JP5967082B2 - Photoresist composition - Google Patents

Description

  The present invention relates to a photoresist composition.

  Lithography using short-wavelength radiation typified by KrF excimer laser light (wavelength 248 nm) and ArF excimer laser light (wavelength 193 nm) in order to obtain a higher degree of integration in the field of microfabrication for manufacturing integrated circuit elements, etc. Technology is being developed. As a photoresist material adapted to these radiations, from the viewpoint of high sensitivity, high resolution, etc., a chemical amplification type containing a component having an acid dissociable group and an acid generator that generates an acid upon irradiation with radiation. This photoresist composition is widely used (see Japanese Patent Application Laid-Open No. 59-45439).

  Among such photoresist compositions, as a composition suitable for shorter wavelength ArF excimer laser light, for example, a composition containing a polymer containing an alicyclic group in the skeleton having no large absorption in the 193 nm region It has been known. As the polymer, those having a spirolactone structure have been proposed (see Japanese Patent Application Laid-Open Nos. 2002-82441 and 2002-308937). It is said that such a polymer having a spirolactone structure can improve the development contrast of a photoresist composition containing the polymer.

  However, in recent years when further device miniaturization is progressing, the performance level required for the photoresist composition is further increased, and more excellent lithography properties and the like are required. Therefore, even if a conventional photoresist composition is used, the high level requirement cannot be met. For example, a conventional photoresist composition has lithography characteristics using MEEF (Mask Error Enhancement Factor), DOF (Depth Of Focus), LWR (Line Width Roughness), etc. as indices indicating mask error tolerance. The current situation is that we cannot fully satisfy the above. In addition, there is a demand for further suppressing development defects such as bridge defects and further improving the resistance to pattern collapse of resist patterns.

  In view of such circumstances, the photoresist composition for forming a finer resist pattern has improved lithography performance using not only basic characteristics such as sensitivity and resolution but also MEEF, DOF, LWR, etc. as an index. Etc. are desired.

JP 59-45439 A JP 2002-82441 A JP 2002-308937 A

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

（式（１）中、Ｒ^０は、水素原子、フッ素原子、水酸基又は炭素数１〜２０の１価の有機基である。Ｒ^１及びＲ^２は、それぞれ独立して、水素原子、フッ素原子、水酸基若しくは炭素数１〜２０の１価の有機基であるか、又はＲ^１及びＲ^２が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３〜１０の環構造を形成している。ａは、１〜６の整数である。但し、ａが２以上の場合、複数のＲ^１及びＲ^２は、それぞれ同一でも異なっていてもよい。Ｒ^３及びＲ^４は、それぞれ独立して、水素原子、フッ素原子、水酸基若しくは炭素数１〜２０の１価の有機基であるか、又はＲ^３及びＲ^４が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３〜１０の環構造を形成している。但し、上記環構造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。また、Ｒ^０〜Ｒ^４のうち少なくともひとつはヘテロ原子を含む基である。
式（２）中、Ｒ^５は、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^６及びＲ^７は、それぞれ独立して、炭素数１〜４のアルキル基若しくは炭素数４〜２０の脂環式基であるか、又はＲ^６及びＲ^７が互いに結合してそれらが結合している炭素原子と共に２価の脂環式基を形成している。Ｒ^８は、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。上記アルキル基及び脂環式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。）The invention made to solve the above problems is
[A] Polymer component having the structural unit (I) represented by the following formula (1) and the acid dissociable group-containing structural unit (II) represented by the following formula (2) in the same or different polymers (Hereinafter also referred to as “[A] polymer component”) and [B] a photoresist composition containing an acid generator.

(In Formula (1), R ⁰ is a hydrogen atom, a fluorine atom, a hydroxyl group, or a monovalent organic group having 1 to 20 carbon atoms. R ¹ and R ² are each independently a hydrogen atom or a fluorine atom. A hydroxyl group or a monovalent organic group having 1 to 20 carbon atoms, or R ¹ and R ² are bonded to each other to form a ring structure having 3 to 10 carbon atoms together with the carbon atom to which they are bonded. A is an integer of 1 to 6. However, when a is 2 or more, a plurality of R ¹ and R ² may be the same or different, and R ³ and R ⁴ are each independently And a hydrogen atom, a fluorine atom, a hydroxyl group, or a monovalent organic group having 1 to 20 carbon atoms, or R ³ and R ⁴ are bonded to each other and have 3 to 10 carbon atoms together with the carbon atom to which they are bonded. Provided that one of the hydrogen atoms contained in the ring structure is Or all may be substituted. In addition, at least one of R ⁰ to R ⁴ is a group containing a hetero atom.
In formula (2), R ⁵ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁶ and R ⁷ are each independently an alkyl group having 1 to 4 carbon atoms or an alicyclic group having 4 to 20 carbon atoms, or R ⁶ and R ⁷ are bonded to each other. A divalent alicyclic group is formed together with the carbon atom. R ⁸ is an alkyl group having 1 to 4 carbon atoms or an alicyclic group having 4 to 20 carbon atoms. Some or all of the hydrogen atoms of the alkyl group and alicyclic group may be substituted. )

  The photoresist composition has a structural unit (I) containing a lactone structure represented by the above formula (1) and an acid dissociable group-containing structural unit (II) represented by the above formula (2) [ A] Since the polymer component is contained, the lithography performance using MEEF, LWR, DOF, etc. as an index is excellent.

  [A] The polymer component preferably contains at least one selected from the group consisting of structural units represented by the following formulas (2A) to (2C) as the structural unit (II).

（式（２Ａ）〜（２Ｃ）中、Ｒ^５は、上記式（２）と同義である。Ｒ^Ａは、それぞれ独立して、炭素数１〜４のアルキル基である。ｍ１及びｍ２は、それぞれ独立して、１〜６の整数である。）

(In the formulas (2A) to (2C), R ⁵ has the same meaning as the above formula (2). Each R ^A is independently an alkyl group having 1 to 4 carbon atoms. Each is independently an integer of 1 to 6.)

  [A] When the polymer component contains the specific structural unit as the structural unit (II), the photoresist composition maintains an improvement in lithography performance using the MEEF, LWR, DOF, etc. as an index. However, the occurrence of bridge defects can be suppressed.

  [A] The polymer component preferably further contains at least one selected from the group consisting of structural units represented by the following formulas (2D) to (2I) as the structural unit (II).

（式（２Ｄ）〜（２Ｉ）中、Ｒ^５は、上記式（２）と同義である。Ｒ^Ａは、上記式（２Ａ）〜（２Ｃ）と同義である。Ｒ^Ｂは、それぞれ独立して、炭素数１〜４のアルキル基である。）

(In the formula (2D) ~ (2I), R 5 is as defined in the above formula (2) .R ^A is as defined in the above formula (2A) ~ (2C) .R B are each independently And an alkyl group having 1 to 4 carbon atoms.)

  [A] When the polymer component further includes the specific structural unit as the structural unit (II), the photoresist composition maintains an improvement in lithography performance using the MEEF, LWR, DOF, etc. as an index. However, the occurrence of bridge defects can be suppressed and the resistance to pattern collapse of the resist pattern can be enhanced.

  [A] It is preferable that the polymer component further has a structural unit (III) which is a structural unit other than the structural unit (I) and the structural unit (II) and contains a polar group. Since the [A] polymer component further has the structural unit (III) containing a polar group, the compatibility between the [A] polymer component and other components such as the [B] acid generator is improved. The said photoresist composition can make the lithography performance which used MEEF, LWR, DOF etc. as a parameter | index more excellent.

  [A] It is preferable that the polymer component further has at least one group (a) selected from the group consisting of a lactone group, a cyclic carbonate group and a sultone group. [A] When the polymer component further has the specific group (a), the photoresist composition can further improve lithography performance using MEEF, LWR, DOF, etc. as an index.

  The group (a) is preferably contained in a structural unit (IV) other than the structural unit (I). By including the group (a) in the structural unit (IV), the photoresist composition can further improve the lithography performance using MEEF, LWR, DOF, etc. as an index.

  The group (a) is also preferably contained in the structural unit (I). Even when the group (a) is contained in the structural unit (I), the photoresist composition can further improve the lithography performance using MEEF, LWR, DOF, etc. as an index.

  It is preferable that the acid dissociable group contained in the structural unit (II) has 4 to 9 carbon atoms. By using the acid dissociable group contained in the structural unit (II) as a group having a relatively small number of carbon atoms, the photoresist composition particularly improves lithography performance using MEEF, LWR, DOF, etc. as an index. be able to.

