JP2018005064A - 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 LWR performance, CDU performance, resolution, rectangularity of cross-sectional shape, depth of focus, MEEF performance and film shrinkage inhibitory property. The present invention has a radiation-sensitive resin composition containing a first polymer having a first structural unit containing a group represented by the following formula (1), a radiation-sensitive acid generator, and a solvent. It is a thing. In the following formula (1), R1, R2 and R3 are independently monovalent organic groups having 1 to 20 carbon atoms. R4 and R5 are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. Two or more of R1 to R5 and L may be combined with each other to represent a ring structure having 3 to 20 ring members together with an atomic chain to which they are bonded. It is preferable that R4 and R5 in the above formula (1) are organic groups, and these organic groups are substituted or unsubstituted monovalent hydrocarbon groups having 1 to 16 carbon atoms. [Selection diagram] 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 to form a resist pattern on the substrate.

  Such a radiation sensitive resin composition is not only excellent in resolution and the like, but also excellent in LWR (Line Width Roughness) performance in line and space pattern formation and the rectangular shape of the cross-sectional shape of the resist pattern, In addition to being excellent in CDU (Critical Dimension Uniformity) performance in hole pattern formation and the like, it is also required to be excellent in depth of focus and MEEF (Mask Error Enhancement Factor) performance, and to obtain a highly accurate pattern with high yield. In response to this requirement, various structures of the polymer contained in the radiation-sensitive resin composition have been studied. By having a lactone structure such as a butyrolactone structure or a norbornane lactone structure, the resist pattern can be adhered to the substrate. It is known that these properties can be improved while improving the performance (see JP-A-11-212265, JP-A-2003-5375 and JP-A-2008-83370).

  However, at present, when the miniaturization of the resist pattern has progressed to a level of 45 nm or less, the required level of the performance is further increased, and the conventional radiation-sensitive resin composition satisfies these requirements. I can't make it happen. Recently, it is required that the shrinkage of the resist film during post-exposure heating (post exposure bake (PEB)) be small, and as a result, the above-described various resist performances are required to be further improved.

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

  The present invention has been made on the basis of the circumstances as described above, and its purpose is to provide an excellent feeling of LWR performance, CDU performance, resolution, rectangular shape of the cross-sectional shape, depth of focus, MEEF performance, and membrane shrinkage suppression. A radiation resin composition, a resist pattern forming method, a polymer, and a compound are provided.

（式（１）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立して、炭素数１〜２０の１価の有機基である。Ｒ^４及びＲ^５は、それぞれ独立して、水素原子又は炭素数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〜Ｒ^５及びＬのうちの２つ以上が互いに合わせられこれらが結合する原子鎖と共に環員数３〜２０の環構造を表してもよい。＊は、上記構造単位（Ｉ）における上記基（Ｉ）以外の部分との結合部位を示す。） 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 (I)”). A first polymer (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 “[A] polymer”). A radiation-sensitive resin composition containing "[C] solvent").

(In formula (1), R ¹ , R ² and R ³ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a hydrogen 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, and two or more of R ^{1 to} R ⁵ and L are mutually bonded. And may represent a ring structure having 3 to 20 ring members together with an atomic chain to which these are bonded, * indicates a bonding site with a portion other than the group (I) in the structural unit (I).

  Another invention made to solve the above problems is a process of coating the radiation-sensitive resin composition on one surface of the substrate, a process of exposing a resist film obtained by the coating process, And a step of developing the exposed resist film.

  Yet another invention made to solve the above problems is a polymer having a structural unit containing the group (I).

（式（ｉ）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立して、炭素数１〜２０の１価の有機基である。Ｒ^４及びＲ^５は、それぞれ独立して、水素原子又は炭素数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〜Ｒ^５及びＬのうちの２つ以上が互いに合わせられこれらが結合する原子鎖と共に環員数３〜２０の環構造を表してもよい。Ｒ^１０は、重合性炭素−炭素二重結合を含む１価の基である。 Yet another invention made to solve the above problems is a compound represented by the following formula (i) (hereinafter also referred to as “compound (i)”).

(In formula (i), R ¹ , R ² and R ³ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a hydrogen 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, and two or more of R ^{1 to} R ⁵ and L are mutually bonded. Together with the atomic chain to which they are bonded, they may represent a ring structure having 3 to 20 ring members, and R ¹⁰ is a monovalent group containing a polymerizable carbon-carbon double bond.

  Here, the “organic group” refers to a group containing at least one carbon atom. The “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and 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. “Number of ring members” means the number of atoms constituting the ring of the alicyclic structure, aromatic ring structure, aliphatic heterocyclic structure and aromatic heterocyclic structure, and in the case of polycyclic, the number of atoms constituting this polycyclic ring Say.

  According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, LWR and CDU are small, resolution is high, and the cross-sectional shape is rectangular while exhibiting excellent depth of focus, MEEF performance, and film shrinkage suppression. It is possible to form a resist pattern that is excellent in resistance. 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 has, as a suitable component, a polymer having a mass content of fluorine atoms larger than that of [D] acid diffusion controller and / or [E] [A] polymer (hereinafter referred to as “[D] May also contain other optional components as long as the effects of the present invention are not impaired. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I). In the radiation-sensitive resin composition, the [A] polymer has the structural unit (I), so that LWR performance, CDU performance, resolution, rectangularity of the cross-sectional shape, depth of focus, MEEF performance, and suppression of film shrinkage. Excellent in properties (hereinafter also referred to as “LWR performance etc.”). 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, the structural unit (I) of the [A] polymer has two acetal structures that are decomposed by the action of an acid to generate a hydroxy group. Since this structural unit (I) is easily decomposed by the action of an acid and two hydroxy groups are generated, the contrast between the exposed portion and the unexposed portion can be further increased. Moreover, since the structural unit (I) contains many oxygen atoms and has a high polarity, the diffusion length of the acid generated from the [B] acid generator can be shortened appropriately. As a result, the LWR performance, the CDU performance, the resolution, the cross-sectional rectangularity, the focal depth, and the MEEF performance of the radiation sensitive resin composition can be improved. In addition, in the structural unit (I) of the exposed portion, two hydroxy groups are generated by the action of an acid. Therefore, the resist film during PEB is formed by a hydrogen bond between the hydroxy groups of the polymer chain of the [A] polymer. It is considered that the shrinkage can be suppressed, and the radiation-sensitive resin composition is excellent in the film shrinkage inhibiting property.

  [A] The polymer is a structural unit other than the structural unit (I) in addition to the structural unit (I), and includes a structural unit containing an acid dissociable group (hereinafter also referred to as “structural unit (II)”) and It is preferable to have a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure or a combination thereof (hereinafter also referred to as “structural unit (III)”), and other than structural units (I) to (III) It may have a structural unit of [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 (I). The group (I) is a group represented by the following formula (1).

Above formula ^(1), R 1, ^{R 2} and ^{R 3} are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a hydrogen 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. Two or more of R ^{1 to} R ⁵ and L may be combined with each other to represent a ring structure having 3 to 20 ring members together with an atomic chain to which these are bonded. * Indicates a binding site with a moiety other than the group (I) in the structural unit (I).

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^{1 to} R ⁵ include a monovalent hydrocarbon group having 1 to 20 carbon atoms and a divalent hydrocarbon between carbon-carbon of the hydrocarbon group. Examples include a group (α) containing a heteroatom-containing group, a group obtained by substituting part or all of the hydrogen atoms of the hydrocarbon group and the group (α) 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 alicyclic saturated hydrocarbon groups such as a cyclopentyl group and a cyclohexyl group;
Monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopentenyl group and cyclohexenyl group;
Polycyclic alicyclic saturated hydrocarbon groups such as norbornyl group, adamantyl group and tricyclodecyl group;
Examples thereof include polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group and a 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 hydrocarbon group. Of these, -O- is preferred.

