JP2017044875A - Radiation-sensitive resin composition, method for forming resist pattern, polymer and compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition excellent in PEB temperature dependency.SOLUTION: The radiation-sensitive resin composition comprises a polymer having a first structural unit containing a group represented by formula (1) below, a radiation-sensitive acid generator, and a solvent. In formula (1), Rrepresents a substituted or unsubstituted trivalent hydrocarbon group having 1 to 20 carbon atoms; and * represents a site to be bonded to a moiety excluding the group represented by formula (1) in the first structural unit.SELECTED DRAWING: None

Description

  The present invention relates to a radiation sensitive resin composition, a resist pattern forming method, a polymer, and a compound.

  With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, further miniaturization of resist patterns in the lithography process is required, and various radiation-sensitive resin compositions have been studied. Such a radiation sensitive resin composition generates an acid in an exposed portion by exposure to exposure light such as deep ultraviolet light such as ArF excimer laser, extreme ultraviolet light (EUV), and electron beam, and exposure is performed by catalytic action of this acid. A difference is caused in the dissolution rate with respect to the developing solution of the part and the unexposed part, and a resist pattern is formed on the substrate.

  Such a radiation sensitive resin composition is required to be excellent in various lithography performances such as resolution and to obtain a highly accurate pattern with a high yield. In particular, it is required that the variation of the resist pattern size due to the temperature of post-exposure heating (post-exposure baking (PEB)) is small, that is, excellent in PEB temperature dependency. In response to such demands, various studies have been made on the structure of the polymer contained in the radiation-sensitive resin composition (Japanese Patent Laid-Open Nos. 11-212265, 2003-5375, and 2008-). No. 83370).

  However, the above-mentioned conventional radiation-sensitive resin composition cannot satisfy such a requirement.

JP 11-212265 A JP 2003-5375 A JP 2008-83370 A

  This invention is made | formed based on the above situations, The objective is to provide the radiation sensitive resin composition excellent in PEB temperature dependence, the resist pattern formation method, a polymer, and a compound.

（式（１）中、Ｒ^１は、置換又は非置換の炭素数１〜２０の３価の炭化水素基である。＊は、上記第１構造単位における上記式（１）で表される基以外の部分と結合する部位を示す。） The invention made in order to solve the above-mentioned problems includes a first structural unit (hereinafter referred to as “structural unit (I)”) containing a group represented by the following formula (1) (hereinafter also referred to as “group (1)”). (Hereinafter also referred to as “[A] polymer”), a radiation sensitive acid generator (hereinafter also referred to as “[B] acid generator”), and a solvent (hereinafter referred to as “[C ] Solvent ").

(In Formula (1), R ¹ is a substituted or unsubstituted trivalent hydrocarbon group having 1 to 20 carbon atoms. * Is a group represented by Formula (1) in the first structural unit. The site | part couple | bonded with other parts is shown.)

  Another invention made in order to solve the above-mentioned problems comprises a step of forming a resist film, a step of exposing the resist film, and a step of developing the exposed resist film, It is the resist pattern formation method formed with a conductive resin composition.

（式（２）中、Ｒ^ａは、水素原子、フッ素原子又は炭素数１〜２０の１価の有機基である。Ｌは、単結合又は炭素数１〜２０の２価の有機基である。Ｒ^１は、上記式（１）と同義である。） Yet another invention made to solve the above problems is a polymer having a structural unit represented by the following formula (2).

(In Formula (2), ^Ra is a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹ has the same meaning as the above formula (1).)

（式（３）中、Ｒ^ａは、水素原子、フッ素原子又は炭素数１〜２０の１価の有機基である。Ｌは、単結合又は炭素数１〜２０の２価の有機基である。Ｒ^１は、置換又は非置換の炭素数１〜２０の３価の炭化水素基である。） Yet another invention made to solve the above problems is a compound represented by the following formula (3).

(In Formula (3), ^Ra is a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹ is a substituted or unsubstituted trivalent hydrocarbon group having 1 to 20 carbon atoms.

  Here, the “hydrocarbon group” refers to a group containing a chain hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group. The “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure but includes only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The term “alicyclic hydrocarbon group” refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, it is not necessary to be composed only of the alicyclic structure, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure. “Organic group” refers to a group containing at least one carbon atom.

  According to the radiation sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern can be formed while exhibiting excellent PEB temperature dependency. The polymer of this invention can be used suitably as a polymer component of the said radiation sensitive resin composition. The compound of the present invention can be suitably used as a monomer for the polymer. Accordingly, these can be suitably used for manufacturing semiconductor devices that are expected to be further miniaturized in the future.

<Radiation sensitive resin composition>
The radiation sensitive resin composition contains a [A] polymer, a [B] acid generator, and a [C] solvent. The radiation-sensitive resin composition includes, as suitable components, [D] acid diffusion controller, fluorine atom-containing polymer other than [A] polymer (hereinafter also referred to as “[E] polymer”) and / or [ F] An uneven distribution promoter may be contained, and other optional components may be contained as long as the effects of the present invention are not impaired. The radiation-sensitive resin composition may contain one or more of the above components. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer has the structural unit (I). The radiation-sensitive resin composition is excellent in PEB temperature dependency because the [A] polymer has the structural unit (I). The reason why the radiation-sensitive resin composition has the above-described configuration and thus exhibits the above-mentioned effects is not necessarily clear, but can be inferred as follows, for example. That is, since —O—C (S) —O— contained in the structural unit (I) of the polymer [A] has a sulfur atom that is superior in basicity to the oxygen atom, —O—C (O) It is excellent in basicity as compared with the structural unit having —O—. Therefore, it is considered that the [A] polymer further suppresses acid diffusion by having an appropriate polarity. As a result, it is considered that the radiation-sensitive resin composition is excellent in PEB temperature dependency.

  [A] The polymer is a structural unit (hereinafter referred to as a second structural unit containing an acid dissociable group (hereinafter also referred to as “structural unit (II)”), a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. , Also referred to as “structural unit (III)”) and / or a structural unit containing a hydroxy group (hereinafter also referred to as “structural unit (IV)”), and other than structural units (I) to (IV) Other structural units may be included. [A] The polymer may have one or more of the above structural units. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing the group (1). The group (1) is represented by the following formula (1).

In the above formula (1), R ¹ is a substituted or unsubstituted trivalent hydrocarbon group having 1 to 20 carbon atoms. * Indicates a site bonded to a moiety other than the group represented by the formula (1) in the first structural unit.

Examples of the trivalent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹ include a trivalent chain hydrocarbon group having 1 to 20 carbon atoms and a trivalent alicyclic carbon group having 3 to 20 carbon atoms. Examples thereof include a hydrogen group and a trivalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the trivalent chain hydrocarbon group having 1 to 20 carbon atoms include alkanetriyl groups such as a methanetriyl group, an ethanetriyl group, an n-propanetriyl group, and an i-propanetriyl group;
Alkenetriyl groups such as ethenetriyl group, propenetriyl group, butenetriyl group;
Examples thereof include alkynetriyl groups such as propynetriyl group and butynetriyl group.

Examples of the trivalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic cycloalkanetriyl groups such as cyclopentanetriyl group and cyclohexanetriyl group;
A monocyclic cycloalkenetriyl group such as a cyclopentenetriyl group or a cyclohexentriyl group;
A polycyclic cycloalkanetriyl group such as a norbornanetriyl group, an adamantanetriyl group, a tricyclodecanetriyl group;
Examples thereof include polycyclic cycloalkenetriyl groups such as norbornenetriyl group and tricyclodecentriyl group.

Examples of the trivalent aromatic hydrocarbon group having 6 to 20 carbon atoms include arenetriyl groups such as benzenetriyl group, toluenetoyl group and naphthalenetriyl group;
Arenetriylarenetriylalkanetriyl groups such as benzenetriylbenzenetriylmethanetriyl group, naphthalenetriylnaphthalenetriylmethanetriyl group;
Examples thereof include arenetriylalkanetriylalkanetriyl groups such as benzenetriylmethanetriylmethanetriyl group and naphthalenetriylmethanetriylmethanetriyl group.

Examples of the substituent of R ¹ include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, alkoxy group, cycloalkyloxy group, acyl group, acyloxy group, hydroxy group, carbonyl group, cyano group, Examples thereof include an amino group, a sulfanyl group, and a group obtained by combining two or more of these.

As the hydrocarbon group for R ¹ , a chain hydrocarbon group and an alicyclic hydrocarbon group are preferable, an alkanetriyl group and a cycloalkanetriyl group are more preferable, and ethanetriyl from the viewpoint of further improving PEB temperature dependency. More preferred are a group, a propanetriyl group, a butanetriyl group, a pentanetriyl group, a heptanetriyl group, a cyclopentanetriyl group and a cyclohexanetriyl group.

