JP4817063B2 - Method for producing (meth) acrylic acid-based (co) polymer having perfluoroalkyl group and radiation-sensitive resin composition using (co) polymer obtained by the method - Google Patents

Description

  The present invention relates to a method for producing a (meth) acrylic acid-based (co) polymer having a perfluoroalkyl group at the α-position of a hydroxyl group, and a radiation-sensitive resin composition using the (co) polymer obtained by the method. In particular, it is suitable as a chemically amplified resist useful for microfabrication using various types of radiation such as deep ultraviolet rays such as KrF excimer laser and ArF excimer laser, charged particle beams such as electron beams, and X-rays such as synchrotron radiation. The present invention relates to a method for producing a (meth) acrylic acid-based (co) polymer that can be used in the process.

In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, lithography technology capable of microfabrication at a level of 0.20 μm or less is required.
However, in the conventional lithography process, near ultraviolet rays such as i rays are generally used as radiation, and it is said that fine processing at the sub-quarter micron level is extremely difficult with this near ultraviolet rays.
Therefore, in order to enable fine processing at a level of 0.20 μm or less, use of radiation having a shorter wavelength is being studied. Examples of such short-wavelength radiation include an emission line spectrum of a mercury lamp, far-ultraviolet rays typified by an excimer laser, an X-ray, an electron beam, and the like. ) Or ArF excimer laser (wavelength 193 nm) has been attracting attention.

As a radiation-sensitive resin composition suitable for irradiation with such an excimer laser, a component having an acid-dissociable functional group and a component that generates an acid upon irradiation with radiation (hereinafter referred to as “exposure”) (hereinafter referred to as “ Many compositions utilizing the chemical amplification effect of the acid generator (hereinafter referred to as “chemically amplified radiation-sensitive composition”) have been proposed, but this composition was generated by exposure. The acid-dissociable functional group present in the polymer is dissociated by the action of the acid, and the polymer has an acidic group. As a result, the exposed region of the resist film becomes readily soluble in an alkali developer. This is a phenomenon.
In the chemically amplified radiation-sensitive composition applicable to short-wavelength radiation typified by such far-ultraviolet rays, from the viewpoint of technological development that can cope with the progress of miniaturization in semiconductor elements, the transparency to radiation is high, Moreover, development of new resin components that are excellent in basic physical properties as resists such as sensitivity, resolution, dry etching resistance, and pattern shape, have few development defects, and are excellent in storage stability is underway.

For example, as a method for increasing the radiation transmittance of a resist film, instead of a phenolic resin, which is a resin component that has been used in conventional representative chemically amplified radiation-sensitive compositions, transparency to deep ultraviolet rays is high ( A (meth) acrylic resin is used.
In addition, as one of the measures for improving dry etching resistance without impairing transparency to far ultraviolet rays, a chemically amplified radiation-sensitive composition using a (meth) acrylic acid-based resin having an aliphatic ring has been proposed. Yes.
However, those obtained by introducing an aliphatic ring into the resin component of the chemically amplified radiation-sensitive composition have a very high hydrophobicity of the resin itself and have a problem in adhesion to the substrate.
As a resin component that solves this problem, a (meth) acrylic acid copolymer having a fluoroalkyl group at the α-position of a hydroxyl group is used (for example, Patent Document 1).

On the other hand, in a chemically amplified radiation sensitive composition using a (meth) acrylic acid copolymer as a resin component, resolution is improved by using a (meth) acrylic acid copolymer having a narrow molecular weight distribution. It is known that a chemically amplified radiation-sensitive composition having excellent properties such as improvement of the surface roughness, reduction of line edge roughness, and improvement of the rectangularity of the cross-sectional resist pattern can be obtained. Alternatively, a polymerization method using an anionic polymerization initiator in the presence of an additive composed of an alkaline earth metal salt is used. (For example, Patent Documents 2 and 3)
However, in order to obtain a (meth) acrylic acid copolymer having a fluoroalkyl group at the α-position of the above-mentioned hydroxyl group, if an attempt is made to produce it using the above anionic polymerization method, the monomer used for the production will have a hydroxyl group. Therefore, there is a problem that it is difficult to perform anionic polymerization.
JP 2005-43852 A JP 2003-82010 A JP 2003-84436 A

  An object of the present invention is to provide a (meth) acrylic acid type (co) by a living anion polymerization method using at least one monomer including a (meth) acrylate having a perfluoroalkyl group at the α-position of a hydroxyl group and a derivative thereof. It is in providing the method of manufacturing a polymer.

  As a result of intensive studies to achieve the above object, the present inventors can perform living anion polymerization by using a monomer in which a hydroxyl group having a perfluoroalkyl group at the α-position is protected with an acid-dissociable protecting group. I got the knowledge that

The present invention has been completed based on this finding, and is as follows.
(1) A method for producing a (meth) acrylic acid copolymer used in a chemically amplified radiation-sensitive resin composition, comprising (meth) acrylate having a perfluoroalkyl group at the α-position of a hydroxyl group and a derivative thereof A (meth) acrylic acid type wherein at least one monomer is used and the hydroxyl group of the monomer is protected with an alkyl vinyl ether, and then living anion polymerization is performed in the presence of alkyl lithium and a mineral acid salt. A method for synthesizing a copolymer.
(2) living room after the anionic polymerization method of (meth) acrylic acid copolymer of the above (1), characterized in that to dissociate a protecting group of the above.

According to the production method of the present invention, the living anion polymerization can be performed even if the (meth) acrylate or derivative thereof used as a monomer contains a hydroxyl group having a perfluoroalkyl group at the α-position. The resulting (meth) acrylic acid-based (co) polymer has a narrow molecular weight distribution. When it is used as a resin component, the resolution is improved, the line edge roughness is reduced, and the cross-sectional resist pattern is rectangular. A chemically amplified radiation-sensitive composition having excellent characteristics such as improvement is obtained. Moreover, the radiation sensitive resin composition which uses the (meth) acrylic acid type | system | group (co) polymer obtained by the manufacturing method of this invention as a resin component is actinic light, for example, KrF excimer laser (wavelength 248nm), ArF excimer laser It has high transparency to far ultraviolet rays represented by (wavelength 193 nm) and is useful as a chemically amplified resist sensitive to these far ultraviolet rays.

