JP2007246588A - Chain transfer agent for living radical polymerization and alicyclic hydrocarbon group-containing polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer prepared by living radical polymerization and useful as a resist material, excellent in light permeability in the wavelength of an exposure light source through film thickness in the practical level, even when terminal groups derived from RAFT agent used in the living radical polymerization remain, and well improved in line edge roughness owing to small polydispersity Mw/Mn; and a chain transfer agent (RAFT agent) preferably used for producing the polymer. <P>SOLUTION: The chain transfer agent for living radical polymerization has a structure expressed by general formula (1). The alicyclic hydrocarbon group-containing polymer is prepared by carrying out the living radical polymerization using the chain transfer agent, has acid dissociating groups and insoluble or hardly soluble in alkalis. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chain transfer agent for living radical polymerization and an alicyclic hydrocarbon group-containing polymer. More specifically, the present invention relates to a chain transfer agent for living radical polymerization that can be used in producing a resist resin component useful for microfabrication technology using far ultraviolet rays and vacuum ultraviolet rays such as KrF excimer laser or ArF excimer laser, And an alicyclic hydrocarbon group-containing polymer that can be produced using the chain transfer agent for living radical polymerization.

  Along with the miniaturization of semiconductors, an optical lithography process using an ArF excimer laser (wavelength 193 nm) light source is about to be used in earnest for mass production of miniaturized semiconductors. In addition, with the shortening of the exposure light wavelength, the space between the lower surface of the projection optical system and the wafer surface is filled with a liquid such as water or an organic solvent, and the wavelength of the exposure light in the liquid is 1 / n times that in air ( There has been proposed immersion lithography that improves the resolution by utilizing the fact that n is the refractive index of a liquid, which is usually about 1.2 to 1.6 (see, for example, Patent Document 1).

  With regard to the resist resin, development and improvement of the resist resin for realizing a better pattern shape with higher resolution for use in the lithography process has been vigorously advanced. As a resist resin used in such a lithography process, a chemically amplified photosensitive composition utilizing a chemical amplification effect by a resin component having an acid-dissociable functional group and an acid generator that is a component that generates an acid by light irradiation. Many things have been proposed so far. The resin component used here must have high transparency with respect to the exposure light source wavelength. In lithography using an ArF excimer laser (wavelength 193 nm), an acrylic resin or cycloolefin resin containing an alicyclic structure is used. It is used.

  Many resist resins are copolymers composed of a plurality of monomer units. Various design means are conceivable for the molecular design of the copolymer to obtain a good pattern shape with high resolution. One of them is to control the molecular weight and molecular weight distribution (polydispersity) of the copolymer. Such control is expected to improve the line edge roughness of the side wall surface of the resist pattern after exposure and development, which is a big problem in pattern miniaturization. If the copolymer molecular weight and molecular weight distribution (polydispersity) vary, line edge roughness that causes the resist pattern side wall surface to become uneven is likely to occur, and substrate processing dimensional accuracy deteriorates, which is large in performing fine processing. It becomes a problem.

  The above copolymer can be obtained by industrially useful radical polymerization, but living radical polymerization is preferably used for obtaining a polymer having a clear structure by radical polymerization. Examples of the living radical polymerization include i) NMP (nitroxide-mediated polymerization) method, ii) ATRP (atom-transfer radical polymerization) method, and iii) RAFT (reversible addition-fragmentation fragmentation method).

  The NMP method is generally suitable for the synthesis of styrenic polymers, but is not suitable for the synthesis of acrylic polymers. The ATRP method is generally suitable for the synthesis of an acrylic polymer. However, since a transition metal catalyst is used as a catalyst during polymerization, the ATRP method is not suitable for the synthesis of a resist material from the viewpoint of metal contamination of the product.

  The RAFT method is reported to be suitable for polymerization of acrylic monomers and methacrylic monomers using an organic sulfur compound (hereinafter sometimes referred to as a RAFT agent) such as a dithiocarboxylic acid ester serving as a chain transfer agent as a catalyst. (For example, refer nonpatent literature 1).

  In the RAFT method, the residue of the RAFT agent remains as a terminal group as a dormant species at the polymerization end (in the text, unless otherwise specified, the polymerization end is the polymer growth end side only). The remaining proportion of the end groups is not particularly limited because it varies depending on the polymerization conditions, but is generally 50 to 100%. Here, many of the RAFT agents used in the RAFT method contain an aromatic ring. Therefore, the residue of the RAFT agent remaining as a terminal group has a strong absorption band in the ultraviolet region derived from the aromatic ring. For this reason, the polymer in which the residue of the RAFT agent remains as a terminal group is not sufficient for improving the performance as a resist resin even though it is effective for controlling the polymerization because of the inhibition of ultraviolet light transmission in a specific wavelength region. Absent.

