JP2008050482A - Method for producing polymer, polymer and resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer exhibiting designed performance in the objective use, a method for producing the polymer and a resist composition capable of giving a resist film exhibiting the designed performance and suppressing the generation of defects in a resist pattern. <P>SOLUTION: The polymer is produced by a production method including a step to polymerize a monomer component by a solution polymerization method to obtain a polymer solution and a step to cool the polymer solution with a cooling means (jacket 26) to ≤40°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

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 a monomer component is polymerized in a polymerization tank by dropping into a solvent maintained at a constant temperature.

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.

The method for producing a polymer of the present invention comprises a step of polymerizing monomer components by a solution polymerization method to obtain a polymer solution, and a step of cooling the polymer solution to 40 ° C. or lower using a cooling means. It is characterized by that.
In the polymer production method of the present invention, the polymer solution is preferably cooled to 40 ° C. within 60 minutes from the start of cooling.

The polymer of the present invention is obtained by the method for producing a polymer of the present invention.
The resist composition of the present invention is characterized by containing a polymer obtained by the method for producing a polymer of the present invention.

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.

  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>
The method for producing a polymer of the present invention includes a step of polymerizing a monomer component by a solution polymerization method to obtain a polymer solution, and a step of cooling the polymer solution to 40 ° C. or lower using a cooling means. Is the method.

  As the solution polymerization method, a so-called batch polymerization method (bulk polymerization method) in which a monomer solution containing a monomer component, a polymerization initiator, a solvent, etc. is charged in a polymerization tank and heated, a monomer component and A so-called dropping polymerization method in which a monomer solution containing a polymerization initiator and, if necessary, a solvent or the like is dropped into a solvent maintained at a constant temperature in a polymerization tank is exemplified.

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.
The polymerization temperature is preferably 50 ° C. or higher, and preferably 150 ° C. or lower.
The polymerization time is preferably 1 hour or longer, and preferably 24 hours or shorter.

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. A polymer, a fluorine-type polymer, etc. are mentioned.
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 polymer solution obtained by the solution polymerization method is forcibly cooled from the polymerization temperature to 40 ° C. or lower (preferably 30 ° C. or lower) using a cooling means. Cooling starts immediately after completion of the previous step, that is, after the polymerization time has elapsed. From the viewpoint of obtaining a polymer with almost no deviation from the target molecular weight and molecular weight distribution, it is preferable that the polymer solution is cooled to 40 ° C. within 60 minutes from the start of cooling, and the polymer solution is cooled to 60 minutes from the start of cooling. It is more preferable to cool to 30 ° C within 40 minutes, particularly preferably to 40 ° C within 40 minutes, and most preferably to 30 ° C within 30 minutes.
Examples of the cooling means include a jacket provided in the polymerization tank.

  In the present invention, the polymer solution obtained by the solution polymerization method is forcibly cooled to 40 ° C. or lower by using a cooling means, thereby causing the resist film to perform as designed and generating defects in the resist pattern. It is possible to produce a polymer capable of suppressing the above. 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, when the molecular weight of the obtained polymer is large and the molecular weight distribution is wide compared to 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, the present inventors conducted a study 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. As a result, when the polymer solution obtained by the solution polymerization method is naturally cooled, While the polymer solution is slowly cooled as shown by the dotted line in FIG. 1, the polymerization further proceeds in the polymer solution, and the molecular weight of the resulting polymer is smaller than the target molecular weight and molecular weight distribution. It has been found that the molecular weight distribution is large and wide. Therefore, as shown by the solid line in FIG. 1, the polymer solution obtained by the solution polymerization method is forcibly cooled to a temperature at which polymerization hardly occurs, that is, 40 ° C. or less, using a cooling means.
This problem, that is, the problem of further polymerization in the process of slowly cooling the polymer solution, becomes more prominent as the polymerization production scale increases. In particular, when solution polymerization is performed using a polymerization tank having an internal volume of 5 liters or more, if the polymer solution is cooled by natural cooling without using forced cooling means after the polymerization time has elapsed, the cooling rate is reduced. It becomes slow, and deviation from the target molecular weight and molecular weight distribution occurs.
Therefore, the method for producing a polymer of the present invention is preferable when solution polymerization is performed using a polymerization tank having an internal volume of 5 liters or more, and solution polymerization may be performed using a polymerization tank having an internal volume of 10 liters or more. More preferably, the case where solution polymerization is performed using a polymerization tank having an internal volume of 20 liters or more is particularly preferable. The upper limit of the internal volume of the polymerization tank is not particularly limited, but is preferably 100 m ³ or less.

