JP5092721B2 - Manufacturing method of resin for photoresist - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing resin for photoresist by which the resin for photoresist is efficiently separated from a slurry solution containing the resin for photoresist with high filtration speed. <P>SOLUTION: The method of producing the resin for the photoresist by polymerizing a polymerizable compound in the presence of a solvent includes: (1) a resin solution preparation step of preparing a resin solution containing the resin for photoresist; (2) a purification step of purifying the solution by re-precipitation; (3) a cooling step of cooling the slurry solution containing the resin for photoresist after purification; and (4) a filtration step of separating the resin for photoresist by filtering the cooled slurry solution. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a photoresist resin. More specifically, the present invention relates to a method for producing a photoresist resin, which has a high filtration rate and can efficiently separate the photoresist resin from a slurry solution containing the photoresist resin.

In the field of microfabrication represented by the manufacture of integrated circuit elements, lithography technology capable of finer processing is required to obtain a higher degree of integration. However, in the conventional lithography process, near ultraviolet rays such as i rays are generally used as radiation, and it is said that fine processing at the subquarter micron level is extremely difficult with this near ultraviolet rays. Therefore, for example, in order to enable fine processing at a level of 0.10 μm or less, use of radiation having a shorter wavelength is being studied. Examples of such short-wavelength radiation include an emission line spectrum of a mercury lamp, far-ultraviolet rays typified by an excimer laser, an X-ray, an electron beam, and the like. ) Or ArF excimer laser (wavelength 193 nm) has been attracting attention.
And for photolithography such as a radiation sensitive resin composition for resist formation suitable for irradiation by such radiation, a resin composition for forming an upper layer film or a lower layer film (antireflection film, etc.) in a multilayer resist. Many resin compositions used have been proposed.

The resin contained in the resin composition used for photolithography includes physical properties such as optical properties, chemical properties, coating properties, and adhesion to the substrate or lower layer film required for resist films and antireflection films. In addition to these properties, there is a demand for basic properties as a resin for forming a coating film, such as the absence of foreign matter that prevents fine pattern formation. If impurities added or generated during the polymerization reaction, such as unreacted monomers, polymerization initiators and chain transfer agents, and their coupling products remain in the resin contained in this resin composition, they will volatilize in lithography. As a result, the exposure apparatus may be damaged, or a substance that causes pattern defects may be generated by polymerization during storage as a resin or a resin composition for lithography.
Accordingly, when the resin is produced, a purification step for removing these impurities is required, and conventionally, various methods for producing and purifying a resin including a resin purification step by reprecipitation are known ( For example, see Patent Documents 1 to 3).

JP 2002-201210 A JP 2002-229220 A JP 2005-132974 A

  However, in the conventional resin production method, it cannot be said that the filtration efficiency in separating the resin is sufficient, and in order to improve productivity, the filtration efficiency is improved by increasing the filtration speed, downsizing the filtration device, etc. The current situation is that further improvement is required.

  The present invention has been made in view of the above circumstances, and by providing a step of cooling a slurry solution containing a photoresist resin before the filtration step, the filtration rate can be improved as compared with the prior art. It is an object of the present invention to provide a method for producing a photoresist resin capable of efficiently separating a photoresist resin from a slurry solution containing the resist resin.

The present invention is as follows.
[1] A method for producing a photoresist resin by polymerizing a polymerizable compound in the presence of a solvent, wherein (1) a resin solution containing the photoresist resin is prepared. A resin solution preparation step, (2) a purification step in which the resin solution and a poor solvent are brought into contact with each other without heating, and a photoresist resin is purified by reprecipitation; and (3) a photoresist after purification. A photoresist resin comprising: a cooling step of cooling a slurry solution containing a resin; and (4) a filtration step of separating the photoresist resin by filtering the cooled slurry solution. Manufacturing method.
[2] The method for producing a photoresist resin according to [1], wherein a temperature difference between before and after cooling the slurry solution in the cooling step is 5 to 20 ° C.
[3] The method for producing a photoresist resin according to [1] or [2], wherein the temperature of the slurry solution after cooling in the cooling step is −10 to 30 ° C.
[4] The method for producing a photoresist resin according to any one of [1] to [3], wherein the poor solvent used in the purification step is at least one of an alcohol solvent and a hydrocarbon solvent.