  [A] The total content of the structural unit (I) and the structural unit (II) in the polymer component is 20 mol% to 70 mol%, and the content of the structural unit (I) is 5 mol% to 60 mol. It is preferable that it is below mol%. [A] By setting the content of the structural units (I) and (II) in the polymer component within the specific range, the photoresist composition can be used in addition to basic performance such as sensitivity, MEEF, LWR, DOF. Lithographic performance can be particularly improved using the above as an index.

In addition, the content rate of the structural unit in the [A] polymer component is obtained by measuring the ¹³ C-NMR spectrum of the [A] polymer component, and from the area ratio of the peak corresponding to each structural unit in the obtained spectrum, [ A] It can obtain | require as an average value in a polymer component.

  As described above, the photoresist composition of the present invention contains the [A] polymer component having the structural unit (I) containing a specific lactone structure and the acid dissociable group-containing structural unit (II). Therefore, in addition to basic characteristics such as sensitivity, the lithography performance using MEEF, LWR, DOF, etc. as an index is excellent. Therefore, a fine pattern can be formed with high accuracy by using the photoresist composition.

<Photoresist composition>
The photoresist composition contains a [A] polymer component and a [B] acid generator. Moreover, you may contain another component, unless the effect of this invention is impaired. Hereinafter, each component will be described in detail.

<[A] Polymer component>
[A] The polymer component is a structural unit (I) represented by the above formula (1) and an acid dissociable group-containing structural unit (II) represented by the above formula (2) in the same or different polymers. It is a polymer component having By containing the [A] polymer component, the photoresist composition satisfies basic characteristics such as sensitivity, and is excellent in lithography performance with MEEF, LWR, DOF, etc. as an index.

The [A] polymer component is a copolymer of a plurality of types of monomer compounds such as a monomer compound that provides the structural unit (I) and a monomer compound that provides the structural unit (II). Or two or more polymers obtained by blending a plurality of polymers such as a polymer of a monomer compound that gives the structural unit (I) and a polymer of the monomer compound that gives the structural unit (II). The component may be included. [A] The polymer component preferably has a structural unit (III) containing a polar group in addition to the structural unit (I) and the structural unit (II). [A] The polymer component preferably further has at least one group (a) selected from the group consisting of a lactone group, a cyclic carbonate group and a sultone group. This group (a) may be contained in the structural unit (I), may be contained in a structural unit (IV) other than the structural unit (I), or may be contained in both of the above. Also good. [A] When the polymer component has the group (a), the photoresist composition can improve lithography performance with MEEF, LWR, DOF, etc. as an index. Furthermore, you may have another structural unit, unless the effect of this invention is impaired. In addition, when the said photoresist composition contains the below-mentioned [F] polymer, it is preferable that the polymer containing the structural unit (II) in a [A] polymer component does not contain a fluorine atom.
Hereinafter, each structural unit will be described in detail.

[Structural unit (I)]
The structural unit (I) is represented by the above formula (1). [A] Since the polymer component has a structural unit (I) containing a specific lactone structure directly connected to the polymer main chain, the photoresist composition is excellent in lithography performance with MEEF, DOF and LWR as indices. .

In said formula (1), ^R0 is a hydrogen atom, a fluorine atom, a hydroxyl group, or a C1-C20 monovalent organic group. R ¹ and R ² are each independently a hydrogen atom, a fluorine atom, a hydroxyl group, or a monovalent organic group having 1 to 20 carbon atoms, or R ¹ and R ² are bonded to each other. A ring structure having 3 to 10 carbon atoms is formed together with the carbon atoms. a is an integer of 1-6. However, when a is 2 or more, the plurality of R ¹ and R ² may be the same or different. R ³ and R ⁴ are each independently a hydrogen atom, a fluorine atom, a hydroxyl group or a monovalent organic group having 1 to 20 carbon atoms, or R ³ and R ⁴ are bonded to each other. A ring structure having 3 to 10 carbon atoms is formed together with the carbon atoms. However, one part or all part of the hydrogen atom which the said ring structure has may be substituted. In addition, at least one of R ^{0 to} R ⁴ is a group containing a hetero atom.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the above R ^{0 to} R ⁴ include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, Examples thereof include aromatic hydrocarbon groups having 6 to 20 carbon atoms, heterocyclic groups having 3 to 10 nucleus atoms, epoxy groups, cyano groups, carboxy groups, and groups represented by -R'-QR ". However, R ′ is a single bond or a hydrocarbon group having 1 to 20 carbon atoms. R ″ is an optionally substituted hydrocarbon group having 1 to 20 carbon atoms. Q is —O—, —CO—, —NH—, —SO ₂ —, —SO— or a combination thereof. Part or all of the hydrogen atoms of the chain hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group are substituted with halogen atoms such as fluorine atoms, cyano groups, carboxy groups, hydroxyl groups, thiol groups, etc. May be.

  Examples of the chain hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, and a decyl group. Among these, a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group are preferable, and a methyl group and an ethyl group are more preferable.

  Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic alicyclic hydrocarbon groups such as cyclopropyl group, cyclobutyl group, cyclohexyl group, cyclooctyl group, and cyclodecyl group; norbornyl group And a polycyclic alicyclic hydrocarbon group such as an adamantyl group.

  As said C6-C20 aromatic hydrocarbon group, a phenyl group, a naphthyl group, etc. are mentioned, for example.

  Examples of the heterocyclic group having 3 to 10 nuclear atoms include a lactone group, a cyclic carbonate group, a sultone group, a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, and a pyridine ring. And a group to be included. Of these, a lactone group, a cyclic carbonate group, and a sultone group are preferable, a lactone group is more preferable, and a butyrolactone group is more preferable.

Examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R ′ and R ″ in —R′—QR ″ include, for example, a chain hydrocarbon group having 1 to 20 carbon atoms and 3 to 20 carbon atoms. And an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and the like. For each include the same groups as the groups exemplified in the monovalent organic group having 1 to 20 carbon atoms represented by R ⁰ to R ^4.

R ¹ and R ² are bonded together and the ring structure formed with the carbon atom to which they are bonded, and R ³ and R ⁴ are bonded together and formed with the carbon atom to which they are bonded. Examples of the group having a ring structure having 3 to 10 carbon atoms include alicyclic groups such as cyclopropanediyl group, cyclohexanediyl group, norbornanediyl group and adamantanediyl group, oxygen atom, sulfur atom, nitrogen atom and the like. Examples include heterocyclic groups containing a hetero atom. Of these, the cycloaliphatic group is preferably a cyclopentanediyl group, cyclohexanediyl group or adamantanediyl group, and the heterocyclic group is preferably a cyclic ether group, a lactone group or a sultone group.

The hetero atom contained in at least one of R ^{0 to} R ⁴ is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, but an oxygen atom, a nitrogen atom, a sulfur atom, an iodine atom, and a halogen atom are preferable. An oxygen atom and a fluorine atom are more preferable, and an oxygen atom is still more preferable.

In the above formula (1), a is preferably ¹ , and R ¹ is preferably a hydrogen atom.

  Examples of the structural unit (I) include structural units represented by the following formulas (1-1) to (1-79). Among these, structural units further containing a lactone structure other than the lactone structure directly connected to the polymer main chain include the following formulas (1-7), (1-8), (1-68), (1-70). ), (1-72), (1-73) and the structural unit represented by (1-76) include the following formulas (1-74) and (1-77) as structural units containing a cyclic carbonate structure: Examples of the structural unit in which the structural unit represented by (1-79) includes a sultone structure include structural units represented by the following formulas (1-75) and (1-78).

Of these, at least one group of R ³ and R ⁴ are structural units, structural units in which at least one group of R ³ and R ⁴ is a cyclic organic group, R ³ and R ⁴ are bonded to an oxygen atom And a structural unit that forms a ring structure with the carbon atom to which they are bonded. Among them, the above formulas (1-1) to (1-9), (1-12) to (1-21), (1-25) to (1-47), (1-55) to (1-67) ), (1-69) to (1-79) are more preferred, and (1-1), (1-17), (1-19), (1-70) to (1-70) are preferred. 79) is more preferred.

  [A] In the polymer component, the content of the structural unit (I) is preferably 1 mol% or more and 80 mol% or less, and preferably 5 mol% or more and 60 mol% with respect to all the structural units constituting the [A] polymer component. The mol% or less is more preferable. By making the content rate of structural unit (I) into the said range, the lithography performance which used MEEF, LWR, DOF etc. as a parameter | index can be improved effectively. In addition, the [A] polymer component may have 1 type, or 2 or more types of structural units (I).

