JP2013032508A - Method for producing polymer solution for lithography, method for producing resist composition and method for producing substrate with pattern formed thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polymer solution for lithography which can shorten total transit time of drying time and dissolving time without requiring cooling of solvent or heating at dissolving.SOLUTION: This method for producing the polymer solution comprises: a polymerization step of radically polymerizing a monomer using a polymerization initiator in the presence of a polymerization solvent to obtain a polymerization reaction solution; a recovering step of mixing the polymerization reaction solution with a poor solvent for the polymer to precipitate the polymer to obtain a precipitate; a minor drying step of drying the precipitate so that the solid content falls within the range of 65-90 mass%; and a dissolving step of dissolving the minor dried powder in a good solvent for the polymer to obtain the polymer solution for lithography. In the dissolving step, the temperature of the minor dried powder is 0-45°C and the temperature of the good solvent is 0-40°C.

Description

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

  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.

  A “chemically amplified resist composition” containing a photoacid generator has been proposed as a highly sensitive resist composition used for forming a resist pattern using the irradiation light or electron beam of the short wavelength. Improvement and development of amplification resist compositions are underway.

In a conventional method for producing a polymer for lithography, there is known a method in which a polymerization reaction solution after polymerization reaction is added to a poor solvent to precipitate the polymer, and the recovered polymer powder is dried. When the is dried, the surface of the polymer particles becomes hard and the polymer particles are fused with each other, which makes it difficult to dissolve in the lithography solvent.
Therefore, Patent Document 1 proposes a method of obtaining a polymer solution by dissolving a collected polymer powder in an organic solvent without drying, and then concentrating the powder.

In Patent Document 2, the recovered polymer wet powder is dried in a constant rate drying region to reduce the liquid content to 10% or less, and then the obtained dried product is dissolved in a low-boiling solvent, and further used for resist. A method of solvent replacement by dissolving in a solvent is described.
In Patent Document 3, the recovered polymer wet powder is washed with a washing solvent, optionally dried, and then dissolved in a resist solvent, and then cooled to about 50 ° C. to 15 ° C. An example is described in which a resist solvent is added, mixed and then heated and dissolved at 50 ° C.

JP 2006-161052 A JP 2010-14906 A JP 2010-204306 A

However, according to the knowledge of the present inventors, it takes a long time to dissolve the polymer wet powder in a good solvent for the polymer without drying it. On the other hand, when the polymer wet powder is dried to a liquid content of 10% or less and then dissolved in a good solvent for the polymer as described in Patent Document 2, the dissolution time is longer than when dissolving the wet powder. It can be shortened, but it takes a long time to dry. In the method described in Patent Document 3, it is necessary to cool the resist solvent, and heating is required to dissolve the wet powder in the resist solvent.
The present invention has been made in view of the above circumstances, and does not require solvent cooling or heating during dissolution, and can reduce the total process passing time of drying time and dissolution time. It is an object to provide a manufacturing method, a manufacturing method of a resist composition using a polymer solution for lithography obtained by the manufacturing method, and a manufacturing method of a substrate on which a pattern is formed using the resist composition. .

  In order to solve the above-mentioned problems, the method for producing a polymer solution for lithography according to the present invention is a polymerization in which a polymerization initiator is used to radically polymerize a monomer to obtain a polymerization reaction solution in the presence of a polymerization solvent. A step of mixing the polymerization reaction solution with a poor solvent for the polymer, and depositing the polymer to obtain a precipitate; and the solid content of the precipitate is in the range of 65 to 90% by mass. A fine drying step of obtaining a fine dry powder and a dissolution step of dissolving the fine dry powder in a good solvent for the polymer. In the dissolution step, the temperature of the fine dry powder is 0. It is -45 degreeC, The temperature of the said good solvent is 0-40 degreeC, It is characterized by the above-mentioned.

  Moreover, it is preferable that the quantity of the poor solvent contained in the fine dry powder obtained at the said fine dry process is 30 mass% or less.

It is preferable to have a concentration step of concentrating the solution obtained in the dissolution step.
It is preferable to have a filtration step of filtering the solution obtained in the dissolution step or the concentrate obtained in the concentration step.