  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). Among these, a fluorine atom is preferable.

R ¹ , R ² and R ³ are preferably groups in which the bonding site to the oxygen atom is a carbon atom. R ¹ , R ² and R ³ are preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 16 carbon atoms and a lactone ring group, and a substituted or unsubstituted monovalent carbon group having 1 to 16 carbon atoms. A hydrogen group is more preferable, an alkyl group, an aryl group, and a fluorinated alkyl group are more preferable, and a methyl group, an ethyl group, an isopropyl group, a phenyl group, and a trifluoroethyl group are further preferable.

In addition, as R ¹ , R ² and R ³ , a group represented by the following formula (a) is preferable from the viewpoint of ease of synthesis of the monomer that gives the structural unit (I).

In the formula (a), R ⁶ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 15 carbon atoms. ** represents a site bonded to the oxygen atom adjacent to the carbon atom to which R ⁴ is bonded in the above formula (1) or the oxygen atom adjacent to the carbon atom to which R ⁵ is bonded.

Examples of the monovalent hydrocarbon group having 1 to 15 carbon atoms represented by R ⁶ include those having 1 to 15 carbon atoms among the monovalent hydrocarbon groups exemplified as the above R ^{1 to} R ^5. It is done.

R ⁴ and R ⁵ are preferably a monovalent organic group having 1 to 20 carbon atoms, and more preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 16 carbon atoms.

Examples of the divalent organic group having 1 to 20 carbon atoms represented by L include a group in which one hydrogen atom is removed from the groups exemplified as the monovalent organic group of R ^{1 to} R ⁵ above. .

  L is preferably a divalent organic group, more preferably a divalent hydrocarbon group, and still more preferably an alkanediyl group.

Examples of the ring structure having 3 to 20 carbon atoms constituted by two or more of the groups R ^{1 to} R ⁵ and L and the carbon atom to which they are bonded include a cyclopropane structure, a cyclobutane structure, and a cyclopentane. Monocyclic saturated alicyclic structures such as structures, cyclohexane structures, cycloheptane structures, cyclooctane structures;
Polycyclic saturated alicyclic structures such as norbornane structure, adamantane structure, tricyclodecane structure and tetracyclododecane structure;
Monocyclic aromatic carbocyclic structures such as indene structures;
Polycyclic aromatic carbocyclic structures such as fluorene structures;
Monocyclic aliphatic heterocyclic structures such as oxacyclopentane structure and oxacyclohexane structure;
Examples thereof include polycyclic aliphatic heterocyclic structures such as an oxanorbornane structure and an oxaadamantane structure.

Examples of the ring structure formed by R ¹ and R ² include an aliphatic heterocyclic structure containing two oxygen atoms such as a dioxacyclohexane structure and a dioxacycloheptane structure.

Examples of the ring structure constituted by R ⁴ and R ⁵ include an alicyclic structure such as a cycloalkane structure such as a cyclohexane structure and a cycloheptane structure.

Examples of the ring structure formed by R ¹ , R ^4, R ^2, and R ⁵ include an aliphatic heterocyclic structure containing one oxygen atom such as an oxacyclopentane structure and an oxacyclohexane structure.

L and R ³ preferably represent a ring structure having 5 to 20 ring members configured together with an atomic chain to which they are combined and bonded to each other.

Examples of the ring structure composed of L and R ³ include an aliphatic heterocyclic structure containing two oxygen atoms such as a dioxacyclohexane structure and a dioxacycloheptane structure.

  Examples of the group (I) include groups represented by the following formulas (1-1) to (1-12) (hereinafter also referred to as “groups (I-1) to (I-12)”). .

  In the above formulas (1-1) to (1-12), * has the same meaning as the above formula (1).

  Of these, groups (I-1) to (I-12) are preferred.

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

In the above formula (A), Z is the above group (I). Y is a single bond or a C1-C20 divalent organic group. R ⁷ and R ⁸ are each independently a hydrogen atom or a methyl group. R ⁹ is a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms.

  Y is preferably a single bond.

R ⁷ and R ⁸ are preferably a hydrogen atom from the viewpoint of the copolymerizability of the monomer giving the structural unit (I).

R ⁹ is preferably a hydrogen atom, a methyl group, or a carbonyloxy hydrocarbon group, and more preferably a carbonyloxy group in which a methyl group and an acid dissociable group are bonded.

  Examples of the structural unit (I) include structural units represented by the following formulas (A-1) to (A-3) (hereinafter also referred to as “structural units (I-1) to (I-3)”), and the like. Is mentioned.

In the above formulas (A-1), (A-2) and (A-3), Z, R ⁷ , R ⁸ and R ⁹ have the same meanings as the above formula (A).
In the above formula (A-2), R ^A is a monovalent organic group having 1 to 19 carbon atoms.
In the above formula (A-3), R ^B is a monovalent organic group having 1 to 10 carbon atoms. p is an integer of 0-4. When p is 2 or more, the plurality of R ^B may be the same or different.

Examples of the monovalent organic group having 1 to 19 carbon atoms represented by ^RA include those having 1 to 19 carbon atoms among the monovalent organic groups represented by R ^{1 to} R ⁵ described above. . Examples of the monovalent organic group having 1 to 10 carbon atoms represented by R ^B include those having 1 to 10 carbon atoms among the monovalent organic groups represented by R ^{1 to} R ⁵ described above. .

  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, 3 mol% is more preferable, 5 mol% is further more preferable, 10 mol % Is particularly preferred. As an upper limit of the content rate of structural unit (I), 80 mol% is preferable, 60 mol% is more preferable, 50 mol% is further more preferable, 30 mol% is especially preferable. By making the content rate of structural unit (I) into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved more.

  The compound giving the structural unit (I) contains the group (I). Examples of the compound that gives the structural unit (I) include a compound (i) represented by the following formula (i).

In the above formula ^{(i), R 1, R} 2 and ^{R 3} are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a hydrogen 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. Two or more of R ^{1 to} R ⁵ and L may be combined with each other to represent a ring structure having 3 to 20 ring members together with an atomic chain to which these are bonded. R ¹⁰ is a monovalent group containing a polymerizable carbon-carbon double bond.

Examples of the group containing a polymerizable carbon-carbon double bond in the monovalent group of R ¹⁰ include a (meth) acryloyl group, a vinyl group, and a styryl group.

  Examples of the compound (i) include compounds represented by the following formulas (i1) to (i12) (hereinafter also referred to as “compounds (i1) to (i12)”).

In the above formulas (i1) to (i9), (i11) and (i12), R ¹¹ is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  Of these, compounds (i1) to (i12) are preferred.

In the compound (i), for example, a divalent organic group having 1 to 20 carbon atoms of L in the above formula (i) and a methyl group of R ³ are combined with each other, and R ¹ and R ² are R ¹² In the case of the compound (i ′), it can be synthesized simply and with high yield according to the following scheme.

In the above scheme, L ′ is a trivalent organic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ¹⁰ is a monovalent group containing a polymerizable carbon-carbon double bond. R < ¹² > is respectively independently a C1-C20 monovalent organic group.

A dihydroxy compound having a polymerizable carbon-carbon double bond represented by the above formula (ia), an α-diketo compound represented by the above formula (ib), and HC (OR ¹² ) ₃ The compound (i ′) can be obtained by reacting the orthoformate produced in a solvent such as methanol in the presence of a catalyst such as p-toluenesulfonic acid.

  The compound (i) can be isolated by appropriately purifying the obtained product by column chromatography, recrystallization, distillation or the like.

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

[Structural unit (II)]
The structural unit (II) is a structural unit other than the structural unit (I) and includes an acid dissociable group. The “acid-dissociable group” refers to a group that replaces a hydrogen atom such as a carboxy group or a hydroxy group and dissociates by the action of an acid. In the radiation-sensitive resin composition, since the [A] polymer has the structural unit (II) in addition to the structural unit (I), the sensitivity is further increased, and as a result, the LWR performance and the like can be further improved. .

