JP6028732B2 - Photoresist composition - Google Patents

Description

  The present invention relates to a photoresist composition.

  In the field of microfabrication for manufacturing integrated circuit elements, etc., irradiation (exposure) of short wavelength radiation represented by KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), etc. is performed in order to obtain a higher degree of integration. The lithography technology used is being developed. Resist materials suitable for these exposure light sources are required to have high sensitivity, high resolution, etc., and usually contain chemical components containing an acid-dissociable group and an acid generator that generates acid upon irradiation with radiation. An amplification type photoresist composition is used (see Patent Document 1).

  On the other hand, in recent years when further miniaturization of devices is progressing, techniques using X-rays, electron beams (EB), extreme ultraviolet rays (EUV), etc., which are shorter wavelengths than excimer lasers are also being studied. . However, when a finer resist pattern is formed using a conventional photoresist composition, it is appropriate that the acid diffusion distance in the resist film (hereinafter also referred to as “diffusion length”) is appropriately short. However, due to the inappropriate diffusion length, MEEF (Mask Error Enhancement Factor), Depth Of Focus, Line Width Roughness (LWR), which are indicators of mask error tolerance, are used. The present situation is that the lithography characteristics such as the above cannot be sufficiently satisfied.

  In view of such circumstances, photoresist compositions for forming finer resist patterns are desired not only to improve basic characteristics such as sensitivity and resolution, but also to improve MEEF, DOF, and LWR. Yes.

JP 59-45439 A

  The present invention has been made based on the above circumstances, and its purpose is to provide a photoresist composition that sufficiently satisfies not only basic characteristics such as sensitivity but also MEEF performance, DOF, and LWR. is there.

The invention made to solve the above problems is
[A] a polymer having an acid generating group (hereinafter also referred to as “[A] polymer”), and [B] at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, a sultone structure, and an alicyclic structure A photoresist composition containing an acid generator having a seed structure (hereinafter also referred to as “[B] acid generator”).

  In the photoresist composition, [A] the presence of an acid generating group in the polymer makes the distribution of the acid generated by exposure uniform, and the diffusion of acid from the exposed area to the unexposed area is moderate. Be controlled. [B] Since the acid generator has a bulky structure such as a lactone structure, a cyclic carbonate structure, a sultone structure, or an alicyclic structure, the photoresist composition can further reduce the acid diffusion length. Can do. As a result, in the photoresist composition, the acid diffusion is appropriately controlled, and the acid can uniformly and sufficiently act in the exposed portion. Therefore, not only basic characteristics such as sensitivity, but also MEEF performance, DOF and LWR is also fully satisfied.

[B] The acid generator preferably has at least one structure selected from the group consisting of a lactone structure and a sultone structure. Thus, when the [B] acid generator has a lactone structure and a sultone structure, the photoresist composition can appropriately shorten the acid diffusion length.
In addition, since the [B] acid generator is excellent in compatibility with the [A] polymer, it can function efficiently in the photoresist composition. As a result, the photoresist composition is excellent in MEEF performance, DOF and LWR.

（式（１）中、Ｒ^ｐ１は、水素原子、フッ素原子、トリフルオロメチル基又は炭素数１〜３のアルキル基である。Ｒ^ｐ２は、２価の有機基である。複数のＲｆは、それぞれ独立して、水素原子、フッ素原子又は炭素数１〜３のフッ素化アルキル基である。ｎは０〜６の整数である。Ｍ^＋は、オニウムカチオンである。
式（２）中、Ｒ^ｐ３は、水素原子、フッ素原子、トリフルオロメチル基又は炭素数１〜３のアルキル基である。Ｒ^ｐ４、Ｒ^ｐ５及びＲ^ｐ６は、それぞれ独立して、炭素数１〜１０の有機基である。ｍは、０〜３の整数である。ｍが２又は３の場合、複数のＲ^ｐ４は、それぞれ同一でも異なっていてもよい。Ａは、単結合、メチレン基、炭素数２〜１０のアルキレン基、炭素数２〜１０のアルキレンオキシ基、又は炭素数６〜１０のアリーレン基である。Ｘ⁻は、スルホネートアニオン、カルボキシレートアニオン又はアミドアニオンである。）[A] The polymer comprises at least one structural unit selected from the group consisting of the structural unit (I) represented by the following formula (1) and the structural unit (II) represented by the following formula (2): It is good to include.

(In formula (1), R ^p1 is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ^p2 is a divalent organic group. Each independently represents a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 3 carbon atoms, n is an integer of 0 to 6. M ⁺ is an onium cation.
In Formula (2), R ^p3 is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ^p4 , R ^p5 and R ^p6 are each independently an organic group having 1 to 10 carbon atoms. m is an integer of 0-3. When m is 2 or 3, the plurality of R ^p4 may be the same or different from each other. A is a single bond, a methylene group, an alkylene group having 2 to 10 carbon atoms, an alkyleneoxy group having 2 to 10 carbon atoms, or an arylene group having 6 to 10 carbon atoms. X ⁻ is a sulfonate anion, a carboxylate anion or an amide anion. )

  [A] Since the polymer itself has an ionic acid generating group having the above specific structure, the photoresist composition allows the acid to be uniformly distributed in the polymer chain, and also from the exposed part. In addition to controlling the diffusion of acid to the exposed area, the hydrophilicity of the exposed area is increased. Thereby, in the exposed part, the reactivity to the developer is further improved, and thus the photoresist composition is excellent in MEEF performance, DOF and LWR.

（式（３）中、Ｒ^ｐ７〜Ｒ^ｐ９は、それぞれ独立して、炭素数１〜３０の炭化水素基である。但し、Ｒ^ｐ７及びＲ^ｐ８は、互いに結合して、それらが結合している硫黄原子と共に環状構造を形成していてもよい。上記炭化水素基が有する水素原子の一部又は全部は置換されていてもよい。）[A] The polymer may include the structural unit (I) represented by the above formula (1), and M ^{+ in the} above formula (1) may be represented by the following formula (3).

(In formula (3), R ^{p7 to} R ^p9 are each independently a hydrocarbon group having 1 to 30 carbon atoms, provided that R ^p7 and R ^p8 are bonded to each other, A cyclic structure may be formed together with the sulfur atom, and a part or all of the hydrogen atoms of the hydrocarbon group may be substituted.)

  When the ionic acid generating group of the structural unit (I) represented by the formula (1) has a cation represented by the formula (3), the photoresist composition has MEEF performance, DOF, and Excellent with LWR.

（式（４）中、Ｒ^ｐ１０〜Ｒ^ｐ１２は、それぞれ独立してヒドロキシ基、ハロゲン原子、アルキル基、シクロアルキル基、アルコキシ基、−Ｓ−Ｒ^ｘ基又は複数のヘテロ原子を有する基である。Ｒ^ｘは、アルキル基又はアリール基である。但し、上記アルキル基、シクロアルキル基、アルコキシ基及びアリール基が有する水素原子の一部又は全部は置換されていてもよい。ａは、１〜５の整数である。ｂ及びｃは、それぞれ独立して、０〜５の整数である。）[A] The polymer may include the structural unit (I) represented by the above formula (1), and M ^{+ in the} above formula (1) may be represented by the following formula (4).

(In formula (4), R ^{p10 to} R ^p12 are each independently a hydroxy group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an —S—R ^x group or a group having a plurality of heteroatoms. R ^x is an alkyl group or an aryl group, provided that a part or all of the hydrogen atoms of the alkyl group, cycloalkyl group, alkoxy group and aryl group may be substituted. (It is an integer of 5. b and c are each independently an integer of 0 to 5.)

  When the ionic acid generating group of the structural unit (I) represented by the formula (1) has a cation represented by the formula (4), the photoresist composition has MEEF performance, DOF, and Excellent with LWR.

Of the R ^{p10 to} R ^p12 , at least one is preferably a group represented by the following formula (4-1) or the following formula (4-2).
-OSO ₂ -R ^x ··· (4-1)
-SO ₂ -R ^x ··· (4-2)
(In formulas (4-1) and (4-2), R ^x has the same meaning as in formula (4) above.)

  The said photoresist composition is further excellent in MEEF performance, DOF, and LWR by containing the [A] polymer which has an onium cation containing the group of the said specific structure.

[A] The polymer may include the structural unit (II) represented by the above formula (2), and X ^{− in the} above formula (2) may be represented by the following formula (5).
R ^p13 —SO ₃ ^— (5)
(In formula (5), R ^p13 is a monovalent organic group having a fluorine atom.)

  When the ionic acid generating group of the structural unit (II) represented by the above formula (2) has an anion represented by the above formula (5), the photoresist composition has MEEF performance, DOF, and It is more excellent in LWR.

（式（６）中、Ｒ^１は、水素原子、フッ素原子、トリフルオロメチル基又は炭素数１〜３のアルキル基である。Ｒ^２〜Ｒ^４は、それぞれ独立して、炭素数１〜４のアルキル基又は炭素数４〜２０の脂環式基である。但し、Ｒ^３及びＲ^４は、互いに結合して、それらが結合している炭素原子と共に炭素数４〜２０の２価の脂環式基を形成してもよい。）[A] The polymer preferably further contains a structural unit (III) represented by the following formula (6).

(In the formula (6), ^{R 1} is ^.R 2 to R ⁴ a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms are each independently 1 to 4 carbon atoms Or an alicyclic group having 4 to 20 carbon atoms, provided that R ³ and R ⁴ are bonded to each other, and the divalent fatty acid having 4 to 20 carbon atoms together with the carbon atom to which they are bonded. A cyclic group may be formed.)

  The structural unit (III) represented by the above formula (6) has an acid dissociable group that is easily dissociated by the action of an acid. [A] In addition to the structural unit (I) or the structural unit (II) having an acid-generating group, the polymer further includes the structural unit (III) including such an acid-dissociable group. The acid generated from the acid generating group can efficiently dissociate the nearby acid dissociable group. Therefore, the said photoresist composition is excellent in a sensitivity, and can form a favorable fine pattern.

