents a binding site to L51,
L51, L52, L53 and L54 each independently represent —O— or —S—,
s1 represents an integer of 1 to 3, and
s1′ represents an integer of 0 to 3.
In the formula (a1-5), Ra8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group;
L51 is preferably —O—;
L52 and L53 are independently preferably —O— or —S—, and more preferably one is —O— and another is —S—.
s1 is preferably 1;
s1′ is preferably an integer of 0 to 2;
Za1 is preferably a single bond or *—CH2—CO—O—. * represents a binding site to L51.
Examples of a monomer from which the structural unit (a1-5) is derived include a monomer described in JP 2010-61117A. Among these, the monomers are preferably monomers represented by formula (a1-5-1) to formula (a1-5-4), and more preferably monomers represented by formula (a1-5-1) to formula (a1-5-2) below.




When the resin (A) has the structural unit (a1-5), the proportion thereof is preferably 1% by mole to 50% by mole, more preferably 3% by mole to 45% by mole, and still more preferably 5% by mole to 40% by mole, with respect to the total structural units (100% by mole) constituting the resin (A).
The resin (A) has, as the structural unit (a1), preferably at least one, more preferably two or more structural units selected from the structural unit (a1-0), the structural unit (a1-1), the structural unit (a1-2) and the structural unit (a1-5), a combination of the structural unit (a1-1) and the structural unit (a1-2), a combination of the structural unit (a1-1) and the structural unit (a1-5), a combination of the structural unit (a1-1) and the structural unit (a1-0), a combination of the structural unit (a1-2) and the structural unit (a1-0), a combination of the structural unit (a1-5) and the structural unit (a1-0), a combination of the structural unit (a1-0), the structural unit (a1-1) and the structural unit (a1-2), a combination of the structural unit (a1-0), the structural unit (a1-1) and the structural unit (a1-5), and further still preferably a combination of the structural unit (a1-1) and the structural unit (a1-2), a combination of the structural unit (a1-1) and the structural unit (a1-5).
<Structural Unit (s)>
The structural unit (s) is derived from a monomer having no acid-labile group (which monomer is sometimes referred to as “monomer (s)”).
As the monomer (s) from which the structural unit (s) is derived, a known monomer having no acid-labile group can be used.
As the structural unit (s), a structural unit having a hydroxy group or a lactone ring but having no acid-labile group is preferred. When a resin including the structural unit derived from a structural unit having a hydroxy group but having no acid-labile group (such structural unit is sometimes referred to as “structural unit (a2)”) and/or a structural unit having a lactone ring but having no acid-labile group (such structural unit is sometimes referred to as “structural unit (a3)”) is used, the adhesiveness of resist to a substrate and resolution of resist pattern tend to be improved.
<Structural Unit (a2)>
The structural unit (a2) having a hydroxy group may be an alcoholic hydroxy group or a phenolic hydroxy group.
When KrF excimer laser lithography (248 nm), or high-energy irradiation such as electron beam or EUV (extreme ultraviolet) is used for the resist composition, using the structural unit having a phenolic hydroxy group as the structural unit (a2) is preferred.
When ArF excimer laser lithography (193 nm) is used, using the structural unit having an alcoholic hydroxy group as the structural unit (a2) is preferred, and using the structural unit represented by formula (a2-1) is more preferred.
The structural unit (a2) may be used as a single structural unit or as a combination of two or more structural units.
When the resin (A) includes the structural unit (a2), the total proportion thereof is preferably 5% by mole to 95% by mole, more preferably 10% by mole to 80% by mole, and still more preferably 15% by mole to 80% by mole, with respect to the total structural units (100% by mole) constituting the resin (A).
Examples of the structural unit (a2) having a phenolic hydroxy group include a structural unit represented by formula (a2-0) (which is sometimes referred to as “structural unit (a2-0)”).




wherein Ra30 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group that may have a halogen atom,
Ra31 in each occurrence independently represents a halogen atom, a hydroxy group, a C1 to C6 alkyl group, a C1 to C6 alkoxy group, a C2 to C4 acyl group, a C2 to C4 acyloxy group, an acryloyloxy group or an methacryloyloxy group, and
ma represents an integer 0 to 4.
Examples of the alkyl group include methyl, ethyl, propyl, butyl, n-pentyl and n-hexyl groups.
Examples of the halogen atom include a chlorine atom, a fluorine atom and bromine atom.
Examples of the C1 to C6 alkyl group that may have a halogen atom for Ra30 include trifluoromethyl, difluoromethyl, methyl, perfluoromethyl, 1,1,1-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, ethyl, perfluoropropyl, 1,1,1,2,2-pentafluoropropyl, propyl, perfluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, butyl, perfluoropentyl, 1,1,1,2,2,3,3,4,4-nonafluoropentyl, n-pentyl, n-hexyl and n-perfluorohexyl groups.
Ra30 is preferably a hydrogen atom or a C1 to C4 alkyl group, and more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group.
Examples of the alkoxy group for Ra31 include methoxy, ethoxy, propoxy, butoxy, pentyloxy, and hexyloxy groups. Ra31 is preferably a C1 to C4 alkoxy group, more preferably a methoxy group or an ethoxy group, and still more preferably a methoxy group.
Examples of the acyl group include acetyl, propionyl and butyryl groups.
Examples of the acyloxy group include acetyloxy, propionyloxy and butyryloxy groups.
ma is preferably 0, 1 or 2, more preferably 0 or 1, still more preferably 0.
The structural unit (a2-0) having a phenolic hydroxy group is preferably a structural unit represented below.




Among these, a structural unit represented by formula (a2-0-1) and formula (a2-0-2) are preferred.
Examples of a monomer from which the structural unit (a2-0) is derived include monomers described in JP2010-204634A.
The resin (A) which has the structural units (a2-0) having a phenolic hydroxy group can be produced, for example, by polymerizing a monomer where its phenolic hydroxy group has been protected with a suitable protecting group, followed by deprotection. The deprotection is carried in such a manner that an acid-labile group in the structural unit (a1) is significantly impaired. Examples of the protecting group for a phenolic hydroxy group include an acetyl group.
When the resin (A) further has the structural unit (a2-0) having the phenolic hydroxy group, the proportion thereof is preferably 5% by mole to 95% by mole, more preferably 10% by mole to 80% by mole, and still more preferably 15% by mole to 80% by mole, with respect to the total structural units (100% by mole) constituting the resin (A).
Examples of the structural unit (a2) having an alcoholic hydroxy group include the structural unit represented by formula (a2-1) (which is sometimes referred to as “structural unit (a2-1)”).




In the formula (a2-1), La3 represents —O— or *—O—(CH2)k2—CO—O—,
k2 represents an integer of 1 to 7,
* represents a binding site to —CO—,
Ra14 represents a hydrogen atom or a methyl group,
Ra15 and Ra16 each independently represent a hydrogen atom, a methyl group or a hydroxy group, and
o1 represents an integer of 0 to 10.
In the formula (a2-1), La3 is preferably —O—, —O—(CH2)f1—CO—O—, here f1 represents an integer of 1 to 4, and more preferably —O—.
Ra14 is preferably a methyl group.
Ra15 is preferably a hydrogen atom.
Ra16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, and more preferably an integer of 0 or 1.
Examples of the monomer from which the structural unit (a2-1) is derived include monomers described in JP 2010-204646A. Among these, the structural units (a2-1) are preferably structural units represented by formula (a2-1-1) to formula (a2-1-6), more preferably structural units represented by formula (a2-1-1) to formula (a2-1-4), and still more preferably structural units represented by formula (a2-1-1) and formula (a2-1-3).







When the resin (A) has the structural unit (a2-1) having an alcoholic hydroxy group, the proportion thereof is generally 1% by mole to 45% by mole, preferably 1% by mole to 40% by mole, more preferably 1% by mole to 35% by mole, and still more preferably 2% by mole to 20% by mole, with respect to the total structural units (100% by mole) constituting the resin (A).
<Structural Unit (a3)>
The lactone ring included in the structural unit (a3) may be a monocyclic ring such as β-propiolactone, γ-butyrolactone, δ-valerolactone, or a condensed ring of monocyclic lactone ring with another ring. Examples of the lactone ring preferably include γ-butyrolactone, adamantane lactone, or bridged ring with γ-butyrolactone.
Examples of the structural unit (a3) include structural units represented by any of formula (a3-1), formula (a3-2), formula (a3-3) and formula (a3-4). These structural units may be used as a single unit or as a combination of two or more units.