  Examples of the structural unit (II) include a structural unit represented by the following formula (2) (hereinafter also referred to as “structural unit (II-1)”) and a structural unit containing an acetal structure (hereinafter referred to as “structural unit (II)”. -2) "). [A] The polymer may have one or more structural units (II-1) and (II-2). [A] The polymer may have both the structural unit (II-1) and the structural unit (II-2). Hereinafter, the structural unit (II-1) and the structural unit (II-2) will be described.

(Structural unit (II-1))
The structural unit (II-1) is a structural unit represented by the following formula (2). The group represented by —CR ¹⁵ R ¹⁶ R ¹⁷ in the above formula (2) is an acid dissociable group.

In the formula (2), R ¹⁴ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁵ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹⁶ and R ¹⁷ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or 3 to 3 carbon atoms composed of these groups together with the carbon atom to which they are bonded. 20 alicyclic structures are represented.

R ¹⁴ is preferably a hydrogen atom and a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (II-1).

The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹⁵ , R ¹⁶ and R ¹⁷ is, for example, a monovalent hydrocarbon having 1 to 20 carbon atoms exemplified as R ^{1 to} R ^{5 in} the above formula (1). And the same groups as the hydrocarbon group. Examples of the alicyclic structure having 3 to 20 carbon atoms configured together with the carbon atom to which the groups of R ¹⁶ and R ¹⁷ are combined with each other include, for example, R ^{1 to} R ⁵ and L of the above formula (1) Among the ring structures composed of two or more combined together and an atomic chain to which they are bonded, those having an alicyclic structure are exemplified.

  As the structural unit (II-1), structural units represented by the following formulas (2-1) to (2-5) (hereinafter referred to as “structural units (II-1-1) to (II-1-5)”) Are also preferred).

In the above formulas (2-1) to (2-5), R ^{14 to} R ¹⁷ have the same meaning as the above formula (2). i and j are each independently an integer of 1 to 4.

  Examples of the structural unit (II) and the structural units (II-1-1) to (II-1-5) include structural units represented by the following formulas.

In said formula, R < ¹⁴ > is synonymous with the said Formula (2).

  As the structural unit (II), the structural unit (II-1-1) is preferable, and a structural unit derived from 1-alkyl-1-cyclopentyl (meth) acrylate and 2-alkyl-2-tetracyclodecanyl (meth) A structural unit derived from acrylate is more preferred.

(Structural unit (II-2))
The structural unit (II-2) is a structural unit containing an acetal structure. Examples of the group containing an acetal structure include a group represented by the following formula (X) (hereinafter also referred to as “group (X)”). The group (X) is decomposed by the action of an acid to give * —OH, R ^X R ^Y ═O and R ^Z OH. In the group (X), —C (R ^X ) (R ^Y ) (OR ^Z ) is an acid dissociable group.

In the above formula (X), R ^X and R ^Y are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^Z is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^W is a divalent hydrocarbon group of a single bond or a C 1-20. Two or more of R ^X , R ^Y , R ^Z and R ^W may be combined with each other to form a ring structure having 3 to 20 ring members together with the carbon atom or atomic chain to which they are bonded. * Represents a binding site with a moiety other than the group (X) in the structural unit (II-2).

The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^X , R ^Y and R ^Z is, for example, a monovalent hydrocarbon having 1 to 20 carbon atoms exemplified as R ^{1 to} R ^{5 in} the above formula (1). And the same groups as the hydrocarbon group.

R ^X and R ^Y are preferably a hydrogen atom and a chain hydrocarbon group, more preferably a hydrogen atom and an alkyl group, and still more preferably a hydrogen atom and a methyl group. R ^Z is preferably a chain hydrocarbon group, more preferably an alkyl group, and particularly preferably a methyl group.

The R ^W, a single bond or a chain hydrocarbon group, more preferably a chain-like hydrocarbon group, more preferably an alkanediyl group, methylene bridge are particularly preferred.

Examples of the ring structure having 3 to 20 ring members formed by two or more of R ^X , R ^Y , R ^Z and R ^W include 1,3-dioxacyclo such as 1,3-dioxacyclopentane structure. Examples include alkane structures.

  The group (X) is preferably a group containing a cyclic acetal structure, and more preferably a group containing a 2,2-dimethyl-1,3-dioxacyclopentane structure.

  Examples of the structural unit (I-2) include a structural unit represented by the following formula (3).

In said formula (3), ^RC is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L ¹ is a single bond or a divalent organic group having 1 to 20 carbon atoms. T is the group (X). n is an integer of 1 to 3. When n is 2 or more, the plurality of T may be the same or different.

R ^C is more preferably a hydrogen atom and a methyl group, and even more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (I-2).

Examples of the divalent organic group having 1 to 20 carbon atoms represented by L ^1, for example, a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms, -CO-, and the like. Examples of the substituent of the hydrocarbon group include a hydroxy group, a halogen atom, an alkoxy group, and a cyano group.

L ¹ is preferably a single bond or —CO—, more preferably —CO—.

  As n, 1 and 2 are preferable and 1 is more preferable.

  As the structural unit (I-2), a structural unit containing a 2,2-dimethyl-1,3-dioxacyclopentan-5-yl group is 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%, and 20 mol with respect to all the structural units constituting the polymer. % Is more preferable, and 25 mol% is more preferable. As an upper limit of the said content rate, 80 mol% is preferable, 60 mol% is more preferable, and 40 mol% is further more preferable. By making the content rate of structural unit (II) into the said range, the sensitivity of the said radiation sensitive resin composition further improves, As a result, LWR performance etc. can be improved further.

[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 further adjusted, and as a result, the LWR performance and the like of the radiation-sensitive resin composition are further improved. be able to. Moreover, the adhesiveness of the resist pattern formed from the said radiation sensitive resin composition and a board | 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 norbornane lactone structure, a structural unit containing a γ-butyrolactone structure, a structural unit containing an ethylene carbonate structure, or a structural unit containing a norbornane sultone structure.

  [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. Mole% is more preferable, and 30 mol% is 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. By making the said content rate into the said range, the LWR performance etc. of the said radiation sensitive resin composition can be improved further. In addition, the adhesion of the resist pattern to the substrate can be further improved.

[Other structural units]
[A] The polymer may have other structural units other than the structural units (I) to (III). Examples of other structural units include structural units containing a hydroxy group. Examples of the hydroxy group include alcoholic hydroxyl groups and phenolic hydroxyl groups. [A] When the polymer has a structural unit containing a phenolic hydroxyl group, the sensitivity in the case of KrF exposure, EUV exposure, electron beam exposure or the like can be further increased.

  Examples of the structural unit containing a hydroxy group include a structural unit represented by the following formula.

In the above formula, R ^L2 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  As the structural unit containing a hydroxy group, a structural unit derived from hydroxystyrene and a structural unit derived from 3-hydroxyadamantyl (meth) acrylate are preferable.

  [A] When the polymer has a structural unit containing a hydroxy group, the lower limit of the content ratio of the structural unit containing a hydroxy group is preferably 1 mol% with respect to all the structural units constituting the [A] polymer. 5 mol% is more preferable. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 30 mol% is further more preferable.

  [A] The polymer may have other structural units in addition to the structural unit containing a hydroxy group. Examples of such other structural units include a structural unit containing a carboxy group, a cyano group, a nitro group, a sulfonamide group or a combination thereof, and a structural unit containing a non-dissociable hydrocarbon group. As an upper limit of the content rate of these structural units, 20 mol% is preferable and 10 mol% is more preferable.

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

<[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 the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpropylene). Pionitrile), azo radical initiators such as 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate; benzoyl peroxide, t-butyl hydroperoxide, And peroxide radical initiators such as cumene hydroperoxide. 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, As a result, development defect inhibitory property can be improved more.