  [A] The polymer preferably further includes at least one structural unit (IV) selected from the group consisting of a structural unit having a lactone structure, a structural unit having a cyclic carbonate structure, and a structural unit having a sultone structure. .

  [A] The polymer further includes at least one structural unit (IV) selected from the group consisting of a structural unit having a lactone structure, a structural unit having a cyclic carbonate structure, and a structural unit having a sultone structure, The said photoresist composition is excellent in the adhesiveness to a board | substrate, and can form a favorable fine pattern.

The photoresist composition preferably further contains a [C] acid diffusion controller.
The photoresist composition further contains [C] an acid diffusion control agent, whereby the acid diffusion can be more appropriately controlled. As a result, the MEEF performance, DOF, and LWR are further improved.

  [C] The acid diffusion controller is preferably a photodegradable base. Since the photodegradable base has a property of decomposing upon exposure and losing acid diffusion control ability, the photoresist composition has a photodegradable base as a [C] acid diffusion control agent, so that in the unexposed portion. It is possible to control acid diffusion specifically. As a result, the photoresist composition is further excellent in MEEF performance, DOF and LWR.

  As described above, since the photoresist composition of the present invention contains a polymer having an acid-generating group and an acid generator having a lactone structure, a sultone structure, etc., it satisfies basic characteristics such as sensitivity and MEEF. Excellent performance, DOF and LWR. Therefore, a fine pattern can be formed with high accuracy by using the photoresist composition.

A plan view schematically showing the shape of a line and space pattern Sectional view schematically showing the shape of the line and space pattern

<Photoresist composition>
The photoresist composition contains a [A] polymer and a [B] acid generator. Furthermore, a [C] acid diffusion control agent is contained as a suitable component. In addition, as long as the effect of this invention is not impaired, you may contain another arbitrary component. Hereinafter, each component will be described in detail.

<[A] polymer>
[A] The polymer has an acid generating group. Here, the acid-generating group refers to a group that generates an acid by exposure in a pattern forming process. [A] Since the polymer itself has an acid generating group, the acid generated by exposure can be uniformly distributed in the polymer chain, and the diffusion of the acid from the exposed area to the unexposed area is controlled. . Accordingly, the photoresist composition is excellent in MEEF performance, DOF, and LWR because the acid can uniformly and sufficiently act in the exposed portion.

  [A] The polymer preferably includes the structural unit (I) represented by the above formula (1) or the structural unit (II) represented by the above formula (2) as the structural unit having an acid generating group. . Furthermore, it is preferable that the structural unit (III) and the structural unit (IV) are included, and other structural units other than the structural unit (I) to the structural unit (IV) may be included unless the effects of the present invention are impaired. Good. Hereinafter, each structural unit will be described in detail.

[Structural unit (I)]
The structural unit (I) is represented by the above formula (1).

In said formula (1), R ^<p1> is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or a C1-C3 alkyl group. R ^p2 is a divalent organic group. Several Rf is respectively independently a hydrogen atom, a fluorine atom, or a C1-C3 fluorinated alkyl group. n is an integer of 0-6. M ⁺ is an onium cation.

Examples of the alkyl group having 1 to 3 carbon atoms represented by R ^p1 include a methyl group, an ethyl group, and a propyl group. Of these, a methyl group is preferable. R ^p1 is preferably a hydrogen atom or a methyl group.

Examples of the divalent organic group represented by R ^p2 include a hydrocarbon group having 1 to 20 carbon atoms and a group represented by —R ^p21 —R ^p22 —. R ^p21 is a hydrocarbon group having 1 to 20 carbon atoms, and R ^p22 is —O—, —CO—, —COO—, —OCO—, —NH—, —NHCO—, —CONH—, or — NHCOO-.

Examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R ^p2 include:
Chain hydrocarbon groups such as methylene group, ethanediyl group, propanediyl group, butanediyl group, pentanediyl group, hexanediyl group, decandiyl group;
An alicyclic group obtained by removing two hydrogen atoms from an alicyclic structure such as cyclopentane, cyclohexane, dicyclopentane, tricyclodecane, tetracyclododecane, adamantane;
Examples thereof include aromatic hydrocarbon groups such as a phenylene group, a naphthylene group, and a biphenylene group.
However, some or all of the hydrogen atoms of these hydrocarbon groups may be substituted with fluorine atoms or the like.
Among these, a chain hydrocarbon group and an alicyclic group are preferable, and a chain hydrocarbon group is more preferable. Of these, a methylene group, an ethanediyl group, a propanediyl group, a butanediyl group, and a pentanediyl group are more preferable, and a methylene group and an ethanediyl group are particularly preferable.

Examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R ^p21 include the same groups as those exemplified as the hydrocarbon group having 1 to 20 carbon atoms represented by R ^p2 .

Examples of the group represented by —R ^p21 —R ^p22 — include —CH ₂ —O—, —CH ₂ —CO—, —CH ₂ —COO—, —CH ₂ —OCO—, and —CH ₂ —. _{NH -, - CH 2 -NHCO -} , - CH 2 -CONH -, - CH 2 -NHCOO -, - CH 2 -CH 2 -O -, - CH 2 -CH 2 -CO -, - CH 2 -CH 2 _{-COO -, - CH 2 -CH 2} -OCO -, - CH 2 -CH 2 -NH -, - CH 2 -CH 2 -NHCO -, - CH 2 -CH 2 -CONH -, - CH 2 -CH 2 _{-NHCOO -, - CH 2 -CH 2} -CH 2 -O -, - CH 2 -CH 2 -CH 2 -COO -, - CH 2 -CH 2 -CH 2 -OCO -, - CH 2 -CH 2 - _{CH 2 -NH -, - CH 2} -CH 2 -CH 2 -NHCO _{-, - CH 2 -CH 2 -CH} 2 -CONH -, - CH 2 -CH 2 -CH 2 -NHCOO -, - CH 2 -CH 2 -CHF-NHCOO -, - CH 2 -CH 2 -CH 2 - _{CH 2 -O -, - CH 2} -CH 2 -CH 2 -CH 2 -CO -, - CH 2 -CH 2 -CH 2 -CH 2 -COO -, - CH 2 -CH 2 -CH 2 -CH 2 _{-OCO -, - CH 2 -CH 2} -CH 2 -CH 2 -NH -, - CH 2 -CH 2 -CH 2 -CH 2 -NHCO -, - CH 2 -CH 2 -CH 2 -CH 2 -CONH _{-, - CH 2 -CH 2 -CH} 2 -CH 2 -NHCOO -, - CH 2 -CH 2 -CH 2 -CHF-NHCOO -, - CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CONH _-, - CH ₂ -CH ₂ -CH _{-CH 2 -CH 2 -NHCOO -, -} CH 2 -CH 2 -CH 2 -CH 2 -CHF-NHCOO- , and the like.

Of _{these, -CH 2 -NHCOO -, - CH} 2 -CH 2 -NHCOO- and _-CH 2 _-CH 2 _-CH 2 -NHCOO- _preferably, -CH ₂ -CH ₂ -NHCOO- is more preferable. Note that the ^-R p21 ^{-R p22} - group represented ^{by, R p21} are preferably bound to the ester group in the formula (1).

Examples of the fluorinated alkyl group having 1 to 3 carbon atoms represented by Rf include a monofluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 1-fluoroethyl group, a 1,2-difluoroethyl group, 1 1,2,2-tetrafluoroethyl group, and the like.
Rf is preferably a hydrogen atom or a fluorine atom, and more preferably a fluorine atom.

  As said n, 0-4 are preferable, 1-3 are more preferable, and 1 and 2 are further more preferable.

Examples of the onium cation represented by M ⁺ include a sulfonium cation and an iodonium cation. The onium cation is a group consisting of a sulfonium cation represented by the above formula (3) and an iodonium cation represented by the following formula (7). More preferred are at least one onium cation selected.

In said formula (3), R ^{<p7 >} -R ^< p9 ^> is respectively independently a C1-C30 hydrocarbon group. However, R ^p7 and R ^p8 may be bonded to each other to form a cyclic structure together with the sulfur atom to which they are bonded. Part or all of the hydrogen atoms of the hydrocarbon group may be substituted.

In the above formula ^(3), the hydrocarbon group having 1 to 30 carbon atoms represented by R p7 ^{to R p9,} for example,
Monovalent chain hydrocarbon groups such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group;
Monovalent alicyclic groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a dicyclopentyl group, a tricyclodecyl group, a tetracyclododecyl group, an adamantyl group;
A monovalent hydrocarbon group partially having the alicyclic structure;
Monovalent aromatic hydrocarbon groups such as phenyl group, naphthyl group, anthryl group, biphenyl group;
And monovalent hydrocarbon groups having an aromatic ring in part. Of these, monovalent aromatic hydrocarbon groups such as a phenyl group, a naphthyl group, an anthryl group, and a biphenyl group are preferable, and a phenyl group is more preferable.

Examples of the substituent that the hydrocarbon group may have include, for example, a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, a halogenated hydrocarbon group, an alkyl group, an alkoxyl group, an amino group, a thiol group, and an organic group. a sulfonyl group (RSO ₂ -) and the like. R is an alkyl group, a cycloalkyl group or an aryl group. Among these, a hydroxyl group, an alkyl group, an alkoxyl group, and a cyclohexylsulfonyl group are preferable, and a cyclohexylsulfonyl group is more preferable.

  Of the sulfonium cations represented by the above formula (3), the sulfonium cations represented by the above formula (4) are more preferable.

In formula (4), R ^{p10 to} R ^p12 each independently represent a hydroxy group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an —S—R ^x group or a group having a plurality of heteroatoms. R ^x is an alkyl group or an aryl group. However, one part or all part of the hydrogen atom which the said alkyl group, cycloalkyl group, alkoxy group, and aryl group have may be substituted. a is an integer of 1-5. b and c are each independently an integer of 0 to 5;

As said ^{Rp10- Rp12} , the group by which at least one is represented by the said Formula (4-1) and the said Formula (4-2) is preferable.

