JP5820354B2 - Method for producing polymer and method for producing resist composition - Google Patents

Description

  The present invention relates to a method for producing a polymer, a polymer, and a resist composition.

  In recent years, resist patterns formed in the manufacturing process of semiconductor elements, liquid crystal elements, and the like have been rapidly miniaturized due to advances in lithography technology. As a resist composition used for forming a resist pattern, a chemically amplified resist containing a photoacid generator that generates an acid upon irradiation with radiation and a resin whose alkali solubility is changed by the action of the generated acid is known. It has been.

  As a resin for a chemically amplified resist composition used in the formation of a resist pattern using an ArF excimer laser (wavelength 193 nm), an acrylic polymer that is transparent to light with a wavelength of 193 nm has attracted attention. As the polymer, for example, a polymer of a monomer having a lactone skeleton, a monomer having an acid leaving group, and a monomer having a hydrophilic group is known (Patent Document 1). ).

The polymer is produced, for example, by the following method (Example of Patent Document 1).
A monomer solution containing a monomer component such as a monomer having a lactone skeleton, a monomer having an acid-eliminable group, a monomer having a hydrophilic group, a polymerization initiator, and a solvent A method in which the monomer component is polymerized in a polymerization tank by dropping into a solvent kept at the polymerization temperature inside.

However, the polymer obtained by this method may cause the following problems.
Resist pattern obtained by developing the resist film, because the resist film made of the resist composition containing the obtained polymer cannot exhibit the performance as designed (solubility in developer, sensitivity, resolution, etc.). The accuracy, yield, etc. of the circuit formed by using this decrease.
When developing a resist film, a development defect called a defect occurs, the defect causes a loss of a resist pattern, and a circuit formed using the resist pattern is disconnected or has a defect.

International Publication No. 03/082933 Pamphlet

  The present invention relates to a polymer capable of exhibiting performance as designed in an intended application, a method for producing the same, and a resist composition capable of exhibiting performance as designed in a resist film and suppressing the occurrence of defects in a resist pattern. I will provide a.

In the method for producing a polymer of the present invention, a monomer solution containing a monomer component and a polymerization initiator stored in a container is dropped into a solvent maintained at a polymerization temperature in a polymerization tank, and is simply added. A step of polymerizing a monomer component, the polymerization initiator is dimethyl-2,2′-azobisisobutyrate, and the temperature of the monomer solution in the container is kept at 10 to 35 ° C., In addition, by adjusting the temperature of the monomer solution in the supply pipe that supplies the monomer solution in the container to the polymerization tank, the fluctuation range of the temperature of the monomer solution at the outlet of the supply pipe is set to 6 ° C. or less. And the fluctuation range of the polymerization temperature is kept at 4 ° C. or lower.
The polymer production method of the present invention is preferably a method for producing a polymer for ArF excimer laser lithography.

  The method for producing a resist composition of the present invention is characterized in that a polymer is produced by the method for producing a polymer of the present invention, and the obtained polymer and a photoacid generator are dissolved in a solvent.

According to the method for producing a polymer of the present invention, it is possible to produce a polymer that can exhibit the performance as designed in the intended application.
The polymer of the present invention can exhibit the performance as designed in the intended application.
The resist composition of the present invention can cause the resist film to exhibit the performance as designed and suppress the occurrence of defects in the resist pattern.

It is a block diagram which shows an example of the manufacturing equipment of a polymer.

  Hereinafter, the monomer represented by the formula (1-1) is referred to as a monomer (1-1). The same applies to monomers represented by other formulas. Moreover, (meth) acrylic acid means methacrylic acid or acrylic acid, and (meth) acrylic acid ester means methacrylic acid ester or acrylic acid ester.

<Method for producing polymer>
In the method for producing a polymer of the present invention, a monomer solution containing a monomer component and a polymerization initiator stored in a container is dropped into a solvent maintained at a polymerization temperature in a polymerization tank, and is simply added. The method has a step of polymerizing the monomer component, and the temperature fluctuation range of the monomer solution dropped into the polymerization tank is maintained at 6 ° C. or less.

Examples of the monomer component include known monomers. For example, (meth) acrylic acid ester, aromatic alkenyl compound, unsaturated dicarboxylic acid anhydride, olefin, fluorine-containing monomer, acrylamide, vinyl chloride Etc.
As a polymerization initiator, a well-known polymerization initiator is mentioned, For example, an azo compound, an organic peroxide, etc. are mentioned.
As a solvent, the solvent which can melt | dissolve any of a monomer component, a polymerization initiator, and the polymer obtained is mentioned. The solvent is preferably an electronic industrial grade solvent.

Examples of the resulting polymer include acrylic polymers, styrene polymers (polystyrene, acrylonitrile-butadiene-styrene copolymers, etc.), vinyl chloride polymers, polyester polymers, cycloolefin polymers, vinyl ether polymers. Examples thereof include a polymer, a fluorine polymer, and an epoxy polymer.
Examples of the polymer include a resist polymer, an antireflection polymer, a coating polymer, a toner polymer, a molding polymer, and the like depending on applications.
The method for producing a polymer of the present invention is suitable for producing a resist polymer that is required to have a small deviation in target molecular weight and molecular weight distribution.

  In the present invention, the temperature of the monomer solution stored in the container is preferably maintained at 10 to 35 ° C, more preferably 20 to 30 ° C. By setting the temperature to 20 ° C. or higher, the temperature change of the solution in the polymerization tank immediately after the start of dropping is small. By setting the temperature to 35 ° C. or lower, polymerization of the monomer component in the monomer solution before dropping is suppressed.

  In the present invention, it is necessary to keep the fluctuation range of the temperature of the monomer solution dropped into the polymerization tank at 6 ° C. or less, and it is preferable to keep the fluctuation range at 4 ° C. or less. The temperature is the temperature of the monomer solution immediately before being dropped into the polymerization tank, and is, for example, the temperature of the monomer solution at the outlet of a supply pipe that supplies the monomer solution to the polymerization tank. The fluctuation range means a difference between the maximum temperature of the monomer solution dropped into the polymerization tank from the start of dropping to the end of dropping and the minimum temperature of the monomer solution dropped into the polymerization tank. By keeping the fluctuation range at 6 ° C. or less, it is possible to suppress the deviation of the molecular weight and molecular weight distribution of the obtained polymer from the target molecular weight and molecular weight distribution.

  The temperature of the monomer solution is adjusted by measuring the temperature of the monomer solution in the container, in the supply pipe for supplying the monomer solution in the container to the polymerization tank, at the outlet of the supply pipe, and the like. This is done by adjusting the temperature of the temperature control means provided in the container or the supply pipe. Examples of the temperature adjusting means include a jacket provided in the container, an internal coil, a heat exchanger provided in the middle of a supply pipe for supplying the monomer solution in the container to the polymerization tank.