  [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: 2 "G2000HXL" from Tosoh Corporation, 1 "G3000HXL" and 1 "G4000HXL" Column temperature: 40 ° C
Elution solvent: Tetrahydrofuran (Wako Pure Chemical Industries)
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. In the radiation sensitive resin composition, the [B] acid generator is incorporated as a part of the polymer even in the form of a low molecular compound (hereinafter also referred to as “[B] acid generator” as appropriate). Either of these forms may be used.

  [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] Examples of the acid generated from the acid generator include sulfonic acid, imidic acid, amide acid, methide acid, phosphinic acid, and carboxylic acid. Of these, sulfonic acid, imidic acid, amic acid and methide acid are preferred.

  Examples of the [B] acid generator include a compound represented by the following formula (4) (hereinafter also referred to as “[B1] acid generator”).

In the above formula (4), A ⁻ represents a monovalent sulfonate anion, a monovalent imido acid anion, a monovalent amidate anion, or a monovalent methide acid anion. Z ⁺ is a monovalent radiation-sensitive onium cation.

[B1] acid generator, A in the above formula (4) ^- if the sulfonate anion (hereinafter, "[B1a]" acid generator) also called), a sulfonic acid is generated. A ^- is the case of the imide anion (hereinafter, also referred to as "[B1b] acid generator"), imide acid produced. A ^- is the case of the amide anion (hereinafter, also referred to as "[B1c] acid generator"), an amide acid occurs. A ^- is the case of the methide anion (hereinafter, also referred to as "[B1d] acid generator"), methide acid is generated.

  [B1a] Examples of the acid generator include a compound represented by the following formula (4-1) (hereinafter also referred to as “compound (4-1)”). [B1] Since the acid generator has the following structure, [A] Diffusion of acid generated by exposure in the resist film due to the interaction between the structural unit (I) and the structural unit (II) of the polymer component The length is considered to be appropriately shortened, and as a result, the LWR performance and the like of the radiation-sensitive resin composition can be further improved.

In the above formula (4-1), 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 0 to 10. However, n ^p1 + n ^p2 + n ^p3 is 1 or more and 30 or less. 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. Z ⁺ has the same ^{meaning as} in the above formula (3).

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 saturated alicyclic structures such as a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure;
Monocyclic unsaturated alicyclic structures such as cyclohexene structure, cycloheptene structure, cyclooctene structure, cyclodecene structure;
Polycyclic saturated alicyclic structures such as norbornane structure, adamantane structure, tricyclodecane structure and tetracyclododecane structure;
Examples thereof include polycyclic unsaturated alicyclic 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 aromatic heterocyclic structures having 6 or more ring members include oxygen atom-containing heterocyclic structures such as furan structures, pyran structures, and benzopyran structures;
Examples thereof include a nitrogen atom-containing heterocyclic structure such as a pyridine structure, a pyrimidine structure and an indole structure.

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. The upper limit of the number of ring members is preferably 15, more preferably 14, more preferably 13, and particularly preferably 12. By setting the number of ring members in the above range, the acid diffusion length can be further appropriately shortened, and as a result, the LWR performance and the like of the radiation-sensitive resin composition 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.

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 1 containing an alicyclic structure having 9 or more ring members. And a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members, an adamantyl group, a hydroxyadamantyl group, a norbornane lactone-yl group, a norbornane sultone-yl group, and 5-oxo-4-oxa A tricyclo [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. Among these, a carbonyloxy group, a sulfonyl group, an alkanediyl group and a divalent alicyclic saturated hydrocarbon group are preferable, a carbonyloxy group and a divalent alicyclic saturated hydrocarbon group are more preferable, and a carbonyloxy group And a norbornanediyl group are more preferable, and a carbonyloxy group is particularly preferable.

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 a minimum of ^np3 , 1 is preferable and 2 is more preferable. By setting n ^p3 to 1 or more, the strength of the acid generated from the compound (4-1) can be increased, and as a result, the LWR performance and the like of the radiation-sensitive resin composition can be further improved. The upper limit of n ^p3 is preferably 4, more preferably 3, and even more preferably 2.

The lower limit of n ^p1 + n ^p2 + n ^p3 is preferably 2 and more preferably 4. The upper limit of n ^p1 + n ^p2 + n ^p3 is preferably 20, and more preferably 10.

Examples of the monovalent radiation-sensitive onium cation represented by Z ⁺ include cations represented by the following formulas (Z-1) to (Z-3) (hereinafter referred to as “cations (Z-1) to (Z−)”. 3) ")) and the like.

In the formula (Z-1), R ^a1 , R ^a2 and R ^a3 each independently represent a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 12 carbon atoms. family hydrocarbon group, two or more are combined with each other configured ring structure of either a -OSO ₂ -R ^P or _-SO 2 -R ^Q, or their groups. R ^P and R ^Q are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or unsubstituted carbon. It is an aromatic hydrocarbon group of formula 6-12. k1, k2 and k3 are each independently an integer of 0 to 5. R ^a1 to R ^a3 and when ^{R P} and ^{R Q} are a plurality each of the plurality of ^R a1 ^{to R a3} and ^{R P} and ^{R Q} may be the same as or different from each other.

In the above formula (Z-2), R ^a4 is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms. k4 is an integer of 0 to 7. If R ^a4 is plural, the plurality of R ^a4 may be the same or different, and plural R ^a4 may represent a constructed ring aligned with each other. R ^a5 is a substituted or unsubstituted alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. k5 is an integer of 0-6. If R ^a5 is plural, the plurality of R ^a5 may be the same or different, and plural R ^a5 may represent a keyed configured ring structure. r is an integer of 0-3. R ^a6 is a single bond or a divalent organic group having 1 to 20 carbon atoms. t is an integer of 0-2.

In the above formula (Z-3), R ^a7 and R ^a8 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon having 6 to 12 carbon atoms. group, or an -OSO ₂ -R ^R or _-SO 2 -R ^S, or two or more are combined with each other configured ring of these groups. R ^R and R ^S are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or unsubstituted carbon. It is an aromatic hydrocarbon group of formula 6-12. k6 and k7 are each independently an integer of 0 to 5. R ^{a7, R} a8, ^R when ^R and ^{R S} is plural respective plurality of ^{R a7,} R a8, ^{R R} and ^{R S} may be the same as or different from each other.

Examples of the alkyl group represented by R ^{a1 to} R ^a3 , R ^a4 , R ^a5 , R ^a7 and R ^a8 include linear alkyl groups such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group;
Examples thereof include branched alkyl groups such as i-propyl group, i-butyl group, sec-butyl group and t-butyl group.

Examples of the aromatic hydrocarbon group represented by R ^{a1 to} R ^a3 , R ^a4 and R ^a5 include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group;
Examples include aralkyl groups such as benzyl group and phenethyl group.

Examples of the aromatic hydrocarbon group represented by R ^a4 and R ^a5 include a phenyl group, a tolyl group, and a benzyl group.

Examples of the divalent organic group represented by R ^a6 include a group obtained by removing one hydrogen atom from the monovalent organic group represented by R ^{4 in} the above formula (a-3).

  Examples of the substituent for substituting the hydrogen atom of the alkyl group and aromatic hydrocarbon group 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, acyloxy group and the like. Among these, a halogen atom is preferable and a fluorine atom is more preferable.

R ^{a1 to} R ^a3 , R ^a4 , R ^a5 , R ^a7 and R ^a8 include an unsubstituted alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, —OSO ₂ —R ″ and —SO ₂ —R ″ is preferable, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferable, and a fluorinated alkyl group is further preferable. R ″ is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

  As k1, k2, and k3 in Formula (Z-1), integers of 0 to 2 are preferable, 0 and 1 are more preferable, and 0 is more preferable. As k4 in Formula (Z-2), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 1 is more preferable. k5 is preferably an integer of 0 to 2, more preferably 0 and 1, and still more preferably 0. As r, 2 and 3 are preferable, and 2 is more preferable. As t, 0 and 1 are preferable, and 0 is more preferable. As k6 and k7 in Formula (Z-3), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is more preferable.

