JP4645153B2 - Radiation sensitive resin composition - Google Patents

Description

  The present invention relates to a radiation-sensitive resin composition. More specifically, the present invention relates to a radiation-sensitive resin composition that can be suitably used as a chemically amplified resist useful for microfabrication using far ultraviolet rays such as KrF excimer laser or ArF excimer laser. The present invention relates to a resin composition.

  In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, development of lithography technology that enables microfabrication on the order of sub-half micron (0.4 μm or less) has recently been advanced. In the near future, it is said that a sub-quarter micron (0.20 μm or less) level microfabrication technology will be required.

  In order to enable microfabrication at the sub-quarter micron level, 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, deep ultraviolet rays typified by an excimer laser, X-rays, and electron beams. Among these, a KrF excimer laser or an ArF excimer is particularly used. Lasers are drawing attention.

  As a radiation-sensitive resin composition suitable for irradiation with such an excimer laser, a radiation-sensitive acid generator that generates an acid upon irradiation with a component having an acid-dissociable functional group (hereinafter referred to as “exposure”). Many compositions (hereinafter referred to as “chemically amplified radiation-sensitive compositions”) that utilize the interaction with the above have been proposed.

  Examples of such a chemically amplified radiation-sensitive composition include a composition containing a polymer having a t-butyl ester group of carboxylic acid or a t-butyl carbonate group of phenol and a radiation-sensitive acid generator. It has been proposed (see Patent Document 1). In this composition, the t-butyl ester group or t-butyl carbonate group present in the polymer is dissociated by the action of an acid generated by exposure, and the polymer is an acidic group consisting of a carboxyl group or a phenolic hydroxyl group. As a result, a phenomenon that the exposed region of the resist film becomes easily soluble in an alkali developer is utilized.

  By the way, many of the conventional chemically amplified radiation-sensitive compositions are based on phenolic resins, but in the case of such resins, since far ultraviolet rays are absorbed due to the aromatic ring, exposure is performed. There is a drawback that the irradiated radiation cannot sufficiently reach the lower layer part of the resist film, so that the exposure amount is higher in the upper layer part of the resist film and smaller in the lower layer part, and the resist pattern after development becomes narrower in the upper part and lower in the lower part There was a problem that it became a thick trapezoid and a sufficient resolution could not be obtained. In addition, when the resist pattern after development has a trapezoidal shape, a desired dimensional accuracy cannot be achieved in the next process, that is, etching or ion implantation, which is a problem. In addition, if the shape of the upper part of the resist pattern is not rectangular, there is a problem that the resist disappearing rate by dry etching is increased and it becomes difficult to control the etching conditions.

  The shape of the resist pattern can be improved by increasing the radiation transmittance of the radiation-sensitive resin composition. For example, (meth) acrylate resins typified by polymethyl methacrylate are highly transparent to deep ultraviolet rays and are highly preferred from the viewpoint of radiation transmittance. Chemical amplification using methacrylate resins A type radiation sensitive resin composition has been proposed (see Patent Document 2). However, although this composition is excellent in terms of microfabrication performance, since it does not have an aromatic ring, it has a drawback of low dry etching resistance. In this case as well, it is difficult to perform highly accurate etching. In addition to the radiation transmittance, development of a chemically amplified radiation-sensitive resin composition excellent in dry etching resistance is desired.

  On the other hand, in order to improve dry etching resistance without impairing transparency to far ultraviolet rays, a method of introducing an alicyclic group instead of an aromatic ring is known. A chemically amplified radiation-sensitive resin composition using a (meth) acrylate resin has been proposed (see Patent Document 3). For the purpose of improving developability and adhesion to the substrate, a radiation-sensitive resin composition containing a resin having a carboxyl group introduced at the terminal has also been proposed (see Patent Document 4).

  However, when a higher degree of integration is required in the semiconductor field, a radiation-sensitive resin composition that is a resist is required to have better resolution. At the same time, as the miniaturization progresses, the demand for reducing the line edge roughness of the pattern has increased. Further, along with miniaturization, it has been required to reduce a margin with respect to process conditions, for example, density / iso bias of a pattern. With the progress of miniaturization in the semiconductor industry, there is an urgent need to develop a radiation-sensitive resin composition that satisfies such conditions as excellent resolution, low pattern line edge roughness, and low pattern density dependency.

JP-B-2-27660 JP-A-4-226461 JP-A-7-234511 Japanese Patent Laid-Open No. 10-55069

  The present invention is a radiation-sensitive resin composition having high transparency to radiation, excellent basic properties as a resist such as sensitivity, resolution, dry etching resistance, pattern shape, etc., high resolution performance, and low pattern line edge roughness. It provides things.

  The present invention is excellent in basic physical properties as a resist when a resin comprising a combination of two specific types of repeating units and a specific end group is used as a resist together with a radiation-sensitive acid generator, and particularly, the line edge roughness is improved. It is based on finding out that it is done. That is, according to the present invention, the following radiation-sensitive resin composition is provided.

(A) A resin having a group represented by the following general formula (1) at at least one end of a molecular chain, hardly soluble or insoluble in alkali, and easily soluble in alkali by the action of an acid. formula repeating unit represented by (2), and the following general formula (3) a resin having a repeating unit represented by, and (B) a radiation-sensitive acid generator to that radiation sensitive resin composition containing a.