In each formula, La4 represents *—O— or *—O—(CH2)k3—CO—O—, k3 represents an integer of 1 to 7, * represents a binding site to a carbonyl group,
Ra18 represents a hydrogen atom or a methyl group,
Ra21 in each occurrence represents a C1 to C4 aliphatic hydrocarbon group, and
p1 represents an integer of 0 to 5,
La5 represents *—O— or *—O—(CH2)k3—CO—O—, k3 represents an integer of 1 to 7, * represents a binding site to a carbonyl group,
Ra19 represents a hydrogen atom or a methyl group,
Ra22 in each occurrence represents a carboxy group, a cyano group or a C1 to C4 aliphatic hydrocarbon group,
q1 represents an integer of 0 to 3,
La6 represents *—O— or *—O—(CH2)k3—CO—O—, k3 represents an integer of 1 to 7, * represents a binding site to a carbonyl group,
Ra20 represents a hydrogen atom or a methyl group,
Ra23 in each occurrence represents a carboxy group, a cyano group or a C1 to C4 aliphatic hydrocarbon group, and
r1 represents an integer of 0 to 3,
Ra24 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group that may have a halogen atom,
La7 represents a single bond, *-La8-O—, *-La8-CO—O—, *-La8-CO—O-La9-CO—O—, or *-La8-O—CO-La9-O—; * represents a binding site to a carbonyl group, and
La8 and La9 each independently represent a C1 to C6 alkanediyl group.
Examples of the aliphatic hydrocarbon group for Ra21, Ra2 and Ra23 include an alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl and tert-butyl groups.
Examples of the halogen atom for Ra24 include fluorine, chlorine, bromine and iodine atoms;
Examples of the alkyl group for Ra24 include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl groups. The alkyl group is preferably a C1 to C4 alkyl group, more preferably a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom of Ra24 include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoro-isopropyl, perfluorobutyl, perfluoro-sec-butyl, perfluoro-tert-butyl, perfluoropentyl, perfluorohexyl, trichloromethyl, tribromomethyl and triiodomethyl groups.
Examples of the alkanediyl group of La8 and La9 include methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, butane-1,3-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl and 2-methylbutane-1,4-diyl groups.
In the formulae (a3-1) to (a3-3), La4 to La6 is independently preferably —O—, *—O—(CH2)k3′—CO—O—, here k3′ represents an integer of 1 to 4, more preferably —O— or *—O—CH2—CO—O—, and still more preferably *—O—.
Ra18 to Ra21 is preferably a methyl group.
Ra22 and Ra23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are independently preferably an integer of 0 to 2, and more preferably 0 or 1.
In the formula (a3-4), Ra24 is preferably a hydrogen atom or a C1 to C4 alkyl group, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group.
La7 is preferably a single bond or *-La8-CO—O—, and more preferably a single bond, —CH2—CO—O— or —C2H4—CO—O—.
Examples of the monomer from which the structural unit (a3) is derived include monomers described in JP 2010-204646A, monomers described in JP2000-122294A and monomers described in JP2012-41274A. The structural units (a3) are preferably structural units represented by formula (a3-1-1) to formula (a3-1-4), formula (a3-2-1) to formula (a3-2-4), formula (a3-3-1) to formula (a3-3-4), formula (a3-4-1) to formula (a3-4-12), more preferably structural units represented by formula (a3-1-1), formula (a3-1-2), formula (a3-2-3), formula (a3-2-4), formula (a3-4-1) to formula (a3-4-12), still more preferably structural units represented by formula (a3-4-1) to formula (a 3-4-12), further still preferably formula (a3-4-1) to formula (a3-4-6) below.



















Examples of the structural unit (a3) include the structural units represented by the formula (a3-4-1) to the formula (a3-4-12) in which a methyl group corresponding to Ra24 has been replaced by a hydrogen atom.
When the resin (A) further has the structural units (a3), the total proportion thereof is preferably 5% by mole to 70% by mole, more preferably 10% by mole to 65% by mole, still more preferably 10% by mole to 60% by mole, with respect to the total structural units (100% by mole) constituting the resin (A).
The proportion each of the formula (a3-1), the formula (a3-2), the formula (a3-3) and the formula (a3-4) is preferably 5% by mole to 60% by mole, more preferably 5% by mole to 50% by mole, still more preferably 10% by mole to 50% by mole, with respect to the total structural units (100% by mole) constituting the resin (A).
<Other Structural Unit (t)>
The resin (A) may further have a structural unit other than the structural unit (a1) and the structural unit (s) described above (which is sometimes referred to as “structural unit (t)”). Examples of the structural unit (t) include the structural unit (a4), the structural unit (a5) described above, other than the structural unit (a2) and the structural unit (a3).
When the resin (A) has the structural unit (a4), the proportion thereof is preferably 1 to 20% by mole, more preferably 2 to 15% by mole, and still more preferably 3 to 10% by mole, with respect to the total structural units (100% by mole) of the resin (A).
When the resin (A) has the structural unit (a5), the proportion thereof is preferably 1 to 30% by mole, more preferably 2 to 20% by mole, and still more preferably 3 to 15% by mole, with respect to the total structural units (100% by mole) of the resin (A).
The resin (A) is preferably a resin having the structural unit (a1) and the structural unit (s), that is, a copolymer of the monomer (a1) and the monomer (s). In this copolymer, the structural unit (a1) is preferably at least one of the structural unit (a1-0), the structural unit (a1-1), the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group) and the structural unit (a1-5), and more preferably is the structural unit (a1-1) or the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or 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 the structural unit represented by the formula (a2-1). The structural unit (a3) is preferably the structural unit having at least one of a γ-butyrolactone ring, a bridged ring including a γ-butyrolactone ring or an adamantane lactone ring.
The proportion of the structural unit derived from the monomer having an adamantyl group (in particular, the structural unit (a1-1)) in the resin (A) is preferably 15% by mole or more with respect to the structural units (a1). As the mole ratio of the structural unit derived from the monomer having an adamantyl group increases within this range, the dry etching resistance of the resulting resist improves.
The resin (A) can be produced by a known polymerization method, for example, radical polymerization method, using one or more species of monomers inducing the structural units as described above. The proportion of the structural unit in the resin (A) can be adjusted by changing the amount of a monomer used in polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, and still more preferably 3,000 or more), and 50,000 or less (more preferably 30,000 or less, and still more preferably 15,000 or less).
The proportion of the resin (X) is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, and still more preferably 1 to 40 parts by mass, in particular preferably 2 to 30 parts by mass, with respect to the resin (A) (100 parts by mass).
The total proportion of the resin (A) and the resin (X) is preferably 80% by mass to 99% by mass, more preferably 90% by mass to 99% by mass, with respect to the total amount of solid components of the resist composition.
The proportion of the solid components in the resist composition and that of the resins in the solid components can be measured with a known analytical method such as liquid chromatography and gas chromatography.
<Acid Generator (B)>
The acid generator (B) may be an ionic acid generator or a non-ionic acid generator. Examples of the nonionic compounds for the acid generator include organic halogenated compounds; sulfonate esters, e.g. 2-nitrobenzylester, aromatic sulfonates, oximesulfonate, N-sulfonyloxyimide, sulfonyloxyketone, and diazonaphtoquione 4-sulfonate; sulfones, e.g., disulfone, ketosulfone, and sulfonium diazomethane. The ionic compounds for the acid generator include onium salts having an onium cation, e.g., diazonium salts, phosphonium salts, sulfonium salts and iodonium salts. Examples of the anions of onium salt include a sulfonic acid anion, a sulfonylimide anion, sulfonylmethide anion.
As the acid generator, the compounds giving an acid by radiation can be used, which are mentioned in JPS63-26653A1, JPS55-164824A1, JPS62-69263A1, JPS63-146038A1, JPS63-163452A1, JPS62-153853A1, JPS63-146029A1, U.S. Pat. Nos. 3,779,778B1, 3,849,137B1, DE3914407 and EP126,712A1. The acid generator for the photoresist composition can be produced by the method described in the above-mentioned documents.
In the resist composition of the disclosure, the acid generator (B) may be used as a single salt or as a combination of two or more of salts.
The acid generator (B) is preferably a fluorine-containing compound, more preferably a salt represented by formula (B1) (which is sometimes referred to as “acid generator (B1)”):




wherein Q1 and Q2 each respectively represent a fluorine atom or a C1 to C6 perfluoroalkyl group,
Lb1 represents a C1 to C24 divalent saturated hydrocarbon group where a methylene group may be replaced by an oxygen atom or a carbonyl group and a hydrogen atom may be replaced by a hydroxyl group or fluorine atom, and
Y represents an optionally substituted methyl group or an optionally substituted C3 to C18 alicyclic hydrocarbon group, and a methylene group contained in the alicyclic hydrocarbon group may be replaced by an oxygen atom, a carbonyl group or a sulfonyl group, and
Z+ represents an organic cation.
Examples of the perfluoroalkyl group of Q1 and Q2 include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoro-isopropyl, perfluorobutyl, perfluoro-sec-butyl, perfluoro-tert-butyl, perfluoropentyl and perfluorohexyl groups.
Q1 and Q2 independently are preferably a trifluoromethyl group or a fluorine atom, and both of Q1 and Q2 are more preferably a fluorine atom.
Examples of the divalent saturated hydrocarbon group for Lb1 include any of a chain or a branched alkanediyl group, a divalent saturated monocyclic- or a polycyclic alicyclic hydrocarbon group, and a combination thereof.
Specific examples of the chain alkanediyl group include methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl groups.
Specific examples of the branched chain alkanediyl group include ethane-1,1-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-2,2-diyl, pentane-1,4-diyl, pentane-2,4-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl and 2-methylbutane-1,4-diyl groups.
Specific examples of the saturated monocyclic alicyclic hydrocarbon group include a cycloalkanediyl group such as cyclobutan-1,3-diyl, cyclopentan-1,3-diyl, cyclohexane-1,4-diyl and cyclooctan-1,5-diyl groups.
Specific examples of the saturated polycyclic alicyclic hydrocarbon group include norbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl and adamantane-2,6-diyl groups.
Examples of the divalent saturated hydrocarbon group for Lb1 in which a methylene group has been replaced by oxygen atom or a carbonyl group include the following groups represented by formula (b1-1) to formula (b1-3):




