JP5362177B2 - Method for producing polymer wet powder for resist - Google Patents

Description

The present invention relates to the production how the resist polymer Shimekona.

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

  As a resin for a chemically amplified resist composition used in the formation of a resist pattern using an ArF excimer laser (wavelength 193 nm), an acrylic polymer that is transparent to light with a wavelength of 193 nm has attracted attention. As the polymer, for example, a polymer of (meth) acrylic acid ester having an alicyclic skeleton and (meth) acrylic acid ester having a lactone skeleton is known (Patent Documents 1 and 2).

The polymer is produced through the following steps (Examples of Patent Documents 1 and 2).
(I) A step of polymerizing a monomer component containing a (meth) acrylic acid ester having an alicyclic skeleton, a (meth) acrylic acid ester having a lactone skeleton, and the like by a solution polymerization method.
(Ii) A step of pouring the polymer solution obtained by the solution polymerization method into a poor solvent to precipitate the polymer to obtain a polymer dispersion.
(Iii) A step of recovering the polymer powder by filtering the polymer dispersion using a filter.
(Iv) A step of dissolving the collected polymer powder in a good solvent to obtain a polymer solution, pouring the polymer solution into a poor solvent to precipitate the polymer, and obtaining a polymer dispersion.
(V) A step of filtering the polymer dispersion using a filter to recover the polymer powder.
(Vi) A step of drying the recovered polymer powder after repeating the steps (iv) to (v) as necessary.

However, when the polymer obtained by this method is dissolved in a solvent for resist, undissolved residue may occur. This phenomenon is particularly likely to occur in summer when the temperature is high. When the undissolved residue occurs, a development defect called a defect occurs during development of a resist film made of the resist composition containing the polymer, and the defect causes a loss of the resist pattern. A disconnection, a defect, etc. occur in the formed circuit.
JP 10-319595 A JP-A-10-274852

  The present invention provides a polymer powder having good solubility in a solvent, a polymer wet powder having good solubility in a solvent, a method for producing the same, and a resist composition capable of suppressing the occurrence of defects in a resist pattern.

The method for producing a resist polymer wet powder according to the present invention includes a step of filtering a dispersion in which a resist polymer is dispersed in a dispersion medium to produce a resist polymer wet powder, and the produced resist polymer. A method for producing a polymer powder for resist having a step of storing the powder, characterized in that the polymer powder for resist is stored in an environment controlled so that the air temperature is always 35 ° C. or lower. And
The glass transition temperature of the resist polymer is preferably 125 to 150 ° C.

According to the method for producing a polymer powder of the present invention, a polymer powder having good solubility in a solvent can be produced.
The polymer powder of the present invention is excellent in solubility in a solvent.
The polymer powder of the present invention has good solubility in a solvent.
The resist composition of the present invention can suppress the occurrence of defects in the resist pattern.

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

<Method for producing polymer wet powder>-
The method for producing a polymer wet powder of the present invention includes a step of producing a polymer wet powder by filtering a dispersion in which a polymer is dispersed in a dispersion medium.

(Dispersion)
Examples of polymers include acrylic polymers, styrene polymers (polystyrene, acrylonitrile-butadiene-styrene copolymers, etc.), vinyl chloride polymers, polyester polymers, cycloolefin polymers, vinyl ether polymers. And fluorine-based polymers.
Examples of the polymer include a resist polymer, a coating polymer, an antireflection polymer, and the like according to use.
The method for producing a polymer wet powder of the present invention is suitable for producing a resist polymer wet powder or a resist polymer powder that is required to reduce the amount of undissolved residue in a solvent as much as possible.

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

Examples of the dispersion liquid in which the polymer is dispersed in the dispersion medium include the following dispersion liquids.
(Α) A polymer dispersion obtained by pouring a polymer solution obtained by a solution polymerization method into a poor solvent to precipitate the polymer.
(Β) A polymer slurry obtained by coagulating a polymer in a latex obtained by an emulsion polymerization method.
(Γ) A suspension of a polymer obtained by suspension polymerization.
(Δ) A dispersion obtained by pulverizing a polymer obtained by bulk polymerization and dispersing in a dispersion medium.
(Ε) A dispersion in which the polymer recovered from (α) to (δ) is dispersed again in a dispersion medium.