  In addition, in polymers other than resist polymers, the target molecular weight and molecular weight distribution can be obtained by forcibly cooling the polymer solution obtained by the solution polymerization method to 40 ° C. or lower using a cooling means. In comparison with the above, it is possible to suppress the resulting polymer from having a large molecular weight and a broad molecular weight distribution, and to obtain a polymer that can exhibit the performance as designed in the intended application.

(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.
(B) A step of polymerizing monomer components by a solution polymerization method to obtain a polymer solution.
(C) The process of cooling a polymer solution to 40 degrees C or less using a cooling means.
(D) A step of pouring the polymer solution into a poor solvent in the container to precipitate the polymer to obtain a polymer dispersion.
(E) A step of recovering the polymer by filtering the polymer dispersion using a filter.
(F) A step of dispersing the recovered polymer in a poor solvent to obtain a polymer dispersion.
(G) A step of recovering the polymer by filtering the polymer dispersion using a filter.

The recovered polymer becomes a final product through (h) a step of drying the recovered polymer to obtain a powder product, or the following steps.
(I) A step of dissolving the recovered polymer in a good solvent to obtain a polymer solution.
(J) A step of removing impurities by passing the polymer solution through a precision filter.
(K) 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:
The method for preparing the monomer solution differs depending on the solution polymerization method in step (b).
Among the solution polymerization methods, the monomer component was heated to a predetermined polymerization temperature from the standpoint of easily obtaining a reproducible polymer with small variations in average molecular weight and molecular weight distribution due to differences in production lots. A polymerization method called a dropping polymerization method in which the polymerization vessel is dropped into a polymerization vessel is preferable.

The monomer component may be dropped only with the monomer component, or the monomer component may be dropped after being dissolved in an organic solvent (hereinafter also referred to as “dropping solvent”).
An organic solvent (hereinafter also referred to as “charged solvent”) may be charged into the polymerization vessel in advance, or the charged solvent may not be charged into the polymerization vessel in advance. In this case, the monomer component or the polymerization initiator is dropped into the polymerization vessel in the absence of the charged solvent.
The polymerization initiator may be dissolved in the monomer component or may be dissolved in the dropping solvent.
The monomer component and the polymerization initiator may be mixed in the same storage tank and then dropped into the polymerization container; they may be dropped into the polymerization container from independent storage tanks; They may be mixed immediately before being supplied to and dropped into the polymerization vessel.
One of the monomer component and the polymerization initiator may be dropped first, and then the other may be dropped with a delay, or both may be dropped at the same timing.
The dropping rate may be constant until the end of dropping, or may be changed in multiple stages according to the consumption rate of the monomer or the polymerization initiator.
The dripping may be performed continuously or intermittently.

Hereinafter, the case where the monomer component is polymerized by the dropping polymerization method in the step (b) will be described.
A raw material (a monomer component, a polymerization initiator, a solvent, etc.) is poured into a blending tank 10 having a stirrer 12 and a jacket 16 shown in FIG. 2, and stirred with the stirrer 12 to prepare a monomer solution.

  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-eliminable group include known monomers used in 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 the solvent, when a monomer component, a polymerization initiator, a polymer to be obtained, and a chain transfer agent are used in combination, a solvent that can dissolve all of the chain transfer agent 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.

In the step (a), a chain transfer agent may be used 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:
A solvent is poured into the polymerization tank 20 having the stirrer 22, the jacket 26, and the condenser 24 shown in FIG. 2 and maintained at a constant temperature. The monomer solution in the blending tank 10 is supplied to the polymerization tank 20 and dropped into a solvent maintained at a constant temperature to polymerize the monomer components to obtain a polymer solution.