  As a monomer which gives structural unit (I), the compound represented by a following formula is mentioned, for example.

  The monomer giving the structural unit (I) can be produced, for example, by the following method.

  2-methyltetrahydrofuran-3-one (compound a) and ethyl (2-bromomethyl) acrylate (compound b) dissolved in THF were added dropwise to a tetrahydrofuran (THF) solvent to which zinc powder was added as a catalyst. Then, by stirring at room temperature, the compound a and the compound b react to produce 6-methyl-3-methylene-1,7-dioxaspiro [4,4] nonan-2-one (the above formula (1-1) Is synthesized). An activator such as chlorotrimethylsilane may be added to the THF solvent to which zinc powder has been added before adding the compounds a and b. Moreover, in compounds other than the compound represented by Formula (1-1), it is compoundable similarly by changing the compound a suitably.

[Structural unit (II)]
[A] The polymer component has the structural unit (II) together with the structural unit (I). Since the structural unit (II) represented by the above formula (2) has an acid dissociable group that is easily dissociated by the action of an acid generated from the [B] acid generator upon exposure, the photoresist composition [A] Having the structural unit (II) in the polymer component sufficiently satisfies the basic characteristics such as sensitivity, and can form a resist pattern that is superior in lithography performance with MEEF, DOF, LWR, etc. as an index. It becomes possible.

The structural unit (II) is represented by the above formula (2). In the above formula (2), R ⁵ represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁶ and R ⁷ are each independently an alkyl group having 1 to 4 carbon atoms or an alicyclic group having 4 to 20 carbon atoms, or R ⁶ and R ⁷ are bonded to each other. A divalent alicyclic group is formed together with the carbon atom. R ⁸ is an alkyl group having 1 to 4 carbon atoms or an alicyclic group having 4 to 20 carbon atoms. Some or all of the hydrogen atoms of the alkyl group and alicyclic group may be substituted.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ^{6 to} R ⁸ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and a tert-butyl group. , 2-methylpropyl group, 1-methylpropyl group and the like.

Examples of the alicyclic group having 4 to 20 carbon atoms represented by R ^{6 to} R ^{8 and} the alicyclic group formed together with the carbon atoms to which R ⁶ and R ⁷ are bonded to each other are as follows: Examples thereof include polycyclic alicyclic groups having a bridged skeleton such as an adamantane skeleton and norbornane skeleton; and monocyclic alicyclic groups having a cycloalkane skeleton such as cyclopentane and cyclohexane. 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.

  As the structural unit (II), structural units represented by the following formulas (2A) to (2I) are preferable.

In the above formulas (2A) to (2I), R ⁵ has the same meaning as the above formula (2). Each R ^A is independently an alkyl group having 1 to 4 carbon atoms. m1 and m2 are each independently an integer of 1 to 6. R ^B is each independently an alkyl group having 1 to 4 carbon atoms.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ^A and R ^B include the same groups as those exemplified as the alkyl group having 1 to 4 carbon atoms represented by R ^{6 to} R ⁸ .

  [A] The polymer component is at least one selected from the group consisting of structural units represented by the above formulas (2A) to (2C) as the structural unit (II) (hereinafter referred to as “structural unit (II-1)”). In addition to the structural unit (II-1), at least one selected from the group consisting of structural units represented by the above formulas (2D) to (2I) (hereinafter referred to as “structure”). It is more preferable to further include a unit (II-2) ”. [A] When the polymer component contains the structural unit (II-1) as the structural unit (II), it is possible to suppress the occurrence of bridge defects while maintaining the improvement of the lithography performance. In addition to this, the [A] polymer component further includes the structural unit (II-2) as the structural unit (II), whereby the resistance to pattern collapse of the resist pattern can be improved.

As the structural unit (II-1),
As the structural unit represented by the formula (2A), structural units represented by the following formulas (2-2) to (2-10)
As the structural unit represented by the formula (2B), structural units represented by the following formulas (2-1), (2-19) and (2-20)
As the structural unit represented by the formula (2C), structural units represented by the following formulas (2-23) and (2-24) are preferable.

As the structural unit (II-2),
As the structural unit represented by the formula (2D), structural units represented by the following formulas (2-11) to (2-13)
As a structural unit represented by the formula (2E), a structural unit represented by the following formula (2-15)
As the structural unit represented by the formula (2F), structural units represented by the following formulas (2-16) and (2-17) are:
As a structural unit represented by the formula (2G), a structural unit represented by the following formula (2-14)
As a structural unit represented by the formula (2H), a structural unit represented by the following formula (2-18)
As the structural unit represented by the formula (2I), a structural unit represented by the following formula (2-25) is preferable.

In said formula, R < ⁵ > is synonymous with the said Formula (2).

  Among these, from the viewpoint of suppressing the occurrence of bridge defects, the above formulas (2-1) to (2-10), (2-19) to (2-20), and (2-23) to (2-24) The structural units represented by formula (2-1) are more preferred, and among them, the above formulas (2-1) to (2-8), (2- The structural units represented by 19), (2-20) and (2-23) are more preferred.

  [A] In the polymer component, the content of the structural unit (II) is preferably 10% by mole or more and 80% by mole or less, and more preferably 15% by mole or more with respect to all structural units constituting the [A] polymer component. 80 mol% or less is more preferable, and 20 mol% or more and 70 mol% or less is more preferable. By making the content rate of structural unit (II) into the said range, the lithography performance of the resist pattern obtained improves more. In addition, the [A] polymer component may have 1 type, or 2 or more types of structural units (II).

Examples of the monomer that gives the structural unit (II) 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 (III)]
[A] The polymer component preferably has a structural unit (III). The structural unit (III) is a structural unit other than the structural unit (I) and the structural unit (II) and includes a polar group. Since the [A] polymer component further has the structural unit (III), the compatibility between the [A] polymer component and other components such as the [B] acid generator is improved, so that the lithography performance of the resist pattern Can be made more excellent.

  Examples of the polar group include a hydroxyl group, a ketonic carbonyl group, a carboxy group, an amide group, a urethane group, a urea group, a carbonate group, a sulfide group, a sulfonyl group, a halogenated alkyl group, a cyano group, and a thiol group. Among these, a hydroxyl group, a sulfonyl group, and a halogenated alkyl group are preferable, and a hydroxyl group is more preferable.

  As structural unit (III), the structural unit represented by a following formula is mentioned, for example.

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

  [A] The content of the structural unit (III) in the polymer component is preferably 0 mol% or more and 50 mol% or less, and preferably 5 mol% or more and 40 mol%, based on all the structural units constituting the [A] polymer component. The mol% or less is more preferable. [A] The polymer component may have one or more structural units (III).

[Structural unit (IV)]
The structural unit (IV) is a structural unit other than the structural unit (I) and includes the group (a). The said photoresist composition can improve the lithography performance which used MEEF, DOF, and LWR as a parameter | index by containing the [A] polymer component which has structural unit (IV).

  The structural unit (IV) is preferably a structural unit represented by the following formula (3). The said photoresist composition can improve the lithography performance which made MEEF, DOF, and LWR a parameter | index more by containing the [A] polymer component which has a structural unit of the said specific structure.

In the above formula (3), R ¹⁰ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹¹ is a hydrocarbon group having 1 to 10 carbon atoms. X is —O—, —COO—, —OCO— or —NH—. n is an integer of 0-10. When n is 2 or more, the plurality of R ¹¹ and X may be the same or different. R ¹² is a single bond or a hydrocarbon group having 1 to 5 carbon atoms. R ¹³ is the group (a). However, one part or all part of the hydrogen atom which R < ¹¹ > -R < ¹³ > has may be substituted.

Examples of the hydrocarbon group having 1 to 10 carbon atoms represented by R ¹¹ include a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, and 6 to 6 carbon atoms. 10 aromatic hydrocarbon groups and the like.

  Examples of the chain hydrocarbon group having 1 to 10 carbon atoms include a methylene group, an ethylene group, and a propylene group. Of these, a methylene group and an ethylene group are preferred.

  Examples of the alicyclic hydrocarbon group having 3 to 10 carbon atoms include a cyclopropylene group, a cyclohexylene group, and an adamantylene group. Of these, an adamantylene group is preferred.

  As said C6-C10 aromatic hydrocarbon group, a phenylene group, a naphthylene group, etc. are mentioned, for example.

  As said X, -O- and -COO- are preferable.

  As said n, the integer of 0-5 is preferable and 0 and 1 are more preferable.