wherein Lb2 represents a single bond or a C1 to C22 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom;
Lb3 represents a single bond or a C1 to C22 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group, and a methylene group may be replaced by an oxygen atom or a carbonyl group;
provided that the total carbon number contained in the group of Lb2 and Lb3 is 22 or less;
Lb4 represents a single bond or a C1 to C22 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom;
Lb5 represents a single bond or a C1 to C22 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group, and a methylene group may be replaced by an oxygen atom or a carbonyl group;
provided that the total carbon number contained in the group of Lb4 and Lb5 is 22 or less;
Lb6 represents a single bond or a C1 to C23 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group;
Lb7 represents a single bond or a C1 to C23 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group, and a methylene group may be replaced by an oxygen atom or a carbonyl group;
provided that the total carbon number contained in the group of Lb6 and Lb7 is 23 or less, and
* represents a binding site to Y.
In formula (b1-1) to formula (b1-3), when a methylene group has been replaced by an oxygen atom or a carbonyl group, the carbon number of the saturated hydrocarbon group corresponds to the number of the carbon atom before replacement.
Examples of the divalent saturated hydrocarbon group are the same examples as the divalent saturated hydrocarbon group of Lb1.
Lb2 is preferably a single bond.
Lb3 is preferably a C1 to C4 divalent saturated hydrocarbon group.
Lb4 is preferably a C1 to C8 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom.
Lb5 is preferably a single bond or a C1 to C8 divalent saturated hydrocarbon group.
Lb6 is preferably a single bond or a C1 to C4 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom.
Lb7 is preferably a single bond or a C1 to C18 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group, and where a methylene group may be replaced by an oxygen atom or a carbonyl group.
Among these, the group represented by the formula (b1-1) or the formula (b1-3) is preferred.
Examples of the divalent group represented by the formula (b1-1) include the following groups represented by formula (b1-4) to formula (b1-8):




wherein Lb8 represents a single bond or a C1 to C22 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group;
Lb9 represents a C1 to C20 divalent saturated hydrocarbon group;
Lb10 represents a single bond or a C1 to C19 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group;
provided that the total carbon number contained in the group of Lb9 and Lb10 is 20 or less;
Lb11 represents a C1 to C21 divalent saturated hydrocarbon group;
Lb12 represents a single bond or a C1 to C20 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group;
provided that the total carbon number contained in the group of Lb11 and Lb12 is 21 or less;
Lb13 represents a C1 to C19 divalent saturated hydrocarbon group;
Lb14 represents a single bond or a C1 to C18 divalent saturated hydrocarbon group;
Lb15 represents a single bond or a C1 to C18 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group;
provided that the total carbon number contained in the group of Lb13, Lb14 and Lb15 is 19 or less;
Lb16 represents a C1 to C18 divalent saturated hydrocarbon group;
Lb17 represents a C1 to C18 divalent saturated hydrocarbon group;
Lb18 represents a single bond or a C1 to C17 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom or a hydroxy group;
provided that the total carbon number contained in the group of Lb16, Lb17 and Lb18 is 19 or less.
Lb8 is preferably a C1 to C4 divalent saturated hydrocarbon group.
Lb9 is preferably a C1 to C8 divalent saturated hydrocarbon group.
Lb10 is preferably a single bond or a C1 to C19 divalent saturated hydrocarbon group, and more preferably a single bond or a C1 to C8 divalent saturated hydrocarbon group.
Lb11 is preferably a C1 to C8 divalent saturated hydrocarbon group.
Lb12 is preferably a single bond or a C1 to C8 divalent saturated hydrocarbon group.
Lb13 is preferably a C3 to C12 divalent saturated hydrocarbon group.
Lb14 is preferably a single bond or a C1 to C6 divalent saturated hydrocarbon group.
Lb15 is preferably a single bond or a C1 to C18 divalent saturated hydrocarbon group, and more preferably a single bond or a C1 to C8 divalent saturated hydrocarbon group.
Lb16 is preferably a C1 to C12 divalent saturated hydrocarbon group.
Lb17 is preferably a C1 to C6 divalent saturated hydrocarbon group.
Lb18 is preferably a single bond or a C1 to C17 divalent saturated hydrocarbon group, and more preferably a single bond or a C1 to C4 divalent saturated hydrocarbon group.
Examples of the divalent group represented by the formula (b1-3) include the following groups represented by formula (b1-9) to formula (b1-11):




wherein Lb19 represents a single bond or a C1 to C23 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom;
Lb20 represent a single bond or a C1 to C23 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom, a hydroxy group or an acyloxy group, and a methylene group contained in an acyloxy group may be replaced by an oxygen atom or a carbonyl group, and a hydrogen atom contained in an acyloxy group may be replaced by a hydroxy group,
provided that the total carbon number contained in the group of Lb19 and Lb20 is 23 or less;
Lb21 represents a single bond or a C1 to C21 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom;
Lb22 represents a single bond or a C1 to C21 divalent saturated hydrocarbon group;
Lb23 represents a single bond or a C1 to C21 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom, a hydroxy group or an acyloxy group, and a methylene group contained in an acyloxy group may be replaced by an oxygen atom or a carbonyl group, and a hydrogen atom contained in an acyloxy group may be replaced by a hydroxy group,
provided that the total carbon number contained in the group of Lb21, Lb22 and Lb23 is 21 or less;
Lb24 represents a single bond or a C1 to C20 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom;
Lb25 represents a single bond or a C1 to C21 divalent saturated hydrocarbon group;
Lb26 represents a single bond or a C1 to C20 divalent saturated hydrocarbon group where a hydrogen atom may be replaced by a fluorine atom, a hydroxy group or an acyloxy group, and a methylene group contained in an acyloxy group may be replaced by an oxygen atom or a carbonyl group, and a hydrogen atom contained in an acyloxy group may be replaced by a hydroxy group,
provided that the total carbon number contained in the group of Lb24, Lb25 and Lb26 is 21 or less.
In formula (b1-9) to formula (b1-11), when a hydrogen atom has been replaced by an acyloxy group, the carbon number of the saturated hydrocarbon group corresponds to the number of the carbon atom, CO and O in addition to the carbon number of the saturated hydrocarbon group.
Examples of the acyloxy group include acetyloxy, propionyloxy, butyryloxy, cyclohexyl carbonyloxy and adamantyl carbonyloxy groups.
Examples of the acyloxy group having a substituent include oxoadamantyl carbonyloxy, hydroxyadamantyl carbonyloxy, oxocyclohexyl carbonyloxy and hydroxycyclohexyl carbonyloxy groups.
Examples of the group represented by the formula (b1-4) include the following ones.




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




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




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




Examples of the group represented by the formula (b1-8) include the following ones.




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




Examples of the group represented by the formula (b1-9) include the following ones.




Examples of the group represented by the formula (b1-10) include the following ones.










Examples of the group represented by the formula (b1-11) include the following ones.







Examples of the monovalent alicyclic hydrocarbon group for Y include groups represented by formula (Y1) to formula (Y11).
Examples of the monovalent alicyclic hydrocarbon group for Y in which a methylene group has been replaced by an oxygen atom, a carbonyl group or a sulfonyl group include groups represented by formula (Y12) to formula (Y27).










Among these, the alicyclic hydrocarbon group is preferably any one of groups represented by the formula (Y1) to the formula (Y20), more preferably any one of groups represented by the formula (Y11), (Y15), (Y16) or (Y20), and still more preferably group represented by the formula (Y11) or (Y15).
Examples of the substituent on methyl group of Y include a halogen atom, a hydroxyl group, a C3 to C16 monovalent alicyclic hydrocarbon group, a C6 to C18 monovalent aromatic hydrocarbon group, a glycidyloxy group and —(CH2)j2—O—CO—Rb1— in which Rb1 represents an C1 to C16 alkyl group, a C3 to C16 monovalent alicyclic hydrocarbon group, or a C6 to C18 monovalent aromatic hydrocarbon group, and j2 represents an integer of 0 to 4.
Examples of the substituent on the alicyclic group for Y include a halogen atom, a hydroxyl group, a C1 to C12 alkyl group, a hydroxy group-containing C1 to C12 alkyl group, a C3 to C16 monovalent alicyclic hydrocarbon group, a C1 to C12 alkoxy group, a C6 to C18 monovalent aromatic hydrocarbon group, a C7 to C21 aralkyl group, a C2 to C4 acyl group, a glycidyloxy group and —(CH2)j2—O—CO—Rb1—, in which Rb1 represents an C1 to C16 alkyl group, a C3 to C16 monovalent alicyclic hydrocarbon group, or a C6 to C18 monovalent aromatic hydrocarbon group, and j2 represents an integer of 0 to 4.
Examples of the hydroxy group-containing alkyl group include hydroxymethyl and hydroxyethyl groups
Examples of the alkoxyl group include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy and dodecyloxy groups.
Examples of the monovalent aromatic hydrocarbon group include an aryl group such as phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl, phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.
Examples of the aralkyl group include benzyl, phenethyl, phenylpropyl, naphthylmethyl and naphthylethyl groups.
Examples of the acyl group include acetyl, propionyl and butyryl groups.
Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of Y include the groups below. * represents a binding site to Lb1.