Examples of the solvent include the solvent used in step (a).
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.
Although the monomer density | concentration of the monomer solution in the mixing tank 20 is not specifically limited, 5-50 mass% is preferable.
The amount of the charged solvent is not particularly limited and may be determined as appropriate.

The polymerization temperature is preferably 50 ° C. or higher, and preferably 150 ° C. or lower.
The polymerization time is preferably 1 hour or longer, and preferably 24 hours or shorter.

(C) Process:
(B) Immediately after the end of the process, cold water is allowed to flow through the jacket 26 provided in the polymerization tank 20 to forcibly cool the polymer solution from the polymerization temperature to 40 ° C. or less (preferably 30 ° C. or less). At this time, the polymer solution is preferably cooled to 40 ° C within 60 minutes from the start of cooling, more preferably the polymer solution is cooled to 30 ° C within 60 minutes from the start of cooling, and 30 ° C within 40 minutes. It is particularly preferable to cool to 30 ° C, and most preferably to 30 ° C within 30 minutes.

(D) Process:
The polymer solution cooled to 40 ° C. or lower is diluted to a suitable solution viscosity with a good solvent, if necessary.
A poor solvent is injected into a purification tank 30 having a stirrer 32, a condenser 34 and a jacket 36 shown in FIG. 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.

(E) Process:
The polymer dispersion liquid in the purification tank 30 shown in FIG. 2 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 resins (polyester, nylon, polypropylene, polytetrafluoroethylene, etc.), wool, cotton, ceramic, glass, cellulose, carbon, asbestos, and metals (stainless steel, etc.).
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.

(F) 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 (d) 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.

(G) Process:
In the same manner as in the step (e), 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 (e) may be used as it is, or another filter may be newly prepared and used instead of the filter used in the step (e).

(H) Process:
(G) The polymer powder collected in the step 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.

(I) Process:
A good solvent is poured into a dissolution tank 50 having a stirrer 52, a condenser 54 and a jacket 56 shown in FIG. The polymer wet powder recovered in the step (g) 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.

(J) Process:
The polymer solution in the dissolution tank 50 shown in FIG. 2 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.

(K) Process:
The polymer solution that has passed through the precision filter is poured into a concentration tank 70 having a stirrer 72, a jacket 76, and a condenser 74 shown in FIG. The polymer solution in the concentration tank 70 is heated by the jacket 76 while being stirred by the stirrer 72, the remaining poor solvent is removed from the polymer solution, and the polymer solution is further concentrated to a predetermined polymer concentration. A final polymer solution 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 and the like; derivatives such as phosphinic acid, phenylphosphinic acid and the like 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 the polymer of the present invention described above, the monomer component is polymerized by a solution polymerization method to obtain a polymer solution, and then the polymer solution is cooled to 40 ° C. or lower using a cooling means. Since cooling is performed, the progress of polymerization during cooling is suppressed, and deviations in the molecular weight and molecular weight distribution of the obtained polymer are suppressed from the target molecular weight and molecular weight distribution. 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 20 liter mixing tank having a stirrer and a jacket, 2.3 kg of monomer (1-1) (where R is a methyl group) and monomer (2-10) (where R is a methyl group) 2.7 kg, monomer (3-4) (where R is a methyl group) 1.6 kg, ethyl lactate 9.9 kg, and polymerization initiator dimethyl-2,2′-azobisisobutyrate ( 196 g of V601 (trade name) manufactured by Wako Pure Chemical Industries, Ltd. was injected and stirred to prepare a monomer solution.

(B) Process:
Under a nitrogen atmosphere, 5.5 kg of ethyl lactate was poured into a 30 liter polymerization tank having a nitrogen inlet, a stirrer, a jacket and a condenser, and the temperature was maintained at 80 ° C. while stirring. The monomer solution in the preparation tank was supplied to the polymerization tank and dropped into ethyl lactate maintained at 80 ° C. at a constant rate over 6 hours. Thereafter, the solution was kept at 80 ° C. for 1 hour to obtain a polymer solution.

(C) Process:
(B) Immediately after the completion of the step, 10 ° C. cold water was allowed to flow through the jacket provided in the polymerization tank to forcibly cool the polymer solution from 80 ° C. to 30 ° C. Specifically, the polymer solution at 80 ° C. was cooled to 30 ° C. in 30 minutes from the start of cooling.