  The present invention includes a step of producing a polymer solution for lithography by the method for producing a polymer solution for lithography of the present invention, a polymer solution for lithography obtained, and a compound that generates an acid upon irradiation with actinic rays or radiation. A method for producing a resist composition, comprising the step of mixing

  The present invention includes a step of producing a resist composition by the method for producing a resist composition of the present invention, a step of coating the obtained resist composition on a work surface of a substrate to form a resist film, and the resist Provided is a method for manufacturing a substrate on which a pattern is formed, which includes a step of exposing a film and a step of developing the exposed resist film using a developer.

The method for producing a polymer solution for lithography according to the present invention does not require heating during solvent cooling or dissolution, and can shorten the total process passing time of drying time and dissolution time.
Production efficiency is improved by reducing the process passage time.
Moreover, the solubility to a solvent can be improved, suppressing the heat history given to the polymer for lithography. Thereby, the sensitivity and the development contrast when the polymer for lithography is used for the resist composition can be improved.
According to the method for producing a resist composition of the present invention, a resist composition including the polymer for lithography produced by the production method of the present invention and excellent in sensitivity and development contrast can be obtained.
According to the substrate manufacturing method of the present invention, a highly accurate fine resist pattern can be stably formed using a resist composition having excellent sensitivity and development contrast.

<Polymer for lithography>
The polymer for lithography of the present invention preferably has a structural unit having a polar group.
[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.
In the present specification, “(meth) acrylic acid” means acrylic acid or methacrylic acid, and “(meth) acryloyloxy” means acryloyloxy or methacryloyloxy.

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.

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.
Examples of the resist polymer include a copolymer containing one or more of the structural units having the acid-eliminable group and one or more of the structural units having the polar group.

Examples of the polymer for antireflection film include a structural unit having a light-absorbing group and an amino group, an amide group, a hydroxyl 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, an anthracene ring or an anthracene ring having an arbitrary substituent is preferable, and when ArF laser light is used, a benzene ring or a benzene having an arbitrary substituent A ring is preferred.
Examples of the optional substituent 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, specifically, a copolymer of hydroxystyrene and a monomer such as styrene, alkyl (meth) acrylate, or 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.

<Method for producing polymer solution>
The method for producing a polymer solution for lithography according to the present invention generally includes a polymerization step of polymerizing monomers to obtain a polymerization reaction solution, a recovery step of depositing a polymer from the polymerization reaction solution to obtain a precipitate, The target polymer was dissolved in the solvent through a fine drying step of drying the precipitate to a specific solid content to obtain a fine dry powder and a dissolution step of dissolving the fine dry powder in a good solvent. This is a method for obtaining a polymer solution.
[Polymerization process]
A solution polymerization method is used as the polymerization method. That is, the polymerization reaction solution is obtained by radical polymerization of the monomer using a polymerization initiator in the presence of a polymerization solvent.
In the solution polymerization method, the monomer and the polymerization initiator may be supplied to the polymerization vessel either continuously or dropwise. As a solution polymerization method, a monomer and a polymerization initiator are dropped into a polymerization vessel from the viewpoint that a variation in average molecular weight and molecular weight distribution due to differences in production lots is small and a reproducible polymer can be easily obtained. The dropping polymerization method is preferred.

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 rate may be constant until the end of dropping, or may be changed in multiple stages according to the consumption rate of the monomer or the polymerization initiator.
The dripping may be performed continuously or intermittently.
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.

[Recovery process]
The polymerization reaction solution obtained in the polymerization step is mixed with a poor solvent to precipitate a polymer to obtain a precipitate. This technique is called a reprecipitation method, and is effective for removing unreacted monomers, polymerization initiators and the like remaining in the polymerization reaction solution. If the unreacted monomer remains as it is, the sensitivity decreases when used as a resist composition, so it is preferable to remove it as much as possible. The monomer content as an impurity in the polymer obtained by the production method of the present invention is more preferably 2.0% by mass or less, further preferably 1.0% by mass or less, and particularly preferably 0.29% by mass or less. 0.25% by mass or less is most preferable.
The poor solvent is a solvent that has a small ability to dissolve the target polymer and from which the polymer can precipitate. According to the composition of the polymer, known ones can be appropriately selected and used. Methanol, isopropyl alcohol, diisopropyl ether, heptane, or water is preferable because unreacted monomers, polymerization initiators, and the like used in the lithography polymer can be efficiently removed. A poor solvent may be used individually by 1 type, and may use 2 or more types together.