〔式（１）中、−Ｘ−は−Ｓ−Ｒ¹−で表される２価の基を示し、Ｒ¹は置換基を有することができる炭素数１〜２０の２価の炭化水素基を示す。〕

Wherein (1), -X- is -S-R ¹ - represents a divalent group represented by a divalent hydrocarbon group having a carbon number of 1 to 20 R ¹ is capable of having a substituent Indicates. ]

〔式（２）中、Ｒ^２は水素原子又はメチル基を示し、Ｒ^３、Ｒ^４及びＲ^５は、以下の（ｉ）の条件を満たす基である。
（ｉ）Ｒ^３、Ｒ^４及びＲ^５のいずれか２つが互いに結合して、それぞれが結合している炭素原子も含めて、シクロペンチル基、もしくはシクロヘキシル基、またはその誘導体を形成し、残りの１つが炭素数１〜４の直鎖状もしくは分岐状のアルキル基である。〕

[In formula (2), ^{R 2} represents a hydrogen atom or a methyl ^group, R 3, ^{R 4} and ^{R 5} are satisfying group of the following (i).
(I) Any two of R ³ , R ⁴ and R ⁵ are bonded to each other to form a cyclopentyl group, a cyclohexyl group, or a derivative thereof including the carbon atoms to which each is bonded, and the remaining 1 One is a straight-chain or branched alkyl group having a carbon number of 1-4. ]

〔式（３）中、Ｒ^６は水素原子又はメチル基を示し、Ｒ^７は、水素原子、炭素数１〜４の直鎖状あるいは分岐状のアルキル基、炭素数１〜４の直鎖状あるいは分岐状のアルコキシ基を表す。〕

In [formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, 1 to 4 carbon atoms linear Or a branched alkoxy group is represented. ]

  In the present invention, the radiation-sensitive resin composition preferably further contains (C) an acid diffusion controller.

  Since the radiation sensitive resin composition of the present invention contains the component (A) and the component (B), and particularly contains the resin having a specific repeating unit and a specific terminal group as the component (A), It is excellent in basic resist performance such as resolution, pattern profile, and line edge roughness (LER) characteristics.

  Hereinafter, embodiments of the present invention will be specifically described, but the present invention is not limited to the following embodiments, and is based on ordinary knowledge of a person skilled in the art without departing from the spirit of the present invention. It should be understood that changes, improvements, etc. may be added as appropriate.

[(A) Resin component]
The resin (hereinafter referred to as “resin (A)”) as the component (A) is a group represented by the following general formula (1) at one or both ends of the molecular chain (hereinafter referred to as “terminal group (1)”. )).

〔式（１）中、−Ｘ−は−Ｓ−Ｒ¹−で表される２価の基を示し、Ｒ¹は置換基を有することができる炭素数１〜２０の２価の炭化水素基を示す。〕

Wherein (1), -X- is -S-R ¹ - represents a divalent group represented by a divalent hydrocarbon group having a carbon number of 1 to 20 R ¹ is capable of having a substituent Indicates. ]

In the general formula (1), examples of the divalent hydrocarbon group having 1 to 20 carbon atoms of R ¹ include a methylene group, an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, a 1,2-butylene group, Alkylene groups such as 1,3-butylene group, 2,3-butylene group, pentamethylene group and hexamethylene group; alkylidene groups such as ethylidene group, propylidene group, i-propylidene group, butylidene group, pentylidene group and hexylidene group; 1,2-cyclopentylene group, 1,3-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclohexylene group, 1,4-cyclohexylene group, 1,2-cycloheptylene group, 1 , Cycloalkylene groups such as 1,3-cycloheptylene group, 1,4-cycloheptylene group; 1,2-phenylene group, 1,3-phenylene group, , 4-phenylene, 2,3-tolylene, 2,4-tolylene, 2,5-tolylene, 1,4-naphthylene, etc .; o-xylylene, m-xylylene, p- And aralkylene groups such as a xylylene group.

  Examples of the substituent for these hydrocarbon groups include -CN, -OH, -C (= O) R (wherein R represents an alkyl group having 1 to 4 carbon atoms), -OR ( In formula, R shows a C1-C4 alkyl group.) Etc. can be mentioned. Here, as the alkyl group having 1 to 4 carbon atoms of each R, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, Examples thereof include a t-butyl group. These substituents can be present at appropriate positions of the hydrocarbon group.

  Preferable specific examples of the terminal group (1) include a residue derived from a chain transfer agent described later. That is, a preferred specific example of the compound represented by the general formula (5) described later functions as a chain transfer agent, and examples thereof include a terminal group in the case of forming a terminal group.

  Resin (A) is hardly soluble or insoluble in alkali, and becomes easily soluble in alkali by the action of an acid. By having such characteristics, it can be suitably used as a resist material by combining with the radiation-sensitive acid generator as the component (B).

  Here, “alkali hardly soluble or insoluble” means an alkali development processing condition employed when a resist pattern is formed from a resist film formed from the radiation-sensitive resin composition of the present invention containing the resin (A). Below, when the film formed only from resin (A) is developed instead of the resist film, it means the property that 50% or more of the initial film thickness of the film remains after the development process. Further, “becomes readily alkali-soluble by the action of an acid” means that the alkali employed when forming a resist pattern from a resist film formed from the radiation-sensitive resin composition of the present invention containing the resin (A). It means the property that 90% or more of the initial film pressure of the film disappears after the development process when the film formed only from the dissolved resin (A) is developed after the action of the acid under the development process condition.

  In order to exhibit the characteristics as described above, the resin (A) has a repeating unit represented by the following general formula (2) (hereinafter referred to as “repeating unit (2)”).

