JP2016079309A - Production method of polymer, production method of resist composition and method for manufacturing patterned substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a polymer in which amounts of a residual monomer and a residual solvent are more stabilized.SOLUTION: The production method of a polymer includes: a polymerization step of radically polymerizing a monomer by using a polymerization initiator in the presence of a polymerization solvent to obtain a polymerization reaction solution; and a purification step of mixing the polymerization reaction solution with a poor solvent of the polymer to precipitate the polymer, heating the slurry of the precipitated polymer and the solvent, and then cooling to a temperature lower by 5°C or more within 120 minutes and collecting the precipitate. By the method, 10 kg or more of the polymer per one batch is produced.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a polymer, a method for producing a resist composition using a polymer obtained by the production method, and a method for producing a substrate on which a pattern is formed using the resist composition.

  In recent years, a resist pattern formed in a manufacturing process of a semiconductor element, a liquid crystal element, or the like has been rapidly miniaturized due to progress in lithography technology. As a technique for miniaturization, there is a reduction in wavelength of irradiation light. Specifically, the irradiation light has become shorter from conventional ultraviolet rays typified by g-line (wavelength: 438 nm) and i-line (wavelength: 365 nm) to shorter wavelength DUV (Deep Ultra Violet). .

  Recently, KrF excimer laser (wavelength: 248 nm) lithography technology has been introduced, and ArF excimer laser (wavelength: 193 nm) lithography technology and EUV (wavelength: 13.5 nm) lithography technology for further shortening the wavelength have been studied. . Furthermore, these immersion lithography techniques are also being studied. Also, as a different type of lithography technology, electron beam lithography technology has been energetically studied.

The polymer is usually produced by a method in which a monomer is polymerized in the presence of a polymerization solvent to obtain a polymerization reaction solution containing the target polymer. In the polymerization reaction solution obtained, in addition to the target polymer, unnecessary components such as unreacted monomers are dissolved in the polymerization solvent. To remove these, the polymerization reaction solution is used as a poor solvent. There is known a method of refining using a reprecipitation method in which a polymer is precipitated by mixing with a liquid and then solid-liquid separated.
Patent Document 1 describes a method of solid-liquid separation after adding a polymerization reaction solution to a poor solvent to precipitate a polymer and then heating the slurry.
Patent Document 2 describes a method of solid-liquid separation after adding a polymerization reaction solution to a poor solvent to precipitate a polymer and then cooling the slurry.

JP 2002-201210 A JP 2009-138083 A

However, the conventional method is not necessarily sufficient in terms of stabilizing the lot-to-lot performance of the polymer required as the resist pattern becomes finer, and the amount of poor solvent and monomer remaining in the polymer is stabilized. It is desirable to produce a polymer that maintains the same value and exhibits the same performance.
The present invention has been made in view of the above circumstances. A method for producing a polymer in which the residual amount of an unreacted monomer or a poor solvent used in a purification process is stabilized, and a polymer obtained by the production method are as follows. An object of the present invention is to provide a method for producing a resist composition using the resist composition, and a method for producing a substrate on which a pattern is formed using the resist composition.

The above problems are solved by the present inventions [1] to [4] below.
[1] A polymerization step in which a polymerization initiator is used to radically polymerize a monomer in the presence of a polymerization solvent to obtain a polymerization reaction solution, and the polymerization reaction solution is mixed with a poor solvent for the polymer. And heating the precipitated polymer and solvent slurry, followed by a purification step in which the precipitate is recovered by cooling at 5 ° C. or higher within 120 minutes to produce 10 kg or more of polymer per batch. Manufacturing method of coalescence.

[2] The method for producing the polymer, wherein the step of precipitating the polymer is performed using a 1000 L or more container equipped with heat exchange equipment.
[3] A method for producing a resist composition, comprising mixing a polymer obtained by the method for producing a polymer and a compound capable of generating an acid upon irradiation with actinic rays or radiation.

[4] A step of applying a resist composition obtained by the above-described method for producing a resist composition on a processed surface of a substrate to form a resist film, a step of exposing the resist film, and an exposure step And a step of developing the resist film using a developing solution.

  According to the present invention, a polymer having a more stable residual monomer and residual solvent amount can be obtained. The performance of such a polymer is further stabilized, and resist performance such as sensitivity can be stabilized by preparing a resist composition using the polymer. Moreover, a highly accurate fine resist pattern can be formed more stably by producing a substrate on which a pattern is formed using the resist composition.

In the present specification, the “structural unit” means the largest molecular chain formed from one monomer molecule.
In the present specification, “(meth) acrylic acid” means acrylic acid or methacrylic acid, and “(meth) acryloyloxy” means acryloyloxy or methacryloyloxy.

<Method for producing polymer>
The method for producing a polymer of the present invention comprises a polymerization step in which a polymerization initiator is used to radically polymerize a monomer in the presence of a polymerization solvent to obtain a polymerization reaction solution, and the polymerization reaction solution is applied to the polymer. A polymer is precipitated by mixing with a poor solvent, and after the precipitated polymer and solvent slurry is heated, it has a purification step in which the precipitate is recovered by cooling at 5 ° C. or more within 120 minutes, and 10 kg or more per batch To produce a polymer.

<Polymerization process>
A solution polymerization method is used as the polymerization method. That is, a monomer is polymerized in the presence of a polymerization solvent to obtain a polymerization reaction solution. The solution polymerization method can be performed using a known method.
Preferably, a monomer is radically polymerized using a polymerization initiator in the presence of a polymerization solvent to obtain a polymerization reaction solution. The supply of the monomer and the polymerization initiator to the polymerization vessel may be a continuous supply or a drop supply. A drop polymerization method in which a monomer and a polymerization initiator are dropped into a polymerization vessel is preferred because variations in average molecular weight and molecular weight distribution due to differences in production lots are small and a reproducible polymer can be easily obtained.

In the dropping polymerization method, the inside of the polymerization vessel is heated to a predetermined polymerization temperature, and then the monomer and the polymerization initiator are dropped into the polymerization vessel independently or in any combination.
A monomer may be dripped only with a monomer, and may be dripped as a monomer solution which melt | dissolved the monomer in the polymerization solvent.
A polymerization solvent and / or monomer may be charged into the polymerization vessel in advance.
The polymerization initiator may be dissolved directly in the monomer, may be dissolved in the monomer solution, or may be dissolved only in the polymerization solvent.
The monomer and the polymerization initiator may be dropped into the polymerization vessel after mixing in the same storage tank; they may be dropped into the polymerization container from each independent storage tank; They may be mixed immediately before the supply and dropped into the polymerization vessel.
One of the monomer 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 speed may be constant until the dropping is completed, and may be changed in multiple stages depending on the copolymerization reactivity of the monomer and the consumption speed of the monomer or the polymerization initiator.
The dripping may be performed continuously or intermittently.
The polymerization temperature is preferably 50 to 150 ° C.
After a polymerization reaction at a predetermined polymerization temperature for a predetermined time, the polymerization reaction is stopped to obtain a polymerization reaction solution. As a method for stopping the polymerization reaction, a process of cooling the reaction solution is generally used, but it can also be stopped by adding a radical scavenger.