When Y is methyl group and Lb1 is a liner or branched C1 to C17 divalent saturated hydrocarbon group, a methylene group which is contained in the divalent saturated hydrocarbon group and is positioned at a binding site of Y preferably replaces with —O— or —CO—.
Y is preferably a C3 to C18 monovalent alicyclic hydrocarbon group which may have a substituent, more preferably an adamantyl group which may have a substituent and one or more methylene group contained in the adamantyl group may be replaced with an oxygen atom, a carbonyl group or a sulfonyl group, and still more preferably an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group.
The sulfonic acid anion in the salt represented by the formula (B1) is preferably an anions represented by formula (B1-A-1) to formula (B1-A-33), and more preferably an anions represented by formula (B1-A-1) to formula (B1-A-4), formula (B1-A-9), formula (B1-A-10), formula (B1-A-24) to formula (B1-A-33), below.
In formula (B1-A-1) to formula (B1-A-33), Ri2 to Ri7 each independently represent a C1 to C4 alkyl group, and preferably a methyl group or an ethyl group, Ri8 represent a C1 to C12 aliphatic hydrocarbon group, preferably a C1 to C4 alkyl group, a C5 to C12 monovalent alicyclic hydrocarbon group or a group formed by a combination thereof, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. L44 represents a single bond or a C1 to C4 alkanediyl group. Q1 and Q2 represent the same meaning as defined above.
Specific examples of the sulfonic acid anion in the salt represented by the formula (B1) include anions mentioned in JP2010-204646A1.
















Among these, preferred examples of the sulfonic acid anion for the salt represented by the formula (B1) include anions represented by formulae (B1a-1) to (B1a-15).










Preferred examples of the sulfonic acid anion include anions represented by the formulae (B1a-1) to (B1a-3) and (B1a-7) to (B1a-15).
Examples of the organic cation represented by Z+ include an organic onium cation such as an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation and an organic phosphonium cation. An organic sulfonium cation and an organic iodonium cation are preferred, and an arylsulfonium cation is more preferred.
Z+ of the formula (B1) is preferably represented by any of formula (b2-1) to formula (b2-4):




wherein Rb4, Rb5 and Rb6 each independently represent a C1 to C30 aliphatic hydrocarbon group, a C3 to C36 alicyclic hydrocarbon group or a C6 to C36 aromatic hydrocarbon group, a hydrogen atom contained in the aliphatic hydrocarbon group may be replaced by a hydroxy group, a C1 to C12 alkoxy group, a C3 to C12 alicyclic hydrocarbon group or a C6 to C18 aromatic hydrocarbon group, a hydrogen atom contained in the alicyclic hydrocarbon group may be replaced by a halogen atom, a C1 to C18 aliphatic hydrocarbon group, a C2 to C4 acyl group or a glycidyloxy group, a hydrogen atom contained in the aromatic hydrocarbon group may be replaced by a halogen atom, a hydroxy group or a C1 to C12 alkoxy group, or Rb4 and Rb5 may be bonded together with a sulfur atom bonded thereto to form a sulfur-containing ring, a methylene group contained in the ring may be replaced by an oxygen atom, a —SO— or a carbonyl group;
Rb7 and Rb8 in each occurrence independently represent a hydroxy group, a C1 to C12 aliphatic hydrocarbon group or a C1 to C12 alkoxy group,
m2 and n2 independently represent an integer of 0 to 5;
Rb9 and Rb10 each independently represent a C1 to C36 aliphatic hydrocarbon group or a C3 to C36 alicyclic hydrocarbon group, or Rb9 and Rb10 may be bonded together with a sulfur atom bonded thereto to form a sulfur-containing ring, and a methylene group contained in the ring may be replaced by an oxygen atom, a —SO— or a carbonyl group;
Rb11 represents a hydrogen atom, a C1 to C36 aliphatic hydrocarbon group, a C3 to C36 alicyclic hydrocarbon group or a C6 to C18 aromatic hydrocarbon group;
Rb12 represents a C1 to C12 aliphatic hydrocarbon group, a C3 to C18 alicyclic hydrocarbon group and a C6 to C18 aromatic hydrocarbon group, a hydrogen atom contained in the aliphatic hydrocarbon group may be replaced by a C6 to C18 aromatic hydrocarbon group, and a hydrogen atom contained in the aromatic hydrocarbon group may be replaced by a C1 to C12 alkoxy group or a C1 to C12 alkyl carbonyloxy group;
Rb11 and Rb12 may be bonded together with —CH—CO— bonded thereto to form a ring, and a methylene group contained in the ring may be replaced by an oxygen atom, a —SO— or a carbonyl group;
Rb13, Rb14, Rb15, Rb16, Rb17 and Rb18 in each occurrence independently represent a hydroxy group, a C1 to C12 aliphatic hydrocarbon group or a C1 to C12 alkoxy group;
Lb31 represents —S— or —O—;
o2, p2, s2 and t2 independently represent an integer of 0 to 5;
q2 or r2 independently represent an integer of 0 to 4; and
u2 represents an integer of 0 or 1.
Examples of the aliphatic group include an alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl and 2-ethylhexyl groups. Among these, the aliphatic hydrocarbon group of Rb9 to Rb12 is preferably a C1 to C12 aliphatic hydrocarbon group.
Examples of the alicyclic hydrocarbon group include monocyclic groups such as a cycloalkyl group, i.e., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl groups; and polycyclic groups such as decahydronaphtyl, adamantyl and norbornyl groups as well as the following groups. * represents a binding site.




Among these, the alicyclic hydrocarbon group of Rb9 to Rb12 is preferably a C3 to C18 alicyclic hydrocarbon group, and more preferably a C4 to C12 alicyclic hydrocarbon group.
Examples of the alicyclic hydrocarbon group where a hydrogen atom may be replaced by an aliphatic hydrocarbon group include methylcyclohexyl, dimethylcyclohexyl, 2-alkyladamantane-2-yl, methylnorbornyl and isobornyl groups. In the alicyclic hydrocarbon group where a hydrogen atom may be replaced by an aliphatic hydrocarbon group, the total carbon number of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.
Examples of the aromatic hydrocarbon group include an aryl group such as phenyl, tolyl, xylyl, cumenyl, mesityl, p-ethylphenyl, p-tert-butylphenyl, p-cyclohexylphenyl, p-adamantylphenyl, biphenyl, naphthyl, phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.
When the aromatic hydrocarbon includes an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, a C1 to C18 aliphatic hydrocarbon group or a C3 to C18 alicyclic hydrocarbon group is preferred.
Examples of the aromatic hydrocarbon group where a hydrogen atom may be replaced by an alkoxy group include a p-methoxyphenyl group.
Examples of the aliphatic hydrocarbon group where a hydrogen atom may be replaced by an aromatic hydrocarbon group include an aralkyl group such as benzyl, phenethyl phenylpropyl, trityl, naphthylmethyl and naphthylethyl groups.
Examples of the alkoxy group include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy and dodecyloxy groups.
Examples of the acyl group include acetyl, propionyl and butyryl groups.
Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the alkylcarbonyloxy group include methylcarbonyloxy, ethylcarbonyloxy, n-propylcarbonyloxy, isopropylcarbonyloxy, n-butylcarbonyloxy, sec-butylcarbonyloxy, tert-butyl carbonyloxy, pentylcarbonyloxy, hexylcarbonyloxy, octylcarbonyloxy and 2-ethylhexylcarobonyloxy groups.
The sulfur atom-containing ring which is formed by Rb4 and Rb5 may be a monocyclic or polycyclic group, which may be an aromatic or non-aromatic group, and which may be a saturated or unsaturated group. The ring is preferably a ring having 3 to 18 carbon atoms, and more preferably a ring having 4 to 18 carbon atoms. Examples of the sulfur atom-containing ring include a 3- to 12-membered ring, preferably a 3- to 7-membered ring, examples thereof include the following rings.




The sulfur atom-containing ring which is formed by Rb9 and Rb10 may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. The ring may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples of the ring include thiolane-1-ium ring (tetrahydrothiophenium ring), thian-1-ium ring and 1,4-oxathian-4-ium ring.
Examples of the ring formed by Rb11 and Rb12 may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. The ring may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples of the ring include oxocycloheptane ring, oxocyclohexane ring, oxonorbornane ring and oxoadamantane ring.
Among the cations represented by the formula (b2-1) to the formula (b2-4), the cation represented by the formula (b2-1) is preferred.
Examples of the cation (b2-1) include the following ones.



















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




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




Examples of the cation (b2-4) include the following ones.







The acid generator (B1) is generally a compound which consists of the above sulfonate anion with an organic cation. The above sulfonic acid anion and the organic cation may optionally be combined. Preferred combination is a combination of any of the anion represented by the formula (B1a-1) to the formula (B1a-3), the formula (B1a-7) to the formula (B1a-15) and the cation represented by the formula (b2-1) or the formula (b2-3).
Preferred acid generators (B1) are represented by formula (B1-1) to formula (B1-30). Among these, formulae (B1-1), (B1-2), (B1-3), (B1-5), (B1-6), (B1-7), (B1-11), (B1-12), (B1-13), (B1-14), (B1-17), (B1-20), (B1-21), (B1-23), (B1-24), (B1-25), (B1-26) and (B1-29) which contain arylsulfonium cation are preferred.

