〔式（２）中、Ｒ^２は水素原子又はメチル基を示し、Ｒ^３、Ｒ^４及びＲ^５は、以下の（ｉ）の条件を満たす基である。
（ｉ）Ｒ^３、Ｒ^４及びＲ^５のいずれか２つが互いに結合して、それぞれが結合している炭素原子も含めて、シクロペンチル基、もしくはシクロヘキシル基、またはその誘導体を形成し、残りの１つが炭素数１〜４の直鎖状もしくは分岐状のアルキル基である。〕

[In formula (2), ^{R 2} represents a hydrogen atom or a methyl ^group, R 3, ^{R 4} and ^{R 5} are satisfying group of the following (i).
(I) Any two of R ³ , R ⁴ and R ⁵ are bonded to each other to form a cyclopentyl group, a cyclohexyl group, or a derivative thereof including the carbon atoms to which each is bonded, and the remaining 1 One is a straight-chain or branched alkyl group having a carbon number of 1-4. ]

Specific examples of the linear or branched alkyl group having 1 to 4 carbon atoms of R ³ , R ⁴ and R ⁵ in the general formula (2) include a methyl group, an ethyl group, an n-propyl group, and i-propyl. Group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like .

Specific examples of the monomer that gives the repeating unit (2) include ( meth) acrylic acid-1-methylcyclopentyl ester, (meth) acrylic acid-1-ethylcyclopentyl ester, (meth) acrylic acid-1-methylcyclohexyl. esters, (meth) -1-ethyl-cyclohexyl ester le acrylic acid.

  The resin (A) has a repeating unit represented by the general formula (3) (hereinafter referred to as “repeating unit (3)”).

〔式（３）中、Ｒ⁶は水素原子又はメチル基を示し、Ｒ⁷は、水素原子、炭素数１〜４の直鎖状あるいは分岐状のアルキル基、炭素数１〜４の直鎖状あるいは分岐状のアルコキシ基を表す。〕

In [formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, 1 to 4 carbon atoms linear Or a branched alkoxy group is represented. ]

Specific examples of the linear or branched alkyl group having 1 to 4 carbon atoms in R ⁷ of the general formula (3) include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n- Examples thereof include a butyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a t-butyl group. Examples of the linear or branched alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, and n- A propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group and the like can be mentioned.

Specific examples of the monomer that gives the repeating unit (3) include (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 and the like.

  As described above, the resin (A) has all of the terminal groups (1) and the repeating units (2) and (3), so that it is combined with the radiation-sensitive acid generator that is the component (B) described later, A radiation-sensitive resin composition having excellent resolution, pattern profile, and line edge roughness (LER) characteristics can be obtained.

Resin (A) can contain other repeating units in addition to repeating units (2) and (3). Specific examples of monomers that give other repeating units include (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-hydroxy Ethyl 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 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-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-oxotetrahydrofuran-3-yl ester, (Meth) acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-3,3-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-4,4- And dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester That.

  The other repeating units can be contained in the resin (A) in an amount of 60 mol% or less based on the total amount of the repeating units (2) and (3) and the other repeating units.

  The resin (A) preferably has 10 to 80 mol%, more preferably 20 to 70 mol%, and particularly preferably 30 to 65 mol% of the repeating unit (2) with respect to all repeating units. The repeating unit (3) is preferably 10 to 60 mol%, more preferably 20 to 55 mol%, particularly preferably 30 to 50 mol%. Moreover, it is preferable to have another repeating unit 0-50 mol%, Furthermore, 0-40 mol%, Especially 5-30 mol%. If the content of the repeating unit (2) is too low, the resolution tends to deteriorate, and if it is too high, the developability tends to decrease. If the content of the repeating unit (3) is too high, the resin tends to be insoluble in the solvent.

  The weight average molecular weight in terms of polystyrene (hereinafter referred to as “Mw”) obtained by gel permeation chromatography (GPC) of the resin (A) is preferably 3,000 to 50,000, more preferably 5,000 to 30. 1,000, particularly preferably 5,000 to 10,000. If the Mw of the resin (A) is too small, the difference in the alkali dissolution rate between the exposed area and the unexposed area tends to be small, and the resolution tends to decrease. There is a tendency for the sensitivity to be lowered. The ratio (Mw / Mn) of Mw obtained by gel permeation chromatography (GPC) of the resin and the number average molecular weight in terms of polystyrene (hereinafter referred to as “Mn”) is preferably 1 to 6, and more preferably. 1-4. When Mw / Mn of the resin is outside the range of 1 to 6, developability and resolution tend to decrease.

  The resin (A) can be usually produced by radical polymerization using a radical polymerization initiator. For example, the presence of a chain transfer agent having a group represented by the general formula (1) (hereinafter referred to as “chain transfer agent (1)”) as a suitable monomer as described above giving the repeating units (2) and (3) A resin (A) as shown in the following general formula (4) can be obtained by polymerization with a radical polymerization initiator.

〔式（４）中、Ｒ’はラジカル重合開始剤由来の残基又は連鎖移動剤（１）由来の残基を示し、ＸはＳ−Ｒ¹で表される２価の基を示し、Ｒ¹は置換基を有することができる炭素数１〜２０の２価の炭化水素基を示す。〕

[In formula (4), R ′ represents a residue derived from a radical polymerization initiator or a residue derived from a chain transfer agent (1), X represents a divalent group represented by S—R ¹ , and R ¹ shows the C1-C20 bivalent hydrocarbon group which can have a substituent. ]

  Preferable chain transfer agent (1) includes a compound represented by the following general formula (5).

〔Ｒ¹は置換基を有することができる炭素数１〜２０の２価の炭化水素基を示す。〕

[R ¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. ]

  Preferable specific examples of the compound represented by the general formula (5) include compounds represented by the following formulas (5-1) to (5-8).

  Preferable radical initiators used in the polymerization method as described above include thermal polymerization initiators, redox polymerization initiators, photopolymerization initiators, and the like. Specific examples include polymerization initiators such as peroxides and azo compounds. More specifically, t-butyl hydroperoxide, t-butyl perbenzoate, benzoyl peroxide, 2,2′-azobis (2,4 -Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile (AIBN), 1,1'-azobis (cyclohexanecarbonitrile), dimethyl-2,2'-azobisisobutyrate (MAIB), etc. Can be mentioned.