As the substituent that the hydrocarbon group of R ¹ has, a hydroxy group, a cyano group, an alkyloxy group, an alkoxycarbonyl group, and a cycloalkyloxy group are preferable from the viewpoint of further improving PEB temperature dependency.

  Examples of the group (1) include groups represented by the following formulas (a1) to (a18) (hereinafter also referred to as “groups (a1) to (a18)”).

  In the above formulas (a1) to (a18), * represents a site bonded to a portion other than the group (1) in the structural unit (I).

  Of these, the groups (a1) to (a14) are preferable.

  Examples of the structural unit (I) include a structural unit represented by the following formula (2) (hereinafter also referred to as “structural unit (I-1)”).

In said formula (2), ^Ra is a hydrogen atom, a fluorine atom, or a C1-C20 monovalent organic group. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹ has the same meaning as in the above formula (1).

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by ^Ra include, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon boundary of this hydrocarbon group, or a terminal on the bond side. Examples include a group (β) containing a divalent heteroatom-containing group, a group in which part or all of the hydrogen atoms of the hydrocarbon group and group (β) are substituted with a monovalent heteroatom-containing group.

  Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and 6 to 6 carbon atoms. 20 monovalent aromatic hydrocarbon groups and the like.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, and an i-propyl group;
An alkenyl group such as an ethenyl group, a propenyl group, a butenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group and butynyl group.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group;
A monocyclic cycloalkenyl group such as a cyclopentenyl group and a cyclohexenyl group;
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group and a tricyclodecyl group;
Examples thereof include polycyclic cycloalkenyl groups such as norbornenyl group and tricyclodecenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group and anthrylmethyl group.

  Examples of the hetero atom constituting the monovalent and divalent heteroatom-containing group include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, and a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Examples of the divalent heteroatom-containing group include —O—, —CO—, —S—, —CS—, —NR′—, a group in which two or more of these are combined, and the like. R ′ is a hydrogen atom or a monovalent organic group.

  Examples of the monovalent heteroatom-containing group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, amino group and sulfanyl group (—SH).

R ^a is a hydrogen atom, a chain hydrocarbon group, or a group containing —O— between the carbons of the chain hydrocarbon group from the viewpoint of copolymerization of the monomer that gives the structural unit (I). Preferably, a chain hydrocarbon group and a group containing —O— between the carbon-carbon of the chain hydrocarbon group are more preferable, an alkyl group and an alkyloxyalkyl group are more preferable, and a methyl group and a methyloxymethyl group are particularly preferable. .

Examples of the divalent organic group having 1 to 20 carbon atoms represented by L, such like groups obtained by removing monovalent illustrated one hydrogen atom from those organic groups of R ^a and the like.

  L is a chain hydrocarbon group, a group containing —O— at the terminal end of the chain hydrocarbon group, a group containing —CO— at the terminal end of the chain hydrocarbon group, A group containing —CO—O— at the terminal end of the bond side of the hydrocarbon group is preferable, an alkanediyl group, an oxyalkanediyl group, a carbonylalkanediyl group and an alkyloxycarbonylalkanediyl group are more preferable, a methanediyl group, n- More preferred are propanediyl, i-propanediyl, butanesyl, oxyethanediyl, carbonylmethanediyl and methanediyloxycarbonylmethanediyl.

  Examples of the structural unit (I-1) include compounds represented by the following formulas (I-1-1) to (I-1-30) (hereinafter referred to as “compounds (I-1-1) to (I-1)”. -30) ") and the like.

  Among these, as the structural unit (I-1), the structural units (I-1-1) to (I-1-21) are preferable.

  As a minimum of the content rate of structural unit (I), 1 mol% is preferable with respect to all the structural units which comprise a [A] polymer, 2 mol% is more preferable, 3 mol% is further more preferable, and 7 mol% % Is particularly preferred. As an upper limit of the content rate of structural unit (I), 80 mol% is preferable, 50 mol% is more preferable, 30 mol% is further more preferable, 20 mol% is especially preferable. By making the said content rate into the said range, PEB temperature dependence can be improved more.

  The compound giving the structural unit (I) (hereinafter also referred to as “compound (i)”) contains the group (1).

  Examples of the compound (i) include a compound represented by the following formula (3) (hereinafter also referred to as “compound (i-1)”).

In said formula (3), ^Ra is a hydrogen atom, a fluorine atom, or a C1-C20 monovalent organic group. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹ is a substituted or unsubstituted trivalent hydrocarbon group having 1 to 20 carbon atoms.

  As a synthesis scheme of the compound (i), for example, when the compound (i) is a compound represented by the following formula (i′-1) (hereinafter also referred to as “compound (i′-1)”), the following may be mentioned: It is done.

In the above scheme, R ^a and L are as defined in the above formula (3).

  A diol compound represented by the above formula (i-1-a) and a thiophosgene represented by the above formula (i-1-b) are reacted with tetrahydrofuran (THF) or the like in the presence of a base such as dimethylaminopyridine. Compound (i′-1) can be isolated by synthesizing compound (i′-1) by reacting in a solvent and appropriately purifying by column chromatography, recrystallization, distillation or the like. .

  According to the said synthesis method, a compound (i'-1) can be manufactured simply and with a sufficient yield.

  The compound (i) other than the compound (i′-1) can also be synthesized by the same method as described above.

[Structural unit (II)]
The structural unit (II) is a structural unit containing an acid dissociable group. The “acid-dissociable group” refers to a group that replaces a hydrogen atom such as a hydroxy group or a carboxy group and that dissociates by the action of an acid. [A] Since the polymer has the structural unit (II), the dissolution contrast between the exposed portion and the unexposed portion can be adjusted to an appropriate value, and as a result, the lithography performance of the radiation-sensitive resin composition. Can be improved.

  Examples of the structural unit (II) include a structural unit represented by the following formula (a-1) (hereinafter also referred to as “structural unit (II-1)”) and a structure represented by the following formula (a-2). Unit (hereinafter also referred to as “structural unit (II-2)”) and the like.

In the above formula (a-1), R ^A1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^A2 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^A3 and R ^A4 each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms, or have 3 to 20 ring members formed together with carbon atoms to which these groups are combined with each other. Represents an alicyclic structure.

In the above formula (a-2), R ^A5 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^A6 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^A7 and R ^A8 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms. L ^A is a single bond, -O -, - COO- or -CONH-.

  Here, the “number of ring members” refers to the number of atoms constituting the ring of the alicyclic structure and the aliphatic heterocyclic structure, and in the case of the polycyclic alicyclic structure and the polycyclic aliphatic heterocyclic structure, The number of atoms that make up the ring.

R ^A1 is preferably a hydrogen atom and a methyl group, and more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (II).

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^A2 , R ^A3 , R ^A4 , R ^A6 , R ^A7 and R ^A8 include a hydrocarbon group of R ^{a in} the above formula (2). And the same groups as those exemplified above.

Examples of the alicyclic structure having 3 to 20 carbon atoms configured together with the carbon atom to which these groups are combined and bonded to each other include a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, a cyclo Monocyclic cycloalkane structures such as octane structures;
Examples thereof include polycyclic cycloalkane structures such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure.

R ^A2 is preferably a chain hydrocarbon group and an alicyclic hydrocarbon group, more preferably an alkyl group and a cycloalkyl group, a methyl group, an ethyl group, a propyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and More preferred is an adamantyl group.

R ^A3 and R ^A4 include an alkyl group, a group in which these groups are combined with each other to form a monocyclic cycloalkane structure, a group in which these groups are combined with each other to form a norbornane structure, and the above groups. Are preferred to form an adamantane structure in which they are combined with each other, and a methyl group, an ethyl group, a cyclopentane structure, a group in which these groups are combined with each other to form a cyclohexane structure, and the above groups are combined with each other to form an adamantane structure More preferred are

R ^A5 is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, from the viewpoint of copolymerization of the monomer that gives the structural unit (II).

R ^A6 is preferably a chain hydrocarbon group.

Examples of the monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by the above R ^A7 and R ^A8 include carbon-carbon bonds or bonds of those exemplified as the R ^a hydrocarbon group of the above formula (2). Examples include those containing an oxygen atom at the end on the side.

R ^A7 and R ^A8 are preferably a chain hydrocarbon group and an alicyclic hydrocarbon group containing an oxygen atom.

As the ^{L A,} a single bond and -COO- is more preferably a single bond.

  Examples of the structural unit (II-1) include structural units represented by the following formulas (a-1-a) to (a-1-d) (hereinafter referred to as “structural units (II-1-a) to (II)”. -1-d) ”) and the like.

  Examples of the structural unit (II-2) include a structural unit represented by the following formula (a-2-a) (hereinafter also referred to as “(II-2-a)”).

In the formulas (a-1-a) to (a-1-d), R ^{A1 to} R ^A4 have the same meanings as the formula (a-1). n _a is an integer of 1 to 4. In the above formula (a-2-a), R ^{A5 to} R ^A8 have the same ^meanings as the above formula (a-2).