  According to the method for producing a resin for photoresist of the present invention, a slurry solution containing a purified resin is provided between a purification step by reprecipitation and a filtration step of separating the resin (copolymer) from the slurry solution. Since a cooling step for cooling is provided, the filtration rate when separating the resin by filtration can be significantly improved as compared with the conventional method. Therefore, the filtration time can be shortened and the size of the filtration device can be reduced, and the productivity of the photoresist resin can be improved.

Hereinafter, the present invention will be described in detail.
The method for producing a photoresist resin according to the present invention is a method for producing a photoresist resin by polymerizing a polymerizable compound in the presence of a solvent, and (1) a resin solution containing a photoresist resin. And (2) a purification step for refining the photoresist resin by reprecipitation by bringing the resin solution into contact with the poor solvent without heating , and (3) after purification. A cooling step for cooling the slurry solution containing the photoresist resin; and (4) a filtration step for separating the photoresist resin by filtering the cooled slurry solution.

[1] Resin Solution Preparation Step In the resin solution preparation step, a resin solution containing a photoresist resin is prepared by polymerizing a polymerizable compound in the presence of a solvent.
The polymerizable compound is usually used for photolithography of a radiation-sensitive resin composition for resist formation, a resin composition for forming an upper layer film or a lower layer film (antireflection film, etc.) in a multilayer resist. The polymeric compound (monomer) which has an ethylenically unsaturated bond used for manufacture of the resin for photoresists contained in a resin composition can be mentioned.

  Here, for example, the resin contained in the positive-type radiation-sensitive resin composition for resist formation is at least a repeating unit having a chemical structure that is decomposed by an acid and becomes soluble in an alkali developer, more specifically, And a repeating unit (1) having a chemical structure in which a non-polar substituent is dissociated by an acid and a polar group soluble in an alkali developer is expressed, and a polar group for enhancing adhesion to a substrate such as a semiconductor substrate The repeating unit (2) is an essential component, and includes a repeating unit (3) having a non-polar substituent for adjusting the solubility in a solvent or an alkali developer as necessary. .

  The repeating unit (1) that is decomposed by an acid and becomes alkali-soluble means a chemical structure generally used as a conventional resist, and a monomer having a chemical structure that is decomposed by an acid and becomes alkali-soluble. After polymerizing or polymerizing a monomer having an alkali-soluble chemical structure, the substituent having an alkali-soluble group (alkali-soluble group) in the alkali-soluble chemical structure is dissociated by an acid without being dissolved in the alkali. It can be obtained by protecting with a group (acid-dissociable protecting group).

Examples of the monomer having a chemical structure that becomes alkali-soluble when decomposed by an acid include compounds in which an acid-dissociable protecting group is bonded to a polymerizable compound containing an alkali-soluble substituent. And compounds having a phenolic hydroxyl group, a carboxyl group or a hydroxyfluoroalkyl group protected with an acid dissociable protecting group. Specifically, for example, hydroxystyrenes such as p-hydroxystyrene, m-hydroxystyrene, p-hydroxy-α-methylstyrene; acrylic acid, methacrylic acid, maleic acid, fumaric acid, α-trifluoromethylacrylic acid , 5-norbornene-2-carboxylic acid, 2-trifluoromethyl-5-norbornene-2-carboxylic acid, carboxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] carboxylic acids having an ethylenic double bond such as dodecyl methacrylate; p- (2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl) styrene, 2- ( 4- (2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl) cyclohexyl) -1,1,1,3,3,3-hexafluoropropyl acrylate, 2- (4 -(2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl) cyclohexyl) -1,1,1,3,3,3-hexafluoropropyltrifluoromethyl acrylate, 5- Polymerizable compounds having a hydroxyfluoroalkyl group such as (2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl) methyl-2-norbornene That.