  Examples of the sulfonium cation represented by the above formula (3) include cations represented by the following formulas (i-1) to (i-23).

  Of these, the sulfonium cations represented by (i-1) and (i-23) are preferred.

In said formula (7), R ^<p14> is respectively independently a C1-C30 hydrocarbon group or a C4-C30 heterocyclic organic group. However, two R ^p14 may be bonded to each other to form a cyclic structure together with the iodine atom. Moreover, one part or all part of the hydrogen atom which the said hydrocarbon group and heterocyclic organic group have may be substituted.

In the above formula (7), the hydrocarbon group having 1 to 30 carbon atoms represented by R ^p14 is a hydrocarbon group having 1 to 30 carbon atoms represented by R ^{p7 to} R ^p9 in the above formula (3). And the same groups as those mentioned above.

Among these, R ^p14 is preferably a monovalent aromatic hydrocarbon group such as a phenyl group, a naphthyl group, an anthryl group, or a biphenyl group, and more preferably a phenyl group.

Examples of the substituent that the hydrocarbon group and the heterocyclic organic group may have are listed as the substituent that the hydrocarbon group represented by R ^{p7 to} R ^p9 in the above formula (3) may have. The same group as a group can be mentioned. Of these, a halogen atom, a nitro group, a halogenated hydrocarbon group, an alkyl group, and an alkoxyl group are preferable.

The monovalent onium cation represented by M ⁺ is preferably a sulfonium cation represented by the above formula (3), more preferably a sulfonium cation represented by the above formula (4), and among these, the above formula (i -1) and the sulfonium cation represented by (i-23) are more preferable.

In addition, the monovalent onium cation represented by M ⁺ in the above formula (1) is, for example, Advances in Polymer Science, Vol. 62, p. It can be produced according to the general method described in 1-48 (1984).

  Examples of the structural unit (I) represented by the above formula (1) include structural units represented by the following formulas (1-1) to (1-8).

In the above formula, R ^p1 has the same ^meaning as the above formula (1).

  Among these, the structural units represented by the above formulas (1-1) to (1-4) are preferable.

  Examples of the monomer compound that gives the structural unit represented by the above formula (1) include a compound represented by the following formula (1 ′).

In said formula (1 '), R < ^p2 >, Rf, n, and M ^<+> are synonymous with said formula (1).

  The compound represented by the above formula (1 ') can be synthesized by a known method.

  Examples of the compound represented by the above formula (1 ′) include compounds represented by the following formulas (1′-1) to (1′-8).

  [A] In the polymer, the content ratio of the structural unit (I) is preferably 1 mol% or more and 50 mol% or less, and preferably 1 mol% or more and 30 mol% with respect to all the structural units constituting the [A] polymer. % Or less is more preferable, and 1 mol% or more and 10 mol% or less is more preferable. If the content ratio of the structural unit (I) exceeds 50 mol%, the pattern formability may be lowered. On the other hand, when the amount is less than 1 mol%, the developer insolubility of the exposed portion becomes insufficient, and a good pattern may not be obtained. In addition, the [A] polymer may have 1 type, or 2 or more types of structural units (I).

[Structural unit (II)]
The structural unit (II) is represented by the above formula (2).

In said formula (2), ^Rp3 is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or a C1-C3 alkyl group. R ^p4 , R ^p5 and R ^p6 are each independently an organic group having 1 to 10 carbon atoms. m is an integer of 0-3. When m is 2 or 3, the plurality of R ^p4 may be the same or different from each other. A is a single bond, an alkanediyl group having 1 to 10 carbon atoms, an alkyleneoxy group having 2 to 10 carbon atoms, or an arylene group having 6 to 10 carbon atoms.
X ⁻ is a sulfonate anion, a carboxylate anion or an amide anion.

In said formula (2), a methyl group, an ethyl group, and a propyl group are mentioned as a C1-C3 alkyl group represented by ^Rp3 . Of these, a methyl group is preferable. R ^p3 is preferably a hydrogen atom or a methyl group.

  Examples of the alkanediyl group having 1 to 10 carbon atoms represented by A include, for example, a methylene group, an ethylene group, a 1,3-propylene group, a 1,2-propylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. Group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1 -Methyl-1,4-butylene group, 2-methyl-1,4-butylene group and the like.

  Examples of the alkyleneoxy group having 2 to 10 carbon atoms represented by A include an ethyleneoxy group, a 1,3-propyleneoxy group, a 1,2-propyleneoxy group, a tetramethyleneoxy group, a pentamethyleneoxy group, Hexamethyleneoxy group, heptamethyleneoxy group, octamethyleneoxy group, nonamethyleneoxy group, decamethyleneoxy group, 1-methyl-1,3-propyleneoxy group, 2-methyl-1,3-propyleneoxy group, 2 -Methyl-1,2-propyleneoxy group, 1-methyl-1,4-butyleneoxy group, 2-methyl-1,4-butyleneoxy group and the like.

  As a C6-C10 arylene group represented by said A, a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group etc. are mentioned, for example.

  Of these, alkyleneoxy groups such as an ethyleneoxy group and a propyleneoxy group are preferable from the viewpoint of excellent stability as a compound.

As a C1-C10 monovalent organic group represented by said ^Rp4 , ^Rp5, and ^Rp6 , a C1-C10 alkyl group, an alkoxy group, an aryl group etc. are mentioned, for example.

  Examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, pentyl group, and hexyl. Group, hydroxymethyl group, hydroxyethyl group, trifluoromethyl group.

  Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group, and n-pentyloxy. Group, neopentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group and the like.

  Examples of the aryl group include a phenyl group and a naphthyl group.

Among the monovalent organic groups, R ^p4 is preferably an alkoxy group, and more preferably a methoxy group. R ^p5 and R ^p6 are preferably an aryl group, more preferably a phenyl group and a naphthyl group, and still more preferably a phenyl group.

  As m, 0 and 1 are preferable and 0 is more preferable.

As said X < ^- >, a sulfonate anion and a carboxylate anion are preferable and a sulfonate anion is more preferable. Of these, the sulfonate anion represented by the above formula (5) is more preferable.

In the above formula (5), R ^p13 is a monovalent organic group having a fluorine atom.

Examples of the monovalent organic group in the monovalent organic group having a fluorine atom represented by R ^p13 include a chain alkyl group having 1 to 10 carbon atoms and an alicyclic skeleton having 6 to 20 carbon atoms. A hydrocarbon group etc. are mentioned. In addition, —O—, —S—, —C (O) O—, or —C (O) N— is present between the carbon-carbon bonds of the hydrocarbon group having a chain alkyl group and an alicyclic skeleton. You may do it. Part or all of the hydrogen atoms of the monovalent organic group having a fluorine atom are an alkyl group, an aryl group, an aralkyl group, a cycloalkyl group, a halogenated alkyl group, a halogenated aryl group, a halogenated aralkyl group, an oxidation group. It may be substituted with a cycloalkyl group, a halogenated cycloalkyl group or the like.

Examples of the C1-C10 chain alkyl group having a fluorine atom represented by R ^p13 include, for example, a trifluoromethyl group, a trifluoroethyl group, a pentafluoropropyl group, a hexafluoroisopropyl group, a hexafluoro (2 -Methyl) isopropyl group, heptafluorobutyl group, heptafluoroisopropyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluorobutyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, etc. Is mentioned. Of these, a nonafluorobutyl group is preferred.

As a hydrocarbon group which has a C6-C20 alicyclic skeleton which has a fluorine atom represented by said ^Rp13 , group represented by a following formula is mentioned, for example.

-O-, -S-, -C (O) O- between the carbon-carbon bonds of the chain alkyl group having a fluorine atom represented by R ^p13 and the hydrocarbon group having an alicyclic skeleton, or As group which has -C (O) N-, group represented by a following formula is mentioned, for example.

  Examples of the sulfonate anion represented by the above formula (5) include sulfonate anions represented by the following formulas (5-1) to (5-17).

  Among these, the sulfonate anion represented by the above formula (5-1) is preferable.

  Examples of the structural unit (II) represented by the above formula (2) include structural units represented by the following formulas (2-1) to (2-18).

In the above formula, R ^p3 has the same ^{meaning as} in the above formula (2).

  Among these, structural units represented by the above formulas (2-3), (2-10), (2-11) and (2-12) are preferable.

  Examples of the monomer compound that gives the structural unit represented by the formula (2) include compounds represented by the following formula (2 ′).

In the above formula (2 ′), A, R ^p4 , R ^p5 , R ^p6 , m and X ⁻ are as defined in the above formula (2).

  Examples of the compound represented by the above formula (2 ′) include compounds represented by the following formulas (2′-1) to (2′-18).

  [A] In the polymer, the content ratio of the structural unit (II) is preferably 1 mol% or more and 50 mol% or less, and preferably 1 mol% or more and 30 mol% with respect to all the structural units constituting the [A] polymer. % Or less is more preferable, and 1 mol% or more and 10 mol% or less is more preferable. If the content ratio of the structural unit (II) exceeds 50 mol%, the pattern formability may be lowered. On the other hand, when the amount is less than 1 mol%, the developer insolubility of the exposed portion becomes insufficient, and a good pattern may not be obtained. In addition, the [A] polymer may have 1 type, or 2 or more types of structural units (II).

[Structural unit (III)]
[A] The polymer preferably further contains the structural unit (III) represented by the above formula (6). The structural unit (III) represented by the above formula (6) is a structural unit having an acid dissociable group in which the carbon atom bonded to the ester group is a tertiary carbon and is easily dissociated by the action of an acid.

In Formula (6), R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ^{2 to} R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or an alicyclic group having 4 to 20 carbon atoms. However, R ³ and R ⁴ may be bonded to each other to form a divalent alicyclic group having 4 to 20 carbon atoms together with the carbon atom to which they are bonded.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ^{2 to} R ⁴ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, Examples include 1-methylpropyl group and t-butyl group.