(Polymer wet powder)
The polymer wet powder is a polymer containing a dispersion medium obtained by filtering a dispersion.
In the present invention, when the produced polymer powder is stored, the polymer powder is stored in an environment controlled so that the air temperature is always 35 ° C. or lower. By storing polymer wet powder in an environment controlled so that the air temperature is always 35 ° C. or lower, it is difficult for the polymer wet powder to bind to each other, and the solubility in the solvent is reduced. Can do. In addition, by storing the polymer powder in an environment controlled so that the air temperature is always 35 ° C. or less, the polymer powder obtained by drying the polymer powder becomes difficult to bind, It can suppress that the solubility to the solvent of a polymer powder falls. The temperature is preferably 20 ° C. or lower, more preferably 10 ° C. or lower, and particularly preferably 5 ° C. or lower. The temperature is preferably equal to or higher than the freezing point of the dispersion medium.

  The environment controlled so that the air temperature is always 35 ° C. or lower includes a refrigerator (refrigeration room) having a temperature adjustment function, a thermostat (temperature bath) having a temperature adjustment function, an air conditioning room having an air conditioning facility, a temperature A constant temperature and humidity chamber (a constant temperature and humidity chamber) provided with an adjustment function and a humidity adjustment function can be used, and the inside of the refrigerator (refrigeration room) is preferable from the viewpoint of easily maintaining the temperature at a low temperature.

  In the present invention, when the produced polymer powder is stored for 1 hour or longer, it is preferable to store the polymer powder in an environment controlled so that the temperature is always 35 ° C. or lower. When the produced polymer powder is stored for 1 hour or more in an environment where the temperature exceeds 35 ° C., the polymer powder becomes easy to bind to each other, and the solubility of the polymer in the solvent decreases.

In the present invention, when a polymer powder having a glass transition temperature of 60 to 150 ° C. is stored, the polymer powder may be stored in an environment controlled so that the air temperature is always 35 ° C. or lower. preferable. When the polymer powder having a glass transition temperature of 60 to 150 ° C. is stored in an environment where the temperature exceeds 35 ° C., the polymer powder tends to bind to each other, and the solubility of the polymer in the solvent decreases. To do.
The glass transition temperature of a polymer is a temperature at which it transitions from a glassy state to a rubbery state. When the polymer is heated from room temperature at a rate of 10 ° C./minute, heat is generated by a differential scanning calorimeter. It is obtained by measuring the amount. Specifically, two extension lines are drawn on the endothermic curve (exothermic curve), and are obtained from the intersection of the 1/2 straight line between the extension lines and the endothermic curve.

  In the present invention, when storing a polymer powder containing 10 to 400 parts by mass of a dispersion medium with respect to 100 parts by mass of the polymer, the polymer is used in an environment controlled so that the temperature is always 35 ° C. or lower. It is preferable to store the wet powder. When the polymer powder containing 10 to 400 parts by mass of the dispersion medium with respect to 100 parts by mass of the polymer is stored in an environment where the temperature exceeds 35 ° C., the polymer powders are easily bound to each other. Solubility in the solvent decreases.

(Method for producing resist polymer)
Hereinafter, a method for producing a resist polymer will be specifically described.
The resist polymer is manufactured through the following steps, for example.
(A) A step of polymerizing the monomer component.
(B) A step of obtaining a polymer dispersion.
(C) A step of producing a polymer wet powder by filtering the polymer dispersion.
(D) A step of dispersing the produced polymer wet powder in a poor solvent to obtain a polymer dispersion.
(E) A step of producing a polymer powder by filtering the polymer dispersion using a filter.