  The molar ratio of the radical polymerization initiator to the chain transfer agent in such a polymerization method is preferably (1: 1) to (0.005: 1), more preferably (1: 1) to (0.1: 1). When the amount of the chain transfer agent is not less than the amount of the radical polymerization initiator, the Mw of the resin (A) can be controlled within a suitable range, and a suitable amount of the end group (1) is introduced into the resin (A). be able to.

  The amount of radical polymerization initiator added to the monomer is preferably 1 to 10 mol, more preferably 3 to 6 mol, per 100 mol of the monomer. When the addition amount is too small, a high molecular weight body is obtained, and when it is too large, it is difficult to control the molecular weight. The amount of chain transfer agent added to the monomer is preferably 1 to 20 mol, more preferably 3 to 10 mol, per 100 mol of monomer. If the amount added is too small, it will be difficult to control the ends, and if it is too large, it will be difficult to control the molecular weight.

  The polymerization operation can be synthesized by a usual method such as batch polymerization or dropping polymerization. As the polymerization solvent, an organic solvent capable of dissolving the monomer, the radical polymerization initiator, and the chain transfer agent is used. Examples of the organic solvent include ketone solvents, ether solvents, aprotic polar solvents, ester solvents, aromatic solvents, and linear or cyclic aliphatic solvents. Examples of the ketone solvent include methyl ethyl ketone and acetone. Examples of ether solvents include alkoxyalkyl ethers such as methoxymethyl ether, ethyl ether, tetrahydrofuran, and 1,4-dioxane. Examples of the aprotic polar solvent include dimethylformamide and dimethyl sulfoxide. Examples of ester solvents include alkyl acetates such as ethyl acetate and methyl acetate. Aromatic solvents include alkylaryl solvents such as toluene, xylene, and halogenated aromatic solvents such as chlorobenzene. Examples of the aliphatic solvent include hexane and cyclohexane.

  The polymerization temperature is 20 to 120 ° C, preferably 50 to 110 ° C, more preferably 60 to 100 ° C. Although polymerization may be performed even in a normal air atmosphere, polymerization in an inert gas atmosphere such as nitrogen or argon is preferable. The polymerization time is generally 0.5 to 144 hours, preferably 1 to 72 hours, more preferably 2 to 24 hours.

[(B) Radiation sensitive acid generator component]
The radiation-sensitive acid generator used in the present invention is a compound that generates an acid upon exposure, and a specific group present in the resin (A) is dissociated by the action of this acid, resulting in exposure of the resist film. The portion becomes readily soluble in an alkali developer, and a resist pattern can be formed.

  Examples of the acid generator include onium salt compounds and sulfonimide compounds.

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

  Moreover, as said sulfonimide compound, the compound represented by following General formula (6) can be mentioned, for example.

〔式（６）中、Ｑは２価の有機基を示し、Ｒ⁸は１価の有機基を示す。〕

[In Formula (6), Q represents a divalent organic group, and R ⁸ represents a monovalent organic group. ]

  In the general formula (6), as Q, for example, a methylene group, a linear or branched alkylene group having 2 to 20 carbon atoms, an aralkylene group having 7 to 20 carbon atoms, a difluoromethylene group, or a carbon number 2 to 20 A linear or branched perfluoroalkylene group, a cyclohexylene group, a phenylene group, a divalent group having a norbornane skeleton, and an aryl group having 6 or more carbon atoms or an alkoxy group having 1 or more carbon atoms in these groups. Examples of the substituent include a bonded group.

Examples of R ⁸ include a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched perfluoroalkyl group having 1 to 10 carbon atoms, and a perfluoroalkyl group having 3 to 10 carbon atoms. Examples thereof include a fluorocycloalkyl group, a monovalent bicyclo ring-containing hydrocarbon group having 7 to 15 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

  Other acid generators are preferably one or more selected from the group of onium salt compounds and sulfonimide compounds.

  Other particularly preferred acid generators include bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl). ) Iodonium p-toluenesulfonate, bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylphenyl) iodonium 2-trifluoromethylbenzenesulfonate, bis (4-t-butylphenyl) iodonium 4-trifluoromethylbenzenesulfonate, bis (4-t-butylphenyl) iodonium 2,4-difluorobenzenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nona Fluoro-n-butanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium 2-trifluoromethylbenzenesulfonate, triphenylsulfonium 4-trifluorobenzenesulfonate, triphenylsulfonium 2,4 -Difluoromethylbenzenesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n -Butanesulfonate, N- (trifluoromethanesulfonyloxy) succinimide, N- (trifluoromethanesulfonyloxy) bicyclo [2.2. ] Hept-5-ene-2,3-dicarboximide, N- (10-camphorsulfonyloxy) succinimide, N- (10-camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2 , 3-dicarboximide, N-{(5-methyl-5-carboxymethanebicyclo [2.2.1] hept-2-yl) sulfonyloxy} succinimide.

  The radiation sensitive acid generators as described above can be used alone or in admixture of two or more. The amount of the radiation-sensitive acid generator used is usually 0.1 to 10 parts by mass, preferably 0.5 to 100 parts by mass of the resin (A) from the viewpoint of ensuring the sensitivity and developability as a resist. -7 parts by mass. If the amount of the radiation-sensitive acid generator used is less than 0.1 parts by mass, the sensitivity and developability decrease. If it exceeds 10 parts by mass, the radiation transmittance decreases and a rectangular resist pattern can be obtained. It tends to be difficult.

[(C) Acid diffusion controller component]
By adding an acid diffusion control agent that controls the diffusion of the acid generated from the radiation-sensitive acid generator, the radiation-sensitive resin composition can more effectively improve the verticality of the side wall of the resist pattern. . In addition, by adding such an acid diffusion controller, the storage stability of the radiation-sensitive resin composition is improved, the resolution as a resist is further improved, and the holding time from exposure to development processing ( The change in the line width of the resist pattern due to the variation in PED) can be suppressed, and as a result, a radiation-sensitive resin composition having extremely excellent process stability can be obtained.