Examples of the polymerization solvent include the following.
Ethers: chain ether (diethyl ether, propylene glycol monomethyl ether, etc.), cyclic ether (tetrahydrofuran (hereinafter referred to as “THF”), 1,4-dioxane, etc.) and the like.
Esters: methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, propylene glycol monomethyl ether acetate (hereinafter referred to as “PGMEA”), γ-butyrolactone, and the like.
Ketones: acetone, methyl ethyl ketone (hereinafter referred to as “MEK”), methyl isobutyl ketone (hereinafter referred to as “MIBK”), cyclohexanone, and the like.
Amides: N, N-dimethylacetamide, N, N-dimethylformamide and the like.
Sulfoxides: dimethyl sulfoxide and the like.
Aromatic hydrocarbons: benzene, toluene, xylene and the like.
Aliphatic hydrocarbon: hexane and the like.
Alicyclic hydrocarbons: cyclohexane and the like.
A polymerization solvent may be used individually by 1 type, and may use 2 or more types together.

  As the polymerization initiator, those that generate radicals efficiently by heat are preferable. For example, an azo compound (2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] Etc.), organic peroxides (2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane, di (4-tert-butylcyclohexyl) peroxydicarbonate, etc.) and the like.

<Purification process>
In the purification step of the present invention, the polymerization reaction solution obtained in the above polymerization step is mixed with a poor solvent for the polymer to precipitate the polymer, and the precipitated polymer and solvent slurry is heated within 120 minutes. It includes a step of recovering precipitates by cooling at 5 ° C. or higher.
Specifically, the polymer in the polymerization reaction solution obtained in the polymerization step is purified using a reprecipitation method to obtain a purified polymer wet powder.
The reprecipitation method is a method in which a polymer is precipitated by mixing a poor solvent for a target polymer and a polymerization reaction solution, and then solid-liquid separation is performed to obtain a precipitate as a wet powder. This method is effective as a method for removing unreacted monomers, polymerization initiators and the like together with the polymerization solvent in the polymerization reaction solution. If unreacted monomer remains in the wet powder of the purified polymer, the sensitivity of the resist composition prepared using the wet powder tends to decrease. Therefore, it is preferable to remove as much as possible in the initial design stage.
The purification step includes at least a reprecipitation step in which a polymerization reaction solution is mixed with a poor solvent to precipitate a target lithography polymer and a wet powder is obtained by solid-liquid separation.
Further, after the solid-liquid separated wet powder is brought into contact with a rinsing solvent comprising a poor solvent, the rinsing step is performed to remove the rinse solvent to obtain the wet powder, and the solid-liquid separated wet powder or post-rinse It is preferable to carry out one or both of the steps of the slurrying step of obtaining the wet powder by solid-liquid separation after the wet powder is mixed with the poor solvent for the target polymer.

[Reprecipitation process]
In the reprecipitation step, the polymerization reaction solution obtained in the polymerization step is first mixed with a poor solvent to precipitate the polymer to be obtained.
The poor solvent is a solvent that has a small ability to dissolve the target lithography polymer and from which the polymer can precipitate. According to the composition of the polymer, known ones can be appropriately selected and used. Preferred poor solvents include methanol, isopropyl alcohol, diisopropyl ether, heptane, or water in that unreacted monomers, polymerization initiators, and the like used in the synthesis of the lithography polymer can be efficiently removed. . As the poor solvent, one kind of poor solvent may be used, or two or more kinds of solvents may be mixed and used. When a mixture of two or more solvents is used as a poor solvent, the mixture may be a poor solvent for the polymer, and the mixture may contain a good solvent that dissolves the polymer.

  When the polymerization reaction solution is mixed with the poor solvent in the reprecipitation step, the polymerization reaction solution is preferably dropped into the poor solvent to precipitate the polymer in the polymerization reaction solution. The mixing is preferably performed with stirring from the viewpoint that a uniform slurry can be formed. The amount of the poor solvent used is not particularly limited, but is preferably the same mass or more as the polymerization reaction solution, more preferably 3 times or more, and more preferably 4 times or more, in terms of easier reduction of unreacted monomers. 5 times or more is more preferable, and 6 times or more is particularly preferable. The upper limit is not particularly limited, but if it is too much, the working efficiency in the subsequent solid-liquid separation step is deteriorated. For example, 10 times or less is preferable on a mass basis.

Before mixing the polymerization reaction solution with the poor solvent, the polymerization reaction solution may be diluted to an appropriate solution viscosity with a diluent solvent, if necessary. Examples of the diluent solvent include 1,4-dioxane, acetone, THF, MEK, MIBK, γ-butyrolactone, PGMEA, PGME, ethyl lactate, and ethyl acetate. These may use 1 type and may use 2 or more types together.
When performing dilution, the difference between the solubility parameter (hereinafter also referred to as SP value) of the solvent (mixture of polymerization solvent and dilution solvent) in the diluted polymerization reaction solution and the SP value of the poor solvent used for reprecipitation is The smaller one is preferable in that good dispersibility of the polymer can be obtained and the monomer can be efficiently removed.
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). Further, the SP value in 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.

  When mixing the polymerization reaction solution with a poor solvent in the reprecipitation step, it is preferable to maintain the polymerization reaction solution at a constant temperature in terms of stabilizing the performance between lots, and it is more preferable to control it within 10 ° C. from the set temperature. . Similarly, the temperature of the poor solvent is preferably maintained at a constant temperature, and more preferably controlled within 10 ° C. from the set temperature. It is preferable that the temperature difference between the polymerization reaction solution and the poor solvent is within 15 ° C, more preferably within 10 ° C, more preferably within 5 ° C, in terms of good temperature controllability and stabilization of performance between lots. More preferably.

The slurry obtained by mixing the polymerization reaction solution and the poor solvent is heated. It is preferable to heat at 5 ° C. or higher, more preferably 10 ° C. or higher, and more preferably 15 ° C. or higher in terms of easier reduction of unreacted monomers and good liquid removal efficiency in the subsequent solid-liquid separation step. More preferably. The upper limit of the heating temperature is not particularly limited, but is preferably not higher than the boiling point of the poor solvent in that a stable slurry state can be maintained. Moreover, 65 degrees C or less is preferable at the point which can maintain a slurry state, without a polymer fuse | melting, 60 degrees C or less is more preferable, and 55 degrees C or less is further more preferable.
Heating is preferably performed with stirring from the viewpoint that a uniform slurry state can be maintained.
The heated slurry can be held at that temperature for a certain time. The longer the holding time is, the easier it is to reduce the unreacted monomer for 5 minutes or more, 10 minutes or more is more preferable, 15 minutes or more is more preferable, and 20 minutes or more is particularly preferable. The holding time is preferably 120 minutes or less from the viewpoint that the process time does not become too long and the production efficiency is excellent.