Examples of the hydrocarbon group having 1 to 5 carbon atoms represented by R ¹² include a chain hydrocarbon group having 1 to 5 carbon atoms and an alicyclic hydrocarbon group having 3 to 5 carbon atoms.

  Examples of the chain hydrocarbon group having 1 to 5 carbon atoms include a methylene group, an ethylene group, and a propylene group. Of these, a methylene group is preferred.

  Examples of the alicyclic hydrocarbon group having 3 to 5 carbon atoms include a cyclopropylene group and a cyclobutylene group.

R ¹² is preferably a single bond or a methylene group.

Examples of the group (a) represented by R ¹³ include:
As the cyclic carbonate group, ethylene carbonate group, 1,3-propylene carbonate group, cyclopentene carbonate group, cyclohexene carbonate group, norbornene carbonate group, etc.
As sultone groups, propiosluton groups, butyrosulton groups, valerosultone groups, adamantane sultone groups, etc.
Examples of the lactone group include a propiolactone group, a butyrolactone group, a valerolactone group, an adamantane lactone group, and the like.

  Of these, the cyclic carbonate group is preferably an ethylene carbonate group, the sultone group is preferably a norbornane sultone group, and the lactone group is preferably a norbornane lactone group or a butyrolactone group.

Examples of the substituent in which part or all of the hydrogen atoms of R ^{11 to} R ¹³ may be substituted include, for example, a halogen atom, a hydroxyl group, a carboxy group, a keto group, a sulfonamide group, an amino group, an amide group, A cyano group, an acetyl group, etc. are mentioned.

  As the structural unit (IV), structural units represented by the following formulas (3-1) to (3-18) can be mentioned as preferred structural units.

In the above formulas (3-1) to (3-18), R ¹⁰ has the same meaning as the above formula (3).

  Among these, from the viewpoint of improving the lithography performance of the photoresist composition, the structural units represented by the above formulas (3-1) to (3-14) are more preferable, and the above formulas (3-1), ( The structural units represented by (3-3) and (3-5) are more preferable.

  [A] In the polymer component, the content of the structural unit (IV) is preferably 5 mol% or more and 80 mol% or less, and preferably 5 mol% or more and 60 mol% or less with respect to all the structural units constituting the [A] polymer component. The mol% or less is more preferable. By making the content rate of structural unit (IV) into the said range, the outstanding lithography performance can be exhibited, maintaining basic characteristics, such as a sensitivity.

  As a monomer compound which gives structural unit (IV), the compound represented by a following formula can be mentioned as a preferable compound.

  [A] The polymer component may further contain a structural unit (V) derived from a non-acid dissociable compound as another structural unit. Here, the non-acid dissociable compound refers to a compound that does not contain a group (acid dissociable group) that dissociates by the action of an acid. [A] When the polymer component contains the structural unit (V), it is possible to form a resist pattern having better lithography properties.

  Examples of the non-acid dissociable compound for generating the structural unit (V) include styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, isobornyl acrylate, tricyclodeca Nyl (meth) acrylate, tetracyclododecenyl (meth) acrylate, etc. are mentioned. Of these, styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, and tricyclodecanyl acrylate are preferable.

  [A] The content of the structural unit (V) in the polymer component is preferably 60 mol% or less, more preferably 50 mol% or less, based on all structural units constituting the [A] polymer component. It is. When this content rate exceeds 60 mol%, there exists a possibility that a lithography characteristic may deteriorate. In addition, 1 type of structural units (V) may be contained in the [A] polymer component, and may be contained 2 or more types.

  In addition, from the viewpoint of improving the lithography performance using MEEF or the like of the photoresist composition as an index, the content of the structural unit (I) in the polymer component [A] is 1 mol% or more and 70 mol% or less, and The total content of the structural unit (I) and the structural unit (II) is preferably 10 mol% or more and 80 mol% or less, and the content of the structural unit (I) is 5 mol% or more and 60 mol% or less. More preferably, the total content of the structural unit (I) and the structural unit (II) is 20 mol% or more and 70 mol% or less. The content of the structural unit (I) is from 10 mol% to 50 mol%, and the total content of the structural unit (I) and the structural unit (II) is from 30 mol% to 60 mol%. Further preferred.

  [A] When the polymer component contains the structural unit (I) and the structural unit (IV) in different polymers, the weight average molecular weight of the polymer (i) having the structural unit (I) It is preferably larger than the weight average molecular weight of the polymer (ii) having the unit (IV). In the photoresist composition, when the polymer component [A] is a blend of the polymer (i) having the structural unit (I) and the polymer (ii) having the structural unit (IV), When the weight average molecular weight of the polymer (i) is larger than the weight average molecular weight of the polymer (ii), the lithography performance using MEEF, LWR or the like as an index is excellent.

<[A] Polymer component synthesis method>
[A] The polymer component can be produced, for example, by polymerizing monomers corresponding to predetermined structural units in a suitable solvent using a radical polymerization initiator. For example, a method of dropping a solution containing a monomer and a radical initiator into a reaction solvent or a solution containing the monomer to cause a polymerization reaction, a solution containing the monomer, and a solution containing the radical initiator Separately, a method of dropping a reaction solvent or a monomer-containing solution into a polymerization reaction, a plurality of types of solutions containing each monomer, and a solution containing a radical initiator, It is preferable to synthesize by a method such as a method of dropping it into a reaction solvent or a solution containing a monomer to cause a polymerization reaction.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30 degreeC-180 degreeC, 40 degreeC-160 degreeC is preferable, and 50 degreeC-140 degreeC is more preferable. The dropping time varies depending on the reaction temperature, the type of initiator, the monomer to be reacted, etc., but is usually 30 minutes to 8 hours, preferably 45 minutes to 6 hours, and more preferably 1 hour to 5 hours. . Further, the total reaction time including the dropping time varies depending on the conditions similarly to the dropping time, but is usually 30 minutes to 8 hours, preferably 45 minutes to 7 hours, and more preferably 1 hour to 6 hours.

  Examples of the radical initiator used for the polymerization include azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis (2-cyclopropyl). Propionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylpropionitrile), and the like. Two or more of these initiators may be mixed and used.

  The polymerization solvent is not limited as long as it is a solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, etc.) and can dissolve the monomer. Examples of the polymerization solvent include alcohol solvents, ketone solvents, amide solvents, ester / lactone solvents, nitrile solvents, and mixed solvents thereof. These solvents can be used alone or in combination of two or more.

  The resin obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after completion of the polymerization reaction, the target resin is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the resin can be recovered by removing low-molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

  [A] When the polymer component is a polymer component having the structural unit (I), the structural unit (II), etc. in the same polymer, the monomer or structural unit giving the structural unit (I) A monomer or the like that gives (II) can be produced by copolymerization by the method described above. [A] When the polymer component is a polymer component having a structural unit such as the structural unit (I) or the structural unit (II) in a different polymer, the monomer that gives each structural unit is the above-described monomer. By polymerizing by the method and mixing them, the [A] polymer component can be prepared.

  [A] The polystyrene-reduced weight average molecular weight (Mw) of the polymer component by gel permeation chromatography (GPC) is not particularly limited, but is preferably 1,000 or more and 500,000 or less, and preferably 2,000 or more and 400,000 or less. More preferred. 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 polystyrene-converted number average molecular weight (Mn) by GPC of the polymer component 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.

  [A] When the polymer component is a polymer component having the structural unit (I) and the structural unit (II) in different polymers, the Mw and Mw / Mn in the respective polymers are as described above. It is good if it is in the same range.

  Here, Mw and Mn are GPC columns (manufactured by Tosoh, 2 G2000HXL, 1 G3000HXL, 1 G4000HXL), flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. The value measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard.

<[B] Acid generator>
[B] The acid generator is a compound that generates an acid by light passing through a mask in an exposure process, which is one process of forming a resist pattern. As the form of inclusion of the [B] acid generator in the photoresist composition, even in an embodiment of a compound as described later (hereinafter, this embodiment is also referred to as “[B] acid generator”), as a part of the polymer It may be a built-in embodiment or both of these embodiments.

  [B] Examples of the acid generator include onium salt compounds, N-sulfonyloxyimide compounds, halogen-containing compounds, and diazoketone compounds. Of these [B] acid generators, onium salt compounds are preferred.