  As such an acid diffusion controller, a nitrogen-containing organic compound whose basicity is not changed by exposure or heat treatment in the resist pattern forming step is preferable. Examples of the nitrogen-containing organic compound include a compound represented by the following general formula (7) (hereinafter referred to as “nitrogen-containing compound (I)”), a diamino compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (I)”). And "nitrogen-containing compound (II)"), amide group-containing compounds, nitrogen-containing heterocyclic compounds, and the like.

〔式（７）中、各Ｒ⁹は相互に独立に水素原子、アルキル基、アリール基又はアラルキル基を示し、これらの各基は置換されていてもよい。〕

[In the formula (7), each R ⁹ independently represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and each of these groups may be substituted. ]

In the general formula (7), examples of the optionally substituted alkyl group represented by R ⁹ include those having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, specifically, methyl group, ethyl group, n- Propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, texyl group, n-heptyl group, An n-octyl group, n-ethylhexyl group, n-nonyl group, n-decyl group, etc. can be mentioned.

Examples of the optionally substituted aryl group represented by R ⁹ include those having 6 to 12 carbon atoms, specifically, phenyl group, tolyl group, xylyl group, cumenyl group, 1-naphthyl group and the like. be able to.

Examples of the optionally substituted aralkyl group represented by R ⁹ include those having 7 to 19 carbon atoms, preferably 7 to 13 carbon atoms, specifically, benzyl group, α-methylbenzyl group, phenethyl group, 1 -A naphthylmethyl group etc. can be mentioned.

  Specific examples of the nitrogen-containing compound (I) include, for example, monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; di-n-butylamine, di- -Dialkylamines such as n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine; triethylamine, tri-n- Such as propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, etc. Trialkylamines; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline Aromatic amines such as 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine and 1-naphthylamine; alkanolamines such as ethanolamine, diethanolamine and triethanolamine .

  Specific examples of the nitrogen-containing compound (II) include, for example, ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, N, N, N ′, N′— Examples thereof include tetrakis (2-hydroxyethyl) ethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, and the like.

  Specific examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methyl. Pyrrolidone etc. can be mentioned.

  Specific examples of the nitrogen-containing heterocyclic compound include, for example, imidazole, benzimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, 4-phenylimidazole, 4- Imidazoles such as methyl-2-phenylimidazole and 2-phenylbenzimidazole; pyridines such as pyridine, quinoline, 8-oxyquinoline and acridine, as well as pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine and piperidine be able to.

  Furthermore, a compound having an acid dissociable group can also be used as the nitrogen-containing organic compound. Examples of the nitrogen-containing organic compound having an acid-dissociable group include N- (t-butoxycarbonyl) piperidine, N- (t-butoxycarbonyl) imidazole, N- (t-butoxycarbonyl) benzimidazole, N- (t -Butoxycarbonyl) 2-phenylbenzimidazole, N- (t-butoxycarbonyl) dioctylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine Etc.

  Of these nitrogen-containing organic compounds, nitrogen-containing compounds (I), nitrogen-containing compounds (II), nitrogen-containing heterocyclic compounds and the like are preferable. These acid diffusion control agents can be used alone or in admixture of two or more.

  The compounding amount of the acid diffusion controller is preferably 15 parts by mass or less, more preferably 0.001 to 10 parts by mass, particularly preferably 0.005 to 100 parts by mass of the (B) acid dissociable group-containing resin. 5 parts by mass. In this case, by setting the compounding amount of the acid diffusion controller to 0.001 part by mass or more, it is possible to suppress a decrease in pattern shape and dimensional fidelity as a resist depending on process conditions, and to 15 parts by mass or less. Thus, the sensitivity as a resist and the developability of the exposed portion can be improved.

[Other additives]
-Dissolution control agent-
The radiation-sensitive resin composition can be blended with a dissolution control agent having a property of increasing the solubility in an alkali developer by the action of an acid. As such a dissolution control agent, for example, a compound having an acidic functional group such as a phenolic hydroxyl group, a carboxyl group, or a sulfonic acid group, or a hydrogen atom of the acidic functional group in the compound is substituted with an acid dissociable group A compound etc. can be mentioned. The said dissolution control agent can be used individually or in mixture of 2 or more types. The compounding quantity of a dissolution control agent is 10 mass parts or less normally with respect to 100 mass parts of all the resin components in a radiation sensitive resin composition, Preferably it is 5 mass parts or less.

-Surfactant-
In the radiation sensitive resin composition, a surfactant exhibiting an action of improving the coating property, striation, developability and the like of the radiation sensitive resin composition may be blended. As such a surfactant, any of anionic, cationic, nonionic or amphoteric surfactants can be used, but nonionic surfactants are preferred. Nonionic surfactants include, for example, polyoxyethylene higher alkyl ethers, polyoxyethylene higher alkyl phenyl ethers, polyethylene glycol higher fatty acid diesters, and “KP” (manufactured by Shin-Etsu Chemical Co., Ltd.). ), "Polyflow" (manufactured by Kyoeisha Yushi Chemical Industry Co., Ltd.), "F Top" (manufactured by Tochem Products), "Megafuck" (manufactured by Dainippon Ink and Chemicals), "Florard" (manufactured by Sumitomo 3M), "Asahi Guard" And each series such as “Surflon” (manufactured by Asahi Glass). Surfactant can be used individually or in mixture of 2 or more types. The compounding amount of the surfactant is usually 2 parts by mass or less, preferably 1.5 parts by mass or less as an active ingredient of the surfactant with respect to 100 parts by mass of the total resin components in the radiation-sensitive resin composition. .