In order to solve the above problem, the residue of the RAFT agent remaining as a terminal group is brought into contact with a radical source such as 2,2′-azobisisobutyronitrile (hereinafter referred to as AIBN) to thereby obtain 1-cyano. A method for conversion to the -1-methylethyl terminal has been reported (for example, see Non-Patent Document 2). In addition, a method for converting a polymer end group using a chain transfer agent such as alkylthiol and a radical source such as AIBN has also been reported (see, for example, Patent Document 2). However, these methods increase the number of steps and become complicated, and are not efficient manufacturing methods.
JP-A-10-303114 JP 2006-2096 A Macromolecules 1998, 31, 5559-5562. Journal of Photopolymer Science and Technology 2005, 18, 389-392.

  An object of the present invention is a polymer obtained by living radical polymerization, which is useful as a resist material, and an exposure light source with a film thickness at a practical level even if a terminal group derived from the RAFT agent used in living radical polymerization remains. It is preferable for providing a polymer having excellent light transmittance at a wavelength and having a good improvement in line edge roughness due to a low polydispersity Mw / Mn, and for producing such a polymer. It is to provide a chain transfer agent (RAFT agent) that can be used.

（一般式（１）中、Ｒ_１は飽和炭化水素基、Ｒ_２はシアノ基を有する飽和炭化水素基を表す。） The chain transfer agent for living radical polymerization of the present invention has a structure represented by the general formula (1).

(In general formula (1), R ₁ represents a saturated hydrocarbon group, and R ₂ represents a saturated hydrocarbon group having a cyano group.)

（一般式（２）中、Ｒ_１は飽和炭化水素基を表す。）

（一般式（３）中、Ｒ_３、Ｒ_４、Ｒ_５は水素原子または飽和炭化水素基を表す。） In a preferred embodiment, the chain transfer agent for living radical polymerization of the present invention reacts a compound having a structure represented by the general formula (2) with a compound having a structure represented by the general formula (3). can get.

(In general formula (2), R ₁ represents a saturated hydrocarbon group.)

(In general formula (3), R ₃ , R ₄ , and R ₅ represent a hydrogen atom or a saturated hydrocarbon group.)

  In a preferred embodiment, the compound having the structure represented by the general formula (3) is (meth) acrylonitrile.

  According to another aspect of the present invention, an alicyclic hydrocarbon group-containing polymer is provided. The alicyclic hydrocarbon group-containing polymer of the present invention is a polymer obtained by conducting living radical polymerization using the chain transfer agent of the present invention, and has an acid-dissociable group and is insoluble in alkali or alkali. Slightly soluble.

  In a preferred embodiment, the alicyclic hydrocarbon group-containing polymer of the present invention is obtained by performing living radical polymerization using at least one (meth) acrylic acid ester as a raw material.

  In a preferred embodiment, the (meth) acrylic acid ester contains an alicyclic hydrocarbon group as an ester group.

  In a preferred embodiment, the alicyclic hydrocarbon group-containing polymer of the present invention has a polydispersity Mw / Mn of 1.6 or less, and a transmittance of ultraviolet light having a wavelength of 193 nm per 200 nm thickness is 70% or more. It is.

  In a preferred embodiment, the alicyclic hydrocarbon group-containing polymer of the present invention is a resist resin.

  According to the present invention, it is a polymer obtained by living radical polymerization that is useful as a resist material, and an exposure light source with a film thickness at a practical level even if a terminal group derived from the RAFT agent used in living radical polymerization remains. It is possible to provide a polymer that has excellent light transmittance at a wavelength and that has excellent line edge roughness due to low polydispersity Mw / Mn. Moreover, the chain transfer agent which can be preferably used in order to manufacture such a polymer can be provided.

  Such an effect can be expressed by using a dithiocarboxylic acid ester having a specific structure having a saturated hydrocarbon group having a cyano group as an ester group as a chain transfer agent used in living radical polymerization. Become. Moreover, it is expressed by conducting living radical polymerization using at least one (meth) acrylic acid ester, preferably one or more of (meth) acrylic acid ester containing an alicyclic hydrocarbon group as an ester group. Is possible.

  Hereinafter, although preferable embodiment of this invention is described, this invention is not limited to these embodiment.

[Chain transfer agent for living radical polymerization]
The chain transfer agent for living radical polymerization of the present invention has a structure represented by the general formula (1).

In the general formula (1), R ₁ is a saturated hydrocarbon group, and any appropriate saturated hydrocarbon group can be adopted. Preferably it is a C1-C20, More preferably, it is a C1-C10, More preferably, it is a C1-C5, Most preferably, it is a C1-C3 saturated hydrocarbon group. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and a cyclohexyl group.