Among these, cation (Z-1) and cation (Z-2) are preferable as Z ⁺ , and triphenylsulfonium cation and 4-butoxynaphthalen-1-yltetrahydrothiophenium cation are more preferable.

  [B1a] Examples of the acid generator include compounds represented by the following formulas (4-1-1) to (4-1-15) (hereinafter referred to as “compounds (4-1-1) to (4-1-1)”. 15) ")) and the like. [B1b] Examples of the acid generator include compounds represented by the following formulas (4-2-1) to (4-2-3) (hereinafter referred to as “compounds (4-2-1) to (4-2-2)”. 3) ")) and the like. [B1c] Examples of the acid generator include compounds represented by the following formula (4-3-1) and formula (4-3-2) (hereinafter referred to as “compound (4-3-1), (4-3)”. -2) "). [B1d] Examples of the acid generator include compounds represented by the following formula (4-4-1) and formula (4-4-2) (hereinafter referred to as “compound (4-4-1), (4-4)”. -2) ").

The above formulas (4-1-1) to (4-1-15), (4-2-1) to (4-2-3), (4-3-1), (4-3-2), In (4-4-1) and (4-4-2), Z ⁺ is a monovalent onium cation.

  [B1] As the acid generator, [B1a] acid generator is preferable, and the compounds (4-1-1), (4-1-2), (4-1-11) and (4-1-12) are preferred. Is more preferable.

  [B1] As the acid generator, onium salt compounds are preferable, sulfonium salts and tetrahydrothiophenium salts are more preferable, and triphenylsulfonium salts and 4-butoxynaphthalen-1-yltetrahydrothiophenium salts are more preferable.

  [B] The acid generator is also preferably a polymer in which the structure of an acid generator such as a polymer having a structural unit represented by the following formula (4-1 ′) is incorporated as a part of the polymer. .

In the above formula (4-1 ′), R ^p7 represents a hydrogen atom or a methyl group. L ⁴ is a single bond or —COO— or a divalent carbonyloxy hydrocarbon group. R ^p8 is a fluorinated alkanediyl group having 1 to 10 carbon atoms. Z ⁺ is synonymous with the above formula (4).

As R ^p7 , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable, from the viewpoint of copolymerization of the monomer that gives the structural unit represented by the above formula (4-1 ′).

L ⁴ is preferably a divalent carbonyloxy hydrocarbon group, more preferably a carbonyloxyalkanediyl group or a carbonylalkanediylarenediyl group.

R ^p8 is preferably a fluorinated alkanediyl group having 1 to 4 carbon atoms, more preferably a perfluoroalkanediyl group having 1 to 4 carbon atoms, and still more preferably a hexafluoropropanediyl group.

  [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 component. 1 part by mass is more preferable, 4 parts by mass is further preferable, and 7 parts by mass is particularly preferable. As an upper limit of the said content, 50 mass parts is preferable, 40 mass parts is more preferable, 30 mass parts is further more preferable, 25 mass parts is especially preferable. [B] By setting the content of the acid generator and the above range, the radiation-sensitive resin composition has improved sensitivity and developability, and as a result, LWR performance and the like can be further improved. [B] The acid generator can contain 1 type (s) or 2 or more types.

<[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 the alcohol solvent include aliphatic monoalcohol solvents having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcohol solvent having 3 to 18 carbon atoms such as cyclohexanol;
A C2-C18 polyhydric alcohol solvent such as 1,2-propylene glycol;
Examples thereof include C3-C19 polyhydric alcohol partial ether solvents such as propylene glycol monomethyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and 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 ester solvents include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvents such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate;
Polycarboxylic acid diester solvents such as diethyl oxalate;
Examples thereof include carbonate solvents such as dimethyl carbonate and diethyl carbonate.

Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents having 5 to 12 carbon atoms such as n-pentane and n-hexane;
Examples thereof include aromatic hydrocarbon solvents having 6 to 16 carbon atoms such as toluene and xylene.

  Among these, ester solvents and ketone solvents are preferable, polyhydric alcohol partial ether carboxylate solvents and cyclic ketone solvents are more preferable, and propylene glycol monomethyl ether acetate and cyclohexanone are more preferable. The radiation-sensitive resin composition may contain one or more [C] solvents.

<[D] Acid diffusion controller>
The said radiation sensitive resin composition may contain a [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. Further, the storage stability of the radiation sensitive resin composition is improved, and the resolution as a resist is further improved. Furthermore, a change in the line width 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 (B) (hereinafter also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (I)”). "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. It is done.

In the above formula (B), R ²⁰ , R ²¹ and R ²² are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, aryl group or aralkyl group. .

  Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; aromatic amines such as aniline. It is done.

  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; 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; pyrazine and pyrazole.

  As the nitrogen-containing organic compound, a compound having an acid dissociable group can also be used. 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 (5-1), an iodonium salt compound represented by the following formula (5-2), and the like.

In the above formulas (5-1) and (5-2), R ^{23 to} R ²⁷ are each independently 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 ^β —COO ⁻ , R ^β —SO ₃ ^— or the following formula (5-3). However, R ( ^beta) is an alkyl group, an aryl group, or an aralkyl group.

In the above formula (5-3), R ²⁸ 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 1 carbon atom. -12 linear or branched alkoxy groups. u is an integer of 0-2. When u is 2, two R ²⁸ may be the same or different.

  Examples of the photodegradable base include compounds represented by the following formulas.

  Of these, the photodegradable base is preferably a sulfonium salt, more preferably a triarylsulfonium salt, and even more preferably triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate.

  When the radiation sensitive resin composition contains a [D] acid diffusion controller as the [D] acid diffusion controller, the lower limit of the content of the [C] acid diffusion controller is 100 masses of the [A] polymer. 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>
[E] The polymer is a polymer having a larger mass content of fluorine atoms than the [A] polymer. When the radiation-sensitive resin composition contains the [E] polymer, when the resist film is formed, the distribution is near the resist film surface due to the oil-repellent characteristics of the fluoropolymer in the film. There is a tendency to be unevenly distributed, and it is possible to prevent the acid generator, the acid diffusion controller, and the like from being eluted into the immersion medium during 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 a [E] polymer, the resist film suitable for an immersion exposure method can be formed.

[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. 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), and 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 (6a). [E] A polymer can adjust a fluorine atom content rate by having a structural unit (Ea).

In said formula (6a), ^RD is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, —CO—O—, —SO ₂ —O—NH—, —CO—NH— or —O—CO—NH—. R ^E is a monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms or a monovalent fluorinated aliphatic alicyclic hydrocarbon group having 4 to 20 carbon atoms.

The monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by R ^E, such as 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.

The monovalent fluorine-cycloaliphatic hydrocarbon radical having 4 to 20 carbon atoms represented by R ^E, for example mono-fluoro cyclopentyl group, difluorocyclopentyl groups, perfluorocyclopentyl group, monofluoromethyl cyclohexyl group, difluorocyclopentyl groups, 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 linear partially fluorinated alkyl (meth) acrylates such as 2,2,2-trifluoroethyl (meth) acrylate;
Branched partially fluorinated alkyl (meth) acrylates such as 1,1,1,3,3,3-hexafluoro i-propyl (meth) acrylate;
Linear perfluoroalkyl (meth) acrylates such as perfluoroethyl (meth) acrylate;
(Meth) acrylic acid ester having a fluorinated chain hydrocarbon group such as branched perfluoroalkyl (meth) acrylic acid ester such as perfluoro i-propyl (meth) acrylic acid ester,
(Meth) acrylic having a monocyclic fluorinated alicyclic saturated hydrocarbon group such as perfluorocyclohexylmethyl (meth) acrylic acid ester, monofluorocyclopentyl (meth) acrylic acid ester, perfluorocyclopentyl (meth) acrylic acid ester Acid esters;
(Meth) acrylic acid ester having a fluorinated alicyclic hydrocarbon group such as (meth) acrylic acid ester having a polycyclic fluorinated alicyclic saturated hydrocarbon group such as fluoronorbornyl (meth) acrylic acid ester Etc. Among these, (meth) acrylic acid ester having a fluorinated chain hydrocarbon group is preferable, linear partially fluorinated alkyl (meth) acrylic acid ester is more preferable, and 2,2,2-trifluoroethyl (meta Acrylic acid esters are more preferred.