-Sensitizer-
The radiation-sensitive resin composition has a function of absorbing radiation energy and transmitting the energy to the radiation-sensitive acid generator, thereby increasing the amount of acid generated. A sensitizer capable of improving the apparent sensitivity can be blended. Examples of such sensitizers include acetophenones, benzophenones, naphthalene, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like. These sensitizers can be used alone or in admixture of two or more. The compounding quantity of a sensitizer is 50 mass parts or less normally with respect to 100 mass parts of all the resin components in a radiation sensitive resin composition, Preferably it is 30 mass parts or less.

  Furthermore, in the radiation sensitive resin composition, additives other than those described above, for example, dyes, pigments, adhesion assistants, antihalation agents, storage stabilizers, as necessary, as long as the effects of the present invention are not impaired. , An antifoaming agent, a shape improving agent, and the like, specifically, 4-hydroxy-4′-methylchalcone and the like can also be blended. In this case, by blending a dye or pigment, the latent image in the exposed area can be visualized, and the influence of halation during exposure can be mitigated, and the adhesion to the substrate can be improved by blending an adhesion assistant. be able to.

Preparation of composition solution The radiation-sensitive resin composition is usually obtained by dissolving each component in a solvent to form a uniform solution at the time of use, and then filtering with a filter having a pore size of about 0.2 μm, if necessary. Prepared as a composition solution.

  Examples of the solvent used here include ethers, esters, ether esters, ketones, ketone esters, amides, amide esters, lactams, lactones, (halogenated) hydrocarbons, and the like. More specifically, ethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, propylene glycol monoalkyl ethers, propylene glycol dialkyl ethers, ethylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ether acetates , Acetate esters, hydroxy acetate esters, lactate esters, alkoxyacetate esters, (non) cyclic ketones, acetoacetate esters, pyruvate esters, propionate esters N, N-dialkylformamides, N, N-dialkylacetamides, N-alkylpyrrolidones, γ-lactones, (halogenated) aliphatic hydrocarbons, (halogenated) aromatic hydrocarbons, etc. Can be mentioned.

  Specific examples of the solvent include 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, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, isopropenyl acetate, isopropenyl pro Pionate, G Ene, xylene, methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, 4-heptanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy- Methyl 3-methylbutyrate, methyl lactate, ethyl lactate, n-propyl lactate, i-propyl lactate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion Methyl acid, 3- Tokishipuropion ethyl, N- methylpyrrolidone, N, N- dimethylformamide, N, may be mentioned N- dimethylacetamide.

  Among these solvents, propylene glycol monoalkyl ether acetates, 2-heptanone, lactic acid esters, 2-hydroxypropionic acid esters, 3-alkoxypropionic acid esters, etc. have good in-plane uniformity during coating. Is preferable in that. A solvent can be used individually or in mixture of 2 or more types.

  If necessary, other solvents such as benzyl ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1 Use high-boiling solvents such as octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, ethylene glycol monophenyl ether acetate, etc. be able to. These other solvents can be used alone or in admixture of two or more. The proportion of other solvents used is usually 50% by mass or less, preferably 30% by mass or less, based on the total solvent.

  The total amount of the solvent used is such that the total solid concentration of the solution is usually 5 to 50% by mass, preferably 10 to 50% by mass, more preferably 10 to 40% by mass, and particularly preferably 10 to 30% by mass. The amount is 10 to 25% by mass. By setting the total solid content concentration of the solution within this range, it is preferable in that the in-film uniformity during coating is good.

Formation of Resist Pattern The resist pattern can be formed from the radiation sensitive resin composition by the following method. By applying the composition solution prepared as described above onto a substrate such as a silicon wafer or a wafer coated with aluminum by an appropriate application means such as spin coating, cast coating or roll coating. Then, a resist film is formed. Thereafter, a heat treatment (hereinafter referred to as “PB”) is performed in advance in some cases, and then the resist film is exposed through a predetermined mask pattern.

The radiation that can be used in the exposure includes (A) an emission line spectrum of a mercury lamp (wavelength 254 nm), a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength), depending on the type of acid generator used. 193 nm), far ultraviolet rays such as F ₂ excimer laser (wavelength 157 nm), EUV (wavelength 13 nm, etc.), X-rays such as synchrotron radiation, charged particle beams such as electron beams, etc., preferably far ultraviolet rays And a charged particle beam, particularly preferably a KrF excimer laser, an ArF excimer laser, an F ₂ excimer laser, and an electron beam.

  In addition, exposure conditions such as radiation dose are appropriately selected according to the composition of the radiation-sensitive resin composition, the type of additive, and the like. In forming a resist pattern, it is preferable to perform a heat treatment after exposure (hereinafter, this heat treatment is referred to as “PEB”) from the viewpoint of improving the apparent sensitivity of the resist. The heating conditions for PEB vary depending on the composition of the radiation-sensitive resin composition, the type of additive, and the like, but are usually 30 to 200 ° C, preferably 50 to 150 ° C.

  Then, a predetermined resist pattern is formed by developing the exposed resist film with an alkaline developer. Examples of the alkali developer include alkali metal hydroxides, aqueous ammonia, alkylamines, alkanolamines, heterocyclic amines, tetraalkylammonium hydroxides, choline, 1,8-diazabicyclo [5.4. 0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene and the like, an alkaline aqueous solution in which one or more alkaline compounds are dissolved is used. A particularly preferred alkaline developer is a tetraalkylammonium developer. It is an aqueous solution of hydroxides.