Hereinafter, the present invention will be described in more detail.
The (meth) acrylate having a perfluoroalkyl group at the α-position of the hydroxyl group in the present invention is represented by the following general formula.

Furthermore, when the (meth) acrylic acid ester-based (co) polymer obtained by polymerizing the (meth) acrylate represented by the general formula (I) is used as a resin component in the chemically amplified radiation-sensitive resin composition In order to improve the dry etching resistance of the resist film to be formed, R ₂ preferably has an alicyclic skeleton in its structure, and is specifically represented by the following general formula (II) Things are used.

上記（Ａ）はビシクロ［２．２．１］ヘプタン、（Ｂ）はテトラシクロ［６．２．１．１^３，６．０^２，７．］ドデカン、（Ｃ）はトリシクロ［５．２．１．０^２，６］デカン、（Ｄ）はトリシクロ［４．２．１．０^３，７］ノナンと命名される。以下の説明では、上記（Ａ）〜（Ｄ）の命名法に従うものとする。

The above (A) is bicyclo [2.2.1] heptane, and (B) is tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 . ] Dodecane, (C) is named tricyclo [5.2.1.0 ^2,6 ] decane, and (D) is named tricyclo [4.2.1.0 ^3,7 ] nonane. In the following description, the nomenclature (A) to (D) is followed.

  Of the above general formula (II), the following compounds are particularly preferred.

In the present invention, after the hydroxyl group is protected with an acid-dissociable protecting group, living anionic polymerization is carried out in the presence of alkyl lithium and mineral acid salt. And after performing living anion polymerization, the above-mentioned protective group is dissociated and the target (meth) acrylic-acid type (co) polymer can be obtained.
The obtained (meth) acrylic acid copolymer can be used as a resin component in the chemically amplified radiation-sensitive resin composition. That is, the (meth) acrylic acid-based copolymer is an alkali-insoluble or hardly-alkali-soluble resin, but is dissociated by the action of an acid generated by irradiation of radiation and has an acidic group. The irradiated region is a resin that is easily soluble in alkaline developing gastric juice.
Therefore, as the acid-dissociable protecting group for the hydroxyl group, those which do not dissociate under basic conditions such as living anion polymerization and can be eliminated under acidic conditions to form a hydroxyl group can be used. As the separation condition, it is necessary to select a material under which the (meth) acrylic acid copolymer, which is the target product, does not dissociate to produce an acidic group. Examples of the filling material include acetal, aminal, silyl ether, and the like. Among them, it is preferable to use an acetal protecting group obtained by reacting an alkyl vinyl ether as a protecting group. Since such a protecting group is dissociated under relatively mild acidic conditions, the target (meth) acrylic acid copolymer requires two or more acid-dissociable groups containing this protecting group. This is because the dissociation reaction conditions after the polymerization treatment can be easily found relatively easily in order to obtain a desired polymer.
The reaction formula is shown below using (meth) acrylate represented by the general formula (I-1).

In the production method of the present invention, after the hydroxyl group is protected with a protecting group as described above, living anionic polymerization is carried out in the presence of alkyllithium and a mineral acid salt.
As the alkyl lithium to be used, alkyl lithium having 1 to 18 carbon atoms, preferably 2 to 6 carbon atoms, particularly preferably 4 carbon atoms, for example, n-butyl lithium, sec-butyl lithium or t-butyl lithium is used.
Examples of the mineral acid used in the mineral acid salt include sulfuric acid, nitric acid, boric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, perchloric acid, and carbonic acid. Hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, perchloric acid, particularly preferably hydrochloric acid is used. In addition, as the salts of these mineral acids, alkali metal salts or alkaline earth metal salts are used, and specific examples include sodium, potassium, lithium, barium, magnesium and the like. Or an alkaline earth metal halide is preferred, and specific examples include lithium chloride, lithium bromide, lithium iodide, lithium fluoride, sodium bromide, magnesium chloride, potassium chloride, potassium bromide, and the like. It is preferable to use lithium chloride.

  In the present invention, it is preferable to use a mineral acid salt of 5 equivalents or less of alkyllithium and mineral acid salt to be used with respect to alkyllithium.

  As the living anion polymerization method of the present invention, any of a method of mixing an alkyl lithium and a mineral acid salt in a monomer-containing solution or a method of mixing a monomer in a solution containing an alkyl lithium and a mineral acid salt is performed. However, the living anionic polymerization reaction is usually carried out in an organic solvent under an inert gas atmosphere such as nitrogen or argon at −100 to 50 ° C., preferably −100 to 40 ° C., more preferably −78 ° C. to Performed at room temperature.

  Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, And cycloalkanes such as norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and cumene; ethers such as tetrahydrofuran, dimethoxyethanes and diethoxyethanes. These solvents can be used alone or in combination of two or more.

  After confirming that there is no residual monomer by GPC, the living anion polymerization is terminated, and then the protective group is eliminated under acidic conditions to form a hydroxyl group having a porfluoroalkyl group at the α-position. In addition to the solvent exemplified in the living anion polymerization reaction, this reaction may be performed using hydrochloric acid, sulfuric acid, oxalic acid, in the presence of one kind or a mixture of two or more kinds of alcohols, ketones, polyhydric alcohol derivatives, water and the like. , By mixing an acid such as acetic acid.

The (meth) acrylic acid-based (co) polymer obtained in the present invention (hereinafter referred to as “resin A”) preferably has a high purity, and not only has a low content of impurities such as halogen and metal, The residual monomer or oligomer component is preferably not more than a predetermined value, for example, 0.1% by mass or less by HPLC analysis. This not only can further improve the sensitivity, resolution, process stability, pattern shape and the like as a resist obtained from the radiation-sensitive resin composition of the present invention containing the resin [A], It is possible to provide a resist that does not change with time such as sensitivity.
Therefore, the following method is mentioned as a purification method of resin [A] obtained by the above methods. As a method for removing impurities such as metals, a method in which a metal in a polymerization solution is adsorbed using a zeta potential filter, a metal is chelated and removed by washing the polymerization solution with an acidic aqueous solution such as oxalic acid or sulfonic acid. And the like. In addition, as a method of removing residual monomers and oligomer components below the specified value, liquid-liquid extraction method that removes residual monomers and oligomer components by combining water washing and an appropriate solvent, a specific molecular weight or less Refining method to remove residual monomers by coagulating resin in poor solvent by dripping polymerization solution into poor solvent And a purification method in a solid state such as washing with a poor solvent for the resin slurry separated by filtration. Moreover, you may combine these methods.