The n _a, preferably 1, 2 and 4, more preferably 1.

  Examples of the structural units (II-1-a) to (II-1-d) include structural units represented by the following formulas.

In the above formula, R ^A1 has the same ^{meaning as} the above formula (a-1).

  Examples of the structural unit (II-2-a) include a structural unit represented by the following formula.

In the above formula, R ^A5 has the same ^{meaning as} in the above formula (a-2).

  As the structural unit (II), the structural unit (II-1) is preferable, the structural units (II-1-a), (II-1-b) and (II-1-d) are more preferable, and 1-alkyl Structural units derived from -1-cycloalkyl (meth) acrylate, structural units derived from 2-cycloalkane-1-yl) alkane-2-yl (meth) acrylate, and 2-alkyl-2-adamantyl (meth) acrylate The structural unit derived from is more preferable.

  [A] When the polymer has the structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 10 mol% with respect to all structural units constituting the [A] polymer, % Is more preferable, and 20 mol% is more preferable. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 60 mol% is further more preferable. By making the said content rate into the said range, the dissolution contrast of an exposed part and an unexposed part can be adjusted to a moderate thing, As a result, the lithography performance of the said radiation sensitive resin composition can be improved. it can.

[Structural unit (III)]
The structural unit (III) is a structural unit including a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. [A] Since the polymer further has the structural unit (III), the solubility in the developer can be adjusted to an appropriate level, and as a result, the lithography performance of the radiation-sensitive resin composition is improved. Can be made. In addition, the adhesion between the formed resist pattern and the substrate can be improved.

  Examples of the structural unit (III) include a structural unit represented by the following formula.

In the above formula, R ^L1 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  Among these, the structural unit (III) is preferably a structural unit containing a γ-butyrolactone structure, a structural unit containing a norbornane lactone structure, a structural unit containing an oxanorbornane lactone structure, or a structural unit containing a norbornane sultone structure, -Structural unit derived from butyrolactone-yl (meth) acrylate, structural unit derived from norbornanelactone-yl (meth) acrylate, structural unit derived from cyano-substituted norbornanelactone-yl (meth) acrylate, oxanorbornanelactone-yl ( A structural unit derived from (meth) acrylate and a structural unit derived from norbornane sultone-yl (meth) acrylate are more preferred.

  [A] When the polymer has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 10 mol% with respect to all the structural units constituting the [A] polymer. More preferably, mol% is more preferable, and 20 mol% is still more preferable. As an upper limit of the said content rate, 70 mol% is preferable, 60 mol% is more preferable, and 55 mol% is further more preferable. Lithography performance can be improved more by making the said content rate into the said range. Further, the adhesion of the formed resist pattern to the substrate can be further improved.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing a hydroxy group. [A] By having the structural unit (IV), the polymer can adjust the solubility in the developer more appropriately, and as a result, the lithography performance can be improved. In addition, the adhesion between the formed resist pattern and the substrate can be improved.

  Examples of the hydroxy group include alcoholic hydroxy groups and phenolic hydroxy groups.

  Examples of the structural unit (IV) include a structural unit represented by the following formula.

In the above formula, R ^AH is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  Among these, a structural unit having a hydroxyadamantyl group is preferable, and a structural unit derived from 3-hydroxyadamantyl (meth) acrylate is more preferable.

  [A] When the polymer has a structural unit (IV), the lower limit of the content ratio of the structural unit (IV) is preferably 3 mol% with respect to all the structural units constituting the polymer [A], and 5 mol. % Is more preferable. As an upper limit of the said content rate, 35 mol% is preferable, 30 mol% is preferable, and 25 mol% is more preferable.

[Other structural units]
[A] The polymer may have other structural units other than the structural units (I) to (IV). Examples of the other structural units include structural units having a carboxy group, a cyano group, a nitro group, a sulfonamide group, and the like. [A] When the polymer has other structural units, the upper limit of the content ratio of the other structural units is preferably 60 mol%, and 50 mol% with respect to all the structural units constituting the [A] polymer. More preferred.

  [A] The lower limit of the content of the polymer is preferably 70% by mass, more preferably 80% by mass with respect to the total solid content of the radiation-sensitive resin composition (total of components other than the solvent), 85 More preferred is mass%.

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized, for example, by polymerizing monomers that give each structural unit in a suitable solvent using a radical polymerization initiator or the like.

Examples of radical polymerization initiators include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis (2-cyclopropylpropylene). Pionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), azo radical initiators such as dimethyl 2,2′-azobisisobutyrate;
And peroxide radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, and the like. Of these, AIBN and dimethyl 2,2′-azobisisobutyrate are preferred, and AIBN is more preferred. These radical polymerization initiators can be used alone or in combination of two or more.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, butanone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. The solvent used for these polymerizations may be used alone or in combination of two or more.

  As a minimum of reaction temperature in superposition | polymerization, 40 degreeC is preferable and 50 degreeC is more preferable. As an upper limit of the said reaction temperature, 150 degreeC is preferable and 120 degreeC is more preferable. As a minimum of reaction time in superposition | polymerization, 1 hour is preferable and 2 hours is more preferable. The upper limit of the reaction time is preferably 48 hours, more preferably 24 hours.

  [A] The lower limit of the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is preferably 1,000, more preferably 2,000, still more preferably 3,000, 000 is particularly preferred. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 15,000. [A] By making Mw of a polymer into the said range, the applicability | paintability of the said radiation sensitive resin composition can be improved.

  [A] The upper limit of the ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is preferably 5, more preferably 3, still more preferably 2, and particularly preferably 1.7. . The lower limit of the ratio is usually 1 and preferably 1.1.

Mw and Mn of the polymer in this specification are values measured using gel permeation chromatography (GPC) under the following conditions.
GPC column: For example, two “G2000HXL”, one “G3000HXL” and one “G4000HXL” manufactured by Tosoh Corporation Column temperature: 40 ° C.
Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

<[B] Acid generator>
[B] The acid generator is a substance that generates an acid upon exposure. This generated acid dissociates the acid-dissociable group of the [A] polymer and the like to generate a carboxy group, a hydroxy group, and the like, and the solubility of the [A] polymer in the developer changes. A resist pattern can be formed from the conductive resin composition. The contained form of the [B] acid generator in the radiation-sensitive resin composition may be a low molecular compound form (hereinafter also referred to as “[B] acid generator” as appropriate), as described later. It may be in the form of an acid generating group incorporated as a part, or in both forms.

  [B] Examples of the acid generator include onium salt compounds, N-sulfonyloxyimide compounds, sulfonimide compounds, halogen-containing compounds, and diazoketone compounds.

  Examples of the onium salt compounds include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.

  [B] Specific examples of the acid generator include compounds described in paragraphs [0080] to [0113] of JP-A-2009-134088.

  [B] The acid generator is preferably an acid generator represented by the following formula (b). [B] Since the acid generator has the following structure, [A] the diffusion length of the acid generated by exposure in the resist film due to the interaction with the structural unit (I) or the structural unit (II) of the polymer, etc. As a result, the lithography performance of the radiation-sensitive resin composition can be further improved.

In the above formula (b), R ^p1 is a monovalent group containing a ring structure having 6 or more ring members. R ^p2 is a divalent linking group. R ^p3 and R ^p4 are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ^p5 and R ^p6 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. n ^p1 is an integer of 0 to 10. n ^p2 is an integer of 0 to 10. n ^p3 is an integer of 1 to 10. When n ^p1 is 2 or more, the plurality of R ^p2 may be the same or different. When n ^p2 is 2 or more, the plurality of R ^p3 may be the same or different, and the plurality of R ^p4 may be the same or different. When n ^p3 is 2 or more, the plurality of R ^p5 may be the same or different, and the plurality of R ^p6 may be the same or different. X ⁺ is a monovalent radiation-sensitive onium cation.

Examples of the monovalent group including a ring structure having 6 or more ring members represented by R ^p1 include a monovalent group including an alicyclic structure having 6 or more ring members and an aliphatic heterocyclic structure having 6 or more ring members. A monovalent group, a monovalent group containing an aromatic ring structure having 6 or more ring members, a monovalent group containing an aromatic heterocyclic structure having 6 or more ring members, and the like.

Examples of the alicyclic structure having 6 or more ring members include monocyclic cycloalkane structures such as a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure;
Monocyclic cycloalkene structures such as cyclohexene structure, cycloheptene structure, cyclooctene structure, cyclodecene structure;
Polycyclic cycloalkane structures such as norbornane structure, adamantane structure, tricyclodecane structure and tetracyclododecane structure;
Examples thereof include polycyclic cycloalkene structures such as a norbornene structure and a tricyclodecene structure.