In general formula (1), R ₂ is a saturated hydrocarbon group having a cyano group, and any appropriate saturated hydrocarbon group having a cyano group can be adopted. Preferably it is a C1-C20, More preferably, it is a C1-C10, More preferably, it is a C1-C7, Most preferably, it is a C1-C4 saturated hydrocarbon group. Specifically, for example, cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group, 1-cyano-1-n-propyl group, 2-cyano-1-n-propyl group, 3-cyano-1-n- A propyl group, 1-cyano-2-n-propyl group, 2-cyano-2-n-propyl group and the like can be mentioned.

The chain transfer agent for living radical polymerization of the present invention can be produced by any appropriate method. Preferably, the chain transfer agent for living radical polymerization of the present invention is obtained by reacting a compound having a structure represented by the general formula (2) with a compound having a structure represented by the general formula (3).

In General Formula (2), R ₁ represents a saturated hydrocarbon group, and is the same group as R ₁ in General Formula (1).

In the general formula (3), R ₃ , R ₄ and R ₅ are hydrogen atoms or saturated hydrocarbon groups, and any appropriate hydrogen atom or saturated hydrocarbon group can be adopted. At least two of R ₃ , R ₄ , and R ₅ may be the same, or all three may be different. In the case of a saturated hydrocarbon group, it is preferably a saturated hydrocarbon group having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

As the compound having the structure represented by the general formula (3), any appropriate compound can be adopted as long as R ₃ , R ₄ , and R ₅ are a hydrogen atom or a saturated hydrocarbon group, but the reactivity is good. (Meth) acrylonitrile is preferred because of its low cost, ease of handling, and availability.

  As a specific method for producing the chain transfer agent for living radical polymerization of the present invention by reacting the compound having the structure represented by the general formula (2) with the compound having the structure represented by the general formula (3) For example, it is preferable to react a compound having a structure represented by the general formula (2) with a compound having a structure represented by the general formula (3) in a solvent.

  The ratio of the compound having the structure represented by the general formula (2) and the compound having the structure represented by the general formula (3) in the above reaction is the compound 1 having the structure represented by the general formula (2). The compound having a structure represented by the general formula (3) is preferably 0.5 to 4.0 equivalents, more preferably 1.0 to 2.5 equivalents with respect to equivalents.

  Any appropriate solvent can be adopted as the solvent that can be used in the above reaction. Examples thereof include halogenated carbon solvents such as dichloromethane, 1,2-dichloroethane, chloroform, and carbon tetrachloride; hydrocarbon solvents such as hexane, cyclohexane, decalin, benzene, toluene, and xylene. Preferably, they are benzene and toluene.

  The amount of the solvent that can be used in the above reaction is preferably 2 to 50 times by weight, more preferably 3 to 10 times by weight with respect to the compound having a structure represented by the general formula (2).

  The reaction temperature of the above reaction is preferably 20 to 120 ° C, more preferably 40 to 100 ° C.

  The reaction time for the above reaction varies depending on the reagent amount and the reaction temperature, but is preferably 2 to 48 hours, and more preferably 12 to 24 hours.

  In the above reaction, any appropriate processing operation such as concentration operation, purification operation, and drying operation may be performed according to a conventional method.

(Aricyclic hydrocarbon group-containing polymer)
The alicyclic hydrocarbon group-containing polymer of the present invention is a polymer obtained by performing living radical polymerization using the chain transfer agent for living radical polymerization of the present invention, and has an acid-dissociable group, It is insoluble in alkali or hardly soluble in alkali.

  Here, the “alicyclic hydrocarbon group” in the present invention refers to a hydrocarbon group having a cyclic group having no aromaticity, and includes those having a hetero atom such as an oxygen atom or a nitrogen atom.

  The alicyclic hydrocarbon group-containing polymer of the present invention may be a homopolymer (homopolymer) or a copolymer (copolymer). In the case of a copolymer, the arrangement state of the corresponding monomer is not particularly limited, and may be, for example, a random copolymer or a block copolymer.

  The acid dissociable group possessed by the alicyclic hydrocarbon group-containing polymer of the present invention is an alkali-insoluble or hardly alkali-soluble group, and is a group that becomes readily alkali-soluble by the action of an acid. Specifically, for example, an ester group in which a tertiary or quaternary carbon atom is bonded to an oxygen atom (O—) of an O═C—O— group is preferable.

  As the structural unit (repeating unit derived from the structure of the raw material monomer) possessed by the alicyclic hydrocarbon group-containing polymer of the present invention, any suitable structural unit derived from the structure of the raw material monomer can be adopted.