  Examples of the onium salt compounds 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, triphenylsulfonium 2-bicyclo [2.2.1] hept. 2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro N-octane sulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept 2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium Perfluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylphosphonium 1,1 , 2,2-Tetrafluoro-6- (1-adamantanecarbonyloxy) -hexane-1-sulfonate, triphenylsulfonium 2-adamantan-1-yl-1,1-difluoroethane Sulfonates, and the like. Of these, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-6- (1-adamantanecarbonyloxy) -hexane-1 Sulfonate and triphenylsulfonium 2-adamantan-1-yl-1,1-difluoroethane sulfonate are preferred.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium. Nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothio Phenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium trifluoro L-methanesulfonate, 1- (6-n-butoxynaphthalene- -Yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalene) -2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxy Phenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) Tetrahydrothiophenium perfluoro-n-octane Sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, and the like. Can be mentioned. Of these tetrahydrothiophenium salts, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2, 2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiofe Nitroperfluoro-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, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl. -1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4- t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-teto Fluoro ethanesulfonate. Of these iodonium salts, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate is preferred.

  Examples of the N-sulfonyloxyimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyl). Oxy) 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 N-sulfonyloxyimide compounds, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide is preferred.

  These [B] acid generators may be used alone or in combination of two or more. [B] The amount used when the acid generator is a [B] acid generator is the [A] polymer from the viewpoint of ensuring the sensitivity and lithography performance of the resist coating film formed from the photoresist composition. 0.01 mass part or more and 25 mass parts or less are preferable with respect to 100 mass parts of components, and 0.1 mass part or more and 20 mass parts or less are more preferable.

<Optional component>
As optional components that may be contained in the photoresist composition, [C] acid diffusion controller, [D] additive, [E] solvent, [F] polymer containing fluorine atom, alicyclic skeleton containing Examples thereof include compounds, surfactants and sensitizers. Hereinafter, each component will be described in detail.

<[C] acid diffusion controller>
The photoresist composition may further contain a [C] acid diffusion controller. This [C] acid diffusion control agent controls the diffusion phenomenon in the resist film of the acid generated from the [B] acid generator by exposure, and suppresses an undesirable chemical reaction in the non-exposed region. By blending such a [C] acid diffusion control agent, the storage stability of the resulting photoresist composition is improved, the resolution as a resist is further improved, and from exposure to heat treatment after exposure. A change in the line width of the resist pattern due to fluctuations in the holding time (PED) can be suppressed, and a composition having excellent process stability can be obtained.

  [C] As the acid diffusion controller, for example, a nitrogen-containing compound having an Nt-alkoxycarbonyl group is preferably used. Specifically, Nt-butoxycarbonyldi-n-octylamine, Nt-amyloxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-amyloxy Carbonyl di-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-amyloxycarbonyldi-n-decylamine, Nt-butoxycarbonyldicyclohexylamine, Nt-amyloxycarbonyldicyclohexylamine Nt-butoxycarbonyl-1-adamantylamine, Nt-amyloxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-amyloxycarbonyl-2-adamantylamine Nt-butoxycarbonyl-N-methyl-1 Adamantylamine, Nt-amyloxycarbonyl-N-methyl-1-adamantylamine, (S)-(-)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (S)-(-)- 1- (t-amyloxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t- Amyloxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine, Nt-butoxycarbonylpyrrolidine, Nt-amyloxycarbonyl Pyrrolidine, N, N′-di-t-butoxycarbonylpiperazine, N, N′-di-t-amyloxycarbonylpipe Gin, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-amyloxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′-diaminodiphenylmethane, Nt-amyloxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N′-di-t-amyloxycarbonylhexamethylenediamine, N, N , N ′, N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N, N ′, N′-tetra-t-amyloxycarbonylhexamethylenediamine, N, N′-di-t-butoxycarbonyl- 1,7-diaminoheptane, N, N′-di-t-amyloxycarbonyl-1,7-diaminoheptane, N, N '-Di-t-butoxycarbonyl-1,8-diaminooctane, N, N'-di-t-amyloxycarbonyl-1,8-diaminooctane, N, N'-di-t-butoxycarbonyl-1, 9-diaminononane, N, N′-di-t-amyloxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t -Amyloxycarbonyl-1,10-diaminodecane, N, N'-di-t-butoxycarbonyl-1,12-diaminododecane, N, N'-di-t-amyloxycarbonyl-1,12-diaminododecane N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-t-amyloxycarbonyl-4,4′-diaminodiphenylmethane, N t-butoxycarbonylbenzimidazole, Nt-butoxycarbonylbenzimidazole, Nt-amyloxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, Nt-amyloxycarbonyl And compounds such as -2-phenylbenzimidazole. Of these, Nt-butoxycarbonyl-4-hydroxypiperidine and Nt-amyloxycarbonyl-4-hydroxypiperidine are preferred.

  [C] In addition to the above compounds, for example, nitrogen-containing compounds such as tertiary amine compounds, quaternary ammonium hydroxide compounds, and nitrogen-containing heterocyclic compounds are used as the acid diffusion controller.

Examples of tertiary amine compounds include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octyl. Tri (cyclo) alkylamines such as amine, cyclohexyldimethylamine, dicyclohexylmethylamine, and tricyclohexylamine;
Fragrances such as aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline Group amines;
Alkanolamines such as triethanolamine and N, N-di (hydroxyethyl) aniline;
N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1- Methylethyl] benzenetetramethylenediamine, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether and the like.

  Examples of the quaternary ammonium hydroxide compound include tetra-n-propylammonium hydroxide and tetra-n-butylammonium hydroxide.

  Examples of the nitrogen-containing heterocyclic compound include 2-phenylbenzimidazole, pyridine, 2-methylpyridine, pyrazine, pyrazole and the like. Of these, 2-phenylbenzimidazole is preferred.

  Furthermore, as the [C] acid diffusion control agent, an onium salt compound that decomposes by exposure and loses basicity as acid diffusion controllability can be used. Specific examples of such an onium salt compound include a sulfonium salt compound represented by the following formula (4-1) and an iodonium salt compound represented by the following formula (4-2).

R ^{c1 to} R ^c5 in the above formulas (4-1) and (4-2) are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom.
Anb ⁻ represents OH ⁻ , R ^c6 —COO ⁻ , R ^c6 —SO ₃ ^— (wherein R ^c6 independently represents an alkyl group, an aryl group, or an alkanol group), or the following formula: The anion represented by (5) is represented.

  Specific examples of the sulfonium salt compound and the iodonium salt compound include triphenylsulfonium hydroxide, triphenylsulfonium acetate, triphenylsulfonium salicylate, diphenyl-4-hydroxyphenylsulfonium hydroxide, diphenyl-4-hydroxyphenylsulfonium acetate. Diphenyl-4-hydroxyphenylsulfonium salicylate, bis (4-t-butylphenyl) iodonium hydroxide, bis (4-t-butylphenyl) iodonium acetate, bis (4-t-butylphenyl) iodonium hydroxide, Bis (4-t-butylphenyl) iodonium acetate, bis (4-t-butylphenyl) iodonium salicylate, 4-t- Tylphenyl-4-hydroxyphenyliodonium hydroxide, 4-t-butylphenyl-4-hydroxyphenyliodonium acetate, 4-t-butylphenyl-4-hydroxyphenyliodonium salicylate, bis (4-t-butylphenyl) iodonium Examples thereof include 10-camphor sulfonate, diphenyliodonium 10-camphor sulfonate, triphenylsulfonium 10-camphor sulfonate, and 4-t-butoxyphenyl diphenylsulfonium 10-camphor sulfonate. Of these, triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate are preferred.

  [C] The acid diffusion controller can be used alone or in combination of two or more. The content ratio of the acid diffusion controller is preferably 10 parts by mass or less, and more preferably 0.1 parts by mass or more and 8 parts by mass or less with respect to 100 parts by mass of the polymer component [A]. When the amount used exceeds 10 parts by mass, the sensitivity as a resist tends to decrease.

<[D] Additive>
The photoresist composition can be blended with an additive [D] when a resist pattern is formed using an immersion exposure method. Examples of the [D] additive that may be contained in the photoresist composition include γ-butyrolactone, propylene carbonate, and the like. Of these, γ-butyrolactone is preferred.

<[E] solvent>
The photoresist composition usually contains an [E] solvent. The solvent contained in the photoresist composition is not particularly limited as long as it is a solvent capable of dissolving at least the [A] polymer component, the [B] acid generator, and other components. As the solvent, alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents and the like can be used.

As an alcohol solvent, for example,
Methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, tert-butanol, n-pentanol, i-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, furfuryl 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 ether solvent include diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether and the like.

  Examples of ketone solvents include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n. -Hexylketone, di-i-butylketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, acetophenone, and the like.