The manufactured polymer powder is subjected to the following step (f) or (g), and then the final product is obtained through steps (h) and (i).
(F) A step of drying the produced polymer wet powder to obtain a polymer powder and then dissolving it in a good solvent to obtain a polymer solution.
(G) A step of dissolving the produced polymer wet powder in a good solvent to obtain a polymer solution.
(H) A step of removing impurities by passing the polymer solution through a precision filter.
(I) A step of removing the remaining poor solvent from the polymer solution that has passed through the precision filter, and further concentrating the polymer solution.

(A) Process:
Examples of the polymerization method include known polymerization methods such as a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and a bulk polymerization method. In order not to reduce the light transmittance, a monomer remaining after the completion of the polymerization reaction is used. The solution polymerization method is preferable because it needs to be removed and the molecular weight of the polymer needs to be relatively low. Among the solution polymerization methods, the monomer component was heated to a predetermined polymerization temperature from the standpoint of easily obtaining a reproducible polymer with small variations in average molecular weight and molecular weight distribution due to differences in production lots. A polymerization method called a dropping polymerization method in which the polymerization vessel is dropped into a polymerization vessel is preferable.

Polymerization of the monomer component by the drop polymerization method is performed, for example, as follows.
A raw material (a monomer component, a polymerization initiator, a solvent, etc.) is poured into a blending tank 10 having a stirrer 12 and a jacket 14 shown in FIG. 1 and stirred with the stirrer 12 to prepare a monomer solution.
A solvent is poured into a polymerization tank 20 having a stirrer 22, a jacket 24, and a condenser 26, and kept at a constant temperature. The monomer solution in the preparation tank 10 is supplied to the polymerization tank 20 by the pump 102 and dropped into a solvent maintained at a constant temperature to polymerize the monomer components to obtain a polymer solution.

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

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

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

Examples of the monomer (1) having a lactone skeleton include known monomers used in the production of resist polymers, and resists using ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm). In view of obtaining a polymer suitable for pattern formation, a (meth) acrylic acid ester having a lactone skeleton is preferred.
As the (meth) acrylic acid ester having a lactone skeleton, monomers (1-1) to (1-10) are preferable. However, R represents a hydrogen atom or a methyl group.

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

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

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

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

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

Examples of the monomer (2) having an acid leaving group include known monomers used for the production of resist polymers. ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) is used. A (meth) acrylic acid ester having an acid leaving group is preferred from the viewpoint of obtaining a polymer suitable for forming the used resist pattern.
As the (meth) acrylic acid ester having an acid leaving group, monomers (2-1) to (2-38) are preferable. However, R represents a hydrogen atom or a methyl group.

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

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

Examples of the monomer (3) having a hydrophilic group include known monomers used for the production of resist polymers, and an ArF excimer laser (wavelength 193 nm) or a KrF excimer laser (wavelength 248 nm) was used. In view of obtaining a polymer suitable for forming a resist pattern, a (meth) acrylic acid ester having a hydrophilic group is preferred.
As the (meth) acrylic acid ester having a hydrophilic group, monomers (3-1) to (3-6) are preferable. However, R represents a hydrogen atom or a methyl group.

The monomer (4) having a nonpolar alicyclic skeleton (except for a monomer having a lactone skeleton, a monomer having an acid-eliminable group, and a monomer having a hydrophilic group), It is a component that improves the dry etching resistance of the resist pattern.
The amount of the monomer (4) having a nonpolar alicyclic skeleton is preferably 20 mol% or less in the monomer component (100 mol%). As the monomer (4) having a nonpolar alicyclic skeleton, one type may be used alone, or two or more types may be used in combination.

Examples of the monomer (4) having a nonpolar alicyclic skeleton include known monomers used in the production of resist polymers, such as ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm). (Meth) acrylic acid ester having a nonpolar alicyclic skeleton is preferable from the viewpoint of obtaining a polymer suitable for forming a resist pattern using.
Examples of the (meth) acrylic acid ester having a nonpolar alicyclic skeleton include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, adamantyl (meth) acrylate, (meth) Examples include tricyclodecanyl acrylate and dicyclopentadienyl (meth) acrylate. The (meth) acrylic acid ester having a nonpolar alicyclic skeleton may have a linear or branched alkyl group having 1 to 6 carbon atoms on the alicyclic skeleton.
As the (meth) acrylic acid ester having a nonpolar alicyclic skeleton, monomers (4-1) to (4-2) are preferable. However, R represents a hydrogen atom or a methyl group.