  Any appropriate monomer can be adopted as the raw material monomer as long as it is a monomer having an ethylenically unsaturated group. In order to obtain an alicyclic hydrocarbon group-containing polymer suitable as a resist resin, it is preferable to use at least one (meth) acrylic acid ester as a monomer. More preferably, it is a (meth) acrylic acid ester containing an alicyclic hydrocarbon group as an ester group. By using such a (meth) acrylic acid ester, it becomes possible to obtain an alicyclic hydrocarbon group-containing polymer excellent in resist performance such as transparency, dry etching resistance and adhesion.

  Examples of the alicyclic hydrocarbon group as the ester group include an adamantyl group, a norbornane lactyl group, a γ-butyrolactyl group, a group to which a substituent such as an alkyl group, a hydroxyl group, and a carboxyl group is attached. Can be mentioned.

  Examples of the (meth) acrylic acid ester containing the alicyclic hydrocarbon group as an ester group include 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, and α-hydroxy -Γ-butyrolactyl (meth) acrylate, norbornane carbolactyl (meth) acrylate, 3-hydroxy-1-adamantyl (meth) acrylate and the like.

  The weight average molecular weight of the alicyclic hydrocarbon group-containing polymer of the present invention is preferably 2000 to 300000, more preferably 3000 to 30000, in order to obtain a polymer suitable as a resist material. The weight average molecular weight of the polymer can be adjusted by the use ratio of the monomer amount and the chain transfer agent, or the polymerization time.

  The polydispersity Mw / Mn of the alicyclic hydrocarbon group-containing polymer of the present invention is preferably 1.6 or less, and more preferably 1.5, in order to obtain a polymer having excellent line edge roughness. Hereinafter, it is more preferably 1.4 or less.

  In order for the alicyclic hydrocarbon group-containing polymer of the present invention to be a polymer suitable as a resist material, the transmittance of ultraviolet rays having a wavelength of 193 nm per 200 nm thickness is preferably 70% or more, more preferably. Is 75% or more.

In the alicyclic hydrocarbon group-containing polymer of the present invention, the residue of the chain transfer agent for living radical polymerization of the present invention can remain as a terminal group as a dormant species at the polymerization terminal. Specific examples of the residue of the chain transfer agent of the present invention preferably include a group having a structure represented by the general formula (4).

  Any appropriate radical polymerization initiator can be adopted as the radical polymerization initiator that can be used for producing the alicyclic hydrocarbon group-containing polymer of the present invention. Preferably, it is an initiator that generates radicals by heat. Specifically, for example, 2,2′-azobisbutyronitrile such as 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (2-methylbutyronitrile); 2,2′-azobisvaleronitriles such as 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile); 2,2'-azobispropionitriles such as 2'-azobis (2-hydroxymethylpropionitrile); 1,1'-azobis- such as 1,1'-azobis (cyclohexane-1-carbonitrile) 1-alkanenitriles; azo compounds such as 2,2′-azobis (isobutyric acid) dimethyl; di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide , Α, α′-bis (t-butylperoxy-m-isopropyl) benzene, dialkyl peroxides such as 2,5-di (t-butylperoxy) hexyne-3; t-butylperoxybenzoate, t -Peroxyesters such as butyl peroxyacetate and 2,5-dimethyl-2,5-di (benzoylperoxy) hexane; cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, etc. Ketone peroxides of 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, , 1-bis (t-butylperoxy) cyclohexane, n-butyl- Peroxyketals such as 1,4-bis (t-butylperoxy) valate; hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylcyclohexane-2,5-dihydroperoxide Diacyl peroxides such as benzoyl peroxide, decanoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide; peroxydicarbonates such as bis (t-butylcyclohexyl) peroxydicarbonate; An organic peroxide radical polymerization initiator can be used. Particularly preferred is AIBN which is easy to obtain and handle.

  Arbitrary appropriate manufacturing methods can be employ | adopted for the manufacturing method of the alicyclic hydrocarbon group containing polymer of this invention. Examples of the form of polymerization include bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and the like, but solution polymerization is preferred because of the convenience of handling the produced polymer.

  Any appropriate solvent can be adopted as a solvent that can be used for solution polymerization. For example, ethers and ketones are preferably mentioned, more preferably ethers having a boiling point near or above the polymerization temperature, and more preferably 1,4-dioxane and tetrahydrofuran.

  The monomer concentration at the time of polymerization is preferably 10 to 70% by weight, more preferably 20 to 60% by weight, from the convenience of handling.

  The polymerization reaction temperature depends on the type of monomer used and the type of polymerization initiator, but is a general temperature for radical polymerization and is preferably a temperature at which the monomer does not decompose. Specifically, it is preferably 20 to 120 ° C, more preferably 50 to 110 ° C, and further preferably 60 to 100 ° C.