Examples of the aliphatic heterocyclic structure having 6 or more ring members include lactone structures such as a hexanolactone structure and a norbornane lactone structure;
Sultone structures such as hexanosultone structure and norbornane sultone structure;
An oxygen atom-containing heterocyclic structure such as an oxacycloheptane structure or an oxanorbornane structure;
Nitrogen atom-containing heterocyclic structures such as azacyclohexane structure and diazabicyclooctane structure;
Examples thereof include a sulfur atom-containing heterocyclic structure having a thiacyclohexane structure and a thianorbornane structure.

Examples of the aromatic ring structure having 6 or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, and an anthracene structure.

  Examples of the aromatic heterocyclic structure having 6 or more ring members include oxygen atom-containing heterocyclic structures such as furan structure, pyran structure and benzopyran structure, nitrogen atom-containing heterocyclic structures such as pyridine structure, pyrimidine structure and indole structure. Can be mentioned.

The lower limit of the number of ring members of the ring structure of R ^p1 is preferably 7, more preferably 8, more preferably 9, and particularly preferably 10. On the other hand, the upper limit of the number of ring members is preferably 15, more preferably 14, still more preferably 13, and particularly preferably 12. By setting the number of ring members in the above range, the above-described acid diffusion length can be further appropriately shortened, and as a result, the lithography performance can be further improved.

A part or all of the hydrogen atoms ^{contained in} the ring structure of R ^p1 may be substituted with a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, Examples include an acyloxy group. Of these, a hydroxy group is preferred.

Among these, R ^p1 is preferably a monovalent group containing an alicyclic structure having 6 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members, and an alicyclic group having 9 or more ring members. A monovalent group containing a ring structure and a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members are more preferred. An oxo-4-oxatricyclo [4.3.1.1 ^3,8 ] undecan-yl group is more preferred, and an adamantyl group is particularly preferred.

Examples of the divalent linking group represented by R ^p2 include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, and a divalent hydrocarbon group. The divalent linking group represented by R ^p2 is preferably a carbonyloxy group, a sulfonyl group, an alkanediyl group and a cycloalkanediyl group, more preferably a carbonyloxy group and a cycloalkanediyl group, a carbonyloxy group and a norbornanediyl group. A group is more preferred, and a carbonyloxy group is particularly preferred.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 include an alkyl group having 1 to 20 carbon atoms. Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 include a fluorinated alkyl group having 1 to 20 carbon atoms. R ^p3 and R ^p4 are preferably a hydrogen atom, a fluorine atom and a fluorinated alkyl group, more preferably a fluorine atom and a perfluoroalkyl group, and still more preferably a fluorine atom and a trifluoromethyl group.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p5 and R ^p6 include a fluorinated alkyl group having 1 to 20 carbon atoms. R ^p5 and R ^p6 are preferably a fluorine atom and a fluorinated alkyl group, more preferably a fluorine atom and a perfluoroalkyl group, still more preferably a fluorine atom and a trifluoromethyl group, and particularly preferably a fluorine atom.

The n ^p1, preferably an integer of 0 to 5, more preferably an integer of 0 to 3, more preferably an integer of 0 to 2, 0 and 1 are particularly preferred.

The n ^p2, preferably an integer of 0 to 5, more preferably an integer of 0 to 2, more preferably 0 and 1, 0 being particularly preferred.

As ^np3 , the integer of 1-5 is preferable, the integer of 1-4 is more preferable, the integer of 1-3 is more preferable, and 1 and 2 are especially preferable.

The monovalent radiation-sensitive onium cation represented by X ⁺ is a cation that decomposes upon exposure to exposure light. In the exposed portion, sulfonic acid is generated from protons generated by the decomposition of the photodegradable onium cation and a sulfonate anion. Examples of the monovalent radiation-sensitive onium cation represented by X ⁺ include a cation represented by the following formula (ba) (hereinafter also referred to as “cation (ba)”), and the following formula (b -B) (hereinafter also referred to as "cation (bb)"), a cation represented by the following formula (bc) (hereinafter also referred to as "cation (bc)"), and the like Is mentioned.

In the above formula (ba), R ^B3 , R ^B4 and R ^B5 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted group. An aromatic hydrocarbon group having 6 to 12 carbon atoms, —OSO ₂ —R ^BB1 or —SO ₂ —R ^BB2 , or a ring structure in which two or more of these groups are combined with each other . R ^BB1 and R ^BB2 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. b1, b2 and b3 are each independently an integer of 0 to 5. R ^B3 to R ^B5 and, if a plurality ^{R BB1} and ^{R BB2} are each the plurality of ^R B3 ^{to R B5} and ^{R BB1} and ^{R BB2} may each be the same or different.

In the above formula (bb), R ^B6 represents a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms. It is. b4 is an integer of 0-7. If R ^B6 is plural, the plurality of R ^B6 may be the same or different, and plural R ^B6 may represent a constructed ring aligned with each other.
R ^B7 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. b5 is an integer of 0-6. If R ^B7 is plural, R ^B7 may be the same or different, and plural R ^B7 may represent a keyed configured ring structure. n _b2 is an integer of 0 to 3. R ^B8 is a single bond or a divalent organic group having 1 to 20 carbon atoms. n _b1 is an integer of 0-2.

In the above formula ( ^bc ), R ^B9 and R ^B10 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 6 12 aromatic hydrocarbon _group, or an -OSO ^{2 -R BB3} or _-SO 2 ^{-R BB4,} or two or more are combined with each other configured ring of these groups. R ^BB3 and R ^BB4 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. b6 and b7 are each independently an integer of 0 to 5. ^{R B9,} R B10, R ^BB3 and when ^{R BB4} is plural respective plurality of ^{R B9, R B10, R BB3} and ^{R BB4} may have respectively the same or different.

As the unsubstituted linear alkyl group represented by R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 , for example, a methyl group, an ethyl group, an n-propyl group, an n- A butyl group etc. are mentioned.

Examples of the unsubstituted branched alkyl group represented by R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include an i-propyl group, i-butyl group, and sec-butyl group. , T-butyl group and the like.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^B3 , R ^B4 , R ^B5 , R ^B9 and R ^B10 include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group and a naphthyl group; benzyl Group, an aralkyl group such as a phenethyl group, and the like.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^B6 and R ^B7 include a phenyl group, a tolyl group, and a benzyl group.

Examples of the divalent organic group represented by R ^B8 include groups similar to those exemplified as the divalent organic group of L in the above formula (2).

  Examples of the substituent that may be substituted for the hydrogen atom of the alkyl group and the aromatic hydrocarbon group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a hydroxy group, a carboxy group, a cyano group, Examples thereof include a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, and an acyloxy group. Among these, a halogen atom is preferable and a fluorine atom is more preferable.

R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic carbonization A hydrogen group, —OSO ₂ —R ^BB5 and —SO ₂ —R ^BB5 are preferred, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferred, and a fluorinated alkyl group is more preferred. R ^BB5 is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As b1, b2, and b3 in the formula (ba), integers of 0 to 2 are preferable, 0 and 1 are more preferable, and 0 is more preferable. As b4 in Formula (bb), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 1 is more preferable. As b5, the integer of 0-2 is preferable, 0 and 1 are more preferable, and 0 is still more preferable. As _nb2 , 2 and 3 are preferable and 2 is more preferable. As _nb1 , 0 and 1 are preferable and 0 is more preferable. As b6 and b7 in the formula (bc), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is more preferable.

Among these, cation (ba) and cation (bb) are preferable as X ⁺ , and triphenylsulfonium cation and 1- [2- (4-cyclohexylphenylcarbonyl) propan-2-yl] tetrahydro A thiophenium cation is more preferred.

  Examples of the acid generator represented by the formula (b) include compounds represented by the following formulas (b-1) to (b-15) (hereinafter, “compounds (b-1) to (b-15)”). Also).

In the above formulas (b-1) to (b-15), X ⁺ is a monovalent radiation-sensitive onium cation.

  [B] As the acid generator, an onium salt compound is preferable, and compounds (b-1), (b-2), (b-11) and (b-12) are more preferable.

  [B] When the acid generator is a [B] acid generator, the lower limit of the content of the [B] acid generator is preferably 0.1 parts by mass with respect to 100 parts by mass of the [A] polymer. 0.5 mass part is more preferable, and 1 mass part is further more preferable. As an upper limit of the said content, 30 mass parts is preferable, 20 mass parts is more preferable, and 15 mass parts is further more preferable. [B] By making content of an acid generator into the said range, the sensitivity and developability of the said radiation sensitive resin composition can be improved.

<[C] solvent>
[C] The solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the [A] polymer, the [B] acid generator, and the optionally contained [D] acid diffusion controller.

  [C] Examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

Examples of alcohol solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec -Monoalcohol solvents such as heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 -Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, and polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
Aromatic ring-containing ether solvents such as diphenyl ether and anisole (methylphenyl ether) are exemplified.