  The resin [A] synthesized by the production method of the present invention has at least a repeating unit represented by the following general formula (III), preferably general formula (III-1), particularly preferably (III-2). Is. (Hereinafter, these are collectively referred to as a repeating unit (1).)

  The repeating unit (1) may include only one type, or may include two or more types. Moreover, although it may consist only of the said repeating unit (1), and may consist of another (meth) acrylic-type repeating unit, in chemical amplification type radiation sensitive resin composition, When used as a resin component, a copolymer having other repeating units is preferable. In that case, the type and the like of the repeating unit (1) are not particularly limited, and the content of the repeating unit (1) depends on the type and the like, but is usually 5 to 90 mol% with respect to all monomers. Preferably, it is 10-80 mol%, Especially preferably, it is 10-60 mol%, More preferably, it is 10-50 mol%. When the content of the repeating unit is less than 10 mol%, the solubility of the resist in a solvent, the adhesion to the substrate, the developability of the resist, etc. tend to be lowered. On the other hand, when it exceeds 90 mol%, the resolution of the resist pattern tends to be lowered.

  As another repeating unit, the repeating unit represented by the following general formula (IV) is mentioned, for example.

Examples of the substituent R ₃ constituting the repeating unit represented by the general formula (IV) include those exemplified as the substituent R ₁ in the repeating unit (1).
Further, examples of the substituent R ₄ constituting the repeating unit, for example, organic groups shown below.

R ₁₁ in the organic group (4-1) represents a divalent organic group having a linear, branched or cyclic skeleton, in which case X represents a hydrogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group. Or R ₁₁ may be absent, in which case X represents a carboxyl group or a cyano group. R ₁₂ in the organic group (4-2) independently represents an alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or an alkyl group having 1 to 4 carbon atoms or a derivative thereof. R ₁₃ in the organic group (4-3) is an alkyl group having 1 to 6 carbon atoms or a derivative thereof, a cycloalkyl group having 5 to 10 carbon atoms or a derivative thereof, and a polycyclic alicyclic carbonization having 4 to 20 carbon atoms. A hydrogen group or a derivative thereof, or a group having a lactone ring is shown.

As the substituent R ₁₁ in the organic group (4-1), A that can form a repeating unit represented by the following general formula (V), that is, a straight chain having 1 to 4 carbon atoms or It is preferably a branched alkyl group or alkylene group (methylene group, ethylene group, propylene group, etc.), a monovalent or divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof.

As the substituent R ₁₂ in the organic group (4-2), each independently a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a straight chain having 1 to 4 carbon atoms or A branched alkyl group, and (1) at least one of R ₁₂ is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or (2) any two R ₁₂ are They are bonded to each other to form a divalent alicyclic hydrocarbon ring having 4 to 20 carbon atoms or a derivative thereof including the carbon atoms to which each is bonded, and the other R ₁₂ is 1 having 4 to 20 carbon atoms. A valent alicyclic hydrocarbon group or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. R ₁₂ is a 1-alkyl-1-cycloalkyl group, a 2-alkyl-2-adamantyl group, a (1-alkyl-1-adamantyl) alkyl group, or a (1-alkyl-1-norbornyl) alkyl group. It is preferable.

  When the resin [A] contains the repeating unit (1) and the repeating unit (IV) having the organic group (4-2) (hereinafter referred to as repeating unit (2)), the content ratio thereof is as follows. Although not particularly limited, when the total number of all repeating units constituting the resin [A] is 100 mol%, the content ratio of the repeating unit (1) is 40 to 90 mol%, preferably 40 to 80 mol%. Preferably it is 60-80 mol%. When the content ratio of the repeating unit (1) is less than 40 mol%, the developability tends to deteriorate and development defects tend to occur. On the other hand, when it exceeds 90 mol%, the resolution performance as a resist tends to be lowered. Furthermore, when the repeating unit (1) is contained in a large amount as described above, it is preferable that the resin [A] does not have a functional group derived from a lactone skeleton. When the repeating unit (1) is contained in a large amount, if the resin [A] has a functional group derived from a lactone skeleton, the solubility in a resist solvent is lowered and the pattern tends to swell.

In addition, as the substituent R ₁₃ in the organic group (4-3), a repeating unit represented by the following general formula (VI) (hereinafter referred to as a repeating unit (3)) may be formed. A functional group derived from a lactone skeleton is preferable.

  When the resin [A] contains the repeating unit (1), the repeating unit (2), and the repeating unit (3), that is, when the resin [A] contains a functional group derived from a lactone skeleton, these contents are contained. Although the ratio is not particularly limited, the content of the repeating unit (1) is preferably a small amount as compared with the case where no functional group derived from the lactone skeleton is contained. Specifically, when the total of all repeating units constituting the resin [A] is 100 mol%, the content ratio of the repeating unit (1) is 5 to 25 mol%, preferably 5 to 20 mol%. . When the content ratio of the repeating unit (1) is less than 5 mol%, the resolution performance as a resist tends to be lowered. On the other hand, when it exceeds 25 mol%, the pattern tends to swell and easily collapse.

Examples of monomers that give the above repeating unit (IV) are listed below.
(Meth) acrylic acid hydroxymethyl ester, 1- (meth) acrylic acid-2-hydroxymethyl ester, 1- (meth) acrylic acid-3-hydroxypropyl ester, 1- (meth) acrylic acid-1-fluoro-1 -Hydroxymethyl ester, 1- (meth) acrylic acid-1,1-fluoro-1-hydroxymethyl ester, 1- (meth) acrylic acid-1,2-difluoro-2-hydroxymethyl ester, 1- (meth) Acrylic acid-1,1,2,2-tetrafluoro-2-hydroxymethyl ester, 1- (meth) acrylic acid-2-trifluoromethyl-2-hydroxyethyl ester, 1- (meth) acrylic acid-2, 2-ditrifluoromethyl-2-hydroxyethyl ester,