The proportion of the acid generator (B1) is preferably 30% by mass or more, and 100% by mass or less, more preferably 50% by mass or more, and 100% by mass or less, and still more preferably substantially 100% by weight with respect to 100% by mass of total acid generator (B).
In the resist composition of the disclosure, the proportion of the acid generator (B) is preferably 1 parts by mass or more and more preferably 3 parts by mass or more, and preferably 30 parts by mass or less and more preferably 25 parts by mass or less with respect to 100 parts by mass of the resin (A1).
<Solvent (E)>
The proportion of a solvent (E) is generally 90% by mass or more, preferably 92% by mass or more, and more preferably 94% by mass or more, and also preferably 99% by mass or less, and more preferably 99.9% by mass or less. The proportion of the solvent (E) can be measured with a known analytical method such as liquid chromatography and gas chromatography.
Examples of the solvent (E) include glycol ether esters such as ethylcellosolve acetate, methylcellosolve acetate and propyleneglycolmonomethylether acetate; glycol ethers such as propyleneglycolmonomethylether; esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; and cyclic esters such as γ-butyrolactone. These solvents may be used as a single solvent or as a mixture of two or more solvents.
<Quencher (C)>
The resist composition of the disclosure may further contain a quencher such as a basic nitrogen-containing organic compound and a salt which generates an acid weaker in acidity than an acid generated from the acid generator.
Examples of the quencher include a basic nitrogen-containing organic compound and a salt which generates an acid weaker in acidity than an acid generated from the acid generator (B).
<Basic Nitrogen-containing Organic Compound>
Examples of the basic nitrogen-containing organic compound include an amine and ammonium salts.
Examples of the amine include an aliphatic amine and an aromatic amine. Examples of the aliphatic amine include a primary amine, secondary amine and tertiary amine. Specific examples of the amine include 1-naphtylamine, 2-naphtylamine, 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, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylene diamine, tetramethylene diamine, hexamethylene diamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, 2,2′-methylenebisaniline, 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 and bipyridine. Among these, diisopropylaniline is preferred, particularly 2,6-diisopropylaniline is more preferred.
Specific examples of the ammonium salt include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethyl ammonium hydroxide, 3-(trifluoromethyl)phenyltrimethylammonium hydroxide, tetra-n-butyl ammonium salicylate and choline.
<Weak Acid Salt>
The salt generating an acid which is lower in acidity than an acid generated from the acid generator (B) is sometimes referred to as “weak acid salt”. The “acidity” can be represented by acid dissociation constant, pKa, of an acid generated from a weak acid salt. Examples of the weak acid salt include a salt generating an acid of pKa represents generally more than −3, preferably −1 to 7, and more preferably 0 to 5.
Specific examples of the weak acid salt include the following salts, the salt of formula (D), and salts as disclosed in JP2012-229206A1, JP2012-6908A1, JP2012-72109A1, JP2011-39502A1 and JP2011-191745A1.










A weakly acidic inner salt (D) is a compound represented by the formula (D).




In the formula (D), RD1 and RD2 in each occurrence independently represent a C1 to C12 hydrocarbon group, a C1 to C6 alkoxyl group, a C2 to C7 acyl group, a C2 to C7 acyloxy group, a C2 to C7 alkoxycarbonyl group, a nitro group or a halogen atom;
m′ and n′ each independently represent an integer of 0 to 4.
Examples of the hydrocarbon group of RD1 and RD2 include any of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group and a combination thereof.
Examples of the aliphatic hydrocarbon group include an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl and nonyl groups.
The alicyclic hydrocarbon group is any one of monocyclic or polycyclic hydrocarbon group, and saturated or unsaturated hydrocarbon group. Examples thereof include a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclononyl and cyclododecyl groups; adamantyl and norbornyl groups.
Examples of the aromatic hydrocarbon group include an aryl group such as phenyl, 1-naphthyl, 2-naphthyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-propylphenyl, 4-isopropylphenyl, 4-butylphenyl, 4-tert-butylphenyl, 4-hexylphenyl, 4-cyclohexylphenyl, anthryl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl, phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.
Examples of the combination thereof include an alkyl-cycloalkyl, a cycloalkyl-alkyl, aralkyl (e.g., phenylmethyl, 1-phenylethyl, 2-phenylethyl, 1-phenyl-1-propyl, 1-phenyl-2-propyl, 2-phenyl-2-propyl, 3-phenyl-1-propyl, 4-phenyl-1-butyl, 5-phenyl-1-pentyl and 6-phenyl-1-hexyl groups) groups.
Examples of the alkoxyl group include methoxy and ethoxy groups.
Examples of the acyl group include acetyl, propanonyl, benzoyl and cyclohexanecarbonyl groups.
Examples of the acyloxy group include a group in which oxy group (—O—) bonds to an acyl group.
Examples of the alkoxycarbonyl group include a group in which the carbonyl group (—CO—) bonds to the alkoxy group.
Example of the halogen atom is a chlorine atom, a fluorine atom and bromine atom.
In the formula (D), RD1 and RD2 in each occurrence independently preferably represent a C1 to C8 alkyl group, a C3 to C10 cycloalkyl group, a C1 to C6 alkoxyl group, a C2 to C4 acyl group, a C2 to C4 acyloxy group, a C2 to C4 alkoxycarbonyl group, a nitro group or a halogen atom.
m′ and n′ independently preferably represent an integer of 0 to 3, more preferably an integer of 0 to 2, and more preferably 0.
Specific examples of the salt of the formula (D) include compounds below.







The salt of the formula (D) can be produced by a method described in “Tetrahedron Vol. 45, No. 19, p 6281-6296”. Also, commercially available compounds can be used as the salt of the formula (D).
In the resist composition of the disclosure, the proportion of the quencher (C) is preferably 0.01% by mass to 5% by mass, more preferably 0.01% by mass to 4% by mass, and still more preferably 0.01% by mass to 3% by mass with respect to total solid components of the resist composition.
<Other Ingredient>
The resist composition can further contain other ingredient (which is sometimes referred to as “other ingredient (F)”). Examples of the other ingredient (F) include various additives such as sensitizers, dissolution inhibitors, surfactants, stabilizers, and dyes, as needed.
<Preparing the Resist Composition>
The present resist composition can be prepared by mixing the resins (X) and (A), the acid generator (B), the quencher (C), the solvent (E) and the other ingredient (F), as needed. There is no particular limitation on the order of mixing. The mixing may be performed in an arbitrary order. The temperature of mixing may be adjusted to an appropriate temperature within the range of 10 to 40° C., depending on the kinds of the resin and solubility in the solvent (E) of the resin. The time of mixing may be adjusted to an appropriate time within the range of 0.5 to 24 hours, depending on the mixing temperature. There is no particular limitation to the tool for mixing. An agitation mixing may be used.
After mixing the above ingredients, the present resist compositions can be prepared by filtering the mixture through a filter having about 0.003 to 0.2 μm pore diameter.
<Method for Producing Resist Pattern>
The method for producing a resist pattern of the disclosure includes the steps of:
(1) applying the resist composition of the disclosure onto a substrate;
(2) drying the applied composition to form a composition layer;
(3) exposing the composition layer;
(4) heating the exposed composition layer, and
(5) developing the heated composition layer.
Applying the resist composition onto the substrate can generally be carried out through the use of a resist application device, such as a spin coater known in the field of semiconductor microfabrication technique. Examples of the substrate include inorganic substrates such as silicon wafer. The substrate may be washed, and an organic antireflection film may be formed on the substrate by use of a commercially available antireflection composition, before the application of the resist composition.
The solvent evaporates from the resist composition and a composition layer with the solvent removed is formed. Drying the applied composition layer, for example, can be carried out using a heating device such as a hotplate (so-called “prebake”), a decompression device, or a combination thereof. The temperature is preferably within the range of 50 to 200° C. The time for heating is preferably 10 to 180 seconds. The pressure is preferably within the range of 1 to 1.0×105 Pa.
The obtained composition layer is generally exposed using an exposure apparatus or a liquid immersion exposure apparatus. The exposure is generally carried out using with various types of exposure light source, such as irradiation with ultraviolet lasers, i.e., KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength: 193 nm), F2 excimer laser (wavelength: 157 nm), irradiation with harmonic laser light of far-ultraviolet or vacuum ultra violet wavelength-converted laser light from a solid-state laser source (YAG or semiconductor laser or the like), or irradiation with electron beam or EUV or the like. In the specification, such exposure to radiation is sometimes referred to be collectively called as exposure. The exposure is generally carried out through a mask that corresponds to the desired pattern. When electron beam is used as the exposure light source, direct writing without using a mask can be carried out.
After exposure, the composition layer is subjected to a heat treatment (so-called “post-exposure bake”) to promote the deprotection reaction. The heat treatment can be carried out using a heating device such as a hotplate. The heating temperature is generally in the range of 50 to 200° C., preferably in the range of 70 to 150° C.
The developing of the baked composition film is usually carried out with a developer using a development apparatus. Developing can be conducted in the manner of dipping method, paddle method, spray method and dynamic dispensing method. Temperature for developing is generally 5 to 60° C. The time for developing is preferably 5 to 300 seconds.
The photoresist pattern obtained from the photoresist composition may be a positive one or a negative one by selecting suitable developer.
The development for obtaining a positive photoresist pattern is usually carried out with an alkaline developer. The alkaline developer to be used may be any one of various alkaline aqueous solution used in the art. Generally, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl)trimethylammonium hydroxide (commonly known as “choline”) is often used. The surfactant may be contained in the alkaline developer.
After development, the resist pattern formed is preferably washed with ultrapure water, and the residual water remained on the resist film or on the substrate is preferably removed therefrom.
The development for obtaining a negative photoresist pattern is usually carried out with a developer containing an organic solvent. The organic solvent to be used may be any one of various organic solvents used in the art, examples of which include ketone solvents such as 2-hexanone, 2-heptanone; glycol ether ester solvents such as propyleneglycolmonomethylether acetate; ester solvents such as the butyl acetate; glycol ether solvents such as the propyleneglycolmonomethylether; amide solvents such as N,N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
In the developer containing an organic solvent, the amount of organic solvents is preferably 90% by mass to 100% by mass, more preferably 95% by mass to 100% by mass of the developer. The developer still more preferably consists essentially of organic solvents.
Among these, the developer containing an organic solvent preferably contains butyl acetate and/or 2-heptanone. In the developer containing an organic solvent, the total amount of butyl acetate and 2-heptanone is preferably 50% by mass to 100% by mass of the developer, more preferably 90% by mass to 100% by mass of the developer. The developer still more preferably consists essentially of butyl acetate and/or 2-heptanone.
Developers containing an organic solvent may contain a surfactant. Also, the developer containing an organic solvent may include a little water.
The developing with a developer containing an organic solvent can be finished by replacing the developer by another solvent.
After development, the photoresist pattern formed is preferably washed with a rinse agent. Such rinse agent is not unlimited provided that it does not detract a photoresist pattern. Examples of the agent include solvents which contain organic solvents other than the above-mentioned developers, such as alcohol agents or ester agents.
After washing, the residual rinse agent remained on the substrate or photoresist film is preferably removed therefrom.
<Application>
The resist composition of the disclosure is useful for excimer laser lithography such as ArF, KrF, electron beam (EB) exposure lithography or extreme-ultraviolet (EUV) exposure lithography, and is more useful for ArF excimer laser exposure lithography.
The resist composition of the disclosure can be used in semiconductor microfabrication.
EXAMPLES
The disclosure will be described more specifically by way of examples, which are not construed to limit the scope of the disclosure.
All percentages and parts expressing the content or amounts used in the Examples and Comparative Examples are based on mass, unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography.
Column: TSK gel Multipore HXL-M×3+guardcolumn (Tosoh Co. Ltd.)
Eluant: tetrahydrofuran
Flow rate: 1.0 mL/min
Detecting device: RI detector
Column temperature: 40° C.
Injection amount: 100 μL
Standard material for calculating molecular weight: standard polystyrene (Tosoh Co. ltd.)
Structures of compounds were determined by mass spectrometry (Liquid Chromatography: 1100 Type, manufactured by AGILENT TECHNOLOGIES LTD., Mass Spectrometry: LC/MSD Type, manufactured by AGILENT TECHNOLOGIES LTD.). The value of the peak in the mass spectrometry is referred to as “MASS”.
Example 1
Synthesis of the Compound Represented by Formula (I-4)