Examples of the acid dissociable protecting group include a tert-butyl group, a tert-amyl group, a 1-methyl-1-cyclopentyl group, a 1-ethyl-1-cyclopentyl group, and a 1-methyl-1-cyclohexyl group. 1-ethyl-1-cyclohexyl group, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 2-propyl-2-adamantyl group, 2- (1-adamantyl) -2-propyl group, 8-methyl-8-tricyclo [5.2.1.0 ^2,6 ] decanyl group, 8-ethyl-8-tricyclo [5.2.1.0 ^2,6 ] decanyl group, 8-methyl-8- Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl group, 8-ethyl-8-tetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} ] saturated hydrocarbon group such as dodecanyl group; 1-methoxyethyl group, 2-ethoxyethyl group, 1-iso-propoxyethyl group, 1-n-butoxyethyl group, 1-tert-butoxyethyl group, 1-cyclopentyloxyethyl group, 1-cyclohexyloxyethyl group, 1-tricyclo [5.2.1.0 ^2,6 ] decanyloxyethyl group, methoxymethyl group, ethoxymethyl group, iso-propoxymethyl group, n Oxygenated carbon such as -butoxymethyl group, tert-butoxymethyl group, cyclopentyloxymethyl group, cyclohexyloxymethyl group, tricyclo [5.2.1.0 ^2,6 ] decanyloxymethyl group, tert-butoxycarbonyl group A hydrogen group etc. are mentioned.

  After polymerizing a monomer having an alkali-soluble chemical structure and then protecting the alkali-soluble group in the alkali-soluble chemical structure with an acid-dissociable protecting group, the compound having the alkali-soluble group is directly polymerized. Then, an acid-dissociable protecting group can be introduced by reacting with a compound that gives a substituent that does not dissolve in an alkali such as vinyl ether or halogenated alkyl ether under an acid catalyst. Examples of the acid catalyst used in the reaction include p-toluenesulfonic acid, trifluoroacetic acid, and strongly acidic ion exchange resin.

  Examples of the monomer that gives the repeating unit (2) having a polar group for improving adhesion to the substrate include compounds having a phenolic hydroxyl group, a carboxyl group, or a hydroxyfluoroalkyl group as the polar group. Specifically, for example, as the polymerizable compound containing an alkali-soluble group, hydroxystyrenes described above, carboxylic acids having an ethylenic double bond, polymerizable compounds having a hydroxyfluoroalkyl group, and these In addition to the monomer further substituted with a polar group, a monomer having a polar group bonded to an alicyclic structure such as a norbornene ring or a tetracyclododecene ring can be used.

The polar group introduced into the repeating unit (2) as a substituent is particularly preferably one containing a lactone structure, such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, 1,3-cyclohexanecarbolactone. , 2,6-norbornanecarbolactone, 4-oxatricyclo [5.2.1.0 ^2,6 ] decan-3-one, and a substituent containing a lactone structure such as mevalonic acid δ-lactone.
Examples of polar groups other than the lactone structure include hydroxyalkyl groups such as a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, and a 3-hydroxy-1-adamantyl group.

Furthermore, as a monomer which gives the repeating unit (3) having a nonpolar substituent for adjusting the solubility in a resist solvent or an alkali developer, which is contained as necessary, styrene, α-methyl Aromatic compounds having an ethylenic double bond such as styrene, p-methylstyrene, and indene; acrylic acid, methacrylic acid, trifluoromethyl acrylic acid, norbornene carboxylic acid, 2-trifluoromethyl norbornene carboxylic acid, carboxytetracyclo [ 4.4.0.1 ^2,5 . 1 ^7,10 ] ester compound in which acid-stable nonpolar group is substituted for carboxylic acid having ethylenic double bond such as dodecyl methacrylate; alicyclic carbonization having ethylenic double bond such as norbornene and tetracyclododecene A hydrogen compound etc. are mentioned.
Examples of acid-stable nonpolar substituents that are ester-substituted for the carboxylic acid include methyl, ethyl, cyclopentyl, cyclohexyl, isobornyl, and tricyclo [5.2.1.0 ^2,6 ] decanyl. Group, 2-adamantyl group, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecyl group and the like.

These monomers may be used individually by 1 type in each of repeating unit (1), (2), and (3), and may be used in combination of 2 or more type.
The composition ratio of each repeating unit in the resin contained in the positive-type radiation-sensitive resin composition for resist formation can be selected within a range that does not impair the basic performance as a resist. That is, in general, the repeating unit (1) is preferably 10 to 70 mol%, more preferably 10 to 60 mol%. The composition ratio of the repeating unit (2) is preferably 30 to 90 mol%, more preferably 40 to 90 mol%, but for the monomer unit having the same polar group, 70 mol% The following is preferable. Furthermore, the composition ratio of the repeating unit (3) is preferably 50 mol% or less, more preferably 40 mol% or less.