  Polymerization may be carried out in a normal air atmosphere, but polymerization in an inert gas atmosphere such as nitrogen or argon is preferred.

  The polymerization time is preferably 0.5 to 144 hours, more preferably 2 to 24 hours.

  Any appropriate purification method can be adopted as a purification method of the polymer. For example, the following methods are mentioned. Liquid / liquid extraction method that removes residual monomer and oligomer components by combining water washing and an appropriate solvent as a method of removing residual monomers and oligomer components below the specified value; Purification method in a solution state such as outer filtration; reprecipitation method in which a polymer solution is dripped into a poor solvent to solidify the polymer in the poor solvent to remove residual monomers, etc .; And a purification method in a solid state such as washing with a poor solvent. These methods can also be combined. Any appropriate poor solvent can be adopted as the poor solvent used in the reprecipitation method.

[Use of alicyclic hydrocarbon group-containing polymer]
The alicyclic hydrocarbon group-containing polymer of the present invention can be applied to any appropriate use. For example, it can be suitably used as an optical resin material such as an optical lens, an optical disk, an optical fiber, or an optical film, or as a resist resin material for fine processing. Among these uses, the resist is excellent in light transmittance at the exposure light source wavelength at a practical level of film thickness, and the line edge roughness is favorably improved because the polydispersity Mw / Mn is small. It is particularly preferable to use it as a resin.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

(Identification of monomer and chain transfer agent)
Identification was carried out by IR and NMR measurements. IR measurement was performed by 32 times of integration by a liquid film method using a KBr cell, using MAGNA-IR760 type FT-IR manufactured by Nicorey Japan. NMR measurement was performed by using a JNM-GSX270 type FT-NMR manufactured by JEOL Ltd., and a sample dissolved in deuterated chloroform containing 0.03% tetramethylsilane as a standard substance. ¹ H-NMR measurement was performed 32 times, and ¹³ C-NMR measurement was performed 512 times.

[Average copolymer composition ratio of copolymer (mol%)]
^It calculated | required by the measurement of < ¹ > H-NMR. This measurement uses a JNM-GSX270 type FT-NMR manufactured by JEOL Ltd. and a sample dissolved in deuterated chloroform containing 0.03% tetramethylsilane as a standard substance, and a tube for NMR measurement having a diameter of 5 mm. And was accumulated 64 times.

[Average molecular weight of copolymer]
About 20 mg of the copolymer was dissolved in 5 mL of tetrahydrofuran, and the sample solution filtered through a 0.5 μm membrane filter was measured using Gel Permeation Chromatography (GPC) manufactured by JASCO Corporation. The separation column uses two Shodex GPC KF-804L manufactured by Showa Denko Co., Ltd. in series. Tetrahydrofuran is used as the elution solvent, the flow rate is 1.0 mL / min, the injection amount is 0.1 mL, and the measurement temperature is 40 ° C. went. The detector used was a RI-930 differential refractometer manufactured by JASCO Corporation, and polystyrene was used as the standard polymer.

[Measurement of transmittance of copolymer thin film]
By applying a propylene glycol methyl ether acetate (PGMEA) solution containing 10% by weight of a copolymer on a quartz plate having a thickness of 1 mm by spin coating, baking on a hot plate at 110 ° C. for 60 seconds and cooling. A copolymer thin film having a thickness of 200 nm was prepared on a quartz plate. The light transmittance at a wavelength of 193 nm of the copolymer thin film sample was measured using a U-2000 type UV-visible spectrophotometer manufactured by Hitachi, with reference to a quartz plate on which the copolymer thin film was not applied. .

[Refractive index measurement of copolymer thin film]
A propylene glycol methyl ether acetate (PGMEA) solution containing 10% by weight of a copolymer is applied onto a silicon wafer by spin coating, baked on a hot plate at 110 ° C. for 60 seconds, and cooled to cool the silicon wafer. A copolymer thin film having a thickness of 200 nm was prepared. The refractive index of the copolymer thin film sample at a wavelength of 589 nm was measured using an F20 type thin film measuring apparatus manufactured by Filmetrics Co., Ltd.