C 4-20 alicyclic group represented by R ^{2 to} R ⁴ , or R ³ and R ⁴ may be bonded to each other and formed together with the carbon atoms to which they are bonded. As the alicyclic group of 4 to 20, a polycyclic alicyclic group having a bridged skeleton such as an adamantane skeleton or a norbornane skeleton; a monocyclic alicyclic group having a cycloalkane skeleton such as cyclopentane or cyclohexane Is mentioned. Among these, an alicyclic group having 10 or less carbon atoms constituting the ring is preferable. In addition, these groups may be substituted with one or more linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms, for example.

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

In said formula, R < ¹ > is synonymous with the said Formula (6). R ² is an alkyl group having 1 to 4 carbon atoms. m is an integer of 1-6.

  Among these, structural units represented by the following formulas (6-1) to (6-18) are preferable, and (6-3) is more preferable.

In said formula, R < ¹ > is synonymous with the said Formula (6).

  [A] In the polymer, the content ratio of the structural unit (III) is preferably 10 mol% or more and 80 mol% or less, and 20 mol% or more and 60 mol% with respect to all the structural units constituting the [A] polymer. % Or less is more preferable. When the content rate of structural unit (III) exceeds 80 mol%, MEEF performance, DOF, and LWR may become insufficient. On the other hand, if it is less than 10 mol%, a good pattern may not be obtained. In addition, the [A] polymer may have 1 type, or 2 or more types of structural units (III).

Examples of the monomer that gives the structural unit (III) include (meth) acrylic acid-bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-bicyclo [2.2.2] octa. 2-yl ester, (meth) acrylic acid-tricyclo [5.2.1.0 ^2,6 ] dec-7-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 Deca-1-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] dec-2-yl ester, and the like.

[Structural unit (IV)]
[A] The polymer preferably has a structural unit (IV) having at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure as another structural unit other than the above. [A] When the polymer has the structural unit (IV), the adhesion of the photoresist composition to the substrate or the like is improved.

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

In the above formula, R ⁵ is a hydrogen atom or a methyl group. R ⁶ is a hydrogen atom or a methyl group. R ⁷ and R ⁸ are each independently a hydrogen atom or a methoxy group. Z ₁ is a single bond, a methylene group, an ester group or a group formed by combining these. Z ₂ is a methylene group or an oxygen atom. b, d and e are 0 or 1;

  As the structural unit (IV), specifically, a structural unit represented by the following formula is preferable.

In the above formula, R ⁵ is a hydrogen atom or a methyl group.

  [A] In the polymer, the content ratio of the structural unit (IV) is preferably 0 mol% or more and 70 mol% or less, and preferably 10 mol% or more and 60 mol% with respect to all the structural units constituting the [A] polymer. % Or less is more preferable. By setting the content ratio of the structural unit (IV) to such a content rate, the adhesion of the photoresist composition to a substrate or the like can be improved. On the other hand, when the content rate of structural unit (IV) exceeds 70 mol%, MEEF performance, DOF, and LWR may be insufficient.

  As a preferable monomer which gives structural unit (IV), the monomer as described in an international publication 2007/116664 pamphlet is mentioned, for example.

[Structural unit (V)]
[A] The polymer may further have a structural unit (V) containing a polar group represented by the following formula. Examples of the “polar group” herein include a hydroxyl group, a carboxyl group, a keto group, a sulfonamide group, an amino group, an amide group, and a cyano group.

  Examples of the structural unit (V) include structural units represented by the following formula.

In the above formula, R ⁹ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

  [A] In the polymer, the content ratio of the structural unit (V) is preferably 5 mol% or more and 80 mol or less, and preferably 5 mol% or more and 40 mol% with respect to all the structural units constituting the [A] polymer. The following is more preferable. In addition, the [A] polymer may have 1 type, or 2 or more types of structural units (V).

[Structural unit (VI)]
[A] The polymer may contain another structural unit (VI) derived from an aromatic compound as another structural unit. Examples of the structural unit (VI) include a structural unit represented by the following formula.

In the above formula, R ^10a is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In the formula (p-1) and the formula (p-2), R ^p1 is a monovalent acid dissociable group, and R ^p2 is a monovalent hydrocarbon group which may be substituted. ka is an integer of 1 to 3, kb is an integer of 0 to 4, and ka + kb ≦ 5. However, when ka is 2 to 3, R ^p1 satisfies the above definition independently of each other, and when kb is 2 to 4, R ^p2 satisfies the above definition independently of each other. R ^10b is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In the formula (p-1) and the formula (p-2), examples of the monovalent acid dissociable group for R ^p1 include a 1-branched alkyl group, a triorganosilyl group, a triorganogermyl group, an alkoxy group. Examples thereof include a carbonyl group, an acyl group, a monovalent heterocyclic group, an alkoxyalkyl group, and a benzyl group which may be substituted. Among these, as R ^p1 , tert-butyl group, benzyl group, 1-methoxyethyl group, 1-ethoxyethyl group, 1-phenoxyethyl group, 1-adamantanoxymethyl group, trimethylsilyl group, tert-butoxycarbonyl group , Tert-butoxycarbonylmethyl group, tetrahydrofuranyl group, tetrahydropyranyl group, tetrahydrothiofuranyl group, tetrahydrothiopyranyl group and the like are preferable.

In the benzene rings in the above formula (p-1) and the above formula (p-2), the bonding position of R ^p1 is not particularly limited, but is preferably the 4-position. Also, if the benzene ring has a plurality of R ^p1, a combination of coupling positions of R ^p1 is optional. Examples of the monovalent hydrocarbon group for R ^p2 include a monovalent aliphatic hydrocarbon group, a monovalent alicyclic hydrocarbon group, and a monovalent aromatic hydrocarbon group. Examples of the monovalent aliphatic hydrocarbon group include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an alkynyl group having 2 to 20 carbon atoms. As monovalent alicyclic hydrocarbon, a C3-C20 cycloalkyl group is mentioned, for example. Examples of the monovalent aromatic hydrocarbon group include an aryl group having 6 to 20 carbon atoms. Examples of the substituent for the monovalent hydrocarbon group in R ^p2 include a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, a halogenated hydrocarbon group, an alkyl group, an alkoxyl group, an amino group, a thiol group, and an organic group. a sulfonyl group (RSO ₂ -) and the like.

  ka is an integer of 1 to 3, preferably an integer of 1 or 2. kb is an integer of 0 to 4, preferably an integer of 0 to 3, and more preferably 0 or 1.

  Specific examples of particularly preferable structural unit (VI) include 4-hydroxystyrene, 4-tert-butoxystyrene, 4- (2-ethyl-2-propoxy) styrene, 4- (1-ethoxy) styrene, tert- Examples include structural units formed by cleavage of ethylenically unsaturated bonds in butoxycarbonylstyrene, tert-butoxycarbonylmethylenestyrene, and the like.

  Preferred monomers for generating the structural unit (VI) derived from the aromatic compound include, for example, styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, and 2-methoxystyrene. 3-methoxystyrene, 4-methoxystyrene, 4- (2-t-butoxycarbonylethyloxy) styrene 2-hydroxystyrene, 3-hydroxystyrene, 4-hydroxystyrene, 2-hydroxy-α-methylstyrene, 3- Hydroxy-α-methylstyrene, 4-hydroxy-α-methylstyrene, 2-methyl-3-hydroxystyrene, 4-methyl-3-hydroxystyrene, 5-methyl-3-hydroxystyrene, 2-methyl-4-hydroxy Styrene, 3-methyl-4-hydroxystyrene, 3,4-dihi Loxystyrene, 2,4,6-trihydroxystyrene, 4-t-butoxystyrene, 4-t-butoxy-α-methylstyrene, 4- (2-ethyl-2-propoxy) styrene, 4- (2-ethyl) -2-propoxy) -α-methylstyrene, 4- (1-ethoxyethoxy) styrene, 4- (1-ethoxyethoxy) -α-methylstyrene, phenyl (meth) acrylate, benzyl (meth) acrylate, acenaphthylene , 5-hydroxyacenaphthylene, 1-vinylnaphthalene, 2-vinylnaphthalene, 2-hydroxy-6-vinylnaphthalene, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, 1-naphthylmethyl (meth) Acrylate, 1-anthryl (meth) acrylate, 2-anthryl (meth) acrylate, Examples include 9-anthryl (meth) acrylate, 9-anthrylmethyl (meth) acrylate, and 1-vinylpyrene.

  [A] In the polymer, the content ratio of the structural unit (VI) is preferably 5 mol% or more and 50 mol% or less, and preferably 10 mol% or more and 30 mol% with respect to all the structural units constituting the [A] polymer. % Or less is more preferable. In addition, the [A] polymer may have 1 type, or 2 or more types of structural units (VI).

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized according to a conventional method such as radical polymerization. For example,
A method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction;
A method in which a solution containing a monomer and a solution containing a radical initiator are separately dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction;
A plurality of types of solutions containing each monomer and a solution containing a radical initiator are separately added to a reaction solvent or a solution containing a monomer and synthesized by a method such as a polymerization reaction. be able to.

  [A] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is not particularly limited, but is preferably 1,000 or more and 500,000 or less, more preferably 2,000 or more and 400,000 or less. Preferably, it is 3,000 or more and 300,000 or less. In addition, when the Mw of the [A] polymer is less than 1,000, the heat resistance when used as a resist tends to decrease. On the other hand, when the Mw of the [A] polymer exceeds 500,000, the developability when used as a resist tends to be lowered.

  [A] The ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is usually from 1 to 5, preferably from 1 to 3, preferably from 1 to 2. More preferred. By setting Mw / Mn in such a range, the photoresist film has excellent resolution performance.

  Mw and Mn in this specification are GPC columns (Tosoh Corporation, 2 G2000HXL, 1 G3000HXL, 1 G4000HXL), with a flow rate of 1.0 mL / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. under analysis conditions. The value measured by GPC using monodisperse polystyrene as a standard.