  On the other hand, the resin contained in the resin composition for forming the upper layer film and the lower layer film (antireflection film, etc.) in the multilayer resist is the same as the chemistry of the resin contained in the positive type radiation sensitive resin composition for resist formation described above. A polymer having a chemical structure in which the repeating unit (1) which is decomposed with an acid and becomes alkali-soluble is removed from the structure. The composition ratio of each repeating unit in the resin is not particularly limited, and is appropriately adjusted depending on the intended use of the coating film. Generally, the composition ratio of the repeating unit (2) is selected from the range of 10 to 100 mol%, and the composition ratio of the repeating unit (3) is selected from the range of 0 to 90 mol%.

  Furthermore, when the upper layer film or the lower layer film in the multilayer resist is used as an antireflection film, the resin needs to include a crosslinking point and a chemical structure that absorbs radiation irradiated in photolithography. The point includes reactive substituents that can be cross-linked by an ester bond, a urethane bond, or the like, such as a hydroxyl group, an amino group, a carboxyl group, or an epoxy group. Examples of the monomer containing a reactive substituent serving as a crosslinking point include hydroxystyrenes such as p-hydroxystyrene and m-hydroxystyrene, and the above-described polymerizable compounds such as the hydroxyl group, amino group, and carboxyl. A monomer substituted with a reactive substituent such as a group or an epoxy group can be appropriately used.

  The chemical structure that absorbs radiation varies depending on the wavelength of the radiation used. For example, for ArF excimer laser light, a chemical structure containing a benzene ring and its analogs is preferably used. Examples of the monomer having such a chemical structure include styrenes such as styrene, α-methylstyrene, p-methylstyrene, p-hydroxystyrene, m-hydroxystyrene, and derivatives thereof; substituted or unsubstituted phenyl (meta And aromatic-containing esters having an ethylenic double bond such as acrylate, substituted or unsubstituted naphthalene (meth) acrylate, substituted or unsubstituted anthracenemethyl (meth) acrylate, and the like. The monomer having a chemical structure that absorbs radiation may be introduced as either the repeating unit (2) or (3) depending on the presence or absence of a polar group, but the monomer having a chemical structure that absorbs radiation. Is preferably selected from the range of 10 to 100 mol%. In the present specification, “(meth) acrylate” means acrylate and methacrylate.

Moreover, the polymerization method of the said polymeric compound is not specifically limited, Well-known methods, such as solution polymerization, can be used.
The resin solution containing the photoresist resin uses, for example, a polymerization initiator, and further uses a chain transfer agent as necessary, and the above-described polymerizable compound (that is, polymerizable unsaturated monomer). Can be obtained by polymerizing in a suitable solvent.

  Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), dimethyl 2,2′-azobisisobutyrate, 1,1′- Azo compounds such as azobis (cyclohexane-1-carbonitrile), 4,4′-azobis (4-cyanovaleric acid), decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, bis (3,5,5-trimethyl) Hexanoyl) peroxide, succinic acid peroxide, radical polymerization initiators such as organic peroxides such as tert-butylperoxy-2-ethylhexanoate. These polymerization initiators may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the chain transfer agent include thiol compounds such as dodecyl mercaptan, mercaptoethanol, mercaptopropanol, mercaptoacetic acid, mercaptopropionic acid, and 4,4-bis (trifluoromethyl) -4-hydroxy-1-mercaptobutane. be able to. These chain transfer agents may be used individually by 1 type, and may be used in combination of 2 or more type.

The amount of the polymerization initiator and chain transfer agent used is a raw material monomer (polymerizable compound) used in the polymerization reaction, a polymerization initiator, the type of chain transfer agent, a polymerization temperature, a polymerization solvent, a polymerization method, purification conditions, and other production conditions. Can be adjusted as appropriate.
In general, if the weight average molecular weight of the resin is too high, the solubility in a solvent or an alkali developer used for forming a coating film tends to be low. On the other hand, when the weight average molecular weight is too low, the coating film performance tends to deteriorate. Therefore, the polystyrene-reduced weight average molecular weight (hereinafter also referred to as “Mw”) by gel permeation chromatography (GPC) is preferably adjusted to be in the range of 2000 to 40000, more preferably 3000 to 30000.