Examples of the ketone solvent include acetone, butanone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone (methyl-n-pentyl ketone), and ethyl-n-butyl ketone. Chain ketone solvents such as methyl-n-hexyl ketone, di-iso-butyl ketone, and trimethylnonanone;
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone;
2,4-pentanedione, acetonylacetone, acetophenone and the like can be mentioned.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of the ester solvent include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, i-pentyl acetate, sec -Acetate solvents such as pentyl, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Polyhydric alcohol partial ether acetate solvents such as acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
Carbonate solvents such as dimethyl carbonate and diethyl carbonate;
Glycol acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl acetoacetate, ethyl acetoacetate, methyl lactate, ethyl lactate N-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of the hydrocarbon solvent include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, and cyclohexane. , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene and n-amylnaphthalene Group hydrocarbon solvents and the like.

  Among these, ester solvents and ketone solvents are preferable, polyhydric alcohol partial ether acetate solvents, lactone solvents and cyclic ketone solvents are more preferable, and propylene glycol monomethyl ether acetate and cyclohexanone are more preferable.

<[D] Acid diffusion controller>
The said radiation sensitive resin composition may contain the [D] acid diffusion control body as needed. [D] The acid diffusion controller controls the diffusion phenomenon in the resist film of the acid generated from the [B] acid generator by exposure, and has an effect of suppressing an undesirable chemical reaction in the non-exposed region. Moreover, the storage stability of the radiation sensitive resin composition is improved. Furthermore, a change in the size of the resist pattern due to fluctuations in the holding time from exposure to development processing can be suppressed, and a radiation-sensitive resin composition excellent in process stability can be obtained. [D] The content of the acid diffusion controller in the radiation-sensitive resin composition is incorporated as a part of the polymer even in the form of a free compound (hereinafter referred to as “[D] acid diffusion controller” as appropriate). Or both of these forms.

  [D] Examples of the acid diffusion controller include a compound represented by the following formula (c-1) (hereinafter also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule ( Hereinafter, also referred to as “nitrogen-containing compound (II)”, compounds having three nitrogen atoms (hereinafter also referred to as “nitrogen-containing compound (III)”), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, etc. Is mentioned.

In the above formula (c-1), R ^C1 , R ^C2 and R ^C3 each independently represent a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, aryl group or aralkyl group. Or a ring structure in which two or more of these are combined with each other and the nitrogen atom to which they are attached.

Examples of the nitrogen-containing compound (I) include monoalkylamines such as tri-n-pentylamine;
Dialkylamines such as di-n-butylamine;
Trialkylamines such as triethylamine, triethanolamine, triacetyltriethanolamine;
Aromatic amines such as aniline, 2,6-di-i-propylaniline, N, N-di-n-butylaniline;
Nt-acyloxycarbonyl-4-hydroxypiperidine and the like can be mentioned.

  Among these, as the nitrogen-containing compound (I), monoalkylamines and aromatic amines are preferable, and tri-n-pentylamine and 2,6-di-i-propylaniline are more preferable.

  Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, and the like.

Examples of the nitrogen-containing compound (III) include polyamine compounds such as polyethyleneimine and polyallylamine;
Examples thereof include polymers such as dimethylaminoethylacrylamide.

  Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. It is done.

  Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like.

Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine;
Morpholines such as N-propylmorpholine and N- (undecylcarbonyloxyethyl) morpholine;
Examples include pyrazine and pyrazole.

  Among these, as the nitrogen-containing heterocyclic compound, morpholines are preferable, and N- (undecylcarbonyloxyethyl) morpholine is more preferable.

  [D] A nitrogen-containing organic compound having an acid-dissociable group can also be used as the acid diffusion controller. Examples of the nitrogen-containing organic compound having such an acid dissociable group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2. -Phenylbenzimidazole, N- (t-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine and the like.

  Further, as the [D] acid diffusion control agent, a photodisintegratable base that is exposed to light and generates a weak acid by exposure can also be used. Examples of the photodegradable base include an onium salt compound that loses acid diffusion controllability by being decomposed by exposure. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (c-2), an iodonium salt compound represented by the following formula (c-3), and the like.

In formula (c-2) and formula (c-3), R ^{C4 to} R ^C8 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group, or a halogen atom. E ⁻ and Q ⁻ are each independently an anion represented by OH ⁻ , R ^CC1 —COO ⁻ , R ^CC1 —SO ₃ ^— or the following formula (c-4). However, R ^CC1 is an alkyl group, an aryl group, or an aralkyl group.

In the above formula (c-4), R ^C9 represents a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched fluorinated alkyl group having 1 to 12 carbon atoms, or a carbon number of 1 -12 linear or branched alkoxy groups. n _c is an integer of 0-2. If n _c is 2, two ^{R C9} may be the same or different.

  More specifically, examples of the photodegradable base include compounds represented by the following formulas.

  Among these, as the photodegradable base, a sulfonium salt is preferable, a triarylsulfonium salt is more preferable, and triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate are more preferable.

  When the said radiation sensitive resin composition contains a [D] acid diffusion control agent as a [D] acid diffusion control body, as a minimum of content of a [D] acid diffusion control agent, [A] 100 mass of polymers 0.1 parts by mass is preferable, 0.3 parts by mass is more preferable, and 1 part by mass is more preferable. As an upper limit of the said content, 20 mass parts is preferable, 15 mass parts is more preferable, and 10 mass parts is further more preferable.

<[E] polymer>
The said radiation sensitive resin composition may contain the [E] polymer as needed. The [E] polymer is a polymer different from the [A] polymer, and is a fluorine atom-containing polymer. When the radiation sensitive resin composition contains the [E] polymer, when the resist film is formed, the distribution is unevenly distributed near the resist film surface due to the oil-repellent characteristics of the fluoropolymer in the film. There is a tendency to become. Therefore, it is possible to suppress the acid generator, the acid diffusion controller, and the like from being eluted into the immersion medium during the immersion exposure. Further, due to the water-repellent characteristics of the [E] polymer, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range, and the occurrence of bubble defects can be suppressed. Furthermore, the receding contact angle between the resist film and the immersion medium is increased, and high-speed scanning exposure is possible without leaving water droplets. Thus, when the said radiation sensitive resin composition contains an [E] polymer, the resist film suitable for an immersion exposure method can be formed.

  [E] The polymer is not particularly limited as long as it is a polymer having a fluorine atom, but the fluorine atom content (% by mass) is higher than that of the [A] polymer in the radiation-sensitive resin composition. It is preferable. [A] When the fluorine atom content is higher than that of the polymer, the degree of uneven distribution described above becomes higher, and characteristics such as water repellency and elution suppression of the resulting resist film are improved.

[E] The lower limit of the fluorine atom content of the polymer is preferably 1% by mass, more preferably 2% by mass, further preferably 4% by mass, and particularly preferably 7% by mass. The upper limit of the fluorine atom content is preferably 60% by mass, more preferably 40% by mass, and even more preferably 30% by mass. [E] When the fluorine atom content of the polymer is less than the lower limit, the hydrophobicity of the resist film surface may be lowered. The fluorine atom content (% by mass) of the polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR spectrum measurement or the like.

  [E] The polymer preferably has the following structural unit (Ea), the following structural unit (Eb), or a combination thereof. [E] The polymer may have one or more structural units (Ea) and structural units (Eb).

[Structural unit (Ea)]
The structural unit (Ea) is a structural unit represented by the following formula (ff1). [E] A polymer can adjust a fluorine atom content rate by having a structural unit (Ea).

In the above formula (ff1), R ^F1 represents a hydrogen atom, a methyl group or a trifluoromethyl group. L ^F1 is a single bond, an oxygen atom, a sulfur atom, —CO—O—, —SO ₂ —O—NH—, —CO—NH—, or —O—CO—NH—. R ^F2 is a monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms.

Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by R ^F2 include trifluoromethyl group, 2,2,2-trifluoroethyl group, perfluoroethyl group, 2,2 , 3,3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, perfluoro n-propyl group, perfluoro i-propyl group, perfluoro n-butyl group, Examples include perfluoro i-butyl group, perfluoro t-butyl group, 2,2,3,3,4,4,5,5-octafluoropentyl group, perfluorohexyl group and the like.

Examples of the monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^F2 include a monofluorocyclopentyl group, a difluorocyclopentyl group, a perfluorocyclopentyl group, a monofluorocyclohexyl group, a difluorocyclopentyl group, Examples include a perfluorocyclohexylmethyl group, a fluoronorbornyl group, a fluoroadamantyl group, a fluorobornyl group, a fluoroisobornyl group, a fluorotricyclodecyl group, and a fluorotetracyclodecyl group.