In the method for producing a polymer of the present invention, the heated slurry is cooled to 5 ° C. or more within 120 minutes, and then a polymer precipitated in a subsequent recovery step is obtained. In the state where the slurry is heated, the remaining amount of the unreacted monomer changes depending on the time during which the state is maintained. Accordingly, the performance between lots of polymers obtained by forcibly cooling the slurry at a certain cooling rate or more is stabilized. The cooling rate may be 5 ° C. or more within 120 minutes, preferably 5 ° C. or more within 90 minutes, and more preferably 5 ° C. or more within 60 minutes in terms of efficient production. Preferably, it is more preferably cooled at 5 ° C. or more within 30 minutes.
In the present specification, “cooling the heated slurry at 5 ° C. or more within 120 minutes” means that the slurry is heated and / or held and then at 5 ° C. or more within 120 minutes from the start of the cooling operation. Means cooling.

The polymer production method of the present invention is a scaled-up batch production method for producing a polymer of 10 kg or more per batch, and the operation of depositing the polymer to form a slurry is performed using a 1000 L or more container. Can be suitably used.
As the scale becomes larger, the responsiveness of the temperature control becomes worse. However, it is preferable to form the slurry in a vessel equipped with a heat exchange facility in that the temperature of the slurry can be controlled efficiently. As long as the heat exchange equipment is a tube format, it can be a coil type single tube type, double tube type, multi-tube type (fixed tube plate type, floating head type, U-tube type), etc. For example, a plate type, a spiral type, and a jacket type can be mentioned. By using a container equipped with a heat exchange facility, the effects of the present invention can be achieved even when producing a polymer of 20 kg or more per batch, which has a larger scale, and more than 30 kg of polymer per batch. Even in the case of manufacturing, it is possible to obtain more effects.
In order to cool the slurry in a vessel of 1000 L or more within 5 minutes at 120 ° C., it is preferable to use a refrigerant that has cooled the liquid in the heat exchange facility. The temperature of the refrigerant is preferably 30 ° C. or less, more preferably 25 ° C. or less, still more preferably 20 ° C. or less, and particularly preferably 15 ° C. or less in terms of efficient production. The temperature of the refrigerant is preferably maintained at a constant temperature from the viewpoint of stabilizing the performance between lots, and more preferably controlled within 10 ° C. from the set temperature.
The container for forming the slurry is preferably a metal container in terms of excellent thermal conductivity and easy temperature control. As the metal, stainless steel (hereinafter also referred to as SUS) is preferable because it has high corrosion resistance and can easily reduce the mixing of metal impurities into the polymer. Of the inner surface of the container, it is preferable that at least a portion in contact with the slurry is made of stainless steel.

[Recovery process]
By subjecting the precipitate in the poor solvent to solid-liquid separation, the target polymer is obtained in the form of a wet powder. In the initial design stage, the lower the monomer content in the polymer, the better. In the production after the second lot, it is preferable that the monomer content is equal to that of the initial lot in order to stabilize the performance between lots.
The solid-liquid separation operation can be performed by a known method using a solid-liquid separator such as a pressure filter, a vacuum filter, a natural filter, or a centrifuge.
As a method of increasing the solid content of the wet powder obtained in the reprecipitation step, perform solid-liquid separation using a pressure filter, vacuum filter, or centrifuge so that the amount of liquid removal increases. A method of adjusting operating conditions such as pressure, centrifugal force and operating time is preferred.
For example, if a centrifugal separator is used, the centrifugal force applied to the polymer is increased, if a vacuum filter is used, the suction pressure is increased, and if a pressure filter is used, the pressure is increased. The amount of liquid can be increased.
In particular, it is preferable to use a pressure filter in that a differential pressure equal to or higher than atmospheric pressure can be obtained. The filtration differential pressure in the pressure filter is preferably 50 kPa or more, more preferably 100 kPa or more, and further preferably 150 kPa or more. Examples of the filter medium at the time of filtration include filter paper, filter cloth, ceramic filter, glass fiber filter, and membrane filter. It is preferable to use a filter cloth because it can withstand the differential pressure during filtration and is excellent in handleability.

[Rinse process]
In the rinsing step, a rinsing solvent is brought into contact with the wet powder after solid-liquid separation, and the rinsing solvent is removed to obtain a wet powder. The rinsing step may be performed on the wet powder after solid-liquid separation in the reprecipitation step, may be performed on the wet powder after solid-liquid separation in the restructuring step, or may be performed on both .
As a rinse solvent, the thing similar to the poor solvent which can be used at a reprecipitation process can be used. It is preferable to select a solvent capable of dissolving the monomer used in the polymerization step and uniformly mixing with the polymerization solvent. It is preferable to use a poor solvent composed of the same type of solvent as the poor solvent used in the reprecipitation step in that the number of types of the poor solvent used in the purification step does not increase and management of the residual solvent is easy. From the viewpoint of production efficiency, it is more preferable to use the same poor solvent as the poor solvent used in the reprecipitation step.

  It is preferable that the rinse solvent is supplied from two or more points with respect to the wet powder. It is preferable to supply from 3 points or more, more preferably 5 points or more, more preferably 10 points or more in terms of being able to supply the rinse solvent uniformly to the wet powder and easily obtaining the effect of removing impurities in the dry powder. Is more preferable, and 20 points or more are particularly preferable. The rinse solvent can be supplied from a plurality of points by using a plurality of nozzles or a shower nozzle. The nozzle diameter is preferably 15 mmφ or less from the viewpoint that the droplet diameter of the rinsing solvent is reduced and it is easy to supply uniformly. It is also preferable to use a shower nozzle. The average particle size of the rinse solvent droplets is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 1 mm or less.

[Resurrection process]
In the slurry process, the wet powder after solid-liquid separation or the wet powder after rinsing is mixed again with a poor solvent, and then solid-liquid separated to obtain a wet powder. This step is an effective purification technique for further reducing impurities such as unreacted monomers and polymerization initiator remaining in the wet powder.
The re-slurry step may be performed on the wet powder after solid-liquid separation in the re-precipitation step, or the re-slurry step may be repeated on the wet powder after solid-liquid separation in the re-slipping step.
Moreover, you may perform a rinse process, before performing a reflow process with respect to the wet powder after solid-liquid separation in the reprecipitation process or the recycle process. That is, you may perform a recycle process with respect to the wet powder after a rinse.
In order to further reduce impurities in the purification step, it is preferable to perform the recycle step twice or more, more preferably three times or more. The number of restructuring steps in the purification step is preferably 6 times or less, more preferably 5 times or less, in that the process time does not become too long.