  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 ester solvents include diethyl carbonate, methyl acetate, ethyl acetate, γ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, and n-acetate. Pentyl, 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, ethyl acetoacetate, Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene acetate Cole 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, methoxytriglycol acetate, propionic acid Ethyl, n-butyl propionate, i-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, And diethyl phthalate.

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

  These organic solvents may be used alone or in combination of two or more.

<[F] Polymer containing fluorine atom>
The photoresist composition may further contain a polymer containing [F] fluorine atoms (hereinafter also referred to as “[F] polymer”). [F] A polymer is a polymer containing a fluorine atom, and it is preferable that a fluorine atom content rate is higher than a [A] polymer component. When the photoresist composition contains the [F] polymer, the hydrophobicity of the resist film is improved, and even when immersion exposure is performed, it is excellent in suppressing substance elution, and between the resist film and the immersion liquid. The receding contact angle can be made sufficiently high, and there are effects such as no water droplets remaining when scanning exposure is performed at high speed, so that the usefulness of the photoresist composition for immersion exposure is enhanced.

[F] As an aspect of the polymer, for example,
A structure in which a fluorinated alkyl group is bonded to the main chain;
Structure in which a fluorinated alkyl group is bonded to the side chain;
Examples include a structure in which a fluorinated alkyl group is bonded to the main chain and the side chain.

  Examples of the monomer that gives a structure in which a fluorinated alkyl group is bonded to the main chain include, for example, α-trifluoromethyl acrylate compound, β-trifluoromethyl acrylate compound, α, β-trifluoromethyl acrylate compound, one or more types And the like in which the hydrogen at the vinyl moiety is substituted with a fluorinated alkyl group such as a trifluoromethyl group.

  Examples of monomers that give a structure in which a fluorinated alkyl group is bonded to the side chain include, for example, those in which the side chain of an alicyclic olefin compound such as norbornene is a fluorinated alkyl group or a derivative thereof, acrylic acid or methacrylic acid. Examples include ester compounds in which the side chain is a fluorinated alkyl group or a derivative thereof, and one or more olefin side chains (sites not including a double bond) being a fluorinated alkyl group or a derivative thereof.

  Monomers that give a structure in which a fluorinated alkyl group is bonded to the main chain and side chain include, for example, α-trifluoromethylacrylic acid, β-trifluoromethylacrylic acid, α, β-trifluoromethylacrylic acid. Such as a fluorinated alkyl group or a derivative thereof, or a compound in which one or more vinyl moiety hydrogens are substituted with a fluorinated alkyl group such as a trifluoromethyl group. Substituted with a derivative, the hydrogen bonded to the double bond of one or more alicyclic olefin compounds is replaced with a fluorinated alkyl group such as a trifluoromethyl group, and the side chain is a fluorinated alkyl group or its Examples thereof include derivatives. In addition, an alicyclic olefin compound shows the compound in which a part of ring is a double bond.

  [F] The polymer preferably has a structural unit (f1) represented by the following formula (6) and / or a structural unit (f2) represented by the formula (7), and the structural unit (f1) and You may have "another structural unit" other than a structural unit (f2). Hereinafter, each structural unit will be described in detail.

[Structural unit (f1)]
The structural unit (f1) is a structural unit represented by the following formula (6).

In the above formula (6), R ¹⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁸ is a linear or branched alkyl group having 1 to 6 carbon atoms having a fluorine atom, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms having a fluorine atom. However, in the alkyl group and alicyclic hydrocarbon group, part or all of the hydrogen atoms may be substituted.

  Examples of the monomer that gives the structural unit (f1) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, perfluoro n-propyl ( (Meth) acrylate, perfluoro i-propyl (meth) acrylate, perfluoro n-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, perfluoro t-butyl (meth) acrylate, perfluorocyclohexyl (meth) Acrylate, 2- (1,1,1,3,3,3-hexafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoro) pentyl ( (Meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoro) hex (Meth) acrylate, perfluorocyclohexylmethyl (meth) acrylate, 1- (2,2,3,3,3-pentafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4, 4,4-Heptafluoro) penta (meth) acrylate, 1- (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- Heptadecafluoro) decyl (meth) acrylate, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6-octafluoro) hexyl (meth) acrylate and the like.

  Examples of the structural unit (f1) include structural units represented by the following formulas (6-1) and (6-2).

In the formulas (6-1) and (6-2), R ¹⁷ has the same meaning as the formula (6).

  In the [F] polymer, the content of the structural unit (f1) is preferably 10 mol% or more and 70 mol% or less, and more preferably 20 mol% or more and 50 mol% with respect to all the structural units constituting the [F] polymer. The following is more preferable. [F] The polymer may have one or more structural units (f1).

[Structural unit (f2)]
The structural unit (f2) is a structural unit represented by the following formula (7).

In the above formula (7), R ¹⁹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ²⁰ is a (k + 1) -valent linking group. Y is a divalent linking group having a fluorine atom. R ²¹ is a hydrogen atom or a monovalent organic group. k is an integer of 1 to 3. However, when k is 2 or 3, the plurality of Y and R ²¹ may be the same or different.

  Examples of the structural unit (f2) include structural units represented by the following formulas (7-1) and (7-2).

In the formula (7-1), R ²⁰ is a divalent linear, branched or cyclic hydrocarbon group of saturated or unsaturated having 1 to 20 carbon atoms. R ¹⁹ , Y and R ²¹ have the same meaning as in the above formula (7).
In said formula (7-2), R < ¹⁹ >, Y, R < ²¹ > and k are synonymous with said formula (7). However, when k is 2 or 3, the plurality of Y and R ²¹ may be the same or different.

  Examples of the structural unit represented by the above formula (7-1) and formula (7-2) include the following formula (7-1-1), formula (7-1-2), and formula (7-2-1). ).

In the formulas (7-1-1), (7-1-2), and (7-2-1), R ¹⁹ has the same meaning as the formula (7).

  Examples of the monomer that gives the structural unit (f2) include (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester and (meth) acrylic acid. (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy -5-pentyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, (meth) acrylic acid 2-{[5- ( 1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl} ester and the like.

  In the [F] polymer, the content of the structural unit (f2) is preferably 20% by mole or more and 80% by mole or less, and more preferably 30% by mole or more and 70% by mole with respect to all the structural units constituting the [F] polymer. The following is more preferable. In addition, the [F] polymer may have 1 type, or 2 or more types of structural units (f2).

  [F] The polymer further includes, as “other structural units”, a structural unit having a lactone structure, a cyclic carbonate structure or a sultone structure for enhancing solubility in a developer, and an alicyclic structure for enhancing etching resistance. One or more structural units may be included.

  Examples of the structural unit having a lactone structure, a cyclic carbonate structure or a sultone structure include the same structural units as those exemplified as the structural unit (IV) of the above-mentioned [A] polymer component.

  As a structural unit containing an alicyclic structure, the structural unit represented, for example by following formula (8) is mentioned.

In the formula (8), R ²² is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y ² is an alicyclic hydrocarbon group having 4 to 20 carbon atoms.

As a monomer which gives the structural unit containing an alicyclic compound, for example, (meth) acrylic acid-bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-bicyclo [2.2. 2] Oct-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 ] dec-1-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] dec-2-yl ester, and the like.

  In the [F] polymer, the structural unit (f1), the structural unit (f2), and the other structural unit may have only one kind of each structural unit or may contain two or more kinds. [F] The polymer preferably contains no unit having an aromatic group. In particular, when an ArF light source is used, it may cause a decrease in sensitivity. Further, when developing with a negative developer, the shape may deteriorate.

  [F] As a content rate of a polymer, 1 mass part-15 mass parts are preferable with respect to 100 mass parts of [A] polymer components, and 2 mass parts-10 mass parts are more preferable.

<[F] Polymer Synthesis Method>
[F] The polymer can be produced, for example, by polymerizing a monomer corresponding to each predetermined structural unit in a suitable solvent using a radical polymerization initiator. In addition, as a polymerization initiator, a solvent, etc. which are used for the synthesis | combination of a [F] polymer, the thing similar to what was illustrated in the synthesis method of the said [A] polymer component can be mentioned.

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

  [F] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is preferably 1,000 to 50,000, more preferably 1,000 to 30,000, and 1,000. Is particularly preferred. [F] When the Mw of the 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.

  [F] The ratio (Mw / Mn) of Mw of the polymer to the number average molecular weight (Mn) in terms of polystyrene by GPC method is usually 1 to 3, preferably 1 to 2.