  Examples of the monomer that gives the structural unit (Ea) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, and 2,2,2-trifluoroethyloxy. Carbonylmethyl (meth) acrylic acid ester, perfluoroethyl (meth) acrylic acid ester, perfluoro n-propyl (meth) acrylic acid ester, perfluoro i-propyl (meth) acrylic acid ester, perfluoro n-butyl (meta ) Acrylic acid ester, perfluoro i-butyl (meth) acrylic acid ester, perfluoro t-butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexafluoropropyl) (meta ) Acrylic acid ester, 1- (2,2,3,3,4,4,5,5-octafluorope Chill) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic acid ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, monofluorocyclopentyl (meth) Acrylic acid ester, difluorocyclopentyl (meth) acrylic acid ester, perfluorocyclopentyl (meth) acrylic acid ester, monofluorocyclohexyl (meth) acrylic acid ester, difluorocyclopentyl (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic Acid ester, fluoronorbornyl (meth) acrylic acid ester, fluoroadamantyl (meth) acrylic acid ester, fluorobornyl (meth) acrylic acid ester, fluoroisobornyl (meta Acrylic acid esters, fluoro tricyclodecyl (meth) acrylate, fluoro tetracyclododecene decyl (meth) acrylic acid ester. Among these, 2,2,2-trifluoroethyloxycarbonylmethyl (meth) acrylic acid ester is preferable.

  [E] When the polymer has a structural unit (Ea), the lower limit of the content ratio of the structural unit (Ea) is preferably 5 mol% with respect to all structural units constituting the [E] polymer. More preferably, mol% is more preferable, and 20 mol% is still more preferable. As an upper limit of the said content rate, 100 mol% may be sufficient, 95 mol% is preferable, 85 mol% is more preferable, and 80 mol% is further more preferable. By setting the content ratio within the above range, a higher dynamic contact angle on the resist film surface can be expressed during immersion exposure.

[Structural unit (Eb)]
The structural unit (Eb) is a structural unit represented by the following formula (ff2). Since the [E] polymer has the structural unit (Eb) and becomes hydrophobic, the dynamic contact angle of the resist film surface formed from the radiation-sensitive resin composition can be further improved.

In formula (ff2), R ^F3 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^F4 is a (u + 1) -valent hydrocarbon group having 1 to 20 carbon atoms, and an oxygen atom, a sulfur atom, —NR′—, a carbonyl group, —CO—O—, or a terminal on the R ^F5 side of R ^F4 Also includes a structure in which —CO—NH— is bonded. R ′ is a hydrogen atom or a monovalent organic group. R ^F5 is a single bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms, or a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms. L ^F2 is a divalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms. L ^F3 is an oxygen atom, —NR ″ —, —CO—O— * ^f, or —SO ₂ —O— * ^f . R ″ is a hydrogen atom or a monovalent organic group. * ^F represents a binding site that binds to R ^F6 . R ^F6 is a hydrogen atom or a monovalent organic group. u is an integer of 1 to 3. However, when u is 2 or 3, a plurality of R ^F5 , L ^F2 , L ^F3 and R ^F6 may be the same or different.

When R ^F6 is a hydrogen atom, it is preferable in that the solubility of the [E] polymer in an alkaline developer can be improved.

Examples of the monovalent organic group represented by R ^F6 include an acid dissociable group, an alkali dissociable group, and a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent.

  Examples of the structural unit (Eb) include structural units represented by the following formulas (ff2-1) to (ff2-3).

In the above formulas (ff2-1) to (ff2-3), R ^{F4 ′} is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. R ^F3 , L ^F2 , R ^F6 and u are synonymous with the above formula (ff2). When u is 2 or 3, the plurality of L ^F2 and R ^F6 may be the same or different.

  [E] When a polymer has a structural unit (ff2), as a minimum of the content rate of a structural unit (ff2), 5 mol% is preferable with respect to all the structural units which comprise a [E] polymer, 10 Mole% is more preferable, and 15 mol% is more preferable. As an upper limit of the said content rate, 90 mol% is preferable, 85 mol% is more preferable, and 80 mol% is further more preferable. By making the said content rate into the said range, the resist film surface formed from the said radiation sensitive resin composition can improve the fall degree of a dynamic contact angle in alkali image development.

[Structural unit (Ec)]
[E] The polymer may have a structural unit containing an acid-dissociable group (hereinafter also referred to as “structural unit (Ec)”) in addition to the structural units (Ea) and (Eb) (however, Except those corresponding to the structural unit (Eb)). [E] When the polymer has the structural unit (Ec), the shape of the resulting resist pattern becomes better. Examples of the structural unit (Ec) include the structural unit (II) in the above-mentioned [A] polymer.

  [E] When the polymer has a structural unit (Ec), the lower limit of the content ratio of the structural unit (Ec) is preferably 5 mol% with respect to all the structural units constituting the [E] polymer, % Is more preferable, and 60 mol% is more preferable. As an upper limit of the said content rate, 90 mol% is preferable, 85 mol% is more preferable, and 80 mol% is further more preferable.

[Other structural units]
[E] In addition to the above structural units, the [E] polymer may be, for example, a structural unit containing an alkali-soluble group, a lactone structure, a cyclic carbonate structure, a sultone structure, a structural unit containing a combination thereof, or a structure containing an alicyclic group. You may have other structural units, such as a unit. Examples of the alkali-soluble group include a carboxy group, a sulfonamido group, and a sulfo group. Examples of the structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof include the structural unit (III) in the above-mentioned [A] polymer.

  As an upper limit of the content rate of another structural unit, 30 mol% is preferable with respect to all the structural units which comprise a [E] polymer, and 20 mol% is more preferable.

  When the said radiation sensitive resin composition contains a [E] polymer, as a minimum of content of a [E] polymer, 0.5 mass part is with respect to 100 mass parts of a [A] polymer. Preferably, 1 part by mass is more preferable, and 2 parts by mass is more preferable. As an upper limit of the said content, 20 mass parts is preferable, 15 mass parts is more preferable, and 10 mass parts is further more preferable.

[[F] uneven distribution promoter]
The [F] uneven distribution accelerator has the effect of more efficiently segregating the [E] polymer on the resist film surface when the radiation sensitive resin composition contains the [F] uneven distribution accelerator. It is what you have. By adding this [F] uneven distribution promoter to the radiation sensitive resin composition, the amount of the [E] polymer added can be reduced as compared with the conventional case. Therefore, it is possible to further suppress the elution of components from the dyst film to the immersion liquid and to perform immersion exposure at a higher speed by high-speed scanning, and as a result, to suppress immersion-derived defects such as watermark defects. It is possible to improve the hydrophobicity of the resist film surface. Examples of such [F] uneven distribution promoters include low molecular compounds having a relative dielectric constant of 30 to 200 and a boiling point of 100 ° C. at 1 atm. Specific examples of such compounds include lactone compounds, carbonate compounds, nitrile compounds, and polyhydric alcohols.

  Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone, and the like. Examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, and the like. Examples of the nitrile compound include succinonitrile. Examples of the polyhydric alcohol include glycerin.

  [F] The uneven distribution promoter is preferably a lactone compound, more preferably γ-butyrolactone.

  When the said radiation sensitive resin composition contains [F] uneven distribution promoter, as a minimum of content of [F] uneven distribution accelerator, the total amount of the polymer in the said radiation sensitive resin composition is 100 mass parts On the other hand, 10 mass parts is preferable, 15 mass parts is more preferable, 20 mass parts is further more preferable, and 25 mass parts is especially preferable. As an upper limit of the said content, 500 mass parts is preferable, 300 mass parts is more preferable, 200 mass parts is further more preferable, 100 mass parts is especially preferable.

<Other optional components>
The said radiation sensitive resin composition may contain other arbitrary components other than the said [A]-[F] component. Examples of the other optional components include surfactants, alicyclic skeleton-containing compounds, and sensitizers. Each of these other optional components may be used alone or in combination of two or more.

[Surfactant]
The surfactant exhibits an effect of improving applicability, striation, developability and the like when the radiation-sensitive resin composition contains a surfactant. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. Nonionic surfactants such as stearate are listed. Examples of commercially available surfactants include KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, Tochem Products), MegaFuck F171, F173 (above, DIC), Florard FC430, FC431 (above, Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, Asahi Glass Industrial Co., Ltd.) Can be mentioned. When the said radiation sensitive resin composition contains surfactant, as an upper limit of content of surfactant, 2 mass parts is preferable with respect to 100 mass parts of [A] polymers.

[Alicyclic skeleton-containing compound]
The alicyclic skeleton-containing compound has an effect of improving dry etching resistance, pattern shape, adhesion to the substrate, etc., when the radiation-sensitive resin composition contains the alicyclic skeleton-containing compound. is there.