  Examples of the solvent (polymerization solvent) used in the polymerization reaction include ketones such as acetone, methyl ethyl ketone, methyl amyl ketone, and cyclohexanone; ethers such as tetrahydrofuran, dioxane, glyme, and propylene glycol monomethyl ether; ethyl acetate, Examples include esters such as ethyl lactate; ether esters such as propylene glycol methyl ether acetate, and lactones such as γ-butyrolactone. These solvents may be used alone or in combination of two or more.

  Although the usage-amount of the said solvent is not specifically limited, Usually, it is 0.5-20 mass parts with respect to 1 mass part of monomers, Preferably it is 1-10 mass parts. If the amount of the solvent used is too small, the monomer may precipitate or become too viscous to keep the polymerization system uniform. On the other hand, when the amount of the solvent used is too large, the conversion rate of the raw material monomers may be insufficient, or the molecular weight of the resulting resin may not be increased to a desired value.

  Moreover, the reaction conditions in the said polymerization are not specifically limited, However, Reaction temperature is 40-120 degreeC normally, Preferably it is 50-100 degreeC. The reaction time is usually 1 to 48 hours, preferably 1 to 24 hours.

  Moreover, it is preferable that the resin concentration (solid content concentration) of the resin solution obtained in this resin solution preparation process is 1-80 mass%, More preferably, it is 5-50 mass%, More preferably, it is 10-50 mass%. It is.

[2] Purification step In the purification step, impurities (particularly low molecular components such as residual monomers, dimers, trimers, oligomers, etc.) are removed by reprecipitation, and the copolymer (resin for photoresist) is purified. Is called. The analysis of the low molecular component can be performed by high performance liquid chromatography (HPLC).

  The purification method by reprecipitation is not particularly limited, and can be performed according to a conventional method. Specifically, for example, purification can be performed by dropping the resin solution obtained in the resin solution preparation step into a poor solvent. The resin solution may be diluted to a predetermined resin concentration by using a good solvent as necessary. The purification by reprecipitation may be performed only once, or may be performed twice or more using a good solvent as the reprecipitation solvent.

  Examples of the good solvent include the same solvents as those described above. This good solvent may be used alone or in combination of two or more. The good solvent used in this purification step may be the same as or different from the polymerization solvent used in the resin solution preparation step.

The poor solvent is not particularly limited as long as the copolymer is precipitated, and examples thereof include alcohol solvents, hydrocarbon solvents, ether solvents, water, and mixed solvents thereof. Among these, at least one of an alcohol solvent and a hydrocarbon solvent is preferable.
Examples of the alcohol solvent include methanol, ethanol, 1-propanol, 2-propanol and the like. These alcohol solvents may be used alone or in combination of two or more.
Examples of the hydrocarbon solvent include aliphatic hydrocarbons such as pentane, hexane, heptane and octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and aromatic hydrocarbons such as benzene, toluene and xylene. It is done. These hydrocarbon solvents may be used individually by 1 type, and may be used in combination of 2 or more type.

  The usage-amount of the said poor solvent is not specifically limited, It adjusts suitably with the kind of poor solvent, the kind of solvent in a resin solution, and its content. Specifically, for example, it is preferably 0.5 to 50 times, more preferably 1 to 30 times, still more preferably 2 to 20 times in terms of mass with respect to the total amount of the resin solution to be contacted with the poor solvent. Is double.

  Moreover, it is preferable that the temperature of the slurry solution containing the resin for photoresists obtained by the said refinement | purification process is 10-35 degreeC, More preferably, it is 15-35 degreeC, More preferably, it is 20-35 degreeC. The temperature of the slurry solution can be controlled by a temperature control device provided in the purification device, the temperature of the poor solvent used, and the like.

[3] Cooling Step In the cooling step, the slurry solution containing the purified photoresist resin is cooled.
In this cooling step, it is preferable to cool the slurry solution so that the temperature difference before and after cooling is 5 to 20 ° C. (more preferably 8 to 15 ° C., still more preferably 10 to 15 ° C.). When the temperature difference before and after cooling is 5 to 20 ° C., the filtration rate in the filtration step described later can be sufficiently improved. In addition, when this temperature difference is less than 5 degreeC, there exists a possibility that a filtration rate cannot fully be improved. On the other hand, when it exceeds 20 ° C., the time required for cooling becomes long, and there is a possibility that the process time cannot be reduced. Furthermore, the impurities separated in the purification step are precipitated, and thus the purification may be insufficient.