[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 the [A] polymer component, the [B] acid generator and the optional component in a predetermined ratio in the solvent. When the photoresist composition is used, it is usually dissolved in a solvent so that the total solid concentration is 1% by mass to 30% by mass, preferably 1.5% by mass to 25% by mass. It is prepared by filtering with a filter of about 2 μm.

<Method for forming resist pattern>
A method for forming a resist pattern using the photoresist composition of the present invention will be described below.

As a method of forming a resist pattern using the photoresist composition,
(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”). (Also referred to as (3))
And the like. Hereinafter, each process is explained in full detail.

  According to the said formation method, the resist pattern excellent in MEEF, LWR, and DOF can be formed using the said photoresist composition. Therefore, even with radiation such as KrF excimer laser light, ArF excimer laser light, EUV, etc., a fine pattern can be formed from the photoresist composition with high accuracy and stability, and further miniaturization will progress in the future. It can be suitably used for expected semiconductor device manufacturing.

[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 by a coating means such as spin coating, cast coating, roll coating or the like. It is applied to a substrate such as a wafer coated with a prevention film so as to have a predetermined film thickness, and in some cases, the solvent in the coating film is usually baked (SB) at a temperature of about 70 ° C. to 160 ° C. Volatilizes 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 light (wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm) are preferable, and finer patterns such as EUV (extreme ultraviolet light, wavelength 13.5 nm) can be formed. Even a light source can be suitably used. Subsequently, it is preferable to perform post-exposure baking (PEB). By this PEB, it is possible to smoothly proceed with elimination of the acid dissociable group of the [A] polymer component. The heating condition of PEB can be appropriately selected depending on the composition of the photoresist composition, but is usually about 50 ° C to 180 ° C.

[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 WO2005-069096, WO2006-035790, 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 using GPC columns (manufactured by Tosoh Corporation, two G2000HXL, one G3000HXL, one G4000HXL) under the following conditions.
Column temperature: 40 ° C
Elution solvent: dimethylformamide (LiBr 0.3 mass%, H ₃ PO ₄ 0.1 mass% 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

The structural unit derived from the monomer in the polymer was analyzed using a nuclear magnetic resonance apparatus (JNM-ECX400, manufactured by JEOL Ltd.) and using deuterated chloroform as a measurement solvent. The content rate of the structural unit in a polymer can be calculated | required as an average value in a polymer from the area ratio of the peak corresponding to each structural unit in the obtained spectrum by measuring the ¹³ C-NMR spectrum of a polymer.

<[A] Synthesis of polymer component>
[A] The monomer used for the synthesis | combination of a polymer component and the [F] polymer mentioned later is shown below.

  Among the monomer compounds that give the structural unit (I), the compound represented by the above formula (Ss-1) and the compound represented by the formula (Ss-2) were synthesized by the following method.

[Synthesis Example 1]
To a 1 L three-necked reactor equipped with a dropping funnel and a condenser, 13.1 g (200 mmol) of zinc powder (Wako Pure Chemical Co., Ltd., Wako Special Grade) was added and brought to an argon atmosphere. Then, 240 mL of tetrahydrofuran (THF) was added and magnetized. While stirring with a tic stirrer, 1.9 mL (15 mmol) of chlorotrimethylsilane was added, and the mixture was stirred at 20 ° C. to 25 ° C. for 30 minutes. A solution prepared by dissolving 20.0 g (200 mmol) of 2-methyltetrahydrofuran-3-one in 40 mL of THF was added thereto. Next, a solution of 34.8 g (180 mmol) of ethyl (2-bromomethyl) acrylate in 50 mL of THF was added dropwise. After dropping, the mixture was stirred at room temperature for 2 hours. After confirming the completion of the reaction by gas chromatography, an aqueous ammonium chloride solution and ethyl acetate were added to separate the layers. The obtained organic layer was washed successively with water and saturated brine. Thereafter, the organic layer was dried over magnesium sulfate and concentrated under reduced pressure. Thereafter, distillation under reduced pressure was performed, and 20.4 g of 6-methyl-3-methylene-1,7-dioxaspiro [4.4] nonan-2-one (compound represented by the above formula (Ss-1)) as a transparent oily substance. Got.

[Synthesis Example 2]
To a 1000 mL three-necked reactor, 22.4 g (200 mmol) of 1,4-cyclohexanedione was added, and 300 mL of methanol was added thereto, and dissolved by stirring with a magnetic stirrer. After the reactor was lowered to 0 ° C., a methanol solution in which 2.65 g of sodium hydroborate was dissolved was added to cause the reaction. Thereafter, the mixture was poured into a saturated aqueous ammonium chloride solution and extracted with ethyl acetate. The extract was dried under reduced pressure to obtain 12 g of a crude product. Next, this crude product was put into a 300 mL three-necked reactor, 100 mL of methylene chloride was added, and the mixture was stirred and dissolved with a magnetic stirrer. Thereto, 15.5 g (227 mmol) of imidazole and 4.2 g (34 mmol) of dimethylaminopyridine were added, and then the reactor was cooled to 0 ° C. Next, 25.7 g (170 mmol) of tert-butyldimethylsilyl chloride was added and reacted at 0 ° C. for 2 hours and then at room temperature for 6 hours. Next, an aqueous ammonium chloride solution was added for liquid separation. The obtained organic layer was washed successively with water and saturated brine, and then the organic layer was dried over magnesium sulfate and concentrated under reduced pressure. Thereafter, purification was performed with a short column to obtain 9.5 g of a crude product. Next, the reaction using zinc powder was carried out in the same manner as in Synthesis Example 1 to obtain 4.3 g of a crude product. Subsequently, after dissolving the crude product in 5 mL of tetrahydrofuran, 50 ml of 1 mol / L tetrabutylammonium fluoride-THF solution was added, extracted with ethyl acetate reacted for 18 hours, washed with water and saturated brine Then, it was purified by column chromatography to obtain 2.5 g (14 mmol) of the compound represented by the above formula (Ss-2).

  [A] The polymer component was synthesized by the following method using the monomer compound represented by the above formula.

[Synthesis Example 3]
20 g (50 mol%) of compound (M-1) and 20 g (50 mol%) of compound (Ss-1) are dissolved in 80 g of 2-butanone, and 3.9 g of AIBN is added to prepare a monomer solution. did. A 200 mL three-necked flask containing 40 g of 2-butanone 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 800 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 160 g of methanol, filtered and dried at 50 ° C. for 17 hours to obtain a white powdery polymer component (A-1) (30 g, yield 75%). ). Mw of the obtained polymer component (A-1) was 4,500, and Mw / Mn was 1.4. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from the compound (M-1) to the structural unit derived from the compound (Ss-1) was 50:50 (mol%).

[Synthesis Examples 4-30, Comparative Synthesis Examples 1-3]
The polymer components (A-2) to (A-28) and (a-1) to (a-3) were operated in the same manner as in Synthesis Example 3 except that a predetermined amount of the monomers listed in Table 1 were blended. ) In addition, Table 1 shows the Mw, Mw / Mn, yield (%), and the content ratio of the structural unit derived from each monomer in each polymer.

[Synthesis Example 31]
20 g (50 mol%) of compound (M-1) and 20 g (50 mol%) of compound (Ss-1) are dissolved in 80 g of 2-butanone, and 1.95 g of azobisisobutyronitrile (AIBN) is added. A monomer solution was prepared. A 200 mL three-necked flask containing 40 g of 2-butanone 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 800 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 160 g of methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (35 g, yield 88%). Furthermore, a polymer was obtained by the same method as above except that 22.8 g (50 mol%) of the compound (L-1) was used instead of 20 g (50 mol%) of the compound (Ss-1). The above two types of polymers were mixed at a molar ratio of 1: 1 to obtain a polymer component (A-29). The physical properties of the two types of polymers are shown in Table 1.

[Synthesis Example 32]
A polymer component (A-30) was obtained in the same manner as in Synthesis Example 31, except that a predetermined amount of the monomers listed in Table 1 were blended. Moreover, Mw of each obtained polymer, Mw / Mn, and the content rate of the structural unit derived from each monomer in each polymer are shown together in Table 1.

<Synthesis of [F] polymer>
[Synthesis Example 33]
13.7 g (50 mol%) of the compound (M-7) and 16.3 g (50 mol%) of the compound (X-5) are dissolved in 60 g of 2-butanone, and 1.82 g of AIBN is added to the monomer solution. Was prepared. A 300 mL three-necked flask containing 30 g of 2-butanone 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 polymerization solution was put into 600 g of methanol: water = 8: 2 solution, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 120 g of methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdery polymer component (F-1) (24 g, yield 80%). ). Mw of the obtained polymer (F-1) was 4,100, and Mw / Mn was 1.4. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from the compound (M-7): the structural unit derived from the compound (X-5) was 48.5: 51.5 (mol%). .