Examples of the alicyclic skeleton-containing compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl;
Deoxycholic acid esters such as t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid;
Lithocholic acid esters such as t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid;
3- [2-Hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane, and the like. When the said radiation sensitive resin composition contains an alicyclic skeleton containing compound, as an upper limit of content of an alicyclic skeleton containing compound, 5 mass parts is preferable with respect to 100 mass parts of [A] polymers. .

[Sensitizer]
The sensitizer exhibits an action of increasing the amount of acid produced from the acid generator [B] when the radiation-sensitive resin composition contains a sensitizer, and the like. The effect of improving the “apparent sensitivity” of the resin composition is exhibited.

  Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like. When the said radiation sensitive resin composition contains a sensitizer, as an upper limit of content of a sensitizer, 2 mass parts is preferable with respect to 100 mass parts of [A] polymers.

<Method for preparing radiation-sensitive resin composition>
In the radiation sensitive resin composition, for example, [A] polymer, [B] acid generator, [C] solvent, and [D] acid diffusion controller contained as necessary are mixed at a predetermined ratio. Can be prepared. The radiation-sensitive resin composition is preferably filtered after mixing with, for example, a filter having a pore size of about 0.2 μm. As a minimum of solid concentration of the radiation sensitive resin composition, 0.1 mass% is preferred, 0.5 mass% is more preferred, and 1 mass% is still more preferred. As an upper limit of the said solid content concentration, 50 mass% is preferable, 30 mass% is more preferable, and 10 mass% is further more preferable.

<Resist pattern formation method>
The resist pattern forming method includes a step of forming a resist film (hereinafter also referred to as “resist film forming step”), a step of exposing the resist film (hereinafter also referred to as “exposure step”), and the exposed resist. A step of developing the film (hereinafter also referred to as “developing step”). In the resist pattern forming method, the resist film is formed from the radiation-sensitive resin composition.

  According to the resist pattern forming method, since the radiation sensitive resin composition described above is used, a resist pattern can be formed while exhibiting excellent PEB temperature dependency. Hereinafter, each step will be described.

[Resist film forming step]
In this step, a resist film is formed using the radiation sensitive resin composition. Examples of the substrate on which the resist film is formed include conventionally known ones such as a silicon wafer, silicon dioxide, and a wafer coated with aluminum. Further, for example, an organic or inorganic antireflection film disclosed in Japanese Patent Publication No. 6-12452, Japanese Patent Application Laid-Open No. 59-93448, or the like may be formed on the substrate. Examples of the coating method include spin coating (spin coating), cast coating, and roll coating. After application, pre-baking (PB) may be performed as needed to volatilize the solvent in the coating film. As a minimum of the temperature of PB, 60 degreeC is preferable and 80 degreeC is more preferable. As an upper limit of the said temperature, 140 degreeC is preferable and 120 degreeC is more preferable. The lower limit of the PB time is preferably 5 seconds, and more preferably 10 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. As a minimum of the average thickness of the resist film formed, 10 nm is preferable and 20 nm is more preferable. As an upper limit of the average thickness, 1,000 nm is preferable, and 500 nm is more preferable.

  In the case of performing immersion exposure, when the radiation sensitive resin composition does not contain a water-repellent polymer additive such as [E] polymer, the immersion liquid is formed on the resist film formed as described above. In order to avoid direct contact between the resist film and the resist film, an immersion protective film insoluble in the immersion liquid may be provided. As the protective film for immersion, a solvent-removable protective film that peels off with a solvent before the developing process (see JP 2006-227632 A), a developer-removable protective film that peels off simultaneously with development in the developing process (International Publication) No. 2005/069096 and International Publication No. 2006/035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer peeling type immersion protective film.

[Exposure process]
In this step, exposure is performed by irradiating the resist film formed in the resist film forming step with exposure light through a photomask (in some cases, through an immersion medium such as water). Examples of exposure light include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays, and γ rays, and charged particle beams such as electron beams and α rays, depending on the size of the target pattern. Is mentioned. Among these, deep ultraviolet rays, EUV and electron beams are preferable, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), EUV and electron beams are more preferable, ArF excimer laser light, EUV and electron beams are more preferable. More preferred is ArF excimer laser light.

  When the exposure is performed by immersion exposure, examples of the immersion liquid to be used include water and a fluorine-based inert liquid. The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient that is as small as possible so as to minimize distortion of the optical image projected onto the film. In the case of excimer laser light (wavelength 193 nm), it is preferable to use water from the viewpoints of availability and easy handling in addition to the above-described viewpoints. When water is used, an additive that reduces the surface tension of water and increases the surface activity may be added in a small proportion. This additive is preferably one that does not dissolve the resist film on the wafer and can ignore the influence on the optical coating on the lower surface of the lens. The water used is preferably distilled water.

  After the above exposure, post-exposure baking is performed to promote dissociation of the acid-dissociable group of the [A] polymer by the acid generated from the [B] acid generator by exposure at the exposed portion of the resist film. It is preferable to make it. This PEB can increase the difference in solubility in the developer between the exposed portion and the unexposed portion. As a minimum of the temperature of PEB, 50 degreeC is preferable and 80 degreeC is more preferable. As an upper limit of the said temperature, 180 degreeC is preferable and 130 degreeC is more preferable. The lower limit of the PEB time is preferably 5 seconds, and more preferably 10 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds.

[Development process]
In this step, the resist film exposed in the exposure step is developed. Thereby, a predetermined resist pattern can be formed. After development, it is common to wash with a rinse solution such as water or alcohol and then dry. The development method in the development step may be alkali development or organic solvent development.

  In the case of alkaline development, examples of the developer used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n- Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1 , 5-diazabicyclo- [4.3.0] -5-nonene, and an alkaline aqueous solution in which at least one alkaline compound is dissolved. Among these, a TMAH aqueous solution is preferable, and a 2.38 mass% TMAH aqueous solution is more preferable.

  In the case of organic solvent development, examples of the developer include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, and other organic solvents, and solvents containing the above organic solvents. As said organic solvent, 1 type (s) or 2 or more types of the solvent enumerated as [C] solvent of the above-mentioned radiation sensitive resin composition are mentioned, for example. Among these, ester solvents and ketone solvents are preferable. As the ester solvent, an acetate solvent is preferable, and n-butyl acetate is more preferable. As the ketone solvent, a chain ketone is preferable, and 2-heptanone is more preferable. As a minimum of content of the organic solvent in a developing solution, 80 mass% is preferred, 90 mass% is more preferred, 95 mass% is still more preferred, and 99 mass% is especially preferred. Examples of components other than the organic solvent in the developer include water and silicone oil.

  As a developing method, organic solvent development is preferable.

  In addition, as a developing method, for example, a method of immersing the substrate in a tank filled with the developer for a predetermined time (dip method), a method of developing the developer by raising the developer by surface tension on the surface of the substrate and standing for a predetermined time ( Paddle method), a method of spraying a developer on the surface of a substrate (spray method), a method of continuously applying a developer while scanning a developer coating nozzle on a substrate rotating at a constant speed (dynamic dispensing) Law).

<Polymer>
The said polymer is a polymer which has a structural unit (I-1). Since the said polymer has the above-mentioned property, it can be used suitably as a polymer component of the said radiation sensitive resin composition, and the radiation sensitive resin composition containing this is excellent in PEB temperature dependency.

<Compound>
The compound is compound (i-1). Since the said compound has the above-mentioned property, it can be used suitably as a raw material monomer of the said polymer.

  The polymer and the compound are described in the above section [A] Polymer.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Each measurement in the examples was performed by the following methods.

[Mw, Mn and Mw / Mn]
Mw and Mn use Tosoh's GPC columns (G2000HXL: 2, G3000HXL: 1, G4000HXL: 1), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, sample concentration: 1.0 mass% Sample injection amount: 100 μL, column temperature: 40 ° C., detector: measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of a differential refractometer. The degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

[ ¹³ C-NMR analysis]
Using “JNM-ECX400” manufactured by JEOL Ltd., deuterated chloroform was used as a measurement solvent, and the content ratio (mol%) of each structural unit in each polymer was analyzed.

<Synthesis of compounds>
[Example 1] (Synthesis of Compound (M-1))
To a 500 mL round bottom flask, 12.71 g (79 mmol) of (m-1), 13.86 g (175 mmol) of pyridine, 0.97 g (7.9 mmol) of dimethylaminopyridine and 140 mL of methylene chloride were added and stirring was started at 0 ° C. . Thereto, 10.05 g (87.4 mmol) of thiophosgene was slowly added dropwise. After completion of the dropwise addition, the mixture was stirred at room temperature for 2 hours, and 1M aqueous hydrochloric acid solution was added to extract the organic layer. The obtained organic layer was washed twice with water and then dried over anhydrous sodium sulfate. After the solvent was distilled off, 9.41 g (yield 59%) of (M-1) was obtained by purification by column chromatography.