Moreover, it is preferable that the temperature of the said slurry solution after cooling is -10-30 degreeC, More preferably, it is 0-27 degreeC, More preferably, it is 5-25 degreeC.
The cooling means for cooling the slurry solution is not particularly limited. For example, a container or the like in which equipment capable of temperature control such as a temperature control jacket is disposed outside and / or inside the container is used. Alternatively, the slurry solution can be cooled by sending and circulating the slurry solution to an external cooling device.

[4] Filtration step In the filtration step, the cooled slurry solution is filtered to separate the photoresist resin.
The filtration method in this filtration process is not specifically limited, In the conventional resin manufacturing method, it can filter with the filtration apparatus etc. which are used when carrying out solid-liquid separation of the slurry solution containing resin. This filtration step may be performed under atmospheric pressure, or may be performed under pressure or reduced pressure using nitrogen gas or the like.

  Examples of the filtration filter used in the filtration step include polyolefins such as polyester, polyester, nylon (registered trademark), polyethylene, and polypropylene, synthetic fibers such as aramid, acrylic, Teflon (registered trademark), polyphenylene sulfide, and polyimide, or glass fibers. A filter cloth made of, sintered metal or the like is preferably used.

Aeration rate of the filtration filter is desired solids are not particularly limited as far as possible separation, for ^example, is preferably 0.1~300cm ^{3 /} cm 2 · sec, more preferably 0.5～100Cm ³ / Cm ² · sec.

  Moreover, in this invention, you may perform further refinement | purification of the resin for photoresists by wash | cleaning the obtained filter top thing with a poor solvent etc. after the said filtration process. Furthermore, you may provide the drying process for obtaining resin content as a powder.

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

Example 1
Into a three-necked flask having a 500 mL Dimroth tube, 86.5 g of methyl ethyl ketone (MEK) as a polymerization solvent was placed and sufficiently purged with nitrogen, and then heated to 80 ° C. while stirring with a three-one motor. Thereafter, a solution of 35.5 g of 5-methacryloyloxy-2,6-norbornanecarbolactone (NLM) and 47 g of 2-methyl-2-adamantyl methacrylate (MAdMA) in 168 g of MEK, and azobisisobutyronitrile A solution prepared by dissolving 48 g of MEK in 7.4 g was added dropwise over 3 hours using a dropping funnel. After completion of dropping, the mixture was further aged for 3 hours, and then cooled to room temperature to prepare a resin solution. As a result of measurement using high performance liquid chromatography, the monomer conversion was 90%, and the amount of residual monomer relative to 100% by mass of the resin was about 11% by mass. Moreover, as a result of measuring a weight average molecular weight (Mw) and a number average molecular weight (Mn) about the obtained resin, molecular weight distribution (dispersion degree Mw / Mn) was 1.73.

Thereafter, 100 g of the obtained resin solution (resin concentration: about 25% by mass) was dropped into a 500 g methanol solution set at 25 ° C. at a dropping rate of 12.5 g / min, and reprecipitation was performed to obtain white. Slurry solution (solution temperature; 25.7 ° C.) was obtained.
Next, the obtained slurry solution was transferred to a temperature-controllable tank and cooled until the solution temperature reached 15 ° C.
Then, nitrogen pressure was applied at 0.2 MPa using a pressure filter with a Teflon filter cloth (aeration rate: 3.0 cm ³ / cm ² · sec, filtration area: 9.62 cm ² ) on the bottom of the container. Under such conditions, the cooled slurry solution (600 g) was filtered to obtain a white solid. The filtration time at this time was 12 minutes.
Next, the resin solution was further purified by repeating the operation of washing the obtained white solid with 100 g of methanol twice. And as a result of measuring using a high performance liquid chromatography, the amount of residual monomers with respect to 100 mass% of resin was 0.08 mass%. Furthermore, the molecular weight distribution was 1.47.

The Mw and Mn are values measured as follows.
Using Tosoh Co., Ltd. GPC columns (trade name “G2000HXL”, product name “G3000HXL”, product name “G4000HXL” 1), flow rate: 1.0 ml / min, elution solvent: tetrahydrofuran, Column temperature: Measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under analysis conditions of 40 ° C.