(D) Process:
Methanol 108 kg and water 34 kg were injected into a 200 liter purification tank with stirrer, condenser and jacket. 22 kg of the polymer solution cooled in the polymerization tank was supplied to the purification tank and dropped into the mixed solvent of methanol and water with stirring to precipitate the polymer, thereby obtaining a polymer dispersion.

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

(F) Process:
145 kg of methanol and 26 kg of water were injected into the purification tank. 14 kg of the polymer wet powder recovered 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.

(G) 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.

(I) Process:
49 kg of propylene glycol monomethyl ether acetate was poured into a 100 liter dissolution tank with stirrer, condenser and jacket. (G) 14 kg of the polymer powder collected 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.

(J) 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. .

(K) Process:
The polymer solution that passed through the precision filter was poured into a 100 liter 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 to remove residual methanol and water from the polymer solution, and the polymer solution is further concentrated until the polymer concentration becomes 25% by mass, A polymer solution was obtained.

(Weight average molecular weight, molecular weight distribution of 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 polymer solution (100 parts by mass of solid content), 400 parts by mass of propylene glycol monomethyl ether acetate, and 2 parts by mass of triphenylsulfonium triflate as a photoacid generator, The mixture was filtered through a membrane filter having a pore size of 0.1 μm to prepare a resist composition.

(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 step (c), 20 ° C. cold water was passed through the jacket provided in the polymerization tank, and the 80 ° C. polymer solution was cooled to 40 ° C. in 60 minutes from the start of cooling. A coalescence was produced, a resist composition was prepared and evaluated. The evaluation results are shown in Table 1.

Example 3
Monomer component is monomer (1-12) (where R is a hydrogen atom) 3.4 kg, monomer (2-2) (where R is a methyl group) 3.8 kg, single amount Form (3-7) (where R is a methyl group) 2.0 kg; the dropping solvent is changed to 13.7 kg of propylene glycol monomethyl ether acetate; the charged solvent is 3.3 kg of propylene glycol monomethyl ether acetate and γ -Change to 4.3 kg mixed solvent of butyrolactone; the amount of dimethyl-2,2'-azobisisobutyrate (Vako Pure Chemical Industries, Ltd., V601 (trade name)) as a polymerization initiator to 350 g The polymer was produced in the same manner as in Example 1 except that the poor solvent used in step (e) was changed to 182 kg of methanol; and the poor solvent used in step (g) was changed to 182 kg of methanol. The resist composition was prepared and evaluated. The evaluation results are shown in Table 1.

Example 4
(C) In the step, heavy water was passed in the same manner as in Example 3 except that 20 ° C. cold water was allowed to flow through the jacket provided in the polymerization tank and the 80 ° C. polymer solution was cooled to 40 ° C. in 60 minutes from the start of cooling. A coalescence was produced, a resist composition was prepared and evaluated. The evaluation results are shown in Table 1.

[Comparative Example 1]
In step (c), a polymer was produced in the same manner as in Example 1 except that the polymer solution was naturally cooled (cooled) without flowing cold water through a jacket provided in the polymerization tank, and a resist composition was produced. Were prepared and evaluated. The evaluation results are shown in Table 1.

[Comparative Example 2]
In step (c), a polymer was produced in the same manner as in Example 3 except that the polymer solution was naturally cooled (cooled) without flowing cold water through a jacket provided in the polymerization tank, and a resist composition was produced. Were prepared and evaluated. 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.

  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.

It is a graph which shows the temperature change of the solution in the polymerization tank in a (b) process and a (c) process. It is a block diagram which shows an example of the manufacturing equipment of a polymer.

Explanation of symbols

26 Jacket (cooling means)

Claims (4)

A step of polymerizing monomer components by a solution polymerization method to obtain a polymer solution;
And cooling the polymer solution to 40 ° C. or lower using a cooling means.   The method for producing a polymer according to claim 1, wherein the polymer solution is cooled to 40 ° C within 60 minutes from the start of cooling.   A polymer obtained by the production method according to claim 1. A resist composition containing the polymer obtained by the production method according to claim 1.

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