[Examples 2 to 21] (Synthesis of compounds (M-2) to (M-21))
The precursors were appropriately selected, and the same operations as in Example 1 were performed to synthesize compounds represented by the following formulas (M-2) to (M-21).

  Compounds (M-1) to (M-21) give the structural unit (I).

<Synthesis of [A] polymer and [E] polymer>
The monomers used in the synthesis of each polymer in each example and comparative synthesis example are shown below.

  Compounds (M′-1) to (M′-4) give structural unit (II), and compounds (M′-5) to (M′-10) and (M′-12) represent structural unit (III). Compound (M′-11) gives structural unit (IV) and Compound (M′-14) gives structural unit (Ea).

[[A] Synthesis of polymer]
[Example 22] (Synthesis of polymer (A-1))
9.47 g (50 mol%) of compound (M′-1), 8.58 g (40 mol%) of compound (M′-6) and 1.95 g (10 mol%) of compound (M-1) were converted to 2-butanone. It melt | dissolved in 40g and added AIBN 0.79g (5 mol% with respect to all the monomers) as an initiator, and prepared the monomer solution. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, and then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The polymerization solution cooled in 400 g of methanol was added, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 80 g of methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-1) (15.7 g, yield 79). %). Mw of the polymer (A-1) was 7,400, and Mw / Mn was 1.54. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M′-1), (M′-6) and (M-1) was 50.1 mol% and 40.1 mol%, respectively. And 9.8 mol%.

[Examples 23 to 53 and Comparative Synthesis Examples 1 to 3] (Synthesis of Polymers (A-2) to (A-32) and (CA-1) to (CA-3))
Polymers (A-2) to (A-32) and (CA) were obtained by carrying out the same operations as in Example 22 except that the types and amounts of monomers shown in Table 1 or Table 2 were used. -1) to (CA-3) were synthesized.

  In Table 2 above, “-” indicates that the corresponding component was not used.

[[E] Synthesis of polymer]
[Synthesis Example 1] (Synthesis of polymer (E-1))
Compound (M′-2) 71.67 g (70 mol%) and compound (M′-14) 28.33 g (30 mol%) were dissolved in 100 g of 2-butanone, and dimethyl 2,2 ′ as an initiator was dissolved. A monomer solution was prepared by dissolving 6.47 g of azobisisobutyrate (5 mol% with respect to the total monomer). Next, a 1,000 mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, and then heated to 80 ° C. with stirring, and the monomer solution prepared above was added dropwise over 3 hours using a dropping funnel. . The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The reaction solution was transferred to a 2 L separatory funnel, and then the polymerization solution was uniformly diluted with 150 g of n-hexane, and 600 g of methanol was added and mixed. Next, 30 g of distilled water was added, and the mixture was further stirred and allowed to stand for 30 minutes. Thereafter, the lower layer was recovered to obtain a propylene glycol monomethyl ether acetate solution containing the polymer (E-1) as a solid content (yield 60%). Mw of the polymer (E-1) was 7,200, and Mw / Mn was 2.00. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M′-2) and (M′-4) was 71.1 mol% and 28.9 mol%, respectively.

<Preparation of radiation-sensitive resin composition>
[B] acid generator, [C] solvent, [D] acid diffusion controller and [F] acceleration of uneven distribution used in the preparation of the radiation sensitive resin compositions of Examples 54 to 89 and Comparative Examples 1 to 3 below. The agent is shown below.

[[B] acid generator]
Each structural formula is shown below.
B-1: Triphenylsulfonium 2- (adamantan-1-ylcarbonyloxy) -1,1,3,3,3-pentafluoropropane-1-sulfonate B-2: Triphenylsulfonium norbornane sultone-2-yloxy Carbonyl difluoromethanesulfonate B-3: Triphenylsulfonium 3- (piperidin-1-ylsulfonyl) -1,1,2,2,3,3-hexafluoropropane-1-sulfonate B-4: Triphenylsulfonium adamantane- 1-yloxycarbonyldifluoromethanesulfonate

[[C] solvent]
C-1: Propylene glycol monomethyl ether acetate C-2: Cyclohexanone

[[D] acid diffusion controller]
Each structural formula is shown below.
D-1: Triphenylsulfonium salicylate D-2: Triphenylsulfonium 10-camphorsulfonate D-3: N- (n-undecan-1-ylcarbonyloxyethyl) morpholine D-4: 2,6-di- i-propylaniline D-5: tri-n-pentylamine

[[F] uneven distribution promoter]
F-1: γ-butyrolactone

[Preparation of radiation-sensitive resin composition for ArF exposure]
[Example 54]
[A] 100 parts by mass of (A-1) as a polymer, [B] 8.5 parts by mass of (B-1) as an acid generator, [C] 2,240 parts by mass of (C-1) as a solvent Part and (C-2) 960 parts by weight, [D] 2.3 parts by weight (D-1) as an acid diffusion controller, 3 parts by weight (E-1) as a polymer [E] and [F] A radiation sensitive resin composition (J-1) was prepared by blending 30 parts by mass of (F-1) as an uneven distribution accelerator and filtering with a membrane filter having a pore size of 0.2 μm.

[Examples 55-89 and Comparative Examples 1-3]
Each radiation-sensitive resin composition was prepared in the same manner as in Example 54 except that the components of the types and blending amounts shown in Table 3 or 4 below were used.

<Formation of resist pattern>
On the surface of a 12-inch silicon wafer, using a spin coater (“CLEAN TRACK ACT12” manufactured by Tokyo Electron Co., Ltd.), a composition for forming a lower antireflection film (“ARC66” manufactured by Brewer Science Inc.) was applied. By heating at 60 ° C. for 60 seconds, a lower antireflection film having an average thickness of 105 nm was formed. On the lower antireflection film, each of the prepared radiation sensitive resin compositions was applied using the spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 90 nm. Next, this resist film was exposed using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON) under the best focus conditions under NA = 1.3 and dipole optical conditions. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, development with an organic solvent was performed using n-butyl acetate as an organic solvent developer, followed by drying to form a negative resist pattern. At this time, a resist pattern having a hole size with a hole pattern diameter of 0.060 μm and a pitch of 0.225 μm was formed.

<Evaluation>
About the formed resist pattern, each radiation sensitive resin composition was evaluated by measuring according to the following method. A scanning electron microscope (Hitachi High-Technologies “CG-4100”) was used for measuring the resist pattern.

[PEB temperature dependence]
Resist patterns were formed by performing the same operations as the resist pattern formation except that the PEB temperatures were changed to 89 ° C., 90 ° C., and 91 ° C., respectively. The diameter of the hole pattern at each PEB temperature was measured using a scanning electron microscope. The horizontal axis is the PEB temperature (° C) and the vertical axis is the hole pattern diameter (nm). The measured values are plotted, and the slope of the approximate straight line calculated by the least square method is obtained. (Nm / ° C.). It shows that it is excellent in PEB temperature dependence, so that this inclination is small. The PEB temperature dependency was judged as “good” when it was 6.00 nm / ° C. or less, and “bad” when it exceeded 6.00 nm / ° C.

  As is clear from the results in Table 5, in Examples, PEB temperature dependency was good in organic solvent development, whereas in Comparative Examples, it was poor.

  According to the radiation sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern can be formed while exhibiting excellent PEB temperature dependency. The polymer of this invention can be used suitably as a polymer component of the said radiation sensitive resin composition. The compound of the present invention can be suitably used as a monomer for the polymer. Accordingly, these can be suitably used for manufacturing semiconductor devices that are expected to be further miniaturized in the future.

Claims (7)

A polymer having a first structural unit containing a group represented by the following formula (1):
A radiation-sensitive resin composition comprising a radiation-sensitive acid generator and a solvent.

(In Formula (1), R ¹ is a substituted or unsubstituted trivalent hydrocarbon group having 1 to 20 carbon atoms. * Is a group represented by Formula (1) in the first structural unit. The site | part couple | bonded with other parts is shown.) The radiation sensitive resin composition according to claim 1, wherein the first structural unit is represented by the following formula (2).

(In Formula (2), ^Ra is a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹ has the same meaning as the above formula (1).)   The radiation sensitive resin composition of Claim 1 or Claim 2 in which the said polymer further has the 2nd structural unit containing an acid dissociable group.   The radiation-sensitive resin composition according to claim 1, 2 or 3, wherein the polymer further has a third structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. Forming a resist film;
A step of exposing the resist film, and a step of developing the exposed resist film,
The resist pattern formation method which forms the said resist film with the radiation sensitive resin composition of any one of Claims 1-4. The polymer which has a structural unit represented by following formula (2).

(In Formula (2), ^Ra is a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹ is a substituted or unsubstituted trivalent hydrocarbon group having 1 to 20 carbon atoms. A compound represented by the following formula (3).

(In Formula (3), ^Ra is a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹ is a substituted or unsubstituted trivalent hydrocarbon group having 1 to 20 carbon atoms.