[Synthesis Example 1]: Synthesis of 2-methyl-2-adamantyl methacrylate A stirring bar was placed in a 200 mL three-necked flask equipped with a reflux condenser, a calcium chloride tube, a thermometer, and a dropping funnel, and 2-methyl-2-adaman was obtained. 8.31 g (50.0 mmol) of ethanol, 9.11 g (90.0 mmol) of triethylamine, and 50 mL of methyl isobutyl ketone (MIBK) were added and stirred at 60 ° C. 7.84 g (75.0 mmol) of methacrylic acid chloride previously placed in the dropping funnel was dropped into the reaction system over 1 hour. After completion of the dropwise addition, the reaction mixture was stirred at 60 ° C. for 24 hours. After cooling the reaction mixture, insoluble matters were removed by filtration, and the filtrate was washed with water, 10 wt% aqueous sodium carbonate solution and saturated brine in that order, and the organic layer was extracted. The extracted organic layer was dried over anhydrous magnesium sulfate, the dried organic layer was filtered, and 2.5 g of activated carbon was added to the filtrate for decolorization treatment. After filtration, the filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography to obtain 9.96 g (yield: 85.0%) of 2-methyl-2-adamantyl methacrylate, which was the target product, as colorless. Obtained as a clear liquid.

The IR, ¹ H-NMR, and ¹³ C-NMR data of the obtained 2-methyl-2-adamantyl methacrylate are as follows.

IR (neat, ν, cm ⁻¹ ): 3102, 2910, 2862, 1789, 1713, 1636, 1448, 1263, 1172, 1104, 1045.
¹ H-NMR (CDCl ₃ , δ, ppm): 6.05 (s, 1H), 5.49 (s, 1H), 2.35 to 1.34 (m, 17H), 1.94 (s, 3H).
¹³ C-NMR (CDCl ₃ , δ, ppm): 166.09, 137.94, 124.09, 86.83, 38.21, 36.27, 34.52, 33.18, 27.42, 26 79, 22.30, 18.60.

[Synthesis Example 2]: Synthesis of γ-butyrolactone-2-yl methacrylate A stirrer was placed in a 200 mL three-necked flask equipped with a reflux condenser, a calcium chloride tube, a thermometer, and a dropping funnel, and α-hydroxy-γ-butyrolactone was added. 8.68 g (85.0 mmol), triethylamine 15.18 g (150.0 mmol), and methyl isobutyl ketone (MIBK) 100 mL were added and stirred at room temperature. 10.45 g (100.0 mmol) of methacrylic acid chloride previously placed in the dropping funnel was dropped into the reaction system over 1.5 hours. After completion of the dropwise addition, the reaction mixture was stirred at room temperature for 24 hours. Insoluble matters were removed from the reaction mixture by filtration, and the filtrate was washed successively with water, 10 wt% aqueous sodium carbonate solution and saturated brine, and the organic layer was extracted. The extracted organic layer was dried over anhydrous magnesium sulfate, the dried organic layer was filtered, and 3.5 g of activated carbon was added to the filtrate for decolorization treatment. After filtration, the filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography to obtain 11.92 g (yield: 82.4%) of the target product, γ-butyrolactone-2-yl methacrylate. Obtained as a yellow clear liquid.

The IR, ¹ H-NMR, and ¹³ C-NMR data of the obtained γ-butyrolactone-2-yl methacrylate are as follows.

IR (neat, ν, cm ⁻¹ ): 3101, 2987, 2929, 1786, 1728, 1637, 1454, 1297, 1155, 1109.
¹ H-NMR (CDCl ₃ , δ, ppm): 6.22 (s, 1H), 5.68 (s, 1H), 5.48 (t, 1H), 4.50 (dd, 1H), 4 .34 (d, 1H), 2.75 (dd, 1H), 2.35 (d, 1H), 1.99 (s, 3H).
¹³ C-NMR (CDCl ₃ , δ, ppm): 172.47, 165.81, 134.83, 127.26, 67.80, 65.00, 38.21, 36.27, 28.87, 18 .13.

Example 1 Synthesis of 2-cyanoprop-2-yldithiopropionate (1)
A stirrer was placed in a 300 mL four-necked flask equipped with a reflux condenser, a dropping funnel, a septum cap, and an argon gas introduction tube, and the system was replaced with argon gas. 100 mL (1.0 M in THF, 100.0 mmol) of ethylmagnesium bromide was added from the septum cap into the system with a syringe and stirred at room temperature. 6.85 g (90.0 mmol) of carbon disulfide previously placed in the dropping funnel was dropped into the reaction system in 5 minutes. After completion of the dropwise addition, the reaction mixture was stirred at 40 ° C. for 2 hours. The reaction mixture was cooled to room temperature and quenched by slowly adding into 250 g of ice water. The aqueous layer was washed 3 times with diethyl ether, and impurities were transferred to the organic layer and removed. Furthermore, the organic layer was extracted by adding diethyl ether to the washed aqueous layer and adding concentrated hydrochloric acid to make it acidic. The extracted organic layer was dried over anhydrous magnesium sulfate, the dried organic layer was filtered, and the filtrate was concentrated under reduced pressure to obtain 6.50 g (yield 68.0%) of dithiopropionic acid as a deep red liquid. Got as. The obtained dithiopropionic acid was used in the next reaction as it was.