<[B] Acid generator>
[B] The acid generator has at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, a sultone structure, and an alicyclic structure. Since the photoresist composition contains the [B] acid generator having such a bulky structure, the acid diffusion length can be further shortened, so that only basic characteristics such as sensitivity and resolution can be obtained. In addition, MEEF performance, DOF and LWR are sufficiently satisfied.

[B] The acid generator preferably has a structure represented by the following formula (8).

In the above formula (8), R ¹¹ is a monovalent organic group containing a lactone structure, a cyclic carbonate structure, a sultone structure or an alicyclic structure. R ¹² is a fluorinated methylene group or a fluorinated alkylene group having 2 to 10 carbon atoms. However, the carbon atom of the fluorinated alkylene group directly bonded to SO ₃ ^— has at least one fluorine atom. X ⁺ is an onium cation.

Examples of the alicyclic structure in the monovalent organic group containing a lactone structure, a cyclic carbonate structure, a sultone structure, or an alicyclic structure represented by R ¹¹ include:
Cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, methylcyclohexane, ethylcyclohexane, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene Monocyclic alicyclic groups such as;
Bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [3.3.1.1 ^3,7 ] decane, Tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecane, norbornane, adamantane, bicyclo [2.2.1] heptene, bicyclo [2.2.2] octene, tricyclo [5.2.1.0 ^2,6 ] decene, tricyclo [3. 3.1.1 ^3,7 ] decene, tetracyclo [6.2.1.1 ^3,6 . And polycyclic alicyclic groups such as 0 ^2,7 ] dodecene.

Examples of the lactone structure, sultone structure or alicyclic structure of R ¹¹ include structures represented by the following formulas.

  Of these, norbornane, adamantane, norbornane lactone ring, and norbornane sultone ring are preferable. [B] Since the anion portion of the acid generator has these bulky groups, acid diffusion can be further suppressed. As a result, the photoresist composition can form an excellent resist pattern by MEEF, DOF and LWR.

The monovalent organic group containing the lactone structure, cyclic carbonate structure, sultone structure or alicyclic structure represented by R ¹¹ contains one or more of the lactone structure, cyclic carbonate structure, sultone structure or alicyclic structure. Can do. In addition, as the monovalent organic group including the lactone structure, cyclic carbonate structure, sultone structure or alicyclic structure represented by R ¹¹ , a group consisting only of the lactone structure, cyclic carbonate structure, sultone structure or alicyclic structure, One selected from the group consisting of a lactone structure, a cyclic carbonate structure, a sultone structure or an alicyclic structure, and a chain hydrocarbon group having 1 to 10 carbon atoms, an ether group, an ester group, a carbonyl group, an imino group and an amide group Examples include groups formed by combining the above groups.

The fluorinated methylene group represented by R ¹² and the fluorinated alkylene group having 2 to 10 carbon atoms are preferably a group represented by the following formula (9).

In said formula (9), k is an integer of 1-10. R ^f1 and R ^f2 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 4 carbon atoms. However, when k is 2 or more, the plurality of R ^f1 and R ^f2 may be the same or different. R ^f1 or R ^f2 of the carbon atom directly bonded to SO ₃ ^— is a fluorine atom. * Is SO ₃ ^- is a site that binds to.

Examples of the fluorinated alkyl group having 1 to 4 carbon atoms represented by R ^f1 and R ^f2 include a fluorinated methyl group, a fluorinated ethyl group, a fluorinated n-propyl group, a fluorinated i-propyl group, and a fluorinated group. Examples thereof include an n-butyl group and a fluorinated t-butyl group.

  The k is preferably an integer of 2 to 6.

R ^f1 and R ^f2 are preferably a hydrogen atom and a fluorine atom.

Examples of the anion represented by R ¹¹ —R ¹² —SO ₃ ^— in the above formula (8) include anions represented by the following formulas (8-1) to (8-24).

  Of these, (8-5), (8-6) and (8-16) are preferred.

In the above formula (8), examples of the onium cation represented by X ⁺ include a sulfonium cation, a thiophenium cation, an ammonium cation, a phosphonium cation, an iodonium cation, and a pyridinium cation. Among these, a sulfonium cation and a thiophenium cation are preferable, and a cation represented by the following formula (10) is more preferable. [B] By making the onium cation of the acid generator have a specific structure represented by the following formula (10), diffusion of the generated acid can be further suppressed. As a result, the photoresist composition can form an excellent resist pattern by MEEF, DOF and LWR.

In the above formula (10), R ^{13 to} R ¹⁵ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a cyclohexane having 3 to 12 carbon atoms. An alkyl group, an alkoxy group having 1 to 10 carbon atoms, an —S—R ¹⁶ group, or a group having two or more heteroatoms. R ¹⁶ is an alkyl group or an aryl group. However, one part or all part of the hydrogen atom which the said alkyl group, cycloalkyl group, alkoxy group, and aryl group have may be substituted.

Examples of the linear or branched alkyl group having 1 to 10 carbon atoms represented by R ^{13 to} R ¹⁵ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and an n-butyl group. I-butyl, n-hexyl group, i-hexyl group and the like.

As a C3-C12 cycloalkyl group represented by said R < ¹³ > -R < ¹⁵ >, a cyclopropyl group, a cyclobutyl group, a cyclohexyl group etc. are mentioned, for example.

The alkoxy group having 1 to 10 carbon atoms represented by ^R 13 ^{to R 15,} for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, pentoxy group and the like.

Examples of the alkyl group represented by the R ¹⁶ group include the same groups as those exemplified as the linear or branched alkyl group having 1 to 10 carbon atoms represented by the R ^{13 to} R ¹⁵ , The group similar to the group illustrated as a C3-C12 cycloalkyl group represented by R < ¹³ > -R < ¹⁵ >, etc. are mentioned.

Examples of the aryl group represented by the R ¹⁶ group include a phenyl group and a naphthyl group.

  Examples of the hetero atom include an oxygen atom, a sulfur atom, a nitrogen atom, and a halogen atom.

  These [B] acid generators may use 2 or more types together. [B] The amount of the acid generator used is 0.1 with respect to 100 parts by mass of the polymer [A] from the viewpoint of ensuring the sensitivity and developability of the resist coating film formed from the photoresist composition. The mass is preferably 25 parts by mass or more and more preferably 1 part by mass or more and 20 parts by mass or less.

<[C] acid diffusion controller>
The photoresist composition preferably further contains a [C] acid diffusion controller. [C] The acid diffusion control agent controls the diffusion phenomenon in the resist coating film of the acid generated from the [A] polymer and [B] acid generator by exposure, and suppresses an undesirable chemical reaction in the unexposed area. It is what has. Therefore, in addition to the [A] polymer and the [B] acid generator, the photoresist composition contains a [C] acid diffusion control agent, so that the acid diffusion length can be further shortened and the acid diffusion can be further reduced. Can be suppressed. As a result, the photoresist composition can form a resist pattern excellent in MEEF, DOF and LWR. The content of the acid diffusion control agent in the composition may be a free compound, a form incorporated as part of the polymer, or both of these forms.

  [C] Examples of the acid diffusion controller include amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and photodegradable bases.

  Examples of the amine compound include mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N, N ′, N′— Tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis ( 4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4- Aminophenyl) -2- (4-hydroxyphenyl) propane, 1 4-bis (1- (4-aminophenyl) -1-methylethyl) benzene, 1,3-bis (1- (4-aminophenyl) -1-methylethyl) benzene, bis (2-dimethylaminoethyl) Ether, bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine N, N, N ′, N ″ N ″ -pentamethyldiethylenetriamine and the like.

  Examples of amide group-containing compounds include Nt-butoxycarbonyl group-containing amino compounds, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide Benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, isocyanuric acid tris (2-hydroxyethyl) and the like.

  Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea. Etc. Of these, Nt-butoxycarbonyl group-containing amino compounds are preferred.

  Examples of the nitrogen-containing heterocyclic compound include imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4 -Methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2. 2] octane and the like.

  As a photodegradable base, the compound etc. which are represented by following formula (11) are mentioned, for example.

In said formula (11), R < ¹⁷ > -R < ¹⁹ > is respectively independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a hydroxyl group. Y ^{- is,} OH ^-, R 20 COO ^-, or ^R 20 -SO ₃ ^- is. R ²⁰ is an alkyl group, an aryl group, or an aralkyl group. However, one part or all part of the hydrogen atom which the said alkyl group, an aryl group, and an aralkyl group have may be substituted. In addition, when Y ⁻ is R ²⁰ —SO ₃ ^— , SO ₃ ^— is not directly bonded to a carbon atom having a fluorine atom.

Examples of the halogen atom represented by R ^{17 to} R ¹⁹ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the alkyl group represented by R ^{17 to} R ¹⁹ include chain alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and an i-butyl group;
Examples thereof include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, and a norbornyl group.

Examples of the alkoxy group represented by R ^{17 to} R ¹⁹ include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

Examples of the alkyl group represented by R ²⁰ include the same groups as those exemplified as the alkyl groups represented by R ^{17 to} R ¹⁹ .

  Among these, as the [C] acid diffusion controller, a photodegradable base is preferable, and among them, compounds represented by the following formulas (C-1) to (C-5) are more preferable.

  Among these, the compounds represented by the above formulas (C-1) and (C-2) are more preferable. [C] By using the above preferred compound as an acid diffusion controller, it functions more highly and can further suppress acid diffusion. As a result, the photoresist composition is superior to MEEF, DOF and LWR.

  These [C] acid diffusion control agents may be used alone or in combination of two or more. The amount of the [C] acid diffusion controller used in the photoresist composition is preferably 0.1 parts by mass or more and 25 parts by mass or less, and preferably 1 part by mass or more and 20 parts by mass with respect to 100 parts by mass of the [A] polymer. Part or less is more preferable. [C] If the amount of the acid diffusion control agent used is less than 0.1 parts by mass, the effects of the present invention may not be fully exerted, such as inconvenience that reduction of MEEF is not achieved. On the other hand, when the amount exceeds 15 parts by mass, shape deterioration due to a decrease in sensitivity of the photoresist composition and a decrease in resist transmittance may be observed.