  The poor solvent used in the re-slurry process can be the same as the poor solvent that can be used in the reprecipitation process. It is preferable to use a poor solvent composed of the same type of solvent as the poor solvent used in the reprecipitation step in that the number of types of the poor solvent used in the purification step does not increase and management of the residual solvent is easy. In addition, when a poor solvent having a different SP value is used in the re-precipitation process, the poor solvent used in the re-precipitation process makes it easy to remove impurities of a different type from the re-precipitation process in the re-precipitation process. This is preferable in that the impurities present in the polymerization reaction solution are easily reduced efficiently.

  It is preferable to perform the operation under the same temperature conditions as in the reprecipitation step for the slurry in the re-slurry step.

As the solid-liquid separation method in the slurry process, the same method as the solid-liquid separation in the reprecipitation step can be used.
In this invention, when the process performed at the end in a refinement | purification process is a recycle process, solid-liquid separation is performed so that the solid content of the wet powder obtained by this recycle process may be 40 mass% or more. As a method for increasing the solid content of the wet powder, solid-liquid separation is performed using a pressure filter, a vacuum filter, or a centrifuge, and the same method as described in the reprecipitation step is used. A method of adjusting operation conditions such as pressure, centrifugal force, and operation time so that the amount of liquid removal is increased is preferable.

[Post-process]
By drying the wet powder obtained by filtering the precipitate in the poor solvent, a dry powder of the target polymer can be obtained.

Further, the wet powder may be used as a lithography composition by dissolving it in a suitable solvent without drying and may be used as a lithography composition after concentration to remove low boiling point compounds. Good. At that time, additives such as a storage stabilizer may be appropriately added.
Alternatively, the moist powder may be dried and then dissolved in an appropriate solvent, and further concentrated to remove the low boiling point compound, and then used as a lithography composition. At that time, additives such as a storage stabilizer may be added as appropriate.
<Polymer>
The polymer for lithography in the present invention (hereinafter sometimes simply referred to as polymer) is not particularly limited as long as it is a polymer used in the lithography process. For example, a resist polymer used for forming a resist film, an antireflection film (TARC) formed on the upper layer of the resist film, or a reflection used for forming an antireflection film (BARC) formed on the lower layer of the resist film. Examples thereof include a polymer for prevention film, a gap fill film polymer used for forming a gap fill film, and a polymer for top coat film used for forming a top coat film.
The polymer for lithography of the present invention is preferably a copolymer containing a constitutional unit having a polar group from the viewpoint of adhesion of the polymer to a hydrophilic surface and affinity for a polar solvent. The structural unit having a polar group will be described later. Constitutional units other than the constitutional unit having a polar group can be appropriately selected and contained from known constitutional units in the polymer for lithography according to the use and the like.

Examples of the polymer for the antireflection film include a structural unit having a light-absorbing group and an amino group, an amide group, a hydroxy group, an epoxy group, etc. that can be cured by reacting with a curing agent to avoid mixing with the resist film And a copolymer containing a structural unit having a reactive functional group. The light-absorbing group is a group having high absorption performance with respect to light in a wavelength region where the photosensitive component in the resist composition is sensitive. Specific examples include an anthracene ring, naphthalene ring, benzene ring, quinoline ring. , A group having a ring structure (optionally substituted) such as a quinoxaline ring and a thiazole ring. In particular, when KrF laser light is used as irradiation light in the lithography process, an anthracene ring or an anthracene ring having an arbitrary substituent is preferable, and when ArF laser light is used, a benzene ring or an arbitrary substituent A benzene ring having is preferred.
Examples of the optional substituent on the anthracene ring include a phenolic hydroxyl group, an alcoholic hydroxyl group, a carboxy group, a carbonyl group, an ester group, an amino group, and an amide group. Among these, those having a protected or unprotected phenolic hydroxyl group as the light absorbing group are preferable from the viewpoint of good developability and high resolution. Examples of the structural unit / monomer having the light-absorbing group include benzyl (meth) acrylate and p-hydroxyphenyl (meth) acrylate.

Examples of polymers for gap fill films are reactive functionalities that have a suitable viscosity for flowing into narrow gaps and can be cured by reacting with curing agents to avoid mixing with resist films and antireflection films. Examples thereof include a copolymer containing a structural unit having a group. Specific examples include copolymers of hydroxystyrene and monomers such as styrene, alkyl (meth) acrylate, and hydroxyalkyl (meth) acrylate.
Examples of the polymer for the topcoat film used in immersion lithography include a copolymer containing a structural unit having a carboxyl group, a copolymer containing a structural unit having a fluorine-containing group substituted with a hydroxyl group, and the like.

  The resist polymer preferably includes one or more structural units having an acid leaving group, and one or more structural units having an acid leaving group and one or more structural units having a polar group. The copolymer containing is more preferable.

[Structural unit having a polar group]
The “polar group” is a group having a polar functional group or a polar atomic group. Specific examples include a hydroxy group, a cyano group, an alkoxy group, a carboxy group, an amino group, a carbonyl group, and a fluorine atom. A group containing a sulfur atom, a group containing a lactone skeleton, a group containing an acetal structure, a group containing an ether bond, and the like.
Among these, the resist polymer applied to the pattern forming method that is exposed to light having a wavelength of 250 nm or less preferably has a structural unit having a lactone skeleton as the structural unit having a polar group, It is preferable to have a structural unit having a functional group.

(Constitutional unit / monomer having a lactone skeleton)
Examples of the lactone skeleton include a lactone skeleton having about 4 to 20 members. The lactone skeleton may be a monocycle having only a lactone ring, or an aliphatic or aromatic carbocyclic or heterocyclic ring may be condensed with the lactone ring.
In the case where the polymer contains a structural unit having a lactone skeleton, the content thereof is preferably 20 mol% or more, more preferably 25 mol% or more of all structural units (100 mol%) from the viewpoint of adhesion to a substrate or the like. Is more preferable. Moreover, from the point of a sensitivity and resolution, 60 mol% or less is preferable, 55 mol% or less is more preferable, and 50 mol% or less is further more preferable.

  As a monomer having a lactone skeleton, a (meth) acrylic acid ester having a substituted or unsubstituted δ-valerolactone ring, a substituted or unsubstituted γ-butyrolactone ring is used because of its excellent adhesion to a substrate or the like. Preferably, at least one selected from the group consisting of monomers having it is preferred, and monomers having an unsubstituted γ-butyrolactone ring are particularly preferred.

Specific examples of the monomer having a lactone skeleton include β- (meth) acryloyloxy-β-methyl-δ-valerolactone, 4,4-dimethyl-2-methylene-γ-butyrolactone, β- (meth) acryloyl. Oxy-γ-butyrolactone, β- (meth) acryloyloxy-β-methyl-γ-butyrolactone, α- (meth) acryloyloxy-γ-butyrolactone, 2- (1- (meth) acryloyloxy) ethyl-4-butanolide , (Meth) acrylic acid pantoyl lactone, 5- (meth) acryloyloxy-2,6-norbornanecarbolactone, 8-methacryloxy-4-oxatricyclo [5.2.1.0 ^2,6 ] decane-3 - one, 9-methacryloxy-4-oxatricyclo [5.2.1.0 ^{2, 6]} cited decan-3-one and the like . Examples of the monomer having a similar structure include methacryloyloxysuccinic anhydride.
Monomers having a lactone skeleton may be used alone or in combination of two or more.