  A stirrer was placed in a 50 mL three-necked flask equipped with a reflux condenser, a dropping funnel, and an argon gas introduction tube, and the system was replaced with argon gas. In the system, 2.50 g (23.5 mmol) of dithiopropionic acid and 15 mL of toluene were added and stirred at room temperature. 2.37 g (35.3 mmol) of (meth) acrylonitrile previously placed in the dropping funnel was dropped into the reaction system in 5 minutes. After completion of the dropwise addition, the reaction mixture was stirred at 80 ° C. for 24 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. By purifying the obtained residue by silica gel column chromatography, 1.86 g of 2-cyanoprop-2-yldithiopropionate (yield 45.7%, total yield of all 2 steps 31.1%) was obtained. Obtained as a red liquid.

IR, ¹ H-NMR, and ¹³ C-NMR data of the obtained 2-cyanoprop-2-yldithiopropionate are as follows.

IR (neat, ν, cm ⁻¹ ): 2979, 2935, 2876, 2241, 1454, 1187.
¹ H-NMR (CDCl ₃ , δ, ppm): 3.43 (q, 2H), 3.05 (t, 3H), 1.40 (s, 6H).
¹³ C-NMR (CDCl ₃ , δ, ppm): 121.24, 45.22, 38.43, 24.93, 17.77, 15.40.

Example 2 Synthesis of 2-cyanoprop-2-yldithiopropionate (2)
A stirrer was placed in a 50 mL three-necked flask equipped with a reflux condenser, a dropping funnel, and an argon gas introduction tube, and the system was replaced with argon gas. In the system, 5.70 g (53.7 mmol) of dithiopropionic acid obtained in the same manner as Example 1 and 50 mL of toluene were added and stirred at room temperature. 9.51 g (80.5 mmol) of α-methylstyrene that had been put in the dropping funnel in advance was dropped into the reaction system in 15 minutes. After completion of the dropwise addition, the reaction mixture was stirred at 80 ° C. for 24 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography to obtain 6.10 g (yield 50.6%) of 2-phenylprop-2-yldithiopropionate as a red liquid.

The IR, ¹ H-NMR, and ¹³ C-NMR data of the obtained 2-phenylprop-2-yldithiopropionate are as follows.

IR (neat, ν, cm ⁻¹ ): 3087, 3058, 3024, 2970, 2932, 2870, 1447, 1188.
¹ H-NMR (CDCl ₃ , δ, ppm): 7.49-7.19 (m, 5H), 2.83 (q, 2H), 1.91 (s, 6H), 1.25 (t, 3H).
¹³ C-NMR (CDCl ₃ , δ, ppm): 140.02, 127.85, 126.85, 126.38, 55.69, 46.14, 27.96, 15.45.

  A stirrer was placed in a 50 mL three-necked flask equipped with a reflux condenser and an argon gas introduction tube, and the system was replaced with argon gas. To the system, 5.61 g (25.0 mmol) of 2-phenylprop-2-yldithiopropionate obtained as described above, 8.21 g (50.0 mmol) of AIBN, and 30 mL of toluene were added, and the mixture was stirred at 80 ° C. for 24 hours. Stir for hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. By purifying the obtained residue by silica gel column chromatography, 1.70 g of 2-cyanoprop-2-yldithiopropionate (yield: 39.2%, total yield of all three steps: 13.5%) was obtained. Obtained as a red liquid.

The IR, ¹ H-NMR, and ¹³ C-NMR data of the obtained 2-cyanoprop-2-yldithiopropionate were the same as those in Example 1.

[Example 3]: Synthesis of alicyclic hydrocarbon group-containing polymer (1)
In a reaction vessel containing a stirring bar, 4.68 g (20.0 mmol) of 2-methyl-2-adamantyl methacrylate, 3.40 g (20.0 mol) of γ-butyrolactone-2-yl methacrylate, 0.50 g of AIBN (3.0 mmol) ), 0.52 g (3.0 mmol) of 2-cyanoprop-2-yldithiopropionate and 20 mL of 1,4-dioxane, and stirred at 80 ° C. for 6 hours under an argon atmosphere. After the reaction, the precipitate formed by dropping into 400 mL of methanol was filtered off with a glass filter. The recovered precipitate was dried under reduced pressure and then dissolved in tetrahydrofuran, and the precipitation and drying operations were repeated to obtain 5.80 g of a copolymer (conversion rate: 71.8%) as a white powder.