The polymerization temperature is preferably 50 ° C. or higher, and preferably 150 ° C. or lower.
In the present invention, the fluctuation range of the polymerization temperature is preferably kept at 4 ° C. or less, and more preferably kept at 2 ° C. or less. The fluctuation range means a difference between the maximum temperature of the solution in the polymerization tank and the minimum temperature of the solution in the polymerization tank from the start of dropping of the monomer solution to the end of polymerization. Moreover, the completion | finish of superposition | polymerization means the time of starting cooling of the polymer solution in a superposition | polymerization tank after progress of predetermined superposition | polymerization time. By keeping the fluctuation range at 4 ° C. or less, it is possible to suppress the deviation of the molecular weight and molecular weight distribution of the obtained polymer from the target molecular weight and molecular weight distribution.

The polymerization temperature is adjusted by measuring the temperature of the solution in the polymerization tank and adjusting the temperature of the temperature adjusting means based on the temperature. Examples of temperature control means include a jacket provided in the polymerization tank, an internal coil, and the like.
The polymerization time is preferably 1 hour or longer, and preferably 24 hours or shorter.

  In the present invention, by maintaining the temperature fluctuation range of the monomer solution dropped into the polymerization tank at 6 ° C. or less, the resist film can perform as designed, and the occurrence of defects in the resist pattern can be suppressed. Can be produced. The reason for this is as follows.

  The inventors of the present invention have problems that the resist film cannot exhibit the performance as designed and the problem of the occurrence of defects in the resist pattern that the molecular weight and molecular weight distribution of the resulting polymer greatly deviate from the target molecular weight and molecular weight distribution. I found out that it was caused by that. That is, when the molecular weight of the resulting polymer is large and the molecular weight distribution is wide compared to the target molecular weight and molecular weight distribution, the polymer remains undissolved when the polymer is dissolved in a resist solvent, The undissolved polymer is generated as a defect in the resist pattern. Further, if the molecular weight and molecular weight distribution of the polymer obtained are greatly deviated from the target molecular weight and molecular weight distribution, the resist film made of the resist composition containing the polymer cannot exhibit the performance as designed.

  Therefore, as a result of studies to suppress the deviation of the molecular weight and molecular weight distribution of the obtained polymer from the target molecular weight and molecular weight distribution, the inventors have not adjusted the temperature of the monomer solution as in the past. In this case, the temperature of the monomer solution dripped into the polymerization tank greatly fluctuates between the start of dripping and the end of dripping, and accordingly, the polymerization temperature in the polymerization tank fluctuates greatly, from the target molecular weight and molecular weight distribution. The molecular weight and molecular weight distribution of the resulting polymer were found to be greatly deviated. Therefore, the temperature fluctuation range of the monomer solution dropped into the polymerization tank was kept at 6 ° C. or less.

  Also, in polymers other than resist polymers, the weight obtained from the target molecular weight and molecular weight distribution can be obtained by keeping the temperature fluctuation range of the monomer solution dropped into the polymerization tank at 6 ° C. or less. It is suppressed that the molecular weight and molecular weight distribution of the coalesced are greatly deviated, and a polymer capable of exhibiting the performance as designed in the intended use is obtained.

(Method for producing resist polymer)
Hereinafter, a method for producing a resist polymer will be specifically described.
The resist polymer is manufactured through the following steps, for example.
(A) A step of preparing a monomer solution containing a monomer component and a polymerization initiator.
(B) A step of dropping the monomer solution stored in the container into a solvent kept at the polymerization temperature in the polymerization tank to polymerize the monomer components to obtain a polymer solution.
(C) A step of pouring the polymer solution into a poor solvent in the container to precipitate the polymer to obtain a polymer dispersion.
(D) A step of recovering the polymer by filtering the polymer dispersion using a filter.
(E) A step of dispersing the recovered polymer in a poor solvent to obtain a polymer dispersion.
(F) A step of filtering the polymer dispersion using a filter to recover the polymer.

The recovered polymer becomes a final product through (g) a step of drying the recovered polymer to obtain a powder product, or the following steps.
(H) A step of dissolving the recovered polymer in a good solvent to obtain a polymer solution.
(I) A step of removing impurities by passing the polymer solution through a precision filter.
(J) A step of removing the remaining poor solvent from the polymer solution that has passed through the precision filter, and further concentrating the polymer solution.

(A) Process:
A raw material (a monomer component, a polymerization initiator, a dropping solvent, etc.) is injected into a mixing tank 10 (container) having a stirrer 12, a jacket (not shown) and a condenser 14 shown in FIG. A monomer solution is prepared.

  As the monomer component, those containing a monomer (1) having a lactone skeleton and a monomer (2) having an acid-eliminable group are preferred, and further a monomer (3) having a hydrophilic group The thing containing is preferable. The monomer component may contain the monomer (4) having a nonpolar alicyclic skeleton, or may contain another monomer (5).

The monomer (1) having a lactone skeleton is a component that improves the adhesion of the resist film to the substrate. Moreover, if the monomer (1) having a lactone skeleton has an acid-eliminable group, the adhesion and sensitivity of the resist film are improved. If the monomer (1) having a lactone skeleton has a hydrophilic group, the adhesion of the resist film and the rectangularity of the resist pattern are improved.
The monomer (1) having a lactone skeleton is a monomer having a cyclic saturated hydrocarbon group containing a carbonyloxy group (—C (O) O—) in the ring.

  The amount of the monomer (1) having a lactone skeleton is preferably 30 mol% or more, more preferably 35 mol% or more in the monomer component (100 mol%) from the viewpoint of adhesion of the resist film to the substrate. preferable. The amount of the monomer (1) having a lactone skeleton is preferably 60 mol% or less, more preferably 55 mol% or less, from the viewpoint of the sensitivity and resolution of the resist film. As the monomer (1) having a lactone skeleton, one type may be used alone, or two or more types may be used in combination.

Examples of the monomer (1) having a lactone skeleton include known monomers used in the production of resist polymers, and resists using ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm). In view of obtaining a polymer suitable for pattern formation, a (meth) acrylic acid ester having a lactone skeleton is preferred.
As the monomer having a lactone skeleton, monomers (1-1) to (1-29) are preferable. However, R represents a hydrogen atom or a methyl group.

  The monomer (2) having an acid leaving group (excluding a monomer having a lactone skeleton) is a component that improves the sensitivity of the resist film. Further, if the monomer (2) having an acid leaving group has a hydrophilic group, the sensitivity of the resist film is further improved.

The acid leaving group is a group having a bond that is cleaved by an acid generated from the photoacid generator, and part or all of the acid leaving group is released from the main chain of the polymer by cleavage of the bond. It is a group. As an acid leaving group, the ester group which the following groups couple | bonded with the oxygen atom of the carbonyloxy group (-C (O) O-) is mentioned, for example.
A branched tertiary alkyl group, an alkyl-substituted hydrocarbon group represented by the following formula (wherein R ¹¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms, and R ¹² represents a carbon to which it is bonded. Represents a group that forms a hydrocarbon group with an atom.), An alkoxyalkyl group, a group represented by —R ¹³ —O—R ¹⁴ —R ¹⁵ (wherein R ¹³ is a straight chain having 1 to 6 carbon atoms) A linear or branched alkylene group, R ¹⁴ represents a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms, and R ¹⁵ represents a hydrocarbon group.), A tetrahydropyranyl group , Tetrahydrofuranyl group and the like.