  In the recovery step, the polymerization reaction solution is preferably dropped into a poor solvent to precipitate the polymer in the polymerization reaction solution. The amount of the poor solvent when the polymerization reaction solution is dropped into the poor solvent is not particularly limited, but is preferably equal to or more than that of the diluted solution in terms of easier reduction of unreacted monomers, and is 3 on a mass basis. Is preferably 4 times or more, more preferably 4 times or more, still more preferably 5 times or more, and particularly preferably 6 times or more. The upper limit is not particularly limited, but if it is too much, the working efficiency in the subsequent filtration 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 dilution solvent include 1,4-dioxane, acetone, THF, MEK, MIBK, γ-butyrolactone, PGMEA, PGME, and ethyl lactate. 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.

In the recovery step, the target polymer is obtained in the form of a wet powder by filtering the precipitate deposited in the poor solvent.
Alternatively, the target polymer precipitate can be obtained by repeating the operation of dispersing the filtered wet powder again in a poor solvent and then filtering it. This process is referred to as “librarian” and is effective for further reducing impurities such as unreacted monomers and polymerization initiator remaining in the wet powder.
From the viewpoint that the polymer can be obtained while maintaining high productivity, it is preferable to recover the polymer precipitate only by the reprecipitation method without performing the rethrowing.

[Slight drying process]
In the present invention, the precipitate obtained in the recovery step is dried until a predetermined solid content is obtained to obtain a finely dried powder. That is, the wet powder obtained by filtering after re-precipitation in the recovery step, or the wet powder obtained by filtering after performing re-precipitation and re-laxing is dried. When the solid content is 65% by mass or more, the solubility in a solvent is remarkably improved. When the solid content exceeds 90% by mass, the time required for drying is remarkably increased. In particular, the preferable range of the solid content is 75 to 90% by mass in that the re-dissolution time in the dissolution step is short and the occupation ratio of the used kettle can be reduced.

  Moreover, the amount of the poor solvent contained in the fine dry powder obtained in the fine drying step is preferably 30% by mass or less. When it is 30% by mass or less, the solubility in a solvent is remarkably improved. Moreover, the lower limit of the amount of the poor solvent contained in the fine dry powder is not particularly limited, but is preferably 10% by mass or more. When the content is less than 10% by mass, the polymer powder for lithography is fused with each other during fine drying, and the dissolution time in the solvent may be prolonged.

Any drying method may be used as long as the wet powder can be dried to have a predetermined solid content, and a known drying method can be used. A vacuum drying method in which the pressure is reduced under a dry atmosphere, a heat drying method in which the heat is dried in a dry atmosphere, or a vacuum heat drying method in which the pressure is reduced and heated in a dry atmosphere is preferable, particularly in terms of drying in a shorter time. The method is preferred.
The degree of pressure reduction when the pressure is reduced is preferably 50 kPa or less, more preferably 40 kPa or less, and further preferably 30 kPa or less. The lower limit value of the degree of decompression is not particularly limited, but is practically 0.01 kPa or more.
When heating, the heating temperature is preferably 30 ° C. or higher, more preferably 35 ° C. or higher, and further preferably 40 ° C. or higher. The upper limit of the heating temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and further preferably 80 ° C. or lower in terms of preventing thermal deterioration of the polymer.

[Dissolution process]
The fine dry powder having a temperature of 0 to 45 ° C. obtained in the fine drying step is dissolved in a good solvent having a temperature of 0 to 40 ° C. Thereby, a solution in which the target polymer is dissolved in a good solvent is obtained.
As the good solvent, a known solvent capable of dissolving the target polymer can be used, and the solvents mentioned above as the polymerization solvent can be used. When the target polymer is used for the production of a resist composition, the same solvent as the resist solvent in the resist composition is preferably used as a good solvent in the dissolution step.
In the present invention, dissolving in a good solvent at a temperature of 0 to 40 ° C. means, for example, dissolving in a good solvent that has reached a constant temperature at a predetermined room temperature (atmospheric temperature) without actively cooling or heating. It means that The room temperature (atmosphere temperature) is 0 to 40 ° C, preferably 16 to 30 ° C.
The temperature of the fine dry powder immediately before mixing the fine dry powder with a good solvent is preferably 0 to 45 ° C, more preferably 16 to 40 ° C, and constant temperature at the predetermined room temperature (atmosphere temperature). It is particularly preferred that this is reached. In other words, the absolute value of the temperature difference between the finely-dried powder to be mixed and the good solvent is preferably smaller in that it does not require active cooling or heating. Specifically, the absolute value of the temperature difference is preferably 30 ° C. or less, more preferably 20 ° C. or less, and particularly preferably 15 ° C. or less.
Further, when the fine dry powder is dissolved in a good solvent, additives such as a storage stabilizer may be added as appropriate. That is, the polymer solution may contain an additive such as a storage stabilizer.