<Solvent>
The photoresist composition usually contains a solvent. Examples of the solvent include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents, and mixed solvents thereof. Two or more of these solvents may be used in combination.

As an alcohol solvent, for example,
Methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert- Pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n- Nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, furf Alcohol, phenol, cyclohexanol, methyl cyclohexanol, 3,3,5-trimethyl cyclohexanol, benzyl alcohol, mono-alcohol solvents such as diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 -Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, and methyl-n. -Ketones such as hexyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonyl acetone, diacetone alcohol, acetophenone And system solvents.

  Examples of amide solvents include N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide. , N-methylpropionamide, N-methylpyrrolidone and the like.

  Examples of the ether solvent include diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, methoxybenzene and the like.

  Examples of the ester solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-valerolactone, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, N-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, aceto Ethyl acetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-acetate Chill ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxytriacetate Glycol, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, Examples thereof include dimethyl phthalate and diethyl phthalate.

Other solvents include, for example,
Aliphatic carbonization such as n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane, methylcyclohexane A hydrogen-based solvent;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene and n-amylnaphthalene Group hydrocarbon solvents;
And halogen-containing solvents such as dichloromethane, chloroform, chlorofluorocarbon, chlorobenzene, and dichlorobenzene.

  Of these solvents, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, and cyclohexanone are preferred.

<Other optional components>
The photoresist composition includes a fluorine atom-containing polymer, an acid generator other than the acid generator [B], an alicyclic skeleton compound, a surfactant, a sensitizer and the like as long as the effects of the present invention are not impaired. Other optional components can be contained. Hereinafter, these optional components will be described in detail. These other optional components can be used alone or in admixture of two or more. Moreover, the compounding quantity of another arbitrary component can be suitably determined according to the objective.

[Fluorine atom-containing polymer]
The photoresist composition may contain a polymer having a higher fluorine atom content than the [A] polymer. When the photoresist composition contains a fluorine atom-containing polymer, when the resist film is formed, the distribution is unevenly distributed in the vicinity of the resist film surface due to the oil-repellent characteristics of the fluorine atom-containing polymer in the film. Therefore, it is possible to prevent the acid generator, the acid diffusion controller and the like from being eluted into the immersion medium during the immersion exposure. Further, the forward contact angle between the resist film and the immersion medium can be controlled within a desired range due to the water-repellent characteristics of the fluorine atom-containing polymer, 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 a photoresist composition contains a fluorine atom containing polymer, the resist coating film suitable for an immersion exposure method can be formed.

  The fluorine-containing polymer is not particularly limited as long as it has fluorine atoms, but it is essential that the fluorine atom content (% by mass) is higher than that of the [A] polymer. [A] When the fluorine atom content is higher than that of the polymer, the degree of uneven distribution described above is further increased, and characteristics such as water repellency and elution suppression of the resulting resist coating film are improved.

  The fluorine atom-containing polymer in the present invention is formed by polymerizing one or more monomers containing a fluorine atom in the structure.

  As a monomer that gives a polymer containing a fluorine atom in its structure, a monomer containing a fluorine atom in the main chain, a monomer containing a fluorine atom in the side chain, and a fluorine atom in the main chain and the side chain Monomer.

  Examples of monomers that give a polymer containing a fluorine atom in the main chain include α-fluoroacrylate compounds, α-trifluoromethyl acrylate compounds, β-fluoroacrylate compounds, β-trifluoromethyl acrylate compounds, α, β- Examples thereof include a fluoroacrylate compound, an α, β-trifluoromethyl acrylate compound, a compound in which hydrogen at one or more vinyl sites is substituted with fluorine or a trifluoromethyl group, and the like.

  As the monomer that gives a polymer containing a fluorine atom in the side chain, for example, the side chain of an alicyclic olefin compound such as norbornene is fluorine or a fluoroalkyl group or a derivative thereof, a fluoroalkyl group of acrylic acid or methacrylic acid, Examples of the ester compound of the derivative include a fluorine atom or a fluoroalkyl group in which the side chain of one or more olefins (site not including a double bond) or a derivative thereof is used.

  Examples of the monomer that gives a polymer containing fluorine atoms in the main chain and the side chain include α-fluoroacrylic acid, β-fluoroacrylic acid, α, β-fluoroacrylic acid, α-trifluoromethylacrylic acid, Ester compounds of fluoroalkyl groups such as β-trifluoromethylacrylic acid and α, β-trifluoromethylacrylic acid and derivatives thereof, and hydrogen in one or more kinds of vinyl sites are substituted with fluorine atoms or trifluoromethyl groups A compound in which the side chain of a compound is substituted with a fluorine atom or a fluoroalkyl group or a derivative thereof, and hydrogen bonded to a double bond of one or more alicyclic olefin compounds is substituted with a fluorine atom or a trifluoromethyl group. And the side chain is a fluoroalkyl group or a derivative thereof. In addition, this alicyclic olefin compound shows the compound in which a part of ring is a double bond.

  Examples of the structural unit possessed by the fluorine atom-containing polymer include structural units represented by the following formula (hereinafter also referred to as “structural unit (VII)”).

In the above formula, R ²¹ is hydrogen, a methyl group or a trifluoromethyl group. Z is a linking group. R ²² is a linear or branched alkyl group having 1 to 6 carbon atoms containing at least one fluorine atom, a monovalent alicyclic group having 4 to 20 carbon atoms, or a derivative thereof.

  Examples of the linking group represented by Z include a single bond, an oxygen atom, a sulfur atom, a carbonyloxy group, an oxycarbonyl group, an amide group, a sulfonylamide group, and a urethane group.

  Examples of the monomer that gives the structural unit (VII) include 2- [1- (ethoxycarbonyl) -1,1-difluorobutyl] (meth) acrylic acid ester, trifluoromethyl (meth) acrylic acid ester, 2, 2,2-trifluoroethyl (meth) acrylic acid ester, perfluoroethyl (meth) acrylic acid ester, perfluoro n-propyl (meth) acrylic acid ester, perfluoro i-propyl (meth) acrylic acid ester, perfluoro n-butyl (meth) acrylic acid ester, perfluoro i-butyl (meth) acrylic acid ester, perfluoro t-butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexa Fluoropropyl) (meth) acrylic acid ester, 1- (2,2,3,3,4,4,5,5-octa Fluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic acid ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, 1- (3,3 , 4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl) (meth) acrylic acid ester, 1- (5-trifluoro) Methyl-3,3,4,4,5,6,6,6-octafluorohexyl) (meth) acrylic acid ester and the like.

  The fluorine atom-containing polymer may contain two or more structural units (VII). The content ratio of the structural unit (VII) is usually 5 mol% or more, preferably 10 mol% or more, more preferably 15 mol% or more when all the structural units in the fluorine atom-containing polymer are 100 mol%. . If the content of the structural unit (VII) is less than 5 mol%, a receding contact angle of 70 degrees or more may not be achieved, or elution of an acid generator or the like from the resist coating film may not be suppressed.

  In addition to the structural unit (VII), the fluorine atom-containing polymer is a structural unit having an acid-dissociable group, a lactone skeleton, a hydroxyl group, a carboxyl, or the like, for example, in order to control the dissolution rate in the developer, or reflected from the substrate. In order to suppress the scattering of light due to, one or more “other structural units” such as a structural unit derived from an aromatic compound can be contained.

  As the other structural unit having an acid dissociable group, the same structural unit as the structural unit exemplified in the structural unit (II) in the [A] polymer can be applied. As the other structural unit containing the lactone skeleton, a structural unit similar to the structural unit exemplified as the structural unit (IV) in the [A] polymer can be applied. As the other structural unit containing a hydroxyl group, a structural unit similar to the structural unit exemplified as the structural unit (V) in the [A] polymer can be applied. As the structural unit derived from the aromatic compound, a structural unit similar to the structural unit exemplified as the structural unit (VI) in the [A] polymer can be applied.

  The content ratio of other structural units is usually 80 mol% or less, preferably 75 mol% or less, more preferably 70 mol% or less, assuming that all the structural units in the fluorine atom-containing polymer are 100 mol%. .

  The Mw of the fluorine atom-containing polymer is preferably 1,000 or more and 50,000 or less, more preferably 1,000 or more and 30,000 or less, and particularly preferably 1,000 or more and 10,000 or less. When the Mw of the fluorine atom-containing polymer is less than 1,000, a sufficient advancing contact angle cannot be obtained. On the other hand, when Mw exceeds 50,000, the developability of the resist tends to decrease. The ratio (Mw / Mn) between Mw and Mn of the fluorine atom-containing polymer is usually 1 or more and 3 or less, preferably 1 or more and 2 or less.

  As a content rate of the fluorine atom containing polymer in the said photoresist composition, 0 mass part or more and 50 mass parts or less are preferable with respect to 100 mass parts of [A] polymers, and 0 mass part or more and 20 mass parts or less are more. Preferably, 0.5 parts by mass or more and 10 parts by mass or less are particularly preferable, and 1 part by mass or more and 8 parts by mass or less are most preferable. By making the content rate of the said fluorine atom containing polymer in the said photoresist composition into the said range, the water repellency and elution suppression property of the resist coating film surface obtained can be improved more.

[Synthesis Method of Fluorine Atom-Containing Polymer]
The fluorine atom-containing polymer can be synthesized, for example, by polymerizing monomers corresponding to predetermined respective structural units in a suitable solvent using a radical polymerization initiator.

  Examples of the solvent used for the polymerization include the same solvents as those mentioned in the method for synthesizing the polymer [A].