Examples of the branched tertiary alkyl group include a t-butyl group and a t-pentyl group.
Examples of the alkoxyalkyl group include a methoxymethyl group, 1-methoxyethyl group, ethoxymethyl group, 1-ethoxyethyl group, isopropoxymethyl group, 1-isopropoxyethyl group, cyclohexoxymethyl group, 1-cyclohexoxyethyl group, Examples include a cyclopentoxymethyl group and a 1-cyclopentoxyethyl group.

The hydrocarbon group is preferably a saturated alicyclic hydrocarbon group from the viewpoint of high light transmittance when a resist polymer is used. Examples of the saturated alicyclic hydrocarbon group include a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic hydrocarbon group.
Monocyclic alicyclic hydrocarbon groups include, for example, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, etc. From the viewpoint of superiority, a cyclopentyl group and a cyclohexyl group are preferable.
Examples of the polycyclic alicyclic hydrocarbon group include a bridged cyclic hydrocarbon group, a spirane hydrocarbon group, a ring assembly type hydrocarbon group, and the like. Specific examples include bicyclo [2.2.1] heptyl group, tetracyclo [4.4.0.1 ^2,5 ] dodecyl group, 1-adamantyl group, 2-adamantyl group and the like.

  The amount of the monomer (2) having an acid leaving group is preferably 20 mol% or more, more preferably 25 mol% or more in the monomer component (100 mol%) from the viewpoint of the sensitivity and resolution of the resist film. More preferred. The amount of the monomer (2) having an acid leaving group is preferably 60 mol% or less, and more preferably 55 mol% or less, from the viewpoint of adhesion of the resist film to the substrate. As the monomer (2) having an acid leaving group, one type may be used alone, or two or more types may be used in combination.

Examples of the monomer (2) having an acid leaving group include known monomers used for the production of resist polymers. ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) is used. A (meth) acrylic acid ester having an acid leaving group is preferred from the viewpoint of obtaining a polymer suitable for forming the used resist pattern.
As the (meth) acrylic acid ester having an acid leaving group, monomers (2-1) to (2-28) are preferable. However, R and R ′ represent a hydrogen atom or a methyl group.

The monomer (3) having a hydrophilic group (excluding a monomer having a lactone skeleton and a monomer having an acid leaving group) is a component that improves the rectangularity of the resist pattern.
The hydrophilic group is at least one selected from the group consisting of —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, a methoxy group, a carboxy group, and an amino group.

  The amount of the monomer (3) having a hydrophilic group is preferably 5 mol% or more and more preferably 10 mol% or more in the monomer component (100 mol%) from the viewpoint of the rectangularity of the resist pattern. The amount of the monomer (3) having a hydrophilic group is preferably 30 mol% or less, and more preferably 25 mol% or less, from the viewpoints of adhesion of the resist film to the substrate and sensitivity. As the monomer (3) having a hydrophilic group, one type may be used alone, or two or more types may be used in combination.

Examples of the monomer (3) having a hydrophilic group include known monomers used for the production of resist polymers, and an ArF excimer laser (wavelength 193 nm) or a KrF excimer laser (wavelength 248 nm) was used. In view of obtaining a polymer suitable for forming a resist pattern, a (meth) acrylic acid ester having a hydrophilic group is preferred.
As the (meth) acrylic acid ester having a hydrophilic group, monomers (3-1) to (3-15) are preferable. However, R represents a hydrogen atom or a methyl group.

The monomer (4) having a nonpolar alicyclic skeleton (except for a monomer having a lactone skeleton, a monomer having an acid-eliminable group, and a monomer having a hydrophilic group), It is a component that improves the dry etching resistance of the resist pattern.
The amount of the monomer (4) having a nonpolar alicyclic skeleton is not particularly limited, but is preferably 20 mol% or less in the monomer component (100 mol%). As the monomer (4) having a nonpolar alicyclic skeleton, one type may be used alone, or two or more types may be used in combination.

Examples of the monomer (4) having a nonpolar alicyclic skeleton include known monomers used in the production of resist polymers, such as ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm). (Meth) acrylic acid ester having a nonpolar alicyclic skeleton is preferable from the viewpoint of obtaining a polymer suitable for forming a resist pattern using.
Examples of the (meth) acrylic acid ester having a nonpolar alicyclic skeleton include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, adamantyl (meth) acrylate, (meth) Examples include tricyclodecanyl acrylate and dicyclopentadienyl (meth) acrylate. The (meth) acrylic acid ester having a nonpolar alicyclic skeleton may have a linear or branched alkyl group having 1 to 6 carbon atoms on the alicyclic skeleton.
As the (meth) acrylic acid ester having a nonpolar alicyclic skeleton, monomers (4-1) to (4-5) are preferable. However, R represents a hydrogen atom or a methyl group.

Examples of other monomer (5) include methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Isopropyl, n-butyl (meth) acrylate, isobutyl (meth) acrylate, methoxymethyl (meth) acrylate, n-propoxyethyl (meth) acrylate, iso-propoxyethyl (meth) acrylate, (meth) acryl N-butoxyethyl acid, iso-butoxyethyl (meth) acrylate, tert-butoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) acrylic 2-hydroxy-n-propyl acid, 4-hydroxy-n-butyl (meth) acrylate, 2-methacrylic acid (meth) acrylate, 1-ethoxyethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoro- (meth) acrylic acid n-propyl, 2,2,3,3,3-pentafluoro-n-propyl (meth) acrylate, methyl α- (tri) fluoromethyl acrylate, ethyl α- (tri) fluoromethyl acrylate, α- 2-ethylhexyl (tri) fluoromethyl acrylate, n-propyl α- (tri) fluoromethyl acrylate, iso-propyl α- (tri) fluoromethyl acrylate, n-butyl α- (tri) fluoromethyl acrylate, iso-butyl α- (tri) fluoromethyl acrylate, tert-butyl α- (tri) fluoromethyl acrylate, α- (tri) Methoxymethyl fluoromethyl acrylate, ethoxyethyl α- (tri) fluoromethyl acrylate, n-propoxyethyl α- (tri) fluoromethyl acrylate, iso-propoxyethyl α- (tri) fluoromethyl acrylate, α- It has a linear or branched structure such as n-butoxyethyl (tri) fluoromethyl acrylate, iso-butoxyethyl α- (tri) fluoromethyl acrylate, tert-butoxyethyl α- (tri) fluoromethyl acrylate (meta ) Acrylic acid ester;
2-methyl-2,4-butanediol di (meth) acrylate, 2,5-dimethyl-2,5-hexanediol di (meth) acrylate, 1,4-butanediol di (1- (meth) acryloyloxy) Ethyl ether, 1,4-butanediol di (1- (meth) acryloyloxy) methyl ether, (meth) acryloyloxyethylene glycol dimer (1- (meth) acryloyloxy) ethyl ether, (meth) acryloyloxyethylene glycol dimer A polyfunctional (meth) acrylic acid ester having an acid-decomposable group such as (1- (meth) acryloyloxy) methyl ether;
Styrene, α-methylstyrene, vinyltoluene, p-hydroxystyrene, p-tert-butoxycarbonylhydroxystyrene, 3,5-di-tert-butyl-4-hydroxystyrene, 3,5-dimethyl-4-hydroxystyrene, aromatic alkenyl compounds such as p-tert-perfluorobutylstyrene and p- (2-hydroxy-iso-propyl) styrene;
Unsaturated carboxylic acids and carboxylic anhydrides such as (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride;
Ethylene, propylene, norbornene, tetrafluoroethylene, acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, vinyl chloride, vinyl fluoride, vinylidene fluoride, vinylpyrrolidone;
And monomers (5-1) to (5-15). However, R represents a hydrogen atom or a methyl group.