Into a reactor, 15 parts of the compound represented by the formula (I-4-a), 75 parts of chloroform, 9.51 parts of dimethylaminopyridine, 12.26 parts of the compound represented by the formula (I-4-b) and 15.85 parts of the compound represented by the formula (I-4-c) were charged, then, stirred at 23° C. for 18 hours. To the obtained reaction mixture, 130 parts of n-heptane and 57 parts of 5% hydrochloric acid were added, and stirred at 23° C. for 30 minute. The mixture was left still, followed by separating an organic layer. The washing step with water was conducted twice. To the obtained organic layer, 65 parts of ion-exchanged water were added and stirred at 23° C. for 30 minutes. Then, the mixture was left still, followed by separating an organic layer to wash with water. To the obtained organic layer, 20 parts of saturated aqueous solution of sodium hydrogen carbonate was added, stirred at 23° C. for 30 minutes, and left still, followed by separating an organic layer to wash with water. To the obtained organic layer, 65 parts of ion-exchanged water was added, stirred at 23° C. for 30 minutes, and left still, followed by separating an organic layer to wash with water. The washing step with water was conducted five times. The washed organic layer was concentrated and purified with column chromatography [silica gel 60N, spherical shape, neutral, 100-210 μm, eluent solvent: mixture of n-heptane and ethyl acetate (weight ratio 20/1), manufactured by Kanto Chem. Ltd.] to obtain 16.19 parts of the compound represented by formula (I-4).
MS (mass spectrography): 458.2 (molecular ion peak)
Example 2
Synthesis of the Compound Represented by Formula (I-5)




Into a reactor, 15 parts of the compound represented by the formula (I-5-a), 75 parts of chloroform, 9.51 parts of dimethylaminopyridine, 10.95 parts of the compound represented by the formula (I-5-b) and 15.85 parts of the compound represented by the formula (I-5-c) were charged, then, stirred at 23° C. for 18 hours. To the obtained reaction mixture, 130 parts of n-heptane and 57 parts of 5% hydrochloric acid were added, and stirred at 23° C. for 30 minutes. Then, the mixture was left still, followed by separating an organic layer. The washing step with water was conducted twice. To the obtained organic layer, 65 parts of ion-exchanged water were added and stirred at 23° C. for 30 minutes. Then, the mixture was left still, followed by separating an organic layer to wash with water. To the obtained organic layer, 20 parts of saturated aqueous solution of sodium hydrogen carbonate was added and stirred at 23° C. for 30 minutes, and left still, followed by separating an organic layer to wash with water. To the obtained organic layer, 65 parts of ion-exchanged water was added and stirred at 23° C. for 30 minutes, and left still, followed by separating an organic layer to wash with water. The washing step with water was conducted five times. The washed organic layer was concentrated and purified with column chromatography [silica gel 60N, spherical shape, neutral, 100-210 μm, eluent solvent: mixture of n-heptane and ethyl acetate (weight ratio 20/1), manufactured by Kanto Chem. Ltd.] to obtain 16.68 parts of the compound represented by formula (I-5).
MS (mass spectrography): 440.2 (molecular ion peak)
Example 3
Synthesis of a Compound Represented by Formula (I-3)




Into a reactor, 15 parts of the compound represented by the formula (I-3-a), 75 parts of chloroform, 9.51 parts of dimethylaminopyridine, 14.60 parts of the compound represented by the formula (I-3-b) and 15.85 parts of the compound represented by the formula (I-3-c) were charged, then, stirred at 23° C. for 18 hours. To the obtained reaction mixture, 130 parts of n-heptane and 57 parts of 5% hydrochloric acid were added, stirred at 23° C. for 30 minutes. Then, the mixture was left still, followed by separating an organic layer. The washing step with water was conducted twice. To the obtained organic layer, 65 parts of ion-exchanged water were added and stirred at 23° C. for 30 minutes. Then, the mixture was left still, followed by separating an organic layer to wash with water. To the obtained organic layer, 20 parts of saturated aqueous solution of sodium hydrogen carbonate was added, stirred at 23° C. for 30 minutes, and left still, followed by separating an organic layer to wash with water. To the obtained organic layer, 65 parts of ion-exchanged water was added, stirred at 23° C. for 30 minutes, and left still, followed by separating an organic layer to wash with water. The washing step with water was conducted five times. The washed organic layer was concentrated and purified with column chromatography [silica gel 60N spherical shape, neutral, 100-210 μm, eluent solvent: mixture of n-heptane and ethyl acetate (weight ratio 20/1), manufactured by Kanto Chem. Ltd.] to obtain 16.84 parts of the compound represented by formula (I-3).
MS (mass spectrography): 490.2 (molecular ion peak)
Synthesis Example 1
Synthesis of the Salt Represented by Formula (B1-5)




Into a reactor, 50.49 parts of a salt represented by the formula (B1-5-a) and 252.44 parts of chloroform were charged and stirred at 23° C. for 30 minutes. Then 16.27 parts of a compound represented by the formula (B1-5-b) were dropped thereinto and the obtained mixture was stirred at 23° C. for one hour to obtain a solution containing a salt represented by the formula (B1-5-c). To the obtained solution, 48.80 parts of a salt represented by the formula (B1-5-d) and 84.15 parts of ion-exchanged water were added and the obtained mixture was stirred at 23° C. for 12 hours. From the obtained solution which had two layers, a chloroform layer was collected and then 84.15 parts of ion-exchanged water were added thereto for washing. These steps were conducted five times. To the washed chloroform layer, 3.88 parts of active carbon was added and the obtained mixture was stirred, followed by filtrating. The collected filtrate was concentrated and then 125.87 parts of acetonitrile were added thereto and the obtained mixture was stirred, followed by being concentrated. 20.62 parts of acetonitrile and 309.30 parts of tert-butyl methyl ether were added to the obtained residues, followed by being stirred at 23° C. for about 30 minutes. Then a supernatant was removed therefrom, and the residues were concentrated. To the concentrated residues, 200 parts of n-heptane were added and the obtained mixture was stirred at 23° C. for about 30 minutes, followed by being filtrated to obtain 61.54 parts of the salt represented by the formula (B1-5).
MASS(ESI(+)Spectrum): M+ 375.2
MASS(ESI(−)Spectrum): M− 339.1
Synthesis Example 2
Synthesis of the Salt Represented by Formula (B1-21)




The compound represented by the formula (B1-21-b) was produced according to a method recited in JP2008-209917A1.
Into a reactor, 30.00 parts of the compound represented by the formula (B1-21-b) and 35.50 parts of a salt 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 about 15 hours. From the obtained solution which had two layers, a chloroform layer was collected and then 30 parts of ion-exchanged water was added thereto for washing. These steps were conducted five times. Then the washed layer was concentrated, and then, 100 parts of tert-butyl methyl ether was added to the obtained residues and the obtained mixture was stirred at 23° C. for about 30 minutes. The resulting mixture was filtrated to obtain 48.57 parts of the salt represented by the formula (B1-21-c).