Examples of other monomer (5) include methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Isopropyl, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2, (meth) acrylic acid 2, 2,3,3-tetrafluoro-n-propyl and the like can be mentioned.
The amount of the other monomer (5) is preferably 20 mol% or less in the monomer component (100 mol%). Another monomer (5) may be used individually by 1 type, and may be used in combination of 2 or more type.

As the polymerization initiator, those that generate radicals efficiently by heat are preferable. Examples of such a polymerization initiator include azo compounds such as 2,2′-azobisisobutyronitrile and dimethyl-2,2′-azobisisobutyrate; 2,5-dimethyl-2,5- And organic peroxides such as bis (tert-butylperoxy) hexane.
As for the quantity of a polymerization initiator, 1-20 mol% is preferable with respect to a monomer component (100 mol%).

As the solvent, when a monomer component, a polymerization initiator, a polymer to be obtained, and a chain transfer agent are used in combination, a solvent that can dissolve all of the chain transfer agent is preferable. Examples of the solvent include 1,4-dioxane, isopropyl alcohol, acetone, tetrahydrofuran, methyl isobutyl ketone, γ-butyrolactone, propylene glycol monomethyl ether acetate, ethyl lactate and the like.
The amount of the solvent is the total amount of the solvent contained in the monomer solution and the solvent initially injected into the polymerization tank 20, and is preferably 30 to 700 parts by mass with respect to the monomer component (100 parts by mass).

In the step (a), a chain transfer agent may be used. By using a chain transfer agent, a polymer having a low molecular weight and a small molecular weight distribution can be produced. Examples of the chain transfer agent include 1-butanethiol, 2-butanethiol, 1-octanethiol, 1-decanethiol, 1-tetradecanethiol, cyclohexanethiol, 2-methyl-1-propanethiol, 2-mercaptoethanol, Examples include mercaptoacetic acid and 1-thioglycerol.
As for the quantity of a chain transfer agent, 1-20 mol% is preferable with respect to a monomer component (100 mol%).

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

(B) Process:
The method for obtaining the polymer dispersion varies depending on the polymerization method in step (a).
In the case of the solution polymerization method (drop polymerization method), the dispersion liquid (α) is obtained by pouring the obtained polymer solution into a poor solvent to precipitate the polymer.
In the case of the emulsion polymerization method, the polymer slurry (β) is obtained by coagulating the polymer in the obtained latex by aciding out or salting out.
In the case of the suspension polymerization method, the obtained polymer suspension becomes the suspension (γ) as it is.
In the case of bulk polymerization, the obtained polymer is pulverized and then dispersed in a dispersion medium to obtain the dispersion liquid (δ).

When the polymer solution obtained by the solution polymerization method (drop polymerization method) is poured into a poor solvent to precipitate the polymer, it is performed as follows.
The polymer solution in the polymerization tank 20 shown in FIG. 1 is diluted with a good solvent to an appropriate solution viscosity as necessary.
A poor solvent is injected into a purification tank 30 having a stirrer 32 and a jacket 34. The polymer solution in the polymerization tank 20 is supplied to the purification tank 30 by the pump 104 and dropped into the poor solvent while stirring with the stirrer 32 to precipitate the polymer to obtain a polymer dispersion.

Examples of the good solvent include the solvent used in the step (a).
As a poor solvent, the poor solvent for the said resist polymer is mentioned.
The amount of the poor solvent is preferably 300 to 3000 parts by mass with respect to 100 parts by mass of the polymer solution.