  The amount of the other monomer (5) is not particularly limited, but is preferably 20 mol% or less in the monomer component (100 mol%). Another monomer (5) may be used individually by 1 type, and may be used in combination of 2 or more type.

As the polymerization initiator, those that generate radicals efficiently by heat are preferable. Examples of such a polymerization initiator include 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate, 2,2′-azobis [2- (2-imidazoline- Azo compounds such as 2-yl) propane]; organic peroxides such as 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane and di (4-tert-butylcyclohexyl) peroxydicarbonate Etc.
In the case where the polymer obtained by the production method of the present invention is used for an ArF excimer laser (wavelength: 193 nm) lithography application, a polymerization initiator is used because the light transmittance (transmittance with respect to light having a wavelength of 193 nm) is not reduced as much as possible. As for, what does not have an aromatic ring in molecular structure is preferable. In consideration of safety during polymerization, the polymerization initiator preferably has a 10-hour half-life temperature of 60 ° C. or higher.
The amount of the polymerization initiator is not particularly limited, but is preferably 0.3 mol parts or more, more preferably 1 mol parts or more with respect to 100 mol parts of the monomer component, from the viewpoint of increasing the yield of the polymer. Moreover, 30 mol parts or less are preferable with respect to 100 mol parts of monomer components from the point which narrows the molecular weight distribution of a polymer.

As a dripping solvent, when using together a monomer component, a polymerization initiator, the polymer obtained, and a chain transfer agent, the solvent which can melt | dissolve all the chain transfer agents is preferable. Examples of the solvent include ethers (chain ethers such as diethyl ether and propylene glycol monomethyl ether, cyclic ethers such as tetrahydrofuran and 1,4-dioxane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, ethyl lactate). , Butyl lactate, propylene glycol monomethyl ether acetate, γ-butyrolactone, etc.), ketone (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), amide (N, N-dimethylacetamide, N, N-dimethylformamide, etc.), sulfoxide. (Dimethyl sulfoxide, etc.), hydrocarbons (aromatic hydrocarbons such as benzene, toluene, xylene, aliphatic hydrocarbons such as hexane, alicyclic hydrocarbons such as cyclohexane, etc.), mixed solvents thereof and the like. . A solvent may be used individually by 1 type and may use 2 or more types together. The solvent is preferably an electronic industrial grade solvent.
Although the monomer density | concentration of the monomer solution in the mixing tank 10 is not specifically limited, 5-50 mass% is preferable.

The monomer solution may contain a chain transfer agent as long as the storage stability of the resist composition is not hindered. By using a chain transfer agent, a polymer having a low molecular weight and a small molecular weight distribution can be produced. Examples of the chain transfer agent include 1-butanethiol, 2-butanethiol, 1-octanethiol, 1-decanethiol, 1-tetradecanethiol, cyclohexanethiol, 2-methyl-1-propanethiol, 2-mercaptoethanol, Examples include mercaptoacetic acid and 1-thioglycerol. As the chain transfer agent, those having no aromatic ring are preferable from the viewpoint of reducing the light transmittance (transmittance with respect to light having a wavelength of 193 nm) as much as possible.
The amount of the chain transfer agent is preferably 1 to 20 mole parts relative to the monomer component (100 mole parts).

(B) Process:
The charged solvent is injected into the polymerization tank 20 having the stirrer 22, the jacket (not shown) and the condenser 24 shown in FIG. 1, and the polymerization temperature is maintained. The monomer solution stored in the blending tank 10 (container) is supplied to the polymerization tank 20 and dropped into the charged solvent maintained at the polymerization temperature to polymerize the monomer components to obtain a polymer solution.

As a preparation solvent, the dripping solvent used at the (a) process is mentioned.
The amount of the solvent is the total amount of the dropping solvent and the charged solvent, and is preferably 30 to 700 parts by mass with respect to the monomer component (100 parts by mass).
When two or more solvents are used in the dropping polymerization method, the mixing ratio of the solvent in the dropping solvent and the charged solvent can be set at an arbitrary ratio.
The amount of the charged solvent is not particularly limited and may be determined as appropriate. Usually, it is 30-700 mass parts with respect to 100 mass parts of whole quantity of a monomer component.

It is preferable to maintain the temperature of the monomer solution stored in the mixing tank 10 at 10 to 35 ° C. In addition, you may make it transfer the monomer solution prepared in the preparation tank 10 to another container (for example, storage tank etc.), and supply a monomer solution from this container to a polymerization tank. At this time, it is preferable to maintain the temperature of the monomer solution stored in another container at 10 to 35 ° C.
From the start of dropping to the end of dropping, the fluctuation range of the temperature of the monomer solution dropped into the polymerization tank (the temperature at the outlet of the supply pipe 16) is kept at 6 ° C. or less.
The temperature of the monomer solution is adjusted by a jacket provided in the preparation tank 10 or a heat exchanger 18 provided in the middle of the supply pipe 16 for supplying the monomer solution in the preparation tank 10 to the polymerization tank 20. Do.

The polymerization temperature is preferably 50 ° C. or higher, and preferably 150 ° C. or lower.
It is preferable to keep the fluctuation range of the polymerization temperature at 4 ° C. or less from the start of dropping of the monomer solution to the end of polymerization.
The polymerization temperature is adjusted by a jacket provided in the polymerization tank 20.
The polymerization time is preferably 1 hour or longer, and preferably 24 hours or shorter.

(C) Process:
The polymer solution in the polymerization tank 20 shown in FIG. 1 is diluted with a good solvent to an appropriate solution viscosity as necessary.
A poor solvent is injected into a purification tank 30 having a stirrer 32, a jacket (not shown) and a condenser 34. The polymer solution in the polymerization tank 20 is supplied to the purification tank 30 and dropped into a poor solvent while stirring with the stirrer 32 to precipitate the polymer to obtain a polymer dispersion.

Examples of the good solvent include the solvents used in the steps (a) to (b).
The poor solvent is a solvent having a small ability to dissolve the polymer, and the poor solvent varies depending on the composition of the polymer.
For example, “Polymer Handbook”, 4th edition, pages VII-497 to VII-545 describes nonsolvents corresponding to various polymers (Polymers).
When the polymer is an acrylic polymer for resist, the solubility parameter (hereinafter also simply referred to as “SP value”) has a value of 7.0 (cal / cm ³ ) ^{1/2 to} 9.0. (Cal / cm ³ ) ^1/2 [14.3 MPa ^{1/2 to} 18.5 MPa ^1/2 ], or 11.5 (cal / cm ³ ) ^{1/2 to} 23.4 (cal / cm ³ ) ^{1 / 2 A} solvent having a range of [23.5 MPa ^{1/2 to} 47.9 MPa ^1/2 ] is preferable as the poor solvent.
The SP value of the solvent can be determined, for example, by the method described in “Polymer Handbook”, 4th edition, pages VII-675 to VII-711. Specifically, Table 1 (VII- 683), Tables 7 to 8 (VII-688 to VII-711).
The SP value when the poor solvent is a mixed solvent of a plurality of solvents can be determined by a known method. For example, the SP value of the mixed solvent can be obtained as the sum of products of the SP value of each solvent and the volume fraction, assuming that additivity is established.
Examples of the poor solvent for the resist acrylic polymer include methanol, isopropanol, methyl-t-butyl ether, water, n-hexane, and n-heptane. A poor solvent may be used individually by 1 type, and may use 2 or more types together.
The amount of the poor solvent is preferably 300 to 3000 parts by mass with respect to 100 parts by mass of the polymer solution.