[Concentration process]
The solution obtained in the dissolving step may be concentrated to obtain a concentrated solution in which the target polymer is dissolved in a good solvent. By performing the concentration, the remaining low-boiling compounds can be removed.
A known concentration method can be used. It is preferable to concentrate under reduced pressure because it can be concentrated in a short time. The degree of reduced pressure in the case of concentration under reduced pressure is preferably 50 kPa or less, more preferably 40 kPa or less, and further preferably 30 kPa or less. The lower limit value of the degree of decompression is not particularly limited, but is actually 0.05 kPa or more.
In addition, heating during vacuum concentration is also preferable because it can be concentrated in a short time. As heating temperature, 20 degreeC or more is preferable, 30 degreeC or more is more preferable, and 40 degreeC or more is further more preferable. In addition, the heating temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and further preferably 80 ° C. or lower in terms of preventing thermal degradation of the polymer.
During the concentration, it is preferable to carry out stirring while preventing bumping. In addition, it is preferable to concentrate in a pressure-resistant metal reaction vessel in that pressure control is possible and heat conductivity is excellent and reaction temperature control is facilitated. As the metal, stainless steel (hereinafter also referred to as SUS) is preferable because it has high corrosion resistance and can reduce the mixing of metal impurities into the polymer.

[Filtering process]
The solution obtained in the dissolution step or the concentrate obtained in the concentration step may be filtered as necessary. As a result, a polymer solution with reduced polymer gel and foreign matter can be obtained.
In view of the fact that the pressure loss before and after the filtration filter can be kept low and the filtration can be performed in a short time, it is preferable to filter the solution obtained in the dissolution step before the concentration step.
In terms of efficiently reducing polymer gels and foreign substances that may be mixed into the final product, it is preferable to filter the obtained concentrated solution after the concentration step.
Both the solution obtained in the dissolving step and the concentrated solution may be filtered. That is, after filtering the solution obtained in the dissolution step, the obtained filtrate may be subjected to the concentration step and concentrated, and the resulting concentrated solution may be further filtered.

<Method for producing resist composition>
The method for producing a resist composition of the present invention includes a step of producing a solution (polymer solution) in which a target polymer is dissolved by the production method of the present invention, the obtained polymer solution, and irradiation with actinic rays or radiation. And a step of mixing with a compound generating an acid. If necessary, a resist solvent is further added and mixed. As the resist solvent, the solvents listed above as the polymerization solvent can be used. The resist composition thus obtained is a chemically amplified resist composition.
The polymer solution used in the production of the resist composition may be the solution obtained in the dissolution step, the filtrate filtered thereafter, the concentrate obtained in the concentration step, or the filtrate filtered thereafter. .

[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 may contain various additives such as a surfactant, 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 the 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).

<Solid content of wet powder before fine drying and fine dry powder after fine drying>
Weigh 1.0 g of the powder to be measured in an aluminum dish, weigh the mass after drying at 150 ° C. for 3 hours under normal pressure, calculate the following formula, and calculate the solid content [unit: mass%] Is calculated. The mass [g] before drying is 1.0 (g).
Solid content [mass%] = mass after drying [g] / mass before drying [g] × 100

<Evaluation of residual solvent>
The residual solvent in the polymer was determined by an internal standard method by gas chromatography under the following conditions (GC conditions).
[GC condition]
Apparatus: Agilent Technologies, Inc., Agilent Technologies 6890 (trade name),
Carrier gas: He,
Total flow rate: 24 mL / min,
Separation column: HP-INNWAX (trade name), manufactured by Agilent Technologies, Inc., length 30 m × inner diameter 0.32 mm × film thickness 0.25 μm,
Column flow rate: 1.5 mL / min (40 ° C.)
Column heating conditions: 50 ° C. (holding for 10 minutes) → (heating at 10 ° C./min)→110° C. (holding for 9 minutes),
Inlet temperature: 230 ° C
Detection port temperature: 230 ° C.
Detector: Hydrogen flame ionization detector (FID)
Injection volume: 1 μL
Sample: 0.1 mL of the polymer was added with 5 mL of acetonitrile and allowed to stand at 25 ° C. for 12 hours. Then, 0.98 mL of the supernatant was collected, and 20 μL of 1% solution of n-butyl alcohol as an internal standard was collected. Added solution.