  [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, 95 mol% is preferable, 75 mol% is more preferable, and 40 mol% is further more preferable. By setting such a content ratio, a higher dynamic contact angle on the resist film surface can be expressed at the time of immersion exposure.

[Structural unit (Eb)]
The structural unit (Eb) is a structural unit represented by the following formula (6b). Since the [E] polymer has a 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 said formula (6b), R ^<F> is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ²⁹ is a (s + 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 at the R ³⁰ side of R ²⁹ Also includes a structure in which —CO—NH— is bonded. R ′ is a hydrogen atom or a monovalent organic group. R ³⁰ 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. X ² is a divalent chain fluorinated hydrocarbon group having 1 to 20 carbon atoms. A ¹ is an oxygen atom, —NR ″ —, —CO—O— *, or —SO ₂ —O— *. R ″ is a hydrogen atom or a monovalent organic group. * ^Indicates a binding site that binds to ^{R 31.} R ³¹ is a hydrogen atom or a monovalent organic group. s is an integer of 1 to 3. However, when s is 2 or 3, the plurality of R ³⁰ , X ² , A ¹ and R ³¹ may be the same or different.

When R ³¹ 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 ³¹ include an acid dissociable group, an alkali dissociable group, or 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 (6b-1) to (6b-3).

In the above formulas (6b-1) to (6b-3), R ^{29 ′} is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. R ^F , X ² , R ³¹ and s are as defined in the above formula (6b). When s is 2 or 3, the plurality of X ² and R ³¹ may be the same or different.

  [E] When a polymer has a structural unit (6b), as a minimum of the content rate of a structural unit (6b), 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 setting it as such a content rate, 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, 80 mol% is more preferable, and 75 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.

<Other optional components>
The radiation-sensitive resin composition may contain other optional components in addition to the above [A] to [E]. Examples of the other optional components include uneven distribution accelerators, surfactants, alicyclic skeleton-containing compounds, and sensitizers. Each of these other optional components may be used alone or in combination of two or more.

[Uneven distribution promoter]
The uneven distribution accelerator has an effect of segregating the [E] polymer on the resist film surface more efficiently when the radiation-sensitive resin composition contains the [E] polymer. By including this uneven distribution accelerator in 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 resist film to the immersion liquid without impairing the resolution, LWR performance, etc., and to perform immersion exposure at a higher speed by high-speed scanning. As a result, it is possible to improve the hydrophobicity of the resist film surface, which suppresses immersion-derived defects such as watermark defects. Examples of such an uneven distribution promoter include low molecular compounds having a relative dielectric constant of 30 or more and 200 or less and a boiling point at 1 atm of 100 ° C. or more. 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.

  When the radiation-sensitive resin composition contains an uneven distribution accelerator, the lower limit of the content of the uneven distribution accelerator is 10 mass with respect to 100 parts by mass of the total amount of the polymer in the radiation-sensitive resin composition. Part is preferable, 15 parts by mass is more preferable, 20 parts by mass is further preferable, and 25 parts by mass is particularly 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.

[Surfactant]
Surfactants have the effect of improving coatability, striation, developability, and the like. 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; commercially available products 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. 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, and the like.

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. As an upper limit of content of an alicyclic frame | skeleton containing compound in the said radiation sensitive resin composition, 5 mass parts is preferable with respect to 100 mass parts of [A] polymers.

[Sensitizer]
A sensitizer exhibits the effect | action which increases the production amount of the acid from [B] acid generator etc., and there exists an effect which improves the "apparent sensitivity" of the said radiation sensitive resin composition.

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

<Method for preparing radiation-sensitive resin composition>
The radiation sensitive resin composition is prepared by mixing, for example, [A] polymer, [B] acid generator, [C] solvent, and [D] acid diffusion control agent contained as necessary at a predetermined ratio. Preferably, the obtained mixture can be prepared by, for example, filtering through a filter having a pore diameter 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>
In the resist pattern forming method, a step of applying the radiation-sensitive resin composition to one surface of a substrate (hereinafter also referred to as “coating step”) and a resist film obtained by the coating step are exposed. And a step of developing the exposed resist film (hereinafter also referred to as “developing step”).

  According to the resist pattern forming method, since the radiation-sensitive resin composition is used, the LWR is small, the resolution is high, and the cross-sectional shape is rectangular while exhibiting excellent depth of focus and film shrinkage suppression. A resist pattern having excellent properties can be formed. Hereinafter, each step will be described.

[Coating process]
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, and roll coating. After coating, 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. As a minimum of the above-mentioned time, 600 seconds are preferred and 300 seconds are more preferred. 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.

  When immersion exposure is performed and the radiation-sensitive resin composition does not contain a water-repellent polymer additive, the direct immersion of the immersion liquid and the resist film is performed on the formed resist film. In order to avoid contact, an immersion protective film that is 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). As the exposure light, electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays and γ rays; charged particle beams such as electron beams and α rays, depending on the line width of the target pattern. Etc. 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. Further preferred.

  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 (PEB) is performed, and in the exposed portion of the resist film, the acid dissociable group of the [A] polymer or the like by the acid generated from the [B] acid generator or the like by the exposure It is preferable to promote dissociation. 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.

  According to the resist pattern forming method, since the radiation sensitive resin composition described above is used, shrinkage of the resist film during PEB can be suppressed.

[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 water or a rinse solution such as alcohol and then dry. The development method in the development step may be alkali development or organic solvent development. In the case of organic solvent development, since the exposed portion forms a resist pattern, the radiation-sensitive resin composition has a great advantage due to its excellent film shrinkage suppression.

  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, the 1 type (s) or 2 or more types of the solvent enumerated as the [E] 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, for example, a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (dip method), a method in which the developer is raised on the surface of the substrate by surface tension and is left stationary for a certain time (paddle method) ), A method of spraying the developer on the substrate surface (spray method), a method of continuously applying the developer while scanning the developer coating nozzle on the substrate rotating at a constant speed (dynamic dispensing method) Etc.

<Polymer>
The polymer is a polymer having a structural unit containing the group (I). Since the polymer has the above-mentioned properties, it can be suitably used as a polymer component of the radiation-sensitive resin composition, and the radiation-sensitive resin composition containing the polymer has LWR performance, resolution, Excellent cross-sectional rectangularity, depth of focus, and film shrinkage suppression.

<Compound>
The compound is a compound represented by the above formula (i). 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.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Using Tosoh 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 a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.), deuterated chloroform was used as a measurement solvent, and analysis for determining the content ratio (mol%) of each structural unit in each polymer was performed.

<Synthesis of compounds>
[Example 1] (Synthesis of Compound (M-1))
In a 300 mL round bottom flask (m-1) 13.8 g (78.5 mmol), diacetyl 13.5 g (157 mmol), trimethyl orthoformate 25.0 g (236 mmol), methanol 100 mL, p-toluenesulfonic acid monohydrate 1.49 g (7.85 mmol) was added, and the mixture was heated and stirred at 70 ° C. for 6 hours. After cooling to room temperature, excess diacetyl and trimethyl orthoformate were distilled off under reduced pressure. Ethyl acetate was added, and the mixture was washed 3 times with a saturated aqueous sodium hydrogen carbonate solution. After washing once with water, it was dried over anhydrous sodium sulfate. After the solvent was distilled off, the residue was purified by column chromatography to obtain 10.2 g (yield 45%) of (M-1).