  The concentration of the alkaline aqueous solution is preferably 10% by mass or less, more preferably 1 to 10% by mass, and particularly preferably 2 to 5% by mass. In this case, by setting the concentration of the alkaline aqueous solution to 10% by mass or less, dissolution of the non-exposed portion in the developer can be suppressed. Further, it is preferable to add an appropriate amount of a surfactant or the like to the developer composed of the alkaline aqueous solution, whereby the wettability of the developer with respect to the resist can be enhanced. In addition, after developing with the developing solution which consists of the said alkaline aqueous solution, generally it wash | cleans with water and dries.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples of the present invention. However, the present invention is not limited to these examples.

  Mw is a GPC column (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, and the monodisperse polystyrene is analyzed under the analysis conditions of a flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. It was measured by gel permeation chromatography (GPC) as a standard.

[Synthesis Example 1]
The following compound (8-1) 53.92 g (50 mol%), compound (8-2) 10.69 g (10 mol%), compound (8-3) 35.38 g (40 mol%) A monomer solution prepared by dissolving 2.87 g of dimethyl 2,2′-azobis (2-methylpropionate) and 3.5 g of 3-mercaptopropionic acid was prepared by dissolving in 187 g of butanone, and 100 g of 2-butanone was prepared. The charged 1000 ml three-necked flask was purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the three-necked flask was heated to 80 ° C. while stirring, and the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration.

The filtered white powder was washed twice as a slurry with 400 g of methanol, separated after drying, dried at 50 ° C. for 17 hours, and a white powder having —S—CH ₂ —CH ₂ —COOH groups at the ends. Resin was obtained (75 g, 75% yield). As a result of IR measurement, absorption at 3300 cm ⁻¹ was confirmed. This resin has Mw of 7400, and as a result of ¹³ C-NMR analysis, the content of each repeating unit formed from compound (8-1), compound (8-2), and compound (8-3) is 52. The copolymer resin was 0: 8.6: 39.4 (mol%). This resin is referred to as “resin (A-1)”.

[Synthesis Example 2]
The following compound (9-1) 24.31 g (50 mol%), compound (9-2) 7.75 g (15 mol%), compound (9-3) 17.94 g (35 mol%) A monomer solution was prepared by adding 1.01 g of dimethyl 2,2′-azobis (2-methylpropionate) and 1.75 g of 3-mercaptopropionic acid to 150 g of butanone, and 100 g of 2-butanone was added. A 1000 ml three-necked flask was purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the three-necked flask was heated to 80 ° C. while stirring, and the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration.

The filtered white powder was washed twice as a slurry with 400 g of methanol, separated after drying, dried at 50 ° C. for 17 hours, and a white powder having —S—CH ₂ —CH ₂ —COOH groups at the ends. Resin was obtained (35 g, 75% yield). As a result of IR measurement, absorption at 3300 cm ⁻¹ was confirmed. This resin has Mw of 7400, and as a result of ¹³ C-NMR analysis, the content of each repeating unit formed from the compound (9-1), the compound (9-2) and the compound (9-3) is 51. 5, 13.6, 34.9 (mol%) copolymer resin. This resin is referred to as “resin (A-2)”.

[Synthesis Example 3]
The following compound (10-1) 24.62 g (50 mol%), compound (10-2) 5.77 g (37 mol%), compound (10-3) 19.61 g (13 mol%) A monomer solution prepared by dissolving 1.04 g of dimethyl 2,2′-azobis (2-methylpropionate) and 1.75 g of 3-mercaptopropionic acid was prepared by dissolving in 150 g of butanone, and 100 g of 2-butanone was prepared. The 1000 ml three-necked flask charged with was purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the three-necked flask was heated to 80 ° C. while stirring, and the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration.

The filtered white powder was washed twice as a slurry with 2000 g of isopropyl alcohol, filtered, dried at 60 ° C. for 17 hours, and has a —S—CH ₂ —CH ₂ —COOH group at the terminal. A white powdery resin was obtained (85 g, 85% yield). As a result of IR measurement, absorption at 3300 cm ⁻¹ was confirmed. This resin has Mw of 6200, and as a result of ¹³ C-NMR analysis, the content of each repeating unit formed from the compound (10-1), the compound (10-2), and the compound (10-3) is 54. 5: 31.9: 13.5 (mol%) copolymer resin. This resin is referred to as “resin (A-3)”.

[Comparative Synthesis Example 1]
The above compound (8-1) 53.92 g (50 mol%), compound (8-2) 10.69 g (10 mol%), compound (8-3) 35.38 g (40 mol%) was added to 2-butanone 187 g. A monomer solution containing 2.24 g of dimethyl 2,2′-azobis (2-methylpropionate) was prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. did. After purging with nitrogen, the inside of the three-necked flask was heated to 80 ° C. while stirring, and the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration.

The filtered white powder was washed twice as a slurry with 400 g of methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (72 g, yield 72%). . This polymer has Mw of 8500, and as a result of ¹³ C-NMR analysis, the content of each repeating unit formed from the compound (8-1), the compound (8-2) and the compound (8-3) is 52. .2: 8.0: 39.8 (mol%) copolymer. This polymer is referred to as “polymer (A′-1)”.

[Comparative Synthesis Example 2]
The above compound (9-1) 24.31 g (50 mol%), the compound (9-2) 7.75 g (15 mol%), the compound (9-3) 17.94 g (35 mol%) were added to 2-butanone 150 g. Further, a 1.01 g monomer solution of dimethyl 2,2′-azobis (2-methylpropionate) was prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the three-necked flask was heated to 80 ° C. while stirring, and the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration.

The filtered white powder was washed twice with 400 g of methanol as a slurry, washed, separated, and dried at 50 ° C. for 17 hours to obtain a white powder resin (38 g, yield 88%). This resin has an Mw of 8200, and as a result of ¹³ C-NMR analysis, the content of each repeating unit formed from the compound (9-1), the compound (9-2), and the compound (9-3) is 52. 1, 13.6, 34.3 (mol%) copolymer resin. This resin is referred to as “resin (A′-2)”.