<Evaluation of solubility>
200 g of the obtained fine dry powder was dissolved in 2000 g of PGMEA. The time from the start of dissolution until complete dissolution was observed as the redissolution time [unit: hours].

<Measurement of light transmittance of polymer film>
A PGMEA solution containing 19% by mass of the polymer to be measured in solid content concentration was prepared and filtered through a membrane filter having a pore size of 0.1 μm to prepare a polymer solution. The prepared polymer solution was spin-coated on a quartz wafer and pre-baked at 120 ° C. for 60 seconds using a hot plate to produce a 1.0 μm-thick polymer film.
The polymer film produced on the quartz wafer was placed on the sample side, and the untreated quartz wafer was placed on the reference side, respectively, and the wavelength was measured using an ultraviolet / visible absorptiometer UV-3100 (trade name) manufactured by Shimadzu Corporation. Measurement was carried out with the range set to 192 to 194 nm, the scan speed set to medium speed, the sampling pitch set to automatic, and the slit width set to 2.0 to determine the light transmittance (%) at 193 nm.

<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 dose-residual film rate curve) is prepared, and Eth sensitivity (required exposure amount for setting the remaining film rate to 0%, which represents sensitivity) and γ value (exposure dose-residual film rate curve). (Denoting the development contrast). The smaller the Eth sensitivity value, the higher the sensitivity of the resist composition, and the larger the γ value, the better the development contrast.
Eth sensitivity: exposure amount (mJ / cm ² ) at which the exposure amount-residual film rate curve intersects with a residual film rate of 0%.
γ value: E50 (mJ / cm ² ) exposure amount at 50% of the remaining film rate of the exposure amount-residual film rate curve, and a tangent line at E50 of the exposure amount-residual film rate curve is a straight line with a remaining film rate of 100% The exposure amount intersecting with the straight line having a film rate of 0% was determined as E100 and E0, respectively, and the following formula was used.
γ = 1 / {log (E0 / E100)}

<Example 1>
243.6 g of ethyl lactate was placed in a 1 L SUS flask 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 the hot water bath 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.
[Mixture 1]
95.20 g of a monomer of the following formula (m1),
131.04 g of a monomer of the following formula (m2),
66.08 g of a monomer of the following formula (m3),
438.5 g of ethyl lactate,
8.649 g of dimethyl-2,2′-azobisisobutyrate (manufactured by Wako Pure Chemical Industries, Ltd., V601 (trade name)).
The charge ratio (mol%) of each monomer is shown in Table 1. The viscosity at 25 ° C. of the obtained polymerization reaction solution was measured. The results are shown in Table 1.

The obtained polymerization reaction solution was dropped into 7.0 times the amount of a poor solvent while stirring the poor solvent to precipitate a polymer (white precipitate). As a poor solvent, a mixed solvent of methanol and water (methanol / water = 95/5 volume ratio) was used.
The precipitate was filtered off to obtain 516 g of wet powder. The wet powder was finely dried under the fine drying conditions shown in Table 1 (pressure [unit: kPa], drying temperature [unit: ° C.], drying time [unit: time]) to obtain a fine dry powder. The moisture content before fine drying, the solid content of the fine dry powder obtained, and the residual solvent composition of the fine dry powder were measured. The results are shown in Table 1.
Next, 200 g of the fine dry powder (29 ° C.) obtained above was dissolved in 2000 g of PGMEA (25 ° C.) in an atmosphere at 25 ° C. At this time, the re-dissolution time was measured by the above method. The results are shown in Table 1.