Into a reactor, 20.00 parts of salt represented by the formula (B1-21-c), 2.84 parts of 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 resulting mixture, 0.21 parts of copper (II) dibenzoate was added and the obtained mixture was stirred at 100° C. for 1 hour. The reaction mixture was concentrated, and then, 200 parts of chloroform and 50 parts of ion-exchanged water were added to the obtained residues and the obtained mixture was stirred at 23° C. for 30 minutes, followed by separating an organic layer. 50 parts of ion-exchanged water was added to the obtained organic layer, and the obtained mixture was stirred at 23° C. for 30 minutes, followed by separating an organic layer. The washing step with water was conducted five times. The obtained organic layer was concentrated, and then the obtained residues were dissolved in 53.51 parts of acetonitrile. Then the mixture was concentrated, and 113.05 parts of tert-butyl methyl ether was added thereto and the obtained mixture was stirred, followed by filtrating it to obtain 10.47 parts of the salt represented by the formula (B1-21).
MASS(ESI(+)Spectrum): M+ 237.1
MASS(ESI(−)Spectrum): M− 339.1
Synthesis Example 3
Synthesis of the Salt Represented by Formula (B1-22)




Into a reactor, 11.26 parts of the salt represented by the formula (B1-21-a), 10 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 stirred at 23° C. for about 15 hours. From the obtained solution which had two layers, a chloroform layer was collected and then 15 parts of ion-exchanged water were added thereto for washing. These steps were conducted five times. Then the washed layer was concentrated, and then 50 parts of tert-butyl methyl ether was added to the obtained residues, and the obtained mixture was stirred at 23° C. for about 30 minutes. The resulting mixture was filtrated to obtain 11.75 parts of the salt represented by the formula (B1-22-c).




Into a reactor, 11.71 parts of a salt represented by the formula (B1-22-c), 1.70 parts of a compound represented by the formula (B1-21-d) and 46.84 parts of monochlorobenzene were charged and stirred at 23° C. for 30 minutes. To the resulting mixture, 0.12 parts of copper (II) dibenzoate was added and the obtained mixture was stirred at 100° C. for 30 minutes. The reaction mixture was concentrated, and then 50 parts of chloroform and 12.50 parts of ion-exchanged water were added to the obtained residues, and the obtained mixture was stirred at 23° C. for 30 minutes, followed by separating an organic layer. 12.50 parts of ion-exchanged water was added to the obtained organic layer and the obtained mixture was stirred at 23° C. for 30 minutes, followed by separating an organic layer to wash with water. The washing step with water was conducted eight times. Then the obtained organic layer was concentrated, and 50 parts of tert-butyl methyl ether were added thereto and the obtained mixture was stirred, followed by filtrating it to obtain 6.84 parts of the salt represented by the formula (B1-22).
MASS(ESI(+)Spectrum): M+ 237.1
MASS(ESI(−)Spectrum): M− 323.0
Synthesis Examples of Resins
The monomers used for Synthesis Examples of the resins are shown below. These monomers are referred to as “monomer (X)” where “(X)” is the symbol of the formula representing the structure of each monomer.







Example 4
Synthesis of Resin X1
Into monomer (I-4), propyleneglycolmonomethylether acetate was added in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 0.7% by mole and 2.1% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 75° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. Thus obtained resin was poured into methanol to precipitate the resin. The obtained resin was filtrated to obtain the polymer having a weight average molecular weight of about 13000 in 80% yield. This resin, which had the structural units of the following formula, was referred to as Resin X1.




Example 5
Synthesis of Resin X2
Monomer (I-4) and monomer (a5-1-1) were mixed together with the mole ratio of monomer (I-4) and monomer (a5-1-1)=50:50, and propyleneglycolmonomethylether acetate was added thereto in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 0.7% by mole and 2.1% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 75° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. Thus obtained resin was poured into methanol to precipitate the resin. The obtained resin was filtrated to obtain the copolymer having a weight average molecular weight of about 13000 in 86% yield. This resin, which had the structural units of the following formulae, was referred to as Resin X2.




Example 6
Synthesis of Resin X3
Monomer (I-4) and monomer (a5-1-1) were mixed together with the mole ratio of monomer (I-4) and monomer (a5-1-1)=50:50, and propyleneglycolmonomethylether acetate was added thereto in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 1% by mole and 3% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 75° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. Thus obtained resin was poured into methanol to precipitate the resin. The obtained resin was filtrated to obtain the copolymer having a weight average molecular weight of about 8400 in 78% yield. This resin, which had the structural units of the following formulae, was referred to as Resin X3.




Example 7
Synthesis of X4
Monomer (I-4), monomer (a4-0-12) and monomer (a5-1-1) were mixed together with the mole ratio of monomer (I-4), (a4-0-12) and monomer (a5-1-1)=50:25:25, and propyleneglycolmonomethylether acetate was added thereto in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 1% by mole and 3% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 75° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. Thus obtained resin was poured into methanol to precipitate the resin. The obtained resin was filtrated to obtain the copolymer having a weight average molecular weight of about 7900 in 72% yield. This resin, which had the structural units of the following formulae, was referred to as Resin X4.




Example 8
Synthesis of Resin X5
Monomer (I-3) and monomer (a5-1-1) were mixed together with the mole ratio of monomer (I-3) and monomer (a5-1-1)=50:50, and propyleneglycolmonomethylether acetate was added thereto in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 1% by mole and 3% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 75° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. Thus obtained resin was poured into methanol to precipitate the resin. The obtained resin was filtrated to obtain the copolymer having a weight average molecular weight of about 8600 in 70% yield. This resin, which had the structural units of the following formulae, was referred to as Resin X5.




Example 9
Synthesis of Resin X6
Monomer (I-5) and monomer (a5-1-1) were mixed together with the mole ratio of monomer (I-5) and monomer (a5-1-1)=50:50, and propyleneglycolmonomethylether acetate was added thereto in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 1% by mole and 3% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 75° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. Thus obtained resin was poured into methanol to precipitate the resin. The obtained resin was filtrated to obtain the copolymer having a weight average molecular weight of about 8000 in 75% yield. This resin, which had the structural units of the following formulae, was referred to as Resin X6.




Synthesis Example 4
Synthesis of Resin A1
Monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3) and monomer (a3-4-2) were mixed together with a mole ratio of monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3) and monomer (a3-4-2)=45:14:2.5:38.5, and propyleneglycolmonomethylether acetate was added thereto in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 1% by mole and 3% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 73° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. The obtained resin was dissolved in another propyleneglycolmonomethylether acetate to obtain a solution, and the solution was poured into a mixture of methanol and water to precipitate the resin. The obtained resin was filtrated. These operations were conducted twice to obtain the copolymer having a weight average molecular weight of about 7600 in 68% yield. This resin, which had the structural units of the following formulae, was referred to as Resin A1.




Synthesis Example 5
Synthesis of Resin A2
Monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-1) and monomer (a3-4-2) were mixed together with a mole ratio of monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-1) and monomer (a3-4-2)=45:14:2.5:38.5, and propyleneglycolmonomethylether acetate was added thereto in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 1% by mole and 3% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 73° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. The obtained resin was dissolved in another propyleneglycolmonomethylether acetate to obtain a solution, and the solution was poured into a mixture of methanol and water to precipitate the resin. The obtained resin was filtrated. These operations were conducted twice to obtain the copolymer having a weight average molecular weight of about 7900 in 70% yield. This resin, which had the structural units of the following formulae, was referred to as Resin A2.




Synthesis Example 6
Synthesis of Resin Xx1
Into monomer (IX), propyleneglycolmonomethylether acetate was added in the amount equal to 1.5 times by mass of the total amount of monomers to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the solution in the amounts of 0.75% by mole and 2.25% by mole respectively with respect to the total amount of monomers, and the resultant mixture was heated for about 5 hours at 75° C. Then, the obtained reaction mixture was poured into a large amount of a mixture of methanol and water to precipitate a resin. The obtained resin was filtrated. Thus obtained resin was poured into methanol to precipitate the resin. The obtained resin was filtrated to obtain Resin Xx1 having a weight average molecular weight of about 10000, in 68% yield. This resin, which had the structural units of the following formula, was referred to as Resin Xx1.




Examples 10 to 18 and Comparative Example 1
(Preparing Resist Compositions)
Resist compositions were prepared by mixing and dissolving each of the components shown in Table 1, and then filtrating through a fluororesin filter having 0.2 μm pore diameter. The obtained resist compositions were stored for 3 weeks at 30° C. Then, the properties of the resist compositions were evaluated.











TABLE 1








Weakly Acidic




Resin
Acid Generator
Inner Salt
PB/PEB


Resist Comp.
(parts)
(B) (parts)
(D) (parts)
(° C./° C.)