(D) Process:
The polymer dispersion liquid in the purification tank 30 shown in FIG. 1 is supplied to a vacuum filter 40 having a filter 42, and the polymer dispersion liquid is filtered using the filter 42 to recover the polymer powder.

Examples of the filter 42 include a filter cloth, a filter paper, a glass filter, a membrane filter, a cartridge filter, and a felt. Industrially, a filter cloth is preferable. The filter cloth is a cloth woven from long fibers. Examples of the long fiber material include synthetic resin (polyester, nylon, polypropylene, polytetrafluoroethylene, etc.), wool, cotton, ceramic, glass, cellulose, carbon, asbestos, metal (stainless steel, etc.), and the like. .
The filter 42 may be a filter obtained by washing the filter used in the previous lot, or may be a new filter that has never been used for filtration.

  Instead of the vacuum filter, a pressure filter, a gravity filter, a squeeze filter, a centrifuge, or the like may be used. Moreover, you may use 2 or more types together.

(E) Process:
A poor solvent is injected into the purification tank 30 shown in FIG. The polymer wet powder collected by the vacuum filter 40 is put into the refining tank 30 and stirred by the stirrer 32 and dispersed in a poor solvent to obtain a polymer dispersion.
As a poor solvent, the poor solvent used at the (c) process is mentioned.
The amount of the poor solvent is preferably 300 to 3000 parts by mass with respect to 100 parts by mass of the polymer wet powder.

(F) Process:
In the same manner as in the step (d), the polymer dispersion is filtered using the filter 42 to recover the polymer wet powder.
As the filter 42, the filter used in the step (d) may be used as it is, or another filter may be newly prepared and used instead of the filter used in the step (d).

(G) Process:
The polymer powder collected in the step (f) is transferred to a drier (not shown), and the damp powder is dried by the drier to obtain a powder product as a final product.
As for dryers, indirect heating method box drying device (vacuum), indirect heating method box drying device (freezing vacuum), indirect heating method stirring drying device (dish shape, round shape, groove shape), indirect heating method rotary drying Equipment, indirect superheated drum type dryer, direct superheated box type dryer (parallel, aerated, fluidized bed), direct heating type tunnel type dryer, direct heating type band type dryer (parallel, aerated), direct heating method Sheet dryer, direct superheat multi-stage disk dryer, direct superheater vertical turbo dryer, direct superheater vertical aeration dryer, direct superheat rotary dryer (direct, aeration), direct heating vibration dryer, Direct heating method fluidized drying device, direct heating method air flow drying device, direct heating method spray drying device, direct heating method foam layer drying device, infrared drying device, high frequency drying device, ultrasonic drying device etc. . As the dryer, an indirect heating type box-type dryer is preferable from the viewpoint of excellent sensitivity and resolution when used as a resist composition.
The drying temperature is preferably 20 to 100 ° C.
The drying time is preferably 2 to 200 hours.

(H) Process:
A good solvent is poured into a dissolution tank 50 having a stirrer 52, a jacket (not shown) and a condenser 54 shown in FIG. The polymer powder collected in the step (f) is charged into the dissolution tank 50 and stirred with a stirrer 52 and dissolved in a good solvent to obtain a polymer solution.
As a good solvent, the solvent for the below-mentioned resist composition is mentioned.
The amount of the good solvent is preferably 100 to 5000 parts by mass with respect to 100 parts by mass of the polymer.

(I) Process:
The polymer solution in the dissolution tank 50 shown in FIG. 1 is supplied to a microfilter 60 having a precision filter, and the polymer solution is passed through the precision filter to remove impurities.
Examples of the precision filter include a membrane filter and a cartridge filter.

(J) Process:
The polymer solution that has passed through the precision filter is poured into a concentration tank 70 having a stirrer 72, a jacket (not shown) and a condenser 74 shown in FIG. The polymer solution in the concentration tank 70 is heated with a jacket while being stirred with the stirrer 72, the poor solvent remaining from the polymer solution is removed under reduced pressure, and the polymer solution is further concentrated to a predetermined polymer concentration. Thus, a polymer solution as a final product is obtained.
The poor solvent and the vapor of the good solvent discharged from the concentration tank 70 are condensed into a liquid by the condenser 74 and sent to the recovery tank 80.

<Polymer, resist composition>
In the case of a resist polymer, the polymer obtained by the production method of the present invention preferably has a mass average molecular weight of 1000 or more, and preferably 1000000 or less. When the resist polymer is used in a positive resist composition, the mass average molecular weight of the resist polymer is preferably 1000 or more, more preferably 2000 or more, from the viewpoint of etching resistance and resist pattern shape. It is especially preferable that it is 5000 or more. In the case where the resist polymer is used as a positive resist composition, the mass average molecular weight of the resist polymer is preferably 100,000 or less, more preferably 50,000 or less, from the viewpoint of solubility in a solvent and resolution. Is more preferable, and it is especially preferable that it is 20000 or less.
The molecular weight distribution (Mw / Mn) of the polymer obtained by the production method of the present invention is not particularly limited. However, when used as a resist polymer, it is 2.5 from the viewpoint of solubility in a resist solution and resolution. The following is preferable, 2.3 or less is more preferable, and 2.0 or less is particularly preferable.

  The resist polymer is suitably used as a raw material for the resist composition. The resist composition is obtained by dissolving a resist polymer in a solvent. The chemically amplified resist composition is obtained by dissolving a resist polymer and a photoacid generator in a solvent. The resist polymer may be used alone or in combination of two or more. The resist composition may contain a polymer other than the resist polymer obtained by the production method of the present invention.

The solvent for the resist composition is arbitrarily selected according to use conditions and the like.
Examples of the solvent include linear or branched ketones such as methyl ethyl ketone, methyl isobutyl ketone, 2-pentanone and 2-hexanone; cyclic ketones such as cyclopentanone and cyclohexanone; propylene glycol monomethyl ether acetate, propylene glycol monoethyl Propylene glycol monoalkyl ether acetates such as ether acetate; Ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate; Propylene glycol monoalkyl such as propylene glycol monomethyl ether and propylene glycol monoethyl ether Ethers; ethylene glycol monomethyl ether, ethylene glycol Ethylene glycol monoalkyl ethers such as monoethyl ether; diethylene glycol alkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol monomethyl ether; esters such as ethyl acetate and ethyl lactate; n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexanol , Alcohols such as 1-octanol; 1,4-dioxane, ethylene carbonate, γ-butyrolactone; pentane, 2-methylbutane, n-hexane, 2-methylpentane, 2,2-dibutylbutane, 2,3-dibutylbutane , N-heptane, n-octane, isooctane, 2,2,3-trimethylpentane, n-nonane, 2,2,5-trimethylhexane, n-decane, n-dodecane, etc. 11 aliphatic hydrocarbon solvents and the like. A solvent may be used individually by 1 type and may use 2 or more types together.
As the solvent, propylene glycol monomethyl ether acetate, ethyl lactate, cyclohexanone, and γ-butyrolactone are preferable because they are highly safe and widely used.