(C) Process:
The polymer dispersion in the purification tank 30 shown in FIG. 1 is supplied to a vacuum filter 40 having a filter 42, and the polymer dispersion is filtered using the filter 42 to produce a polymer wet powder.
Examples of the filter 42 include a filter cloth, a filter paper, and a glass filter, and industrially a filter cloth is preferable. The filter cloth is a cloth woven from long fibers. Examples of the long fiber material include polyester and nylon.
The filter 42 may be a filter obtained by washing the filter used in the previous lot, or may be a new filter that has never been used for filtration.

Instead of a vacuum filter, a pressure filter, a centrifugal dehydrator, a gravity filter, a centrifuge, or the like may be used. Two or more of these may be used in combination.
When the produced polymer powder is stored, the polymer powder is stored in an environment (for example, in the refrigerator 44) controlled so that the air temperature is always 35 ° C. or lower.

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

(E) Process:
In the same manner as in step (c), the polymer dispersion is filtered using a filter 42 to produce a polymer wet powder.
As the filter 42, the filter used in the step (c) may be used as it is, or another filter may be newly prepared and used instead of the filter used in the step (c).
When the produced polymer powder is stored, the polymer powder is stored in an environment (for example, in the refrigerator 44) controlled so that the air temperature is always 35 ° C. or lower.

(F) Process:
The polymer wet powder produced in the step (e) is transferred to a drier (not shown), and the damp powder is dried by the drier to obtain a polymer powder.
Examples of the dryer include a vacuum dryer.
The drying temperature is preferably 20 to 100 ° C.
The drying time is preferably 2 to 200 hours.

(G) Process:
A good solvent is poured into a dissolution tank 50 having a stirrer 52 and a jacket 54 shown in FIG. The polymer wet powder produced in the step (e) is charged into the dissolution tank 50, stirred with a stirrer 52 and dissolved in a good solvent to obtain a polymer solution.
As a good solvent, the solvent for the below-mentioned resist composition is mentioned.
The amount of the good solvent is preferably 100 to 5000 parts by mass with respect to 100 parts by mass of the polymer.

(H) Process:
1, the polymer solution in the dissolution tank 50 is supplied to a microfilter 60 having a precision filter 62, and the polymer solution is passed through the precision filter 62 to remove impurities.
Examples of the precision filter 62 include a membrane filter and a cartridge filter.

(I) Process:
The polymer solution that has passed through the precision filter 62 is injected into the concentration tank 70 having the stirrer 72, the jacket 74, and the condenser 76 shown in FIG. The polymer solution in the concentration tank 70 is heated by the jacket 74 while being stirred by the stirrer 72, the remaining poor solvent is removed from the polymer solution, and the polymer solution is further concentrated to a predetermined polymer concentration. A polymer solution (resist composition) as a final product is obtained.
The poor solvent and the vapor of the good solvent discharged from the concentration tank 70 are condensed into a liquid by the condenser 76 and sent to the recovery tank 80.

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

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

The solvent for the resist composition is arbitrarily selected according to use conditions and the like.
Examples of the solvent include linear or branched ketones such as methyl ethyl ketone, methyl isobutyl ketone and 2-pentanone; cyclic ketones such as cyclopentanone and cyclohexanone; propylene glycol monoalkyl acetates such as propylene glycol monomethyl ether acetate; Ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether; diethylene glycol alkyl ethers such as diethylene glycol dimethyl ether; Esters such as ethyl acetate and ethyl lactate; n-propylarco Le, isopropyl alcohol, n- butyl alcohol, tert- butyl alcohol; 1,4-dioxane, ethylene carbonate, .gamma.-butyrolactone. A solvent may be used individually by 1 type and may use 2 or more types together.
The amount of the solvent is usually 200 parts by mass or more and more preferably 300 parts by mass or more with respect to 100 parts by mass of the resist polymer. Moreover, the quantity of a solvent is 5000 mass parts or less with respect to 100 mass parts of resist polymers normally, and 2000 mass parts or less are more preferable.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  In the method for producing the polymer wet powder of the present invention described above, the temperature is always kept at 35 ° C. or lower when storing the polymer wet powder produced by filtering the polymer dispersion. Since the polymer powder is stored under the environment, a polymer powder having good solubility in a solvent can be produced. That is, the present inventors have found that the problem of undissolved residue when the polymer is dissolved in a solvent for resist is that the polymer wet powder binds during storage of the produced polymer wet powder. I found out that it occurred. Therefore, it was decided to store the polymer powder in an environment where the polymer powders are not bound to each other, that is, in an environment where the temperature is always 35 ° C. or lower.