(Structural unit / monomer having a hydrophilic group)
The “hydrophilic group” in the present specification is at least one of —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, a methoxy group, a carboxy group, and an amino group.
Among these, it is preferable that the resist polymer applied to the pattern forming method exposed to light having a wavelength of 250 nm or less has a hydroxy group or a cyano group as a hydrophilic group.
The content of the structural unit having a hydrophilic group in the polymer is preferably from 5 to 30 mol%, more preferably from 10 to 25 mol%, of the total structural units (100 mol%) from the viewpoint of the resist pattern rectangularity. .

  Examples of the monomer having a hydrophilic group include a (meth) acrylic acid ester having a terminal hydroxy group; a derivative having a substituent such as an alkyl group, a hydroxy group, or a carboxy group on the hydrophilic group of the monomer; Monomers having a cyclic hydrocarbon group (for example, cyclohexyl (meth) acrylate, 1-isobornyl (meth) acrylate, adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, (meth) acrylic acid) Dicyclopentyl, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, etc.) having a hydrophilic group such as a hydroxy group or a carboxy group as a substituent; Can be mentioned.

Specific examples of the monomer having a hydrophilic group include (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxy- (meth) acrylate. -Propyl, 4-hydroxybutyl (meth) acrylate, 3-hydroxyadamantyl (meth) acrylate, 2- or 3-cyano-5-norbornyl (meth) acrylate, 2-cyanomethyl-2-adamantyl (meth) acrylate, etc. Is mentioned. From the point of adhesion to a substrate or the like, 3-hydroxyadamantyl (meth) acrylate, 3,5-dihydroxyadamantyl (meth) acrylate, 2- or 3-cyano-5-norbornyl (meth) acrylate, 2-cyanomethyl- 2-adamantyl (meth) acrylate and the like are preferable.
The monomer which has a hydrophilic group may be used individually by 1 type, and may be used in combination of 2 or more type.

[Constitutional unit having acid leaving group]
When the polymer for lithography of the present invention is used for resist applications, it is preferable to have a structural unit having an acid-eliminable group in addition to the above-mentioned structural unit having a polar group. The structural unit may be further included.
The “acid leaving group” is a group having a bond that is cleaved by an acid, and a part or all of the acid leaving group is removed from the main chain of the polymer by cleavage of the bond.
In the resist composition, a polymer having a structural unit having an acid-eliminable group reacts with an acid component to become soluble in an alkaline solution, and has an effect of enabling resist pattern formation.
The proportion of the structural unit having an acid leaving group is preferably 20 mol% or more, more preferably 25 mol% or more, out of all the structural units (100 mol%) constituting the polymer from the viewpoint of sensitivity and resolution. . Moreover, 60 mol% or less is preferable from the point of the adhesiveness to a board | substrate etc., 55 mol% or less is more preferable, and 50 mol% or less is further more preferable.

The monomer having an acid leaving group may be any compound having an acid leaving group and a polymerizable multiple bond, and known ones can be used. The polymerizable multiple bond is a multiple bond that is cleaved during the polymerization reaction to form a copolymer chain, and an ethylenic double bond is preferable.
Specific examples of the monomer having an acid leaving group include (meth) acrylic acid esters having an alicyclic hydrocarbon group having 6 to 20 carbon atoms and having an acid leaving group. It is done. The alicyclic hydrocarbon group may be directly bonded to an oxygen atom constituting an ester bond of (meth) acrylic acid ester, or may be bonded via a linking group such as an alkylene group.
The (meth) acrylic acid ester has an alicyclic hydrocarbon group having 6 to 20 carbon atoms, and a tertiary carbon atom at the bonding site with the oxygen atom constituting the ester bond of the (meth) acrylic acid ester. A (meth) acrylic acid ester having an alicyclic group or an alicyclic hydrocarbon group having 6 to 20 carbon atoms and a -COOR group (R may have a substituent) on the alicyclic hydrocarbon group. (Meth) acrylic acid ester in which a tertiary hydrocarbon group, a tetrahydrofuranyl group, a tetrahydropyranyl group, or an oxepanyl group is bonded directly or via a linking group is included.

In particular, in the case of producing a resist composition that is applied to a pattern forming method that is exposed to light having a wavelength of 250 nm or less, as a preferred example of a monomer having an acid leaving group, for example, 2-methyl-2- Adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, 1- (1′-adamantyl) -1-methylethyl (meth) acrylate, 1-methylcyclohexyl (meth) acrylate, 1-ethylcyclohexyl ( Examples include meth) acrylate, 1-methylcyclopentyl (meth) acrylate, 1-ethylcyclopentyl (meth) acrylate, isopropyl adamantyl (meth) acrylate, 1-ethylcyclooctyl (meth) acrylate, and the like.
As the monomer having an acid leaving group, one type may be used alone, or two or more types may be used in combination.

<Method for producing resist composition>
The polymer thus obtained and a compound that generates an acid upon irradiation with actinic rays or radiation are mixed to produce a resist composition. The resist composition is a chemically amplified resist composition. Preferably, the polymer and a compound capable of generating an acid upon irradiation with actinic rays or radiation are dissolved in a resist solvent.

[Resist solvent]
As the resist solvent, the solvents listed above as the polymerization solvent can be used.
[Compound that generates acid upon irradiation with actinic ray or radiation]
The compound that generates an acid upon irradiation with actinic rays or radiation can be arbitrarily selected from those that can be used as a photoacid generator for a 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.
0.1-20 mass parts is preferable with respect to 100 mass parts of polymers, and, as for the usage-amount of a photo-acid generator, 0.5-10 mass parts is more preferable.

[Nitrogen-containing compounds]
The chemically amplified resist composition may contain a nitrogen-containing compound. By including the nitrogen-containing compound, the resist pattern shape, the stability over time, and the like are further improved. That is, the cross-sectional shape of the resist pattern becomes closer to a rectangle, and the resist film is irradiated with light, then baked (PEB), and then left for several hours before the next development process. Although it is a line, the occurrence of the deterioration of the cross-sectional shape of the resist pattern is further suppressed when left as such (timed).
The nitrogen-containing compound is preferably an amine, more preferably a secondary lower aliphatic amine or a tertiary lower aliphatic amine.
As for the quantity of a nitrogen-containing compound, 0.01-2 mass parts is preferable with respect to 100 mass parts of polymers.