  The concentration (solid content concentration) of the polymer in the resist composition (solution) is not particularly limited, but is preferably 50% by mass or less in the resist composition (100% by mass) from the viewpoint of the viscosity of the resist composition. The mass% or less is more preferable, and 30 mass% or less is more preferable. The concentration of the polymer in the resist composition is preferably 2% by mass or more, more preferably 5% by mass or more, and further preferably 8% by mass or more from the viewpoint of the resist film thickness.

When the resist polymer is used for a chemically amplified resist composition, it is necessary to use a photoacid generator.
The photoacid generator can be arbitrarily selected from those that can be used as the acid generator of the chemically amplified resist composition. A photo-acid generator may be used individually by 1 type, and may use 2 or more types together.

  Examples of the photoacid generator include onium salt compounds, sulfonimide compounds, sulfone compounds, sulfonic acid ester compounds, quinone diazide compounds, diazomethane compounds, and the like. Of these, the photoacid generator is preferably an onium salt compound such as a sulfulonium salt, iodonium salt, phosphonium salt, diazonium salt, pyridinium salt, specifically, triphenylsulfonium triflate, triphenylsulfonium hexafluoro. Antimonate, triphenylsulfonium naphthalenesulfonate, (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate, diphenyliodonium triflate, diphenyliodonium pyrenesulfonate, diphenyliodonium dodecylbenzenesulfonate, diphenyliodonium hexafluoroantimonate, p-methylphenyldiphenylsulfonium nonafluoro Butanesulfonate, tri (tert-butylphenyl) sulfonium Trifluoromethanesulfonate and the like.

  The amount of the photoacid generator is appropriately determined depending on the type of the photoacid generator selected, and is usually 0.1 parts by mass or more and 0.5 parts by mass or more with respect to 100 parts by mass of the resist polymer. More preferred. By setting the amount of the photoacid generator within this range, a chemical reaction due to the catalytic action of the acid generated by exposure can be sufficiently caused. Moreover, the quantity of a photo-acid generator is 20 mass parts or less normally with respect to 100 mass parts of resist polymers, and 10 mass parts or less are more preferable. By setting the amount of the photoacid generator within this range, the stability of the resist composition is improved, and the occurrence of uneven coating during application of the composition, scum during development, etc. is sufficiently reduced.

  Furthermore, a nitrogen-containing compound can also be mix | blended with a chemically amplified resist composition. By containing a nitrogen-containing compound, the resist pattern shape, the stability over time, and the like are further improved. In other words, the cross-sectional shape of the resist pattern is closer to a rectangle, and the resist film is exposed, post-exposure baked (PEB), and left for several hours before the next development process. Yes, the occurrence of deterioration of the cross-sectional shape of the resist pattern is further suppressed when left as such (timed).

Any known compounds can be used as the nitrogen-containing compound, and among these, amines are preferable, and secondary lower aliphatic amines and tertiary lower aliphatic amines are more preferable. The lower aliphatic amine means an alkyl or alkyl alcohol amine having 5 or less carbon atoms.
Examples of the secondary lower aliphatic amine and tertiary lower aliphatic amine include trimethylamine, diethylamine, triethylamine, di-n-propylamine, tri-n-propylamine, tripentylamine, diethanolamine, triethanolamine and the like. Is mentioned. Among these, as the nitrogen-containing compound, a tertiary alkanolamine such as triethanolamine is more preferable.
A nitrogen-containing compound may be used individually by 1 type, and may use 2 or more types together.

  The amount of the nitrogen-containing compound is appropriately determined depending on the type of the selected nitrogen-containing compound, and is usually preferably 0.01 parts by mass or more with respect to 100 parts by mass of the resist polymer. By making the amount of the nitrogen-containing compound within this range, the resist pattern shape can be made more rectangular. The amount of the nitrogen-containing compound is usually preferably 2 parts by mass or less with respect to 100 parts by mass of the resist polymer. By setting the amount of the nitrogen-containing compound within this range, deterioration in sensitivity can be reduced.

The chemically amplified resist composition may also contain an organic carboxylic acid, a phosphorus oxo acid, or a derivative thereof. By containing these compounds, it is possible to prevent sensitivity deterioration due to the compounding of the nitrogen-containing compound, and further improve the resist pattern shape, the stability with time of standing, and the like.
As the organic carboxylic acid, for example, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are preferable.
Phosphorus oxoacids or derivatives thereof include, for example, phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester and other phosphoric acid and derivatives thereof; phosphonic acid, phosphonic acid dimethyl ester Phosphonic acids such as phosphonic acid di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester, etc. and derivatives thereof; phosphinic acids such as phosphinic acid, phenylphosphinic acid and their Examples include derivatives such as esters. Of these, phosphonic acid is preferred.
These compounds (organic carboxylic acid, phosphorus oxo acid, or derivatives thereof) may be used alone or in combination of two or more.

  The amount of these compounds (organic carboxylic acid, phosphorus oxo acid, or derivative thereof) is appropriately determined depending on the type of the selected compound and the like, and is usually 0.01 mass per 100 mass parts of the resist polymer. Part or more is preferred. By setting the amount of these compounds within this range, the resist pattern shape can be made more rectangular. The amount of these compounds (organic carboxylic acid, phosphorus oxo acid, or derivative thereof) is usually preferably 5 parts by mass or less with respect to 100 parts by mass of the resist polymer. By reducing the amount of these compounds within this range, the film loss of the resist pattern can be reduced.

Both the nitrogen-containing compound and one or more selected from the group consisting of organic carboxylic acids, phosphorus oxo acids and derivatives thereof may be contained in the chemically amplified resist composition, or only one of them may be contained. May be.
Further, the resist composition may contain various additives such as surfactants, quenchers other than the nitrogen-containing compounds, sensitizers, antihalation agents, storage stabilizers, antifoaming agents, etc., as necessary. Also good. Any of these additives can be used as long as it is known in the art. Moreover, the addition amount of these additives is not specifically limited, What is necessary is just to determine suitably.

  The resist composition of the present invention may be used as a resist composition for metal etching, photofabrication, plate making, hologram, color filter, retardation film and the like.

A resist pattern can be formed using the resist composition of the present invention. An example of a method for forming a resist pattern using the resist composition will be described.
First, a resist composition is applied to the surface of a substrate to be processed such as a silicon wafer on which a pattern is formed by spin coating or the like. And the to-be-processed board | substrate with which this resist composition was apply | coated is dried by baking process (prebaking) etc., and a resist film is formed on a board | substrate.

Next, the resist film thus obtained is irradiated with light having a wavelength of 250 nm or less through a photomask (exposure). The light used for exposure is preferably a KrF excimer laser, an ArF excimer laser, or an F ₂ excimer laser, and particularly preferably an ArF excimer laser. Moreover, you may expose with an electron beam.