Moreover, since the polymer wet powder of this invention is a polymer wet powder obtained by the manufacturing method of this invention, it is excellent in the solubility to a solvent.
Moreover, since the resist composition of the present invention is obtained from the polymer wet powder obtained by the production method of the present invention, the occurrence of defects in the resist pattern can be suppressed.

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

[Example 1]
(A) Process:
In a compounding tank having a stirrer and a jacket, 23.0 parts by mass (40 mol%) of monomer (1-1) (where R is a methyl group), monomer (2-8) (where R is Methyl group.) 26.5 parts by mass (40 mol%), monomer (3-2) (where R is a methyl group) 16.0 parts by mass (20 mol%), ethyl lactate 98.0 parts by mass Then, 2.33 parts of a polymerization initiator (manufactured by Wako Pure Chemical Industries, Ltd., V601) was injected and stirred to prepare a monomer solution.

  Under a nitrogen atmosphere, 54.9 parts by mass of ethyl lactate was poured into a polymerization tank having a nitrogen inlet, a stirrer, a jacket and a condenser, and the temperature was maintained at 80 ° C. while stirring. The monomer solution in the preparation tank was supplied to the polymerization tank and dropped into ethyl lactate maintained at 80 ° C. at a constant rate over 6 hours. Thereafter, the solution was kept at 80 ° C. for 1 hour to obtain a polymer solution.

(B) Process:
1336 parts by mass of methanol was injected into a purification tank having a stirrer and a jacket. 218 parts by mass of the polymer solution in the polymerization tank was supplied to the purification tank and dropped into methanol while stirring to precipitate the polymer, thereby obtaining a polymer dispersion.

(C) Process:
The polymer dispersion in the purification tank was supplied to a vacuum filter having a filter, and the polymer dispersion was filtered using the filter to produce a polymer wet powder. The content of the dispersion medium in the polymer wet powder was 86 parts by mass with respect to 100 parts by mass of the polymer. The content of the dispersion medium was determined by sampling a part of the polymer wet powder, drying it at 80 ° C. for 24 hours, and measuring the solid content.
The produced polymer wet powder was stored for 18 hours in a refrigerator controlled so that the air temperature was always 0 to 5 ° C.

(D) Process:
1357 parts by mass of methanol was injected into the purification tank. (C) 57 mass parts of polymer wet powders manufactured in the process and stored for 18 hours were put into a purification tank, stirred with a stirrer and dispersed in methanol to obtain a polymer dispersion.

(E) Process:
The polymer dispersion in the purification tank was supplied to a vacuum filter having a filter, and the polymer dispersion was filtered using the filter to produce a polymer wet powder. As the filter, the filter used in the step (c) was used as it was without washing. The content of the dispersion medium in the polymer wet powder was 78 parts by mass with respect to 100 parts by mass of the polymer.
The produced polymer wet powder was stored for 18 hours in a refrigerator controlled so that the air temperature was always 0 to 5 ° C.

(F) Process:
(E) 85.2 parts by mass of the polymer wet powder produced in the step and stored for 18 hours was used for 36 hours at 50 mmHg and 60 ° C. using a vacuum dryer (VACUME pump VO400, manufactured by AS ONE). The polymer powder was obtained by drying.

(Glass transition temperature of polymer)
10 mg of the polymer powder was weighed in a dedicated aluminum pan and measured using a DSC6200 thermal analyzer (trade name) manufactured by Seiko Instrument. The temperature elevation condition was measured at 10 ° C./min.