(Example 2)
A resin solution (resin concentration; about 25% by mass) was prepared in the same manner as in Example 1, and 100 g of the obtained resin solution was added at a dropping rate of 12.5 g / min into 500 g of methanol solution set at 25 ° C. The solution was added dropwise and reprecipitation was performed to obtain a white slurry solution (solution temperature: 25.5 ° C.).
Next, the obtained slurry solution was transferred to a temperature-controllable tank and cooled until the solution temperature reached 15 ° C.
Then, nitrogen pressure was applied at 0.2 MPa using a pressure filter with a Teflon filter cloth (aeration rate: 1.0 cm ³ / cm ² · sec, filtration area: 9.62 cm ² ) on the bottom of the container. Under such conditions, the cooled slurry solution (600 g) was filtered to obtain a white solid. The filtration time at this time was 13 minutes.
Next, the resin solution was further purified by repeating the operation of washing the obtained white solid with 100 g of methanol twice. And as a result of measuring using high performance liquid chromatography, the amount of residual monomers with respect to 100 mass% of resin was 0.09 mass%. Furthermore, the molecular weight distribution was 1.49.

(Comparative Example 1)
A resin solution (resin concentration; about 25% by mass) was prepared in the same manner as in Example 1, and 100 g of the obtained resin solution was added at a dropping rate of 12.5 g / min into 500 g of methanol solution set at 25 ° C. The solution was added dropwise and reprecipitation was performed to obtain a white slurry solution (solution temperature: 25.3 ° C.).
Then, without cooling the resulting slurry solution (600 g), Teflon filter cloth to the container bottom (aeration ^{rate; 3.0cm 3 / cm 2 · sec} , filtration area: 9.62cm ²⁾ stretched pressurized A white solid was obtained by filtering under the condition of nitrogen pressurization at 0.2 MPa using a filter. The filtration time at this time was 30 minutes.
Next, the resin solution was further purified by repeating the operation of washing the obtained white solid with 100 g of methanol twice. And as a result of measuring using a high performance liquid chromatography, the amount of residual monomers with respect to 100 mass% of resin was 0.08 mass%. Furthermore, the molecular weight distribution was 1.48.

(Comparative Example 2)
A resin solution (resin concentration; about 25% by mass) was prepared in the same manner as in Example 1, and 100 g of the obtained resin solution was added at a dropping rate of 12.5 g / min into 500 g of methanol solution set at 25 ° C. The solution was added dropwise and reprecipitation was performed to obtain a white slurry solution (solution temperature: 25.6 ° C.).
Then, without cooling the resulting slurry solution (600 g), Teflon filter cloth to the container bottom (aeration ^{rate; 1.0cm 3 / cm 2 · sec} , filtration area: 9.62cm ²⁾ stretched pressurized A white solid was obtained by filtering under the condition of nitrogen pressurization at 0.2 MPa using a filter. The filtration time at this time was 32 minutes.
Next, the resin solution was further purified by repeating the operation of washing the obtained white solid with 100 g of methanol twice. And as a result of measuring using high performance liquid chromatography, the amount of residual monomers with respect to 100 mass% of resin was 0.09 mass%. Furthermore, the molecular weight distribution was 1.49.

  From the above results, it was found that the filtration rate can be sufficiently improved by providing a cooling step for cooling the slurry solution between the purification step by reprecipitation and the filtration step for separating the resin. Furthermore, it has been found that the influence on the filtration rate in the filtration step is significantly greater in the presence or absence of the cooling step than in the change in the air flow rate of the filter cloth.

Claims (4)

A method for producing a photoresist resin, which comprises producing a photoresist resin by polymerizing a polymerizable compound in the presence of a solvent,
(1) a resin solution preparation step of preparing a resin solution containing a photoresist resin;
(2) a purification step in which the resin solution and a poor solvent are brought into contact without heating, and a photoresist resin is purified by reprecipitation;
(3) a cooling step of cooling the slurry solution containing the purified photoresist resin;
(4) A method of producing a photoresist resin, comprising: a filtration step of separating the photoresist resin by filtering the cooled slurry solution.   2. The method for producing a photoresist resin according to claim 1, wherein a temperature difference between before and after cooling the slurry solution in the cooling step is 5 to 20 ° C. 3.   The method for producing a photoresist resin according to claim 1 or 2, wherein a temperature after cooling of the slurry solution in the cooling step is -10 to 30 ° C.   The method for producing a photoresist resin according to claim 1, wherein the poor solvent used in the purification step is at least one of an alcohol solvent and a hydrocarbon solvent.