  After exposure, heat treatment is appropriately performed (post-exposure baking, PEB), the substrate is immersed in an alkaline developer, and the exposed portion is dissolved in the developer and removed (development). Any known alkaline developer may be used. Then, after development, the substrate is appropriately rinsed with pure water or the like. In this way, a resist pattern is formed on the substrate to be processed.

  In general, a substrate to be processed on which a resist pattern is formed is appropriately heat-treated (post-baked) to reinforce the resist pattern, and a portion without the resist pattern is selectively etched. After etching, the resist pattern is usually removed using a release agent.

  In the method for producing a polymer of the present invention described above, a monomer solution containing a monomer component and a polymerization initiator is dropped into a solvent maintained at a polymerization temperature in a polymerization tank, When polymerizing the body component, the fluctuation range of the temperature of the monomer solution dripped into the polymerization tank is kept at 6 ° C. or less, so that the fluctuation range of the polymerization temperature in the polymerization tank is reduced, and the molecular weight of the resulting polymer and The deviation of the molecular weight distribution from the target molecular weight and the molecular weight distribution is suppressed. As a result, it is possible to obtain a polymer that can exhibit the performance as designed in the intended application.

Moreover, since the polymer of this invention is a polymer obtained by the manufacturing method of this invention, it can exhibit the performance as designed in the intended use.
In addition, since the resist composition of the present invention contains the polymer obtained by the production method of the present invention, the resist film can exhibit the performance as designed and the occurrence of defects in the resist pattern can be suppressed.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Example 1]
(Manufacture of resist polymer)
(A) Process:
In a mixing tank having a stirrer and a jacket, monomer (1-1) (where R is a methyl group) 23.1 parts by mass, monomer (2-10) (where R is a methyl group) 26 0.7 parts by mass, monomer (3-4) (wherein R is a methyl group) 16.1 parts by mass, ethyl lactate 98.7 parts by mass, and dimethyl-2,2′-azo as a polymerization initiator 1.96 parts by mass of bisisobutyrate (manufactured by Wako Pure Chemical Industries, Ltd., V601 (trade name)) was injected and stirred to prepare a monomer solution.

(B) Process:
Under a nitrogen atmosphere, 54.9 parts by mass of ethyl lactate was poured into a polymerization tank having a nitrogen inlet, a stirrer, a jacket, and a condenser, and the temperature was maintained at 80 ° C. ± 1 ° C. while stirring. While maintaining the temperature of the monomer solution in the compounding tank at 25 ° C. ± 5 ° C. by the jacket of the compounding tank, the monomer solution was supplied to the polymerization tank, and the lactic acid maintained at 80 ° C. ± 1 ° C. by the jacket of the polymerization tank It was dripped in ethyl over 6 hours at a constant rate. From the start of dropping of the monomer solution to the end of dropping, the temperature of the monomer solution at the outlet of the supply pipe is 25 ° C. ± 1 ° C. by a heat exchanger provided in the supply pipe for supplying the monomer to the polymerization tank. Kept. Further, the temperature of the solution in the polymerization tank was controlled to 80 ° C. ± 2 ° C. by the jacket of the polymerization tank from the start of dropping of the monomer solution to the end of dropping. Thereafter, the solution in the polymerization tank was held at 80 ° C. ± 1 ° C. for 1 hour by the jacket of the polymerization tank to obtain a polymer solution.

(C) Process:
Into a purification tank having a stirrer, a jacket and a condenser, 1078 parts by mass of methanol and 340 parts by mass of water were injected. 220 parts by mass of the polymer solution in the polymerization tank was supplied to the purification tank and dropped into the mixed solvent of methanol and water while stirring to precipitate the polymer, thereby obtaining a polymer dispersion.

(D) Process:
The polymer dispersion in the purification tank is supplied to a vacuum filter having a filter (Miracle filter cloth (trade name) manufactured by Toray Industries, Inc.), and the polymer dispersion is filtered using the filter to obtain a polymer. Of wet powder was recovered.

(E) Process:
Into the purification tank, 1445 parts by mass of methanol and 255 parts by mass of water were injected. 140 parts by mass of the polymer wet powder collected by the vacuum filter was put into a purification tank, stirred with a stirrer and dispersed in a mixed solvent of methanol and water to obtain a polymer dispersion.

(F) Process:
The polymer dispersion liquid in the purification tank was supplied to a vacuum filter having a filter, and the polymer dispersion liquid was filtered using the filter to recover a polymer wet powder. As the filter, the filter used in the step (d) was used as it was without washing.

(H) Process:
490 parts by mass of propylene glycol monomethyl ether acetate was poured into a dissolution tank having a stirrer, a jacket and a condenser. (F) 140 parts by mass of the polymer wet powder recovered in the step was put into a dissolution tank, stirred with a stirrer and dissolved in propylene glycol monomethyl ether acetate to obtain a polymer solution.

(I) Process:
The polymer solution in the dissolution tank was supplied to a microfilter having a precision filter (P-NYLON N66FILTER 0.04M (trade name) manufactured by Nippon Pole Co., Ltd.), and the polymer solution was passed through the precision filter to remove impurities. .

(J) Process:
The polymer solution that passed through the precision filter was poured into a concentration tank having a stirrer, a jacket, and a condenser. The polymer solution in the concentration tank is heated with a jacket while stirring with a stirrer, and the remaining methanol and water are removed from the polymer solution under reduced pressure, and the polymer solution is further added until the polymer concentration reaches 25% by mass. Concentration gave a polymer solution.

(Weight average molecular weight, molecular weight distribution of polymer)
A part of the polymer solution was sampled, and the solvent was removed from the solution to obtain a solid polymer. About 20 mg of the polymer was dissolved in 5 mL of tetrahydrofuran and filtered through a membrane filter having a pore size of 0.5 μm to prepare a sample solution. This sample solution was introduced into a gel permeation chromatography (GPC) manufactured by Tosoh Corporation, and the mass average molecular weight (Mw) and the number average molecular weight (Mn) were measured. Moreover, molecular weight distribution (Mw / Mn) was calculated | required from the mass average molecular weight (Mw) and the number average molecular weight (Mn). The results are shown in Table 1.
As a separation column, a product made by Showa Denko Co., Ltd., made of three Shodex GPC K-805L (trade name) in series was used. As a solvent, tetrahydrofuran (flow rate: 1.0 mL / min) was used as a detector. Used a differential refractometer. The measurement conditions were a measurement temperature of 40 ° C. and an injection volume of 0.1 mL. Tosoh standard polystyrene F-80 (Mw = 706,000), F-20 (Mw = 190,000), F-4 (Mw = 37,900), F-1 (Mw = 10,200) as standard polymers , A-2500 (Mw = 2,630), A-500 (Mw = 682, 578, 474, 370, 260 mixture) (trade name) were used.

(Preparation of resist composition)
After mixing 400 parts by mass of a polymer solution (solid content 100.8 parts by mass), 400 parts by mass of propylene glycol monomethyl ether acetate and 2 parts by mass of triphenylsulfonium triflate as a photoacid generator, a uniform solution was obtained. The resist composition was prepared by filtering through a 0.1 μm membrane filter.