  As reaction temperature in the said superposition | polymerization, it is about 40 to 150 degreeC normally, and 50 to 120 degreeC is preferable. The reaction time is usually about 1 hour to 48 hours, and preferably 1 hour to 24 hours.

[[B] Acid generator other than acid generator]
The photoresist composition may contain an acid generator other than the acid generator [B] as long as the effects of the present invention are not impaired. Examples of such an acid generator include onium salt compounds other than [B] acid generators, sulfonimide compounds, halogen-containing compounds, and diazoketone compounds.

  Examples of the onium salt compound include sulfonium salts (including tetrahydrothiophenium salts), iodonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.

  Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenyl. Sulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4 -Methanesulfonylphenyl di E sulfonyl sulfonium perfluoro -n- octanesulfonate, and the like. Of these, triphenylsulfonium trifluoromethanesulfonate and triphenylsulfonium nonafluoro-n-butanesulfonate are preferable.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona. Fluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophene 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium par Fluoro-n-oct Sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octane sulfonate and the like. Of these tetrahydrothiophenium salts, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) Tetrahydrothiophenium perfluoro-n-octane sulfonate and 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butane sulfonate are preferred.

  Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4- t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, and the like. Of these iodonium salts, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate is preferred.

  Examples of the sulfonimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy) bicyclo [ 2.2.1] Hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3- Dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene -2,3-dicarboximide and the like. Of these sulfonimide compounds, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide is preferred.

  Acid generators other than these [B] acid generators may be used alone or in combination of two or more.

[Alicyclic skeleton compound]
An alicyclic skeleton compound is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of the alicyclic skeleton compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl; deoxycholic acid t-butyl, deoxycholic acid t-butoxycarbonylmethyl, Deoxycholic acid esters such as 2-ethoxyethyl deoxycholic acid; Lithocholic acid esters such as tert-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.

[Surfactant]
Surfactants are components that 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. In addition to nonionic surfactants such as stearate, the following trade names are KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), MegaFac F171, F173 (above, manufactured by Dainippon Ink & Chemicals), Fluorad FC430, FC431 ( As above, manufactured by Sumitomo 3M, Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, manufactured by Asahi Glass) ) And the like.

[Sensitizer]
The sensitizer absorbs radiation energy and transmits the energy to the [B] acid generator, thereby increasing the amount of acid produced. It has the effect of improving the “sensitivity”. Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like.

<Method for preparing photoresist composition>
The photoresist composition can be prepared, for example, by mixing [A] polymer, [B] acid generator, [C] acid diffusion controller and other optional components in a predetermined ratio in the above solvent.
The solvent is not particularly limited as long as it can dissolve or disperse the [A] polymer, [B] acid generator, [C] acid diffusion controller, and other optional components. When the photoresist composition is used, it is usually dissolved in a solvent so that the total solid content concentration is 1% by mass or more and 30% by mass or less, preferably 1.5% by mass or more and 25% by mass or less. It is prepared by filtering with a filter of about 0.2 μm.

<Method for forming resist pattern>
Using the photoresist composition of the present invention, for example, a resist pattern can be formed by the following steps.
(1) A step of forming a coating film of the photoresist composition on a substrate (hereinafter also referred to as “step (1)”),
(2) A step of irradiating at least a part of the coating film (hereinafter also referred to as “step (2)”), and (3) a step of developing the coating film irradiated with the radiation (hereinafter referred to as “step”). (3) ". Hereinafter, each process is explained in full detail.

  By using the photoresist composition, a resist pattern excellent in MEEF, DOF and LWR can be formed. Therefore, even with radiation such as KrF excimer laser, ArF excimer laser, EUV, etc., it is possible to form a fine pattern from the photoresist composition with high accuracy and stability, and further miniaturization is expected in the future. It can be suitably used for manufacturing semiconductor devices.

[Step (1)]
In this step, a photoresist composition or a solution of the photoresist composition obtained by dissolving the photoresist composition in a solvent is applied to a silicon wafer, silicon dioxide, reflection, or the like by a coating means such as spin coating, cast coating, or roll coating. The solvent in the coating film is volatilized by applying it to a predetermined film thickness on a substrate such as a wafer coated with a protective film, and in some cases pre-baking (PB) at a temperature of about 70 ° C to 160 ° C. To form a resist film.

[Step (2)]
In this step, the resist film formed in the step (1) is exposed by irradiation with radiation (in some cases through an immersion medium such as water). At this time, radiation is irradiated through a mask having a predetermined pattern. The radiation is appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams, EUV, etc. according to the line width of the target pattern. Among these, far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable, and light sources capable of forming finer patterns such as EUV (extreme ultraviolet ray, wavelength 13.5 nm) are preferred. Even if it exists, it can be used conveniently. Subsequently, it is preferable to perform post-exposure baking (PEB). This PEB makes it possible to smoothly proceed with elimination of the acid dissociable group of the [A] polymer. The heating condition of PEB can be appropriately selected depending on the composition of the photoresist composition, but is usually about 50 ° C. or higher and 180 ° C. or lower.

[Step (3)]
In this step, a resist pattern is formed by developing the exposed resist film with a developer. After development, it is common to wash with water and dry. As the developer, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyl Dimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3.0] An aqueous alkaline solution in which at least one alkaline compound such as -5-nonene is dissolved is preferable.

  In the case of performing immersion exposure, before the step (2), in order to protect the direct contact between the immersion liquid and the resist film, an immersion liquid insoluble immersion protective film is formed on the resist film. It may be provided. As the protective film for immersion, a solvent-peeling protective film that peels off with a solvent before the step (3) (see, for example, JP-A-2006-227632), a developer that peels off simultaneously with the development in the step (3) Any of peelable protective films (for example, see International Publication No. 2005-069096, International Publication No. 2006-035790, etc.) may be used.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Mw and Mn of the polymer were measured under the following conditions using GPC columns (Tosoh Corporation, 2 G2000HXL, 1 G3000HXL, 1 G4000HXL).
Column temperature: 40 ° C
Elution solvent: Dimethylformamide (LiBr 0.3% (mass conversion), H ₃ PO ₄ 0.1% (mass conversion) mixed solution)
Flow rate: 1.0 mL / min Sample concentration: 0.2% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

¹³ C-NMR analysis was measured using a nuclear magnetic resonance apparatus (JEOL Ltd., JNM-EX270).

  The residual amount of the low molecular weight component derived from the monomer was measured using an Intersil ODS-25 μm column (4.6 mmφ × 250 mm) manufactured by GL Science, a flow rate of 1.0 ml / min, an elution solvent acrylonitrile / 0.1% phosphoric acid aqueous solution. Measurement was performed by high performance liquid chromatography (HPLC) under the analysis conditions described above.

<[A] Synthesis of polymer>
The monomers used for the synthesis of the [A] polymer and the [D] fluorine atom-containing polymer described below are shown below.

[Synthesis Example 1]
Compound (M-1) 10.46 g (40 mol%), Compound (M-2) 3.5 g (10 mol%), Compound (M-3) 1.83 g (2 mol%) and Compound (M-4) ) 14.22 g (48 mol%) was dissolved in 60 g of methyl ethyl ketone, and 2.2 g of AIBN was added to prepare a monomer solution. A 500 mL three-necked flask containing 30 g of methyl ethyl ketone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization solution was put into 600 g of isopropanol / hexane mixed liquid (50 mass%: 50 mass%), and the precipitated white powder was filtered off. The filtered white powder was washed twice with 120 g of isopropanol as a slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-1) (18.6 g). Yield 62.0%). Mw of the obtained polymer (A-1) was 4,374, and Mw / Mn was 1.56. The residual amount of the low molecular weight component was 1.0%. As a result of ¹³ C-NMR analysis, the structural unit derived from the compound (M-1): the structural unit derived from the compound (M-2): the structural unit derived from the compound (M-3): derived from the compound (M-4) The content ratio of the structural unit was 42.1: 8.2: 2.2: 47.5 (mol%).

[Synthesis Examples 2 to 11]
Polymers (A-2) to (A-10) and (a-1) were obtained in the same manner as in Synthesis Example 1, except that a predetermined amount of the monomers listed in Table 1 were blended. In addition, Mw, Mw / Mn, yield (%), residual amount of low molecular weight component (%) of each polymer obtained, and the content of the structural unit derived from each monomer in each polymer are combined. Table 1 shows.

<[D] Synthesis of fluorine atom-containing polymer>
[Synthesis Example 12]
Monomer (M-11) 35.83 g (70 mol%) and monomer (M-12) 14.17 g (30 mol%) were dissolved in 2-butanone 50 g, and dimethyl 2,2 was further used as an initiator. A monomer solution in which 5.17 g (8 mol%) of '-azobis (2-methylpropionate) was charged and dissolved was prepared. Next, 50 g of 2-butanone was charged into a 500 ml three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer. Using a dropping funnel, a monomer solution prepared in advance was added dropwise over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled to 30 ° C. or less by water cooling. After cooling, the reaction solution, 150 g of hexane, 600 g of methanol, and 30 g of water were poured into a separatory funnel and stirred vigorously, and then allowed to stand. The mixed solution was separated into two layers and allowed to stand for 3 hours, and then the lower layer (resin solution) was collected. The resin solution fractionated using an evaporator was solvent-substituted with a propylene glycol monomethyl ether acetate solution. 159.2 g of a propylene glycol monomethyl ether acetate solution of the copolymer was obtained. As a result of obtaining the solid content concentration using a hot plate, the copolymer concentration was 20.1% and the yield was 64%. This copolymer was referred to as “resin (A-3)”. This copolymer had Mw of 6,900 and Mw / Mn of 1.34. As a result of ¹³ C-NMR analysis, a copolymer (D) in which the content ratio of the repeating unit derived from the compound (M-5): the repeating unit derived from the compound (M-7) is 70.5: 29.5 (mol%). -1) was obtained.

<Preparation of photoresist composition>
The [B] acid generator, [C] acid diffusion controller and solvent used in the preparation of the photoresist composition are shown below.