Next, the obtained solution was filtered through a cartridge filter made of nylon having a pore size of 0.04 μm. The obtained filtrate was concentrated under the conditions of a pressure of 20 kPa and a temperature of 50 ° C., and when the distillate no longer came out, the pressure was changed to 3 kPa and a temperature of 65 ° C., so that the solid content concentration of the polymer was 25% by mass. Concentration was performed until
About 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 2.
Moreover, the light transmittance of the polymer film was measured by the above method using the obtained concentrated liquid (PGMEA solution). The results are shown in Table 2.

[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 is added, and further PGMEA as a solvent is added so that the polymer concentration becomes 12.5% by mass and mixed. After preparing a uniform solution, the solution was filtered through a membrane filter having a pore size of 0.1 μm to obtain a resist composition. Eth sensitivity and γ value of the obtained resist composition were measured by the above methods. The results are shown in Table 2.

<Examples 2, 3, 4 and Comparative Examples 1, 2>
The same procedure as in Example 1 was performed except that the drying conditions were changed as shown in Table 1. The results are shown in Tables 1 and 2.

<Example 5>
In this example, a monomer of the following formula (m4) was used in place of the monomer of the formula (m2) in Example 1.
That is, 225.9 g of ethyl lactate was placed in the same flask as in Example 1. The inside of the flask was replaced with nitrogen, and the flask was placed in a hot water bath while maintaining the nitrogen atmosphere, and the temperature of the hot water bath was raised to 80 ° C. while stirring the inside of the flask.
Thereafter, the following mixture 2 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.
[Mixture 2]
95.20 g of a monomer of the following formula (m1),
66.08 g of a monomer of the following formula (m3),
109.76 g of a monomer of the following formula (m4),
406.6 g of ethyl lactate,
8.372 g of dimethyl-2,2′-azobisisobutyrate (said V601 (trade name)).
The charge ratio (mol%) of each monomer is shown in Table 1.

The obtained polymerization reaction solution was dropped into 7.0 times the amount of a poor solvent while stirring the poor solvent to precipitate a polymer (white precipitate). As a poor solvent, a mixed solvent of methanol and water (methanol / water = 80/20 volume ratio) was used.
The precipitate was filtered off to obtain 684 g of wet powder. The wet powder was finely dried under the fine drying conditions shown in Table 1 to obtain a finely dried powder. The moisture content before fine drying, the solid content of the fine dry powder obtained, and the residual solvent composition of the fine dry powder were measured. The results are shown in Table 1.
Next, 200 g of the fine dry powder (25 ° C.) obtained above was dissolved in 2000 g of PGMEA (20 ° C.) in an atmosphere of 20 ° C. At this time, the re-dissolution time was measured by the above method. The results are shown in Table 1.
Subsequently, the obtained solution was filtered through a cartridge filter made of nylon having a pore size of 0.02 μm. The obtained filtrate was concentrated in the same manner as in Example 1, and Mw and Mw / Mn were measured. The light transmittance of the polymer film was measured in the same manner as in Example 1. Resist compositions were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative Example 3>
The drying conditions were changed as shown in Table 1. The fine dry powder was dissolved in PGMEA to form a polymer solution, and then the concentration was performed without filtration. The others were performed in the same manner as in Example 5. The results are shown in Tables 1 and 2.

<Example 6>
In this example, monomers of the following formulas (m6) and (m5) were used in place of the monomers of the formulas (m2) and (m3) in Example 1.
That is, 161.0 g of ethyl lactate was placed in the same flask as in Example 1. The inside of the flask was replaced with nitrogen, and the flask was placed in a hot water bath while maintaining the nitrogen atmosphere, and the temperature of the hot water bath was raised to 80 ° C. while stirring the inside of the flask.
Thereafter, the following mixture 3 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.
[Mixture 3]
136.1 g of the monomer of the following formula (m1),
70.5 g of a monomer of the following formula (m5),
104.0 g of the monomer of the following formula (m6),
310.6 g of ethyl lactate,
16.56 g of dimethyl-2,2'-azobisisobutyrate (said V601 (trade name)).
The charge ratio (mol%) of each monomer is shown in Table 1.

The obtained polymerization reaction solution was diluted with ethyl lactate so that the mass became 1.5 times. Thereafter, the poor solvent was dropped into 10.0 times the poor solvent of the diluted polymerization reaction solution while stirring to precipitate a polymer (white precipitate). Diisopropyl ether was used as a poor solvent.
The precipitate was filtered off to obtain 508 g of wet powder. The wet powder was finely dried under the drying conditions shown in Table 1 to obtain a finely dried powder. The moisture content before fine drying, the solid content of the fine dry powder obtained, and the residual solvent composition of the fine dry powder were measured. The results are shown in Table 1.