(Meth) acrylic acid, (meth) acrylic acid-3-hydroxyadamantan-1-yl ester, (meth) acrylic acid-5 (6) -hydroxybicyclo [2.2.1] hept-2-yl ester, (Meth) acrylic acid-9 (10) -hydroxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 . ] Dodec-4-yl, (meth) acrylic acid carboxyl methyl ester, (meth) acrylic acid-2-carboxyl ethyl ester, (meth) acrylic acid-3-carboxylpropyl ester, (meth) acrylic acid-3-carboxyadamantane -1-yl ester, (meth) acrylic acid-5 (6) -carboxybicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-9 (10) -carboxytetracyclo [6. 2.1.1 ^3,6 . 0 ^2,7 . ] Dodec-4-yl ester, (meth) acrylic acid cyanomethyl ester, 1- (meth) acrylic acid-2-cyanoethyl ester, 1- (meth) acrylic acid-3-cyanopropyl ester, (meth) acrylic acid- 3-cyanoadamantan-1-yl, (meth) acrylic acid-5 (6) -cyanobicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-9 (10) -cyanotetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 . ] Dodec-4-yl ester,

(Meth) acrylic acid-t-butyl ester, (meth) acrylic acid-2-methyl-2-propyl ester, (meth) acrylic acid-2-methyl-2-butyl ester, (meth) acrylic acid-2-ethyl 2-butyl ester, (meth) acrylic acid-3-ethyl-3-butyl ester, (meth) acrylic acid-2-methyladamantan-2-yl ester, (meth) acrylic acid-2-methyl-3-hydroxy Adamantane-2-yl ester, (meth) acrylic acid-2-ethyladamantan-2-yl ester, (meth) acrylic acid-8-methyltricyclo [5.2.1.0 ^2,6 ] decane-8- Yl ester, (meth) acrylic acid-8-ethyltricyclo [5.2.1.0 ^2,6 ] decan-8-yl ester, (meth) acrylic acid-1-methyl ester Clopentyl ester, (meth) acrylic acid-1-ethylcyclopentyl ester, (meth) acrylic acid-1-methylcyclohexyl ester, (meth) acrylic acid-1-ethylcyclohexyl ester, (meth) acrylic acid-2-methylbicyclo [2.2.1] Hept-2-yl ester, (meth) acrylic acid-2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-4-methyl-tetracyclo [ 6.2.1.1 ^3,6 . 0 ^2,7 . ] Dodec-4-yl ester, (meth) acrylic acid-4-ethyl-tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 . ] Dodec-4-yl ester, (meth) acrylic acid-1-cyclohexyl-1-methylethyl ester, (meth) acrylic acid-1-bicyclo [2.2.1] hept-2-yl-1-methylethyl Ester, (meth) acrylic acid-1-tricyclo [5.2.1.0 ^2,6 ] dec-8-yl-1-methylethyl ester, (meth) acrylic acid-1-tetracyclo [6.2.1 ^.1,3,6 . 0 ^2,7 . ] Dodec-4-yl-1-methyl ethyl ester, (meth) acrylic acid-1-adamantan-1-yl-1-methyl ethyl ester, (meth) acrylic acid-1- (2 (3) -hydroxycyclopentyl) -1-methylethyl ester, (meth) acrylic acid-1- (3 (4) -hydroxycyclohexyl) -1-methylethyl ester, (meth) acrylic acid-1- (3 (4) -hydroxycycloheptyl) -1-methyl ethyl ester, (meth) acrylic acid-1- (3-hydroxyadamantan-1-yl) -1-methyl ethyl ester, (meth) acrylic acid-1,1-dicyclohexyl ethyl ester, 1,1- Dibicyclo [2.2.1] hept-2-ylethyl ester, (meth) acrylic acid-1,1-ditricyclo [5.2.1.0 ^{2, 6]} dec-8-yl ethyl ester, (meth) -1,1 acrylate di (tetracyclo ^[6.2.1.1 3,6 ^{.0 2,7.]} Dodeca-4-yl) ethyl ester, (Meth) acrylic acid-1,1-diadamantane-1-ylethyl ester,

(Meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid n-propyl ester, (meth) acrylic acid cyclopentyl ester, (meth) acrylic acid cyclohexyl ester, (meth) acrylic acid adamantane-1 -Yl ester, (meth) acrylic acid bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-7,7-dimethylbicyclo [2.2.1] hept-1-yl ester, (Meth) acrylic acid tricyclo [5.2.1.0 ^2,6 ] dec-8-yl ester, (meth) acrylic acid tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 . ] Dodec-4-yl ester;

(Meth) acrylic acid-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid-9-methoxycarbonyl-5-oxo-4 -Oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid-7-oxo-6-oxa-bicyclo [3.2.1] oct-4-yl Ester, (meth) acrylic acid-2-methoxycarbonyl-7-oxo-6-oxa-bicyclo [3.2.1] oct-4-yl ester, (meth) acrylic acid-2-oxotetrahydropyran-4- Yl ester, (meth) acrylic acid-4-methyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-ethyl-2-oxotetrahydropyran-4-yl ester, (Meth) acrylic acid-4-propyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2,2-dimethyl-5 -Oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) Acrylic acid-4,4-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5,5-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxo Tetrahydrofuran-3-yl ester, (meth) acrylic acid-5-oxotetra Drofuran-2-ylmethyl ester, (meth) acrylic acid-3,3-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-2- Ilmethyl ester and the like.

As for the repeating unit exemplified as the repeating unit (IV), only one kind may be contained in the resin [A], or two or more kinds may be contained.
The total content of the repeating unit (IV) depends on the type of the repeating unit (IV) and the like, but is usually 80 mol% or less, preferably 70 mol% or less, based on all repeating units. Preferably it is 60 mol% or less. In this case, when the total content of the repeating units (IV) exceeds 80 mol%, the adhesiveness and developability of the resist are lowered, and the effect of reducing development defects tends to be lowered. In addition, when the resin [A] has a functional group derived from a lactone skeleton, the total content of the repeating unit (IV) is preferably larger, more than 70 mol%, particularly 80 mol% or more, and more More than that may be sufficient.

  Examples of the resin [A] related to the present invention include those having the following monomer units, but the constitutional order and content ratio of the monomer units are not particularly limited.

上記すべての式において、Ｒ_１は、水素原子、メチル基、又は炭素数１〜４のパーフルオロアルキル基を示し、Ｒはメチル基又はエチル 基を示す。

In all the above formulas, R ₁ represents a hydrogen atom, a methyl group, or a perfluoroalkyl group having 1 to 4 carbon atoms, and R represents a methyl group or an ethyl group.