(Solubility of polymer powder)
900 mg of the polymer powder was added to 4.2 g of propylene glycol monomethyl ether acetate, and dissolution was started with an ultrasonic cleaner. The solubility after 30 minutes was visually observed. The case of complete dissolution was evaluated as ◯, the case of slight turbidity was evaluated as Δ, the case of translucency or white turbidity, or the presence of unnecessary substances was evaluated as ×.

(Preparation of resist composition)
100 parts by mass of polymer powder, 2 parts by mass of triphenylphosphonium triflate as a photoacid generator, and 700 parts by mass of propylene glycol monomethyl ether acetate as a solvent were mixed to obtain a uniform solution, and then the pore size was 0.1 μm. The membrane was filtered through a membrane filter to prepare a resist composition.

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

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

[Example 2]
In the steps (c) and (e), the polymer wet powder was polymerized in the same manner as in Example 1 except that the polymer powder was stored for 6 hours in an air-conditioned room controlled so that the air temperature was always 25 to 30 ° C. Powder was manufactured, a resist composition was prepared, and evaluated. The evaluation results are shown in Table 1.

Example 3
The monomer components were monomer (1-2) 21.3 parts by mass (40 mol%), monomer (2-1) 29.4 parts by mass (40 mol%), monomer (3- 2) A polymer powder was produced in the same manner as in Example 1 except that the weight was changed to 14.8 parts by mass (20 mol%) (wherein R is all methyl groups), and a resist composition was prepared and evaluated. Went. The evaluation results are shown in Table 1.

Example 4
In the step (c) and the step (e), the polymer wet powder was polymerized in the same manner as in Example 3 except that the polymer powder was stored in an air-conditioned room controlled so that the air temperature was always 10 to 15 ° C. for 12 hours. Powder was manufactured, a resist composition was prepared, and evaluated. The evaluation results are shown in Table 1.

[Comparative Example 1]
In the step (c) and the step (e), except that the polymer wet powder was left in a vacuum filter for 6 hours, a polymer powder was produced in the same manner as in Example 1 to prepare a resist composition, Evaluation was performed. The evaluation results are shown in Table 1. During the leaving of the polymer wet powder, the temperature in the vacuum filter reached a maximum of 38 ° C.

[Comparative Example 2]
In the steps (c) and (e), a polymer powder was produced in the same manner as in Example 3 except that the polymer wet powder was left in a vacuum filter for 0.5 hour to prepare a resist composition. And evaluated. The evaluation results are shown in Table 1. During the leaving of the polymer wet powder, the temperature in the vacuum filter reached a maximum of 43 ° C.

The polymer powders of Examples 1 and 2 were excellent in solubility in a solvent, and the resist pattern made of the resist composition obtained from the polymer powder was also good. Similar results were obtained for the polymer powders and resist compositions of Examples 3 and 4.
On the other hand, the polymer powder of Comparative Example 1 was poor in solubility in a solvent, and defects occurred in a resist pattern made of a resist composition obtained from the polymer powder. Similar results were obtained for the polymer powder and the resist composition of Comparative Example 2.

  According to the method for producing a polymer powder of the present invention, a polymer powder having good solubility in a solvent and a polymer powder having good solubility in a solvent can be produced, and a resist composition obtained from the polymer powder A reduction in accuracy, yield, and the like of a circuit formed using a resist pattern made of an object can be suppressed.

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

Explanation of symbols

44 Refrigerator (Environment controlled so that the temperature is always below 35 ° C)

Claims (2)

A step of filtering the dispersion in which the resist polymer is dispersed in the dispersion medium to produce a resist polymer wet powder;
A method for producing a resist polymer wet powder, comprising a step of storing the produced resist polymer wet powder,
A method for producing a resist polymer wet powder, comprising storing the resist polymer wet powder in an environment controlled so that the air temperature is always 35 ° C. or lower.   The manufacturing method of the polymer powder for resists of Claim 1 whose glass transition temperature of the polymer for resists is 125-150 degreeC.

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