[Organic carboxylic acid, phosphorus oxo acid or derivative thereof]
The chemically amplified resist composition may contain an organic carboxylic acid, an oxo acid of phosphorus, or a derivative thereof (hereinafter collectively referred to as an acid compound). By including an acid compound, it is possible to suppress deterioration in sensitivity due to the blending of the nitrogen-containing compound, and further improve the resist pattern shape, stability with time of leaving, and the like.
Examples of the organic carboxylic acid include malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid.
Examples of phosphorus oxo acids or derivatives thereof include phosphoric acid or derivatives thereof, phosphonic acid or derivatives thereof, phosphinic acid or derivatives thereof, and the like.
The amount of the acid compound is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the polymer.

[Additive]
The resist composition of the present invention may contain various additives such as surfactants, other quenchers, sensitizers, antihalation agents, storage stabilizers, and antifoaming agents as necessary. Any additive can be used as long as it is known in the art. Further, the amount of these additives is not particularly limited, and may be determined as appropriate.

<Manufacturing method of substrate on which fine pattern is formed>
An example of the manufacturing method of the board | substrate with which the fine pattern was formed of this invention is demonstrated.
First, the resist composition obtained by the production method of the present invention is applied to the surface of a substrate to be processed such as a silicon wafer on which a desired fine pattern is to be formed by spin coating or the like. And the resist film is formed on a board | substrate by drying the to-be-processed board | substrate with which this resist composition was apply | coated by baking process (prebaking) etc.

Next, the resist film is irradiated with light having a wavelength of 250 nm or less through a photomask to form a latent image (exposure). As irradiation light, a KrF excimer laser, an ArF excimer laser, an F ₂ excimer laser, and an EUV excimer laser are preferable, and an ArF excimer laser is particularly preferable. Moreover, you may irradiate an electron beam.
In addition, immersion in which light is irradiated with a high refractive index liquid such as pure water, perfluoro-2-butyltetrahydrofuran, or perfluorotrialkylamine interposed between the resist film and the final lens of the exposure apparatus. Exposure may be performed.

After the exposure, heat treatment is appropriately performed (post-exposure baking, PEB), an alkali developer is brought into contact with the resist film, and the exposed portion is dissolved in the developer and removed (development). Examples of the alkaline developer include known ones.
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.

The substrate on which the resist pattern is formed is appropriately heat-treated (post-baked) to strengthen the resist and selectively etch the portion without the resist.
After etching, the resist is removed with a release agent to obtain a substrate on which a fine pattern is formed.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. In addition, “part” in each example and comparative example means “part by mass” unless otherwise specified. The measurement method and evaluation method used the following methods.

<Measurement of weight average molecular weight>
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymer were determined in terms of polystyrene by gel permeation chromatography under the following conditions (GPC conditions).
[GPC conditions]
Equipment: Tosoh Corporation, Tosoh High Speed GPC Equipment HLC-8220GPC (trade name),
Separation column: manufactured by Showa Denko, Shodex GPC K-805L (trade name) connected in series,
Measurement temperature: 40 ° C.
Eluent: Tetrahydrofuran (THF)
Sample: A solution in which about 20 mg of a polymer is dissolved in 5 mL of THF and filtered through a 0.5 μm membrane filter.
Flow rate: 1 mL / min,
Injection volume: 0.1 mL,
Detector: differential refractometer.

Calibration curve I: About 20 mg of standard polystyrene was dissolved in 5 mL of THF, and the solution was filtered through a 0.5 μm membrane filter and injected into a separation column under the above conditions, and the relationship between elution time and molecular weight was determined. As the standard polystyrene, the following standard polystyrene manufactured by Tosoh Corporation (both trade names) were used.
F-80 (Mw = 706,000),
F-20 (Mw = 190,000),
F-4 (Mw = 37,900),
F-1 (Mw = 10,200),
A-2500 (Mw = 2,630),
A-500 (mixture of Mw = 682, 578, 474, 370, 260).

Measurement time 0 to 3 minutes: A liquid / B liquid = 90 vol% / 10 vol%.
Measurement time: 3 to 24 minutes: A liquid / B liquid = 90 volume% / 10 volume% to 50 volume% / 50 volume%.
Measurement time: 24 to 36.5 minutes: A liquid / B liquid = 50 volume% / 50 volume% to 0 volume% / 100 volume%.
Measurement time: 36.5 to 44 minutes: Liquid A / liquid B = 0 volume% / 100 volume%.

<Measurement of residual monomer>
The amount of residual monomer in the dry pulverized or solution (including concentrated liquid) lithographic polymer obtained in the commercialization step is determined by the following method.
0.5 g of a lithographic polymer in the form of a dry powder or solution was collected, diluted with acetonitrile, and made up to a total volume of 50 mL using a volumetric flask. The diluted solution was filtered through a 0.2 μm membrane filter, and the unreacted monomer content in the diluted solution was determined by using a high performance liquid chromatograph HPLC-8020 (product name) manufactured by Tosoh Corporation. Asked for each body. The mass ratio (% by mass) in the polymer of the total monomer amount was defined as the content of the monomer remaining in the polymer. Below the lower limit of detection, the residual monomer amount was 0% by mass.
The amount of residual monomer (unit: mass%) measured by this method is the mass of the solid content of the dry-powder-like lithographic polymer or solution-like lithographic polymer obtained in the commercialization process. Is the ratio when 100% by mass.

In the measurement by the high performance liquid chromatograph, the separation column uses one Inertsil ODS-2 (trade name) manufactured by GL Sciences, the mobile phase is a water / acetonitrile gradient system, the flow rate is 0.8 mL / min, the detector. Was measured with an ultraviolet / visible absorptiometer UV-8020 (trade name) manufactured by Tosoh Corporation, a detection wavelength of 220 nm, a measurement temperature of 40 ° C., and an injection amount of 4 μL. The separation column Inertsil ODS-2 (trade name) used was a silica gel particle diameter of 5 μm, a column inner diameter of 4.6 mm × column length of 450 mm. The gradient conditions of the mobile phase were as follows, with the liquid A being water and the liquid B being acetonitrile. In order to quantify the monomer content, three types of monomer solutions having different concentrations were used as standard solutions.
Measurement time 0 to 3 minutes: A liquid / B liquid = 90 vol% / 10 vol%.
Measurement time: 3 to 24 minutes: A liquid / B liquid = 90 volume% / 10 volume% to 50 volume% / 50 volume%.
Measurement time: 24 to 36.5 minutes: A liquid / B liquid = 50 volume% / 50 volume% to 0 volume% / 100 volume%.
Measurement time: 36.5 to 44 minutes: Liquid A / liquid B = 0 volume% / 100 volume%.