[Examples 2 to 12] (Synthesis of compounds (M-2) to (M-12))
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-12).

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

[[A] Synthesis of polymer]
[Example 13] (Synthesis of polymer (A-1))
Compound (M-1) 4.79 g (20 mol%), compound (M′-10) 5.51 g (30 mol%) and compound (M′-1) 9.70 g (50 mol%) were converted to 2-butanone. It melt | dissolved in 40g and added AIBN 0.72g (5 mol% with respect to all the monomers) as a radical polymerization 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 reaction solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization reaction liquid was put into 400 g of methanol, 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 synthesize a white powdered polymer (A-1) (16.8 g, yield 84). %). 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′-10) and (M′-1) was 19.9 mol%, 30.2 mol%, respectively. And 49.9 mol%.

[Examples 14 to 33 and 35 to 41 and Synthesis Examples 1 to 11] (Polymers (A-2) to (A-21) and (A-23) to (A-29) and (CA-1)) (Synthesis of (CA-11))
Polymers (A-2) to (A-21) and (A-23) to (A-23) are obtained by performing the same operations as in Example 13 using the monomers shown in Tables 1 to 3 and the amounts used. (A-29) and (CA-1) to (CA-11) were synthesized.

[Example 34] (Synthesis of polymer (A-22))
47.0 g (60 mol%) of compound (M′-3), 53.0 g (40 mol%) of compound (M-1), 3.97 g of AIBN as a radical polymerization initiator (5 mol based on all monomers) %) And 1,14 g of t-dodecyl mercaptan were dissolved in 100 g of propylene glycol monomethyl ether, and then polymerized for 16 hours while maintaining the reaction temperature at 70 ° C. in a nitrogen atmosphere. After completion of the polymerization reaction, the polymerization reaction solution was dropped into 1,000 g of n-hexane to solidify and purify the polymer. Next, 150 g of propylene glycol monomethyl ether was added to the obtained polymer again, and then 150 g of methanol, 34 g of triethylamine and 6 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the resulting polymer was dissolved in 150 g of acetone, then dropped into 2,000 g of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. It was dried for a while to obtain a white powdery polymer (A-22) (66.2 g, yield 75%). Mw of the polymer (A-22) was 7400, and Mw / Mn was 1.89. As a result of ¹³ C-NMR analysis, the content of each structural unit derived from p-hydroxystyrene and (M-1) was 60.1 mol% and 39.9 mol%, respectively.

[[E] Synthesis of polymer]
[Synthesis Example 12] (Synthesis of Polymer (E-1))
79.9 g (70 mol%) of the compound (M′-12) and 20.91 g (30 mol%) of the compound (M′-17) were dissolved in 100 g of 2-butanone to give dimethyl 2 as a radical polymerization initiator. , 2′-Azobisisobutyrate 4.77 g was dissolved to prepare a monomer solution. 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 reaction solution was cooled with water and cooled to 30 ° C. or lower. After transferring the polymerization reaction liquid to a 2 L separatory funnel, the polymerization reaction liquid 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) (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′-12) and (M′-17) was 71.1 mol% and 28.9 mol%, respectively.

<Preparation of radiation-sensitive resin composition>
The [B] acid generator, [C] solvent, [D] acid diffusion controller and [F] uneven distribution accelerator used for the preparation of the radiation sensitive resin composition are 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-dii -Propylaniline D-5: Tris [2- (2-methoxymethoxy) ethyl] amine

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

[Preparation of radiation-sensitive resin composition for ArF exposure]
[Example 42]
[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, (E-1) 3 parts by weight as a polymer, and [F] The radiation sensitive resin composition (J-1) was prepared by mixing 30 parts by mass of (F-1) as an uneven distribution accelerator and filtering the obtained mixture through a membrane filter having a pore size of 0.2 μm. did.

[Examples 43 to 73 and Comparative Examples 1 to 11]
Except having used each component of the kind and content shown in following Table 4 and Table 5, it operated similarly to Example 42, and the radiation sensitive resin compositions (J-2)-(J-32) and ( CJ-1) to (CJ-11) were prepared.

<Formation of resist pattern (1)> (Line and space pattern, organic solvent development)
[Examples 74 to 105 and Comparative Examples 13 to 24]
After applying a composition for forming a lower antireflection film (“ARC66” from Nissan Chemical Industries, Ltd.) using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron) on the surface of a 12-inch silicon wafer, By heating at 205 ° C. for 60 seconds, a lower antireflection film having an average thickness of 105 nm was formed. On the lower antireflection film, the prepared radiation sensitive resin composition 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 subjected to an optical condition of NA = 1.3 and dipole (Sigma 0.977 / 0.782) using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON). , Exposed through a 40 nm line and space (1L1S) mask pattern. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, the organic solvent was developed using n-butyl acetate and dried to form a negative resist pattern. When this resist pattern is formed, the line width formed through a one-to-one line and space mask having a target dimension of 40 nm is defined as an optimum exposure amount. did.

<Evaluation>
By measuring according to the following method about the formed resist pattern, each radiation sensitive resin composition was evaluated about the following item. A scanning electron microscope (Hitachi High-Technologies “CG-4100”) was used for measuring the resist pattern. The evaluation results are shown in Table 6 below.

[LWR performance]
The resist pattern was observed from above the pattern using the scanning electron microscope. A total of 50 line widths were measured at arbitrary points, a 3 sigma value was determined from the distribution of the measured values, and this value was defined as LWR performance (nm). The LWR performance indicates that the smaller the value, the better. The LWR performance can be evaluated as “good” when it is 4.00 nm or less and “bad” when it exceeds 4.00 nm.

[Resolution]
When exposure is performed through a mask pattern having a one-to-one line-and-space with a target dimension of 40 nm at an exposure amount equal to or less than the optimum exposure amount, a resolution ( nm). The resolution can be evaluated as “good” when it is 35 nm or less, and “bad” when it exceeds 35 nm.

[Rectangularity of the cross-sectional shape]
Observe the cross-sectional shape of the resist pattern resolved at the optimum exposure amount, measure the line width Lb at the middle of the resist pattern and the line width La at the top of the film, and calculate La / Lb. It was used as an index of the rectangularity of the cross-sectional shape. The rectangularity of the cross-sectional shape is “good” when 0.90 ≦ La / Lb ≦ 1.10 and “bad” when La / Lb <0.90 or 1.10 <La / Lb. Can be evaluated.

[Depth of focus]
In the resist pattern resolved at the above optimum exposure amount, the dimension when the focus is changed in the depth direction is observed, and the depth direction in which the pattern dimension falls within 90% to 110% of the standard without any bridge or residue. Was measured, and the measurement result was defined as the depth of focus (nm). The depth of focus indicates that the larger the value, the better. The depth of focus can be evaluated as “good” when the depth is 40 nm or more, and “bad” when the depth of focus is less than 40 nm.

[Membrane shrinkage suppression]
A resist film having an average thickness of 90 nm was formed by the method described in “Formation of resist pattern (1)”. Next, the resist film was exposed at 70 mJ using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON), and then the film thickness was measured to obtain the film thickness A. Subsequently, after performing PEB for 60 seconds at 90 degreeC, the film thickness measurement was implemented again and the film thickness B was calculated | required. 100 × (A−B) / A (%) was calculated from the values of the film thickness A and the film thickness B, and the value of the film shrinkage rate by this PEB was used as an index of the film shrinkage inhibition property. It shows that a film shrinkage | contraction suppression property is so good that a value is small. The film shrinkage inhibiting property can be evaluated as “good” when it is 20% or less, and “bad” when it exceeds 20%.