<[B] Acid generator>
B-1 to B-5: Compound B-6 represented by the following formula: Triphenylsulfonium nonaflate

<[C] acid diffusion controller>
C-1 to C-3: compounds represented by the following formula

<Solvent>
E-1: Propylene glycol monomethyl ether acetate E-2: Cyclohexanone E-3: γ-butyrolactone

[Example 1]
100 parts by mass of polymer (A-1), 11 parts by mass of acid generator (B-1), 5.5 parts by mass of acid diffusion controller (C-1), 3 parts by mass of polymer (D-1), solvent (E-1) 2,220 parts by mass, (E-2) 950 parts by mass, and (E-3) 30 parts by mass were mixed, and the resulting mixed solution was filtered with a filter having a pore size of 0.2 μm to obtain a photo A resist composition was prepared.

[Examples 2 to 15 and Comparative Examples 1 to 3]
A photoresist composition was prepared in the same manner as in Example 1 except that the types and amounts of each component shown in Table 2 were used.

<Evaluation using ArF excimer laser>
The following evaluation results are also shown in Table 2.

[Evaluation of sensitivity]
A film having a film thickness of 75 nm was formed from a photoresist composition on a 12-inch silicon wafer on which a lower antireflection film (ARC66, manufactured by Nissan Chemical Industries, Ltd.) was formed, and soft baking (SB) was performed at 120 ° C. for 60 seconds. Next, this film was patterned using an ArF excimer laser immersion exposure apparatus (“NSR S610C”, manufactured by NIKON) with a pattern of 46 nm lines and 92 nm pitches under the conditions of NA = 1.3, ratio = 0.800, Annular. It exposed through the mask pattern for formation. After the exposure, each photoresist composition was post-baked (PEB) at 100 ° C. for 60 seconds. Thereafter, the resist film was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution, washed with water, and dried to form a positive resist pattern. At this time, the exposure amount at which the portion exposed through the mask pattern for pattern formation of 46 nm lines and 92 nm pitches forms a line width of 46 nm was defined as the optimum exposure amount (Eop). This optimum exposure amount was defined as sensitivity (mJ / cm ² ). Note that a scanning electron microscope (Hitachi High-Technologies Corporation, CG4000) was used for length measurement. When the sensitivity was 50 (mJ / cm ² ) or less, it was evaluated as good.

[MEEF]
With the above Eop, patterns having a line width target size at a 92 nm pitch of 43 nm line, 44 nm line, 45 nm line, 46 nm line, 47 nm line, 48 nm line, 49 nm line are used to form an LS pattern with a pitch of 92 nm, The line width formed in the resist film was measured with a length measuring SEM (Hitachi, CG4000). At this time, the slope of the straight line when the target size (nm) was plotted on the horizontal axis and the line width (nm) formed on the resist film using each mask pattern was plotted on the vertical axis was calculated as MEEF. The closer the value is to 1, the better the mask reproducibility, and the lower the MEEF value, the lower the mask production cost. The results are shown in Table 2.

[Line Width Roughness (LWR)]
A line having a line width of 46 nm formed by the above Eop was observed from the upper part of the pattern using a Hitachi SEM “CG4000”, and the line width was measured at arbitrary 10 points. The 3-sigma value (variation) of the measured line width was defined as LWR (nm). If the value of this LWR was 6.2 nm or less, it was evaluated that the formed pattern shape was good.

[Depth Of Focus (DOF)]
When the pattern size resolved with a 45 nm line and 150 nm pitch is within ± 10% of the mask design size at the optimum exposure dose (Eop) in the sensitivity evaluation, DOF (nm ).

  As shown in Table 2, it was found that the photoresist composition of the present invention was excellent in sensitivity, MEEF, DOF, and LWR lithography performances.

<Evaluation by electron beam>
[Examples 18 and 19 and Comparative Example 4]
Using the photoresist compositions used in Examples 1 and 2 and Comparative Example 1, the following evaluations were performed under the conditions shown in Table 2.

[Evaluation of photoresist composition]
Each composition solution was spin-coated on a silicon wafer in “Clean Track ACT-8” manufactured by Tokyo Electron Co., Ltd., and then subjected to PB (heat treatment) under the conditions shown in Table 3 to form a resist film having a film thickness of 60 nm. Formed. Thereafter, the resist film was irradiated with an electron beam using a simple electron beam drawing apparatus (manufactured by Hitachi, Ltd., model “HL800D”, output: 50 KeV, current density: 5.0 amperes / cm ² ). After the electron beam irradiation, PEB was performed under the conditions shown in Table 3. Thereafter, using a 2.38% tetramethylammonium hydroxide aqueous solution, development was carried out at 23 ° C. for 1 minute by the paddle method, followed by washing with pure water and drying to form a resist pattern. The following items were evaluated for the resist thus formed. The evaluation results are also shown in Table 3.

(1) Sensitivity (L / S)
A pattern [a so-called line-and-space pattern (1L1S)] composed of a line portion having a line width of 150 nm and a space portion (that is, a groove) having an interval of 150 nm formed by adjacent line portions is 1: 1. The exposure amount formed in the line width was set as the optimum exposure amount, and the sensitivity was evaluated based on the optimum exposure amount. FIG. 1 is a plan view schematically showing the shape of a line and space pattern. FIG. 2 is a cross-sectional view schematically showing the shape of the line and space pattern. However, the unevenness shown in FIGS. 1 and 2 is exaggerated from the actual.

(2) Nano-edge roughness A line-and-space pattern (1L1S) with a design line width of 150 nm is scanned with a scanning electron microscope for semiconductors (high resolution FEB measuring device, trade name “S-9220”, manufactured by Hitachi, Ltd.) ). With respect to the observed shape, as shown in FIG. 1 and FIG. 2, the line width and the design line at the most conspicuous portion of the unevenness generated along the lateral surface 2a of the line part 2 of the resist film formed on the silicon wafer 1 are shown. The difference “ΔCD” from the width of 150 nm was measured by CD-SEM (manufactured by Hitachi High-Technologies Corporation, “S-9220”) to evaluate nanoedge roughness.

(3) Resolution (L / S)
For the line-and-space pattern (1L1S), the minimum line width (nm) of the line pattern resolved with the optimum exposure dose was taken as the resolution.

  According to Tables 2 and 3, the photoresist compositions of Examples 18 to 19 of the present invention are more sensitive to electron beams or extreme ultraviolet rays and have lower roughness than the photoresist composition of Comparative Example 4. In addition, it was confirmed that a chemically amplified positive resist film capable of forming a fine pattern with high precision and stability can be formed with excellent resolution.

DESCRIPTION OF SYMBOLS 1; Base material 2; Resist pattern 2a;

The photoresist composition of the present invention is suitably used in the formation of resist patterns in the lithography process of various electronic devices such as semiconductor devices and liquid crystal devices.

Claims (8)

[A] a polymer having an acid generating group, and [B] an acid generator having at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, a sultone structure, and an alicyclic structure,
[A] A photoresist composition in which the polymer contains a structural unit (I) represented by the following formula (1).

(In formula (1), R ^p1 is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ^p2 is a divalent organic group. Each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 3 carbon atoms, n is an integer of 0 to 6. M ⁺ is an onium cation represented by the following formula (4). is there.)

(In formula (4), R ^{p10 to} R ^p12 are each independently a hydroxy group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an —S—R ^x group or a group having a plurality of heteroatoms. R ^x is an alkyl group or an aryl group, provided that a part or all of the hydrogen atoms of the alkyl group, cycloalkyl group, alkoxy group and aryl group may be substituted. integer is .b and c 5 are each independently an integer of 0 to 5. However, of one or more of ^{R p10,} at least one the following formulas (4-1) or the following formula (4 -2).)
-OSO ₂ -R ^x ··· (4-1)
-SO ₂ -R ^x ··· (4-2)
(In formula (4-1), R ^x has the same meaning as in formula (4) above. In formula (4-2), R ^x represents an alkyl group, a cyclohexyl group, or an aryl group.)   [B] The photoresist composition according to claim 1, wherein the acid generator has at least one structure selected from the group consisting of a lactone structure and a sultone structure. [A] The photoresist composition according to claim 1 or 2, wherein the polymer further comprises a structural unit (II) represented by the following formula (2).

(In Formula (2), R ^p3 is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. R ^p4 , R ^p5, and R ^p6 are each independently a carbon number. It is an organic group of 1 to 10. m is an integer of 0 to 3. When m is 2 or more, a plurality of R ^p4 may be the same or different, and A is a single bond or a carbon number. 1-10 alkanediyl group, an alkylene group or an arylene group having 6 to 10 carbon atoms of 2 to 10 carbon atoms .X ^- is sulfonate anion, a carboxylate anion, or amide anion). [A] X in the above formula (2) in the polymer ^- the photoresist composition according to claim 3 represented by the following formula (5).
R ^p13 —SO ₃ ^— (5)
(In formula (5), R ^p13 is a monovalent organic group having a fluorine atom.) [A] The photoresist composition according to claim 1, wherein the polymer further comprises a structural unit (III) represented by the following formula (6).

(In the formula (6), ^{R 1} is ^.R 2 to R ⁴ a hydrogen atom, a fluorine atom, a trifluoromethyl group or an alkyl group having 1 to 3 carbon atoms are each independently 1 to 4 carbon atoms Or an alicyclic group having 4 to 20 carbon atoms, provided that R ³ and R ⁴ are bonded to each other, and the divalent fatty acid having 4 to 20 carbon atoms together with the carbon atom to which they are bonded. A cyclic group may be formed.)   [A] The polymer further comprises at least one structural unit (IV) selected from the group consisting of a structural unit having a lactone structure, a structural unit having a cyclic carbonate structure, and a structural unit having a sultone structure. The photoresist composition described in 1.   [C] The photoresist composition according to claim 1, further comprising an acid diffusion controller.   [C] The photoresist composition according to claim 7, wherein the acid diffusion controller is a photodegradable base.

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