  Examples of the resin [A] related to the present invention include those having the following monomer units, but in these cases, in addition to the hydroxyl group having a perfluoroalkyl group at the α-position, Since the alicyclic skeleton also has a hydroxyl group, it is necessary to protect this hydroxyl group with an acid-dissociable protecting group as well.

The weight average molecular weight (hereinafter referred to as “Mw”) in terms of polystyrene by gel permeation chromatography (GPC) of the resin [A] according to the present invention is usually 1,000 to 300,000, preferably 2,000. To 200,000, more preferably 3,000 to 100,000. When Mw is less than 1,000, the heat resistance as a resist tends to be reduced. On the other hand, when it exceeds 300,000, the developability as a resist tends to be lowered.
Further, the ratio (Mw / Mn) between the Mw and the number average molecular weight (hereinafter referred to as “Mn”) simultaneously obtained by GPC is usually 1 to 5, preferably 1 to 3.
Resin [A] used for the radiation sensitive resin composition of this invention can be used individually by 1 type or in combination of 2 or more types.

When the resin [A] is used as a resin component in the chemically amplified radiation-sensitive resin composition, the composition contains a radiation-sensitive acid generator [B] (hereinafter referred to as “acid generator [B]”). .).
The acid generator [B] is a substance that generates an acid upon exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, electron beam, and X-ray.
The acid generator [B] dissociates acid-dissociable groups such as alkyladamantyl groups, t-butyl groups, and tetrahydropyranyl groups present in the resin [A] by the action of the acid generated by exposure. As a result, the exposed portion of the resist film becomes readily soluble in an alkali developer, and a positive resist pattern is formed.
Examples of the acid generator [B] include onium salt compounds, halogen-containing compounds, sulfone compounds, sulfonic acid ester compounds, and quinonediazide compounds.
Specific examples of these acid generators include those shown below.

(Onium salt compound)
Examples of onium salt compounds include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.
Preferred onium salt compounds are diphenyliodonium trifluoromethanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium dodecylbenzenesulfonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalenesulfonate, (hydroxyphenyl) benzylmethylsulfonium And toluene sulfonate.

(Halogen-containing compounds)
Examples of the halogen-containing compound include haloalkyl group-containing hydrocarbon compounds and haloalkyl group-containing heterocyclic compounds.
Preferred halogen-containing compounds are (trichloromethyl) -s such as phenyl-bis (trichloromethyl) -s-triazine, methoxyphenyl-bis (trichloromethyl) -s-triazine, naphthyl-bis (trichloromethyl) -s-triazine. -Triazine derivatives, 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane and the like.

(Sulfone compound)
Examples of the sulfone compound include β-ketosulfone, β-sulfonylsulfone, and α-diazo compounds thereof.
Preferred sulfone compounds are phenacylphenylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane, bis (phenylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, 4-trisphenacylsulfone and the like.

(Sulfonate compound)
Examples of the sulfonate compound include alkyl sulfonate, haloalkyl sulfonate, aryl sulfonate, imino sulfonate, and imide sulfonate.
Preferred sulfonic acid ester compounds include benzoin tosylate, pyrogallol tristriflate, nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, N- (trifluoromethylsulfonyloxy) maleimide, N- (trifluoromethylsulfonyl) Oxy) phthalimide, N- (trifluoromethylsulfonyloxy) -bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (trifluoromethylsulfonyloxy) naphthylimide, N- (Camphanylsulfonyloxy) naphthylimide and the like.

The said acid generator [B] can be used individually by 1 type or in combination of 2 or more types.
The content of the acid generator [B] is usually 0.1 to 20 parts by mass, preferably 0.1 to 15 parts by mass, more preferably 0.1 to 100 parts by mass of the resin [A]. 10 parts by mass. By setting it as such content, the sensitivity and developability as a resist can be sufficiently ensured. In addition, when the content of the acid generator [B] is less than 0.1 parts by mass, the sensitivity and developability tend to decrease. On the other hand, when the content exceeds 10 parts by mass, the transparency to radiation decreases, A rectangular resist pattern tends to be difficult to obtain.

Various additives can be contained in the chemically amplified radiation-sensitive resin composition of the present invention. Among them, an acid diffusion control agent [C] that controls the diffusion phenomenon in the resist film of the acid generated from the acid generator [B] by exposure and suppresses unnecessary chemical reaction in the non-exposed region is blended. It is preferable.
The acid diffusion controller is preferably a nitrogen-containing organic compound whose basicity does not change by exposure or heat treatment during the resist pattern formation step.

  Although it does not specifically limit as said nitrogen-containing organic compound, The compound represented by the following general formula (VII), a quaternary ammonium hydroxide compound, an amide group containing compound, a urea compound, a nitrogen-containing heterocyclic compound, etc. are mentioned.

式中、各Ｒは互いに独立に水素原子、置換あるいは非置換の直鎖状、分岐状又は環状のアルキル基、置換あるいは非置換のアリール基、又は置換あるいは非置換のアラルキル基を示し、Ｘは２価の有機基を示し、ｎは０〜２の整数を示す。

In the formula, each R independently represents a hydrogen atom, a substituted or unsubstituted linear, branched or cyclic alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and X represents A divalent organic group is shown, and n is an integer of 0-2.

When the substituent R constituting the general formula (VII) has a functional group, examples thereof include a hydroxyl group. These may be a single type or a combination of two or more types.
In the above general formula (VII), the case where n = 0 is referred to as “nitrogen-containing compound (a)”. The case where n = 1 to 2 is referred to as “nitrogen-containing compound (b)”. Furthermore, a polyamino compound or polymer having 3 or more nitrogen atoms is referred to as “nitrogen-containing compound (c)”.

  Examples of the nitrogen-containing compound (a) include mono- (cyclo) alkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, cyclohexylamine; -Butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, cyclohexylmethylamine, dicyclohexylamine, etc. Of di (cyclo) alkylamines; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octyl Amine, tri-n-nonylamine, tri-n-decylamine, cyclohexane Tri (cyclo) alkylamines such as sildimethylamine, dicyclohexylmethylamine, tricyclohexylamine; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, Aromatic amines such as 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline, diphenylamine, triphenylamine, naphthylamine and the like can be mentioned.

  Examples of the nitrogen-containing compound (b) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, and tetramethylenediamine. 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzenetetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4 ′ -Diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-amino Phenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) 2- (4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1- Methylethyl] benzene, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether and the like.