[Comparative Synthesis Example 3]
The above compound (10-1) 24.62 g (50 mol%), the compound (10-2) 5.77 g (37 mol%), the compound (10-3) 19.61 g (13 mol%) and 2-butanone 150 g And a monomer solution charged with 1.04 g of dimethyl 2,2′-azobis (2-methylpropionate) was prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone was charged with nitrogen for 30 minutes. Purged. After purging with nitrogen, the inside of the three-necked flask was heated to 80 ° C. while stirring, and the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration.

The filtered white powder was washed twice as a slurry with 2000 g of isopropyl alcohol, separated after drying, and dried at 60 ° C. for 17 hours to obtain a white powder resin (85 g, yield 85%). This resin has Mw of 6200, and as a result of ¹³ C-NMR analysis, the content of each repeating unit formed from the compound (10-1), the compound (10-2), and the compound (10-3) is 54. 1: 31.9: 13.9 (mol%) copolymer resin. This resin is referred to as “resin (A′-3)”.

[Comparative Synthesis Example 4]
49.24 g (100 mol%) of the above compound (10-1) was dissolved in 150 g of 2-butanone, and further 1.04 g of dimethyl 2,2′-azobis (2-methylpropionate), 3-mercaptopropionic acid 1 A monomer solution charged with .75 g was prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the three-necked flask was heated to 80 ° C. while stirring, and the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration.

The filtered white powder was washed twice as a slurry with 2000 g of isopropyl alcohol, separated after drying, dried at 60 ° C. for 17 hours, and white having —S—CH ₂ —CH ₂ —COOH groups at the ends. A powdery resin was obtained (85 g, 85% yield). As a result of IR measurement, absorption at 3300 cm ⁻¹ was confirmed. This resin has Mw of 6500, and this resin is referred to as resin (A′-4).

[Examples 1 and 2, Reference Example 1 and Comparative Examples 1 to 4]
After the resins obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Examples 1 to 4, the acid generator shown below, and other components were blended in the ratios shown in Table 1 to obtain a uniform solution, the pore size was 0. Each of the composition solutions of Examples 1 and 2, Reference Example 1 and Comparative Examples 1 to 4 was prepared by filtration through a 2 μm membrane filter. The obtained radiation-sensitive resin composition solution was exposed under the conditions shown in Table 2 and subjected to various evaluations. The evaluation results are shown in Table 3. Here, the part is based on mass unless otherwise specified.

[Acid generator (B)]
(B-1): Triphenylsulfonium / nonafluoro-n-butanesulfonate [Acid Diffusion Control Agent (C)]
(C-1): 2-Phenylbenzimidazole [Solvent (D)]
(D-1): Propylene glycol methyl ether acetate (D-2): Cyclohexanone

[Evaluation methods]
(1) Sensitivity:
Using a silicon wafer (ARC29) having an ARC29 (made by Brewer Science) film having a film thickness of 770 angstroms formed on the wafer surface, each composition solution was applied onto the substrate by spin coating, and on a hot plate, Table 2 The resist film having a film thickness of 0.25 μm formed by performing PB under the conditions shown in FIG. 6 was exposed through a mask pattern using a Nikon ArF excimer laser exposure apparatus (numerical aperture 0.75). Thereafter, PEB was performed under the conditions shown in Table 2, and then developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 25 ° C for 60 seconds, washed with water, and dried to form a positive resist pattern. . At this time, an exposure amount for forming a line-and-space pattern (1L1S) having a line width of 0.11 μm in a one-to-one line width was defined as an optimum exposure amount, and this optimum exposure amount was defined as sensitivity.

(2) Resolution:
The dimension of the smallest line and space pattern that can be resolved at the optimum exposure dose was taken as the resolution.

(3) Pattern profile:
The lower side dimension L1 and the upper side dimension L2 of the rectangular cross section of the line-and-space pattern (1L1S) having a line width of 0.16 μm were measured with a scanning electron microscope, and 0.85 ≦ L2 / L1 ≦ 1 was satisfied. In addition, when the pattern profile has no bottom, the pattern profile is determined to be “good”.

(4) Line edge roughness (LER):
When observing the 110 nm 1L / 1S pattern resolved at the optimum 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.

As shown in Table 3, in Examples 1 and 2 , radiation sensitive resin compositions excellent in resolution, pattern profile, and line edge roughness (LER) characteristics as basic resist performances were obtained.

  Since the radiation sensitive resin composition of the present invention is excellent in line edge roughness (LER) characteristics, it is extremely useful as a chemically amplified resist for semiconductor device production, which is expected to be further refined from now on.

Claims (2)

(A) A resin having a group represented by the following general formula (1) at at least one end of a molecular chain, hardly soluble or insoluble in alkali, and easily soluble in alkali by the action of an acid. formula repeating unit represented by (2), and the following general formula (3) a resin having a repeating unit represented by, and (B) a radiation-sensitive acid generator to that radiation sensitive resin composition containing a.

In [Equation (1), X represents a divalent group represented by S-R ^1, R ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. ]

[In formula (2), ^{R 2} represents a hydrogen atom or a methyl ^group, R 3, ^{R 4} and ^{R 5} are satisfying group of the following (i).
(I) Any two of R ³ , R ⁴ and R ⁵ are bonded to each other to form a cyclopentyl group, a cyclohexyl group, or a derivative thereof including the carbon atoms to which each is bonded, and the remaining 1 One is a straight-chain or branched alkyl group having a carbon number of 1-4. ]

In [formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, 1 to 4 carbon atoms linear Or a branched alkoxy group is represented. ]   (C) The radiation sensitive resin composition of Claim 1 containing an acid diffusion control agent.