<Evaluation of resist composition>
[Sensitivity and development contrast measurement]
The resist composition was spin-coated on a 6-inch silicon wafer and prebaked (PAB) at 120 ° C. for 60 seconds on a hot plate to form a thin film having a thickness of 300 nm. Using an ArF excimer laser exposure apparatus (product name: VUVES-4500, manufactured by RISOTEC Japan), 18 shots of 10 mm × 10 mm ² were exposed while changing the exposure amount. Then, after post-baking (PEB) at 110 ° C. for 60 seconds, 2.38 mass% tetramethylammonium hydroxide at 23 ° C. using a resist development analyzer (product name: RDA-800). Development was performed with an aqueous solution for 65 seconds, and the change with time in the resist film thickness during development at each exposure amount was measured.

[analysis]
A curve plotting the logarithm of the exposure amount (mJ / cm ² ) and the residual film thickness ratio (hereinafter referred to as the residual film ratio) (%) when developed for 60 seconds with respect to the initial film thickness, based on the obtained data (Hereinafter, exposure amount-residual film rate curve) was prepared, and Eth sensitivity (required exposure amount for setting the residual film rate to 0%, which represents sensitivity) was determined as follows. It shows that the sensitivity of a resist composition is so high that the value of Eth sensitivity is small.
Eth sensitivity: exposure amount (mJ / cm ² ) at which the exposure amount-residual film rate curve intersects with a residual film rate of 0%.

<Example 1>
24.20 kg of ethyl lactate was placed in a 100 L SUS flask (polymerization vessel) equipped with a nitrogen inlet, a stirrer, a condenser, a dropping funnel, and a thermometer. The inside of the flask was replaced with nitrogen, the flask was placed in a hot water bath while maintaining the nitrogen atmosphere, and the temperature of ethyl lactate in the flask was raised to 80 ° C. while stirring the inside of the flask.
Thereafter, the following mixture 1 was dropped into the flask over 4 hours from the dropping funnel, and the temperature of 80 ° C. was further maintained for 3 hours.
Then, the reaction liquid in a flask was cooled to 25 degreeC, the polymerization reaction was stopped, and the polymerization reaction solution was obtained [polymerization process].
[Mixture 1]
10.20 kg of a monomer of the following formula (m1),
11.76 kg of a monomer of the following formula (m2),
7.08 kg of a monomer of the following formula (m3),
43.56 kg of ethyl lactate,
Dimethyl-2,2′-azobisisobutyrate (Wako Pure Chemical Industries, V601 (trade name)) 0.828 kg.
The charging ratio (mol%) of each monomer is (m1) / (m2) / (m3) = 40/40/20.

While maintaining the obtained polymerization reaction solution at 25 ° C., the poor solvent was stirred in 750 L of a poor solvent temperature-controlled at 25 ° C. in a 1000 L SUS container equipped with a jacket and a stirrer. While dropping, a polymer (white precipitate) was precipitated. As a poor solvent, a mixed solvent of methanol and water (methanol / water = 80/20 volume ratio) was used.
The liquid containing the precipitate was heated to 40 ° C. with stirring and held for 30 minutes, and then cooled to 25 ° C. by flowing a temperature-controlled refrigerant through the jacket. Table 1 shows the temperature of the flowed refrigerant and the cooling time from 40 ° C to 35 ° C.
Solid-liquid separation was started by a method of separating the precipitate with a pressure filter. The inside of the pressure filter was pressurized to 150 kPa with dry nitrogen that was passed through a 0.1 μm filter, and wet powder was obtained using a polyester filter cloth as the filter medium [reprecipitation step].

Thereafter, the rinsing solvent (methanol / water = 80/20 volume ratio) is sprayed from the spray nozzle in which the average particle diameter of the supply liquid (rinsing solvent) is 590 μm to the moist powder in the pressure filter to form the moist powder. And then washed. The temperature of the rinse solvent was controlled at 20 ° C., and 90 L of rinse solvent was sprayed.
Then, the inside of the pressure filter was pressurized to 150 kPa using dry nitrogen that was passed through a 0.1 μm filter, and the rinse solvent was removed to obtain a wet powder (wet powder after rinse). Rinse process after the process].

Next, the wet powder after the rinsing was mixed again with the same amount of the poor solvent used in the reprecipitation step, and a recycle operation was performed. As a poor solvent, a mixed solvent of methanol and water (methanol / water = 85/15 volume ratio) was used.
The liquid containing the wet powder was heated to 40 ° C. with stirring and held for 30 minutes, and then cooled to 25 ° C. by flowing a temperature-controlled refrigerant through the jacket. Table 1 shows the temperature of the flowed refrigerant and the cooling time from 40 ° C to 35 ° C.
Solid-liquid separation was started by a method of separating the precipitate with a pressure filter. The inside of the pressure filter was pressurized to 150 kPa with dry nitrogen that was passed through a 0.1 μm filter, and a wet powder was obtained using a polyester filter cloth as a filter medium [lithographic step].

  Thereafter, in the rinsing step after the reprecipitation step, the rinsing solvent is changed to a mixed solution of methanol / water = 85/15 volume ratio. The process was performed [the rinsing process after the restructuring process].

The post-process was performed using the wet powder obtained in the rinse process after the reslurry process as the dry powder of the purified polymer.
That is, 200 g of purified polymer wet powder (room temperature) was dissolved in 2000 g of PGMEA in an atmosphere at 25 ° C. Next, the obtained solution was filtered through a cartridge filter made of nylon having a pore size of 0.04 μm. The obtained filtrate is concentrated under the conditions of a pressure of 20 kPa and a temperature of 50 ° C., and when the distillate no longer comes out, the condition is changed to a pressure of 3 kPa and a temperature of 65 ° C. until the solid content reaches 25% by mass. Concentration was performed to obtain a concentrated liquid polymer for lithography [post-process].
About the polymer in the obtained concentrate (PGMEA solution), the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were measured by said method. The results are shown in Table 1 (the same applies hereinafter).
Moreover, the amount of residual monomers in the obtained concentrated liquid (PGMEA solution) was measured by the above method. The results are shown in Table 1 (the same applies hereinafter).

[Evaluation of resist composition]
A resist composition was prepared using the obtained concentrated liquid. That is, to 400 parts of the concentrated solution, 2 parts of triphenylsulfonium triflate as a photoacid generator was added, and further PGMEA as a solvent was added so that the solid content was 12.5% by mass. After mixing to obtain a uniform solution, the mixture was filtered through a membrane filter having a pore size of 0.1 μm to obtain a resist composition. Eth sensitivity of the obtained resist composition was measured by the above method. The results are shown in Table 1.

Under the same conditions, the polymer was further produced twice (Production 2, 3). The temperature of the refrigerant passed through the jacket each time and the weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), and residual monomer amount of the polymer in the concentrated liquid (PGMEA solution) obtained each time were measured. The standard deviation of the amount of residual monomers in Production 1 to 3 was obtained and used as the difference between lots of the amount of residual monomers. The results are shown in Table 1 (hereinafter the same).
A resist composition was prepared under the same conditions using the polymers obtained each time, and the sensitivity (Eth) was evaluated. The results are shown in Table 1 (hereinafter the same).