  Examples of the nitrogen-containing compound (c) include polyethyleneimine, polyallylamine, 2-dimethylaminoethylacrylamide polymer, and the like.

  Examples of the quaternary ammonium hydroxide compound used as the acid diffusion controller [C] other than the compound represented by the general formula (VII) include tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetra-n-propyl. Ammonium hydroxide, tetra-n-butylammonium hydroxide, etc. are mentioned.

  Examples of the amide group-containing compound include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-butoxy. Carbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N′N′-tetra-t-butoxycarbonylhexamethylenedia N, N′-di-t-butoxycarbonyl-1,7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxy Carbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminododecane, N, N ′ -Di-t-butoxycarbonyl-4,4'-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole Nt-butoxycarbonyl group-containing amino compounds such as formamide, N-methylformamide, N, N-dimethyl Formamide, acetamide, N- methylacetamide, N, N- dimethylacetamide, propionamide, benzamide, pyrrolidone, N- methylpyrrolidone and the like.

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tri-n-butylthiourea. Is mentioned.
Examples of the nitrogen-containing heterocyclic compound include imidazoles such as imidazole, 4-methylimidazole, 1-benzyl-2-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, and 2-phenylbenzimidazole; pyridine, 2 -Methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 4 -Pyridines such as hydroxyquinoline, 8-oxyquinoline and acridine; piperazines such as piperazine and 1- (2-hydroxyethyl) piperazine, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, 3-piperidine Roh-1,2-propanediol, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane.

  Of these nitrogen-containing organic compounds, amide group-containing compounds and nitrogen-containing heterocyclic compounds are preferred. The amide group-containing compound is preferably an Nt-butoxycarbonyl group-containing amino compound, and the nitrogen-containing heterocyclic compound is preferably an imidazole. Moreover, the said nitrogen-containing organic compound can be used individually by 1 type or in combination of 2 or more types.

The compounding amount of the acid diffusion controller [C] is usually 0.001 to 15 parts by mass, preferably 0.01 to 10 parts by mass, and more preferably 0.001 parts by mass with respect to 100 parts by mass of the resin [A]. 01 to 5 parts by mass. By setting it as such a compounding quantity, the storage stability of the radiation sensitive resin composition obtained improves further. In addition, the resolution as a resist is further improved, and a change in the line width of the resist pattern due to fluctuations in the holding time (PED) from exposure to development processing can be suppressed, and a composition having excellent process stability can be obtained. It is done.
In addition, when the compounding quantity of the said acid diffusion control agent [C] exceeds 15 mass parts, there exists a tendency for the sensitivity as a resist and the developability of an exposure part to fall. On the other hand, if it is less than 0.001 part by mass, the pattern shape and dimensional stability as a resist may be lowered depending on the process conditions.

  The preferred content ratios of the resin [A], the acid generator [B] and the acid diffusion controller [C] in the radiation-sensitive resin composition of the present invention are as follows. That is, with respect to 100 parts by mass of the resin [A], the acid generator [B] is usually 0.1 to 20 parts by mass, and the acid diffusion controller [C] is 0.001 to 15 parts by mass, preferably Is 0.1 to 15 parts by mass of the acid generator [B], 0.01 to 10 parts by mass of the acid diffusion controller [C], more preferably 0.1 to 10 parts of the acid generator [B]. Parts by mass, the acid diffusion controller [C] is 0.01 to 5 parts by mass

The radiation-sensitive resin composition of the present invention can be blended with an additive exhibiting an action of further improving dry etching resistance, pattern shape, adhesion to the substrate, and the like. This additive may contain an acid dissociable functional group, or may not contain it. Examples thereof include 1-adamantanecarboxylic acid t-butyl, 1-adamantanecarboxylic acid t-butoxycarbonylmethyl, 1-adamantanecarboxylic acid α-butyrolactone ester, 1,3-adamantane dicarboxylic acid di-t-butyl, Adamantane derivatives such as t-butyl adamantane acetate, t-butoxycarbonylmethyl 1-adamantane acetate, di-t-butyl 1,3-adamantane diacetate, 2,5-dimethyl-2,5-di (adamantylcarbonyloxy) hexane Kind;
Deoxycholate t-butyl, deoxycholate t-butoxycarbonylmethyl, deoxycholate 2-ethoxyethyl, deoxycholate 2-cyclohexyloxyethyl, deoxycholate 3-oxocyclohexyl, deoxycholate tetrahydropyranyl, deoxychol Deoxycholic acid esters such as acid mevalonolactone ester;
Lithocholic acid t-butyl, lithocholic acid t-butoxycarbonylmethyl, lithocholic acid 2-ethoxyethyl, lithocholic acid 2-cyclohexyloxyethyl, lithocholic acid 3-oxocyclohexyl, lithocholic acid tetrahydropyranyl, lithocholic acid mevalonolactone ester, etc. Lithocholic acid esters;
Alkyl carboxylic acid esters such as dimethyl adipate, diethyl adipate, dipropyl adipate, di-n-butyl adipate, di-t-butyl adipate;
Etc. Of these, t-butyl 1-adamantanecarboxylate, di-t-butyl 1,3-adamantanedicarboxylate, t-butyl 1-adamantaneacetate, 2,5-dimethyl-2,5-di (adamantylcarbonyloxy) Hexane, deoxycholate t-butyl, deoxycholate t-butoxycarbonylmethyl, lithocholic acid t-butyl, lithocholic acid t-butoxycarbonylmethyl, and di-n-butyl adipate are preferred. Moreover, these can be used individually by 1 type or in combination of 2 or more types.

  The amount of the additive is usually 50 parts by mass or less, preferably 1 to 30 parts by mass with respect to 100 parts by mass of the resin [A]. When the blending amount of the additive exceeds 50 parts by mass, the heat resistance as a resist tends to decrease.

In addition, the radiation-sensitive resin composition of the present invention can be blended with a surfactant exhibiting an effect of improving coatability, developability and the like. Any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant can be used, and among these, a nonionic surfactant is preferable. Examples include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate. Etc. In addition, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (manufactured by Tochem Products), Megafax F171, F173 (manufactured by Dainippon Ink & Chemicals), Florard FC430, FC431 (Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Co., Ltd.), etc. . The said surfactant can be used individually by 1 type or in combination of 2 or more types.
Moreover, the compounding quantity of the said surfactant is 2 mass parts or less normally with respect to a total of 100 mass parts of resin [A] and an acid generator [B], Preferably it is 0.001-2 mass parts.