<Formation of resist pattern (2)> (Hole pattern, organic solvent development)
[Examples 106 to 137 and Comparative Examples 25 to 36]
After applying a composition for forming a lower antireflection film (“ARC66” from Nissan Chemical Industries, Ltd.) using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron) on the surface of a 12-inch silicon wafer, By heating at 205 ° C. for 60 seconds, a lower antireflection film having an average thickness of 105 nm was formed. On the lower antireflection film, the prepared radiation sensitive resin composition 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 subjected to an optical condition of NA = 1.3 and cross pole (Sigma 0.977 / 0.782) using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON). Then, exposure was performed through a mask for pattern formation of 45 nm holes / 90 nm pitch. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, the organic solvent was developed using n-butyl acetate and dried to form a negative resist pattern. When this resist pattern was formed, the exposure amount with which the target dimension was formed in a 45 nm hole was determined as the optimum exposure amount.

<Evaluation>
By measuring according to the following method about the formed resist pattern (hole pattern), each radiation sensitive resin composition was evaluated about the following item. A scanning electron microscope (Hitachi High-Technologies “CG-4100”) was used for measuring the resist pattern. The evaluation results are shown in Table 7 below.

[MEEF performance]
Using the 46 nm, 45.5 nm, 44.5 nm, and 44 nm hole pattern forming masks at the above optimum exposure doses, the hole size when a 90 nm pitch hole pattern was formed was measured. The slope of the straight line when the hole pattern formation mask size (nm) was plotted on the horizontal axis and the hole pattern size (nm) formed on the resist film after exposure was plotted on the vertical axis was determined as MEEF performance. The MEEF performance can be evaluated as “good” when 4.0 or less and “bad” when 4.0 or more.

[CDU performance]
A total of 1,800 dimensions of 45 nm hole patterns formed at the above optimum exposure dose were measured at arbitrary points to determine the hole diameter variation (3σ), which was taken as CDU performance (nm). It can be evaluated that the CDU performance is better as the value of 3σ is smaller. The CDU performance can be evaluated as “good” when it is 5.5 nm or less, and “bad” when it exceeds 5.5 nm.

[Resolution]
When exposure is performed through a mask pattern having a target dimension of 45 nm holes and 90 nm pitch at an exposure amount equal to or greater than the optimum exposure amount, the minimum dimension of the hole pattern obtained with an increase in exposure amount is defined as resolution (nm). . The resolution can be evaluated as “good” when it is 35 nm or less, and “bad” when it exceeds 35 nm.

  As is clear from the results in Table 6, the radiation-sensitive resin compositions of the examples had LWR performance in line and space pattern formation, resolution, rectangularity of the cross-sectional shape, depth of focus and PEB shrinkage in the case of ArF exposure. As shown in Table 7, it is excellent in suppression, and is excellent in MEEF performance, CDU performance and resolution in hole pattern formation.

[Preparation of radiation-sensitive resin composition for electron beam exposure]
[Example 138]
[A] 100 parts by mass of (A-1) as a polymer, [B] 20 parts by mass of (B-1) as an acid generator, [C] 4,280 parts by mass of (C-1) as a solvent, and (C-2) 1,830 parts by mass and [D] 3.6 parts by mass of (D-1) acid diffusion controller are mixed, and the resulting mixture is filtered through a membrane filter having a pore size of 0.2 μm. Thus, a radiation sensitive resin composition (J-33) was prepared.

[Examples 139 to 141 and Comparative Example 37]
Except having used each component of the kind and content shown in the following Table 8, it operated similarly to Example 138 and the radiation sensitive resin compositions (J-34)-(J-36) and (CJ-13) ) Was prepared.

<Formation of resist pattern (3)> (Organic solvent development)
[Examples 142 to 145 and Comparative Example 38]
Using the spin coater (“CLEAN TRACK ACT8” manufactured by Tokyo Electron Ltd.) on the surface of an 8-inch silicon wafer, the prepared radiation sensitive resin composition was applied, 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 50 nm. Next, the resist film was irradiated with an electron beam by using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 120 ° C. for 60 seconds. Thereafter, development was performed using n-butyl acetate, followed by drying to form a negative resist pattern.

<Evaluation>
About the formed resist pattern, it carried out similarly to said "resist pattern formation (1)", and evaluated LWR performance, resolution, rectangularity of a cross-sectional shape, and depth of focus. In the case of electron beam exposure, the LWR performance can be evaluated as “good” when it is 5.00 nm or less, and “bad” when it exceeds 5.00. The evaluation results are shown in Table 9 below.

  As is clear from the results in Table 9, the radiation-sensitive resin compositions of the examples are excellent in LWR performance, resolution, cross-sectional rectangularity and depth of focus in the case of electron beam exposure. It is estimated that the radiation sensitive resin composition of an Example is excellent also in film | membrane shrinkage | contraction suppression property like the case of the above-mentioned ArF exposure. In general, electron beam exposure is known to show the same tendency as in EUV exposure. Therefore, according to the radiation-sensitive resin compositions of the examples, in the case of EUV exposure. Is presumed to be excellent in LWR performance and the like.

  According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern that exhibits excellent depth of focus and film shrinkage suppression, low LWR, high resolution, and excellent cross-sectional rectangularity. Can be formed. 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 (9)

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

(In formula (1), R ¹ , R ² and R ³ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a hydrogen 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, and two or more of R ^{1 to} R ⁵ and L are mutually bonded. And a ring structure having 3 to 20 ring members together with an atomic chain to which these are bonded, * represents a bonding site with a portion other than the group represented by the formula (1) in the first structural unit. Show.) The radiation sensitive resin according to claim 1, wherein R ⁴ and R ⁵ in the formula (1) are organic groups, and the organic group is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 16 carbon atoms. Composition. The radiation-sensitive composition according to claim 1 or 2, wherein the organic group of R ¹ , R ² and R ³ in the formula (1) is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 16 carbon atoms. Resin composition. The radiation sensitive resin composition according to claim 3, wherein the substituted or unsubstituted monovalent hydrocarbon group having 1 to 16 carbon atoms of R ¹ and R ² is represented by the following formula (2).

(In Formula (a), R ⁶ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 15 carbon atoms. ** is adjacent to the carbon atom to which R ⁴ in Formula (1) is bonded. And a site bonded to the oxygen atom adjacent to the carbon atom to which R ⁵ is bonded or R ⁵ is bonded.) The radiation-sensitive resin composition according to claim 1 or claim 2 represents a ring structure of L and R ³ and configured ring members 5 to 20 in conjunction with the keyed atom chain to which they are bound to each other in the above equation (1) object. The radiation sensitive resin composition according to any one of claims 1 to 5, wherein the first structural unit is represented by the following formula (A).

(In Formula (A), Z is a group represented by Formula (1) above. Y is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ⁷ and R ⁸ are Each independently represents a hydrogen atom or a methyl group, and R ⁹ is a hydrogen atom, a fluorine atom or a monovalent organic group having 1 to 20 carbon atoms.) A step of applying the radiation-sensitive resin composition according to any one of claims 1 to 6 to one surface of the substrate;
Exposing the resist film obtained by the coating step;
And a step of developing the exposed resist film. The polymer which has a structural unit containing group represented by following formula (1).

(In formula (1), R ¹ , R ² and R ³ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a hydrogen 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, and two or more of R ^{1 to} R ⁵ and L are mutually bonded. Together with the atomic chain to which these are bonded, a ring structure having 3 to 20 ring members may be represented, and * represents a bonding site with a portion other than the group represented by the formula (1) in the structural unit. ) A compound represented by the following formula (i).

(In formula (i), R ¹ , R ² and R ³ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a hydrogen 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, and two or more of R ^{1 to} R ⁵ and L are mutually bonded. And a ring structure having 3 to 20 ring members together with an atomic chain to which these are bonded, R ¹⁰ is a monovalent group containing a polymerizable carbon-carbon double bond.)