Next, 200 g of the fine dry powder (16 ° C.) obtained above was dissolved in 2000 g of PGMEA (16 ° C.) in a 16 ° C. atmosphere to obtain a solution. At this time, the re-dissolution time was measured by the above method. The results are shown in Table 1.
Next, the obtained solution was filtered through a cartridge filter made of nylon having a pore size of 0.04 μm. The obtained filtrate (the polymer solution after filtration) was concentrated under the conditions of a pressure of 10 kPa and a temperature of 40 ° C., and when the distillate no longer came out, the pressure was changed to 5 kPa and the temperature of 55 ° C. Concentration was performed until the concentration reached 25% by mass.
The obtained concentrated solution was concentrated in the same manner as in Example 1, and Mw and Mw / Mn were measured.
Further, the light transmittance of the polymer film was measured in the same manner as in Example 1. The results are shown in Table 2. Since the light transmittance at 193 nm is low and the absorbance is large, it was found that the film can be used as an antireflection film for ArF lithography. For this reason, the resist composition was not evaluated.

<Comparative example 4>
The drying conditions were changed as shown in Table 1. The fine dry powder was dissolved in PGMEA to form a polymer solution, and then the concentration was performed without filtration. The others were performed in the same manner as in Example 6. The results are shown in Tables 1 and 2.

As shown in the results of Tables 1 and 2, Examples 1 to 4 in which the solid content of the fine dry powder is 65 to 90% by mass are Comparative Examples 1 in which the solid content of the fine dry powder is lower than this. As compared with, the re-dissolution time was significantly shortened, and the sensitivity and development contrast of the resist composition were improved. In addition, in the range where the solid content of the fine dry powder is 90% by mass or less, the re-dissolution time becomes shorter as the solid content of the fine dry powder becomes higher. When it exceeded, re-dissolution time became long on the contrary, and the comparative example 2 was inferior in the sensitivity and development contrast of the resist composition compared with Examples 1-4.
Similarly, when Example 5 and Comparative Example 3 are compared, Example 5 in which the solid content of the fine dry powder is 70% by mass is Comparative Example in which the solid content of the fine dry powder is 98% by mass. Compared to 3, the re-dissolution time was short, and the sensitivity and development contrast of the resist composition were improved.
Further, when Example 6 and Comparative Example 4 are compared, Example 6 in which the solid content of the fine dry powder is 67% by mass is Comparative Example 4 in which the solid content of the fine dry powder is 58% by mass. Compared with, re-dissolution time was significantly shortened.

Claims (6)

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 recovery step of mixing the polymerization reaction solution with a poor solvent for the polymer, precipitating the polymer, and obtaining a precipitate;
A fine drying step of drying the precipitate so that the solid content is in the range of 65 to 90% by mass to obtain a fine dry powder;
Dissolving the finely-dried powder in a good solvent for the polymer,
The method for producing a polymer solution for lithography, wherein in the dissolving step, the temperature of the fine dry powder is 0 to 45 ° C, and the temperature of the good solvent is 0 to 40 ° C.   The manufacturing method of the polymer solution for lithography of Claim 1 whose quantity of the poor solvent contained in the fine dry powder obtained at the said fine drying process is 30 mass% or less.   The manufacturing method of the polymer solution for lithography of Claim 1 or 2 which has a concentration process which concentrates the solution obtained by the said melt | dissolution process.   The manufacturing method of the polymer solution for lithography as described in any one of Claims 1-3 which has a filtration process which filters the solution obtained at the said melt | dissolution process, or the concentrate obtained at the said concentration process.   A step of producing a polymer solution for lithography by the production method according to any one of claims 1 to 4, a polymer solution for lithography obtained, and a compound that generates an acid upon irradiation with actinic rays or radiation, A method for producing a resist composition, which comprises a step of mixing.   A step of producing a resist composition by the production method according to claim 5, a step of applying the obtained resist composition onto a work surface of a substrate to form a resist film, and the resist film, A method for producing a substrate on which a pattern is formed, comprising a step of exposing and a step of developing the exposed resist film using a developer.