<Example 2>
In the polymerization step of Example 1, the polymerization vessel was changed to a 200 L capacity SUS flask (polymerization vessel), the polymerization solvent was changed to 52.20 kg of PGMEA, and the monomer mixture was changed to the mixture 2 below. The polymerization step was carried out in the same manner as in Example 1 [Polymerization step].
[Mixture 2]
20.40 kg of the monomer of the formula (m1),
28.08 kg of a monomer of the following formula (m4),
14.16 kg of the monomer of the formula (m3),
PGMEA 93.96 kg,
4.486 kg of dimethyl-2,2′-azobisisobutyrate (manufactured by Wako Pure Chemical Industries, Ltd., V601 (trade name)).
The charging ratio (mol%) of each monomer is (m1) / (m4) / (m3) = 40/40/20.

While maintaining the resulting polymerization reaction solution at 20 ° C., the poor solvent was stirred into 1500 L of a poor solvent temperature-controlled at 20 ° C. in a 2000 L SUS container equipped with a jacket and a stirrer. While dropping, a polymer (white precipitate) was precipitated. As a poor solvent, a mixed solvent of methanol and water (methanol / water = 80/20 volume ratio) was used.
The liquid containing the precipitate was heated to 40 ° C. with stirring and held for 30 minutes, and then cooled to 25 ° C. by flowing a temperature-controlled refrigerant through the jacket. Table 1 shows the temperature of the flowed refrigerant and the cooling time from 40 ° C to 35 ° C.
Solid-liquid separation was started by a method of separating the precipitate with a pressure filter. The inside of the pressure filter was pressurized to 150 kPa with dry nitrogen that was passed through a 0.1 μm filter, and wet powder was obtained using a polyester filter cloth as the filter medium [reprecipitation step].

Thereafter, the rinsing solvent (methanol / water = 80/20 volume ratio) is sprayed from the spray nozzle in which the average particle diameter of the supply liquid (rinsing solvent) is 590 μm to the moist powder in the pressure filter to form the moist powder. And then washed. The temperature of the rinse solvent was controlled at 20 ° C., and 180 L of rinse solvent was sprayed.
Then, the inside of the pressure filter was pressurized to 150 kPa using dry nitrogen that was passed through a 0.1 μm filter, and the rinse solvent was removed to obtain a wet powder (wet powder after rinse). Rinse process after the process].

Next, the wet powder after the rinsing was mixed again with the same amount of the poor solvent used in the reprecipitation step, and a recycle operation was performed. As a poor solvent, a mixed solvent of methanol and water (methanol / water = 85/15 volume ratio) was used.
The liquid containing the wet powder was heated to 40 ° C. with stirring and held for 30 minutes, and then cooled to 25 ° C. by flowing a temperature-controlled refrigerant through the jacket. Table 1 shows the temperature of the flowed refrigerant and the cooling time from 40 ° C to 35 ° C.
Solid-liquid separation was started by a method of separating the precipitate with a pressure filter. The inside of the pressure filter was pressurized to 150 kPa with dry nitrogen that was passed through a 0.1 μm filter, and a wet powder was obtained using a polyester filter cloth as a filter medium [lithographic step].

  Thereafter, in the rinsing step after the reprecipitation step, the rinsing solvent is changed to a mixed solution of methanol / water = 85/15 volume ratio. The process was performed [the rinsing process after the restructuring process].

The wet powder obtained in the rinsing step after the re-slurry step was subjected to a post step in the same manner as in Example 1 to obtain a concentrated liquid polymer for lithography [post step].
About the polymer in the obtained concentrate (PGMEA solution), the weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) were measured in the same manner as in Example 1. The results are shown in Table 1 (the same applies hereinafter).
Further, the amount of residual monomer in the obtained concentrated liquid (PGMEA solution) was measured in the same manner as in Example 1. The results are shown in Table 1 (the same applies hereinafter).

[Evaluation of resist composition]
Using the obtained concentrated solution, a resist composition was prepared in the same manner as in Example 1, and the Eth sensitivity of the obtained resist composition was measured. The results are shown in Table 1.

Under the same conditions, the polymer was further produced twice (Production 2, 3). The temperature of the refrigerant passed through the jacket each time and the weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), and residual monomer amount of the polymer in the concentrated liquid (PGMEA solution) obtained each time were measured. The standard deviation of the amount of residual monomers in Production 1 to 3 was obtained and used as the difference between lots of the amount of residual monomers. The results are shown in Table 1 (hereinafter the same).
A resist composition was prepared under the same conditions using the polymers obtained each time, and the sensitivity (Eth) was evaluated. The results are shown in Table 1 (hereinafter the same).

<Comparative Example 1>
In the reprecipitation step, a polymer was produced and evaluated in the same manner as in Example 1 except that the jacket was cooled by flowing non-temperature-controlled water during cooling after heating. Table 1 shows the temperature and evaluation results of the water flowing into the jacket.

Under the same conditions, the polymer was further produced twice (Production 2, 3). Table 1 shows the temperature of the water passed through the jacket and the evaluation results of the obtained polymer.
<Comparative Example 2>
In the reprecipitation step, a polymer was produced and evaluated in the same manner as in Example 2 except that the jacket was cooled by flowing non-temperature-controlled water during cooling after heating. Table 1 shows the temperature and evaluation results of the water flowing into the jacket.

  Under the same conditions, the polymer was further produced twice (Production 2, 3). Table 1 shows the temperature of the water passed through the jacket and the evaluation results of the obtained polymer.

As shown in the results of Table 1, in Examples 1 and 2 according to the present invention, cooling was performed by flowing unheated water to the jacket during cooling after heating in the refining process. Compared with Comparative Examples 1 and 2 in which the time required for exceeds 120 minutes, the amount of residual monomer is stable between lots, indicating good production reproducibility.
Further, the polymers obtained in Examples 1 and 2 have stable sensitivity when used in resist compositions and can exhibit uniform performance.

Claims (4)

A polymerization step in which a monomer is radically polymerized using a polymerization initiator in the presence of a polymerization solvent to obtain a polymerization reaction solution;
A purification step of mixing the polymerization reaction solution with a poor solvent for the polymer to precipitate the polymer, heating the precipitated polymer and solvent slurry, and cooling the precipitate within 5 minutes by cooling at 5 ° C or higher. A method for producing a polymer, comprising 10 kg or more of polymer per batch.   The manufacturing method of the polymer of Claim 1 which performs the said refinement | purification process using a 1000L or more container provided with the heat exchange equipment.   A method for producing a resist composition, comprising mixing a polymer obtained by the method for producing a polymer according to claim 1 or 2 and a compound capable of generating an acid upon irradiation with actinic rays or radiation. Applying a resist composition obtained by the method for producing a resist composition according to claim 3 on a work surface of a substrate to form a resist film; and exposing the resist film; A method for producing a substrate on which a pattern is formed, comprising: developing the exposed resist film using a developer.