Composition 1
X1/A1 =
B1-21/B1-22 =
D1 = 0.28
90/85



0.7/10
0.9/0.4


Composition 2
X2/A1 =
B1-21/B1-22 =
D1 = 0.28
90/85



0.7/10
0.9/0.4


Composition 3
X1/A1 =
B1-5/B1-22 =
D1 = 0.28
90/85



0.7/10
0.4/0.4


Composition 4
X2/A2 =
B1-21/B1-22 =
D1 = 0.28
90/85



0.7/10
0.9/0.4


Composition 5
X2/A2 =
B1-21/B1-22 =
D1 = 0.28
90/85



0.4/10
0.9/0.4


Composition 6
X3/A2 =
B1-21/B1-22 =
D1 = 0.28
90/85



0.4/10
0.9/0.4


Composition 7
X4/A2 =
B1-21/B1-22 =
D1 = 0.28
90/85



0.4/10
0.9/0.4


Composition 8
X5/A2 =
B1-21/B1-22 =
D1 = 0.28
90/85



0.4/10
0.9/0.4


Composition 9
X6/A2 =
B1-21/B1-22 =
D1 = 0.28
90/85



0.4/10
0.9/0.4


Comparative
Xx1/A1 =
B1-21/B1-22 =
D1 = 0.28
90/85


Comp. 1
0.7/10
0.9/0.4









<Resin>

A1, A2, X1 to X6, Xx1: Resins A1, A2, X1 to X6, Xx1 respectively, prepared by the method as described above
<Acid Generator (B)>
B1-5: Salt represented by the formula (B1-5)
B1-21: Salt represented by the formula (B1-21)
B1-22: Salt represented by the formula (B1-22)
<Weakly Acidic Inner Salt (D)>
D1: Compound as follow, a product of Tokyo Chemical Industry Co., LTD




<Solvent for Resist Compositions>

















Propyleneglycolmonomethylether acetate
265 parts 



Propyleneglycolmonomethyl ether
20 parts



2-Heptanone
20 parts



γ-butyrolactone
3.5 parts 










<Evaluation of Resist Compositions: Negative Resist Patterns>

A composition for an organic antireflective film (“ARC-29”, by Nissan Chemical Co. Ltd.) was applied onto 12-inch silicon wafer and baked for 60 seconds at 205° C. to form a 78 nm thick organic antireflective film.
One of the resist compositions was then applied thereon by spin coating in such a manner that the thickness of the composition layer after drying (pre-baking) became 100 nm.
The obtained wafer was then pre-baked for 60 sec on a direct hot plate at the temperature given in the “PB” column in Table 1.
On the wafers on which the composition layer had thus been formed, the film was then exposed through a mask for forming trench patterns (pitch 120 nm/trench width 40 nm) with changing exposure quantity stepwise, using an ArF excimer laser stepper for liquid-immersion lithography (“XT:1900Gi” by ASML Ltd.: NA=1.35, Annular σout=0.85 σin=0.65 XY-pol.). Ultrapure water was used as medium for liquid-immersion.
After the exposure, post-exposure baking was carried out for 60 seconds at the temperature given in the “PEB” column in Table 1.
Then, development was carried out with butyl acetate (a product of Tokyo Chemical Industry Co., LTD) at 23° C. for 20 seconds in the manner of dynamic dispensing method to obtain negative resist patterns.
Effective sensitivity was represented as the exposure quantity at which the resist pattern with 40 nm trench width was obtained.
(Evaluation of Defects)
The above resist compositions were applied on each of the 12-inch-silicon wafers [circular wafers, diameter: 12 inch] by spin coating so that the thickness of the resulting film became 150 nm after drying.
The obtained wafers were then pre-baked for 60 seconds on a direct hot plate at the temperatures given in the “PB” column in Table 1 to obtain a composition layer.
The thus obtained wafers with the produced composition layers are rinsed with water for 60 seconds using a developing apparatus (ACT-12, Tokyo electron Co. Ltd.).
Thereafter, the number of defects was counted using a defect inspection apparatus (KLA-2360, KLA-Tencor Co. Ltd.)
Table 2 illustrates the results thereof.
(Focus Margin (DOF) Evaluation)
Negative resist patterns were produced in the same manner as described above, except that the exposure was conducted with changing the distance from the source of exposure stepwise. DOF (nm) represents the focus range, i.e. the maximum difference among the distances in which the trench width is 40 nm±5% (38 to 42 nm).
Table 2 illustrates the results thereof.











TABLE 2







Resist Composition
Defects
DOF(nm)





















Ex. 10
Composition 1
230
105



Ex. 11
Composition 2
190
105



Ex. 12
Composition 3
170
105



Ex. 13
Composition 4
150
120



Ex. 14
Composition 5
160
120



Ex. 15
Composition 6
180
120



Ex. 16
Composition 7
130
105



Ex. 17
Composition 8
150
105



Ex. 18
Composition 9
180
120



Comparative
Comparative
490
75



Ex. 1
Comp. 1










Examples 19 to 20 and Comparative Example 2
<Evaluation of Resist Compositions: Positive Resist Patterns>
A composition for an organic antireflective film (“ARC-29”, by Nissan Chemical Co. Ltd.) was applied onto 12-inch silicon wafer and baked for 60 seconds at 205° C. to form a 78 nm thick organic antireflective film.
One of the resist compositions was then applied thereon by spin coating in such a manner that the thickness of the composition layer after drying (pre-baking) became 85 nm.
The obtained wafer was then pre-baked for 60 sec on a direct hot plate at the temperature given in the “PB” column in Table 1.
On the wafers on which the composition layer had thus been formed, the film was then exposed through a mask for forming contact hole patterns (hole pitch 100 nm/hole diameter 70 nm) with changing exposure quantity stepwise, using an ArF excimer laser stepper for liquid-immersion lithography (“XT:1900Gi” by ASML Ltd.: NA=1.35, 3/4 Annular XY-pol.). Ultrapure water was used as medium for liquid-immersion.
After the exposure, post-exposure baking was carried out for 60 seconds at the temperature given in the “PEB” column in Table 1.
Then, development was carried out with 2.38 wt % tetramethylammonium hydroxide (a product of Tokyo Chemical Industry Co., LTD) at 23° C. for 20 seconds in the manner of paddle development to obtain positive resist patterns.
Effective sensitivity was represented as the exposure quantity at which the resist pattern with 55 nm hole diameter was obtained using the mask having a 70 nm-hole diameter.
(Focus Margin (DOF) Evaluation)
DOF (nm) represents the focus range, i.e. the maximum difference among the distances in which the hole diameter is 55 nm±5% (52.5 to 57.7 nm).
Table 3 illustrates the results thereof.










TABLE 3







Resist Composition
DOF (nm)




















Ex. 19
Composition 1
240



Ex. 20
Composition 3
240



Comparative
Comparative
180



Ex. 2
Comp. 1










The compound, the resin including a structural unit derived from the compound of the disclosure is useful for resist compositions. A resist composition which includes the resin shows satisfactory excellent DOF and reduced defects even after storage for a certain period. Therefore, the compound, the resin and the resist composition of the disclosure are useful for semiconductor microfabrication.

## Claims

1. A resist composition comprising:
a resin which has no structural unit having an acid-labile group;
a resin having an acid-labile group; and
an acid generator;
the resin which has no structural unit having an acid-labile group
consisting of a structural unit derived from a compound represented by formula (I), or
consisting of a structural unit derived from a compound represented by formula (I) and a structural unit having an alicyclic hydrocarbon group but not having a fluorine atom, or
consisting of a structural unit derived from a compound represented by formula (I), a structural unit having an alicyclic hydrocarbon group but not having a fluorine atom, and a structural unit represented by formula (a4-0);




wherein R1 represents a hydrogen atom, a halogen atom or a C1 to C6 alkyl group in which a hydrogen atom may be replaced by a halogen atom,
R2 represents a —CH(Rf1)(Rf2),
Rf1 and Rf2 each independently represent a C1 to C6 perfluoroalkyl group,
A1 represents a single bond, a C1 to C6 alkanediyl group or *-A3-X1-(A4-X2)a-(A5)b-, 
* represents a binding site to an oxygen atom,
A2 represents a C2 to C6 branched alkanediyl group,
A3, A4 and A5 each independently represent a C1 to C6 alkanediyl group,
X1 and X2 each independently represent —O—, —CO—O— or —O—CO—,
W1 represents a C5 to C18 divalent alicyclic hydrocarbon group,
a represents 0 or 1, and
b represents 0 or 1;




wherein R5 represents a hydrogen atom or a methyl group,
L5 represents a single bond or a C 1 to C4 saturated aliphatic hydrocarbon group,
L3 represents a C1 to C8 perfluoroalkanediyl group, a C3 to C12 perfluorocycloalkanediyl group or a perfluoroadamantanediyl group, and
R6 represents a hydrogen atom or a fluorine atom.

2. A method for producing a resist pattern comprising steps (1) to (5):
(1) applying the resist composition according to claim 1 onto a substrate;
(2) drying the applied composition to form a composition layer;
(3) exposing the composition layer;
(4) heating the exposed composition layer; and
(5) developing the heated composition layer.

3. The resist composition according to claim 1, wherein
W1 is an adamantanediyl group or a cyclohexanediyl group.

4. The resist composition according to claim 3, wherein
the adamantanediyl group is any one of the groups represented by formulae (Ad-1) to (Ad-3);




wherein * is a binding site.

5. The resist composition according to claim 1, wherein
A1 is a single bond.