  The average copolymer composition ratio (mol%) of the obtained copolymer was adamantyl moiety: lactone moiety = 52.5: 47.5, weight average molecular weight (Mw) was 5000, number average molecular weight (Mn) was 3700, and many The dispersity (Mw / Mn) was 1.35. Further, this copolymer had a transmittance of 79.0% at a wavelength of 193 nm and a refractive index of 1.62 at a wavelength of 589 nm.

[Example 4]: Synthesis of polymer containing alicyclic hydrocarbon group (2)
In a reaction vessel containing a stirring bar, 4.68 g (20.0 mmol) of 2-methyl-2-adamantyl methacrylate, 3.40 g (20.0 mol) of γ-butyrolactone-2-yl methacrylate, 0.50 g of AIBN (3.0 mmol) ), 0.52 g (3.0 mmol) of 2-cyanoprop-2-yldithiopropionate and 20 mL of 1,4-dioxane, and stirred at 80 ° C. for 12 hours under an argon atmosphere. After the reaction, the precipitate formed by dropping into 400 mL of methanol was filtered off with a glass filter. The collected precipitate was dried under reduced pressure and then dissolved in tetrahydrofuran, and the precipitation and drying operations were repeated to obtain 4.61 g of a copolymer (conversion rate: 57.0%) as a white powder.

  The average copolymer composition ratio (mol%) of the obtained copolymer was adamantyl moiety: lactone moiety = 51.3: 48.7, the weight average molecular weight (Mw) was 5300, the number average molecular weight (Mn) was 3900, and many The dispersity (Mw / Mn) was 1.35. Further, this copolymer had a transmittance of 79.2% at a wavelength of 193 nm and a refractive index of 1.62 at a wavelength of 589 nm.

[Comparative Example 1]: Synthesis of alicyclic hydrocarbon group-containing polymer (3)
In a reaction vessel containing a stirring bar, 4.68 g (20.0 mmol) of 2-methyl-2-adamantyl methacrylate, 3.40 g (20.0 mol) of γ-butyrolactone-2-yl methacrylate, 1.0 g of AIBN (6.0 mmol) ), 20 ml of 1,4-dioxane, and stirred at 80 ° C. for 6 hours under an argon atmosphere. After the reaction, the precipitate formed by dropping into 400 mL of methanol was filtered off with a glass filter. The collected precipitate was dried under reduced pressure and then dissolved in tetrahydrofuran, and the precipitation and drying operations were repeated to obtain 5.83 g of copolymer (conversion 72.1%) as a white powder.

  The average copolymer composition ratio (mol%) of the obtained copolymer was adamantyl moiety: lactone moiety = 51.1: 48.9, weight average molecular weight (Mw) was 6700, number average molecular weight (Mn) was 3000, and many The dispersity (Mw / Mn) was 2.23. Further, this copolymer had a transmittance of 80.4% at a wavelength of 193 nm and a refractive index of 1.62 at a wavelength of 589 nm.

According to the present invention, it is possible to produce a resist resin having excellent basic characteristics such as narrow dispersibility and high transmittance for a corresponding wavelength by a simple process. Therefore, the polymer of the present invention can be suitably used as a resist material that can be applied to short-wavelength ultraviolet light corresponding to miniaturization in semiconductor elements and the like that are expected to further develop technology in the future.

Claims (8)

A chain transfer agent for living radical polymerization having a structure represented by the general formula (1).

(In general formula (1), R ₁ represents a saturated hydrocarbon group, and R ₂ represents a saturated hydrocarbon group having a cyano group.) The chain transfer agent of Claim 1 obtained by making the compound which has a structure represented by General formula (2), and the compound which has a structure represented by General formula (3) react.

(In general formula (2), R ₁ represents a saturated hydrocarbon group.)

(In general formula (3), R ₃ , R ₄ , and R ₅ represent a hydrogen atom or a saturated hydrocarbon group.)   The chain transfer agent according to claim 2, wherein the compound having the structure represented by the general formula (3) is (meth) acrylonitrile. A polymer obtained by conducting living radical polymerization using the chain transfer agent according to any one of claims 1 to 3,
An alicyclic hydrocarbon group-containing polymer which has an acid dissociable group and is alkali-insoluble or alkali-insoluble.   The polymer according to claim 4, which is obtained by conducting living radical polymerization using at least one (meth) acrylic acid ester as a raw material.   The polymer according to claim 5, wherein the (meth) acrylic acid ester contains an alicyclic hydrocarbon group as an ester group.   The polymer according to any one of claims 4 to 6, wherein the polydispersity Mw / Mn is 1.6 or less, and the transmittance of ultraviolet rays having a wavelength of 193 nm per 200 nm thickness is 70% or more. The polymer according to claims 4 to 7, which is a resist resin.