[Synthesis Examples 34 to 35]
Polymers (F-2) to (F-3) were obtained in the same manner as in Synthesis Example 33 except that a predetermined amount of the monomers listed in Table 2 were blended. Table 2 shows the Mw, Mw / Mn of each polymer obtained, and the content of the structural unit derived from each monomer in each polymer.

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

<[B] Acid generator>
B-1 to B-4: Compounds represented by the following formulas

<[C] acid diffusion controller>
C-1 to C-5: a compound represented by the following formula

<[D] Additive>
D-1: γ-butyrolactone

<[E] solvent>
E-1: Propylene glycol monomethyl ether acetate E-2: Cyclohexanone

[Example 1]
100 parts by mass of polymer component (A-1), 10 parts by mass of acid generator (B-1), 5 parts by mass of acid diffusion controller (C-3), 3 parts by mass of polymer (F-1), additive (D-1) 30 parts by mass, solvent (E-1) 2,600 parts and (E-2) 1,100 parts by mass were mixed, and the resulting mixed solution was filtered through a filter having a pore size of 0.2 μm. Thus, a photoresist composition was prepared.

[Examples 2 to 30 and Comparative Examples 1 to 3]
A photoresist composition was prepared in the same manner as in Example 1 except that each type and amount of components shown in Table 3 were used.

<Evaluation>
The following evaluation was performed about the photoresist composition of Examples 1-30 and Comparative Examples 1-3. The evaluation results are shown in Table 4. A scanning electron microscope (CG4000, manufactured by Hitachi High-Technologies Corporation) was used for measuring the resist pattern and measuring the bridge defect.
[sensitivity]
A 12-inch silicon wafer on which a lower antireflection film (“ARC66”, manufactured by Nissan Chemical Industries) was formed was soft-baked (SB) at 120 ° C. for 60 seconds with a photoresist composition to form a film having a thickness of 75 nm. Next, using this ArF excimer laser immersion exposure apparatus (NSR S610C, manufactured by NIKON), a mask pattern for pattern formation of 50 nm Line 100 nm Pitch is formed on this film under the conditions of NA = 1.3, ratio = 0.800, and Annular. Exposed through. After the exposure, post-baking (PEB) was performed for 60 seconds at the temperature shown in Table 4. 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, an exposure amount at which a portion exposed through a mask pattern for forming a pattern of 50 nm Line 100 nm Pitch forms a Line having a line width of 50 nm was defined as an optimum exposure amount (Eop). This optimum exposure dose was taken as the sensitivity (mJ / cm ² ), and when this sensitivity was 40 (mJ / cm ² ) or less, it was evaluated as good.

[MEEF]
In the above Eop, LS patterns were formed through mask patterns for forming patterns of 48 nm Line 100 nm Pitch, 49 nm Line 100 nm Pitch, 50 nm Line 100 nm Pitch, 51 nm Line 100 nm Pitch, and 52 nm Line 100 nm Pitch, respectively. At this time, the slope of the straight line when the line size (nm) of the mask 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. As the MEEF (straight line) is closer to 1, the mask reproducibility is better.

[LWR]
The line width 50 nm Line 100 nm Pitch formed by the Eop was observed from the upper part of the pattern using the scanning electron microscope, 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 5.4 nm or less, it was evaluated that the formed pattern shape was good.

[DOF]
When the pattern dimension resolved by the 50 nm Line 100 nm Pitch pattern mask at Eop is within ± 10% of the mask design dimension, DOF (nm) was used as the focus fluctuation width.

[Bridge defect suppression]
The defect distribution was confirmed using a defect inspection apparatus (KLA2810, manufactured by KLA-Tencor) for the pattern having a line width of 50 nm Line 100 nm Pitch formed by the above Eop. Subsequently, the number of bridge defects per wafer was measured using the scanning electron microscope, and the measured value was regarded as bridge defect suppression. If the measured value is less than 20, the bridging defect suppression is good, 20 to 50 is slightly good, and if it exceeds 50, it can be evaluated as defective.

[Pattern fall resistance]
When the amount of exposure is increased through a mask pattern for pattern formation of 50 nm Line 100 nm Pitch, the minimum line pattern dimension at which pattern collapse does not occur is measured using the scanning electron microscope, and this measured value is measured against pattern collapse resistance ( nm). At this time, if the measured value is 35 nm or less, the pattern collapse resistance is good, and if it exceeds 35 nm, it can be evaluated as defective.

  As shown in Table 4, it was found that the photoresist composition of the present invention was excellent in all lithography performances using sensitivity, MEEF, DOF, LWR and the like as indices. In addition, when the photoresist composition has at least one selected from the group consisting of the structural units represented by the above formulas (2A) to (2C) as the structural unit (II), the bridge defect suppression property is In the case where the structural unit (II) further has at least one selected from the group consisting of the structural units represented by the above formulas (2D) to (2I) as the structural unit (II), the bridge defect suppression property and the pattern collapse resistance are Both were good results.

  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] the same or different in the polymer, the structural unit (I), the following equation (2) represented by the acid-dissociable group-containing structural units (II) and lactone group represented by the following formula (1), cyclic A photoresist composition comprising a polymer component having at least one group (a) selected from the group consisting of a carbonate group and a sultone group , and [B] an acid generator.

(In Formula (1), R ⁰ is a hydrogen atom, a fluorine atom, a hydroxyl group, or a monovalent organic group having 1 to 20 carbon atoms. R ¹ and R ² are each independently a hydrogen atom or a fluorine atom. A hydroxyl group or a monovalent organic group having 1 to 20 carbon atoms, or R ¹ and R ² are bonded to each other to form a ring structure having 3 to 10 carbon atoms together with the carbon atom to which they are bonded. A is an integer of 1 to 6. However, when a is 2 or more, a plurality of R ¹ and R ² may be the same or different, and R ³ and R ⁴ are each independently And a hydrogen atom, a fluorine atom, a hydroxyl group, or a monovalent organic group having 1 to 20 carbon atoms, or R ³ and R ⁴ are bonded to each other and have 3 to 10 carbon atoms together with the carbon atom to which they are bonded. Provided that one of the hydrogen atoms contained in the ring structure is Or all may be substituted. In addition, at least one of R ⁰ to R ⁴ is a group containing a hetero atom.
In formula (2), R ⁵ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁶ and R ⁷ are each independently an alkyl group having 1 to 4 carbon atoms or an alicyclic group having 4 to 20 carbon atoms, or R ⁶ and R ⁷ are bonded to each other. A divalent alicyclic group is formed together with the carbon atom. R ⁸ is an alkyl group having 1 to 4 carbon atoms or an alicyclic group having 4 to 20 carbon atoms. Some or all of the hydrogen atoms of the alkyl group and alicyclic group may be substituted. ) [A] The photoresist composition according to claim 1, wherein the polymer component contains at least one selected from the group consisting of structural units represented by the following formulas (2A) to (2C) as the structural unit (II). object.

(In the formulas (2A) to (2C), R ⁵ has the same meaning as the above formula (2). Each R ^A is independently an alkyl group having 1 to 4 carbon atoms. Each is independently an integer of 1 to 6.) [A] The photoresist according to claim 2, wherein the polymer component further contains at least one selected from the group consisting of structural units represented by the following formulas (2D) to (2I) as the structural unit (II). Composition.

(In the formula (2D) ~ (2I), R 5 is as defined in the above formula (2) .R ^A is as defined in the above formula (2A) ~ (2C) .R B are each independently And an alkyl group having 1 to 4 carbon atoms.)   [A] The photoresist composition according to claim 1, wherein the polymer component further comprises a structural unit (III) containing a polar group, which is a structural unit other than the structural unit (I) and the structural unit (II). The photoresist composition according to any one of claims 1 to 4, wherein the group (a) is contained in a structural unit (IV) other than the structural unit (I). The photoresist composition according to claim 1 , wherein the group (a) is contained in the structural unit (I).   The photoresist composition according to claim 1, wherein the acid dissociable group contained in the structural unit (II) has 4 to 9 carbon atoms.   [A] The total content of the structural unit (I) and the structural unit (II) in the polymer component is 20 mol% to 70 mol%, and the content of the structural unit (I) is 5 mol% to 60 mol. The photoresist composition according to claim 1, which is not more than mol%.