(Formation of resist pattern)
The resist composition was spin-coated on a silicon wafer and prebaked at 120 ° C. for 60 seconds using a hot plate to form a resist film having a thickness of 0.4 μm. Next, after exposure using an ArF excimer laser exposure machine (wavelength: 193 nm), post-exposure baking was performed using a hot plate at 120 ° C. for 60 seconds. Subsequently, it developed at room temperature using the 2.38 mass% tetramethylammonium hydroxide aqueous solution, wash | cleaned with the pure water, and dried, and the resist pattern was formed.

(sensitivity)
The exposure amount (mJ / cm ² ) for forming a line-and-space (L / S = 1/1) with a line width of 1/1 was measured and used as sensitivity. The results are shown in Table 1.

(resolution)
The minimum dimension (μm) of the resist pattern resolved when exposed at the exposure amount was defined as the resolution. The results are shown in Table 1.

(Resist pattern)
Resist patterns were observed with a JSM-6340F field emission scanning electron microscope (trade name) manufactured by JEOL, and those with no defects were evaluated as good and those with defects were evaluated as defective. The results are shown in Table 1.

[Example 2]
In the step (b), a polymer was produced in the same manner as in Example 1 except that the temperature of the monomer solution in the preparation tank was kept at 25 ° C. ± 10 ° C., and a resist composition was prepared and evaluated. It was. The evaluation results are shown in Table 1.

Example 3
(A) The monomer component used in the step is monomer (1-12) (where R is a hydrogen atom), 33.7 parts by mass, monomer (2-2) (where R is a methyl group) 37.7 parts by mass and monomer (3-7) (where R is a methyl group) 19.7 parts by mass; dripping solvent changed to 136.7 parts by mass of propylene glycol monomethyl ether acetate Change the charged solvent to a mixed solvent of 33.41 parts by mass of propylene glycol monomethyl ether acetate and 42.5 parts by mass of γ-butyrolactone; dimethyl-2,2′-azobisisobutyrate (sum of polymerization initiator) The amount of V601 (trade name) manufactured by Kojun Pharmaceutical Co., Ltd. was changed to 3.50 parts by mass; the poor solvent used in the step (b) was changed to 1824 parts by mass of methanol; the poor used in the step (d) Solvent for methanol Was changed to 824 parts by mass, to prepare to polymer in the same manner as in Example 1, a resist composition was prepared and evaluated. The evaluation results are shown in Table 1.

Example 4
In step (b), a polymer was produced in the same manner as in Example 3 except that the temperature of the monomer solution in the preparation tank was kept at 25 ° C. ± 10 ° C., and a resist composition was prepared and evaluated. It was. The evaluation results are shown in Table 1.

[Comparative Example 1]
In the step (b), a polymer is produced in the same manner as in Example 1 except that the temperature of the monomer solution in the preparation tank and the temperature of the polymer solution at the outlet of the supply pipe are not adjusted. Prepared and evaluated. The temperature of the monomer solution in the compounding tank varied between 3 ° C. and 10 ° C., and the temperature of the monomer solution at the outlet of the supply tube varied between 3 ° C. and 10 ° C. As a result, the polymerization tank temperature rapidly decreased to 75 ° C. until 10 minutes after the initial dropping, and the temperature of the solution in the polymerization tank became 80 ° C. ± 3 ° C. The evaluation results are shown in Table 1.

[Comparative Example 2]
In the step (b), a polymer is produced in the same manner as in Example 3 except that the temperature of the monomer solution in the preparation tank and the temperature of the polymer solution at the outlet of the supply pipe are not adjusted. Prepared and evaluated. The temperature of the monomer solution in the compounding tank varied between 3 ° C. and 10 ° C., and the temperature of the monomer solution at the outlet of the supply tube varied between 3 ° C. and 10 ° C. As a result, the polymerization tank temperature rapidly decreased to 75 ° C. until 10 minutes after the initial dropping, and the temperature of the solution in the polymerization tank became 80 ° C. ± 3 ° C. The evaluation results are shown in Table 1.

[Comparative Example 3]
In the step (b), a polymer was produced in the same manner as in Example 1 except that the temperature of the monomer solution in the preparation tank was not adjusted with a jacket, and a resist composition was prepared and evaluated. The temperature of the monomer solution in the mixing tank varied between 35 ° C. and 45 ° C., and the temperature of the monomer solution at the outlet of the supply pipe was kept at 25 ° C. ± 1 ° C. by a heat exchanger. The evaluation results are shown in Table 1.

[Comparative Example 4]
In step (b), a polymer was produced in the same manner as in Example 3 except that the temperature of the monomer solution in the preparation tank was not adjusted with a jacket, and a resist composition was prepared and evaluated. The temperature of the monomer solution in the mixing tank varied between 35 ° C. and 45 ° C., and the temperature of the monomer solution at the outlet of the supply pipe was kept at 25 ° C. ± 1 ° C. by a heat exchanger. The evaluation results are shown in Table 1.

The polymers of Examples 1 and 2 had little variation in molecular weight and molecular weight distribution. In the resist composition, it was confirmed that the performance (sensitivity and resolution) of the resist film was small and the performance as designed was exhibited. The resist pattern was also good. Similar results were obtained for the polymers and resist compositions of Examples 3 and 4.
On the other hand, the polymer of Comparative Example 1 has a molecular weight and molecular weight distribution greatly deviated from Examples 1 and 2, and the resist composition has a resist film performance greatly deviated from Examples 1 and 2, and the performance as designed. I couldn't show it. The polymer of Comparative Example 2 also has a molecular weight and molecular weight distribution largely different from those in Examples 3 and 4, and the resist composition also shows a performance as designed, with the resist film performance greatly deviating from Examples 3 and 4. could not. In Comparative Examples 3 and 4, the polymerization of the monomer solution started, and the molecular weight and molecular weight distribution deviated significantly from Examples 1 and 3.

  According to the method for producing a polymer of the present invention, a polymer and a resist composition capable of exhibiting performance as designed in an intended application can be produced, and a circuit formed using a resist pattern comprising the resist composition. Reduction in accuracy, yield, etc. can be suppressed.

10 Mixing tank 20 Polymerization tank

Claims (3)

A step of dropping a monomer solution containing a monomer component and a polymerization initiator stored in a container into a solvent maintained at a polymerization temperature in a polymerization tank to polymerize the monomer component ,
The polymerization initiator is dimethyl-2,2′-azobisisobutyrate,
Keep the temperature of the monomer solution in the container at 10 to 35 ° C.,
In addition, by adjusting the temperature of the monomer solution in the supply pipe that supplies the monomer solution in the container to the polymerization tank, the fluctuation range of the temperature of the monomer solution at the outlet of the supply pipe is set to 6 ° C. or less. Keep
And the manufacturing method of a polymer which keeps the fluctuation range of polymerization temperature at 4 degrees C or less. The method for producing a polymer according to claim 1, which is a method for producing a polymer for ArF excimer laser lithography. Method of manufacturing according to claim 1 or to produce a polymer by the method for producing a polymer according to 2, the obtained polymer, and a photoacid generator are dissolved in a solvent, the resist composition.

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