Moreover, the radiation sensitive resin composition of this invention can be mix | blended with the sensitizer which shows the effect | action which improves a sensitivity. Examples thereof include carbazoles, benzophenones, rose bengals, anthracenes, phenols and the like. Moreover, these can be used individually by 1 type or in combination of 2 or more types.
The compounding quantity of the said sensitizer is 50 mass parts or less normally with respect to 100 mass parts of resin [A], Preferably it is 1-20 mass parts.

  Still other additives blended in the radiation sensitive resin composition of the present invention include antihalation agents, adhesion assistants, storage stabilizers, antifoaming agents, and the like.

The radiation-sensitive resin composition of the present invention can be prepared by dissolving resin [A], acid generator [B] and the like in a solvent or the like. As this solvent, 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-methyl-2-pentanone, 3,3-dimethyl-2-butanone Linear or branched ketones such as 2-heptanone and 2-octanone;
Cyclic ketones such as cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, isophorone;
Propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-i-propyl ether acetate, propylene glycol mono-n-butyl ether acetate, propylene glycol mono-i-butyl ether acetate Propylene glycol monoalkyl ether acetates such as propylene glycol mono-sec-butyl ether acetate, propylene glycol mono-t-butyl ether acetate;

Methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, n-propyl 2-hydroxypropionate, i-propyl 2-hydroxypropionate, n-butyl 2-hydroxypropionate, i-butyl 2-hydroxypropionate, Alkyl 2-hydroxypropionates such as sec-butyl 2-hydroxypropionate and t-butyl 2-hydroxypropionate;
Alkyl 3-alkoxypropionates such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate;

alcohols such as n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclohexanol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, Alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, etc. ;
Aromatic solvents such as toluene and xylene;
Ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3 -Methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate, ethyl pyruvate, N-methyl Pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, benzyl ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, caproic acid, caprylic acid, 1-octanol, 1-nona Lumpur, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, .gamma.-butyrolactone, ethylene carbonate and propylene carbonate.

  Of these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, and γ-butyrolactone are preferable. Moreover, the said solvent can be used individually by 1 type or in combination of 2 or more types.

  In general, the radiation-sensitive resin composition of the present invention is prepared by dissolving each component in a solvent so that the total solid concentration of all components is usually 3 to 50% by mass, preferably 5 to 25% by mass. Thereafter, it is obtained by, for example, filtering with a filter having a pore diameter of about 0.2 μm.

(Method for forming resist pattern)
When forming a resist pattern using the radiation-sensitive resin composition of the present invention, the composition is coated with a silicon wafer or aluminum by a coating means such as spin coating, cast coating, roll coating or spray coating. A coating film is formed by coating on a substrate such as a wafer, and the coating film is formed so that a predetermined resist pattern is formed after heat treatment (hereinafter referred to as “PB”) in advance. To expose. The radiation used at this time is far ultraviolet rays such as ultraviolet rays, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), EUV (extreme ultraviolet rays, wavelength 13 nm, etc.). And charged particle beams such as electron beams, and X-rays such as synchrotron radiation. Of these, deep ultraviolet rays and electron beams are preferred. Moreover, exposure conditions, such as exposure amount, are suitably selected according to the compounding composition of a radiation sensitive resin composition, the kind of each additive, etc.

In order to stably form a high-precision fine pattern, heat treatment (hereinafter referred to as “PEB”) is usually performed after exposure. By this PEB, the dissociation reaction of the acid dissociable functional group in the resin [A] proceeds smoothly. Although the heating conditions for PEB vary depending on the composition of the radiation sensitive resin composition, the temperature is usually 30 to 200 ° C., preferably 50 to 170 ° C., and the time is 0.1 to 5 minutes, preferably 0. 2-3 minutes.
In order to maximize the potential of the radiation-sensitive resin composition of the present invention, an organic or inorganic antireflection film is used on a substrate to be used, as disclosed in Japanese Patent Publication No. 6-12458. May be formed. In order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film may be provided on the resist film as disclosed in JP-A-5-188598.
Next, by developing the exposed resist film, a predetermined resist pattern is formed.

Although it does not specifically limit as a developing solution used for image development, Sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia water, ethylamine, n-propylamine, diethylamine, di-n-propyl Amine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo -[4.3.0] -5-Alkaline aqueous solution in which at least one kind of alkaline compound such as nonene is dissolved may be mentioned. As the alkaline compound, tetramethylammonium hydroxide is preferable.
Moreover, the density | concentration of the alkaline compound in the said alkaline aqueous solution is 10 mass% or less normally. In this case, if the concentration of the alkaline compound exceeds 10% by mass, the unexposed area may be dissolved in the developer, which is not preferable.

  An organic solvent can also be added to the developer. Examples thereof include linear, branched or cyclic ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, 2,6-dimethylcyclohexanone; methyl alcohol, Alcohols such as ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, 1,4-hexanedimethylol; tetrahydrofuran And ethers such as dioxane; esters such as ethyl acetate, n-butyl acetate, i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonitrile, acetone, dimethylformamide, and the like.These organic solvents can be used singly or in combination of two or more.

The compounding amount of the organic solvent is usually 100 parts by mass or less, preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the developer before compounding the organic solvent. When the blending amount of the organic solvent exceeds 100 parts by mass, the developability is lowered, and there is a possibility that the development residue in the exposed area increases. Further, an appropriate amount of a surfactant or the like can be further added to the developer.
In addition, after developing with the developing solution which consists of alkaline aqueous solution, it is preferable to wash | clean and dry with water.

Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Here, the part is based on weight unless otherwise specified.
Each measurement and evaluation in Examples and Comparative Examples was performed as follows.
<Mw>
Using a GPC column (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, monodisperse polystyrene as the standard under the analysis conditions of flow rate 1.0 ml / min, elution solvent tetrahydrofuran, column temperature 40 ° C. Measured by gel permeation chromatography (GPC).
<sensitivity>
Regarding Examples and Comparative Examples, a substrate having a 770A ARC29A (Nissan Chemical Co., Ltd.) film formed on the wafer surface was used, and the composition was applied onto the substrate by spin coating, and then on a hot plate at 100 ° C. for 90 seconds. A resist film having a thickness of 0.20 μm formed by PB was exposed using a full-field reduction projection exposure apparatus S306C (numerical aperture 0.75) manufactured by Nikon through a mask pattern. Thereafter, PEB was performed at 120 ° C. for 90 seconds, and then developed with a 2.38 wt% TMAH aqueous solution at 25 ° C. for 60 seconds, washed with water, and dried to form a positive resist pattern. At this time, an exposure amount formed in a one-to-one line-and-space with a line width of 100 nm is defined as an optimum exposure amount, and the optimum exposure amount is set as a line width formed through a one-to-one line-and-space mask having a dimension of 100 nm. “Sensitivity”.
(resolution)
The dimension of the smallest resist pattern that can be resolved at the optimum exposure amount is defined as the resolution.
<Line edge roughness (LER)>
When observing the 100 nm 1L / 1S pattern resolved at the optimal exposure dose, the line width is observed at an arbitrary point when observing from the top of the pattern with Hitachi SEM: S9220, and the measurement variation is evaluated with 3 sigma. did.

(Monomer Synthesis Example) After dissolving 0.5 g of pyridinium p-toluenesulfonate and 15 g of the following compound (M-3) in 100 ml of dehydrated ethyl acetate, 4 g of ethyl vinyl ether was added at room temperature. Stir for 16 hours. Thereafter, 0.5 g of triethylamine was added to stop the reaction, and after washing with a separatory funnel, the solvent and excess ethyl vinyl ether were removed with an evaporator. The obtained oily compound was recrystallized from ethyl acetate / hexane. Yield 12.5 g (Yield 69.4%)

When the obtained crystal was confirmed using IR, the peak of the hydroxyl group disappeared, and it was confirmed that all the hydroxyl groups had a protecting group. This is designated as Compound (M′-3).

(Resin Synthesis Example) 98.62 g (70 mol%) of the above compound (M′-3) and 17.82 g (30 mol%) of the following compound (M-2) are dissolved in 1000 g of dehydrated THF, and dry nitrogen is added for 30 minutes. Bubbled. Then, it is cooled to −78 ° C. using a dry ice methanol bath, 0.33 g of lithium chloride and 0.42 g of n-butyl lithium (in terms of n-butyl lithium using a 1M hexane solution) are added, and the temperature is kept at −78 ° C. for 4 hours. And stirred. After gradually returning to room temperature over 1 hour, an excess amount of methanol was added to quench the anion. 50 g of 5% oxalic acid aqueous solution was added to the obtained THF solution and stirred at room temperature for 4 hours. Thereafter, reprecipitation into an excessive amount of water was repeated three times by dissolving in 100 g of THF again and reprecipitation into an excessive amount of water. Thereafter, the resultant was dried at 60 ° C. for 17 hours to obtain 52 g of a white powdery resin. The yield was 52%. The obtained resin had Mw of 14500 and Mw / Mn = 1.2. As a result of analysis by 13CNMR, the content of the repeating unit consisting of compound (M-3) and compound (M-2) was 70. It was 2 / 29.8 (mol%). Moreover, decomposition | disassembly of the repeating unit derived from M-2 was not seen at this time. This resin is referred to as “resin (A-1)”. Similarly, polymers A-2 to A-5 were synthesized using the following compounds (M-4), (M-5) and (M-6). The content of repeating units, the weight average molecular weight, and Mw / Mn of each resin were as follows. A-2: (M-3) / (M-2) = 50.5 / 49.5 Mw = 6500, Mw / Mn = 1.1 A-3 (M-3) / (M-2) / (M -4) = 50.2 / 15.0 / 34.8 Mw = 9500, Mw / Mn = 1.2A-4: (M-3) / (M-5) = 45.5 / 54.5 Mw = 7500, Mw / Mn = 1.2A-5: (M-3) / (M-6) / (M-4) = 10.5 / 40.5 / 49.0 Mw = 8600, Mw / Mn = 1 .2

(Comparative synthesis example of resin: synthesis by radical polymerization method) 82.18 g (70 mol%) of the above compound (M-3) and 17.82 g (30 mol%) of the above compound (M-2) are dissolved in 200 g of 2-butanone. Further, 3.21 g of tolyl was added to azobisisobutyro and dissolved to prepare a monomer solution, which was then prepared in a dropping funnel. Thereafter, 100 g of 2-butanone was placed in a 500 ml three-necked flask, purged with nitrogen for 30 minutes, heated to 80 ° C. with stirring, and the monomer solution was dropped from the dropping funnel over 2 hours. It was made to react for 6 hours after dripping was started. After completion of the polymerization, it was cooled to 30 ° C. or lower. Next, it was poured into 4000 g of n-hexane to precipitate a white solid. After filtering this off, the resulting white solid was washed twice with 400 g of n-hexane. It was filtered and dried at 60 ° C. for 17 hours to obtain 72 g of a white powdery resin. The yield was 72%. The obtained resin had Mw of 11500, and the content of the repeating unit consisting of the compound (M-3) and the compound (M-2) was 69.5 / 30.5 (mol%). This resin is referred to as “resin (R-1)”.

(Preparation of resist composition and pattern formation: Examples 1 to 5 and comparative example) Various evaluations were performed on the compositions composed of the components shown in Table 1. The evaluation results are shown in Table 2. In Table 1, components other than the resin are as follows.
Acid generator (B): Triphenylsulfonium nonafluoro-n-butanesulfonate Acid diffusion controller (C): Nt-butoxycarbonyl-2-phenylbenzimidazole Solvent (D): Propylene glycol monomethyl ether acetate

  As is clear from Table 2, by using a resin made of a copolymer produced by the production method of the present invention, an improvement in resolution and a reduction in line edge roughness (LER) were achieved.

Claims (2)

A method for producing a (meth) acrylic acid copolymer used in a chemically amplified radiation-sensitive resin composition , comprising at least one (meth) acrylate having a perfluoroalkyl group at the α-position of a hydroxyl group and a derivative thereof using the above monomers, the hydroxyl group of the monomer, was protected with alkyl vinyl ether, and performing living anion polymerization in the presence of an alkyl lithium and mineral (meth) acrylic acid-based copolymer polymer Synthesis method. After the living anionic polymerization process according to claim 1, wherein the (meth) acrylic acid copolymer, characterized in that to detach the protective group described above.